development of a pipe loop protocol for lead control

American Water Works Association

RESEARCH FOUNDATION

Development of aPipe Loop Protocolfor Lead Control

Subject Area: Distribution Systems

Development of a Pipe Loop Protocol for Lead Control

The mission of the AWWA Research Foundation is to advance the science of water to improve the quality of life. Funded primarily through annual subscription payments from over 800 utilities, consulting firms, and manufacturers in North America and abroad, AWWARF sponsors research on all aspects of drinking water, including supply and resources, treatment, monitoring and analysis, distribution, management, and health effects.

From its headquarters in Denver, Colorado, the AWWARF staff directs and supports the efforts of over 300 volunteers, who are the heart of the research program. These volunteers, serving on various boards and committees, use their expertise to select and monitor research studies to benefit the entire drinking water community.

Research findings are disseminated through a number of technology transfer activities, including research reports, conferences, videotape summaries, and periodicals.

Development of a Pipe Loop Protocol for Lead ControlPrepared by:

Gregory J. Kirmeyer, Anne M. Sandvig, and Gregory L. PiersonEconomic and Engineering Services, Inc.Bellevue, WA 98005andChester H. NeffIllinois State Water SurveyChampaign, IL 61820

Sponsored by:AWWA Research Foundation6666 West Quincy Avenue Denver, CO 80235

Published by theAWWA Research Foundation andAmerican Water Works Association

Disclaimer

This study was funded by the AWWA Research Foundation (AWWARF).AWWARF assumes no responsibility for the content of the research study

reported in this publication or for the opinions or statements of fact expressed in thereport. The mention of trade names for commercial products does not represent or imply

the approval or endorsement of AWWARF. This report is presented solely for informational purposes.

Copyright 1994by

AWWA Research FoundationAmerican Water Works Association

Printed in the U.S.A.

ISBN 0-89867-757-2 Printed on recycled paper.

IV

Contents

ListofTables ................................................. ix

List of Figures ................................................ xiii

Foreword .................................................... xix

Acknowledgments ............................................. xxi

Executive Summary .......................................... xxiii

Chapter 1 Study Conclusions and Recommended Protocol for theAWWARF Pipe Rack ............................... 1

Study Objectives, 1 Conclusions, 2

Startup Procedures, 4Construction and Operation, 4Characteristics of Data From the Pipe Rack, 5Stability of Metals Levels From the Pipe Rack, 5Distribution System Correlations, 7Summary, 7

Recommended Protocol for the AWWARF Pipe Rack, 8Planning for Pipe Rack Studies, 10Construction, 15Operation, 25Avoiding Pitfalls in Pipe Rack Design and Operation, 30

Recommendations for Statistical Evaluation of Corrosion Control Study Data, 32

Determining Data Normality, 32Evaluation of Data Outliers, 32Tests for Stabilization, 33Determining Treatment Differences, 34

Chapter 2 Introduction and Background ......................... 39

Purpose, 39Regulatory Background, 40

Final Lead and Copper Rule, 40

vi Development of a Pipe Loop Protocol

Related Federal Regulations, 44Summary, 45

Historical Pipe Loop Studies, 48Army Corps of Engineers' Research Laboratory Pipe

Loop System, 48Seattle, Wash., Water Department, 52Portland, Oreg., Water Bureau, 52Greater Vancouver, B.C., Water District, 53Los Angeles, Calif., Department of Water and Power, 53

Illinois State Water Survey AWWARF Pipe Rack, 54Construction, 55Normal Corrosion Test Operation, 55Evaluation of Test Results, 55

Utility Participants, 56Illinois State Water Survey, 57New York City Bureau of Water Supply and

Wastewater Collection, 63Philadelphia Water Department, 63Contra Costa Water District, 64Fort Worth Water Department, 64Portland Water Bureau, 64

Chapters Methods and Materials .............................. 67

Illinois State Water Survey, 67Background, 67Pipe Rack Construction and Startup, 67Need to Precondition Test Loops, 68Flushing Study, 69Control and Operation of the Pipe Rack, 70Corrosion Coupon Testing, 72

Corrosion Treatment Studies, 72Philadelphia Water Department, 72New York City Bureau of Water Supply and

Wastewater Collection, 75 Distribution System Correlation Studies, 78

Contra Costa Water District, 79Fort Worth Water Department, 81Portland Water Bureau, 85

Chapter 4 Discussion and Analysis of Results ..................... 91

Illinois State Water Survey, 91 Test Loop Hushing Study, 91

Contents vii

Water Quality Monitoring and Variability, 95Statistical Evaluation of the Trace Metal Data, 105ISWS Pipe Rack Operating Problems, 106

Treatment Evaluation Studies, 107Philadelphia Water Department, 107New York City Bureau of Water Supply and

Wastewater Collection, 121 Distribution System Correlation Studies, 167

Contra Costa Water District, 168Fort Worth Water Department, 192Portland Water Bureau, 227

Utility Data Comparison and Summary of Findings, 249Pipe Rack Data Comparison, 249Distribution System Data, 255Summary of Findings, 257

Chapters Future Research Needs .............................. 261

Appendix A: Schematics for Historical Pipe Loop Studies ........... 263

Appendix B.I: Construction and Operation Procedures OriginallyRecommended to Utility Participants ............... 273

Appendix B.2: Original Sample Program Design ................... 287

AppendixC: Statistical Background ............................. 293

Appendix D: Public Information Items and Materials forImplementing Home Tap Monitoring, Fort WorthWater Department ................................ 297

Appendix E: Example Bid Documents for Constructing theAWWARF Pipe Rack .............................. 317

Appendix F: ISWS Corrosion Coupon and Insert Test Results ....... 341

Appendix G: Water Quality Data From the Pipe Rack andDistribution System Monitoring ..................... 347

References .................................................. 415

List of Abbreviations .......................................... 419

Tables

1.1 Pipe rack study experimental plan 141.2 Common corrosion control chemicals 201.3 Example equipment list and costs for example pipe rack

installation 241.4 Estimated costs for additional items involved in pipe rack

construction 251.5 Numbers of metals samples needed for various confidence

intervals and accuracy levels 291.6 Wilcoxon signed rank test for Loop 5 and control loop 351.7 Comparison of lead levels in Loops 6 and 8 36

2.1 Interrelationships of corrosion control treatments for lead andcopper with other regulatory and water quality issues 46

2.2 Summary of historical pipe loop installations 492.3 Water supply information for utility participants 5 82.4 Treatment information for utility participants 592.5 a Water quality information for utility participants (Contra Costa

and Fort Worth) 612.5b Water quality information for utility participants (New York

City, Philadelphia, and Portland) 62

3.1 Philadelphia Water Department water quality testing protocol,Baxter WTP pipe rack 74

4.1 Effects of flushing procedures on metals concentrations fromlead-soldered copper tube test loops 92

4.2 Water quality of flowing samples collected ahead of lead-soldered copper tube loops, AWWARF model pipe rack, Illinois State Water Survey 96

4.3 Water quality of standing samples from lead-soldered copper test Loop 1, AWWARF model pipe rack, Illinois State Water Survey 98



ix

x Development of a Pipe Loop Protocol

4.6 Water quality of standing samples from AWWARF lead loops,Philadelphia Water Department, Baxter WTP 108

4.7 Water quality of standing samples from AWWARF lead-solderedcopper loops, Philadelphia Water Department, Baxter WTP 115

4.8 Water quality of standing samples from AWWARF copper loops,New York City,Croton supply 123

4.9 Water quality of standing samples from AWWARF lead-solderedcopper loops, New York City, Croton supply 126

4.10 Water quality of standing samples from AWWARF lead loops,New York City, Croton supply 131

4.11 Water quality of standing samples from AWWARF lead loops,New York City, Catskill Delaware supply 133

4.12 Water quality of standing samples from AWWARF copper loops,New York City, Catskill Delaware supply 144

4.13 Water quality of standing samples from AWWARF lead-solderedcopper loops, New York City, Catskill Delaware supply 152

4.14a Summary of water quality data, Contra Costa AWWARFpipe rack 168

4.14b Summary of water quality data, Contra Costa AWWARFpipe rack 169

4.15 Summary statistics for lead and copper levels for pipe rack and distribution system tap samples, Contra Costa Water District 181

4.16 Ratios of standard deviation to mean for average lead andcopper levels, Contra Costa Water District 186

4.17a Summary of water quality data, Fort Worth lead-solderedcopper loops 194

4.17b Summary of water quality data, Fort Worth lead-solderedcopper loops 195

4.17c Summary of water quality data, Fort Worth lead-solderedcopper loops 196

4.18a Summary of water quality data, Fort Worth lead loops 197 4.18b Summary of water quality data, Fort Worth lead loops 198 4.18c Summary of water quality data, Fort Worth lead loops 1994.19 Summary statistics for lead and copper levels for pipe rack

and distribution system tap samples, Fort Worth Water Department, lead-soldered copper sites 211

4.20 Ratios of standard deviation to mean for average lead andcopper levels, Fort Worth Water Department, lead-solderedcopper sites 216

4.21 Summary statistics for lead levels for pipe rack and distribution system tap samples, Fort Worth Water Department, lead service sites 221

4.22 Ratios of standard deviation to mean for average lead levels,Fort Worth Water Department, lead service sites 224

Tables xi

4.23a Summary of water quality data, Portland Water Bureau,AWWARF pipe rack 228

4.23b Summary of water quality data, Portland Water Bureau,AWWARF pipe rack 229

4.24 Summary statistics for lead and copper levels, pipe rack anddistribution system tap samples, Portland Water Bureau 241

4.25 Ratios of standard deviation to mean for average lead andcopper levels, Portland Water Bureau 246

4.26 Comparison of pipe rack water quality data from all piperack studies 251

4.27 Comparison of ratios of standard deviation to mean for leadand copper levels from all pipe rack studies 253

4.28 Summary of comparison between tap and pipe rack metalslevels for lead-soldered copper materials 256

4.29 Summary of comparison between tap and pipe rack lead levelsfor lead service connections 256

Figures

1.1 AWWARF pipe rack 31.2 Copper, lead, and pH levels from ISWS pipe rack 61.3 Three periods associated with metals levels during a pipe rack

study 81.4 Actual pipe rack data exhibiting three periods during two pipe rack

studies 91.5 Implementation of AWWARF pipe rack testing 111.6 Lead tube test loop for AWWARF pipe rack 171.7 Soldered copper test loop for AWWARF pipe rack 181.8 Example pipe rack schematic 221.9 Example elevation of pipe rack 231.10 Example floor plan of pipe rack 231.11 Box and whiskers plot of lead levels, control and Loop 5, days

230 through 322 361.12 Box and whiskers plot of lead levels, Loops 6 and 8, days 230

through 322 37

3.1 Philadelphia pipe rack schematic 743.2 New York City pipe rack schematic 773.3 Contra Costa pipe rack 803.4 Fort Worth pipe racks 833.5 Portland Water Bureau pipe rack 86

4.1 Effect of flushing on copper dissolution 934.2 Effect of flushing on zinc dissolution 934.3 Effect of flushing on lead dissolution 944.4 Copper in standing samples 1044.5 Lead in standing samples 1044.6 Variation of pH of samples during study 105 4.7a Total lead levels, weeks 1 through 48, Baxter lead loops 109 4.7b Total lead levels, weeks 1 through 48, Baxter lead loops

(reduced scale) 1114.8 Total lead levels, weeks 25 through 48, Baxter lead loops 1124.9 Box and whiskers plot of lead levels, weeks 25 through 48,

Baxter lead loops 1144.10 Total lead levels, weeks 1 through 48, Baxter lead-soldered

copper loops 116

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xiv Development of a Pipe Loop Protocol

4.11 Total copper levels, weeks 1 through 48, Baxter lead-solderedcopper loops 117

4.12 Total lead levels, weeks 25 through 48, Baxter lead-solderedcopper loops 118

4.13 Box and whiskers plot of lead levels, weeks 25 through 48,Baxter lead-soldered copper loops 120

4.14 Box and whiskers plot of copper levels, weeks 1 through 48,Baxter lead-soldered copper loops 120

4.15 Total copper levels, Croton copper loops 1244.16 Box and whiskers plot for copper levels, Croton copper loops 1254.17 Total lead and copper levels, Croton lead-soldered copper loops 127 4.18a Estimated trend line for lead levels, Croton lead-soldered copper

Loop 1, all data 128 4.18b Estimated trend line for lead levels, Croton lead-soldered copper

Loop 1, days 145 through 264 1284.19 Box and whiskers plot of lead levels, Croton lead-soldered copper

loops, days 145 through 264 1294.20 Box and whiskers plot of copper levels, Croton lead-soldered

copper loops, all data 1304.21 Total lead levels, Croton lead loops 1324.22 Box and whiskers plot of lead levels, Croton lead loops, all data 1324.23 Total lead levels, Catskill Delaware lead Loops 3 and 4 1344.24 Total lead levels, Catskill Delaware lead Loops 5 and 6 1354.25 Total lead levels, Catskill Delaware lead Loops 7 and 8 136 4.26a Estimated trend line for lead levels, Catskill Delaware lead

control Loop 3, days 230 through 322 138 4.26b Estimated trend line for lead levels, Catskill Delaware lead

control Loop 3, days 279 through 322 138 4.27a Estimated trend line for lead levels, Catskill Delaware lead

Loop 5, all data 139 4.27b Estimated trend line for lead levels, Catskill Delaware lead

Loop 5, days 230 through 322 139 4.28a Estimated trend line for lead levels, Catskill Delaware lead


Loop 6, days 230 through 322 140 4.29a Estimated trend line for lead levels, Catskill Delaware lead


Loop 8, days 279 through 322 142 4.30a Box and whiskers plot of lead levels, Catskill Delaware lead

loops, all data 143 4.30b Box and whiskers plot of lead levels, Catskill Delaware lead

loops, days 230 through 322 143

Figures xv

4.31 Total copper levels, Catskill Delaware copper Loops 3 and 4 1454.32 Total copper levels, Catskill Delaware copper Loops 5 and 6 1464.33 Total copper levels, Catskill Delaware copper Loops 7 and 8 147 4.34a Estimated trend line for copper levels, Catskill Delaware copper

Loop 3, all data 149 4.34b Estimated trend line for copper levels, Catskill Delaware copper

Loop 3, days 230 through 322 149 4.35a Estimated trend line for copper levels, Catskill Delaware copper

Loop 5, all data 150 4.35b Estimated trend line for copper levels, Catskill Delaware copper

Loop 5, days 230 through 322 150 4.36a Box and whiskers plot of copper levels, Catskill Delaware copper

loops, all data 151 4.36b Box and whiskers plot of copper levels, Catskill Delaware copper

loops, days 230 through 322 1514.37 Total lead levels, Catskill Delaware lead-soldered copper Loops

3 and 4 1544.38 Total lead levels, Catskill Delaware lead-soldered copper Loops

5 and 6 1554.39 Total lead levels, Catskill Delaware lead-soldered copper Loops

7 and 8 1564.40 Total copper levels, Catskill Delaware lead-soldered copper

Loops 3 and 4 1574.41 Total copper levels, Catskill Delaware lead-soldered copper

Loops 5 and 6 1584.42 Total copper levels, Catskill Delaware lead-soldered copper

Loops 7 and 8 159 4.43a Estimated trend line for lead levels, Catskill Delaware

lead-soldered copper Loop 6, all data 161 4.43b Estimated trend line for lead levels, Catskill Delaware

lead-soldered copper Loop 6, days 230 through 322 161 4.44a Estimated trend line for lead levels, Catskill Delaware

lead-soldered copper Loop 7, all data 162 4.44b Estimated trend line for lead levels, Catskill Delaware

lead-soldered copper Loop 7, days 180 through 322 162 4.45 a Estimated trend line for copper levels, Catskill Delaware

lead-soldered copper Loop 5, all data 163 4.45b Estimated trend line for copper levels, Catskill Delaware

lead-soldered copper Loop 5, days 180 through 322 163 4.46a Box and whiskers plot of lead levels, Catskill Delaware

lead-soldered copper loops, days 230 through 322 165 4.46b Box and whiskers plot of lead levels, Catskill Delaware

lead-soldered copper loops, all data 165 4.47a Box and whiskers plot of copper levels, Catskill Delaware

lead-soldered copper loops, all data 166

xvi Development of a Pipe Loop Protocol

4.47b Box and whiskers plot of copper levels, Catskill Delawarelead-soldered copper loops, days 180 through 322 166

4.48 Influent alkalinity and conductivity levels, Contra Costa piperack 170

4.49 Influent pH and temperature levels, Contra Costa pipe rack 1714.50 Influent total chlorine and dissolved oxygen levels, Contra Costa

pipe rack 1724.51 Standing lead and copper levels, Contra Costa pipe rack 1734.52 Estimated trend lines for lead levels, all data, Contra Costa

Water District 1744.53 Estimated trend lines for copper levels, all data, Contra Costa

Water District 1754.54 Estimated trend lines for copper levels, days 50 through 331,

Contra Costa Water District 1774.55 Estimated trend lines for lead levels, days 150 through 331,

Contra Costa Water District 1784.56 Box and whiskers plot of lead levels, Contra Costa Water District 1794.57 Average and median lead levels, Contra Costa Water District 1824.58 Average and median copper levels, Contra Costa Water District 1834.59 Means and standard deviations for lead levels by sample period,

Contra Costa Water District 1844.60 Means and standard deviations for copper levels by sample

period, Contra Costa Water District 1854.61 Frequency distributions for calculated 1,000-mL lead and copper

samples, Contra Costa Water District 1874.62 Frequency distributions for pipe rack lead and copper samples,

Contra Costa Water District 1884.63 Correlation of lead level measurements, Contra Costa Water

District 1904.64 Correlation of copper level measurements, Contra Costa

Water District 193 4.65a Influent pH levels, Fort Worth Alta Mesa pipe rack 200 4.65b Influent alkalinity levels, Fort Worth Alta Mesa pipe rack 200 4.66a Influent conductivity, Fort Worth Alta Mesa pipe rack 201 4.66b Influent temperature levels, Fort Worth Alta Mesa pipe rack 2014.67 Influent total chlorine residual, Fort Worth Alta Mesa pipe rack 2024.68 Standing lead and copper levels, Fort Worth Alta Mesa pipe rack 2034.69 Estimated trend lines for lead levels, Fort Worth Alta Mesa

pipe rack, all data 2044.70 Box and whiskers plot of lead levels, Fort Worth Alta Mesa

lead-soldered copper loops 2054.71 Box and whiskers plot of copper levels, Fort Worth Alta Mesa

lead-soldered copper loops 205 4.72a Influent pH levels, Fort Worth Como pipe rack 206 4.72b Influent alkalinity levels, Fort Worth Como pipe rack 206

Figures xvii

4.73a Influent conductivity, Fort Worth Como pipe rack 207 4.73b Influent temperature, Fort Worth Como pipe rack 207 4.74a Influent total chlorine, Fort Worth Como pipe rack 208 4.74b Influent dissolved oxygen, Fort Worth Como pipe rack 2084.75 Standing lead levels, Fort Worth Como pipe rack 2094.76 Influent heterotrophic plate count, Fort Worth Como pipe rack 2094.77 Average and median lead levels from Alta Mesa pipe rack and

lead-soldered copper distribution system sites 2124.78 Average and median copper levels from Alta Mesa pipe rack and

lead-soldered copper distribution system sites 2134.79 Box and whiskers plots of lead levels, Fort Worth

lead-soldered copper tap samples and Alta Mesa pipe rack 2144.80 Box and whiskers plots of copper levels, Fort Worth

lead-soldered copper tap samples and Alta Mesa pipe rack 2154.81 Frequency distribution for lead and copper levels, Fort Worth

lead-soldered distribution system sites, calculated 1,000-mL samples 217

4.82 Frequency distribution for lead and copper levels, Fort WorthAlta Mesa pipe rack 218

4.83 Average and median lead levels from Como pipe rack andlead service distribution system sites 222

4.84 Box and whiskers plots of lead levels, Fort Worth leadservice sites and Como pipe rack 223

4.85 Frequency distribution for lead levels, Fort Worth leadservice sites 225

4.86 Frequency distribution for lead levels, Fort Worth Comopipe rack 226

4.87 Correlation of median lead levels, lead service sample 2 andComo pipe rack 226

4.88 Influent pH and alkalinity levels, Portland Water Bureau 2304.89 Influent total chlorine and dissolved oxygen levels, Portland

Water Bureau 2314.90 Influent temperature levels, Portland Water Bureau 2324.91 Standing lead and copper levels, Portland Water Bureau 2334.92 Estimated trend lines for lead levels, all data, Portland Water

Bureau 2344.93 Estimated trend lines for copper levels, all data, Portland Water

Bureau 2354.94 Estimated trend lines for lead levels, days 78 through 379,

Portland Water Bureau 2364.95 Estimated trend lines for copper levels, days 78 through 379,

Portland Water Bureau 2374.96 Box and whiskers plot of lead levels, Portland Water Bureau 2384.97 Average and median lead levels from Portland pipe rack and

lead-soldered copper distribution system sites 242

xviii Development of a Pipe Loop Protocol

4.98 Average and median copper levels from Portland pipe rack andlead-soldered copper distribution system sites 243

4.99 Box and whiskers plots of lead levels, Portland Water Bureau,tap samples and pipe rack samples 244

4.100 Box and whiskers plots of copper levels, Portland Water Bureau,tap samples and pipe rack samples 245

4.101 Frequency distributions for lead and copper levels, PortlandWater Bureau, calculated 1,000-mL tap samples 247

4.102 Frequency distributions for lead and copper levels, PortlandWater Bureau, lead-soldered copper pipe rack 248

Foreword

The AWWA Research Foundation is a nonprofit corporation that is dedicated to the implementation of a research effort to help utilities respond to regulatory requirements and traditional high-priority concerns of the industry. The research agenda is developed through a process of grass-roots consultation with subscribers, members, and working professionals. Under the umbrella of a Five-Year Plan, the Research Advisory Council prioritizes the suggested projects based upon current and future needs, applicability, and past work; the recommendations are forwarded to the Board of Trustees for final selection.

This publication is a result of one of those sponsored studies, and it is hoped that its findings will be applied in communities throughout the world. The following report serves not only as a means of communicating the results of the water industry's centralized research program but also as a tool to enlist the further support of the nonmember utilities and individuals.

Projects are managed closely from their inception to the final report by the foundation's staff and large cadre of volunteers who willingly contribute their time and expertise. The foundation serves a planning and management function and awards contracts to other institutions such as water utilities, universities, and engineering firms. The funding for this research effort comes primarily from the Subscription Program, through which water utilities subscribe to the research program and make an annual payment proportionate to the volume of water they deliver and consultants subscribe based on their annual billings. The program offers a cost-effective and fair method for funding research in the public interest.

A broad spectrum of water supply issues is addressed by the foundation's research agenda: resources, treatment and operations, distribution and storage, water quality and analysis, toxicology, economics, and management. The ultimate purpose of the coordinated effort is to assist water suppliers to provide the highest possible quality of water economically and reliably. The true benefits are realized when the results are implemented at the utility level. The foundation's trustees are pleased to offer this publication as a contribution toward that end.

This report describes the construction, operation, and data results of the installation of the AWWARF pipe rack at several utilities and presents a recommended protocol for use of the pipe rack in corrosion control studies for lead and copper.

Duane L. Georgeson James F. Manwaring, P.E.Chair, B oard of Trustees Executive DirectorAWWA Research Foundation AWWA Research Foundation

xix

Acknowledgments

This study would not have been possible without the participation of the following utilities and their dedicated staffs, specifically:

Contra Costa Water District, Concord, Calif.Edward W. Cummings, Assistant Director of Water Operations Larry J. McCollum, Research Associate Brett Van Cott, Intern, Environmental Careers Program Brad Thorn, Intern, Environmental Careers Program Enjiang Teng, Intern, China Association for International

Exchange of Personnel

Fort Worth Water Department, Fort Worth, Tex.Richard Talley, Laboratory Services Manager Terry Adams, Technical Services Supervisor James Hill, Water Systems Sampler

New York Bureau of Water Supply and Wastewater Collection, New York, N.Y.

Rocco Mastronardi, Jerome Park Demonstration Plant

Philadelphia Water Department, Philadelphia, Pa.Howard Neukrug, Manager, Planning and Technical Services Suzanne Chiavari, Project Manager Steven Pugsley, Project Engineer Matthew Smith, Project Manager Christine Begley, Project Engineer

Portland Water Bureau, Portland, Oreg.Eloise Eccles, Water Quality Engineer Babette Paris, Water Quality Engineer Michael Sheets, Water Quality Inspector William Hyde, Water Quality Inspector Alberta Sierstad, Laboratory Manager Richard Thies, Water Analytical Chemist

xxi

xxii Development of a Pipe Loop Protocol

The Project Advisory Committee Michael Schock, USEPA; Howard Neukrug, Philadelphia Water Department; and Hoover Ng, Gary Stolarik, and David Heumann, Los Angeles Department of Water and Power all provided useful guidance throughout the project as well as helping to ensure the practicality of the final report. We also greatly appreciate the efforts of the AWWARF project officer, Elizabeth Kawczynski.

Finally, we would like to thank Shari Neuenschwander, Diane Running, and Richard Wilson for their skill in preparing the text and figures for this manuscript.

Executive Summary

Background and Approach

The presence of lead and copper in drinking water can be attributed to the corrosion and subsequent leaching of these metals from materials commonly used in home and building plumbing systems. Specifically, the primary sources are copper piping, lead piping, solder containing lead (i.e., 50:50 tin-lead solder), and brass used in fixtures, which can contain up to 80 percent lead and still be termed "lead free." The amount of lead and/or copper that will be measured in the drinking water is dependent on several factors, including the corrosivity of the water, the length of time the water is in contact with the materials, the size of the piping, and the age of the plumbing materials.

Health officials have indicated that lead and copper can have adverse health effects and have set limits to reduce the public's exposure from a variety of sources. The final Lead and Copper Rule, published by the U.S. Environmental Protection Agency (USEPA) in June 1991, established a regulatory process for reducing the public's exposure to lead and copper levels in drinking water. This process included the evaluation and application of various treatment techniques for reducing the levels of these metals in home tap samples, as well as a requirement that all large utilities serving populations greater than 50,000 conduct corrosion control optimization studies. Medium-size and small utilities that exceed preset action levels must also submit a recommended approach for optimal corrosion control treatment to their state agencies for approval. Thus, these utilities need a method for testing corrosion treatments and demonstrating optimization of control of lead and copper.

The objective of this project was to develop a standard protocol for use of the American Water Works Association Research Foundation (AWWARF) pipe rack to evaluate the effectiveness of various treatment options in controlling lead and copper levels in home tap samples. The protocol was to present a practical, hands-on approach, with construction, operation, and data evaluation recommendations based on results from several utilities that had constructed and operated the AWWARF pipe rack.

The project approach involved the participation of several utilities that agreed to build the AWWARF pipe rack or incorporate the rack into their existing corrosion testing system. These utilities provided information that was used to form the basis of the recommended protocol, including a startup flushing study, construction and operating guidelines, and data to evaluate the variability and stability of lead and copper levels from the AWWARF pipe rack. In addition, data were generated on the correlation of pipe rack lead and copper levels to home tap sampling results.

xxm

xxiv Development of a Pipe Loop Protocol

The utilities participating in this study included the Contra Costa Water District, Concord, Calif.; Fort Worth Water Department, Fort Worth, Tex.; Illinois State Water Survey (ISWS), Champaign, 111.; New York City Bureau of Water Supply and Wastewater Collection, New York, N. Y.; Philadelphia Water Department, Philadelphia, Pa.; and Portland Water Bureau, Portland, Oreg. Contra Costa, Fort Worth, ISWS, and Portland built stand-alone pipe racks and evaluated their current water quality conditions with respect to lead and copper leaching. Contra Costa, Fort Worth, and Portland also conducted distribution system monitoring to provide data for a comparison and correlation of pipe rack and home tap sample lead and copper levels. ISWS conducted a flushing study designed to monitorthe effect of various flushing procedures on the reduction of zinc, copper, and lead concentrations in standing samples from the test loops. Philadelphia and New York City incorporated into their existing corrosion pipe racks flow-through test loops patterned after the AWWARF design, and they evaluated various corrosion treatment scenarios, including the use of orthophosphate inhibitors and pH adjustment.

Findings________________________

Study findings are summarized below in a question-and-answer format to facilitate review and provide utilities with concise information about the AWWARF pipe rack that can be used directly in their own presentations or in explanations to others.

What Is the AWWARF Pipe Rack and How Is It Used?

The AWWARF pipe rack was designed to evaluate lead and copper leaching characteristics in a flow-through system that simulated household plumbing. Each rack was designed to contain several individual pipe loops from which standing metals levels could be evaluated for a specific water quality condition. If several waterquality conditions (i.e., several corrosion treatments) were to be tested, one pipe rack would be required for each treatment condition.

Historically, studies involving exposure of pipe coupons and inserts to water in controlled environments have been used to assess corrosion and evaluate corrosion treatment strategies for a wide range of piping materials, but only recently have they been used to evaluate leaching of lead and copper. These studies can generally be classified into one of the following categories: corrosion rate determinations and metals leaching studies. Corrosion rate determinations can be developed from weight loss analysis of metals coupons over a given time period or from one of several electrical instrumentationmethods thatmeasure the corrosion rate instantaneously. Metals leaching studies, on the other hand, examine the actual concentrations of metals from the water in either a recirculating loop or, as with the AWWARF pipe rack, in a flow-through loop constructed from the material of interest.

Executive Summary xxv

What Are the Primary Uses of the AWWARF Pipe Rack?The final Lead and Copper Rule included a requirement that all large

utilities (serving >50,000 population) conduct corrosion control optimization studies and demonstrate "optimal" treatment for lead and copper. Optimal treatment was defined by the USEPA as a corrosion control treatment that minimizes lead and copper levels at users' taps while ensuring that the treatment does not cause the water system to violate any national primary drinking water regulations.

The USEPA published a guidance manual (USEPA 1992) for the final Lead and Copper Rule that provides a step-by-step framework for conducting a corrosion study. One element of the framework includes performing demonstration testing to evaluate the effectiveness of various corrosion control treatments. The AWWARF pipe rack was designed as a demonstration testing device, and its major use is for comparing the effect of various corrosion treatments on metals levels. The use of controlled simulated plumbing systems, i.e., pipe racks, to evaluate corrosion treatments in the demonstration testing phase can be an important methodology for determining optimum reductions in lead and copper levels. It can also be used to assess the secondary impacts of that treatment on a system's overall water quality and regulatory compliance. In addition, results from this AWWARF study indicated that metals levels may respond quickly to changes in incoming water quality due to treatment interruptions. Consequently, the pipe racks may also function as a controlled scientific tool for demonstrating the impact of operational changes on metals levels in the distribution system after full-scale treatment is instituted.

What Equipment Is Normally Included in the AWWARF Pipe Rack?

The AWWARF pipe rack includes metal test loops from which standing metals levels will be measured, a nonmetallic manifold to connect the test loops, flow control devices to maintain a standard flow rate and on-off cycling, and treatment appurtenances to adjust the water quality to the desired condition. The test loops should consist of replicate loops of the material of interest. The choice of lead- or copper-containing material will be dependent on the presence of the material within an individual utility. The recommended minimum number of replicate loops for evaluating lead levels is three; if fewer loops are incorporated there will be less data with which to evaluate the degree of confidence that can be assigned to the results. If copper levels are of concern, however, one loop of copper tube, either with or without lead solder, can be incorporated. The manifold and all other portions of the pipe rack should be nonmetallic so as to prevent metal contamination from sources other than the metallic test loops. Treatment appurtenances must also be included and will vary depending on the treated water quality conditions to be evaluated. Chemicals commonly used for corrosion control include caustic soda, lime, soda ash, sodium bicarbonate, and orthophosphate and silicate inhibitor chemicals.

xxvi Development of a Pipe Loop Protocol

What Are the Important Planning Aspects and Operating Parameters for a Pipe Rack Study?

Planning is the first critical step in performing a demonstration pipe rack study. Pitfalls in pipe rack construction and operation can be minimized through good planning, design, fabrication oversight, and quality control during operation. Providing good supervision of the pipe rack fabrication process, incorporating devices that will ensure adequate mixing of chemical feed solutions, providing for adequate preconditioning of test loops prior to starting normal operations, disinfecting sample ports to prevent high heterotrophic bacteria counts, and providing for consistent control and monitoring of pipe rack operations are just a few of the actions that help prevent problems during operation.

Operation of the pipe rack can be divided into three distinct phases: (1) startup, (2) preconditioning, and (3) normal corrosion testing operations. With respect to startup, flushing was found to be a beneficial practice for lead-soldered copper test loops; therefore, a standard protocol for flushing was developed as part of this project. The term "preconditioning" refers to operation of the pipe rack for a period of time after flushing but before chemical treatments are started. Operation of the pipe racks for approximately 4 weeks without chemical additions would enable the utility to evaluate whether all pipe racks were constructed in a similar fashion and yielded similar results and also would provide a similar starting point for evaluating treatment effects on leaching. If the metals levels were determined to be similar across the racks during preconditioning, treated water could then be introduced and normal corrosion testing operations begun.

The important operating parameters for normal corrosion testing operations include incorporation of a daily on-off cycle at a flow rate established to simulate flow in a home, collection of standing samples for measuring corrosion-related parameters, and collection of running samples for determining influent water quality characteristics and operational consistency. At a minimum, lead, copper, temperature, alkalinity, total and free chlorine, and pH are recommended for analysis on first-flush, standing-water-quality samples. The frequency of collection of standing samples should be based on the expected variability of the results and the length of time over which samples will be collected. Typically, weekly or twice weekly sample collection would be appropriate. Weekly collection of running samples for a variety of water quality parameters at the source and after treatment will provide information on the consistency of the water entering the test loops.

How Long Do the Pipe Racks Need to Be Operated?

A major thrust of this study was to determine the time it took for lead and copper levels to stabilize in the AWWARF pipe racks. Stabilization of metals levels from apipe rack indicates that the pipe materials have reached equilibrium with respect to corrosion or have reached a state in which film formation has become very slow. It is most appropriate to use data that have reached stabilization when determining the impact of various treatments on lead and copper levels

Executive Summary xxvii

because the ultimate goal of a pipe rack study is to determine whether a particular water treatment results in lead or copper levels that are significantly lower than those of the control water.

Based on data from the test loops in this study that stabilized, there appear to be three distinct periods in a pipe rack study: (1) a conditioning period, (2) a transition period, and (3) a stability period. The conditioning period consists of a very rapid drop in metals levels, followed by a transition period in which metals levels are decreasing at a slower rate. In the stability period, metals levels have essentially stabilized. It is very important that the utility operate the pipe racks long enough to ensure that the data used in the evaluation represent this stabilization period.

hi the pipe rack studies in this evaluation, it took from 6 to 9 months for lead levels to stabilize in lead loops and from 3 to 8 months for lead levels in lead- soldered copper loops. Copper levels stabilized in 2 to 8 months. The total length of operation necessary for any individual utility will depend on the characteristics of the metals levels measured during the study. When levels appear to have stabilized, the study should continue until an adequate amount of data has been collected for comparison of treatments. If weekly sampling is assumed, a typical range of 3 to 9 months' worth of additional data may need to be collected after stabilization. Therefore, the total pipe rack operation may typically last for 6 to 18 months in order to account for both stabilization of lead and copper levels and collection of a number of samples adequate to compare treatments. Longer periods may be required if the data are highly variable or a greater degree of statistical confidence in the results is required.

What Are the Costs Associated With an AWWARF Pipe Rack Study?

Based on the experience of the utilities in this study, as well as other pipe rack studies implemented in response to the final Lead and Copper Rule, the construction cost of one AWWARF pipe rack may range from $10,500 to $13,000 in materials and labor. This estimate is meant to provide a reasonable guideline for total construction costs for a pipe rack layout. If several water quality conditions are to be tested, one rack would be needed for each treated water condition. Thus, for a control rack plus three treatment racks, a cost range would be $42,000 to $52,000. Site constraints and individual study needs for each utility will dictate the actual costs that would be incurred by incorporating the AWWARF pipe rack into a corrosion control optimization study.

In addition to construction costs, there will be costs associated with ongoing operation. Startup of the pipe racks may require a full-time operator for a 2- to 4-week period, and routine operations may take approximately 20 h/week. Water quality monitoring costs must also be considered.

xxviii Development of a Pipe Loop Protocol

How Can Data Be Evaluated to Detect the Impact of Various Treatments on Lead and Copper Levels?

Data sets of lead and copper analyzed from this study indicate that lead datafollowanonnormal distribution. Copper data also usually follow anonnormal pattern but on occasion do approach a normal distribution. The data distributions observed indicate that nonparametric statistics, i.e., the Wilcoxon and Kruskal- Wallace tests, are the most appropriate statistical tools with which to evaluate the data and determine treatment differences. A confidence level can be assigned to these tests to provide a statistical basis for evaluating the extent of the treatment difference. Box and whiskers plots can be used to display the data characteristics visually as well. It is important to remember that corrosion control evaluation requires a special blend of expertise and common sense. Interpretation of these statistical tests must be coupled with a practical understanding of their limitations.

Do Lead and Copper Levels From a Pipe Rack Correlate to Home Tap Sample Results?

Lead levels from lead pipe racks were all much higher than tap sample levels from homes with lead services, as was the case with lead-soldered pipe racks and homes with lead-soldered copper piping. Copper levels measured from home tap samples were very similar to pipe rack copper levels after stabilization, however. The similarity in copper levels between the pipe rack and home tap samples provides an indication that treatment results from the pipe rack may translate to actual reductions in copper levels in the distribution system; however, the same cannot be said for lead levels.

What Are the Major Drawbacks Associated With the AWWARF Pipe Rack?

Although the AWWARF pipe rack has been demonstrated to be effective in evaluating the impact of various treatments on standing lead and copper levels, there are some drawbacks to its use. To generate meaningful, statistically valid data, the pipe racks may need to be run for as long as 18 months to obtain adequate data with which to make treatment comparisons. Also, the metals levels measured in a pipe rack study are impacted by the nature and consistency of the incoming water quality conditions. In some cases, stability of metals levels may not be observed, or the seasonal nature of the incoming water quality may obscure the observation of stable metals levels. These phenomena also occur in sampling of home taps. Given the regulatory time frame in which treatment decisions must be made, utilities may not be able to operate pipe racks long enough to be assured that treatment differences can be detected with the confidence desired. However, even given this time constraint, utilities participating in this study were in many cases able to demonstrate stable metals levels and determine treatment differences over a 12-month period. In addition, this study demonstrated that the AWWARF pipe rack may be a valuable tool for evaluating lead and copper levels in the system on a long-term basis.

Executive Summary xxix

Estimates of total construction costs for a typical pipe rack layout range from $10,500 to $13,000 per rack, which may be a drawback for smaller utilities. To evaluate several treatment conditions against the control water, one rack would be needed for each water quality condition, therefore multiplying this cost by 3,4, or 5, depending on the number of treatment conditions to be tested.

Finally, the variability measured in the lead and copper data from the AWWARF pipe racks in this study was high. It is important to note that similar variability is seen in sampling from home taps conducted to comply with the final Lead and Copper Rule. Nonparametric methods are available with which to evaluate these variable data in a statistically valid manner. The AWWARF pipe rack studies described in this report provide the proper approach to successful application of these methods to evaluate the impact of various treatments on metals leaching. In summary, although results from the AWWARF pipe rack must be considered a relative evaluation of treatment impacts on metals levels, the data can be used for demonstrating optimization.

Conclusions______________________

Corrosion test procedures have improved significantly in the past decade and have expanded from the traditional approach of measuring corrosion rates to focus on water quality degradation caused by corrosion. The AWWARF pipe rack has successfully been constructed and operated by several large utilities and is considered appropriate for developing optimal treatment strategies for lead and copper materials. Although lead levels were highly variable and nonnormal, nonparametric statistical data evaluation techniques can be used to successfully evaluate the data and detect differences in lead and copper levels associated with different types of corrosion treatments.

American Water Works Association

RESEARCH FOUNDATION

American Water Works Association6666 W. Quincy Ave., Denver, CO 80235 303/794-7711

Erratum

Development of a Pipe Loop Protocol for Lead Control

AWWA Research Foundation Report #90650

Published August 1994

Page 35: The formula for Z, which appears at the bottom of Table 1.6, should read as follows:

Where n = number of samples = 6

Z =

n(n + 1)

n(n+ 1)(2n

24

20 -Z-

6(7)(13)

24

-1.99

LIBRARY COPY PLEASE RETURN

Chapter 1

Study Conclusions and Recommended Protocol for the AWWARF Pipe Rack

The purpose of this chapter is to provide a summary of the conclusions of this study along with specific recommendations forutilizing the AWWARF pipe rack in corrosion control evaluations. Details of the background, methods and materials, and specific results from this study are contained in the chapters that follow for readers interested inmore specific information on theproject. This chapter is divided into four sections:

Study Objectives Conclusions Recommended Protocol for the AWWARF Pipe Rack Recommendations for Statistical Evaluation of Corrosion Control

Study Data

The information in each of these sections can serve as a guide for utilities that incorporate pipe rack studies of metals leaching as part of an overall corrosion control optimization study. Utilities should bear in mind, however, that results from a pipe rack study provide only part of the information necessary to assess what optimum corrosion control may consist of for their particular systems.

In the corrosion study process, utilities must carefully consider the effects a particular treatment may have on distribution system water quality; efficiency of other treatment processes; potential impacts of the finished water on various industrial and municipal water uses; and impacts on the individual utilities' current operations. The useof controlled simulated plumbing systems, i.e., American Water Works Association Research Foundation (AWWARF) pipe racks, to evaluate corrosion treatments in the demonstration testing phase is considered an important methodology for determining optimum water quality conditions for reducing lead and copper levels and is also important in assessing the secondary impacts of treatment on a utility's overall water quality and regulatory compliance.

Study Objectives_____________________________

The objective of this project was to develop a standard protocol for the use of the AWWARF pipe rack in evaluating the effectiveness of various treatment options in controlling lead and copper levels in distribution system tap samples. A

2 Development of a Pipe Loop Protocol

protocol includes the aspects of planning and design, construction and startup, operation and monitoring, and appropriate use of the data to draw valid conclusions. To achieve this objective, several utilities agreed to build the AWWARF pipe rack or incorporate the rack into their existing corrosion testing systems. These utilities provided information on construction and operation of the AWWARF pipe rack as well as input in addressing the following questions:

How long does it take for standing lead and copper levels measured from the test loops to stabilize?

How long should the AWWARF pipe rack be operated to determine statistically valid differences between chemical treatments for corrosion control?

What is the sampling protocol most appropriate to evaluate these differences in treatment?

How should data be evaluated to assess the effectiveness of various chemical treatment approaches?

Do standing lead and copper level results from the AWWARF pipe rack correlate to home tap sampling results?

What are the costs associated with constructing and operating the AWWARF pipe rack?

The Illinois State Water Survey (ISWS), Champaign, ffl.; Contra Costa Water District, Concord, Calif.; Fort Worth Water Department, Fort Worth, Tex.; and Portland Water Bureau, Portland, Oreg., built stand-alone pipe racks with three replicate lead-soldered test loops and evaluated theircurrent water quality conditions with respect to lead and copper leaching. Fort Worth also constructed apipe rack with three replicate lead loops. A schematic of atypical pipe rack with three separate loops without chemical treatments is depicted in Figure 1.1. ISWS, in addition to its pipe rack construction and operation, conducted a flushing study designed to monitor the effects of various flushing procedures on the reduction of zinc, copper, and lead concentrations during startup of the test loops.

The remaining two participating utilities, the Philadelphia Water Department, Philadelphia, Pa, and the New York City Bureau of Water Supply and Wastewater Collection, New York, N.Y., incorporated flow through AWWARF test loops into their existing corrosion pipe racks and evaluated various corrosion treatment scenarios including orthophosphate inhibitors and pH adjustment. Philadelphia and New York City employed a single loop for each treatment so that comparisons among treatments could be made.

Finally, Contra Costa, Fort Worth, and Portland conducted distribution system monitoring to provide data for a comparison and correlation of pipe rack and home tap sample lead and copper levels. Tap samples were collected from houses that fit the targeting criteria in the final Lead and Copper Rule as closely as possible.

Conclusions______________________

The study produced several key conclusions, whichhave been summarized below according to the following subcategories:

Study Conclusions and Recommended Protocol 3


startup proceduresconstruction and operationpipe rack data characteristicsstability of metals levels from the pipe rackdistribution system correlations

Startup Procedures Flushing was found to be a beneficial practice for removing

contamination introduced to the test loops during fabrication and possibly for reducing the time required to establish corrosion equilibrium, and it should therefore be included in startup procedures. The most important aspect is that all loops should be flushed according to a standard protocol.

A two-step flushing procedure that includes flushing with 32 to 86 F (0 to 30 C) water followed by 150 to 160 F (60 to 70 C) water is recommended for soldered test loops. If hot water is not reasonably available, a cold water flushing program would still be considered beneficial. Nonsoldered test loops should be flushed with cold water to avoid any potential effect of increased water temperature on the corrosion process in these materials. Such materials include copper, lead, brass, and others.

Construction and Operation

Pitfalls in pipe rack construction and operation can be minimized through good planning, sound design, fabrication oversight, and quality control during operation.

The statistical difference in lead levels measured from replicate test loops indicates that three replicate loops of lead or lead-soldered copper should be included in the rack for each water quality condition to be tested. If fewer loops are included, there will be less confidence in the results. Use of fewer loops does not mean results are invalid, only that the degree of confidence in the treatment difference may be more difficult to ascertain. For evaluating copper levels however, one loop appears to be sufficient.

Copper levels from copper loops without solder and from lead- soldered copper loops were similar under the same water quality conditions. Therefore, if both lead from lead solder and copper from copper piping are to be evaluated in a pipe rack study, lead-soldered copper loops can serve both functions. There is no need to construct and operate both types of loops.

Although not directly evaluated in this project, operation of the pipe racks for a period of 3 to 4 weeks without chemicals (i.e., preconditioning) would enable a utility to evaluate whether all the pipe racks were constructed in a similar fashion and thereby would provide similar starting points for evaluating treatment effects on leaching.


Characteristics of Data From the Pipe Rack Nonparametric data evaluation techniques were most appropriate for

evaluating data from the pipe rack studies because lead and copper levels from the racks were not normally distributed and generally low numbers of samples were available with which to evaluate treatment differences.

A wide range of metals levels was measured from the pipe racks across the entire study period, and this range could have been caused by one or all of the following:

seasonal or operational changes in incoming water quality inability to maintain consistent treated water quality conditions disturbance to the pipe rack by solenoids or external vibration sloughing off of films

Because the piping was continually exposed to the water in the pipe rack, the variability measured in the metals levels was reduced, possibly because of stabilization of the corrosion process.

The variability measured in lead and copper levels from these studies provides an excellent starting point for determining sampling frequencies appropriate for pipe rack studies.

Metals levels responded quickly to changes in incoming water quality caused by treatment interruptions, as indicated in Figure 1.2; consequently the pipe rack may function as a controlled scientific tool for demonstrating the impact of operational changes and treatment interruptions on the metals levels in the distribution system.

Data from the pipe rack should be viewed as an indicator of the relative effectiveness of treatments rather than as a device to fine tune chemical dosages or operational parameters.

Stability of Metals Levels From the Pipe Rack Lead levels took from 6 to 9 months to stabilize in lead loops and

from 3 to 8 months to stabilize hi lead-soldered copper loops. Copper levels stabilized in 2 to 8 months. Stability was determined by evaluating the change in the slope of the trend line over time. For example, if the slope of the estimated trend line became much flatter as the study progressed, then the data were approaching stabilization. The total length of operation necessary for any individual utility will depend on the characteristics of the metals levels measured during the study. If levels appear to have stabilized, the study should continue until an adequate amount of data has been collected for comparison of treatments.

Stabilization of metals levels from a pipe rack may indicate that the pipe materials have reached equilibrium with respect to corrosion or have reached a state in which film formation has become very slow. It is more appropriate to use only data that have reached stabilization when determining the impact of various treatments on lead and


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100 ^v" 300 Duration of study (days)

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* Loop 1 + Loop 2 D Loop 3

100 *™ 300

Duration of study (days)

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Treatment Interruption

0 200100 """ 300


Figure 1.2 Copper, lead, and pH levels from ISWS pipe rack

400


copper levels. Based on the data from the test loops in this study that had stabilized, there appear to be three distinct periods as corrosion proceeds in a pipe rack study. The first period consists of a very rapid drop in metals levels, followed by a second, transition period in which metals levels decrease at a very slow rate. In the third period, metals levels have essentially stabilized; i.e., the slope of the estimated trend line is approaching zero. It is very important that the utility operate the pipe racks long enough to ensure that the data used in the evaluation represent this third period if possible. These three periods are illustrated in Figures 1.3 and 1.4, which display data taken from AWWARF pipe racks operated for 12 months.

Distribution System Correlations

Copper levels measured in the pipe rack and compared with home tap samples provide a good indication that treatment results from the pipe rack study may translate to actual copper levels in the distribution system.

Lead levels from the pipe rack and from home tap samples were not similar, the difference could be due to variability within and between the sites where data are collected and the short exposure time in the racks versus the long period of exposure of actual home plumbing. Therefore the AWWARF pipe rack cannot be used to predict actual lead levels that will occur at homeowners' taps.

Summary

In summary, corrosion testing procedures have progressed significantly in the past decade and have expanded from the traditional approach of measuring corrosion rates through weight loss analysis to focus on water quality degradation caused by corrosion. The AWWARF pipe rack was successfully constructed and operated by several large utilities. Because lead levels in the racks were highly variable, special methods such as replicate loops within the rack and nonparametric statistical techniques must be used to develop and evaluate data. High variability and nonnormal data also result from sampling at the tap per the final Lead and Copper Rule. This project found that pipe racks can be used successfully to detect differences in lead and copper levels associated with different types of treatments and can be used to determine optimum treatment approaches. It is important to remember that the evaluation requires a special blend of expertise on corrosion and proper data evaluation techniques. The AWWARF pipe racks should be used in the context of relative effectiveness of treatment and not as a tool to fine tune chemical dosages. Finally, the AWWARF pipe racks do not predict the actual metals levels at the customers' taps, nor do they guarantee that a utility will meet a regulatory action level. It should be noted thatmosttypes of corrosion testing, including electrochemical testing procedures, have this same drawback.

<D

3 I

I II IIIConditioning period Transition period

TimeStability period

Figure 1.3 Three periods associated with metals levels during a pipe rack study

Recommended Protocol for the AWWARF Pipe Rack

The AWWARF pipe rack operated continuously for over a year at several locations throughout the United States. The single pipe rack installations at four of these sites (ISWS, Contra Costa, Fort Worth, and Portland) were as designed and specified inLead Control Strategies (EES1990). Two of the study sites (New York City and Philadelphia) installed single test loops similar to AWWARF pipe racks in their treatment evaluation racks and provided a great deal of information related to control and operation of treatment appurtenances as part of their pipe rack studies. The information from all of these studies was synthesized to produce a revised protocol for constructing and operating the AWWARF pipe rack for corrosion control studies.


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50100

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250300

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Standing lead levels, Portland Water Bureau

Loop A

+ Loop B

o Loop C

00

50100 I 200 1 300 T 400

150 250 350Time, days

Figure 1.4 Actual pipe rack data exhibiting three periods during two pipe rack studies


Planning for Pipe Rack Studies

The critical first step in performing a corrosion pipe rack study is to allow enough time and commit enough resources to perform proper planning. Successful planning provides for a well-designed and -constructed pipe rack pilot system, reduces operational problems, and, most importantly, ensures that the data produced are useful and that the objectives of the pipe rack study will be met.

This section outlines the planning process recommended for corrosion control pipe rack studies and provides an overview. It is not the purpose of this section to present all the considerations and possible sources of information that can be used in planning for corrosion control testing. Many of the considerations for corrosion study planning can be found in the U. S. Environmental Protection Agency's (USEPA's) Lead and Copper Rule Guidance Manual, Volume II: Corrosion Control Treatment (USEPA 1992) and in AAWARFs Lead Control Strategies (EES 1990), as well as in other documents in the literature.

There are two key elements in the planning process for pipe rack studies:

1. Establish the specific pilot study objectives.2. Develop an experimental plan, including pilot plant design

requirements.

Development of the pilot plant experimental plan and the design should occur concurrently. A useful experimental plan is specific to the design, whereas a useful pipe rack layout must be designed to meet the specific testing objectives and requirements of the study. Because the pipe rack is the focus of this study, important elements in the planning and implementation process for the pipe rack are depicted in Figure 1.5 and discussed below.

Establishing Specific Pilot Study ObjectivesClear, specific objectives are needed so that development of the experimental

plan and pilot plant design can proceed. Some objectives may be higherpriorities than others. As an example, one primary objective may be to determine the effect of pH adjustment to 8.5 on leaching of copper. A secondary objective would be to compare trihalomethane (THM) formation at pH 8.5 with the control treatment condition at a lower pH. Without clear objectives and without prioritization, the number of pilot plant components can quickly get out of hand, and the likelihood of excessive costs, schedule delays, and a failed pilot program increases dramatically.

Pilot Plant SitingSiting of the pipe rack pilot plant (or plants) must be carefully considered

prior to the development of the experimental plan and the design requirements. Availability of source waters and housing and support facilities are the two major factors that determine where the pipe racks should be set up.

Influent water for the pipe racks should be easily accessible. Depending upon the pilot study objectives, the influent water may be raw, untreated water or it may be finished water. Normally, the influent water (either raw or finished) serves as the control water quality condition in one pipe rack. If there are water sources with


STEP1Develop

Experimental Plan and Design Requirements

o Develop specific objectives o Methods o Materials

STEP 2Finalize Pilot Plant

Design andConstruction

o Space constraintso Number of alternatives to be testedo Chemical feed and storageo Materials to be tested

STEPS Finalize Experimental Plan

o Operational availability o Laboratory services o QA-QC

STEP 4Startup

Operations

o Leak testingo Flushingo Preconditioningo Fine tune treatment appurtenances

STEP 5 Perform Pipe Rack Testing

oOn-off cyclingo Water quality sampling

STEP 6Evaluate Test Data

o Data distributiono Determine stabilityo Evaluate treatment differences

Figure 1.5 Implementation of AWWARF pipe rack testing

significantly differentwaterquality characteristics that enterthedistributionsystem and it is desired to perform corrosion testing for these sources, it may be necessary to locate Hie pipe racks at separate sites in order to access the different sources.

Whenever possible, it is best to site pipe rack pilot plants within existing facilities. The pipe rack system should be enclosed in a structure that has adequate lighting, power, heating, ventilation, plant water, and drainage. The pipe racks and


associated chemical feed equipment should be situated so that they do not interfere with existing water operations. It is desirable to have a dedicated work area for the pilot plant operators), including a benchtop space and a sink.

Planning for OperationsPlanning for pipe rack operations must take into consideration the project

timeline, operations personnel, laboratory services, and availability of materials and chemicals.

Project Timeline. Based on results from this study, it can take 3 to 9 months for lead levels to stabilize and 2 to 8 months for copper levels to stabilize in a pipe rack. In addition, it is desirable to have several weeks' or months' worth of stable lead and copper levels with which to make treatment comparisons. The length of time necessary for collection of data on stable lead and copper levels will depend on the variability of the results and the confidence and accuracy levels desired for making treatment comparisons; however, a typical range might be 3 to 9 months. Therefore, the total length of a pipe rack pilot operation could typically be anywhere from 6 to 18 months. Operation time includes a startup period, which can be as long as 6 weeks.

Operators. The major planning considerations for pilot plant operators are (1) who will provide the operator or operators, (2) what skills are required of the operator(s), and (3) how much time will be required of the operators).

Pilot plant operators may be provided by the utility, by the utility's consultants, or by outside contracted personnel. The level of operator skill required should be approximately that of a certified water treatment operator or a person with some formal training in bench chemistry techniques or water quality engineering operations. The types of tasks required of the operator are listed below.

Mix chemical feed solutions and adjust feed pumping rates. Collect samples and perform field analytical tests. Conduct routine maintenance on pumps, mixers, valves, etc., and

troubleshoot as required. Record data and observations.

Regardless of the operator's background or level of expertise, training of the operator(s) on specific pipe rack operations should be provided during the startup phase of the study.

The number of operator man-hours required during routine pipe rack operations is about 20h/week. During the initial startup and training period, it should be assumed that one operator and other support staff will be required full-time.

Laboratory Services. The availability of adequate laboratory services is essential, not only for the routine analyses required for the pilot study but also as a major element of the quality assurance-quality control (QA-QC) effort. Most analyses performed with field test kits should be checked periodically against duplicate samples measured by a certified laboratory. It is most desirable to use one laboratory that is certified by the state to perform all the types of analyses required for the study. This practice will save time and money for sample transport and will help simplify data management.


MaterialsandChemicals. Availabilityofmaterialsandtreatmentchemicals required for the pilot study is also a significant planning consideration. Concerning pilot plant materials, plan on using equipment and components that are known to be reliable and are relatively easy to obtain from a local vendor. Utilization of unusual, discontinued, or cannibalized models of components (e.g., pumps, flowmeters, valves, etc.) should be avoided because if it becomes necessary to replace them during the study it may not be possible to find the same or an equivalent model. If lead pipe is a material to be tested, the appropriate size often takes several weeks to obtain.

Treatment chemical availability is generally not a problem in North America. It is best to plan to use chemicals available from a reliable local supplier if possible. If proprietary phosphate and/or silicate inhibitor chemicals are to be tested during the pilot study, it is advisable to select a type of product that is manufactured by more than one chemical company. Consideration should also be given to generic inhibitor chemicals for testing, such as using phosphoric acid in place of aproprietary sodium orthophosphate product or blending zinc chloride with phosphoric acid to make zinc orthophosphate.

Development of Experimental Plan and Design RequirementsAfter specific pilot study objectives have been established and pilot plant

siting and operational issues have been identified and resolved, the culmination of the planning phase is to develop a draft experimental plan and the design requirements. These two tasks should be performed concurrently, as they are closely interrelated.

Experimental Plan. The experimental plan should be a "stand-alone" working documentprimarily for use by the operator and other key project personnel. The experimental plan also documents the specific objectives, methods, materials, and quality control measures of the pipe rack study that can later be included in a corrosion control study report.

The experimental plan should contain all the pieces of information the operator needs to successfully operate the pilot plant. Some of the sections may need to be added to and/or modified during the startup and operation of the pilot plant. Therefore, it is recommended that the experimental plan be kept in athree-ring binder to allow for removal of outdated pages and insertion of revisions as necessary. Table 1.1 contains an example outline of the items that shouldbe included in anexperimental plan.

Using the examples in Table 1.1 and in the following sections of this chapter and the other planning elements described earlier in this chapter, a draft of the experimental plan can be prepared. A final version of the plan should not be produced until after the detailed design of the pipe rack pilot plant is completed, keeping in mind that some revisions to the final version are likely as the pipe racks are constructed, installed, and started up.

Design Requirements. In developing the specific design requirements for the AWWARF pipe rack, the following should be considered:

space constraints at the site(s) selected for the pipe racks available and desired water flow rates and pressures number of treatment alternatives that will be tested chemical feed and equipment and storage requirements types of materials to be tested (e.g., lead, copper, iron)


Table 1.1 Pipe rack study experimental plan

I. Objectives of Pipe Rack Testing

It. Pilot Plant Physical Description

A. SiteB. Pipe Rack DescriptionC. Chemical Feed System Description

III. Operations

A. ScheduleB. Pilot Plant Operating Procedures

1. Flow Control and Calibration2. Startup Procedures3. Normal and Routine Procedures

C. Sample Collection ProceduresD. Sample Handling and Management ProceduresE. Analytical Methods and Procedures

IV. Quality Assurance-Quality Control

A. OperationsB. Analytical Methods

V. Appendices

A. Chemical Feed Preparation ProceduresB. Operations Records FormsC. Analytical Data Forms

Consideration should also be given to who will construct the pipe racks, where they will be constructed, and how they will be transported from the construction site to the testing site(s). These considerations may dictate specific features of the pipe rack design, including the size and type of pipe rack support system and the size of prefabricated portions of the pipe racks. For example, will the racks be mounted on a wall, or is it better to have them freestanding? Once constructed, can the pipe loops or racks be transported without great risk of damage? Will the prefabricated pieces fit through doorways at the pilot plant site?

Who Should Consider Use of the AWWARF Pipe Rack?Corrosion testing and control is more art than science. Until recently,

corrosion control focused on materials deterioration; now, metals leaching is also a significantconcern. AWWARFpipe rackdevelopmentstudieshaveprovidedthe first attempts to consistently and comprehensively evaluate metals leaching in drinking water supplies. To produce valid data for corrosion control optimization studies, the AWWARF rack must be designed, constructed, and operated properly. Such a project takes special expertise, time, and a significant expenditure of money. Thereforeitis recommended that only largeutilities(i.e.,serving>50,000population) or utilities that are willing to invest in consultant or university resources consider using the AWWARF pipe rack.


The AWWARF pipe rack is considered appropriate for developing treatment strategies for lead and copper materials, i.e., lead-soldered joint, lead piping, and copper piping. Electrochemical testing methods do not seem to be as appropriate for lead solder or lead materials as are AWWARF pipe racks. This is the authors' opinion, and others in the conosionfield will doubtless disagree. The AWWARF pipe rack will work very well for copper leaching; however, other methods, specifically electrochemical procedures, can likely produce valid results for copper in a shorter time and at less cost. Thus, for utilities that have only a copper problem, an AWWARF pipe rack will work very well, but other methods should also be considered, as they may produce equivalent results.

Construction

Pipe rack construction can be divided into three main areas:

1. manifold construction2. corrosion test loop fabrication3. treatment appurtenance selection

Detailed specifications for each of these items should be prepared during the planning stages of a corrosion study. Specifications should include product information as well as detailed information on assembly of each component Each of these areas is discussed below, followed by a summary that incorporates the recommendations into an overall example of an entire pipe rack layout

Manifold

Polyvinyl chloride (PVC) pipe should be used for the manifold and all other portions of the pipe rack, with the exception of the test loops. Use of PVC pipe will preventmetals contamination from non-test loop piping sections. Schedule 80 PVC is recommended for use in the manifold to provide additional rigidity to the model. Threaded, flanged, or coupled fittings may be used to connect piping sections; however, threaded connections may be difficult to unscrew if the manifold must be taken apart Strap wrenches should be used to tighten threaded plastic joints, and care should be taken not to overtighten these fittings. PTFE tape, rather than pipe joint sealing compounds, should be used to connect threaded PVC sections in the manifold because paste-type sealants could contaminate the system.

PVC check valves are recommended to isolate the test sections during no- flow conditions. Sample valves should also be made of PVC and should be located as close to the outlet end of the test sections as possible to provide the largest usable volume of standing water for sampling. Sample valves should be chlorinated and rinsed prior to installation to prevent bacterial contamination.

Test LoopsThe piping materials to be tested in the pipe rack must be determined during

the planning phase of a corrosion study. The test loop material should be based on each utility's corrosion conditions and the prevalence of materials in its system. Whether lead-soldered copper loops or lead loops are incorporated, the variability of lead levels measured from controlled pipe rack studies during this project indicates thatmultiple loops of the same material exposed to the same water quality conditions


should be incorporated into the pipe rack if lead levels are being evaluated. The original AWW ARFpipe rack design, which included three replicate loops of the same material, is sufficient for evaluating lead leaching frombothlead-soldered copper and lead loops, whereas one loop is adequate for evaluating copper leaching.

Lead Test Loops. If lead tube is to be studied in the pipe rack, the dimensions of the test loops should coincide with lead service line dimensions for the particular utility. Dimensions for the original lead test loops in the A WWARF pipe rack were ¥1- in. (12.7-mm)IDwitha 1/4-in. (6.35-mm) wall. The length and diameter of the lead tube test section will determine the total volume of water available for chemical analysis. It is important to choose apipe length that will have enough usable volume in the loop for analysis of all parameters. Lead tube can be purchased directly from a local manufacturer specializing in extruded lead products and then can be cut into replicate test sections and formed into loops or, if space is adequate, left uncoiled. If dresser couplings are used to connect the test loop to the manifold, care should be taken not to clamp the couplings too tightly. Lead pipe is very soft, and flow could be restricted in the test section. Solder may be applied externally to connect vertical sections and increase loop rigidity. Figure 1.6 contains a schematic of a lead tube test loop.

Copper Test Loops. For soldered copper or copper-only test loops, 60 ft (18.3 m) of typeLV6-in. (12.7-mm) coppertube is recommended. For soldered copper loops, the tube can be cut into 36-in. (9.14-cm) vertical lengths and 6-in. (15.24-cm) horizontal lengths, which can then be soldered together at 90-degree angles with 50:50 lead-tin solder (see Figure 1.7). The quality of workmanship should be similar to that provided by local licensed plumbing contractors. With soldered copper loops, the amount of solder used for each loop should be recorded. The plumber can be provided with apreweighed roll of solder and the weight of solderused for each loop documented. As a guideline, several of the utilities in this study used between 55 and 60 g of solder for a test loop with 36 elbows and 2 adapters soldered, or a total of 74 joints. This amount is equivalent to 0.16 to 0.18 Ib (72.6 to 81.6 g) of solder per 100 joints. To reduce the variability in the soldering process, the same plumber should construct all test loops. The plumber should be instructed to lay out all components of each test loop and solder one joint in each loop consecutively. For example, if there are 5 joints to be soldered in each of 3 loops (15 total), the following sequence for soldering could be used:

Soldering sequence

Loop 12345

1 16 7 12 13225 8 11 143 34 9 10 15

With this method, a preweighed amount of solder would be set aside for each test section. When the plumber moved between replicate test loops to solder joints, the specific solder set aside for that section would be used. This procedure will allow the total amount of solder used per test loop section to be determined.


Pipe Strap

Solder Fill

Reinforced PVC Tubing. 1"

36"

Ji '1

0.5" I.D., 0.25" Wall Lead Tube

11/4" HOM Clamp, Stalnles* Steel

Source: EES 1990Figure 1.6 Lead tube test loop for AWWARF pipe rack


36"

44"

Pip* Strap

Shelf Support (Top & Bottom)

0.5" 90 Deg. Elbow* (50:50 Solder Connection*)

0.5" Type LCopper Tube

(9 Loop*)

38"

Male Adapter (0.5" x 0.5")

Source: EES 1990Figure 1.7 Soldered copper test loop for AWWARF pipe rack


General Construction IssuesTest loop sections should be constructed using standard plumbing practices.

Pipe materials should be inspected for defects and uniformity, and pipe ends should be reamed to remove any material that might cause flow distortion in the loop. New piping materials are recommended for use in the AWWARFpipe rack. Incorporating excavated lead service lines or plumbing removed from a residence directly into a pipe rack has not been studied extensively; however, preliminary evidence suggests that unavoidable disturbance of the corrosion films may cause highly erratic metals levels, which may actually take longer to stabilize than metals levels measured from new materials. Nevertheless, the rack is designed to accommodate old pipe, and the final decision on incorporation of used piping is a site-specific one.

Test loops may be installed in a horizontal orientation, but some sacrifice in data correlation as compared to data from vertically designed loops will result The primary concern with either orientation is the accumulation of air and/or sediment within the test loops, which must be prevented. The pipe rack water pressure should be maintained near the operating pressure of the water supply during static conditions in the test loops to eliminate air problems.

A U.S. Army Corps of Engineers' Construction Engineering Research Laboratory (CERL) pipe loop system that incorporates coupons rather than flow- through leaching loops can be incorporated into the rack to evaluate the weight loss characteristics for other materials of interest (see Figure 1.1). A similar corrosion tester unit, such as the insert sleeve designed by Reiber (1989), can also be incorporated for this purpose. Additional pipe insert specimens can be utilized by connecting several CERL insert assemblies in series. These alternative corrosion test racks may be substituted for the CERL pipe loop to increase the number of weight loss measurements.

Treatment AppurtenancesSpecific requirements for chemical feed systems will depend primarily on the

treatment alternatives to be studied in the pipe rack system. In the USEPA' s Guidance Manual for the Final Lead and Copper Rule (USEPA 1992), available corrosion control treatment technologies were identified as pH and/or alkalinity adjustment, calcium adjustment, and corrosion inhibitor addition. It is important to note that the water quality targets are most important in pipe rackstudies, not the specific chemical to be used in final design.

Thus, the simplest and easiest-to-find chemicals should be used at this stage. Chemicals typically used to provide these treatments include caustic soda, lime, soda ash, sodium bicarbonate (CO2), and orthophosphate and silicate inhibitor chemicals. Table 1.2 contains information on the effects of each of these chemicals and the form in which they are usually available. The chemicals are available as powders, which can be mixed in a solution feed tank, or as liquids. To maintain a homogeneous feed solution, a mixer should be incorporated into the solution tank and a maximum time between mixing new batches of solution (i.e., 3 to 5 days) should be specified. Manufacturers' recommendations for chemical storage and handling should be observed. Several inhibitor chemicals may be less soluble at lower temperatures; therefore it is important to understand the material specifications for the chemical chosen, as well as the environmental conditions at the pipe rack site. Finally, carbon dioxide is available as a gas that can be bubbled into solution.


Table 1.2 Common corrosion control chemicals

Chemical Effect Form Comments

NaOH (caustic soda)

Ca(OH)2 (hydrated lime)

NaCOa (soda ash)

NaHCO3 (sodium bicarbonate)

Orthophosphates Sodiumphosphates

Zincorthophosphates

Phosphoric acid

Silicates Sodium silicates Potassium silicates

Elevates pH; converts excess C02 to alkalinity species.

Elevates pH, alkalinity, and calcium content.

Increases alkalinity; moderate increase in pH.

Increases alkalinity; little increase in pH.

Corrosion inhibition.

Corrosion inhibition.

Anhydrous white solid beads, flakes, or liquid. 98% purity NaOH. 76% and 50% purity Na2O. Solution feed.

White powder. 95 to 98% purity Ca(OH)2. 74% purity CaO. Slurry feed.

Anhydrous white powder. 98% purity. Solution feed.

White powder. 9% purity. Solution feed.

Liquid. Percent P04 varies with chemical. Solution feed.

Liquid. 28-30% purity SiO2. Solution feed.

Use extreme caution in handling. pH control may be difficult in poorly buffered waters.

O&M intensive. pH control may be difficult in poorly buffered waters.

Good alkalinity adjustment. Relatively expensive.

Lime slurry feeds present more complicated chemical handling and opera tional control procedures. A saturated solution can be made by dumping hydrated lime into the solution feed tank, allowing the solids to collect at the bottom, and drawing chemical feed solution from the top of the tank. Care must be taken to maintain consistent solution feeds both within and between batches. Also, the potential for chemical feed lines becoming clogged is much greater than with chemicals available in liquid form.

The feed line from the solution tanks should contain a calibration tube followed by a variable-speed feed pump. The pump should be calibrated at the beginning of the study and checked at weekly intervals during operations. The variable-speed pump can be controlled by an on-off timer set to the same operating cycles as the on-off control for flow through the pipe rack. The pump size, chemical flow rate, and chemical usage rates will depend on the solution strength of the chemical, the target water quality conditions, and the on-off operating cycle of the rack. The chemical feed solution must be completely mixed with the influent water prior to the water entering the test loops. This mixing can be accomplished by incorporating an in-line static mixer into the influent line. Under full-scale applica tion, chemicals may transform in the distribution system; however, it would be difficult to physically simulate this transformation in a surrogate pipe rack installation. To provide for additional mixing and contact time between the chemical and the influent water, a pressurized vessel such as a water heater may also be installed just downstream from the mixer.


Operational control of key water quality parameters such as pH, alkalinity, and inhibitor concentration may be provided manually or by automatic control systems. Automatic control systems introduce additional complexity and are chosen by individual preference. An optional side stream constructed parallel to each rack could be incorporated; it would contain a continuous pH recorder. This arrangement would allow more precise monitoring of treated water quality. Again, a recorder is not necessary but may be an individual preference.

Example Pipe Rack LayoutIn a corrosion control optimization study, it is desirable to have several pipe

racks, each with replicate test loops, run side by side to obtain comparisons of lead and/or copper levels under various treated water quality conditions. Figures 1.8 through 1.10 present schematic drawings for a complete pipe rack facility. This example facility was designed to evaluate four different treated water quality conditions and includes a control rack for a comparison of metals levels under existing water quality conditions. Each of the racks in this example contains three replicate lead-soldered copper test loops and a corrosion tester (CERL or other) for weight loss analyses.

The treated water quality conditions in the example include two different pH and alkalinity adjustments, orfliophosphate addition with a pH adjustment, and orthophosphate addition alone. With the control water quality condition, a total of five racks is running simultaneously.

The four treated water quality conditions can be created using three chemical feed tanks: a base feed tank, an alkalinity feed tank, and a tank for orthophosphate. Chemical feed lines could be drawn off the tanks for each of the treated water scenarios, as shown hi Figure 1.8. Each of the feed lines would contain a chemical feed pump along with a calibration tube. In Figure 1.8 a static mixer and a water heater have been placed downstream of the chemical injection point prior to the test loops on the influent line to the rack. Figure 1.9 displays a typical elevation view of one of the pipe racks as it might be constructed. An optional side stream for continuous water quality monitoring is shown hi this view. Finally, Figure 1.10 presents an example floor plan of the entire pipe rack installation to indicate how several racks may be incorporated into the same work area.

This example ismeant as aguide for incorporating the basic recommendations for the AWWARF pipe rack design into an overall corrosion study. Each utility will develop specific manifolds, test loops, and treatment systems for its individual corrosion optimization study. The equipment list for this particular example is presented in Table 1.3, along with cost estimates for materials. The cost estimates were based on actual estimates from several pipe rack studies. This table does not include materials costs for structural support of the racks, PVC piping and fittings, or miscellaneous benchtop laboratory equipment that may need to be purchased, hi addition, there will be labor costs for construction. These items would be specific to each utility's pipe rack operation; however, estimates are provided hi Table 1.4 as an indication of what the range of costs might be. These total costs translate to approximately $10,500 to $13,000 per rack. Two of the participating utilities in this study kept track of labor and materials costs for their racks, each of which consisted of three replicate test loops of soldered copper, no CERL tester, and no treatment equipment. These costs ranged from $3,900 to $4,000 per rack, figures that are in line

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COPPER PIPE LOOPS, Pb/Sn SOLDO?

COUPON TESTER

OPTIONAL SIDE STREAM FOR CONTINUOUS WATER QUALITY RECORDERS

I*

X

D u n//=*\

STATIC MIXER '

CHEMICAL FEED TUBING J

- OTHER CORROSION TESTING APPARATUS OR FUTURE TEST LOOP

- TOTALIZING FLOWUiTER

BASE FEED TANK

-SUPPLY AND DRAINS

Figure 1.9 Example elevation of pipe rack

PVC SUPPLY PIPING —i (FROM BELOW) \

PVC DRAIN PIPING TO SUMP (BELOW)

Figure 1.10 Example floor plan of pipe rack


Table 1.3 Example equipment list and costs for example pipe rack installation

Totals ($)ItemNumber of

unitsUnit

price ($)

FlowmetersRotameters 25Flowmeter (0-10 gpm) 5Flowmeter (0-50 gpm) 1Flowmeter sensor 6Flowmeter installation fitting 6

Chemical feed equipmentMetering pumps 7Storage tanks 3

Cover 3Stand 3Mixer 3

Static mixers 4PTFE tubing 9

Valves and controlsElliptic valve (% in.) 73-way elliptic valve (% in.) 7Ball valve (M> in.) 50Ball valve (1 in.) 10Ball valve (1M> in.) 3Sample cock valve (% in.) 26Ball check valve (% in.) 50Ball check valve (1 in.) 4Check valve (% in.) 4Pressure control valve (1 1/4 in.) 1Backflow preventer (1% in.) 1Microprocessor controller 1Solenoid valve (1 in.) 1Pressure gauge 6

Test loop materialsCorrosion testers (1/rack) 5Copper pipe loops (5 racks, 3 test loops/rack) 15

Total

70440440200

70

700350

55520200260

50

254020305010203060

37525

270260

60

1,000430

1,7502,200

4401,200

420

4,9001,050

1651,560

6001,040

450

175280

1,000300150260

1,000120240375

25270260360

5,0006,450

32,040

Note: This table does not contain costs for items such as PVC pipe and fittings, pipe clamps, structural equipment, and laboratory or benchtop water quality analysis equipment. Also, it does not contain equipment needed for the optional side stream for continuous water quality monitoring. These items will depend on the facility's layout and operational plan and are specific to each utility. Unit prices are estimates based on several utility pipe rack material costs ($1,992).

with the cost estimates for the example layout. Again, the reader should bear in mind that these estimates are meant to provide reasonable guidelines for total construction costs for a pipe rack layout similar to the one shown on Figure 1.8. Site constraints and individual study needs for each utility will dictate the actual costs that might be incurred by incorporating this AWWARF pipe rack into a corrosion control optimization study.


Table 1.4 Estimated costs for additional items involved in pipe rack construction

Item

Labor to construct test loops Structural support (labor and materials) Miscellaneous piping and fittings

(labor and materials) Laboratory equipment

Subtotal

Number of man-hours

160 120

40 NA

Estimated costs* ($)

$5,000-$7,000 $12,000-$1 8,000

$2,500-$5,000 $1,000-$4,000

$20,500-334,000

Equipment costs (from Table 1.3) NA ___$32.040

Total $52,540-$66,040

NA = not applicable * Assumes labor costs of $35/h to $50/h.

