executive summary · wastewater facility plan september 2011 table 2-3 lift station no. 1...

City of Mabton ES-1

General Sewer Plan and Wastewater Facility Plan September 2011

EXECUTIVE SUMMARY

The City of Mabton’s Wastewater Facility Plan provides a 20-year plan for maintaining

adequate capacity at the City’s Wastewater Treatment Facility (WWTF). This Plan has

been prepared in accordance with the Washington State Department of Ecology’s

guidelines set forth in WAC 173-240-060.

The Plan achieves the following objectives:

Projects future wastewater service area population

Develops design wastewater flows and loadings

Describes the condition of existing treatment facilities

Determines required capital improvements

Presents a capital improvements financing plan, including potential sewer rate

impacts

PROJECTED WASTEWATER FLOWS AND LOADINGS

Projected wastewater flows and loadings to the WWTF for the design year 2031 are based

on historical flows and loadings and growth projections for the sewer service area. These

projections assume that the population in City’s service area will grow at 1.5 percent per

year during the next 20 years, from a current population of 2,165 to a future population of

3,031 in 2031. This is the City’s high forecast growth rate identified in the City’s 2009

Comprehensive Plan Update and is based on the City’s goals and policies.

The estimated 2031 flows and loadings for the future population are shown in Table

ES-1.

TABLE ES-1

2031 Projected Design Wastewater Flows and Loadings

Flow or Loading Projected Design Value

Sewer Service Population

3,031

Average Annual Flow (MGD) 0.24

Maximum Month Flow (MGD) 0.29

Maximum Day Flow (MGD) 0.69

Peak Hour Flow (MGD) 0.87

Annual Average BOD5 Loading (lb/d) 515

Maximum Month BOD5 Loading (lb/d) 697

Annual Average TSS Loading (lb/d) 455

Maximum Month TSS Loading (lb/d) 727

Maximum Month TKN Loading (lb/d) 155

Gray & Osborne, Inc., Consulting Engineers

ES-2 City of Mabton

September 2011 General Sewer Plan and Wastewater Facility Plan

PERMIT REQUIREMENTS

The WWTF discharges to the lower Yakima River. The lower Yakima River in the

vicinity of the City WWTF outfall has been listed on the Department of Ecology’s 303(d)

list of impaired water bodies because the ambient river conditions for temperature, fecal

coliform, dissolved oxygen, and pesticide concentrations are greater than the water

quality standards.. Recently, phosphorus has been measured at levels of concern in the

lower Yakima River.

In the future, Yakima River Total Maximum Daily Load (TMDL) may be established for,

fecal coliform bacteria, dissolved oxygen, and temperature. Department of Ecology has

already completed a TMDL for pesticides that does not affect the WWTF permit.

Department of Ecology has stated that it is possible that phosphorus will be added to the

list of items requiring TMDL.

Table ES-2 presents the projected effluent permit limits for the City’s WWTF based on

the water quality study completed in Appendix C..

TABLE ES-2

City of Mabton WWTF

Future Projected NPDES Permit Effluent Limits

Parameter Maximum Daily Average Monthly Average Weekly

BOD5 N/A

10 mg/L, 24.2 lb/day,

85% removal of

influent BOD

15 mg/L, 40.7

lb/day

TSS N/A

30 mg/L, 72.6 lb/day,

85% removal of

influent TSS

45 mg/L, 122

lb/day

Fecal Coliform N/A 100 per 100 mL 200 per 100 mL

pH Daily minimum is equal to or greater than 6 and the daily

maximum is less than or equal to 9

Dissolved Oxygen 3 mg/L (minimum) 4 mg/L (minimum) N/A

Total Ammonia

(as NH3-N) 4.5 mg/L 2.9 mg/L N/A

The future projected permit limits will lower the total ammonia limit by 85 percent over

the existing permit limits from 20 mg/L to 2.9 mg/L. This will require nitrification to

ensure that the ammonia is converted to nitrates.

The BOD5 monthly limit was lowered during the last permit cycle from 30 mg/L to 10

mg/L to meet water quality standards. Even though the WWTF has been meeting the 10


City of Mabton ES-3


mg/L limit, the existing WWTF was never designed to meet this limit. This low limit

will require that selected alternative provide methods to create good settling solids and

the clarifiers needs to meet current permit requirements.

The City realizes the importance of planning for future limits. Potential future limits

include nitrogen and phosphorus because of the low oxygen level in the lower Yakima

River. In October 2008, Ecology received funding from the Environmental Protection

Agency to conduct an evaluation of nutrient removal technologies at municipal WWTFs

across the State of Washington. This nutrient removal study is being performed to

identify the technical and economic issues related to the removal of nitrogen and

phosphorus from WWTF effluent. Ecology permit managers are encouraging all cities to

consider nutrient removal as part of the planning process.

This Plan evaluated methods to increase effluent dissolved oxygen, lower effluent

temperature, and nitrogen removal in preparation of future permit limits. The Plan will

not evaluate methods to remove phosphorus because phosphorus has not been added to

the items requiring a TMDL. Therefore any requirement to remove phosphorus is not

anticipated for a minimum of 10 to 15 years based on conversations with Ecology.

However, the selected WWTF improvement can be upgraded in the future to remove

phosphorus.

COLLECTION SYSTEM

The existing collection system consists of approximately 8-miles of gravity sewer and one

lift station. Most of the sewers pipes in the City are concrete. The majority of the sewers

are at least 65-years old and were constructed in 1954. There are no recent videos of the

sewers; therefore, the condition of the sewers is unknown. There are no reported sewer

failures, but some of the sewers could be reaching the end of their useful life.

Department of Ecology has recommended an infiltration and inflow study of the sewers

to determine the condition of the existing collection system. An infiltration and inflow

study would include video recording of the collection system to determine the structural

integrity of the pipes. The estimated cost of the infiltration and inflow study is $55,000.

WASTEWATER TREATMENT FACILITY

An evaluation of the WWTF determined the following.

The WWTF is at 85 percent of design capacity and the City is required to plan for

upgrades to the WWTF.

A significant portion of the WWTF components do not have sufficient capacity

for the projected future population.

Several unit processes are functionally obsolete and are required to be replaced to

reliably meet the permit limits.


ES-4 City of Mabton

September 2011 General Sewer Plan and Wastewater Facility Plan

Process upgrades are required to ensure that the low ammonia discharge limit is

reliability meet by nitrification.

It was determined that the removal of nitrogen by denitrification is the most cost

effective method to prevent permit violations for low pH.

Effluent aeration is required to meet the permit limits for effluent oxygen.

The mixing zone study determined that cooling of the effluent is not required

because the river temperature rise is less than 0.3 ºC.

Figure ES-1 presents the results of the WWTF evaluation.

RECOMMENDED IMPROVEMENTS

It was determined that the following improvements are recomended:

An Infiltration and Inflow (I&I) Study to assess the condition of the sewer

collection system. The estimated cost of the I&I study is $55,000

Phase 1 WWTF Improvement Project which consists of upgrading the existing

mechanical wastewater treatment facility to reliably meet the NPDES permit and

to increase the capacity of the WWTF. The estimated cost of the Phase 1 project

is $5,683,000 and the estimated operation and maintenance annual cost is

$270,000. Phase 1 will require the purchase of at least 4-acres.

Future Phase 2 WWTF Improvement Project which consists of a natural treatment

polishing process. The purpose of the natural treatment polishing process is

environmental enhancement for fisheries and wildlife, environmental education

and economic development. This wetland may also be utilized for future storm

water treatment for the City or be constructed for wetland mitigation banking.

Funding sources and cost estimates for Phase 2 WWTF Improvement will be

further evaluated during the predesign report for Phase 1. This project will

require the purchase of at least 10 acres of land.

Figure ES-2 presents the capital improvements required for Phase 1.

FINANCING AND RATES

The I&I study will be financed from the sewer system reserves.

The City has received two sources of financing for the Phase 1 improvements. The first

is a $600,000 legislative grant from the State of Washington. The City has also been

placed on the offer list for a PWTF loan which will finance the remaining portion of the

project. The City intends to apply for the Department of Ecology SRF/CCWF programs

in the fall in case the state defunds the PWTF loan program during the next legislative

session.


City of Mabton ES-5


The estimated sewer rates for the City with the legislative grant and the PWTF loan is in

the range of $65 to $70 per month. If the City can receive additional grants the sewer

rates can be reduced by approximately $5 for each $1.0 million in grant funding. In

addition, the City will apply for the CDBG grant program to try to lower the sewer rates.

i

TABLE OF CONTENTS

CITY OF MABTON

WASTEWATER FACILITY PLAN

CHAPTER 1: INTRODUCTION

BACKGROUND ............................................................................................... 1-1

OVERVIEW .................................................................................................... 1-1

HISTORY AND DEVELOPMENT OF THE SEWER SYSTEM ................................. 1-2

REVIEW OF EXISTING REPORTS ..................................................................... 1-2

SCOPE ........................................................................................................... 1-3

CHAPTER 2: PLANNING CONSIDERATIONS

INTRODUCTION ............................................................................................. 2-1

PLANNING PERIOD ........................................................................................ 2-1

SERVICE AREA .............................................................................................. 2-1 PROJECTED SERVICE AREA ................................................................................... 2-1

LAND USE AND ZONING ................................................................................ 2-1

SERVICE AREA POPULATION ......................................................................... 2-2

COLLECTION SYSTEM ................................................................................... 2-4

ENVIRONMENTAL FACTORS .......................................................................... 2-5 CLIMATE ............................................................................................................... 2-5

PHYSIOGRAPHY ..................................................................................................... 2-5

GEOLOGY .............................................................................................................. 2-6

SEISMIC HAZARD .................................................................................................. 2-7

VOLCANIC HAZARD .............................................................................................. 2-7

SOILS .................................................................................................................... 2-8

WETLANDS ........................................................................................................... 2-8

SURFACE WATER .......................................................................................... 2-8

WATER SUPPLY ............................................................................................. 2-9

GROUNDWATER ............................................................................................ 2-9

ENVIRONMENTAL REVIEW .......................................................................... 2-10

TREATMENT FACILITIES SITING .................................................................. 2-10

CHAPTER 3: REGULATORY REQUIREMENTS

INTRODUCTION ............................................................................................. 3-1

WATER QUALITY STANDARDS FOR SURFACE WATERS OF THE STATE OF

WASHINGTON, CHAPTER 173-201A WAC .................................................... 3-1 WATER QUALITY CLASSIFICATION ....................................................................... 3-1

ii

CHAPTER 3: REGULATORY REQUIREMENTS - CONTINUED

MIXING ZONES .............................................................................................. 3-2

ANTI-DEGRADING ......................................................................................... 3-4

TOTAL MAXIMUM DAILY LOAD (TMDL) ..................................................... 3-5

DISCHARGE PERMITS .................................................................................... 3-5

STATE OF WASHINGTON WWTF PLANNING REGULATIONS WAC 173-240 . 3-6

STATE OF WASHINGTON BIOSOLIDS REGULATIONS WAC 173-308 .............. 3-6

OTHER REGULATORY REQUIREMENTS .......................................................... 3-6 NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) ............................................. 3-6

STATE ENVIRONMENTAL POLICY ACT (SEPA) ..................................................... 3-7

ARCHEOLOGICAL AND CULTURAL RESOURCES SURVEY....................................... 3-7

REGULATORY REQUIREMENTS FOR SHORELINE PERMITTING IN THE STATE OF

WASHINGTON ....................................................................................................... 3-7

JOINT AQUATIC RESOURCES PERMIT APPLICATION (JARPA) .............................. 3-7

REGULATORY REQUIREMENTS FOR STORMWATER PERMITTING IN THE STATE OF

WASHINGTON ....................................................................................................... 3-8

YAKIMA COUNTY CODES ...................................................................................... 3-8

REGULATORY SUMMARY .............................................................................. 3-9

CHAPTER 4: WASTEWATER FLOWS AND LOADINGS INTRODUCTION ............................................................................................. 4-1

HISTORICAL WASTEWATER FLOWS............................................................... 4-1

PEAK HOUR FLOW ........................................................................................ 4-4

DEFINITION OF INFILTRATION ....................................................................... 4-4

DEFINITION OF INFLOW ................................................................................. 4-4

I/I FLOW CRITERIA ........................................................................................ 4-5

HISTORICAL LOADINGS ................................................................................. 4-5

NITROGEN LOADING .................................................................................................... 4-7

SUMMARY OF PROJECTED WASTEWATER FLOW AND LOADINGS .................. 4-7

CHAPTER 5: WWTF EVALUATION

GENERAL ...................................................................................................... 5-1

PROJECTED WASTEWATER FLOWS AND LOADINGS ....................................... 5-1

FUTURE PERMIT LIMITS ................................................................................ 5-2

EXISTING OPERATION ................................................................................... 5-3

SEWER COLLECTION SYSTEM ....................................................................... 5-3

LIFT STATION NO. 1 ........................................................................................... 5-4

INTERCEPTOR SEWER ....................................................................................... 5-4

COLLECTION SYSTEM ....................................................................................... 5-5

WASTEWATER TREATMENT FACILITY (WWTF) ........................................... 5-5

HEADWORKS ...................................................................................................... 5-5

iii

CHAPTER 5: WWTF EVALUATION - CONTINUED

SEWAGE CONDITIONING TANK ....................................................................... 5-6

OXIDATION DITCH ............................................................................................. 5-6

SECONDARY CLARIFIERS ............................................................................... 5-13

RETURN AND WASTE ACTIVATED SLUDGE SYSTEM .................................. 5-14

DISINFECTION .................................................................................................. 5-16

EFFLUENT PUMP STATION .............................................................................. 5-17

OUTFALL ........................................................................................................... 5-17

SOLIDS TREATMENT FACILITIES.................................................................. 5-18

AEROBIC SLUDGE STORAGE TANK ............................................................... 5-18

SLUDGE DRYING BEDS .................................................................................... 5-20

ELECTRICAL SERVICE ..................................................................................... 5-21

SCADA SYSTEM ................................................................................................ 5-21

LAB AND MAINTENANCE BUILDING ............................................................. 5-22

NONPOTABLE WATER SYSTEM ...................................................................... 5-22

SUMMARY OF EXISITNG FACILITIES ............................................................ 5-22

CHAPTER 6: WASTEWATER TREATMENT FACILITY

IMPROVEMENTS

INTRODUCTION ............................................................................................. 6-1

COLLECTION SYSTEM IMPROVEMENTS ......................................................... 6-1

WWTF IMPROVEMENT ALTERNATIVE .......................................................... 6-1

BIOLOGICAL TREATMENT ............................................................................. 6-3

ULTRAVIOLET DISINFECTION SYSTEM ........................................................ 6-22

NONPOTABLE WATER SYSTEM ................................................................... 6-25

ELECTRICAL SERVICE ................................................................................. 6-26

LAB AND MAINTENANCE BUILDING ........................................................... 6-27

SCADA SYSTEM ........................................................................................ 6-27

SOLIDS HANDLING ...................................................................................... 6-27

CHAPTER 7: WATER RECLAMATION AND REUSE

EVALUATION

ALLOWABLE USES FOR RECLAIMED WATER ................................................. 7-1

REUSE EVALUATION ..................................................................................... 7-2

COST EFFECTIVENESS ................................................................................... 7-2

REGULATORY REQUIREMENTS ...................................................................... 7-3

WATER RIGHTS ............................................................................................. 7-3

SUMMARY ..................................................................................................... 7-3

iv

CHAPTER 8: FINANCING

INTRODUCTION ............................................................................................. 8-1

EXISTING SERVICE RATES AND CONNECTION CHARGES ............................... 8-1

HISTORICAL OPERATIONS ............................................................................. 8-1

CAPITAL IMPROVEMENT PROGRAM ............................................................... 8-3

FINANCING OPTIONS ..................................................................................... 8-4

PUBLIC WORKS TRUST FUND ........................................................................... 8-4

USDA RURAL DEVELOPMENT .......................................................................... 8-5

STATE REVOLVING FUND/CENTENNIAL CLEAN WATER FUND .................. 8-5

STATE AND TRIBAL ASSISTANCE GRANTS .................................................... 8-6

COMMUNITY ECONOMIC REVITALIZATION BOARD ..................................... 8-6

UTILITY LOCAL IMPROVEMENT DISTRICTS ................................................... 8-7

GENERAL OBLIGATION BONDS........................................................................ 8-8

LIST OF TABLES

No. Page

2-1 City of Mabton Projected Population .................................................................. 2-4

2-2 Collection System Inventory................................................................................ 2-4

2-3 Lift Station No. 1 Information ............................................................................. 2-5

2-4 Monthly Climate Summary.................................................................................. 2-5

3-1 Water Quality Criteria Yakima River at Mabton Outfall .................................... 3-2

3-2 Results of Receiving Water Sampling and Analysis ........................................... 3-2

3-3 Outfall Dilution Factors at Currently Permitted Design Flows ........................... 3-3

3-4 Modeling Parameters ........................................................................................... 3-4

3-5 City of Mabton Final Effluent Limitations .......................................................... 3-6

3-6 Summary Regulatory Requirements .................................................................... 3-9

4-1 Historical WWTF Influent Flows ........................................................................ 4-3

4-2 Historical WWTF Influent Flows per Capita....................................................... 4-4

4-3 Historical WWTF Influent Loadings ................................................................... 4-6

4-4 Historical WWTF Influent Loading per Capita ................................................... 4-7

4-5 2031 Projected Design Wastewater Flows and Loadings .................................... 4-8

5-1 2031 Projected Design Wastewater Flows and Loadings .................................... 5-1

5-2 Future Projected NPDES Permit Effluent Limits ................................................ 5-2

5-3 Headworks Design Criteria .................................................................................. 5-5

5-4 Sewage Conditioning Tank Design Criteria ........................................................ 5-7

5-5 Oxidation Ditch Design Criteria .......................................................................... 5-8

5-6 Secondary Clarifier Design Criteria ................................................................... 5-13

5-7 RAS/WAS Pumping System Design Criteria .................................................... 5-15

5-8 UV Disinfection System Design Criteria ........................................................... 5-16

5-9 Effluent Pump System Design Criteria .............................................................. 5-17

5-10 Aerobic Sludge Storage System Design Criteria ............................................... 5-18

v

LIST OF TABLES – continued

No. Page

6-1 Headworks Design Criteria .................................................................................. 6-3

6-2 Alternative Operation and Maintenance Cost ...................................................... 6-7

6-3 Alternative Capital and Present Worth Cost ........................................................ 6-7

6-4 Design Criteria Biological Treatment ................................................................ 6-17

6-5 Design Criteria Secondary Clarifier................................................................... 6-19

6-6 UV System Design Criteria ............................................................................... 6-20

6-7 Effluent Pumping System Design Criteria ......................................................... 6-20

6-8 Effluent Aeration Design Criteria ...................................................................... 6-21

6-9 Nonpotable Water System Design Criteria ........................................................ 6-23

6-10 Cost Comparison Solids Handling ..................................................................... 6-26

6-11 Sludge Handling Design Criteria ....................................................................... 6-27

8-1 Sewer Service Base Rates .................................................................................... 8-1

8-2 Historical Revenues and Expenditures ................................................................ 8-2

8-3 Alternative Cost – Capital and Operation and Maintenance Cost ....................... 8-3

8-4 Sewer Rate Projection for the WWTF Improvements ......................................... 8-4

8-5 Funding Program Application Submittal Schedules ............................................ 8-4

8-6 Ecology Grant/Loan Hardship Funding ............................................................... 8-6

LIST OF FIGURES

No. Figure On or Follows Page

1-1 Location Map ....................................................................................................... 1-2

2-1 Service Area ......................................................................................................... 2-2

2-2 Zoning Map .......................................................................................................... 2-2

2-3 City of Mabton Historical Population .................................................................. 2-2

2-4 Comprehensive Plan Population Projections ...................................................... 2-3

2-5 Sewer Map ........................................................................................................... 2-4

2-6 Flood Map ............................................................................................................ 2-6

4-1 Historical WWTF Monthly Average Influent Flows ........................................... 4-2

4-2 Historic WWTF Daily Influent Flows ................................................................. 4-3

4-3 Historical WWTRF Influent Loadings ................................................................ 4-6

5-1 Schematic Flow Diagram ..................................................................................... 5-4

5-2 Existing Hydraulic Profile ................................................................................... 5-4

5-3 Existing WWTF Plan ........................................................................................... 5-4

5-4 Capacity Analysis .............................................................................................. 5-24

6-1 Biological Treatment Alternative 1 ..................................................................... 6-4





vi


6-7 Diagger Roper Curve ......................................................................................... 6-20

6-8 Proposed Hydraulic Profile ................................................................................ 6-29

6-9 Sludge Drying Bed Alternative .......................................................................... 6-29

6-10 Mechanical Dewatering Alternative .................................................................. 6-29

APPENDICES

Appendix A – NPDES Permits

Appendix B – DMR Data Summary

Appendix C – Water Quality Evaluation

Appendix D – Cost Estimates

Appendix E – Environmental Reports SEPA

Appendix F – Mabton Green Projects Water & Energy Efficiency Alternatives Study

LIST OF ABBREVIATIONS AAF average annual flow ac acre ACOE Army Corps of Engineers ADWF average dry weather flow AKART all known, available, and reasonable technologies avg. average BOD5 5-day biochemical oxygen demand BTU British thermal units CaCO3 calcium carbonate CBOD5 5-day carbonaceous biochemical oxygen demand CCWF Centennial Clean Water Fund CF cubic feet cfm cubic feet per minute CFR Code of Federal Regulations cfs cubic feet per second cfu colony forming units CIP Capital Improvement Projects CM construction management CMU concrete masonry units COD chemical oxygen demand conc. concentration constr. construction CWA Clean Water Act CWCOG Cowlitz-Wahkiakum Council of Governments cy cubic yards DMR discharge monitoring reports DNS determination of non-significance DO dissolved oxygen DOH Department of Health DT dry tons EA each EIS Environmental Impact Statement EPA Environmental Protection Agency ERU equivalent residential unit ESA Endangered Species Act FEMA Federal Emergency Management Agency FIRM Flood Insurance Rate Maps F/M food to microorganism ratio ft2 square feet ft/sec feet per second FTE full time equivalent gal. gallons gfd gallons per square foot per day

LIST OF ABBREVIATIONS (CONT.) GMA Growth Management Act gpad gallons per acre per day gpcd gallons per capita per day gpd gallons per day gpd/ft2 gallons per day per square foot gph gallons per hour gpm gallons per minute gpm/ft2 gallons per minute per square foot HDPE high density polyethylene HMI Human-Machine Interface hp horsepower HPA Hydraulic Project Approval HRT hydraulic residence time HVAC heating, ventilation, and air conditioning I/I infiltration and inflow in. inches kVA kilovolt-amps kW kilowatt kWh kilowatt hour lb pounds lb/cap/day pounds per capita per day lb/d pounds per day lb/day pounds per day lb/ft2/day pounds per square foot per day lf linear foot LS lump sum max. maximum MBR membrane bioreactor MDF maximum day flow mg milligrams MG million gallons mgd million gallons per day mg/L milligrams per liter misc. miscellaneous mJ/cm2 millijoules per square centimeter (UV dose measurement) mL milliliters MLSS mixed liquor suspended solids mm millimeter MM maximum month MMF maximum month flow MSL mean sea level N/A not applicable NEPA National Environmental Policy Act

LIST OF ABBREVIATIONS (CONT.) NH3 ammonia-nitrogen NMFS National Marine Fisheries Service NO3-N nitrate - nitrogen NPDES National Pollutant Discharge Elimination System NR not reported NRCS National Resource Conservation Service NTU nephelometric turbidity units NWI National Wetlands Inventory OD outside diameter OFM Office of Financial management O&M operations and maintenance PDF peak day flow PFRP process to further reduce pathogens pH negative log hydronium ion concentration PHF peak hour flow PHS priority habitat and species PLC Programmable Logic Controller PMAC plan to maintain adequate capacity P.S. pump station psi pounds per square inch PSRP process to significantly reduce pathogens PWTF Public Works Trust Fund Q flow rate RAS return activated sludge RCW Revised Code of Washington ROW right-of-way rpm revolutions per minute SBR sequencing batch reactor scfm standard cubic feet per minute SEPA State Environmental Policy Act SERP State Environment Review Process sf square feet S.F. safety factor SR State Route SRF State Revolving Fund SRT solids retention time SWD side water depth TBD to be determined TDH total dynamic head TKN total Kjehldahl nitrogen TMDL total maximum daily load TSS total suspended solids UGA Urban Growth Area

LIST OF ABBREVIATIONS (CONT.) USFWS United States Fish and Wildlife Service USGS United States Geologic Survey UV Ultraviolet Radiation V volts VFD variable frequency drive VOC volatile organic compounds VS volatile solids VSS volatile suspended solids WAC Washington Administrative Code WAS waste activated sludge WDFW Washington Department of Fish and Wildlife WT wet tons WWTP wastewater treatment plant µm micrometer (micron)

CHAPTER 1

INTRODUCTION

City of Mabton 1-1

Wastewater Facility Plan September 2011

CHAPTER 1

INTRODUCTION

BACKGROUND

This Wastewater Facility Plan (Plan) addresses the City’s comprehensive planning needs

for wastewater treatment, and disposal for the next 20 years. This Plan has been prepared

in accordance with the provisions of the Revised Code of Washington (RCW), at Section

90.48, Water Pollution Control, Washington Administrative Code (WAC) Section WAC

173-240-060, Engineering Report, and the United States Code of Federal Regulations

(CFR) at 40 CFR 35.917, Facilities Planning. Development of the Plan has been

coordinated with the City’s 2009 Comprehensive Plan Update.

The Plan is intended to be feasible in terms of engineering, economic, regulatory, and

political frameworks. Included in the Plan are conceptual layouts and cost estimates for

recommended major improvements to facilities, as well as a proposed schedule for

construction and a financing plan. The projects described in the Plan are consistent with

State regulations relating to the prevention and control of pollutants discharged into State

waters, anti-degradation of existing and future beneficial uses of ground waters, and anti-

degradation of surface waters. The Plan will have sufficient flexibility to provide

wastewater facilities for existing areas of need and to support future development within

the planning area.

OVERVIEW

The City of Mabton is located near the Yakima River in southeast Yakima County as

shown on Figure 1-1. The City is approximately 40 miles southeast of the county seat of

Yakima. Unincorporated Yakima County surrounds the City on all sides. The Yakama

Nation borders the City to the west. Neither the City nor its urban growth area (UGA) is

in the Yakima Nation boundaries. The nearest cities are Sunnyside eight miles north and

Grandview seven miles to the northeast.

The current city limits constitute an area of approximately 525 acres with an UGA of

approximately 578 acres. The current City population for 2010 is 2,165 people. The

mayor discharger of wastewater in the City is the schools. The nursery with greenhouses

is a large industry in the City. The nursery is a large water user for irrigation but this

water is not discharged to the sewer system.

A Mayor and City Council govern the City of Mabton. The City owns and operates the

municipal sewer collection system and the Wastewater Treatment Facility (WWTF),

which discharges to the Yakima River. The collection system serves the residents,

businesses, commercial and public facilities within the city limits. The WWTF operator


1-2 City of Mabton

September 2011 Wastewater Facility Plan

is Mark Adelmund and the City Clerk-Treasurer is Ret Stewart. The City’s current

mailing address and main telephone number are:

City of Mabton

305 Main Street

P.O. Box 655

Mabton WA 98935

(509) 894-4813

The City of Mabton has owned and operated the sewage collection and treatment

facilities in its service area for several decades and possesses the necessary legal,

financial, institutional, and managerial resources to insure the construction, operation, and

maintenance of the proposed treatment works.

HISTORY AND DEVELOPMENT OF THE SEWER SYSTEM

The City of Mabton sewer collection system conveys sewage flows by gravity to a 10-inch

diameter interceptor main that flows to the WWTF. The City has one pump station located

at 202 High School Road.

The original wastewater treatment facilities were constructed in 1954. The system was

replaced by an oxidation ditch system in 1976. A major upgrade was completed in 1999

that included the following improvements:

• Headworks improvements, including a new comminutor, a manually-cleaned rock

trap, an in-channel fine screen system, a new ultrasonic flow meter at Parshall flume,

and a new composite sampler;

• Conversion of an existing tank to new anoxic conditioning tank;

• New 30 hp brush rotor aerators in the existing oxidation ditch;

• One new secondary clarifier;

• New Return Activated Sludge (RAS) and Waste Activated Sludge (WAS) pumps

stations for both secondary clarifiers;

• Ultraviolet (UV) light disinfection system;

• Submersible pump station (for effluent pumping at high Yakima River water levels);

• New aerated WAS storage tank with blower;

• New sludge drying beds with positive displacement pump for feed;

• Improvements and updates to onsite laboratory;

• Installation of Supervisory Control and Data Acquisition (SCADA) computer center;

• Upgrade of electrical system.

REVIEW OF EXISTING REPORTS

Existing documents and reports that were reviewed in preparing this Plan include:


City of Mabton 1-3

Wastewater Facility Plan September 2011

City of Mabton, Engineering Report for the Wastewater Treatment System, Esvelt

Environmental Engineering and Spink Engineering, 1993.

City of Mabton, Wastewater Treatment Plant Operation and Maintenance

Manual, Esvelt Environmental Engineering and Spink Engineering, 2000.

City of Mabton, 2009 Comprehensive Plan Update, Yakima Valley Conference of

Governments.

In addition to the above documents, City of Mabton staff was consulted to help develop

the planning numbers and assumptions used in this Plan. Gray & Osborne and City staff

held several meetings and conducted field inspections throughout the City to evaluate the

condition of the wastewater system.

SCOPE

This document is organized into the following chapters:

Chapter 1 – Introduction. This chapter contains a background of the project, purpose, and

scope of the report.

Chapter 2 – Planning Considerations. This chapter discusses general planning data

required to complete later chapters of the plan.

Chapter 3 – Regulatory Requirements. This chapter discusses the City’s NPDES permit,

Biosolids Management (WAC 173-308) and its effect on the WWTF, and the required

environmental permitting.

Chapter 4 – Wastewater Flows and Loadings. This chapter develops flows and loadings

that will be used in subsequent chapters to evaluate the capacity of the WWTF and to

plan improvements to the existing WWTF.

Chapter 5 – Existing Facilities. This chapter describes and provides a detailed capacity

analysis of the existing WWTF.

Chapter 6 – Wastewater Treatment Facility Improvements. This chapter evaluates

wastewater treatment alternatives and recommends capital improvements at the WWTF.

Chapter 7 – Reuse of Treatment Plant Effluent. This chapter evaluates the opportunities

available for the City of Mabton for beneficial reuse of treated wastewater.

Chapter 8 – Capital Improvement Financing. This chapter presents a plan for the City to

finance the capital improvements and operation and maintenance costs associated with

the wastewater treatment facility upgrades.

CHAPTER 2

PLANNING CONSIDERATIONS

City of Mabton 2-1 Wastewater Facility Plan September 2011

CHAPTER 2

PLANNING CONSIDERATIONS INTRODUCTION The configuration of a wastewater collection and treatment system is influenced by development trends and timing, regulatory requirements, growth considerations, and topography. This chapter provides projections of the population growth within the sewer service area for the 20-year planning period. PLANNING PERIOD The Plan presents a 20-year plan for providing adequate wastewater treatment for the City of Mabton. Therefore, the design year for the recommended capital improvements is 2031. SERVICE AREA The City of Mabton is subject to the State Growth Management Act, which requires cities to plan their growth, avoiding inefficient land use. Figure 2-1 delineates the Mabton city limits and the urban growth area (UGA). A UGA is an area outside the current city limits that the City has identified as potentially experiencing development pressure over the next 20-years. City utilities and services may be gradually expanded into this area as needed. The city limits encompass an area of approximately 525 acres, while the UGA boundary encompasses an area of approximately 578 acres per the 2009 City of Mabton Comprehensive Plan Update. The current sewer service area, shown in Figure 2-1, is defined as the residential, business, commercial, industrial, and public areas served by the existing sewer collection system inside of the existing city limits. PROJECTED SERVICE AREA The sewer service area is expected to grow within the existing city limits and UGA during the 20-year planning period. LAND USE AND ZONING Figure 2-2 shows zoning for the City and the UGA. SERVICE AREA POPULATION


2-2 City of Mabton September 2011 Wastewater Facility Plan

As shown in Figure 2-3, the population of City has doubled since 1970.

FIGURE 2-3 City of Mabton Historical Population (1)

0

500

1,000

1,500

2,000

2,500

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Po

pu

lati

on

(1) Source: Washington State Office of Financial Management.

Figure 2-4 presents the low, medium and high population projections from the 2009 City of Mabton Comprehensive Plan Update and the actual population growth for 2000 to 2010.



Figure 2-4

City of Mabton Comprehensive Plan Population Projections (1), (2), (3)

1,500

1,700

1,900

2,100

2,300

2,500

2,700

2,900

3,100

3,300

2000 2005 2010 2015 2020 2025 2030 2035

YEAR

POPULATION

Actual Low Medium High

3,031

2,576

2,126

(1) The baseline 2000 population was 1,891. (2) Data from the 2009 Comprehensive Plan Update for the years 2000 to 2025. (3) Population projected for 2025 to 2031 at 0.5% for low projection, 1.1 % for medium projection

and 1.5% for high projection. The actual growth between 2000 and 2010 matched the “high” population projection because the actual population in 2010 was 2,165 people. For planning purposes, the 2009 City of Mabton Comprehensive Plan Update states that the medium and high forecasts should be utilized. This Plan will utilize the high population projection, since the historic growth rate matched the high population projection and the 2009 City of Mabton Comprehensive Plan Update requires utilizing the medium or high projection. The high growth rate projection grew at 1.5 percent per year between 2020 and 2025. Therefore, a growth rate of 1.5 percent per year will be utilized to extend the forecast from 2025 to 2031. Table 2-1 projects the City’s population to the year 2031.



TABLE 2-1

City of Mabton Projected Population (1)

Year Projected Population

2010 (1) 2,165 2015 (2) 2,378 2020 (2) 2,575 2025 (2) 2,772 2030 (3) 2,986 2031 (3) 3,031

(1) 2010 actual OFM population of 2,165. (2) Based on the high projection from Table 2-1. (3) Table 2-1 high populations extended at growth rate of 1.5% per year.

City officials do not know of any large businesses with plans to begin operations in the City in the near future. However, as the population increases, new businesses are expected to open, and businesses serving the every day needs of the community are expected to expand to meet these needs. As a result, it is projected that the number of businesses and new residential flow rate for system will continue to grow at the same annual rate as the population. COLLECTION SYSTEM Figure 2-5 presents a map of the sewer system for the City. Table 2-2 presents the sewer system inventory and does not include side sewers. The majority of the collection system is concrete pipes.

TABLE 2-2 Collection System Inventory

Pipe Size Length (Feet) 4-Inch 1,160 8-Inch 35,254 10-Inch 6,440 Total 42,854 No. of Manholes 121

Table 2-3 presents the information about the City’s only lift station located at 202 High School Road that serves the Catholic Family Housing of 33 residential lots.



TABLE 2-3

Lift Station No. 1 Information

Characteristic Data Pump Manufacturer Homa Quantity of Pumps 2

Type Submersible Model Number AMX/1-155/4.3,N

Capacity at TDH 200 gpm Motor 2.7 HP Power 230 Volt Single Phase

Backup Power Diesel Generator

ENVIRONMENTAL FACTORS Various natural features of the service area are discussed below, such as climate, topography, geology, soils, flood plains, and surface and ground water resources. CLIMATE The City’s climate is semi-arid with warm to hot summers and generally mild winters. The mean annual temperature has been 53 F and the mean annual precipitation has been approximately 7 inches. Table 2-4 summarizes the climatological data.

TABLE 2-4 Monthly Climate Summary (1)

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Annual

Average Maximum Temperature

39.3 48.2 57.8 65.9 75.0 82.9 89.5 88.6 79.6 66.6 50.2 39.0 65.2

Average Minimum Temperature

23.5 28.1 33.1 39.1 46.6 54.0 58.9 57.5 48.4 37.6 30.8 23.7 40.1

Average Daily Temperature

31.4 38.1 45.5 52.5 60.8 68.5 74.2 73.0 64.0 52.1 40.5 31.4 52.7

Average Precipitation

1.00 0.64 0.64 0.51 0.50 0.46 0.21 0.39 0.40 0.44 1.01 1.15 7.36

(1) City of Wapato, Data from Natural Resource Conservation Service Climatological Data Summaries.



Physiographic The City of Mabton and its UGA are located in Yakima County, approximately 40 miles southeast of the City of Yakima. The land in and around the City is located near the floodplain of the Yakima River, at an approximate altitude of 718 feet above sea level. The land consists of an essentially flat area of loess over lacustrine or glaciolacustrine deposits. Accompanying drainage flows to the east and northwest in the direction of the Yakima River. The Yakima River flows eastward to its mouth on the Columbia River, approximately 52 miles downstream at Richland. The contours for the City are shown on Figure 2-6. The lands surrounding the City of Mabton and its associated UGA are primarily irrigated agricultural lands. Geology The geologic setting of the Yakima Valley is mostly due to volcanic activity of the tertiary period that occurred in the Cascade Mountains and the Columbia Basin. During the Miocene epoch (12-26 million years ago), basalts originating from large fissures in the earth’s crust in southeastern Washington, flowed westward covering the Columbia Basin and eventually lapping the eastern slope of the Cascade Mountains. Volcanic activity in the Cascade Mountains caused the overlaying of these basalts with the light colored, pumiceous sandstone and conglomerates that make up the Ellensburg Formation. After deposition of the Ellensburg Formation, compressional forces pushed the Yakima basalts and overlying sediments into a series of parallel east-west ridges now referred to Ahtanum, Manastash, Toppenish, Umptanum and Yakima Ridges, Cleman and Saddle Mountains, and the Rattlesnake and Horse Heaven Hills. These ridges were slow to form, enabling the Yakima River to cut gaps as the basalt uplifted. These water gaps are now known as the Selah Gap, through Yakima Ridge to the north, and the Union Gap through Ahtanum Ridge to the south. The Quaternary Period, primarily the Pleistocene Epoch, saw continued volcanic activity in the Cascades, as well as extensive glacial erosion. Glaciers flowed down the Yakima, Naches and Tieton River Valleys, filling both the Upper and Lower Yakima Valleys with glacial sedimentary deposits. This glacial action has contributed largely to the Valley’s existing drainage pattern. However, not all drainage changes in the area were due to glaciations. Both the Columbia and the Yakima Rivers have left an impressive record of their wanderings over the area. During the tertiary period, the Columbia River skirted across the basin area strewing sand, pebbles, and volcanic debris. It is believed that Satus Pass was once the outlet of the Columbia River until subsequent uplifting of the land forced the river east to



its present location. The Yakima River, however, was able to maintain its course, eventually cutting through Selah and Union Gap. Today, the surface geology of the Mabton area consists mainly of unconfined young valley fill including unconsolidated alluvium and the upper part of the Ellensburg Formation of the Miocene age. The young valley fill is made up of silt, sand, gravel, and reaches a maximum thickness of about 500 feet near Wapato, although the thicknesses range typically from 50 to 250 feet. Seismic Hazard All of Washington State is subject to some degree of risk from seismic events. The U.S. Geological Survey (USGS) produces shaking hazard maps, which depict the level of earthquake shaking that have a 10% chance of being exceeded in a 50 year period. The numbers are expressed in as a percentage of g, or the acceleration of a falling object due to gravity, and range from 0 %g (lowered hazard) to 32 %g (highest hazard). The City of Mabton’s %g is approximately 8. Western Washington ranges from 25 to 30 %g, while eastern Washington ranges from 6 to 9 %g. Volcanic Hazard The sources of volcanic hazards within the Mabton area are composite volcanoes of the Cascade Range such as Mt. St. Helens and Mt. Rainier. Potential hazards from an eruption of a composite volcano include mudflows, floods, and tephra (airborne volcanic ash or rock debris). Of these, only tephra from a Mt. St. Helens eruption has an identified potential to affect the area. Of the five principal volcanoes in Washington State, only Mt. St. Helens has experienced major tephra eruptions in the past 13,000 years. Mt. St. Helens has had at least eight large-scale eruptions during that time. During the May 18, 1980 major eruption of Mt. St. Helens, one to five millimeters of tephra was deposited in the area. Tephra ejected during another major volcanic eruption of Mt. St. Helens could fall on the Mabton area, depending on the wind direction at the time of the eruption. It is likely that the size of the tephra (volcanic ash) would be very fine-grained and cooled because of the distance to Mt. St. Helens. The ash deposit could be up to five centimeters thick and would pose a low potential hazard to human life and health. Injury to humans occurs when ash-contaminated air is inhaled. Property damage occurs from the abrasiveness of ash and resulting impacts on machinery. An ash fall in Mabton could result in a temporary shutdown of operations, but is not likely to significantly damage the facilities. Mt. Adams is dormant, not extinct, and it is still potentially active. Future eruptions from Mt. Adams will probably follow patterns set by previous events and will thus be flank lava flows of andesite or basalt. Since the interior of the main cone is little more than a pile of fragmented lava and hydrothermally-altered rock, there is a potential for very



large landslides and other debris flows, but with little chance of affecting the City of Mabton. Soils Most of the City is dominated by Warden Silt loam, with slopes ranging from 0 to 2 percent. It is well drained with very slow to rapid runoff and moderate permeability. Warden soil forms in loess over lacustrine or glaciolacustrine deposits. Warden silt loan is well suited to home development and septic tanks. The primary crops grown in this soil include corn, grain, grapes, hops, mint, peas, and tree fruit. The soil is also well suited to growing legumes and grasses for hay, pasture, and seed. Finley silt loam on 0 to 2 percent slopes dominates much of the UGA and also falls partly into the east side of the City. Finley soils are very deep and well drained, forming in gravelly alluvium with a surface mixture of less. Finley soils hold water in the first eight inches, and the upper seven inches contain less than 1% organic matter. While the soil is generally well suited to home development, seepage may occur in septic tank absorption fields when housing density is moderate to high. As a result, community sewage systems are needed to prevent water supply contamination. The primary crops grown in this soil include corn, grain, grapes, hops, mint, peas, and tree fruit. The soil is also well suited to growing grasses and legumes for hay, pasture, and seed. Wetlands Wetland types listed are based on the Yakima County Critical Area Ordinance. There is one Type 3 wetland indentified on the east side of the City’s UGA. This wetland is in agricultural land north of High School Road and just south of East Euclid Road. There are two lakes to the west of the north end of the UGA (Round Lake and Cockleburn Lake) which have Type 1 and Type 2 wetlands associates with them, and there are also wetlands in this area that are most likely associates with the Yakima River. In addition, there are two Type 2 wetlands to the northeast of the UGA that also are most likely associated with the Yakima River. Neither Type 1 nor Type 2 wetlands fall within the City of Mabton or its UGA. SURFACE WATER The Yakima River is located approximately one mile to the north of the City and flows from west to east in the vicinity of the City. The Yakima River in the vicinity of the Mabton WWTF outfall is deep and slow moving. The Mabton West Lateral of the Sunnyside Irrigation District is located south of the City. The City is located in Water Lower Yakima River Water Resource Inventory Area (WRIA) No. 37. Usable flow data from USGS flow gauging stations in the Yakima River are available both upstream and downstream of the City. However, there are two large irrigation canal diversions downstream of the upper station (Nob Hill), and the Ahtanum Creek



confluence with the Yakima River. These canals have maximum capacities of 2,000 and 1,300 cubic feet per second (cfs), respectively. The return flows from the diversions enter the river before the next flow station (Kiona). Irrigation canals are not always filled to capacity, but the highest flows occur from approximately June 20 to September 20. The Yakima River is managed by the Bureau of Reclamation intensively for irrigation, flooding, and fish passage and rearing by using storage basins. Peak river flow occurs from April to June. The Bureau of Reclamation low flow target in the Yakima River below the diversions for July to September is 300 to 600 cfs depending on the total water supply available. During a drought year with insufficient storage, the Bureau of Reclamation will manage the flow to maintain 300 cfs between Parker and Prosser. Because of the lack of flow data usable for analysis in the reach of the Yakima River in the vicinity of the Mabton Outfall, 300 cfs flow is used as the 7Q10 low flow (the lowest 7-day average river flow with a recurrence of 10 years). The lower Yakima River in the vicinity of the City WWTF outfall has been listed on the Department of Ecology’s 303(d) list of impaired water bodies because of violations of temperature, fecal coliform, dissolved oxygen, and pesticide concentrations. Recently, phosphorus has been measured at levels of concern in the lower Yakima River. In the future, Yakima River Total Maximum Daily Load (TMDL) may be established for pesticides, fecal coliform bacteria, dissolved oxygen, and temperature. It is possible phosphorus will be added to the list of items requiring TMDL. Most of the City is out of the flood plain. A small portion of the south west corner of the City is in the flood plain; see Figure 2-6 for a map of the flood plains adjacent to the City. WATER SUPPLY The City’s potable water supply is provided by ground water wells. The City has two wells that are equipped with pumps and motors and two wells that are not equipped. The wells are 425 to 1180 feet deep and have capacities of 200 to 500 gpm. The wells are chlorinated to provide disinfection throughout the distribution system. The current water system operating permit is classified as Blue by the Department of Health, which means that the water system is adequate for existing uses but is not considered adequate for adding new service connections. However, the City does not currently have a moratorium on service connections. GROUNDWATER The ground water in the vicinity of the City has two discrete aquifer systems; an unconfined and/or semi-confined alluvial aquifer (Ellensburg), and deeper Columbia River basalt aquifers. The basalt aquifers include the Saddle Mountain, Wanapum and the Grande Ronde. The upper groundwater flow follows topography with natural



recharge occurring within the headlands and discharge occurring towards the Yakima River. In this area predominant groundwater flow is from the northwest toward the southeast. According to the Lower Yakima Valley Groundwater Quality Preliminary Assessment and Recommendations Document, the shallow aquifer has high nitrate-nitrogen levels, with at least a third of the wells in the Lower Valley having greater than 5 mg/l nitrate-nitrogen. Nitrate-nitrogen levels of 10 mg/l are considered a potential health risk to the public. ENVIRONMENTAL REVIEW As a part of this Plan, an environmental review has been completed. The review consisted of the preparation and distribution of the State Environmental Protection Act (SEPA) checklist. Supporting documentation has been generated and included as part of the SEPA documentation. In addition to the SEPA, a National Environmental Protection Act (NEPA) report has been generated which addressed all federal requirements. Revisions or additions to the above listed documentation will be made prior to pursuing construction activities outlined in this Wastewater Facility Plan. A copy of the SEPA and NEPA documents are included in Appendix E. The NEPA documentation included the historical and cultural review as outlined in Section 106 of the National Historic Preservation Act. The NEPA documentation includes a biological assessment. TREATMENT FACILITIES SITING The WWTF is located north of the City on Vance Road next to the Mabton Cemetery. Agricultural fields are adjacent to the WWTF to the north and the west while the cemetery is located to the south and the east.

CHAPTER 3

REGULATORY REQUIREMENTS


CHAPTER 3

REGULATORY REQUIREMENTS INTRODUCTION Regulatory requirements are used to develop design criteria as well as devise a long term strategy for discharge of treated liquid effluent and management of residual solids generated by the wastewater treatment process. This chapter indentifies and summarizes the regulations that affect the planning, design, and approval of improvements to the City’s Wastewater Treatment Facilities at the federal, state and local regulatory levels. WATER QUALITY STANDARDS FOR SURFACE WATERS OF THE STATE OF WASHINGTON, CHAPTER 173-201A WAC WAC 173-201A establishes water quality standards for the State of Washington. The standards are based on two objectives: protection of public health and enjoyment, and protection of fish, shellfish, and wildlife. For each surface water body in the state, the standards assign specific uses, such as aquatic life, recreation or water supply uses. Water quality standards have been developed for each use, for parameters such as fecal coliform, dissolved oxygen, temperature, pH, turbidity, and toxic, radioactive, deleterious substances. WATER QUALITY CLASSIFICATION The City’s WWTF discharges into the lower Yakima River (river mile 59.7). The segment of the Yakima River at the City’s outfall is classified in WAC 173-201A-602 as having the following uses:

Aquatic life use: Spawning and rearing; Recreation use: Primary contact recreation; Water supply uses: domestic water supply, agricultural water supply, industrial

water supply, and stock watering; Miscellaneous uses: wildlife habitat, harvesting, commerce and navigation,

boating, aesthetics.

Based on these uses the water quality criteria for the Yakima River at the City’s outfall is shown in Table 3-1.

Gray & Osborne, Inc.


TABLE 3-1 Water Quality Criteria for Yakima River at Mabton Outfall

Parameter Surface Water Criteria Value Fecal Coliforms 100 organisms/100ml maximum geometric mean Dissolved Oxygen >8.0 mg/L Temperature <21°C (7-day average of daily maximum) or 0.3 ºC incremental

increase above background if background is greater than 21°C pH 6.5 to 8.5 standard units, Turbidity <5 NTU over background Toxics No toxics in toxic amounts Samples were collected in the Yakima River upstream of the WWTF outfall July through September of 2005 and 2006 as required by the City’s NPDES permit. Two samples per month were collected by City’s WWTF staff and analyzed by the City of Sunnyside WWTF lab. The results are listed in Table 3-2.

TABLE 3-2 Results of 2005/2006 Receiving Water Sampling and Analysis (1)

Parameter Average Maximum Temperature (°C) 21.9 26.5 Fecal Coliform (colonies/100 ml) 102 297 Dissolved Oxygen (mg/L) 8.71 7.04 (min) pH (standard units) 8.03 8.51 Ammonia (mg/L) 0.33 0.82 (1) From the City of Mabton NPDES Permit Fact Sheet. According to Table 3-2, during the sampling period, both average and maximum temperatures exceeded the Yakima River water quality criterion. Also dissolved oxygen was measured below the water quality criterion during July and August 2005, a low flow period. MIXING ZONES WAC 173-201A-100 has provisions for mixing zones for a permitted discharge. Deviations from water quality standards for the surface water are allowed within the mixing zone. Mixing zones are allowed under the following conditions:

1. All known, available, and reasonable treatment (AKART) is applied prior to discharge to the mixing zone.

2. Water quality is not violated outside the mixing zone boundary.



3. When potential does not exist for damage to sensitive ecosystem or aquatic habitat, adverse public health effects, or interference with characteristic uses of the water.

4. Chronic toxicity criteria are met within a mixing zone that does not exceed 25% of the river width, use more than 25% of the river flow, and does not extend more than 100 ft upstream or 300 ft downstream (plus the depth of water over the discharge port).

5. Acute toxicity criteria are met within a mixing zone that does not exceed 2.5% of the river flow, does not occupy more than 25% of the width of the river, and does not extend beyond 10% of the distance towards the upstream and downstream boundaries of an authorized mixing zone.

The current dilution factors for the City outfall zone are listed in Table 3-3, at the currently permitted design flows as reported in the City of Mabton National Pollution Discharge Elimination System (NPDES) fact sheet. Department of Ecology utilized two methods to determine the dilution factors at the outfall; volume fraction based on the volume of wastewater discharged to river flow and RIVERPLUME5 Model a water quality outfall model.

TABLE 3-3 Outfall Dilution Factors at Currently Permitted Design Flows (1)

Dilution Factor Volume Fraction RIVPLUME5 Model Acute 20.16 26.28 Chronic 282.80 122.13 (1) City of Mabton NPDES permit fact sheet. For these regulatory mixing zones, which are established by the current NPDES permit, the calculated chronic and acute dilution factors are 20.16 and 122.13, respectively at the current design flows. Table 3-4 presents the parameters that were utilized by Ecology to calculate the dilution factors and mixing zones at the WWTF outfall. A mixing zone was not allowed for dissolved oxygen and fecal coliform because the lower Yakima River is listed as impaired on the 303(d) list. The chronic mixing zone is based on the RIVPLUME5 model. The boundaries of the chronic mixing zone are 300 feet long by 31 feet wide downstream and 100 feet upstream.



TABLE 3-4

Modeling Parameters for the Yakima River Receiving Water (1)

Parameter Value Used 7Q10 low Flow 300 cfs Velocity 0.22 ft/sec Depth 1.5 feet to outfall invert; 7.5 feet total Width 180 feet Roughness (Manning’s N) 0.033 Temperature 22.78 °C pH (high) 8.26 SU (90 percentile) Dissolved Oxygen 7.11 mg/L (10 percentile) Total Ammonia- N 0.57 mg/L (90 percentile) Fecal Coliform 211 colonies/100 mL dry weather (90 percentile) (1) City of Mabton NPDES permit fact sheet. Based on the mixing zone analysis in the NPDES permit fact sheet, the following actions are required by the existing permit:

The City will be required to identify and evaluate methods to increase dissolved oxygen in the effluent as part of the plan to maintain adequate capacity (PMAC).

The City will be required to include options to lower the effluent temperature in its PMAC.

A PMAC was required by June 1, 2009 and this Plan will serve as the PMAC.

A water quality model was completed as part of this plan and is included in Appendix C. ANTI-DEGRADATION POLICY The anti-degradation policy (WAC 173-201A-70) aims to maintain the highest possible quality of water in the State, by preventing the deterioration of water bodies that currently have higher quality than the water quality than the standards require. New or expanded actions that may cause a measurable change in water quality must have a Tier II review conducted. For increased wastewater treatment plant discharges, this review will take place as part of the NPDES permit process. Measurable change, for the purpose of the anti-degradation policy, is defined as follows:

Temperature increase greater than 0.3°C Dissolved oxygen concentration decrease greater than 0.2 mg/L Bacteria level increase greater than 2 CFU/100 mL



pH change greater than 0.1 standard units Turbidity increase greater than 0.5 NTU Any detectable change in concentration of toxic or radioactive substances,

which include ammonia and chloride.

A water quality model was completed as part of this plan and is included in Appendix C.

TOTAL MAXIMUM DAILY LOAD (TMDL) Section 303 of the Federal Clean Water Act established the Total Maximum Daily Load (TMDL) program. Under this program, states must establish a list of water bodies that will not achieve water quality standards even with “all known available and reasonable technology (AKART)” in place. Department of Ecology establishes and maintains a list of impaired water body segments, known as the 303(d) list. When receiving water is on the 303(d) list, Ecology will initiate a TMDL study necessary to determine an allotted wasteload for any single discharger. In such situations, Ecology conducts a TMDL analysis to determine the loading capacity of the water body and allocates pollutant loads among point and nonpoint discharges. Based on this loading capacity, “waste load allocations” are established for different pollutant sources in the watershed. The lower Yakima River in the vicinity of the City’s WWTF outfall has been listed on the Department of Ecology’s 303(d) list of impaired water bodies because of violations of temperature, fecal coliform, dissolved oxygen, and pesticide concentrations. Recently, phosphorus has been measured at levels of concern in the lower Yakima. Currently the only TMDL established for the Yakima River is sediment/pesticides. In the future, lower Yakima River TMDL may be established for, fecal coliform bacteria, dissolved oxygen, and temperature. It is also possible phosphorus will be added to the list of items requiring TMDL. DISCHARGE PERMITS The primary means for achieving the water quality standards of WAC 173-201A is the issuance of discharge permits, such as NPDES permits or State Waste Discharge permits, by the Department of Ecology. The City of Mabton’s most current NPDES permit was issued on March 19, 2007 and will expire on April 30, 2012, (refer to Appendix A). Final effluent limits established for the City’s WWTF in its current NPDES permit (Permit No. WA-002064-8) are summarized in Table 3-5.



TABLE 3-5

City of Mabton Final Effluent Limitations (1)

Parameter Average Monthly Average Weekly 5-Day Biochemical Oxygen Demand; BOD5

10 mg/L; 15.8 lb/day = 85% minimum removal

15 mg/L; 23.6 lb/day

Total Suspended Solids; TSS 30 mg/L; 48 lb/day

= 85% minimum removal 45 mg/L; 71/day

Fecal Coliform <100 colonies/100 ml 200 colonies/100 ml pH shall not be outside the range 6.0 to 9.0

Parameter Average Monthly Maximum Daily Dissolved Oxygen 4 mg/L (minimum) 3 mg/L (minimum) Total Ammonia (as NH3-N) 20 mg/L 34.6 mg/L

(1) The average monthly and weekly effluent limitations are based on the arithmetic mean of the samples taken with the exception of fecal coliform, which is based on the geometric mean.

STATE OF WASHINGTON WWTF PLANNING REGULATIONS, WAC 173-240 In accordance with WAC 173-240, engineering reports and General Sewer Plans are required to evaluate treatment alternatives. STATE OF WASHINGTON BIOSOLIDS REGULATIONS, WAC 173-308 WAC 173-308 is the basis for the statewide biosolids management program. Rather than applying for a permit, facilities that are subject to the permit program apply for coverage under the existing statewide general permit. The City of Mabton is covered under the general permit. The City utilizes Natural Selections near Zillah for land application of the biosolids. The current solids treatment process produces biosolids that meet the requirements for Class “B” pathogen reduction by the air drying method. OTHER REGULATORY REQUIREMENTS NATIONAL ENVIRONMENTAL POLICY ACT (NEPA) The National Environmental Policy Act (NEPA) was established in 1969 and requires federal agencies to determine environmental impacts on all projects requiring federal funding or federal permits. If a project is determined to be environmentally insignificant, a Finding of No Significant Impact (FONSI) is issued; otherwise an Environmental Impact Statement (EIS) is required. NEPA is not applicable to projects that do not



include a federal component. It is anticipated that the City will seek federal financing from the State Revolving Fund program therefore a NEPA or equivalent State Environmental Review Process (SERP) must be completed. A NEPA is included as Appendix E. STATE ENVIRONMENTAL POLICY ACT (SEPA) The State Environmental Policy Act (SEPA), as presented in WAC 197-11-960, requires all governmental agencies to ensure that applicable environmental concerns are addressed in the process of project planning and documentation. Projects that have potential environmental impacts must complete a SEPA Checklist to satisfy planning and disclosure requirements. This has been completed with the NEPA and is included in Appendix E. ARCHEOLOGICAL AND CULTURAL RESOURCES SURVEY In November of 2005, the Governor of Washington signed Executive Order 05-05 which requires state agencies to review capital construction projects for potential impacts to cultural resources. This review is to be done in conjunction with the Department of Archeological and Historical Preservation (DAHP) and any affected Tribes. It is anticipated that an archeological and cultural resources review will be completed during the design phase of the WWTF improvements project. During design, the City will contract with a state approved archeologist to perform the survey and to consult with the DAHP and affected tribes. The archeologist’s report will include survey findings as well as any recommended mitigations such as construction monitoring. REGULATORY REQUIREMENTS FOR SHORELINE PERMITTING IN THE STATE OF WASHINGTON The Shoreline Management Program manages shorelines through planning for and supporting all reasonable and appropriate uses of shoreline areas. The Washington State Shoreline Management Act of 1971 (SMA) defines shorelines as including the following:

Lakes of 20 acres or greater, including reservoirs, Streams with a mean annual flow greater than 20 cubic feet per second, Marine waters, Areas within 200 feet landward of surface waters described above, Marshes, bogs, swamps, and river deltas associated with the surface waters

described above. Shoreline permits are required from the local jurisdiction for any sizable development or activity within the shoreline area. Yakima County administers the local shoreline master program. A Shoreline permit will be required if work is conducted on the outfall. JOINT AQUATIC RESOURCES PERMIT APPLICATION (JARPA)



The JARPA application covers several permits that are discussed below. The Washington Department of Fish & Wildlife administers the Hydraulic Project Approval (HPA) process for projects that use, divert, obstruct, or change the nature of flow or bed of any freshwater or marine water of the State of Washington. HPA must include plans and specifications for the proposed action below the high water mark. A 401 Water Quality Certification is required under the CWA for any activity that may result in discharge to surface waters including excavation activities that occur in streams, wetlands, or other waters of the United States. Section 404 of the CWA regulates discharges of fill or dredged materials in wetlands, including any related draining, flooding, and excavation. Pipeline and pump station projects in wetlands will require a Section 404 permit, in addition to any related local permits. In most cases, activities impacting more than 1/3 of an acre will also require a Section 401 Certification. Army Corps of Engineers permit will be required if work is performed in the Yakima River. JARPA permitting at City will only be required if work is conducted on the outfall. REGULATORY REQUIREMENTS FOR STORMWATER PERMITTING IN THE STATE OF WASHINGTON As part of the Federal Clean Water Act, the Department of Ecology administers the State of Washington’s Construction Stormwater General Permit. Stormwater is considered a point source of water pollution and therefore an NPDES permit is required. The State of Washington has developed a General Permit for Construction Stormwater. Stormwater permit coverage is required if the project disturbs more then one acre of land and the possibility of stormwater runoff can enter waters of the state or conveyance systems that convey stormwater to a water of the state. It is anticipated that the construction of the improvements to the WWTF will disturb more than one-acre of land. A Construction Stormwater Permit will be obtained for the project. Due to the lengthy process for permit approval it is anticipated that the City will initially obtain the permit and transfer ownership to the Contractor prior to the start of construction.



YAKIMA COUNTY CODES The WWTF treatment facility is located entirely within Yakima County. The County will require the following permits for the WWTF improvements:

Building Permit (applied for by the City prior to construction, paid for by the Contractor)

Plumbing Permit (obtained/paid for by the Contractor during construction) Electrical Permit (through Labor & Industries) (obtained/paid for by the

Contractor during construction) REGULATORY SUMMARY A summary of the regulatory requirements for improvements to the City WWTF is presented in Table 3-6 .

TABLE 3-6

Summary Regulatory Requirements

Permit/Report Agency Comments NPDES Permit Ecology Expires 04/31/12 Biosolids Permit Ecology Covered under General Permit. NEPA & Biological Assessment Ecology (1) Completed as a part of this Plan.

See Appendix E SEPA City of Mabton Completed as part of the NEPA.

See Appendix E. Cultural /Archeological Survey DAHP Will be completed by the City

during design. Shoreline Permit Yakima County Not required at this time unless

work on outfall is required. HPA (JARPA) Ecology/EPA/

Army Corps of Engineers

Not required at this time unless work on outfall is required.

Construction Stormwater Permit Ecology Applied for by the City during design, transferred to the Contractor prior to the start of construction.

Building Permit Yakima County Applied for by the City during design, obtained and paid for by the Contractor prior to construction activities.

Electrical Permit, Plumbing Permit

Yakima County Obtained by Contractor.

(1) Required for CCWF/SRF Funding.

CHAPTER 4

WASTEWATER FLOWS AND LOADING


CHAPTER 4

WASTEWATER FLOWS AND LOADINGS INTRODUCTION This chapter provides information on existing hydraulic, organic, and solids loadings to the City’s existing WWTF and to present projections of future flows and loadings through the 20-year planning period (2031). Quantifying the existing loading to the WWTF is necessary to determine the level at which the existing wastewater treatment processes are operating, relative to their current capacities, and to project future flows and loadings. Future flows and loadings will be used to size design upgrades to the WWTF that will be required to meet the demands of future growth and regulatory requirements. HISTORICAL WASTEWATER FLOWS The flows at the WWTF are measured with an influent flow meter. The flow meter is a Parshall flume with an ultrasonic level measuring device. Figure 4-1 shows the influent flows at the WWTF from January 2006 to October 2010. The figure shows that the flow meter recorded high flows from October to December 2007 which are greater than twice the average flow. This Plan will assume that the data for months of October to December 2007 are inaccurate and all data for those months will not be utilized in this Plan. A summary of discharge monitoring report data is included in Appendix B.



FIGURE 4-1

Historical WWTF Monthly Average Influent Flows (1) January 2006 –October 2010

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Figure 4-2 presents the daily influent flow to the WWTF except for the months of October to December 2007. Figure 4-2 shows that there is a significant variation in the influent flow. Influent flow meters typically record larger variation in flow due to the inaccuracies in influent meters caused by rags and other objects in the flow. It is possible that some of the high flows are inaccurate: however to be conservative all of the daily flow data will be utilized except for the months of October to December 2007.



FIGURE 4-2

Historical WWTF Average Daily Influent Flows (1)

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Historical wastewater flows are based on data from the WWTF’s discharge monitoring reports (DMRs) for the period January 2006 through October 2010. Annual flow summaries for the past four years are listed in Table 4-1.

TABLE 4-1

Historical WWTF Influent Flows

Year

Population (1)

AAF (2)

(MGD) MMF (3)

(MGD) MDF (4)

(MGD) 2006 2,075 0.165 0.181 0.225

2007 (5) 2,080 0.146 0.169 0.346 2008 2,085 0.157 0.190 0.473 2009 2,100 0.158 0.201 0.238 2010 2,165 0.145 0.184 0.213

Average 2,101 0.154 - - Maximum - - 0.201 0.473 (1) From Figure 2-3. (2) AAF = Average Annual Flow, the average flow for the year. (3) MMF = Maximum Month Flow, the flow for the month with the highest average flow in a

calendar year. (4) MDF = Maximum Day Flow, the flow for the day with the highest flow in a calendar year.



(5) Does not include data for Oct. to Dec. 2007 due to flow meter problems. Table 4-2 presents the per capita flow for the WWTF. The maximum values for per capita flow will be utilized for future projections. Ecology recommends a design value of 100 gallon per capita day (gpcd) on a maximum monthly basis when actual data is not available. The City’s MMF of 96 gpcd is within the expected range of monthly flows.

TABLE 4-2 Historical WWTF Influent Flows per Capita

Year Population (1) AAF (gpcd) MMF (gpcd) MDF (gpcd)2006 2,075 80 87 109

2007 (2) 2,080 70 81 166 2008 2,085 75 91 227 2009 2,100 75 96 113 2010 2,165 67 85 98

Maximum -- 80 96 227 (1) From Figure 2-3. (2) Does not include data for Nov. to Dec. 2007 due to flow meter problems.

PEAK HOUR FLOW The City of Mabton does not record the peak hour flow. The Department of Ecology Criteria for Sewage Works Design recommends a peaking factor 3.6 for AAF to PHF based on a population of 2,100. This peaking factor has been utilized to project PHF. DEFINITION OF INFILTRATION Infiltration is defined as ground water entering a sewer system by means of defective pipes and side sewers, pipe joints and manhole walls. The infiltration rate is relatively constant day to day, although it may vary seasonally if the local ground water elevation fluctuates. Infiltration can be a constant problem, increasing daily operations costs for the collection and conveyance systems. DEFINITION OF INFLOW Inflow is defined as surface water or runoff that enters the collection system through constructed openings such as manhole covers, cross-connections with storm sewers and combined sewers or direct connections such as yard, basement, or roof drains. Inflow is directly related to rainfall or flooding events and results in an immediate increase in sewage flows following the event. Inflow is an intermittent problem, causing an increase in sewage flows following the triggering event.



I/I FLOW CRITERIA The United States Environmental Protection Agency (EPA) has determined specific quantitative guidelines for excessive I/I, as follows:

1. To determine if excessive infiltration is occurring, a threshold value of 120 gallons per capita per day (gpcd) is used. This threshold infiltration value is based on an average daily flow over a seven to fourteen day non-rainfall period during seasonal high groundwater conditions.

For the City of Mabton, the per capita flow during the maximum summer month when rainfall was low and groundwater is highest is 96 gpcd. According to EPA definitions, the City does not have excessive infiltration.

2. To determine if excessive inflow is present in a collection system, the USEPA

uses a threshold value of 275 gpcd. If the average daily flow (excluding major commercial and industrial flows greater than 50,000 gpd each) during periods of significant rainfall exceeds 275 gpcd, the amount of inflow is considered excessive.

During the period 2005-2009, the maximum daily flow was 0.473 MGD, or 227 gpcd. According to EPA definitions, the City does not have excessive inflow.

HISTORICAL LOADINGS The City’s DMRs contain data for WWTF influent and effluent BOD5 and TSS. Figure 4-3 shows the loadings for the past four years. Figure 4-3 does not show any seasonal pattern for the loadings. The City does not have any significant industrial contributors to the WWTF. As shown in Figure 4-3, June and July 2010 BOD5 loadings are much higher than any other months. The per capita BOD5 for those two months are 0.28 and 0.33 lbs per capita day. The next highest per capita loading is 0.23 lbs per capita and this compares to Ecology’s design recommendation of 0.20 lbs per capita. Therefore the BOD5 data from June and July 2010 will not be considered in the evaluation of the influent loadings because this data is unusually high and the City has no industry that could have caused the high BOD spikes. Annual summaries of loadings over the past four years are listed in Table 4-3. Per capita loadings are listed in Table 4-4.



FIGURE 4-3

Historical WWTF Monthly Average Influent Loadings

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TABLE 4-3 Historical WWTF Influent Loadings

Date Avg. Ann.

BOD5 (lb/d)Max Mo.

BOD5 (lb/d)Avg. Ann. TSS (lb/d)

Max Mo. TSS (lb/d)

2006 334 388 314 424 2007 (1) 376 427 318 400

2008 335 417 293 404 2009 395 476 364 505

2010 (2) 399 503 (2) 317 378 Average 368 --- 321 ---

Maximum --- 503 --- 505 (1) Does not include data for Oct. to Dec. 2007 due to flow meter problems. (2) Does not include BOD5 for June and July due to unusually high readings.



TABLE 4-4

Historical WWTF Influent Loadings per Capita

Date Population (1) Avg. Ann.

BOD5 (ppcd)Max Mo.

BOD5 (ppcd)Avg. Ann.

TSS (ppcd) Max Mo.

TSS (ppcd) 2006 2,075 0.16 0.19 0.15 0.20 2007 2,080 0.18 0.21 0.15 0.19 2008 2,085 0.16 0.20 0.14 0.19 2009 2,100 0.19 0.23 0.17 0.24 2010 2,165 0.18 0.23 0.15 0.17

Average --- 0.17 --- 0.15 --- Maximum --- --- 0.23 --- 0.24

(1) From Figure 2-3. Ecology recommends a design value of 0.20 pounds per capita per day (ppcd) on a maximum monthly basis when actual data is not available. The City’s maximum loading of 0.23 ppcd for BOD5 and 0.24 ppcd for TSS is slightly higher than the Ecology recommendation. To be conservative, loadings of 0.23 ppcd for BOD5 and 0.24 ppcd for TSS will be utilized to project future loading. NITROGEN LOADING Total nitrogen is comprised of organic nitrogen, ammonia, nitrite, and nitrate. Organic nitrogen is determined by the Kjeldahl test method. Total Kjeldahl nitrogen (TKN) is the total of the organic and ammonia nitrogen. TKN loadings are used to design and size the nitrogen removal processes at the facility. Currently there are no measurements of TKN at the influent of the WWTF. Typical domestic wastewaters have a 5:1 BOD5:TKN ratio. A more conservative ratio of 4.5:1 has been used to project the design nitrogen load for the WWTF, based on our experience with small cities in Eastern Washington. SUMMARY OF PROJECTED WASTEWATER FLOWS AND LOADINGS A summary of the projected design wastewater flows and loadings for the WWTF is presented in Table 4-5. As shown in Table 4-5, the projected design wastewater flows and loadings exceed the existing NPDES permit capacity. Therefore expansion of the WWTF will be required.



TABLE 4-5 2031 Projected Design Wastewater Flows and Loadings

and NPDES Permitted Capacity

Flow or Loading NPDES Permitted

Capacity Projected Design

Value Sewer Service Population --- 3,031 (1) Average Annual Flow (MGD) 0.166 0.24 (2) Maximum Month Flow (MGD) 0.189 0.29 (3) Maximum Day Flow (MGD) --- 0.69 (4) Peak Hour Flow (MGD) --- 0.87 (5) Annual Average BOD5 Loading (lb/d) --- 515 (6) Maximum Month BOD5 Loading (lb/d) 478 697 (7) Annual Average TSS Loading (lb/d) --- 455 (8) Maximum Month TSS Loading (lb/d) 453 727 (9) Maximum Month TKN Loading (lb/d) --- 155 (10)

(1) From Table 2-1. (2) Sewer Service Population x 80 gpcd from Table 4-2. (3) Sewer Service Population x 96 gpcd from Table 4-2. (4) Sewer Service Population x 227 gpcd from Table 4-2. (5) AAF x peaking factor of 3.6. (6) Sewer Service Population x 0.17 ppcd from Table 4-4. (7) Sewer Service Population x 0.23 ppcd from Table 4-4. (8) Sewer Service Population x 0.15 ppcd from Table 4-4. (9) Sewer Service Population x 0.24 ppcd from Table 4-4. (10) Maximum Month BOD5 Loading / 4.5.

CHAPTER 5

WWTF EVALUATION


CHAPTER 5

WWTF EVALUATION GENERAL This chapter evaluates the existing WWTF with respect to capacity, reliability, and redundancy, and to identify improvements to the WWTF to accommodate the design criteria as outlined in Chapter 4. The City of Mabton owns and operates the wastewater treatment facilities that serve the sewer service area. The treatment facilities include an automatic screen, anoxic selector, oxidation ditch, secondary clarifier, return/waste activated sludge pumping station ultraviolet (UV) disinfection, high water level pumping station and an outfall to the Yakima River. The solids treatment facilities include a waste sludge pump, aerobic digestion and sludge drying beds. PROJECTED WASTEWATER FLOWS AND LOADINGS The process units evaluated in this chapter are based on the projected flows and loadings developed in Chapter 4. Table 5-1 is a summary of the design flows and loadings for the year 2031.

TABLE 5-1 2031 Projected Design Wastewater Flows and Loadings

Flow or Loading Projected Design Value (1) Sewer Service Population 3,031 Average Annual Flow (MGD) 0.24 Maximum Month Flow (MGD) 0.29 Maximum Day Flow (MGD) 0.69 Peak Hour Flow (MGD) 0.87 Annual Average BOD5 Loading (lb/d) 515 Maximum Month BOD5 Loading (lb/d) 697 Annual Average TSS Loading (lb/d) 455 Maximum Month TSS Loading (lb/d) 727 Maximum Month TKN Loading (lb/d) 155

(1) From Table 4-5.



FUTURE PERMIT LIMITS The City’s current NPDES Permit was issued in 2007 and will expire in 2012. Complete analysis of the outfall and the model results are presented in Appendix C. Table 5-2 presents the projected effluent permit limits for the City’s WWTF based on outfall modeling.

TABLE 5-2

City of Mabton WWTF Future Projected NPDES Permit Effluent Limits


BOD5 N/A 10 mg/L, 24.2 lb/day,

85% removal of influent BOD

15 mg/L, 40.7 lb/day

TSS N/A 30 mg/L, 72.6 lb/day,

85% removal of influent TSS

45 mg/L, 122 lb/day


pH Daily minimum is equal to or greater than 6 and the daily

maximum is less than or equal to 9


Total Ammonia (as NH3-N)

4.5 mg/L 2.9 mg/L N/A

The future projected permit limits will lower the total ammonia limit by 85 percent over the existing permit limits. This will require the oxidation ditch to include nitrification to ensure that the ammonia is converted to nitrates. The BOD5 monthly limit was lowered during the last permit cycle from 30 mg/L to 10 mg/L. Even though the WWTF has been meeting the 10 mg/L limit, the existing WWTF was never designed to meet this limit. This low limit will require that all alternatives provide methods to create good settling solids and the clarifiers shall meet current design standards. Also the clarifiers will be required to meet the current design requirements for clarifiers to prevent BOD5 from being carried over the weir with the solids that exit the clarifiers. The City realizes the importance of planning for future limits. Potential future limits include nitrogen, phosphorus, and metals. In October 2008, Ecology received funding from the EPA to conduct an evaluation of nutrient removal technologies at municipal WWTFs across the State of Washington. This nutrient removal study is being performed to identify the technical and economic issues related to the removal of nitrogen and



phosphorus from WWTF effluent. Ecology permit managers are encouraging all cities to consider nutrient removal as part of the planning process. The lower Yakima River in the vicinity of the City’s WWTF outfall has been listed on the Department of Ecology’s 303(d) list of impaired water bodies because of violations of temperature, fecal coliform, dissolved oxygen, and pesticide concentrations. Recently, phosphorus has been measured at levels of concern in the lower Yakima River. In the future, a total daily maximum load (TMDL) for the lower Yakima River may be established for fecal coliform bacteria, dissolved oxygen, and temperature. It is possible phosphorus will be added to the list of items requiring a TMDL. Currently the only TMDL established for the lower Yakima River is for DDT. The DDT in the river is attached to soil that enters the river from agricultural fields. Ecology utilizes turbidity to determine how much soil is in the water. Therefore, Ecology has set limits for turbidity as a proxy for DDT. This TMDL has been successful in lowering the DDT in the river. The City’s WWTF is not affected by the DDT TMDL. According to the existing NPDES permit, this Plan must evaluate how the WWTF will achieve the following:

Increase dissolved oxygen in the effluent. Lower the effluent temperature.