OperationPriorto initiating pipe rack operations, several data collection and operational

issues must be resolved, including• how long the pipe rack should be operated• what type of startup procedure should be used• what on-off cycling regime to incorporate, as well as the total

throughput volume to the loops• how chemical solution mixing will be accomplished• what water quality parameters should be measured, and at what

frequency• what procedures will be used for sample collection and analysis

The following section provides recommendations for each of these issues.

Pipe Rack Startup ProceduresThe National Association of CorrosionEngineers (NACE) recommends that

newly constructed plumbing systems be flushed thoroughly to remove debris and other contaminants from the system. Thus it is appropriate for test loops to be flushed as well. Like actual plumbing, soldered copper test loops may become contaminated by flux residue, which may be responsible for corrosion and metal dissolution. The flushing procedure is a standard plumbing practice and should be done while the system is being leak tested. Flushing water should come from the same source and be of the same quality that is anticipated to flow through the pipe rack test loops during the study. Incorporating a flushing procedure into the startup phase of the pipe rack study may tend to minimize the time required for metal dissolution rates to stabilize and approach equilibrium conditions.

Flushing guidelines for the test loops in the AWWARF pipe rack are as follows:


• Stepl. After fabrication and before placement in the AWWARF pipe rack, test loops of all materials should be flushed with cold (32 to 86°F [0 to 30°C]) water for 15 minutes at a water velocity of 5 to 10 fps (1.5 to 3.1 m/s); i.e., 4 to 8 gpm (0.26 to 0.51 L/s) for type L V£-ia (12.7-mm) copper tube. Leak testing and flushing water should come from the same source (i.e., control) to be used in the study. After this initial flush, proceed to step 2 or step 3.

• Step 2. (This step applies only to solder-jointed copper tube test loops. If test loops are fabricated from other materials, proceed to step 3.) Following the cold water flush, connect test loops to a hot water source (150 to 160°F [60 to 70°C]), adjust water velocity through the loops to between 0.5 and 1.0 fps (0.15 and 0.31 m/s) (0.4 to 0.8 gpm [0.026 to 0.051 L/s] for a ^-in. [12.7-mm] tube), and continue flushing with hot water for 4 days. Several soldered copper test loops may be connected in series to minimize hot water demand. If hot water is not available, cold water may be used; however, there may be less reduction in metals levels as a consequence. When flushing has been completed, install test loops in the AWWARF pipe rack, pressurize the system, and set a programmable timer to regulate water flow. Initiate a corrosion study without delay. Loops could also be flushed after installation in the pipe rack.

• Step 3. (This step applies to lead tube, unjointed copper tube, and test loops of other materials.) Following the step 1 cold water flush, install test loops in the AWWARF pipe rack, pressurize the system, and set a programmable timer to regulate water flow. Initiate a corrosion study without delay.

After the test loops and pipe rack system have been pressurized, the water should not be static for more than 24 hours. Chlorine residuals in copper plumbing can disappear within 4 to 6 hours. Although chlorine residuals may decline less rapidlyinotherplumbing materials, microorganisms can develop underlengthy static conditions in the pipe rack. Once developed, the microorganisms are difficult to control and may interfere with the corrosion processes.

Determining Equivalence of Pipe RacksPrior to introducing the various treated water qualities to the pipe racks, it

may be desirable to establish that the control rack and the treatment racks produce similar standing metals levels. This verification provides assurance that all pipe racks were constructed in a similar fashion and provides similar starting points for evaluating treatment effects on metals leaching. This checking can be accomplished by running control water through all of the pipe racks under standard flow conditions and on-off cycling (see recommendations below) and collecting a series of standing samples to compare. This preconditioning procedure was not evaluated as part of this study, but the concept evolved after preliminary evaluation of the pipe rack data and has been used successfully in other studies.

In treatment evaluation studies, the effectiveness of a particular treatment will be compared against a control condition or another treated water quality condition. Running control water through all racks and comparing the metals levels from each will provide information to support or refute the assumption that all test


loops were constructed similarly. If results from this initial phase of sampling are unacceptable, a decision can be made to reconstruct or drop those test loops from the study. Metals levels need not have stabilized to make this comparison. If the metals levels were detennined to be similar across the racks, treated water could then be introduced and normal corrosion testing operations begun. Although this study did not provide data to recommend this mode of operation, it is suggested that this approach be used for 3 to 4 weeks to condition the pipe material.

Normal Corrosion Testing OperationStanding Time and Control of Flow Through the Pipe Rack. The pipe

racks operated during this study incorporated two differentflow regimes. Four of the utilities incorporated a daily on-off cycle with one 8-hour standing period each day, which resulted in a total throughput volume of approximately 200 gpd (0.76 m3/d), or 1,470 gal/week (5.32 m3/week).This amount is similar to usage inatypical single- family dwelling. The two utilities mat evaluated the impacts of various treatments on lead and copper levels both implemented a continuous-flow regime. Water was allowed to flow through the racks continuously for 1 week and was then shut off for a 16- to 24-hour standing time prior to sample collection. The total throughput volume under this operating scenario was approximately 1,234 gpd (4.67 m3/d), or 8,640 gal/week (32.7 m3/week).

Daily on-off cycling more closely simulates water usage by a typical household; i.e., between 10 gpd (0.44 L/s) from a single faucet and 210 gpd (9.2 L/s) for an entire house. If the flow conditions in a house can be simulated, presumably the corrosion conditions in home plumbing can also be more closely modeled, although side-by-side comparisons of the two regimes were not made. On the other hand, the continuous-flow regime appears to provide several advantages over a daily on-off flow cycle. Less operatortime is needed if the shutoff valves must be manually operated, and it may be easier to maintain consistent treated water quality conditions. The cost of treatment appurtenances may also be lower, however, more water may be wasted, depending on the application, and chemical costs may be higher. Although cost and ease of operation are important factors in pipe rack operations, more closely simulating the corrosion processes that would take place in consumer plumbing would eliminate a variable from the test procedures and should be given priority when making decisions about flow regime. For this reason, a daily on-off cycling regime is recommended for the AWWARF pipe rack. The use of a standardized flow regime by utilities constructing the AWWARF pipe rack will also allow comparisons of metals levels collected under equivalent physical conditions among other utilities.

The following on-off operation will provide adaily 8-hour standing time and a total throughput volume of 180 to 210 gpd (7.89 to 9.20 L/s) at a flow rate of 1 gpm/loop (0.063 L/sAoop):

Time Cycle mode7:30 a.m. on8:30 a.m. off4:30 p.m. on5:00p.m. off7:30 p.m. on8:00p.m. off


10:30 p.m. onll:00p.m. off1:30 a.m. on2:00 a.m. off4:30 am. on5:00 a.m. off

The 1 -gpm (0.63 L/s) flow rate was recommended in the original AWWARF pipe rack design study and was incorporated by all of the utilities in this study without problems. Given the recommended test loop dimensions, this flow rate will provide a flow velocity high enough to avoid accumulation of paniculate matter without exceeding maximum velocity guidelines for preventing pipe erosion.

Water Quality Sampling and Frequency of Sampling. Parameters recommended for water quality sampling from the pipe rack are divided into two major categories:

1. standing samples, for corrosion-related parameters2. running samples, for influent water quality characteristics and

operational consistencyWater quality results from standing samples will provide data on metals

leaching as well as information on general corrosion processes. Although each utility should develop its own study-specific water quality monitoring plan, the following list of parameters is recommended as a minimum for analysis from first-flush standing-water-quality samples:

leadcoppertemperaturealkalinitytotal and free chlorinepH

Samples should be collected by slowly opening the sample valve and allowing the first 35 mL to drain off. Water temperature, pH, and conductivity should be analyzed from the first sample collected from each loop on site. This practice assures that the valve has been flushed of any water and that the following samples for metals levels will have been in direct contact with the test loop material. Chlorine residual, temperature, and pH should be measured immediately after sampling, and the pH sample should be collected in closed containers with no air space in order to avoid pH drift.

The frequency with which standing samples are collected should be based on the expected variability of the results and the availability of staff and laboratory resources. Appendix C contains background information for estimating the required number of samples based on the expected variability of the samples and the desired confidence in and accuracy of the results. The metals levels measured from the pipe racks in this study exhibited highly variable lead and copper levels, with ratios of the standard deviation to the mean of 1:1 or 1:2. Using these ratios as a guideline, Table 1.5 shows the numbers of metals samples that would need to be taken for various confidence and accuracy levels.


Table 1.5 Numbers of metals samples needed for various confidence intervals and accuracy levels______________________________________

Ratio of standard deviation to mean

1:2 1:1

Accuracy level

25 percent20 percent15 percent10 percent

90 percent confidence

interval11*17*3068


interval16*25*4397


interval

4468

121271


interval

6297

171385

* It is recommended that a minimum of 30 samples be collected if possible, for statistical reasons.

As an example, a total of 121 lead samples would need to be taken from the pipe rack for each water quality condition inorder to reach 90 percent confidence that the mean lead level measured falls within ±15 percent of the actual population mean. This total would translate to one sample being taken every 10 days from each of three replicate test loops over a 52-week period. However, because metals levels may not stabilize for 5 to 8 months, the number of useful samples may be restricted to the final 16- to 20-week time period for a year-long study. For a 16-week time period, the sampling frequency required to achieve the same accuracy and confidence level would be one sample taken every 3 days from each of the three replicate loops.

Running samples should show the water quality characteristics of the source water both before and after it is treated, as well as provide information on the accuracy of the chemical feed system. Background water quality samples should be taken during the flow period immediately before the standing time, after water has been flowing through the rackfor aminimum of 30 minutes, and as close tothe shutoff time as is practical. The following parameters are recommended for collection from running influent samples to provide information on incoming water quality in all of the racks and to allow for interpretation of the metals levels measured from standing samples:

• pH• ammonia• alkalinity• dissolved oxygen• orthophosphate• conductivity or total dissolved solids (TDS)• heterotrophic plate count• temperature• free and total chlorine• lead• copper• calcium• iron• color• total coliforms


The consistency of the source water will play a significant role in determining how frequently these parameters should be measured. Treatment interruptions or other events that may radically change incoming water quality may not be documented if these parameters are sampled on amonthly basis; therefore, weekly sampling may be prudent.

Running samples should also be collected after the various treatment trains to evaluate the consistency of the treated water. Depending on the treatment, the chemical feed system canbe monitored by evaluating pH and alkalinity, concentration ofinhibitor.calcium.and disinfectant residual. These parameters shouldbe monitored every day if possible. In-line, continuous water quality monitoring of pH and alkalinity can be used but may add an element of complexity.

Thorough records of the mechanical operating conditions should also be maintained, including flow, pressure, and throughput volume. These records will provide day-by-day input on the physical operation of the racks as well as valuable information during the data interpretation phase.

Length of Study. The total length of the pipe rack study must be deter mined by

• the time required to maintain stable metals levels• the number of samples needed to achieve desired accuracy and

confidence in the data resultsBased on the results of several pipe rack operations, it can take from 3 to 9

months for lead levels to stabilize in either lead loops or lead-soldered copper loops. Copper levels may stabilize in a shorter period, 2 to 8 months. The utilities participating in this study all operated their pipe racks for 12 months. Several of the pipe rack results indicated that metals levels were still declining after 1 year. In addition, seasonal water quality changes may have impacted metals leaching, but these impacts couldnotbe determined over only 1 yearof operation. Althoughutilities may need to incorporate results from their pipe rack study into an overall corrosion control optimization study after 1 year of operation, they are strongly encouraged to extend the operation of their racks to provide continuing information on the effectiveness of treatment and allow utilities to continue to optimize for corrosion control. In addition, long-term pipe rack operation will provide data on the leaching of lead and copper from the pipe rack materials as they age and allow the influence of seasonal water quality changes to be more accurately assessed.

Avoiding Pitfalls in Pipe Rack Design and OperationThis section summarizes specific recommendations for avoiding problems

that can occur with pipe rack operations. Pitfalls in pipe rack operation can be minimized through good planning, design, fabrication oversight and coordination, and quality control during operation. The following checklists give summaries of items and considerations for avoiding pitfalls.


Design• Ensure that the detailed design meets all requirements of the pilot

study objectives and the sampling and testing plan.• Ensure that any bid design drawings and specifications leave no room

for misinterpretation by fabricators.• Ensure that adequate plant water drainage, power, lighting, heating,

and ventilation are available at the pilot plant site.• Thoroughly mix chemicals in their vats before use and ensure that

precipitation does not occur in storage vessels. Lime can be a significant problem in this regard.

• Include devices for good mixing of chemical feed solutions with ambient water on all racks (e.g., static mixers, adequate run-of-pipe, etc.).

• Include air vents or sample ports near the highest hydraulic points in the pipe rack to allow for venting of air pockets.

• Include an appropriately sized pressure-reducing valve on the influent side of the racks; rack pressure should be compatible with chemical pump delivery pressures.

• Include enough sample ports throughout the racks to allow for all required or possible sample collections.

Fabrication• Provide for good supervision or oversight of the pipe rack fabrication

process.• Have the same qualified plumber solder all pipe joints in lead-

soldered copper pipe loops to ensure consistency in the amount of solder and flux used.

• Have the fabricator document the amount of solder used in each pipe loop.

• Avoid excessive flux deposits on the interiors of soldered pipe loops.• Leak-test all of the pipe loops.• Ensure that proper shop cleaning of pipe loops is performed.• Ensure careful handling if shipping of finished pipe racks is required.

Startup and Operation• Provide for adequate flushing or preconditioning of pipe loops prior

to starting operations.• Ensure that all operators are trained in specific operating and

sampling procedures.• Provide for consistent control and monitoring of pipe rack operations.• Disinfect sample ports to preclude high bacteria counts in initial

water samples.• Ensure that excessive pressure drops across the pressure-regulating

valve do not occur, as air bubbles in the pipe rack may result, causing flow disruption.

• Ensure that the pilot plant site temperature remains above the freezing point of the chemical solutions being used.


Keep chemical solution tanks covered to reduce evaporation andresulting changes in solution concentrations.Ensure that chemical feed systems are operating properly.

Recommendations for Statistical Evaluation of Corrosion Control Study Data_____________

This section provides recommendations for evaluating the data generated during apipe rack study. This evaluation should include the following key components:

• determination of data normality• evaluation of data outliers• determination of when lead and copper levels have stabilized during

the corrosion study• determination of treatment differences

The data evaluation phase of a pipe rack study is critical to correctly interpreting the results and providing a sound statistical basis fortreatment decisions. The following section presents guidelines for a recommended data analysis sequence that can be applied to pipe rack results.

Determining Data NormalityWhen evaluating lead and copper level data from a corrosion study, it is

important first to assess the distribution of the data that have been collected in order to apply the correct statistical tests. For data not normally distributed or for which the distribution is unknown, nonparametric tests should be applied. Data distributions can be determined using graphical techniques such as histograms, where the y axis represents the frequency of occurrence of a given variable and the x axis represents the values of the variable. Appendix C presents additional graphical techniques for determining frequency distributions. Computer statistical packages may also be used, and they offer the added advantage of providing the statistical significance of the underlying distributions in addition to graphical representations.

Evaluation of Data OutliersAfter reviewing the distribution of the data generated from a corrosion study,

itmay seem appropriate todiscard several of the very high levels as outliers, or values that are anomalous. When these values are discarded, the mean level of the data will be lowered and there will be less variation in the data. Discarding very high lead values may seem particularly attractive when the difference between lead levels from acontrol pipe rack and those from treated pipe racks is being measured. It is important to note, however, that lead levels measured at the tap in the distribution system also are occasionally found to be high. The occurrence of what appear to be unusually high lead levels in home tap samples is evidence of the chemical and physical factors that impact the amount of lead that may enter the water. These factors are also present in pipe loop studies, although an attempt has been made to reduce the variability of lead measurements by controlling these factors to the extent possible. These apparently


high lead levels may occur at various times during the pipe loop study period and in many cases cannot be attributed to sampling or analytical error. Rather, they reflect the highly variable nature of lead corrosion and solubility.

In summary, occasional high lead levels may be measured during corrosion studies as well as during home tap sampling. It is recommended that high lead and copper levels from pipe rack studies only be discarded as outliers if there is documented evidence that the sampling or analytical technique for those particular samples was in error. Otherwise, the levels should be considered "real" values and incorporated into the entire data set

Tests for StabilizationPipe loops constructed of new materials and used for corrosion studies of

lead and copper leaching will exhibit a decreasing trend in lead and/or copper levels overtime as the materials age. These levels may stabilize after acertain period of time if the incoming water quality is relatively consistent, as was seen in Figures 1.3 and 1.4. This stabilization may indicate that the pipe materials have reached equilibrium with respect to corrosion or have reached a state where film formation has become very slow. Although it may be of interest to evaluate the entire set of data generated from a pipe rack study, it is more appropriate to use only data that have reached stabilization when determining the impact of various treatments on lead and copper levels. Stabilization can be determined roughly by visual examination of the data or more specifically through calculating an estimated trend line for the data. Visual examination is liable to be less sensitive to slow changes than are numerical techniques and may be less likely to determine the impact of the variability of the data. The most common numerical method for determining trends is application of a best- fit line to the data. A linear trend line is described by the following formula:

Y = aX + b

where a is the slope of the line and b is the intercept. If the trend line has a negative slope, the values are estimated to be decreasing with time. If the line is positive, the values are estimated to be increasing with time. The more negative or positive the slope of the estimated line, the more pronounced is the trend. Very flat estimated trend lines (a=0) have essentially stabilized.

For parametric data, the Pearson correlation coefficient can be used to determine how close the actual observations (y) are to values estimated by the trend line (y*). Correlation coefficient (r) values of-1 denote aperfect negative correlation, and rvalues of+1 indicate aperfect positive correlation. The correlation coefficient (r) is the positive or negative square root of the coefficient of determination (r2). Coefficient of determination values of zero indicate that the equation explains none of the variation in y, whereas values of 1 mean that all of the variation is explained; i.e., all y values lie on the regression line.

For nonparametric data, the Spearman rank correlation coefficient may be used rather than the Pearson correlation coefficient The Spearman r is the correlation coefficient applied to rank orderdata, and it ranges from-1.0 to+1.0. Positive values approaching 1 indicate that increases in one variable are accompanied by increases


in the other variable. Negative values near -1 indicate the opposite. With the Spearman r, it is important to note that the r values are calculated on the rank order of the values rather than on the values themselves.

It is important to evaluate the trend in metals levels as the pipe rack study progresses. If levels have begun to stabilize, as determined by evaluating a trend line and correlation coefficient, a decision can be made as to how many more samples will be needed to substantiate the treatment differences.

Determining Treatment DifferencesThe ultimate goal of a pipe rack study is to determine whether a particular

treated waterqualityconditionresultsinleadorcopperlevels significantly lowerthan those in the control water. Incorporating statistical tests in these determinations provides additional information on the extent and the statistical significance of the difference. Commonly usedmethods to compare differences between populations are the t test forparametric data and the Wilcoxon test for nonparametric data. The mean and standard deviation of the data are used in parametric methods, and percentiles are used hi the nonparametric methods. Metals levels from the pipe rack studies discussed in Chapter4 exhibited nonnormal data distributions with very few data points in some cases, and therefore nonparametric Wilcoxon test methods were employed when the data were evaluated.

Once lead or copper levels have stabilized, these methods can be used to determine differences in metals levels due to various treatments. The significance levels of these differences (r level or p level) can be calculated and will provide information on the level of confidence to expect from the results. A significance level of 95 percent (r = .05) is generally considered highly significant; i.e., there is a 95 percent chance the right decision has been made. In addition, using aggregate data from all three test loops will provide information on the variability observed in lead levels between the control and the various treatments and will also allowadetermination of the degree of confidence that can be assigned to the results. An example of determining treatment differences is presented below, using data from New York City's Catskill Delaware lead loop results.

In the Catskill Delaware lead loops, the control loop stabilized after approximately 279 days of operation. Loop 5, which was treated with zinc orthophosphate, stabilized after approximately 230 days. Using the Wilcoxon signed rank test to compare these two treatments first involves developing anull hypothesis, which will be either accepted or rejected based on the results of the test. In this case, the null hypothesis is that there is no difference between these two water quality conditions; i.e., there is not enough difference in lead levels of the two water quality conditions to say with a certain amount of confidence that Ihe treatment was effective.

The Wilcoxon signed rank test is performed by ranking the difference between matched pairs of data from each of the two loops, summing the positive ranks (T*), and calculating a Z value, which is then compared to the critical a for a 95 percent confidence. If the Z value falls outside the critical region, the null hypothesis is rejected; i.e., the treatment is judged effective.

In comparing the control loop with Loop 5 (zinc orthophosphate), data from day 279 and later are used, and the Wilcoxon signed rank test is accomplished as showninTable 1.6. The value 1.99 calculated from the Wilcoxon test is greater than

1.645 (the critical region for 95 percent confidence). Therefore the null hypothesis is rejected at the 95 percent confidence level; i.e., the treatment is judged effective. However, with data from only one loop, the variability of the lead levels exhibited by the control and the treated water quality conditions cannot be determined; i.e., there is less certainty in the difference than if replicate loops had been included for each condition.

This difference in treatment effectiveness can be displayed visually through the use of box and whiskers plots. Figure 1.11 is abox and whiskers plot of lead levels from the control loop and Loop 5. The mean lead level in Loop 5 is obviously much lower than in the control, and the standard error about the mean for Loop 5 is well below that of the control.

This procedure can also be used to determine if one treatment is more effective than another. Comparing lead Loop 6 (zinc orthophosphate) with lead Loop 8 (blended orthophosphate) lead levels produced the results shown hi Table 1.7. Because the Z level is less than 1.645, the null hypothesis is accepted at the 95 percent confidence level; i .e., there is judged to be no difference between the treatments. This result can be seen in the box and whiskers plot hi Rgure 1.12, in which the data characteristics of both loops appear to be essentially similar, i.e., there is no difference between them.

Table 1.6 Wilcoxon signed rank test for Loop 5 and control loopControl loopxi

1.221.121.520.581.470.82

R, = rank of Z,S = 1ifZ,>0S = OifZ,<0

LoopSy.

0.341.170.430.220.350.45

*! = x, - Vi

0.88-0.05

1.090.361.120.37

R,

415263

S*

101111

R,(S)405263

20

T* - n(n + 1)_____4

I n(n + 1X2n H N 24

where n = number of samples = 6

I 6(7X13) 24

2.20


16r.

*— H

T3

S

43.5

32.5

21.5

10.5

0-0.5

.1

.---•-••--

I \

3?

• Mean

c=3 2 StandardError

T 2 StandardDeviation

Control Loop 5Figure 1.11 Box and whiskers plot of lead levels, control and Loop 5, days 230 through 322

Table 1.7 Comparison of lead levels in Loops 6 and 8Loop 6 lead level

0.110.0830.0710.0230.0360.025

LoopS lead level

0.0810.0230.0720.850.0240.044

z,0.0290.060

-0.001-0.062

0.012-0.019

R,451623

S

110010

R,(S)450020

11

T* = 4 + 5 + 2 = 11 Z = .105

4.5

4 3.5

3H. 2.5

<u

0.5

0-0.5

-1

a 2 Standard Error

T 2 Standard Deviation

Loop 6 Loop 8Figure 1.12 Box and whiskers plot of lead levels, Loops 6 and 8, days 230 through 322

Chapter 2___________

Introduction and BackgroundPurpose

The Safe Drinking Water Act (SDWA), PL93-523, was passed by Congress in 1974. This act authorized the USEPA to develop national regulations for health- related contaminants in drinking water as well as for the overall aesthetics of drinking water. This requirement led toarevisedstandardfor lead and copper in drinking water to reduce the public's exposure to these metals. The Final Maximum Contaminant Level Goals and National Primary Drinking Water Regulations for Lead and Copper in Drinking Water (final Lead and CopperRule) was published by the USEPA in June 1991 (USEPA 1991). The regulation established tap monitoring requirements for assessing the levels of lead and copper in distribution system, service lines, and premise piping systems and presented a regulatory process for reducing the levels of these metals, if necessary, through the application of various treatment techniques.

The objective of this project was to develop a standard protocol for use of the AWWARF pipe rack. This pipe rack provides utilities with a tool for evaluating the effectiveness of various treatment options in controlling lead and copper levels in distribution system tap samples. The AWWARF pipe rack was originally designed and tested as part of an earlier study funded by the research foundation, the lead control strategies manual project (EES1990). This book is an extension of that earlier work and provides a more detailed examination of the use of the pipe rack by several utilities as well as information on the pipe rack's usefulness in determining adequate treatment for reducing lead and copper levels. This study is relevant because utilities often need to test watertreatment options in apilot plant before they go full scale, due to public health and cost implications.

The following chapters describe the construction and operation of the AWWARF pipe rack by several participating utilities and present conclusions that resulted from these studies. These conclusions were used to develop a recommended protocol, which was presented in Chapter 1. This chapter provides background information on regulations governing lead and copper in drinking water, discusses past pipe loop studies that have evaluated corrosion of lead and copper, and describes each of the study participants. Chapters 3 and 4 present the specific methods and materials used by each of the utilities in constructing and operating the AWWARF pipe rack at their facilities and provide an evaluation of the pipe rack operation and results, including a summary of the major findings.

39


Regulatory Background

This section provides a summary of the federal drinking water regulations that should be considered when using the AWWARF pipe rack. These regulations include the final Lead and Copper Rule (June 7,1991), the Lead Contamination Control Act (October 31,1988), the Surface Water Treatment Rule (December 31, 1991), the Total ColiformRule(December31,1990), and theupcoming Disinfection/ Disinfection By-Products Rule.

Final Lead and Copper RuleThe USEPA published the final Lead and Copper Rule on June 7,1991. This

rule established maximum contaminant level goals (MCLGs) and action levels for lead and copper in tap water samples, set forth monitoring requirements for at-the- tap samples of lead and copper, and specified corrosion control treatment requirements. The MCLGs and action levels established for lead and copper are as follows:

Contaminant MCLG ' Action level

Lead 0 0.015 mg/L measured in the 90th percentile oftap samples

Copper 1.3 mg/L 1.3 mg/L measured in the 90th percentile oftap samples

The treatment requirement presented in the final Lead and Copper Rule is triggered when a utility exceeds the action levels for lead or copper, in which case the utility may be required to take one or more of the following actions:

• Install optimal corrosion control treatment.• Install source water treatment.• Implement public education.• Initiate lead service line replacement

The evaluation and implementation of optimal corrosion control treatment has a direct impact on use of the AWW ARF pipe rack. The following sections describe the monitoring, public education, and corrosion treatment evaluation requirements of the final Lead and Copper Rule.

Monitoring RequirementsWater systems must monitor for lead and copper every 6 months at

consumers' kitchen taps. The number of sites required to be sampled during each 6-month period is dependent on the population served, as presented in the following:

Introduction and Background 41

Population served Number of sites/6 months

>100,000 10010,001-100,000 603,301-10,000 40

501-3,300 20101-500 10

<100 5

Tap monitoring sites were to be identified and initial monitoring completed by the following dates:

• January through June 1992 for systems serving more than 50,000 people

• July through December 1992 for systems serving between 3,301 and 50,000 people

• July through December 1993 for systems serving 3,300 people or less

Utilities must collect samples from the cold water kitchen tap after the water has been standing in the interior plumbing for a minimum of 6 hours. These samples are then analyzed for lead and copper levels. Samples must be taken from targeted monitoring sites (i.e., lead service lines or copper plumbing from new homes where lead solder was used). Prior to initiating a monitoring program to evaluate corrosion, the utility must complete a materials survey to identify these targeted high-risk residences. The regulation established three tiers foridentifying potential monitoring sites. The firsttier is composed of single-family residential houses withlead-soldered copperplumbing that was installed after 1982 orthat includes alead service line. The utility must try to draw all of its sampling sites from this first tier. If enough sites cannot be found within tier 1, then tier 2 sites can be used. Tier 2 sites are buildings or multif amily residences with the same plumbing characteristics as the houses in tier 1. If the required number of sampling sites still cannot be located within these tiers, the utility can use tier 3 sites, which are single-family residences with lead-soldered copperplumbing installed before 1983.

In addition to the tap sampling for lead and copper, other water quality parameters may need to be sampled from the distribution system and entry points to the distribution system every 6 months. These parameters are

pHalkalinitycalciumconductivitytemperatureorthophosphate or silica (if inhibitors are being used)

All water systems serving over 50,000 people must implement monitoring for these other water quality parameters. Smaller utilities would need to initiate this monitoring only if the action levels for lead and/or copper were exceeded at the tap. The number of sites required to be sampled is also based on population served, as follows:

System size Number of sites/6 months

>100,000 2510,001-100,000 103,301-10,000 3

501-3,300 2101-500 1

<100 1

Public Notification and Education RequirementsPublic water systems must initiate a public notification and education

program if they fail to meet the action levels for lead at the tap. The final Lead and Copper Rule contains language that must be used for the public notification. The public notification and education program should provide information on the sources of lead in the environment, potential health risks associated with lead, and actions consumers can take to reduce their exposure to lead in drinking water.

Corrosion Control Study RequirementsAll large water systems serving more than 50,000 people are required to

conduct corrosion control studies. Small and medium-size utilities (serving 50,000 people or fewer) must submit a recommended approach for optimal corrosion control treatment to their state agency for approval if monitoring has indicated that lead and/or copper have exceeded the action levels. These studies could consist of evaluations of various treatment approaches using pipe racks or of documentation of corrosion control treatments implemented by utilities with similar water qualities.

The USEPA published a guidance manual forthe final Lead and Copper Rule (USEPA1992) that provides a step-by-step framework for conducting a corrosion study, as follows:

1. Documenthistorical evidence.2. Evaluate source water contribution.3. Identify constraints.4. Identify corrosion control treatment priorities.5. Eliminate unsuitable approaches based on findings from steps 1

through 4.6. Evaluate viable alternative treatment approaches.7. Decide whetherto conduct demonstration testing.8. Perform corrosion control demonstration testing.9. Make preliminary cost estimates and facility modifications.

10. Recommend corrosion control treatment.


State regulatory agencies will either approve a utility's recommended treatment approach or designate an alternative treatment Utilities will have 2 years to institute the treatment and must conduct follow-up sampling within 12months after the treatment is put in place. Finally, the primacy states will establish operational levels for the following water quality parameters:

pHalkalinitycalcium, if carbonate stabilization is usedorthophosphate, if a phosphate-containing inhibitor is usedsilica, if a silicate inhibitor is used

The levels established will constitute "optimal" corrosion control treatment and utilities must operate their systems within these conditions. The definition of optimal treatment is corrosion control that minimizes lead and copper levels at users' taps while ensuring that the treatment does not cause the water system to violate any national primary drinking water regulations.

When evaluating and implementing corrosion control treatment, utilities must carefully consider the effects a particular treatment may have on the efficiency of other treatment processes, distribution system water quality, and the potential impacts on various industrial and municipal water uses. There are several potential secondary and tertiary effects of lead treatment, including

effects on optimal coagulationincreases or decreases in disinfection efficiencyeffects on chemical oxidationincreases in disinfection by-product formationchanges in calcium carbonate stabilityimpacts on corrosion of other materialsprecipitation of zinc, causing filter clogging and customer complaintstaste and odor problemsbacterial regrowthimpacts on wastewater facilities such as elevated phosphate levels inwastewater effluents and elevated zinc levels in wastewater treatmentplant sludges

The use of controlled simulated plumbing systems, i.e., pipe racks, to evaluate corrosion treatments can be an important methodology for determining optimum reductions in lead and copperlevels and for assessing the secondary impacts of a treatment on a system's overall water quality and regulatory compliance. The AWWARF pipe rack was specifically designed to address these issues.

Various corrosion control treatments can also directly impact a utility's ability to comply with federal Safe Drinking Water Regulations, several of which are described in more detail below. The flexibility to evaluate these impacts under controlled conditions before implementing full-scale treatment is highly desirable.


Related Federal RegulationsLead Contamination Control Act

On November 1,1988, the Lead Contamination Control Act (LCCA) was passed into law. This law was created to help reduce the public's exposure to lead in drinking water, particularly exposure of children. Previously, as part of the 1986 amendments to the SOW A, the USEPA had banned the use of solder containing more than 0.2 percent lead, and pipes and pipe fittings with more than 8 percent lead, in public watersystems. The LCCA addressed the manufacture and use of water coolers with lead-lined tanks or other parts containing lead. It established penalties for the manufacture and sale of water coolers containing lead and required the USEPA to assist states and local entities in testing for and reducing lead contamination in schools and day care centers. The LCCA also included amandate for the Consumer Products Safety Commission to recall water coolers identified by the USEPA as containing lead-lined tanks. The USEPA published a proposed list of these coolers in the April 10,1989, Federal Register (54 FR 14320).

Surface Water Treatment RuleThe USEPA finalized the Surface Water Treatment Rule (S WTR) in June

1989. The SWTR specified filtration and disinfection performance criteria for all treatment facilities using surface waters, whether or not they currently employed filtration. This rule established criteria for systems to remain unfiltered and guidance for applying filtration and disinfection to control viruses, Giardia lamblia, and Legionella.

The performance criteria in the SWTR require that treatment must achieve 99.9 percent inactivation (3-log removal) of Giardia cysts and 99.99 percent inactivation (4-log removal) of viruses. Performance-level credit is given for inactivation for both filtration and disinfection. Filtered systems would be given creditforacertain amount of inactivationdepending on the filtrationtechnology, with the remainder of the inactivation requirements accomplished through disinfection. For systems wishing to remain unfiltered, this total reduction would have to be accomplished with disinfection alone. The exact disinfection credit awarded to a treatment facility is a function of the calculated CT value(s) for that system, where CT is defined as the residual disinfectant concentration (C, inmg/L) times the contact time (T, in minutes). The required CT values listed in the SWTR are dependent on pH and temperature. In general, for chlorine, the CT value required to achieve inactivation of Giardia and viruses becomes larger as the pH is increased because the disinfection efficiency of free chlorine is reduced when pH is increased. However, increasing pH may be an effective corrosion control treatment method for reducing lead leaching for some utilities. In order to achieve the same disinfection inactivation at a higher pH, these systems may have to use more chlorine or increase the contact time in order to meet a higher CT requirement.

Total Coliform RuleThe final Total Coliform Rule was published in June 1989 and sets maximum

contaminant levels (MCLs) based on the presence or absence of total coliforms in the distribution system. Systems that analyze fewer than 40 samples per month canhave


no more than 1 coliform-positive sample per month. For systems that analyze 40 or more samples per month, no more than 5 percent of the samples can be conform positive.

If total coliforms are detected in any repeat sample, the system must collect another set of repeat samples from the same location. Any routine or repeat sample that is total coliform positive must be analyzed to determine if fecal coliforms or Escherichia coli are present Any repeat sample containing fecal coliforms or E. coli would be a violation of the MCL for total coliforms.

The focus of this rule is to maintain an adequate level of disinfection throughout the distribution system in order to protect against bacterial regrowth and cross-connection contamination. Pipe rack evaluations of various corrosion control treatments could be extremely valuable in assessing the potential impact of a treatment on microbiological quality.

Disinfection/Disinfection By-Products RuleThe USEPA is preparing a Disinfection/Disinfection By-Products Rule

(D/DBP Rule). Disinfection of natural waters may result hi the formation of disinfectionby-products (DBPs). The concentration of DBPs depends on disinfectant dose, DBPprecursor concentration, pH, temperature, presence of other disinfectant- demanding materials, contact time, and other parameters. The primary DBPs that have been identified, such as THMs, are related to the use of chlorine. Total THMs are currently regulated by the USEPA at 100 ug/L. Individual disinfectants (i.e., chlorine, chlorine dioxide, and chloramines) as well as their by-products (haloacetic acids, chloral hydrate, bromate, chlorate, and chlorite) will most likely be regulated in the D/DBP rule, and the current standard forTHMs may be significantly reduced. THM formation increases with increasing pH, and therefore any corrosion control treatment involving pH adjustment should be evaluated for its impact on the formation of disinfection by-products; pipe rack studies in general could be used to evaluate changes in DBF concentrations caused by various corrosion treatments.

SummaryThe major regulation related to evaluating corrosion control treatment is the

final Lead and Copper Rule; however, several other regulations will also have a significant impact on a utility's evaluation of what constitutes optimal corrosion treatmentforits system. These rules include the SWTR, the Total Coliform Rule, the current THM regulation, and the upcoming Disinfection/Disinfection By-Products regulations. Treatment for lead reduction must be evaluated based not only on effectiveness of lead control, but also on the potential impacts of the treatment on these regulatory issues and other water quality parameters. Table 2.1 presents a list of corrosion control treatments and the impact they may have on other regulatory and water quality issues. Controlled pipe rack studies can assistutilities in this evaluation and provide the information necessary for selectinn of a corrosion control treatment that will optimize the overall quality of the water provided to consumers.

Tabl

e 2.1

In

terre

latio

nshi

ps o

f cor

rosi

on c

ontro

l tre

atm

ents

for l

ead

and

copp

er w

ith o

ther

regu

lato

ry a

nd w

ater

qua

lity

issu

esC

orro

sion

con

trol

SWTR

tre

atm

ent f

or

filtra

tion

and

lead

and

cop

per

disi

nfec

tion

Incr

ease

pH

Pote

ntia

lly re

sults

in

lowe

r disi

nfec

tion

effic

ienc

y.

Dis

infe

ctio

n by

-pro

duct

s

Incr

ease

d TH

M

form

atio

n.

Bac

terio

logi

cal

qual

ity;

Iron

Tota

l Col

fform

Rul

e an

d m

anga

nese

Cor

rosi

on

and/

or s

calin

g

Alka

linity

ad

just

men

ts

Requ

ires

high

er C

Ts

for

chlo

rine.

Requ

ires

high

er C

Ts

for

ozon

e.

Use

of c

oagu

lant

s at

hi

gher

pH

leve

ls m

ay

incr

ease

resid

ual

alum

inum

co

ncen

tratio

ns.

Poss

ible

incr

ease

in

disin

fect

ant d

osag

es

will

incr

ease

pot

entia

l fo

rmat

ion

of s

ome

DBPs

and

dec

reas

e po

tent

ial f

or o

ther

s.

Coul

d ch

ange

form

of

chlo

rine

from

HO

CI to

O

Ch, t

here

by lo

werin

g di

sinfe

ctio

n ef

ficie

ncy.

Pote

ntia

lly c

ould

cau

se

bact

eria

l qua

lity to

de

grad

e.

Incr

ease

d po

tent

ial f

or

prec

ipita

tion

of ir

on a

nd

man

gane

se a

t hig

her

pH le

vels.

Coag

ulan

t che

mica

l do

sage

may

nee

d to

be

adju

sted

to a

chie

ve

optim

al p

H.

Bica

rbon

ate

or c

arbo

nate

ad

ditio

n wi

ll in

crea

se

ozon

e ha

lf-life

, i.e

., di

sinfe

ctio

n wi

ll be

mor

e ef

ficie

nt.

Can

redu

ce c

orro

sivity

of

wat

er to

ward

som

e m

ater

ials.

Resu

lts in

slo

wer r

ate

of

unifo

rm c

oppe

r co

rrosio

n.Ca

n he

lp re

duce

pitt

ing

corro

sion

of c

oppe

r pip

e.

May

dec

reas

e co

rrosio

n ra

te o

f gal

vani

zed

pipe

.

May

incr

ease

or d

ecre

ase

corro

sion

of fe

rrous

m

ater

ials.

May

incr

ease

sca

ling

in wa

ters

hig

h in

calci

um.

Alka

linity

add

ition

coul

d ca

use

incr

ease

d sc

alin

g by

cal

cium

car

bona

te.

Can

redu

ce ir

on

corro

sion

rate

s. (con

tinue

s)

Tabl

e 2.1

(c

ontin

ued)

Corr

osio

n co

ntro

l tre

atm

ent f

or

lead

and

cop

per

SWTR

filtra

tion

and

disi

nfec

tion

Disi

nfec

tion

by-p

rodu

cts

Bact

erio

logi

cal

qual

ity;

Tota

l Col

iform

Rul

eIro

n an

d m

anga

nese

Corr

osio

n an

d/or

sca

ling

Orth

opho

spha

te

addi

tion

Redu

ces

optim

um

pH f

or a

lum

inum

pr

ecip

itatio

n.

If zin

c or

thop

hosp

hate

is

used

, pot

entia

l pr

ecip

itatio

n of

zin

c ca

rbon

ate

coul

d in

crea

se tu

rbid

ity.

Incr

ease

d tu

rbid

ity

from

alg

al b

loom

s in

open

rese

rvoi

rs

is po

ssib

le.

May

dec

reas

e flo

e st

reng

th.

Zinc

orth

opho

spha

te m

ay

redu

ce a

sbes

tos

cem

ent

pipe

det

erio

ratio

n.

Zinc

dep

osits

cou

ld r

educ

e ef

fect

ivene

ss o

f co

rrosio

n in

hibi

tors

.

Pote

ntia

l dec

reas

e in

bact

eria

l qua

lity

poss

ible

with

add

ition

of n

utrie

nts.

i.e.,

rese

rvoi

r blo

oms,

ba

cter

ial r

egro

wth.

Silic

ate

addi

tion

High

silic

a le

vels

can

form

pre

cipita

tes,

ca

usin

g tu

rbid

ity.

High

silic

a le

vels

can

caus

e sc

alin

g in

hot w

ater

sy

stem

s an

d bo

ilers

.

CT =

res

idua

l disi

nfec

tant

conc

entra

tion,

C, t

imes

disi

nfec

tant

cont

act t

ime,

T

DBFs

= d

isinf

ectio

n by

-pro

duct

s TH

M =

trih

alom

etha

ne


Historical Pipe Loop Studies

Pipe loop studies have commonly been used to assess corrosion and evaluate corrosion treatment strategies for a wide range of piping materials. The use of pipe loops to evaluate lead-containing materials, and particularly to evaluate lead leaching and metals pickup, is in its adolescence.

Pipe loop studies can generally be classified into one of two categories: corrosion rate determinations ormetals leaching studies. Corrosion rate determinations can be developed from weight loss analysis of metal coupons (American Standards for Testing Materials [ASTM] Method D2688, Method B [ASTM 1983]) or from one of several electrical instrumentation methods. Metal coupon weight loss analysis measures the average rate of metals loss over a given period of time. Electrical instrumentation methods, including electrical resistivity and linear polarization, measure the rate instantaneously. The weight loss method can be used to compare the corrosiveness of one supply to another and to compare the effect that various treatments will have on corrosion rate. Weight loss techniques should be comparable to determinations of rates in the distribution system if the tests are run long enough to ensure that stablity has been reached.

Metals leaching studies examine the actual concentrations of metals from the water in either a recirculating loop or a once-through loop constructed from the material of interest For recirculating loops, samples are drawn after certain recirculation periods, and as a sample is drawn, the same volume of fresh water is introduced into the loop. Flow-through loops are generally operated with an on-off cycle, with fresh water introduced continuously. Metals concentrations are then evaluated from samples collected after the water has been allowed to stand in the loop for a specified period. Designing pipe loops to simulate household plumbing, particularly water use patterns, is a practice that has been used more recently to develop data on corrosion by-product concentrations in standing water samples. The AWWARF pipe rack was designed for this purpose (EES 1990).

Several flow-throughpipe loop systems have been designed and operated by various researchers and utilities to evaluate a variety of corrosion-related parameters in drinking water. Table 2.2 contains a summary of these studies, several of which are described below.

Army Corps of Engineers' Research Laboratory Pipe Loop SystemTheAimyCorpsofEngineers'ConstructionEngineeringResearchLaboratory

pipe loop system (CERL-PLS) was designed to evaluate samples of distribution materials in an environment simulating typical operating conditions. A schematic of the CERL-PLS can be seen in Appendix A. The system is a flow-through loop that can accommodate up to four flat coupons and four pipe inserts. These coupons and inserts can be removed atvarious time intervals and evaluated for weight loss, pitting depth, and corrosion rate measurements. This basic configuration has been used in corrosion studies at several U.S. Army bases and was also incorporated into the original AWWARFpipe loop model built atthe ISWS. Although the CERL-PLS can be fitted with the major sources of lead in drinking water (i.e., lead or lead-soldered copper), it was primarily designed for corrosion rate determinations, not metals leaching studies.

Tabl

e 2.

2 Su

mm

ary

of h

isto

rical

pip

e lo

op in

stal

latio

nsFa

cilit

y or

loca

tion

Mat

eria

ls a

nd m

etho

dsDu

ratio

n of

ope

ratio

nPu

rpos

eRe

sults

Fort

Brag

g, N

.C.

Fort

Mun

roe,

Va.

U.

S. A

rmy

(Tem

kar

et a

l. 19

87)

Arm

y in

stal

latio

n,

north

east

ern

Uni

ted

Stat

es (

Tem

kar

et a

l. 19

89)

Portl

and

Wat

er

Bure

auPo

rtlan

d, O

reg.

(T

rew

eek

et a

l. 19

85)

5 C

ERL

loop

s/si

te.

3 m

onth

s Ea

ch lo

op c

onta

ins:

4 pi

pe in

serts

4 co

upon

s St

eel,

galv

aniz

ediro

n, z

inc

2 pi

pe lo

op

units

: 1

mon

th

6-ft

copp

er lo

opw

ith 2

2 so

lder

edjo

ints

(50

:50

lead

-tin)

2

galv

aniz

ed in

serts

4

Pb c

oupo

ns

2 Cu

inse

rts

2 ga

lvan

ized

iron

inse

rts

2 pi

pe lo

op u

nits

: 18

mon

ths

pipe

inse

rts p

lus

lead

-sol

dere

dco

pper

tubi

ng

Inse

rts w

ere

Blac

k iro

n G

alva

nize

d st

eel

Cop

per

Cop

per c

oate

d w

ithPb

-Sn

sold

er

Lead

As

best

os c

emen

t

Det

erm

ine

effe

ct o

f co

rrosi

on i

nhib

itor

chem

ical

s on

dis

tribu

tion

syst

em p

ipe

mat

eria

ls

usin

g th

e C

ERL

loop

.

1. E

valu

ate

usef

ulne

ss

of C

ERL-

PLS

loop

in

sim

ulat

ing

lead

di

ssol

utio

n.2.

Opt

imiz

e w

ater

qua

lity

and

redu

ce le

ad

diss

olut

ion.

1. M

easu

re c

orro

sion

ra

tes

of c

omm

on

pipi

ng m

ater

ials

.2.

Det

erm

ine

effe

ct o

f ch

lorin

e ve

rsus

chl

ora-

m

ines

on

corro

sion

rat

e.

Zinc

cor

rosi

on r

ate

low

er th

an s

teel

. C

orro

sion

rat

es fo

r m

ild

stee

l and

gal

vani

zed

(zin

c) s

teel

hig

her

in w

ater

co

ntai

ning

cor

rosi

on

inhi

bito

r. Si

gnifi

cant

pu

tting

in m

ild s

teel

.

1. Le

ad d

isso

lutio

n in

lead

-sol

dere

d di

strib

u tio

n sy

stem

s ca

n be

ap

prox

imat

ed w

ith P

b co

upon

s.2.

Sod

ium

silic

ate

was

th

e m

ost e

ffect

ive

treat

men

t fo

r th

is

syst

em.

1. C

orro

sion

rat

es

reac

hed

equi

libriu

m

afte

r 6

to

8 m

onth

s.2.

No

diffe

renc

e be

twee

n ch

lorin

e an

d ch

lora

min

es e

xcep

t fo

r le

ad in

serts

. Le

ad in

serts

cor

rode

d m

ore

rapi

dly

in

chlo

ram

inat

ed w

ater

du

e to

pH

red

uctio

n.

(con

tinue

s)

Tabl

e 2.

2 (c

ontin

ued)

Faci

lity

or lo

catio

nM

ater

ials

and

met

hods

Dura

tion

of o

pera

tion

Purp

ose

Resu

lts

High

land

Gre

en

Wat

er T

reat

men

t Pl

ant

Fort

Shaw

nee,

Ohi

o (C

ohen

and

Mye

rs 1

987)

6 Illi

nois

publ

ic w

ater

sup

plie

s (S

choc

k an

d Ne

ff 19

88)

Sant

a C

lara

Val

ley

Wat

er D

istric

t Sa

nta

Clar

a, C

alif.

(M

olna

r and

Had

en

1986

)

Gre

ater

Van

couv

er

Wat

er D

istric

t Va

ncou

ver,

B.C.

(E

ES 1

988)

Cinc

inna

ti, O

hio,

wat

er

mixe

d wi

th d

eoni

zed

wat

er

in a

labo

rato

ry s

tudy

(S

choc

k an

d G

arde

ls 19

83)

2 lo

ops

50 c

oppe

rtu

be in

serts

sol

dere

d wi

th 5

0:50

lead

-tin

sold

er p

er lo

op

12 p

ipe

loop

s wi

th 3

0 to

40

ft ga

lvani

zed

stee

l, 30

to 4

0 ft

copp

er;

galva

nize

d st

eel a

nd

copp

er c

orro

sion

test

ers;

br

ass

sam

plin

g va

lves

Flat

mild

ste

el

coup

ons

plac

ed a

t se

vera

l loc

atio

ns

with

in th

e di

strib

utio

n sy

stem

7 te

st lo

ops

with

cop

per

and

stee

l ins

erts

and

co

pper

coi

ls wi

th 1

0 50

:50

Pb-S

n-so

lder

ed

join

ts

Coi

led

lead

pip

e 10

0 fe

et in

leng

th

5 ye

ars

2 ye

ars

35 d

ays

for

base

line

1 yea

r

3 to

8 m

onth

s pe

r ex

perim

ent

Valid

ate

effe

ctive

ness

of

wat

er tr

eatm

ent

prog

ram

on

pitt

ing

corro

sion.

Eval

uate

rel

atio

nshi

p be

twee

n wa

ter q

uality

, co

rrosio

n of

gal

vani

zed

stee

l and

cop

per

plum

bing

, and

met

al

conc

entra

tions

in ta

p sa

mpl

es.

Dete

rmin

e co

rrosio

n ra

tes

with

and

with

out

treat

men

t with

zin

c or

thop

hosp

hate

.

Mea

sure

cor

rosio

n ra

tes

unde

r var

ious

wat

er

qual

ity c

ondi

tions

.De

term

ine

effe

ct o

f pH

adju

stm

ent,

chlo

rinat

ion,

an

d ch

lora

min

atio

n on

co

rrosio

n of

pre

mise

pi

ping

and

lead

leac

hing

.

Stud

y ef

fect

of p

H an

d di

ssol

ved

orga

nic

carb

on

leve

ls on

lead

sol

ubilit

y.

Soda

ash

add

ition

crea

ted

less

agg

ress

ive

wat

er.

1. Cu

, Zn,

Pb

conc

entra

tions

hi

gher

in s

tand

ing

than

in r

unni

ng

sam

ples

.

2. B

rass

sam

plin

g va

lves

co

ntrib

ute

sign

ifica

ntly

to

trac

e m

etal

co

ncen

tratio

ns in

the

sam

ples

Corro

sion

rate

was

redu

ced

afte

r add

ition

of z

inc

orth

opho

spha

te.

Elev

atio

ns in

pH

and

alka

linity

sig

nific

antly

re

duce

d co

pper

co

rrosio

n an

d ha

d a

mod

erat

e im

pact

on

redu

cing

lead

leve

ls.

Lead

leac

hing

redu

ced

at p

H le

vel >

9.0. (c

ontin

ues)

Tabl

e 2.

2 (c

ontin

ued)

Faci

lity

or lo

catio

nM

ater

ials

and

met

hods

Dura

tion

of o

pera

tion

Purp

ose

Resu

ltsSe

attle

Wat

er D

ept.

Seat

tle,

Was

h.

(Ryd

er 1

978;

Ry

der a

nd H

oyt 1

977)

Seat

tle W

ater

Dep

t. Se

attle

, W

ash.

(H

erer

ra,

Hoyt

, an

d Ki

rmey

er 1

981-

1983

)

City

of E

vere

tt Ev

eret

t, W

ash.

(R

eibe

r, Fe

rgus

on,

and

Benj

amin

198

8)

Met

ropo

litan

Wat

er

Dist

rict o

f Sou

ther

n C

alifo

rnia

Lo

s An

gele

s, C

alif.

(S

ylvia

Bar

ret,

pers

onal

co

mm

unica

tion

1988

)

Los

Ange

les

Dept

. of

Wat

er a

nd P

ower

Lo

s An

gele

s, C

alif.

(H

eum

an a

nd

Ram

berg

19

90)

Flat

cou

pons

and

pip

e in

serts

of:

Gal

vani

zed

Stee

l Bl

ack

Stee

l Co

pper

9 m

onth

s

Copp

er p

ipe

inse

rts

sold

ered

with

lead

-tin

and

tin-a

ntim

ony

sold

er;

24-h

our c

onta

ct ti

me

with

test

wat

er

Mul

tiple

pip

e co

upon

in

serts

(10

) in

one

mod

ified

ISW

S co

rrosio

n te

ster

ass

embl

y

Loop

s co

ntai

ning

'

sold

ered

cop

per

bras

s co

mpr

essio

n co

nnec

tions

Four

or s

ix flo

w-th

roug

h te

st r

acks

with

cy

lindr

ical m

ild s

teel

co

upon

s at

3 lo

catio

ns

with

in th

e di

strib

utio

n sy

stem

>180

day

s

120

days

Ong

oing

30 d

ays

Eval

uate

impa

ct o

f the

fo

llow

ing

treat

men

t ap

proa

ches

on

corro

sion

rate

s:Li

me

and

soda

ash

Lim

e an

d zin

c or

thop

hosp

hate

Sodi

um s

ilicat

e

Com

pare

met

als

leac

hing

fro

m le

ad-ti

n an

d tin

- an

timon

y so

lder

s.

Dete

rmin

e co

rrosio

n ra

tes.

Dete

rmin

e ef

fect

of

treat

men

t on

le

ad c

orro

sion

Dete

rmin

e co

rrosio

n ra

tes

on ir

on a

nd th

e ef

fect

of v

ario

us

inhi

bito

rs o

n th

ose

rate

s.

Gal

vani

zed

stee

l: pH

ad

just

men

t and

silic

a ad

ditio

n we

re e

qual

; ad

ditio

nal p

hosp

hate

do

sage

influ

ence

d co

rrosio

n ra

te.

Blac

k st

eel:

No

subs

tant

ial d

iffer

ence

in

vario

us tr

eatm

ents

.

Subs

tant

ially

mor

e le

ad

leac

hed

from

lead

-tin

sold

er.

Low

copp

er a

nd z

inc

corro

sion

rate

s.

Afte

r app

roxim

atel

y 2

mon

ths

lead

leve

ls re

duce

d to

less

than

1

ug/L

in a

ll lo

ops.

Dose

-resp

onse

cur

ves

for

carb

onat

e,

phos

phat

e an

d sil

icate

inhi

bito

rs w

ere

crea

ted.

Sou

rce:

EES

1990

.

A modified version of the CERL-PLS was constructed at a U.S. Army base in the northeastern United States (Temkar et al. 1989). The modified CERL-PLS contained two pipe loops in series (see Appendix A). The first loop contained a 6-ft (1.8-m) copper loop with 22 soldered joints (using 50:50 lead-tin solder) and two galvanized iron pipe inserts. The second loop contained four lead coupons, two copper pipe inserts, and two galvanized iron pipe inserts. The flow rate through the loop was controlled at 2 gpm (7.6 L/min), and on-off cycles were used to simulate household use. The first loop was designed to simulate premise plumbing conditions in order to evaluate metals levels from standing samples; however, the total volume within this first loop was less than the 1 -L sample required for home tap samples in the final Lead and Copper Rule.

Seattle, Wash., Water DepartmentA pipe loop study by the Seattle Water Department evaluated both flat

coupons and pipe inserts of galvanized steel, black iron, copper, and asbestos cement (Ryder 1978; Ryder and Hoyt 1977). The design for this loop can be found in Appendix A. The study was conducted for 9 months and was used to evaluate the following three treatment strategies for corrosion inhibition:

1. lime and soda ash addition to increase pH and alkalinity2. zinc orthophosphate and lime addition3. sodium silicate and lime additionThe coupons were inspected visually and corrosion rates were measured over

various exposure periods. Results indicated that increasing pHwithlime and sodaash was the most significant treatment for reducing the corrosion rate of copper. This pipe rack was not designed to simulate home plumbing systems and metals leaching, but rather to evaluate the impact of corrosion treatments on the corrosion rate of plumbing and distribution system materials.

Portland, Oreg., Water BureauThe Portland Water Bureau conducted a systemwide internal corrosion

study in 1981 (Treweek et al. 1985). The purpose was to measure corrosion of six piping materials through weight loss measurements, scale analyses, physical inspections, and water quality determinations. Two pipe racks were constructed, and weight loss measurements were made at 3-month intervals over a total of 18 months. Pipe inserts made of various materials, plus a220-ft (67-m) coil of V^-in. (12.7-mm) copper tubing soldered at 20-ft (6-m) intervals with a lead-based solder, were incorporated into the pipe rack. Sample taps were located on the coil section to measure water quality changes due to corrosion of the copper and the solder. Identical pipe racks were set up in two separate locations to evaluate the effect of chlorine and chloramine disinfection on corrosioa Home plumbing water use was simulated using mechanical valves, each controlled by a separate timer. Results from the study indicated very low corrosion rates (<5 mpy), and the lead and copper levels measured from the 220-ft (67-m) copper coils were quite variable in the 6-month interval reported (Treweek et al. 1985).


Rough estimates of the system variability from the Portland study were evaluated in Lead Control Strategies (EES 1990). Nineteen samples representing intervals of approximately 1 month were plotted for each of the two testing locations in Portland, the Sandy River Station and the Bull Run Headworks. There was one probable "outlier" hi the Bull Run data, of slightly over 1.0 mg/L Pb. Without including that point, which would severely bias the results, the mean lead value was approximately 0.13 mg/L, with a standard deviation of approximately 0.14 mg/L. For the Sandy River Station tests, the mean lead level was approximately 0.17 mg/L, with a standard deviation for the samples of approximately 0.19 mg/L.

Greater Vancouver, B.C., Water DistrictThe Greater Vancouver Water District (GVWD) constructed and operated

seven corrosion test loops as part of an overall water quality study. Each of the seven loops consisted of copper and steel inserts and copper coils with 10 50:50 lead-tin- soldered joints (see Appendix A). Copper and steel corrosion rates and metals levels were measured under various water quality conditions to determine the effects of pH adjustment, chlorination, and chloraminationonthe corrosionof premise piping. The study was performed over a 1 -year period. Results indicated that elevations in pH and alkalinity significantly reduced copper corrosion and had a moderate impact on reducing lead levels (EES 1988). This design was similar to that of the initial AWWARF pipe rack in that it incorporated both metals leaching evaluations (in the copper loop) and corrosion rate determinations (on the copper and steel inserts).

Los Angeles, Calif., Department of Water and PowerThe Los Angeles Department of Water and Power (LADWP) began a

comprehensive program of corrosion investigation in 1984. A system for measuring corrosion rates was designed and installed at four programmable corrosion testing stations (PCTSs), each receiving different source waters or blends. Each PCTS contained four to six independently controlled lines with calibrated flow rates. The corrosion rate measuring system consisted of reusable coupon holders (RCHs) loaded with test specimens hi the laboratory and later installed in the PCTSs. The RCHs each held three cylindrical (pipe-analogous) iron pipe coupons that had been sandblasted and then coated on the outside and ends with epoxy paint to restrict corrosion to the interior surfaces. Weight loss analysis of the coupons after exposure provided the corrosion rate data. One of the RCHs was mounted prior to treatment, and the second was placed downstream of chemical injection and motionless mixing. Appendix A contains schematics for both the PCTSs and RCHs.

The exposure period was normally 30 days, but two 180-day confirmation tests were performed later with similar results. The following treatments were tested with a minimum of five different doses per treatment:

• carbonate system adjustments using lime, caustic soda, and a "synthetic lime" consisting of CaCl2 (calcium chloride) and either NaOH (caustic soda) or Na^Oj (soda ash)

• phosphate system adjustments using pure phosphate chemicals, zinc phosphate inhibitors, and ZnCl2 (zinc chloride) alone

• silicate system adjustments using sodium silicate


The results indicated that carbonate system adjustments were inferior to phosphate system adjustments for controlling iron corrosion. Caustic soda was not effective, lime was moderately effective, and the synthetic lime was the most effective of the carbonate system chemicals. It was also found that pure phosphate chemicals increased iron corrosion and that zinc alone had only a slight positive effect at high doses. The combination of zinc and phosphate achieved the greatest corrosion reduction observed. It was also found that the zinc:phosphate ratio had an effect on the shape of the dose response curve and on the maximum inhibition achieved. One silicate inhibitor showed substantial effect in a narrow dose range.

Iron corrosion reduction tests were performed first because the L AD WP was experiencing substantial iron corrosion in some parts of the city. The most effective chemicals are now being tried in response to the final Lead and Copper Rule on a tin- lead-soldered pipe loop recently designed and installed in the various PCTSs.

Illinois State Water Survey AWWARF Pipe Rack____

The original AWWARF pipe rack was designed by the ISWS as part of AWWARF's lead control strategies manual project (EES 1990). The rack was designed to simulate water conditions encountered in the plumbing of atypical home. These water conditions included

temperature pressure velocitythroughputvolume typical usage

Except for the pipe materials to be studied in the test pipe loops, nonmetallic pipe and fittings were selected in the construction of the manifold and connecting piping to minimize extraneous sources of metal contamination.

The sizeof pipe used was chosen to limitthe water velocity in the pipe in order to prevent erosion of the pipe metal. The Copper Development Association (CDA 1972) recommends installation of nominal Vi-in. (12.7-mm) tube to provide service to a tap at the kitchen sink. The N ACE recommends a maximum design velocity of 4 fps (1.2 m/s) for type K copper tube (N ACE 1980). These guidelines represent the standard for household plumbing and established the minimum nominal pipe size at Vi in. (12.7 mm) for the piping material to be tested in the pipe loops.

The USEPA sample monitoring protocol forlead or copper indrinking water specifies that 1,000 mL of water standing for aminimum of 6 hours be collected from the kitchen tap in targeted single-family homes. This requirement established several constraints on the design of the test loops. The 1,000-mL sample requirement for a standing sample from a test loop is a constraint on the minimum length for the pipe material being tested. Fornominal V£-in. (12.7-mm) tube or pipe materials, between 17 and 26 ft (5.2 and 7.9m) of pipe length are needed to meetthis volume requirement. This difference in length is due to the difference hi the ID of various materials that are defined as nominal V£-in. (12.7-mm) tube.


The design for the standard pipe rack evolved after the aforementioned constraints, current plumbing practices, and proposed regulations were weighed against the practical needs of water utility corrosion control programs. The configuration of the AWWARF pipe rack as constructed by the ISWS is shown in Figure 1.1 on page 3. A CERL-PLS tester was included in the configuration to measure metal corrosion rates because corrosion control programs implemented for reductions in lead or copper concentrations may not relate to the life of other pipe materials. Therefore, the overall pipe rack system consisted of replicate test pipe loops and a CERL-PLS corrosion rate tester. The construction, operation, and results of this initial pipe rack study are described below.

ConstructionThe initial AWWARF pipe rack consisted of aPVC manifold and connecting

piping, with three replicate test loops and a CERL-PLS corrosion rate testing apparatus. The test loops were three identically constructed pipe sections prepared from lead tube, copper tube, and copper tube with numerous soldered joints. Each of the three soldered copper test loops was constructed by different plumbers with varying degrees of experience. The performance of the AWWARF pipe rack was investigated after the installation was completed at the ISWS Research Center. Because of the limited time available for the project, each of the test materials was evaluated over a 30-day period.

Normal Corrosion Test OperationThe purpose of the initial testing protocol was to determine if identical test

loop sections of the pipe rack provided analytical results that were also statistically identical. Each test loop section was exposed to the same influent water quality, ambient temperature, and flow conditions. It was assumed that any analytical differences would be attributable to design, construction, or material differences in the pipe test sections.

The pipe rack was operated at a flow of 1 gpm (3.8 L/min) through each replicate test loop (a total of 3 gpm [11.4 L/min] through the pipe rack), with an on- off flow cycle to simulate home wateruse. A monitoring and sampling protocol was established to reduce variability in sampling. A sample of the influent water was collected immediately prior to the water being shut off after it had flowed for 30 minutes or more. This sample was used to assess the quality of the water entering the replicate loop sections prior to the 8-hour stagnation period. After the standing period, water samples were collected from each test loop section to be analyzed for temperature, pH, total inorganic carbon (TIC), metals, alkalinity, ammonia, and chlorine residual. All samples were collected with the water continuously flowing from the sampling tap at a slow rate.

Evaluation of Test ResultsWater quality results from the test pipe loops were evaluated statistically

using the method known as analysis of variance (ANOVA). These evaluations were made to determine if test sections of the same pipe material produced identical


chemical effects in the water contained within each loop. Except for the lead concentrations, the ANOVA test did not detect any significant differences between the test loop sections for any of the measured parameters.

A significant difference in lead concentrations (at the 95 percent confidence level) was found in the ANOVA test for both the replicate lead loops and the replicate lead-soldered copper loops that were installed in the pipe rack. The mean lead values of all three loops of the lead-soldered copper tube construction were statistically different from each other. For the lead tube test sections, Loop 1 was significantly different from Loop 3, but Loop 2 was not significantly different from Loop 1 or Loop 3.

The ANOVA method assumes that each data set has a normal distribution frequency and that the variance is equal between sets. A check of the lead values from the replicate lead test loop study indicated that the distribution might not be normal. When this indication occurs, a nonparametric test is recommended by statistical reference works. However, a nonparametric (Kruskal-Wallis) test also confirmed that the differences in mean lead values were significant. The statistical differences between the loops were seen only for lead. There may have been unidentified factors contributing to this observation other than the variability in the construction of the test sections.

Utility Participants___________________

The initial operation of the AWWARF pipe rack at the ISWS in 1989 left many unanswered questions about the most appropriate protocol for use of this system in evaluating corrosion control treatments to reduce lead and copper levels. These questions included

• How long would it take for standing lead and copper levels measured from the test loops to stabilize?

• How long should the AWWARF pipe rack be operated in order to determine any differences between treatments?

• What is the most appropriate sampling protocol to evaluate these differences in treatment?

• How could data be evaluated to assess the effectiveness of various treatment approaches?

• Would standing lead and copper level results from the AWWARF pipe rack correlate to home tap sampling results?

• What are the costs associated with constructing and operating the AWWARF pipe rack?

To assist in answering these questions, the following utilities and the ISWS agreed either to build the AWWARF pipe rack or to incorporate one of the test loops designed according to the initial AWWARF pipe rack study into their existing corrosion test system:

• Contra Costa Water District, Concord, Calif.• Fort Worth Water Department, Fort Worth, Tex.• New York City Bureau of Water Supply and Wastewater Collection,

New York, N.Y.


• Philadelphia Water Department, Philadelphia, Pa.• Portland Water Bureau, Portland, Oreg.Of the utilities participating in the project, two (Philadelphia and New York

City) incorporated a flow-through AWWARF test loop into their existing corrosion pipe racks. These utilities evaluated various treatment schemes for reducing lead levels. The remaining three utilities (Contra Costa, Fort Worth, and Portland) and the IS WS built stand-alone AWWARFpipe racks with three replicate test loop sections. These project participants did not evaluate corrosion treatments; rather, they generated data on the variability of water quality measurements from test loop sections and tap monitoring, and they also provided data for determining the correlation between distribution system data and pipe rack data.

In addition to providing information for use in developing a protocol for constructing and operating pipe racks and evaluating pipe loop data, the participating utilities also collected valuable information on establishing distribution system monitoring programs and public educationmaterials. The following sections provide a brief description of each of the utilities, and Tables 2.3 through 2.5b contain background water quality and treatment information.

Illinois State Water SurveyThe ISWS, located in Champaign, 111., developed the original AWWARF

pipe rack assembly in 1989 to evaluate the lead leaching potential of public water supplies. The original AWWARF pipe rack was constructed and installed in the ISWS laboratory building, which is serviced by water from the Northern Illinois Water Corporation (NIWC).

The NIWC obtains its water from several wells that tap an aquifer formation known as the Teays River underground waterway. The wells are about 300 ft (91.4 m) deep and are located over arelatively wide area. Wells are pumped directly either to the East Treatment Plant or the West Treatment Plant. The East plant has a peak capacity of 10 mgd (438 L/s) and the West plant has apeak capacity of 20 mgd (876 L/s). In 1991, NIWC's average daily production was 18.3 mgd (802 L/s), and its peak daily production was 27 mgd (1,183 L/s).

Because the source water contains excessive hardness and iron, treatment at both the East and West plants utilizes a split-treatment lime-softening process to reduce hardness and to remove iron. Ferric chloride, sodium silicate, sulfuric acid, chlorine, and fluoride are added in addition to lime to condition the water and to comply with drinking water regulations. The NIWC's distribution water is generally consistentin quality and is notcorrosiveto common plumbing materials. At the ISWS site, the 1991 mean values for pH, alkalinity, and calcium were 8.90,129 mg/L as CaCO3, and 15.6 mg/L as Ca, respectively.

A short-term study was conducted at the ISWS site in 1989 using the AWWARF pipe rack to investigate the variability in trace metal concentrations of samples collected from identically designed test loops. During that study, the ISWS employed the existing pipe rack over a 1 -year period to investigate long-term leaching trends and the effect of preconditioning on pipe loop performance. Three newly constructed 50:50 tin-lead-soldered copper tube loops were used for the study. Metals dissolution and water chemistry in these test loops were monitored at daily to weekly intervals to determine the time required to reach steady state conditions and

Tabl

e 2.

3 W

ater

sup

ply

info

rmat

ion

for u

tility

par

ticip

ants

Util

ity

nam

e Lo

catio

n

Cont

ra C

osta

Co

ncor

d, C

alif.

W

ater

Dist

rict

Fort

Wor

th

Fort

Wor

th,

Wat

er

Tex.

D

epar

tmen

t

New

York

City

N

ew Y

ork,

N.Y

. Bu

reau

of

Wat

er a

nd

Cus

tom

ers

serv

ed

sniir

t,0 O

fR

etai

l W

hole

sale

su

pply

200,

000

200,

000

Cont

ra C

osta

Can

al

447,

108

203,

425

Lake

Wor

th

Benb

rook

Lak

e

Ceda

r Cre

ek

Rich

land

Cha

mbe

rs

1 0,0

00,0

00

Cats

kill D

elaw

are

Crot

on

Type

of

supp

ly

Sacr

amen

to-

San

Joaq

uin

river

del

ta

Rese

rvoi

r

Rese

rvoi

r

Rese

rvoi

r Re

serv

oir

Rive

r

Rive

r

Aver

age

flow

(m

gd)

37.0

68.6

2.4

40.1

26

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1,35

0.0

150.

0

Peak

flo

w

(mgd

)

70-7

5

112.

3

33.9

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37

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1,90

0.0

300.

0

Trea

tmen

t pl

ant(s

)

Bollm

an

North

, So

uth

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No

rth,

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h Ho

lly

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g Hi

lls

Rollin

g Hi

lls

NA

NA

Trea

tmen

t

Floc

cula

tion-

coag

ulat

ion,

fil

tratio

n, c

orro

sion

cont

rol,

disin

fect

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Floc

cula

tion-

coag

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ion

Filtr

atio

n-di

sinf

ectio

n,

corro

sion

cont

rol,

pH-

alka

linity

adj

ustm

ent

Floc

cula

tion-

coag

ulat

ion

Filtr

atio

n, c

orro

sion

cont

rol,

disin

fect

ion

Disin

fect

ion,

pH

adju

stm

ent

Disin

fect

ion

Was

tew

ater

Co

llect

ion

Portl

and

Portl

and,

Ore

g.

453,

000

269,

000

Bull

Run

Rive

r W

ater

Bur

eau

Phila

delp

hia

Phila

delp

hia,

1,

600,

000

250,

000

Dela

ware

Rive

r Ri

ver

Wat

er

Pa.

Dep

artm

ent

Schu

ylkill

Rive

r Ri

ver

125

203 58 86

209

NA

289

Baxt

er

87 126

Belm

ont a

nd

Que

en L

ane

Disin

fect

ion

Conv

entio

nal t

reat

men

t pl

us p

H ad

just

men

tCo

nven

tiona

l tre

atm

ent

plus

cor

rosio

n in

hibi

tor

NA =

not

app

licab

le

Tabl

e 2.

4 Tr

eatm

ent i

nfor

mat

ion

for u

tility

par

ticip

ants

Con

tra C

osta

Bollm

an

Trea

tmen

t Tr

eat-

Dos

age

proc

ess

men

t (m

g/L)

Raw

wate

r sto

rage

X

Pred

isinf

ectio

n an

dox

idat

ion

Chlo

rine

X 1-

2Ch

lorin

e di

oxid

eC

hlor

amin

esO

zone

KMnO

4

Lim

e an

d so

da a

shso

fteni

ng

Rapi

d m

ixIn

-line

hyd

raul

ic X

In-li

ne m

echa

nica

lIn

-line

sta

ticBa

sin m

echa

nica

l

Floc

cula

tion

and

coag

ulat

ion

Alum

inum

sal

ts

X 10

-40

Iron

salts

pH a

djus

tmen

tsPo

lymer

s

Settl

ing

and

sedi

men

tatio

nSe

ttlin

g an

d co

ntac

tch

ambe

rsSe

dim

enta

tion

and

clar

ifica

tion

X

Fort

Wor

th

New

Yor

k C

ity

Phila

delp

hia

Nor

th a

nd S

outh

Hol

ly

Trea

t- D

osag

em

ent

(mg/

L)

X 2-

3

X 0.

5-1

.5

X X

8-24

X

10-1

5X

0.

5-1.

5

X

Cat

skill

Rol

ling

Hills

D

elaw

are

Cro

ton

Baxt

er W

TP

Trea

t- D

osag

e Tr

eat-

Dos

age

Trea

t- D

osag

e Tr

eat-

Dos

age

men

t (m

g/L)

m

ent

(mg/

L)

men

t (m

g/L)

m

ent

(Ib/m

il ga

l)

XX

X

X 1-

2 X

1-2

X (o

ccas

iona

l)X

2-

3

X

0.5-

1.5

X

20

X X X

15-5

0 X

10

0X

10

-12

X

0.5-

3.0

X

X

Por

tland

Bull

Run

Trea

t- D

osag

em

ent

(mg/

L)

(con

tinue

s)

Tabl

e 2.

4 (c

ontin

ued)

Trea

tmen

t pr

oces

s

Con

tra C

osta

Bol

lman

Trea

t- D

osag

e m

ent

(mg/

L)

Fort

Wor

th

Nor

th a

nd S

outh

H

olly

Trea

t- D

osag

e m

ent

(mg/

L)

Rol

ling

Hills

Trea

t- D

osag

e m

ent

(mg/

L)

New

Cat

skill

D

elaw

are

Trea

t m

ent

Dos

age

(mg/

L)

York

City C

roto

n

Trea

t m

ent

Dos

age

(mg/

L)

Phila

delp

hia

Baxt

er W

TP

Trea

t- D

osag

e m

ent

(Ib/m

il ga

l)

Portl

and

Bull

Trea

t m

ent

Run

Dos

age

(mg/

L)

Filtr

atio

n Sl

ow s

and

Rapi

d sa

nd

Dual

med

ia a

ndm

ultim

edia

D

iato

mac

eous

earth

Pr

essu

re fi

ltrat

ion

Org

anics

rem

oval

G

AG a

dsor

ptio

n PA

C ad

ditio

n Re

sin a

dsor

ptio

n Ai

r stri

ppin

g

Post

disi

nfec

tion

Chl

orin

e Ch

lorin

e di

oxid

e C

hlor

amin

es

X

3-5

X

2.

5-5.

0 X

2.

0-20

.0

1.5-

3.5

1-1.

5 X

1.

9 X

2.

0-3.

0

1-2

1-2

X (o

ccas

iona

l)

401.

0*Am

mon

ia

Fluo

ridat

ion

X 1

Cor

rosi

on c

ontro

l pH

adj

ustm

ent

X 7-

8.6

Alka

linity

ad

just

men

t C

orro

sion

in

hibi

tor

Oth

er

X 5

X 2.

5 X

X X

8

X X

100f

KMnO

4= p

otas

sium

per

man

gana

te*

Com

bine

d re

sidu

al m

aint

aine

d at

rese

rvoi

rs

f Li

me

befo

re fl

occu

latio

n an

d se

dim

enta

tion

Tabl

e 2.

5a

Wat

er q

ualit

y in

form

atio

n fo

r util

ity p

artic

ipan

ts (C

ontra

Cos

ta a

nd F

ort W

orth

)Fo

rt W

orth

,

Wat

er q

ualit

y pa

ram

eter

s

Tem

pera

ture

, cC

PH TDS

(mg/

L)Al

kalin

ity (

mg

CaC

O/L

)Ha

rdne

ss (

mg

CaC

O/L

)

Nitra

te (

mg/

L)Iro

n (m

g/L)

Man

gane

se (

mg/

L)Ap

pare

nt c

olor

(cu)

True

col

or (c

u)Tu

rbid

ity (

ntu)

Tota

l col

iform

s (n

umbe

r/100

Tota

l org

anic

carb

on (

mg/

L)Fr

ee c

hlor

ine

(mg/

L)To

tal c

hlor

ine

(mg/

L)To

tal t

rihal

omet

hane

s (u

g/L)

Dis

tribu

tion

syst

em p

aram

eter

s

PH Tota

l col

iform

s,(n

umbe

r/100

mL)

Hete

rotro

phic

plat

e co

unt

(cfu

/mL)

Con

tra

Influ

ent

— 8.2

399

79.7

122

2.9

1.29

20.