This Plan will evaluate methods to increase effluent dissolved oxygen, lower effluent temperature, and nitrogen removal in preparation of future permit limits. The Plan will not evaluate methods to remove phosphorus because phosphorus has not been added to the items requiring a TMDL. Therefore any requirement to remove phosphorus is not anticipated for a minimum of 10 to 15 years based on conversations with Ecology. EXISTING OPERATION The wastewater enters the WWTF at a diversion box, which can be utilized to bypass the headworks. Wastewater treatment begins when raw wastewater enters a rock trap, which is designed to allow rocks to settle from the wastewater and accumulate on the floor of the trap. Next, the wastewater flows through the bar screen in a channel. The wastewater continues to the fine screen, which screens out rags and other inert objects. A Parshall flume downstream of the screen measures the influent flow. At the Parshall flume, a flow paced sampler collects composite wastewater samples for laboratory analysis. The screened wastewater is mixed with return activated sludge (RAS) in the anoxic sewage conditioning tank before flowing to the oxidation ditch. The oxidation ditch biologically converts the organic material in the wastewater into biological cells and



metabolic end products. Two cage rotors provide oxygen and mixing of the oxidation ditch. Flows from the oxidation ditch are conveyed to the secondary clarifiers. The secondary clarifiers provide a quiescent environment where settleable secondary solids are removed from the treated wastewater. The clarifiers can be operated individually, in parallel, or in series operation. Secondary effluent flows to the UV system for disinfection. The UV system effluent flows to an effluent pump station. The effluent pump station pumps the water to the river when the river is flooding, otherwise during normal operation the wastewater flows by gravity through the effluent pipeline to the submerged outfall in the Yakima River. A flow-paced automated sampler collects composite wastewater samples for laboratory analysis. The facility’s sludge treatment process begins with the pumping of the waste activated sludge from the clarifiers to the aerobic digestion. The solids are then pumped to the sludge drying beds where the solids are air dried to Class B quality prior to final disposal of the biosolids by land application off-site. A schematic flow diagram, hydraulic profile and existing site layout are provided as Figures 5-1, 5-2 and 5-3. SEWER COLLECTION SYSTEM LIFT STATION NO. 1 Lift Station No. 1 serves the Catholic Family Housing and its location is shown in Figure 2-5. Table 2-4 provides the design information for the lift station. Wastewater from 33 residential lots flow to Lift Station No. 1 and not all of the lots have residences. The 200 gpm lift station has a capacity of approximately 225 single family residences (200 gpm / (80 gpcd AAF x 4 person/house x 4 peaking factor) / 1440 min/day). The lift station has capacity for 225 residences which is sufficient for the 20-year planning period. The lift station is new (< 5 years old) and is equipped with a diesel generator. The lift station does not require any improvements. INTERCEPTOR SEWER The existing 10-inch diameter interceptor sewer line along Vance Street conveys sewage to the WWTF from the City. The 10-inch sewer has a slope of 0.006 ft, resulting in a capacity of 1.8 MGD. This capacity is greater than the projected design peak hour flow of 0.87 MGD; therefore the sewer interceptor has sufficient capacity for the 20-year planning period.



COLLECTION SYSTEM The sewer interceptor and most of the sewers in the City are concrete pipe. The majority of the sewers is at least 65-years old and were constructed 1954. There are no recent videos of the sewers; therefore, the condition of the sewers is unknown. There are no reported sewer failures, but some of the sewers could be reaching the end of their useful life. Department of Ecology has recommended an infiltration and inflow study of the sewers to determine the condition of the existing collection system. An infiltration and inflow study would include video recording of the collection system to determine the structural integrity of the pipes. It is recommended that an I/I study be performed. Chapter 6 further describes this study. WASTEWATER TREATMENT FACILITY (WWTF) HEADWORKS Process Description Raw wastewater enters the rock trap where large rocks that could damage the fine screen are removed by gravity settling. The rock trap is functionally obsolete because it does not remove grit. From the rock trap, the wastewater flows to the comminutor structure. The comminutor is no longer in service because its function was replace by the fine screen, therefore the wastewater flows though a bar screen bypass channel to bypass the comminutor. The wastewater then flows to the mechanical fine screen for the removal of large debris, such as rags and plastics. Downstream of the fine screen, the wastewater enters a Parshall flume equipped with an ultrasonic level sensor used to determine flow. A composite sampler is programmed to take samples of the influent wastewater at the Parshall flume based on the current flow rate. Table 5-3 presents the design criteria for the headworks.

TABLE 5-3 Headworks Design Criteria

Headworks Rock Trap Type ChannelRock Trap Channel Quantity 2Bypass Bar Screen Type Bar 1-inchFine Screen Model Schloss Mark XV-aFine Screen Channel Width 16 inchFine Screen Openings 1/8 inchFine Screen Capacity 0.5 MGDFlow Meter 3-inch Parshall Flume, Ultrasonic



Structural The headworks concrete structures appear to be in good condition. However, there are no drains in the channels; therefore it is difficult to empty them for cleaning. Mechanical The headworks does not have grit removal equipment, grit removal is necessary to prevent grit from settling in tanks and to prevent wear and tear on equipment. The fine screen utilizes an auger to remove objects over 1/8-inch in diameter from the wastewater and convey the screenings out of the channel. The angle of the fine screen is steep and the screenings tend to fall back out of the auger and into the channel, instead of being conveyed up the screen. The fine screen wash water is not equipped with an automatic solenoid to provide automatic washing when the screen screw operates; therefore the wash water runs continuously. The wash water line also needs freeze protection. The effluent at the outlet of the Parshall flume box backs up into the flume due to the high elevation of the Parshall flume outlet piping. This backup of effluent can affect the accuracy of the Parshall flume. The influent sampler is adequate and does not have mechanical problems. Capacity The fine screen has a capacity of 0.5 MGD, which is less than the projected design peak flow of 0.87 MGD. Therefore, the fine screen is not adequate for the 20-year planning period. The existing 3-inch Parshall flume has a maximum capacity of 0.74 MGD which is less than the projected design peak flow 0.87 MGD. The Parshall flume does not have sufficient capacity for the 20-year planning period. It is recommended that the fine screen and Parshall flume be replaced and that the grit channel be added. SEWAGE CONDITIONING TANK Process Description The effluent from the headworks flows to the sewage conditioning tank, which is intended to act as a biological selector basin, by providing the environmental conditions necessary to promote the growth of floc-forming microorganisms. Floc-forming microorganisms are necessary to achieve efficient liquid/solids separation in the secondary clarifier. The sewage conditioning tank receives effluent flow from the headworks, return activated sludge (RAS) from the clarifiers and supernatant from the aerobic sludge storage tank. The sewage conditioning tank has a vertical turbine mixer to



keep solids in suspension. Table 5-4 presents the design criteria for the sewage conditioning tank.

TABLE 5-4 Sewage Conditioning Tank Design Criteria

Sewage Conditioning Tank

Quantity 1Volume 15,700 galMixer Type Vertical TurbineHorsepower 3 hpDrive Variable Frequency Drive

Structural The sewage conditioning tank is in good condition and should be capable of remaining in service for an additional 20 years. Mechanical To promote good settling microorganisms, biological selectors typically have more than one zone. The sewage conditioning tank has only one zone. The sewage conditioning tank currently has two feet of grit in the bottom of the tank. The mixer is in good condition. Capacity For biological selection, a relatively high F/M (food to microorganism ratio) should be utilized to increase the concentration of readily available (soluble) BOD5. The biological selector should have an overall F/M ratio of 6-8 g BOD/g Mixed Liquor Suspended Solids (MLSS) d for a biological selector with only one zone. The existing and projected F/M ratios are as follows: Existing Maximum Month BOD5: 503 lb/day Projected Maximum Month BOD5: 697 lb/day Existing MLSS: 3,500 mg/L Sewage Conditioning Tank Volume 15,700 gal F/M = BOD5 / MLSS / (Tank Volume/1,000,000 gal) / 8.34

Existing F/M 1.1 (503 lb/day / 3,500 mg/L / (15,700 gal / 1,000,000 gal) / 8.34)

Projected F/M 1.5 (697 lb/day / 3,500 mg/L / (15,000 gal / 1,000,000 gal) / 8.34)

The F/M ratio is significantly less than the recommended typical design values of 6-8 g BOD/g MLSSd due to the large volume of the tank. For the past five years, the WWTF



has produced an average effluent TSS of 9.8 mg/L and the sludge volume index (SVI) has been 150-190 ml/g. SVI valves of less than 150 are typically required for good settling performance in the clarifiers. The biological selector is oversized and functionally obsolete and will not adequately control SVI to produce good settling solids in the treatment facility. It is recommended that new bioselectors be constructed to ensure that the facility creates good settling solids. OXIDATION DITCH Process Description The oxidation ditch is a large elliptical reinforced concrete tank which serves as the aeration basin for the activated sludge process. The liquid contents of the oxidation ditch are referred to as the “mixed liquor”. The mixed liquor is aerated, completely mixed, and propelled around the elliptical tank by two brush rotor aerators. The organic waste provides the food source for the bacteria in the mixed liquor. Aeration provides the oxygen required by the bacteria to assimilate and break down the organic waste. The bacteria use the biodegradable organic waste material as a source of energy (through oxidation) and as a source of carbon for cell synthesis (to produce new bacterial cells). The bacterial population is continually dying and being replaced by synthesis. Ideally, the biological activities in the treatment process will be balanced so as to maintain an adequate biological population to process the available food supply. The bacteria cells are removed by gravity sedimentation in the secondary clarifier and returned to the oxidation ditch through the sewage conditioning tank described above. A small fraction of the solids are occasionally wasted to the aerobic sludge storage tank to maintain the desired solids concentration in the activated sludge system. Design criteria for the oxidation ditch are provided in Table 5-5.

TABLE 5-5 Oxidation Ditch Design Criteria

Oxidation Ditch

Volume 198,000 gal Channel Width 19 ft Overall Length 145 ft Side Water Depth 6 ftBrush Rotos Quantity 2 Rotor Length 16 ft Rotor Diameter 42 in Motor 30 hp, VFD Capacity @ 9-inch immersion (each) 47 lb O2/hr @ 72 rpm



Structural The concrete in the oxidation ditch tank is in good condition and should be capable remaining in service for an additional 20 years. Mechanical The oxidation ditch has less than six inches of freeboard at maximum oxidation ditch water level. At this operating level, the rotors have a submergence of approximately 9 inches. The control system that adjusts the speed of the rotors based on oxygen levels in the ditch is inoperable. The operator controls the rotor speed manually. The rotors are missing some fins. The rotors do not have covers and therefore can create excessive aerosol mist. The current ditch is shallow (6-feet), which limits oxygen transfer. Capacity Nitrification of ammonia to nitrates is required at Mabton because of the low ammonia effluent limits. Oxidation ditch capacity requirements are dependent on three major design criteria. These criteria are solids retention time (SRT), net heterotrophic and autotrophic yields, and design mixed liquor suspended solids (MLSS) concentration. SRT is the criteria of greatest importance for nitrification. The net specific growth rate of the nitrifying biomass is an order of magnitude lower than that of carbon oxidizing bacteria and is therefore used as the basis for determining the SRT of the oxidation ditch system. Also, the SRT used to calculate the required value for nitrification must be the aerobic SRT since nitrification only occurs under aerobic conditions. SRT Calculation The first step is to calculate the maximum specific nitrifier growth rate (n,m), decay rate (kdn), and ammonia half saturation coefficient (KN) at the winter design temperature of 8oC (coldest 7-day average ditch temperature 2006-2010) using the following equations.

n,m,8 = (n,m) x (t-20) = (0.9/d) x (1.0728-20) = 0.391/d kdn,8 = (kdn) x (t-20) = (0.17 mg/L) x (1.0298-20) = 0.121 mg/L KN,8 = (KN) x (t-20) = (0.7 mg/L) x (1.0538-20) = 0.377 mg/L

The numerical values for the various parameters above are typical for domestic wastewater. Assuming typical values for effluent ammonia concentration of 1 mg/L, a dissolved oxygen concentration (DO) of 2.0 mg/L, and an oxygen half saturation coefficient (KO) of 0.5 mg/L, the actual nitrifier growth rate is calculated as follows:



n = (n,m,8)

DOK

DO

NK

N

ON

- kdn,8 = (0.391/d)

0.25.0

0.2

0.1377.0

0.1- 0.121 /d

This yields a net specific nitrifier growth rate of 0.106/d, which is then used to calculate the required SRT using the following equation:

SRT = 1/n = 9.4 days Applying a safety/peaking factor of 1.5 to this value, to account for daily fluctuations in ammonia loading, produces a required oxidation ditch SRT of 14 days. In order to calculate the aerobic mass required for the design SRT, the net sludge production for the treatment system must first be estimated. Assuming a typical cell yield of 0.4 lb VSS/lb biodegradable COD (bCOD), a typical influent wastewater and biomass VSS/TSS ratio of 0.85, and a design temperature of 8oC, the total sludge production can be determined using the following equation:

iTSSiVSS

tdn

xn

td

tdd

tdX XX

SRTk

NOY

SRTk

SRTSSYkf

SRTk

SSYP

85.0185.0185.01 ,,

0,

,

0

Where: PX = mass of waste activated sludge per day, lb/d (to be determined) Y = heterotrophic cell yield = 0.40 lb/lb bCOD (typical for domestic

wastewater) Yn = autotrophic cell yield = 0.12 lb/lb TKN (typical for domestic

wastewater) S = mass of influent bCOD, taken as 1.6 x influent BOD5 = 1,115 lb day

(697 lb/day x 1.6) So = mass of effluent bCOD, taken as 1.6 x effluent BOD5 = 19 lb/day (5

mg/L x 1.6 at 0.290 MGD based on discharge limit of 10 mg/L) fd = fraction of cell mass remaining as cell debris = 0.15 lb/lb (typical for

domestic wastewater) kd,t = endogenous heterotrophic decay coefficient, d-1 (see below) kdn,t = endogenous nitrogenous decay coefficient, d-1 (see above) SRT = solids retention time of the SRT = 15 days (see above) XiVSS = volatile nonbiodegradable solids, taken as 30% of influent TSS = 218

lb/day (30% of 727 lb/day TSS) XiTSS = influent nonvolatile suspended solids, taken as 30% of influent TSS =

218 lb/day (30% of 727 lb/day TSS) t =oxidation ditch temperature = 8oC NOx = amount of influent TKN oxidized to nitrate, taken as 80% of influent

TKN = 124 lb/day or 51 mg/L. The value for kd can be determined as follows.



ddkk t

nd/075.004.1/12.0 20820

max,8, 0 (typical for domestic wastewater)

The sludge production can then be calculated as follows:

218218

85.015121.01

12412.0

85.014(075.01

1419115,1)4.0)(075.0(15.0

85.014075.01

19115,14.0

XP

734XP lb/day

This equation yields a total estimated sludge production of 734 lb/day. At the design SRT of 14 days, this waste sludge production results in a required total aerobic mass of 10,275 lbs. With a known oxidation ditch volume of 198,000 gallons, the required MLSS concentration can be calculated, which is 6,619 mg/L. Wastewater Engineering (Metcalf & Eddy, 2003) recommends a design MLSS of no more than 4,000 mg/L, since higher concentration can cause solids overloading in the secondary clarifiers. With a required MLSS of 6,619 mg/L, the existing ditch does not have the capacity to treat the 20-year projected flow. Chapter 6 will investigate alternatives to increase treatment capacity. Aeration Requirements To biologically oxidize the BOD5 in the wastewater into bacteria and harmless end products, oxygen must be continuously added to the oxidation ditch. The required quantity of oxygen consists of a carbonaceous oxygen demand and a nitrogenous oxygen demand. The carbonaceous oxygen demand is calculated as follows: Carbonaceous O2 Demand = S – So – 1.42(Pxbio) Where: S = mass influent bCOD, 1,115 lb/d (461 mg/L at 0.290 MGD from above) So = mass effluent bCOD, 19 lb/d (8 mg/l at 0.290 MGD from above) Pxbio = 0.85(Px) - XiVSS-XiTSS = 0.85(734) - 218 - 218 = 188 lb/d Therefore, the carbonaceous oxygen demand is 829 lb/d. The nitrogenous oxygen demand is calculated by the amount of nitrogen oxidized to nitrate: Nitrogenous O2 Demand = 4.33(TKN - NH4 - 0.12(Pxbio)) Where: TKN = influent TKN = 155 lb/day NH4 = effluent ammonia, 2.4 lb/d (1 mg/L concentration at 0.290 MGD) Pxbio = 188 lb/d (from above)



Therefore, the nitrogenous oxygen demand is 563 lb/d. The total oxygen demand is the sum of carbonaceous and nitrogenous oxygen demand, or 1,392 lb/d. Applying a safety factor of 1.5 to account for fluctuations in diurnal loads results in a design oxygen demand of 2,089 lb/d, which is the required actual oxygen transfer rate (AOTR). Oxygenation equipment is specified based upon standard oxygen transfer rate (SOTR), the oxygen transfer rate in clean 20oC water with no suspended solids. The SOTR is calculated as follows:

20

20

024.1

T

S

OSTH

C

CCSOTRAOTR

Where: = oxygen transfer correction factor, 0.7 (Metcalf and Eddy states the range

is 0.6 to 1.2 for mechanical aeration equipment. Based on low oxygen levels in the existing ditch, the value should be on the low end of the range of valves).

= salinity surface tension factor, 0.95 CSTH = dissolved oxygen concentration at operating temperature and elevation, = 8.08 mg/L CS20 = dissolved oxygen concentration at 20oC and 1 atm, 9.08 mg/L CO = operating dissolved oxygen concentration, 2 mg/L T = 25oC (max 7-day wastewater temperature observed in recent DMRs) The resulting SOTR is therefore 3,632 lb/d or 151 lb/hr. Typically rotors capacity are derated by 25%, therefore each rotor can supply 47 lbs/hr of oxygen transfer at 9 inch submersion (measured maximum immersion) and 72 rpm. The WWTF must meet Class II reliability which requires each rotor to supply 100 percent of design oxygen transfer rate. The rotors are not adequate for the 20-year planning period. Chapter 6 will investigate alternatives to increase aeration capacity. Alkalinity Requirements The stoichiometric reaction for the oxidation of ammonia nitrogen to nitrate shows that two moles of hydrogen are produced for every mole of ammonia nitrogen oxidized. In a wastewater treatment system, these hydrogen ions are neutralized by the wastewater’s natural alkalinity (buffering capacity), preventing this acidic condition from significantly reducing the pH within the treatment system. However, if the alkalinity present in the influent wastewater is not sufficient to neutralize the hydrogen ions released during nitrification, the pH within the system will begin to drop. This, in turn, can lead to a significant reduction in nitrification efficiency. pH readings outside the range from 7.2 to 8.0 can have an inhibitory effect on the nitrifying organisms. The amount of alkalinity consumed in the biological process is calculated as follows:



Consumption = (Nitrification)(7.14 mg CaCO3)

= (80% of influent TKN of 155 lb/day)(7.14 mg CaCO3) = (124 lb/day)(7.14 mg CaCO3) = 885 lb/day

The total alkalinity consumed is calculated at 885 lb/d or 366 mg/L (885 lb/d / 0.290 MGD/8.345). An alkalinity of 80 mg/L is required in the oxidation ditch to maintain a pH of 7.2. The total required alkalinity is 446 mg/L. Measured alkalinity in the influent is 370 mg/L. Chapter 6 will investigate alternatives to recover alkalinity. SECONDARY CLARIFIERS Process Description Following biological treatment, effluent from the oxidation ditch flows by gravity to the two circular secondary clarifiers. The secondary clarifiers provide a quiescent environment where settlable solids are separated from the flow by gravity sedimentation. Settled sludge is transported by mechanically operated rotating rake arms along the floor of the clarifier to a central hopper. Solids are removed from the hopper for return to the oxidation ditch or wasting by means of the return activated sludge (RAS) pumps. Effluent exits the clarifier by passing over a weir at the edge of the tank. The secondary clarifiers operate in either series or parallel operation. In series operation the clarifiers operate with effluent flowing from Secondary Clarifier No. 1 to Secondary Clarifier No. 2. Normally the clarifiers operate in series. Design criteria for the secondary clarifier are provided in Table 5-6.

TABLE 5-6 Secondary Clarifier Design Criteria

Secondary Clarifiers

Quantity 2Type Circular; Center Feed, Peripheral Withdrawal Clarifier No.1 Clarifier No.2Diameter 28 ft 30 ftSide Water Depth 8 ft 11 ftSurface Area 616 ft2 707 ft2



Structural The secondary clarifier tanks are in good condition and should be capable of continual operation for the 20-year planning period. Mechanical The weirs on both clarifiers are not level. The feed wells on both clarifiers collect excessive quantities of scum. The clarifiers do not have spray bars. The Clarifier No. 1 feed well is too small based on current design standards. The Clarifier No. 1 scum mechanism needs refurbishment because of a broken scum arm. Clarifier No. 1 is very shallow (8-feet). Typical Clarifier depths are 12-14 feet. The effluent BOD5 average monthly limit is 10 mg/L, which is difficult to meet with clarification alone. The WWTF has been able to meet this limit by operating the clarifiers in series. When operated in series, all of the flow first goes to the smaller Secondary Clarifier No. 1. The first Clarifier in series receives the highest loading and the second Clarifier is lightly loaded, thus producing a more clarified effluent. Since Clarifier No. 1 must receive 100 percent of the flow it is overloaded and its shallow nature makes Clarifier No.1 functionally obsolete. Clarifier No. 1 must be replaced with a new larger Clarifier to allow the WWTF to continue to meet 10mg/l BOD average monthly limit. Capacity As noted in the Criteria for Sewer Works Design, in order to meet Ecology’s reliability standards for a reliability class II facility, the secondary clarifier system must be capable of treating 50 percent of the design flow when the largest clarifier is out of service. Since Clarifier No. 1 is functionally obsolete, therefore it is recommended that a new clarifier be constructed that meets current sizing criteria. Wastewater Engineering (Metcalf & Eddy, 2003) recommends a maximum surface loading rate of 400-700 gpd/ft2 at maximum month flow and 1,000-1,600 gpd/ft2 at peak hour flow. The overflow rate for Secondary Clarifier No. 2 is 410 gpd/ft2 at maximum month flow and 1,231 gpd/ft2 at peak hour flow. The hydraulic capacity of Secondary Clarifier No. 2 is adequate for the 20-year planning period. In addition to recommendations for surface loading rates, Wastewater Engineering recommends solids loading rates of 24-36 lb/ft2/d at maximum month flow and 43 lb/ft2/d at peak hour flow. The solids loading rate for Secondary Clarifier No. 2 is 13.7 lb/ft2/d at maximum month flow and 42 lb/ft2/d at peak hour flow. The solids loading capacity of Secondary Clarifier No. 2 is adequate for the 20-year planning period.



RETURN AND WASTE ACTIVATED SLUDGE SYSTEM Process Description Return Activated Sludge (RAS) is withdrawn from the bottom of the clarifier by pipes from a sludge collection box. Each clarifier has a pump station with two pumps. One pump is dedicated to being a RAS operation, and the second pump is dedicated to Waste Activated Sludge (WAS) operation. The piping is arranged such that the WAS pump can be the backup to the RAS pump. Each RAS pump has a dedicated magnetic flow meter to record flow. The WAS line to the aerobic sludge storage tank has a magnetic flow meter to measure WAS flow. The pump stations are also utilized to pump scum to the aerobic digester manually. Design criteria for the RAS/WAS system are provided in Table 5-7.

TABLE 5-7 RAS/WAS Pumping System Design Criteria

RAS System RAS Pump Quantity 2 Type Self Priming Centrifugal Capacity @ TDH 150 gpm @ 30 ft Motor 5 hp Drive Variable Frequency Drive Flow Meter 4” magneticWAS Pump Quantity 2 Type Self Priming Centrifugal Capacity @ TDH 150 gpm @ 30 ft Motor 5 hp Drive Variable Frequency Drive Flow Meter 3” magnetic Mechanical During the winter of 2010 all of the heaters for the RAS pump enclosures failed, and one RAS pump froze resulting in a cracked pump casing. The WAS pumps become air bound when pumping scum especially from Clarifier No. 1. The enclosures for the pumps are small and make maintenance difficult. New larger maintenance enclosures with heaters are recommended for maintenance reasons.



Capacity Criteria for Sewage Works Design states that the typical process design value for the RAS rate is 50 percent of MMF influent flow. With this criterion, 300 gpm RAS pumps (150 gpm each station) will allow for a MMF 0.432 MGD. This is greater than the projected MMF. The RAS pumps are adequate for the planning period. The oxidation ditch analysis above shows a maximum waste activated sludge production of 731 lb/d at 0.29 MGD. Assuming a WAS concentration of 10,000 mg/L, 731 lb/d is equal to a WAS flow rate of approximately 8,754 gpd. A 150 gpm WAS pump has capacity of 216,000 gpd and can pump this sludge volume in 1.0 hours per day of pumping. The WAS pumps have adequate capacity. DISINFECTION Process Description Clarified effluent from the secondary clarifier flows through underground piping to the ultraviolet disinfection system. The ultraviolet light inactivates pathogenic organisms in the effluent prior to discharge to the Yakima River. Design criteria for the UV disinfection system are provided in Table 5-8.

TABLE 5-8 UV Disinfection System Design Criteria

UV Disinfection System Number of Banks 2 Lamps per Bank 16 Number of Modules per Bank 4 Number of Lamps Per Module 4 Design Dose @ 0.5 MGD 33,000 µ Ws/cm2 @ 65% transmittance Structural The concrete channel is in good condition and should be capable of continual operation for the 20-year planning period. Mechanical The current ultraviolet disinfection system installed at the WWTF is no longer being fabricated, and the City has a difficult time getting parts or bulbs for the system. In addition the operator cannot access the programming for the system. Due to the lack of proper ventilation and insulation damage caused by being improperly covered, it is recommended that the UV building be modified to correct these issues.



Capacity Typical disinfection design for a UV system requires a dosage of 30,000 to 40,000 µ Ws/cm2 with an ultraviolet transmittance of 65% at peak day flow, and must be able to hydraulically pass the peak hour flow with the largest bank out of service. The existing system can provide 30,000 µ Ws/cm2 with an ultraviolet transmittance of 65% for 0.50 MGD with the largest bank out of service. This flow rate is less than the projected peak day capacity. The system does not have sufficient capacity for the 20-year planning period. For the past two years, the existing system has produced effluent that ranges from 10-83 fecal coliform colonies per 100 mL. This level is close to the permit limits, and this indicates that the existing system is approaching its capacity and will need to be replaced. It is recommended that a new larger UV system be installed for disinfection. EFFLUENT PUMP STATION Process Description Typically the effluent flows to the river by gravity but inadequate hydraulic head exists during high river flow events. The effluent pump station consists of two wet wells. The first wet well contains the pumps and the second allows the water to rise to a higher hydraulic level, a check valve prevents the water from flowing back to the pumps. During high river levels the pumps pump the effluent to the second wet well and the water then flows by gravity to the river. Design criteria for the effluent pump system are provided in Table 5-9.

TABLE 5-9 Effluent Pump System Design Criteria

Effluent Pump System Pump Type Submersible Quantity of Pumps 2 Capacity Each 300 Horsepower 5 Structural The soil around the effluent pump station has settled. However, this has not damaged the structure. The effluent pump station is in good structural condition and is suitable for the twenty year planning period. Mechanical The settling of the soil around the pump station has severed the electrical power to the pump station, and the pump station is inoperable.



Capacity The pump station must be able to pump peak hour flow (PHF) to the river with the largest pump out of service. The existing pumps are 300 gpm (0.432 MGD) which are less than the projected PHF. The existing pump station does not have sufficient capacity for the 20- year planning period. New larger pumps are recommended to increase the capacity of the lift station. OUTFALL Process Description The effluent pipe is a 12-inch PVC pipe with a slope of 0.0022 ft/ft. The outfall is a 10-inch HDPE pipe with a slope of 0.175 ft. The outfall does not have a diffuser and is typically in 5 to 6 feet of water. The effluent flows to the river by gravity during normal river levels and is pumped to the river during high river levels. Structural The outfall was constructed in the 1999 and is in good condition. Capacity The sewer must be able to pass the PHF. With the existing slopes, the effluent sewer and outfall capacity is 1.1 MGD which is adequate for the 20-year planning period. SOLIDS TREATMENT FACILITIES AEROBIC DIGESTER Process Description The City wastes sludge from the clarifiers to the aerobic digester. The digester is an open top tank. Coarse bubble diffusers add oxygen to the sludge. The sludge storage has a telescoping valve to allow for the supernatant to be decanted to increase the solids concentration of the sludge storage. The decanted liquid flows to the sludge conditioning tank or directly to the oxidation ditch. The sludge is pumped to the drying beds. Table 5-10 provides the system design criteria for the aerobic digester system.



TABLE 5-10

Aerobic Digester Design Criteria Aerobic Digester System Storage Tank Quantity 1 Volume 28,000 ft3, 210,000 gal Dimensions 40 ft diameter, 21 feet SWD Blower (VFD) 240-600 scfm @ 10 psig Aeration Coarse Bubble Diffusers Sludge Pump 100 GPM Horsepower 40 Structural The concrete tank is in good condition. The enclosures for the sludge pump and the blower require maintenance such as painting and minor modifications. Mechanical The sludge pump and the blower are in satisfactorily condition for the 20-year planning period. The telescoping valve in the tank is broken and the system can not decant. The blower VFD is inoperative. The Blower VFD should be replaced to allow the WWTF to save energy. Capacity The aerobic digester system will be evaluated to see if has the ability to be classified as a process to significantly reduce pathogens (PSRP) when accommodating the entire projected maximum month sludge loadings. The PSRP requires a solids retention time (SRT) between 40 days at 20°C and 60 days at 15°C. The open top aerobic digester will not be able to maintain 20°C but might be able to maintain 15°C. To be classified as a PSRP process the sludge storage tank will require at least 60 days of storage. Assuming a solids concentration of 2%, the total solids in the existing aerobic digesters is calculated as follows:

Total Solids in Digesters = (0.210 MG)(20,000 mg/L)(8.34) = 35,049 lb The equation used to calculate the mass of waste activated sludge per day, Px, in the oxidation ditch section of this report is used to determine the mass of solids to be removed from the digesters. With a biodegradable VSS production of 294 lb/d, non-biodegradable solids of 218 lb/d, and non-volatile suspended solids of 218 lb/d, and assuming 40 percent biodegradable VSS destruction in the aerobic digesters, the mass of solids to be removed is:

Mass of Solids Wasted = (294 lb/d)(0.6) + 218 + 218 = 613 lb/d



The SRT is then estimated:

SRT = (Mass of solids in the digester)/(mass flow rate of solids leaving the digester) SRT = (35,049 lb)/(613 lb/d) = 57 days

Therefore, the volume of the existing aerobic digester will be sufficient to produce a Class B biosolid suitable for land application when operated at a solids concentration of 2% and if the temperature is maintained above 20°C. For most of the year the tank will not be able to maintain 20°C, therefore air drying will be required to meet Class B biosolids requirement. The total aerobic digestion oxygen demand is calculated below assuming 40 percent VSS destruction and a VSS fraction of 80%. Carbonaceous O2 Demand = 1.42 lb/lb(feed sludge VSS lb/d)(% VSS destruction)

= 1.42 lb/lb(294 lb/d)(0.4) = 167 lb O2/d

Nitrogenous O2 Demand = 4.57 lb/lb(N/VSS destroyed)(feed sludge VSS) *(%VSS destroyed)

= 4.57 lb/lb(0.12 lb/lb)(294 lb/d)(0.4) = 61 lb O2/d

Total O2 Demand = Carbonaceous O2 Demand + Nitrogenous O2 Demand = 228 lb O2/d

Oxygenation equipment is specified based upon standard oxygen transfer rate (SOTR), the oxygen transfer rate in clean 20oC water with no suspended solids. The SOTR is calculated as follows:

20

20

024.1

T

S

OSTH

C

CCSOTRAOTR

Where: a = oxygen transfer correction factor, 0.6 (typical for this diffused aeration

equipment) b = salinity surface tension factor, 0.95 CSTH = dissolved oxygen concentration at operating temperature and elevation, = 8.08 mg/L CS20 = dissolved oxygen concentration at 20oC and 1 atm, 9.08 mg/L CO = operating dissolved oxygen concentration, 2 mg/L T = 20oC



Thus the total oxygen demand is 616 lb/day. Assuming a coarse bubble efficiency of 10 percent, the required airflow is then:

Air flow = 616 lb O2/d/(1440 min/d)(0.0173 lb O2/scfm)(0.10) Air flow = 247 scfm

The air required for mixing the aerobic digester is calculated with the mixing requirement of 0.02 scfm/ft3:

Mixing Requirement = (28,000 ft3)(0.20 scfm/ft3) = 560 scfm The existing blower provides 600 scfm of airflow at 10 psig, therefore, the existing aerator has sufficient capacity. SLUDGE DRYING BEDS Process Description The City wastes sludge from the aerobic sludge storage tank to the sludge drying beds. The sludge drying beds are paved beds without under drains. If the aerobic sludge storage tank cannot maintain 20oC, then the biosolids can meet the pathogen control requirement for Class B biosolids by meeting the requirement for air-drying. According to WAC 173-308-170, the air-drying requirements stipulate that the biosolids must be dried for a minimum of three months. During two of the three months, the ambient average daily temperature must be above 0oC. Vector attraction requirements will be met with sludge drying beds by drying the solids to 95 percent. The sludge drying beds consist of 15,000 square feet of paved undrained drying beds. Structural The asphalt drying beds are in good condition. Mechanical The asphalt drying beds have no mechanical deficiencies. Capacity The Criteria for Sewage Works Design states that the maximum drying bed loading rate for activated sludge is 15 lbs/ft2/yr. The total projected solids wasted are 613 lb/day or 223,745 lb/yr. The sludge drying beds are 15,000 ft2 for a loading rate of 14.9 lbs/ft2/yr. This rate meets the Ecology maximum loading rate.



All water must leave the bed by evaporation because the drying beds do not have under drains. The solids wasted at 2% solids will equal 3,672 gpd or 1.34 MG/year. The Mabton area historical average rainfall is 6.7 inches and 37 inches of evaporation each year. The drying bed area required is 74,052 ft2 to evaporate 1.34 MG of water each year. Without under drains the sludge drying beds are too small. Chapter 6 will evaluate alternatives to increase solids handling capacity. ELECTRICAL SERVICE The WWTF has a 480 volt 3 phase electrical service serving a 400 amp main distribution switchboard. This switchboard serves existing panelboards and motor control centers located throughout the plant. The WWTF has a standby power engine generator (100 kW/125 kVA @ 480 volt, 150 amp maximum capacity) which currently serves all of the plant loads. The distribution equipment and standby generator appear to be in good condition for use during the 20 year planning period. The current utility metering information for the plant shows a peak metered load for the year of 69 kW. Assuming a power factor of 0.8, the current peak 15 minute demand metered load is 86.25 kVA or 103.87 amps. Chapter 6 will analyze the generator capacity for additional loads caused by improvements. SCADA SYSTEM The WWTF has a SCADA system with a software alarm dialing and a separate hardware backup alarm dialer. The SCADA system has not been updated for approximately ten years. The control software, the PC operating system software, and the PC running the software are out of date. Several control functions are inoperative such as controlling the oxidation ditch rotor speed control and some plant motors do not restart on generator power. The SCADA system will require modification and hardware/software updates to be utilized for the 20-year planning period. LAB AND MAINTENANCE BUILDING The laboratory has adequate room to perform all of the required analysis. The building is in overall good condition, but requires some maintenance work such as:

Painting HVAC replacement New hot water tank New windows and doors to keep dust out of the lab Need a laboratory glass washer Need equipment for making distilled water



Converting the area by the electrical room to office space, for storage and office space

Backflow prevention devices for the building require modification. NONPOTABLE WATER SYSTEM The WWTF has a non-potable water system that is provided water from the City’s water system through a backflow preventer. The only process unit that utilizes the water is the fine screen for washing of the screening. The other use for the non-potable water is wash down water supplied from frost free hydrants. The clarifiers need spray bars to help control scum. Chapter 6 evaluates the use of wastewater effluent as non-potable water instead of water from the City’s water system. SUMMARY OF EXISTING FACILITIES The analysis has determined that the following facilities do not have the treatment capacity for the projected flows and loadings for the 20-year planning period. Figure 5-4 graphically presents the improvements required at the WWTF.

Fine Screen Influent Parshall Flume Oxidation Ditch Oxidation Ditch Rotors Secondary Clarifier No. 1 Ultraviolet Disinfection System Effluent Pump Station Sludge Drying Beds

The analysis has determined that the following are functionally obsolete.

Sludge conditioning tank Secondary Clarifier No.1 Rock Trap Comminutor

The existing permit requires the Plan to evaluate increasing oxygen and lowering the temperature of the effluent. Based on the analysis in this Chapter, a summary of the deficiencies other than capacity issues at the City’s WWTF is listed below. Additional improvements required to meet future capacity needs will be developed in Chapter 6.

1. Sewer Collection System



a. Complete an infiltration and inflow study of the sewer system including a video of the sewers to asses the condition of the sewer collection system.

2. Headworks

a. No grit removal is provided. b. The headworks is not equipped with piping to drain the channels for

cleaning.

3. Sludge Conditioning Tank a. The sludge conditioning tank has only one biological selector zone. b. The sludge conditioning tank is oversized resulting in a low F/M ratio,

which could prevent it from producing good settling solids. 4. Oxidation Ditch

a. The automatic speed controller for the rotors is not operational.

5. Secondary Clarifier a. The clarifier weirs are not level. b. The clarifiers do not have spray bars. c. Secondary Clarifier No. 1 scum arm is broken.

6. RAS/WAS Pumps

a. The heaters in the enclosures are not operational. b. One RAS pump casing is cracked. c. Enclosures are too small and make maintenance difficult. d. WAS pumps become air bound when pumping scum.

7. Ultraviolet Disinfection

a. The equipment is no longer manufactured and it is hard to get parts.

8. Aerobic Sludge Storage Tank a. The enclosures for the sludge pump and the blower need minor

maintenance such as painting and heater repairs. b. Blower VFD does not operate. c. Decant mechanism is inoperative.

9. SCADA

a. The software needs to be updated to current versions. b. The computer needs to be replaced. c. The programming requires modifications to control functions.

10. Lab and Maintenance Building

a. Painting. b. HVAC replacement. c. New hot water tank.



d. New windows and doors to keep dust out of the lab. e. A laboratory glass washer is needed. f. Need equipment for making distilled water. g. Converting the area by the electrical room to office space will add to the

area in the lab. h. Backflow prevention devices for the building require modification.