037

— — 15m

L)

187

5.8

— —

Con

tra C

osta

Sam

ples

/yr

Aver

age

(rang

e)

156

8.5

(8.1

-8.8

)

2,50

0 0

(0-1

)

2,50

0 15

(0

-500

)

Cos

ta Effl

uent

19.7

8.6

300

75 125

<.1

0.06

0.00

1— <5 0.06 0 — — 0.85 78

Fort

Nor

th a

nd

Sam

ples

/yr

210

210

210

Nor

th a

nd S

outh

Hol

ly

Influ

ent

17 8.07

226

130

141

0.1 — — 11 12 14 5

4.56 — —

Wor

th,

Sout

h H

olly

Effl

uent

16 8.14

248

135

135

0.06

0.03

<.02 — 1

0.16 — 4.35

0.04

2.59

23.8

Aver

age

(rang

e)

8.09 0 2

(7.9

-6.3

2)

(0-0

)

(2-6

0)

Fort

Wor

th,

Rol

ling

Hill

s

Influ

ent

20 7.83 171

77 87 0.38 NA

NA 11 12 9.7 1

4.97 — —

Fort

Wor

th

Rol

ling

Hill

s

Effl

uent

8.57

136

79 69 0.45

<0.0

20.

05 — 10.

14 — 4.37

0.04

2.59

20.5

^Sa

mpl

es/y

r Av

erag

e (ra

nge)

§

210

8.28

210

0

210

4

(8.0

8-8.

55)

(0-0

)

(0-5

40)

| § a. to

— in

dica

tes

data

not

ava

ilabl

e

Tabl

e 2.

5b

Wat

er q

ualit

y in

form

atio

n fo

r util

ity p

artic

ipan

ts (N

ew Y

ork

City

, Phi

lade

lphi

a, a

nd P

ortla

nd)

New

Yor

k Ci

ty, C

atsk

ill D

elaw

are

Wat

er q

ualit

y pa

ram

eter

s

Tem

pera

ture

, °C

PH IDS

(m

g/L)

Alka

linity

(mg

CaCO

3/L)

Hard

ness

(m

g Ca

CO3/L

)Ni

trate

(m

g/L)

Iron

(mg/

L)M

anga

nese

(m

g/L)

Appa

rent

col

or (c

u)Tr

ue c

olor

(cu

)Tu

rbid

ity (

ntu)

Tota

l col

iform

s (n

umbe

r/100

mL)

Tota

l org

anic

carb

on (

mg/

L)Fr

ee c

hlor

ine

(mg/

L)To

tal c

hlor

ine

(mg/

L)To

tal t

rihal

omet

hane

s (u

g/L)

Dis

tribu

tion

——

syst

em p

aram

eter

s

PH Tota

l col

iform

s(n

umbe

r/100

mL)

Hete

rotro

phic

plat

eco

unt

(cfu

/mL)

Influ

ent

min

imum

33 6.1 9 4 8 .03

.01 0 0 — 0 — 1 — —

Influ

ent

max

imum

70 7.9

50 23 24 .60

.35

.17

35 — 10 — 5 — —

Effl

uent

. — — 53 10.6

20.1

<.00

1.0

5.0

2— 6 0.

9— 2.

30.

7— 27

.0

New

Yor

k C

ity,

Cat

skill

Del

awar

e

Sam

ples

/yr

14,0

00

14,0

00

1 4,0

00

Aver

age

(rang

e)

— —

9 (2

1-3

,968

)

pmia

aeip

n

Influ

ent

Varia

ble

7.33 160

35 60 1.24 .47

.07

30 87.

71 — 3.0

— — 1.9

na,

Baxt

er

Effl

uent

Varia

ble

8.22 179

41 88 1.35

<.05

<.05 4 3

0.29 — 2.3

<.05 2.0

75.3

Phila

delp

hia

Sam

ples

/yr

. —

4,10

0

4,10

0

Ran

ge—

0-0.

317

0-19

0

Portl

and,

Bu

Influ

ent

10.8

7.0

23 8.8

7.6

0.04

0.06

0.01 — 5

0.32 4.1

1.4

— —

Por

tland

Sam

ples

/yr

50

5,55

1

1,43

2

ii nu

n

Effl

uent

11.2

6.8

— 10.8

— 0.10 — — — 5

0.34 — 1.4

— — 20

Res

ults

f

6.9

62 p

ositi

ves

<1

— in

dica

tes

data

not

ava

ilabl

e*

Mea

n va

lues

for 1

992;

Influ

ent =

hea

dwot

ks s

tatio

n 2;

Effl

uent

= P

owel

l But

te R

eser

voir

t M

edia

n va

lues

for p

H an

d H

PC


to evaluate the variability between test loops. In addition, a CERL-PLS was incorporated to determine the corrosion rates of copper, lead, and solder specimens by weight loss methods.

New York City Bureau of Water Supply and Wastewater CollectionThe New York City Bureau of Water Supply and Wastewater Collection

serves over 8 million consumers (1.5 bgd [65,719 L/s]) from two unfiltered surface water systems: the Catskill Delaware system, which provides 90 percent of the supply, and the Croton system, which provides 10 percent. Currently, both systems are chlorinated for disinfection, and caustic soda (50 percent sodium hydroxide) is added to the Catskill Delaware system after hydrofluorosilicic acid (fluoride) addition to return the pH to 7.1. The Croton system has a stronger buffering capacity due to the geology of its watershed and does not require caustic soda addition to maintain its pH. The Croton system has been impacted by development in its watershed, and plans are under way to filter the supply before the year 2000.

New York City has developed acomprehensive planfor evaluating treatment alternatives to reduce the level of corrosion by-products in the water system. The plan seeks to achieve optimization of water treatment overall rather than to attain optimum treatment of a single parameter such as lead or copper. A set of pipe racks was constructed to evaluate the impact of various treatment approaches on corrosion rates, corrosion by-productlevels, and disinfection by-product formation. AWWARF test loop sections of lead, copper, and lead-soldered copper were added to the exi sting racks to evaluate corrosion by-product levels.

Philadelphia Water DepartmentThe Philadelphia Water Department serves approximately 1.6 million

customers with over 500,000 service connections, as well as several wholesale customers. Philadelphiahas two surface water supplies, the Delaware and Schuylkill rivers, which receive conventional treatment. Delaware River water is treated at the Baxter Water Treatment Plant (WTP), where corrosion control is achieved through pH elevation (pH=8.1). Schuylkill River water is treated at the Belmont and Queen Lane WTPs, where the pH is 7.1 and 7.3, respectively. Zinc orthophosphate is added at both the Belmont and Queen Lane WTPs for corrosion control.

An estimated 10 to 20 percent of the service connections in Philadelphia are original lead pipe. These lines appear to be well passivated at this time. Since the 1970s Philadelphia has been conducting corrosion control studies and monitoring corrosion control effectiveness using various methods. Most recently, Philadelphia developed a corrosion control strategies study that involved construction of pipe racks at the Baxter, Belmont, and Queen Lane WTPs. These pipe racks incorporated a modified version of the CERL-PLS and contained both steel pipe inserts and coupons (lead, mild steel, and copper coated on one side with 50:50 lead-tin solder).

Philadelphia's participation in the AWWARF pipe loop protocol project involved incorporating two test loop sections into each of the three existing pipe rack systems at the Baxter WTP. The test loops were constructed of lead pipe and

lead-soldered copper pipe. The pipe rack systems were used to evaluate the effectiveness of three different corrosion control strategies (including one control rack representing existing conditions).

Contra Costa Water DistrictThe Contra Costa Water District (CCWD) provides drinking water to

approximately 200,000 people in the Diablo Valley of central Contra Costa County in California. Communities served include Clayton, Clyde, Concord, Martinez, Pacheco, Pleasant Hill, Port Costa, and Walnut Creek.

The CCWD's sole source of water is Rock Slough in the Sacramento-San Joaquin river delta, within the tidal influence of San Francisco Bay. The water is subject to significant seasonal changes in water quality, particularly with respect to total dissolved solids. Current treatment includes high-rate filtration, postdisinfection with chloramines, and pH adjustment to approximately 8.6 for corrosion control.

The CCWD did not anticipate a lead problem in its distribution system because the system is relatively new. There were no known lead service lines or pigtails in the system, and the major source of lead was believed to be lead-soldered copper plumbing and brass fixtures in consumers' homes. Therefore, Contra Costa built and operated an AWWARF pipe rack composed of lead-soldered copper test loops.

Fort Worth Water DepartmentThe Fort Worth Water Department serves a total population of over 680,000

people from four surface water supplies: Lake Worth, Benbrook Lake, Cedar Creek Reservoir, andRichland Chambers Reservoir. Water from Lake Worth and Benbrook Lake is treated at the North and South Holly plants and the remaining two sources receive treatment at the Rolling Hills plant. Treatment includes full conventional filtration and chloramination for postdisinfection.

Historically, Fort Worth has had few problems with lead levels measured from tap samples. Lead levels from a home tap monitoring program that collected samples from targeted water department employees' homes ranged from <2.0 to 12 ug/L; however, there have been occasional incidences of very high standing tap levels associated with new plumbing and/or paniculate lead. The major source of lead in the system is lead-soldered copper piping in the home; however, there are an unknown number of 'lead service connections and services with lead goosenecks still in existence, which are currently being replaced under an ongoing program. With both lead sources in existence in the Fort Worth system, the water department decided to build two AWWARF pipe racks, one containing test loops of lead-soldered copper and the other containing test loops of lead pipe.

Portland Water BureauThe Portland Water Bureau (the bureau) delivers water to a metropolitan

population of about 720,000 from its Bull Run watershed. The watershed is highly protected and the source is currently unfiltered. The water is characterized by low


dissolved solids, low alkalinity, and neutral to slightly acidic pH. Treatment consists of disinfection with chloramines prior to distribution in order to maintain a combined chlorine residual of approximately 1 mg/L in the distribution reservoirs.

The major sources of lead in the bureau's system are lead goosenecks and lead-soldered copper plumbing in the homes. The bureau has initiated numerous monitoring programs to assess lead corrosion in the system. In one program, the effect of plumbing age on standing lead levels at the tap was studied. Overnight standing samples were measured for lead in homes (with lead-soldered copper plumbing) built before 1981 and in homes built in 1981 through 1984. Results indicated that average lead levels were higher in the newerhomes. In another study, samples collected from services with lead goosenecks all had lead levels above 50 ug/L. The bureau is currently undergoing scheduled replacement of these lead goosenecks in its system, to be completed by 1995. With the reduction in the lead gooseneck source of lead, the bureau decided to evaluate lead-soldered copper test loops in its AWWARF pipe rack.

Chapter 3

Methods and MaterialsThis chapter containsadescriptionofthemethods and materials used by each

study participant in implementing its AWWARF pipe rack study. Construction and operating procedures were recommended to each of the participating utilities based on the original AWWARF pipe rack design. The procedures are described in Appendix B.I. Although these procedures were recommended to eachparticipant, not all were able to construct and operate the system as described because of existing corrosion control studies and currentoperating practices. The discussion thatfollows summarizes each participant's actual construction and operating procedures.

Illinois State Water Survey____________

BackgroundThe original AWWARFpipe rack was constructed and installed atthe ISWS

and was placed in operation for the first time in February 1989. Three identical test loops, constructed from lead tube, coppertube, and lead-soldered copper tube, were each tested for 30 days in the pipe rack. This short-term study was undertaken to evaluate the overall performance of the pipe rack and to determine the variability in metal concentrations of standing samples collected from identical test loops (EES 1990). The data derived from the 1989 study indicated that the construction techniques used in assembling the lead-soldered coppertube testloops were responsible for significant variability in the lead concentrations found in standing samples. Visual observations and analytical data indicated that the variability was due to differences in the techniques used by the individuals who assembled the test loops. Residues found in soldered joints implicated flux and fluxing procedures as the factor most likely responsible for the observed variability in lead concentrations from otherwise identical test sections. These observations led to the establishment of flushing and assembly guidelines for the lead-soldered copper tube test loops.

Pipe Rack Construction and StartupBecause the original AWWARF pipe rack was permanently installed in a

cement-block-and-glass enclosure adjoining the ISWS analytical laboratory, the major portion of the pipe rack was already constructed and ready for reuse in the current study. The complete design and construction details for the pipe rack and test

67


loops are fully described in Lead Control Strategies (EES 1990). For this second study, three new and identical lead-soldered copper tube test loops were to be assembled from Vfc-in. (12.7-mm) type L copper tube according to the AWWARF specifications. All three testloops were to be assembled by one individual to minimize the variability in construction techniques observed in the previous AWWARF study. An experienced in-house shop mechanic was given the specifications and instructed to assemble three test loops. The resulting test loops were poorly constructed and developed many leaks during testing. These test loops were discarded and the University of Illinois plumbing shop was contracted to assemble a second set of test loops. When completed, the second set of test loops was found to be uniform in quality, leak free, and acceptable for use in the study.

Prior to assembly of the lead-soldered copper tube test loops, the plumber was supplied with the solder and liquid flux remaining from the earlier study. Copper tube and fittings were obtained from a local plumbing distributor. The plumber was instructed to follow the soldering sequence outlined in Appendix B. 1 f or assembling soldered coppertube test loops. The amount of solderused to assemble the three test loops was determined by preweighing the roll of solder, deducting solder loss due to splattering, and reweighing the roll of solder after assembly. The average amount of solder used per test loop was 55.0 g, which compares well with the average of 52.7 g/test loop determined in the previous AWWARF study.

The plumber was instructed to use air rather than water to leak test the finished loops. Air was specified because the soldered test loops were to be used to investigate the effectiveness of water flushing procedures in removing flux residues. The assembled test loops were returned to the ISWS laboratory, where the water flushing study was to be conducted.

Need to Precondition Test LoopsA pipe test loop must be flushed or preconditioned before use to remove

contaminants from the loop and to produce a standard surface condition. Preconditioning may also tend to minimize the time required for metal dissolution rates to stabilize and approach equilibrium during pipe loop studies.

During the fabrication of test loops, some contamination may be unavoid able for certain materials; i.e., flux residues in lead-soldered copper tube. These residues have been reported to be responsible for corrosion and metal dissolution of coppertube. Very little information is available on removing contaminants, butafew references cite the use of aggressive procedures utilizing dilute acid solutions, hot water, detergents, and extremely high water velocity (Neff and Lane 1987; Loucks 1968,; Gray and Heinz 1991; D'lppolito 1989; NACE 1980).

A nonaggressive cleaning procedure is needed to remove the contaminants or at least to minimize the leaching of contaminants to a consistent acceptable level. The cleaning or preconditioning procedure should encourage the formation of naturally occurring films on the metal surface, as would happen in plumbing exposed to the water supply under study. Flushing the test loops with hot water appeared to be the most acceptable procedure for cleaning and preconditioning lead-soldered copper pipe or lead tube. The increased water temperature would increase the dissolution rate of flux residues and encourage the formation of naturally occurring films. This supposition assumes that anincrease in temperature is the only change that

Methods and Materials 69

occurs in the water quality. To test this supposition, the three lead-soldered copper tube test loops were flushed with both cold and hot water prior to installation in the AWWARF pipe rack.

Flushing StudyThe flushing study was designed to monitor the effect of various flushing

procedures on zinc, copper, and lead concentrations of standing samples collected from the pipe test loops. The three test loops were subjected to the same five flushing events. The conditions were controlled for each event, as described in the following sections.

Event 1Each pipe test loop was connected by a plastic hose to a cold water service

line in the ISWS laboratory building. Each test loop was then individually flushed with unheated (55 to 60°F [12.8 to 15.6°C]) water at a high velocity (8.25 fps [2.5 m/s]; 6.0 gpm [22.8 L/min]) for 12 minutes. This flushing was done to remove debris and to recheck for leaks. The water flow was then shut off and water was allowed to stand in the loops under pressure for 20 hours. After standing, all of the water contained in each loop (approximately 3 L) was drained into a polyethylene container. A composite sample was collected from each container, was acid preserved, and was put into a bottle for trace metal analyses.

Event 2Following event 1, each test loop was connected to an adjacent hot water

service line. The test loop was then flushed with hot tap water (150 to 160°F [66 to 71°C]) for 12 minutes at a lower velocity (0.7 fps [0.21 m/s]; 0.5 gpm [1.9 L/min]) than was used in event 1. The lower velocity was used to maintain the water temperature due to the limited capacity of the waterheater. The water flow was again stopped and the water was allowed to stand for 20 hours under pressure. After the water stood in the pipe loops for 2 hours, the water temperature decreased to the ambient room temperature. The standing samples were collected from each loop for trace metal analysis, as described for event 1.

Event 3Following event 2, the test loops were connected in series to the hot water

service line. This connection was made to conserve hot water and to reduce the length of the flushing study. The test loops were then flushed with the 150 to 160°F (66 to 71°C) water for 2 hours at the lower velocity of 0.7 fps (0.21 m/s). The water flow was again stopped and the water was allowed to stand for 20 hours under pressure. Standing samples were collected for each loop as described for event 1.

Event 4The flushing and sampling procedure was the same as in event 3 except that

the test loops were flushed for 24 hours with 150 to 160°F (66 to 71°C) water.


Event 5The flushing and sampling procedure was the same as in events 3 and 4

except that the test loops were flushed for 76 hours with hot water.

Cumulative ResultsBecause the study used the same test loops for each flushing event, the metal

dissolutionresults for each event reflected the cumulative effects of all the preceding events. A summary of the total exposure time and flushing conditions for each flushing event is tabulated as follows:

Flushing conditionsEvent Temperature Total flush

number Duration (hours) °F(°C) time (hours)1 0.17 58 (14.4) 0.172 0.20 163 (72.7) 0.373 2.00 153 (67.2) 2.374 20.00 156 (68.8) 22.375 72.00 156 (68.8) 94.37

The dissolution of copper, zinc, and lead from each test loop was determined after each flushing event. Samples were collected after standing in the loops for approximately 20 hours following each event. Duplicate composite samples were withdrawn from the total volume of water contained in and drained from each loop. The copper, zinc, and lead concentrations of the duplicate samples were determined by the appropriate atomic adsorption spectrophotometer method. The analytical results and observations from the flushing study are presented in Chapter 4. After the flushing study was completed, the three lead-soldered copper tube test loops were immediately mounted in the AWWARF pipe rack.

Control and Operation of the Pipe RackDuring the first AWWARF study (EES 1990), the pipe rack was operated

for three 30-day periods. The purpose for continuing the AWWARF study at the ISWS site was to determine whether the rack would operate reliably over a much longer period. This second study was designed to operate the pipe rack continuously for at least 1 year while monitoring the variability in trace metal contamination during that time. The water source, usage pattern, velocity, and pressure were to remain the same as the conditions during the first study. The only change in the system was the installation of the new lead-soldered copper pipe test loops.

The pipe rack was connected to the public water supply on December 12, 1990. Flow rates through each test loopwere set at 1.0 gpm (3.8 L/min.). The pressure regulation valve was adjusted to maintain the operating water pressure at 40 psig (275.8 kPa). The programmable timer was set to cycle the water through six flowing and six standing cycles per day.

The timer operated on a schedule that was convenient for laboratory personnel and that enabled them to collect samples during the normal workday. A flowing sample was collected between 8:00 and 8:30 a.m., and the three standing


samples were collected at 4:30 p.m., after exactly 8 hours of stagnation. The study plans called for a higher sampling frequency during the first 40 days in order to produce data comparable with the first AWWARF study. The samples were collected during the first two tinier cycles, as illustrated by the following schedule.

Time Cycle7:30 a.m. on8:30 a,m. off4:30p.m. on5:00p.m. off7:30 p.m. on8:00 p.m. off10:30 p.m. onll:00p.m. off1:30 a.m. on2:00 a.m. off4:30 a.m. on5:00 am. off

The first samples were collected on December 17,1990, after the pipe rack had been in operation for 5 days. The sampling frequency varied from between one and five samples per week during the first 40 days to one sample every 7 to 10 days thereafter. The sampling procedure followed the strategy developed for the first AWWARF study (EES1990). Flowing samples were collected from aPVC sampling valve located ahead of the pipe test loops. This valve was flushed prior to collection of the flowing sample. Standing samples were collected from PVC sampling valves immediately following each pipe test loop.

For both standing and flowing samples, the first 100 mL of water from the sampling valve were collected fortemperature measurement. The water was allowed to flow continuously at approximately 100mL/minlhroughoutthesamplingprocess. The next 50 to 100 mL of water were collected hi glass vials for pH and dissolved inorganic carbon (DIG) measurements. The next 500 mL of sample were collected for trace metal determinations in apolyethylene bottle containing 1.5 mL of ultrapure nitric acid. A final 500 mL of sample were collected in anunpreserved polyethylene bottle for total alkalinity, ammonia, and chlorine residuals measurements.

The date, time, and water meter reading were recorded for each sampling event. Chlorine residuals and pH were measured immediately after all samples had been collected. Ammonia, total inorganic carbon, and total alkalinity were determined within 24 hours of sampling. Calcium, copper, lead, and zinc were determined whenever the sample backlog exceeded 15 to 20 samples.

The AWWARF pipe rack was in continuous operation for 393 days. Samples were collected on 70 occasions during the study period, and many analytes were analyzed in duplicate.


Corrosion Coupon TestingA pipe loop system developed by the U. S. Army Corps of Engineers'

Construction Engineering Research Laboratory (CERL) was installed in the AWWARF pipe rack in addition to the lead-soldered copper test loops. The CERL- PLS was designed to monitor water corrosivity and corrosionrates of metal materials by measuring the weight loss of corrosion specimens. Two types of corrosion specimens were utilized for these measurements: coupons and pipe inserts. The design and construction of the CERL-PLS is described fully in Lead Control Strategies (EES 1990) and elsewhere (Temkar et al. 1987,1989).

Because the ISWS routinely monitors water corrosivity, an inventory of copper, lead, and 50:50 lead-tin solder corrosion specimens was available for use during the study. Copper, steel, galvanized steel, and lead-soldered pipe inserts are produced in-house, and copper, steel, zinc, and lead coupons are purchased from a supplier. The CERL-PLS installed at the ISWS site would accommodate amaximum of four coupons and four pipe inserts. The plan was to install copper coupons, lead coupons, copper pipe inserts, and lead-soldered copper pipe inserts for selected periods during the proposed study. These materials were chosen to conform with the materials used to construct the pipe test loops. The first set of corrosion specimens was installed January 1,1991, approximately 2 weeks afterthe AWWARF pipe rack was placed in operation.

The corrosion specimens were removed and replaced with like specimens at convenient intervals to evaluate the effect of water corrosivity with time. The weight loss results for the corrosion study are reported in Appendix F.

Corrosion Treatment Studies_____________

Two utilities incorporated AWWARF test loops into their existing corrosion pipe racks: the Philadelphia Water Department and the New York City Bureau of Water Supply and Wastewater Collection. Both utilities had existing pipe racks that had been constructed to evaluate the impact of various treatments on the corrosion rates and metals leaching characteristics of selected materials. The construction and operation of these pipe racks (with emphasis on the AWWARF test loop sections of each rack) are described below.

Philadelphia Water Department

Pipe Rack ConstructionThreepiperackswereconstructedatPhiladelphia'sBaxterWTPtoevaluate

three water treatment schemes for reducing lead levels. Each rack consisted of six sections. The first section was based on the CERL pipe loop design. Two 1-ft (0.3-m)lengthsofl-in.(2.54-cm)nominaldiameterschedule80chlorinatedpolyvinyl chloride (CPVC) pipe were included in this first section to hold the two 4-in. (10.16-cm) lengths of steel pipe. The outside diameter of the steel pipe was designed to fit tightly inside the CPVC pipe to prevent water contact with the external wall of the steel pipe. Mild steel coupons were also housed in %-in. (1.9-cm) PVC schedule 40 pipe for comparison of corrosion rates.


The second, third, and fourth pipe sections were composed of coupons of home plumbing materials, i.e., lead coupons, and redundant sets of lead-soldered copper coupons. These sections were separated from the first by a three-way valve. A sampling valve was located at the end of each section for sample collection.

The fifth and sixth sections for each rack were composed of two flow-through AWWARFpipe loops connected in series. The first loop was made from lead and the second from copper with 50:50 lead-tin-soldered joints. These loops were placed at the end of Philadelphia's existing pipe rack, as shown in Figure 3.1. The lead loop was connected to the PVC pipe with dresser couplings. Both the lead loop and the lead-soldered copper loop were of a %-in. (1.9-cm) ID, with a total length of 15 ft (4.6 m) and an internal volume of approximately .34 gal (1.3 L).

The startup procedures for the A WWARF pipe loop section of the pipe rack consisted of (1) preconditioning the test loops according to recommendations developed by the ISWS from its hot water flushing study, (2) adjusting the flow rate through the loop to maintain operational consistency, (3) adjusting the chemical feed pump, and (4) passivating the loops for 7 days to establish aprotective film inside the loops, after which a lower maintenance dosage was sustained.

Chemical System DescriptionThe three treatment schemes applied to the racks consisted of pH adjustment

to 8.1 (the current treatment at the Baxter plant) and the addition of either a 1:3 or a 1:10 zinc orthophosphate inhibitor. The target inhibitor dosages are shown below.

Inhibitor dosage (mg/L)Maintenance Passivation

Chemical Treatment PO4 Zn PO,, ZnExisting treatment (pH 8.1) 00 001:3 zinc orthophosphate 0.36 0.12 1.44 0.481:10 zinc orthophosphate 1.20 0.12 3.30 0.33

The zinc orthophosphate chemical was supplied by a regional chemical supplier located in a suburb of Philadelphia. The chemical formulation of the inhibitors was proprietary; however, the supplier did provide the following information on its content:

Treatment Percent zinc (as zinc Percentphosphate scheme monosulfate) (as phosphoric acid)

1:3 zinc orthophosphate 8 24 1:10 zinc orthophosphate 3.3 33

The inhibitor feed solutions were mixed in a 55-gal (208-L) drum using effluent water from the Baxter plant. The solution was fed to the pipe racks using a positive displacement pump at a rate of 8 mL/min. This flow rate was determined during a 2-week startup period for the pipe racks. Flow rates less than 8 mL/min were


PHILADELPHIA WATER DCPMITUCNT COPPER LOOPS

«*WARFCOPPER VHTH

SOLOEREO JOINTS

Source: Courtesy of Philadelphia Water Department

Figure 3.1 Philadelphia pipe rack schematic

Table 3.1 Philadelphia Water Department water quality testing protocol, Baxter WTP pipe rackType of sample

OperationalMonitoringRunning samples

Standing samples(startup)

Standing samples(normal operations)

Parameter

P04PHFlowAverage flowPressureVisual check

HPCtColiformsfTotal CLPHTemperature

Unfiltered PbFiltered PbCuHPCfColiformstTotal CI2TemperatureP04

Frequency

1/d1/d1/d1/week1/d1/d

1/week1 /month1/week1/week1/week

1/week1/week1/week1/week1/week1/week1/week1/week

Number of sample locations*

303333

11131

1616366316

* Baxter WTP pipe racks contain a total of six loops per rack, two of which are AWWARF loopst HPC and coliform samples were checked weekly for 2 months, then monthly for 4 months; sampling was then discontinued due to

consistently low plate counts


too low for the pump, and higher flow rates created a pulse effect that introduced air bubbles into the loops. With the 8-mL/min flow rate, the 55-gal (208-L) drum solution lasted about 3 weeks.

Operation of the Pipe RacksWater came through each of the pipe racks in a continuous one-pass flow,

and the discharge was routed back to the treatment plant influent. Flow through the loop was controlled at 3 gpm (2.2 fps [0.67 m/s]) by use of a needle valve on the influent to the rack to ensure that maximum flow did not exceed 4 gpm (0.25 L/s). A pressure-regulating valve on the influent line maintained a water pressure of 16 to 24 psi (110.3 to 165.5 kPa).

The pipe racks were checked daily during and immediately after startup and approximately two to four times per week throughout the remainder of the study. Table 3.1 displays the operational and water quality sampling protocol implemented for the Baxter pipe racks. From January through September 1991, the following sampling protocol was followed. Each of the three pipe rack effluents was tested daily for orthophosphate concentration, pH, and residual chlorine. Once per week, each section of the pipe racks was shut off for 24 hours and standing samples were drawn from the effluent of each loop. From September through December 1991, the frequency of collection for standing samples was reduced to once every 2 weeks.

New York City Bureau of Water Supply and Wastewater Collection

Pipe Rack ConstructionNew York City constructed eight pipe racks; six were located at the Hillview

ReservoirforevaluationoftheCatskill Delaware supply.and two were located at the Jerome Park Demonstration Water Treatment Plant on the Croton supply. The pipe racks were acombination of the CERL corrosion rate loops and individual AWWARF test loops of lead, copper, and copper soldered with 50:50 tin-lead solder. Each of the CERL pipe racks contained four 3-in. (76.2-mm) pipe inserts of lead, copper, galvanized steel, and mild steel. Each rack also held 3-in. (76.2-mm) flat metal coupons of the same materials. The AWWARF test loops consisted of 45-ft (13.72 m) lead coils with a 1-in. (25.4-mm) ID, 60-ft (18.3-m) copper coils with a Vi-m. (12.7-mm)ID, and copper coils soldered at 20 joints with 50:50 tin-lead solder. Figure 3.2 displays the layout for the New York City pipe racks.

The startup procedures consisted of conducting hydraulic tests to check for tightness in pipe rack systems and chemical metering systems, establishing desired flow rates, eliminating air bubbles in chemical feed lines, and establishing the desired pH levels.

Chemical System DescriptionThe New York City pipe racks were used to evaluate several different

corrosion treatment options, as follows:


Pipe rack number Supply Treatment12345

Croton CrotonCatskill Delaware Catskill Delaware Catskill Delaware

6 Catskill Delaware

7 Catskill Delaware

8 Catskill Delaware

Zinc orthophosphate (pH 7.0) Control (no treatment) Control (no treatment) Caustic soda (pH 7.5) Zinc orthophosphate (pH 6.5,

then 7.0) Zinc orthophosphate and caustic

soda (pH 7.5) Blended orthophosphate and

caustic soda (pH 7.5) Blended orthophosphate (pH 6.5,

then 7.0)

Due to an oversight, the corrosion treatment study for pipe racks 5 and 8 was initiated at a pH of 6.5. The pH was adjusted to 7.0 using NaOH 2 months after the start of operations.

Target inhibitor dosages are shown below.

Passivation (mg/L) Maintenance (mg/L)Inhibitor PO, Zn PO, Zn

Zinc orthophosphate not available 1 not available .24 Blended orthophosphate 10 not available 2.5 not available

Operation of the Pipe RacksWater was allowed to flow continuously through the pipe racks at a rate of

2 gpm (7.6 L/min) through the corrosion rate loops and 1 gpm (3.8 L/min) through the AWWARF test loops. Biweekly, the flow was manually stopped and water was allowed to stand for a minimum of 16 hours in the test sections. Standing lead and copper levels were analyzed, as well as the following water quality parameters, which were measured during the initial months of the study:

lead and copperpHtemperatureturbidityspecific conductancechlorine residualdissolved oxygenalkalinityhardnesszinc

1/2

' TY

PE K

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TYPE

L C

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typ

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SAMPLE

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HEAT

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(TYP.)

PRES

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ourte

sy o

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ironcalciumsodiumorthophosphatetotal dissolved solidsheterotrophic plate countstotal colifonnstrihalomethanes (I/month)

With the exception of trihalomethanes, which averaged a 10-pg/L increase in treatments utilizing caustic soda addition, no changes of significance were observed in the first-draw sample for these parameters. With the exception of lead and copper, these parameters were removed from the sampling program after the initial months of the study because of the demands on the laboratory.

Distribution System Correlation Studies________

Three utilities conducted distribution system tap sampling concurrently with the operationofasingleAWWARF pipe rack that contained three replicate testloops of lead pipe or of copperpipe soldered with 50:50 tin-lead solder. These utilities also collected standing tap samples in the distribution system to be analyzed for lead and copper.

The Fort Worth Water Department constructed two pipe racks, one with three replicate lead test loops and the other with three replicate soldered copper test loops with50:50tin-leadsolder. Data from the copperpipe racks were correlated with distribution system monitoring data from an area of homes with 50:50 tin-lead- soldered copper pipe. The data from the lead pipe rack were correlated with data collected in an area of the distribution system that contained lead service lines. The Contra Costa Water District and the Portland Water Bureau constructed one pipe rack each, withthree replicate testloops of copper soldered with50:50 lead-tin solder. Home tap samples were collected from sites with 50:50 lead-tin-soldered copper pipe.

The pipe rack construction and operation and the distribution system sampling implemented by these three utilities are described below. To facilitate consistency in the construction of eachutility 's pipe rack, Economic and Engineering Services, Inc. (EES), procured all flow meters, sample cocks, pressure-regulating valves, totalizing water meters, and programmable timers and distributed them to each of the three utilities.

Finally, because of the large amount of data generated during this project, it was necessary for each utility to establish sample-tracking and data-handling procedures so thatthe data could eventually be interpreted. These procedures are also described in the following sections.


Contra Costa Water District

Pipe Rack Construction and StartupThe CCWD located its pipe rack at the Midhill Reservoir in the Martinez

district of its distribution system. This area was identified as including a number of homes that met the final Lead and Copper Rule' s targeting criteria for sites with lead- soldered copper pipes. A student intern assembled all materials and constructed the pipe rack except for soldering the copper test loops. A journeyman plumber was contracted for the copper joint soldering to better simulate the quality of plumbing found in the target homes. The completed pipe rack was mounted on the wall of a pump station that serviced the targeted area where the home tap samples were collected (see Figure 3.3). The entire construction process was completed in an 8-week period. The total amount of solder used for each.loop was 63, 61.6, and 58.9 g, respectively.

The startupprocedures forthe CCWDpipe rack consisted of preconditioning the test loops according to the recommended ISWS protocol, calibrating the rotameters for each loop, and collecting initial bacteriological samples.

Operation of the Pipe RackFlow. Flow through the pipe rack was maintained at 1 gpm (3.8 L/min)

through each of the A WWARF test loops (atotal of 3 gpm [11.4L/min] forthe entire pipe rack). The following on-off schedule was implemented:

Time Cycle7:30 a.m. on8:00 a.m. off4:30 p.m. on5:00p.m. off7:30 p.m. on8:00 p.m. off10:30 p.m. onll:00p.m. off1:30 a.m. on2:00 a.m. off4:30 a.m. on5:00 a.m. off

Water Quality Monitoring. The effluent from the pipe rack was sampled for both operational and corrosion parameters. The operational monitoring was completed on running samples of the influent to the pipe rack, and the corrosion monitoring was completed on standing samples from each test loop.


Figure 3.3 Contra Costa pipe rack

The operational parameters were measured once a week between 7:30 and 8:00 a.m. while water was flowing through the loops. The following parameters were analyzed:

• free and total chlorine• temperature• pH• alkalinity• calcium• specific conductance• ammonia• orthophosphate


• lead• copper• flowFirst-flush samples were also collected once per week at approximately 4:30

p.m., after an 8-hour standing time, and were analyzed for the same parameters. Approximately 25 mL were allowed to drain from the sample cock prior to sample collection to discharge the water in contact with the sample rack. A1 -L sample was then collected from each of the test loops.

Distribution System MonitoringSite Selection. The firststep inselecting sites forborne tap monitoring was

identifying a portion of the service area that met the first-tier criterion set forth in the final Lead and Copper Rule (i.e., homes withlead-soldered copper plumbing installed after 1983) and that would also provide an adequate location for placing the pipe rack. An area of the Martinez district served by a single 12-in. (30.48-cm) main was chosen as most likely to meet this criterion. Computer data records were thenused to identify the homes in the area built after 1982 and before the lead ban, which was implemented in 1987. At this point, public relations and education played a critical role in obtaining the cooperation of the citizens in the targeted area. Through several direct mailings andapublicneighborhoodmeetingchairedbythearea'selected representative to the district board of directors, a pool of potential target homes was established. Question naires on home plumbing materials were completed by residents who expressed an interest in participating in the study. This information, coupled withon-site inspections to verify solder type and plumbing conditions, was used to narrow the field to 80 homes.

Sample Collection Procedures. Home tap sampling began at the end of April 1991. Samples were collected at the homes at 6-week intervals, for a total of nine sample rounds. A note was sent out a week ahead of each scheduled sampling to remind the consumers of the date and request that they contact the water district should they have a time conflict. Sample collection was accomplished by the customer. Each sample set consisted of two samples to be analyzed for lead and copper (standing 250- and 750-mL samples). Bottles were delivered to the homes the Monday before the Tuesday morning sampling. With each set of sample bottles, the customer was given a written reminder of the sampling technique and handling instructions. Samples were picked up on the day they were collected and then preserved back in the laboratory.

Fort Worth Water Department

Pipe Rack Construction and StartupThe Fort Worth Water Department located its pipe racks at the Alta Mesa

and Como pump stations. The Alta Mesa Pump Station was the location of the lead- soldered copper pipe rack because this station serves an area of the distribution system that contains newer homes with lead-soldered copper plumbing. The Como Pump Station serves an older area of the Fort Worth system where lead service connections are known to exist The typical diameter of these lead connections was


% in. (1.9 cm); therefore, an AWWARF pipe rack containing %-in. lead test loops was constructed at this pump station.

The water department solicited bids from local plumbers for construction of its two AWWARF pipe racks. Appendix E contains a copy of the bid documents. These documents were prepared by water department staff from January 3 to January 17,1991;the bid opening occurred onJanuary 22,1991; and the selected contractor built the pipe racks between July 3 and July 25,1991. Although the entire process took approximately 6 months to complete, the actual pipe rack construction was accom plished in 16 working days. The total amount of solder applied to each of the replicate copper loops was 56,64, and 57 g, respectively. Figure 3.4 shows both the Como and Alta Mesa pipe racks.

The startup procedures for the Fort Worth pipe racks consisted of preconditioning the test loops according to the recommended ISWS protocol, calibrating the rotameters for each loop, and collecting initial bacteriological samples as well as operational parameters and lead and copper samples while water was flowing through the loops.

Operation of the Pipe RacksFlow. Flow through the pipe racks was maintained at 1 gpm (3.8 L/min)

through each of the AWWARF test loops(atotal of 3gpm [11.4 L/min] for each of the pipe racks). The following on-off schedules were implemented:

Como pipe rack Alta Mesa pipe rackTime Cycle mode Time Cycle mode

7:00 a.m. on 7:30 a.m. on8:00 a.m. off 8:30 a.m. off4:00 p.m. on 4:30 p.m. on4:30 p.m. off 5:00 p.m. off7:00 p.m. on 7:30 p.m. on7:30 p.m. off 8:00 p.m. off10:00 p.m. on 10:30 p.m. on10:30 p.m. off ll:00p.m. off1:00 a.m. on 1:30 a.m. on1:30 a,m. off 2:00 a.m. off4:00 a.m. on 4:30 a,m. on4:30 a.m. off 5:00 a.m. off

Water Quality Monitoring. The pipe racks were sampled for both operational and corrosion parameters. The operational monitoring was completed on running samples of the influent to the pipe racks, and the corrosion monitoring was completed on standing samples from each test loop.

The operational parameters were measured once a week at approximately 7:15 a,m. for the Como pipe rack and at 8:00 a.m. for the Alta Mesa pipe rack while water was flowing through the loops. The following parameters were analyzed:


Figure 3.4 Fort Worth pipe racks


Weekly parameters• free and total chlorine• pH• alkalinity• specific conductance• lead• copper• heterotrophic plate count• dissolved oxygen

Monthly parameters• calcium• ammonia• silicate• iron• zinc• color• total dissolved solids

First-flush samples were also collected once per week at 4:00 p.m. for the Como pipe rack and at 4:30 p.m. for the Alta Mesa pipe rack (i.e., after an 8-hour standing time) and analyzed for the following parameters:

• lead and copper• pH• alkalinity• free and total chlorine• calcium• dissolved oxygen• ammonia• silicate• iron• zinc• color• total dissolved solids

A1-L sample was then collected from each of the test loops.

Distribution System MonitoringSite Selection. To identify potential home tap sampling sites, the water

department started by using current maps displaying areas of newer development to indicate the potential for use of lead-soldered copper plumbing. Older maps, plus computer printouts of service connection material, helped to identify areas of the city with lead service connections. Once these areas were identified, the pipe racks were installed in nearby pump stations.

Infonnational flyers were mailed to residences in targeted areas to solicit interest in collecting home tap samples (see Appendix D). hi addition, water department personnel attended local homeowners associations and neighborhood advisory committee meetings to provide information on the project and help solicit customer participation. Questionnaires on plumbing materials were completed by


homeowners who agreed to participate. Sixty-five percent of the sites were inspected by utility personnel to verify the plumbing materials and determine the suitability of each house for inclusion as a tap monitoring site.

Sample Collection Procedures. Home tap sampling began in late September 1991 for the lead-soldered copper sites and in early October 1991 forthe lead connection sites. When the sites had been selected, customers received both written instructions and a visit from department personnel to inform them how to collect standing tap samples (see Appendix D). Samples were collected once amonth by the customers. For the lead-soldered copper sites, each sample set consisted of three samples to be analyzed for lead and copper (a running 1 -L sample and standing 250- and 750-mL samples). For the sites with lead connections, three 1-L samples were collected at the kitchen tap: one standing sample, one sample taken after a 1-minute flush, and one taken after a 2-minute flush. Samples were picked up and acidified within 3 hours of collection.

Portland Water BureauPipe Rack Construction and Startup

The Portland Water Bureau (the bureau) located its pipe rack at the Capital Highway Office Pump Station (see Figure 3.5). This pump station served an area of the distribution system that contained amajority of the bureau's home tap monitoring sites; i.e., homes with lead-soldered copper plumbing built between 1981 and 1983.

The bureau solicited bids from local plumbers for construction of its AWWARF pipe rack. These documents were prepared by bureau staff during January and February 1991 and were approved by the city on February 28,1991. No bids were received during the March through April acceptance period; therefore the bureau hired a small Female Business Enterprise (FEE) firm to construct the rack. The contractor built the pipe rack between May 23 and July 1,1991. The entire process took 6 months, with actual construction of the pipe rack completed in 28 working days.

The amount of solder used for each test loop was 29.1, 38.1, and 32.1 g, respectively. The contractor did not use the solder or flux that was provided for the study. Analysis of the solder by the Portland Water Bureau laboratory verified that it was 50:50 lead-tin.

The startup procedures forthe Portland pipe rack consisted of preconditioning the test loops, calibrating the rotameters for each loop, and collecting initial bacteriological samples. The rotameters on each test loop were calibrated using a bucket and stopwatch. This procedure was accomplished while water was flowing through the rack by closing the outlet valve for each loop below the sample tap and opening the sample tap to drain into the bucket The sample tap valve was then adjusted to obtain a rotameter reading near 1 gpm (3.8 L/min). After the rotameter reading had stabilized, a 1-gal (3.785-L) container was placed under the sample tap and the time required to fill me container was recorded. This time was checked against the rotameter reading.

Total coliform and heterotrophic plate count analyses were collected and analyzed during the first weekof operation to confirm that the pipe rack was free from bacterial contamination. Samples were collected both from the running influent and from each test loop after an 8-hour standing period.


Figure 3.5 Portland Water Bureau pipe rack


Operation of the Pipe RackFlow. The flow through the pipe rack was maintained at 1 gpm (3.8 L/min)

through eachof the AWWARFtestloops(atotalof 3 gpm [11.4L/min] forthe entire pipe rack). The following on-off schedule was implemented:

Time Cycle mode6:30 a.m. on7:30 a.m. off3:30 p.m. on4:00 p.m. off7:30 p.m. on8:00 p.m. off10:30 p.m. onll:00p.m. off1:30 a.m. on2:00 a.m. off4:30 a.m. on5:00 a.m. off

Water Quality Monitoring. The pipe rack was sampled for both operational and corrosion parameters once per week by water quality inspectors who were trained and experienced in sampling water quality and making field measurements. The operational monitoring was completed on running samples of the influent to the pipe rack, and the corrosion monitoring was completed on standing samples from each test loop.

The operational parameters were measured between 7:00 and 7:30 a.m. while waterwas flowing through the loops. The following data were collected on these running samples:

Field measurements and records date pHair temperature specific conductance dissolved oxygen timewater temperature flow totalizer reading free chlorine

Weekly laboratory analyses• alkalinity• copper• pH• lead


Monthly laboratory analyses colorammonianitrogen total phosphorus calcium zinctotal dissolved solids reactive phosphorus silica iron

After morning tests were completed, the water flow was shut off until standing samples were collected at approximately 3:30 p.m. Approximately SO mL of water were allowed to drain from the sample cock prior to sample collection. A 1-L sample was then collected from each test loop. The following parameters were analyzed:

Weekly parameters alkalinityfield pH, laboratory pH chlorine residual, field free chlorine colorwater temperature, air temperature copper and lead dissolved oxygen specific conductance

Monthly parameters• dissolved solids• reactive and total phosphorus• ammonianitrogen• silica• calcium• zinc• iron

Distribution System MonitoringSite Selection. Sites were initially screened for distribution system tap

sampling by reviewing applications for water service that had been filed in the customerpermitrecords between 1981 and 1983. (Oregon's lead solderbanwentinto effect hi 1984.) All single-family residences identified through this setofpermits were mailedaletterdescribingthesampUngprogram and inviting the residents'participation. A self-addressed stamped postcard was included for their response. Approximately 350 homes were contacted, and about 90 of these returned the postcards. Respondents were telephoned and asked the age of theirplumbing and the type of dwelling before an appointment was set to test the solder and demonstrate the sampling procedure. Fewerthan 80 homes were eligible for sampling after this screening, so some residents who had not returned postcards were contacted and asked to participate. Using this method, the bureau was able to obtain a total of 80 participants for home sampling.


Of these 80,30 homes were served directly by the supply tank where the pipe rack was located.

Sample Collection Procedures. Home tap sampling began in July 1991. Samples were collected once every 2 months over a 1-year period, for a total of six sample rounds. The sample collection was initially spread out over a 1 -month span, with 20 sites sampled each week. Starting with the second sampling round, 40 sites were sampled each week over a 2-week time span.

The sample bottles were shipped by United Parcel Service (UPS) to each home sampling participant during the week scheduled for their samples collection. Twenty bottles were shipped out each week at a cost of $2.18 per set of bottles, or atotal of $43.60 forthe entire shipment. Participants were contacted by phone before the sample bottles were shipped to notify them that the bottles would be arriving and that they were to collect samples that week. Volunteers participating in the home sampling portion of this study collected their own samples according to instructions provided by the bureau. Each sample set consisted of three samples to be analyzed for lead and copper (a running 1 -L sample and standing 250- and 750-mL samples).

The filled sample bottles were picked up as soon as possible after participants had collected their samples. Participants were asked to leave their samples outside the front door on the morning of the day they were collected for pickup by a city water quality inspector. The sample bottles provided to the volunteers did not contain acid preservative. Nitric acid was added by utility personnel after all samples were collected.

The bottles were submitted to the lab as blind samples. A separate random numberforsample tracking was assigned to each bottle. The random numbers (2,000 total) were generated on label stock with four labels per number. For each bottle shipped, one label was placed on the bottle, one on the outside of the shipping carton, and one at the corresponding address on a master document list with the names and addresses of all participants. Thus each participating address had a total of eighteen labels at the end of the project (three labels for six sample rounds). Each random number label on the master document was identified by the date on which the sample bottles were shipped and the type of sample, as follows:

no. 1 = 1-L sample no. 2 = 250-mL sample no. 3 = 750-mL sample

Each time the master document list was updated (i.e., whenever bottles were shipped to the homes), a computer record with the same information was also updated as a backup.

Chapter 4

Discussion and Analysis of ResultsThis chapter contains a discussion of the study results from each of the

participating agencies. The IS WS summary focuses on the pipe loop flushing study, water quality data and statistical evaluation, and finally, operating problems associated with the AWWARF pipe rack. Data from the remainder of the participating utilities are discussed and statistically evaluated, and then the pipe rack operations and any problems that may have occurred are summarized. The sections on Contra Costa, Fort Worth, and Portland also contain a summary of the distribution system data collection and correlation evaluation.

Illinois State Water Survey_______________

Test Loop Flushing Study

ResultsThe analytical results for the cold and hot water flushing study, as described

in Chapter 2, are shown in Table 4.1 and Figures 4.1, 4.2, and 4.3. The metal concentrations for the background samples (cold water flush) were abnormally high in all three pipe loops due to inadequate flushing of the building's plumbing system. The lead, copper, and zinc concentrations for the background samples collected during subsequent flushing events were found to be below the minimum detection limit for the metals. The concentrations reported in this section represent the values found in the bulk water drained from the test loop after it had stood approximately 20 hours in the loop.

The quantity or temperature of the water used to flush the lead-soldered coppertestloopsdidnothaveasignificanteffectonthecopperconcentrations found hi standing samples collected from the test loops (Figure 4.1). The three test loops produced equivalent results. Copper concentrations ranged from 0.27 to 0.41 rag/l and averaged 0.38 mg/L for all loops. These data compare favorably with the mean copper concentration of 0.43 mg/L observed during the 30-day study reported in Lead Control Strategies (EES 1990). The use of hot water (150 to 160°F [66 to 71°C]) instead of cold water to flush the pipe loops did not change the copper

91

to ^

Tabl

e 4.

1 Ef

fect

s of

flus

hing

pro

cedu

res

on m

etal

s co

ncen

tratio

ns fr

om le

ad-s

olde

red

copp

er tu

be te

st lo

ops

Flus

hing

con

ditio

ns

Sys

tem

Back

grou

nd(fl

owin

g sa

mpl

e)

Loop

1(s

tand

ing

sam

ple)

Loop

2(s

tand

ing

sam

ple)

Loop

3(s

tand

ing

sam

ple)

Flus

h te

mpe

ratu

re

Col

dH

otH

otH

ot

Col

dH

ot Hot

Hot

Hot

Col

dH

otH

otH

otH

ot

Col

dH

otH

otH

otH

ot

Dur

atio

nFl

ush

0.2

0.2

2.0

76.0 0.2

0.2

2.0

24.0

76.0 0.2

0.2

2.0

24.0

76.0 0.2

0.2

2.0

24.0

76.0

(hou

rs)

Tota

l

0.2

0.4

2.4

78.4 0.2

10.

42.

426

.410

2.4

0.2

10.

42.

426

.410

2.4

0.2

0.4

2.4

26.4

102.

4

Pb1

(M

9/L)

0.0

0.0

0.6

4.1

,631

.063

3.0

225.

096

.730

.8

,122

.045

1.0

157.

047

.616

.2

853.

044

0.0

258.

063

.9 8.1

Pb2

(H

9/L)

4.1

2.8

0.0

2.8

1,91

9.0

751.

022

8.0

40.0

14.1

1,26

8.0

473.

014

6.0

40.0

44.1

429.

036

8.0

184.

074

.810

.5

Met

als

Pb m

ean

(M9/

L)

2.0

1.4

0.3

3.4

1,77

5.0

692.

022

6.5

68.4

22.5

1,19

5.0

462.

015

1.5

43.8

30.2

641.

040

4.0

221.

069

.4 9.3

conc

entra

tions

of

Cu1

(m

g/L)

0.40

0.01

0.01

0.00

0.39

0.40

0.41

0.40

0.34

0.41

0.39

0.41

0.41

0.31

0.37

0.34

0.33

0.36

0.28

Cu2

(m

g/L)

0.44

0.01

0.01

0.02

0.36

0.36

0.41

0.41

0.36

0.40

0.39

0.41

0.43

0.36

0.34

0.45

0.41

0.36

0.27

repl

icat

e sa

mpl

es

Cu

mea

n (m

g/L)

0.42

0.01

0.01

0.01

0.37

0.38

0.41

0.41

0.35

0.40

0.39

0.41

0.42

0.33

0.35

0.40

0.37

0.36

0.27

Zn1

(mg/

L)

4.77

0.03

0.04

0.31

9.05

0.44

0.14

0.09

0.13

6.19

0.21

0.12

0.11

0.19

3.82

0.24

0.11

0.09

0.12

Zn2

(m

g/L)

4.41

0.02

0.03

0.34

9.35

0.41

0.13

0.08

0.11

4.92

.0.

180.

110.

110.

18

7.27

0.21

0.11

0.08

0.12

Zn m

ean

(mg/

L)

4.59

0.02

0.04

0.33

9.20

0.43

0.13

0.09

0.12

5.56

0.19

0.11

0.11

0.18

5.55

0.22

0.11

0.08

0.12

¥ •§ I 8

Not

e: C

old

= 55

-60°

F;H

ot =

150

-160

°F

Discussion and Analysis of Results 93

|G

1e1o1-1

U

10.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

1 - Cold water, 12-minute flush2 - Hot water, 12-minute flush3 - Hot water, 2-hour flush4 - Hot water, 24-hour flush5 - Hot water, 76-hour flush

1

m

2 3Flushing event

Figure 4.1 Effect of flushing on copper dissolution

Loop 1 Loop 2 Loop 3

N

1234Flushing event

Figure 4.2 Effect of flushing on zinc dissolution


*

81 si

1.9 1.8 1.7 1.6 1.5 1.4

1.21.1

10.90.80.70.60.50.40.30.20.1

01

1 - Cold water, 12-minute flush2 - Hot water, 12-minute flush3 - Hot water, 2-hbur flush4 - Hot water, 24-hour flush5 - Hot water, 76-hour flush

•,I

LOOP 2r Loop 3

Flushing event Figure 4.3 Effect of flushing on lead dissolution

dissolution significantly. The presence of soldering flux, which was at least a factor in the initial flushing events, did not appear to influence the copper content. Most copperzinc chloride minerals are readily soluble and were likely removed during the first few minutes of flushing.

Zinc residues were anticipated to be present in the pipe loops because aliquid flux containing zinc chloride was used in the soldering process when the loops were assembled. The waterused forflushingthe loops did contain very low concentrations of zinc because the building plumbing system was constructed from galvanized steel pipe. Afterthis background concentration was deducted, the remaining zinc content of standing samples was assumed to be an indication that some flux residue was still present in the pipe loops. As shown by Figure 4.2, flushing the pipe loops with cold water was not totally effective in removing the flux residue. The zinc content found in samples from Loop 1 was biased by inadequate flushing of the building system. ML the background zinc were subtracted out, results found for Loop 1 would be much closer to the zinc concentrations found for Loops 2 and 3. Flushing the pipe loops for 12 minutes with hot water had a significant effect on removing the zinc residue, reducing the zinc concentrations in standing samples by 95 percent compared to the cold water flush. Extending the hot water flushing time to 2 hours resulted in a further 40 to 60 percent reduction in zinc content. However, the zinc content was not reduced significantly with subsequent hot water flushing events of 24 and 76 hours.


Longer flushing times were needed to reduce the lead concentrations to less than 10 ug/L lead in standing samples collected from lead-soldered copper test loops. Each of the five flushing events reported in this study resulted in an additional reduction in the lead content, as shown by Figure 4.3. No conclusions can be drawn from these data about the effect of hot water flushing on the lead content found in standing samples. The hot water may or may not have reduced the time needed for the lead content to approach equilibrium concentrations within the pipe loops. In any event, hot water flushing did not have any obvious detrimental effects on the results. The lead content of Loop 1 may also have been biased by the galvanized steel plumbing during the cold water flush.

ConclusionsIn the earlier AWWARF study, visible evidence of an unidentified flux

residue remained in the lead-soldered copper pipe loops after the study was completed. It was found at that time that the residue was soluble inhotwater, and this solubility was the primary reason for investigating the use of hot waterto precondition soldered pipe loops used in corrosion studies.

The results of the flushing experiments indicated that hot water flushing was effective in removing the zinc contaminants remaining in lead-soldered copper pipe loops. The hot waterflushingdidnothaveanynoticeableeffectoncopperdissolutioa The experimental results also indicated that a longer flushing time was required to reduce lead contamination by soldered copper pipe loops after assembly.

This study indicates that lead-soldered copper tube loops should be flushed with 150 to 160°F (66 to 71°C) water for at least 24 hours before a monitoring program utilizing pipe loops inacorrosion study is initiated. Lead pipe loops may also benefit from extended flushing with hot water, although additional preconditioning studies are needed for lead pipe materials. In addition to removing contaminants, the hot water flushing tends to reduce the time requued for a corrosion equilibrium to be established between the metal materials and the water. This factor can appreciably reduce the time required to conduct a pipe loop study. If hot water is not available, cold water flushing should be used. Cold water will likely not be as effective as hot water, and longer flushing times will be needed.

Water Quality Monitoring and VariabilityA fundamental purpose of the AWWARF study at ISWS was to determine

the long-term variability in dissolution of lead, copper, and zinc from the three identical lead-soldered copper test loops. Other important water quality parameters were monitored to determine whether the test loops would respond in a similar manner should a change in water quality occur. To obtain the analytical data, one flowing water sample and three standing (8-hour) samples were collected from the AWWARF pipe rack on 70 occasions during the study. The pH, temperature, residual chlorine, dissolved inorganic carbon, and total alkalinity were determined immediately after sampling. Ammonium was determined within 24 hours, and calcium, lead, zinc, and copper were determined when a sufficient number of samples (20) had accumulated. Many of the determinations were made in duplicate. Approximately 2,800 total analytical measurements were made during the 393-day study period. For each sample collected, the mean value of the analytes is reported in Tables 4.2 through 4.5.


Table 4.2 Water quality of flowing samples collected ahead of lead-soldered copper tube loops, AWWARF model pipe rack, Illinois State Water Survey

Date sampled

12/12/9012/17/9012/18/9012/19/9012/20/9012/21/9012/27/9012/31/9001/03/9101/04/9101/07/9101/08/9101/09/9101/10/9101/11/9101/14/9101/15/9101/16/9101/17/9101/18/9101/22/9101/23/9101/24/9101/25/9101/29/9101/31/9102/07/9102/14/9102/19/9102/26/9103/15/9103/21/9103/29/9104/05/9104/12/9104/22/9104/26/9104/30/9105/06/9105/14/9105/21/9105/29/9106/06/9106/11/9106/20/9106/27/9107/02/9107/19/9108/08/9108/15/9108/20/9108/27/9109/06/91

Tempera- Duration ture (days) (°C)

056789

1519222326272829303334353637414243444850576469769399

107114121131135139145153160168176181190197202219239246251258268

15.014.614.414.612.812.314.512.311.512.412.212.812.512.411.012.912.612.811.510.212.312.710.811.010.912.511.011.011.610.511.412.014.213.216.217.716.119.115.716.917.219.119.619.920.821.922.122.422.622.221.021.2

pH

8.848.948.738.779.028.848.978.868.829.189.018.899.058.998.738.628.859.119.108.868.758.939.018.828.968.829.208.998.949.029.028.918.878.917.707.757.737.728.599.629.598.708.708.758.918.898.959.618.928.959.109.29

Total alkalinity

(mg/L)

110.9109.0109.9118.3114.3106.4116.1113.5114.3118.7119.4123.0118.2118.4125.1127.0123.5113.2115.7128.5129.0138.6126.3122.6118.0120.5122.4112.6119.5125.4118.5118.5119.6124.1234.6249.9264.9292.2136.2109.7111.4118.7119.5118.8118.6119.5121.0115.2125.4123.5124.8131.2

Free CI2 Total CI2

(mg/L) (mg/L)

0.900.610.900.591.100.960.000.000.00

0.000.000.000.000.280.440.520.120.240.941.040.861.240.861.220.820.640.400.700.480.400.370.601.330.680.000.000.000.000.000.000.000.00

0.380.000.000.281.241.201.260.00

0.920.841.040.741.281.141.781.641.82

2.082.122.101.882.202.021.842.122.082.141.982.102.301.941.962.191.801.601.541.051.601.120.701.330.681.001.421.031.971.860.940.180.660.480.381.721.840.281.241.201.260.32

NHS (mg/L)

0.84

1.371.39

1.441.291.301.37

1.471.351.13

1.341.271.191.361.381.361.421.381.020.13

0.95

1.14

1.13

1.10

1.06

1.14

DIG mgC/L

25.725.226.027.325.4

26.025.926.325.826.927.826.526.728.929.728.024.525.429.030.130.728.027.926.927.527.0

Pb (M0fl.)

bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl1.4bdlbdl1.1bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl0.9bdlbdlbdlbdl1.2bdl

Ca (mg/L)

12.213.312.612.112.513.512.212.914.411.312.912.612.012.112.613.113.210.611.312.113.312.612.112.512.215.814.513.413.314.415.113.313.313.943.562.451.531.7

9.411.411.710.813.717.817.016.316.313.716.416.013.5

Cu (mg/L)

bdl0.03bdlbdlbdlbdlbdl

0.050.05bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.090.03bdlbdlbdlbdlbdlbdlbdlbdlbdl

0.030.05bdlbdlbdlbdlbdlbdlbdlbdlbdl

0.090.07bdlbdl

0.100.03bdl

Zn (mg/L)

bdlbdlbdlbdlbdlbdlbdlbdl

0.04bdlbdlbdlbdlbdlbdlbdlbdlbdl

0.06bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.04bdlbdlbdl

0.470.080.050.05bdlbdlbdlbdl

0.030.04bdlbdlbdlbdl

0.030.03bdlbdl

(continues)

Table 4.2 (continued)

Date sampled

09/12/9109/17/9109/29/9110/03/9110/09/9110/15/9110/26/9110/30/9111/08/9111/14/9111/22/9111/27/9112/06/9112/11/9112/19/9112/23/9112/30/9101/09/92

SamplingMeanStandardVariance

Duration (days)

274279291295301307318322331337345350359364372376383393

events

deviation

Tempera ture (°C)

21.619.619.719.521.720.919.618.516.515.816.114.619.319.518.512.411.713.0

70.0015.583.84

14.74

PH

9.329.659.99

10.038.968.678.768.578.618.708.748.868.578.759.149.219.258.86

70.008.910.410.17

Total alkalinity (mg/L)

131.0132.2133.7133.5113.6114.5112.7113.1101.9117.4117.2122.4121.7114.2114.5119.699.8

119.4

70.00127.5333.90

1,149.18

Freeci,

(mg/L)

0.000.000.000.000.000.000.00

1.961.820.921.280.880.060.000.000.00

66.000.460.520.27

Total CI2 (mg/L)

1.561.561.620.980.760.700.86

1.961.820.921.480.921.301.481.881.44

67.001.410.560.31

NH, DIG (mg/L) mg C/L

1.211.221.031.041.271.111.03

0.00

0.000.631.051.031.08

39.00 26.001.10 27.120.35 1.560.12 2.43

Pb (ug/L)

1.4bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

70.000.100.480.23

Ca (mg/L.)

13.913.914.013.813.712.913.213.116.114.013.713.712.010.910.712.412.012.4

69.0015.208.55

73.07

Cu (mg/L)

0.09bdlbdlbdlbdl

0.050.09bdlbdlbdlbdlbdlbdl

0.070.06bdlbdlbdl

70.000.000.040.00

Zn (mg/L)

bdl0.03bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

70.000.020.060.00

bdl = below detection limit; i.e., Pb< 0.76, Cu< 0.025, Zn< 0.025

The analytical data indicate that a major change in the water quality took place on April 22 and continued through May 6, 1991, at the ISWS site. On investigation, the local utility reported that an equipment failure at the 8-mgd West WTP was responsible for the change. Lime softening was discontinued at this plant on April 17 and did not resume until May 14. The change in water quality occurred in the distribution system served by the West plant; the water quality produced and distributed by the other treatment plants did not change significantly. Because the ISWS site is primarily served by the West plant; a substantial change occurred in calcium, total alkalinity, and pH during this period. This change in water chemistry had a remarkable effect on the copper and lead concentrations found in the standing samples collected from the lead-soldered copper test loops.


Table 4.3 Water quality of standing samples from lead-soldered copper test Loop 1, AWWARF model pipe rack, Illinois State Water Survey

Date sampled

12/12/9012/17/9012/18/9012/19/9012/20/9012/21/9012/31/9001/03/9101/04/9101/07/9101/08/9101/09/9101/10/9101/11/9101/14/9101/15/9101/16/9101/17/9101/18/9101/22/9101/23/9101/24/9101/25/9101/29/9101/31/9102/07/9102/14/9102/19/9102/26/9103/15/9103/21/9103/29/9104/05/9104/12/9104/22/9104/26/9104/30/9105/06/9105/14/9105/21/9305/29/9106/06/9106/11/9106/20/9106/27/9107/02/9107/19/9108/08/9108/15/9108/20/9108/27/9109/06/9109/12/91

Tempera* Operating ture

days °C

056789

19222326272829303334353637414243444850576469769399

107114121131135139145153160168176181190197202219239246251258268274

19.719.921.020.021.521.022.320.120.721.820.619.520.420.320.219.821.420.119.620.220.721.222.621.220.222.819.720.820.522.721.323.220.921.523.822.821.623.522.122.622.223.223.223.123.524.324.123.623.123.423.623.9

PH

8.848.888.688.709.488.958.778.749.008.888.848.988.948.708.548.789.028.978.808.628.878.898.888.818.738.968.948.878.958.888.848.738.857.697.757.757.768.549.579.508.668.698.728.898.878.939.598.918.959.049.288.99

Total Cla (mg/L)

0.080.050.070.040.080.540.060.060.040.040.040.100.240.080.080.080.060.100.060.050.060.120.100.080.040.020.080.020.020.030.060.040.020.000.000.040.040.100.080.040.020.040.00

0.060.000.000.000.000.000.08

NH(mg/L)

0.59

1.351.35

1.391.241.301.33

1.471.351.11

1.321.261.271.311.321.321.411.361.060.13

0.94

1.131.030.95

1.081.01

1.05

1.071.16

DIG mgC/L

25.8

25.927.625.124.725.826.326.327.028.126.526.628.929.828.024.825.228.829.731.227.827.726.627.627.0

Pb (M9VL)

1.81.21.11.81.74.31.91.21.71.51.81.21.51.51.0bdlbdl0.91.11.51.31.41.3bdlbdl1.5bdl1.0bdlbdlbdlbdlbdl7.6

17.112.49.2bdl1.01.8bdl8.12.42.91.61.72.5bdl4.9bdlbdl1.4

Ca (mg/L)

12.313.014.312.012.412.213.014.012.412.912.611.912.112.513.412.811.111.212.513.014.312.012.412.115.214.413.513.314.515.113.813.514.140.545.753.731.9

8.612.211.411.013.117.714.617.216.713.316.417.013.314.0

Cu (mg/L)

0.290.290.430.300.220.300.360.380.350.400.500.470.430.520.580.420.390.360.490.430.460.470.370.340.360.300.280.310.260.240.290.300.301.861.821.931.950.370.190.320.220.180.16

bdl0.180.060.160.180.150.160.181.59

Zn (mg/L)

bdlbdl

0.04bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.04bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.060.070.060.07bdlbdlbdl

0.05bdl

0.09bdlbdl

0.04bdl

0.05bdl

0.03bdlbdl

(continues)

Date sampled

09/17/9109/29/9110/03/9110/09/9110/15/9110/26/9110/30/9111/08/9111/14/9111/22/9111/27/9112/06/9112/11/9112/19/9112/23/9112/30/9101/09/92


Operating days

279291295301307318322331337345350359364372376383393

events

deviation

Tempera ture °C

21.624.824.625.122.122.121.624.922.623.223.824.623.023.923.424.723.8

6922.13

1.582.49

pH

9.609.99

10.039.448.638.728.598.458.648.728.768.418.749.039.209.118.71

698.860.420.17

Total Cl, (mg/L)

0.040.180.080.060.020.04

0.040.040.030.080.040.100.460.140.08

650.070.090.01

NH DIG (mg/L) mgC/L

1.191.031.031.231.141.011.000.00

1.110.940.991.00

41 251.10 27.160.29 1.630.09 2.66

Pb(ug/L)

3.02.51.30.81.0bdlbdl1.80.80.9bdl1.1bdlbdl1.31.1bdl

691.812.888.31

Ca (mg/L)

14.013.513.713.713.513.313.215.313.713.413.712.411.110.411.111.712.7

6814.977.42

55.08

Cu (mg/L)

0.290.210.300.210.460.450.210.300.220.220.220.350.180.220.180.220.28

690.410.410.17

Zn (mg/L)

0.04bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

690.010.020.00

bdl = below detection limit; i.e., Pb < 0.76, Cu < 0.025, Zn < 0.025

Figure 4.4 illustrates the sharp increase in copper dissolution that occurred with the change in water quality. The copper concentration exceeded the MCL (1.3 mg/L Cu) in all the standing samples collected when the West WTP was notoperating and was being repaired. When treatment was reinstated, the copper concentration decreased just as sharply to the level observed previous to the upset in water quality. The three test loops reacted identically in copper dissolution during the upset period and throughout the study. The dissolution of copper was continuous and did not decrease significantly with time of exposure. However, the chlorination practices of the water utility had an impact on the copper content in standing samples. As in the previous AWWARF study, copper concentrations increased slightly when the utility changed from a free chlorine to a combined chlorine disinfection program. The cycling of copper concentrations between 0.2 and 0.5 mg/L was a result of this variation in chlorine concentration and speciation. The chemical interaction between chlorine and copper was also evident, as both free and combined chlorine residuals were dissipated within the 8-hour interval during which water was standing hi the copper test loops.



Date sampled

12/12/9012/17/9012/18/9012/19/9012/20/9012/21/9012/31/9001/03/9101/04/9101/07/9101/08/9101/09/9101/10/9101/11/9101/14/9101/15/9101/16/9101/17/9101/18/9101/22/9101/23/9101/24/9101/25/9101/29/9101/31/9102/07/9102/14/9102/19/9102/26/9103/15/9103/21/9103/29/9104/05/9104/12/9104/22/9104/26/9104/30/9105/06/9105/14/9105/21/9105/29/9106/06/9106/11/9106/20/9106/27/9107/02/9107/19/9108/08/9108/15/9108/20/9108/27/9109/06/91

Duration (days)

056789

19222326272829303334353637414243444850576469769399

107114121131135139145153160168176181190197202219239246251258268

Tempera ture (°C)

19.719.820.520.021.420.522.620.220.621.620.419.620.320.220.019.921.620.119.620.020.721.122.821.220.323.019.820.820.722.621.323.120.821.323.622.721.623.322.122.522.423.023.423.123.424.324.024.223.223.423.5

pH

8.848.888.698.728.998.988.828.779.008.898.849.008.968.708.568.769.038.978.828.648.888.928.768.838.758.988.968.888.968.908.858.758.857.717.787.757.768.559.579.558.668.698.728.888.878.949.588.908.959.059.28

Total CL (mg/L)

0.140.030.070.040.060.500.060.060.080.040.040.100.040.080.100.080.060.100.060.070.040.030.020.040.040.040.060.020.020.100.100.100.04NDND

0.020.020.080.100.020.040.02NDND0.080.00NDNDNDND0.10

NH (mg/L)

0.60

1.341.44

1.381.261.311.39

1.471.381.10

1.241.231.341.341.301.381.341.040.13

0.95

1.110.920.94

1.040.99

DIG mgC/L

25.825.525.927.725.624.626.126.326.426.428.026.426.528.629.927.924.525.429.029.331.228.027.826.727.526.8

Pb(ug/L)

1.40.9bdl1.41.21.91.71.01.01.51.71.11.31.2bdlbdlbdlbdl1.10.91.11.61.0bdlbdl1.3bdlbdlbdlbdlbdlbdlbdl4.27.45.59.2bdl1.01.84.0

bdl1.2bdlbdlbdlbdlbdlbdl1.5

Ca (mg/L)

12.313.514.211.912.312.712.413.812.412.912.811.911.912.613.612.611.211.112.313.514.211.912.312.314.714.313.313.414.615.113.213.313.542.444.754.331.215.49.0

11.111.211.512.518.314.718.817.316.016.116.413.5

Cu (mg/L)

0.270.280.280.310.260.290.330.330.300.390.480.450.370.490.410.390.360.330.450.450.340.410.380.330.320.250.230.320.260.260.260.280.291.771.791.841.880.360.170.320.240.190.16

0.160.160.080.150.160.22

Zn (mg/L)

bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.060.060.050.06bdlbdlbdl

0.06bdlbdlbdlbdlbdlbdlbdl

0.03bdlbdl

(continues)

Date sampled

09/12/9109/17/9109/29/9110/03/9110/09/9110/15/9110/26/9110/30/9111/08/9111/14/9111/22/9111/27/9112/06/9112/11/9112/19/9112/23/9112/30/9101/09/92


Duration (days)

274279291295301307318322331337345350359364372376383393

events

deviation

Tempera ture (°C)

24.021.424.624.625.022.322.221.424.822.423.124.024.523.224.523.024.623.8

6922.10

1.602.56

pH

9.009.619.99

10.048.958.648.738.608.488.648.718.778.428.749.049.219.128.74

698.850.400.16

Total CL (mg/L)

0.080.180.040.040.040.04

0.060.020.080.100.030.060.480.140.06

660.070.080.01

NH DIG (mg/L) mg C/L

1.131.201.021.031.201.051.011.010.00

1.001.031.020.99

38 261.09 27.060.31 1.590.09 2.54

Pb (ug/L)

bdlbdl1.71.31.0bdlbdlbdl .0.9bdlbdlbdlbdlbdlbdlbdlbdlbdl

680.932.034.13

Ca (mg/L)

14.013.613.513.713.713.113.313.215.313.414.013.412.410.710.911.711.712.4

6915.027.44

55.40

Cu (mg/L)

0.150.260.240.260.350.410.270.230.290.210.220.250.320.190.210.130.230.27

670.380.370.14

Zn (mg/L)

bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

690.010.030.00

bdl = below detection limit; i.e., Pb< 0.76, Cu< 0.025, Zn< 0.025 ND = no data

The lead content of standing samples also increased dramatically during the upset in water quality, as shown in Figure 4.5. Two of the twelve samples exceeded 10 ug/L lead, whereas six samples contained from 5 to 10ug/L lead. There was much more variability between the three test loops in the lead data than was observed in the copper data during the change in water quality. Because lead solder was the only source of lead within the AWWARF pipe rack, the differences in lead content of the standing samples were likely due to the small and uncontrollable differences in the solder exposure within the test loops. The lead dissolution became somewhat more unstable after the change in water quality. Three to four months of operation were required before the lead concentrations were reestablished atthe low levels observed prior to the upset in water quality. Chemical reactions between lead and chlorine did not appear to be a significant factor contributing to lead dissolution in the previous AWWARF study and were not evident in this study.

The abrupt increase in both copper and lead concentrations was obviously due to the change in water quality. Of the monitored chemical parameters, the most significantchanges occurred in thepH, calcium, and total alkalinity dataforthe water supply. Based on previous analytical data, it is likely that less significant changes



Date sampled

12/12/9012/17/9012/18/9012/19/9012/20/9012/21/9012/31/9001/03/9101/04/9101/07/9101/08/9101/09/9101/10/9101/11/9101/14/9101/15/9101/16/9101/17/9101/18/9101/22/9101/23/9101/24/9101/25/9101/29/9101/31/9102/07/9102/14/9102/19/9102/26/9103/15/9103/21/9103/29/9104/15/9104/12/9104/22/9104/26/9104/30/9105/06/9105/14/9105/21/9105/29/9106/06/9206/11/9106/20/9106/27/9107/02/9107/19/9108/08/9108/15/9108/20/9108/27/9109/06/91

Duration (days)

056789

19222326272829303334353637414243444850576469769394

107114121131135139145153160168176181190197202219239246251258218

Tempera ture

19.719.820.520.021.020.622.420.120.521.420.219.420.120.019.819.921.519.819.620.120.620.922.521.120.522.919.820.920.922.521.223.120.921.323.622.621.623.322.122.522.423.123.423.123.424.324.023.723.023.423.5

PH

8.868.898.698.718.998.978.818.769.018.908.858.998.998.708.568.769.028.978.838.648.878.928.788.848.758.978.968.888.968.918.868.758.877.727.787.757.768.559.579.538.669.198.728.888.888.949.598.908.969.159.29

Total CI2 (mg/L)

0.080.040.070.060.060.410.080.040.060.040.060.080.060.080.080.080.100.120.040.050.040.060.040.080.060.040.060.020.040.120.080.060.04NDND0.020.040.040.500.020.020.04NDND0.10NDNDND

ND0.08

NH

0.55

1.371.42

1.401.281.311.34

1.531.341.11

1.331.261.261.341.331.351.371.321.040.11

0.94

1.091.040.90

1.01

1.05

DIG mg C/L

25.725.426.027.625.224.626.126.226.326.828.026.626.629.029.728.024.725.428.829.531.228.028.226.627.527.0

Pb

0.8bdlbdl1.60.92.11.81.11.41.52.11.11.11.3bdlbdl1.2bdl1.11.91.51.61.70.91.01.4bdlbdlbdlbdlbdlbdlbdl2.25.03.52.6bdlbdl1.2bdlbdl0.80.9

5.0bdl1.5bdlbdl2.7

Ca (mg/L)

12.013.014.112.111.712.612.414.412.512.812.611.811.912.313.512.511.011.212.013.014.312.111.712.414.314.513.513.314.515.013.313.314.142.344.753.231.215.38.6

12.211.310.712.319.015.315.917.615.015.816.813.3

Cu (mg/L)

0.24bdl0.310.280.220.300.300.340.320.390.440.390.400.500.400.310.360.340.400.420.290.400.360.310.320.260.280.300.250.240.240.260.271.761.761.811.760.390.180.320.230.200.140.210.200.160.180.090.160.180.23

Zn (mg/L)

bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.03bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

0.060.060.050.03bdlbdlbdlbdl

0.03bdl

0.030.03bdlbdlbdl

0.03bdlbdl

(continues)

Date sampled

09/12/9109/17/9109/29/9110/03/9110/09/9110/15/9110/26/9110/30/9111/08/9111/14/9111/22/9111/27/9112/06/9112/11/9112/19/9112/23/9112/30/9101/09/92


Duration (days)

274279241245301307318322331337345350359364372376383393

events

deviation

Tempera ture

23.821.424.424.524.822.222.221.624.922.423.023.924.923.224.623.024.623.9

6922.05

1.612.59

PH

9.009.619.99

10.048.958.648.738.608.508.658.718.778.438.759.059.229.128.79

698.860.410.17

Total CI2 (mg/L)

0.190.090.080.060.04

0.080.020.060.060.060.140.660.160.06

640.080.110.01

NH DIG (mg/L) mg C/L

1.141.201.201.061.221.121.021.010.00

0.800.960.971.01

39 261.11 27.090.31 1.610.10 2.59

Pb (M9/L)

0.9bdl2.1

1.1bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

670.911.291.66

Ca

13.214.013.813.713.613.313.213.315.713.014.013.712.310.710.712.011.712.4

6914.937.37

54.28

Cu (mg/L)

0.150.290.140.300.360.380.240.220.280.210.230.250.360.200.190.150.240.27

690.360.360.13

Zn (mg/L)

bdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdlbdl

690.010.020.00

bdl = below detection limit; i.e., Pb < 0.76, Cu < 0.025, Zn < 0.025 ND = no data

occurred in the chloride, sulfate, and silica concentrations, which were notmonitored. The observed pH varied throughout the study, as shown by Figure 4.6. A sharp drop hi pH occurred near day 131, coinciding with the sharp increase in lead and copper concentrations reported previously. After the low pH excursion, pH control was erratic and tended to exceed the optimal pH control range of 8.6 to 9.0. The decrease hi pH from approximately 8.8 to 7.8 is considered the major factor contributing to the high copper and lead concentrations. Mineral dissolution is increased at the lower pH. Standing samples from the pipe test loops exceeded the lead and copper action levels during the 3-week upset hi water quality. An indication of increased zinc dissolution was also observed; zinc was detected hi the standing samples during the low pH excursion. Zinc concentrations were normally below the analytical detection limit, although galvanized steel plumbing is used throughout the ISWS building system.

; 04 Development of a Pipe Loop Protocol

Loop 1

+ Loop 2

D Loop 3

300400

Duration of study (days) Figure 4.4 Copper in standing samples

0——0 Loop 1

+ Loop 2

D Loop 3

100 ~" 300


400

Figure 4.5 Lead in standing samples


10.210.09.89.69.49.29.08.88.68.48.28.07.87.6

0 I 100

200300

400

Duration of study (days) Figure 4.6 Variation of pH of samples during study

Statistical Evaluation of the Trace Metal DataThe analytical results for the study are summarized in Tables 4.2 through

4.5. Low-level concentrations are presented as being below the detection limit (bdl) of the method, and mean values are reported for replicate measurements. However, the actual results of a measurement, including negative values, were used in the statistical summary presented with each table and in the statistical evaluation of the analytical data. Negative values were the result of instrument noise and data variabili ty at concentrations below the detection limit of the analytical method. In the statistical evaluation of the data, the actual results were used rather than a zero value or a bdl value.

The trace metal results for the standing samples were statistically compared to determine whether the dissolution of copper, lead, and zinc was me same for all three test loops. An ANOVA procedure was used to evaluate the trace metal data. A personal computer and appropriate software were utilized to do the statistical analysis. The sample population consisted of 204 analytical measurements for each metal that were equally distributed into three data sets, one for each test loop. For each metal, the ANOVA program computed the variance for the mean concentrations of the three data sets and the variance for the concentrations within each data set The ratio of these two computed variances, known as the F ratio, was compared with an F value derived from probability tables and based on a specified level of significance (p level ^ .05). The result of this comparison indicates whether the population means are significantly different for the three data sets. For the copper and zinc analytical


data, the ANOVA results indicated that there was no significant difference in the population means for samples collected from the three test loops. These results statistically confirm that the copper and zinc levels of standing samples were the same for all three lead-soldered copper test loops.

However, a significant difference was detected by the ANOVA evaluation of the lead data from the three test loops. Furthermore, a nonparametric Kruskal- Wallistestofthedataindicatedthatthe results forLoop 1 were significantly different from the results for Loops 2 and 3. A significant difference was also found in the lead data by the ANOVA evaluation during the previous AWWARF study of lead- soldered copper test loops. The mean lead concentrations for samples collected from the three loops were 1.1,3.5, and 2.0 ug/L during the previous 30-day study and 1.9, 0.9, and 0.9 ug/L during the current 393-day study. The differences in the mean lead data represent very low concentrations and approach the detection limit of the analytical method. Although the variability in the analytical resultsmay be statistically significant, the lead concentrations in this particular study were probably below a level sufficientformaking reliable decisions ontreatmentstrategies, water corrosivity, or other applications of lead-soldered copper test loops.

ISWS Pipe Rack Operating ProblemsDuring the ISWS study, the pipe rack operated continuously for 393 days

without difficulty. The only complication noted was a pressure increase within the testloops when water was notflowingthrough the loops. This increase was attributed to a very small leakage of water through the pressure-reducing valve (PRV) that allowed the water pressure in the test loops to equal the pressure of the water supply. During the flowing events, the water pressure immediately reverted to the regulated pressure (40 psi [275.6 kPa). The flow rate through the pipe loops was not affected by the pressure change, requiring only small and infrequent adjustments during the study. The increase in water pressure when water is standing in the test loops is actually beneficial because the conditions within the test loops will more accurately reflect conditions in the actual water supply.

One waterutility using the AWWARF pipe rack (butnot participating in this study) reported that air was accumulating in the test loops and that water flow rates were difficult to control. It was determined that the water pressure was reduced within the test loops due to a change made by the utility that departed from the original AWWARF design. Itis very importantmatthe water pressure within the AWWARF pipe rack be maintained above the pressure necessary to keep any dissolved gases in solution. The solenoid shutoff valve was installed on the outlet piping to ensure that water pressure was maintained in the pipe test loops at all times. Water utilities with high levels of dissolved gases may need to adjust the PRV pressure to a setting very close to the distribution system pressure to minimize degassing problems. Gas pockets will disrupt the flow distribution between test loops. When air pockets are suspected, a schedule should be established to periodically increase the flow rate through each test loop to flush out the air.


Treatment Evaluation Studies________________

The purpose of the pipe rack operations at Philadelphia and New York City was to evaluate the impact of various treated water quality conditions on the corrosion of lead and copper in order to optimize corrosion control treatment. AWWARF test loops were incorporated into these pipe racks, and the following discussion summarizes the data and evaluations from these test loops only.

Philadelphia Water DepartmentWater Quality Data Summary and Statistical Evaluation

The purpose of the AWWARF portion of the Philadelphia corrosion study at the Baxter WTP was to evaluate the reduction in lead and copper levels in two different treatment trains. These reductions were evaluated for both lead and lead- soldered copper loops. Metals levels were measured from 1-L, 24-hour standing samples for three different conditions:

1. control water quality at a pH of 8.12. zinc orthophosphate at a dosage of 1.2 mg/L PO4 and a pH of 8.0

(1:10 treatment)3. zinc orthophosphate at a dosage of 0.36 mg/L PO4 and a pH of 8.0

(1:3 treatment)Each of these conditions was applied to one lead loop and one copper loop

soldered with 50:50 lead-tin solder. Samples were collected weekly for 33 weeks and approximately twice per week for the remainder of the 48-week study period. Samples of 1 L volume were collected, of which 500 mL were used for pH and chlorine residual analyses and 500 mL were used for filtered and unflltered lead and copper analyses. When colifonn analyses were performed (once per month), 250 mL were used for bacteriological analyses, 500 mL for pH and chlorine residual, and the remaining 250 mL for lead and copper analyses. The analytical data are discussed below for each pipe loop material.

Lead Loops. Total standing lead levels were measured on 37 samples from the control loop and on 38 samples from each of the treated loops over period of 48 weeks from January 1 through Decembers, 1991. These data are displayed hi Table 4.6 and Figure 4.7a and are summarized below.

Number of Treatment samplesControl 1:10 1:3

37 38 38

Weeks 1-48, lead levels (ug/L)

Mean1,209 803 669

Median352 191 170

Minimum

197 13 75

Maximum

19,700 12,580 8,300

Range

19,503 12,567 8,225

The control loop as well as the treated loops exhibited a wide range of lead levels with significant outliers observed (i.e., lead values approximately 50 times greater than median values), and the distribution of these data was highly nonnormal.


Table 4.6 Water quality of standing samples from AWWARF lead loops, Philadelphia Water Department, Baxter WTP

Date

01/10/9101/17/9101/24/9101/31/9102/07/9102/14/9102/21/9102/28/9103/07/9103/14/9103/21/9103/28/9104/04/9104/11/9104/18/9104/25/9105/02/9105/09/9105/16/9105/23/9105/30/9106/06/9106/13/9106/20/9106/27/9107/11/9107/18/9107/25/9108/01/9108/08/9108/15/9108/22/9109/10/9110/17/9110/24/9111/07/9111/21/9112/05/91

Sampling eventsMeanStandard deviationVariance

Week

123456789

1011121314151617181920212223242527282930313233364142444648

Control

417300239

262914197

1,082338281237274400270428275292561372320450290510

1,060410340450390310260480201

11,300404352198

19,700640

381,2103,557

12,652,000

Standing lead levels,

1:10 treatment

5,180229175456198

1,354238

12,580324412

1,256168

1,18841823916272

53418410714698

470640280

3967402828361752

2971825

2,74013

38803

21754,731,124

(MS/L)

1:3 treatment

911419170344220164196157181163142

1,974141152138121

1,102155221

, 200230164300350

93350201116133

8,30011775

171793119156159

6,300

38669

16402,689,250

"Ora

20,000

16,000

12,000

8,000

4,000

0

-4,0000

20,000

16,000

12,000

13 8,000

% 4,0001—J

0

-4,000,

10

Control loop

20 ' 30 Week

40

20,000

16,000

50

1:10 loop

0012,000

8,000<u

4,000

-4,000(

1:3 loop

10 20 30 Week

40 50

"0 10 20 30 40 50.Week

Figure 4.7a TQtal lead levels, weeks 1 through 48, Baxter lead loops

These spurious lead levels were seen at different times during the operation of the pipe racks, not just early in the study when initial high lead levels might be expected prior to stabilization of the corrosion process. By evaluating the trend in lead levels over time, an estimate can be made as to whether the lead levels stabilized and at what point during the study this stabilization occurred. The data collected after this point in the study can then be used to evaluate whether there was a significant difference hi lead levels between the control and the treated loops; i.e., whether the treatment had a significant effect on metals levels. Figure 4.7a displays the estimated trend lines for the lead levels from all three lead loops. Lead level data from the control loop and the 1:3 treated loop both appearto have slightly positive trends, indicating that lead levels were increasing during the study period. The 1:10 treated loop displays a slightly negative trend. The positive trend in the control loop and the 1:3 treated loop is probably due to the high lead levels measured after week 30 of the test. The presence of these extremely highlead levels makes itdifficultto determine when the lead levels stabilized; however, when the data are reviewed at a smaller scale (Figure 4.7b), it appears that levels settled down somewhat after week 25, particularly in the 1:10 treated loop. Data from weeks 25 through48 were used to evaluate whetherthere was a significant difference in lead levels measured between the control loop and the treatedloops. Given the relatively small numberof samples taken between weeks 25 and 48 (14 samples total), exclusion of the outliers may not be appropriate in this situation. For example, approximately 10 percent of the data would have to be excluded from the 1:3 loop if outliers were rejected in the analysis. The lead level data from weeks 25 through 48 are displayed in Figure 4.8 and are summarized below.

Weeks 25^48, lead levels (ug/L)

TreatmentControl 1:10 1:3

rNiuuuci uisamples

14 14 14

Mean2,531 263

1,221

Median397.0 37.5 162.0

Minimum198 13 75

Maximum19,700 2,740 8,300

Range19,502 2,727 8,225

The mean and median lead levels for both the l:10andthe 1:3 treated loops appear to be significantly lower than those of the control lead levels for weeks 25 through 48. The range of lead levels measured during this time for both treatments is also narrower than the range of lead levels from the control group. A nonparametric Wilcoxon matched pairs test was performed on these lead level data to evaluate whether there were statistically significant differences between the lead levels measured from the control lead loop and from the treated lead loops. Because of the small sample size and the presence of outliers, a standard parametric test such as a t test of mean differences would be ineffective. The Wilcoxonmatched pairs analysis indicates that there is a significant difference (at the p < .05 or 5 percent level) between the lead levels measured from the control and the 1:10 treated loops; however, the difference between the control and the 1:3 loops was not significant The significance levels for this test were as follows:


1,000900800

* 600 | 5005 400at3 300

200100

00

1,000900800

» 600 f 500ID

300200100

0

10

Control loop

20 30 Week

40

1,000 900 800

tJ 700a 600| 500^ 4003 300

200100

50

1:10 loop

10 20 30 Week

40 50

1:3 loop

0 10 20 30 40 50 Week

Figure 4.7b Total lead levels, weeks 1 through 48, Baxter lead loops (reduced scale)

/12 Development of a Pipe Loop Protocol

25,000

20,000

15,000

* 10,000~o

& 5,000

J3 o-5,000

-10,000

25,000

20,000

15,000

* 10,000CA

J3 5,000

J3 0

-5,000

-10,000 ,20

25

Control loop

30 35 Week

40

20,000

15,000

* 10,000"w

J3 5,000•ao

-5,000

-10,000 -20

1:3 loop

45 50

1:10 loop

25 30 35 Week

40 45 50

25 30 35 Week

40 45 50

Figure 4.8 Total lead levels, weeks 25 through 48, Baxter lead loops

Lead loops compared

Control and 1:10 Control and 1:3


Wilcoxontest significance level (p level)

.059 percent 12.25 percent

A detailed explanation of the significance levels (p levels) can be found in standard statistical texts; however, in general a significance level of 12.25 percent indicates that there is a 12.25 percent chance of rejecting the hypothesis that the 1:3 treatmenthasno effectonleadlevels. Asignificance level of 5 percent or lowerwould generally be required for the treatment to be accepted as effective. For the 1:10 treatment, the significance level of .06 percent is well below the 5 percent level and therefore indicates that the treatment is effective. The relative difference inlead levels between the control and the two treated lead loops is shown in Figure 4.9, a box and whiskers plot that displays the mean, the standard error about the mean, and the standard deviation of the lead levels measured between weeks 25 through 48. Lead level data from the 1:3 treated loop have a much larger standard error and standard deviation than data from the 1:10 treated loop, and therefore there is less confidence that the 1:3 treatment effectively reduces lead levels compared to the control group.

Lead-Soldered Copper Loops. Total lead and total copper levels were measured on 37 samples from the lead-soldered copper loop that was fed control water, and 38 samples each were collected from the two treated lead-soldered copper loops (1:10 and 1:3 zinc orthophosphate treatment). These data were collected over a 48-week period from January 1 through December 5,1991. All samples were 1L in volume and were collected after a 24-hour standing time. Table 4.7 and Figures 4.10 and 4.11 display these data, which are summarized in the following:

Number of Treatment samplesControl1:101:3

373838

Lead levels (ug/L)Mean192 279 207

Median173 140 128

Minimum

21 43 14

Maximum679

1,214 1,060

Range658

1,171 1,046

Number of Treatment samplesControl1:101:3

373838

Copper levels, (ug/L)Mean246

55 163

Median250 50

168

Minimum110

0 50

Maximum465 310 240

Range355 210 190


9,000

6,000

s- 3,000

-3,000

-6,000

O Meani—i Standard Error

T Standard Deviation

Control 1:10 treatment 1:3 treatment

Figure 4.9 Box and whiskers plot of lead levels, weeks 25 through 48, Baxter lead loops

Significantly lower copper levels were measured from the 1:10 treated loop as compared to the control loop and the 1:3 treated loop; however, no such reduction in lead levels was measured. The lead levels measured from all three loops displayed a negative trend (i.e., lead levels were getting lower as the study progressed), as can be seen in Figure 4.10. These trends are significant (Spearman r values of-.94, -.79, and -.93) and indicate that lead levels had not yet stabilized. The copper levels did not display significant trends and therefore appearto have stabilized in all three loops (Figure 4.11).

Visual examination of the dataindicates that the lead levels in all three loops may have stabilized by week 25 of the study. To evaluate this hypothesis, trends were estimated forthe lead level data from weeks 25 through 48 (Figure4.12). The trends in lead levels measured during this time were still slightly negative in the control loop and the 1:3 treated loop, indicating that the lead levels had not yet stabilized. Lead levels appeared to be decreasing until week 35 in the control loop and the 1:3 treated loop. Using lead level data from weeks 35 through 48 would have provided only six data points for comparison; therefore, the data from weeks 25 through 48 were used to evaluate treatment differences. These data are summarized below.


Table 4.7 Water quality of standing samples from AWWARF lead-soldered copper loops, Philadelphia Water Department, Baxter WTP

Date

01/10/9101/17/9101/24/9101/31/9102/07/9102/14/9102/21/9102/28/9103/07/9103/14/9103/21/9103/28/9104/04/9104/11/9104/18/9104/25/9105/02/9105/09/9105/16/9105/23/9105/30/9106/06/9106/13/9106/20/9106/27/9107/1 1/9107/18/9107/25/9108/01/9108/08/9108/15/9108/22/9109/10/9110/17/9110/24/9111/07/9111/21/9112/05/91


Week

123456789

1011121314151617181920212223242527282930313233364142444648

events

deviations

Control

4036795234722302503211942273062252743141731781852212181821421706765—

10311311314010588

12653392122485650

37192144

3,342

Lead levels, (H9/L)

1:10 1:3 treatment treatment

1,1721,214

522560495492506312428530553387403321242151213150114768845436251

1801171071121091311059685

1311267099

38279275135

1,0601,028

49044429635034427433635026326426618717815221622115698

1034655205254715545706467521430341851

38207235

2,233

Copper levels, (P9/L)

1:10 1:3 Control treatment treatment

465456310286290230210290250200260170270160260250200110270170300170220

—180330220250260260190400230180260180160190

37246

765,968 2

3106734384040509030807020404020

000

20202020503040

1006050606060506090

100806070

385450

,517

17415415616521020019019019015019017022020020019019016024017023011015050

110180140120150150110110150180170120160100

3816339

2,264

— indicates no data collected


1,400

1,200

1,000

3 800

Control loop

400

1 200

0

-200

-4000 10 20 30

Week

1,400

1,200

1,000

* 600u|> 400

| 200

0-200

-4000

1,400

1,200

1,000

800

1:3 loop

60

J5 400

2 200

0-200

-400

40 50

1:10 loop

10 20 30 Week

40 50

0 10 20 30 40 50 Week

Figure 4.10 Total lead levels, weeks 1 through 48, Baxter lead-soldered copper loops


500450400

Control loop

250uI 200§•150 U

10050

0 0 10 20Week

30

500450400350

£ 250uI. 200§•150

10050° 0

40 50

1:10 loop

10 20 30 40 50 Week

500

450

400

J350M

1250uI200§•150

10050

0

1:3 loop

0 10 20 30Week

40 50

Figure 4.11 Total copper levels, weeks 1 through 48, Baxter lead-soldered copper loops


200180160

J 140 !£ 120•i 100I 80£ 60

4020°20

Control loop

25 30 35 Week

40 45 50

200180160

, 1401l204 100I 8° J3 60

4020

"20

1:10 loop

25 30 35 Week

40 45 50

zuu

180

160, 140S 120 •S 1001 8° % 60

40

20 °2

.

-— JL '••• •""»-" ——— —— ——— _____£____^ •

. •

0 25 30 35 40 45 5( Week

Figure 4.12 Total lead levels, weeks 25 through 48, Baxter lead-soldered copper loops

Number of


Weeks 25-48, lead levels, (ug/L)

Treatment samples Mean Median Minimum Maximum RangeControl 14 77 72 21 140 1191:10 14 109 108 51 180 1291:3 14 48 52 14 71 57

The mean and median lead levels and the overall range of lead values are much lower for data from weeks 25 through 48 compared to all of the data. Based on the mean lead levels from this period, there appears to be a 37 percent reduction in lead levels between the control loop and the 1:3 treated loop. Lead level data from the 1:10 treated loop were actually higher than those of the control loop, with a broader range of lead values measured.

The impact of treatment on lead and copper levels was evaluated using a nonparametric Wilcoxon matched pairs test. Significance levels for the lead level data for the test during weeks 25 through 48 were as follows: When the control loop and the 1: lOtreated loop were compared, the significance level was .85 percent; when the control loop and the 1:3 treated loop were compared, the significance level was .72 percent.

A significance level of 5 percent or lower would be required to accept that there was a significant difference in lead levels. The significance levels are well below 5 percent; however, the lead levels from the 1:10 treated loop were significantly higher than those of the control loop. The lead levels from the 1:3 loop were significantly lower than those of the control loop. This relationship is easily seen in a box and whiskers plot that displays the mean, standard error around the mean, and the standard deviation of data. A box and whiskers plot for the lead levels data from the lead-soldered copper loops is shown in Figure 4.13.

The copper levels from the control loop and the treated loops also displayed a significant difference on the basis of all data from weeks 1 through 48. In both treatments applied, the copper levels were significantly lowerthanthe copper levels observed from the control loop, as can be seen in the box and whiskers plot in Figure 4.14.

In summary, the statistical evaluation of the lead-soldered copper A WWARF loops at the Baxter treatment plant indicates a mix of conclusions with regard to treatment effectiveness. The 1:3 zinc orthophosphate chemical appears to have provided the best reduction in lead levels, as well as narrowing the range of lead levels measured, which could indicate amore consistently effective treatment. The 1:10 zinc orthophosphate chemical provided the best overall reduction in copper levels, however, and this reduction is more statistically significant than the lead level reduction with the 1:3 zinc orthophosphate chemical.

Operational ConsistencyThe Philadelphia corrosion study pipe racks were operated for a total of 48

weeks. The pipe racks were checked four times weekly, twice by filter plant personnel and twice by water quality staff. These individuals manually turned off the flow and returned the nextday to collect standing samples. Field water quality parameters were checked once per week, and the results were used to adjust the feed pumps to maintain


150

120

JS ID

I

90

60

30O Mean

C^l Standard ErrorT Standard Deviation

Control 1:10 treatment 1:3 treatmentFigure 4.13 Box and whiskers plot of lead levels, weeks 25 through 48, Baxter lead-soldered copper loops

400

320

240

I § 16°

80

MeanStandard Error Standard Deviation

Control 1:10 treatment 1:3 treatmentFigure 4.14 Box and whiskers plot of copper levels, weeks 1 through 48, Baxter lead-soldered copper loops


constant water quality conditions. The flow rate for feeding the orthophosphate chemicals was set at 8 mL/min during the startup period for the racks. Flow rates lower than 8 mL/min were too slow for the displacement pump that fed the chemical to the rack, and higher flow rates created a pulse effect, with air bubbles entering the loops.

During pipe rack startup, a tendency for the chemical solution to settle was discovered, so a regular chemical mixing schedule was implemented. Another problem related to chemical feed consistency was the freezing point of the chemicals used, which was 45°F (7.2°C) forthe 1:3 zinc orthophosphate and 29°F (-1.6°C) for the 1:10 zinc orthophosphate. The water temperatures in the Philadelphia system can drop to between 36 and 41 °F (2 and 5°C) during the coldest months, February through April, and actual crystal formation was observed in the bulk solution for the 1:3 chemical.

The only other problem during operation of the Baxter WTP pipe racks was bacteriological contamination of the 1:3 zinc orthophosphate loop shortly after startup. High heterotrophic plate count (HPQ values (>5,700 cfu/mL) were measured in standing samples from the 1:3 zinc orthophosphate lead loop. Removal and chlorination of the sample tap eliminated the problem.

New York City Bureau of Water Supply and Wastewater CollectionWater Quality Data Summary and Statistical Evaluation

The major purpose of the New York City corrosion control study was to evaluate the impact of several different treatments on reduction of lead and copper levels. Two pipe racks were installed on the Croton system and eight were installed on the Catskill Delaware system. The following treatment alternatives were studied:

Pipe racknumber Supply Treatment1 Croton Zinc orthophosphate (pH 7.0)2 Croton Control (no treatment)3 Catskill Delaware Control (no treatment)4 Catskill Delaware Caustic soda (pH 7.5)5 Catskill Delaware Zinc orthophosphate (pH 6.5, then 7.0)6 Catskill Delaware Zinc orthophosphate and caustic soda (pH 7.5)7 Catskill Delaware Blended orthophosphate and caustic soda (pH 7.5)8 Catskill Delaware Blended orthophosphate (pH 6.5, then 7.0)

The study was initiated at a pH of 6.5. After2 months, pH was elevated to 7.0using NaOH.

A copper loop, a lead-soldered copper loop, and a lead loop were incorporated into each of the 10 pipe racks. Metals levels were measured from 1-L, 16-hour standing samples. Samples were collected once every two weeks for approximately 38 weeks. The analytical data are discussed below for each water supply.


Croton Pipe Racks, Copper Loops. Copper levels were measured on 23 samples from both the control loop (Loop 2) and the treated loop (Loop 1) over a period of 38 weeks from June 7,1991, through February 26,1992. These data are displayed in Table 4.8 and Figure 4.15 and are summarized below.

Weeks 1-38, copper levels from

Croton copper loops (mg/L)Loop Number of ———————————————————— number Treatment samples Mean Median Minimum Maximum1 Zinc ortho-

phosphate 23 1.195 1.21 0.624 1.872 Control 23 0.963 1.03 0.237 1.84

Copper levels from both loops behaved similarly throughout the study period, with what appeared to be cyclical changes in concentrations. A strong negative trend in the data was observed for the first several weeks of operation until approximately the middle of August 1991. After this point, levels began to rise and may have reached a plateau by the end of October 1991. This fluctuation in copper levels may have been seasonally induced or may have been caused by a treatment change in the influent water.

Visual examination of these data indicates that the zinc orthophosphate treatmentmay have resulted in copper levels slightly lower than those of the control water. A nonparametric Wilcoxon matched pairs test was performed on these data that indicated a statistically significant difference. The relative difference in copper levels between these two populations of data can be seen in the box and whiskers plot displayed in Figure 4.16. Although the mean copper levels are obviously different, there is a similar range of copper levels measured throughout the study period. The ratio of the standard deviation to the mean (coefficient of variation [CV]) for the data from both loops is 1:3, indicating similar variability in the data.

Croton Pipe Racks, Lead-Soldered Copper Loops. Twenty-three copper and 24 lead samples were measured from the control loop (Loop 2) and the treated loop (Loop 1) over a period of 38 weeks from June 7,1991, through February 26, 1992. These data are displayed in Table 4.9 and Figure 4.17 and are summarized in the following:

Weeks 1-38, lead levels from Croton

lead-soldered copper loops (mg/L)Number of

number Treatment samples Mean Median Minimum Maximum12

Zinc ortho-phosphate

Control2323

0.0410.181

0.0170.173

0.0050.062

0.250.402


Table 4.8 Water quality of standing samples from AWWARF copper loops, New York City, Croton supply

Date

06/07/9106/14/9107/16/9107/25/9107/31/9108/07/9108/14/9108/21/9109/05/9109/18/9110/02/9110/08/9110/16/9110/24/9110/30/9111/13/9112/05/9112/11/9112/18/9101/03/9201/10/9202/20/9202/26/92

Sampling eventsMeanStandard deviation

Day

07

39485461687590

103117123131139145159181187194210217258264

Copper levels, (mg/L)

Loop 1 (zinc orthophosphate)

1.3401.0981.0520.2370.6800.6210.6380.4740.7910.6940.8641.1101.0301.1101.0701.121.221.201.0500.9701.0200.9251.840

230.9630.319

Loop 2 (control)

1.8721.4211.2310.9020.8360.6950.8310.6240.7190.7940.9931.1201.5401.4001.0401.471.531.61.2801.2101.4401.1401.790

231.1950.351

I<u <u

ou

21.91.81.71.61.51.41.31.21.1

10.90.80.70.60.50.40.30.2

05/22/91 07/01/91 08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92

Date• Loop 1, zinc orthophosphate + Loop 2, control

Figure 4.15 Total copper levels, Croton copper loops

2.4

2.2

1.8I"«f 1.4<u

<D g, OH O

0.8

0.6

0.4

0.2

0

»11

| Mean

1=1 2 Standard Error


Loop 1 Loop 2 Zinc orthophosphate Control

Figure 4.16 Box and whiskers plot for copper levels, Croton copper loops


Table 4.9 Water quality of standing samples from AWWARF lead-soldered copper loops, New York City, Croton supply

Date

06/07/9106/14/9107/02/9107/16/9107/25/9107/31/9108/07/9108/14/9108/21/9109/05/9109/18/9110/02/9110/08/9110/16/9110/24/9110/30/9111/13/9112/05/9112/11/9112/18/9101/03/9201/10/9202/20/9202/26/92


Day

07

2539485461687590

103117123131139145159181187194210217258264

Lead levels


0.2500.1500.1100.0270.0490.0370.0560.0270.0470.0710.0170.0250.0130.0100.0100.0080.0050.0050.0050.0050.0060.0050.009

230.0410.057

(mg/L)

Loop 2 (control)

0.2500.2300.2100.1560.1730.1990.2450.1330.4020.0700.1000.0790.1200.1730.1300.0620.1180.1950.1920.1720.1320.2240.390

230.1810.085

Copper levels


0.9170.7180.5280.7250.4730.6170.6220.6630.7371.1401.6700.8971.1601.3101.2601.2001.311.331.361.1401.0901.0000.9681.840

241.0280.347

(mg/L)

Loop 2 (control)

1.9541.0050.6130.9260.5211.1600.4570.4090.6480.5210.6570.6891.1501.2601.4301.3201.411.831.841.4401.4701.6001.3401.830

241.1450.481

Loop numoer

Weeks 1-38,copper levels from Croton

lead-soldered copper loops (mg/L)Number oi

samples

24 24

Mean

1.03 1.15

Median

1.05 1.21

Minimum

0.473 0.409

Maximum

1.84 1.95

TreatmentZinc ortho-

phosphate Control

The control loop exhibited somewhat erratic lead levels that did not appear to stabilize over the 38-week period. Lead levels from the treated lead loop (Loop 1) were much lower and appeared to stabilize after late October 1991. Figure 4.18a displays the estimated trend line for lead levels from the treated loop. This trend was highly significant (Spearman r=-.91, p level=0). To evaluate whether the lead levels had stabilized after October 30,1991, a trend line was estimated using only data collected after that date. Figure 4.18b displays this trend line, which was not


0.45

0.4

0.35

0.3

S, 0.25C/3

13>•« 0.2•a

0.15

0.1

0.05

05/22/91 07/01/91 08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92Date

Loop 1, zinc orthophosphate Loop 2, control

I

ao U

2.12

1.91.81.71.61.51.41.31.21.1

10.90.80.70.60.50.4

05/22/91 07/01/91 08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92Date

• Loop 1, zinc orthophosphate + Loop 2, control

Figure 4.17 Total lead and copper levels, Croton lead-soldered copper loops


0.3

0.25

0.2

0.15

o-i0.05

0

-0.05 -0.1

-0.1550 100 150

Day200 250 300

Figure 4.18a Estimated trend line for lead levels, Croton lead-soldered copper Loop 1, all data

0.01

0.009

0.008

f 0.007CA

| 0.006

jj 0.005

0.004

0.003

0.002140 160 180 240 260200 220

Day

Figure 4.18b Estimated trend line for lead levels, Croton lead-soldered copper Loop 1, days 145 through 264

280


significant (Spearman r=.22, p level = .6); i.e., lead levels appear to have stabilized after 145 days.

Visual examination of the data indicates that the zinc orthophosphate treatment resulted hi significantly lower lead levels from the lead-soldered copper loops. Results from the Wilcoxon matched pairs test using data from days 145 through 264 were significant (p level = .01), which supports this indication. The relative difference in lead levels between these two populations of data can be seen in the box and whiskers plot displayed in Figure 4.19. The ratios of the standard deviation to the mean for the lead level data from both loops are as follows:

Croton lead-soldered copper loops, ratio of standard deviation

to mean for lead levelsLoop number Treatment Days 1-264 Days 14-264

12

Zinc orthophosphate Control

1:0.7 1:2.0

1:4.0 1:2.0

These ratios indicate that the variability in lead levels from the treated loop (Loop 1) was dramatically reduced after the levels stabilized. Lead levels from the control loop (Loop 2) remained essentially the same throughout the study period.

u.o 0.45

0.4 0.35

0.3 0.25

0.2 0.15

0.1 0.05

0 -0.05

-0.1

-

i i

-

|Mean




Figure 4.19 Box and whiskers plot of lead levels, Croton lead-soldered copper loops, days 145 through 264

u

3

2.5

1.5

& 0.5U

0

-0.5

| Mean

<=> 2 Standard Error


Loop 1 Zinc orthophosphate

Loop 2 Control

Figure 4.20 Box and whiskers plot of copper levels, Croton lead-soldered copper loops, all data

Copper levels from both loops behaved similarly throughout the study period. As with the copper-only loops, copper levels appeared to change in acyclical pattern, with a strong negative trend observed during the first several weeks of operation followed by an increase and a possible plateau. Without several years' worth of data it may not be possible to determine whether the fluctuations seen are caused by seasonal water quality changes.

Visual examination of these data indicates that the zinc orthophosphate treatment did notresult in consistently lower copper levels. Copper levels from the treated loop were initially higherthan those from the control; then they dropped below control levels; then they were higher again for the last several weeks of the study. A nonparametric Wilcoxonmatched pairs test was performed using all of the data. The test was significant (p level =. 1). The box and whiskers plot in Figure 4.20 displays the relative difference in copper levels between these two populations of data. As indicated by the Wilcoxon test statistic, the difference between the treated and the control groups is not readily apparent The ratio of the standard deviation to the mean for copper levels was l:3forthe control loop and 1:2 for the treated loop, indicating that copper levels from the treated loop were more variable than those from the control.

Croton Pipe Racks, Lead Loops. Lead levels were measured on 23 samples from the control loop and on 24 samples from the treated loop over a period of 38 weeks from June 8,1991,throughFebruary26,1992. These data are displayed in Table 4.10 and Figure 4.21 and are summarized as follows:


Table 4.10 Water quality of standing samples from AWWARF lead loops, New York City, Croton supply_____________________________________

Lead levels (mg/L)

Date

06/08/9106/14/9107/02/9107/16/9107/25/9107/31/9108/07/9108/14/9108/21/9109/05/9109/18/9110/02/9110/08/9110/16/9110/24/9110/30/9111/13/9112/05/9112/11/9112/18/9101/03/9201/10/9202/20/9202/26/92


Day

06

2438475360677489

102116122130138144158180186193209216257263


0.1800.1900.1400.2200.1900.0450.0750.1440.1210.1350.3940.3610.0180.0930.1180.0790.1310.2040.1390.1910.2020.1380.1660.233

240.1630.084

Loop 2 (control)

0.4601.200

0.9601.1203.0501.4501.5201.9701.4201.2401.5601.5000.6300.6701.61.151.341.041.3700.6020.8120.8860.406

231.2150.557

Loop number1

2

TreatmentZinc ortho-

phosphate Control

Number of samples

24 23

Lead levels from Croton lead loops (mg/L)

Mean

0.163 1.22

Median

0.142 1.20

Minimum

0.018 0.406

Maximum

0.394 3.05

Lead levels from the control loop appeared to be steadily decreasing overthe 38-week period and had not reached stability by the end of the study period. Lead levels from the treated lead loop were considerably lower and remained relatively stable over the entire study period. Visual examination of the data indicates that the zinc orthophosphate treatment resulted in significantly lower lead levels from the lead loops. Results from the Wilcoxon matched pairs test using data from the entire study


3.43.2

32.8 2.6 2.4 2.2

dfl 2

rf 1-8 1 1.6 "S 1-4 % 1.2

10.8 0.6 0.4 0.2

005/22/91 07/01/91 08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92

Date

• Loop 1, zinc orthophosphate + Loop 2, control

Figure 4.21 Total lead levels, Croton lead loops

3

2.5

1.5

a)

J 0.5

-0.5

-I

| Mean

CD 2 Standard Error



Figure 4.22 Box and whiskers plot of lead levels, Croton lead loops, all data


Table 4.11 Water quality of standing samples from AWWARF lead loops, New York City, Catskill Delaware supply

Lead levels (mg/L)

Date

08/22/9108/27/9109/10/9109/17/9109/24/9110/01/9110/08/9110/16/9110/24/9111/13/9112/05/9112/11/9112/18/9101/03/9202/20/9202/26/9204/08/9204/15/9204/29/9205/05/9205/13/9205/20/9205/27/9206/03/9206/09/9206/17/9206/23/9207/09/92

Sampling MeanStandard

Day

251926334047556383105111118134182188230237251257265272279286292300306322

events

deviation

Loop 3 (control)

1.400

2.810—

2.1001.5500.5801.5101.3004.562.063.271.9303.3101.7402.2902.1502.3603.3601.0603.1102.0901.2201.1201.5200.5811.4700.818

26 1.9720.949

Loop 4 (PH 7.5)

B1JL

0.349—

0.275—

0.2820.1400.1600.1500.6650.2050.4080.4080.3924.0202.2400.7880.2790.2860.2450.2460.2980.3401.1700.4310.2190.3540.452

25 0.5920.819

LoopS (zinc orthophosphate)

_1.838

—0.985

—1.2901.3600.6500.3261.32

0.0290.5050.5050.1360.3280.8130.1400.2850.1700.1530.2290.0390.1330.3110.2560.1190.0750.066

25 0.4500.422

Loop 6 (zinc orthophosphate,

pH 7.5)^_

0.619—

0.279—

0.1460.0970.1500.2490.9580.0290.1920.0980.0970.4010.7800.1590.1700.0190.0190.1140.0710.1100.0830.0710.0230.0360.025

25 0.2000.238

Loop? (blended

orthophosphate,

pH 7.5)

3.460—0.198—0.3600.1220.2230.1400.1640.2890.0630.0750.5460.2490.2801.7400.3540.6960.1960.5160.7860.5140.4370.0180.3510.3950.0840.510

26 0.4910.682

LoopS (blended

orthophosphate)

0.786—

0.670—

0.8400.3000.9810.4810.2290.4370.0550.1160.2800.0810.6841.2600.0940.1430.1920.0460.1040.0330.0810.0230.0720.0850.0240.044

26 0.3130.340


period support this assumption. The p level from the Wilcoxon test was highly significant at .000027. The box and whiskers plot displayed in Figure 4.22 demonstrates this difference in lead levels. The ratio of the standard deviation to the mean for lead levels from both loops was 1:2, indicating similar variability in the data.

Catskill Delaware Pipe Racks, Lead Loops. Lead levels were measured over a period of 46 weeks from August 22,1991, through July 9,1992. These data are displayed in Table 4.11 and Figures 4.23 through 4.25 and are summarized as follows:


Lead Loop 3

4.5

4

3.5

1 3

"3,2

2

1.5

1

0.5

4.5

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Lead Loop 4

4 -

3.5

3oo. 2.5

1.5

1

0.5

008/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92

DateFigure 4.23 Total lead levels, Catskill Delaware lead Loops 3 and 4


1.5 1.4 1.3 1.2 1.1

1J &b 0.9£ 0.8"uI 0.7

1 0.6

0.50.40.30.20.1

0

Lead Loop 5

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Lead Loop 6

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Figure 4.24 Total lead levels, Catskill Delaware lead Loops 5 and 6


Lead Loop 7

3.5

3

_u

3 1.5

0.5

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92

IM

T3

1.4

1.3

1.2

1.1

1

0.9

0.8

0.7

0.6

0.50.4

0.3

0.2

0.1

0

Lead Loop 8

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Figure 4.25 Total lead levels, Catskill Delaware lead Loops 7 and 8

Loop Number onumber Treatment samples

345

6

7

8

ControlpH7.5Zinc ortho-

phosphateZincorthophos-

phate, pH 7.5Blended ortho-

phosphate,pH7.5

Blended ortho-phosphate

2625

25

25

26

26

Weeks 1^6, lead levels from Catskill Delaware

lead loops (mg/L),f ———— ———————Mean

1.9700.592

0.450

0.200

0.491

0.313

Median

1.840.342

0.285

0.110

0.320

0.130

Minimum

0.5800.140

0.029

0.019

0.018

0.023

Maximum

4.564.02

1.36

0.96

3.46

1.26

The control loop exhibited very high lead levels that were somewhat erratic. Lead levels initially appeared to be decreasing; however, after approximately 1 month of operation, the levels increased dramatically. Forthe remainder of the study period, a slightly decreasing trend was observed. An estimated trend line for lead data from days 230 through 322 indicated a significant decreasing trend at the .02 percent level (p level = .015), as seen in Figure 4.26a. Lead level data from days 279 through 322 did not display a significant trend, indicating that the levels may have stabilized (Figure 4.26b). Without more data, however, it is difficult to tell whether this stabilization was seasonal in nature.

Lead Loop 4, which was treated with NaOH to apH of 7.5, displayed no trend in the data over the study period. Lead levels fell within a relatively stable range of 0.1 to 0.8 mg/L, with the exception of two samples collected during February 1992 whose levels were much higher (4.0 and 2.0 mg/L). Lead levels from Loop 5 (zinc orthophosphate) displayed a strongly negative trend throughout the study period (Spearman r = -.73), and this trend was highly significant (p level < .001). These levels appeared to stabilize approximately 230 days into the study. Evaluating the trend line for the data from days 230 through 322 indicated that although the estimated trend was still negative, it was not significant at the .1 p level. Estimated trend lines for lead Loop 5 are displayed in Figures 4.27a and 4.27b.

Lead Loop 6 was also treated with zinc orthophosphate; however, caustic soda was added as well to elevate the pH to 7.5. Lead levels from this loop also displayed a significant negative trend over the study period (p level = .001), as seen in Figure 4.28a. As with lead Loop 5, these levels appeared to stabilize after day 230 of the study period. The estimated trend line for days 230 through 322 suggests that stabilization may have taken place (see Figure 4.28b). The estimated trend line was still slightly negative but much flatter (Spearman r = -.37), and this line was not statistically significant (p level < .2).

Lead Loop 7, treated with ablended orthophosphate and caustic soda to apH of 7.5, displayed no discernible trend in the data throughout the study period. Lead Loop 8, treated with ablended orthophosphate alone, displayed a strongly negative trend (Spearman r = -.77), which was significant at the .0001 p level. This trend was


4

3.5

3

| 2- 5

*" O

1

0.5

0

-0.5 220 240 260 280 Day

300 320 340

Figure 4.26a Estimated trend line for lead levels, Catskill Delaware lead control Loop 3, days 230 through 322

2

1.8

1.6

1.2

1 10.8

0.6

0.4

0.2

'270 280 290 300 Day

310 320 330

Figure 4.26b Estimated trend line for lead levels, Catskill Delaware lead control Loop 3, days 279 through 322

1.6

1.4

1.2

'6 0.8

1 0.6

1 0.4

0.2

0

-0.2

-0.4

Discussion and Analysis of 'Results 139

50 100 150 200 Day

250 300 350

Figure 4.27a Estimated trend line for lead levels, Catskill Delaware lead Loop 5, all data

0.35

0.3

0.25

f 0.2e/T

1 0-15

1 0.1

0.05

0

-0.0: 240 260 280 Day

300 320 340

Figure 4.27b Estimated trend line for lead levels, Catskill Delaware lead Loop 5, days 230 through 322


Ien"

T3 IT3

1.1 1

0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

0-0.1-0.2

0 50 100 250 300150 200 Day


350

0.20.180.160.140.12

6 0.1•g 0.08& 0.06! 0.04

0.020

-0.02-0.04-0.06220 240 260 280

Day300 320 340

Figure 4.28b Estimated trend line for lead levels, Catskill Delaware lead Loop 6, days 230 through 322

still significantly negative after day 230 of the study; however, the estimated trend line fordata from days 279 through 322 indicated that the levels had stabilized (Spearman r=-. 14). Figures 4.29a and 4.29b display the estimated trend lines for all of the data as well as for data from days 279 through 322. All treated loops exhibited elevated lead levels during February 1992, indicating the possibility that incoming water quality may have been altered during this period.

A Wilcoxonmatched pairs evaluationofthe difference inleadlevels between the control loop (Loop 3) and the treated loops (Loops 4 through 8) indicated that all the treated loops produced lead levels that were significantly lower than those of the control (p level < .001), using data from the entire study period. These differences were still significant when data from days 230 through 322 were evaluated (p level < .05). These differences can be seen in the box and whiskers plots shown in Figures 4.30a and 4.30b. Figure 4.30a displays the mean and standard deviations for lead levels using data from the entire study period. Figure 4.30b displays the same information for lead levels measured between days 230 and 322 of the study period. The differences in lead levels between the control loop and the treated loops are still evident during days 230 through 322; however, the variability in lead levels measured from several of the loops appears to be reduced because the levels have stabilized. The ratios of the standard deviation to the mean for lead levels from all five lead loops support this assumption.

Catskill Delaware lead loops, ratio of standard deviation to mean for lead levels

Loop number345678

The treatment tested in lead Loops 5,6, and 8 appears to provide the best reductions in lead levels compared to those of the control loop, as well as the lowest variability in lead levels.

Catskill Delaware Pipe Racks, Copper Loops. Copper levels were measured over a period of 46 weeks from August 22,1991, through July 9,1992. These data are displayed in Table 4.12 and Figures 4.31 through 4.33 and are summarized in the following list:

Days 1-3221:2.01:0.71:1.01:0.81:0.71:1.0

Days 230-3221:2.01:1.51:2.01:1.41:2.01:1.5

1.6

1.4

1.2

1

e. 0.8<A

1 °'6

"S 0.4^0,

0-0.2

-0.450 100 150 200

Day250 300 350


0.12 0.11 0.1

0.09 0.08

a 0.07 I 0.06 1 0.05

0.04 0.03 0.02 0.01

0-0.01-0.02

270 280 290 300 Day

310 320 330

Figure 4.29b Estimated trend line for lead levels, Catskiil Delaware lead Loop 8, days 279 through 322

a 2i

CD -1-2

-3


QD <=> 2 Standard Error


Loop 3 Loop 4 Loop 5 Loop 6 Loop 7 Loop 8Figure 4.30a Box and whiskers plot of lead levels, Catskill Delaware lead loops, all data

03

4.5

4

3.5

2.5

2

1.5

0.5

0

-0.5 -1



Loop 3 Loop 4 Loop 5 Loop 6 Loop 7 Loop 8Figure 4.30b Box and whiskers plot of lead levels, Catskill Delaware lead loops, days 230 through 322


Table 4.12 Water quality of standing samples from AWWARF copper loops, New York City, Catskill Delaware supply

Copper levels (mg/L)

Date

08/22/9108/27/9109/10/9109/17/9109/24/9110/01/9110/08/9110/16/9110/24/9111/13/9112/05/9112/11/9112/18/9101/03/9202/20/9202/26/9204/08/9204/15/9204/29/9205/05/9205/13/9205/20/9205/27/9206/03/9206/09/9206/17/9206/23/9207/09/92

SamplingMeanStandard

Day

05

1926334047556383

105111118134182188230237251257265272279286292300——

events

deviation

Loop 3(zinc ortho-phosphate)

1.940—

2.040—

2.1103.6002.8603.0702.3603.022.311.881.5401.3802.3302.0701.7001.7601.3701.4501.2801.3501.3401.7201.7001.7201.0001.640

261.9440.619

Loop 4(pH 7.5)

—— .

0.712—

0.652—

0.8920.5840.5020.5631.15

0.7420.8560.5260.7682.2900.7740.0400.1670.1500.1130.1140.4690.3350.2480.2150.6630.4821.020

250.6010.454

Loop 5(zinc ortho-phosphate)

_2.870

—2.800

—3.5802.8803.2801.0201.45

0.4020.0460.6660.7461.1801.2900.4230.0530.5850.7040.9300.7850.7980.0161.1200.4990.6140.559

251.1721.026

Loop 6(zinc ortho-phosphate,

pH 7.5)

__

0.235—

0.390—

0.1620.1000.2520.1771.51

0.2230.2720.1940.1730.4580.6340.3880.1670.1300.1960.1220.2610.3150.0980.1880.075

0.1100.134

250.2790.281

Loop 7(blendedortho-

phosphate,pH 7.5)

0.993—0.293

—0.3410.0800.1260.3020.2990.2730.0250.1340.2060.0294.1100.7800.2200.2110.1900.1480.0980.1050.1100.1280.0250.4990.1100.114

260.3830.777

Loop 8(blendedortho-

phosphate)

2.430—

1.390—2.1403.2302.2602.6600.7021.630.9320.131.4501.0602.4401.8400.7460.1230.2280.5131.0400.8661.0300.3081.1201.2800.3700.718

261.2550.834


Copper Loop 3

I

00

<u o(UIu

2.6

2.4

2.2

2

1.8

1.6

1.4

1.2

1

0.8

0.6

0.4

0.2

0

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Copper Loop 4

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Figure 4.31 Total copper levels, Catskill Delaware copper Loops 3 and 4


Copper Loop 5

3.5

3

S,a 1 - 5

0.5

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Copper Loop 6

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92 Date

Figure 4.32 Total copper levels, Catskill Delaware copper Loops 5 and 6


4.5Copper Loop 7

3.5

I

uJO

Isex a o U

2.5

1.5

0.5

o&o U

3.43.2

32.82.62.42.2

21.81.61.41.2

10.80.60.40.2

0

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Copper Loop 8

Figure

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

4.33 Total copper levels, Catskill Delaware copper Loops 7 and 8

Loopnumber Treatment

3 Control4 pH 7.55 Zinc ortho-

phosphate6 Zincorthophos-

phate, pH 7.57 Blended ortho-

phosphate, pH7.5

8 Blended orthophosphate

Number of samples

2625

25

25

Copper levels fromCatskill Delaware

copper loops (mg/L)

Mean Median Minimum Maximum

26

26

1.970 1.84 0.580 4.560.592 0.342 0.140 4.02

0.450 0.285 0.029 1.36

0.200 0.110 0.019 0.96

0.491 0.320 0.018 3.46

0.313 0.130 0.023 1.26

The control loop exhibited a very strong negative trend in copper levels for the entire study period (Spearman r = -.72, p level = .000034), as seen in Figure 4.34a. Copper levels decreased for the first 5 months of the study, then increased slightly for a short period before decreasing once again. Levels appeared to stabilize after 230 days. The estimated trend line for copper data from days 230 through 322 was only slightly negative, with a Spearman r of -. 14 (Figure 4.34b). Copper levels from Loop 4 did not exhibit any trend with time. As with Loop 3, there was a brief period of elevated copper levels approximately 5 months into the study; however, these levels decreased quickly, followed by a steady increase during the last 2 months of the study period. As with the lead loops, these changes may have been due to inconsistent influent water quality.

Copper Loop 5 displayed a very strong negative trend in copper levels, with levels also stabilizing after day 230 of the pipe rack operation. Figures 4.35 a and 4.35b display the estimated trend lines for these data. Loops 6 and 7 did not exhibit strong decreases in copper levels with time; however, copper levels from both loops appeared to stabilize after day 230. Both loops also had high copper levels measured approximately 5 months into the study period. Copper levels from Loop 8 displayed a decreasing trend, similar to Loop 5, and also exhibited high levels for a brief period after 5 months of operation.

A Wilcoxon matched pairs evaluation of the difference in copper levels between the control loop (Loop 3) and the treated loops (Loops 4 through 8) indicated that all the treated loops produced copper levels that were significantly lower than those of the control (p level < .005), using data from the entire study period as well as data from days 230 through 322. These differences can be seen in the box and whiskers plots in Figures 4.36a and 4.36b. The range of copper levels measured is much smaller when data from days 230 through 322 are used. When comparing the

4

3.5

X 2.5u

a, o U1.5 •

1 •

0.5 0 50 100 250 300 350150 200 Day

Figure 4.34a Estimated trend line for copper levels, Catskill Delaware copper Loop 3, all data

1.9 •

1.8

60 ,E 1.6<yj"

13 1.5jub 1.4a,I'-3

1.2

1.1

1

0.9220 240 260 280 Day

300 320 340

Figure 4.34b Estimated trend line for copper levels, Catskill Delaware copper Loop 3, days 230 through 322


I

4

3.5

3

2.5

2to

I 1.5

I 1U

0.5

0

-0.5

-10 50 100 150 200

Day250 300 350

Figure 4.35a Estimated trend line for copper levels, Catskill Delaware copper Loop 5, all data

1.3 1.2 1.1

1 0.9^e o.s

J3 0.6 0.5

S0.3 0.2 0.1

0 -O.U220 240 260 280

Day300 320 340

Figure 4.35b Estimated trend line for copper levels, Catskill Delaware copper Loop 5, days 230 through 322

H-.O

43.5

32.5

oo 2JS L5 13 1 > lS 0.51 oU -0.5

-1 -1.5

-2 .9 <;

.--

[ r-

-.-

i

Lii

Ui J

Q

'-

D [E

i

;ii 1-•

-

en 2 Standard Error


Loop 3 Loop 4 Loop 5 Loop 6 Loop 7 Loop 8

Figure 4.36a Box and whiskers plot of copper levels, Catskill Delaware copper loops, all data

2.5

1.5d00

<a

S 0.5o- §•

<-> 0

-0.5

-1

c=i 2 Standard Error



Figure 4.36b Box and whiskers plot of copper levels, Catskill Delaware copper loops, days 230 through 322

Tabl

e 4.

13

Wat

er q

ualit

y of

sta

ndin

g sa

mpl

es fr

om A

WW

ARF

lead

-sol

dere

d co

pper

loop

s, N

ew Y

ork

City

, Cat

skill

Dela

ware

sup

ply

Lead

leve

ls (m

g/L)

Dat

e

08/2

2/91

08

/27/

91

09/1

0/91

09

/17/

9109

/24/

9110

/01/

9110

/08/

9110

/16/

9110

/24/

9111

/13/

9112

/05/

9112

/11/

9112

/18/

9101

/03/

9202

/20/

9202

/26/

9204

/08/

9204

/15/

9204

/29/

9205

/05/

9205

/13/

9205

/20/

9205

/27/

9206

/03/

9206

/09/

9206

/17/

9206

/23/

9207

/09/

92

Sam

plin

gM

ean

Stan

dard

Day 0 5 19

26 33 40 47 55 63 83 105

111

118

134

182

188

230

237

251

257

265

272

279

286

292

300

306

322

even

ts

devia

tion

Loop

3

(con

trol)

0.02

7

0.02

7

0.01

50.

019

0.01

10.

008

0.02

40.

061

0.01

50.

027

0.03

60.

035

0.01

80.

020

0.09

00.

024

0.04

00.

063

0.09

30.

013

0.04

80.

041

0.03

00.

010

0.01

30.

008

26 0.03

10.

023

Loop

4

(pH

7.5)

0.02

7

0.04

2—

0.03

20.

051

0.05

50.

118

0.06

2—

0.22

90.

142

0.09

00.

027

0.02

30.

035

0.02

30.

057

0.05

60.

043

0.04

30.

073

0.03

30.

038

0.03

00.

017

0.05

4

24 0.05

80.

046

Loop

6

Loop

7

Loop

S

(zin

c (b

lend

ed

(zin

c or

tho-

or

tho-

or

tho-

ph

osph

ate,

pho

spha

te,

phos

phat

e)

pH7.

5)

pH7.

5)

0.07

2

0.02

7—

0.01

00.

010

0.04

10.

009

0.02

20.

006

0.02

0.00

50.

013

0.00

80.

020

0.00

50.

006

0.00

50.

021

0.09

40.

039

0.01

00.

098

0.04

60.

011

0.00

50.

005

25 0.02

40.

026

0.02

7

0.02

7—

0.01

60.

700

0.01

10.

015

0.21

60.

007

0.02

10.

076

0.03

30.

037

0.63

20.

014

0.00

50.

027

0.00

50.

005

0.01

10.

023

0.01

50.

005

0.00

80.

005

0.00

6

25 0.07

80.

179

0.16

1

0.13

2

0.20

00.

071

0.04

50.

055

0.19

00.

094

0.08

60.

085

0.10

80.

085

0.04

00.

007

0.00

70.

007

0.01

60.

006

0.00

50.

005

0.03

40.

420

0.01

00.

012

0.00

50.

017

26 0.07

30.

090

Loop

S

(ble

nded

or

tho-

ph

osph

ate)

0.02

7

0.02

7

0.01

30.

006

0.00

50.

005

0.01

40.

007

0.00

50.

014

0.01

70.

820

0.01

90.

007

0.00

50.

008

1.46

00.

088

0.00

50.

005

0.02

30.

638

0.08

40.

053

0.07

10.

040

26 0.13

30.

327

Loop

S

(con

trol)

1.10

0

1.13

0

1.33

02.

780

2.05

02.

700

1.61

01.

912.

632.

131.

930

1.94

02.

720

2.40

01.

580

2.26

01.

660

2.73

01.

720

1,86

01.

800

2.07

02.

090

1.84

02.

550

1.82

0

26 2.01

30.

471

Loop

4

(pH

7.5)

0.63

4

0.62

4—

0.79

20.

628

0.64

50.

695

0.94

6—

0.51

10.

432

0.44

32.

740

0.84

00.

254

0.11

20.

110

0.09

10.

070

0.35

30.

360

0.25

90.

202

0.38

20.

443

2.08

0

24 0.61

00.

601

Copp

er le

vels

(mg/

L)

Loop

S (z

inc

orth

o-

phos

phat

e)

1.53

0

2.00

0—

2.37

01.

840

2.31

00.

707

1.33

0.29

20.

546

0.62

80.

494

1.47

01.

500

0.53

60.

076

0.46

00.

666

0.97

2° 0

.896

0.82

90.

311

1.05

00.

877

0.77

30.

744

251.

008

0.61

5

Loop

S

(zin

c or

tho-

ph

osph

ate,

pH

7.5)

0.22

9

0.30

5—

0.16

60.

064

0.22

60.

160

1.41

0.13

20.

238

0.10

40.

052

0.32

40.

480

0.15

00.

056

0.04

00.

025

0.04

40.

113

0.05

60.

036

0.05

60.

067

0.11

80.

111

25 0.19

00.

271

Loop

7

(ble

nded

or

tho-

ph

osph

ate,

pH

7.5)

2.12

0

0.28

7

0.56

30.

074

0.13

40.

312

0.27

40.

288

0.05

0.21

70.

372

0.20

03.

530

0.63

30.

614

0.71

40.

474

0.37

00.

320

0.36

00.

753

0.12

80.

419

0.75

40.

610

0.34

3

26 0.57

40.

707

Loop

B

(ble

nded

or

tho-

ph

osph

ate)

2.73

0

2.14

0

2.33

03.

240

2.72

02.

940

0.50

41.

430.

597

0.96

41.

140

0.04

01.

450

1.13

00.

332

0.17

20.

184

0.35

40.

580

0.38

40.

434

1.10

00.

040

0.84

00.

290

0.43

1

261.

096

0.96

5

— in

dica

tes

no d

ata

colle

cted


control to the treated copper levels, data after stabilization show a more distinct difference. The ratios of standard deviations to mean copper levels from all five copper loops also display this lower variability after stabilization, as follows:

Catskill Delaware copper loops, ratio of standard deviation to mean for copper levels

Loop number Days 1-322 Days 230-322345678

1:31:11:11:1

1:0.51:1.5

1:6 1:1 1:2 1:2 1:1 1:2

The treatments tested in copper Loops 6 and 7 appear to provide the best overall reduction in both copper levels and variability.

Catskill Delaware Pipe Racks, Lead-Soldered Copper Loops. Copper and lead levels were measured over a period of 46 weeks from August 22,1991, through July 9, 1992, from the five lead-soldered copper loops. These data are displayed in Table 4.13 and Figures 4.37 through 4.42 and are summarized below.

Loop Number of number Treatment samples3 Control 264 pH 7.5 245 Zinc ortho-

phosphate 256 Zincorthophos-

phate, pH 7.5 257 Blended orthophos-

phate, pH 7.5 268 Blended ortho-

phosphate 26

Weeks 1-46,lead levels from

soldered copper loops (ug/L)

Mean Median Minimum Maximum0.0310.058

0.0260.043

0.0080.017

0.0930.229

0.024

0.078

0.073

0.133

0.011

0.015

0.043

0.016

0.005

0.005

0.005

0.005

0.098

0.700

0.420

1.460


0.1

0.09

0.08

0.07

1b 0.06fA

J 0.05

1 0.04

0.03

0.02

0.01

Lead-soldered copper Loop 3 (control)

0.24

0.22 -

0.2

0.18

0.16

I3 0.14E/T

"3 0.12_u^ 0.1

0.08

0.06

0.04

0.02

0

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

_____ Lead-soldered copper Loop 4 (NaOH)_________

j——i J___L08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92

DateFigure 4.37 Total lead levels, Catskill Delaware lead-soldered copper Loops 3 and 4


0.11

0.1

0.09

0.08

0.07

rf °-06

£ 0.05

0.04

0.03

0.02

0.01

0

0.8

0.7

0.6

sJ 0.500£C/f

13 0.4•a

jj 0.3

0.2

0.1

Lead-soldered copper Loop 5

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date


08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Figure 4.38 Total lead levels, Catskill Delaware lead-soldered copper Loops 5 and 6



I

0.20.190.180.170.160.150.140.130.120.11

0.10.090.080.070.060.050.040.030.020.01

0

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date


JL J U

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92

DateFigure 4.39 Total lead levels, Catskill Delaware lead-soldered copper Loops 7 and 8



I

uao U

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

32.82.62.42.2

21.81.61.41.2

10.80.60.40.2

0


08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Figure 4.40 Total copper levels, Catskill Delaware lead-soldered copper Loops 3 4


a

2.6

2.4

2.2

2

1.8

1.6


•5 1.2I ex ia '

0.8

0.6

0.4

0.2

0

1.51.41.31.21.1

10.90.80.70.60.50.40.30.20.1

0

I_wHIU

08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date


08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

Figure 4.41 Total copper levels, Catskill Delaware lead-soldered copper Loops 5 and 6


3.5

3

2.5

w13

L

0.5


08/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92Date

3.5Lead-soldered copper Loop 8

2.5

8, 6

0.5

008/10/91 09/19/91 10/29/91 12/08/91 01/17/92 02/26/92 04/06/92 05/16/92 06/25/92

DateFigure 4.42 Total copper levels, Catskill Delaware lead-soldered copper Loops 7 and 8

Weeks 1-46, copperlevels

.LAMJp rtUUIUtl Ul ————————

number Treatment samples Mean3456

7

8

ControlpH7.5Zinc orthophosphateZinc orthophos

phate, pH 7.5Blended ortho-

phosphate, pH 7.5Blended ortho-

phosphate

262425

25

26

26

2.010.611.01

0.19

0.57

1.10

Median1.940.440.83

0.11

0.37

0.72

Minimum1.100.070.08

0.03

0.05

0.04

Maximum2.782.742.37

1.41

3.53

3.24

Lead levels from the control loop (Loop 3) were erratic throughout the study period, and no discernible trend in the data could be detected. Loop 4 lead levels exhibited an initial increase for the first fourmonths of operation followed by a steady decrease. Levels appeared to stabilize by the end of February 1992, approximately 180 days after the start of operations. The lead levels measured after day 180 were similarto those measured at the beginning of the study. Loop 5 lead levels displayed a generally decreasing trend until April 1992, after which several very high levels were measured. These high lead levels obscured detection of an Overall trend for the entire data set. By June 1992, however, lead levels were similarto those measured in April 1992. The high lead levels may have been caused by seasonal water quality changes or operational changes in the pipe rack apparatus. Loop 6 displayed an overall negative (decreasing) trend in the data that was significant at the .005 p level. These levels stabilized by April 1992 (230 days into the study), after which the estimated trend line was very flat. The estimated trend lines for Loop 6 are shown in Figures 4.43a and 4.43b. Loop 7 also exhibited ahighly significant decreasing trend in lead levels (Spearman r=-.64, p level = .0004); however, stabilization occurred after approximately 180 days (see Figures 4.44a and 4.44b). Finally, lead levels from Loop 8 were generally very low, with several high values measured at various times during operation. No trend in these data could be detected.

Results for copper levels from these loops were as follows. Loop 3 (control loop) displayed inconsistent copper levels throughout the 322-day study period. No trend was observed in these data. Loop 4 exhibited relatively stable copper levels for several months (with the exception of one very high value inFebruary 1992), followed by a decrease in levels. Copper levels appeared to be increasing slightly during the last 2 months of operation, but additional data points would be needed to verify this hypothesis.Loop5exhibitedadecreasingtrendincopperlevels(Spearmanr= -.39, p level < .05), which may have stabilized after 180 days (see Figures 4.45a and 4.45b). A strong decreasing trend in copper levels was observed with Loop 6, which received water treated with zinc orthophosphate and caustic soda to adjust the pH to 7.5. As with Loop 5, copper reached relatively stable levels after 180 days. Loop 7 displayed stable, relatively low copper levels from the beginning of the study. After approximately 180 days, these levels increased but remained stable at a slightly


oo

0.8

0.7

0.6

0.5

0.4

0.3

1 0.2

0.1

0-0.1

-0.20 50 100 250 300150 200

DayFigure 4.43a Estimated trend line for lead levels, Catskill Delaware lead-soldered copper Loop 6, all data

350

0.03

0.025

0.02«JE 0.015wT1 o.oi8 0.005

0

-0.005

-0.01220 240 260 280 Day

300 320 340

Figure 4.43b Estimated trend line for lead levels, Catskill Delaware lead-soldered copper Loop 6, days 230 through 322


U.3

0.45

0.4

0.35

1b 0.3

rf °-25

1 0.2^^ i

3 0.1

0.05

0

-0.05 -0.1

.

-

-

•

•

i j

~~*~~ ——— ——— -—*^-~——-———-____

"•' T — ——— ~~~ —— —— ,——______• ••*••• • •• •

•

50 100 150 200 250 300 35Day

Figure 4.44a Estimated trend line for lead levels, Catskill Delaware lead-solderedcopper L

0.5 0.45

0.40.35

|> 0.25 rf 0.21 0.15^ 0.1

TO

j 0.05 0

-0.05-0.1

-0.15 -°'2l

.oop 7, all data

•i" -

.

.

.•

• ———— ——— ——— ——— ~m ———— m '

.-•

50 175 200 225 250 275 300 325 35Day

Figure 4.44b Estimated trend line for lead levels, Catskill Delaware lead-soldered copper Loop 7, days 180 through 322

2.6 2.42.2

2tJ 1.8 I 1-64 1-4 I 1.2

10.8 0.6 0.4 0.2

0 -0.2

a.

I


50 100 150 200 Day

250 300 350

Figure 4.45a Estimated trend line for copper levels, Catskill Delaware lead-soldered copper Loop 5, all data

1.8

1.6

1.4

u>13J8 0.8(_,<oS 0-6

3 0.4

0.2

0

-0.2150 175 200 225 250

Day275 300 325 350

Figure 4.45b Estimated trend line for copper levels, Catskill Delaware lead-soldered copper Loop 5, days 180 through 322

higher level. Results from Loop 8 were essentially similar to those from Loop 6. As with lead levels from the lead loops and copper levels from the copper loops, all of the lead-soldered copper loops exhibited high copper levels during February 1992.

AWilcoxonmatehed pairs evaluation of the difference inleadlevels between the control loop (Loop 3) and the treated loops (Loops 4 through 8) after day 230 of the study indicated that only Loop 6 produced lead levels that were significantly lower than those of the control loop (p level < .05). A representation of the lead data from days 230 through 322 is displayed in Figure 4.46a. Lead levels from Loop 6 displayed much less variability than those of the other loops. The effectiveness of this treatment is obscured when lead data from the entire study period are evaluated. Figure 4.46b is abox and whiskers plotof lead levels for Loops 3 through 8 for days 1 through 322. Loop 8 lead levels have a much wider range than those of the control loop, as do several of the other treated loops, when all of the data are incorporated in the assessment. The ratios of the standard deviation to the mean for lead levels from all five loops are as follows:

Catskill Delaware lead-soldered copper loops,ratio of standard

__ deviation to mean for lead levelsLoop number

345678

The ratio for Loop 6 is for days 230 through 322.A Wilcoxon matched pairs evaluation of copper levels indicated that all of

the treated loops produced levels that were significantly lower than those of the control loop, both when all of the data were evaluated and when data from days 180 through 322 were evaluated. Figures 4.47a and 4.47b display box and whiskers plots of copper levels for these two time periods. The treatment tested in Loop 6 appears to have provided the best overall reduction in copper levels. Although the statistical test indicates a significant difference in the copper levels, the amount of inherent variability in the data, as evidenced by the wide standard deviations for most of the loops, reduces confidence in the effectiveness of these treatments. The ratios of standard deviation to the mean for copper levels were as follows:

Days 1-3221:11:11:11:0.41:0.81:0.4

Days 230-3221:11:21:11:11:0.41:0.4


tJsM

13

-a(33uJ

l.O

1.41.2

10.80.60.40.2

0-0.2-0.4-0.6-0.8

-11 0

••---.-

cga * ^ ^. \\

J

-

-

-

-

FJi i

• Mean

en 2 StandardError



Figure 4.46a Box and whiskers plot of lead levels, Catskill Delaware lead-soldered copper loops, days 230 through 322

i.t

1.2

1

0.8

^ 0-6

e o.4c/T

13 0.2 u ^ 0J -0.2

-0.4

-0.6

-0.8 1

•

•

-

•

-

: * * * o--.-

o ^ E

.-•••

i••

~•

.Mean

cn 2 StandardError



Figure 4.46b Box and whiskers plot of lead levels, Catskill Delaware lead-soldered copper loops, all data

u

43.5

32.5

1.5

10.5

0-0.5

-1

-1.5 _o

-

-

Q

••

•••

i]

i ii i

Q •j 3i

---

H :-

~•

|Mean

1=1 2 StandardError


Loop 3 Loop 4 Loop 5 Loop 6 Loop 7 Loop 8Figure 4.47a Box and whiskers plot of copper levels, Catskill Delaware lead-soldered copper loops, all data

i3.5

3

2.5

^ 25£ 1.5<u| 1

& °'5o0 0

-0.5

-1-1.5

•

•

G-

•

••••-

0

i 1 Hi L a i i i i

---_

-j

•

-----

• Mean

c=t 2 StandardError


Loop 3 Loop 4 Loop 5 Loop 6 Loop 7 Loop 8Figure 4.47b Box and whiskers plot of copper levels, Catskill Delaware lead-soldered copper loops, days 180 through 322

Days 1-322

1:51:0.71:21:11:11:1

Days 180-322

1:51:0.71:21:21:21:1


Catskill Delaware lead-soldered copper loops,ratio of standard

deviation to mean for copper levels

Loop number

345678

Operational ConsistencyThe Croton pipe racks were operated for a total of 264 days (38 weeks), and

the Catskill Delaware racks were operated for 322 days (46 weeks). The pipe racks were checked weekly and the flow was manually turned off once per week. Field water quality parameters were also checked weekly and adjustments were made to chemical feed pumps if necessary.

Occasional leaks from pipes, fittings, rotameters, and static mixers were repaired during preparation. Static mixers were eventually eliminated because of clogging caused by sand and silt in the raw water. In addition, the pumps used in the racks required frequent maintenance during the study and the pressure regulators imposed too much head loss in the rack.

Distribution System Correlation Studies________

The purpose of the pipe rack operations at Contra Costa, Fort Worth, and Portland was to assess the time required for lead and copper levels to stabilize and to evaluate the variability in lead and copper levels measured from three identical test loops. The following sections summarize the pipe rack data results and evaluations for each of these utilities.

In addition to the construction and operation of the AWWARF pipe rack, these utilities completed several rounds of home tap monitoring. These data were generated in order to complete an evaluation of the correlation between lead and copper levels measured from the pipe rack and lead and copper levels measured in the system. The discussion of the relationship between these two groups of data has been organized into three main subsections:

1. an explanation and comparison of the summary statistics for both the pipe rack and the home tap samples

2. a summary of the statistical significance of the difference in lead and copper levels between the pipe rack and the home tap samples

3. an evaluation of the correlation between lead and copper levels measured from the pipe rack and from the home tap samples


Table 4.14a Summary of water quality data, Contra Costa AWWARF pipe rack

InfluentNumber of observationsAverage MinimumMaximumStandard deviation

Loop 1 Number of observationsAverage MinimumMaximumStandard deviation


Loop3 Number of observationsAverage MinimumMaximumStandard deviation

Lead (M9/L)

48.0002.800 0.000

26.8003.639

48.00024.478

0.000134.36021.652

48.00015.184 2.690

119.20020.185

48.00013.700 2.070

99.20014.731

Copper Alkalinity Ammonia (mg/L) (mg CaCO/L) (mg/L)

48.0000.029 0.0000.1300.021

48.0000.260 0.0000.6210.103

48.0000.266 0.0000.7360.116

48.0000.276 0.1800.5700.100

48.00067.729 41.00095.00011.543

48.00071.083 60.00090.0008.036

48.00071.229 62.00088.000

7.776

48.00069.542 48.00089.00010.553

46.0000.046 0.0090.1300.020

46.0000.063 0.0000.1700.037

46.0000.064 0.0000.1800.038

46.0000.062 0.0000.1600.038

Calcium (mg/L)

47.00017.617 13.00034.000

4.123

47.00017.583 13.00032.400

4.022

46.00017.313 0.000

32.4004.793

47.00017.749 13.00037.600

4.480

Free chlorine (mg/L)

47.0000.039 0.0100.1000.022

47.0000.019 0.0000.0500.008

46.0000.019 0.0100.0400.007

46.0000.017 0.0100.0400.007

Total chlorine (mg/L)

47.0000.184 0.0200.6000.117

47.0000.033 0.0000.0600.012

46.0000.037 0.0200.0800.013

46.0000.036 0.0200.1100.014

Contra Costa Water District

Pipe Rack Water Quality Data Summary and Statistical EvaluationThe Contra Costa Water District constructed one AWWARF pipe rack with

three replicate copper loops soldered with 50:50 lead-tin solder. A summary of the water quality data collected from each of the replicate loops as well as from the influent running water is shown in Tables 4.14a and 4.14b. A complete set of the data is included in Appendix G. The influent waterexhibitedawide range of water quality characteristics throughout the study period. Conductivity varied between 370 and 800 umhos/cm during this period, and pH ranged from 6.8 to 8.8. Dissolved oxygen levels were also highly variable, with influent running levels measuring between 7.9 and 16 mg/L. Figures 4.48 through 4.50 display the incoming water quality characteristics for several parameters throughout the 331-day study period. Conductivity, alkalinity, and pH reached their highest levels during the summer of 1991. DissolvedoxygenlevelswerehighestbetweenNovember 1991 and April 1992, which would be expected with the lower water temperatures.


Table 4.14b Summary of water quality data, Contra Costa AWWARF pipe rackDO Orthophosphate

(mg/L) (mg/L) pHInfluent

Number of observationsAverage MinimumMaximumStandard deviation



LoopS Number of observationsAverage MinimumMaximumStandard deviation

41.00010.115 7.910

15.9502.279

41.0009.764 7.140

15.7002.352

41.0009.821 7.080

16.5602.478

41.0009.738 7.060

15.7602.402

44.0000.100 0.1000.1000.000

44.0000.100 0.1000.1000.000

44.0000.100 0.1000.1000.000

44.0000.100 0.1000.1000.000

48.0008.026 6.8308.8000.472

48.0008.166 7.4008.7500.342

48.0008.198 7.4208.8000.332

48.0008.161 7.2808.8000.373

Conductivity (umhos/cm)

47.000654.915 370.000800.000

80.903

47.000657.128 375.000850.000

76.065

47.000657.021 410.000800.000

68.910

47.000669.149 550.000900.000

67.943

Temperature (°C)

48.00017.967 8.000

27.0004.707

48.00017.956 6.000

30.0004.937

48.00017.985

6.00031.000

4.936

48.00017.992 6.000

32.0005.016

Turbidity (ntu)

41.0000.383 0.1103.7000.568

41.0000.341 0.1103.5000.509

41.0000.276 0.1102.6000.378

41.0000.268 0.1202.6000.377

Average standing lead levels measured from the three replicate loops were 25.0,15.2, and 13.7 ug/L, with maximum values of 132,117, and 97 pg/L. Average standing copper levels were 0.27 mg/L for two of the replicate loops and 0.28 mg/L for the third loop, with maximum values of 0.62,0.74, and 0.57 mg/L. Standing lead and copper levels measured throughout the study are displayed in Figure 4.51. Both the lead and the copper data exhibited nonnormal distribution.

Copper levels displayed a definite downward trend until July 1991, or approximately 50 days into the pipe rack operation, after which the levels appeared to stabilize at between 0.2 and 0.3 mg/L. Lead levels did not display the same type of trend, and occasional high lead levels were measured at various times throughout the study period. Estimated trend lines for lead and copper levels from each of the three loops are displayed in Figures 4.52 and 4.53, respectively. Spearman rvalues for lead levels were significant (Spearman r = +.43, -.43, and +.42). These values indicate that there is a slightly positive trend in lead levels from Loops 1 and 3 and a slightly negative trend in Loop 2. Copper levels exhibited a significantly negative trend for the Speannan correlation coefficient. Visual examination of the data indicates that copper levels in all three loops may have stabilized approximately 50


100

90

8°

toO70

3? 60e

50

40

30 5/6/91 I 8/14/91 I 11/22/91 I 3/1/92 I6/25/91 10/3/91 1/11/91 4/20/92

Date

850

800

750E

-SJ 700C/3

I3.