11. Nonpotable Water System

a. The existing non-potable water system is supplied water from the City’s water system. An evaluation should be completed to determine if it is cost effective to replace the City’s portable water with wastewater effluent.

CHAPTER 6

WWTF IMPROVEMENTS


CHAPTER 6

WASTEWATER TREATMENT FACILITY IMPROVEMENTS

INTRODUCTION This chapter identifies and describes recommended improvements to the existing facilities, and evaluates alternative options for treating the flows and loadings. The goal of this evaluation is to select an alternative that is reliable, cost effective, produces an effluent that complies with the NPDES permit, and generates biosolids that can be cost effectively managed in accordance with federal and state regulations. It is assumed that the treated effluent will continue to be discharged to the Yakima River, and the residual solids will be land applied at a site permitted for that purpose. COLLECTION SYSTEM IMPROVEMENTS Chapter 5 recommends an infiltration and inflow study to determine the condition of the sewer collection system and to determine the amount of infiltration and inflow. The study estimated cost is $55,000 and would include the following:

Videotape the sewer collection system to determine the condition of the pipes. Smoke testing to determine locations of illegal storm water connections. Smoke

testing consists of blowing smoke into the collection system with a fan and visually determining where the smoke exits the system. Smoke testing is a method to determine if a storm water system is connected to the sewer collection system.

Perform flow observations at manholes to determine where in the system infiltration and inflow is occurring.

Field inspection of the manholes to determine the condition of the manholes. WWTF IMPROVEMENT ALTERNATIVE This chapter determines the method to increase the capacity of the following processes that have insufficient capacity or functionally obsolete as determined in Chapter 5:

Fine Screen Influent Parshall Flume Sludge Conditioning Tank (functionally obsolete) Oxidation Ditch Oxidation Ditch Rotors Secondary Clarifier No. 1 (functionally obsolete)



Ultraviolet Disinfection System Effluent Pump Station Sludge Drying Beds

This chapter evaluates methods to increase dissolved oxygen in the effluent and lower the effluent temperature as required by the existing permit. In addition, Chapter 5 determined that denitrification was required to recover alkalinity. Other minor improvements as determined in Chapter 5 will be addressed in this analysis. Headworks Improvements The existing screen and Parshall flume do not have capacity for the planning period. The WWTF does not have a method to remove grit. It is recommended that a new headwork be constructed. The headworks will consist of a new fine screen, grit channels, Parshall flume and relocating the existing influent sampler. The new screen to remove manufactured inerts will be sized based upon a design peak hour flow to the facility. For the 20-year planning period, the peak hour flow is 0.87 MGD. The Parshall flume must measure flows from existing minimum flow (.075 MGD – 50% of current AAF) to future PHF (0.87 MGD). A 6-inch Parshall flume has a range from 0.035 to 2.53 MGD. Gravity grit channels are typically designed for a velocity of 1 ft/s at design PHF. The Parshall flume controls the water level in the grit channel (0.77 feet at PHF of 0.87 MGD). A 1.5 foot wide channel will produce 1 ft/s at a PHF. To remove 65-mesh grit from the flow, the channels must be long enough to allow the grit to settle, at a theoretical particle settling velocity of 3.8 ft/min. The depth of flow at PHF is 0.77 feet, based on the Parshall flume; the required hydraulic detention time of the channel must be at least 0.77 ft / 3.8 ft/min, or 0.2 minutes. To account for removal inefficiency due to inlet and outlet turbulence, an additional 50 percent of theoretical detention time is required. These criteria result in a required theoretical detention time of 0.3 minutes at peak hourly flow, or 18 seconds. At 1 ft/sec and a detention time of 18 seconds results in a minimum channel length of 18 feet, a 20 foot channel will be provided. A two sided building will be provided to provide weather protection for the headworks. A fully enclosed building will not be provided because the space inside a fully enclosed building is classified as an explosion hazard area, which would greatly increase the cost of the building.



The design criteria for the headworks are provided in Table 6-1.

TABLE 6-1

Headworks Design Criteria

Fine Screen Quantity 1Type Mechanically Cleaned Fine ScreenScreen Opening ¼ inchScreen Diameter 10 inchCapacity 1.14 MGDMotor Size 2 hpMaximum Headloss 12 inchesManual Bar Screen (bypass) 2 ft channel width, 3/8” bar spacing

Gravity Grit Channel Quantity 2Design Velocity 1 ft per secondChannel Length 20 ftChannel Width 1.5 ftChannel Depth 2.5 ftSide Water Depth 0.77 ft

Parshall Flume Throat Width 6 inchesRange 0.035 to 2.53 MGDWater Depth 0.1-1.5 feet

Sampler (Existing) Type Refrigerated Composite

Building Type Two Sided Canopy

BIOLOGICAL TREATMENT The oxidation ditch and rotors do not have sufficient capacity for the 20-year planning period. The sludge conditioning tank (biological selector) is oversized and has only one compartment which limits its ability to produce good settling solids. Future effluent limits will probably require nitrogen removal (denitrification) and possibly phosphorus removal. Denitrification will be included in the biological treatment because it is required to recover alkalinity and prevent effluent pH permit limit violations. Phosphorus removal will not be incorporated in the biological treatment because phosphorus limits are not anticipated for a minimum of 10 to 15 years, based on conservations with Ecology.



Biological Treatment Process Alternatives The Department of Ecology requires that alternatives be evaluated for a facility plan as described in WAC 173-240-050. This plan will evaluate six alternatives for increasing the capacity of the biological treatment process. The six alternatives to increase the biological treatment capacity at the WWTF are described in the following sections Alternative No. 1 – Supplement Existing Oxidation Ditch with New Aeration Basin and Anoxic Basin This alternative consists of the following components:

New Headworks as previously described. New bioselectors for providing the environmental conditions necessary to

promote the growth of floc-forming microorganisms. New anoxic tank for the denitrification and the recovery of alkalinity. New aeration basin for biological treatment including fine bubble diffuses and

two aeration blowers for the addition of oxygen to the tank. Reuse of the oxidation ditch for additional biological treatment. Secondary clarifiers including the construction of new Secondary Clarifier No. 3.

The existing Secondary Clarifier No. 1 will be abandoned. New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the

effluent. Additional Sludge Drying Beds

Figure 6-1 presents the layout for this alternative. Alternative No. 2 – New Aeration Basin and Abandon Existing Oxidation Ditch This alternative consists of the following components:


promote the growth of floc-forming microorganisms. New anoxic tank for the denitrification and the recovery of alkalinity. New aerobic basin for biological treatment, including fine bubble diffusers and

two aeration blowers for the addition of oxygen to the tank. This basin will provide all of the biological treatment because the oxidation ditch will be abandoned. The new aeration basin will be constructed as two tanks each capable of treating one-half of the flow.

Abandonment of the oxidation ditch.



Secondary clarifiers including the construction of new Secondary Clarifier No. 3. The existing Secondary Clarifier No. 1 will be abandoned.

New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the


Figure 6-2 presents the layout for this alternative. Alternative No. 3 – Supplement Existing Oxidation Ditch with New Aeration Basin and operate existing Oxidation Ditch with Both an Aerobic and Anoxic Zones by Cycling the Oxidation Ditch Rotors This alternative consists of the following components:


promote the growth of floc-forming microorganisms. New aeration basin for biological treatment including fine bubble diffuses and

two aeration blowers for the addition of oxygen to the tank. Reuse of the oxidation ditch for biological treatment. The oxidation ditch rotors

will be cycled on and off to create aerobic and anoxic conditions in the ditch. During anoxic conditions, denitrification and recovery of alkalinity will occur.

Secondary Clarifiers including the abandonment of Secondary Clarifier No. 1 and the construction of new Secondary Clarifier No. 3.

New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the


Figure 6-3 presents the layout for this alternative. Alternative No. 4 – Membrane Bioreactor This alternative consists of the following components:

New Headworks as previously described but fine screen opening (perforation) size reduced to 3 millimeters.

Modify existing Secondary Clarifier No. 1 to convert it to anoxic basin. Modify existing Secondary Clarifier No. 2 to convert it to a pre-aeration basin. New membrane bioreactor basin with membrane filtration and aeration blowers.



Abandon oxidation ditch. New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the


Figure 6-4 presents the layout for this alternative. Alternative No. 5 – Recirculating Gravel Filter with Interceptor Tanks This alternative is different than the previous alternatives because influent solids must be removed prior to biological treatment process (gravel filter) to prevent the plugging of the filter. Also, unlike the previous alternatives, the biological treatment does not produce waste activated sludge that must be treated and disposed. This alternative consists of the following components:

Install interceptor tanks at each house and commercial connection in the City to remove influent solids.

Construct Recirculating Gravel Filter with recirculation tank. New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the

effluent. Abandon oxidation ditch, clarifiers, aerobic digester and sludge drying beds.

Figure 6-5 present the layout for this alternative. Alternative No. 6 – Recirculating Gravel Filter with Primary Clarifier This alternative is similar to Alternative No. 5 except that primary clarifiers are utilized to remove influent solids (primary solids). This alternative involves the treatment and disposal of primary solids instead of secondary solids as required in the first four alternatives. This alternative consists of the following components:

New Headworks as previously described. Convert existing secondary clarifiers to primary clarifiers. Construct Recirculating Gravel Filter with recirculation tank. New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the

effluent. Convert existing aerobic digester to treat primary solids.



Abandon oxidation ditch. Figure 6-6 presents the layout for this alternative. Alternative No. 7 – Natural Wastewater Treatment Alternative This alternative will utilize a natural wastewater treatment to provide for treatment of the wastewater with low energy use. This alternative is evaluated in Appendix F Mabton Green Projects Report.

New Headworks as previously described. Abandon most of the existing WWTF. New 20-acre facultative lagoon. New 8-acre surface flow wetland with aeration. Attached growth polishing process for ammonia removal Recycle Pump Station with moving bed bioreactor for nitrogen removal New ultraviolet disinfection equipment. Effluent pump station with new pumps. New effluent re-aeration tank to raise the dissolved oxygen concentrations of the

effluent. Appendix F presents the layout for this alternative. Alternative Comparison Preliminary operation and maintenance costs have been developed for each alternative utilizing the cost to operate the existing WWTF as a starting point. The operation and maintenance cost presented is the cost to operate the entire sewer utility. Currently the sewer utility operation and maintenance cost is $202,900 per year. Table 6-2 presents a summary of the operation and maintenance cost for the alternatives. Preliminary design criteria and capital costs have been developed for each alternative. To make each alternative comparable all cost estimates includes sludge drying beds for solids treatment if solids treatment is required. The cost estimate includes all treatment process to make a fully functional WWTF. Table 6-3 presents the capital cost and the 20-year present worth cost of all the alternatives. Detailed cost estimates are presented in Appendix D. Alternatives No. 1, 2 and 3 have similar costs for capital, operation and maintenance costs and present worth costs. Alternatives No. 4, 5, 6, and 7 have significantly higher capital costs and present worth costs than the first three alternatives. Although Alternatives 5, 6, and 7 have lower operation and maintenance costs, the capital costs of these alternatives are significantly greater, resulting in a higher 20-year present worth in comparison to the other alternatives.



The following provides a discussion of the advantages and disadvantages of each alternative.

Alternative No. 1, 2 and 3 – These alternatives are similar in operational

complexity to the existing WWTF. These alternatives remove nitrogen and can be upgraded in the future to remove phosphorus.

Alternative No. 4 – This is the most complex facility to operate. This alternative removes nitrogen and can be upgraded in the future to remove phosphorus. This alternative has the highest energy costs of all alternatives.

Alternative No. 5 and 6 – These alternatives are the simplest to operate. However, these alternatives do not remove nitrogen and will be difficult to upgrade for the removal of nitrogen and phosphorus. This alternative may not meet the ammonia permit limit on a consistent basis during cold weather periods. These alternatives have the lowest energy cost of all alternatives.

Alternative No 7 – This alternative is simple to operate. This alternative may not meet the ammonia permit limit on a consistent basis during cold weather periods. This alternative has low energy cost. The City will be required to manage wetland vegetation which could significantly add to the operation and maintenance cost. The denitrification process requires an external carbon source which could significantly add to the operation and maintenance cost. The proposed future phosphorus process has not been accomplished in a lagoon system and may not be a feasible method for meeting future phosphorus limits.

Alternative No. 4 is not recommended because it has the highest capital costs, highest operation and maintenance costs, the highest energy usage and is more complicated to operate. Alternatives No. 5 and 6 are not recommended because of the high capital costs, lack of nitrogen removal, difficulty to upgrade for phosphorus removal and the lack of reliability in meeting the ammonia permit limit. Alternative No. 7 is no not recommended because of the high capital costs, difficulty to upgrade for phosphorus removal and the lack of reliability in meeting the ammonia permit limit.



TABLE 6-2

Annual Operation and Maintenance Costs for Treatment Alternatives

Existing

Alt. 1 New Anoxic Tank,

New Aeration Basin and

Reuse Oxidation

Ditch

Alt. 2 New Aerobic

Basin Abandon Oxidation

Ditch

Alt. 3 New Aerobic Basin &

Oxidation Ditch Anoxic

/Aerobic

Alt. 4 Membrane Bioreactor

Alt. 5 RGF with

Interceptor Tanks

Alt. 6 RGF with Primary

Clarifier

Alt. 7 Natural

Wastewater Treatment (3)

Salaries & Benefits $104,000 $157,000 $157,000 $157,000 $157,000 $79,000 $105,000 $105,000 Repairs/ Maintenance $16,400 $12,000 $12,000 $12,000 $16,000 $6,000 $8,000 $8,000 Miscellaneous $23,900 $24,000 $24,000 $24,000 $24,000 $24,000 $26,000 $24,000 Sewer Operating Supplies $13,000 $23,000 $23,000 $23,000 $26,000 $10,000 $12,000 $10,000 Admin/ Professional Services (1) $25,600 $26,000 $26,000 $26,000 $26,000 $20,000 $20,000 $20,000 Energy $18,500 $28,000 $24,000 $24,000 $40,000 $7,000 $11,000 $13,000 Membrane Replacement Cost $0 $0 $0 $0 $32,000 $0 $0 $0 Interceptor Tank Pumping Cost $0 $0 $0 $0 $0 $20,000 $0 $0 Total $202,900 $270,000 $266,000 $266,000 $321,000 $166,000 $182,000 $180,000

(1) Average cost for the years 2008 to 2010. (2) Includes cost of biosolids disposal off site. (3) Does not include cost for wetland vegetation management or supplemental carbon for denitrification



TABLE 6-3

Alternative Capital and Present Worth Cost

(1) Based on the use of sludge drying beds for the solids treatment. (2) From Table 6-2. (3) Present Worth Cost = Capital Cost + 20-year present worth cost of the operation and maintenance cost at 4.0% interest rate.

Alt. 1 New Anoxic Tank,

Aeration Basin and Reuse

Oxidation Ditch

Alt. 2 New Aerobic Basin

Abandon Oxidation Ditch

Alt. 3 New Aerobic Basin & Oxidation

Ditch Anoxic/Aerobic

Alt. 4 Membrane Bioreactor

Alt. 5 RGF with Interceptor

Tanks

Alt. 6 RGF with Primary Clarifier

Alt. 7 Natural Wastewater Treatment

Capital Cost (1) $5,638,000 $6,255,000 $5,773,000 $7,260,500 $10,313,000 $9,038,000 $10,587,000 Operation and Maintenance Cost (2) $270,000 $266,000 $266,000 $321,000 $166,000 $182,000 $180,000 Present Worth Cost (3) $9,307,000 $9,870,000 $9,388,000 $11,623,000 $12,569,000 $11,511,000 $13,033,000



Alternatives No. 1, 2 and 3 are similar in complexity, operation and maintenance costs and future ability to upgrade. Of these three alternatives, Alternative No. 1 is recommended because it has lower capital cost and lower twenty year present worth cost. Also Alternative No. 1 is more stable process than Alternative No. 3. It is possible that Alternative No. 3 will require carbon addition to ensure denitrification under all circumstances. The City decided to construct the upgrades to the WWTF in two phases. The two phases are:

Phase 1 – Utilize Alternative No. 1 to upgrade of the existing wastewater treatment facility to reliably meet the requirements of the NPDES permit.

Future Phase 2 – In addition to constructing Phase 1 facilities to comply with the NPDES permit, the City proposes to construct a natural treatment polishing process. The purpose of the natural treatment polishing process is environmental enhancement for fisheries and wildlife, environmental education and economic development. The natural treatment polishing process will consists of a polishing pond or wetland similar to the 8-acre wetland that was part of Alternate No. 7 Natural Wastewater Treatment as discussed in the Mabton Green Projects Report in Appendix F. This wetland may also be utilized for future storm water treatment for the City or be constructed for wetland mitigation banking.

Phase 1 Alternative biological process will consist of bioselectors, anoxic basin, new aeration basin and the oxidation ditch. The anoxic basin purpose is to recover alkalinity by denitrification. The following sections provide the sizing for the Alternative No. 1 biological treatment process. Biological Selectors For biological selection, a relatively high F/M (food to microorganism ratio) should be utilized to increase the concentration of readily available (soluble) BOD5. The biological selector should have two zones, F/M of 6 g BOD/g MLSSd in each zone and an overall F/M ratio of 3 g BOD/g MLSSd. With a design MLSS of 3,500 mg/L, each zone in the biological selector is 4,000 gal (1,000,000 x 697 lb/day / (3,500 mg/L x 8.345 x 6)). Anoxic Zone The biological reduction of nitrates to nitrogen gas will take place in the anoxic zone. In addition to removing nitrogen from the wastewater, the anoxic zone adds several other advantages to the treatment process. It improves overall process stability, recovers a



portion of the alkalinity that is consumed during nitrification in the oxidation ditch (to be discussed later), reduces aeration requirements (i.e. saves power) by using nitrate in lieu of oxygen as an electron acceptor, and, finally, it provides some additional selection against filamentous bacteria. The mixture of influent wastewater and return activated sludge (RAS) will enter the anoxic zone together with effluent from the oxidation ditch. This effluent contains a high concentration of nitrates as a result of biological nitrification in the aerobic zone. The first step in sizing the anoxic zone is to find the active biomass in the MLSS in the anoxic zone, which will be the same as in the oxidation ditch. The equation describing the active biomass is as follows:

Xb=[Q(SRT)/V] x [Y(S0-S)/(1+kd,t(SRT))] Where: Xb = active biomass in aeration basin, mg/l (to be determined) Q = design flow = 0.290 MGD SRT = solids retention time in aerobic = 14 days (determined in the aerobic section) V = volume of aerobic zone = 0.35 MG (determined in the aerobic section) Y = heterotrophic cell yield = 0.40 lb/lb bCOD (typical for domestic wastewater) S = influent biodegradable COD (bCOD), taken as 1.6 x influent BOD5 = 461 mg/l (1.6 x 697 lbs/day / (0.29 MGD x 8.345) S0 = effluent bCOD, taken as 1.6 x effluent BOD5 = 8 mg/l (1.6 x 5 mg/L discharge) kd,t = endogenous heterotrophic decay coefficient at temperature “t” =kd,20x1.04(t-20)

kd,20 = 0.12/day (typical for domestic wastewater) t = 8oC (assumed lowest temperature in the aerobic zone during the winter) kd,8= 0.12x1.04(7-20) = 0.075/day

Thus, the active biomass concentration in the mixed liquor would be as follows:

Xb = (0.290x14/0.35) x [0.4(461-8)/(1+0.075x14)] = 1025 mg/l The next step is to determine the internal recycle (IR) ratio. The internal recycle returns nitrified effluent to the anoxic zone so that the nitrates can be reduced to nitrogen gas and released to the atmosphere. The amount of nitrates that will be returned from the oxidation ditch to the anoxic zone depends on the amount of nitrates that will be discharged in the effluent. As will be shown in the next section, the oxidation ditch will be designed for an effluent ammonia concentration of 1 mg/l. Also, the effluent suspended solids will contribute a small amount of organic nitrogen. The plant effluent will have a suspended concentration of less than 5 mg/l. Usually, 12 percent of the suspended solids consist of organic nitrogen. Thus, 0.6 mg/l of organic nitrogen would be present in the plant effluent.



The design total nitrogen limit is 10 mg/l in the treatment plant effluent. Since the WWTF effluent nitrogen will consist of ammonia, organic nitrogen, and nitrates, the allowable effluent nitrate concentration should be limited to 8.0 mg/l. The IR ratio is defined as the IR flow divided by the influent flow and is determined by the following equation:

IR = (NOx/Ne) – 1.0 – R Where:

NOx = oxidation ditch nitrate concentration resulting from nitrification of influent TKN = 51 mg/l (determined in the next section) Ne = effluent nitrate concentration = 8.0 mg/l (discussed above) R = RAS ratio = 0.49 (determined in the next section)

The internal recycle ratio would, thus be as follows:

IR = (51/8) – 1.0 – 0.5 = 4.9 An IR ratio of 4.9 will result in an IR flow of 4.9 x 0.29 MGD = 1.416 MGD = 983 gpm. The next step in sizing the anoxic zone is to determine the mass of nitrates that are fed to the anoxic tank. Nitrates are fed in both the IR flow and the RAS flow. Thus the total flow feeding nitrates to the anoxic zone is 0.29 x (4.9+0.5) = 1.55 MGD. The concentration of nitrates in this flow is 8.0 mg/l, for a total mass of 1.55 x 8.0 x 8.34 = 105 lbs/day. This is the total mass of nitrates that will have to be converted to nitrogen gas in the anoxic zone. The last step in sizing the anoxic zone is to determine the appropriate detention time required to remove the nitrates introduced to the anoxic zone and then calculate the volume. This is an iterative process (“trial-and-error”), and only the last iteration is presented herein. It has been determined that the rate of denitrification at 20oC (SDNR20) is a function of the ratio of influent BOD to the mass of the active biomass in the anoxic basin (F/Mb). The relationship is given on Figure 8-23 in Wastewater Engineering, Treatment and Reuse, Fourth Edition, Metcalf and Eddy, 2003. At an active biomass concentration of 1,025 mg/l, and an influent BOD of 1,152 lbs/day:

F/Mb = QSo / Vnox /Xb

Q = Design Flow 0.29 MGD So = Influent BOD mg/L Vnox = Volume of Anoxic Zone



Xb = Anoxic zone biomass concentration 1,025 mg/l

F/Mb = 0.29 x 288 /.085 / 996 = .99 Figure 8-23 in Metcalf and Eddy (referenced above) gives a SDNR20 of 0.21 lb NO3/lb active biomass per day. SDNR vary with temperature based on the following relationship:

SDNRt = SDNR20 x 1.026(8-20). This gives an SDNR8 of 0.154 lb NO3/lb active biomass per day. The active biomass in the anoxic zone is Mb = 0.085 x 1,025 x 8.34 = 727 lbs. Thus, the anoxic zone is capable of removing Mb x SDNR6 = 727 x 0.150 = 112 lbs of nitrates per day, which is slightly greater than the mass of nitrates that is required to be removed. The detention time for the anoxic zone has been determined to be 7.0 hours, based on treatment plant influent flow (.085 MG x 24 hrs/day / 0.29 MGD). The use of nitrates in the anoxic zone as an electron acceptor will reduce the aeration requirements in the oxidation ditch. The aeration requirements will be reduced by 2.86 pounds of oxygen per pound of nitrates removed in the anoxic zone. Since 105 lbs of nitrate will be removed per day, the required oxygen input to the oxidation ditch can be reduced by 2.86 x 105 = 299 lbs oxygen per day. Oxygen requirements are discussed in detail in the next section. Alkalinity recovery in the anoxic zone is also discussed in the next section. Aerobic Zone Aerobic zone capacity requirements are dependent on three major design criteria. These criteria are solids retention time (SRT), net heterotrophic and autotrophic yields, and design mixed liquor suspended solids (MLSS) concentration. SRT is the criteria of greatest importance for nitrification. The net specific growth rate of the nitrifying biomass is an order of magnitude lower than that of carbon oxidizing bacteria and is therefore used as the basis for determining the SRT of the aerobic zone system. Also, the SRT used to calculate the required value for nitrification must be the aerobic SRT since nitrification only occurs under aerobic conditions. SRT Calculation The first step is to calculate the maximum specific nitrifier growth rate (n,m), decay rate (kdn), and ammonia half saturation coefficient (KN) at the winter design temperature of 8oC (coldest weekly average oxidation ditch temperature 2006-2010) using the following equations.

n,m,8 = (n,m) x (t-20) = (0.9/d) x (1.0728-20) = 0.391/d



kdn,8 = (kdn) x (t-20) = (0.17 mg/L) x (1.0298-20) = 0.121 mg/L KN,8 = (KN) x (t-20) = (0.7 mg/L) x (1.0538-20) = 0.377 mg/L

The numerical values for the various parameters above are typical for domestic wastewater. Assuming an effluent ammonia concentration of 1 mg/L, a dissolved oxygen concentration (DO) of 2.0 mg/L, and an oxygen half saturation coefficient (KO) of 0.5 mg/L, the actual nitrifier growth rate is calculated as follows:

n = (n,m,7)

DOK

DO

NK

N

ON

- kdn,7 = (0.391/d)

0.25.0

0.2

0.1377.0

0.1-

0.121 /d This yields a net specific nitrifier growth rate of 0.106/d, which is then used to calculate the required SRT using the following equation:

SRT = 1/n = 10.3 days Applying a safety/peaking factor of 1.5 to this value, to account for daily fluctuations in ammonia loading, produces a required aerobic zone SRT of 14 days. In order to calculate the aerobic mass required for the design SRT, the net sludge production for the treatment system must first be estimated. Assuming a cell yield of 0.4 lb VSS/lb biodegradable COD (bCOD), an influent wastewater and biomass VSS/TSS ratio of 0.85, and a design temperature of 8oC, the total sludge production can be determined using the following equation:

iTSSiVSS

tdn

xn

td

tdd

tdX XX

SRTk

NOY

SRTk

SRTSSYkf

SRTk

SSYP

85.0185.0185.01 ,,

0,

,

0

Where:

PX = mass of waste activated sludge per day, lb/d (to be determined) Y = heterotrophic cell yield = 0.40 lb/lb bCOD (typical for domestic wastewater) Yn = autotrophic cell yield = 0.12 lb/lb TKN (typical for domestic wastewater) S = mass of influent bCOD, taken as 1.6 x influent BOD5 = 1,115 lb day (697

lb/day x 1.6) So= mass of influent bCOD, taken as 1.6 x effluent BOD5 = 19 lb/day (5 mg/L x

1.6 at 0.290 MGD based on discharge limit of 10 mg/L) fd = fraction of cell mass remaining as cell debris = 0.15 lb/lb (typical for

domestic wastewater)



kd,t = endogenous heterotrophic decay coefficient, d-1 (see below) kdn,t = endogenous nitrogenous decay coefficient, d-1 (see above) SRT = solids retention time of the SRT = 15 days (see above) XiVSS = volatile nonbiodegradable solids, taken as 30% of influent TSS = 218

lb/day (20 % of 727 lb/day TSS) XiTSS = influent nonvolatile suspended solids, taken as 30% of influent TSS = 218

lb/day (20 % of 727 lb/day TSS) t =aerobic zone temperature = 7oC NOx = amount of influent TKN oxidized to nitrate, taken as 80% of influent TKN

= 124 lb/day or 51 mg/L. The values for kd can be determined as follows.

ddkk tnd

/075.004.1/12.0 20820max,8, 0 (typical for domestic

wastewater) The sludge production can then be calculated as follows:

218218

85.014121.01

12412.0

85.014075.01

1419115,1)4.0)(072.0(15.0

85.015075.01

19115,14.0

XP

734XP lb/day This equation yields a total estimated sludge production of 734 lb/day. This equals 1 lb of sludge production for each 1 lb of influent TSS (727 lbs/day), which is typical for an activated sludge process. At the design SRT of 14 days, this waste sludge production results in a required total aerobic mass of 10,985 lbs. Wastewater Engineering (Metcalf & Eddy, 2003) recommends a design MLSS of no more than 4,000 mg/L. With a design MLSS of 3,500 mg/L, the aerobic zone is required to be 0.35 MG (10,985 lbs/3,500 mg/L/8.345 lbs/gal). The existing oxidation ditch is 0.198 MG; therefore the new aerobic zone will be 0.152 MG (0.35 MG – 0.198 MG) Aeration Requirements To biologically oxidize the BOD5 in the wastewater into bacteria and harmless end products, oxygen must be continuously added to the aerobic zone. The required quantity of oxygen consists of a carbonaceous oxygen demand and a nitrogenous oxygen demand. The carbonaceous oxygen demand is calculated as follows: Carbonaceous O2 Demand = S – So – 1.42(Pxbio) Where: S = mass influent bCOD, 1,115 lb/d (461 mg/L at 0.290 MGD from above) So = mass effluent bCOD, 19 lb/d (8 mg/l at 0.290 MGD from above) Pxbio = 0.85(Px)-XiVSS-XiTSS = 0.85(731) - 218 - 218 = 188 lb/d



Therefore, the carbonaceous oxygen demand is 829 lbs O2/day. The nitrogenous oxygen demand is calculated by the amount of nitrogen oxidized to nitrate: Nitrogenous O2 Demand = 4.33(TKN - NH4 - 0.12(Pxbio)) Where: TKN = influent TKN = 155 lb/day NH4 = effluent ammonia, 2.4 lb/d (1 mg/L concentration at 0.290 MGD) Pxbio = 185 lb/d (from above) Therefore, the nitrogenous oxygen demand is 563 lbs O2/day. Oxygen credit from denitrification is 299 lbs O2/day (see anoxic zone calculations for determination). The total oxygen demand is the sum of carbonaceous and nitrogenous oxygen demand minus the oxygen credit from denitrification, or 1,093 lbs O2/day. Applying a safety factor of 1.5 to account for fluctuations in diurnal loads results in a design oxygen demand of 1,429 lbs O2/day, the actual oxygen transfer rate (AOTR). Oxygenation equipment is specified based upon standard oxygen transfer rate (SOTR), the oxygen transfer rate in clean 20oC water with no suspended solids. The SOTR is calculated as follows:

20

20

024.1

T

S

OSTH

C

CCSOTRAOTR

Where: a = oxygen transfer correction factor, 0.9 (typical for this treatment process)

b = salinity surface tension factor, 0.95 CSTH = dissolved oxygen concentration at operating temperature and elevation, = 8.08 mg/L CS20 = dissolved oxygen concentration at 20oC and 1 atm, 9.08 mg/L CO = operating dissolved oxygen concentration, 2 mg/L T = 25oC (maximum weekly average wastewater temperature in recent DMRs) The resulting SOTR is therefore 2,355 lbs O2/day. The new aeration basin and the oxidation are roughly equal in size therefore each must provide approximately one half of the oxygen requirement or 878 lbs O2/day. However the aeration basin will be more heavily loaded and will have a higher demand. A safety factor of 1.2 will be provided for the aeration basin. The aeration basin blowers will provide 1,412 lbs/day of oxygen. In addition, the aeration blowers must supply 45 lbs O2/day for effluent aeration (determined later in the chapter) which corresponds to a total requirement of 1,457 lbs/day



With an efficiency of 2.0 percent per foot for fine bubble diffusers and a submergence of 9.75 feet, a total efficiency of 19.5 percent is obtained. The aerobic zone required air flow is then:

Air flow = 1,457 Lb O2/day/(1,440 min/d x 0.0173 lb O2/scfm x 0.195) Air flow = 300 scfm

The oxidation ditch rotors must supply 49 lbs/hour (1,177 lbs/day / 24 hrs). Chapter 5 indicates that the each oxidation ditch rotors have 47 lbs/hr of oxygen transfer at 9-inch submersion and 72 rpm for a total of 94 lbs/hr of oxygen transfer. The oxidation ditch rotors are adequately sized because the redundancy is provided by the blowers for new aeration basin. Alkalinity Requirements The stoichiometric reaction for the oxidation of ammonia nitrogen to nitrate shows that two moles of hydrogen are produced for every mole of ammonia nitrogen oxidized. In a wastewater treatment system, these hydrogen ions are neutralized by the wastewater’s natural alkalinity (buffering capacity), preventing this acidic condition from significantly reducing the pH within the treatment system. However, if the alkalinity present in the influent wastewater is not sufficient to neutralize the hydrogen ions released during nitrification, the pH within the system will begin to drop. This, in turn, can lead to a significant reduction in nitrification efficiency. pH readings outside the range from 7.2 to 8.0 can have an inhibitory effect on the nitrifying organisms. To determine whether the alkalinity in the wastewater is sufficient, a nitrogen mass balance must be performed. The first step is to determine how much nitrogen is in the waste cell tissue. The biodegradable biological mass of the waste activated sludge (WAS) has been calculated to be 73 lb/d above, assuming that 0.12 lb N/lb of biomass is present results in 9 lb/d of nitrogen present in the waste cell tissue. The mass of TKN oxidized (nitrification) and the mass of nitrates denitrified must be determined in order to calculate how much alkalinity is consumed and how much alkalinity is produced in the process. Following is the equation to determine the quantity of nitrates denitrified: Nitrate Denitrified = TKN - NH4-(0.12Px,bio)-NO3-N Where: Nox = nitrogen oxidized TKN = influent TKN, 155 lb/d, (from above) NH4 = effluent ammonia, 9 lb/d, (from above)



Px,bio = biodegradable biomass wasted, 73 lb/d, (from above) NO3-N = effluent nitrate mass 19 lb/d, (from above, based on 8 mg/L in the

effluent) This equation results in 105 lb/d of nitrate denitrified, it was previously calculated that 124 lb/d of TKN is oxidized to nitrates (nitrification). The amount of alkalinity consumed in the biological processes is calculated as follows:

Consumption = (Nitrification)(7.14 mg CaCO3) – (Denitrification)(3.57 mg CaCO3)

= (105 lbs/d TKN Oxidized)(7.14 mg CaCO3) –

(113 lbs/d· N03-N Denitrified)(3.57 mg CaCO3) The total alkalinity consumed is calculated at 351 lb/d or 145 mg/L at a MMF of 0.290 MGD. An alkalinity of 80 mg/L is required in the oxidation ditch to maintain a pH of 7.2. The total required alkalinity is 225 mg/L (145 mg/L + 80 mg/L). Measured alkalinity in the influent is 370 mg/L. Therefore, the wastewater has sufficient alkalinity. Table 6-4 presents the design criteria for the biological treatment.

TABLE 6-4 Design Criteria Biological Treatment

Biological Selectors Quantity 2Volume Each 4,000 gallonF/M Ratio First Zone 6F/M Ratio Overall 3Anoxic Zone Quantity 2Volume Total 85,000 gallonDetention Time 7.0 hoursInternal Recycle Ratio 4.9Design MLSS 3,500 mg/LAeration Zone Volume Total 380,000 galSRT 14 DaysDesign MLSS 3,500 mg/LSOTR Total 2,355 lbs dayOxidation Ditch Volume 198,000 galRotors 2Oxygen Transfer each rotor 47 lbs/hrAeration Basin



Volume 152,000 galBlowers 2Oxygen Transfer 1,412 lbs/dayAir Flow 300 scfmHorsepower 25 hp Secondary Clarifier Secondary Clarifier No. 1 is functionally obsolete as indicated in Chapter 5. Therefore a new clarifier is recommended. Currently, the existing clarifiers operate mainly in series thus allowing the WWTF to meet the BOD5 permit limit of 10 mg/l. The existing flow is from the higher elevation Secondary Clarifier No. 1 to the lower elevation Secondary Clarifier No. 2. The new Secondary Clarifier No. 3 will be constructed at the same elevation as Secondary Clarifier No. 1, thus continuing the series operation of the clarifiers and allowing the WWTF to continue to meet the low BOD5 permit limit without filtration. Daigger and Roper developed curves published in WEF Manual of Practice No. 8 that correlate the maximum solids loading rate and the underflow (RAS) solids concentration, the RAS underflow pumping rate, and mixed liquor SVI. These curves are presented in Figure 6-7. In order to implement the Daigger and Roper curves to size the new clarifier, the design solids loading rate and mixed liquor SVI must be known. The existing WWTF produces a mixed liquor with an SVI of 150 to 180. A new bioselectors will be installed which should lower the SVI to less than 150 but to be conservative, an SVI of 200 will be utilized. Acceptable solids loading rates for secondary clarifier are typically within the range of 20 lb/ft2/day to 30 lb/ft2/day. Given that the WWTF has a low BOD5 limit, a solids loading rate of 20 lb/ft2/day will be utilized. Given a solids loading rate of 20 lb/ft2/day and a SVI of 200, the Daigger and Roper curves predict a RAS solids concentration of 9,000 mg/L and a required underflow rate of 275 gpd/ft2. Performing a mass balance of the flow to the clarifier and a mixed liquor concentration of 3,500 mg/L leads to a projected overflow rate of 430 gpd/ft2. For a maximum month flow (0.29 MGD), the surface area will be 674 ft2 (0.29 MGD x 1,000,000 /430 gpd ft2) which correspond to a clarifier with diameter of 29.3 feet. A 30 foot clarifier will be utilized to match the existing clarifier size. The maximum solids loading rates for PHF according to the Criteria for Sewage Works Design is 43 lb/ft2/day. As calculated in Chapter 5 the solids loading rate for a 30 foot clarifier is 42 lb/ft2/day. Therefore a 30 foot clarifier is adequately sized for PHF. The clarifiers will provide 100 percent redundancy since one 30 foot clarifier is sized for 100 percent of the flow. The existing Secondary Clarifier No. 2 is slightly shallow (11



feet) and will not perform as well as the new clarifier which will be deeper (14 feet). The new secondary clarifier should only be taken out of service when the SVI is good (<150), lower flow periods or polymer can be added to the oxidation ditch effluent box. As determined in Chapter 5, the Secondary Clarifier No. 2 will require the following modifications to correct some of the minor deficiencies.

Weir leveling Spray bar addition Modification to Secondary Clarifier No. 2 influent well so that it does not trap

scum. Table 6-5 presents the design criteria for the clarifiers.

TABLE 6-5

Design Criteria Secondary Clarifier

Secondary Clarifier Type Circular/Center Feed/Peripheral withdrawalMechanism Continuous Spiral ScraperSecondary Clarifier No. 1 Out of ServiceSecondary Clarifier No. 2 30’ diameter, 707 ft2 surface area, 11 feet

deepSecondary Clarifier No. 3 30’ diameter, 707 ft2 surface area, 14 feet

deepDesign SVI 200Loading Rate at MMF 20 lb/ft2

Loading Rate at PHF 42 lb/ft2

Surface over flow rate (Single Clarifier Operation)

430 gpd/ft2 at 0.29 MGD/MMF

Surface over flow rate (Both Clarifier Operation)

615 gpd/ft2 at 0.87 MGD/PHF

Return Activated Sludge/Waste Activated Sludge The pumps for Secondary Clarifier No. 1 will be moved to a new Secondary Clarifier No. 3. As determined in Chapter 5, the pump stations are adequately sized and the pump stations are packaged pump stations. The sludge pumping system has sufficient capacity for the 20-year planning period. However the sludge pumping system needs improvements to include

New enclosures with heaters for maintenance access. New pump to replace pump with cracked casing.



Addition of non-potable spray bars to wash down scum wells to prevent air binding of pumps while pumping scum.

ULTRAVIOLET DISINFECTION SYSTEM The existing UV system does not have sufficient capacity for the 20-year planning period. A new UV system will be installed in a new channel inside of the existing UV building. The channel will have two banks each capable of providing 100 percent of the dosage for redundancy. A serpentine, finger weir will be installed at the discharge end of the UV disinfection system channel to maintain a constant water depth in the channel. The power level to the UV lamps will be automatically controlled to maintain a pre-set UV dose based on readings from an in-situ transmittance meter and a signal from the WWTF flow meter. Table 6-6 presents the design criteria for the new UV disinfection system.

TABLE 6-6

UV System Design Criteria

UV Disinfection System Design Maximum Month Flow 0.29 MGDDesign Maximum Day Flow 0.69 MGDDesign Maximum Daily Effluent TSS 30 mg/LDosage Minimum 35 µ Ws/cm2

Effluent Fecal Coliform Limit (Avg. weekly)

200/100 mg/L

Effluent Fecal Coliform Limit (Avg. monthly)

100 per 100 mL

Design UV Transmittance 65%Design Temperature Range 5-28oCUV Lamp Type Low pressure, high intensityBanks 2Channel Length 19 feetChannel Width 22 inchesChannel Depth 18 inchesQuantity of Modules 6Quantity of Lamps/Module 2Total Quantity of Lamps 24

Effluent Pumping



The effluent pumping system for high river flows does not have sufficient capacity for the 20-year planning period. The pumps will be replaced. Table 6-7 presents the design criteria for the effluent pumping system.

TABLE 6-7 Effluent Pumping System Design Criteria

Effluent Pumping System

Quantity 2Type SubmersibleFlow 0.88 MGD or 611 gpmHead 16 feetHorsepower 7.5 hp

Effluent Aeration The NPDES permit requires that this Plan evaluate post aeration to raise the dissolved oxygen level in the effluent. The daily minimum effluent limit for oxygen is 3 mg/L. The DMR data for the last five years indicates that that effluent oxygen was less than 3.0 mg/L six times with the lowest measured level of 2.3 mg/L. The monthly average oxygen effluent limit is 4.0 mg/L which was exceeded four times in the last five years. In addition, 14% of all effluent samples for oxygen were less than 4.0 mg/L. Assuming that the effluent oxygen level is 0 mg/L and that the saturated oxygen level is 10 mg/L with a safety factor of 1.5 for diurnal variations, then the oxygen requirements is 36 lb/day (0.29 MGD x 10 mg/L x 8.345 x 1.5). Oxygenation equipment is specified based upon standard oxygen transfer rate (SOTR), the oxygen transfer rate in clean 20oC water with no suspended solids. The SOTR is calculated as follows:

20

20

024.1

T

S

OSTH

C

CCSOTRAOTR

Where: a = oxygen transfer correction factor, 0.9 (typical for this treatment process)

b = salinity surface tension factor, 0.95 CSTH = dissolved oxygen concentration at operating temperature and elevation, = 8.08 mg/L CS20 = dissolved oxygen concentration at 20oC and 1 atm, 9.08 mg/L CO = operating dissolved oxygen concentration, 2 mg/L T = 25oC (maximum wastewater temperature observed in recent DMRs) The resulting SOTR is therefore 45 lb/d.



The post aeration basin will utilize fine bubble diffusers to transfer oxygen to the effluent. The air will come from the blowers for the aeration basin. Table 6-8 presents the design criteria for the Effluent Aeration.

TABLE 6-8 Effluent Aeration Design Criteria

Effluent Aeration System

Quantity 1Water Depth 8SOTR 45 lb/dayManhole Size 8 ft diameterSide Water Depth 10 ftDiffusers Fine Bubble

Effluent Cooling The NPDES permit requires that this Plan evaluate effluent cooling to lower the effluent temperature. The outfall modeling has determined no violations of the Yakima River temperature criteria are predicted from the discharge during critical conditions. The lower Yakima River water quality temperature standard is 21.0oC. However, the NPDES fact sheet states that 22.78oC is the background water temperature for the lower Yakima River. DMR data for the past five years indicates that only 4% of all effluent temperature measurements were greater than 22.78oC and only 17% greater than 21.0oC. The highest recorded temperature of the wastewater was 29oC and the river standard is 21.0oC. The permit limit will be for daily maximum therefore, the system should be sized for a peak day flow rate of 0.69 MGD. However since 2006, only 4 days had temperatures greater than 27oC and this analysis assumes that maximum day flow and temperatures higher than 27oC will not occur on the same day. The water will be required to be cooled to 21oC or 6oC of cooling required (27oC - 21oC). The following equations sizes the effluent cooling system.

239,840 lb/hour = (0.69 MGD / 1440 min/day) x 60 min/hour * 8.34 lb/gal 10.8oF = 6oC * 1.8oF/ oC 2,590,000 BTU/Hour = 239,840 lb/hour * 10.8oF x 1 BTU/lb –oF 215 tons = 2,590,000 BTU/Hour / 12,000 BTU/hour/Ton A 215 ton chiller is required. Three 72 ton chillers will be provided so that the system will have some redundancy. When wastewater temperatures are closer to the limit only one chiller will operate to save energy costs.



The system will consist of effluent pumps to pump the water to the heat exchanger, a heat exchanger and air cooled chiller. One chiller will operate between 21ºC to 23ºC (13% of the year), two will operate from 23ºC to 25ºC (3% of the year) and all three will operated at greater than 25ºC (1.2% of the year). The capital cost of the system is $730,000 (including contingencies and engineering) and the annual operation and maintenance cost is $16,000 per year. It is not recommended that effluent cooling be installed because outfall modeling has determined no violations of the Yakima River temperature criteria are predicted from the discharge during critical conditions and due to the capital and operation and maintenance cost of the chillers. NONPOTABLE WATER SYSTEM The existing non-potable water system is supplied with water from the City’s water system. Currently the only process that uses water from the non-potable water system is the fine screen. The WWTF needs spray bars at the clarifiers and general wash down water throughout the facility. The spray bars will utilize 20 gpm for each clarifier or approximately 65 acre feet per year. The City’s water system is deficient in water rights and does not have additional water rights to allocate to the WWTF. The construction cost of a nonpotable water system is $42,000 or $650 per acre foot. It typically cost $2,000 to $6,000 per acre foot to purchase water rights. The nonpotable water system is cost effective. The nonpotable water pumps will be submersible pumps located in the effluent pump station. Sodium hypochlorite (12.5% solution) will be utilized for chlorine residual. The chlorine system will be located in the UV building. Table 6-9 presents the design criteria for the nonpotable water system.



TABLE 6-9

Nonpotable Water System Design Criteria

Nonpotable Water System Type SubmersibleQuantity 2Horsepower 5Set point 50 gpm at 80 psiControl Cycle Stop ValveAir Tank 300 galDisinfection Sodium Hypochlorite 12.5%Chlorine Pump Diaphgram Metering Pump No. of Pumps 2

ELECTRICAL SERVICE The plant improvements will add approximately 70 hp of new equipment to the WWTF. Based on the existing metering information for the plant as described previously, the 400 amp existing switchboard appears to have sufficient capacity to serve the new loads. However, the addition of new loads will require upgrades to the motor control centers. The existing motor control centers have spare motor control equipment but will require additional motor control sections for the new aeration basin blowers. Based on the existing metering information for the plant, the existing generator appears to be loaded to approximately 68 percent of its capacity. The current facility plan is to connect one new 25 HP blower, aeration basin, one new 5 HP plant drain lift pump and one new 5 HP recirculation pump to the generator (other additional proposed load additions will be interlocked so that it will not run on the generator). In addition to this, it is possible to interlock an existing 40 HP aerobic tank blower and an existing 5 HP RAS/WAS pump so that they will shed when the generator is running. Based on these revisions, the generator would then be loaded to 95 amps, which would appear to be a load decrease. The problem with this evaluation is that there is no way of knowing whether the existing loads that are noted to be shed were actually in operation when the peak load for the year was recorded by the Utility. If some of these were not in operation, then it would not be prudent to back all of these values out of the calculations. This means that the actual load for the generator could be as high as 150 amps (104 amps peak metered load plus 46 amps of new load). At this loading a new generator will be required.



LAB AND MAINTENANCE BUILDING The lab and maintenance building is functional for the 20-year planning period but it requires a few modifications which will include the following:

Painting HVAC maintenance (replace air conditioner in MCC room) New hot water tank New windows and doors to keep dust out of the lab A laboratory glass washer Equipment for making distilled water Converting the area by the electrical room to office space will add to the area

in the lab. A new backflow prevention device for the building is required to meet current

regulations. SCADA SYSTEM The SCADA system is functional and has the capability to operate for the 20-year planning period but require some modifications to include:

Computer replacement. Upgrade software to current versions. Modifications to the programming to restore functionality presently not

working and to add functions for the new process equipment to be added to the plant.

SOLIDS HANDLING Aerobic Sludge Storage Tank The aerobic sludge storage tank has sufficient capacity for the 20-year planning period. If the tank can maintain a minimum of 20oC then the process can be considered a process to significantly reduce pathogens (PSRP) and will meet the Class B pathogen reduction requirements. It is unlikely that the tank can maintain 20oC during the winter months, therefore the air drying on the sludge drying beds will be utilized to meet the requirement for PSRP. The aerobic sludge storage tank needs modification to include:

Minor maintenance on the blower enclosures to include painting and heater replacement.

Replace the blower VFD. Replace the decant mechanism.



Sludge Drying Beds The sludge drying beds do not have capacity for the 20-year planning period. The City will utilize air drying to meet the standards for vector attraction and Class B pathogen reduction. The vector attraction requirements are as follows:

“Total Solids (TS) is at least 75% when the sewage sludge does not contain unstabilized primary solids and at least 90% when unstabilized primary solids are included. Blending with other materials is not allowed to achieve the total solids percent.”

Because no unstabilized primary solids are generated at the WWTF, air drying to a total solids concentration 75 % should meet this requirement. The Class B pathogen reduction requirements are as follows:

“Sewage sludge is dried on sand beds or on paved or unpaved basins for a minimum of three months. During two of the three months, the ambient average daily temperature is above 0oC.”

As determined in Chapter 5, if the aerobic sludge holding tank can maintain 20oC then Class B pathogen reduction requirements could be meet in the aerobic sludge holding tank. It is unlikely that the aerobic sludge holding tank can maintain 20oC for a large portion of the year therefore air drying will be utilized to meet Class B pathogen reduction requirements. As determined in Chapter 5, the total solids wasted from the aerobic sludge holding tank is 613 lb/day which is 3,672 gpd or 1.34 MG/year for 2% solids content sludge. Three alternatives will be evaluated for solids handling. The three sludge drying beds alternatives will be sized based on the following assumptions and assuming only one year of storage. The three alternatives are as follows:

Paved sludge drying beds without drains – 100 percent of the water will be removed by evaporation. The sludge drying bed area required is 74,050 square feet. This alternative will require the purchase of approximately 3 acres of land.

Paved sludge drying beds with drains – 50 percent of the water will be removed by drains and the remainder by evaporation. The Sludge drying bed area required is 37,000 square feet. This alternative will require the purchase of approximately 1.5 acres of land. This alternative will require a plant drain lift station to return the drain water back to the headworks.

Mechanical dewatering with paved drying beds – The mechanical dewatering will increase the solids content to 15% and the remainder will be removed by evaporation. The sludge drying bed area required is 9,500 square



feet. No additional land is required for this alternative. This alternative will require a plant drain lift station.

Table 6-10 presents the capital cost, operation and maintenance cost and the 20-year present worth cost for each alternative. Capital costs include costs for all improvements at the WWTF. The costs presented are for all improvements as detailed in this chapter. Detail cost estimates are provided in Appendix D.

TABLE 6-10 Cost Comparison Solids Handling

Sludge Drying

Bed No Drains Sludge Drying Bed

With Drains Mechanical Dewatering

Capital Cost (1) $6,033,000 (2) $5,638,000(2) $6,121,000 Annual Operation and Maintenance Cost $270,000 $270,000 $274,000 Present Worth Cost $9,702,000 $9,307,000 $9,845,000 (1) Capital cost includes all improvements required at the WWT. (2) Includes cost of land if required.

The sludge drying bed alternative without drains is not recommended because its capital costs are higher than the cost for beds with drains and more land area is required. The City has decided that the sludge drying beds with drains is the preferred alternative as it is the most cost effective. The City has started the process to purchase at least 4 acres of land. If land purchase is not possible the City will utilize the mechanical dewatering alternative. Table 6-11 presents the design criteria for the sludge drying beds with drains and the mechanical dewatering alternative.



TABLE 6-11

Sludge Handling Design Criteria

Sludge Drying Bed (Sludge Drying Bed Alternative) Type Paved with DrainsArea 57,000 ft^2

Mechanical Dewatering (Mechanical Dewatering Alternative) Type Rotary Screw PressSolids Percentage 15 percentType Paved with DrainsArea 9,500 ft^2

Plant Drain Lift Station (Required both Alternatives) Type SubmersibleNo. of Pumps 2Flow Rate 90 gpm @ 50 Feet of headHorsepower 5 hpWet well diameter 6 ft

Figures 6-8 show the updated hydraulic profile and site plan, respectively. Figure 6-9 shows the sludge drying bed alternative site layout while Figure 6-10 shows the mechanical dewatering alternative. The overall cost for the preferred alternative sludge drying beds with drains is presented in Table 6-10.

CHAPTER 7

WATER RECLAMATION AND REUSE EVALUATION


CHAPTER 7

WATER RECLAMATION AND REUSE EVALUATION As required by RCW 90.48.112, this Plan must evaluate the “opportunities for the use of reclaimed water”. Reclaimed water is defined in RCW 90.46.010 as “effluent derived in any part from sewage from a wastewater treatment system that has been adequately and reliably treated, so that as a result of that treatment, it is suitable for a beneficial use or a controlled use that would not otherwise occur, and is no longer considered wastewater.” Key differences between the requirements for water reuse and those for effluent disposal are the levels of reliability required within the treatment process, distribution, and use areas. The State of Washington’s reuse treatment standards call for continuous compliance, meaning that the treatment standards must be met on a constant basis or the treated water cannot be used as reclaimed water. ALLOWABLE USES FOR RECLAIMED WATER The Washington State Water Reclamation and Reuse Standards describe several allowable uses for reclaimed water, including:

Agricultural irrigation; Landscape irrigation; Impoundments and wetlands; Groundwater recharge; Streamflow augmentation; Industrial and commercial uses; and Municipal uses.

Depending upon its end use, there are four categories of reclaimed water: Class A, Class B, Class C, and Class D. Class A has the highest degree of effluent treatment. In general, when unlimited public access to the reclaimed water is involved or when irrigation of crops for human consumption is the intended end use, the criteria will require Class A reclaimed water. The WWTF currently produces 173 acre feet per year (ac-ft/yr) of effluent and is projected to produce 269 ac-ft/yr in 2031. According to the 2005 Water System Plan, the only large water users in the City are the schools, parks and a nursery which utilizes approximately 196 ac-ft/yr for irrigation. The City could produce Class A reclaimed water to replace the potable water utilized for irrigation. This water reuse evaluation will evaluate the replacement of irrigation at the parks, schools and nursery with Class A reclaimed water.



REUSE EVALUATION Factors that could lead a wastewater treatment provider to pursue reclaimed water include the following:

Cost Effectiveness. The cost to make and reuse reclaimed water is typically higher than the cost to make secondary effluent. In addition, control of the WWTF is more complex at a reclaimed water facility than a typical WWTF.

Regulatory Requirements. Regulatory conditions are such that making reclaimed water is a viable option compared to continuing to discharge secondary effluent.

Water Rights. The ability to make and reuse reclaimed water could benefit the City’s water rights situation.

An evaluation of how each of these factors relates to the City’s WWTF is provided in the following sections.

COST EFFECTIVENESS The following additional improvements will be required at the WWTF to produce Class A reclaimed water. The additional improvements are in addition to the improvements included in Chapter 6.

Polymer addition including coagulation and flocculation tanks Effluent filtration equipment Effluent pump station to pump the effluent to the filtration equipment Building to house the polymer and filtration equipment Additional UV system improvements Lined storage ponds Pump station and pipelines to the irrigation sites Additional land purchase SCADA improvements for additional reliability considerations Bypass valves and piping. This analysis assumes that the reclaimed water

facility will bypass to the Yakima River during periods that the facility does not meet reclaimed water standards

The estimated capital cost for producing reclaimed water is $8,631,000 (see Appendix D for cost estimate) or approximately $50,000 per ac-ft ($8,631,000/ 179 ac-ft first year production). Current purchase price for water rights is approximately $2,000 to $6,000. Therefore, it is not cost effective to produce reclaimed water.


City of Mabton 7-3 Wastewater Facility Plan September-2011

REGULATORY REQUIREMENTS At this time, the City has only had a few violations of its NPDES permit. The improvements listed in Chapter 6 will correct the issues dealing with any permit violations therefore producing reclaimed water is not required to meet the NPDES. The reclaimed water RCW 90.46, states that the City will have exclusive rights to any reclaimed water that it produces and states that the City must compensate or mitigate water rights holders that are impaired by the use of the reclaimed water. The City currently discharges to the Yakima River. The Yakima River is a fully allocated river as determined by the Yakima River adjudication. If the City does not discharge its treatment plant effluent to the river, existing water right holders will likely be impaired. The City believes that the mitigation and compensation costs will be approximately equal to the cost to purchase water rights. If will be less expensive to purchase water rights then to finance the additional improvements to convert the WWTF to a water reclamation facility plus the cost of compensation and mitigation. In addition, the Yakama Nation is on record as opposing any curtailment of discharges to the Yakima River. Current regulatory requirements make it unlikely that the City will receive any benefit from producing reclaimed water.

WATER RIGHTS The City’s water system is currently deficient in water rights for annual quantity. The City could utilize reclaimed water to replace potable water utilized in the City for irrigation thus reducing its need for additional water rights. However as discussed previously, it will be less expensive to purchase water rights than to construct a reclaimed water facility and provide compensation and mitigation.

SUMMARY Evaluation of the potential for water reclamation and reuse indicates that it is not cost effective, that the City would have to compensate and mitigate impaired water right holders, and that it will be less expensive to purchase water rights. Therefore the production of reclaimed water is not recommended.

CHAPTER 8

FINANCING

City of Mabton 8-1 General Sewer Plan and Wastewater Facility Plan September 2011

CHAPTER 8

FINANCING INTRODUCTION This chapter presents a plan for financing the capital improvements recommended in Chapter 6. This chapter includes a review of the City’s current financial status, available revenue sources, allocation of revenues, and the impact of the recommended capital improvement plan on sewer rates. EXISTING SERVICE RATES AND CONNECTION CHARGES The City collects revenue through connection charges and service rates that are established by Mabton Municipal Code. The City has two classifications of customers; residential and commercial. Nurseries are high water using customers, but the water used does not go to the sewer system, therefore nurseries are considered residential customers. Table 8-1 presents the sewer service rates for the City. The City raised its rates by $3.00 per month in November of 2010 and again in 2011 in anticipation of a large capital improvement project increasing revenues for the WWTF improvements.

TABLE 8-1 Sewer Service Base Rates

Classification Base Rate Volume Charge

Residential $37.06 0 Commercial (1) $4.28 per 1,000 gals

(1) Minimum charge of $34.06 per month. HISTORICAL OPERATIONS Sewer utility revenues, expenditures, and the resulting effects on cash and investments for the years 2008-2010 are summarized in Table 8-2. The revenues have exceeded expenses every year since 2009 after the sewer system debt was paid off in 2008. The sewer utility has no debt and a cash balance of $183,000. The water and sewer systems have a Water and Sewer Equipment Fund with a cash balance of $71,000 and a Water and Sewer Emergency Fund with a cash balance of $104,000.


8-2 City of Mabton September 2011 General Sewer Plan and Wastewater Facility Plan

TABLE 8-2 Historical Revenues and Expenditures

Beginning Cash & Investments 2008 2009 2010 Beginning Cash And Investments $122,174 (1) $90,509 $141,839

Revenues 2008 2009 2010 Sewer Sales $232,807 $238,897 $227,869 On/Off Charges (2) $1,180 $2,080 $2,090 Interest (2) $2,647 $700 $270 Sale of Surplus Equipment (2) $216 $175 $0 Sewer Connections $3,000 $3,000 $2,500

Total Revenue $239,849 $244,853 $232,729 Expenses 2008 2009 2010

Sewer Salaries $93,924 $85,812 $54,000 Sewer O/T $5,145 $2,580 $1,201 Sewer Benefits $27,579 $26,069 $9,298 Sewer Operating Supplies $4,599 $6,914 $19,901 Fuel $3,728 $2,727 $2,823 Training $89 $645 $50 Professional Services $1,060 $190 $19,504 Professional Services Wesley $6,265 $1,739 $0 Professional Services Selection Farms $0 $0 $2,685 Professional Services Adelmund $0 $0 $9,000 Communications $3,164 $3,447 $3,788 Travel $10 $0 $237 Sewer Rentals $1,229 $1,018 $703 Insurance $7,815 $8,576 $6,986 Utilities $15,883 $16,199 $23,357 Repairs $24,790 $4,337 $15,434 Miscellaneous $26,138 $24,157 $21,406 Audit Cost $526 $8,667 $0 Copier $439 $446 $484 Backhoe Lease $4,535 $0 $0 Sewer Maintenance $130 $0 $0

Total Expenses $227,048 $193,522 $190,856 Debt Service

US Bank WWTP Principal $43,324 $0 $0 US Bank WWTP Interest $1,142 $0 $0

Total Expenses + Debt Service $271,514 $193,522 $190,856 Net revenues -$31,665 $71,330 $41,873

Ending Balance $90,509 $141,839 $183,712



(1) Beginning Cash & Investment for 2008 equals one-half of the beginning cash & investments for the water and sewer fund.

(2) The miscellaneous revenue for on/off charges, interest and sale of surplus equipment equals one-half of the total for the water and sewer fund.

In early 2010, The City had 566 sewer connections. The monthly base sewer rate for most of 2010 was $31.06 (this rate has since been increased to $37.06 per month). Commercial connections are charged at a higher rate based on the volume charge. The City has 611 financial equivalent residential units based on 2010 sewer sales ($227,869 / 12 months / $31.06 per month 2010 base rate).

CAPITAL IMPROVEMENT PROGRAM Chapter 6 detailed the following projects:

An Infiltration and Inflow (I&I) Study to assess the condition of the sewer collection system. The I&I study will be financed from the sewer system reserves.

Phase 1 WWTF Improvement Project which consists of upgrading the existing mechanical wastewater treatment facility to reliably meet the NPDES permit.

Future Phase 2 WWTF Improvement which consists of a natural treatment polishing process. The purpose of the natural treatment polishing process is environmental enhancement for fisheries and wildlife, environmental education and economic development. This wetland may also be utilized for future storm water treatment for the City or be constructed for wetland mitigation banking. Funding sources for Phase 2 WWTF Improvement will be further evaluated during the predesign report for Phase 1.

The City is pursuing two alternatives for the Phase 1 WWTF Improvement Project. If the City can purchase additional land, the City will construct the Sludge Drying Bed Alternative. If land purchase is not possible then the Mechanical Dewatering Alternative is the preferred alternative.

The following financing alternatives will be evaluated to determine the range of future rates for the sewer utility for Phase 1 WWTF improvement project.

• Scenario No. 1 = 100% Public Works Trust Fund Loan (PWTF) loan at 0.5% for 30 years. According to PWTF guidelines, the City is a distressed community based on income levels and is eligible for the 30 year loan at reduced payments.

• Scenario No. 2 = 100% State Revolving Fund (SRF) loan from the Department of Ecology with an interest rate at 1.7% for 20 years. The 1.7% interest rate is the current hardship interest rate because the sewer monthly rate will be greater than 2.0% of the median household income

• Scenario No. 3 = $1.0 million Community Development Block Grant (CDBG) with the remaining a PWTF loan at 0.5% for 30 years.



• Scenario No. 4 = 100% Rural Development (RD) loan at 3.5% for 40 years. Table 8-3 presents the capital, and operation and maintenance for the two alternatives. The City preferred alternative is the Sludge Drying Bed with Drains Alternative. The City is investigating the purchase of land to be able to construct this alternative. If land cannot be purchased then the City will construct the Mechanical Dewatering Alternative.

TABLE 8-3 Alternative Cost – Capital and Operation and Maintenance Cost

Sludge Drying Bed With

Drains Alternative Mechanical Dewatering

Alternative Capital Cost $5,683,000 $6,121,000 Operation and Maintenance Cost $270,000 $274,000

Table 8-4 presents the projected rates for the two alternatives. The rate projections include the debt service for the WWTF improvements and operation and maintenance costs as presented in Table 8-3.

TABLE 8-4 Sewer Rate Projection for the WWTF Improvements (1)

Sludge Drying Bed With

Drains Alternative

Mechanical Dewatering Alternative

Scenario No. 1 $76 $71 Scenario No. 2 $80 $86 Scenario No. 3 $61 $66 Scenario No. 4 $72 $78 Range $61-80 $66-86 (1) Includes debt service for the WWTF improvements and the operation and maintenance cost as

presented in Table 8-3. Table 8-5 is a schedule for funding program applications for the WWTF improvements. The following sections describe each program.

TABLE 8-5 Funding Program Application Submittal Schedules

Funding Program Application Submittal

Department of Ecology SRF/CCWF November 2011CDBG Early 2012



The City has received two sources of financing for the Phase 1. The first is a $600,000 legislative grant from the State of Washington. The City has also been placed on the offer list for a PWTF loan which will finance the remaining portion of the project. The City intends to apply for the Department of Ecology SRF/CCWF programs in the fall in case the state defunds the PWTF loan during the next legislative session. In addition the City will apply for the CDBG grant program to try to lower the sewer rates. FINANCING OPTIONS PUBLIC WORKS TRUST FUND The Public Works Trust Fund (PWTF) is a revolving loan fund designed to help local governments finance needed public works projects through low-interest loans and technical assistance. The PWTF, established in 1985 by legislative action, offers loans up to $10,000,000 at interest rates substantially below market, payable over periods ranging up to 30 years. Interest rates are 0.5 percent, 1 percent, or 2 percent, with the lower interest rates providing an incentive for a higher local financial share. The local community must provide a minimum of 5 percent of project costs to qualify for a 2 percent loan. A 10 percent local share qualifies the applicant for a 1 percent interest rate and a 15 percent share qualifies for a 0.5 percent loan. Local matches can come from other financing sources. The City of Mabton is considered a distressed community according to PWTF guidelines and is eligible for a 30 year loan at 0.5% with no match required. To be eligible, an applicant must be a local government such as a City, Town, County, or special purpose utility district, and have a long-term plan for financing its public works needs. If the applicant is a Town, City, or County, it must adopt the ¼ percent real estate excise tax dedicated to capital purposes. Eligible public works systems include streets and roads, bridges, storm sewers, sanitary sewers, and domestic water. Loans are offered for purposes of repair, replacement, rehabilitation, reconstruction, or improvement of existing service users. Since 1999, eligible projects may be designed to accommodate reasonable growth. This is generally the 20-year growth projection included in the local government’s comprehensive plan under the Growth Management Act (GMA). USDA RURAL DEVELOPMENT USDA Rural Development (RD) has a loan program that, under certain conditions, includes a limited grant program. Grant determination is based on a formula that incorporates existing utility debt service and existing utility service rates. In addition, USDA RD has a loan program for needy communities that cannot obtain funding by commercial means through the sale of revenue bonds. The loan program



provides long-term 30- to 40-year loans at an interest rate that is based on federal rates and varies with the commercial market. STATE REVOLVING FUND/ CENTENNIAL CLEAN WATER FUND In 1986 the Washington State Legislature established the Centennial Clean Water Fund (CCWF) and State Revolving Fund (SRF). The Department of Ecology is managing a portion of these funds and ensures that the funds are distributed fairly between the best projects and that those projects address the state’s highest priority water pollution control problems. The Legislature directed that the CCWF and SRF be used to finance the planning, design, acquisition, construction, and improvement of water pollution control facilities and activities. The primary program requirements are to have an approved facilities plan for treatment works and to demonstrate the ability to repay loans through a dedicated funding source. Ecology evaluates projects based on the severity of the existing water quality condition or the potential threat to the water quality of a specific body of water, the means of assuring that the project will achieve its intended purpose, and the water quality benefit that would result from the project. Ecology also considers public health emergencies. If the Washington State Department of Health declares a public health emergency, consideration is given to whether the proposed project will directly address and correct that emergency. Emergency funding may be applied for throughout the year. Grant money is available only to those who can document hardship. Financial hardship is demonstrated if the proposed project will result in a user charge in excess of two percent of the median household income. Table 8-6 summarizes the qualifications for financial hardship per the most recent funding cycle.

TABLE 8-6 Ecology Grant/Loan Hardship Funding

Sewer User Fee Divided

By MHI

Below 2.0% 2.0% and above, but

below 3.0%

3.0% and above but

below 5.0%

5.0% and above

Hardship Designation

Non-Hardship Moderate Hardship

Elevated Hardship

Severe Hardship

Grant Hardship Funding

Continuum

0% Grant 50% Grant (up to $5 million)

75% Grant (up to $5 million)

100% Grant (up to $5 million)

Loan Hardship Funding

Continuum(1)

Loan at 60% of market rate

Loan at 40% of market rate

Loan at 20% market rate

Loan at 0% interest



(1) This is the percent of the average market rate for tax exempt municipal bonds. At a median household income of $34,978, the City would have to have a rate of approximately $58.30 per month in order to qualify for any of Ecology’s hardship funding. STATE AND TRIBAL ASSISTANCE GRANTS State and Tribal Assistance Grants (STAG) are available through the U.S. EPA. This funding is part of EPA’s overall appropriations that include the state revolving fund program (which in Washington State is distributed through Ecology’s State Revolving Fund), tribal funding programs, and other EPA funding programs. Money is appropriated on a case-by-case basis, and usually requires that the municipality request intercession from its federal congressional legislators on behalf of its project. At this time, there is no formal application process. Funding is approved as a separate appropriation in EPA’s annual budget. COMMUNITY ECONOMIC REVITALIZATION BOARD This low interest loan and grant program is sponsored by the Department of Trade and Economic Development. Funding is available for infrastructure that supports projects that will result in specific private developments or expansions in manufacturing, and businesses that support the trading of goods and services outside the state border. Funding is not available to support retail shopping developments or acquisition of real property. The projects must create or retain jobs. The average is one job per $3,000 of Community Economic Revitalization Board (CERB) financing. The interest rate fluctuates with the state bond rate. It is unlikely that the capital projects outlined in this plan would qualify for CERB funding. UTILITY LOCAL IMPROVEMENT DISTRICTS Another potential source of funds for capital projects can be obtained through the formation of Utility Local Improvement Districts (ULIDs) involving a special assessment made against properties benefiting by the project. ULID bonds are further backed by a legal claim to the revenues generated by the utility. Sewer system expansion is a frequent application of ULID financing. Typically, ULIDs are formed by the jurisdiction at the written request (by petition) of the property owners within a specific section of the service area. Upon receipt of a sufficient number of signatures or petitions, and acceptance by the council, the local improvement area is formed. Therefore, a sewer system is designed for that particular area in accordance with a sewer comprehensive plan. Each separate property in the ULID is assessed in accordance with the special benefits the property receives from the water or wastewater system improvements. An area-wide ULID could form part of a financing package for large-scale capital projects such as sewer line extensions or replacements that benefit all



residents within the service area. The assessment places a lien on the property that must be paid in full upon sale of the property. ULID participants have the option of paying their assessment immediately upon receipt, thereby reducing the portion of the costs financed by the ULID bonds. The advantages of ULID financing, as opposed to rate financing, to the property owner include:

The ability to avoid interest costs by early payment of assessments. If the ULID assessment is paid in installments, it may be eligible to be

deducted from federal income taxes.

Low-income senior citizens may be able to defer assessment payments until the property is sold.

Some Community Block Grant funds are available to property owners

with incomes near or below poverty level. The major disadvantage to the ULID process is that it may be politically difficult to approve formation. The ULID process may be stopped if 40 percent of the property owners protest its formation. Also, there are significant legal and administrative costs associated with the ULID process, which increases total project costs by approximately 30 percent over other financing options. GENERAL OBLIGATION BONDS The City, by special election, may issue general obligation bonds to finance almost any project of general benefit to the City. Assessments levied against all privately owned properties within the City will pay for the bonds. This includes vacant property that otherwise would not contribute to the cost of such general improvements. This type of bond issue is usually reserved for municipal improvements that are of general benefit to the public, such as arterial streets, bridges, lighting, municipal buildings, firefighting equipment, parks, and water and wastewater facilities. Because the money is raised by assessment levied on property values, the business community also provides a fair share of funds to pay off such bonds. General obligation bonds have the best market value and carry the lowest interest rate of all type of bonds available to the City. Disadvantages of general obligation bonds include the following:

Voter approval is required which may be time-consuming, with no guarantee of successful approval of the bond.



The City would have a practical or legal limit for the total amount of general obligation debt. Financing large capital improvements through general obligation debt reduces the ability of the utility to issue future debt for projects such as parks and community facilities that cannot be directly funded through enterprise funds.

APPENDIX

APPENDIX A

NPDES PERMITS

of 29 Permit No.: WA-002064-8 Issuance Date: March 19, 2007 Effective Date: May 1, 2007 Expiration Date: April 30, 2012

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM WASTE DISCHARGE PERMIT NO. WA-002064-8

STATE OF WASHINGTON

DEPARTMENT OF ECOLOGY YAKIMA, WASHINGTON 98902

In compliance with the provisions of

The State of Washington Water Pollution Control Law Chapter 90.48 Revised Code of Washington

and The Federal Water Pollution Control Act

(The Clean Water Act) Title 33 United States Code, Section 1251 et seq.

CITY OF MABTON

PUBLICLY-OWNED TREATMENT WORKS 305 MAIN STREET

PO BOX 655 MABTON, WA 98935

Plant Location: 900 Vance Road Mabton, WA 98935

Receiving Water: Yakima River, River Mile 59.7

Water Body I.D. No.: WA-37-1010

Discharge Location: Latitude: 46° 14' 04" N Longitude: 119° 59' 18" W

Plant Type: Class II: Anoxic selector, activated sludge, aeration basin, secondary clarification, and UV disinfection. is authorized to discharge in accordance with the special and general conditions that follow.

________________________________ Denise E. Mills, LHG Section Manager Water Quality Program Central Region Office Washington State Department of Ecology

of 29 Permit No.: WA-002064-8 Expiration Date: April 30, 2012

TABLE OF CONTENTS Page

SUMMARY OF PERMIT REPORT SUBMITTALS.................................................................... 4

SPECIAL CONDITIONS............................................................................................................... 5 S1. DISCHARGE LIMITATIONS ...................................................................................... 5

A. Effluent Limitations ....................................................................................................... 5 B. Mixing Zone Descriptions ............................................................................................. 6

S2. MONITORING REQUIREMENTS .............................................................................. 7 A. Monitoring Schedule...................................................................................................... 7 B. Sampling and Analytical Procedures ............................................................................. 8 C. Flow Measurement......................................................................................................... 8 D. Laboratory Accreditation ............................................................................................... 9

S3. REPORTING AND RECORDING REQUIREMENTS ............................................... 9 A. Reporting........................................................................................................................ 9 B. Records Retention ........................................................................................................ 10 C. Recording of Results .................................................................................................... 10 D. Additional Monitoring by the Permittee ...................................................................... 10 E. Twenty-four Hour Notice of Noncompliance Reporting............................................. 10 F. Other Noncompliance Reporting ................................................................................. 11 G. Maintaining a Copy of This Permit.............................................................................. 11

S4. FACILITY LOADING ................................................................................................ 12 A. Design Criteria ............................................................................................................. 12 B. Plan for Maintaining Adequate Capacity..................................................................... 12 C. Duty to Mitigate ........................................................................................................... 13 D. Notification of New or Altered Sources....................................................................... 13 E. Infiltration and Inflow Evaluation................................................................................ 14 F. Waste Load Assessment............................................................................................... 14

S5. OPERATION AND MAINTENANCE ....................................................................... 14 A. Certified Operator ........................................................................................................ 14 B. O & M Program ........................................................................................................... 15 C. Short-term Reduction................................................................................................... 15 D. Electrical Power Failure............................................................................................... 15 E. Prevent Connection of Inflow ...................................................................................... 15 F. Bypass Procedures ....................................................................................................... 15 G. Operations and Maintenance Manual........................................................................... 17

S6. PRETREATMENT ...................................................................................................... 18 A. General Requirements.................................................................................................. 18 B. Wastewater Discharge Permit Required ...................................................................... 18 C. Identification and Reporting of Existing, New, and Proposed Industrial Users .......... 18 D. Duty to Enforce Discharge Prohibitions ...................................................................... 18

S7. RESIDUAL SOLIDS................................................................................................... 20


S8. APPLICATION FOR PERMIT RENEWAL .............................................................. 20 S9. RECEIVING WATER STUDY................................................................................... 20

GENERAL CONDITIONS .......................................................................................................... 22 G1. SIGNATURE AUTHORIZATION/DELEGATION................................................... 22 G2. RIGHT OF INSPECTION AND ENTRY ................................................................... 23 G3. PERMIT ACTIONS..................................................................................................... 23 G4. REPORTING PLANNED CHANGES........................................................................ 24 G5. PLAN REVIEW REQUIRED ..................................................................................... 25 G6. COMPLIANCE WITH OTHER LAWS AND STATUTES....................................... 25 G7. TRANSFER OF THIS PERMIT.................................................................................. 25 G8. REDUCED PRODUCTION FOR COMPLIANCE .................................................... 26 G9. REMOVED SUBSTANCES ....................................................................................... 26 G10. DUTY TO PROVIDE INFORMATION..................................................................... 26 G11. OTHER REQUIREMENTS OF 40 CFR..................................................................... 26 G12. ADDITIONAL MONITORING .................................................................................. 26 G13. PAYMENT OF FEES.................................................................................................. 27 G14. PENALTIES FOR VIOLATING PERMIT CONDITIONS........................................ 27 G15. UPSET ......................................................................................................................... 27 G16. PROPERTY RIGHTS.................................................................................................. 28 G17. DUTY TO COMPLY................................................................................................... 28 G18. TOXIC POLLUTANTS............................................................................................... 28 G19. PENALTIES FOR TAMPERING ............................................................................... 28 G20. REPORTING ANTICIPATED NON-COMPLIANCE............................................... 28 G21. REPORTING OTHER INFORMATION.................................................................... 29 G22. COMPLIANCE SCHEDULES.................................................................................... 29


SUMMARY OF PERMIT REPORT SUBMITTALS Refer to the Special and General Conditions of this permit for additional submittal requirements.