65°

>. 600

550

1 500 U

450

400

3505/6/91 I 8/14/91 I 11/22/91 I 3/1/92 I

6/25/91 10/3/91 1/11/91 4/20/92Date

Figure 4.48 Influent alkalinity and conductivity levels, Contra Costa pipe rack


I 7£ Tex 7

7

7

5/6/91 I 8/14/91 ' 11/22/91 ' 3/1/92 '6/25/91 10/3/91 1/11/91 4/20/92

Date

2O,E

28272625242322212019181716151413121110987

5/6/91 ' 8/14/91 ' 11/22/91 ' 3/1/92 '6/25/91 10/3/91 1/11/91 4/20/92

Date Figure 4.49 Influent pH and temperature levels, Contra Costa pipe rack


0.7

0.6

0.5

•g1 0.3

1 H 0.2

0.1

05/6/91 I 8/14/91 I 11/22/91 I 3/1/92 I

6/25/91 10/3/91 1/11/91 4/20/92Date

ec

ot/j to

3

17

16

15

14

13

12

11

10

9

8

75/6/91 I 8/14/91 I 11/22/91 I 3/1/92 I

6/25/91 10/3/91 1/11/91 4/20/92

Date Figure 4.50 Influent total chlorine and dissolved oxygen levels, Contra Costa pipe rack

0.8

0.7

0.6

If 0-5

<u

Ia.

0.4

0.3

0.2

0.1

00

50

+ Loop 1 O Loop 2 A Loop 3

100150

Time, days

200250

300350

<u

03

2

+ Loop 1O Loop 2A Loop 3

150 250 350

Time, days Figure 4.51 Standing lead and copper levels, Contra Costa pipe rack

; 74 Development of a Pipe Loop Protocol

3.

wf"3

140

120

100

80

60

40

20

0

Loop 1

••• mm,50 100 150 200 250 300 350

DayLoop 2

120

100

? 80(/)

Ji 60"<S

40

20

0 50 100 150 200 Day

250 300 350

^3. c/Tu>U•a

JS

itu

120

100

80

60

40

20

n

-

•

1 •

.

350 Day

Figure 4.52 Estimated trend lines for lead levels, all data, Contra Costa Water District


0.8

0.7

_, 0.6

6 0.5«T| 0.4

J 0.3a 3 0.20.1

0

Loop 1

0 50 100150 200 250 300 350Day

0.8

0.7

E 0.5

| 0.4

§, °'3 o A 2

0.1

0

Loop 2

50 100 150 200 250 300 350 Day

0.8

0.7

^°'66 0.5cn"

1 0.4 u^0.3

§0.2

0.1

Loop 3

50 TOO 150 200 Day

250 300 330

Figure 4.53 Estimated trend lines for copper levels, all data, Contra Costa Water District


days into the study. Lead levels appear to have stabilized after 150 days in Loops 2 and 3. To evaluate this hypothesis, copper levels from days 50 through 331 and lead levels from days 150 through 331 were used to estimate trend lines. Copper levels still exhibited a significant downward trend from days 50 through 331 (Figure 4.54); however, the range of values was relatively narrow (0.18 through 0.31 mg/L Cu). Lead levels appear to have stabilized between days 150 and 331 based on the estimated trend lines, which were not significant (Figure 4.55).

The variability in lead levels between each of the replicate loops was evaluated using a Wilcoxon matched pairs test. On the basis of all the data, the lead levels from Loops 2 and 3 were not significantly different from each other, however, Loop 1 lead levels were significantly different from those of Loops 2 and 3. Figure 4.56 is abox and whiskers plot of these lead data. On the basis of lead level data from days 150 through 331, all three loops were found to be significantly different from each other, according to the Wilcoxon matched pairs test. The copper levels from all three loops were not significantly different from each other. The ratio of the standard deviation to the mean for lead levels was approximately 1:1, and the ratios of copper levels ranged from 1:2 to 1:3.

Operational ConsistencyThe Contra Costa pipe rack was operated for atotal of 331 days, or48 weeks,

betweenMay 1991 andApril 1992. The pipe rack was checked weekly, at which time field water quality parameters were measured and standing samples were collected. No major complications or problems were reported during operation of the pipe rack, with the exception of minor leaks that required repair during the startup phase of the project.

Distribution System Data EvaluationSummary Statistics. Home tap samples were collected at approximately

80 homes at 6-week intervals from April 1991 throughMarchl992,foratotalofnine separate sampling events. Two standing samples were collected: a 250-mL sample followed by a 750-mL sample. Standing samples were collected from homes built between 1982 and 1987 that contained copperpipingjoined with lead solder. The total number of houses where both 250- and 750-mL samples were collected and analyzed for lead and copper levels was as follows:

Sample Date Number of period sampled houses

1 4/29/91 762 6/10/91 743 7/22/91 774 8/25/91 765 10/13/91 776 11/25/91 757 1/5/92 758 2/17/92 759 3/30/92 76

All data 681

The majority of samples was collected on or around the dates shown.

u.o

0.7

li 0'6E 0.5w"

| 0.4<u£0.3o.u 0-2

0.1

°0

" .- . .• . — ' —— * — *• ^" — ••. . * — , _ , **"^_«_

• • '

50 100 150 200 2^0 300 35 0Day

0.8

0.7

6 0.5

| 0.4J-

u °-20.1

n .

Loop 2

:.

• « B • • ••

50 100 150 200 250 30(5 350 Day

0.8

0.7

6 0.5 wf1* 0.4

S 0.3

§-0.2

0.1

0 0

Loop 3

100 250 300 350T30 200 Day

Figure 4.54 Estimated trend lines for copper levels, days 50 through 331, Contra Costa Water District


140

120

100

f 80"SJB 60"S

$ 40

20

0150

Loop 1

200 250 Day

300 350

140

120

100

* 80CA

I 60"3

J3 40

20

0

Loop 2

150 200 250 Day

300 350

£

140

120

100

80

60

40

20

0150

Loop 3

200 250 Day

300 350

Figure 4.55 Estimated trend lines for lead levels, days 150 through 331, Contra Costa Water District

50

40

30

* 20.S3 <u

10

0 -

-10 -


Loop 1 Loop 2 Loop 3 Figure 4.56 Box and whiskers plot of lead levels, Contra Costa Water District

The lead and copper levels measured from these samples are listed in Appendix G. Lead levels from the 250-mL samples ranged from <2 to 265 ug/L, with an average of 7.8 ug/L. Lead levels from the 750-mL samples were lower, ranging from <2 to 112 ug/L, with an average of 3.7 ug/L. Forty-four of the 250-mL samples (6.5 percent of the total) had lead levels higher than the regulatory action level of 15 ug/L; however, lead levels from all of the 750-mL samples were below the action level. The difference in the lead levels measured between these two samples indicates that brass faucets and the connective piping to the faucets may be leaching higher concentrations of lead into the water than the remainder of the premise piping in the houses. Copper levels were essentially the same for both the 250- and 750-mL standing samples collected at the tap (0.003 to 0.42 mg/L) and were well below the action level of 1.3 mg/L.

Lead and copper results from the 250- and 750-mL samples were also combined to obtain calculated 1,000-mL levels for these metals. These calculated results werecompared to the actionlevels specified in the final Lead and Copper Rule. Using calculated 1,000-mLleadandcopperlevels,the90thpercentilelevelsforthese metals were as follows:


Lead7.19.48.47.58.26.45.26.37.3

Copper0.090.230.150.200.220.210.200.180.19

Calculated 1,000-mL sample __ 90th percentile levels

Sample period123456789

All 90th percentile levels were below the action levels specified in the final Lead and Copper Rule.

To compare the home tap sample data with lead and copper levels measured from the pipe rack, the pipe rack data were also divided into nine sample periods that coincided with the nine sampling events in the distribution system. Pipe rack data were collected weekly for approximately 47 weeks from three replicate test loops. Previous evaluation of the pipe rack data indicated that two of the three replicate loops provided metals levels that were statistically the same (i.e., one of the loops had lead levels thatwere statistically differentfrom the othertwo). Therefore, the comparison of pipe rack data to distribution system tap data was completed using only data from the two similar replicate loops from the pipe rack. Results from the pipe rack were then grouped into nine sample periods based on their proximity to the distribution system sampling period. Based on data from two of the three replicate loops, the number of lead and copper samples from the pipe rack for each of the sample periods was as follows:

Pipe rackstudy period Number of Number of

Sample periods (dates) lead samples copper samples

1 5/7/91-5/14/91 8 82 5/21/91-6/25/91 10 93 7/2/91-8/7/91 10 104 8/14/91-9/11/91 10 105 9/18/91-11/6/91 16 166 11/13/91-12/11/91 10 107 12/18/91-1/22/92 12 128 1/29/92-3/4/92 12 129 3/11/92-4/1/92 8 __8

All data 96 95


Table 4.15 Summary statistics for lead and copper levels for pipe rack and distribution system tap samples, Contra Costa Water District

Average levels

Tap samples

Sample period

Lead123456789

Copper123456789

Pipe rack

18.514.26.9

29.110.222.512.212.07.3

0.560.350.230.260.260.240.230.210.21

250 mL

13.38.98.37.39.17.25.06.05.1

0.120.140.090.120.120.120.110.100.11

Calculated 750 mL 1,000 mL

3.44.53.63.74.93.03.42.94.3

0.120.130.090.130.140.140.120.110.12

6.05.64.84.65.94.13.83.64.5

0.120.130.090.130.140.130.120.110.12

Pipe rack

16.516.85.5

32.14.5

34.65.83.74.0

0.080.120.030.020.020.030.040.010.01

Standard deviation

Tap samples

250 mL

38.013.115.612.916.213.05.6

13.65.8

0.050.070.040.060.050.050.050.040.05

750 mL

3.95.03.43.6

12.62.35.52.17.1

0.060.070.050.070.070.070.070.060.06

Calculated 1,000 mL

12.06.35.65.5

10.84.44.94.55.9

0.060.070.050.070.060.060.060.060.06

Pipe rack

13.46.64.2

12.510.013.411.713.16.8

0.540.350.230.260.270.230.230.210.21

Median levels

Tap samples

250 mL

5.04.74.64.55.73.73.43.13.7

0.110.130.100.110.130.130.110.100.11

Calculated 750 mL 1.000L

2.02.52.02.12.72.02.02.02.0

0.110.130.090.130.140.130.130.100.12

2.93.53.13.03.52.82.42.32.8

0.100.130.090.130.150.130.120.100.12

A comparison of the means, medians, and standard deviations for lead and copper levels from both the tap samples and the pipe rack samples is displayed in Table 4.15. The average and median lead and copper levels measured from the pipe rack were generally higher than those from the distribution system tap samples. This difference can easily be seen in Figures 4.57 and 4.58. With the exception of sample period 3, mean and median lead levels from the pipe rack were greater than those of either the 250- or the 750-mL samples collected at the tap. Copper levels from all sample periods were higher in the pipe rack than hi the home tap samples. The standard deviations for all lead and copper levels measured from the tap samples and the pipe rack are shown in Figures 4.59 and 4.60. The upper and lower boundaries of the ±2 standard deviation lines shown for each sample period incorporate 95 percent of the data for that period. The wider the band, the greater Hie variation in lead levels measured for that sample period. Lead levels from the 750-mL samples displayed less variation than those from the 250-mL samples. For sample periods 2, 4, and 6, the pipe rack data exhibited a larger variation in lead levels than was seen in either the 250- or 750-mL samples. The variation in copper levels was similar for the 250- and 750-mL samples, and the standard deviation of the copper levels from the pipe rack after stabilization (sample periods 3 through 9) was much lower than that of the tap samples. The variation in lead and copper levels can also be evaluated based on the ratio of the standard deviation divided by the mean. The higher the ratio,

<ujj•30)

323028262422201816141210

86420

Average

n 5 r4 6

Sample period

• Rack+ 750 mL

e Calculated 1,000 mL

250 mL

Median

<u

1413121110987654321

2468

Sample periodFigure 4.57 Average and median lead levels, Contra Costa Water District


I

a

1.31.21.1

10.90.80.70.60.50.40.30.20.1

0

Average

• Rack+ 750 mLo Calculated 1,000 mLA 250 mL

\ 5 \ 4 6

Sample period

Median0.6

0.5

0.4

0.3

a, 0.2ex o U

0.1

0

• Rack + 750 mLo Calculated 1,000 mL

250 mL

1 I 3 I 5 1 7 I 9 2468

Sample periodFigure 4.58 Average and median copper levels, Contra Costa Water District

141)

120

100

a 6042 4°u> 20U-" o^ -20>J -40

-60-80

-100

140

120

100

3- 60

42~ 40 <O > 20

— o§ -20

>-J -40-60

-80

-100

140

120

100

t-J 80

SL 60

oo" 40

> 20i -:-40

-60

-80 -inn

•

.

' M I 1 I I: C] t T T T-••12345

Sample period

-

.

'• * * * * "1 -5

--

•

12345Sample period

B~ r

- J T T * I

250 mL ]

r * I * !

6789

750 mL J.

- * * i :--i•

6789

Pipe rack j•i.

1 * * * ]

t --

| Meani — i 2 Standard

ErrorT 2 Standard

Deviation

| Mean, — ! 2 Standard

ErrorT 2 Standard

Deviation

• Mean, — , 2 Standard

ErrorT 2 Standard

Deviation

123456789

Sample period

Figure 4.59 Means and standard deviations for lead levels by sample period, Contra Costa Water District


v.y 0.8

8 0.675 °-5Jl °-4fc 0.3a 0.2OU 0.1

0

0.90.8

(J 078 0.6

*i

Ji °-41-1 Q3

§0.2 U 0.1

0-0.1

0.90.8

8 0.6C/T « c

7ju 0.4^Hg 0.3S 0.2OU 0.1

0_n i

; 250 mL "r •-•-

^ A " i J, A 1 1 1 I j

123456789Sample period

.

L 750 mL---.

- I T n, i I 'm D] 1 C3 Da D3 G3 Q] ±i

123456789

Sample period

Pipe rack \n|l 1

L L J

[ 1rL J T ^ J, T T

T T T * "*^.- ^

:

• Meani — i 2 Standard

ErrorT 2 Standard

Deviation

B Meani — i 2 Standard

ErrorT 2 Standard

Deviation

| Mean

i — i 2 StandardError


123456789 Sample period

Figure 4.60 Means and standard deviations for copper levels by sample period, Contra Costa Water District


Table 4.16 Ratios of standard deviation to mean for average lead and copper levels, Contra Costa Water District

Evaluationperiod

123456789

Piperack

1:11:0.81:11:11:21:0.61:21:31:2

Lead Copper

Tap samples250 mL

1:0.41:0.71:0.51:0.61:0.61:0.61:0.91:0.41:0.9

750 mL

1:0.91:0.91:11:11:0.41:11:0.61:11:0.6

1,OOOmL

1:0.51:0.91:0.41:0.81:0.61:0.91:0.81:0.81:0.8

Piperack

1:71:31:8

1:151:11

1:81:6

1:301:42

Tap samples250 mL

1:21:21:21:21:21:21:21:21:2

750 mL

1:21:21:21:21:21:21:21:21:2

1,OOOmL

1:21:21:21:21:21:21:21:21:2

the less variability observed in the data. Table 4. 16 contains a summary of these ratios for mean lead and copper levels. The ratios for lead levels from the pipe rack ranged from 1 :0.6 to 1 :3, and for calculated 1 ,000-mL samples the ratios ranged from 1 :0.5 to 1 : 1 . In other words, the variation in lead levels measured from home tap samples was generally greater than that of the levels from the pipe rack. Copper levels showed much smaller variations than did the lead levels. Pipe rack copper data exhibited ratios ranging from 1:3 to 1:42, whereas ratios from the tap samples were all 1:2.

Finally, frequency distributions for lead and copper levels were calculated to evaluate whether these sample groups representednormal or nonnonnal distributions and whether the data distributions were similar. The lead levels measured from standing tap samples displayed nonnonnal distributions, as seen in the frequency distribution curves for calculated 1,000-mL samples in Figure 4.61. Copper levels were closer to a normal distribution (Figure 4.61). The lead and copper level distributions for pipe rack data can be seen in Figure 4.62. These data are nonnormally distributed, which suggests that alternative nonparametric tests may be more appropriate to use for evaluating these data. Parametric tests are applicable to data that are normally distributed or that contain a large number of observations

Statistical Difference in Metals Levels. To determine if the mean or median lead and copper levels measured at the tap were statistically different than those of the pipe rack samples, a nonparametric Wilcoxon matched pairs test was performed using the average and median lead and copper levels for all nine sample periods. Because the lead level data from the pipe rack stabilized after 150 days (sample period 5) and the copper levels stabilized after day 50 (sample period 3), the comparison of lead values was also made using values from sample periods 5 through 9, and for copper levels from sample periods 3 through 9.

400

350

300

250 oS 2003

I 150

100

50

0


0.

— Expected

10. 20. 30. 40. 50. 60. 70. 80. 90. 100.

Lead level category (upper limits)

— Expected

.10 .15 .20 .25 .30

Copper level category (upper limits).40

Figure 4.61 Frequency distributions for calculated 1,000-mL lead and copper samples, Contra Costa Water District


20

18

16

14

12

10

8

6

4

2

0, 80. 90. 100— Expected

Lead level category (upper limits)

— Expected

Copper level category (upper limits)Figure 4.62 Frequency distributions for pipe rack lead and copper samples, Contra Costa Water District

Mean and median lead levels for the pipe rack were both found to be significantly different from the 250-mL, 750-mL, and calculated 1,000-mL tap lead levels atthe .05 p level using the Wilcoxonmatched pairs test These results are listed in the tables of p levels below.

Wilcoxon p levels for mean lead levels

Sample periods 1-9 Sample periods 5-9

Pipe rack versus 250 mL .015 .043Pipe rack versus 750 mL .008 .043Pipe rack versus 1,000 mL .008 .043

Wilcoxon p levels for mean copper levels



These results indicate that the means of the lead levels measured from the pipe rack and from the 250- and 750-mL samples at the tap are significantly different at the .05 p level. A p level of <.05 suggests that there is a probability of >95 percent that values are significantly different The Wilcoxon matched pairs test comparing the pipe rack mean copper levels with the 750-mL mean copper levels resulted in a p level of .008, or .8 percent. Therefore, there is a 99.2 percent probability that the lead levels measured from these two groups were different from each other. Median lead and copper levels exhibited similar results.

In summary, Hie metals levels measured from the pipe rack are significantly different from the metals levels measured from standing tap samples in the distribution system.

Correlation of Lead and Copper Levels. Lead and copper levels from the pipe rack were also correlated to the standing tap levels. The results of this evaluation are reported as a correlation coefficient, or r value. A perfect positive correlation is expressed by rvalues of+1.00; i.e., low values for one group correspond to low values for the other group. In a perfect negative correlation, the rvalue would be -1.00, and low values for one group would correspond to high values for the other group. The correlation of the lead levels from the pipe rack to lead levels from the standing tap samples was completed using average and median lead levels from sample periods 5 through 9. This is the interval during the study in which the lead levels had stabilized in the pipe rack. The Spearman r values computed for the correlation of average lead levels from the pipe rack versus levels from the tap samples for sample periods 5 through 9 were as follows:


o int—

J3 3

1

5 7.5 10 12.5 15 17.5 20 22.5 25

Lead levels (pipe rack), pg/L

7.5 10 12.5 15 17.5 20 22.5 25

Lead levels (pipe rack), jig/LFigure 4.63 Correlation of lead level measurements, Contra Costa Water District

Lead level correlation sample periods 5-9

Spearman r value p levelPipe rack versus 250 mL .00 1.00Pipe rack versus 750 mL -.60 .28Pipe rack versus 1,000 mL -.50 .39

Correlations for median lead levels were similar. The r values for the relationship between lead levels in the pipe rack and lead levels from the 250-mL sample indicated a complete lack of correlation. The correlation between pipe rack lead levels and lead levels from the 750-mL and calculated 1,000-mL samples was negative; i.e., high lead levels from the pipe rack corresponded to low lead levels in the tap samples (seeFigure4.63). Calculated 1,000-mL lead levels from eachhouse were also correlated to average lead levels from the pipe rack for each sample period. Only 2 of the 80 homes had lead levels that displayed a significant correlation (Spearman r = .95, p level < .05) to those of the pipe rack. These results provide little assurance that pipe rack results for lead actually represent distribution system standing lead level results in Contra Costa. The correlation for copper levels was much more promising, however. The correlation of copper levels from the pipe rack to copper levels from standing tap samples was completed using average and median copper levels for sample periods 3 through 9 because copper levels stabilized in the pipe rack during sample period 3. The Spearman r values computed for the correlation of average copper levels from the pipe rack to the tap samples for sample periods 3 through 9 were as follows:

Copper level correlation sample periods 3-9

Spearman r value p levelPipe rack versus 250 mL +.74 .06Pipe rack versus 750 mL +.77 .04Pipe rack versus 1,000 mL +.77 .04

This correlation is much more significantthanthe correlation for lead levels, and the correlation is positive, i.e., high copper levels from the pipe rack correspond to high copper levels from the standing tap samples. The correlation becomes even more significant when average copper levels from sample periods 5 through 9 are used in the evaluation:

Figure 4.64 displays this correlation for sample periods 5 through 9. The equationfor the regressionline indicates that copper levels from the 750-mL standing samples are approximately 0.6 times the copper levels from the pipe rack and copper levels from a calculated 1,000-mL tap sample are approximately 0.4 times the copper levelsmeasured from the pipe rack. Median copper levels showed similar correlations. When copper levels from each of the individual houses were correlated to copper levels from the pipe rack, 10 houses exhibited a significant correlation (p level < .05), with Spearman r values of .7 to .9.

In summary, when lead levels measured from the pipe rack and lead levels measured from standing tap samples are compared, there is essentially no correlation in actual levels. Copper levels from the pipe rack are highly correlated to tap samples, however. Although the actual copper levels measured in the distribution system are lower than those in the pipe rack, there is aproportional relationship that is significant and that provides some degree of confidence that the pipe rack copper data are representative of standing copper level trends from home tap samples.

Fort Worth Water Department

Pipe Rack Water Quality Data Summary and Statistical EvaluationThe Fort Worth Water Department constructed two AWWARF pipe racks,

one with three replicate %-in.-ID(19.05-mm)leadloops and one with three replicate V£-in.-ID(12.7-inm) lead-soldered copper loops. A summary of the waterquality data collected from each of the racks, as well as of the influent running water quality, is shown in Tables 4.17a through 4.18c. A complete set of the data is included in Appendix G. Each of the pipe racks is discussed separately below.

Alta Mesa Lead-SolderedCopperPipeRack. The quality of the influent water can be seen in Figures4.65athrough 4.67. Alkalinity levels ranged from 66 to 128 mg/L CaC03, with pH levels between 7.7 and 8.7. The total chlorine residual entering the pipe rack varied from 0.7 to 3.7 mg/L, and dissolved oxygen was measured from 6.5 to 11.6 mg/L. Average standing lead levels from the three loops were 0.008,0.0104, and 0.008 mg/L, respectively. Average copper levels were 0.55, 0.56, and 0.54 mg/L. Standing lead and copper levels are displayed in Figure 4.68. The distribution of the lead data was nonnormal, whereas the copper level data more closely approached a normal distribution.

Lead levels displayed a somewhat flat trend that approached stabilization after 200 days, with the exception of two periods when somewhat higher levels were measured. These high levels occurred in February and late August 1992. Estimated trend lines for lead levels are exhibited in Figure 4.69. Loops 1 and 3 displayed slightly decreasing trends in the data, whereas no trend was detected inLoop 2. When data from days 200 through 420 of the study were used, none of the three loops exhibited a significant trend, indicating that levels had stabilized. No trends were detected in the copper level data, which were very erratic for the first half of the study period. During the secondhalf of the study period, copper levels exhibited anarrower range of values.

The similarity of lead and copper levels measured between each of the loops was evaluated using a Wilcoxonmatched pairs test. This test indicated that both lead and copper levels were similarinall three loops. This similarity can be seenin Figures 4.70 and 4.71, which display box and whiskers plots for both lead and copper levels


0.16

0.15

oo . 0.14

0.13CD

50. 0.12s

0.11

0.10.2 0.21 0.22 0.23 0.24 0.25 0.26 0.27

Copper levels (pipe rack), mg/L

0.15

0.145

0.14

6 0.135

0.13

0.125

0.12

a 0'" 5o.n

0.105

0.10.2 0.21 0.22 0.23 0.24 0.25 0.26 0.27

Copper levels (pipe rack), mg/L

Figure 4.64 Correlation of copper level measurements, Contra Costa Water District


Table 4.17a Summary of water quality data, Fort Worth lead-soldered copper loops

InfluentNumber of observationsAverage MinimumMaximumStandard deviation




Lead (mg/L)

600.0 00.0080.0

590.006 00.0180.01

580.006 00.0740.011

590.005 00.030.006

Copper Temperature Conductivity (mg/L) (°C) pH (umhos/cm)

590.0 00.090.0

590.551 0.0681.130.23

590.6 0.011.180.24

590.5 0.0671.160.23

29320.3

931

6.1

5925.9 1234

4.29

5925.9 1334

4.26

5926.0 1234

4.26

2928.1 7.78.70.2

598.1 7.88.60.19

598.1 7.78.60.19

598.1 7.98.70.20

293342.8 257477

31.9

59353.9 288560

44.06

59351.0 28747838.02

59351.1 288477

38.32

Alkalinity (mg CaCO/L)

293103.0 66

1289.1

59106.4 74

13311.53

59106.0

78139

12.15

59106.8

76143

12.55

Free chlorine (mg/L)

2930.0 00.40.0

590.0 000.00

590.0 000.00

590.0 000.00

from the Fort Worth Alta Mesa lead-soldered copperpipe loops. Lead levels in Loop 2 displayed a wider range of values than those in Loops 1 and 3, but overall the levels were similar. The ratio of the standard deviation to the mean for lead levels from all three loops was 1:1, and for copper levels 1:2.

Como Pump Station Lead Pipe Rack. The quality of the influent water is presented in Figures 4.72 through 4.74b. Alkalinity levels ranged from 86 to 180 mg/L CaCO3, withpH levels between7.4 and 8.4. The total chlorine residual entering the pipe rack varied from 0.7 to 4.3 mg/L, and dissolved oxygen was measured from 4.7 to 10.2 mg/L. Average standing lead levels from the three loops were 0.26,0.23, and 0.18 mg/L. Standing lead levels from all three loops are displayed inFigure 4.75. The distribution of the lead data was nonnormal. A slightly positive trend hi lead levels was detected in all three loops and the levels were somewhat erratic; i.e., the levels did not appear to stabilize during the study period.


Table 4.17b Summary of water quality data, Fort Worth lead-soldered copper loopsOrtho-

Total chlorine HPC Total Calcium Ammonia phosphate (mg/L) DO (cfu/mL) coliforms (mg/L) (mg/L) (mg/L)

InfluentNumber of observationsAverageMinimumMaximumStandard deviation

Loop 1Number of observationsAverageMinimumMaximumStandard deviation


LoopSNumber of observationsAverageMinimumMaximumStandard deviation

2932.30.73.70.6

590.503.10.83

590.5030.82

590.5030.83

638.10

11.61.4

597.85.8

10.50.98

597.86.19.90.93

597.95.9

10.70.98

85428.2

05,4001,169.2

593,422.2

05,4002,489.74

593,471.5

05,4002,425.23

593,334.8

05,4002,456.53

850.0000.0

590.0000.00

590.0000.0

590000.00

16114.9

015632.5

59119.9102140

10.61

59120.898

14411.52

59119.4102142

10.76

160.500.750.2

590.701.40.24

590.701.30.24

590.701.20.24

140.000.030.0

540.000.620.09

540.000.130.03

540.000.260.04

The similarity of lead levels measured in each of the loops was evaluated using a Wilcoxon matched pairs test. This test indicated that Loops 1 and 2 produced similar lead levels, but Loop 3 levels were significantly different (p level = .0003). The ratios of the standard deviation to the mean for lead levels from all three loops were as follows: Loop 1,1:3; Loop 2,1:5; Loop 3,1:2.

Operational ConsistencyThe Fort Worth Water Department operated the Alta Mesa and the Como

pipe racks for a total of 420 days, or 60 weeks, between September 4,1991, and October 28,1992. Both pipe racks were checked and sampled on a weekly basis.

Both racks experienced high HPC levels (>5,400) during the last half of the study period (see Figure 4.76). Increased water temperature and a change by the laboratory to a more sensitive medium for HPC analysis may have contributed to


Table 4.17c Summary of water quality data, Fort Worth lead-soldered copper loopsTotal phosphate

(mg/L)





150.000.150.0

550.000.650.11

550.101.70.23

550.000.270.06

Silicate (mg/L)

145.03.687.741.2

554.72.227.311.09

564.71.617.881.30

564.72.57.321.18

Iron (mg/L)

180.000.070.0

590.001.080.14

590.000.780.11

590.000.740.10

Zinc (mg/L)

180.000.20.0

590.001.850.24

590.000.210.03

590.000.190.03

Color (mg/L)

180.0000.0

590.0000.00

590.0000.00

590.0000.00

IDS (mg/L)

18218.2

0284

57.0

59238.2187377

31.40

59235.418732126.29

59235.619032026.15

these higher levels. No other major operational problems were noted except for inconsistent lead levels measured during the beginning of the study from the Como lead loops, which were attributed to the sample valves being opened too quickly, forcing fresh water into the loops under relatively high pressure. In early December 1991, operators were instructed to open the valves slowly during sample collection.

Distribution System Data EvaluationSummary Statistics, Lead-Soldered Copper Sites. Tap samples were

collected from 60 homes at approximately 4-week intervals from September 1991 through August 1992, for a total of nine sampling events. Two standing samples were collected: a250-mL sample followed by a750-mL sample. Samples were collected


Table 4.18a Summary of water quality data, Fort Worth lead loops______________Temper- Free Total

ature Conductivity Alkalinity Chlorine Chlorine(°C) pH (u mhos/cm) (mg CaCO/L) (mg/L) (mg/L)

Lead Copper (mg/L) (mg/L)

InfluentNumber of observations 55 56 293 293 292 292 293 293 Average 0.0 0.0 19.9 8.0 433.6 116.7 0.0 2.8 Minimum 0.00 0 8 7.4 255 86 0 0.7 Maximum 0.07 0.17 31 8.4 512 180 0.4 4.3 Standard deviation 0.01 0.04 6.58 0.17 37.88 12.99 0.02 0.64

Loop 1 Number of observations 59Average MinimumMaximumStandard deviation

0.0 00.150.03

Loop 2 Number of observations 59Average MinimumMaximumStandard deviation

Loops Numer of observationsAverage MinimumMaximumStandard deviation

0.0 00.120.02

590.0 00.250.04

597.9 49.61.09

598.0 5.49.70.88

597.8 4.99.80.95

5924.7 1532

4.07

5924.7 1432

4.16

5924.7 1232

4.22

598.0 7.68.50.17

598.0 7.68.50.16

598.0 7.68.40.17

59435.4 34349737.80

59430.2 327498

41.07

59430.7 327498

41.02

59114.8 89

14312.74

59114.5 88

14412.82

59115.1 89

14412.96

590.0 02.10.27

590.0 000.00

590.0 000.00

592.4 0.150.84

592.4 0.34.50.79

592.4 0.34.50.77

from homes built after January 1983 that contained copper piping joined with lead solder. The sampling dates and total number of houses where both 250- and 750-mL samples were collected and analyzed for lead and copper levels were as follows:

Sample period

123456789

Dates sampled

9/26/9111/7/9112/5/911/20/92-1/23/922/20/92-2/21/923/4/92-3/24/926/12/92-6/18/927/7/92-7/28/928/5/92-8/19/92

Number of houses211715223445384846

All data 286


Table 4.1 8b Summary of water quality data, Fort Worth lead loops




LoopSNumber of observationsAverageMinimumMaximumStandard deviation

DO (mg/L)

638.14.7

10.21.07

597.949.61.09

5985.49.70.88

597.84.99.80.95

HPC (cfu/mL)

81345.8

05,400

719.47

593,714.5

15,4002,357.72

593,713.2

05,4002,359.99

593,743.1

15,4002,269.93

Total coliforms

810.0000.00

590.0000.00

590.0000.00

590.0000.00

Calcium (mg/L)

15119.886

13812.52

59123.190

16015.72

59122.890

16216.44

59122.790

16215.53

Ammonia (mg/L)

150.60.360.910.11

580.70.27.50.91

580.70.217.60.93

580.70.177.70.94

Ortho- phosphate

(mg/L)

140.000.050.01

550.000.60.12

550.000.090.02

550.000.540.08

Total phosphate

(mgVL)

150.000.220.06

490.100.590.12

540.000.540.09

540.000.280.05

OPO = orthophosphate TPO4 = total phosphate

The lead and copper levels measured from these samples are provided in Appendix G. Lead levels from the 250-mL samples ranged from 0.003 to 0.023 mg/L with an average of 0.0045 mg/L. Lead levels from the 750-mL samples ranged from 0.001 to 0.073 mg/L, with an average of 0.0041 mg/L. Only two of the 250-mL samples and three of the 750-mL samples had lead levels higher than the regulatory action level of .015 mg/L. Copper levels were essentially the same for both the 250- and 750-mL standing samples collected at the tap, with average concentrations of 0.51 and 0.53 mg/L, respectively. None of the samples had levels greater than the regulatory action level of 1.3 mg/L.

Lead and copper results from the 250- and the 750-mL samples were also combined to obtain calculated 1,000-mL levels for these metals. These calculated results were compared to the action levels specified in the final Lead and CopperRule.


Table 4.18c Summary of water quality data, Fort Worth lead loops




LoopsNumber of observationsAverageMinimumMaximumStandard deviation

Silicate (mg/L)

145.42.267.821.45

515.72.348.181.29

565.92.288.961.27

565.62.727.821.26

Iron (mg/L)

170.000.40.10

540.000.880.14

590.000.630.12

590.000.80.13

Zinc (mg/L)

170.000.120.03

540.001.910.26

590.000.590.09

590.000.20.04

Color

170.0000.00

540.0000.00

590.0000.00

590.0000.00

IDS (mg/L)

17284.224232926.85

54293.323034425.56

59288.522033827.62

59288.422033727.75

On the basis of calculated 1,000-mL lead and copper levels, the 90th percentile levels for these metals were as follows:

Calculated 1,000-mL sample 90th percentile levels

Sample period

123456789

All of the 90th percentile lead or copper levels were below the action levels specified in the final Lead and Copper Rule.

Lead (mg/L)

0.00950.01350.00680.00650.00980.00680.00430.00400.0035

Copper (mg/L)

0.910.680.750.390.980.750.930.770.72


9.0 8.9 8.8 8.7 8.6 8.5 8.4 8.3 8.2

a s-itt 8.0

7.9 7.8 7.7 7.6 7.5 7.4 7.3 7.2 7.1 7.0

07/31/91 11/08/91 02/16/92 05/26/92 09/03/92

Date

12/12/92

Figure 4.65a Influent pH levels, Fort Worth Alta Mesa pipe rack

140

130

120

8 nots U

_e

I 90

80

70

6007/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

Date

Figure 4.65b Influent alkalinity levels, Fort Worth Alta Mesa pipe rack


500

480

460

440

420

400

380

360

340K

U 320

300

280

260

240

T3

07/31/91 11/08/91 02/16/92 05/26/92Date

09/03/92 12/12/92

Figure 4.66a Influent conductivity, Fort Worth Alta Mesa pipe rack

34

32

30

28

26•".24

a1 22 a, I 20H

18 -

16 -

14

12 -

10 -

807/31/91 11/08/91 02/16/92 05/26/92

Date09/03/92 12/12/92

Figure 4.66b Influent temperature levels, Fort Worth Alta Mesa pipe rack


4.0

3.8

3.6

3.4 3.2

2.81" 2'61 2.44>S 2.2 hc'§ 2.0 -

"S 1.8-ao 1.6 h

1.4 h 1.2 1.0 0.8 0.6

07/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92Date

Figure 4.67 Influent total chlorine residual, Fort Worth Alta Mesa pipe rack


• Loop 1+ Loop 2O Loop 3

0 40 80 120 160 200 240 280 320

0.01 -

1.3

1.2

1.1

1

0.9

0.8

0.7°-60.5

0.4

0.3

0.2

0.1

00 40 80 120 160 200 240 280 320

Day

Figure 4.68 Standing lead and copper levels, Fort Worth Alta Mesa pipe rack


Loop 1

I

0.02

0.015

0.01

0.005

CO

T3

0.04

0.03

0.02

0.01

-0.01

100 200 300Day

0.090.080.07

^0.06

400

Loop 2

0.04o-030.020.01

0-0.01 100 200 300

Day400

Loop 3

0 100 200Day

300 400

Figure 4.69 Estimated trend lines for lead levels, Fort Worth Alta Mesa pipe rack, all data

0.05

0.04

0.03

I 0.02

0

-0.01

-0.02


an • Mean

en 2 Standard Error


Loop 1 Loop 2 Loop 3

Figure 4.70 Box and whiskers plot of lead levels, Fort Worth Alta Mesa lead-soldered copper loops

l.J 1.21.1

1

lib 0.8

> U.o •5 0.5u & 0.4Q 0.3

0.20.1

0-0.1 no

.•

~~

1 1 1 1 I

— - _

.•

-

1 ^Mean

a 2 Standard Error


Loop 1 Loop 2 Loop 3Figure 4.71 Box and whiskers plot of copper levels, Fort Worth Alta Mesa lead-soldered copper loops


98.98.8

8.7

8.68.58.48.38.28.1

8

7.97.87.77.67.57.47.37.27.1

707/31/91 11/08/91 02/16/92 05/26/92 09/03/92

Date

Figure 4.72a Influent pH levels, Fort Worth Como pipe rack

12/12/92

190

180

170

160

8" 15°U 140

%130

110

100

90

8007/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

Date

Figure 4.72b Influent alkalinity levels, Fort Worth Como pipe rack


540

520

500

480

460

I 440"3

| 420

I 400

•I 380

1 360

5 340

320

300

280

260

24007/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

Date

Figure 4.73a Influent conductivity, Fort Worth Como pipe rack

u

07/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

DateFigure 4.73b Influent temperature, Fort Worth Como pipe rack


4.5

3.5

I

9Ju 2.5c 'C

1.5

1 -

0.507/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

Date

Figure 4.74a Influent total chlorine, Fort Worth Como pipe rack

11

10

8u

Xo•o 7 u '

gWS

5

I_____I_____I

07/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

DateFigure 4.74b Influent dissolved oxygen, Fort Worth Como pipe rack


320

Figure 4.75 Standing lead levels, Fort Worth Como pipe rack

3

a"B,u

12 2

1 o

0• •l

07/31/91 11/08/91 02/16/92 05/26/92 09/03/92 12/12/92

Date

Figure 4.76 Influent hetrotrophic plate count, Fort Worth Como pipe rack


To compare the home tap sample data with lead and copper levels measured from the pipe rack, the pipe rack data were divided into nine sample periods that coincided with the nine sampling events in the distribution system. Pipe rack data were collected weekly for approximately 60 weeks from three replicate test loops. Previous evaluation of the pipe rack data indicated that all three replicate loops producedmetals levels that were statistically the same. Therefore, the comparison of pipe rack data to distribution system tap data was completed using data from all three loops. Results from the pipe rack were grouped into nine sample periods based on the proximity of the sampling event to the distribution system sample period. The number of lead and copper samples from the pipe rack for each of the sample periods was as follows:

Number ofSample Pipe rack lead and period study period (date) copper samples

1 9/4/91-10/9/91 182 10/16/91-11/20/91 173 11/27/91-12/31/91 14 lead, 15 copper4 1/8/92-2/5/92 155 2/12/92-2/26/92 96 3/4/92-3/25/92 127 6/3/92-6/24/92 128 7/2/92-7/31/92 159 8/7/92-8/27/92 12

All data 124,125

A comparison of the means, medians, and standard deviations for lead and copper levels from both Ihe tap samples and the pipe rack samples is displayed in Table 4.19. The average and median lead levels measured from the pipe rack were generally higherthan those of the distribution system samples, with the exception of sample periods 6 and 7. Copper levels from the pipe rack fell within the same range as levels measured in the distribution system. Figures 4.77 and 4.78 display the average and median lead and copper levels from the distribution system and pipe rack. The standard deviations for all standing lead and copper levels measured from the distribution system and from the pipe rack are shown in Figures 4.79 and 4.80. Lead levels from the 750-mL standing samples exhibited more variation than did the 250-mL samples during the first two sample periods, after which they were very similar. The pipe rack exhibited high variation during sample periods 5, 8, and 9. During sample periods 6 and 7, the range of values measured in the pipe rack was actually lower than the values measured in the distribution system. The variation in copper levels was similar for the 250-mL, 750-mL, and pipe rack samples. The variation in lead and copper levels can also be evaluated based on the coefficient of variation (i.e., the ratioofthe standard deviationdividedbythemean).Thelowerthe ratio, the more variability observed in the data. Table 4.20 contains a summary of the ratios of the standard deviation to the mean for mean lead and copper levels. The ratios for lead levels from the pipe rack ranged from 1:1 to 1:7, and for calculated


Table 4.19 Summary statistics for lead and copper levels for pipe rack and distribution system tap samples, Fort Worth Water Department, lead-soldered copper sites

Sample Pipe period rack

Average level

Tapsampli

Standard deviation

38 Tap samples

Calculated 250 mL 750 mL 1,000 mL

PipeftU^ftown 250 ml 750 ml

Calculated Pipe 1,000 ml rack

Median level

Tap samples

250 mLCalculated

750 mL 1,OOOmL

Lead123456789

0.0090.0100.0060.0060.0210.0020.0020.0040.008

0.008 0.0090.005 0.0060.005 0.0040.005 0.0040.007 0.0060.006 0.0040.003 0.0030.003 0.0030.002 0.003

0.0080.0060.0040.0040.0060.0050.0030.0030.003

0.0040.0010.0030.0030.0210.0000.0000.0040.011

0.0050.0020.0030.0030.0030.0030.0020.0010.001

0.0150.0090.0020.0020.0030.0020.0010.0010.001

0.0110.0070.0020.0020.0030.0020.0010.0010.001

0.0780.0090.0060.0050.0140.0020.0020.0030.002

0.0070.0040.0040.0050.0070.0060.0020.0030.002

0.0040.0040.0030.0040.0050.0040.0020.0030.002

0.0050.0050.0040.0040.0060.0050.0020.0030.002

Copper123456789

0.630.470.460.280.620.460.620.540.56

0.26 0.520.69 0.550.63 0.490.30 0.270.55 0.590.65 0.460.58 0.570.63 0.520.71 0.53

0.670.450.460.280.620.460.630.550.57

0.240.280.240.100.220.330.060.080.10

0.310.190.200.110.260.190.180.160.14

0.280.230.220.120.280.200.200.150.14

0.270.200.200.110.270.200.190.150.14

0.170.640.720.340.460.540.590.650.70

0.500.560.480.270.600.420.560.530.51

0.700.490.460.300.630.420.640.550.58

0.670.490.470.270.610.420.610.540.56

1,000-mL samples the ratios ranged from 1:1 to 1:3. Pipe rack copperdataexhibited ratios ranging from 1:1 to 1:9, whereas the tap sample ratios were consistent between 1:2 and 1:4.

Frequency distributions for lead and copper levels were calculated to evaluate whether these sample groups represented normal or nonnormal distributions. The lead levelsmeasuredfrom standing tap samples displayed nonnormal distributions, as seen in the frequency distribution curve for calculated 1,000-mL samples inFigure 4.81. Copper levels were much closerto anormal distribution (Figure 4.81). The lead and copper level distribution for pipe rack data can be seen in Figure 4.82. The distribution of these data is similar to that of the tap samples.

Statistical Difference in Metals Levels, Lead-SolderedCopper Sites. To determine if the mean or median lead and copper levels measured at the tap were statistically different from those of the pipe rack samples, a nonparametric Wilcoxon matched pairs test was performed using the average and median lead and copper levels for all nine sample periods. Because the lead level data from the pipe rack approached stabilization after day 200 (after sample period 6), the comparison of values was also made using values from sample periods 7 through 9.

0.023 r-0.022 -0.021 -0.02 -

0.019 -0.018 -0.017 -3 °-° 16 -

"33 0.015 -j> 0.014 -•g 0.013 -£ 0.012 -§0 0.011 -

§ 0.01 -<; 0.009 -

0.008 -0.007 -0.006 -0.005 -0.004 -0.003 -0.002 L

Average

0.09

0.08

0.07

°'06

I" 0.05JU

1 0.04

0.03<D

S

0.02

0.01

A Rack + 750 mLo Calculated 1,000 mL • 250 mL

4 5 Sample period

Median

A Rack+ 750 mLo Calculated 1,000 mL• 250 mL

Sample periodFigure 4.77 Average and median lead levels from Alta Mesa pipe rack and lead-soldered copper distribution system sites

0.8

0.7

0.6

JS °'5"53

I"5 a 0.4o U

0.3

0.2

Average

<u

a

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.11


456 Sample period

Median

8


8234567

Sample periodFigure 4.78 Average and median copper levels from Alta Mesa pipe rack and lead-soldered copper distribution system sites

U.US

0.070.06

1b °-05S 0.044 0-03j> 0.02Ti o.oi•J 0

-0.01-0.02_nm

- •L :: 250-mL samples '.i- -J

- -

i. -; D[i **<r'i'****::

- -I

|Mean

en 2 StandardError


345 Sample period

u.uo0.070.06

0.050.040.030.020.01

0-0.01-0.02_nm

•-•-•.

; E--

-750-mL samples -j

----

JM *•£'£****].12 345

Sample period

| Mean



u.uo

0.070.06

^ 0.05 |> 0.04« 0.03<uS 0.02

1J 0

-0.01-0.02

iT T

i T 'r1 41 1 X T--

Pipe rack samples

r,Xj M

* "*" X

--•

r.

i

.-

|Mean

c=i 2 StandardError


12 3456789 Sample period

Figure 4.79 Box and whiskers plots of lead levels, Fort Worth lead-soldered copper tap samples and Alta Mesa pipe rack

l.O

1.41.2

f. 0.8| 0.6

<Uu 0.4u a, Q 2& >ZU 0

-0.2-0.4-0.6 ——— —————————————

_-.: E•

1 ^ i] d M

Q

.•

[i

0

250-mL samples

ilJ r*\t

r " T T, 00 QO [1]

TiHMean

a 2 StandardError



1.61.41.2

rf °' 81 0.6_ub °-4| 0.2

0-0.2-0.4

--

: E-•

iJ ri 1 ' 1 -, 1

[j

j. -*• ~-

-

i

i]

750-mL samples

i•^ r-

[l

T ^r T •L| j .- -. n n

i]

- • -1- j

I Mean

a 2 StandardError



1.61.41.2

S. 0.8Crt

f 0.6<ub 0.4Q,& 0.2U

0-0.2n /i

--

-

[_--

i

]

.p

J F J

[j

i

i]n t

Pipe rack samples

j] * * T ; • Mean

<=i 2 StandardError


1 8234567 Sample period

Figure 4.80 Box and whiskers plots of copper levels, Fort Worth lead-soldered copper tap samples and Alta Mesa pipe rack


Table 4.20 Ratios of standard deviation to mean for average lead and copper levels, Fort Worth Water Department, lead-soldered copper sites

Lead Copper

Tap samples

Evaluation period

123456789

Pipe rack

1:21:71:21:21:10:11:71:11:08

250 mL

1:11:21:11:11:21:21:11:21:2

750 mL

1:.061:.071:21:11:11:21:21:21:3

Calculated 1,000 mL

1:.081:21:21:21:11:21:21:21:3

Pipe rack

1:11:21:21:31:21:21:91:71:7

250 mL

1:11:31:21:21:21:21:31:31:3

Tap samples

750 mL

1:21:21:21:21:21:21:31:31:4

Calculated 1,000 mL

1:21:21:21:21:21:21:31:31:4

Mean and median lead levels from the pipe rack were both found to be significantly different from the 250-mL, 750-mL, and calculated 1,000-mL tap lead levels at the .10 p level. When data from sample periods 7 through 9 were used, however, the lead level results were statistically similar. Pipe rack copper levels were statistically the same as distribution system tap samples. The significance levels were as follows:

Wilcoxonp levels mean lead levels



Wilcoxonp levels mean copper levels sample periods 1-9

Pipe rack versus 250 mL .21Pipe rack versus 750 mL . 31Pipe rack versus 1,000 mL .31

In summary, the copper levels measured from the pipe rack were essentially the same as the levels measured in standing samples at the tap. Lead levels measured in the pipe rack after stabilization were also similar to tap lead levels.

Correlation of Lead and Copper Levels, Lead-Soldered Copper Sites. Lead and copper levels from the pipe rack were also evaluated to determine if they correlated to standing tap levels. The results of this evaluation are reported as a correlation coefficient, or rvalue. The correlation of the lead levels from the pipe rack


Lead

8— Expected

s s0~0

Category (upper limits)

Copper

— Expected


L^S^y distribution for lead and ^PPer "evels, Fort Worth lead-soldered distribution system sites, calculated 1,000-mL samples


Lead

— Expected


Copper

— Expected

Category (upper limits)Figure 4.82 Frequency distribution for lead and copper levels, Fort Worth Alta Mesa pipe rack

to lead levels from the standing tap samples was completed using average and median lead levels from sample periods 7 through 9. This was the period during the study when the lead levels had stabilized in the pipe rack. The Spearman rvalues computed for the correlation of average lead levels from the pipe rack to the tap samples for sample periods 7 through 9 were as follows:


Spearman r value p levelPipe rack versus 250 mL -1.0 (+.3) —Pipe rack versus 750 mL -.6 (+.3) .4 (.7)Pipe rack versus 1,000 mL -.8 (+.3) .2 (.7)

Correlations and p levels from median lead levels are given in parentheses. The results indicate that there is no correlation between lead levels hi the pipe rack and lead levels from the 250-mL tap samples, and the correlation is not significant for either the average or median levels from the 750-mL and 1,000-mL tap samples. When lead levels from the individual houses were correlated to pipe rack lead levels, only three houses displayed a significant correlation (p level < .05, Spearman r = .75-.90). Copper level correlations were calculated using data from the entire study period. The results were as follows:


Spearman r value p levelPipe rack versus 250 mL +. 15 (+. 12) .7 (.8)Pipe rack versus 750 mL -.3 (-.2) .4 (.6)Pipe rack versus 1,000 mL -.3 (-.2) .5 (.6)

As with the lead levels, these correlations are not significant. Only one house displayed a significant correlation (p level < .05) with respect to copper levels. In summary, when comparing the lead and copper levels measured from the pipe rack to lead and copper levels measured from standing tap samples, there is essentially no correlationin actual levels. However, the range of levels measured and the variability hi the data were similar between the pipe rack and the home tap samples.

Summary Statistics, Lead Service Sites. Home tap samples were collected at 88 differenthomes at approximately 4-week intervals from October 1991 through August 1992. Samples were collected from homes that contained lead service lines or lead gooseneck connections. Three samples were collected: a standing 1,000-mL sample, a 1,000-mL sample drawn afterthe water was allowed to flush for 1 minute, and a 1,000-mL sample collected after a 2-minute flush. This timed-interval flushing was chosen as a best estimate of the flushing time required to obtain water in contact with the lead service lines (1 -minute flush). Actual calculation of the required flushing time for each house was not completed because of staffing constraints. The total number of houses where samples were collected and analyzed for lead during each sampling period was as follows:


Sample Dates Number of period sampled houses

1 10/3/91-10/17/91 422 11/21/91 273 12/12/91-12/19/91 424 1/12/92-1/30/92 165 2/6/92-2/27/92 266 3/3/92-3/24/92 527 6/9/92-6/30/92 888 7/7/92-7/28/92 389 8/18/92-8/28/92 43

All data 374

The lead levels measured from these samples are listed in Appendix G. Lead levels from the first standing sample collected at the tap ranged from 0.001 to 0.092 mg/L, with an average of 0.009 mg/L. Lead levels from the second sample had a smaller range of values, from 0.001 to 0.048 mg/L, but the average was the same. The average lead level from the third sample was much lower, 0.005 mg/L, with a range of 0.001 to 0.052 mg/L. Lead levels in the first sample may be attributable to the faucet and/or the presence of lead solder hi the home plumbing. Lead concentrations in the second sample are more likely the result of contact with the service connection.

Twelve percent of the first sample, 14 percent of the second, and 5 percent of the third had lead levels higher than the regulatory action levels of 0.015 mg/L. The 90th percentile lead levels, in mg/L, are summarized below.

90th percentile level lead levels (mg/L) j

Sample periodSample

10.0340.0220.0160.0170.0180.0130.0140.0150.015

Sample2

0.0280.0190.0140.0110.0160.0140.0150.0190.019

Sample3

0.0270.0120.0140.0100.0110.0100.0070.0080.006

123456789

Five of the sample periods for the first and second samples had 90th percentile lead levels above the action levels specified in the final Lead and Copper Rule. For the third sample, only sample period 1 had a 90th percentile lead level exceeding the 0.015-mg/L limit.

To compare the home tap sample data with lead levels measured from the pipe rack, the pipe rack data were divided into nine sample periods that coincided with the nine sampling events hi the distribution system. Pipe rack data were collected weekly for approximately 60 weeks from three replicate test loops. Previous


evaluation of the pipe rack data indicated that two of the three replicate loops (Loops 1 and 2) produced, metals levels that were statistically the same. Therefore, the comparison of pipe rack data to distribution system tap data was completed using data from Loops 1 and 2. Results from the pipe rack were grouped into nine sample periods based on the proximity of the sampling to the distribution system sample period. The number of lead samples from the pipe rack foreach of the sample periods was as follows:

Sample period

123456789

Pipe rack study periods (dates)

10/2/91-10/30/9111/6/91-11/27/9112/4/91-12/31/911/8/92-1/29/922/5/92-2/26/923/4/92-3/25/926/3/92-6/24/927/2/92-7/31/928/7/92-8/27/92

All data

Number of lead samples

108

108888

108

78

A comparison of the means, medians, and standard deviations for lead levels from both the tap samples and the pipe rack samples is displayed in Table 4.21. The average and median lead levels measured from the pipe rack were much higher than those of the distribution system samples, as seen in Figure 4.83. The standard deviations for all standing lead levels in the distribution system and from the pipe rack are shown in Figure 4.84. The second standing sample exhibited the most variation in lead levels measured from tap samples. The pipe rack exhibited a wide range of lead

Table 4.21 Summary statistics for lead levels for pipe rack and distribution system tap samples, Fort Worth Water Department, lead service sites

Average levels

Tap samples

Sampleperiod

123456789

Piperack

0.1760.1420.1330.2020.2220.2860.2530.2360.390

No 1-minuteflush

0.0150.0070.0080.0060.0090.0090.0080.0090.011

flush

0.0110.0060.0070.0040.0090.0080.0080.0100.015

2-minuteflush

0.0110.0060.0060.0040.0060.0050.0040.0040.004

Piperack

0.0440.1580.1000.2030.2350.2820.2090.2010.396

Standard deviation

Tap samples

Noflush

0.0100.0030.0070.0030.0070.0080.0070.0080.011

1-mlnuteflush

0.0070.0040.0060.0030.0080.0080.0080.0090.014

2-mlnuteflush

0.0080.0020.0040.0030.0050.0040.0040.0040.004

Piperack

0.2280.0480.1080.0690.0780.0460.0990.0860.145

Median levels

Tap samples

Noflush

0.0170.0090.0060.0050.0050.0040.0050.0050.005

1-mlnute 2-mlnuteflush

0.0110.0060.0050.0040.0040.0040.0050.0050.007

flush

0.0110.0070.0050.0030.0040.0030.0030.0030.002

0.45

0.4

0.35

0.3S4 0.25 z i 0.2

0.15

0.1

0.05

0

Average

0.45

0.4

0.35

| 0.25<L> 0.2

0.15

0.1

0.05

0

• No flush+ 1-minute flusho 2-minute flusha Rack

456 Sample period

Median

• No flush+ 1-minute flush* 2-minute flushA Rack

456 Sample period

Figure 4.83 Average and median lead levels from Como pipe rack and lead service distribution system sites


u.o 0.7 0.6

1b °'5S 0.4

JS 0-3's °-2"S o•2 -o.i

-0.2 -0.3 -0.4

0.8 0.70.6 0.5

lib 0.4S. 0.3| 0.2J3 0.11 o•J -0.1

-0.2 -0.3 -0.4

0.8 0.7 0.6

^ 0.4£. 0.3to

13 0.2 J2 0.1"8 0u J -0.1

-0.2-0.3 n /i

L First 1,000-mL sample j

\[••

^ ^

.

]

?••••»*• -t*• H•- ^- -•»- -4

2 3 4 5 6 7 J

•- -4

•i•i•i•:

,. j

.

|Mean

CD 2 StandardError


5 9

I Second 1,000-mL sample

HMean

en 2 StandardError


123456789

\

-

\

-

Pipe rack samples

1 [ ] E i] t i ^ E-

J [

_

ii

•i :-i



Figure 4.84 Box and whiskers plots of lead levels, Fort Worth lead service sites and Como pipe rack

values, particularly during sample periods 1 and 9. The ratios of the standard deviation divided by the mean (coefficient of variation) for the distribution system samples were actually lower than those for the pipe rack, however (Table 4.22), indicatinghighervariability. The coefficients of variation for lead levels from the pipe rackranged from 1:1 to 1:6, andforthe tap samples from 1:1 to 1:2. The higher overall lead levels measured from the pipe rack as compared to those from the tap samples caused the variabilities to be lower in lead levels from the pipe rack.

Frequency distributions for lead levels were calculated to evaluate whether these sample groups represented normal or nonnormal distributions. The lead levels measured from standing tap samples displayed nonnormal distributions, as seen in the frequency distribution curves for the three 1,000-mL samples collected at the tap (Figure4.85). The lead level distribution for pipe rack data can be seeninFigure4.86. These data, although also nonnormal, more closely approximate anormal distribution.

StatisticalDifference in Metals Levels, Lead Service Sites. To determine if the mean ormedian lead levels measured at the tap were statistically different from those of the pipe rack samples, a nonparametric Wilcoxon matched pairs test was performed using the average andmedian lead levels for all nine sample periods. Mean and median lead levels from the pipe rack were both found to be significantly different from all three samples collected at the tap (p level < .01).

Correlation of Lead and Copper Levels, Lead Service Sites. Lead and copper levels from the pipe rack were also evaluated to determine if they correlated to standing tap levels. The results of this evaluation are reported as a correlation coefficient, or r value. The correlation of the lead levels from the pipe rack to lead levels from the standing tap samples was completed using average and median lead levels from sample periods 1 through 9. The Spearman r values computed for the correlation of average lead levels from the pipe rack to those of the tap samples were as follows:

Table 4.22 Ratios of standard deviation to mean for average lead levels, Fort Worth Water Department, lead service sites

Sample period

123456789

Rack

1:0.81:31:11:31:21:61:21:21:2

250 mL

1:11:0.81:11:11:11:21:11:21:2

750 ml

1:11:11:11:11:21:21:11:21:2

1,000 mL

1:11:0.81:11:11:11:11:11:11:2

Sample 1 - First 1,000 mL No flush

!O;z! v">C3 l<">cniO'<frgq^qyocoo §o§oqdOd

<0 V> IO^ O V-,q d q

8 S o «< _ - _- o q d qo o o o


£; i/i oo ir>O t> O <x> g f> '—I <O ^H IT)

^ O O r-1 ^1

^ d q ° "i d -:o o o d

— Expected

160

140

120

>, 100

8 803

1? 60

40

200

Sample 2 - Second 1,000 mL 1-minute flush

p d

W")i—I

q dS en mO en

cS O Sd

Category (upper limits)id

— Expected

qd

Sample 3 - Third 1,000 mL 2-minute flush

eno•o8d

— Expected


Figure 4.85 Frequency distribution for lead levels, Fort Worth lead service sites


0.3 0.4 0. Category (upper limits)

Figure 4.86 Frequency distribution for lead levels, Fort Worth Como pipe rack

— Expected

0.02

0.015

•3 0.01

•§_ 0.005

3

-0.005

-0.010 0.05 ai 0.15 °'2 0.25 °' 3 0.35 °'4 0.45 °'5

Como pipe rack lead levels, mg/L

Figure 4.87 Correlation of median lead levels, lead service sample 2 and Como pipe rack

Discussion and Analy,

Lead level correlate sample periods 1-9

Spearman r value p HJ

Pipe rack versus first sample(no flush) +.32 (+.20) .4 (J6)

Pipe rack versus second sample(1-minuteflush) +.50 (+.60) .2 (.09))

Pipe rack versus third sample(2-minute flush) -.56 (+.13) .12 ^

Correlations and p levels for median lead levels are given in parentheses. The results indicate that the most significant correlationisbetweenmedianlead levels in the pipe rack and median lead levels from the second sample collected at the tap. This correlationis significant at the .09plevel. This correlation is presented inFigure4.87. When second-sample lead levels from the individual houses were evaluated, five houses exhibited a significant correlation (p < .05) to lead levels from the pipe rack (Spearman r = .7-.8).

Portland Water BureauPipe Rack Water Quality Data Summary and Statistical Evaluation

The Portland Water Bureau constructed and operated an AWWARF pipe rack containing three replicate copper loops soldered with 50:50 lead-tin solder. A summary of the water quality data collected from each of the replicate loops as well as from the influent running water is shown in Tables 4.23a and 4.23b. A complete set of the data is included in Appendix G. The influent water exhibited a relatively narrow range of water quality characteristics throughout the study period. Alkalinity levels ranged ffom4.3 to 12mg/L as CaCO3,withpH levels between 6.5 and7.2.The total chlorine residual entering the pipe rack ranged from 0.6 to 1.4 mg/L C12, and the dissolved oxygen varied from 8.1 to 13.6 mg/L. Figures 4.88 through 4.90 display the incoming water quality characteristics for several parameters as measured throughout the study period.

Average standing lead levels measured from the three replicate loops were 62, 77, and 49 ug/L, respectively, with maximum values of 260, 420, and 330 ug/L. Average standing copper levels were 1.3 mg/L for all three loops, with maximum values of 3.6,4.1, and 2.1 mg/L. Standing lead and copper levels measured throughout the study are displayed in Figure 4.91.

Lead levels displayed a definite downward trend until the end of September 1991, or approximately 78 days into the pipe rack operation, after which the levels appeared to stabilize. Copper levels also appeared to stabilize after this date. Occasional high lead and copper levels were measured at various times throughout the study period, however. Estimated trend lines for lead and copper levels from each of the three loops are displayed in Figures 4.92 and 4.93. A significant decreasing

Tabl

e 4.

23a

Sum

mar

y of

wat

er q

ualit

y da

ta, P

ortla

nd W

ater

Bur

eau,

AW

WAR

F pi

pe ra

ck

Tem

pera

ture

(°C

)

Influ

ent

Num

ber o

f ob

serv

atio

nsAv

erag

eM

inim

umM

axim

umSt

anda

rd d

evia

tion

Loop

AN

umbe

r of

obs

erva

tions

Aver

age

Min

imum

Max

imum

Stan

dard

dev

iatio

nLo

op B

Num

ber o

f obs

erva

tions

Aver

age

Min

imum

Max

imum

Stan

dard

dev

iatio

nLo

op C

Num

ber

of o

bser

vatio

nsAv

erag

eM

inim

umM

axim

umSt

anda

rd d

evia

tion

52.0

13.4 8.0

18.5 4.1

52 21.2

11 32 5.43

52 21.2

11 32 5.4

52 21.1

7311 32

.5 5.43

Fiel

d C

ondu

ctiv

ity

pH

(um

hos/

cm)

51.0 6.9

6,5

7.2

1.8

52 6.7

6.33

7.1

0.17

52 6.7

6.4

7.2

0.17

52 6.74

76.

357.

20.

17

51.0

24.7

20.0

40.0 9.08

52 31.2

20 50 6.09

52 31.0

20 40 5.64

52 30.7

6920 40 5.

83

Tota

l ch

lorin

e (m

g/L)

51.0 0.9

0.6

1.4

0.24

52 0.2

0.1

0.4

0.07

52 0.2

0.1

0.3

0.06

52 0.16

00.

10.

40.

07

Free

ch

lorin

e (m

g/L)

51.0 0.3

0.1

0.8

0.16

52 0.1

0.1

0.1

0.00

52 0.1

0.1

0.1

0.00

52 0.10

00.

10.

10.

00

DO

(m

g/L)

39.0

10.6 8.1

13.6 4.97

43 6.4

2 9.1

1.81

4

43 6.4

2 9.8

1.84

45 6.13

60 10

.1 2.26

Lab

PH 45.0 6.9

6.6

7.2

0.14

46 6.8

6.5

7.1

0.14

46 6.9

6.5

7.1

0.13

46 6.92

26.

67.

10.

13

Col

or

(cu)

46.0 5.0

5.0

5.0

0.00

0

46 5.0

5 5 0.00

46 6.52

5.00

70 9.49

46 5.97

85 40 5.

28

Dis

solv

ed

Orth

o-

solid

s ph

osph

ate

(mg/

L)

(mg/

L)

10.0

25.0

21.0

30.0

10.8

10 26.2

22 31 2.89

10 26.6

22 31 3.07

10 26.9

0023 31 2.

84

10.0 0.00

30.

003

0.00

50.

001

10 0.00

30.

003

0.00

30.

000

10 0.00

30.

003

0.00

70.

001

10 0.00

30.

003

0.00

60.

001

Tabl

e 4.

23b

Sum

mar

y of

wat

er q

ualit

y da

ta, P

ortla

nd W

ater

Bur

eau,

pip

e ra

ck

Influ

ent

Num

ber o

f obs

erva

tions

Aver

age

Min

imum

Max

imum

Stan

dard

dev

iatio

nLo

op A

Nu

mbe

r of o

bser

vatio

nsAv

erag

e M

inim

umM

axim

umSt

anda

rd d

eviat

ion

Loop

B

Num

ber

of o

bser

vatio

nsAv

erag

e M

inim

umM

axim

umSt

anda

rd d

eviat

ion

Loop

C

Num

ber o

f obs

erva

tions

Aver

age

Min

imum

Max

imum

Stan

dard

dev

iatio

n

Tota

l ph

osph

ate

(mg/

L)

10.0 0.00

5 0.

005

0.00

70.

002

10 0.00

5 0.

005

0.00

50.

000

10 0.00

6 0.

005

0.01

10.

002

10 0.00

6 0.

005

0.00

90.

001

Alka

linity

(m

g Ca

COj/L

)

46.0 7.3

4.3

12.0

341 46 9.

3 6.

114 2.

3

46 9.3

5.4

15 2.37

46 9.37

8 6.

114 2.

25

Silic

a (m

g/L)

10.0 4.41

0 3.

800

5.40

00.

54

10 4.4

3.8

5.3

0.50

10 4.4

3.8

5.3

0.49

10 4.39

0 3.

85.

30.

5

Copp

er

(mg/

L)

51.0 0.01

2 0.

010

0.03

00.

005

52 1.3

0.56

3.6

0.45

52 1.29

0.

824.

10.

49

52 1.28

2 0.

842.

10.

34

Calc

ium

(m

g/L)

13.0 2.10

0 1.

600

2.90

00.

419

13 2.3

1.8

3 0.38

13 2.3

1.8

3 0.36

13 2.40

0 1.

83.

40.

44

Lead

(m

g/L)

52.0 0.00

2 0.

001

0.02

20.

003

52 0.06

2 0.

010.

260

0.04

2

52 0.07

7 0.

008

0.42

0.08

6

52 0.04

9 0.

008

0.33

00.

07

Zinc

(m

g/L)

13.0 0.01

1 0.

010

0.01

90.

002

13 0.01

0 0.

010.

012

0.00

1

13 0.01

0 0.

010

0.01

10.

000

13 0.01

2 0.

010.

038

0.00

7

Iron

(mg/

L)

13.0 0.08

7 0.

024

0.23

00.

06

13 0.1

0.02

30.

170.

04

13 0.2

0.01

1.3

0.34

13 0.12

5 0.

031

0.54

0.15

Amm

onia

(m

g/L)

10 0.1

0.06

30.

220.

052

10 0.2

0.13

0.33

0.07

13 0.15

9 0.

000

0.32

0.10

10 0.21

8 0.

140.

330.

07

1 §' fr 50 i to


1211

J 10en8 9

U 8

£ 7

I!3210 7/7/91 I" 10/15/91" I 1/23/92 I 5/2/92 ~ I 8/10/92

8/26/91 12/4/91 3/13/92 6/21/92

Date

8

7

6

5

a 4Cu

0 7/7/91 I 10/15/91 1/23/92 ~ I 5/2/92 8/10/92 8/26/91 12/4/91 3/13/92 6/21/92

Date Figure 4.88 Influent pH and alkalinity levels, Portland Water Bureau

1.5 1.4 1.3 1.2 1.1

10.9 0.8

0.5 0.4 0.3 0.2 0.1

07/7/91 I 10/15/91 * 1/23/92 ~ I 5/2/92 ' 8/10/92

8/26/91 12/4/91 3/13/92 6/21/92

Date

15141312

S 10c 9<u(JA O

^

1 61 55 4

3210

7/7/91 ' 10/15/91 ' 1/23/92 ' 5/2/92 ' 8/10/92 8/26/91 12/4/91 3/13/92 6/21/92

Date Figure 4.89 Influent total chlorine and dissolved oxygen levels, Portland Water Bureau


20 19 18 17 16 15

U 14 0 138 12I n § 10| 9

876543210

8/26/9110/15/91

12/4/911/23/92

3/13/925/2/92

6/21/928/10/92

DateFigure 4.90 Influent temperature levels, Portland Water Bureau

trend in lead levels was observed in Loops B and C, and in copper levels in Loop C. To evaluate if lead and copper levels stabilized after day 78 of the study period, the data from days 78 through 379 were also used to estimate trend lines. Figures 4.94 and 4.95 show the trend lines forthese data. Copper levels stabilized in all three loops, and lead levels stabilized in two of the three loops. The third loop, Loop C, still displayed a negative trend in lead levels.

The variability in lead and copper levels between each of the replicate loops was evaluated using a Wilcoxon matched pairs test. On the basis of this test, the lead levels from Loops A and B were not significantly different from each other, however, Loop C lead levels were significantly different from those of Loops A and B. These differences are displayed hi the box and whiskers plot in Figure 4.96. The copper levels from all three loops were not significantly differentfrom each other, according to the Wilcoxon matched pairs test.


• Loop A

+ Loop B

o Loop C

00

50100

,50 250 Time, days

350

• Loop A+ Loop B

o Loop C

0 50 10° 150 2°° 250 3°° 350 *»

Time, daysFigure 4.91 Standing lead and copper levels, Portland Water Bureau


0.5

0.4

£ S 0.3(A

1£ 0.2

0.1

0

Loop A

1

0.5

0.4

^ 0.3

•3 0.2

0.1

-0.1

100 200 Day

300 400

0.5

0.4

^ 0.3

•S 0.2>

JB1 0.12

o-0.1

LoopB

100 200 Day

300 400

LoopC

100 200 Day

300 400

Figure 4.92 Estimated trend lines for lead levels, all data, Portland Water Bureau


4.5

4

3.5

1b 3 E £ 2.5

Loop A

I 2

I 1 ' 5

0.5

0

S-.—'

100 200 Day

300 400

LoopB

400

400

Figure 4.93 Estimated trend lines for copper levels, all data, Portland Water Bureau


0.3

0.25

0.2

0.15

"i 0.1

0.05

0

Loop A

50 100 150 200 250 300 350 400Day

0.3

0.25

LoopB

•3 0.15

0.1

0.05

0.3

0.25

«d 0.200

| 0.15_u1 0.1J3

0.05

0

50 100 150 200 250 300 350 400Day

LoopC

50 100 150 200 250 300 350Day

400

Figure 4.94 Estimated trend lines for lead levels, days 78 through 379, Portland Water Bureau

4.5

4

3.5

60 3EX 2.5

Loop A

1

0.5

0,50 100 150

4.5

4

3.5

3

2.52

1.5

0.5

05

200 250 300 350 400 Day

LoopB

100 150 200 250 Day

300 350 400

i

4.5 4

3.5

£ 2.5 <uI 2

o O 1

0.5

LoopC

"50 100 150 200 250 300 350 400Day

Figure 4.95 Estimated trend lines for copper levels, days 78 through 379, Portland Water Bureau

<u(U

0.2

0.15

0.1

0.05

-0.05


Loop A Loop B Loop C

Figure 4.96 Box and whiskers plot of lead levels, Portland Water Bureau

Operational ConsistencyThe Portland Water Bureau pipe rack was operated for a total of 379

days, or54 weeks, between May 1991 andApril 1992. The pipe rack was checked weekly, at which time field water quality parameters were measured and standing samples were collected. No major complications or problems were reported during operation of the pipe rack, with the exception of minor leaks during the startup phase of the project.

During the operation of the pipe rack, the water bureau experienced two alterations in the quality of the water entering the pipe rack. These alterations were caused by the following operational changes. In September 1991, the water bureau changed its chlorine-ammonia ratio from 7:1 to 5:1. This trial ran for approximately 6 weeks. Also, in January 1992, the ammoniation point was moved downstream and the chlorination rate was increased from 1.8 to 2.1 mg/L. These changes were made to allow for more free chlorine contact tune to meet the CT requirements of the Surface Water Treatment Rule. The ammoniation rate was also adjusted in January 1992 to achieve a permanent 5:1 ratio.


Distribution System Data EvaluationSummary Statistics. Home tap samples were collected at approximately

80 homes at 8-week intervals from July 1991 through June 1992, for a total of six separate sampling events. Two standing samples were collected: a 250-mL sample followed by a 750-mL sample. Samples were collected from homes built between 1981 and 1983 that contained copper piping joined with lead solder. The total number of houses where both 250- and 750-mL samples were collected and analyzed for lead and copper levels was as follows:

Number of houses Sample Dateperiod sampled 250 mL 750 mL

1 7/12/91-7/26/91 74 772 9/13/91-9/20/91 78 783 11/15/91-11/22/91 75 764 1/10/92-1/17/92 71 725 3/13/92-3/20/92 71 716 5/29/92-6/5/92 70 72

All data 439 446

The lead and copper levels measured from these samples are listed in Appendix G. Lead levels from the 250-mL samples ranged from 0.001 to 0.286 mg/L, with an average of 0.025 mg/L. Lead levels from the 750-mL samples were lower, ranging from 0.001 to 0.150 mg/L, with an average of 0.014 mg/L. Forty- eight percent of the 250-mL samples and 24 percent of the 750-mL samples had lead levels higherthanthe regulatory action level of 15 ug/L. Copper levels were essentially the same for both the 250- and 750-mL standing samples collected at the tap, with average concentrations of 1.04 and 1.15 mg/L, respectively. Twenty-two percent of the 250-mL samples and 34 percent of the 750-mL samples had levels higher than the regulatory action level of 1.3 mg/L.

Lead and copper results from the 250- and 750-mL samples were also combined to obtain calculated 1,000-mL levels from these metals. These calculated results were compared to the action levels specified in the final Lead and Copper Rule. On the basis of calculated 1,000-mL lead and copper levels, the 90th percentile levels for these metals were as follows:

Sample period123456

Calculated 1,000-mL sample 90thpercentile levels

Lead (mg/L).043 .041 .036 .040 .035 .044

Copper(mg/L)1.80 1.75 1.25 1.53 1.63 1.86


All 90th percentile levels were greater than the action levels specified in the final Lead and Copper Rule.

To compare the home tap sample data with lead and copper levels measured from the pipe rack, the pipe rack data were divided into six sample periods that coincided with the six sampling events in the distribution system. Pipe rack data were collected weekly for approximately 54 weeks from three replicate test loops. Previous evaluation of the pipe rack data indicated that two of the three replicate loops provided metals levels that were statistically the same (i.e., one of the loops had lead levels that were statistically different from the other two). Therefore, the comparison of pipe rack data to distribution system tap data was completed using only data from the two similar replicate loops from the pipe rack, Loops A and B. Results from the pipe rack were then grouped into six sample periods based on their proximity to the distribution system sample period. Based on data from two of the three replicate loops, the number of lead and copper samples from the pipe rack for each of the sample periods was as follows:

Sample Pipe rack Number of Number of period study periods (dates) lead samples copper samples

1 6/12/91-8/20/91 14 142 8/21/91-10/18/91 16 163 10/19/91-12/16/91 16 164 12/17/91-2/14/92 16 165 2/15/92-4/29/92 22 226 4/29/92-6/2/92 20 20

All data 104 104

A comparison of the means, medians, and standard deviations for lead and copper levels from both the tap samples and the pipe rack samples is displayed in Table 4.24. The average and median lead and copper levels measured from the pipe rack were generally higher than the distribution system tap samples, with the exception of copper levels for sample periods 3 through 6. This difference can easily be seen hi Figures 4.97 and 4.98. The standard deviations for all lead and copper levels measured from the tap samples and the pipe rack are shown in Figures 4.99 and 4.100. The upper and lower boundaries of the +2 standard deviation lines shown for each sample period incorporate 95 percent of the data from that period. The wider the band, the greater the variation in lead levels measured for that sample period. Lead levels from the 750-mL samples displayed less variation than did those from the 250-mL samples. For sample periods 1 through 6 the pipe rack data exhibited a larger variation in lead levels than was seen in either the 250- or 750-mL samples, and the standard deviation of the copper levels from the pipe rack after the data approached stabilization (sample periods 3 through 6) was much lower than that of the tap sample. The variation in copper levels was similar for the 250- and 750-mL samples, and the standard deviation of the copper levels from the pipe rack after stabilization (sample periods 3 through 6) was much lower than that of the tap samples. The variation in lead and copper levels can also be evaluated based on the coefficient


Table 4.24 Summary statistics for lead and copper levels, pipe rack and distribution system tap samples, Portland Water Bureau

Average level

Tap samples

Sample Pipeperiod rack

Lead (mg/L)1 0.1952 0.0643 0.0524 0.0475 0.0496 0.041

Copper (mg/L)1 1.772 1.473 1.124 1.055 1.186 1.29

250mL

0.0290.0250.0220.0230.0220.026

1.111.060.870.981.051.20

750mL

0.0130.0140.0120.0130.0130.015.

1.181.140.961.151.181.29

Calculated1,OOOmL

0.0170.0170.0150.0160.0150.018

1.161.120.931.111.151.26

Piperack

0.1010.0310.0540.0050.0330.019

0.160.290.800.080.550.16

Standard deviation

Tap samples

250mL

0.0430.0380.0280.0390.0270.040

0.390.420.290.400.350.48

750mL

0.0170.0170.0140.0190.0210.020

0.510.480.360.450.420.58

Calculated1,OOOmL

0.0200.0180.0110.0210.0190.022

0.450.440.320.420.380.54

Piperack

0.1700.0570.0430.0460.0370.041

1.801.600.971.051.051.20

Median level

Tap samples

250mL

0.0180.0190.0140.0130.0140.013

1.151.100.891.001.001.20

750mL

0.0070.0090.0070.0060.0050.008

1.201.201.001.201.201.30

Calculated1,OOOmL

0.0100.0110.0090.0090.0090.012

1.181.140.981.151.201.30

of variation, which is measured as the ratio of the standard deviation divided by the mean. The higher the ratio, the less variability observed in the data. Table 4.25 contains a summary of the coefficients of variation for mean lead and copper levels. The ratios for lead levels from the pipe rack ranged from 1:1 to 1:9, and for calculated 1,000-mL samples the coefficients ranged from 1:0.8 to 1:1. Copper levels showed smallervariations than did the lead levels. Pipe rack copper data exhibited coefficients of variation ranging from 1:1 to 1:13, whereas coefficients from the tap samples were consistent between 1:2 and 1:4.

Finally, frequency distributions for lead and copper levels were calculated to evaluate whether these sample groups represented normal or nonnormal distributions. The lead levels measured from standing tap samples displayed nonnormal distributions, as seen in the frequency distribution curve for calculated 1,000-mL samples in Figure 4.101. Copper levels were much closer to a normal distribution (Figure 4.101). The lead and copper level distributions forpipe rack data can be seen in Figure 4.102. The lead data are nonnormally distributed, as are the copper data.

Statistical Difference in Metals Levels. To determine if the mean or median lead and copper levels measured at the tap were statistically different than those of the pipe rack samples, anonparametric Wilcoxon matched pairs test was performed using the average and median lead and copper levels for all six sample periods. Because the lead level data from the pipe rack approached stabilization after day 78 (sample period 3), the comparison of values was also made using values from sample periods 3 through 6.

Mean lead levels from the pipe rack were found to be significantly different from the 250-mL, 750-mL, and calculated 1,000-mL tap lead levels at the .05 p level using the Wilcoxon test for sample periods 1 through 6, and at the

<uJO

i

0.22

0.2

0.18

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

0

Average

• Racko 750 mL+ 250 mLA l,OOOmL

Sample period

IO

•a

0.22

0.2

0.18

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

0

Median

Sample period

Rack 750 mL 250 mL l.OOOmL

Figure 4.97 Average and median lead levels from Portland pipe rack and lead-soldered copper distribution system sites


1.9

1.8

1.7

1.6

j 1.5

I 1.4UO

f 1.3jou 19a§• 11U

1

0.9

0.8

Average

• Rack o 750 mL

mL mL

250i1,000

Sample period

U

1.9

1.8

1.7

1.6

"1.4

1.319

111

0.9

0.8

Median

• Racko 750 mL+ 250 mLA 1,000 mL

i T 3 i 5 r246

Sample periodFigure 4.98 Average and median copper levels from Portland pipe rack and lead-soldered copper distribution system sites

U.4D

0.4

0.35

1° 0.25% 0.2£ 0.151 0.1J 0.05

0-0.05

-0.1

.I 250-mL samples

•:7

•

: a•

D

1

a a a D aD a

2345

D a

6

D

• Mean

era 2 StandardError


Sample period

0.40.35

tJ 0.3|? 0.25

42" 0.2OJ

J5 0.15T3 0.1

3 0.05 0

-0.05-0.1

- -

750-mL samples~

---_

:- * * ^-

1

,"

--:

-.

* ^ T T

2345 6

-

|Mean

c=i 2 StandardError


Sample period

0.40.35

t4 0.3W) f\ s)Cc U.Zj

42" 0.2 u| 0.15•o 0.1<33 0.05

0-0.05

.A 1

•----.

_

i

Pipe rack samples

[J 3 [ ' ^ i= D a aI|Mean

en 2 StandardError


123456 Sample period

Figure 4.99 Box and whiskers plots of lead levels, Portland Water Bureau, tap samples and pipe rack samples

O

2.5

oo 2S

73 1-5

b iCX

§ 0.5

0

-0.5

•

.

•

: D

-

a Q a

:

1 2

f3

250-mL samples

i G a

4

-

--

D a c

_

a-.

BJMean

c=t 2 StandardError


5 6Sample period

3

2.5

*J 200S«* 1.5

1?"S 11o Q 5u

0

-0.5

"

.

-[i

.

j] [j r\

"""

1 2

D

750-mL samples

--

fi

a u

3

[]

4

--

1 D •-

--

.

3 i.

|Mean

1=1 2 StandardError


5 6Sample period

3

2.5

sJ 2e

JS 1-5u| 1uOH

& 0.5O

0

-0.5

-

_D

-

-pD

[ii _

-rj

-

-

1 2

i i

3

Pipe rack samples

*

4

i

~pi x i

' T :

|Mean

<=3 2 StandardError


5 6Sample period

Figure 4.100 Box and whiskers plots of copper levels, Portland Water Bureau, tap samples and pipe rack samples


Table 4.25 Ratios of standard deviation to mean for average lead and copper levels, Portland Water Bureau

Lead

Tap samples

Sample period

123456

Pipe rack

1:21:21:11:91:11:2

250 mL

1:0.71:0.71:0.81:0.61:0.81:0.7

750 mL

1:0.81:0.81:0.81:0.71:0.61:0.8

Calculated 1 ,OOOmL

1:11:11:1

1:0.81:0.81:0.8

Pipe rack

1:111:51:1

1:131:21:8

Copper

Tap samples

250 mL

1:21:21:31:21:31:2

750 mL

1:21:21:21:21:21:2

Calculated 1,000 mL

1:21:21:31:21:41:2

0.1 p level for sample periods 3 through 6. Mean copper levels from the pipe rack were not significantly different from those of the 750-mL or calculated 1,000-mL samples, butthey were different from those of the 250-mL samples. These results indicate that, whereas lead levels from the pipe rack were not the same as lead concentrations measured in the tap samples, the copper levels were similar.

Correlation of Lead and Copper Levels. Lead and copper levels from the pipe rack were also correlated to standing tap levels. The results of this evaluation are reported as a correlation coefficient, or r value. The correlation of the lead levels from the pipe rack to lead levels from the standing tap samples was completed using average and median lead levels from sample periods 3 through 6. This is the period during the study when the lead levels had stabilized in the pipe rack. The Spearman r values computed for the correlation of average lead levels from the pipe rack to the tap samples for sample periods 3 through 6 were as follows:


Pipe rack versus 250 mL Pipe rack versus 750 mL Pipe rack versus 1,000 mL

Spearman r value

- .80 (-.45) - .80 (+.20) -1.00 (-.26)

p level

.20 (.55)

.20 (.80) — (.74)


280Lead

8 5q £o o o d o o o o


«n— Expected

Copper

OOOOOOOOO

— Expected


Figure 4.101 Frequency distributions for lead and copper levels, Portland Water Bureau, calculated 1,000-mL tap samples


Lead

0.2 0.25 0.3 0.35 Category (upper limits)

0.4 0.45 0.5 0.55— Expected

Copper

— Expected

Category (upper limits)Figure 4.102 Frequency distributions for lead and copper levels, Portland Water Bureau, lead-soldered copper pipe rack

Correlations and p levels for median lead levels are given in parentheses. The r values for the relationship between lead levels in the pipe rack and lead levels from 250-mL samples are very low and indicate a lack of correlation. The correlation between pipe rack lead levels and lead levels from the 750-mL and calculated 1,000-mL samples was negative; i.e., high lead levels from the pipe rack corresponded to low lead levels in the tap samples. Only two of the individual houses exhibited a significant correlation (p level < .05) to lead levels from the rack. As with the previous results for Contra Costa, this information provides little assurance that pipe rack lead results actually represent distribution system standing lead levels. The correlation for copper levels was somewhat more promising, however. The Spearman r values computed for the correlation of average copper levels from the pipe rack to the tap samples were as follows:



Nineteen of the houses showed the same correlation (p level < .2) when evaluated individually. In summary, when the lead levels measured from the pipe rack are compared to lead levels measured from standing tap samples, there is essentially no correlation in actual levels. Copper levels from the pipe rack were more closely correlated to tap samples; however, these correlations were not very significant.

Utility Data Comparison and Summary of Findings

The previous sections of this chapter have described the specific results obtained from several pipe rack operations. These studies were undertaken to provide data and information for recommending a protocol for use of the AWWARF pipe rack for lead control. This section compares the results from each of these studies and provides a summary of the findings.

Pipe Rack Data ComparisonMetals Levels

The lead and copper levels measured from each of the pipe rack studies are a function of a variety of conditions, including incoming water quality for each utility, the treated water quality conditions to which each loop was exposed, materials variations, workmanship, sampling variability, etc. In general, lead loops exhibited lead levels that were at least a factor of 10 higher than lead levels


from the lead-soldered copper loops. This result would be expected, given the larger source of lead in the lead pipe. The ISWS had the lowest lead levels from a lead-soldered copper rack, and the highest levels were measured in the Philadelphia loops and two of the New York City loops. Four of the utilities documented the average amounts of solder used in constructing each test loop. These average amounts are shown below, along with the average and median standing lead levels measured from each of the utilities' test racks.

Averagesolder/loop Average Median

Utility (g) lead level (mg/L) lead level (mg/L)

ISWS 55 0.0012 0.007Contra Costa 61 0.018 0.010Fort Worth 59 0.009 0.007Portland 33 0.063 0.040

The highest lead levels were measured from test loops containing the least amount of solder; however, Portland's water is likely more corrosive than water from the other three participants.

Whereas only New York City incorporated copper-only loops into its pipe racks, the copper levels from the Catskill Delaware copper loops were comparable to those of the lead-soldered copper loops. Copper levels measured from the copper control loop were also similar to copper levels measured from Portland's lead-soldered copper loops, where similar influent pH and alkalinity levels were measured. A summary of the average lead and copper levels measured from all pipe racks is presented in Table 4.26.

Data distributions were also calculated for metals levels measured from the pipe racks. In all cases, the lead levels measured from standing test loop samples exhibited nonnormal distributions skewed to the left; i.e., several very high lead levels were measured throughout the study period. Copper levels, although also nonnormal, more closely approximated normal distributions. The nonnormal distribution of the data, along with the generally low number of samples with which to evaluate treatment differences, provides evidence that nonparametric data evaluation techniques may be the most appropriate for evaluating data from pipe rack studies.

Influent Water QualityISWS, Contra Costa, Fort Worth, and Portland all measured incoming

water quality characteristics frequently during the study. New York City measured raw water characteristics for the first 2 months but discontinued analysis because the parameters remained relatively consistent. Both Contra Costa and Fort Worth experienced wide variations for several incoming water quality parameters. The lead levels from the pipe racks at both utilities were also somewhat erratic; however, the copper levels at Contra Costa were relatively consistent after stabilization had occurred. Portland's influent water quality was very consistent throughout the study, as were the lead and copper levels after stabilization. ISWS also maintained relatively consistent incoming water quality, with the exception of the short-term treatment interruption when lime softening was discontinued


Table 4.26 Comparison of pipe rack water quality data from all pipe rack studies

Utility

New YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkPhiladelphiaPhiladelphiaPhiladelphiaFort WorthFort WorthFort WorthNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkPhiladelphiaPhiladelphiaPhiladelphiaFort WorthFort WorthFort WorthContra CostaContra CostaContra CostaPortlandPortlandPortlandISWSISWSISWSNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew York

Pipe rack location

CrotonC no tonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareBaxterBaxterBaxterComoComoComoCrotonCrotonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareBaxterBaxterBaxterAltaMesaAlia MesaAltaMesa

CrotonCrotonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill Delaware

Average Average Influent pt,

waterquallty lawj,Type of loop

LeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperCopperCopperCopperCopperCopperCopperCopperCopper

Treatment

ControlZincorthophosphateControlpH7.5ZincorthophosphateZincorthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphateControlZincorthophosphate, 1 :3Zincorthophosphate, 1:10Control, Loop 1Control, Loop 2Control, Loop3ControlZinc orthophosphateControlpH7.5ZincorthophosphateZincorthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphateControlZincorthophosphate, 1:3Zincorthophosphate, 1:10Control, Loop 1Control, Loop 2Control, LoopsControl, Loop 1Control, Loop 2Control, Loop 3Control, Loop 1Control, Loop 2Control, LoopsControl, Loop 1Control, Loop 2Control, LoopsControlZincorthophosphateControlpH7.5Zinc orthophosphateZincorthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphate

pH

7.097.096.76.76.76.76.76.78.18.08.08.18.18.17.097.096.76.76.76.76.76.78.18.08.08.18.18.18.08.08.06.96.96.98.918.918.917.097.096.76.76.76.76.76.7

Alkalinity

63.763.7

9.39.39.39.39.39.3———

116.7116.7116.763.763.7

9.39.39.39.39.39.3———

10310310367.767.767.7

7.37.37.3

127.5127.5127.563.763.7

9.39.39.39.39.39.3

(mg/L)

1.220.161.970.590.450.19980.490.311.210.670.80.260.230.180.180.0410.0310.0580.0240.0780.0730.1330.1920.2070.2790.0080.01040.0080.0250.0150.0140.0620.0770.0490.00180.00090.0009

————————

Average Cu

level (mg/L)

——————————————

1.151.032.010.611.010.190.571.10.250.160.0540.550.560.540.270.270.281.31.31.30.410.380.361.1950.961.970.590.450.20.490.31


and of the periodic switching from free chlorine to a combined chlorine residual. Copper concentrations increased slightly (from 0.2 to 0.5 mg/L) when the utility switched from free to combined chlorine. New York City may have experienced an influent water quality change during February 1992 because several of the test loops showed very high lead and/or copper levels. Incoming water quality conditions were not documented at that time, so the cause of these high levels could not be determined.

Variability of Metals LevelsThe variability of the lead and copper levels measured from the pipe racks

was very similar, even given the wide range of incoming water quality conditions. The ratios of the standard deviation to the mean for lead levels from the lead loops ranged from 1:0.3 to 1:2, and for lead levels from lead-soldered copper loops the ratios ranged from 1:0.5 to 1:4. Copper levels were generally less variable, with ratios as high as 1:5. The variability of copper levels from both copper-only loops and from lead-soldered copper loops was similar. Table 4.27 presents a summary of the ratios of the standard deviation to the mean for lead and copper levels measured from all of the test loops. The average ratios for each type of test loop material were as follows:

Ratios of standard deviation to mean

Test loop material Lead levels Copper levelsLead 1:1 —Lead-soldered copper 1:1 1:2Copper — 1:2

The wide range of metals levels measured throughout the study period for these pipe racks could be caused by one or all of the following:

• stabilization of the corrosion process as the piping material ages• seasonal or operational changes in incoming water quality• inability to maintain consistent treated water quality conditions• unexplained disturbances to the pipe rackIn several of the studies, initially high metals levels decreased and

exhibited less variation as the piping material aged and the corrosion processes stabilized. This pattern was especially true for copper levels; lead levels were generally much more erratic. Although some studies displayed a lower range of lead levels as the study progressed, the majority exhibited occasional extremely high lead levels throughout the study period.

The variability measured in lead and copper levels from several of these studies may also be due to seasonal or operational changes in incoming water quality. The ISWS study had a documented change in water quality conditions that resulted in significantly higher metals levels. Several of the New York City loops also experienced what appeared to be short-term changes in incoming water quality that may have resulted in the elevated lead levels measured from the lead loops and the elevated copper levels from both the copper loops and the


Table 4.27 Comparison of ratios of standard deviation to mean for lead and copper levels from all pipe rack studies

Utility

New YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkPhiladelphiaPhiladelphiaPhiladelphiaFort WorthFort WorthFort WorthNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkPhiladelphiaPhiladelphiaPhiladelphiaFort WorthFort WorthFort WorthContra CostaContra CostaContra CostaPortlandPortlandPortlandISWSISWSISWSNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew YorkNew York

Pipe rack location

CrotonCrotonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareBaxterBaxterBaxterComoComoComoCrotonCrotonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareBaxterBaxterBaxterAlta MesaAlta MesaAlta Mesa

CrotonCrotonCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill DelawareCatskill Delaware

Ratio of standard deviation to mean

Type of loop

LeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadLeadSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperSoldered copperCopperCopperCopperCopperCopperCopperCopperCopper

Treatment

ControlZinc orthophosphateControlpH7.5Zinc orthophosphateZinc orthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphateControlZinc orthophosphate, 1:3Zinc orthophosphate, 1:10Control, Loop 1Control, Loop 2Control, Loop 3ControlZinc orthophosphateControlpH7.5Zinc orthophosphateZinc orthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphateControlZinc orthophosphate, 1:3Zinc orthophosphate, 1:10Control, Loop 1Control, Loop 2Control, Loop 3Control, Loop 1Control, Loop 2Control, Loop 3Control, Loop 1Control, Loop 2Control, Loop 3Control, Loop 1Control, Loop 2Control, Loop 3ControlZinc orthophosphateControlpH7.5Zinc orthophosphateZinc orthophosphate, pH 7.5Blended orthophosphate, pH 7.5Blended orthophosphate

Pb levels

1:21:21:21:0.71:11:0.81:0.61:11:0.31:0.41:0.41:11:1.51:11:21:0.71:11:11:11:0.41:0.81:0.41:11:11:11:0.61:0.51:0.81:11:0.81:0.91:1.51:0.91:0.71:0.61:0.51:0.7———————*"^~

Cu levels

_—————————————

1:21:31:51:0.71:21:21:21:11:31:41:11:21:21:21:2.51:31:2.81:31:2.61:3.81:11:11:11:31:31:31:11:11:11:0.51:1.5

Note. Cu levels were not measured for lead loops; Pb levels were not measured for copper-only loops.


lead-soldered copper loops. Seasonal water quality changes may have also impacted the metals levels for several of these studies; however, without several years' worth of data, this impact is difficult to evaluate. Philadelphia and New York City both reported difficulties in maintaining consistent treated water quality conditions, which may also have resulted in erratic metals levels during the course of the study. Finally, undocumented physical disturbances to the pipe, such as vibration or something accidentally hitting the pipe, may have dislodged corrosion products and produced elevated and unstable metals levels.

The variability measured in metals levels from a pipe rack plays an important role in determining the optimum frequency of sampling from a pipe rack. If the expected ratio of the standard deviation to the mean for metals levels is relatively high (i.e., 1:1 or 1:2), more samples will need to be collected to provide statistical confidence in the results. The variabilities measured in lead and copper levels from these studies provide a starting point for determining appropriate sampling frequencies for pipe rack studies.

Stabilization of Metals LevelsThe length of time necessary to operate a pipe rack is dependent on when

metals levels stabilize to a point at which treatment differences can be detected. Because new materials were used in the AWWARF pipe rack, the formation of films and stabilization of the corrosion process must be established foreach water quality condition before a comparison in metals levels can be made. Stabilization of metals levels may be seasonal in nature if incoming water quality conditions are also seasonal; i.e., levels may stabilize during one period of the year, after which they may increase and then restabilize during another period. Several years' worth of data may be needed in order to evaluate seasonal effects. The utilities participating in this study all operated their pipe racks for approximately 1 year, and therefore seasonal changes in metals levels could not be detected. However, results from these pipe rack studies provided initial estimates of the minimum time needed to obtain somewhat stable metals levels. The following table summarizes the range of stabilization periods required for metals levels from the utilities participating in this study:

Time needed to stabilize (days)Pipe loop material Lead levels Copper levels

Lead 180-280 —Lead-soldered copper 78-245 50-180Copper — 230

Lead and copper results from several racks still appeared to be decreasing with time after 1 year of operation, although there were also instances in which the levels remained relatively stable from the beginning of the study. In general, however, 6 td 9 months were needed to obtain stable lead levels from lead test loops, and between 3 and 8 months for levels from lead-soldered copper loops. Copper levels from lead-soldered copper loops or from copper loops required from 2 to 8 months to reach stable levels.


Replicate LoopsThree utilities and the IS WS incorporated three replicate loops into their

pipe racks to evaluate the variability of metals levels between similar test loops. If similar metals levels exhibiting similar variabilities were measured from all three test loops, then replicate loops might not be needed in the pipe rack. Results from the replicate lead loops at Fort Worth indicated that one loop produced lead levels significantly different from those of the other two. This was also the case for lead levels measured from the lead-soldered copper loops at ISWS, Contra Costa, and Portland. Fort Worth's lead-soldered copper rack exhibited similar lead levels for all three loops, however. Copper levels from all pipe racks were similar for the three test loops. These results indicate that if lead is the metal of interest, then a minimum of three test loops should be incorporated into the pipe rack. If copper is the primary focus, however, one lead-soldered copper pipe loop should be sufficient.

Distribution System DataThree utilities, Contra Costa, Fort Worth, and Portland, conducted home

tap monitoring in addition to constructing and operating an A WWARF pipe rack. Their results provided information on the correlation of pipe rack metals levels to metals levels measured from standing tap samples. The following discussion summarizes and compares these correlations.

Correlations by Sample Period, Lead-Soldered Copper SitesAll three utilities collected tap samples from lead-soldered distribution

system sites. These metals levels were grouped into several sampling periods over the course of the 1-year study to determine if

• metals levels measured from home tap samples were similar to metals levels measured from the pipe rack

• metals levels measured over the course of the year from a pipe rack exhibited the same changes as metals levels measured from home tap samples; i.e., if seasonal changes in metals levels from the pipe rack would correlate to seasonal changes in metals levels in the distribution system

Table 4.28 summarizes the results obtained from the three distribution system correlation studies in which lead-soldered sites were used. Lead levels measured from the pipe racks were higher than lead levels measured from home tap samples, with the exception of Fort Worth. In Fort Worth, the average lead levels measured from the pipe rack for each sample period ranged from 2 to 20 ug/L, whereas the levels of calculated 1,000-mL samples were very similar, ranging from 3 to 8 ug/L. Copper levels measured in home tap samples were very similar to pipe rack levels. Whereas copper levels from Contra Costa's pipe rack were twice the levels measured from the home samples, both were relatively low (0.2 to 0.56 mg/L for the pipe rack and 0.09 to 0.14 mg/L from calculated 1,000-mL samples).


Table 4.28 Summary of comparison between tap and pipe rack metals levels for lead-soldered copper materials__________________________

Similar levels Pipe rack metalsfor pipe rack levels correlated

Utility and tap samples to tap samples

LeadContra CostaFort WorthPortland

CopperContra CostaFort WorthPortland

noyes*no

noyesyes*

nonono

yesnono

* Applies to pipe rack metals levels after stabilization

Table 4.29 Summary of comparison between tap and pipe rack lead levels for lead service connections_________________________________

Similar levels Pipe rack metalsfor pipe rack levels correlated

Sample number and tap samples to tap samples

1 (no flush) 2 (1 -minute flush)

no no

no yes*

* Using median lead levels

Correlations by Sample Period, Lead Service SitesFort Worth was the only utility that collected home tap samples from sites

with lead service connections. Results were as shown in Table 4.29. Lead levels from the pipe rack were much higher than those of the tap samples, between .2 and .4 mg/L for the pipe rack versus approximately 0.01 mg/L for the tap samples.


Summary of Findings Startup Procedures

Hot water flushing (150 to 160°F [60 to 70°C]) was effective inreducing zinc contaminants from lead-soldered copper test loops.Copper levels were not reduced by repeated hot water flushingevents.Lead levels decreased with each consecutive hot water flushingevent.

Construction and Operation

Clear specifications and materials lists facilitated construction.Pipe rack materials were found to be readily available to allparticipating utilities, with the exception of lead pipe, which hadto be specially ordered from a manufacturer.Occasional leak repair was necessary for several of the piperacks, particularly immediately after construction.During pipe rack startup, a tendency for the chemical solution tosettle was discovered. Crystal formation in the bulk zincorthophosphate solution due to the freezing point of the chemicalmay have been a contributing factor.High heterotrophic bacteria counts were measured in loops atseveral of the participating utilities, either immediately afterconstruction or during periods of wanner water temperatures.Coordination with laboratory support personnel was important inassuring timely analyses of pipe rack samples.

Pipe Rack Data Characteristics

The distribution of lead levels from the pipe racks was generally nonnormal. Copper levels were also nonnormally distributed; however, the data more closely resembled a normal distribution. Copper levels from both lead-soldered copper loops and copper loops were similar under the same water quality conditions. In the studies with three replicate test loops of lead or lead- soldered copper, one loop usually produced lead levels statistically different from the other two loops. Copper levels were statistically similar for all three loops in the lead-soldered copper test loops.A wide range of lead and copper levels was measured from the pipe racks throughout the study period, and unexplained high lead levels were common.Similar variabilities in lead and copper levels from the pipe racks were observed by the various study participants. The average ratios of the standard deviation to the mean for lead and copper levels for the various test loop materials were as follows:


Ratios of standard deviation to mean

Pipe loop material Lead levels Copper levelsLead 1:1 —Lead-soldered copper 1:1 1:2Copper — 1:2

• Standing metals levels in the pipe rack responded to a treatment interruption that resulted in pH and alkalinity changes (a reduction of approximately one pH unit) in incoming water quality in the ISWS study.

• In the treatment evaluation studies, the difference in metals levels under different water quality conditions could be determined using nonparametric statistical techniques; however, the variability in the data was high.

Stability of Metals Levels From the Pipe Rack

• Several of the studies showed lower variability in metals levels as the studies progressed.

• Lead and copper levels from several of the studies appeared to decrease, i.e., stabilize, with time. The time required for lead and copper levels to stabilize in several of the racks was as follows:

Time to stabilize (days)Pipe loop material Lead levels Copper levelsLead loops 180-280 —Lead-soldered copper 78-245 50-180Copper — 230

• Lead and copper levels from several racks still appeared to be decreasing with time after lyear of operation, although the rate of decline was much slower.

Distribution System Correlations

• Lead levels measured from the lead-soldered copper pipe racks were higher than lead levels measured from tap samples, with the exception of Fort Worth, where the lead levels were similar.

• Copper levels measured in home tap samples were very similar to pipe rack levels after stabilization.


Lead and copper levels from the lead-soldered pipe racks were notcorrelated (p level > 0.2) to lead and copper levels from tapsamples, with the exception of copper levels from Contra Costa,which showed a high degree of correlation (Spearman r = .98, plevel = .005).Lead levels from the lead pipe rack were much higher than thoseof tap samples from lead service sites.Median lead levels from the lead pipe rack were significantlycorrelated (at the .1 p level) to median lead levels from the tapsamples collected after a 1-minute flush.

Chapter 5

Future Research NeedsSeveral potential research needs were identified during the course of this

study. These needs are identified below.This study evaluated the impact of hot water flushing on the leaching

characteristics of lead-soldered copper pipe. The impact of this flushing procedure on lead pipe, copper pipe, and brass should also be investigated in order to evaluate the potential effect of increased water temperature on the corrosion process hi these materials.

In addition to the startup flushing procedure, a standardized protocol for a preconditioning period for the test loops in the pipe rack should be established under various water quality conditions. A preconditioning period involves operation of the pipe rack for aperiod of time afterflushing but before chemical treatments are started. Data results from the preconditioning period would be used to determine if all test loops were constructed similarly and yielded similar results, as well as to provide similar starting points for evaluating treatment effects on leaching. The protocol should include an investigation of the proper data evaluation techniques to apply to leaching data generated during this period of a pipe rack study.

With respect to normal operating conditions, further refinement of the data characteristics expected from the AWWARF pipe rack should be undertaken. This work includes additional study of the time required for stable lead and copper levels to be measured under various water quality conditions, as well as study of typical variabilities measured in metals levels from the pipe racks. The impact of seasonal water quality changes on lead and copper levels measured from the AWWARF pipe rack, the operating time necessary to properly evaluate corrosion treatments given seasonal influent water quality conditions, and the most appropriate data evaluation techniques to apply under these conditions should be incorporated.

Corrosion control chemicals may be transformed in the distribution system. Studies to evaluate this transformation, as well as to determine how to simulate this change in the AWWARF pipe rack, should also be conducted.

Finally, development of tests aimed at evaluating the secondary impacts of corrosion control treatments, particularly nutrient effects, would expand the amount of useful information that can be gathered using the AWWARF pipe rack.

261

Appendix A__________

Schematics for Historical Pipe Loop Studies

1 1/4 in. • Pipe Nipple 10 In. (254 mm) Length

.——ffV^S**)———————~)————WWWN^VXV* [-«-—.

P***-^ 11/4ln.-x1 In.-Burning

1 in. •• Service Line. 1.66 In. or 42.16 mm O.D. •• 1.315 In. or 33.40 mm O.D.

L 1ISWS Corro«kMi Te.ter

Source: ASTM D2688-83 1983Cross section of insert, spacer, and union, assembled ISWS corrosion tester

263


Flexible Nipple Headpiece

Pipe Coupon e Acrylic Sleeve

3 ^Plunger

Union Coupling

O-RIng

Source: Reiber, Ferguson, and Benjamin. 1988Cross section of modified ISWS corrosion tester

Appendix A: Schematics for Pipe Loop Studies 265

Supply

MATERIAL LISTINGMixer - StaticV. • Main Water Supply Shut-off ValvePRV • Pressure Regulating ValveV, • Test Loop Isolation ValvesPC • Flow Rate Controller, PVC, 3 GPMFR - Rotameter, 0-5 GPMM - Water Meter, TotalizingC • Corrosion CouponsCERL - Pipe SpecimensV, • Sample Valve, 1/4"Pipe • Fittings • 3/4", SCH. 40, PVC

Source: Temkar et al. 1989Schematic of USA-CERL pipe loop system

Lead Coupons/ \

4" 4" 4"

: 12"

r i: 4"

f!12",

•*-L Bf ft12" ! :

.L fV$8=«# i:y 4"

Copper Loop - n-ft-x

xfl ———— KXXXXX) —— UA ' Sample

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ff : <4 Ba"7 ti : Valve

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jj.'

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u u\ /-

Lead Coupons

ATT

BallValw« Loop B

i

Oi

?«^Sample

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=4 BallValve

itlet

Source: Temkar et al. 1989Schematic of experimental setup for CERL lead dissolution study

5 S a 3£ « - «!j

2 GPM Flow ———— »

Stagnant — —

c

1 1 11 i

i

c

AV

j1Hr. 5Hr. 15Hr.

i *L iV

0800 0900 1000 1100 1600 1700 0800

Clock Time

Source: Temkar et al. 1989USA-CERL pipe loop system lead dissolution study: Sampling protocol


Constant Head (3.7 m) Reservoir

CorrosionInhibitor

Chemical FeedSystem

Galvanized Steel Pipe Sleeve Corrosion Test Units—2 Test Coupons per Test Unit

• Static Mixer

11, .ir n> fp-2.5 cm PVC Pipe

-ill___LlrJT tfl-"•J Black Steel Pipe Sleeve Corrosion Test

Units—2 Test Coupons per Test Unit

Copper Pipe Sleeve Corrosion Test Units—2 Test Coupons per Test Unit

To drain

' Throttling Valve 1.9 cm Rotating Disc Water Meter

Continuous Flow Test Unit

Tygon Tubing ^

51 cm Galvanized Steel Pipe (0.64 cm diam.)

To drainThrottling Screw Clamp -^, .

25 cm Copper Pipe(0.64 cm diam.)

(Added after 148 days)

Metal Pick-up Test Unit

• 51 cm Copper Pipe With Lead/Tin Solder

(0.64 cm diam.)

cm Copper Pipe WithTin/Antimony Solder

(0.64 cm diam.)

Source: Herrera et al. 1981 -1983Metal pickup test unit: solder comparison study (Seattle Water Department)

^.Corrosion Inhibitor Chemical

_ —————— . ——— f\ ^-Chemical /"I Chemical PumD**"^ Tubing / tr-§ s- 500 Gallon Tank

—— + To Drain « —— From Water

f 1/2" PVC (Typ.) -"* " V _. . U77- — — ' Supply Inhibited ^-Chemical Injection

Water Supply Standpipe 1/2" PVC

-T- f Pressure Regulator1/2" Gate Jt \ Q~£ressure ,«>, S Valve -^$ \ X Gage-5 PSI/

Sample £ Cock ——— *

Linear Polarization •• •Probe for Black ___ .— Q—Steel —

"M" PVC Pipe (Typ.)

f|< ————— jj, ——

—— h1 T — iCopper Pipe Sleeve Corrosion Units— 2/'J^--—' Test Coupons per Test Unit ———— — ~~

To Drain *— t- -«— *-< —— ' — ' ——— >-* ——— J-* —

i

'Sample JCock— "2

«

5•Sample ^Cock —•'4

galvanized Steel Pipe Sleeve Corrosion [ Units— 2 Test Coupons per Test Unit

1"GS Lfi —————— ,]| f ^- 1 1/2" PVC (TvD.)

• f- Linear Polarization ~~O Probe for Galvanized

Steel

_ i_ Black Steel Pipe Sleeve Corrosion TestUnits — 2 Test Coupons per Test Unit

• r— Linear Polarization 7~O Probe for Copper

V ' S. r*' N Throttling X — »- 3/4" Rotating Disc Water Meter>• Valve

ISWS Test Unit (Typ.)

f Copper Pipe ^ 3/4" PVC (Typ.)

[ /'Galvanized Steel Piperr —? <^-Sample

i CockTo Drain

• Metal Pickup

. ^- Sampleff Cock

To Drain

Test Unit (Typ.)

^Class 150 AC 4" Pipe (Typ.)

L*HI II _J M » To Drain

Microscopy Test Coupons

Asbestos Cement Test Unit (Typ.)

Source: Herrera et al. 1981-1983Corrosion inhibitor pilot plant test assembly (Seattle Water Department Internal Corrosion Study)


/Timed Black Iron j^/ Valve

Strainer* for rj

Mixing -— B (Bull Run \ 1

Only) V I

Chlorine Addition —— * (Bull Run

Only)

Raw Water Influent

. ———— •* —— 1

!

Sample"L

36 0 12 IS 18

Galvanized Steel T

36 9 12 W W KXJ

Copper T

36 9 12 15 18 *"

Lead Coated Copper T

36 9 12 15 18 ^^

Lead T

36 9 12 15 18

Asbeslo* Concrete -r

36 9 12 15 18 ^*

J^,220' Coll of -J 1 A ' —— ' Copper Tublnfl - ——— ~~~~^^\ C^^- Sample

^r^J T"P Dr iln

Source: Montgomery Inc. 1982Portland pilot plant facilities schematic showing metal type and length of exposure inmonths

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Appendix B.1

Construction and Operation Procedures Originally Recommended to Utility Participants

RECOMMENDED AWWARF PIPE RACK CONSTRUCTION

Manifold Construction

Schedule 80, Polyvinyl chloride (PVC) pipe was recommended for use in the manifold plumbing to provide added rigidity in the model. The piping manifold for the influent and effluent streams was to be constructed from 3/4-inch PVC and fittings while the pipe material test sections incorporated 1/2 PVC pipe and fittings. Threaded connections were recommended for equipment connections or where pipe removal might occur (Note: Recommended protocol may include flanged or coupled fitting rather than threaded connections). PVC pipe solvent was recommended for joining socket fittings and pipe to assure permanent pipe alignment.

PVC check valves were recommended to isolate the pipe test sections during no-flow conditions. The check valves would reduce the effects from diffusion and thermal currents which could increase the variability in the observed metal concentrations. PVC sample valves were to be located as near to the outlet side of the pipe test section as practical to reduce the sample volume not in contact with the pipe material.

Teflon (R) tape was recommended for use with threaded PVC pipe connections. The tape was to be applied to the threads, and the fittings hand tightened. The use of paste-type sealants was not encouraged, as they could contaminate the system. The utilities were instructed to avoid excessive tightening of the PVC fittings which could cause fittings to split during operation.

Note: This document has been modified by results from this study.

273


Socket PVC fittings could also be used, however utilities were encouraged to avoid the application of excessive solvent.

Construction of Replicate Test Sections

The participating utilities were instructed to build the test loop sections using standard plumbing practices. All pipe material was to be inspected for defects and uniformity. Pipe ends were to be reamed to remove any material which could cause flow distortion in the loop. The following pipe test sections were recommended for use in construction of the replicate test loops.

Lead Tube

New lead tube was to be purchased directly from a manufacturer specializing in extruded lead products. Tube dimensions used in the original AWWARF pipe rack built at the Illinois State Water Survey (ISWS) were specified to be 0.50 inch I.D. with 0.25 inch wall. Other dimensions could be used, particularly if lead pipe for a specific utility or distribution system area differed from 0.50 inch I.D. The length and diameter of the lead tube test section determined the total volume of water available for chemical analysis.

The total length of lead tube was to be cut into three test sections of equal length, formed into loops, and lead solder used to externally connect the vertical sections to increase loop rigidity. The lead loops were to be connected to the PVC pipe section using reinforced PVC tubing and ordinary hose clamps.

Soldered Copper Tube

New copper tube and fittings were to be used to construct the three soldered copper pipe test sections. Type L, 1/2-inch copper tube was specified. Sixty feet of hard temper copper tube was recommended to construct each section. The tube was to be cut into 36-inch vertical lengths and 6-inch horizontal lengths, and each tube end reamed to remove the internal deformation caused by the cutting process. It was recommended that a licensed plumber construct the pipe sections. The copper tube was to be jointed to 90 degree copper elbows by 50-50 lead-tin solid core solder. The tube ends and fittings were to be cleaned and lightly brushed with flux and soldered fillings were to be carefully joined to copper tube without the use of excess solder or flux.. The plumber was to be provided with a preweighed roll of solder. Based on the ISWS pipe rack construction, solder usage averaged approximately 0.70 g per fitting-end for the 36

Appendix B.I: Procedures Originally Recommended 275

elbows in each section. This is equivalent to 0.17 Ib per 100 joints, much less than the 0.40 Ib per 100 joints estimated by the CD A handbook. The weight of solder used for each loop was to be documented to enable calculation of the amount of solder used per joint. Horizontal fittings were preferred over vertical fittings to prevent gravity flow of solder and flux into the pipe interior. For utilities assembling multiple pipe sections, the plumber was to be instructed to not complete one pipe loop when soldering joints and then move onto the second loop to complete it. Rather, the plumber was to layout all components of each loop loosely and solder one joint in each loop in a consecutive manner. For example, if there are 5 joints to be soldered in each of 3 loops (15 total) the following sequence for soldering could be used:

Soldering Sequence for Pipe Loop Assembly

Loop 1_Jl

123

123

456

789

101112

131415

This method was encouraged in order to reduce the variability between loops. Using this method, a preweighed amount of solder would be set aside for each test section. When moving between replicate test loops to solder joints, the specific solder set aside for that section would be used. This allowed the total amount of solder used per test loop section to be determined.

The soldered copper tube test sections were to be connected to the PVC piping by a 1/2- inch copper tube adapter. Approximately 2800 mL of water was contained in the assembled pipe test section, averaging one lead solder joint per 20-inch of copper tube. Although the joint density is likely greater than found in a typical plumbing system, the higher density would most likely increase the sensitivity to lead dissolution caused by changes in water corrosivity.

RECOMMENDED AWWARF PIPE RACK OPERATIONS

Water usage, flow rate, and pressure were the only environmental factors controlled during operation of the AWWARF pipe rack. A 3/4-inch nonmetallic water meter was recommended to register total water usage (gal). Each material test section was to be equipped with a 1/4-inch variable flow rate meter with a range of 0 to 2 gpm. Fluid velocity would be controlled by adjusting the ball valve on the outlet-side of each test section to the desired flow rate. An electrically powered, 3/4-inch solenoid valve was recommended on the discharge


manifold to maintain system pressure in the pipe rack during the non-flow conditions as would occur in household plumbing. A brass body valve could be used to reduce costs since the water was being discharged from the loop and metal contamination was not a concern at this location. The action of the solenoid valve was to be controlled by an electronic timer. A programmable microprocessor circuit was recommended to accurately control six on-off operations per day. A 3/4-inch PVC pressure regulating valve, installed near the inlet to the pipe rack, was recommended to minimize pressure fluctuations which could result in a corresponding flow rate variation in the pipe loop.

Start-Up Procedures

Preconditioning the test loops was recommended to clean the exposed metal surfaces of contaminants resulting from the fabrication process and to condition the metal surface to produce metal dissolution values more realistic of equilibrium conditions. Obviously the pipe loops must be free of debris and extraneous surface films. Inspection of the pipe materials prior to fabrication should have detected unsuitable materials and should have ensured that the pipe loops were assembled from new, clean, and uniform material. During the fabrication, some contamination of the pipe loops may be unavoidable for certain materials, i.e. flux in soldered jointed copper tube. Therefore a nonaggressive cleaning procedure was recommended to remove the contaminants or to at least reduce the effect of their presence to a consistent acceptable level.

Based on the ISWS investigation of hot water flushing using lead-soldered copper tube materials, the following procedures were recommended to participating utilities to precondition pipe loops.

Solder Jointed Copper Tube

After the loop fabrication was completed, and before placement in the pipe-rack, the loop was to be flushed with 150 deg. F water for 3 hours. Flow rate through the loop was to be maintained at 0.5 gpm (.7 fps).

Lead Tube

After the loop fabrication was completed and before placement in the pipe-rack, the loop was to be flushed with 150 deg. F water for 4 days. Water velocity was to be maintained at 0.7 fps through the loop during flushing.


After the AWWARF test loops were pre-conditioned, they were to be installed immediately into the pipe rack, filled with water, and operation begun immediately. In addition to the pre conditioning procedures, it was recommended that the sample taps be disinfected prior to their placement in the pipe rack.

Normal Corrosion Test Operation

The original AWWARF Pipe Rack Model was initially set up to operate on a schedule convenient for ISWS laboratory personnel. The 8-hour standing time was programmed to occur during office hours, with running samples collected and tests made between 8:00 and 8:30 AM, while water was flowing through the loop. Standing samples were collected at approximately 4:30 PM. The same timer cycle was recommended to the participating utilities as follows:

Time7:308:304:305:007:308:00

10:3011:00

1:302:004:305:00

AMAMPMPMPMPMPMPMAMAMAMAM

Cvcle Modeonoffonoffonoffonoffonoffonoff

On-off cycles could be shifted depending on each utility's operations and laboratory requirements.

Flow rates were to be set at 1.0 gpm through each section of the pipe loop. Total water flow would then range from 180 to 210 gpd per loop depending upon time requirements for sampling. A daily log of operational readings was to be kept for each pipe rack.


Pipe Rack Sampling

Recommended water quality sampling for normal corrosion operations was divided into monitoring of influent running samples and first flush sampling from each of the loops. The running samples would provide information on operational consistency and background water quality characteristics. The standing samples would be analyzed for corrosion related parameters.

Running Samples

To document the consistency of water entering the pipe rack, the following parameters were to be collected from the influent water tap after flowing for 30 minutes or more, and immediately prior to shutting off the water flow:

Q Daily• pH• Temperature• Conductivity• Free and Total Chlorine

a Weekly• Alkalinity• Lead• Copper• Dissolved Oxygen• HPC• Coliform

Q Monthly• Calcium • Iron• Ammonia • Zinc• Orthophosphate (as P) • Color• Total P (as P) • Total Dissolved Solids• SiO2

Appendix B.1: Procedures Originally Recommended 279

The parameters listed for monthly evaluation were selected to characterize distribution system water quality. In the event that incoming water quality was highly variable, the frequency of collection was to be increased to weekly.

First Flush Samples

First flush, standing water quality samples (8 hour standing time) were recommended for collection once a week from each of the test loops. The following parameters were to be monitored:

Minimum Recommended Optional

Q Temperature Q CalciumQ pH Q AmmoniaQ Conductivity Q Orthophosphate (as P)Q Alkalinity Q Total P (as P)Q Free and Total Chlorine Q SiO2a Lead Q IronQ Copper Q Zinc

Q Colora TDSQ Dissolved Oxygen

These constituents were selected for analysis as they were considered most likely to change during the standing period. All first flush samples were to be collected with the water continuously flowing from the sampling tap at a slow rate. Since corrosion of pipe materials is responsible for the contamination of drinking water by metals; copper and lead were of major interest in the study. However several other parameters were recommended for monitoring to observe if changes occurred during stagnation due to the corrosion process.

Water temperature, pH, and conductivity were recommended for analysis from the first sample collected from each loop. This assured that the valve had been flushed of any water in direct contact with it, so that following samples for metals levels would have been in direct contact with the test loop material. The metals levels were recommended for analysis on a 1000 mL sample of water from each test loop. Analysis of bacteriological parameters (total coliform and HPC) was suggested for standing samples from each test loop and a running sample from the


influent for several weeks at the beginning of normal test operations. This data was then used to determine if the pipe test sections and sample taps were free from bacterial contamination.

Pipe-Rack Sampling Frequency

The number of pipe rack samples needed to evaluate a correlation between the pipe rack and the distribution system lead levels was determined by evaluating historical pipe loop studies (see Appendix B.2). Low variability waters were defined as having a ratio of mean to standard deviation (for lead levels) of about 1:10, whereas for high variability water, the ratio was about 1:4.

Weekly sample collection was recommended for the pipe rack. This allowed for an estimated accuracy of between 15% to 10% at a confidence interval of 90% for higher alkalinity waters, and better than 10% accuracy at 95% confidence interval for low alkalinity waters. It was felt that collecting samples from the pipe rack would be much easier than the distribution system since the utility participants had complete control over the sampling protocol. In addition, utility personnel would be monitoring the operation of the pipe rack on a regular basis, and weekly sample collection would fold easily into that schedule.

DISTRIBUTION SYSTEM MONITORING GUIDELINES

Data collected at the consumers' taps was to be correlated to data from the pipe rack, therefore, it was important to generate enough data to be statistically significant as well as to standardize the protocol for site selection and collection of samples. For each pipe rack built for the distribution system correlation studies, it was recommended that each utility identify a target population (customer services) within the distribution system. The following discussion presents:

Q Definition of target population (services) and selection of households,Q Recommendations for number of households to sample,Q Frequency of sample collection,Q Procedures for collecting samples, andQ Data reporting items.


Selecting Households to Monitor

The protocol for selecting households to monitor was based on best estimates of what the Final Lead and Copper Rule would contain as well as the statistical requirements for correlating the distribution system data with data from a pipe rack.

The target population is the number of services in an area or cross-section of a service area where there are worst case homes with respect to elevated lead levels. Worst case homes were defined as houses with copper plumbing with 50-50 tin-lead solder installed after 1983 or houses with lead service lines. In order to correlate the pipe rack data to distribution system data, the target population (services) were to:

1. receive the same water which flows through the pipe rack, and2. contain piping materials which was similar to the pipe rack.

For example, utilities where soldered copper plumbing in the home may be the largest contributor of lead levels at the tap, would evaluate soldered copper in their pipe rack. In that instance, the target population for distribution system sampling were houses (services) with 50- 50 tin-lead solder which were installed after January 1983. The actual houses (taps) for sampling would be selected from within this target population. For utilities evaluating lead pipe in their pipe rack, the target population would be houses (services) with lead service lines. Also, non- residential sites with the same piping criteria may be used if no houses can be found that fulfill the criteria. These non-residential sites should have water use patterns and plumbing configurations similar to the residential sites. If the utility was still unable to find enough sites, single family houses with 50-50 tin-lead solder installed before 1983 could be used. Each utility participating in the distribution system correlation study portion of the project had to define their "target population" based on an understanding of their service area and where there was a potential for elevated lead levels.

Recommended Number of Households for Tap Sampling

Table B.I displays the number of houses which would need to be sampled based on the target population for each pipe rack. For example, if a utility was to correlate pipe rack data with a target population (number of customer services) of 5000 houses which have 50-50 lead-tin solder less than 5 years old, at an accuracy of 15% and a confidence level of 90%, 117 out of the 5000 households would need to be sampled.


The recommended number of households to be sampled by each utility was based on achieving a 20% accuracy and 90% confidence level in the data. This amounts to 66 households for a target population of 5000 and 67 for larger target populations. In addition, it was recommended that each utility collect samples from approximately 20% more households than required, in the event that some households drop out of the program. This would amount to a total of 79 houses for target populations of 5000 or 80 houses for target populations greater than 5000. Trying to achieve better accuracy in the data significantly increases the number of households which must be sampled, as seen in Table B.I.

Frequency of Sample Collection

In order to correlate distribution system and pipe rack data, it was critical to determine a specific evaluation period. The number of observations necessary for various accuracy and confidence levels would then apply to the particular period of evaluation chosen. For example, if a quarterly evaluation period was chosen, then 67 sites (80 assuming an extra 20%) in the distribution system would need to be sampled quarterly to achieve a 20% accuracy and 90% confidence level in the data. For a monthly evaluation period, 80 sites would need to be sampled each month.

This project was designed to evaluate pipe rack data collected over a one year period and a one month period of evaluation was recommended. This allowed seasonal trends as well as potential fluctuations in water quality to be evaluated. Samples would be collected from each of the distribution sites once a month. This frequency allowed overall system means to be evaluated. It did not, however, take into account any within site variability. To evaluate within site variability, the frequency of sample collection would be significantly higher (4-5 times a week).

A two month evaluation period was also recommend to the utilities, however fewer data points would then be available for determining system means. Using evaluation periods longer than 2 months (i.e. collecting samples quarterly) risked losing the potential for detecting seasonal variations, since samples would be collected throughout the 3 month period when temperature and other environmental conditions could vary significantly.

Household Tap Sampling Procedures

For this study the following household sampling protocol was recommended:


1. For utilities building a soldered copper pipe rack:Q Samples should be collected at the kitchen's cold water tap after standing a

minimum of 8 hours. Q Two sets of samples should be taken: a first draw 250 mL sample

followed immediately by a 750 mL sample.2. For utilities building lead test loops in their pipe rack:

Q One 1 Liter sample should be collected using either one of two different collection protocols. Samples can be collected after a 8 hour standing time (listed in order of preference):• At a tap made on or near the service line itself, or• At the cold kitchen tap after flushing until the calculated volume

contained in the home plumbing has been discharged.3. The plumbing system should be thoroughly flushed out the night before.4. Fully flushed samples should be collected at a small number of sites (6),

preferably the night before, or after the standing samples are collected.

Parameters to be Analyzed

At a minimum, the following parameters were recommended for analysis on first flush tap samples:

Q Total Lead (both the 250 mL and 750 mL sample)Q Total Copper (both the 250 mL and 750 mL sample)Q Field pH (if utility personnel are collecting the samples - on either sample)

For utilities interested in corrosion rate evaluations and general corrosion parameters, the following parameters were recommended for collection at the tap in addition to the lead and copper:

a Iron (both the 250 mL and 750 mL sample)Q Zinc (both the 250 mL and 750 mL sample)G Cadmium (both the 250 mL and 750 mL sample)Q Conductivity (on either sample)Q Temperature (on either sample)G Alkalinity (on either sample)


For distribution system water quality samples (fully flushed samples), the following parameters were recommended for analyses once a month from the distribution system to provide background information: (the influent to the pipe-rack could be used as a distribution site)

pHAlkalinityTemperatureConductivityDissolved OxygenFree and Total ChlorineCalciumOrthophosphate as PTurbidity

a LeadQ CopperQ AmmoniaQ Zinca TDSa THMs and other DBFsQ Colora Irona Si02a Total P (as P)

Appendix B.1: Procedures Originally Recommended 285

Table B.I

Number of distribution system sample sites (services)per evaluation period for various target populations,

accuracy, and confidence intervals

Tareet Peculation5,000

AccuracyLevel

25%20%15%10%

C.I.*90%

4366117255

95%

6398172370

10,000C

90%

4367118262

.1*

95%

6499175385

20,000C.I.*

90%

4367119265

95%

64100176392

50,000C.I.*

90%

4367119268

95%

64100177397

100,000C.

90%

4367119268

I.*

95%

64100177398

* C.I. = Confidence Interval

Appendix B.2

Original Sample Program Design

The three most important factors in determining the number of samples needed (i.e. "sample population" size) are:

1. The required accuracy,2. The required confidence level, and3. The expected variability.

For the distribution system correlation portion of this study, a targeted population referred to a group of services (houses) for which lead levels were to be estimated. Within this population, a smaller number of services constituted the "sample population" from which actual lead levels were measured.

Statisticians use two parameters, accuracy and confidence level, when defining how reliable the sample mean from a sample population is. Sample reliability depends on the required accuracy level and desired confidence level. As the desired accuracy and confidence level increase, the "sample population" size will increase. Accuracy can be expressed as a band around the sample mean, within which the true mean is expected to fall. This band is normally thought of as a percentage from the mean. Typical sample accuracy ranges from 1 to 20 percent. For example, data from a sample population that is 10 percent accurate, has a band around it with an upper bound of the sample mean plus 10 percent and a lower bound of the sample mean minus 10 percent. A sample population designed for 10 percent accuracy with a sample mean of 0.02 mg/L implies that the true mean lies within the range of 0.018 mg/L and 0.022 mg/L.

Accuracy is coupled with how confident we are of the sample population we've chosen, i.e. is the sample population truly representative of the target population. Confidence levels are presented in terms of the percent of time the results gathered are expected to be true. Typical

287


confidence levels range from 60 percent to 99 percent. For example, a 95 percent confidence level for a 10 percent accuracy level means that we expect data from the sample population to produce values within 10 percent of the true mean 95 percent of the time.

Another factor which affects the necessary sample population size is the expected variability of lead levels among the targeted population. The greater the variability, the larger the sample population size needs to be to produce statistically reliable results. In this study, variability referred to the coefficient of variation. This is measured as a ratio of the standard deviation divided by the mean:

Coefficient of Variation = Standard DeviationMean

The variability has a large effect on sample population size and reliability. To estimate the number of lead samples and frequency of collection required to obtain statistically significant results for this study, the variability of historical data was assessed. This data included both lead levels measured from the tap and from pipe rack studies. The estimates on number and frequency of sampling described below were intended to be a starting point for utilities in refining the coefficient of variation for their particular situation.

Based on historical tap lead level studies, the expected variability for homes with lead soldered copper piping or lead service lines was estimated to be 1:1 (Karalekas 1984). The numbers of households which would need to be sampled based on a 1:1 ratio of standard deviation/mean, are presented in Table B.I (Appendix B.I) for various accuracy and confidence levels and different target populations. The number of households which need to be sampled to achieve the required accuracy and confidence levels increases dramatically as the accuracy narrows from 25% to 10%. There is also an increase in sample sizes when the confidence level is reduced from 90% to 95%. This makes intuitive sense since a much larger number of samples is required to be 95% confident that the true mean lead level is within plus or minus 10% of the sample mean vs a smaller number of required samples to be 90% confident that the true mean falls within 25% of the sample mean. The number of required sampling sites changes only slightly as the target population is increased however; i.e. for an accuracy of 15% and confidence interval of 90%, the required number of households for target populations of 5,000 and 100,000 are 117 and 119 respectively.

To evaluate the potential variability in lead levels measured from a pipe rack, studies by USEPA and AWWARF were evaluated (Schock 1980, Schock and Gardels 1983, AWWARF 1990). The USEPA study, which used lead pipe, suggested that for very low alkalinity waters the ratio of standard deviation to the mean was about 1:10. For slightly higher alkalinity waters,

Appendix B2: Original Sample Program Design 289

(> 18 mg/L CaCO3), the ratio was about 1:4. The initialAWWARF pipe rack studies were conducted for only one month, however the ratio of standard deviation to the mean was approximately 1:10 for lead pipe and 1:7 for soldered copper pipe. Consequently, the range of variability used for pipe rack data in this study was defined as follows:

VariabilityCategory (Std. Dev/Mean)

Low Variability 1:10 High Variability 1:4

For this study, a pipe rack was defined as one assembly in which multiple loops of various materials could be evaluated. The pipe rack refers to the complete unit, which includes the inlet, outlet, manifold, valves, replicate flow through loops, connecting piping, etc. The number of observations required from a pipe rack at various accuracy and confidence intervals, assuming a 1:10 and a 1:4 variability, are listed in Table B.2. For waters exhibiting lower variability, fewer samples would be required. Using an evaluation period of one month, a pipe rack with three replicate loops would need to be sampled once a month to achieve a 10% accuracy and 90% confidence level in the data (assuming low variability). One sample round is equivalent to 3 observations, i.e. one sample is drawn from each of the three replicate loops. By comparison, 17 observations would be needed to achieve the same accuracy and confidence level for waters exhibiting high variability. For a pipe rack with three replicate loops, this would involve 17/3 sampling rounds or collecting samples, approximately 6 times per month.

The possibility of increasing the number of replicate loops within the pipe rack and the corresponding impact on the frequency of collecting samples was also evaluated. Table B.3 displays the number of times a month in which samples would need to be collected at various accuracy and confidence levels assuming different numbers of replicate loops within a pipe-rack. For low variability waters (1:10) once a month sampling from a pipe-rack with three replicate loops is adequate to meet a 10% accuracy and 90% confidence interval. For high variability waters (1:4), samples would need to be collected approximately 6 times a month from a piperack with three replicate loops vs approximately 4 times for a pipe-rack with 5 replicate loops. Increasing the number of replicate loops in the pipe-rack from 3 to 5 does not significantly reduce the number of sample collections which would be needed in a month. Bi-weekly or weekly sample collection from a pipe-rack with 3 replicate loops appears to be adequate to meet an accuracy level between 15% and 10% for both low and high variability waters. This level of accuracy will undoubtedly be higher than what could feasibly be achieved in the distribution system samples.


With respect to the distribution samples, once a month sample collection each of the sites was assumed to be adequate to determine overall system mean lead levels. This did not take into account the within site variability however. In order to evaluate site by site variability, the same households would need to be sampled once every 4 days, which would be an extremely burdensome monitoring program.

Appendix B2: Original Sample Program Design 291

Table B.2

Number of observations per evaluation period for pipe-rig monitoring at various accuracy and confidence levels*

Standard deviation/mean

Accuracy Level

25%20%15%10%

(1:10)90%

<1113

C.I.95%

1124

90%

347

17

fl^CJ.95%

46

1125

* 1 observation = 1 sample from one of the replicate loops in the pipe rack.


Table B.3

Number of times to sample each pipe rack in a month*

(1:10 variability 1:4 variability) Number of C.L/accuracv ___C.I./accuracv

replicate loops

12345

90/10

32111

95/10

42211

90/10

179654

95/10

2513975

* Rounded to the next highest whole number - each sample time involves collecting one sample from each of the replicate loops, i.e. 2 sampling times per month with three replicate loops equals six total samples for that month.

Appendix C

Statistical Background

Appendix B contained recommendations on distribution system and pipe rack sampling which were used as a starting point for assessing data variability in this study. The following Appendix provides information on estimating the number and frequency of sample collection for a corrosion study, as well as determining the confidence and accuracy of the data after it has been generated. This discussion is followed by a reprint of a paper entitled "Statistical Procedures for Corrosion Studies," presented at the AWWA Water Quality Technology Conference in Toronto, Ontario, November 15 - 19, 1992. This paper provides additional guidance on the statistical background and data evaluation techniques applicable to corrosion studies.

ESTIMATING SAMPLE SIZE

The most familiar formula for determining sample size is based on an assumption that the data is normally distributed. Results of this study indicate that metals level data from pipe rack studies usually exhibit either a non-normal distribution, or in cases where there are very few data points, an unknown distribution. Formulas for determining sample size based on non-normal distributions can be generated, however when sample sizes are large, the central limit theory applies. This theory states that the distribution of the difference between two sample means is at least approximately normally distributed. Therefore, when evaluating probabilities associated with the values of a specific test statistic, the procedures would be the same as if the population itself were normally distributed. The definition of what constitutes a 'large' sample size varies. Statistical texts have stated that sample sizes greater than 30 would be considered large enough to apply the central limit theory and assume normality. In several of the recently completed pipe rack studies, the total number of samples collected for standing lead and copper levels were

295


greater than 30 and usually greater than 100. For this reason, the formula for determining sample size discussed below is based on an assumption of normality.

If the variability of a sample population is known, an estimate of the required sample number can be made using the following formula:

n = (zs/Bx)2) or n = (z/B)2(s/x)2 where: n = number of samples

z = critical region of the normal distribution, which depends on the significance level of the test, i.e. z = 1.96 for a 95% significance level and z = 1.645 for a 90% significance level

B = the bound, or accuracy of the estimated mean level, i.e. if B = .10, the estimate of u would fall within_± 10%ofx.

s = standard deviation of the sample population x = the average of the sample population

Examples of Sample Size Estimation

Initial estimates of sample frequency should be based on an understanding of the inherent variability of lead or copper levels measured from pipe loop studies. This will insure that the number of samples collected will provide statistically significant results. The coefficient of variation is the ratio of the standard deviation over the mean (s/x), and is a measure of the variability in the data. Table C.I lists several required sample sizes for the range of coefficients of variation typically found in pipe rack studies, for various confidence intervals and accuracy. This table can be used to determine initial sample frequencies for pipe rack studies.

The frequency of sample collection may be reduced as the study progresses if the variability of the data is lowered. However, seasonal water quality changes may impact the lead and copper levels measured during a pipe loop study. Maintaining a conservative estimate of the required sample size throughout the study period may be most appropriate. Once the data has been generated from a pipeloop study, it is desirable to determine the confidence and accuracy of the sample. This information allows for more specific evaluation of the reliability of the differences measured between a control and treated loop. Using the same equation for estimating sample size, but solving for (z/B), the actual confidence and accuracy of the data generated can be calculated.

Appendix C: Statistical Background 295

Table C.I

Estimated sample size for various confidence intervals and accuracy levels

Coefficient of variation1:3 CI 1:2 CI 1:1.25 CI MCI 1:0.7 CI 1:0.5 CI

__________90% 95% 90% 95% 90% 95% 90% 95% 90% 95%__________Accuracy Level

25% 40 44 62 85 121 174 246

20% 44 62 68 97 133 189 271 385

15% 30 43 77 110 121 171 236 335 482 683

10% 35 68 97 174 246 271 385 531 753 1093 1537

Appendix D__________

Public Information Items and Materials for Implementing Home Tap Monitoring, Fort Worth Water Department

297


Date

News Person Address

Dear News Person:

Lead in the environment is a concern all of us share, and the Fort Worth Water Department is exploring the issue of lead and drinking water.

The department is attacking the issue on two fronts:• By taking advantage of the opportunity to be one of just five cities

nationwide to participate in a study on how plumbing affects the lead and copper content of drinking water. Residents in two neighborhoods, Como and Hulen Meadows, may participate in the study. In exchange, they will leam if there is a problem with the lead or copper content of their own drinking water at no charge. We are now recruiting people to participate in this study.

• By educating the public That includes media awareness as well as working with physicians, day-care workers and others who communicate with members of the two high-risk groups for lead exposure-pregnant women and children.

Inside is a news release concerning the study, a fact sheet on lead and drinking water, a brochure and a copy of the application form residents may request if they want the department to test the lead content of their water. A drawing depicts the model "plumbing loops" that have been built inside the Como and Alta Mesa pump stations as part of the research study.

Also inside is a small piece of lead pipe. This pipe is one portion of a lead pipe removed from the Como neighborhood. Some homes in this area have a pipe like this one connecting their water meter with the main water pipe in the street

If you decide to pursue this story and would like to visit or shoot the model plumbing loops installed in the pump stations, let me know. These locations are locked and I will need to meet you there.

I hope you have an opportunity to help us share this information. Should you have any questions or need anything else, please call me at 871-8208; Richard Talley, Laboratory Services manager, at 572-3154; or Linda Nelson, assistant director/Production, at 871-8293-

Sincerely,

Cari HydenPublic Education SpecialistEnclosures

Appendix D: Public Information Materials 299

Upon ReceiptCari Hyden, public education specialist, 871-8208; Richard Talley, LaboratoryServices manager, 572-3154; or Linda Nelson, assistant director, 871-8293.

Residents may participate in first-of-a-kind, national/ study of lead and copper in drinking water

The Fort Worth Water Department is one of just five utilities nationwide selected to participate in a study on the effect private plumbing has on drinking water quality—the first conducted in this city.

The Water Department is teaming with the American Water Works Association Research Foundation to explore any correlations between residential plumbing and the lead and copper content in drinking water.

One hundred residents each in the Como and Hulen Meadows neighborhoods have an opportunity to participate in the study, and, as a side benefit, learn if there is a problem with the lead or copper content of then- own drinking water at no charge.

The study targets these neighborhoods because research has shown the homes most likely to have high levels of lead or copper in their drinking water most often are less than five years old or more than 50 years old. Homes more than 50 years old may have lead plumbing, or the small pipe that connects their water meter to the large water main in the street may be made of lead. Homes less than five years old have new plumbing, and the minerals in Fort Worth's water have not yet had a chance to coat the inside of the pipes.

The study is expected to help determine whether the city has a problem with its water picking up metals from plumbing. In addition, it will help utilities determine the best way to monitor the effect private plumbing has on water quality.

To determine this, small model "plumbing loops" have been built inside the Como and Alta Mesa pump stations. Water samples will be taken from these plumbing loops each month, and the lead and copper content from the plumbing loop samples will be compared with samples taken from homes in the area.


It is hoped samples from the plumbing loop and those from the homes will have similar test results. If they do, water utilities will be able to monitor the lead and copper content in the water from these model plumbing loops, rather than having to bother residents by testing inside their homes.

The study will begin this summer and last for one year. Residents of the Como and Hulen Meadows areas who wish to participate may contact the Fort Worth Water Department Laboratory Services at 572-3154.

Unfortunately, the study must be limited to those two neighborhoods. The homes eligible in the Como area are south of White Settlement Road and north of Westpoint Boulevard, between Chapel Creek Boulevard to the west and Academy Boulevard to the east Eligible homes in the Hulen Meadows area are south of Columbus Trail between West Cleburne Road to the west and McCart street to the east

However, all residents who wish to have their water analyzed for lead contact may contact the laboratory and request an application form. Cost for this service is $12. Those who participate in the study will have this analysis performed at no charge.

The department has not had trouble with lead in its water sources. Any lead or copper that appears in residents' drinking water most likely would derive from their own plumbing.

The department consistently has produced water that not only meets all governmental standards, but is even better than required. However, this study will generate reliable information to determine the effect residential plumbing has on water quality.

The other water utilities participating are the Philadelphia Water Department, New York City water utilities, the Contra Costa Water Department in Contra Costa, Calif., and the Portland Water Bureau in Portland, Ore.

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Facts about lead and drinking water

Residents may not realize their private plumbing may have an effect on their water quality.

The Fort Worth Water Department recognizes this and wants to educate the public about which households may be at risk and the simple, self-help measures available to reduce those risks.

The risks In Fort Worth are less than those for other parts of the United states for these reasons:

• Lead does not occur naturally in Fort Worth Water. Even if it did/ it would be easy to remove at the water treatment plants.

• Fort Worth waters generally are more alkaline than acidic, and usually are not at risk for leaching metals from plumbing.

• The Water Department treats the water so it remains alkaline, and so that, over time, it will actually coat pipes with a mineral coating and prevent water from coming in contact with metal plumbing.

However, the department still wants to be certain residents know the potential hazards involved and can protect themselves.

Homes most likely to develop problems with lead exposure are:• Those older than 50 years old. These homes may have lead plumbing

or have lead "service connectors," the small pipe that connects the water meter with the main water pipe in the street

• Homes less than 5 years old with non-plastic plumbing. These homes may have lead solder joining the pipes. The water hasn't yet had a chance to coat the inside of the pipes with minerals in newer homes, and the water may come in contact with the metals.

Residents who live In high-risk homes may follow these steps to reduce their possible lead exposure:

• If it has been several hours since water was drawn from a faucet, let the water run a few minutes until it gets as cold as it will get before consuming it. Water that has been stored in the pipe for several hours is more likely to have higher lead levels. Use the water to water plants, wash dishes or for other non-consumption purposes.

• Never drink or cook with hot tap water-always heat the water on the stove. Hot water from the tap also is more likely to have high lead levels.

• Make sure your plumber uses only lead-free solder when making repairs.

• If you live in a new home, check the faucet screens for the first few months until all small debris is flushed from the system.

This may be all the protection many residents need.

Residents should be suspicious of their plumbing If:• Their home has pipes that are dull gray metal that is soft enough to

be easily scratched with a key. These pipes may be made of lead.


• If they see signs of corrosion—frequent leaks, rust-colored water, stained dishes or laundry.

• If their non-plastic plumbing is less than five years old.• If the household includes a pregnant woman or a child less than 7

years old, those most at risk for lead exposure. The body mass of children and developing fetuses are small, and absorb more lead per pound than adults.

If residents believe their plumbing may be at risk, they may follow the self-help measures listed above, and they may wish to have their water tested.

Private labs that perform this service are listed in the Yellow Pages under "Laboratories—Analytical." In addition, the Fort Worth Water Department is now offering lead testing in its laboratory for $12. Those interested should call 572-3154 and request a lead testing application. Results will be available two to three weeks after a member of the laboratory staff takes a water sample.

Lead cannot be removed by most home water filtering systems. Only those systems that use reverse osmosis will remove lead.

The Fort Worth Water Department Is minimizing the risk of lead exposure by:

• Taking advantage of an opportunity to participate in a national study on the effect plumbing has on lead and copper content in drinking water.

• Making sure the water is more alkaline, not acidic, so that instead of leaching metals from the pipes as it flows through them, the water deposits minerals onto the pipes and develops a protective coating.

• Teaching day-care workers to be aware of lead and its risks to children.

• Encouraging physicians to help educate their patients.• Continuing an ongoing program to remove any lead service pipes

still in use.•Educating the public.

Those who want more Information about lead and drinking water:• May call 871-8284 and leave their name an address for a free brochure.• Obstetricians, gynecologists, pediatricians and family practice

physicians who wish a supply of brochures to make available to patients who may be at risk should write or call Public Education, Fort Worth Water Department, P.O. Box 870, Fort Worth, TX 76101,871-8220.


Sample of lead pipe

Attached is a portion of a lead "service connector," the small pipe that connects a resident's water meter to the main water pipe in the street. This one was removed from the Como neighborhood.

Lead is a soft, gray metal that scratches easily. You will notice that you can easily gouge this pipe with a key. That's one way residents can determine if they have lead plumbing.

If you look inside the pipe, you can see that Fort Worth's alkaline water has deposited minerals inside it. These are the same minerals you might see settle to the bottom of your tea kettle. These minerals provide a protective coating that prevents water from coming in direct contact with the metal.


HOW DO YOUR

PIPESAFFECT YOUR

WATERQUALITY

Your chance to participate in a national study

Sponsored locally by the Fort Worth Water Department

Determining how private plumbing affects your water quality

The Fort Worth Water Department wants to know how residents' private plumbing affects their water quality.

Studies have shown that water some times can pick up small quantities of certain metals from the plumbing. In rare cases, the water could pick up enough of the metal that it would affect a person's health if consumed

Two metals that most commonly are dissolved from plumbing are lead and copper.

The Fort Worth Water Department already takes steps to reduce the chance water picks up metals from private plumb ing. Fort Worth water is treated so it is slightly alkaline, rather than acidic. Acidic waters are more likely to dissolve metals from plumbing. Alkaline waters actually deposit minerals inside the pipes, forming a protective coating that prevents water from coming in direct contact with the metals. You may have noticed these min erals forming inside your tea kettle.

However, despite these precautions, the department wants to make sure Fort Worth residents don't have to worry about lead or copper in their drinking water.

National study under wayRecently, the Water Department was

offered the opportunity to participate in an


important national study on lead and copper in drinking water. The study is funded by the American Water Works Association Research Foundation, and the Environmental Protection Agency will participate as a review committee member.

Two Fort Worth neighborhoods will be targeted in this study. They are:

Como area—The Como area was se lected because many of the homes were built before 1940, and they may still have small, lead pipes connecting the water meters to the main pipe in the street.

Alta Mesa area—This area was selected because many of the homes are less than five years old. The water may not yet have had a chance to coat the inside of the pipes in these homes, so water may come in direct contact with the metal plumbing.

You can benefitThe department needs 100 homes from

each neighborhood to participate. Partici pants will learn—free of charge—if they have a problem with lead or copper con tent in their drinking water.

If you choose to participate, you will be given a survey to fill out. A representative from the Water Department's Laboratory Services division will be available to help you, if needed.

You will be asked to collect one water sample each month in special containers that will be provided. You will be told which day each month to collect your

sample. Samples will be placed outside your front door, and a Water Department representative will collect it. Monthly samples will be collected for one year.

The samples will be analyzed, and if anything out of the ordinary is detected, you will be notified.

Sample results to be comparedResults of the residential water samples

will be compared with water samples collected from specially constructed "model" plumbing systems. One will be built in the Como Pump Station, and one at the Alta Mesa Pump Station. The Water Department hopes to find out if the water's affect on private plumbing can be determined from one of these "model" plumbing systems, or if it is necessary to test water in each person's home.

Can you help?As you can see, this is an important

study. We hope you will join us. Not only will you learn the lead and copper content of your own water, but you will be con tributing to research that could benefit people throughout the world.

If you would like to participate, please fill out the attached form. A Laboratory Services chemist or microbiologist will be back in touch to arrange the details.

Thank you for helping us provide you with the best possible water.


Important Water Department telephone numbers:

Laboratory Services.................. 572-3154(water quality questions)

Water Quality Hotline ............... 871-8284(for a recorded message on water quality)

Customer Service...................... 871-8210(questions about bills)

Water, sewer emergencies....... 871-8300(main breaks, stopped sewers,

leaking fire hydrants)

Meter shop................................ 871-8294(water running in the meter box, meter not

working, water needs to be turned offat the street)

Garbage collection.................... 871-5150

Fort Worth Water Department1000 Throckmorton • P.O. Box 870

Fort Worth, TX 76101(817) 871-8220

•I

City

of F

ort W

orth

Wat

er D

epar

tmen

t W

ater

Qua

lity

Sam

plin

g Pr

ogra

m

Yes

, I w

ant t

o pa

rtic

ipat

e in

this

stud

y. I

und

erst

and

that

if d

efic

ienc

ies a

re d

iscov

ered

in m

y pl

umbi

ng, i

t w

ill b

e m

y ow

n re

spon

sibili

ty t

o m

ake

the

repa

irs a

nd t

hat

the

City

of

Fort

Wor

th

bear

s no

res

pons

ibili

ty fo

r m

y pr

ivat

e pl

umbi

ng.

Nam

e —

——

——

——

——

——

——

——

——

——

——

——

——

——

——

——

——

——

Dat

e

Add

ress

Fort

Wor

th, T

exas

Zi

p C

ode

______________ P

hone

If y

ou h

ave

any

ques

tions

, ple

ase

cont

act t

he W

ater

Dep

artm

ent's

Lab

orat

ory

Serv

ices

Div

isio

n at

57

2-31

54. T

hank

you

for

your

will

ingn

ess

to p

artic

ipat

e in

this

stud

y.

Intro

duct

ion

iTh

e fo

cus

on le

ad in

dr

inki

ng w

ater

ste

ms

from

su

cces

s at

redu

cing

the

pres

ence

of l

ead

in o

ther

ar

eas.

Our

tota

l lea

d ex

po

sure

is m

uch

low

er th

an it

w

as a

dec

ade

ago

due

to

bans

on

lead

-bas

ed p

aint

, th

e re

mov

al o

f lea

d fro

m

gaso

line

and

prog

ress

in

elim

inat

ing

lead

sol

der f

rom

fo

od c

ans.

The

focu

s is

now

on

redu

cing

pot

entia

l

cont

amin

atio

n of

drin

king

w

ater

by

lead

.Fo

rt W

orth

wat

er d

oesn

't co

ntai

n le

ad. H

owev

er, l

ead

coul

d ap

pear

in y

our w

ater

as

the

resu

lt of

lead

pip

es o

r le

ad s

olde

r in

your

hom

e's

plum

bing

. Th

e im

porta

nt

thin

g to

rem

embe

r is

ther

e ar

e se

vera

l sim

ple

mea

sure

s yo

u ca

n ta

ke to

redu

ce th

e ch

ance

of e

xpos

ure.

Sour

ces

of L

ead

Con

tam

inat

ion

Lead

rare

ly o

ccur

s na

tual

ly in

drin

king

wat

er. I

t ty

pica

lly g

ets

into

drin

king

w

ater

afte

r it h

as le

ft th

e w

ater

trea

tmen

t fac

ility.

O

nce

wat

er le

aves

the

dist

ribut

ion

syst

em a

nd

ente

rs h

ome

plum

bing

, the

w

ater

sup

plie

r doe

sn't

have

fu

ll co

ntro

l of

the

end

prod

uct.