Permit Section

Submittal

Frequency

First Submittal Date

S3. Discharge Monitoring Report Monthly June 15, 2007 S3.E. Noncompliance Notification As necessary S4.B. Plan for Maintaining Adequate Capacity 1/permit cycle June 1, 2009 S4.D. Notification of New or Altered Sources As necessary S4.E. Infiltration and Inflow Evaluation 1/permit cycle June 1, 2008 S4.F. Waste Load Assessment 1/permit cycle December 1, 2008 S5.G. Operations and Maintenance Manual

Update As necessary

S8. Application for permit renewal 1/permit cycle April 30, 2011 S9.B. Receiving Water and Effluent Study

Sampling and Quality Assurance Plan 1/permit cycle June 1, 2008

S9. Receiving Water and Effluent Study Results

2/permit cycle December 30, 2009 and

December 30, 2010 G1. Signature Authorization/Delegation as necessary G4. Reporting Planned Changes As necessary G5. Engineering Report for Construction or

Modification Activities As necessary

G21. Reporting Anticipated Non-compliance As necessary G22. Reporting Other Information As necessary


SPECIAL CONDITIONS

S1. DISCHARGE LIMITATIONS A. Effluent Limitations

All discharges and activities authorized by this permit shall be consistent with the terms and conditions of this permit. The discharge of any of the following pollutants more frequently than, or at a level in excess of, that identified and authorized by this permit shall constitute a violation of the terms and conditions of this permit. Beginning on May 1, 2007 and lasting through April 30, 2012 the permittee is authorized to discharge municipal wastewater at the permitted location subject to compliance with the following limits:

OUTFALL # 1 EFFLUENT LIMITATIONSa Parameter Average Monthly Average Weekly

Biochemical Oxygen Demand (5 day)

10 mg/L, 15.8 lbs/day 85% removal of influent BOD

15 mg/L, 23.6 lbs/day

Total Suspended Solids 30 mg/L, 48 lbs/day 85% removal of influent TSS

45 mg/L, 71 lbs/day

Fecal Coliform Bacteria 100 colonies /100 mL 200 colonies /100 mL

pHb Daily minimum is equal to or greater than 6 and the daily

maximum is less than or equal to 9.

Parameter Average Monthly Maximum Dailyc

Dissolved Oxygen 4 mg/L (minimum) 3 mg/L (minimum)

Total Ammonia (as NH3-N) 20 mg/L 34.6 mg/L a The average monthly and weekly effluent limitations are based on the arithmetic mean of the samples taken with the exception of fecal coliform, which is based on the geometric mean. b Indicates the range of permitted values. The instantaneous maximum and minimum pH shall be reported monthly. c The maximum daily effluent limitation is defined as the highest (or lowest) allowable daily discharge. The daily discharge means the discharge of a pollutant measured during a calendar day. For pollutants with limitations expressed in units of mass, the daily discharge is calculated as the total mass of the pollutant discharged over the day. For other units of measurement, the daily discharge is the average measurement of the pollutant over the day.


B. Mixing Zone Descriptions A mixing zone is not allowed for any parameter listed as impaired on the Ecology 303(d) list in the vicinity of the Mabton POTW outfall. The maximum boundaries of the mixing zones for other parameters are defined as follows: Chronic Mixing Zone The chronic mixing zone is based on the RIVPLUME5 model. The boundaries of the dilution zone are 300 feet long by 31 feet wide downstream and 100 feet upstream. The dilution factor is one to 122.13. Acute Mixing Zone The acute mixing zone is based on the volume fraction equation from WAC 173-201-100(8), which is based on 2.5% of the lowest 7-day average river flow with a recurrence of 10 years. The allowable volume fraction is one to 20.16.


S2. MONITORING REQUIREMENTS

A. Monitoring Schedule

The Permittee shall monitor in accordance with the following schedule:

Category

Parameter

Units

Sample Point

Minimum Sampling Frequency

Sample

Type Wastewater Influenta

Flow

MGD

Parshall flumeb

Continuousc

Metered

“

BOD5

mg/L

“

2/weekd

24-hour compositee

“ TSS mg/L “ 2/week Calculationf

“ Fats, Oil, and Grease

mg/L

“

1/month

Grabg

Wastewater Effluent

BOD5

mg/L

Final effluenth

2/week

24-hour composite

“ BOD5 lbs/day “ 2/week Calculation “ BOD5 % Removali “ 1/month Calculation “

TSS

mg/L

“

2/week

24-hour composite

“ TSS lbs/day “ 2/week Calculation “ TSS % removal “ 1/month Calculation “ Phosphorus

(Total) mg/L P

“

1/month

Grab

“ Fats, Oil, and Grease

mg/L “ 1/month Grab

“ Ph Standard Units “ 5/weekj Grab “ Temperature °C “ 5/week Grab “ Dissolved

Oxygen mg/L “ 5/week Grab

“ Fecal Coliform Bacteria

Colonies/100 mL

“ 2/Week Grab

“ Total ammonia mg/L “ 2/month Grab “ Total ammonia lbs/day “ 2/month Calculation

Sludge As specified in section S7.

Receiving Water

As specified in section S9.


Category

Parameter

Units

Sample Point

Minimum Sampling Frequency

Sample

Type Reapplication Monitoring

Total Hardness

mg/L as CaCO3

Final effluent

1/year

Grab

“ Alkalinity mg/L as

CaCO3

“

1/year

Grab

a. Wastewater Influent means the raw sewage flow and shall be sampled at the headworks of the treatment plant excluding any side-stream returns from inside the plant.

b. Influent will be sampled at the influent sampler located by the Parshall flume. c. Continuous means uninterrupted except for brief lengths of time for calibration, for power failure, or for

unanticipated equipment repair or maintenance. Sampling shall be taken six times per day when continuous monitoring is not possible.

d. "2/week" means 2 times during each calendar week and on a rotational basis throughout all possible days of the week, except weekends and holidays.

e. 24-hour composite means a series of individual samples collected over a 24-hour period into a single container, and analyzed as one sample.

f. "Calculation" means figured concurrently with the respective sample, using the following formula: Concentration (in mg/L) X Flow (in MGD) X Conversion Factor (8.34) = lbs/day.

g. “Grab" means an individual sample collected over a 15 minute, or less, period. h. "Final Effluent" means wastewater which is exiting, or has exited, the last treatment process or operation. i. Percent (%) removal of BOD and TSS shall be calculated with the following algorithm (concentrations in mg/L):

(Average Monthly Influent Concentration - Average Monthly Effluent Concentration)/Average Monthly Influent Concentration.

j. "5/week" means 5 times during each calendar week throughout all possible days of the week, except weekends and holidays.

B. Sampling and Analytical Procedures Samples and measurements taken to meet the requirements of this permit shall be representative of the volume and nature of the monitored parameters, including representative sampling of any unusual discharge or discharge condition, including bypasses, upsets and maintenance-related conditions affecting effluent quality. Sampling and analytical methods used to meet the monitoring requirements specified in this permit shall conform to the latest revision of the Guidelines Establishing Test Procedures for the Analysis of Pollutants contained in 40 CFR Part 136.

C. Flow Measurement

Appropriate flow measurement devices and methods consistent with accepted scientific practices shall be selected and used to ensure the accuracy and reliability of measurements of the quantity of monitored flows. The devices shall be installed, calibrated, and maintained to ensure that the accuracy of the measurements is consistent


with the accepted industry standard for that type of device. Frequency of calibration shall be in conformance with manufacturer's recommendations and at a minimum frequency of at least one calibration per year. Calibration records shall be maintained for at least three years.

D. Laboratory Accreditation

All monitoring data required by the Department shall be prepared by a laboratory registered or accredited under the provisions of, Accreditation of Environmental Laboratories, Chapter 173-50 WAC. Flow, temperature, settleable solids, conductivity, pH, and internal process control parameters are exempt from this requirement. Conductivity and pH shall be accredited if the laboratory must otherwise be registered or accredited. The department exempts crops, soils, and hazardous waste data from this requirement pending accreditation of laboratories for analysis of these media.

S3. REPORTING AND RECORDING REQUIREMENTS The Permittee shall monitor and report in accordance with the following conditions. The falsification of information submitted to the department shall constitute a violation of the terms and conditions of this permit.

A. Reporting

The first monitoring period begins on May 1, 2007. Monitoring results shall be submitted monthly. Monitoring data obtained during each monitoring period shall be summarized, reported, and submitted on a Discharge Monitoring Report (DMR) form provided, or otherwise approved, by the department. DMR forms shall be postmarked or received by the department no later than the 15th day of the month following the completed monitoring period, unless otherwise specified in this permit. The report(s) shall be sent to:

Permit Data Systems Manager Department of Ecology Central Regional Office

15 West Yakima Avenue, Suite 200 Yakima, Washington 98902

All laboratory reports providing data for organic and metal parameters shall include the following information: sampling date, sample location, date of analysis, parameter name, CAS number, analytical method/ number, method detection limit (MDL), laboratory practical quantitation limit (PQL), reporting units, and concentration detected. Analytical results from samples sent to a contract laboratory must have


information on the chain of custody, the analytical method, QA/QC results, and documentation of accreditation for the parameter. Discharge Monitoring Report forms must be submitted monthly whether or not the facility was discharging. If there was no discharge during a given monitoring period, submit the form as required with the words "no discharge" entered in place of the monitoring results.

B. Records Retention

The permittee shall retain records of all monitoring information for a minimum of three years. Such information shall include all calibration and maintenance records and all original recordings for continuous monitoring instrumentation, copies of all reports required by this permit, and records of all data used to complete the application for this permit. This period of retention shall be extended during the course of any unresolved litigation regarding the discharge of pollutants by the permittee or when requested by the department.

C. Recording of Results For each measurement or sample taken, the Permittee shall record the following information:

1. the date, exact place, method, and time of sampling or measurement; 2. the individual who performed the sampling or measurement; 3. the dates the analyses were performed; 4. the individual who performed the analyses; 5. the analytical techniques or methods used; 6. the results of all analyses.

D. Additional Monitoring by the Permittee

If the permittee monitors any pollutant more frequently than required by this permit using test procedures specified by Condition S2. of this permit, then the results of such monitoring shall be included in the calculation and reporting of the data submitted in the Permittee’s DMR.

E. Twenty-four Hour Notice of Noncompliance Reporting

1. The permittee must report the following occurrences of noncompliance by telephone,

to Ecology at 509/575-2490, within 24 hours from the time the permittee becomes aware of the circumstances:


a. any noncompliance that may endanger health or the environment; b. any unanticipated bypass that exceeds any effluent limitation in the permit (See Part

S5.F., “Bypass Procedures”); c. any upset that exceeds any effluent limitation in the permit (See G15., “Upset”); d. any violation of a maximum daily or instantaneous maximum discharge limitation

for any of the pollutants in S1.A.; or e. any overflow prior to the treatment works, whether or not such overflow endangers

health or the environment or exceeds any effluent limitation in the permit.

2. The permittee must also provide a written submission within five days of the time that the permittee becomes aware of any event required to be reported under subpart 1, above. The written submission must contain: a. a description of the noncompliance and its cause; b. the period of noncompliance, including exact dates and times; c. the estimated time noncompliance is expected to continue if it has not been

corrected; d. steps taken or planned to reduce, eliminate, and prevent recurrence of the

noncompliance; and e. if the non compliance involves an overflow prior to the treatment works, an estimate

of the quantity (in gallons) of untreated overflow.

3. Ecology may waive the written report on a case-by-case basis if the oral report has been received within 24 hours of the noncompliance.

4. Reports must be submitted to the address in S3.A “REPORTING AND

RECORDKEEPING REQUIREMENTS”.

F. Other Noncompliance Reporting

The permittee must report all instances of noncompliance, not required to be reported within 24 hours, at the time that monitoring reports for S3.A. "Reporting" are submitted. The reports must contain the information listed in paragraph E above, “Twenty-four Hour Notice of Noncompliance Reporting”. Compliance with these requirements does not relieve the permittee from responsibility to maintain continuous compliance with the terms and conditions of this permit or the resulting liability for failure to comply.

G. Maintaining a Copy of This Permit

A copy of this permit must be kept at the facility and be made available upon request to Department of Ecology inspectors.


S4. FACILITY LOADING A. Design Criteria

Flows or waste loadings of the following design criteria for the permitted treatment facility shall not be exceeded:

• Average flow for the maximum month: 0.189 MGD • Average annual flow: 0.166 MGD • BOD5 loading for maximum month: 478 lb/day • TSS loading for maximum month: 453 lb/day

B. Plan for Maintaining Adequate Capacity

The permittee shall submit to the department for approval a plan and a schedule for continuing to maintain capacity by June 1, 2009.

The plan and schedule for continuing to maintain capacity must be sufficient to achieve the effluent limitations and other conditions of this permit. The plan must identify any of the following actions or any other actions necessary to meet the objective of maintaining capacity.

1. Analysis of the present design including the introduction of any process

modifications that would establish the ability of the existing facility to achieve the effluent limits and other requirements of this permit at specific levels in excess of the existing design criteria specified in Paragraph A, Design Criteria, above.

2. Reduction or elimination of excessive infiltration and inflow of uncontaminated

ground and surface water into the sewer system. 3. Limitation on future sewer extensions or connections or additional waste loads. 4. Modification or expansion of facilities necessary to accommodate increased flow or

waste load. 5. Reduction of industrial or commercial flows or waste loads to allow for increasing

sanitary flow or waste load. The plan for the Mabton POTW must also include the following:

• Identify and evaluate methods and equipment necessary to increase dissolved oxygen in the effluent.


• Identify methods and equipment required to reduce temperature in the effluent. Engineering documents associated with the plan must meet the requirements of WAC 173-240-060, "Engineering Report," and be approved by the department prior to any construction. If the permittee intends to apply for State or Federal funding for the design or construction of a facility project, the plan must also meet the requirements of a “Facility Plan” as described in 40 CFR 35.2030. The plan shall specify any contracts, ordinances, methods for financing, or other arrangements necessary to achieve this objective.

C. Duty to Mitigate

The permittee is required to take all reasonable steps to minimize or prevent any discharge or sludge use or disposal in violation of this permit that has a reasonable likelihood of adversely affecting human health or the environment.

D. Notification of New or Altered Sources

The permittee shall submit written notice to the department whenever any new discharge or a substantial change in volume or character of an existing discharge into the POTW is proposed which:

• would interfere with the operation of, or exceed the design capacity of, any portion of the POTW;

• is not part of an approved general sewer plan or approved plans and specifications; or,

• would be subject to pretreatment standards under 40 CFR Part 403 and Section 307(b) of the Clean Water Act.

This notice shall include an evaluation of the POTW's ability to adequately transport and treat the added flow or waste load, the quality and volume of effluent to be discharged to the POTW, and the anticipated impact on the Permittee’s effluent [40 CFR 122.42(b)].


E. Infiltration and Inflow Evaluation 1. The permittee shall conduct an infiltration and inflow evaluation. Refer to the U.S.

EPA publication, I/I Analysis and Project Certification, available as Publication No. 97-03 at: Publications Office, Department of Ecology, PO Box 47600, Olympia, WA, 98504-7600. Plant monitoring records may be used to assess measurable inflow.

2. A report shall be prepared which summarizes any measurable inflow or infiltration.

If inflow or infiltration is determined to be excessive in accordance with EPA guidance, the report shall contain a plan and a schedule for: (1) locating the sources; and (2) correcting the problem. The report shall be submitted to the department by June 1, 2008.

F. Waste Load Assessment

The permittee shall conduct an assessment of its flow and waste load and submit a report to the department by December 1, 2008. The report shall contain the following: an indication of compliance or noncompliance with the permit effluent limitations; a comparison between the existing and design monthly average dry weather and wet weather flows, peak flows, BOD, and total suspended solids loadings. The report shall also state the present and design population or population equivalent, and projected population growth rate.

S5. OPERATION AND MAINTENANCE

The permittee shall at all times properly operate and maintain all facilities and systems of treatment and control (and related appurtenances) which are installed to achieve compliance with the terms and conditions of this permit. Proper operation and maintenance also includes adequate laboratory controls and appropriate quality assurance procedures. This provision requires the operation of back-up or auxiliary facilities or similar systems, which are installed by a permittee only when the operation is necessary to achieve compliance with the conditions of this permit.

A. Certified Operator

An operator certified for at least a Class II plant by the state of Washington shall be in responsible charge of the day-to-day operation of the wastewater treatment plant. An operator certified for at least a Class I plant shall be in charge during all regularly scheduled shifts.


B. O & M Program The permittee shall institute an adequate operation and maintenance program for the entire sewage system. Maintenance records shall be maintained on all major electrical and mechanical components of the treatment plant, as well as the sewage system and pumping stations. Such records shall clearly specify the frequency and type of maintenance recommended by the manufacturer and shall show the frequency and type of maintenance performed. These maintenance records shall be available for inspection at all times.

C. Short-term Reduction

If a permittee contemplates a reduction in the level of treatment that would cause a violation of permit discharge limitations on a short-term basis for any reason, and such reduction cannot be avoided, the permittee shall give written notification to the department, if possible, 30 days prior to such activities, detailing the reasons for, length of time of, and the potential effects of the reduced level of treatment. This notification does not relieve the permittee of its obligations under this permit.

D. Electrical Power Failure

The permittee is responsible for maintaining adequate safeguards to prevent the discharge of untreated wastes or wastes not treated in accordance with the requirements of this permit during electrical power failure at the treatment plant and/or sewage lift stations either by means of alternate power sources, standby generator, or retention of inadequately treated wastes. The permittee shall maintain Reliability Class II (EPA 430/9-74-001) at the wastewater treatment plant, which requires a backup power source sufficient to operate all vital components and critical lighting and ventilation during peak wastewater flow conditions, except vital components used to support the secondary processes (i.e., mechanical aerators or aeration basin air compressors) need not be operable to full levels of treatment, but shall be sufficient to maintain the biota.

E. Prevent Connection of Inflow

The permittee shall strictly enforce its sewer ordinances and not allow the connection of inflow (roof drains, foundation drains, etc.) to the sanitary sewer system.

F. Bypass Procedures

Bypass, which is the intentional diversion of waste streams from any portion of a treatment facility, is prohibited, and the department may take enforcement action


against a permittee for bypass unless one of the following circumstances (1, 2, or 3) is applicable. 1. Bypass for essential maintenance without the potential to cause violation of permit

limits or conditions. Bypass is authorized if it is for essential maintenance and does not have the potential to cause violations of limitations or other conditions of this permit, or adversely impact public health as determined by the department prior to the bypass. The permittee shall submit prior notice, if possible at least 10 days before the date of the bypass.

2. Bypass which is unavoidable, unanticipated and results in noncompliance of this permit.

This bypass is permitted only if: a. Bypass is unavoidable to prevent loss of life, personal injury, or severe

property damage. “Severe property damage” means substantial physical damage to property, damage to the treatment facilities which would cause them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass.

b. There are no feasible alternatives to the bypass, such as the use of auxiliary

treatment facilities, retention of untreated wastes, stopping production, maintenance during normal periods of equipment downtime (but not if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventative maintenance), or transport of untreated wastes to another treatment facility.

c. The department is properly notified of the bypass as required in condition S3.E

of this permit.

3. Bypass which is anticipated and has the potential to result in noncompliance of this permit. The Permittee shall notify the department at least 30 days before the planned date of bypass. The notice shall contain: (1) a description of the bypass and its cause; (2) an analysis of all known alternatives which would eliminate, reduce, or mitigate the need for bypassing; (3) a cost-effectiveness analysis of alternatives including comparative resource damage assessment; (4) the minimum and maximum duration of bypass under each alternative; (5) a recommendation as to the preferred


alternative for conducting the bypass; (6) the projected date of bypass initiation; (7) a statement of compliance with SEPA; (8) a request for modification of water quality standards as provided for in WAC 173-201A-110, if an exceedance of any water quality standard is anticipated; and (9) steps taken or planned to reduce, eliminate, and prevent reoccurrence of the bypass. For probable construction bypasses, the need to bypass is to be identified as early in the planning process as possible. The analysis required above shall be considered during preparation of the engineering report or facilities plan and plans and specifications and shall be included to the extent practical. In cases where the probable need to bypass is determined early, continued analysis is necessary up to and including the construction period in an effort to minimize or eliminate the bypass. The department will consider the following prior to issuing an administrative order for this type bypass: a. If the bypass is necessary to perform construction or maintenance-related

activities essential to meet the requirements of this permit. b. If there are feasible alternatives to bypass, such as the use of auxiliary treatment

facilities, retention of untreated wastes, stopping production, maintenance during normal periods of equipment down time, or transport of untreated wastes to another treatment facility.

c. If the bypass is planned and scheduled to minimize adverse effects on the public

and the environment. After consideration of the above and the adverse effects of the proposed bypass and any other relevant factors, the department will approve or deny the request. The public shall be notified and given an opportunity to comment on bypass incidents of significant duration, to the extent feasible. Approval of a request to bypass will be by administrative order issued by the department under RCW 90.48.120.

G. Operations and Maintenance Manual

The approved Operations and Maintenance Manual shall be kept available at the treatment plant and all operators shall follow the instructions and procedures of this manual. The O&M Manual shall be reviewed by the permittee at least annually. Substantial changes or updates to the O&M Manual shall be incorporated into the manual and submitted to the department for review and approval.


S6. PRETREATMENT A. General Requirements

The permittee shall work with the department to ensure that all commercial and industrial users of the publicly owned treatment works (POTW) are in compliance with the pretreatment regulations promulgated in 40 CFR Part 403 and any additional regulations that may be promulgated under Section 307(b) (pretreatment) and 308 (reporting) of the Federal Clean Water Act.

B. Wastewater Discharge Permit Required

The permittee shall not allow significant industrial users (SIUs) to discharge wastewater to the Permittee's sewerage system until such user has received a wastewater discharge permit from the department in accordance with Chapter 90.48 RCW and Chapter 173-216 WAC, as amended.

C. Identification and Reporting of Existing, New, and Proposed Industrial Users

1. The permittee shall take continuous, routine measures to identify all existing, new,

and proposed SIUs and potential significant industrial users (PSIUs) discharging or proposing to discharge to the Permittee's sewerage system (see Appendix B of Fact Sheet for definitions).

2. Within 30 days of becoming aware of an unpermitted existing, new, or proposed

industrial user who may be an SIU, the permittee shall notify such user by registered mail that, if classified as an SIU, they shall be required to apply to the Department and obtain a State Waste Discharge Permit. A copy of this notification letter shall also be sent to the department within this same 30-day period.

3. The permittee shall also notify all PSIUs, as they are identified, that if their

classification should change to an SIU, they shall be required to apply to the department for a State Waste Discharge Permit within 30 days of such change.

D. Duty to Enforce Discharge Prohibitions

1. In accordance with 40 CFR 403.5(a), the permittee shall not authorize or

knowingly allow the discharge of any pollutants into its POTW which cause pass through or interference, or which otherwise violates general or specific discharge prohibitions contained in 40 CFR Part 403.5 or WAC-173-216-060.


2. The permittee shall not authorize or knowingly allow the introduction of any of the following into its treatment works: a. Pollutants which create a fire or explosion hazard in the POTW (including, but

not limited to waste streams with a closed cup flashpoint of less than 140 degrees Fahrenheit or 60 degrees Centigrade using the test methods specified in 40 CFR 261.21).

b. Pollutants which will cause corrosive structural damage to the POTW, but in

no case discharges with pH lower than 5.0, or greater than 11.0 standard units, unless the works are specifically designed to accommodate such discharges.

c. Solid or viscous pollutants in amounts that could cause obstruction to the flow

in sewers or otherwise interfere with the operation of the POTW. d. Any pollutant, including oxygen demanding pollutants, (BOD, etc.) released in

a discharge at a flow rate and/or pollutant concentration which will cause interference with the POTW.

e. Petroleum oil, nonbiodegradable cutting oil, or products of mineral origin in

amounts that will cause interference or pass through. f. Pollutants which result in the presence of toxic gases, vapors, or fumes within

the POTW in a quantity which may cause acute worker health and safety problems.

g. Heat in amounts that will inhibit biological activity in the POTW resulting in

interference but in no case heat in such quantities such that the temperature at the POTW headworks exceeds 400C (1040F) unless the department, upon request of the permittee, approves, in writing, alternate temperature limits.

h. Any trucked or hauled pollutants, except at discharge points designated by the

permittee. i. Wastewaters prohibited to be discharged to the POTW by the Dangerous

Waste Regulations (Chapter 173-303 WAC), unless authorized under the Domestic Sewage Exclusion (WAC 173-303-071).

3. The following are prohibited from discharge to the POTW unless approved in

writing by the department under extraordinary circumstances (such as a lack of direct discharge alternatives due to combined sewer service or the need to augment sewage flows due to septic conditions):


a. Noncontact cooling water in significant volumes. b. Stormwater and other direct inflow sources. c. Wastewaters significantly affecting system hydraulic loading, which do not

require treatment, or would not be afforded a significant treatment. 4. The permittee shall notify the department if any industrial user violates the

prohibitions listed in this section.

S7. RESIDUAL SOLIDS

Residual solids include screenings, grit, scum, primary sludge, waste activated sludge, and other solid waste. The permittee shall store and handle all residual solids in such a manner so as to prevent their entry into state ground or surface waters. The permittee shall not discharge leachate from residual solids to state surface or ground waters.

S8. APPLICATION FOR PERMIT RENEWAL The permittee shall submit an application for renewal of this permit by April 30, 2011.

S9. RECEIVING WATER STUDY

A. The permittee must collect receiving water information necessary to determine if the

effluent has a reasonable potential to cause a violation of the water quality standards. If reasonable potential exists, Ecology will use this information to calculate effluent limits.

B. The permittee must submit a sampling and quality assurance plan for Ecology review and approval by June 1, 2008. The plan must include the following requirements:

1. The permittee must sample and analyze the receiving water for fecal coliform bacteria, hardness, alkalinity, temperature, pH, dissolved oxygen, ammonia, and total phosphorus.

2. Receiving water sampling will occur two times per month during the critical period (July, August, and September) during 2009 and 2010.

3. Record the sampling station location with an accuracy of ± 65 feet.

4. The receiving water sampling location should be at least 100 feet upstream and outside the zone of influence of the effluent.


5. The Permittee must conduct all sampling and analysis in accordance with the guidelines given in Guidelines for Preparing Quality Assurance Project Plans for Environmental Studies, Ecology Publication 04-03-030 (http://www.ecy.wa.gov/pubs/0403030.pdf).

6. Any subsequent sampling and analysis must also meet these requirements.

7. The Permittee may conduct a cooperative receiving water study with other NPDES permittees discharging in the same vicinity.

8. The permittee must submit the results of the study to Ecology on or before December 30, 2009 and December 30, 2010.


GENERAL CONDITIONS G1. SIGNATURE AUTHORIZATION/DELEGATION

All applications, reports, or information submitted to the Department shall be signed and certified. A. All permit applications shall be signed by either a principal executive officer or a

ranking elected official. B. All reports required by this permit and other information requested by the Department

shall be signed by a person described above or by a duly authorized representative of that person. A person is a duly authorized representative only if: 1. The authorization is made in writing by a person described above and submitted to

the Department. 2. The authorization specifies either an individual or a position having responsibility

for the overall operation of the regulated facility, such as the position of plant manager, superintendent, position of equivalent responsibility, or an individual or position having overall responsibility for environmental matters. (A duly authorized representative may thus be either a named individual or any individual occupying a named position.)

C. Changes to authorization. If an authorization under paragraph B.2 above is no longer

accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization satisfying the requirements of paragraph B.2 above must be submitted to the Department prior to or together with any reports, information, or applications to be signed by an authorized representative.

D. Certification. Any person signing a document under this section shall make the

following certification: I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false


information, including the possibility of fine and imprisonment for knowing violations.

G2. RIGHT OF INSPECTION AND ENTRY

The permittee shall allow an authorized representative of the department, upon the presentation of credentials and such other documents as may be required by law: A. To enter upon the premises where a discharge is located or where any records must be

kept under the terms and conditions of this permit. B. To have access to and copy - at reasonable times and at reasonable cost - any records

required to be kept under the terms and conditions of this permit. C. To inspect - at reasonable times - any facilities, equipment (including monitoring and

control equipment), practices, methods, or operations regulated or required under this permit.

D. To sample or monitor - at reasonable times - any substances or parameters at any

location for purposes of assuring permit compliance or as otherwise authorized by the Clean Water Act.

G3. PERMIT ACTIONS

This permit may be modified, revoked and reissued, or terminated either at the request of any interested person (including the permittee) or upon the department’s initiative. However, the permit may only be modified, revoked and reissued, or terminated for the reasons specified in 40 CFR 122.62, 122.64 or WAC 173-220-150 according to the procedures of 40 CFR 124.5. A. The following are causes for terminating this permit during its term, or for denying a

permit renewal application:

1. Violation of any permit term or condition. 2. Obtaining a permit by misrepresentation or failure to disclose all relevant facts. 3. A material change in quantity or type of waste disposal. 4. A determination that the permitted activity endangers human health or the

environment, or contributes to water quality standards violations and can only be regulated to acceptable levels by permit modification or termination [40 CFR part 122.64(3)].

5. A change in any condition that requires either a temporary or permanent reduction, or elimination of any discharge or sludge use or disposal practice controlled by the permit [40 CFR part 122.64(4)].


6. Nonpayment of fees assessed pursuant to RCW 90.48.465. 7. Failure or refusal of the Permittee to allow entry as required in RCW 90.48.090.

B. The following are causes for modification but not revocation and reissuance except

when the permittee requests or agrees:

1. A material change in the condition of the waters of the state. 2. New information not available at the time of permit issuance that would have

justified the application of different permit conditions. 3. Material and substantial alterations or additions to the permitted facility or

activities which occurred after this permit issuance. 4. Promulgation of new or amended standards or regulations having a direct

bearing upon permit conditions, or requiring permit revision. 5. The permittee has requested a modification based on other rationale meeting the

criteria of 40 CFR Part 122.62. 6. The department has determined that good cause exists for modification of a

compliance schedule, and the modification will not violate statutory deadlines. 7. Incorporation of an approved local pretreatment program into a municipality’s

permit.

C. The following are causes for modification or alternatively revocation and reissuance:

1. Cause exists for termination for reasons listed in A1 through A7 of this section, and the department determines that modification or revocation and reissuance is appropriate.

2. The department has received notification of a proposed transfer of the permit. A permit may also be modified to reflect a transfer after the effective date of an automatic transfer (General Condition G8. but will not be revoked and reissued after the effective date of the transfer except upon the request of the new permittee.

G4. REPORTING PLANNED CHANGES

The permittee shall, as soon as possible, but no later than 60 days prior to the proposed changes, give notice to the department of planned physical alterations or additions to the permitted facility, production increases, or process modification which will result in:

1. the permitted facility being determined to be a new source pursuant to 40 CFR

122.29(b) 2. a significant change in the nature or an increase in quantity of pollutants discharged 3. a significant change in the POTW’s sludge use or disposal practices.


Following such notice, and the submittal of a new application or supplement to the existing application, along with required engineering plans and reports, this permit may be modified, or revoked and reissued pursuant to 40 CFR 122.62(a) to specify and limit any pollutants not previously limited. Until such modification is effective, any new or increased discharge in excess of permit limits or not specifically authorized by this permit constitutes a violation of the terms and conditions of this permit.

G5. PLAN REVIEW REQUIRED

Prior to constructing or modifying any wastewater control facilities, an engineering report and detailed plans and specifications shall be submitted to the department for approval in accordance with Chapter 173-240 WAC. Engineering reports, plans, and specifications shall be submitted at least 180 days prior to the planned start of construction unless a shorter time is approved by Ecology. Facilities shall be constructed and operated in accordance with the approved plans.

G6. COMPLIANCE WITH OTHER LAWS AND STATUTES Nothing in this permit shall be construed as excusing the permittee from compliance with any applicable federal, state, or local statutes, ordinances, or regulations.

G7. TRANSFER OF THIS PERMIT

In the event of any change in control or ownership of facilities from which the authorized discharge emanate, the permittee shall notify the succeeding owner or controller of the existence of this permit by letter, a copy of which shall be forwarded to the department. A. Transfers by Modification

Except as provided in paragraph B (Automatic Transfers) below, this permit may be transferred by the permittee to a new owner or operator only if this permit has been modified or revoked and reissued under 40 CFR 122.62(b)(2), or a minor modification made under 40 CFR 122.63(d), to identify the new permittee and incorporate such other requirements as may be necessary under the Clean Water Act.

B. Automatic Transfers

This permit may be automatically transferred to a new permittee if: 1. The permittee notifies the department at least 30 days in advance of the proposed

transfer date.


2. The notice includes a written agreement between the existing and new permittees containing a specific date transfer of permit responsibility, coverage, and liability between them.

3. The department does not notify the existing permittee and the proposed new permittee of its intent to modify or revoke and reissue this permit. A modification under this subparagraph may also be minor modification under 40 CFR 122.63. If this notice is not received, the transfer is effective on the date specified in the written agreement.

G8. REDUCED PRODUCTION FOR COMPLIANCE

The permittee, in order to maintain compliance with its permit, shall control production and all discharges upon reduction, loss, failure, or bypass of the treatment facility until the facility is restored or an alternative method of treatment is provided. This requirement applies in the situation where, among other things, the primary source of power of the treatment facility is reduced, lost, or fails.

G9. REMOVED SUBSTANCES

Collected screenings, grit, solids, sludges, filter backwash, or other pollutants removed in the course of treatment or control of wastewaters shall not be resuspended or reintroduced to the final effluent stream for discharge to state waters.

G10. DUTY TO PROVIDE INFORMATION

The permittee shall submit to the department, within a reasonable time, all information which the department may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit or to determine compliance with this permit. The permittee shall also submit to the department upon request, copies of records required to be kept by this permit.

G11. OTHER REQUIREMENTS OF 40 CFR

All other requirements of 40 CFR 122.41 and 122.42 are incorporated in this permit by reference.

G12. ADDITIONAL MONITORING

The department may establish specific monitoring requirements in addition to those contained in this permit by administrative order or permit modification.


G13. PAYMENT OF FEES

The permittee shall submit payment of fees associated with this permit as assessed by the Department.

G14. PENALTIES FOR VIOLATING PERMIT CONDITIONS

Any person who is found guilty of willfully violating the terms and conditions of this permit shall be deemed guilty of a crime, and upon conviction thereof shall be punished by a fine of up to $10,000 and costs of prosecution, or by imprisonment in the discretion of the court. Each day upon which a willful violation occurs may be deemed a separate and additional violation.

Any person who violates the terms and conditions of a waste discharge permit shall incur, in addition to any other penalty as provided by law, a civil penalty in the amount of up to $10,000 for every such violation. Each and every such violation shall be a separate and distinct offense, and in case of a continuing violation, every day's continuance shall be deemed to be a separate and distinct violation.

G15. UPSET

Definition – “Upset” means an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.

An upset constitutes an affirmative defense to an action brought for noncompliance with such technology-based permit effluent limitations if the requirements of the following paragraph are met.

A permittee who wishes to establish the affirmative defense of upset shall demonstrate, through properly signed, contemporaneous operating logs, or other relevant evidence that: 1) an upset occurred and that the permittee can identify the cause(s) of the upset; 2) the permitted facility was being properly operated at the time of the upset; 3) the permittee submitted notice of the upset as required in condition S3.E.; and 4) the permittee complied with any remedial measures required under S4.C. of this permit.

In any enforcement proceeding, the permittee seeking to establish the occurrence of an upset has the burden of proof.


G16. PROPERTY RIGHTS

This permit does not convey any property rights of any sort, or any exclusive privilege.

G17. DUTY TO COMPLY

The permittee shall comply with all conditions of this permit. Any permit noncompliance constitutes a violation of the Clean Water Act and is grounds for enforcement action; for permit termination, revocation and reissuance, or modification; or denial of a permit renewal application.

G18. TOXIC POLLUTANTS

The permittee shall comply with effluent standards or prohibitions established under Section 307(a) of the Clean Water Act for toxic pollutants within the time provided in the regulations that establish those standards or prohibitions, even if this permit has not yet been modified to incorporate the requirement.

G19. PENALTIES FOR TAMPERING

The Clean Water Act provides that any person who falsifies, tampers with, or knowingly renders inaccurate any monitoring device or method required to be maintained under this permit shall, upon conviction, be punished by a fine of not more than $10,000 per violation, or by imprisonment for not more than two years per violation, or by both. If a conviction of a person is for a violation committed after a first conviction of such person under this Condition, punishment shall be a fine of not more than $20,000 per day of violation, or by imprisonment of not more than 4 years, or by both.

G20. REPORTING ANTICIPATED NON-COMPLIANCE

The permittee shall give advance notice to the department by submission of a new application or supplement thereto at least 180 days prior to commencement of such discharges, of any facility expansions, production increases, or other planned changes, such as process modifications, in the permitted facility or activity which may result in noncompliance with permit limits or conditions. Any maintenance of facilities, which might necessitate unavoidable interruption of operation and degradation of effluent quality, shall be scheduled during noncritical water quality periods and carried out in a manner approved by the Department.


G21. REPORTING OTHER INFORMATION

Where the permittee becomes aware that it failed to submit any relevant facts in a permit application, or submitted incorrect information in a permit application, or in any report to the department, it shall promptly submit such facts or information.

G22. COMPLIANCE SCHEDULES

Reports of compliance or noncompliance with, or any progress reports on, interim and final requirements contained in any compliance schedule of this permit shall be submitted no later than 14 days following each schedule date.