If yo

u ha

ve u

nsaf

e le

vels

of

lead

in y

our d

rinki

ng

wat

er, t

he s

ourc

e is

mos

t of

ten

lead

pip

es o

r sol

der (

a m

etal

lic c

ompo

und

used

to

seal

join

ts b

etw

een

pipe

s)

on y

our o

wn

plum

bing

.

• The

mos

t com

mon

ca

use

is co

rrosi

on, a

reac

tio

n be

twee

n th

e w

ater

and

th

e le

ad p

ipes

or s

olde

r. Th

e W

ater

Dep

artm

ent t

reat

s w

ater

so

it is

"har

der"

and

not

co

rrosi

ve, a

nd it

will

actu

ally

he

lp c

oat p

ipes

with

a

min

eral

dep

osit

as it

pas

ses

thro

ugh

them

. Sof

t wat

er

(whi

ch la

ther

s so

ap e

asily

) is

mor

e co

rrosi

ve. S

oft o

r aci

dic

wat

er c

orro

des

plum

bing

by

leac

hing

out

lead

.

• Ano

ther

fact

or th

at

incr

ease

s co

rrosi

on is

the

prac

tice

of g

roun

ding

el

ectri

cal e

quip

men

t (su

ch

as te

leph

ones

) to

wat

er

pipe

s. A

ny e

lect

ric c

urre

nt

trave

lling

thro

ugh

the

grou

nd w

ire w

ill ac

cele

rate

th

e co

rrosi

on o

f lea

d in

the

pipe

s. N

ever

thel

ess,

wire

s sh

ould

not

be

rem

oved

from

pi

pes

unle

ss a

qua

lifie

d el

ectri

cian

inst

alls

an

adeq

uate

alte

rnat

ive

grou

ndin

g sy

stem

.•

Lead

-con

tam

inat

ed

drin

king

wat

er is

ofte

n a

prob

lem

in h

ouse

s th

at a

re

eith

er o

lder

than

50

year

s or

ne

wer

than

five

yea

rs. O

lder

ho

mes

are

affe

cted

bec

ause

up

thro

ugh

the

1930

s, it

was

co

mm

on in

som

e ar

eas

of

the

coun

try to

use

lead

pi

pes

for i

nter

ior p

lum

bing

. Le

ad p

ipin

g w

as o

ften

used

fo

r ser

vice

con

nect

ions

that

jo

in th

e w

ater

mai

n to

the

hous

e. T

his

prac

tice

ende

d du

ring

the

1940

s in

For

t W

orth

. Plu

mbi

ng in

stal

led

befo

re 1

930

is m

ost l

ikel

y to

co

ntai

n le

ad. C

oppe

r pip

es

have

repl

aced

lead

pip

es in

m

ost r

esid

entia

l plu

mbi

ng,

but t

he u

se o

f lea

d so

lder

w

ith c

oppe

r pip

es w

as

wid

espr

ead

prio

r to

the

ban

on le

ad s

olde

r pas

sed

in

a -o

1988

. Exp

erts

rega

rd le

ad

sold

er a

s th

e m

ajor

cau

se o

f le

ad c

onta

min

atio

n of

ho

useh

old

wat

er.

Scie

ntifi

c da

ta in

dica

tes

that

new

er h

omes

car

ry a

gr

eate

r ris

k of

lead

con

tam

i na

tion.

Lea

d le

vels

de

crea

se a

s a

build

ing

ages

. As

tim

e pa

sses

, min

eral

de

posi

ts fo

rm a

coa

ting

on

the

insi

de o

f pip

es (i

f the

w

ater

is n

ot to

o co

rrosi

ve).

This

coa

ting

insu

late

s th

e w

ater

from

the

sold

er. B

ut,

durin

g th

e fir

st fi

ve y

ears

(b

efor

e th

e co

atin

g fo

rms)

w

ater

is in

dire

ct c

onta

ct

with

the

lead

. Wat

er in

bu

ildin

gs le

ss th

an fi

ve

year

s ol

d is

mor

e su

scep

tib

le to

hig

h le

vels

of l

ead.

Lead

- co

nta

min

ated

d

rin

kin

g w

ater

is

oft

en a

p

rob

lem

in

hous

es t

hat

ar

e o

lder

tha

n 50

yea

rs.

Plu

mbi

ng

inst

alle

d in

ho

mes

bef

ore

19

30 is

mos

t lik

ely

to

con

tain

lea

d.

Hea

lth R

isks

of L

ead

Sim

ple

Prec

autio

ns fo

r R

educ

ing

Lead

Exp

osur

eCh

ildre

n an

d pr

egna

nt

wom

en a

re at

gre

ates

t ris

k fro

m e

xpos

ure

to le

ad.

Lead

is p

artic

ular

ly

harm

ful t

o th

e de

velo

ping

br

ain

and

nerv

ous

syst

em.

Chi

ldre

n un

der s

even

yea

rs

of a

ge a

re p

artic

ular

ly

vuln

erab

le b

ecau

se th

eir

nerv

ous

syst

ems

are

still

deve

lopi

ng.a

nd b

ecau

se

thei

r bod

y m

ass

is sm

all,

they

inge

st a

nd a

bsor

b m

ore

lead

per

pou

nd th

an a

dults

. R

ecen

t stu

dies

sho

w th

at

low

-leve

l exp

osur

e to

lead

at

a yo

ung

age

can

caus

e pe

rman

ent l

earn

ing

disa

bili

ties

and

hype

ract

ive

beha

v io

r. Pr

egna

nt w

omen

can

tra

nsm

it le

ad e

xpos

ure

to

thei

r dev

elop

ing

fetu

s,

caus

ing

prem

atur

e bi

rth a

nd

low

birt

h w

eigh

t.

Det

ectin

g th

e Pr

esen

ce

of L

ead

Be p

artic

ular

ly s

uspi

ci

ous

if you

r hom

e ha

s le

ad

pipe

s (le

ad is

a d

ull-g

ray

met

al th

at is

sof

t eno

ugh

to

be e

asily

scr

atch

ed w

ith a

ke

y), i

f you

see

sig

ns o

f co

rrosi

on (f

requ

ent l

eaks

, ru

st-c

olor

ed w

ater

, sta

ined

di

shes

or l

aund

ry),

or if

you

r no

n-pl

astic

plu

mbi

ng is

less

th

an fi

ve y

ears

old

.It'

s a

good

idea

to h

ave

your

hou

seho

ld te

sted

for

lead

if y

ou d

etec

t any

of

thes

e su

spic

ious

sym

ptom

s,

or if

you

r hou

seho

ld in

clud

es

child

ren

or a

pre

gnan

t w

oman

. Tes

ting

is al

so

impo

rtant

for a

partm

ent

dwel

lers

, bec

ause

flus

hing

m

ay n

ot b

e ef

fect

ive

in hi

gh-

rise

build

ings

. Bec

ause

you

ca

nnot

see

, tas

te o

r sm

ell

lead

dis

solv

ed in

wat

er,

test

ing

is th

e on

ly s

ure

way

of

tellin

g if

harm

ful q

uant

ities

ar

e pr

esen

t tha

t vio

late

go

vern

men

tal s

tand

ards

. W

ater

sam

ples

from

the

tap

can

be c

olle

cted

and

sen

t to

a qu

alifi

ed la

bora

tory

for

anal

ysis

.The

For

t Wor

th

Wat

er D

epar

tmen

t Lab

ora

tory

Ser

vice

s D

ivis

ion

cond

ucts

lead

test

ing

for a

$1

2fee

. Cal

l572

-315

4for

m

ore

info

rmat

ion.

Fortu

nate

ly, i

t's e

asy

to

prot

ect y

ours

elf a

gain

st le

ad

expo

sure

. The

re a

re s

ever

al

sim

ple

thin

gs y

ou c

an d

o to

m

inim

ize

your

exp

osur

e to

lead

.• D

on't

drin

k th

e fir

st

wat

er o

ut o

f you

r tap

in th

e m

orni

ng. W

ater

that

sits

in

your

pip

es o

vern

ight

or f

or

long

er th

an s

ix h

ours

can

ac

cum

ulat

e le

ad. F

irst,

"flus

h" th

e co

ld w

ater

fauc

et

by ru

nnin

g th

e w

ater

unt

il it

beco

mes

as

cold

as

it wi

ll ge

t. Th

e w

ater

that

was

flu

shed

can

be

used

for n

on-

cons

umpt

ion

purp

oses

.Th

e En

viro

nmen

tal

Prot

ectio

n A

genc

y an

d th

e Te

xas

Dep

artm

ent o

f Hea

lth

agre

e th

at th

e m

ost e

ffect

ive

way

to p

rote

ct y

our f

amily

is

to fl

ush

the

tap

anyt

ime

wat

er h

as b

een

stan

ding

for

over

six

hou

rs.

• Nev

er c

ook

with

or

cons

ume

wat

er fr

om th

e ho

t-wat

er ta

p. H

ot w

ater

di

ssol

ves

lead

mor

e qu

ickl

y th

an c

old

wat

er. I

f you

nee

d ho

t wat

er, d

raw

wat

er fr

om

the

cold

tap

and

heat

it o

n th

e st

ove.

Nev

er u

se h

ot ta

p w

ater

for m

akin

g ba

by

form

ula.

Use

onl

y th

orou

ghly

flu

shed

wat

er fr

om th

e co

ld

tap

for a

ny c

onsu

mpt

ion.

• Be s

ure t

hat y

our

plum

ber o

nly

uses

lead

- fre

e so

lder

and

lead

-free

flux

when

m

akin

g re

pairs

or

inst

allin

g ne

w pl

umb

ing.

Lea

d-

free

sold

er

cont

ains

less

th

an 2

perc

ent l

ead

cont

ent.

Lead

-free

pi

pe c

onta

ins

less

than

Q

perc

ent l

ead

cont

ent.

• If y

ou li

ve in

a ne

w ho

me,

che

ck fa

ucet

sc

reen

s fo

r the

firs

t few

m

onth

s un

til a

ll sm

all

debr

is is

flus

hed

from

the

syst

em.

• If l

ead

is fo

und

to b

e a

prob

lem

in y

our h

ome,

the

mea

sure

s lis

ted

abov

e m

ay b

e al

l the

pro

tect

ion

you

need

. In

addi

tion,

poi

nt-

of-u

se tr

eatm

ent s

uch

as

reve

rse

osm

osis

dev

ices

are

co

mm

erci

ally

ava

ilabl

e.

Thes

e un

its m

ay b

e ei

ther

pu

rcha

sed

or le

ased

. H

owev

er, t

hey

can

be

expe

nsiv

e, th

eir e

ffect

ive

ness

var

ies,

and

they

mus

t be

mai

ntai

ned.

Sin

ce th

ese

devi

ces

also

sof

ten

wat

er,

they

sho

uld

only

be

inst

alle

d at

the

fauc

et.

If y

ou li

ve in

a

new

hom

e,

chec

k (h

e fa

ucet

sc

reen

s fo

r th

e fir

st f

ew

mon

ths

until

al

l sm

all

debr

is is

flu

shed

from

th

e sy

stem

.

I i

Fort

Wor

th W

ater

Dep

art m

ent T

akes

Ste

ps to

R

educ

e Le

ad E

xpos

ure

Oo

The

Wat

er

*•

Dep

artm

ent

uses

an

auto

mat

ic

anal

yzer

th

at

test

s d

rin

kin

g

wat

er f

or

sub

stan

ces

rang

ing

from

ch

lori

de

to

amm

on

ia.

The

Lab

ora

tory

te

sts

sam

ple

s fr

om m

ore

than

ZO

O s

ites

th

roug

hout

th

e ci

ty.

• The

dep

artm

ent i

s re

mov

ing

the

rem

aini

ng le

ad

pipe

s th

at w

ere

form

erly

in

stal

led

in th

e di

strib

utio

n sy

stem

.• T

he d

epar

tmen

t tre

ats

wat

er s

o it

is "h

arde

r" a

nd

actu

ally

hel

ps c

oat p

ipes

w

ith m

iner

al d

epos

its a

s it

pass

es th

roug

h th

em.

• The

dep

artm

ent i

s pa

rtici

patin

g in

a n

atio

nal

stud

y sp

onso

red

by th

e Am

eric

an W

ater

Wor

ks

Asso

ciat

ion

Res

earc

h Fo

unda

tion.

The

Env

iron

men

tal P

rote

ctio

n A

genc

y is

also

par

ticip

atin

g. T

he F

ort

Wor

th W

ater

Dep

artm

ent i

s on

e of

a h

andf

ul o

f wat

er

utilit

ies

sele

cted

to p

artic

i pa

te in

this

land

mar

k st

udy.

Th

e st

udy

to b

e co

nduc

ted

over

a o

ne-y

ear t

ime

span

wi

ll te

st fo

r the

pre

senc

e of

le

ad in

two

targ

eted

are

as:

sele

cted

new

hom

es a

nd

olde

r hom

es w

ith le

ad p

ipes

. W

ater

will

be te

sted

not

onl

y at

the

cons

umer

's h

ome,

but

al

so a

t dis

tribu

tion

site

s.• T

he d

epar

tmen

t in

stru

cts

day

care

sup

ervi

so

rs a

bout

saf

egua

rds

agai

nst l

ead

as p

art o

f the

ir an

nual

lice

nsin

g in

spec

tion.

• The

dep

artm

ent

help

ed th

e Fo

rt W

orth

* •a J I

Inde

pend

ent S

choo

l Dis

trict

en

sure

that

all

wat

er fo

un

tain

s ar

e fre

e fro

m le

ad.

• Thr

ough

this

bro

chur

e an

d ot

her m

eans

of c

omm

u ni

ty o

utre

ach,

the

depa

rt m

ent c

ontin

ues

to e

duca

te

the

publ

ic o

n sa

fegu

ards

ag

ains

t lea

d ex

posu

re.

Hom

e

Wat

er f

low

s fr

om t

he

rese

rvo

ir

thro

ugh

the

trea

tmen

t p

lan

t, o

n to

th

e w

ater

m

ain,

thr

ough

th

e se

rvic

e co

nn

ecto

r an

d

into

you

r ho

me.


Instructions for water samplingSoldered Copper Sites

PurposeThe purpose of this study is to examine the corrosive effects of "standing water" in household plumbing systems.

General guidelines• Since the purpose of this study is to monitor "standing water" under worst-case condi tions, please do not use water after going to bed on the night before the sampling. Do not flush the toilet or run water in the middle of the night. The water needs to stand in the pipes a minimum of six to eight hours before it is sampled.• The samples must be collected the first thing in the morning after the water has been in the plumbing all night. It is important that no other water is run before this sampling. That means you must collect the sample before flushing the toilet, running water for the morning coffee or taking a shower. This may be out of the ordinary for you, but it is essential to get valid information for the purposes of this study. Failing to do this may distort the study results and will prevent us from giving you accurate information about the quality of your water.• The third sample should be collected two minutes after the first two (leaving the water running continuously during the interim—if you wish you may save this water for other uses).

The sampling kitThe kit contains three bottles. Cold water should be collected in all of them.

#1 will hold 250 milliliters#2 will hold 750 milliliters#3 will hold 1 liter

SamplingAll samples are to be taken at the kitchen faucet first thing in the morning. The night before the sample, please remove the aerator from your faucet according to the instructions below. Here are the sampling steps:

The night before the sampling: If it is present, remove the faucet aerator (the small "screen" just inside the faucet) by un screwing it from the faucet. Most will come off easily, but if it is difficult to remove, use the appropriate tools.

The morning of the sampling:1. Place bottle # 1 under the faucet and

turn the cold water on.2. Immediately as bottle # 1 is filled,

turn the water off. Make sure not to waste any water before filling bottle # 2.

3. Place bottle # 2 under the faucet and turn the cold water on and fill it. Turn the water off. Make sure not to waste any water before filling bottle # 3.

4. Turn the water back on and let it run for two minutes. Then fill bottle # 3.

5. Cap all bottles tightly. Sampling is now finished, and you can resume your normal activities.

6. Place the samples in the bag pro vided and hang it from your front door handle. A laboratory technician will collect the sample.

QuestionsIf you have questions, please call 572-3154 during normal business hours.


Instructions for water samplingLead Service Sites

PurposeThe purpose of this study is to examine the corrosive effects of "standing water" in household plumbing systems.

General guidelines• Since the purpose of this study is to monitor "standing water" under worst-case condi tions, please do not use water after going to bed on the night before the sampling. Do not flush the toilet or run water in the middle of the night. The water needs to stand in the pipes a minimum of six to eight hours before it is sampled.• The first sample must be collected the first thing in the morning after the water has been in the plumbing all night. It is important that no other water is run before this sampling. That means you must collect the sample before flushing the toilet, running water for the morning coffee or taking a shower. This may be out of the ordinary for you, but it is essential to get valid information for the purposes of this study. Failing to do this may distort the study results and will prevent us from giving you accurate information about the quality of your water.• The second sample should be collected one minute after the first sample (leaving the water running continuously during the in terim—if you wish, you may save this water for other uses). The third sample should be collected two minutes after the second sample, again letting the water run continu ously.

The sampling kitThe kit contains three bottles. Cold water should be collected in all of them. Each bottle holds one liter of water.

SamplingAll samples are to be taken at the kitchen faucet first thing in the morning. The night before the sample, please remove the aerator from your faucet according to the instructions below. Here are the sampling steps:

The night before the sampling: If it is present, remove the faucet aerator (the small "screen" just inside the faucet) by un screwing it from the faucet. Most will come off easily, but if it is difficult to remove, use the appropriate tools.

The morning of the sampling:1. Place bottle # 1 under the faucet, and

turn the cold water on.2. After bottle # 1 is filled, turn the

water off. Make sure not to waste any water before filling bottle # 2.

3. Turn the water on and let it run for one minute. Then fill bottle # 2. Turn the water off. Make sure not to waste any water before filling bottle # 3.

4. Turn the water back on and let run for two minutes. Then fill bottle number # 3.

5. Cap all bottles tightly. Sampling is now finished, and you can resume your normal activities.

6. Place the samples in the bag pro vided and hang it from your front door handle. A laboratory technician will collect the sample.

QuestionsIf you have questions, please call 572-3154.

Appendix E__________

Example Bid Documents for Constructing the AWWARF Pipe Rack

377


PIPE RIGS AT ALTA MESA AND COMO PUMPSTATIONS PROJECT NUMBER PW53-060530171900

ADDENDUM NO 1

pate of Addendum: January 23, 1991i-'^-f - .

Date of Advertisement: January 11, 1991

BIDS TO BE RECEIVED: 1:30 pm, January 31, 1991

NOTICE TO BIDDERS

Clarification: Pipe loop fabrication must be performed by a licensed plumber. See E-2.

INFORMATION TO BIDDERS

The Special Contract Documents for the above Project are hereby revised and amended as follows:

SUPPLEMENTARY CONDITIONS: Add the following paragraphs to the Supplementary conditions:

!!19. WORKERS COMPENSATION (a) Contractor agrees to provide the Owner (City) a certificate showing that it has obtained a policy pf, workers insurance covering each of its employees employed on the project in compliance with state law. No Notice to Proceed will be issued until the Contractor has complied with this sect ion : T>

(b) Contractor agrees to require each and every subcontractor fchp;Will perform work on the project to provide to it a certificate showing that it has obtained a policy of workers insurance covering each of its employees employed on the project. Contractor will not permit any subcontractor to perform work on the project until such certificate has been acquired. Contractor shall provide a copy of all such certificates to the Owner (City)."

Add the form entitled "CONTRACTOR COMPLIANCE WITH WORKERS COMPENSATION LAW" after the Supplementary Conditions.

SECTION E-3

Page E-2, Paragraph C.3, revise to read as follows:

"3. The panel boards will be mounted in a storage andhydro-pneumatic control room at each pump stations. A grounded wall outlet is available within the room. The drains shall be routed to the janitor's sink with in the room. Water for the Rigs will be obtained by installing a tee in the supply line to the sink. The contractor shall remove the storage shelf system in Alta Mesa Pump station by cutting off the top section

Appendix E: Example Bid Documents 319

relocating it "'to the main pump station as directed the owner ;'^ Owner shall remove the storage shelf in Pumps tati on."- ; '.-;":"','/- "''.''•''. :

. .

E-S,; Section D, add the following, "All copper loops will be ^fabricated by the same licensed plumber in order to provide f Standardization of workmanship."•&*&:,- ,:.:.-;::-•.:;. •• ' . -:.- '•&$£''-'.-. ,- -,-'• ••:';•. - ' .|Figure E-l:: Clarification: The City will provide the timer IJWhich is a 120 volt, 1/3 hp, digital timer. It is designed to be plugged into a standard grounded, 110 volt, 1 phase, socket. The

^Contractor shall install a duplex outlet box on the board and a cord to the existing wall outlet.

'fable 4, Equipment and Material List for AWWA-RF Pipe Rig,

sw*?:>.",;;!!

1; Revise "135 ft 0.5 I.D. Lead Tube, .25 wall, (45 ft perloop)" to read "78 ft 0.75 I.D. Lead Tube, .25 wall,

X^: (26 ft per loop)".

•2. In column 5, "EES" means the Owner, in column 6, f : "Utility will provide" means the Contractor will! -:.;V.'•:''; provide.' •^••^'- . • '

?0.5" I.D., 0.25" wall lead tube" to read "0.75 € I.D., 0.25^ wall lead tube".

;vCiatification: In order to provide for the required 26glJpIfl":;-' ft of tubing, four loops of lead pipe will be required.

^Figure ;E-9, Material List, Revise for option D to allow ^connection of Item 1, 1/2" PVC threaded union, to Item 12, 0.75" alD lead tube. • • '>/ ;- ; : ..'•

Figure E-9, Material List, Revise (D) at bottom of Figure to read Lead tube, soft temper, 3/4"I.D., 1/4" wall."

>!*P^;V"- :' I:;- '

Bidders shall acknowledge the receipt of this addendum on the Bid Proposal.

- ^."_ | -"'.; -., '...v ••_•' .... .-....-

W.';-"-^:^":', ••'• ,.--'..David Ivory

rCity Manager City of Fortjlorth

la chews, P. E. Chief, Plant .Design Section


ATTACHMENT TO;' SUPPLEMENTARY CONDITIONS

CONTRACTOR COMPLIANCE WITH WORKERS COMPENSATION LAW

Pursuant to Article 8308-3.23 of Vernon's Annotated Civil statutes, Contractor certifies that it provides worker's compensation insurance coverage for all of it's employees employed on City of Fort Worth Project Number PW53-060530171900

CONTRACTOR

By:

Title

Date

STATE OF TEXAS

COUNTY OF TARRANT

BEFORE ME, the undersigned authority, on this day personally appeared _____________________, known to me to be the person whose name is subscribed to the foregoing instrument, and acknowledged to me that he executed the same as the act and deed of _______;______________ for the purposes and consideration therein expressed and in the capacity therein stated.

GIVEN UNDER MY HAND AND SEAL OF OFFICE this _________day of __________________, 19__.

Notary Public in and for the State of Texas


PIPE RIGS AT ALTA MESA AND COMOPUMPSTATIONS

PROJECT NUMBER PW53-060530171900

DAVID IVORY CITY MANAGER

LEE BRADLEY, JR DEPUTY DIRECTOR WATER DEPARTMENT

RECOMMENDED

APPROVED

APPROVED

APPROVED

RICHARD SAWEYDIRECTORWATER DEPARTMENT

S. Frank Crumb, Jr., P.E., Office Engineer

///^Deputy Director

Rtch fT~fL^, $iter Director6L 11GV Dallas Williams, P.E., Deputy Director Public Works


Pipe Rigs at Alta Mesa and Como Pumpstations Project Number PW53-060530171900

TABLE OF CONTENTS

A-l NOTICE TO BIDDERS

A-2 SPECIAL INSTRUCTIONS TO BIDDERS

B-l PART B - PROPOSAL

DISADVANTAGED BUSINESS ENTERPRISE BID SPECIFICATIONS

C-l PART C - GENERAL CONDITIONS

SC-1 SUPPLEMENTARY CONDITIONS

D-l PART D- SPECIAL CONDITIONS

E-l SECTION E -SPECIFICATIONS

TABLE 4 Equipmant and Material List for AWWA-RF Pipe RigFIGURE E-l AWWA-RF Pipe Loop ModelFIGURE E-2 AWWA-RF Inlet/Outlet sectionFIGURE E-3 AWWA-RF Pipe Loop Manifold SectionFIGURE E-4 AWWA-RF Pipe Loop End Manifold SectionFIGURE E-6 Lead Tube Test Loop for AWWA-RF Pipe Loop ModelFIGURE E-7 Soldered Copper Test Loop for AWWA-RF Pipe Loop

Model FIGURE E-9 Test Loop Connection Details for AWWA-RF Pipe Loop

Model


NOTICE TO BIDDERS

Sealed proposals for the furnishing of all materials and equipment and labor and all necessary appurtenances and incidental work to provide a complete and operable project designated as:


will be received at the Office of the Purchasing Manager, City of Fort Worth, located in the lower level of the Municipal Building, 1000 Throckmorton, Fort Worth, Texas until:

1:30 PM, Thursday January 31, 1991

and will then be publicly opened and read aloud in the City Council Chambers at approximately 2:00 PM that same day.

The Project includes the construction of a one-half inch copper test loop at the Alta Mesa Pump Station, 4328 Alta Mesa, and a three-quarter inch lead test loop at the Como Pumpstation, 5920 Blackmore Ave. Piping will include pumps and valves and be wall mounted on 3/4" plywood approximately 8" by 12' in size. The work is to be completed within 30 days of notice to proceed.

Prequalification of Bidders according to the Fort Worth Water Department Contract Specifications is not required. Contractors must be licenced plumbers.

A Prebid Conference will be held at 2:00 PM, on January 22, 1991, at the Rolling Hills Water Treatment Plant, 2500 Southeast Loop 820 (at Campus Drive).

Special Contract Documents, including site location map and detailed specifications, may be obtained at no cost at the Engineering Office of the Fort Worth Water Department, City Hall, 1000 Throckmorton Street, Fort Worth, Texas 76102

General Contract Documents and General Specifications for the Water Department projects, dated January 1, 1978, with amendments, also comprise a part of the Contract Documents for this project and may be obtained by paying $50.00 for each set, at the Engineering Office of the Fort Worth Water Department.

The City reserves the right to reject any or all bids and waive any of all irregularities. No bid may be withdrawn until the expiration of 45 days form the date bids are received.

David Ivory City Manager

Ruth Howard City Secretary

Publication: January 11, 1991 January 17, 1991


January 11. 1991

SUPPLEMENTARY CONDITIONSPIPE RIGS AT ALTA MESA AND COMO PUMPSTATIONS

PROJECT NUMBER PW53-060530171900

1. Instructions to Bidders: Contractors must possess any licenses required by law. (4/5/90)

2. Proposal Form: In Section C2-2.1 , delete last sentance of paragraph 1 and paragraphs 2 and 3. Insert the following:

"Bidder may be evaluated for responsibli1ity following receipt of bids. Bidder shall supply certified information concerning experience, equipment and financial stability within 3 working days of the request of the City."

"Affidavit concerning South African/Namibian Business Interests must be executed and filed with the Director of the Water Department not later than one week prior to receipt of bids." ( 1/16/90)"

3. Examination of Contract Documents and Site of Project: In Section C2-2.3, Paragraph 2, add the following to the last sentence: "except for changes in the site conditions caused by factors outside of the control of the Contractor which occur after the Contractor's inspection and prior to installation."

4. Interpretation and Preparation of Proposal: Part C - General Conditions, Section C2-2, exchange paragraphs C2-2.7, C2-2.8, and C2-2.9 with the following:

C2-2.7 DELIVERY OF PROPOSAL: No proposal will be considered unless it is delivered, accompanied by its proper Bid Security and other required material, to the Purchasing Manager or his representative at the official location and stated time set forth in the proposal at the proper time to the proper place. The mere fact that a proposal was dispatched will not be considered. The Bidders must have the proposal actually delivered. Each proposal shall be in a sealed envelope plainly marked with the word "PROPOSAL" and the name or description of the project designated in the "Notice To Bidders". The envelope shall be addressed to the Purchasing Manager, City of Fort Worth Purchasing Division, PO Box 17027, Fort Worth, Texas 76102."

C2-2.8 WITHDRAWING PROPOSALS: Proposals actually filed with the Purchasing Manager cannot be withdrawn prior to the time set for the opening of proposals. A request for non consideration or a proposal must be made in writing, addressed to the City Manager, and filed with him prior to the time set for the opening of proposals. After all proposals not requested for non-consideration are opened and publicly read aloud, the proposals for which non-consideration requests have been properly filed may, at the option of the Owner, be returned unopened.


January 11, 1991

C2-2.9 TELEGRAPHIC MODIFICATION OF PROPOSALS: Any bidder may modify his proposal by telegraphic communication at any time prior to the time set for opening proposals, provided such telegraphic communication is received by the Purchasing Manager prior to the said proposal opening time, and provided further, that the City Manager is satisfied that a written and duly authenticated confirmation of such telegraphic communication over the signature of the bidder was mailed prior to the proposal opening time. If such confirmation is not received within forty-eight (48) hours after the proposal opening time, no further consideration will be given to the proposal.

Bonds: Paragraph C3-3.7a Other Bonds: on the sixth line of the paragraph beginning "no sureties", delete the words "the City of Fort Worth". Para C3-3.11g, delete paragraph beginning "Local Agent for Insurance and Bonding"

5. Insurance for Subcontractors: In Section C3-3.ll, lines 4-5, After "and for all subcontractors", insert the following "The General Contractor may require all subcontractors to be insured and submit documentation ensuring that the requirements of C3-3.ll are met for all subcontractors."

6. Insurance limits. In Section C3-3.ll, after the word "occurrence", add "/aggregate".

7. Automobile Insurance Limits: Revise Paragraph C3-3.ll (d) so that the insurance limits are as follows:

Bodily Injury 250,000 each personBodily Injury 500,000 aggregateProperty Damage 100,000 aggregate

7.1 Umbrella Coverage: Section C3-3.ll, Para b., change "$2,000,000 umbrella policy" to read $1,000,000 umbrella policy"

8. Testing Costs: Section 5-5.12, revise the first'sentence to read as follows: "Where, as called for in the Contract Documents, tests of materials or equipment are necessary, such tests will be made at the expense of and paid for by the Contractor unless otherwise specifically provided for in the Technical Specificat ions."

9. Laws to be Observed: Section C6-6.1 , delete "or which may be enacted later. After the word "exist" add "at the time of the Contract or may be hereafter exist during the performance of the Contract."

10. Building Permits: Paragraph C6-6.2 Insert the following at the end of the paragraph, "Contractors are responsible for obtaining construction permits from the governing agencies. Contractor shall schedule all code inspections with the Code Inspection Department in accordance with the permit requirements


January 11, 1991

and submit copy of updated schedule to the Engineer weekly. City of Fort Worth plumbing, electrical and mechanical building permits are issued without charge. Water and sewer access fees will be paid by the Water Department. Any other permit fees are the responsibility of the Contractor." (4/25/90)

11. Partial Payments: Change Paragraph C8-8.4 to read as follows:

"PARTIAL PAYMENTS: On the first day of each month after the first month's work has been completed, the Director of the Water Department will make current estimates in writing of materials in place complete, the amount of work performed during the preceding month or period, and the value thereof at the unit prices contracted for as shown on the Proposal .

For contracts where the total contract price estimate at the time of execution of the contract is less than $25,000, the contractor shall submit only a final estimate at the completion of the all work. Where the duration of the contract exceeds 60 days, the contractor may submit monthly estimates.

For contracts where the total contract price estimate at the time of execution of the contract is less than $400,000.00, ninety (90) percent of the Director's estimate will be allowed the Contractor within 25 days after the regular estimate period, and the balance will be retained by the City until the final estimate is allowed and the work is accepted.

For contracts where the total contract price estimate at the time of execution of the contract is $400,000.00 or greater, ninety five (95) percent of the Director's estimate will be allowed the Contractor within 25 days after the regular estimate period, and the balance will be retained by the City until the final estimate is allowed and the work is accepted.

For Contracts including preselected equipment for which the Contractor is required to issue purchase orders or enter into a contract, and where the a separate schedule of payments is mandated, the Owner will pay to Contractor in accordance with that pay schedule with no additional withholding for the products and services covered by the preselection documents. (4/5/90)

The City reserves the right to withhold the payment of any monthly estimate if the Contractor fails to perform the work strictly in accordance with the specifications or provisions of the Contract ."

12. Right to Audit: Add the following to Section C8-8:

C-9-8.14 RIGHT TO AUDIT; "The Contractor agrees that the City shall, until the expiration of three years after final payment under this contract, have access to and the right to examine any directly pertinent books, documents, papers, and records of the


January 11, 1991

Contractor involving transactions relating to this Contract. Contractor agrees that the City shall have access during normal working hours and appropriate work in order to conduct audits in compliance with the provisions of this section, The City shall give Contractor reasonable advance notice of intended audits.

Contractor further agrees to include in all its subcontracts hereunder a provision to the effect that the subcontractor agrees that the City shall, until the expiration of three years after final payment under this contract, have access to and the right to examine any pertinent books, documents, papers, and records of such Subcontractor involving transactions relating to the subcontract. And further that City shall have access during normal working hours and appropriate work space in order to conduct audits in compliance with the provisions of this section. The City shall give subcontractor reasonable advance notice of intended audits."

13. SCHEDULE OF COSTS: Add the following to Section C8-8:

C8-8.15 SCHEDULE OF COSTS: Not required for this contract.

14. CONTINGENT AWARD OF CONTRACT: Not Applicable

15. C3-3.5 AWARD OF CONTRACT is modified to read as follows: The Owner reserves the right to withhold final action on the proposals for a reasonable time, not to exceed the period stated for the duration of the Bid Security stated in the Notice to Bidders or 90 days, whichever is shorter. (2/23/90)

16. REIMBURSEMENT OF GRANT FUNDS FOR SALVAGED EQUIPMENT: Not applicable.

17. Construction period shall be in calendar days as defined in Paragraph Cl-1.23.

18. C3-3.6 BONDS: Delete subparagraph b. MAINTENANCE BOND A Maintenance Bond is not required for this Project.

END OF SECTION


PART D - SPECIAL CONDITIONS

D-l GENERAL: Subject to modifications as herein contained, the Fort Worth Hater Department's General Contract Documents and General Specifications, effective July 1, 1978, are made part of the Contract Documents for this Project. The Plans, Special conditions and Provisions Documents, and the rules, regulations, requirements, instructions, drawings and details referred to my manufacturer's name, number or identification included therein as specifying, referring or implying product control, performance, quality, or other shall be binding upon the Contractor. The. Specifications and drawings shall be considered cooperative; therefor, work or material called for by one and not shown or mentioned in the other shall be accomplished or furnished in a faithful manner as though required by all.

The order or precedence in case of conflicts or discrepancies between various parts of the Contract Documents subject to the ruling of the Engineer shall generally, but not necessarily, follow the guidelines listed below:

1. Plans2. Contract Documents3. General Contract -Documents and General Specifications

The following Special Conditions shall be applicable to this project and shall govern any conflicts with the General Contract documents under the provisions stated above.

D-2 PROJECT DESIGNATION AND DESCRIPTION: Construction under these Special Documents shall be performed under the Fort Worth Water Department Designations:


D-3 PROJECT SIGNS: NOT REQUIRED

D-4 CITY FURNISHED MATERIALS: The City will furnish the material indicated on the Figures included at the end of the Specifications. The contractor may use 20 amp, 110 v power at wall sockets and potable water at existing wall hydrants. All other material and labor for construction of the project shall be furnished by the Contractor.

D-5 WAGE RATES The labor classifications and minimum wage rates set forth herein have been predetermined by the City ?Council of the City of Fort Worth, Texas, in accordance with statutory requirements, as being the prevailing classifications and rates that shall govern all work performed by the Contractor or any sub-contractor on the site of the project covered by these Contract Documents. In no event shall less than the following rates of wages be paid, (see attached)


SECTION E - SPECIFICATIONS JANUARY 1, 1978

All materials, construction methods and procedures used in this project shall conform to Sections El, E2, and E2A of the Fort Worth Water Department General Contract Documents and General Specifications which are hereby made a part of this contract document by reference for all purposes, the same as if copies verbatim herein, and such Sections are filed and kept in the office of the City Secretary of the City of Fort Worth as an official record of the City of Fort Worth.

INDEX

El MATERIAL SPECIFICATIONS

E2 CONSTRUCTION SPECIFICATIONS

E2A GENERAL DESIGN DETAILS


January 11, 1991

SECTION E-3

AWWA PIPELOOP

I GENERAL

A SCOPE

The Project includes the construction of a one-half inch copper test loop at the Alta Mesa Pump Station, 4328 Alta Mesa, and a three-quarter inch lead test loop at the Como Pumpstation, 5920 Blackmore Ave. Piping will include pumps and valves and be wall mounted on 3/4" plywood approximately 8' by 12' in size.

B. SUBMITTALS

Data sheets for all materials supplied by the Contractor.

C. OWNER SUPPLIED MATERIAL

1. The Owner will provide all items indicated as "by EES" on Figures E-l, E-2, E-3, E-7, and Table 4.

2. All solder will be supplied by the Owner.

3. Owner shall designate water supply point and drainage point within the pumpstation. Contractor shall be responsible for making connections and runds to water supply and running drain lines to existing floor drains. Water supply and drain lines shall be floor or wall mounted in order to avoid interfering with normal access to pumpstation equipment.

4. Owner shall supply 110 volt power at grounded wall outlet within 20 feet of the panel mounting location.

C. PRODUCT DELIVERY, HANDLING AND STORAGE

1. Contractor shall coordinate with the Owner for access to the Pump Stations and for areas within the Pumpstation to store the material.

2. Materials supplied by the Owner will be picked up by the Contractor at the NOrth Holly Water Treatment Plant, Fournier Ave, during normal work hours.

3. The Contractor may use the existing electrical outlets and water supply during fabrication of the rigs. Access to the pumpstation during fabrication of the rigs will be coordinated with the Owner at least one work day in advance.

D. FIELD QUALITY CONTROL

All loop fabrication work will be performed by a licensed plumber.


January 11, 1991

II MATERIALS

1. See Table 4.

2. Plywood shall be exterior grade, 3/4".

3. Plywood shall be sanded and edges smoothed and beveled.

4. Paint all wood with one coat of sealer both sides and two coats of Semi Gloss Enamel (Glidden Y-555-Line undercoater and Y4600-Line Spred Lustre Semi-Gloss, or equal) on the exposed' edges and front face. Paint color shall be chosen by Owner from manufacturers color selection sheet.

5. All mounting bolts, nuts, spacers and washers shall be stainless steel

III EXECUTION

1. Contractor shall provide all materials except those specified to be by Owner.

2. Board shall be finished by sanding and painting prior to mounting on the wall.

3. Boards shall be mounted with a clearance of 1/2" from the wall using 6 - 3/8" anchor bolts and spacers per board. Two additional finished 2x2x12" support legs shall support the bottom of the board on the floor.

4. Sufficient supports shall be provided to hold the piping, meters and valve assemblies rigidly in place.

5. Piping shall be fabricated in sections and mounted on the board.

IV ACCEPTANCE

1. Contractor shall report completion of work to Owner.

2. Preliminary inspection will be performed to develop punch list.

3. Following completion of punch list, contractor shall request Final Inspection and provide request for final payment with required waivers of lien and other closure documents.

V PAYMENT: See Supplementary conditions.

ooOoo


TABLE4

Equipment and Material List for AWWA-RF Pipe Rig

Quantity

46258511

106934428S

12851

15 ftIS ft3 ft

135 ft180 ft180 ft

1211

Misc.1

Misc.

Size On.)

1/2 fpt1/2 ft*3/4 socket3/4 fpt1/2 socket1/4 mpt3/4 fpt3/4 fpt3/4 socket1/2 fpt3/4 socket3/4 fpt1/2 fpt3/4 fpt3/4 socket1/2 socket1/2 fpt1/2 socket3/4.1/21/2x1/41/2 1 3/43/41/21OSLO.OS4SLO.0422 LD.13/4 x 3/4

1/3x33/4

Item Specification

Flow rate meter, 0-2 gpm, nonmetaUicCheck valve, diaphragm type, PVCUnion ban valve, PVCUnion ban valve, PVCUnion ban valve, PVCLabcock sample valve, PVCPressure regulating valve, PVC, 0-100 prig2-way solenoid valve, brass. 120 VACUnion, PVCUnion, PVCTee, PVCTee, PVCTee, PVC90 EH, PVC90 Ell, PVC90EU.PVC90 ED. PVC45 EU, PVCReducer bushing, slip, PVCReducer bushing, threaded, PVCReducer bushing, threaded, PVCPipe, schedule 80, PVCKpe, schedule 80, PVCReinforced PVC tubingLead tube, 02$ in. wan (45 feet per loop)Copper tube, (CO feet per loop)Lead soldered copper tube (£0 feet per loop)Adjustable tubing damps, SSTotalizing water meter, noonxtalUcProgrammable timer. 120 VAC, 6 cycle/dayMounting hardware, split ring hangers, etcPipe nipple, PVC threaded on one endPipe nipple, PBC, schedule 80, threaded

Legend

1110204

12623

1322145

237

2116191517

9, IS25-------1--

248

EESwill Utility will Provide Provide

XX

XXX

XXX

XXXXXXXXXXXXXXXXXX

X (Solder) X (Copper Tube)X

XX

XXX

• Material list does not include materials to construct CERL pipe loop, only connecting piping and fittings. Source: EES 1990

Sold

ered

Cop

per

or

Lead

Tub

e Te

st L

oops

3ot.o

e e.

Sole

noid

Val

veee

sI

FIG

TTRE

E-L

AWW

A-RF

Pip

e Loo

p M

odel

Sou

rce;

EES

199

0

I 60 a I


MX P1PC NIPPLES SHOW M£ THUMB

FIGURE EA AWWA-RF Inlet/Outlet SectionSource: EES 1990


uT®.

18

fTGUREE.3. AWWA-RFFipe Loop Manifold Section

Source: EES 1990


10-12"

FIGURE E.4. AWWA-RFF^eLoopEadMafflfoldSecdi

Source: EES 1990


Pipe Strap

Solder Fill

Reinforced PVC Tubing. T

™ c u-Hi 1

0.5- I.D.. 0.25' Wall Lead Tube

1-1/4." Hose Clamp, S.S.

FIGURE EA Lead Tube Test Loop for AWWA-RF Pipe Loop

Source: EES 1990


36'

44'

Pipe Strap

Shelf Support (top & bottom)

.7.5'-

0.5" 90 deg. Elbows (50/50 solder connections)

0.5' Type LCopper Tube

(9 loops)

38'

2't"

t-5'

Male Adapter (0.5' x 0.5')

FIGURE q.7, Soldered Copper Test Loop for AWWA-RF Pipe Loop

Source: EES 1990


MATERIAL LIST

Connector Specifications

Item

12

345 £

89

101112

Description

Union, 1/2*. PVC, schedule 80, (breaded endsSpecimen. 1/2*. schedule 40 Pipe, threaded ends and fittings (steel,galvanized steel, copper, red brass, etc)Copper flared connector, 1/T MPT to 1/2" tubeSpecimen, 1/2*. type L, copper tube, soft temper, flared endsCopper adaptor, 1/2* MPT to 1/2" tube, soldered endSpecimen, 1/2*. type L, copper tube, hard temper, soldered end and

Pipe nipple, schedule 80, PVC 1/2* x 3". one end threaded, one endsocketReducing coupling schedule 80, PVC, 1/2" x 3/4", socket endsPipe nipple, schedule 80, PVC, 3/4" x 3*. socket endReinforced PVC tubing, 1" x 4* lengthTubing damp, 1-1/4* adjustable, stainless steelSpecimen, 1/2* LD, 1/4" wall, lead tube

(A) Steel. Galvanized Steel, Copper, or Red Brass Pipe, 1/2*, Schedule 40,tflfOuftQ QCuQCS

(B) Copper tube, soft temper, 1/T, type L, flared tube fittings(C) Copper tube, hard temper, 1/7, type L, soldered fittings(D) Lead tube, soft temper, 1/7 LD.,1/4* wall

FIGURE E-9. Test Loop Connection Details for AWWA-RF Pipe Loop

Source: EES 1 990

Appendix F__________

ISWS Corrosion Coupon and Insert Test Results

Corrosion Coupon Test Results

Corrosion rate measurements were made for copper, lead-soldered, copper, and lead materials during the study. A total of sixteen corrosion specimens, both coupon and pipe insert types, were installed for various time intervals. In addition to measuring the corrosion rate by weight loss methods, the corrosion tests compared the results for the two types of specimens and identified procedural problems with the weight loss methods. The corrosion data are presented in Tables F.I, F.2, F.3, and F.4.

Specimens were installed for intervals varying from 114 to 264 days, as shown by Figure F.I. Multiple specimens were used to conform with the planned- interval test method described by Wachter and Treseder (1947). The corrosion data obtained by this method can be compared to evaluate the effect that a change in water quality may have on corrosion during a long-term study. For example, the corrosion rates for copper pipe inserts L174 and L192 should be identical because the inserts were exposed under the same conditions. The corrosion rate for insert L63 should also be comparable to those of inserts L174 andL192 as long as the water quality for the first 114days was equivalentto the water quality during the last 132 days of the study.

The corrosion rates for the copper specimens employed during the study are shown hi Figure F.2. A relatively constant corrosionrate was observed forthe copper inserts regardless of length of exposure. The copper coupons showed more variation (from 0.88 to 1.44 mdd) than the copper inserts (from 1.05 to 1.26 mdd). From previous studies by the ISWS using duplicate specimens, the method precision is estimated to be ±0.12 mdd for copper pipe inserts.

Pipe inserts have been preferred over coupons by the ISWS to measure corrosion rates because the data obtained from inserts have been more representative of pipe wall corrosion occurring in flowing water. The difference in the corrosion results for the two types of specimens did not appear to be significant in this study. The effect of flow on the corrosion of specimens is probably less significant hi a pipe loop study, where flow rate is carefully controlled and static flow is the predominant condition. A visible difference was noted in the appearance of surf ace films forming on the two types of copper specimens. Films on copperinserts were thin, striated, and blue-green in color, whereas films on copper coupons were brown to olive-green with fewer blue-green striations.

341


Table F.1 Corrosion rate measurements (50:50 lead-tin solder, %-inch pipe inserts), AWWARF model pipe rack, Illinois State Water Survey site

Specimen

P37P34P45

AreaOn.2)

10.3510.3510.35

Weight loss

000

(g).0492.0438.0566

Cleaningblank (g)

0.00300.00300.0030

Net loss(g)

0.04620.04080.0536

Installation period(in)

02 Jan02 Jan26 Apr

919191

(out)

26 Apr 9105 Sep 9115 Jan 92

Time(days)

114246264

Corrosion rate(mdd)

0.5960.2480.304

(mpy)

0.0930.0380.049

Table F.2 Corrosion rate measurements (%-inch copper pipe inserts) AWWARF model pipe rack, Illinois State Water Survey site

Specimen

L63 L188 L193 L174 L192

Area (in-2)

10.35 10.35 10.35 10.35 10.35

Weight loss(g)

0 0 0 0 0

.1006

.2221

.2038

.1231

.1071

Cleaning blank (g)

0.0147 0.0147 0.0147 0.0147 0.0147

Net loss(g)

0.0859 0.2074 0.1891 0.1084 0.0924


02 Jan 02 Jan 26 Apr 05 Sep 05 Sep

91 91 91 91 91

(out)

26 Apr 91 05 Sep 91 15 Jan 92 15 Jan 92 15 Jan 92

Time (days)

114 246 264 132 132

Corrosion rate(mdd)

1.128 1.262 1.072 1.229 1.048

(mpy)

0.181 0.203 0.172 0.197 0.168

Table F.3 Corrosion rate measurements (lead coupons), AWWARF model pipe rack, Illinois State Water Survey site

Specimen

PB325PB326PB315PB348

Area(in.2)

3.413.413.413.41

Weight loss(g)

0.03600.03810.01720.0880

Cleaningblank (g)

0.01590.01590.01590.0159

Net loss(g)

0.02010.02220.00130.0721


02 Jan 9126 Apr 9109 Sep 9102 Jan 91

(out)

26 Apr 9105 Sep 9115 Jan 9215 Jan 92

Time(days)

114132136378

Corrosion rate(mdd)

0.8050.7680.0440.870

(mpy)

0.1020.0970.0060.110

Table F.4 Corrosion rate measurements (copper coupons), AWWARF model pipe rack, Illinois State Water Survey site

Specimen

C064 C062 C350 C340

Area (in.2)

3.41 3.41 3.41 3.41

Weight loss(g)

0.0379 0.0620 0.0533 0.0279

Cleaning blank (g)

0.0019 0.0019 0.0019 0.0019

Net loss(g)

0.0360 0.0601 0.0511 0.0260


02 Jan 91 02 Jan 91 26 Apr 91 09 Sep 91

(out)

26 Apr 91 05 Sep 91 15 Jan 92 15 Jan 92

Time (days)

114 246 264 136

Corrosion rate(mdd)

1.442 1.121 0.880 0.877

(mpy)

0.231 0.182 0.142 0.150

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21.91.81.71.61.51.41.31.21.1

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0

Total weight lossNet loss, less cleaning blank

P32502 Jan 91 - 26 Apr 91

P32602 Jan 91 - 05 Sept 91

Time interval

P31502 Sept 91

15 Jan 92

P34802 Jan 91- 15 Jan 92

Figure F.3 Corrosion rates for lead coupons

£

10.9

0.8

0.7

0.6

0.5§8 0.4

U 0.3

0.2

0.1

0

Total weight lossNet loss, less cleaning blank

Insert P37 Insert P34 02 Jan 91-26 Apr 91 02 Jan 91 - 05 Sept 91

Insert P45 26 Apr 91 -15 Jan 92

Time interval

Figure F.4 Corrosion rates for lead-soldered (50:50 lead-tin) pipe inserts

Appendix F: ISWS Corrosion Coupon Test Results 345

The corrosion rates determined for lead coupons are shown in Figure F.3. Both the total weight loss and net weight loss values are shown to indicate the significant effect of the cleaning procedure on lead coupons. The cleaning blank reported forall specimens is the meanvaluedeterminedforreplicate specimens. Lead coupons were cleaned by a 2-minute immersion hi a 1 percent acetic acid solution maintained at a temperature of 60-70°C. This solution produced the blank that was the most consistent andhad the lowest weightless as compared to ammonium acetate and glacial acetic acid cleaning methods for lead specimens. The cleaning effect was less significant as the coupon exposure time was increased, as shown by the results for Coupon P348. The reason for me inconsistent results obtained for Coupon P315 was not identified. The low corrosion rate for lead in potable water and the variability in the weight loss method require that lead specimens be exposed for extended periods to obtain meaningful corrosion data. The use of replicate specimens would have provided more significant corrosion data and would perhaps have reduced the time required to obtain the data.

Three copper pipe inserts were dipped in a molten lead-tin solder (50:50) to produce the lead-soldered pipe inserts. The corrosion results for these specimens ranged from 0.25 to 0.60 mdd. Due to the lack of an accepted standard forprocessing lead-soldered specimens, the specimens were cleaned by the same procedure used to process the lead coupons. This procedure produced a small cleaning blank for the lead-soldered specimens, but the 1 percent acetic acid solution may not be entirely effective in the dissolution of metal oxides forming on the lead solder. Further studies using acetic acid and other solutions are required to identify the most acceptable method for cleaning lead-soldered specimens. The corrosion results for the lead- soldered pipe inserts are shown in Figure FA For this particular water supply, lead- tin-soldered specimens had a lower corrosion rate than lead specimens. The fact that the weight loss was similar for the three lead-tin-soldered inserts indicates that a protective film formed readily on the soldersurface that impeded corrosion on further exposure.

Summary and Recommendations for Coupon Test Methods________________________

Corrosion specimens are valuable tools for evaluating the corrosivity of water. Both coupon and pipe insert types of specimens can be utilized effectively hi corrosion studies for this purpose. Coupons cost less per specimen and are more readily available than pipe inserts. The environment within water distribution systems is better represented by pipe inserts when water flow is a factor to be considered in the study. Because flow conditions are carefully controlled by the A WW ARF pipe rack, the coupon type of specimen is recommended to permit the use of multiple specimens without unduly escalating the costs of conducting a study.

Multiple corrosion specimens should be employed to evaluate watertreatment strategies and corrosion effects onplumbing materials. Watercorrosivity, corrodibility of metal specimens, constraints on duration of study, variability hi treatment control, precision of measurements, and economic considerations are some of the factors that affect the quantity of corrosion specimens required for this purpose. The specific needs of a particular study will therefore vary, and specific guidelines must be


developed for each installation. When in-house expertise is not available, a corrosion specialist or consultant should be contacted to assist in designing and conducting the study.

Many references are available on using corrosion specimens in many environments, but a standard procedure has not been established for using coupons in potable water systems. Thus it is difficult to correlate corrosion data reported for different water supplies or at different locations in the same system. Simple specifications for corrosion specimens are not standardized; i.e., surface area, type, or material. The procedures used to determine the weight loss of specimens also need standardization. For some plumbing materials, additional research is necessary to develop cleaning procedures. This is especially true forthe various metal alloys such as solder and brass materials commonly found in plumbing systems.

Sufficient experience and knowledge are available to establish standards for utilizing copper, steel, lead, and zinc coupons or pipe inserts. The CERL-PLS has been adopted as part of the ASTM Standard Test Method D 2688-90, Corrosivity of Water in the Absence of Heat Transfer (Weight Loss Methods)(ASTM 1990). The ASTMmethod was employed forthe AWWARF study and satisfiedmost requirements. The test loop can be easily expanded to contain a larger number of specimens. Coupons and pipe inserts were easily installed and removed without disrupting the study. Although additional method development is needed, the ASTM method is recommended as the best technology currently available for evaluating the corrosivity of water.

Appendix G

Water Quality Data From the Pipe Rack and Distribution System Monitoring

347


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Appendix G: Water Quality Data 349

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DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

TEM

P 29 27 27 26 27 27 27 27 25 25 25 24 26 27 26 25 26 26 27 27 24 23 23 24

PH

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397

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320

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326

320

319

317

325

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T.A

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102

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4

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101

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103 96 102

101 90 97 102 96 99 97 103

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FREE 0.00

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0.00

0.00

0.00

0.00

0.05

0.00

0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

TOTA

L

2.0

2.4

1.9

3.0

1.9

2.7

2.7

2.8

1.9

3.3

2.0

1.7

2.8

2.2

1.5

1.9

2.0

2.6

2.9

2.7

1.9

2.0

2.3

2.0

CIT

Y O

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4

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4

0.01

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8.8

8.8

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6.7

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110 0 0 0

200 0 0 1 1 0 0 0 0 25 0 0 0

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112

0.49

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200

214

CIT

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DAY

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09/2

5/91

09/2

6/91

09/2

7/91

09/2

8/91

09/2

9/91

09/3

0/91

10/0

1/91

10/0

2/91

10/0

3/91

10/0

4/91

10/0

5/91

10/0

6/91

10/0

7/91

10/0

8/91

10/0

9/91

10/1

0/91

10/1

1/91

10/1

2/91

10/1

3/91

10/1

4/91

10/1

5/91

10/1

6/91

10/1

7/91

10/1

8/91

10/1

9/91

10/2

0/91

10/2

1/91

10/2

2/91

10/2

3/91

10/2

4/91

10/2

5/91

10/2

091

10/2

7/91

10/2

8/91

10/2

9/91

10/3

0/91

10/3

1/91

11/0

1/91

11/0

2/91

11/0

3/91

11/0

4/91

11/0

5/91

11/0

6/91

11/0

7/91

11/0

8/91

11/0

9/91

11/1

0/91

11/1

1/91

11/1

2/91

11/1

3/91

11/1

4/91

11/1

5/91

11/1

6/91

11/1

7/91

11/1

8/91

25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 a 9 10 11 12 13 14 IS 16 17 18

21 24 23 24 23 23 23 24 22 22 22 22 23 23 22 22 22 22 22 22 22 22 22 22 22 19 19 19 19 20 20 21 17 15 17 17 18 18 18

\ C

HLO

RIN

EpH

C

ON

D

T.A

LK

FREE

TO

TAL

7.9

8.0

8.1

8.0

8.1

8.0

7.9

7.9

8.1

8.1

6.1

7.9

8.0

8.0

8.0

8.0

8.0

7.9

7.9

8.0

8.0

8.0

8.0

8.0

8.1

8.0

8.1

7.9

7.9

7.9

8.1

8.1

7.7

8.0

8.1

8.0

8.1

6.0

8.2

335

333

335

333

368

330

327

332

372

327

329

327

323

330

329

332

332

331

324

335

335

335

339

402

341

335

351

350

335

333

338

342

322

339

382

335

342

340

393

107

109

106

106

108

105

109

106

102

100

101

113

108

106

105

105

105

107

111

103

104

108

106

110

105

109

105

105

111

109

122

108

105

108

110

102

106

106

109

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1.9

2.6

2.3

1.4

2.2

2.4

2.6

2.1 1.4

2.5

2.3

2.0

1.7

1.6

1.9

1.9

2.2

2.0

2.5

2.5

2.4

2.8

2.6

2.6

2.8

2.6

3.1

2.6

3.2

2.1

3.3

2.7

2.0

3.0

2.2

1.9

2.0

2.0

2.1

Pb

Cu

0.00

8 0.

01

0.00

6 <0

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0.00

3 <0

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0.00

3 <0

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0.00

3 <0

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0.00

5 <0

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0.00

4 0.

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0.00

5 0.

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7.9

7.5

7.9

7.9

8.2

8.0

8.4

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0.58

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CIT

Y O

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ATER

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TE

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01/1

3/92

01/1

4/92

01/1

5/92

01/1

6/92

01/1

7/92

01/1

8/92

01/1

9/92

01/2

0/92

01/2

1/92

01/2

2/92

01/2

3/92

01/2

4/92

01/2

5/92

01/2

6/92

01/2

7/92

01/2

8/92

01/2

9/92

01/3

0/92

01/3

1/92

02/0

1/92

02/0

2/92

02/0

3/92

02/0

4/92

02/0

5/92

02/0

6/92

02/0

7/92

02/0

8/92

02/0

9/92

02/1

0/92

02/1

1/92

02/1

2/92

02/1

3/92

02/1

4/92

02/1

5/92

02/1

6/92

02/1

7/92

02/1

8/92

02/1

992

02/2

0/92

02/2

1/92

02/2

2/92

02/2

3/92

02/2

4/92

02/2

5/92

02/2

6/92

02/2

7/92

02/2

8/92

02/2

9/92

03*1

/92

03/0

2/92

03/0

3/92

03/0

4/92

03/0

5/92

03/0

6/92

03/0

7/92

13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 1 2 3 4 5 6 7

11 9 10 10 10 9 9 10 9 9 10 10 9 10 9 9 9 10 11 10 10 10 11 12 12 12 13 12 14 12 11 12 13 13 12 12 12 13

WEE

KLY

CH

LOR

INE

pH

CO

ND

T.

ALK

FR

EE

TOTA

L Pb

C

u8.

18.

18.

68.

68.

7

8.6

8.5

8.7

8.4

8.5

8.1

8.5

8.2

8.4

8.3

8.5

8.2

8.4

8.4

8.1

8.1

8.4

8.4

8.5

8.1

8.4

8.5

8.2

8.2

8.5

8.4

8.2

8.4

8.4

8.4

8.0

8.0

354

354

321

327

314

342

332

321

336

336

326

332

339

354

353

356

365

379

372

372

364

364

360

354

347

347

352

354

359

355

351

354

367

383

397

412

413

402

100

102

102 97 97 104

100

103

102

100

100 99 98 106

108

113

110

117

115

116

117

116

109

110

106

110

106

107

111

110

112

112

114

118

123

128

128

125

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1.8

2.2

1.8

0.00

3 <0

.01

2.0

1.9

2.0

1.9

0.00

3 0.

052.

21.

7

2.1

2.2

0.00

3 <0

.01

1.9

2.1 1.9

1.9

1.9

0.00

2 <0

.01

2.0

2.3

2.0

2.2

2.0

0.00

8 0.

021.

81.

9

2.0

2.0

1.9

0.00

5 <0

.01

1.8

1.8

1.7

2.0

2.2

0.00

7 0.

031.

92.

1 1.7

1.9

2.0

0.00

4 <0

.01

2.0

2.0

D.O

. 8.5

9.9

9.9

8.8

9.2

9.4

9.3

8.4

HPC

T.C

OLI

.Ca

MO

NTH

LY

NH

4 O

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TPO

4 St

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N ZI

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CO

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TD

S

130

0.44

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<0.0

36.

140.

04

<0.0

2<1

218

130

0.39

<0

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<0.0

3 5.

05

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10.

02<1

236

156

0.50

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87

0.06

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8

DAIL

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LORI

NE

CIT

Y O

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ATER

DEP

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LABO

RATO

RY S

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DIV

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03/0

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03/0

9/92

03/1

0/92

03/1

1/92

03/1

2/92

03/1

3/92

03/1

4/92

03/1

5/92

03/1

6/92

03/1

7/92

03/1

8/92

03/1

9/92

03/2

0/92

03/2

1/92

03/2

2/92

03/2

3/92

03/2

4/92

03/2

5/92

03/2

6/92

03/2

7/92

03/2

8/92

03/2

9/92

03/3

0/92

03/3

1/92

04/0

1/92

04/0

2/92

04/0

3/92

04/0

4/92

04/0

5/92

04/0

6/92

04/0

7/92

04/0

8/92

04/0

9/92

04/1

0/92

04/1

1/92

04/1

2/92

04/1

3/92

04/1

4/92

04/1

5/92

04/1

6/92

04/1

7/92

04/1

8/92

04/1

9/92

04/2

0/92

04/2

1/92

04/2

2/92

04/2

3/92

04/2

4/92

04/2

5/92

04/2

6/92

04/2

7/92

04/2

8/92

04/2

9/92

04/3

0/92

05/0

1/92

DAY 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1

TEM

P 16 14 13 14 13 16 15 14 14 14 15 15 15 13 15 16 15 16 15 17 15 16 15 16 19 19 19 19 20 19 19 20 19

pH

CO

ND

T.

ALK

FR

EE

TOTA

L

7.9

7.9

7.9

7.9

8.0

8.0

7.9

8.1

8.4

8.1

8.1

8.2

8.0

7.7

7.7

8.2

8.3

8.2

8.0

8.2

8.2

8.0

7.9

8.2

8.0

8.2

8.1

8.1

7.9

8.0

8.1

7.9

8.1

360

357

367

352

358

353

363

334

364

364

358

347

350

359

360

356

356

357

361

348

354

351

359

356

348

356

358

330

312

305

308

321

327

110

114

113

111

109

111

113

112

107

118

113

115

112

114

111

109

109

112

112

108

106

110

112

111

113

112

116

104 91 84 86 97 96

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1.9

2.1

2.0

1.9

1.7

2.0

2.1 1.9

1.9

2.0

2.0

1.9

2.2

1.7

1.8

1.3

1.7

1.6

1.6

1.5

1.6

1.8

1.7

1.6

1.8

2.3

2.0

2.2 1.5

1.9

2.4

2.6

2.3

Pb 0.00

2

0.00

4

0.00

6

0.00

7

0.00

6

0.00

4

<0.0

02

WEE

KLY

Cu

D.O

.

<0.0

1

0.01

<0.0

1

9.9

HPC

T.

CO

LI.

SO

CaN

H4

MO

NTHL

Y

OPO

4 TP

O4

SKD2

IR

ON

ZINC

C

OLO

R

TDS

s I a R I10.3

100

8.5

40

<0.01

0.02

8.9

0

8.8

100

130

0.50

<0.03

<0.03

5.62

0.03

<0.02

237

0.02

<0.0

1

8.7

8.8

200 10

124

0.65

<0.0

3 5.

62<1

229

CIT

Y O

F FO

RT W

ORT

H W

ATER

DEP

ARTM

ENT

LABO

RATO

RY S

ERVI

CES

DIVI

SIO

N AW

WA-

RF P

IPE

LOO

P ST

UD

Y AL

TA M

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05/0

2/92

OS/

03/9

205

/04/

9205

/05/

9205

/06/

9205

/07/

9205

/08/

9205

/09/

9205

/10/

9205

/11/

9205

/12/

9205

/13/

9205

/14/

9205

/15/

9205

/16/

9205

/17/

9205

/18/

9205

/19/

9205

/20/

92O

S/21

/92

05/2

2/92

05/2

3/92

05/2

4/92

05/2

5/92

05/2

6/92

05/2

7/92

05/2

8/92

05/2

9/92

05/3

0/92

05/3

1/92

06/0

1/92

06/0

2/92

06/0

3/92

06/0

4/92

06/0

5/92

06/0

6/92

06/0

7/92

06/0

8/92

06/0

9/92

06/1

0/92

06/1

1/92

06/1

2/92

06/1

3/92

06/1

4/92

06/1

5/92

06/1

6/92

06/1

7/92

06/1

8/92

06/1

9/92

06/2

0/92

06/2

1/92

06/2

2/92

06/2

3/92

06/2

4/92

06/2

5/92

DAY

TE

MP

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

20 20 20 20 20 21 21 21 21 21 21 20 21 20 21 21 21 20 21 20 21 21 21 22 22 22 23 25 23 23 23 23 25 25 25 26 25

pH

CO

ND

T.

ALK

FR

EE

TOTA

L

8.0

6.1

8.1

8.2

8.1

8.1

8.2

8.3

8.3

8.2

8.3

8.2

8.2

8.2

8.3

8.0

8.1

8.2

8.1

8.2

8.5

8.1

8.2

8.1

8.3

8.2

8.3

7.9

8.1

8.0

8.2

8.1

8.1

8.1

8.0

8.1

8.1

320

306

320

315

314

316

310

312

307

311

329

323

326

323

320

333

332

344

339

323

307

257

312

447

316

278

319

310

334

325

340

311

311

321

441

326

330

97 93 97 94 95 91 88 87 88 87 104 94 98 95 95 102 98 103

103 95 82 66 87 114 90 76 90 89 94 92 94 89 83 88 116 87 124

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2.0

2.1

1.9

1.9

2.4

1.2

2.1

2.1

2.2

2.0

1.2

1.6

2.2

1.8

2.1

2.3

2.2

2.6

2.2

2.1

2.2

2.3

2.3

1.9

2.2

2.6

2.1 1.7

2.2

2.1

2.8

2.1

2.2

1.9

2.6

2.4

1.9

Pb

<0.0

02

<.00

2

<.00

2

•c.0

02

<0.0

02

<0.0

02

<0.0

02 <.00

2

Cu

WEE

KLY

D.O

. 7.9

7.9

HPC

T.C

OLI

.

60 10

CaN

H4

OPO

4

MO

NTHL

Y

TPO

4 S

O2

IRO

NZI

NC

CO

LOR

TD

S

<0.0

3

0.01

0.04

0.05

0.04

<0.0

2

0.03

7.9

5400

7.9

8.0

500

250

<0.01

<0.02

0.03

<0.02

0.02

<0.02

0.02

<0.02

7.3

450

6.9

5400

6.9

1600

123

0.62

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4.08

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<.02

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0.01

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349

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112

104

106

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3712

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aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Pb

COLD

10.

006

0.00

60.

012

0.00

70.

012

0.01

00.

002

0.00

60.

003

0.00

70.

004

0.00

40.

004

0.00

20.

002

0.00

20.

003

0.00

30.

006

0.00

30.

006

0.00

60.

002

0.00

40.

003

0.01

30.

007

0.00

60.

005

0.00

70.

006

0.00

20.

004

Pb

Pb

Cu

Cu

Cu

CO

LD2

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

S

0.00

70.

005

0.00

60.

005

0.01

30.

011

0.00

20.

004

0.00

20.

004

0.00

90.

002

0.00

20.

002

0.00

20.

002

0.00

30.

001

0.00

40.

002

0.00

40.

005

0.00

20.

003

0.00

20.

008

0.00

80.

007

0.00

70.

007

0.00

60.

002

0.00

4

0.00

40.

008

0.00

40.

003

0.01

40.

008

0.00

20.

002

0.00

20.

005

0.00

40.

002

0.00

20.

002

0.00

20.

002

0.00

20.

003

0.00

60.

002

0.00

20.

002

0.00

20.

002

0.00

20.

004

0.00

30.

008

0.00

50.

005

0.00

40.

002

0.00

2

0.63

0.62

0.30

0.27

0.80

0.74

0.59

0.74

0.68

0.42

0.44

0.29

0.32

0.34

0.45

0.51

0.96

0.80

0.66

0.32

1.00

0.86

0.63

0.80

0.76

0.69

0.67

0.58

0.33

0.20

0.22

0.54

0.44

0.72

0.56

0.53

0.32

0.86

0.75

0.68

0.75

0.72

0.40

0.63

0.20

0.24

0.32

0.52

0.56

1.17

0.12

0.89

0.46

1.21

0.91

0.82

0.77

0.78

0.78

0.68

0.54

0.34

0.22

0.22

0.47

0.48

0.30

0.07

0.06

0.04

0.10

0.09

0.33

0.22

0.18

0.57

0.63

0.27

0.18

0.32

0.30

0.22

0.19

0.05

0.84

0.48

0.22

0.20

0.34

0.20

0.23

0.24

0.08

0.09

0.05

0.05

0.04

0.22

0.09

85 b 1 1 •i, a •o •5' * § "? 3 §L

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

08/0

5/92

09/2

6/91

11/0

7/91

03/0

5/92

06/1

8/92

07/0

7/92

08/0

5/92

09/2

6/91

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/0

5/92

06/1

8/92

07/0

7/92

08/0

5/92

09/2

6/91

02/2

1/92

03/1

0/92

06/1

8/92

07/0

7/92

08/0

5/92

09/2

6/91

09/2

6/91

11/0

7/91

02/2

0/92

03/1

0/92

06/1

8/92

07/0

7/92

08/0

5/92

09/2

6/91

12/0

5/91

01/2

3/92

CU

ST

NO

C00

9C

010

C01

0C

010

C01

0C

010

C01

0C

011

C01

1C

011

C01

1C

011

C01

1C

011

C01

1C

011

C01

2C

012

C01

2C

012

C01

2C

012

C01

3C

014

C01

4C

014

C01

4C

014

C01

4C

014

C01

5C

015

C01

5

3704

3609

3609

3609

3609

3609

3609

4009

4009

4009

4009

4009

4009

4009

4009

4009

3608

3608

3608

3608

3608

3608

3700

7916

7916

7916

7916

7916

7916

7916

3708

3708

3708

AD

DR

ES

S

Fairh

aven

Dr.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Mar

sh L

ane

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Fairh

aven

Dr.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Pb

Pb

Pb

Cu

Cu

Cu

CO

LD1

CO

LD2

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

S

0.00

20.

008

0.00

80.

007

0.00

30.

003

0.00

20.

004

0.00

30.

006

0.00

40.

005

0.00

40.

002

0.00

30.

002

0.00

70.

005

0.00

40.

002

0.00

30.

002

0.00

70.

004

0.00

20.

008

0.00

80.

002

0.00

30.

002

0.01

20.

004

0.00

3

0.00

20.

003

0.00

40.

004

0.00

30.

003

0.00

30.

003

0.01

70.

006

0.00

30.

002

0.00

20.

002

0.00

20.

002

0.00

40.

002

0.00

20.

002

0.00

30.

002

0.07

30.

003

0.00

10.

007

0.00

60.

002

0.00

30.

003

0.00

40.

002

0.00

2

0.00

20.

005

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

004

0.00

40.

005

0.00

30.

002

0.00

20.

002

0.00

40.

002

0.00

20.

002

0.00

20.

002

0.00

30.

003

0.02

10.

002

0.00

30.

002

0.00

20.

002

0.00

30.

002

0.00

2

0.51

0.61

0.64

0.61

0.49

0.77

0.71

0.65

0.54

0.15

0.25

0.46

0.32

0.54

0.55

0.69

0.39

0.25

0.22

0.51

0.61

0.66

0.20

0.56

0.28

0.54

0.47

0.60

0.54

0.59

0.46

0.39

0.12

0.59

0.69

0.67

0.64

0.59

0.69

0.68

0.68

0.44

0.14

0.22

0.60

0.39

0.52

0.58

0.71

0.12

0.25

0.24

0.54

0.58

0.70

0.19

0.77

0.07

0.64

0.52

0.80

0.56

0.62

0.48

0.39

0.06

0.16

0.04

0.04

0.06

0.18

0.10

0.09

0.13

0.23

0.11

0.23

0.25

0.28

0.28

0.21

0.17

0.11

0.10

0.09

0.25

0.11

0.13

0.02

0.30

0.07

0.31

0.29

0.31

0.19

0.09

0.58

0.40

0.04

a*. !§ i. R' CJ 1 to !_ <5' I B <JU 8S

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

02/2

0/92

03/1

0/92

06/1

8/92

07/0

7/92

08/1

2/92

02/2

0/92

03/1

6/92

07/1

3/92

08/1

2/92

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/1

6/92

09/2

6/91

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/1

3/92

06/1

8/92

07/1

3/92

08/1

2/92

09/2

6/91

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/1

3/92

06/1

8/92

07/0

9/92

08/1

2/92

09/2

6/91

GU

ST

NO

C01

5C

015

C01

5C

015

C01

5C

016

C01

6C

016

C01

6C

017

C01

7C

017

C01

7C

017

C01

9C

019

C01

9C

019

C01

9C

019

C01

9C

019

C01

9C

020

C02

0C

020

C02

0C

020

C02

0C

020

C02

0C

020

C02

1

3708

3708

3708

3708

3708

3752

3752

3752

3752

6917

6917

6917

6917

6917

3605

3605

3605

3605

3605

3605

3605

3605

3605

3733

3733

3733

3733

3733

3733

3733

3733

3733

7937

AD

DR

ES

S

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Eagl

eroc

k Dr

.Ea

gler

ock

Dr.

Eagl

eroc

k Dr

.Ea

gler

ock

Dr.

Eagl

eroc

k Dr

.C

lear

Bro

ok C

ir.C

lear

Bro

ok C

ir.C

lear

Bro

ok C

ir.C

lear

Bro

ok C

ir.C

lear

Bro

ok C

ir.C

lear

Bro

ok C

ir.Cl

ear B

rook

Cir.

Cle

ar B

rook

Cir.

Cle

ar B

rook

Cir.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Fairh

aven

Dr.

Butte

rcup

Cir

N.

Pb

CO

LD1

0.01

10.

010

0.00

50.

003

0.00

20.

007

0.00

70.

003

0.00

20.

002

0.00

30.

003

0.00

80.

006

0.02

30.

010

0.00

50.

017

0.00

70.

006

0.00

20.

003

0.00

20.

006

0.00

60.

004

0.00

50.

008

0.00

70.

002

0.00

40.

002

0.00

9

Pb

CO

LD2

0.01

00.

009

0.00

60.

003

0.00

20.

005

0.00

40.

004

0.00

30.

002

0.00

30.

004

0.00

50.

004

0.00

90.

004

0.00

30.

005

0.00

70.

006

0.00

20.

004

0.00

30.

008

0.00

10.

003

0.00

20.

003

0.00

40.

002

0.00

30.

003

0.00

5

Pb

Cu

Cu

Cu

g C

OLD

S

CO

LD1

CO

LD2

CO

LDS

•§

"

0.01

30.

005

0.00

30.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

30.

002

0.00

70.

005

0.00

40.

002

0.00

30.

003

0.00

20.

003

0.00

20.

002

0.00

20.

004

0.00

20.

003

0.00

50.

003

0.00

20.

002

0.00

20.

002

0.00

6

0.22

0.18

0.36

0.20

0.25

0.52

0.48

0.78

0.66

0.21

0.27

0.12

0.30

0.31

0.70

0.50

0.62

0.23

0.60

0.58

0.63

0.62

0.58

0.13

0.84

0.72

0.37

0.54

0.39

0.45

0.56

0.64

0.11

0.10

0.14

0.35

0.23

0.27

0.44

0.43

0.81

0.69

0.16

0.31

0.31

0.27

0.26

0.98

0.49

0.60

0.22

0.61

0.61

0.70

0.67

0.62

0.57

0.83

0.12

0.35

0.62

0.37

0.82

0.59

0.68

0.62

0.10

0.11

0.09

0.05

0.04

0.04

0.05

0.12

0.11

0.04

0.26

0.02

0.09

0.10

1.04

0.03

0.03

0.05

0.03

0.05

0.23

0.11

0.09

0.47

0.43

0.12

0.06

0.32

0.07

0.38

0.12

0.11

0.70

a o tl •5- 1 5" S r» 2-

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/1

3/92

07/0

9/92

08/1

0/92

09/2

6/91

03/1

6/92

07/1

3/92

08/1

0/92

09/2

6/91

02/2

0/92

03/1

6/92

06/1

3/92

07/1

3/92

08/1

3/92

09/2

6/91

11/0

7/91

12/0

5/91

02/2

0/92

03/1

6/92

06/1

2/92

07/1

3/92

08/1

0/92

09/2

6/91

11/0

7/91

12/0

5/91

01/2

3/92

02/2

0/92

03/1

6/92

06/1

8/92

07/1

3/92

GU

ST

NO

C02

1C

021

C02

1C

021

C02

1C

021

C02

1C

022

C02

2C

022

C02

2C

023

C02

3C

023

C02

3C

023

C02

3C

024

C02

4C

024

C02

4C

024

C02

4C

024

C02

4C

025

C02

5C

025

C02

5C

025

C02

5C

025

C02

5

AD

DR

ES

S

7937

7937

7937

7937

7937

7937

7937

8029

8029

8029

8029

3620

3620

3620

3620

3620

3620

4344

4344

4344

4344

4344

4344

4344

4344

8045

8045

8045

8045

8045

8045

8045

8045

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Tree

Lea

fTr

ee L

eaf

Tree

Lea

fTr

ee L

eaf

Bret

tBr

ett

Bret

tBr

ett

Bret

tBr

ett

Phea

sant

Phea

sant

Phea

sant

Phea

sant

Phea

sant

Phea

sant

Phea

sant

Phea

sant

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

Butte

rcup

CirN

.C

irN.