FACT SHEET FOR NPDES PERMIT NO. WA-002064-8

CITY OF MABTON

PUBLICLY-OWNED TREATMENT WORKS

DATE OF THIS FACT SHEET – MARCH 5, 2007 DATE OF EXPIRING PERMIT - APRIL 30, 2012

SUMMARY

The city of Mabton owns and operates an activated sludge treatment plant which discharges treated effluent to the Yakima River. A major plant upgrade was completed in 1999. Due to funding and space limitations, the upgrade was designed with less than optimal sludge handling and hydraulic capacity. This permit will require a Plan to Maintain Adequate Capacity. The lower Yakima River in the vicinity of the Mabton POTW outfall has been listed on the Department of Ecology’s 303(d) list of impaired water bodies because of violations of temperature, fecal coliform, dissolved oxygen, and pesticide concentrations. Recently, phosphorus has been measured at concentrations of concern in the lower Yakima River. Watershed studies may be performed in the future to control the sources of these pollutants. Analysis for fats, oil and grease in the wastewater has not yet been performed, but fats in the influent wastewater have been observed to be a problem for the proper functioning of the treatment plant headworks and clarifiers. This permit will require analysis for fats, oils and grease. Testing for phosphorus will also be required. The Yakima River in the vicinity of the Mabton POTW outfall is deep and slow moving. During the critical period, the low velocity that occurs in this portion of the river results in increased temperature and reduced dissolved oxygen. Effluent limits for biochemical oxygen demand have been reduced and the minimum dissolved oxygen concentrations have been increased to levels that the treatment plant has routinely achieved. Identification of methods to lower temperature and increase dissolved oxygen in the effluent will be required by this permit. Additional characterization of the receiving water will be required prior to submittal of the next application for permit renewal.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 2 of 51 EXPIRATION DATE: APRIL 30, 2012

TABLE OF CONTENTS Page

SUMMARY.................................................................................................................................... 1

INTRODUCTION .......................................................................................................................... 4

GENERAL INFORMATION......................................................................................................... 5

BACKGROUND INFORMATION ............................................................................................... 5 DESCRIPTION OF THE FACILITY ........................................................................................ 5

History ..................................................................................................................................... 5 Collection System Status ......................................................................................................... 6 Treatment Processes ................................................................................................................ 6 Discharge Outfall..................................................................................................................... 7 Residual Solids ........................................................................................................................ 7

PERMIT STATUS...................................................................................................................... 7 SUMMARY OF COMPLIANCE WITH THE PREVIOUS PERMIT ...................................... 8 INFLUENT CHARACTERIZATION ....................................................................................... 9 WASTEWATER CHARACTERIZATION............................................................................... 9

PROPOSED PERMIT LIMITATIONS........................................................................................ 10 DESIGN CRITERIA ................................................................................................................ 11 TECHNOLOGY-BASED EFFLUENT LIMITATIONS......................................................... 12 SURFACE WATER QUALITY-BASED EFFLUENT LIMITATIONS ................................ 12

Numerical Criteria for the Protection of Aquatic Life........................................................... 13 Numerical Criteria for the Protection of Human Health ....................................................... 13 Narrative Criteria ................................................................................................................... 13 Antidegradation ..................................................................................................................... 13 Critical Conditions................................................................................................................. 14 Mixing Zones......................................................................................................................... 14 Description of the Receiving Water ...................................................................................... 17 Surface Water Quality Criteria .............................................................................................. 17

RECEIVING WATER CHARACTERIZATION .................................................................... 18 Consideration of Surface Water Quality-Based Limits for Numeric Criteria ....................... 19 Whole Effluent Toxicity ........................................................................................................ 23

GROUND WATER QUALITY LIMITATIONS..................................................................... 23

MONITORING REQUIREMENTS............................................................................................. 24 LAB ACCREDITATION......................................................................................................... 25 REPORTING AND RECORDKEEPING................................................................................ 25 PREVENTION OF FACILITY OVERLOADING.................................................................. 25 OPERATION AND MAINTENANCE (O&M)....................................................................... 26

Inflow and Infiltration............................................................................................................ 26


RESIDUAL SOLIDS HANDLING.......................................................................................... 27 PRETREATMENT................................................................................................................... 27

Federal and State Pretreatment Program Requirements ........................................................ 27 Wastewater Permit Required ................................................................................................. 28 Requirements for Routine Identification and Reporting of Industrial Users......................... 28 Duty to Enforce Discharge Prohibitions................................................................................ 29 Support by the Department for Developing Partial Pretreatment Program by POTW.......... 29

GENERAL CONDITIONS ...................................................................................................... 29 PERMIT MODIFICATIONS ................................................................................................... 29 RECOMMENDATION FOR PERMIT ISSUANCE............................................................... 30

REFERENCES FOR TEXT AND APPENDICES....................................................................... 31

APPENDIX A--PUBLIC INVOLVEMENT INFORMATION................................................... 33

APPENDIX B--GLOSSARY ....................................................................................................... 34

APPENDIX C -- DATA AND TECHNICAL CALCULATIONS .............................................. 40

APPENDIX D--RESPONSE TO COMMENTS .......................................................................... 51


INTRODUCTION The Federal Clean Water Act (FCWA, 1972, and later modifications in 1977, 1981, and 1987) established water quality goals for the navigable (surface) waters of the United States. One of the mechanisms for achieving the goals of the Clean Water Act is the National Pollutant Discharge Elimination System of permits (NPDES permits), which is administered by the US Environmental Protection Agency (EPA). The EPA has authorized the State of Washington to administer the NPDES permit program. Chapter 90.48 Revised code of Washington (RCW) defines the Department of Ecology's authority and obligations in administering the wastewater discharge permit program. The regulations adopted by the State include procedures for issuing permits [Chapter 173-220 Washington Administrative Code (WAC)], technical criteria for discharges from municipal wastewater treatment facilities (Chapter 173-221 WAC), water quality criteria for surface and ground waters (Chapters 173-201A and 200 WAC), and sediment management standards (Chapter 173-204 WAC). These regulations require that a permit be issued before discharge of wastewater to waters of the state is allowed. The regulations also establish the basis for effluent limitations and other requirements which are to be included in the permit. One of the requirements (WAC 173-220-060) for issuing a permit under the NPDES permit program is the preparation of a draft permit and an accompanying fact sheet. Public notice of the availability of the draft permit is required at least thirty days before the permit is issued (WAC 173-220-050). The fact sheet and draft permit are available for review. (See Appendix A, Public Involvement, of the fact sheet for more detail on the public notice procedures.) The fact sheet and draft permit have been reviewed by the permittee. Errors and omissions identified in this review have been corrected before going to public notice. After the public comment period has closed, the department will summarize the substantive comments and the response to each comment. The summary and response to comments will become part of the file on the permit and parties submitting comments will receive a copy of the department's response. The fact sheet will not be revised. Comments and the resultant changes to the permit will be summarized in Appendix D, Response to Comments.


GENERAL INFORMATION Applicant City of Mabton

Facility Name and Address

City of Mabton Publicly-Owned Treatment Works (POTW) 900 Vance Road Mabton, WA 98935

Type of Treatment: Anoxic selector, activated sludge, aeration basin, secondary clarification, and UV disinfection, aerated sludge digester, and sludge drying beds.

Discharge Location Yakima River, River Mile 59.7 Latitude: 46° 13' 55" N Longitude: 119° 59' 32" W

Water Body ID Number

WA-37-1010

BACKGROUND INFORMATION DESCRIPTION OF THE FACILITY History An oxidation ditch plant was constructed in 1976 on the site of a former 1954 treatment plant. A major upgrade was completed in 1999. The upgrade included the following modifications:

• Headworks improvements, including a new comminutor, a manually-cleaned rock trap, an in-channel fine screen system, a new ultrasonic flow meter to the Parshall flume, and a new composite sampler

• Conversion of the existing tank to new anoxic conditioning tank • New 30 hp aerators to the existing aeration tank • One new secondary clarifier • New sludge pumping facilities Return Activated Sludge (RAS) and Waste Activated

Sludge (WAS) for both secondary clarifiers • Ultraviolet (UV) light disinfection system • Submersible pump station (for effluent pumping at high receiving water levels) • New aerated WAS storage tank with blower


• New sludge drying beds with positive displacement pump for feed • Improvements and updates to onsite laboratory • Installation of Supervisory Control and Data Acquisition (SCADA) computer center • Upgrade of electrical and power system.

Collection System Status The City of Mabton sewer system flows by gravity to a 10-inch main that continues out to the POTW. Additional areas have been identified for expansion of the sewer system, but Mabton is has a low growth rate compared to other areas in the Yakima Valley. The 2003 population estimate was 2045 (Esvelt 2003). The 1993 population estimate was 1660 (Esvelt and Spink 1993), giving a rate of population increase of approximately two percent per year for that period. An infiltration and inflow report was required by the existing permit, but was not prepared. The recent drought period resulted in a decreased flow to the POTW (May 2004 to April 2005) of about 18.6% from the current year (May 2005 to April 2006), and from previous years. This indicates a potential for excessive inflow, infiltration, and exfiltration. Treatment Processes The facility is a Class II plant. It has 2 operators, but only one is certified. The POTW is staffed intermittently from 7:00 a.m. to 6:00 p.m., Monday through Friday. Commercial dischargers include several restaurants. The City's collection system terminates at the bypass box, which normally directs influent to the headworks. For headworks service, the bypass box can divert wastewater to the aeration basin. Wastewater enters the treatment plant at the headworks and receives physical treatment as it passes through a rock trap, a comminutor, and a fine screen system. The rock trap consists of two channels, either of which can accommodate the full design flow capacity. The rock trap is designed to remove large debris to prevent excessive wear and damage to downstream equipment. The headworks includes: a comminutor for solids shredding, designed to process up to 0.45 million gallons per day (MGD). Wastewater is then fine screened to remove debris larger than 0.125 inches. Screenings are captured on the perforated plate and removed by a screw conveyor. After screening, influent flows are measured at the Parshall flume with an ultrasonic level sensor. Influent is sampled at the Parshall flume by a flow-proportional composite sampler. Wastewater from the headworks is mixed with return activated sludge (RAS) from the clarifiers in the conditioning tank. The mixture is then discharged to the aeration basin for further biological treatment. The aeration basin is an oval linear channel measuring 19 feet wide and 5.5 feet deep. The basin is equipped with two 30 hp horizontal surface rotor-type aerators with

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 7 of 51 EXPIRATION DATE: APRIL 30, 2012 variable frequency drives. Control of aerator speeds, which regulates dissolved oxygen (DO) levels within the basin, can be manual or computer operated. The tank is equipped with a DO meter that sends a DO signal to the computer system, which can control aerator speed to maintain a preset DO concentration. The two clarifiers are normally operated in series, but can be operated in parallel. The solids removed from the clarifiers are either utilized as RAS to the aeration basin or designated as WAS and piped to the aerobic digester. Following clarification, wastewater is disinfected in the UV system, which consists of two banks of UV lamps. Waste sludge is pumped from the bottom of the clarifiers to the aerated sludge digester. The sludge flow can be controlled manually or by the computer system. Waste sludge is pumped out of the storage tank to the drying beds, where it is air dried in preparation for land application by Natural Selection Farms. During wet months, sludge is stored in the aerobic digester. Discharge Outfall After UV disinfection, treated effluent is conveyed about 0.4-mile northwest of the treatment plant to a 10-inch diameter outfall pipe. The effluent is discharged into the Yakima River through a single port. A pump station allows the facility to discharge during high flow conditions in the river. At low river flow conditions, the outfall pipe invert is located approximately one foot from shore, at a depth of 1.5 feet (Conley Engineering 2001). The invert is approximately 6 feet above the river bottom elevation (1998 survey), for a total low flow depth of 7.5 feet. Residual Solids The treatment facilities remove solids during the treatment of the wastewater at the headworks (grit and screenings), and at the secondary clarifiers, in addition to incidental solids (rags, scum, and other debris) removed as part of the routine maintenance of the equipment. Grit, rags, scum and screenings are drained and disposed of as solid waste at the local landfill. Sludge is wasted from the clarifiers to the aerated sludge digester tank. The resulting biosolids are land applied at Natural Selection Farms under the General Biosolids Permit. The sludge is pumped to sludge drying beds for air-drying prior to land application. PERMIT STATUS The previous permit for this facility was issued on December 6, 2001. The previous permit placed effluent limitations on 5-day Biochemical Oxygen Demand (BOD5), Total Suspended Solids (TSS), pH, Fecal Coliform Bacteria, Total Residual Chlorine and Dissolved Oxygen.


Table 1. Final effluent limitations from the previous permit EFFLUENT LIMITATIONSa: OUTFALL # 001

Parameter Average Monthly Average Weekly Biochemical Oxygen Demandb (5 day) (BOD5)

30 mg/L, 48 lbs/day 45 mg/L, 71 lbs/day

Total Suspended Solidsb (TSS) 30 mg/L, 48 lbs/day 45 mg/L, 71 lbs/day Fecal Coliform Bacteria 100 colonies/ 100 mL 200 colonies/100 mL pHc Between 6 and 9 at all times. Total Residual Chlorine (TRC) 0.5 mg/L, 0.8 lbs/day 0.75 mg/L, 1.2 lbs/day Parameter Minimum Daily Dissolved Oxygen (DO) 2 mg/L a The average monthly and weekly effluent limitations are based on the arithmetic mean of the samples taken with the exception of fecal coliform, which is based on the geometric mean. b The average monthly effluent concentration for BOD5 and Total Suspended Solids shall not exceed 30 mg/L or 15 percent of the respective monthly average influent concentrations, whichever is more stringent. c The minimum daily effluent limitation is defined as the lowest allowable daily discharge concentration. The daily discharge means the discharge of a pollutant measured during a calendar day. For other units of measurement, the daily discharge is the average measurement of the pollutant over the day.

The facility has UV disinfection. Total Residual Chlorine concentrations in the effluent were consistently below method detection limits. Therefore, the monitoring requirement for chlorine has been omitted from the new permit. An application for permit renewal was submitted to the department on December 30, 2005 and accepted, as complete, by the department on May 25, 2006. SUMMARY OF COMPLIANCE WITH THE PREVIOUS PERMIT The facility was last inspected on June 15, 2006. Over the past 3 years, May 2003 through April 2006, the permit violations have included TSS effluent limitations exceeded or not reported, low DO, and late monthly reports. TSS effluent limits were exceeded in May and September 2003; in January, March, April, October, November, and December 2004; and in January 2005. Monthly minimum DO concentrations were less than the minimum daily permit limit of 2 mg/L eight times between August 2003 and April 2005. During the past year (May 2005 to April 2006), no permit violations have been identified. However, on June 2, 2006 the plant was observed to be in poor condition. The first clarifier sludge blanket exceeded design capacity and was bulking sludge, the adjacent sump was overflowing with foam, and the digester was nearly filled with sludge. Poor general housekeeping was also observed. By the end of August 2006, the problems had been adequately corrected.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 9 of 51 EXPIRATION DATE: APRIL 30, 2012 INFLUENT CHARACTERIZATION Loadings to the POTW were reported in monitoring reports (DMRs) submitted to the Department and are compared with the applicable design criteria as follows:

Table 2: Influent Characterization May 2003 – April 2006 3-year Characterization

Design Criteria

Parameter

3-year Average Highest Monthly

Average Monthly Average for the Maximum Month

BOD5, in lbs/day

362

629

478

TSS, in lbs/day 324

493 453

Flow MGD 0.154 0.208 0.189 Design Criteria are from the June 2000 Operations and Maintenance Manual (Esvelt and Spink 2000). During the past year (May 2005 to April 2006), the average annual flow was equal to the annual average design flow (0.166 MGD). Although testing for fats, oil and grease has not been performed, fats in the influent wastewater have been observed to be a problem for the proper functioning of the treatment plant headworks, including clogging the fine screens. Fats may also be contributing to foam problems in the clarifiers. WASTEWATER CHARACTERIZATION The concentration of pollutants in the discharge was reported in the NPDES application and in discharge monitoring reports. The effluent is characterized as follows:


Table 3: Effluent Characterization May 2003–April 2006 3-year Characterization Existing Permit Limits

Parameter 3-year Average

Highest Monthly Average

Highest Weekly Average

Monthly Average

Weekly Average

BOD5, in mg/L 4.82 9.00 10.04 30 45

TSS, in mg/L 18.53 59.00 108.00 30 45

Fecal Coliform Bacteria, in #colonies/100 mL

28 (7-day GM); 13 (30-day

GM)

48 (30-day GM)

65.5 (7-day GM)

100 200

Ammonia, in mg/L 10.76 36.30 None

Oxygen 4.27 1.60 (Monthly minimum)

2.0 mg/L Daily

minimum

Temperature 16.91 23.83 25.90 (Daily) None

pH standard units 7.5 6 to 9

Alkalinity mg/L 241 350 None

PROPOSED PERMIT LIMITATIONS

Federal and state regulations require that effluent limitations set forth in a NPDES permit must be either technology- or water quality- based. Technology-based limitations for municipal discharges are set by regulations Code of Federal Regulations (CFR) 40 CFR 133, and Chapters 173-220 and 173-221 WAC. Water quality-based limitations are based upon compliance with the Surface Water Quality Standards (Chapter 173-201A WAC), Ground Water Standards (Chapter 173-200 WAC), Sediment Quality Standards (Chapter 173-204 WAC) or the National Toxics Rule (40 CFR 131.36.) The most stringent of these types of limits must be chosen for each of the parameters of concern. Each of these types of limits is described in more detail below.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 11 of 51 EXPIRATION DATE: APRIL 30, 2012 The limits in this permit are based in part on information received in the application. The effluent constituents in the application were evaluated on a technology- and water quality-basis. The limits necessary to meet the rules and regulations of the State of Washington were determined and included in this permit. Ecology does not develop effluent limits for all pollutants that may be reported on the application as present in the effluent. Some pollutants are not treatable at the concentrations reported, are not controllable at the source, are not listed in regulation, and do not have a reasonable potential to cause a water quality violation. Effluent limits are not always developed for pollutants that may be in the discharge but not reported as present in the application. In those circumstances the permit does not authorize discharge of the non-reported pollutants. Effluent discharge conditions may change from the conditions reported in the permit application. If significant changes occur in any constituent, as described in 40 CFR 122.42(a), the permittee is required to notify the Department of Ecology. The permittee may be in violation of the permit until the permit is modified to reflect additional discharge of pollutants. DESIGN CRITERIA In accordance with WAC 173-220-150 (1)(g), flows or waste loadings shall not exceed approved design criteria. The design criteria for this treatment facility are taken from the June 2000 Operations and Maintenance manual and Engineering Report (Esvelt and Spink 2000; 1993) and are as follows:

Table 4: Design Standards for Mabton WWTP Parameter Design Quantity Monthly average flow (max. month) 0.189 MGD Annual average flow 0.166 MGD Instantaneous peak flow 0.500 MGD BOD5 influent loading 478 lb./day TSS influent loading 453 lb./day Nitrogen (TKN) 91 lb./day Ammonia, as Nitrogen 60 lb./day Design population equivalent 2,515

Due to funding and space limitations, the upgrade was designed with less than optimal sludge handling and hydraulic capacity. During the past year, average annual and maximum daily flow, and BOD5 maximum month influent loadings exceeded design standards. A June 30, 2005 draft Plan to Maintain Adequate Capacity was not approved by the department. Permit condition S4. requires the submittal of a Plan to Maintain Adequate Capacity. The plan will include options to reduce effluent temperature and phosphorus, and to increase effluent dissolved oxygen.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 12 of 51 EXPIRATION DATE: APRIL 30, 2012 TECHNOLOGY-BASED EFFLUENT LIMITATIONS Municipal wastewater treatment plants are a category of discharger for which technology-based effluent limits have been promulgated by federal and state regulations. These effluent limitations are given in 40 CFR Part 133 and in Chapter 173-221 WAC. These regulations are performance standards that constitute all known available and reasonable methods of prevention, control, and treatment for municipal wastewater. The following technology-based limits for pH, fecal coliform, BOD5, and TSS are taken from Chapter 173-221 WAC are:

Table 5: Technology-based Limits Parameter Limit pH: Shall be within the range of 6 to 9 standard units.

Fecal Coliform Bacteria Monthly Geometric Mean = 200 organisms/100 mL

Weekly Geometric Mean = 400 organisms/100 mL

BOD5

(concentration) Average Monthly Limit is the most stringent of the following: - 30 mg/L - may not exceed fifteen percent (15%) of the average influent concentration Average Weekly Limit = 45 mg/L

TSS (concentration)

Average Monthly Limit is the most stringent of the following: - 30 mg/L - may not exceed fifteen percent (15%) of the average influent concentration Average Weekly Limit = 45 mg/L

SURFACE WATER QUALITY-BASED EFFLUENT LIMITATIONS In order to protect existing water quality and preserve the designated beneficial uses of Washington's surface waters, WAC 173-201A-060 states that waste discharge permits shall be conditioned such that the discharge will meet established Surface Water Quality Standards. The Washington State Surface Water Quality Standards (Chapter 173-201A WAC) is a state regulation designed to protect the beneficial uses of the surface waters of the state. Water quality-based effluent limitations may be based on an individual waste load allocation (WLA) or on a WLA developed during a basin-wide water cleanup plan or total maximum daily load study. Total maximum daily loads (TMDLs) result from a scientific study of the water body and are developed in order to reduce pollution from all sources.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 13 of 51 EXPIRATION DATE: APRIL 30, 2012 Numerical Criteria for the Protection of Aquatic Life "Numerical" water quality criteria are numerical values set forth in the State of Washington's Water Quality Standards for Surface Waters (Chapter 173-201A WAC). They specify the levels of pollutants allowed in receiving water while remaining protective of aquatic life. Numerical criteria set forth in the Water Quality Standards are used along with chemical and physical data for the wastewater and receiving water to derive the effluent limits in the discharge permit. When surface water quality-based limits are more stringent or potentially more stringent than technology-based limitations, they must be used in a permit. Numerical Criteria for the Protection of Human Health The state was issued 91 numeric water quality criteria for the protection of human health by the US EPA (EPA 1992). These criteria are designed to protect humans from cancer and other disease and are primarily applicable to fish and shellfish consumption and drinking water from surface waters. Narrative Criteria In addition to numerical criteria, "narrative" water quality criteria (WAC 173-201A-030) limit toxic, radioactive, or deleterious material concentrations below those which have the potential to adversely affect characteristic water uses, cause acute or chronic toxicity to biota, impair aesthetic values, or adversely affect human health. Narrative criteria protect the specific beneficial uses of all fresh (WAC 173-201A-130) and marine (WAC 173-201A-140) waters in the State of Washington. Antidegradation The State of Washington's Antidegradation Policy requires that discharges into receiving water shall not further degrade the existing water quality of the water body. In cases where the natural conditions of receiving water are of lower quality than the criteria assigned, the natural conditions shall constitute the water quality criteria. Similarly, when receiving waters are of higher quality than the criteria assigned, the existing water quality shall be protected. More information on the State Antidegradation Policy can be obtained by referring to WAC 173-201A-070 (1998 Rule). Ambient monitoring in the receiving water above the outfall was required by the previous permit. The data were collected during the critical period from July to September during 2005 and 2006. Parameters measured included dissolved oxygen, temperature, pH, fecal coliform, and ammonia. These data were used in modeling the discharge to determine compliance with water quality standards. Parameters that did not meet water quality standards in the receiving water during the critical period included dissolved oxygen, fecal coliform, and temperature.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 14 of 51 EXPIRATION DATE: APRIL 30, 2012 Critical Conditions Surface water quality-based limits are derived for the water body’s critical condition, which represents the receiving water and waste discharge condition with the highest potential for adverse impact on the aquatic biota, human health, and existing or characteristic water body uses. Usable flow data from USGS flow gaging stations in the Yakima River are available both upstream and downstream of Mabton. However, there are two large irrigation canal diversions downstream of the upper station (Nob Hill), and the Ahtanum Creek confluence with the Yakima River. These canals have maximum capacities of 2,000 and 1,300 cubic feet per second (cfs), respectively. The return flows from the diversions enter the river before the next flow station (Kiona). Irrigation canals are not always filled to capacity, but the highest flows occur from approximately June 20 to September 20. The Yakima River is managed intensively for irrigation, flooding, and fish passage and rearing by using storage basins (USDOI Bureau of Reclamation 2002; 2004). Peak river flow occurs from April to June. The target low flows in the Yakima River below the diversions for July to September are 300 to 600 cfs depending on the total water supply available. During a drought year with insufficient storage, 300 cfs would be used between Parker and Prosser (USDOI Bureau of Reclamation 2002). Because of the lack of flow data usable for analysis in the reach of the Yakima River in the vicinity of the Mabton Outfall, 300 cfs flow is used as the 7Q10 low flow (the lowest 7-day average river flow with a recurrence of 10 years). Because of the warm air temperatures and high flow diverted for irrigation, the critical condition for the pollutants in this discharge is July through September. Mixing Zones

This permit authorizes an acute and a chronic mixing zone around the point of discharge as allowed by Chapter 173-201A WAC, Water Quality Standards for Surface Waters of the State of Washington. A mixing zone is not be allowed for fecal coliform bacteria, dissolved oxygen, or any other parameters that may be listed as impaired on the Ecology 303(d) list in the vicinity of the Mabton POTW outfall. The Water Quality Standards stipulate criteria that must be met before a mixing zone is allowed. The requirements and Ecology’s actions are summarized as follows:

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 15 of 51 EXPIRATION DATE: APRIL 30, 2012 1. The allowable size and location be established in a permit.

Volume-fraction and size-limited dilution factors were determined at the lowest 7-day average river flow with a recurrence interval of 10 years (7Q10). These factors were used to determine reasonable potential to exceed water quality standards.

2. Fully apply “all known available and reasonable methods of treatment” (AKART).

The technology-based limitations determined to be AKART are discussed in an earlier Section of this fact sheet.

3. Consider critical discharge condition.

The critical discharge condition is often pollutant-specific or water body-specific and is discussed above.

4. Supporting information clearly indicates the mixing zone would not have a

reasonable potential to cause the loss of sensitive or important habitat, substantially interfere with the existing or characteristic uses, result in damage to the ecosystem or adversely affect public health.

The Department of Ecology has reviewed the information on the characteristics of the discharge, receiving water characteristics and the discharge location. A mixing zone is not authorized for parameters listed on the Ecology 303(d) list as impaired in the vicinity of the Mabton POTW outfall. For other parameters, Ecology believes this discharge does not have a reasonable potential to cause the loss of sensitive or important habitat, substantially interfere with existing or characteristics uses, result in damage to the ecosystem or adversely affect public health.

5. Water quality criteria shall not be violated (exceeded) outside the boundary of a

mixing zone.

A reasonable potential analysis, using procedures established by the Unites States Environmental Protection Agency (EPA) and the Department of Ecology, was conducted for each pollutant to assure there will be no violations of the water quality criteria outside the boundary of a mixing zone. Calculations are included in Appendix C.

6. The size of the mixing zone and the concentrations of the pollutants shall be

minimized.

The size of the mixing zone (in the form of the dilution factor) has been minimized by the use of design criteria with low probability of occurrence. For example, the reasonable potential analysis used the expected 90th percentile pollutant and background


concentrations, the centerline dilution factor, and the 7-day low flow occurring once in every 10 years. The concentrations of the pollutants in the mixing zone have been minimized by requiring pollution prevention measures where applicable.

7. Maximum size of mixing zone

The authorized mixing zone does not exceed the maximum size restriction. 8. Acute Mixing Zone

A. Acute criteria met as near to the point of discharge as practicably attainable

For allowed parameters, the acute criteria have been determined to be met at the volume fraction of the acute mixing zone.

B. Concentration, duration, and frequency of exposure to the discharge, will not

create a barrier to migration or translocation of indigenous organisms to a degree that has the potential to cause damage to the ecosystem.

The toxicity of pollutants is dependent upon the exposure which, in turn, is dependent upon the concentration and the time the organism is exposed to that concentration. For example, EPA gives the acute criteria for copper as “freshwater aquatic organisms and their uses should not be affected unacceptably if the 1-hour average concentration (in µg/l) does not exceed the numerical value given by (0.960)(e(0.9422[ ln(hardness)] - 1.464)) more than once every 3 years on the average.” The limited acute mixing zone authorized for this discharge will assure that it will not create a barrier to migration. The effluent from this discharge will rise as it enters the receiving water assuring that it will not cause translocation of indigenous organism near the point of discharge.

C. Comply with size restrictions

The mixing zone authorized for this discharge meets the size restrictions of WAC 173-201A.

9. Overlap of Mixing Zones

This mixing zone does not overlap another mixing zone.

The National Toxics Rule (EPA, 1992) allows the chronic mixing zone to be used to meet human health criteria.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 17 of 51 EXPIRATION DATE: APRIL 30, 2012 Description of the Receiving Water The lower Yakima River in the vicinity of the Mabton POTW outfall has been listed on the Department’s 303(d) list of impaired water bodies because of violations of temperature, fecal coliform, dissolved oxygen, and pesticide concentrations. TMDLs have been established for the Moxee and Granger Drains, which discharge to the Yakima River above Mabton. Recently, phosphorus has been measured at levels of concern in the lower Yakima. Fifty percent of phosphorus measured in the reach of the lower Yakima River near Zillah (upstream of Mabton) resulted from wastewater treatment plants (Zuroske, personal communication 2006). In the future, lower Yakima River TMDLs may be established for pesticides, fecal coliform bacteria, dissolved oxygen, phosphorus, and temperature. The facility discharges to the Yakima River, which is designated as a Class A (1998 Rule) receiving water in the vicinity of the outfall. The nearest point source outfalls include the City of Granger’s sewage treatment plant outfall, located approximately 15 miles upstream, the City of Grandview treatment plant outfall located 5 miles downstream. Other nearby point source outfalls include City of Sunnyside POTW and the Port of Sunnyside Industrial Wastewater Treatment Facility, which both discharge via an irrigation return drain and the Sulfur Creek Wasteway to the Yakima River about two miles upriver from the Mabton outfall. Significant nearby non-point sources of pollutants include the large Toppenish and Granger irrigation drain systems. Characteristic uses include the following:

Water supply (domestic, industrial, agricultural); stock watering; fish migration; fish and shellfish rearing, spawning and harvesting; wildlife habitat; primary contact recreation; sport fishing; boating and aesthetic enjoyment; commerce and navigation.

Water quality of this class shall meet or exceed the requirements for all or substantially all uses. Surface Water Quality Criteria Applicable criteria are defined in Chapter 173-201A WAC for aquatic biota. In addition, U.S. EPA has promulgated human health criteria for toxic pollutants (EPA 1992). Criteria for this discharge are summarized below:


Table 6. Surface water quality criteria Parameter Criteria

Fecal Coliforms 100 organisms/100 mL maximum geometric mean

Dissolved Oxygen 8 mg/L minimum

Temperature 21 degrees Celsius maximum or incremental increases

above background

pH 6.5 to 8.5 standard units

Turbidity less than 5 NTUs above background

Toxics No toxics in toxic amounts

RECEIVING WATER CHARACTERIZATION The Yakima River in the vicinity of the Mabton POTW outfall is deep and slow moving. About five river miles below Mabton there is a short stretch with better aeration in the vicinity of the Grandview POTW outfall. After that point there are continuous deep pools to Prosser. During the critical period, the low velocity that occurs in this portion of the river results in increased temperature and reduced dissolved oxygen. Dissolved oxygen in the lower Yakima River has been measured at night at concentrations of concern for the survival of aquatic life (Coffin personal communication 2006). Samples were collected in the Yakima River upstream of the outfall July through September in 2005 and 2006. Two samples per month were collected by Mabton POTW staff and analyzed by City of Sunnyside treatment plant lab. The results are included in Appendix C, and are summarized in Table 7 below.


Table 7. Results of receiving water sampling and analysis

Parameter

Average

Maximum

Temperature ºC

21.9

26.5

Fecal coliform, colonies/100ml

102

297

Dissolved Oxygen, mg/L 8.71 7.04 (Minimum)

pH, Standard Units 8.03 8.51

Ammonia, mg/l 0.33 0.82

During the critical period, both average and maximum temperatures exceeded the Yakima River water quality criterion. Dissolved oxygen was measured below the water quality criterion during July and August 2005, a low flow period. Consideration of Surface Water Quality-Based Limits for Numeric Criteria Pollutant concentrations in the proposed discharge exceed water quality criteria with technology-based controls which the Department has determined to be AKART. A mixing zone is authorized in accordance with the geometric configuration, flow restriction, and other restrictions for mixing zones in Chapter 173-201A WAC (1998 Rule). Chronic and Acute Dilution Factors A mixing zone study was prepared which determined dilution factors for the discharge. Dilution factors were calculated utilizing both the volume fraction equation from WAC 173-201A-100(8) and the Department’s standard RivPlume5 model (Fischer et al. 1979). Both analyses are based on the average monthly (chronic) and daily maximum critical period flows (acute). The calculations are included in Appendix C, and the results are summarized in Table 8 below: Table 8. Dilution Factors Calculated by Volume Fraction Equation and RivPlume5 Model

Dilution Factor Volume Fraction Equation RIVPLUME5 Model

Acute 20.16 26.28

Chronic 282.80 122.13 The most protective dilution factors are 20.16 (acute) and 122.13 (chronic). These factors were used to determine the impacts of pH and ammonia in the effluent on receiving water quality.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 20 of 51 EXPIRATION DATE: APRIL 30, 2012 Pollutants in an effluent may affect the aquatic environment near the point of discharge (near field) or at a considerable distance from the point of discharge (far field). Toxic pollutants, for example, are near-field pollutants-their adverse effects diminish rapidly with mixing in the receiving water. Conversely, a pollutant such as BOD is a far-field pollutant whose adverse effect occurs away from the discharge even after dilution has occurred. Thus, the method of calculating water quality-based effluent limits varies with the point at which the pollutant has its maximum effect. The derivation of water-quality-based limits also takes into account the variability of the pollutant concentrations in both the effluent and the receiving water. The critical condition for the Yakima River is the 7-day average low river flow with a recurrence interval of 10 years (7Q10). Ambient data were collected at critical conditions in the vicinity of the Mabton POTW outfall. The data were collected and analyzed by City of Sunnyside POTW personnel during the critical period (July to September) in years 2005 and 2006.

Table 9. Values used in modeling impacts of the discharge on receiving water

Parameter Value Used

7Q10 low flow 300 cfs

Velocity 0.22 ft/sec

Depth 1.5 feet to outfall invert; 7.5 feet total

Width 180 feet

Roughness (Manning’s

N)

n=0.033

Temperature 22.78 ºC

pH (high) 8.26 SU (90th percentile)

Dissolved Oxygen 7.11 mg/L (10th percentile)

Total Ammonia-N 0.57 mg/L (90th percentile)

Fecal Coliform 211 colonies/100 mL dry weather (90th percentile)

BOD5 and Dissolved Oxygen Because this segment of the Yakima River is listed as impaired for dissolved oxygen, a mixing zone is not authorized. However, the impact of low dissolved oxygen in the effluent on the receiving water was modeled using EPA methods and a dilution factor of one. Average effluent

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 21 of 51 EXPIRATION DATE: APRIL 30, 2012 concentration impacts were modeled using the range of dissolved oxygen concentrations measured in the receiving water (7.04 to 10.35 mg/L). At every receiving water concentration measured, the resulting dissolved oxygen concentration at the edge of the mixing zone violated water quality standards (Appendix C). The permittee will be required to identify and evaluate methods to increase dissolved oxygen in the effluent as part of the plan to maintain adequate capacity. Minimum dissolved oxygen limits for this permit will be decreased to 4 mg/L average monthly and 3 mg/L daily. The impact of BOD on the receiving water was modeled using the Streeter-Phelps analysis of critical dissolved oxygen sag (Appendix C). Under critical conditions there were predictions of violations of the dissolved oxygen criterion for receiving water when dissolved oxygen levels in the receiving water were less than 8.10 mg/L. The lower 10th percentile was 7.11 mg/L and the average during the critical period (July to September) was 8.71 mg/L. A monthly average BOD5 effluent limit of 10 mg/L could not be shown to be protective of the dissolved oxygen criterion through use of the Streeter-Phelps model, but is a lower limit that the plant can achieve. The maximum monthly average for the past three years (May 2003 to April 2006) was 9 mg/L. Therefore, 10 mg/L average monthly maximum will be imposed instead of the technology-based limitation. The following water quality-based mass limits will be used for BOD5 in the permit.

• Monthly effluent mass loadings (lbs/day) were calculated as the maximum monthly design flow (0.189 MGD) x concentration limit (10 mg/L) x 8.34 (conversion factor) = mass limit 15.8 lbs/day.

• The maximum weekly average effluent mass loading is calculated as 1.5 x monthly

loading = 23.6 lbs/day.