CirN

.C

irN.

CirN

.C

irN.

CirN

.La

neLa

neLa

neLa

ne

Wal

kW

alk

Wal

kW

alk

Wal

kW

alk

Wal

kW

alk

Cir.

S.Ci

r. S.

Cir.

S.Ci

r. S.

Cir.

S.Ci

r. S.

Cir.

S.Ci

r. S.

Pb

Pb

Pb

Cu

Cu

Cu

CO

LD1

CO

LD2

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

3

0.00

40.

008

0.00

60.

006

0.00

60.

002

0.00

20.

004

0.00

40.

002

0.00

20.

005

0.00

60.

005

0.00

20.

004

0.00

20.

011

0.00

40.

003

0.00

50.

004

0.00

50.

003

0.00

20.

005

0.00

30.

004

0.00

40.

007

0.00

60.

002

0.00

2

0.00

30.

003

0.00

50.

002

0.00

20.

002

0.00

20.

003

0.00

20.

004

0.00

30.

011

0.00

70.

006

0.00

20.

003

0.00

30.

003

0.00

20.

003

0.00

30.

002

0.00

40.

004

0.00

40.

003

0.00

30.

004

0.00

30.

007

0.00

50.

002

0.00

2

0.01

00.

003

0.00

40.

006

0.00

30.

002

0.00

20.

001

0.00

20.

002

0.00

20.

020

0.00

20.

002

0.00

20.

002

0.00

20.

007

0.00

20.

004

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

003

0.00

20.

007

0.00

50.

002

0.00

2

0.52

0.48

0.24

0.50

0.41

0.21

0.19

0.70

0.62

0.48

0.51

0.04

0.48

0.36

0.21

0.35

0.29

0.21

0.30

0.29

0.29

0.25

0.27

0.66

0.59

0.11

0.63

0.30

0.27

0.68

0.45

0.54

0.44

0.63

0.57

0.25

0.50

0.43

0.23

0.22

0.78

0.64

0.53

0.55

0.37

0.49

0.37

0.36

0.36

0.34

0.78

0.22

0.14

0.21

0.20

0.23

0.68

0.65

0.99

0.65

0.35

0.31

0.79

0.49

0.68

0.46

0.08

0.18

0.03

0.17

0.11

0.05

0.04

0.69

0.42

0.20

0.17

0.33

0.06

0.07

0.15

0.07

0.09

0.82

0.17

0.09

0.11

0.09

0.10

0.13

0.10

0.11

0.60

0.42

0.06

0.10

0.11

0.27

0.08

f 18 & Cl ^ 1 3 <o <5 & ti

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d C

oppe

r Site

s

SA

MP

LE

GU

ST

DA

TE

NO

08/1

0/92

02/2

0/92

03/1

6/92

07/1

3/92

08/1

0/92

01/2

3/92

02/2

0/92

03/1

9/92

07/2

0/92

08/1

0/92

01/2

3/92

02/2

0/92

03/1

9/92

07/2

0/92

08/1

0/92

01/2

3/92

02/2

0/92

03/1

9/92

06/1

8/92

07/2

0/92

08/1

0/92

01/2

3/92

03/1

9/92

07/2

0/92

08/1

0/92

01/2

3/92

02/2

0/92

03/1

9/92

01/2

3/92

02/2

0/92

03/1

9/92

07/2

0/92

08/1

0/92

C02

5C

026

C02

6C

026

C02

6C

027

C02

7C

027

C02

7C

027

C02

8C

028

C02

8C

028

C02

8C

029

C02

9C

029

C02

9C

029

C02

9C

030

C03

0C

030

C03

0C

031

C03

1C

031

C03

2C

032

C03

2C

032

C03

2

8045

7909

7909

7909

7909

7620

7620

7620

7620

7620

7761

7761

7761 36

1736

1778

1378

1378

1378

1378

1378

1351

2951

2979

1679

1680

1780

1780

1751

3351

3351

3351

3351

33

AD

DR

ES

S

Butte

rcup

Cir.

S.

Clea

r Bro

ok C

ir.Cl

ear B

rook

Cir.

Clea

r Bro

ok C

ir.Cl

ear B

rook

Cir.

Gra

ssla

nd D

r.G

lass

land

Dr.

Gla

ssla

nd D

r.G

lass

land

Dr.

Gla

ssla

nd D

r.G

rass

land

Dr.

Gla

ssla

nd D

r.G

lass

land

Dr.

Bret

tBr

ett

Oce

an C

t.O

cean

Ct.

Oce

an C

t.O

cean

Ct.

Oce

an C

t.O

cean

Ct.

Dewd

rop

Ln.

Dewd

rop

Ln.

Valve

rde

Ln.

Valve

rde

Ln.

Mor

ning

Ln.

Mor

ning

Ln.

Mor

ning

Ln.

Dewd

rop

Ln.

Dewd

rop

Ln.

Dewd

rop

Ln.

Dewd

rop

Ln.

Dewd

rop

Ln.

Pb

COLD

10.

002

0.01

40.

011

0.00

50.

002

0.00

20.

003

0.00

80.

004

0.00

30.

003

0.00

90.

003

0.00

30.

002

0.00

50.

015

0.01

10.

008

0.00

30.

002

0.00

30.

003

0.00

30.

003

0.00

50.

008

0.00

60.

003

0.00

60.

003

0.00

30.

000

Pb

CO

LD2

0.00

20.

008

0.00

80.

006

0.00

40.

003

0.00

20.

004

0.00

40.

003

0.00

40.

005

0.00

20.

002

0.00

20.

002

0.01

50.

010

0.00

50.

002

0.00

30.

007

0.00

30.

002

0.00

20.

005

0.00

80.

006

0.00

30.

004

0.00

50.

004

0.00

3

Pb

Cu

Cu

Cu

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

S

0.00

20.

005

0.00

40.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

90.

007

0.00

40.

002

0.00

20.

003

0.00

20.

002

0.00

20.

004

0.00

40.

004

0.00

30.

004

0.00

30.

002

0.00

2

0.49

0.30

0.28

0.75

0.71

0.21

0.36

0.35

0.65

0.61

0.07

0.69

0.22

0.63

0.59

0.27

0.75

0.42

0.67

0.63

0.57

0.28

0.24

0.54

0.66

0.27

0.85

0.44

0.08

0.78

0.29

0.74

0.70

0.56

0.35

0.31

0.77

0.73

0.26

0.25

0.39

0.66

0.70

0.01

0.72

0.25

0.68

0.63

0.12

0.71

0.38

0.83

0.63

0.61

0.27

0.26

0.58

0.68

0.28

1.02

0.52

0.34

0.95

0.25

0.79

0.73

0.10

0.03

0.04

0.15

0.13

0.01

0.04

0.11

0.10

0.08

0.01

0.12

0.07

0.10

0.08

0.05

0.22

0.18

0.80

0.15

0.11

0.07

0.08

0.11

0.09

0.13

0.57

0.14

0.32

0.20

0.08

0.23

0.16

s I a c 1 § •§ 3 s s.

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

01/2

3/92

03/1

9/92

07/2

0/92

08/1

0/92

01/2

3/92

02/2

0/92

03/1

9/92

01/2

3/92

02/2

0/92

03/1

9/92

06/1

8/92

07/2

0/92

08/1

0/92

01/2

0/92

02/2

0/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

02/2

0/92

03/2

4/92

02/2

0/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

02/2

0/92

03/2

4/92

07/2

0/92

08/1

2/92

02/2

0/92

03/2

4/92

06/1

8/92

GU

ST

NO

C03

3C

033

C03

3C

033

C03

4C

034

C03

4C

035

C03

5C

035

C03

5C

035

C03

5C

036

C03

6C

036

C03

6C

036

C03

6C

037

C03

7C

038

C03

8C

038

C03

8C

038

C03

9C

039

C03

9C

039

C04

0C

040

C04

0

8024

8024

8024

8024

8725

8725

8725

5065

5065

5065

5065

5065

5065

2544

2544

2544

2544

2544

2544

5066

5066

2605

2605

2605

2605

2605

5051

5051

3916

3916

7749

7749

7749

AD

DR

ES

S

Mor

ning

Ln

Mor

ning

Ln

Mor

ning

Ln

Mor

ning

Ln

Mor

ning

Ln.

Mor

ning

Ln.

Mor

ning

Ln.

Gol

den

Ln.

Gol

den

Ln.

Gol

den

Ln.

Gol

den

Ln.

Gol

den

Ln.

Gol

den

Ln.

Cou

ntry

Cre

ekC

ount

ry C

reek

Cou

ntry

Cre

ekC

ount

ry C

reek

Cou

ntry

Cre

ekC

ount

ry C

reek

Gol

den

Ln.

Gol

den

Ln.

Cou

ntry

Cre

ekC

ount

ry C

reek

Cou

ntry

Cre

ekC

ount

ry C

reek

Cou

ntry

Cre

ekG

olde

n Ln

.G

olde

n Ln

.C

hest

nut

Che

stnu

tG

rass

land

Dr.

Gra

ssla

nd D

r.G

rass

land

Dr.

Pb

Pb

Pb

Cu

Cu

Cu

COLD

1 C

OLD

2 CO

LDS

COLD

1 C

OLD

2 C

OLD

3

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

Ln.

0.00

60.

006

0.00

20.

002

0.00

90.

006

0.00

40.

005

0.01

00.

009

0.00

20.

004

0.00

30.

003

0.01

20.

009

0.00

40.

003

0.00

20.

009

0.00

80.

002

0.00

20.

002

0.00

30.

002

0.00

40.

004

0.00

20.

002

0.00

20.

002

0.00

2

0.00

50.

006

0.00

20.

002

0.01

20.

009

0.00

20.

003

0.00

90.

004

0.00

20.

005

0.00

40.

002

0.00

90.

005

0.00

20.

002

0.00

20.

007

0.00

60.

002

0.00

20.

002

0.00

20.

002

0.00

60.

004

0.00

30.

002

0.00

50.

004

0.00

2

0.00

30.

002

0.00

20.

002

0.00

30.

013

0.00

20.

006

0.00

80.

004

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

009

0.00

40.

002

0.00

20.

002

0.00

20.

002

0.00

50.

002

0.00

20.

002

0.00

30.

002

0.00

2

0.26

0.38

0.50

0.48

0.25

0.82

0.27

0.34

0.85

0.43

0.68

0.52

0.49

0.56

0.88

0.66

0.65

0.56

0.50

0.78

0.46

0.01

0.34

0.67

0.36

0.34

0.70

0.64

0.61

0.62

0.80

0.66

0.65

0.14

0.42

0.53

0.52

0.27

0.49

0.30

0.35

0.87

0.45

0.56

0.55

0.54

0.55

0.93

0.69

0.78

0.55

0.57

0.68

0.44

0.62

0.28

0.81

0.37

0.38

0.79

0.68

0.65

0.69

0.74

0.70

0.63

0.02

0.19

0.13

0.11

0.02

0.41

0.09

0.20

0.42

0.26

0.70

0.09

0.11

0.06

0.12

0.12

0.38

0.14

0.09

0.10

0.09

0.08

0.08

0.34

0.09

0.07

0.12

0.14

0.10

0.09

0.04

0.08

0.30

> "8 p. Ci 1 t 1 »Tf § s fee ftn

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

07/2

0/92

08/1

2/92

07/2

2/92

08/1

2/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

03/2

4/92

07/2

0/92

08/1

2/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

03/2

4/92

07/2

0/92

08/1

2/92

03/2

4/92

06/1

8/92

03/2

4/92

06/1

8/92

07/2

0/92

08/1

2/92

06/1

8/92

07/2

2/92

08/1

2/92

06/1

8/92

06/1

8/92

CU

ST

NO

C04

0C

040

C04

1C

041

CC

001

CC

001

CC

001

CC

001

CC

002

CC

002

CC

002

CC

002

CC

003

CC

003

CC

003

CC

004

CC

004

CC

004

CC

004

CC

005

CC

005

CC

005

CC

006

CC

006

CC

007

CC

007

CC

007

CC

007

CC

009

CC

009

CC

009

CC

009

CC

010

7749

7749

5249

5249

7513

7513

7513

7513

7429

7429

7429

7429

7421

7421

7421

7513

7513

7513

7513

7509

4717

4717

7512

7512

7405

7405

7405

7405

5517

5517

5517

5521

7532

AD

DR

ES

S

Gra

ssla

nd D

r.G

rass

land

Dr.

Hunt

ersr

idge

Rd.

Hunt

ersr

idge

Rd.

Olym

pic

Trai

lO

lympi

c Tr

ail

Olym

pic

Trai

lO

lympi

c Tr

ail

Los

Padr

es T

rail

Los

Padr

es T

rail

Los

Padr

es T

rail

Los

Padr

es T

rail

Arca

dia

Trai

lAr

cadi

a Tr

ail

Arca

dia

Trai

lLo

s Pa

dres

Tra

ilLo

s Pa

dres

Tra

ilLo

s Pa

dres

Tra

ilLo

s Pa

dres

Tra

ilLo

s Pa

dres

Tra

ilBr

acke

nres

Tra

ilBr

acke

nres

Tra

ilLo

s Pa

dres

Tra

ilLo

s Pa

dres

Tra

ilCa

tlow

Ct.

Catlo

w Ct

.Ca

tlow

Ct.

Catlo

w Ct

.Bi

g Be

n Rd

.Bi

g Be

n Rd

.Bi

g Be

n Rd

.Bi

g Be

n Rd

.Po

int R

eyes

Pb

COLD

10.

002

0.00

20.

002

0.00

20.

004

0.00

30.

002

0.00

20.

002

0.00

20.

002

0.00

20.

006

0.00

20.

002

0.00

40.

002

0.00

20.

002

0.00

40.

002

0.00

20.

003

0.00

30.

003

0.00

30.

002

0.00

30.

002

0.00

20.

002

0.00

20.

002

Pb

CO

LD2

0.00

20.

002

0.00

30.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

40.

002

0.00

20.

005

0.00

20.

002

0.00

30.

004

0.00

30.

003

0.00

40.

002

0.00

30.

003

0.00

30.

002

0.00

20.

002

0.00

20.

003

0.00

2

Pb

Cu

Cu

Cu

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

S

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

003

0.00

20.

002

0.00

20.

002

0.00

20.

005

0.00

2

0.74

0.70

0.45

0.41

0.32

0.73

0.52

0.59

0.46

0.93

0.41

0.45

0.51

0.37

0.42

0.41

0.68

0.45

0.49

0.38

0.55

0.58

0.57

0.49

0.43

0.40

0.44

0.45

0.26

0.36

0.41

0.63

0.47

0.77

0.72

0.47

0.44

0.34

0.64

0.55

0.63

0.46

0.93

0.46

0.50

0.54

0.39

0.47

0.46

0.83

0.49

0.53

0.40

0.52

0.63

0.59

0.59

0.41

0.44

0.46

0.49

0.29

0.37

0.48

0.55

0.66

0.15

0.11

0.12

0.07

0.09

0.36

0.09

0.12

0.10

0.32

0.16

0.18

0.03

0.02

0.11

0.04

0.31

0.01

0.14

0.06

0.03

0.14

0.08

0.38

0.06

0.07

0.08

0.09

0.06

0.05

0.10

0.65

0.33

1 a "a H' § 1? 3 ^

Fort

Wor

th W

ater

Dep

artm

ent

Lead

Sol

dere

d Co

pper

Site

s

SA

MP

LE

DA

TE

07/2

2/92

06/1

8/92

07/2

2/92

08/1

8/92

06/1

8/92

07/2

2/92

06/1

8/92

07/2

2/92

08/1

9/92

06/1

8/92

07/2

2/92

08/1

9/92

07/2

2/92

08/1

8/92

07/2

2/92

08/1

8/92

07/2

8/92

08/1

8/92

06/1

8/92

06/1

8/92

06/1

8/92

06/1

8/92

CU

ST

NO

CC

010

CC

011

CC

011

CC

011

CC

012

CC

012

CC

013

CC

013

CC

013

CC

014

CC

014

CC

014

CC

015

CC

015

CC

016

CC

016

CC

017

CC

017

CC

018

CC

019

CC

020

CC

021

7532 34

1359

3359

3373

3273

3232

4532

4532

4574

6274

6274

6247

2547

2531

2431

2473

3673

3639

1676

0555

1338

21

AD

DR

ES

S

Poin

t Rey

esFo

rest

Cre

ek D

r.Hu

nber

tHu

nber

tIn

dian

aIn

dian

aKa

thy

LnKa

thy

LnKa

thy

LnPo

int R

eyes

Poin

t Rey

esPo

int R

eyes

Wat

erw

ayW

ater

way

Ston

ewal

lSt

onew

all

Indi

ana

Indi

ana

Ches

tnut

Cres

cent

Crat

er L

ake

Dr.

Hunt

wick

Dr.

Pb

Pb

Pb

Cu

Cu

Cu

CO

LD1

CO

LD2

CO

LDS

C

OLD

1 C

OLD

2 C

OLD

S

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

60.

002

0.00

40.

002

0.00

20.

003

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

003

0.00

20.

002

0.00

30.

002

0.00

20.

002

0.00

20.

003

0.00

30.

003

0.00

30.

002

0.00

30.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

40.

002

0.00

40.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.00

20.

002

0.55

0.58

0.39

0.44

0.88

0.44

0.76

0.25

0.29

0.51

0.29

0.31

0.44

0.48

0.26

0.30

0.45

0.49

0.52

0.51

1.05

0.78

0.59

0.67

0.42

0.45

0.99

0.49

0.74

0.29

0.32

0.52

0.35

0.31

0.46

0.51

0.29

0.35

0.49

0.54

0.41

0.64

1.01

1.01

0.14

0.68

0.09

0.08

0.32

0.11

0.57

0.04

0.06

0.53

0.08

0.09

0.07

0.12

0.04

0.07

;§

0.09

g

0.11

|

0.19

0

0.51

^

0.34

|

0.39

-

DA

TE

DAY

TEM

P pH

DAIL

YC

HLO

RIN

E C

ON

D

T.A

LK

FREE

TO

TAL

08/0

1/91

08

/02/

91

08/0

3/91

08

/04/

91

08/0

5/91

08

/06/

91

08/0

7/91

08

/08/

91

08/0

9/91

. 08

/10/

91

08/1

1/9

1 0*

12/9

1 08

/13/

91

08/1

4/9

1 08

/15/

91

08/1

6/91

08

/17/

91

08/1

8/91

08/1

9/91

08/2

0/91

08/2

1/91

08/2

2/91

08/2

3/91

08/2

4/91

08/2

5/91

08/2

6/91

08X2

7/91

08/2

8/91

0079

/91

08/3

0/91

08/3

1/91

09/0

1/91

09/0

2/91

09/0

191

09/0

4/91

09/0

5/91

09/0

6/91

09/0

7/91

09/0

8/91

09/0

9/91

09/1

0/91

09/1

1/91

09/1

2/9

109

/13/

9109

/14/

9109

/15/

9109

/16/

9109

/17/

9109

/18/

9109

/199

109

/20/

9109

/21/

9109

/22/

9109

/23/

9109

/24/

91

1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

30 28 28 27 27 27 27 27 25 24 23 24 27 26 25 27 27 27 25 23 23 23

7.9

7.8

7.6

8.1

8.1

8.1

8.2

8.0

8.1

7.9

7.6

8.0

7.8

7.9

7.9

7.9

7.8

7.7

7.9

8.0

7.9

8.0

395

392

393

430

414

414

410

400

407

403

381

381

405

405

403

399

406

412

403

411

410

416

93 94 98 117

105

105

101

108

106

107

106

102

101

105 98 96 102

102 94 99 104

104

0.00

0.00

0.00

0.00

0.00

0.00

0.05

0.00

0.00 0 0 0 0 0 0 0 0 0 0 0 0 0

3.0

3.7

2.9

2.1

3.0

3.6

3.5

3.5

2.9

2.7

3.1

3.5

2.0

2.4

1.7

1.8

1.5

2.2

1.3

1.9

3.1

3.5

CIT

Y O

F FO

RT W

ORT

H W

ATER

DEP

ARTM

ENT

LABO

RATO

RY S

ERVI

CES

DIV

ISIO

N AW

WA-

RF P

IPE

LOO

P ST

UD

Y C

OM

O P

UMP

STAT

ION

- IN

FLU

ENT

Pb

WEE

KLY

Cu

D.O

. HP

C T.

CO

LI.

8.5

8.5

7.8

7.3

5.7

80 120 0 6 0 50 35 17 540 50 100 10 100 3 2 15 0 13 100 0

CaN

H4

MO

NTHL

Y

OP

04

TP04

SK

>2

IRO

N ZI

NC

CO

LOR

TDS

0.03

0.

03

112

0.58

<0

.01

0.22

<1

264

262

277

8W>

8

seat

eb oo

o

KiniAinN. r^K^tAco in in in p p v- 01 CNI p o> O»K<OIOK 01 h* * i^ K N nncieoco oicincncn eocicimn crt cj m* co cvi W oi « «' oi «•> oi ci oi N o*

3|o'

ooooo ooooo ooooo ooooo ooooo ooooo ooooo o

S88S8 88888 gfefeS? 8St6§ ^?888 SSSSS 28688 8

^- «D r- o» *

CD (D CO CO CDp 01 <- 0> p 00 OD CO KOO oo K oj to a

cncnppp ~ p p ^ c>KKflOCOflO CO'COCDCOK r-: r~ cd <o co

CrTY

OF

FORT

WO

RTH

WA

TER

DEP

AR

TMEN

T LA

BORA

TORY

SER

VIC

ES D

IVIS

ION

AWW

A-RF

PIP

E LO

OP

STU

DY

CO

MO

PUM

P ST

ATIO

N - I

NFLU

ENT

DAT

E11

/1 9/

9111

/20/

9111

/21/

9111

/22/

9111

/23/

9111

/24/

9111

/25/

9111

/26/

9111

/27/

9111

/28/

9111

/29/

9111

/30/

9112

/01/

9112

/02/

9112

/03/

9112

/04/

9112

/05/

9112

/06/

9112

/07/

9112

/08/

9112

/09/

9112

/10/

9112

/11/

9112

/12/

9112

/13/

9112

/14/

9112

/15/

9112

/16/

9112

/17/

9112

/18/

9112

/19/

9112

/20/

9112

/21/

9112

/22/

9112

/23/

9112

/24/

9112

/25/

9112

/26/

9112

/27/

9112

/28/

9112

/29/

9112

/30/

9112

/31/

9101

/01/

9201

/02/

9201

/03/

9201

/04/

9201

/05/

9201

/06/

9201

/07/

9201

/08/

9201

/09/

9201

/10/

9201

/11/

9201

/12/

92

DAY 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12

TEM

P 15 14 13 13 13 12 12 10 11 11 11 12 13 13 15 14 13 14 13 12 12 12 12 12 10 10 10 10 11 10 10 11 12 10 11

DAI

LYC

HLO

RIN

EpH

C

ON

D

T.A

LK

FREE

TO

TAL

8.4

B.2

8.3

8.3

8.4

8.3

8.0

7.9

7.9

8.1

8.1

7.8

8.0

8.1

8.1

8.0

7.9

7.9

7.8

8.1

7.9

8.0

8.3

8.3

8.3

8.3

8.3

8.3

8.2

8.3

8.2

8.3

8.3

8.2

8.2

410

408

404

406

404

405

405

413

415

408

411

411

410

410

412

404

409

404

412

412

411

407

362

361

255

372

362

369

350

341

339

338

382

342

326

107

109

111

110

107

113

111

111

108

113

112

115

108

111

110

115

109

111

113

114

115

115

100 95 104

100 97 97 94 94 87 86 87 90 97

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2.7

2.4

2.3

2.2

2.3

2.4

2.4

1.9

2.5

2.7

3.2

3.2

2.1

1.7

1.9

1.9

1.1

0.7

3.3

3.3

2.9

3.2

2.8

2.8

2.8

2.7

3.1

2.8

2.7

2.7

3.2

2.3

2.8

2.7

2.7

Pb 0.00

4

<.00

1

0.00

2

0.00

2

0.00

3

<0.0

02 0.00

2

WEE

KLY

MO

NTHL

Y

CuD.

O.

HPC

T.C

OLI

.Ca

N

H4

OP

04

TPO

4 S

O2

IRO

N ZI

NC

CO

LOR

TD

S

0.01

<0.01

<002

<0.0

1

<0.0

1

8.5

9.0

a o

110

118

0.46

<0

.01

<0.0

14.

2 0.

030.

12<1

242

9.3

250

8.9

100

9.0

7511

6 0.

91

<0.0

1 <0

.01

2.26

0.

23

<0.0

2<1

243

0.02

9.1

8

<0.0

18.

6 15

0

CIT

Y O

F FO

RT W

ORT

H W

ATER

DEP

ARTM

ENT

LABO

RATO

RY S

ERVI

CES

DIVI

SIO

N AW

WA-

RF P

IPE

LOO

P ST

UDY

CO

MO

PUM

P ST

ATIO

N - I

NFLU

ENT

DAI

LY

DAT

E01

/13/

9201

/14/

9201

/15/

9201

/16/

9201

/17/

9201

/18/

9201

/19/

9201

/20/

9201

/21/

9201

/22/

9201

/23/

9201

/24/

9201

/25/

9201

/26/

9201

/27/

9201

/28/

9201

/29/

9201

/30/

9201

/31/

9202

/01/

9202

/02/

9202

/03/

9202

/04/

9202

/05/

9202

/06/

9202

/07/

9202

/08/

9202

/09/

9202

/10/

9202

/11/

9202

/12/

9202

/13/

9202

/14/

9202

/15/

9202

/16/

9202

/17/

9202

/18/

9202

/19/

9202

20/9

202

21/9

202

/22/

9202

/23/

9202

/24/

9202

/25/

9202

/26/

9202

27/9

202

/28/

9202

/29/

9203

/01/

9203

/02/

9203

/03/

9203

/04/

9203

/05/

9203

/06/

92

DAY

TE

MP

13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 1 2 3 4 5 6

12 9 9 9 9 8 8 11 9 9 9 9 9 10 9 9 9 10 10 10 10 10 10 11 12 11 13 12 13 13 11 11 12 12 13 13 14 14

WEE

KLY

CH

LOR

INE

pH

CO

ND

T.

ALK

FR

EE

TOTA

L Pb

C

u7.

97.

78.

08.

08.

2

7.9

7.8

7.9

7.9

8.0

8.0

8.0

7.7

8.0

8.1

8.1

7.8

8.0

7.9

8.0

7.9

8.0

8.0

8.1

7.7

7.7

8.2

8.3

8.0

7.9

7.9

8.0

8.1

8.0

8.1

8.0

7.8

7.8

361

360

364

368

363

374

374

379

379

379

376

378

376

379

382

383

384

383

380

395

391

392

396

390

398

397

400

397

399

393

404

403

416

416

424

425

421

104

101

108

105

109

112

113

108

111

111

110

111

111

113

111

113

112

114

112

120

121

121

120

117

118

120

116

119

120

124

127

123

126

123

129

127

125

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2.8

3.1

3.0

0.00

4 <0

.01

2.9

3.3

2.6

2.9

0.00

6 <0

.01

2.7

2.9

2.8

2.8

0.01

8 <0

.01

2.8

2.8

2.6

2.6

2.3

<0.0

02

<0.0

12.

72.

3

2.7

2.7

2.8

0.00

3 0.

012.

82.

8

3.2

3.1

2.8

0.00

6 <0

.01

3.0

2.9

2.8

2.8

2.7

0.00

3 <0

.01

2.8

2.8

2.8

2.9

2.9

0.00

3 0.

022.

72.

8

D.O

. 8.5

10.0

10.0 8.7

9.4

9.4

9.3

8.4

HPC

T.C

OLI

.

300

150

150

100

100

Ca

MO

NTHL

Y

NH

4 O

PO4

TPO

4 SK

>2

IRO

N ZI

NC

COLO

R TD

S

120

0.61

<0

.03

<0.0

3 6.

40

0.40

<0

.02

<124

5

122

0.58

<0

.03

<0.0

3 6.

78

<0.0

1 <0

.02

<126

9

1013

4 0.

59

<0.0

3 <0

.03

4.2

0.03

<0

.02

<128

5

03/0

7/92

DAIL

YCH

LORI

NED

ATE

03/0

8/92

03/0

9/92

03/1

0/92

03/1

1/92

03/1

2/92

03/1

3192

03/1

4/92

03/1

5/92

03/1

6/92

03/1

7/92

03/1

8/9

203

/19/

9203

/20/

9203

/21/

9203

/22/

9203

/23/

9203

/24/

9203

/25/

9203

/26/

9203

/27/

9203

/28/

9203

/29/

9203

/30/

9203

/31/

9204

/01/

9204

/02/

9204

/03/

9204

/04/

9204

/05/

9204

/06/

9204

/07/

9204

/08/

9204

/09/

9204

/10/

9204

/11/

9204

/1 2

/92

04/1

3/92

04/1

4/92

04/1

5/92

04/1

6/92

04/1

7/92

04/1

8/92

04/1

9/92

04/2

0/92

04/2

1/92

04/2

2/92

04/2

3/92

04/2

4/92

04/2

5/92

04/2

6/92

04/2

7/92

04/2

8/92

04/2

9/92

04/3

0/92

05/0

1/92

DAY

TE

MP

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 1

17 15

•14 14 14 15 15 15 15 15 15 15 14 13 15 16 16 16 15 15 17 16 17 16 17 20 19 20 20 21 20 20 19 20

pH

CO

ND

T.

ALK

FR

EE T

OTA

L

7.6

7.7

7.7

7.4

7.6

7.7

7.7

7.8

8.1

7.8

7.9

7.9

7.9

7.6

7.9

6.4

8.4

8.3

8.3

6.2

8.1

8.1

7.8

8.0

8.1 8.0

8.2

7.9

8.0

7.7

7.9

7.9

8.1

7.9

425

422

434

487

451

448

454

421

458

458

461

457

456

461

465

463

461

463

466

469

465

471

466

469

467

476

478

475

476

478

479

480

475

474

129

129

130

129

133

138

138

136

138

134

139

138

139

139

139

136

138

138

137

142

137

140

142

139

139

128

126

145

141

135

141

141

140

124

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2.3

2.4

2.5

2.3

2.3

2.6

2.6

2.8

2.7

2.7

2.8

2.7

2.3

2.7

2.3

2.4

2.4

2.4

2.4

2.3

2.3

2.4

2.3

2.4

2.3

2.3

2.0

2.9

2.8

1.9

2.8

2.8

2.0

2.4

CIT

Y O

F FO

RT

WO

RTH

WAT

ER D

EPAR

TMEN

T LA

BORA

TORY

SER

VIC

ES D

IVIS

ION

AWW

A-RF

PIP

E LO

OP

STU

DY

CO

MO

PUM

P ST

ATIO

N - I

NFLU

ENT

Pb

WEE

KLY

Cu

D.O

.

0.00

3 <0

.02

0.00

6 <0

.02

0.00

2 <0

.02

9.9

HPC

T.C

OLI

.

40

MO

NTH

LY

NH

4 O

PO4

TPO

4 S

O2

IRO

N ZI

NC

C

OLO

R

TDS

10.2

15

0

8.4

100

1 •a, •§ I 8

0.00

60.

01

0.00

7 <0

.01

8.8

100

8.8

100

<0.0

1 <0

.02

0 134

0.58

<0.03

<0.03

5.22

0.01

<0.02

314

0.004

0.01

<0.002

0.07

8.7

8.6

100 20

<0.01

<0.02

138

0.61

<0.03

<0.03

4.27

<0.01

<0.02

<132

9

DAIL

YC

HLO

RIN

E

CIT

Y O

F FO

RT W

ORT

H W

ATER

DEP

AR

TMEN

T LA

BORA

TORY

SER

VICE

S DI

VISI

ON

AWW

A-RF

PIP

E LO

OP

STU

DY

CO

MO

PUM

P ST

ATIO

N - I

NFLU

ENT

DAT

E 05

/02/

9205

/03/

9205

/04/

9205

/05/

9205

/06/

9205

/07/

9205

/08/

9205

/09/

9205

/10/

9205

/11/

9205

/12/

9205

/1 3

/92

05/1

4/92

05/1

5/92

05/1

6/92

OS/

17/9

205

/18/

9205

/19/

9205

/20/

9205

/21/

9205

/22/

9205

/23/

9205

/24/

9205

/25/

9205

/26/

9205

/27/

9205

/28/

9205

/29/

9205

/30/

9205

/31/

9206

/01/

9206

/02/

9206

/03/

9206

/04/

9206

/05/

9206

/06/

9206

/07/

9206

/08/

9206

/09/

9206

/10/

9206

/11/

9206

/12/

9206

/13/

9206

/14/

9206

/15/

9206

/16/

9206

/17/

9206

/18/

9206

/19/

9206

/20/

9206

/21/

9206

/22/

9206

/23/

9206

/24/

9206

/25/

92

DAY

TE

MP

2 3 4 5 6 7 6 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

23 21 22 21 21 23 22 22 23 23 23 22 22 22 21 22 22 22 21 20 21 21 21 22 23 23 23 24 23 26 26 26 25 27 26 27 27 25

pH

CO

ND

T.

ALK

FR

EE

TOTA

L

7.7

7.9

7.9

8.0

8.1

7.7

7.9

7.9

8.0

7.9

7.9

7.8

7.8

7.9

7.9

7.9

7.7

7.7

7.8

7.9

8.0

8.0

8.1

8.0

8.0

8.0

7.9

8.0

8.1

7.8

7.9

8.0

7.9

8.1

8.1

8.0

8.0

8.0

469

462

476

466

465

463

460

468

467

467

479

478

476

471

471

470

469

471

478

487

484

490

480

488

483

497

512

503

504

504

499

503

486

489

489

463

478

480

134

134

134

136

137

128

124

125

133

132

138

137

134

133

134

133

128

130

132

139

133

180

132

133

124

128

132

131

130

124

125

126

124

123

123

118

116

105

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

2.6

2.6

2.4

2.1

2.1 1.6

2.2

1.8

1.9

1.8

2.0

2.4

2.2

2.6

1.9

1.9

2.1 1.9

2.3

2.6

2.6

2.8

2.4

2.6

1.8

2.1

2.6

2.8

1.9

2.9

3.5

4.1

3.7

3.4

3.2

2.8

2.6

2.4

Pb

<0.0

02

<.00

2

<.00

2

<.00

2

0.00

8

<0.0

02

<0.0

02 <.00

2

Cu

WEE

KLY

D.O

.

0.06

7.6

7.6

7.2 7.9

HPC

T.C

OLI

.

410

200

500

200

Ca

NH4

OPO

4

MO

NTH

LY

TPO

4 S

O2

IRO

NZI

NC

COLO

R TD

S

0.07

7.5

1000

7.5

7.1

130

150

125

0.62

<0.0

34.

18•e

.01<.

02<1

325

0.17

6.8

800

0.02

<.

02

Fort

Wor

th W

ater

Dep

artm

ent

Stan

ding

Sam

ples

Co

mo

Pipe

Rac

k

Ul 8

Day _ D

ate

1 09

/04/

917

09/1

1/91

15

09/1

9/91

21

09/2

5/91

28

10/0

2/91

35

10/0

9/91

42

10/1

6/91

49

10/2

3/91

56

10/3

0/91

63

11/0

6/91

70

11/1

3/91

77

11/2

0/91

84

11/2

7/91

91

12/0

4/91

98

12/1

1/91

105

12/1

8/91

113

12/2

6/91

118

12/3

1/91

126

01/0

8/92

134

01/1

6/92

140

01/2

2/92

147

01/2

9/92

154

02/0

5/92

161

02/1

2/92

168

02/1

9/92

175

02/2

6/92

182

03/0

4/92

189

03/1

1/92

196

03/1

8/92

203

03/2

5/92

210

04/0

1/92

217

04/0

8/92

224

04/1

5/92

231

04/2

2/92

238

04/2

9/92

245

05/0

6/92

252

05/1

3/92

259

05/2

0/92

266

05/2

7/92

273

06/0

3/92

280

06/1

0/92

287

06/1

7/92

294

06/2

4/92

i0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

Tem

p

30 30 26 24 26 26 24 24 18 19 20 20 20 26 24 22 17 19 20 15 23 24 18 19 27 21 19 26 28 24 24 24 24 24 24 24 24 26 26 26 26

PH 8.0

8.0

8.1

8.0

7.8

7.9

7.6

8.0

7.7

8.0

7.9

7.9

7.9

8.1

7.9

8.2

8.5

8.1

8.2

8.2

8.0

8.0

8.1

8.1

7.9

8.0

8.4

7.8

8.2

8.3

8.0

8.2

8.1

8.0

8.0

8.1

7.8

8.0

8.0

8.0

8.1

Cond

T.

Alk.

457

422

396

436

411

435

433

433

422

439

419

429

424

417

407

410

381

370

343

361

382

385

390

388

395

401

417

374

366

466

474

473

481

470

445

394

472

486

497

485

490

100

102 95 99 107

109

109

113

110

110

108

109

109

113

107

115

103 97 89 98 105

100

114

118

121

121

137

117

115

136

139

141

143

135

112 94 107

134

130

124

125

Free

C

L To

tal C

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1.7

2.5

2.0

3.0

2.5

3.5

3.7

3.0

2.8

3.5

1.8

2.4

2.4

2.0

1.4

2.5

2.8

2.8

2.5

2.0

2.9

1.9

1.8

1.8

2.7

2.5

2.7

2.6

2.2

2.0

2.3

2.1

2.0

1.6

1.6

1.6

1.6

2.0

0.1

1.5

1.3

Pb 0.70

50.

020

0.02

00.

429

0.02

20.

373

0.03

30.

583

0.05

50.

100

0.17

30.

158

0.08

00.

249

0.31

00.

026

0.07

30.

106

0.14

60.

224

0.25

70.

316

0.09

80.

237

0.23

20.

249

0.29

20.

323

0.31

20.

248

0.23

00.

371

0.30

1

1.05

70.

898

0.22

70.

189

0.20

10.

432

Cu

<0.0

10.

02<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<.01

<.01

<.01

<.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

10.

010.

010.

01<0

.01

0.02

<.01

<.01

<.01

<.01

0.01

<.01

<.01

0.08

D.O

.

9.6

7.5

8.1

8.3

8.3

8.8

7.7

7.1

7.9

8.3

8.4

8.1

7.6

7.9

8.1

8.6

8.1

8.5

8.2

8.1

7.8

8.5

9.3

8.1

8.0

9.4

9.3

9.3

8.1

7.8

8.1

8.1

8.0

8.7

8.2

8.6

7.3

7.0

6.8

7.7

7.6

HP

C

T. C

oli

540

540

540

540

540

250

540

100 85 1

100

100

480

540

540

540

540

540

5400

1000

5400

5400 50

054

0054

0054

0054

0054

0054

0054

0054

0054

00

5400

5400

5400

5400

5400

5400

5400

5400

5400

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ca

120

104 90 104

102

106

108

110

110

112

113

110

112

108

110

110

110

110

112

110

122

120

122

128

126

126

154

140

144

144

144

142

141

138

129

114

136

160

158

158

148

NH

4

0.50

0.41

0.55

0.56

0.73

7.50

0.45

0.66

0.71

0.59

0.70

0.46

0.68

0.45

0.75

0.66

0.88

0.76

0.57

0.53

,0.

460.

560.

540.

550.

680.

770.

950.

420.

860.

640.

51

0.52

0.67

0.50

0.41

0.43

0.65

0.53

0.51

0.60

OP

O4

0.46

0.02

0.27

0.09

<0.0

1<0

.01

0.18

0.04

0.43

0.60

<0.0

1<0

.01

<0.0

1<0

.01

<0.0

1<0

.03

<0.0

3<0

.03

<0.0

3<0

.03

<0.0

3<0

.03

0.11

<0.0

3<0

.03

<0.0

30.

14<0

.03

<0.0

3

<0.0

3<0

.03

<0.0

3<0

.03

<0.0

3<0

.03

<0.0

3

<0.0

3

TP

04

0.03

0.03

0.01

0.08

0.59

<0.0

10.

23

<0.0

1

<0.0

1<0

.01

<0.0

10.

05<0

.01

<0.0

3<0

.03

<0.0

3<0

.03

<0.0

3

<0.0

3<0

.03

0.04

0.50

<0.0

3<0

.03

<0.0

3<0

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<0.0

3<0

.03

<0.0

3<0

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<0.0

3

SiO

2 Iro

n Zi

nc

Col

or

TDS

0.02

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7.56

0.

06

<0.0

2 <

7.02

0.

05

<0.0

2 <

6.94

0.

02

<0.0

2 <

6.66

<0

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<0.0

26.

94

<0.0

1 <0

.02

6.65

<0

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<0.0

26.

36

<0.0

1 <0

.02

5.52

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<0.0

25.

35

0.04

<0

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29

0.03

0.

12

<

5.07

0.

02

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25.

06

0.02

0.

033.

48

0.01

1.

914.

34

<0.0

1 0.

025.

88

0.10

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6.09

0.

88

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5.70

0.

12

<0.0

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6.56

0.

05

0.14

<

6.30

0.

04

0.22

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0.

01

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3.43

0.

26

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26.

59

0.01

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2.93

0.

17

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64

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3.19

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25.

27

0.01

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4.38

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24.

12

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4.91

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<.02

5.16

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01

<.02

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01

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6.15

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04

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284

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1:1

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3:1

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3:1

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3:1

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2:1

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2:1

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61

293

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279

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276

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275

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256

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248

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238

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91

259

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264

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246

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317

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319

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318

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321

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309

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Fort Worth Water Department Lead Service Sites


PERIOD DATE NO12345678912345678912346789112345678946712323456

10/03/91 L00111/21/91 L00112/12/91 L00101/30/92 L00102/27/92 L00103/1 0/92 L00106/23/92 L00107/07/92 L00108/1 9/92 L00110/03/91 L00211/21/91 L00212/12/91 L00201/30/92 L00202/27/92 L00203/10/92 L00206/23/92 L00207/09/92 L00208/1 8/92 L00210/03/91 LOOS11/21/91 LOOS12/12/91 LOOS01/30/92 LOOS03/1 0/92 LOOS06/23/92 LOOS07/09/92 LOOS08/1 8/92 LOOS10/03/91 L00410/03/91 LOOS11/21/91 LOOS12/12/91 LOOS01/30/92 LOOS02/27/92 LOOS03/1 0/92 LOOS06/23/92 LOOS07/09/92 LOOS08/21/92 LOOS01/30/92 L00603/1 0/92 L00606/23/92 L00610/03/91 L00711/21/91 L00712/12/91 L00711/21/91 LOOS12/12/91 LOOS01/30/92 LOOS02/27/92 LOOS03/1 1/92 LOOS

house PB1 PB2 PB311111111122222222233333333455555555566677788888

0.0020.0080.0080.0020.0050.0050.0040.0040.0060.0050.0090.0140.0020.0070.0070.0020.0060.0050.0920.0030.0160.0190.0150.0170.0180.0150.0030.0020.0020.0100.0020.0050.0050.0060.0090.0080.0020.0020.0030.0090.0040.0140.0050.0200.0030.0110.010

0.0030.0040.0030.0020.0070.0070.0050.0050.0070.0050.0060.0160.0020.0060.0040.0020.0080.0060.0050.0080.0150.0020.0140.0060.0200.0180.0030.0090.0010.0140.0020.0060.0060.0050.0110.0120.0030.0030.0020.0080.0050.0090.0060.0140.0020.0070.008

0.0030.0110.0020.0030.0040.0030.0040.0020.0020.0030.0120.0090.0020.0030.0020.0020.0020.0020.0040.0070.0140.0020.0100.0040.0080.0050.0020.0090.0010.0060.0020.0070.0060.0030.0020.0020.0020.0020.0020.0090.0040.0170.0030.0130.0020.0070.006


Fort Worth Water DepartmentLead Service Sites

PERIOD DATE NO house PB1 PB2 PB37 06/23/92 LOOS 8 0.002 0.005 0.0098 07/09/92 LOOS 8 0.015 0.019 0.0079 08/21/92 L008 8 0.019 0.019 0.0041 10/03/91 L009 9 0.004 0.015 0.0102 11/21/91 L009 9 0.001 0.001 0.0013 12/12/91 L009 9 0.007 0.009 0.0104 01/30/92 L009 9 0.003 0.002 0.0035 02/27/92 L009 9 0.005 0.006 0.0056 03/11/92 L009 9 0.005 0.004 0.0047 06/23/92 L009 9 0.002 0.003 0.0021 10/17/91 L010 10 0.013 0.013 0.0091 10/03/91 L011 11 0.006 0.004 0.0031 10/10/91 L012 12 0.009 0.009 0.0112 11/21/91 L012 12 0.001 0.003 0.0023 12/12/91 L012 12 0.008 0.003 0.0061 10/10/91 L013 13 0.010 0.007 0.0041 10/10/91 L014 14 0.012 0.007 0.0131 10/03/91 L015 15 0.037 0.032 0.0271 10/03/91 L016 16 0.053 0.044 0.0312 11/21/91 L016 16 0.025 0.019 0.0123 12/12/91 L016 16 0.020 0.020 0.0146 03/10/92 L016 16 0.018 0.016 0.0127 06/23/92 L016 16 0.021 0.024 0.0168 07/09/92 L016 16 0.029 0.029 0.0139 08/21/92 L016 16 0.026 0.028 0.0111 10/17/91 L017 17 0.003 0.002 0.0031 10/10/91 L018 18 0.006 0.008 0.0012 11/21/91 L018 18 0.002 0.001 0.0023 12/12/91 L018 18 0.012 0.006 0.0024 01/30/92 L018 18 0.002 0.002 0.0035 02/27/92 L018 18 0.003 0.004 0.0026 03/11/92L018 18 0.004 0.004 0.0027 06/23/92 L018 18 0.006 0.004 0.0021 10/17/91 L019 19 0.002 0.003 0.0022 11/21/91 L019 19 0.011 0.003 0.0033 12/12/91 L019 19 0.022 0.002 0.0021 10/17/91 L020 20 0.002 0.003 0.0042 11/21/91 L020 20 0.003 0.006 0.0036 03/10/92 L020 20 0.004 0.006 0.0027 06/23/92 L020 20 0.006 0.007 0.0031 10/10/91 L021 21 0.012 0.004 0.0092 11/21/91 L021 21 0.001 0.001 0.0123 12/12/91 L021 21 0.002 0.002 0.0021 10/03/91 L022 22 0.021 0.022 0.022.2 11/21/91 L022 22 0.005 0.008 0.0076 03/11/92 L022 22 0.006 0.008 0.0057 06/23/92 L022 22 0.006 0.008 0.004



PERIOD DATE11123131234567891234567123456779131677911212341

10/17/9110/10/9110/10/9111/21/9112/12/9110/17/9112/12/9110/10/9111/21/9112/12/9101/30/9202/27/9203/11/9206/23/9207/09/9208/21/9210/17/9111/21/9112/12/9101/30/9202/27/9203/11/9206/23/9210/17/9111/21/9112/12/9101/30/9202/27/9203/10/9206/23/9206/09/9208/21/9210/03/9112/12/9110/17/9103/10/9206/23/9206/28/9208/21/9210/17/9110/10/9111/21/9110/03/9111/21/9112/12/9101/23/9210/10/91

NO house PB1 PB2 PB3L023L025L026L026L026L027L027L029L029L029L029L029L029L029L029L029L031L031L031L031L031L031L031L033L033L033L033L033L033L033L033L033L034L034L035L035L035L035L035L037L038L038L039L039L039L039L040

2324252525262627272727272727272728282828282828292929292929292929303031313131313233333434343435

0.0040.0160.0400.0390.0080.0150.0120.0280.0220.0270.0170.0070.0080.0040.0140.0130.0160.0040.0040.0030.0090.0080.0040.0040.0020.0070.0030.0050.0060.0030.0080.0090.0310.0030.0340.0060.0090.0080.0070.0080.0030.0030.0090.0010.0020.0060.013

0.0030.0150.0170.0230.0030.0140.0210.0390.0210.0140.0160.0100.0100.0150.0190.0170.0070.0050.0030.0040.0050.0120.0020.0030.0020.0020.0030.0050.0050.0020.0110.0130.0210.0050.0310.0040.0160.0100.0090.0010.0030.0050.0160.0010.0080.0060.011

0.0020.0280.0170.0320.0020.0150.0260.0520.0210.0160.0130.0070.0060.0160.0050.0040.0190.0010.0020.0030.0050.0060.0020.0020.0010.0040.0020.0110.0040.0020.0030.0020.0320.0030.0130.0020.0050.0020.0020.0050.0070.0020.0070.0010.0020.0030.001



PERIOD DATE NO house PB1 PB2 PB32 11/21/91 L040 35 0.008 0.004 0.0023 12/12/91 L040 35 0.013 0.002 0.0044 01/30/92L040 35 0.009 0.004 0.0055 02/27/92 L040 35 0.016 0.016 0.0126 03/10/92 L040 35 0.008 0.006 0.0047 06/23/92 L040 35 0.006 0.008 0.0031 10/17/91 L041 36 0.004 0.002 0.0022 11/21/91 L041 36 0.002 0.003 0.0023 12/12/91 L041 36 0.002 0.005 0.0035 02/27/92 L041 36 0.003 0.003 0.0036 03/11/92 L041 36 0.012 0.008 0.0087 06/23/92 L041 36 0.009 0.011 0.0058 07/09/92 L041 36 0.007 0.009 0.0059 08/21/92 L041 36 0.011 0.014 0.0041 10/10/91 L042 37 0.003 0.001 0.0032 11/21/91 L042 37 0.001 0.001 0.0013 12/12/91 L042 37 0.002 0.008 0.0024 01/30/92 L042 37 0.004 0.005 0.0046 03/11/92L042 37 0.004 0.004 0.0037 06/23/92 L042 37 0.006 0.004 0.0048 07/09/92 L042 37 0.007 0.008 0.0039 08/21/92 L042 37 0.006 0.008 0.0021 10/17/91 L043 38 0.021 0.021 0.0203 12/12/91 L043 38 0.002 0.002 0.0021 10/10/91 L044 39 0.012 0.003 0.0042 11/21/91 L044 39 0.014 0.017 0.0101 10/17/91 L045 40 0.010 0.002 0.0012 11/21/91 L045 40 0.001 0.001 0.0013 12/12/91 L045 40 0.004 0.004 0.0034 01/30/92 L045 40 0.002 0.003 0.0046 03/13/92 L045 40 0.005 0.005 0.0047 06/23/92 L045 40 0.006 0.008 0.0037 06/09/92 L045 40 0.008 0.006 0.0049 08/21/92 L045 40 0.012 0.015 0.0041 10/10/91 L047 41 0.004 0.006 0.0081 10/03/91 L048 42 0.012 0.008 0.0151 10/10/91 L049 43 0.014 0.001 0.0062 11/21/91 L049 43 0.002 0.003 0.0016 03/16/92 L050 44 0.004 0.004 0.0027 06/23/92 L050 44 0.004 0.005 0.0021 10/03/91 L051 45 0.011 0.028 0.0136 03/19/92 L051 45 0.010 0.006 0.0047 06/23/92 L051 45 0.002 0.002 0.0024 01/12/92 LC001 46 0.009 0.011 0.0105 02/06/92 LC001 46 0.009 0.013 0.0116 03/16/92 LC001 46 0.012 0.014 0.0117 06/13/92 LC001 46 0.013 0.014 0.009



PERIOD DATE89367893567993673678935678926789367895678935678

07/24/9208/21/9212/19/9103/16/9206/24/9207/13/9208/21/9212/19/9102/06/9203/16/9206/24/9208/21/9209/26/9212/19/9103/03/9206/24/9212/19/9103/03/9206/24/9207/13/9208/21/9212/19/9102/06/9203/16/9206/24/9207/13/9208/26/9211/07/9103/03/9206/24/9207/15/9208/26/9212/19/9103/18/9206/24/9207/15/9208/26/9202/06/9203/03/9206/24/9207/15/9208/26/9212/19/9102/06/9203/06/9206/24/9207/15/92

NO house PB1 PB2 PB3LC001LC001LC002LC002LC002LC002LC002LC003LC003LC003LC003LC003LC003LC004LC004LC004LC005LC006LC006LC006LC006LC007LC007LC007LC007LC007LC007LC009LC009LC009LC009LC009LC010LC010LC010LC010LC010LC011LC011LC011LC011LC011LC012LC012LC012LC012LC012

4646474747474748484848484849494950515151515252525252525353535353545454545455555555555656565656

0.0050.0150.0140.0090.0170.0100.0110.0110.0070.0160.0180.0130.0050.0060.0060.0060.0070.0070.0100.0110.0130.0030.0190.0060.0270.0070.0090.0040.0180.0200.0180.0210.0040.0130.0050.0110.0150.0190.0060.0050.0080.0100.0040.0060.0060.0070.009

0.0030.0190.0100.0120.0190.0130.0140.0090.0080.0120.0130.0180.0480.0040.0080.0080.0100.0080.0110.0100.0170.0030.0160.0040.0080.0090.0120.0020.0150.0250.0150.0230.0030.0140.0020.0150.0190.0140.0040.0070.0080.0140.0040.0040.0080.0030.010

0.0020.0070.0070.0120.0090.0080.0050.0040.0050.0060.0110.0060.0020.0040.0050.0060.0060.0050.0050.0050.0030.0030.0170.0040.0030.0050.0040.0010.0120.0040.0110.0090.0020.0110.0030.0080.0060.0100.0030.0030.0040.0030.0030.0040.0040.0040.004


Fort Worth Water DepartmentLead Service Sites

PERIOD DATE NO house PB1 PB2 PB39 08/26/92 LC012 56 0.011 0.015 0.0043 12/19/91 LC013 57 0.008 0.010 0.0056 03/03/92 LC013 57 0.007 0.007 0.0047 06/24/92 LC013 57 0.003 0.009 0.0058 07/15/92LC013 57 0.005 0.006 0.0039 08/26/92 LC013 57 0.007 0.009 0.0026 03/03/92 LC014 58 0.009 0.011 0.0057 06/24/92 LC014 58 0.006 0.008 0.0028 07/15/92LC014 58 0.009 0.009 0.0049 08/26/92 LC014 58 0.011 0.013 0.0023 12/19/91 LC015 59 0.002 0.002 0.0025 02/06/92 LC015 59 0.007 0.007 0.0056 03/06/92 LC015 59 0.007 0.009 0.0047 06/24/92 LC015 59 0.003 0.010 0.0026 03/03/92 LC016 60 0.007 0.006 0.0047 06/24/92 LC016 60 0.009 0.012 0.0068 07/15/92LC016 60 0.008 0.009 0.0029 08/26/92 LC016 60 0.009 0.016 0.0035 02/06/92 LC017 61 0.012 0.009 0.0036 03/03/92 LC017 61 0.010 0.008 0.0037 06/24/92 LC017 61 0.014 0.009 0.0048 07/15/92 LC017 61 0.007 0.007 0.0049 08/26/92 LC017 61 0.012 0.017 0.0053 12/19/91 LC018 62 0.002 0.008 0.0056 03/18/92 LC018 62 0.012 0.010 0.0057 06/24/92 LC018 62 0.010 0.011 0.0026 03/03/92 LC019 63 0.006 0.008 0.0047 06/24/92 LC019 63 0.008 0.010 0.0033 12/19/91 LC020 64 0.010 0.011 0.0065 02/06/92 LC020 64 0.010 0.010 0.0046 03/03/92 LC020 64 0.012 0.014 0.0066 03/06/92 LC020 64 0.010 0.008 0.0047 06/24/92 LC020 64 0.011 0.013 0.0048 07/15/92 LC020 64 0.010 0.006 0.0029 08/26/92 LC020 64 0.013 0.019 0.0063 12/19/91 LC021 65 0.004 0.003 0.0026 03/03/92 LC021 65 0.011 0.008 0.0047 06/24/92 LC021 65 0.010 0.014 0.0053 12/19/91 LC022 66 0.015 0.011 0.0085 02/06/92 LC022 66 0.010 0.008 0.0056 03/03/92 LC022 66 0.010 0.006 0.0047 06/24/92 LC022 66 0.019 0.020 0.0103 12/19/91 LC023 67 0.007 0.009 0.0045 02/06/92 LC023 67 0.007 0.009 0.0036 03/18/92 LC023 67 0.010 0.007 0.0037 06/24/92 LC023 67 0.003 0.002 0.0028 07/15/92 LC023 67 0.006 0.007 0.004



PERIOD DATE93567896735678967893567893678956789567896777897

08/26/9212/19/9102/06/9203/18/9206/24/9207/15/9208/26/9203/03/9206/24/9212/19/9102/06/9203/03/9206/24/9207/15/9208/26/9203/18/9206/24/9207/15/9208/26/9212/19/9102/06/9203/06/9206/24/9207/15/9208/26/9212/19/9103/03/9206/24/9207/20/9208/28/9202/06/9203/19/9206/24/9207/20/9208/28/9202/06/9203/24/9206/24/9207/20/9208/28/9203/04/9206/24/9206/25/9206/24/9207/28/9208/28/9206/24/92

NO house PB1 PB2 PB3LC023LC024LC024LC024LC024LC024LC024LC025LC025LC026LC026LC026LC026LC026LC026LC027LC027LC027LC027LC028LC028LC028LC028LC028LC028LC029LC029LC029LC029LC029LC030LC030LC030LC030LC030LC031LC031LC031LC031LC031LC032LC032LC033LC033LC033LC033LC034

6768686868686869697070707070707171717172727272727273737373737474747474757575757576767777777778

0.0070.0060.0070.0080.0030.0060.0080.0070.0060.0040.0070.0060.0030.0080.0100.0070.0060.0060.0080.0040.0090.0090.0020.0090.0130.0020.0100.0080.0090.0090.0180.0040.0050.0070.0150.0130.0160.0120.0110.0140.0110.0100.0080.0060.0130.0160.005

0.0090.0060.0080.0080.0060.0060.0080.0080.0080.0020.0050.0060.0020.0060.0120.0090.0050.0070.0090.0020.0100.0090.0030.0110.0180.0020.0090.0090.0080.0090.0200.0020.0050.0050.0180.0140.0120.0150.0120.0200.0140.0130.0060.0090.0140.0190.006

0.0030.0030.0030.0040.0040.0040.0050.0020.0020.0020.0020.0020.0070.0020.0030.0020.0020.0030.0020.0020.0040.0030.0020.0030.0050.0020.0020.0020.0020.0020.0080.0020.0020.0020.0050.0060.0040.0060.0050.0060.0050.0060.0040.0030.0040.0050.002


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Portland Water Bureau Home Tap Samples

DATE 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/2*92 07/12/91 0*13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 OS/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/2*92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91 11/15/91 01/10/92 03/13/92 05/29/92 07/12/91 09/13/91

POSITION

2222223333334444445555556666667777778e e a889999991010101010101111111111111212121212121313131313131414

RunningCU1LIT

0.0810.0780.079

0.10.12

0.10.0980.0980.0880.096

0.140.0820.0840.0710.0720.071

0.10.130.29

0.0690.083

0.080.094

1.8

0.11

1.30.160.210.130.120.140.15

0.0660.110.180.140.180.210.130.11

0.0880.110.140.210.140.190.110.110.130.160.12

0.10.110.230.170.240.15

0.20.096

0.781.20.7

10.62

0.50.450.140.12

0.0920.098

0.120.140.16

RunningPB1LIT

0.0020.0010.0020.0030.0010.0010.0010.0020.0010.0020.0010.0020.0010.0010.0010.0010.0010.0010.0030.0010.0010.0010.0010.014

0.001

0.010.0020.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0010.0020.0010.0010.0010.0010.0010.0010.0010.0020.0010.0020.0020.0030.0010.0020.001

0.0950.0120.0490.0030.0010.0050.0040.0010.0010.0010.0010.0010.0010.001

StandingCU2250

0.660.560.650.85

1.10.970.320.510.74

0.80.37

0.80.8

0.690.9

0.8511

1.30.880.880.81

1.10.57

0.91

1.10.91

1.4

0.811

1.31.11.61.31.61.42.7

0.330.930.68

0.90.87

1.10.660.780.530.680.740.86

1.40.860.93

1.21.11.41.2

10.41

0.920.91.20.81.2

0.740.51.11.3

0.961

1.21.21.1

StandingPB250

0.0290.0190.0140.0160.0180.0090.007

0.010.0140.0220.0060.0120.02

0.0180.0130.0110.0130.014

0.020.0090.0010.0210.0330.003

0.025

0.0050.0270.038

0.0180.0250.0270.0080.0040.0080.0060.0050.0120.014

0.030.0490.0380.0130.0130.0120.0170.0130.0120.0120.0160.0170.0120.014

0.010.01

0.0160.0150.0240.011

0.0290.0070.009

0.010.0090.0030.0030.0210.0040.0380.0190.0250.0250.009

StandingCU750

1.71.21.71.81.8

0.910.140.29

0.80.810.16

11.21.21.51.41.41.31.3

0.741.11.11.40.5

1

0.911.41.9

0.881.21.51.81.21.41.61.91.92.4

0.220.950.79

1.10.49

1.21.11.3

0.911.11.1

.4

.7

.1

.2

.4

.3

.7

.21.3

0.68

10.87

1.20.074

0.61.3

0.571.2

.2

.1

.3

.4

.31.5

StandinQPB750

0.0220.0160.0160.0150.0150.0040.0030.0030.0070.0120.0020.0040.0110.0130.0080.0080.0070.0130.0240.0120.014

0.010.0150.003

0.004

0.0040.0110.0090.0080.0060.0050.0070.0070.0130.0130.0170.0120.0120.0020.008

0.010.0070.0030.0040.0060.0070.0070.0040.0010.0060.0120.0130.0110.009

0.010.0110.0180.0230.015

0.0280.002

0.010.0010.0010.0040.0030.0080.0150.0070.0060.0060.0110.004

CalculatedCCU1LIT

1.441.04

1.4371.5621.6250.9250.1850.3450.7850.8070.212

0.951.1

1.0721.35

1.2621.3

1.2251.3

0.7751.0451.0271.3250.517

0.977

0.9571.2771.775

1.1021.3751.6751.175

1.451.5251.8251.7752.4750.2470.9450.762

1.050.5851.1750.991.17

0.8150.995

1.011.2651.625

1.041.132

1.351.25

1.6251.2

1.2250.612

0.980.877

1.20.255

0.751.16

0.5521.1751.2251.0651.225

1.351.275

1.4

CalculatedCPB1LIT

0.0240.0170.0150.0150.0160.0050.0040.0050.0090.0140.0030.0060.0130.0140.0090.0090.0080.0130.0230.0110.0110.0130.0190.003

0.009

0.0040.0150.016

0.0090.01

0.0120.0070.0110.0120.014

0.010.0120.0050.013

0.020.0150.0050.0060.0070.0090.0080.0060.0040.0080.0130.0130.0120.009

0.010.0120.0170.0230.014

0.0280.003

0.010.0030.0030.0040.0030.0110.0120.0150.0090.0110.0140.005


Portland Water Bureau Home Tap Samples

DATE POSITION 11/15/91 14 01/1 0/92 14 03/13/92 1405/29/9207/1 2/9109/13/9111/15/9101/10/9203/13/9205/29/9207/12/9109/13/9111/15/9101/10/9203/13/9205/29/9207/1 2/9109/13/9111/15/9101/10/9203/13/9205/29/9207/12/9109/13/9111/15/9101/10/9203/13/9205/29/9207/1 2/9109/13/9111/15/9101/10/9203/13/9205/29/9207/12/9109/13/9111/15/9101/10/9203/13/9205/29/9207/1 9/9109/13/9111/15/9101/10/9203/13/9205/29/9207/19/9109/13/9111/15/9101/10/9203/13/9205/29/9207/1 9/9109/13/9111/15/9101/10/9203/13/9205/29/9207/19/9109/13/9111/15/9101/10/9203/13/9205/29/9207/19/9109/13/9111/15/9101/10/9203/13/9205/29/9207/1 »9109/13/9111/15/9101/10/9203/13-9205/29/9207/19/9109/13/9111/15/9101/10/92

1415151515151516161616161617171717171718181818181819191919191920202020202021212121212122222222222223232323232324242424242425252525252526262626262627272727

Running CU1LIT

0.140.16

0.0760.0810.085

0.120.061

0.140.110.09

0.0910.19

0.0960.13

0.0860.091

0.120.13

0.0350.0480.0360.0330.0280.043

0.230.16

0.20.2

0.320.30.1

0.160.13

0.0880.11

0.0980.08

0.0880.0530.053

0.10.070.140.21

0.0880.088

0.140.140.12

0.10.14

0.0780.068

0.120.0580.0810.0570.0570.062

0.30.12

10.370.19

0.20.130.210.790.260.390.230.280.110.17

0.0910.11

Running Standing PB1LIT CU2250

0.0020.0020.0010.0010.0020.0010.0010.0010.0010.0010.0010.0010.0020.0020.0010.0010.0020.0020.0010.0010.0010.0010.0010.0010.0020.0020.0020.0020.0020.0020.0010.0020.0020.0010.0010.0010.0010.0010.0010.0010.0010.0010.0020.0030.0010.0010.0020.0020.0010.0010.0010.0010.0010.0010.0010.0030.0020.0010.0020.0190.0020.0230.0050.0030.0030.0030.0050.0390.0040.0050.0080.0040.0010.0020.0010.001

1.41.6

11.31.71.5

0.35.3.1.1.3.4.2.4.1

1.21.6

1.21

0.790.410.97

1.11.61.31.51.81.6

0.851.31.1

0.860.980.87

1.11.3

11.1

11.31.51.6

0.881.11.11.51.31.1

11.21.11.40.9

0.820.740.85

1.21.31.31.1

0.360.130.21

1.41.6

0.150.130.350.22

1.41.31.60.91.4

Standing Standing PB250 CU750

0.0180.0210.0140.0120.0230.0210.0070.0030.0050.0040.0030.0070.0490.0520.0560.0620.025

0.0130.01

0.0080.0020.0070.008

0.010.0190.0250.0190.023

0.120.0090.0070.0650.0620.0850.104

0.210.190.180.14

0.1040.03

0.0320.0190.0220.0190.0220.0310.0310.0210.025

0.020.0030.0750.0540.0590.0420.0080.0090.0250.0190.0060.0010.0040.0190.0070.0030.0030.0060.0070.0230.0170.0420.0180.016

21.41.31.61.81.90.11.41.31.41.31.61.41.6

11.51.21.6

0.590.55

0.660.470.58

1.61.51.7

22

1.70.93

11.1

11

0.951.41.71.31.51.51.51.92.11.11.51.61.61.4

0.970.96

11.11.61.21.1

0.981.2

11.31.41.2

0.440.120.35

0.91.8

0.150.740.99

0.71.31.51.71.11.5

Standing Calculated Calculated PB750 CCU1UIT CPB1LIT

0.0180.0480.0260.0130.0240.0160.0020.0060.0020.0010.0030.0020.0050.0110.0040.005

0.010.0080.0050.006

0.0030.0030.0060.0080.0060.0050.0030.0040.0060.0180.0630.0070.0510.0260.031

0.010.0170.0080.0110.0090.0090.0470.0480.0520.0390.0360.0470.0060.0030.0050.0060.0050.0150.092

0.110.068

0.120.15

0.0930.0170.0250.0090.0020.009

0.010.0380.0040.0480.0540.0240.05

0.0230.0140.0070.009

1.851.45

1.2251.5251.775

1.80.1621.375

1.251.325

1.31.551.351.55

1.0251.425

1.3

0.7420.662

0.5970.595

0.711.6

1.451.651.95

1.9

0.911.075

1.10.9650.9950.93

1.3251.6

1.2251.4

1.3751.45

1.81.9751.045

1.41.4751.5751.3751.0020.971.05

1.11.55

1.1251.030.92

1.1121.05

1.31.3751.1750.42

0.1220.3151.025

1.750.15

0.5870.830.58

1.3251.45

1.6751.05

1.475

0.0180.0410.0230.0130.0240.0170.0030.0050.0030.0020.0030.0030.0160.0210.0170.0190.014

0.0070.007

0.0030.0040.0060.0080.009

0.010.0070.009

0.0430.0490.0070.0540.0350.0440.0330.0650.0530.0530.0420.0330.0430.0440.0440.0350.0320.0410.012

0.010.0090.0110.0090.0120.0880.0960.066

0.10.1140.0720.0190.0230.0080.0020.0080.012

0.030.0040.0370.042

0.020.0430.0210.021

0.010.011

References

ASTM (American Society of Testing and Materials). 1983. Standard Test Methods for Corrosivity of Water in the Absence of Heat Transfer (Weight Loss Methods). ASTM D2688-83. Philadelphia, Pa.: ASTM.

———. 1990. Standard TestMethods for Corrosivity ofWaterin the Absenceof Heat Transfer (Weight Loss Methods). ASTM D2688-90.Philadelphia, Pa.: ASTM.

CDA (Copper Development Association). 1972. Copper Tube Handbook.No. 411/12. Greenwich, Conn.: CDA.

Cohen, Al, and J. Myers. 1987. Mitigating Copper Pitting Through WaterTreatment Jour. AWWA, 77(10):74-82.

D'lppolito, A. 1989. Flushing and Chemically Cleaning New Piping Systems.fa Proc. of the Fiftieth Annual International Water Conference.Pittsburgh, Pa.: Engineers Society of Western Pennsylvania.

EES (Economic and Engineering Services, Inc.). 1988. Greater VancouverRegionalDistrict Water Quality ImprovementPlan—Corrosion ControlInitiative—Phase n. Internal report prepared for Greater VancouverRegional District, Vancouver, B.C.

———. 1990. Lead Control Strategies. Denver, Colo.: AWWA Research Foundation and American Water Works Association.

Federal Register. 1989. 54 FR 14320 (April 10).Heinz, K.D., and J.A. Gray. 1991. Neutral pH Process for On-Line Cleaning

and Passivation of Hot and Chilled Water Systems. In Proc. of the Fifty-Second Annual Water Conference. Pittsburgh, Pa.: Engineering Society of Western Pennsylvania.

Herrera,C.E.,B.P.Hoyt,andGJ.Kirmeyer. 1981-1983. Seattle Distribution System Corrosion Control Study. Volumes 1,2, and 3. EPA Environmental Research Laboratory, Office of Research and Development, Cincinnati, Ohio.

Heuman, David W., and Steven H. Ramberg. 1990. Corrosion Inhibitor Effects on Los Angeles Water Sources. Presented at the Eighteenth Annual AWWA Water Quality Technology Conference. November 11-15,1990. San Diego, Calif.

Karalekas, P.C., Jr., C.R. Ryan, and F.B. Taylor. 1983. Control of Lead, Copper, and Iron Pipe Corrosion in Boston. Jour. AWWA, 75(2):92- 95.

415


Loucks, Charles M. 1968. How to Establish and Maintain Cleanliness ofClosed Piping for Large Building Air Conditioning. Heating, Pipingand Air Conditioning, 40:114-117.

Molnar, W., and E. Haden. 1986. Treated Water Corrosion Inhibition UsingZinc Qrthophosphate. Report prepared for Santa Clara Valley WaterDistrict, Santa Clara, Calif.

Montgomery, James M., Consulting Engineers. 1982. Internal CorrosionMitigation Study, Final Report. Prepared for Portland, Qreg., Bureauof Water Works.

NACE (National Association of Corrosion Engineers). 1980. Prevention andControl of Water-Caused Problems in Building Potable WaterSystems. TPC Publication 7. Houston, Tex.: NACE.

Neff, C.H., and R.W. Lane. 1987. Removal of Deposits From Potable WaterSystems Using Carbon Dioxide. Materials Performance, 26:21-28.

Reiber, S.R. 1989. Copper Plumbing Surfaces: An Electrochemical Study.Jour. AWWA, 81(7): 114-122.

Reiber, S.R., J.F. Ferguson, and M.M. Benjamin. 1986. An InnovativeTechnique for Corrosion Rate Measurements Within the DistributionSystem. In Proc. of the Fourteenth Annual AWWA Water QualityTechnology Conference. Denver, Colo.: AWWA.

————. 1988. Internal Corrosion Within the Everett Distribution System—Draft Report. Preparedfor Utilities Division, Public Works Department,Everett, WA.

Ryder, R.A. 1978. Methods of Evaluating Corrosion. In Proc. of the SixthAnnual AWWA Water Quality Technology Conference. Denver, Colo.:AWWA.

Ryder, R.A., and B. Hoyt. 1977. Corrosion Conditions and Correction ofSeattle's Mountain Pure Water. Paper presented at the AWWAAnnual Conference, Eugene, Oreg.

Schock, M.R. 1980. Response of Lead Solubility to Dissolved Carbonate inDrinking Water. Jour. AWWA, 72(12):1695.

———. 1981. Errata. Jour. AWWA, 73(3):36.Schock, M.R., and M.C. Gardels. 1983. Plumbosolvency Reduction by High

pH and Low Carbonate-Solubility Relationships. Jour. AWWA,75(2):87-91.

Schock, M.R., and C.H. Neff. 1988. Trace Metal Contamination From BrassFittings. Jour. AWWA, 80(ll):47-56.

Temkar, P., K.K. Phull, J.A. Valcik, and T.R. Runyon. 1989. TreatmentEvaluation for Reducing Lead Dissolution From Plumbing SystemsUsing CERL Pipe Loop System. Internal report. Champaign, Dl.: U.S.Army Construction Engineering Research Laboratory.

References 417

Temkar, P., RJ. Schloze, Jr., S.W. Maloney, and C.H. Neff. 1987. Pipe Loop System for Evaluating Effects of Water Quality Control Chemicals in Water Distribution Systems. InProc. of the Fifteenth Annual AWWA Water Quality Technology Conference. Denver, Colo.: AWWA.

Treweek, G.P., J. Glicker, B. Chow, and M. Sprinker. 1985. Pilot-Plant Simulation of Corrosion in Domestic Pipe Materials. Jour. AWWA, 77(10):74.

USEPA (U.S. Environmental Protection Agency). 1991. Drinking Water Regulations; Maximum ContaminantLevel Goals and National Primary Drinking Water Regulations for Lead and Copper; FinalRule. 40 CFR, parts 141 and 142. 56 Federal Register No. 110, June 7,1991.

USEPA. 1992£eadandCopperRule Guidance Manual. Volume II-.Corrosion Control Treatment. Washington, D.C.: USEPA.

Wachter, A., and R.S. Treseder. 1947. Corrosion Testing Evaluation of Metals for Process Equipment Chem. Eng. Progress, 43:316-326.

Abbreviations

ANOVA analysis of varianceASTM American Standards for Testing and

MaterialsAWWA American Water Works Association AWWARF American Water Works Association

Research Foundation

bdl below detection limit bgd billion gallons per day

°CCCWDCERL

degrees Celsius (centigrade) Contra Costa Water District U.S. Army Corps of Engineers'

ConstructionEngineering ResearchLaboratory

CERL-PLS U.S. Army Corps of Engineers'Construction Engineering ResearchLaboratory pipe loop system

cfu colony forming units cm centimeter CPVC chlorinated polyvinyl chloride CT residual disinfectant concentration

(mg/L) x contact time (minutes) cu color unit CV coefficient of variation

d dayD/DBPRule Disinfection/Disinfection By-Products

RuleDBF disinfection by-product DIG dissolved inorganic carbon

EES

fpsft, ft2, ft3ft-lb/sop

g

Economic and Engineering Services, Inc.

feet per second foot, square foot, cubic foot foot-pounds per second degree Fahrenheit

gram

GAC granular activated carbongal gallongpd gallons per daygpm gallons per minuteGVWD Greater Vancouver Water District

h hourHPC heterotrophic plate count

ISWS Illinois State Water SurveyID inside diameteri.e. that isin. inch

kPa kilopascal

L literLADWP Los Angeles Department of Water

and PowerLCCA Lead Contamination Control ActL/min liters per minuteL/s liters per second

m meterm3/d cubic meters per daym3/week cubic meters per weekMCL maximum contaminant levelMCLG maximum contaminant level goalmdd milligrams per square decimeter per

dayug/L micrograms per literumhos/cm micromhosmg milligrammgd million gallons per daymg/L milligrams per litermil gal million gallonsmL millilitermL/min milliters per minutemm millimetermpy mils per yearm/s meters per second

419


NACE National Association of CorrosionEngineers

ntu nephelometric turbidity unit NIWC Northern Illinois Water Corporation

O&M operations and maintenance

PCTS programmable corrosion testingstation

pH negative logarithm of the effectivehydrogen-ion concentration

PRV pressure-reducing valve PTFE generic term for Teflon® psig pounds per square inch gauge PVC polyvinyl chloride

RCH reusable coupon holder

SDWA Safe Drinking Water ActSWTR Surface Water Treatment Rule

TCC total colony countTDS total dissolved solidsTHM trihalomethaneTIC total inorganic carbon

UPS United Parcel ServiceUSEPA U.S. Enviromental Protection AgencyUV ultraviolet

QA-QC Quality assurance-quality control WTP water treatment plant

American Water Works AssociationRESEARCH FOUNDATION

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