Temperature The lower Yakima River temperature water quality standard is 21.0 oC. Average and maximum daily temperatures measured upstream of the outfall during the critical period were greater than 21.0 oC. When natural temperatures exceed 21.0oC, temperature increases that raise the temperature by greater than 0.3 oC are not allowed. When natural temperatures do not exceed 21

oC, the allowed increase due to the addition of the effluent is limited to )9/(34 += Tt , where t is the maximum permissible temperature increase and T is the ambient temperature. A flow-weighted average was calculated to determine the potential to exceed the water quality standards for temperature (Appendix C). No violations of the temperature criteria are predicted from the discharge during critical conditions, based on maximum monthly effluent flow, the 7Q10 low river flow, and the upper 90 percentile river and effluent temperatures.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 22 of 51 EXPIRATION DATE: APRIL 30, 2012 During the critical period, temperatures measured upstream of the outfall exceeded water quality criteria in the lower Yakima River. The river segment that the Mabton POTW discharges to is listed as impaired for temperature. Because of the need to reduce temperatures from all sources, a future Yakima River basin temperature TMDL study may determine a temperature waste load allocation (WLA) for the Mabton POTW for protection of water quality in the Yakima River. The Permittee will be required to include options to lower the effluent temperature in its Plan to Maintain Adequate Capacity (Permit Condition S4.). pH The impact of pH was modeled with temperature effects using the calculations from EPA (1988) (Appendix C). The input variables were dilution factors, upstream temperature, pH, and alkalinity (as mg CaCO3/L), effluent temperature, effluent pH, and effluent alkalinity (as mg CaCO3/L). Under critical conditions there is no predicted violation of the Water Quality Standards for Surface Waters. Therefore, the technology-based effluent limits for pH were placed in the permit. Fecal Coliform A mixing zone cannot be authorized for fecal coliform because the lower Yakima River is listed as impaired for fecal coliform under critical conditions. Because there is no mixing zone allowed for the discharge, the technology-based limit would result in violations of the fecal coliform criterion for the receiving water. An effluent limit equal to the water quality criteria (100 colonies/100 ml) was imposed instead of the technology-based limitation. Toxic Pollutants Federal regulations (40 CFR 122.44) require NPDES permits to contain effluent limits for toxic chemicals in an effluent whenever there is a reasonable potential for those chemicals to exceed the surface water quality criteria. This process occurs concurrently with the derivation of technology-based effluent limits. Facilities with technology-based effluent limits defined in regulation are not exempted from meeting the Water Quality Standards for Surface Waters or from having surface water quality-based effluent limits. Ammonia was determined to be present in the discharge. A reasonable potential analysis (see Appendix C) was conducted to determine whether or not effluent limitations would be required in this permit.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 23 of 51 EXPIRATION DATE: APRIL 30, 2012 The determination of the reasonable potential for ammonia to exceed the water quality criteria was evaluated with procedures given in EPA (1991) (Appendix C) at the critical condition. The critical condition in this case occurs July to September. The parameters used in the critical condition modeling are acute and chronic dilution factors, the estimated ambient average ammonia concentration, the upper 90th percentile effluent concentration, and the upper 90th percentile receiving water temperature. Ambient background data were available for ammonia, but most measurements were below accurate quantitation. Because of this, the average value was used instead of the upper 90th percentile. Effluent limits were derived for ammonia, which was determined to have a reasonable potential to cause a violation of the Water Quality Standards. Effluent limits were calculated using methods from EPA (1991) as shown in Appendix C. The resultant ammonia effluent limits are 20.0 mg/L average monthly and 34.6 mg/L maximum daily. Whole Effluent Toxicity The Water Quality Standards for Surface Waters require that the effluent not cause toxic effects in the receiving waters. Many toxic pollutants cannot be detected by commonly available detection methods. However, toxicity can be measured directly by exposing living organisms to the wastewater in laboratory tests and measuring the response of the organisms. Toxicity tests measure the aggregate toxicity of the whole effluent, and therefore this approach is called whole effluent toxicity (WET) testing. Toxicity caused by unidentified pollutants is not expected in the effluent from this discharge as determined by the screening criteria given in Chapter 173-205 WAC. Therefore, no whole effluent toxicity testing is required in this permit. The Department may require effluent toxicity testing in the future if it receives information that toxicity may be present in this effluent. GROUND WATER QUALITY LIMITATIONS The Department has promulgated Ground Water Quality Standards (Chapter 173-200 WAC) to protect uses of ground water. Permits issued by the Department shall be conditioned in such a manner so as not to allow violations of those standards (WAC 173-200-100). This Permittee has no discharge to ground and therefore no limitations are required based on potential effects to ground water.


Table 10. Comparison Of Proposed Effluent Limits With The Previous Permit Existing Permit Proposed Permit

Parameter Average Monthly

Average Weekly

Average Monthly

Average Weekly

BOD5, in mg/L; lbs/day

30 mg/L, 48

lbs/day

45 mg/L, 71

lbs/day

10 mg/L,

15.8 lbs/day

15 mg/L,

23.6 lbs/day TSS, in mg/L; lbs/day

30 mg/L, 48

lbs/day

45 mg/L, 71

lbs/day

30 mg/L, 48

lbs/day

45 mg/L, 71

lbs/day pH

Between 6 and 9 standard units

at all times

Between 6 and 9 standard units

at all times Fecal Coliform Bacteria, in #colonies/100 mL

100

200

100

200

Parameter

Average Monthly

Maximum Daily

Average Monthly

Maximum Daily

Ammonia, in mg/L

None

None

20.0

34.6

Dissolved Oxygen, mg/L

None 2 (minimum) 4 (minimum) 3 (minimum)

MONITORING REQUIREMENTS Monitoring, recording, and reporting are required (WAC 173-220-210 and 40 CFR 122.41) to verify that the treatment process is functioning correctly and the effluent limitations are being achieved. Monitoring of sludge quantity and quality is necessary to determine the appropriate uses of the sludge. Sludge monitoring is required by the current state and local solid waste management program and also by EPA under 40 CFR 503. The monitoring schedule is detailed in the proposed permit under Condition S.2. Specified monitoring frequencies take into account the quantity and variability of discharge, the treatment method, past compliance, significance of pollutants, and cost of monitoring. The required monitoring frequency is consistent with agency guidance given in the current version of Ecology’s Permit Writer's Manual (July 1994) for activated sludge plants with an average design flow of less than 2.0 MGD.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 25 of 51 EXPIRATION DATE: APRIL 30, 2012 Additional monitoring is required in order to further characterize the receiving water. This permit requires critical period receiving water monitoring (July to September) during 2009 and 2010. Samples will be collected a minimum of 100 feet upstream of the outfall. Samples will be analyzed for alkalinity, hardness, dissolved oxygen, fecal coliform bacteria, temperature, and pH. Sampling and analysis for phosphorus is being conducted by others. LAB ACCREDITATION With the exception of certain parameters the permit requires all monitoring data to be prepared by a laboratory registered or accredited under the provisions of Chapter 173-50 WAC, Accreditation of Environmental Laboratories. The laboratory at this facility is accredited for Biochemical Oxygen Demand, Total Suspended Solids, pH, Dissolved Oxygen and Fecal Coliform Bacteria.

REPORTING AND RECORDKEEPING The conditions of S3 are based on the authority to specify any appropriate reporting and recordkeeping requirements to prevent and control waste discharges (WAC 173-220-210). PREVENTION OF FACILITY OVERLOADING Overloading of the treatment plant is a violation of the terms and conditions of the permit. To prevent this from occurring, RCW 90.48.110 and WAC 173-220-150 require the Permittee to take the actions detailed in proposed permit requirement S4, including plans for expansions or modifications, before existing capacity is reached and to report and correct conditions that could result in new or increased discharges of pollutants. Condition S4. restricts the amount of flow to the facility design flow. A Plan to Maintain Adequate Capacity is required when design parameters reach 85% of design capacity. A draft plan was prepared during the previous permit period, but was not approved. Table 4 above includes the design criteria from the June 2000 Operations and Maintenance manual and Engineering Report (Esvelt and Spink 2000; 1993). Recent Mabton POTW data is compared to 85% of design in Table 11 below.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 26 of 51 EXPIRATION DATE: APRIL 30, 2012 Table 11: Comparison of Recent Data with 85% of Design Standards for Mabton WWTP

Parameter 85% of Capacity 3-Year Average 1-Year Average

Maximum Month Flow

0.161 MGD

0.208*

0.208*

Annual Average Flow

0.141 MGD 0.154* 0.166*

Maximum Daily Flow

0.425 MGD (instantaneous peak)

0.986* 0.986*

BOD5 Annual Average

406 lbs/day 362 343

TSS Annual Average

385 lbs/day 324 330

* Exceeds 85% of design capacity. A Plan to Maintain Adequate Capacity will be required by Permit condition S4. In addition to addressing capacity and sludge-handling, the plan will identify options to increase dissolved oxygen and decrease temperature in the effluent. OPERATION AND MAINTENANCE (O&M) The proposed permit contains condition S5, authorized under RCW 90.48.110, WAC 173-220-150, Chapter 173-230 WAC, and WAC 173-240-080. It is included to ensure proper operation and regular maintenance of equipment, and to ensure that adequate safeguards are taken so that constructed facilities are used to their optimum potential in terms of pollutant capture and treatment. If significant process changes are made during the period of this permit, an updated Operations and Maintenance manual will be submitted for review. Inflow and Infiltration Because of the difference in flow between wet and dry years, leaks may be present in significant quantities or in sensitive locations. The permit will require the collection system to be evaluated for the presence of excessive inflow and infiltration in accordance with the Environmental Protection Agency (EPA) publication “Infiltration/Inflow: I/I analysis and project certification” (EPA 1985a). Other references are:

• American Society of Civil Engineers and Water Environment Federation Manual of Practice FD-6. Existing Sewer Evaluation and Rehabilitation


• U.S. Environmental Protection Agency. Handbook for Sewer System Infrastructure Analysis and Rehabilitation. EPA/625/6-91/030. 1991

• Washington State Department of Transportation. Standard Specifications for Road,

Bridge, and Municipal Construction. 2002. RESIDUAL SOLIDS HANDLING To prevent water quality problems the Permittee is required in permit condition S7. to store and handle all residual solids (grit, screenings, scum, sludge, and other solid waste) in accordance with the requirements of RCW 90.48.080 and State Water Quality Standards. The final use and disposal of sewage sludge from this facility is regulated by U.S. EPA under 40 CFR 503, and by Ecology under Chapter 70.95J RCW, Chapter 173-308 WAC “Biosolids Management,” and Chapter 173-350 WAC “Solid Waste Handling Standards.” The disposal of other solid waste is under the jurisdiction of the Yakima County Health Department. Biosolids are transported for land application by Natural Selection Farms in accordance with the Final Coverage granted to Natural Selection Farms under the Statewide General Permit for Biosolids Management. PRETREATMENT The department may modify this permit to incorporate additional requirements relating to the establishment and enforcement of local limits for pollutants of concern. Any permit modification is subject to formal due process procedures pursuant to state and federal law and regulation. Federal and State Pretreatment Program Requirements Under the terms of the addendum to the “Memorandum of Understanding between Washington Department of Ecology and the United States Environmental Protection Agency, Region 10” (1986), the Department of Ecology (Department) has been delegated authority to administer the Pretreatment Program [i.e., act as the Approval Authority for oversight of delegated Publicly Owned Treatment Works (POTWs)]. Under this delegation of authority, the department has exercised the option of issuing wastewater discharge permits for significant industrial users discharging to POTWs which have not been delegated authority to issue wastewater discharge permits. There are a number of functions required by the Pretreatment Program which the department is delegating to such POTWs because they are in a better position to implement the requirements (e.g., tracking the number and general nature of industrial dischargers to the sewerage system). The requirements for a Pretreatment Program are contained in Title 40, part 403 of the Code of

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 28 of 51 EXPIRATION DATE: APRIL 30, 2012 Federal Regulations. Under the requirements of the Pretreatment Program (40 CFR 403.8(f)(1)(iii)), the department is required to approve, condition, or deny new discharges or a significant increase in the discharge for existing significant industrial users (SIUs) ( 40 CFR 403.8 (f)(1)(i)). The department is responsible for issuing State Waste Discharge Permits to SIUs and other industrial users of the Permittee's sewer system. Industrial dischargers must obtain these permits from the department prior to the permittee accepting the discharge (WAC 173-216-110(5)) (Industries discharging wastewater that is similar in character to domestic wastewater are not required to obtain a permit. Such dischargers should contact the department to determine if a permit is required.). Industrial dischargers need to apply for a State Waste Discharge Permit sixty days prior to commencing discharge. The conditions contained in the permits will include any applicable conditions for categorical discharges, loading limitations included in contracts with the POTW, and other conditions necessary to assure compliance with State water quality standards and biosolids standards. The department requires this POTW to fulfill some of the functions required for the Pretreatment Program in the NPDES permit (e.g., tracking the number and general nature of industrial dischargers to the sewage system). The POTW's NPDES permit will require that all SIUs currently discharging to the POTW be identified and notified of the requirement to apply for a wastewater discharge permit from the department. None of the obligations imposed on the POTW relieve an industrial or commercial discharger of its primary responsibility for obtaining a wastewater discharge permit (if required), including submittal of engineering reports prior to construction or modification of facilities (40 CFR 403.12(j) and WAC 173-216-070 and WAC 173-240-110, et seq.). Wastewater Permit Required RCW 90.48 and WAC 173-216-040 require SIUs to obtain a permit prior to discharge of industrial waste to the Permittee's sewerage system. This provision prohibits the POTW from accepting industrial wastewater from any such dischargers without authorization from the department. Requirements for Routine Identification and Reporting of Industrial Users The NPDES permit requires non-delegated POTWs to " take continuous, routine measures to identify all existing, new, and proposed SIUs and potential significant industrial users (PSIUs) discharging to the Permittee's sewerage system". Examples of such routine measures include regular review of business tax licenses for existing businesses and review of water billing records and existing connection authorization records. System maintenance personnel can also be diligent during performance of their jobs in identifying and reporting as-yet unidentified industrial dischargers. Local newspapers, telephone directories, and word-of-mouth can also be important sources of information regarding new or existing discharges. The POTW is required

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 29 of 51 EXPIRATION DATE: APRIL 30, 2012 to notify an industrial discharger, in writing, of its responsibilities regarding application for a State waste discharge permit and to send a copy of the written notification to the department. The department will then take steps to solicit a State waste discharge permit application. Duty to Enforce Discharge Prohibitions This provision prohibits the POTW from authorizing or permitting an industrial discharger to discharge certain types of waste into the sanitary sewer. The first portion of the provision prohibits acceptance of pollutants which cause pass through or interference. The definitions of pass through and interference are in Appendix B of the fact sheet. The second portion of this provision prohibits the POTW from accepting certain specific types of wastes, namely those which are explosive, flammable, excessively acidic, basic, otherwise corrosive, or obstructive to the system. In addition, wastes with excessive BOD, petroleum based oils, or those that result in toxic gases are prohibited to be discharged. The regulatory basis for these prohibitions is 40 CFR Part 403, with the exception of the pH provisions which are based on WAC 173-216-060. The third portion of this provision prohibits certain types of discharges unless the POTW receives prior authorization from the department. The discharges include cooling water in significant volumes, stormwater and other direct inflow sources, and wastewaters significantly affecting system hydraulic loading, which do not require treatment. Support by the Department for Developing Partial Pretreatment Program by POTW The department has committed to providing technical and legal assistance to the permittee in fulfilling these joint obligations, in particular assistance with developing an adequate sewer use ordinance, notification procedures, enforcement guidelines, and developing local limits and inspection procedures. GENERAL CONDITIONS General Conditions are based directly on state and federal law and regulations and have been standardized for all individual municipal NPDES permits issued by the department. PERMIT MODIFICATIONS The department may modify this permit to impose numerical limitations, if necessary to meet Water Quality Standards, Sediment Quality Standards, or Ground Water Standards, based on new information obtained from sources such as inspections, effluent monitoring, outfall studies, and effluent mixing studies.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 30 of 51 EXPIRATION DATE: APRIL 30, 2012 The department may also modify this permit as a result of new or amended state or federal regulations. RECOMMENDATION FOR PERMIT ISSUANCE This proposed permit meets all statutory requirements for authorizing a wastewater discharge, including those limitations and conditions believed necessary to protect human health, aquatic life, and the beneficial uses of waters of the State of Washington. The department proposes that this permit be issued for 5 years.


REFERENCES FOR TEXT AND APPENDICES US Environmental Protection Agency (EPA)

1992. National Toxics Rule. Federal Register, V. 57, No. 246, Tuesday, December 22, 1992. 1991. Technical Support Document for Water Quality-based Toxics Control. EPA/505/2-90-

001. 1988. Technical Guidance on Supplementary Stream Design Conditions for Steady State

Modeling. USEPA Office of Water, Washington, D.C. 1985a. Infiltration/Inflow: I/I Analysis and Project Certification . Ecology Publication No.

97-03 (http://www.ecy.wa.gov/pubs/9703.pdf.) 1985b. Water Quality Assessment: A Screening Procedure for Toxic and Conventional

Pollutants in Surface and Ground Water. EPA/600/6-85/002a. 1983. Water Quality Standards Handbook. USEPA Office of Water, Washington, D.C.

Esvelt, M. 1993. City of Mabton, Engineering Report for Wastewater Treatment System. Esvelt Environmental Engineering, Spokane, WA. August 29, 2003.

Esvelt, L. and Spink, R. 1993. Mabton Washington, Annual Wasteload Assessment. Esvelt Environmental Engineering, Spokane, WA.; Spink Engineering, Richland, WA.

Esvelt, L. and Spink, R. 2000. City of Mabton, Wastewater Treatment Plant, Operations and

Maintenance Manual. Esvelt Environmental Engineering, Spokane, WA.; Spink Engineering, Richland, WA; Conley Engineering, Yakima, WA; and , Structural Research Company, Spokane, WA.

Metcalf and Eddy.

1991. Wastewater Engineering, Treatment, Disposal, and Reuse. Third Edition.

Spink, R. and Conley, P. 2001. Mabton Wastewater Treatment Plant Improvements, As-Built Record Drawings. Spink Engineering, Richland, WA; Conley Engineering, Yakima, WA; Esvelt Environmental Engineering, Spokane, WA., and , Structural Research Company, Spokane, WA.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 32 of 51 EXPIRATION DATE: APRIL 30, 2012 Tsivoglou, E.C., and J.R. Wallace.

1972. Characterization of Stream Reaeration Capacity. EPA-R3-72-012. (Cited in EPA 1985

op.cit.)

USDOI Bureau of Reclamation 2002. Interim Comprehensive Basin Operating Plan for the Yakima Project, Washington. US Department of the Interior, Bureau of Reclamation, Pacific Northwest Region, Upper Columbia Area Office, Yakima, Washington.

USDOI Bureau of Reclamation 2004. Finding of No Significant Impact and Final

Environmental Assessment ; Sunnyside Division Board of Control, Water Conservation Program Yakima Project, Washington. US Department of the Interior, Bureau of Reclamation, Pacific Northwest Region, Upper Columbia Area Office, Yakima, Washington.

Washington State Department of Ecology. Laws and Regulations( http://www.ecy.wa.gov/laws-rules/index.html ) Permit and Wastewater Related Information

(http://www.ecy.wa.gov/programs/wq/wastewater/index.html Washington State Department of Ecology. 1994. Permit Writer’s Manual. Publication Number 92-109 Water Pollution Control Federation.

1976. Chlorination of Wastewater.

Wright, R.M., and A.J. McDonnell.

1979. In-stream Deoxygenation Rate Prediction. Journal Environmental Engineering

Division, ASCE. 105(EE2). (Cited in EPA 1985 op.cit.)

Zuroske, M. 2006. Personal communication. South Yakima Conservation District. Yakima, WA.

http://www.ecy.wa.gov/laws-rules/index.html

http://www.ecy.wa.gov/programs/wq/wastewater/index.html


APPENDIX A--PUBLIC INVOLVEMENT INFORMATION

The Department has tentatively determined to reissue a permit to the applicant listed on page 1 of this fact sheet. The permit contains conditions and effluent limitations which are described in the rest of this fact sheet. Public notice of application was published on July 6, 2006 in the Yakima Herald Republic to inform the public that an application had been submitted and to invite comment on the reissuance of this permit. The Department will publish a Public Notice of Draft (PNOD) on January 30, 2007 in the Yakima Herald Republic to inform the public that a draft permit and fact sheet are available for review. Interested persons are invited to submit written comments regarding the draft permit. The draft permit, fact sheet, and related documents are available for inspection and copying between the hours of 8:00 a.m. and 5:00 p.m. weekdays, by appointment, at the regional office listed below. Written comments should be mailed to:

Water Quality Permit Coordinator Department of Ecology Central Regional Office 15 West Yakima Avenue, Suite 200 Yakima, WA 98902

Any interested party may comment on the draft permit or request a public hearing on this draft permit within the 30 day comment period to the address above. The request for a hearing shall indicate the interest of the party and the reasons why the hearing is warranted. The Department will hold a hearing if it determines there is a significant public interest in the draft permit (WAC 173-220-090). Public notice regarding any hearing will be circulated at least 30 days in advance of the hearing. People expressing an interest in this permit will be mailed an individual notice of hearing (WAC 173-220-100). Comments should reference specific text followed by proposed modification or concern when possible. Comments may address technical issues, accuracy and completeness of information, the scope of the facility’s proposed coverage, adequacy of environmental protection, permit conditions, or any other concern that would result from issuance of this permit. The Department will consider all comments received within 30 days from the date of public notice of draft indicated above, in formulating a final determination to issue, revise, or deny the permit. The Department's response to all significant comments is available upon request and will be mailed directly to people expressing an interest in this permit. Further information may be obtained from the Department by telephone, 509/457-7105, or by writing to the address listed above. Jean Hays wrote this permit and fact sheet.


APPENDIX B--GLOSSARY Acute Toxicity--The lethal effect of a pollutant on an organism that occurs within a short period

of time, usually 48 to 96 hours. AKART-- An acronym for “all known, available, and reasonable methods of prevention, control,

and treatment”. Ambient Water Quality--The existing environmental condition of the water in a receiving

water body. Ammonia--Ammonia is produced by the breakdown of nitrogenous materials in wastewater.

Ammonia is toxic to aquatic organisms, exerts an oxygen demand, and contributes to eutrophication. It also increases the amount of chlorine needed to disinfect wastewater.

Average Monthly Discharge Limitation --The highest allowable average of daily discharges

over a calendar month, calculated as the sum of all daily discharges measured during a calendar month divided by the number of daily discharges measured during that month (except in the case of fecal coliform). The daily discharge is calculated as the average measurement of the pollutant over the day.

Average Weekly Discharge Limitation -- The highest allowable average of daily discharges

over a calendar week, calculated as the sum of all daily discharges measured during a calendar week divided by the number of daily discharges measured during that week. The daily discharge is calculated as the average measurement of the pollutant over the day.

Best Management Practices (BMPs)--Schedules of activities, prohibitions of practices,

maintenance procedures, and other physical, structural and/or managerial practices to prevent or reduce the pollution of waters of the State. BMPs include treatment systems, operating procedures, and practices to control: plant site runoff, spillage or leaks, sludge or waste disposal, or drainage from raw material storage. BMPs may be further categorized as operational, source control, erosion and sediment control, and treatment BMPs.

BOD5--Determining the Biochemical Oxygen Demand of an effluent is an indirect way of

measuring the quantity of organic material present in an effluent that is utilized by bacteria. The BOD5 is used in modeling to measure the reduction of dissolved oxygen in a receiving water after effluent is discharged. Stress caused by reduced dissolved oxygen levels makes organisms less competitive and less able to sustain their species in the aquatic environment. Although BOD is not a specific compound, it is defined as a conventional pollutant under the federal Clean Water Act.

Bypass--The intentional diversion of waste streams from any portion of a treatment facility.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 35 of 51 EXPIRATION DATE: APRIL 30, 2012 CBOD5 – The quantity of oxygen utilized by a mixed population of microorganisms acting on

the nutrients in the sample in an aerobic oxidation for five days at a controlled temperature of 20 degrees Celsius, with an inhibitory agent added to prevent the oxidation of nitrogen compounds. The method for determining CBOD5 is given in 40 CFR Part 136.

Chlorine--Chlorine is used to disinfect wastewaters of pathogens harmful to human health. It is

also extremely toxic to aquatic life. Chronic Toxicity--The effect of a pollutant on an organism over a relatively long time, often

1/10 of an organism's lifespan or more. Chronic toxicity can measure survival, reproduction or growth rates, or other parameters to measure the toxic effects of a compound or combination of compounds.

Clean Water Act (CWA)--The Federal Water Pollution Control Act enacted by Public Law 92-

500, as amended by Public Laws 95-217, 95-576, 96-483, 97-117; USC 1251 et seq. Combined Sewer Overflow (CSO)--The event during which excess combined sewage flow

caused by inflow is discharged from a combined sewer, rather than conveyed to the sewage treatment plant because either the capacity of the treatment plant or the combined sewer is exceeded.

Compliance Inspection - Without Sampling--A site visit for the purpose of determining the

compliance of a facility with the terms and conditions of its permit or with applicable statutes and regulations.

Compliance Inspection - With Sampling--A site visit to accomplish the purpose of a

Compliance Inspection - Without Sampling and as a minimum, sampling and analysis for all parameters with limits in the permit to ascertain compliance with those limits; and, for municipal facilities, sampling of influent to ascertain compliance with the percent removal requirement. Additional sampling may be conducted.

Composite Sample--A mixture of grab samples collected at the same sampling point at different

times, formed either by continuous sampling or by mixing a minimum of four discrete samples. May be "time-composite"(collected at constant time intervals) or "flow-proportional" (collected either as a constant sample volume at time intervals proportional to stream flow, or collected by increasing the volume of each aliquot as the flow increased while maintaining a constant time interval between the aliquots).

Construction Activity--Clearing, grading, excavation and any other activity which disturbs the

surface of the land. Such activities may include road building, construction of residential houses, office buildings, or industrial buildings, and demolition activity.

Continuous Monitoring –Uninterrupted, unless otherwise noted in the permit.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 36 of 51 EXPIRATION DATE: APRIL 30, 2012 Critical Condition--The time during which the combination of receiving water and waste

discharge conditions have the highest potential for causing toxicity in the receiving water environment. This situation usually occurs when the flow within a water body is low, thus, its ability to dilute effluent is reduced.

Dilution Factor--A measure of the amount of mixing of effluent and receiving water that occurs

at the boundary of the mixing zone. Expressed as the inverse of the effluent fraction e.g., a dilution factor of 10 means the effluent comprises 10% by volume and the receiving water 90%.

Engineering Report--A document which thoroughly examines the engineering and

administrative aspects of a particular domestic or industrial wastewater facility. The report shall contain the appropriate information required in WAC 173-240-060 or 173-240-130.

Fecal Coliform Bacteria--Fecal coliform bacteria are used as indicators of pathogenic bacteria

in the effluent that are harmful to humans. Pathogenic bacteria in wastewater discharges are controlled by disinfecting the wastewater. The presence of high numbers of fecal coliform bacteria in a water body can indicate the recent release of untreated wastewater and/or the presence of animal feces.

Grab Sample--A single sample or measurement taken at a specific time or over as short period

of time as is feasible. Industrial User-- A discharger of wastewater to the sanitary sewer which is not sanitary

wastewater or is not equivalent to sanitary wastewater in character. Industrial Wastewater--Water or liquid-carried waste from industrial or commercial processes,

as distinct from domestic wastewater. These wastes may result from any process or activity of industry, manufacture, trade or business, from the development of any natural resource, or from animal operations such as feed lots, poultry houses, or dairies. The term includes contaminated storm water and, also, leachate from solid waste facilities.

Infiltration and Inflow (I/I)--"Infiltration" means the addition of ground water into a sewer

through joints, the sewer pipe material, cracks, and other defects. "Inflow" means the addition of precipitation-caused drainage from roof drains, yard drains, basement drains, street catch basins, etc., into a sewer.

Interference -- A discharge which, alone or in conjunction with a discharge or discharges from

other sources, both: Inhibits or disrupts the POTW, its treatment processes or operations, or its sludge processes,

use or disposal and;

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 37 of 51 EXPIRATION DATE: APRIL 30, 2012 Therefore is a cause of a violation of any requirement of the POTW's NPDES permit

(including an increase in the magnitude or duration of a violation) or of the prevention of sewage sludge use or disposal in compliance with the following statutory provisions and regulations or permits issued thereunder (or more stringent State or local regulations): Section 405 of the Clean Water Act, the Solid Waste Disposal Act (SWDA) (including title II, more commonly referred to as the Resource Conservation and Recovery Act (RCRA), and including State regulations contained in any State sludge management plan prepared pursuant to subtitle D of the SWDA), sludge regulations appearing in 40 CFR Part 507, the Clean Air Act, the Toxic Substances Control Act, and the Marine Protection, Research and Sanctuaries Act.

Major Facility--A facility discharging to surface water with an EPA rating score of > 80 points

based on such factors as flow volume, toxic pollutant potential, and public health impact. Maximum Daily Discharge Limitation--The highest allowable daily discharge of a pollutant

measured during a calendar day or any 24-hour period that reasonably represents the calendar day for purposes of sampling. The daily discharge is calculated as the average measurement of the pollutant over the day.

Method Detection Level (MDL)--The minimum concentration of a substance that can be

measured and reported with 99% confidence that the analyte concentration is above zero and is determined from analysis of a sample in a given matrix containing the analyte.

Minor Facility--A facility discharging to surface water with an EPA rating score of < 80 points

based on such factors as flow volume, toxic pollutant potential, and public health impact. Mixing Zone--A volume that surrounds an effluent discharge within which water quality criteria

may be exceeded. The area of the authorized mixing zone is specified in a facility's permit and follows procedures outlined in State regulations (Chapter 173-201A WAC).

National Pollutant Discharge Elimination System (NPDES)--The NPDES (Section 402 of the

Clean Water Act) is the Federal wastewater permitting system for discharges to navigable waters of the United States. Many states, including the State of Washington, have been delegated the authority to issue these permits. NPDES permits issued by Washington State permit writers are joint NPDES/State permits issued under both State and Federal laws.

Pass through -- A discharge which exits the POTW into waters of the State in quantities or

concentrations which, alone or in conjunction with a discharge or discharges from other sources, is a cause of a violation of any requirement of the POTW's NPDES permit (including an increase in the magnitude or duration of a violation), or which is a cause of a violation of State water quality standards.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 38 of 51 EXPIRATION DATE: APRIL 30, 2012 pH--The pH of a liquid measures its acidity or alkalinity. A pH of 7 is defined as neutral, and

large variations above or below this value are considered harmful to most aquatic life. Potential Significant Industrial User--A potential significant industrial user is defined as an

Industrial User which does not meet the criteria for a Significant Industrial User, but which discharges wastewater meeting one or more of the following criteria:

a. Exceeds 0.5 % of treatment plant design capacity criteria and discharges <25,000 gallons

per day or; b. Is a member of a group of similar industrial users which, taken together, have the

potential to cause pass through or interference at the POTW (e.g. facilities which develop photographic film or paper, and car washes).

The Department may determine that a discharger initially classified as a potential significant

industrial user should be managed as a significant industrial user. Quantitation Level (QL)-- A calculated value five times the MDL (method detection level). Significant Industrial User (SIU)-- 1) All industrial users subject to Categorical Pretreatment Standards under 40 CFR 403.6 and

40 CFR Chapter I, Subchapter N and; 2) Any other industrial user that: discharges an average of 25,000 gallons per day or more of

process wastewater to the POTW (excluding sanitary, noncontact cooling, and boiler blow-down wastewater); contributes a process wastestream that makes up 5 percent or more of the average dry weather hydraulic or organic capacity of the POTW treatment plant; or is designated as such by the Control Authority* on the basis that the industrial user has a reasonable potential for adversely affecting the POTW's operation or for violating any pretreatment standard or requirement (in accordance with 40 CFR 403.8(f)(6)).

Upon finding that the industrial user meeting the criteria in paragraph 2, above, has no

reasonable potential for adversely affecting the POTW's operation or for violating any pretreatment standard or requirement, the Control Authority* may at any time, on its own initiative or in response to a petition received from an industrial user or POTW, and in accordance with 40 CFR 403.8(f)(6), determine that such industrial user is not a significant industrial user.

*The term "Control Authority" refers to the Washington State Department of Ecology in the

case of non-delegated POTWs or to the POTW in the case of delegated POTWs.

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 39 of 51 EXPIRATION DATE: APRIL 30, 2012 State Waters--Lakes, rivers, ponds, streams, inland waters, underground waters, salt waters,

wetlands, and all other surface waters and watercourses within the jurisdiction of the state of Washington.

Stormwater--That portion of precipitation that does not naturally percolate into the ground or

evaporate, but flows via overland flow, interflow, pipes, and other features of a storm water drainage system into a defined surface water body, or a constructed infiltration facility.

Technology-based Effluent Limit--A permit limit that is based on the ability of a treatment

method to reduce the pollutant. Total Suspended Solids (TSS)--Total suspended solids are the particulate materials in an

effluent. Large quantities of TSS discharged to receiving water may result in solids accumulation. Apart from any toxic effects attributable to substances leached out by water, suspended solids may kill fish, shellfish, and other aquatic organisms by causing abrasive injuries and by clogging the gills and respiratory passages of various aquatic fauna. Indirectly, suspended solids can screen out light and can promote and maintain the development of noxious conditions through oxygen depletion.

Upset--An exceptional incident in which there is unintentional and temporary noncompliance

with technology-based permit effluent limitations because of factors beyond the reasonable control of the Permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, lack of preventative maintenance, or careless or improper operation.

Water Quality-based Effluent Limit--A limit on the concentration or mass of an effluent

parameter that is intended to prevent the concentration of that parameter from exceeding its water quality criterion after it is discharged into receiving water.


APPENDIX C -- DATA AND TECHNICAL CALCULATIONS Several of the Excel® spreadsheet tools used to evaluate a discharger’s ability to meet Washington State water quality standards can be found on the Department’s homepage at (http://www.ecy.wa.gov/programs/wq/wastewater/index.html

Effluent Data Summary

http://www.ecy.wa.gov/programs/wq/wastewater/index.html

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 42 of 51 EXPIRATION DATE: APRIL 30, 2012 Influent Data Summary

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 43 of 51 EXPIRATION DATE: APRIL 30, 2012 Receiving Water Data

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 44 of 51 EXPIRATION DATE: APRIL 30, 2012 Dilution Factor Calculations Volume Fraction Equation

Volume Fraction Calculations

Peaking Factor: critical period daily maxium/ monthly average critical period daily maximum = 0.1979monthly average = 0.1546Peaking Factor: 1.28008

mgd cfsacute flow with peaking factor 0.253 0.391477

chronic flow 0.172 0.266142

Dilution factor = (Q ambient fraction of 7Q10 critial season flow + effluent flow rate)/ (effluent flow rate)Chronic ambient fraction: 25%Acute ambient fraction: 2.5%Receiving water 7Q10 cfs: 300Acute DF: 20.15823788Chronic DF: 282.804313

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 45 of 51 EXPIRATION DATE: APRIL 30, 2012 RivPlume5 Model

Spread of a plume from a point source in a river with boundary effects from the shorelinebased on the method of Fischer et al. (1979) with correction for the effective origin of effluent.

Revised 22-Feb-96

INPUTChronic Acute

1. Effluent Discharge Rate (cfs): 0.27 0.39

2. Receiving Water Characteristics Downstream From Waste Input Stream Depth (ft): 7.50 7.50 Stream Velocity (fps): 0.22 0.22 Channel Width (ft): 180.00 180.00 Stream Slope (ft/ft) or Manning roughness "n": 0.033 0.033 0 if slope or 1 if Manning "n" in previous cell: 1 1

3. Discharge Distance From Nearest Shoreline (ft): 0 0

4. Location of Point of Interest to Estimate Dilution Distance Downstream to Point of Interest (ft): 300 30 Distance From Nearest Shoreline (ft): 0 0

5. Transverse Mixing Coefficient Constant (usually 0.6): 0.6 0.6

6. Original Fischer Method (enter 0) or Effective Origin Modification (enter 1) 0 0

OUTPUT

1. Source Conservative Mass Input Rate Concentration of Conservative Substance (%): 100.00 100.00 Source Conservative Mass Input Rate (cfs*%): 26.61 39.10

2. Shear Velocity Shear Velocity based on slope (ft/sec): #N/A #N/A Shear Velocity based on Manning "n": using Prasuhn equations 8-26 and 8-54 assuming hydraulic radius equals depth for wide channel Darcy-Weisbach friction factor "f": 0.065 0.065 Shear Velocity from Darcy-Weisbach "f" (ft/sec): 0.020 0.020 Selected Shear Velocity for next step (ft/sec): 0.020 0.020

3. Transverse Mixing Coefficient (ft2/sec): 0.090 0.090

4. Plume Characteristics Accounting for Shoreline Effect (Fischer et al. , 1979) Co 8.88E-02 1.30E-01 x' 3.74E-03 3.74E-04 y'o 0.00E+00 0.00E+00 y' at point of interest 0.00E+00 0.00E+00 Solution using superposition equation (Fischer eqn 5.9) Term for n= -2 0.00E+00 0.00E+00 Term for n= -1 1.85E-116 0.00E+00 Term for n= 0 2.00E+00 2.00E+00 Term for n= 1 1.85E-116 0.00E+00 Term for n= 2 0.00E+00 0.00E+00 Upstream Distance from Outfall to Effective Origin of Effluent Source (ft) #N/A #N/A Effective Distance Downstream from Effluent to Point of Interest (ft) 300.00 30.00 x' Adjusted for Effective Origin 3.74E-03 3.74E-04 C/Co (dimensionless) 9.22E+00 2.92E+01 Concentration at Point of Interest (Fischer Eqn 5.9) 8.19E-01 3.80E+00 Unbounded Plume Width at Point of Interest (ft) 62.294 19.699 Unbounded Plume half-width (ft) 31.147 9.850 Distance from near shore to discharge point (ft) 0.00 0.00 Distance from far shore to discharge point (ft) 180.00 180.00 Plume width bounded by shoreline (ft) 31.15 9.85

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 46 of 51 EXPIRATION DATE: APRIL 30, 2012 Dissolved Oxygen Calculation

Dissolved oxygen concentration following initial dilution.References: EPA/600/6-85/002b and EPA/430/9-82-011

Based on Lotus File IDOD2.WK1 Revised 19-Oct-93

INPUT

1. Dilution Factor at Mixing Zone Boundary: 1

2. Ambient Dissolved Oxygen Concentration (mg/L): 7.11

3. Effluent Dissolved Oxygen Concentration (mg/L): 4.27

4. Effluent Immediate Dissolved Oxygen Demand (mg/L): 0

OUTPUT

Dissolved Oxygen at Mixing Zone Boundary (mg/L): 4.27

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 47 of 51 EXPIRATION DATE: APRIL 30, 2012 Streeter-Phelps analysis of critical dissolved oxygen sag resulting from Biochemical Oxygen Demand.

Streeter-Phelps analysis of critical dissolved oxygen sag.

Based on Lotus File DOSAG2.WK1 Revised 19-Oct-93

INPUT

1. EFFLUENT CHARACTERISTICS Discharge (cfs): 0.29245 design max month CBOD5 (mg/L): 8.75 for BOD5=10 NBOD (mg/L): 1.25 for BOD5=10 Dissolved Oxygen (mg/L): 4.27 3-yr ave Temperature (deg C): 23.83 max mo

2. RECEIVING WATER CHARACTERISTICS Upstream Discharge (cfs): 300 7Q10 Upstream CBOD5 (mg/L): 0.3 est Upstream NBOD (mg/L): 0.04 est Upstream Dissolved Oxygen (mg/L): 7.11 lower 10th percentile Upstream Temperature (deg C): 21.94 ave crit period Elevation (ft NGVD): 640 Downstream Average Channel Slope (ft/ft): 0.00088 Downstream Average Channel Depth (ft): 7.5 Downstream Average Channel Velocity (fps): 0.22

3. REAERATION RATE (Base e) AT 20 deg C (day^-1): 0.30

Reference Applic. Applic. SuggestedVel (fps) Dep (ft) Values

Churchill 1.5 - 6 2 - 50 0.09 O'Connor and Dobbins .1 - 1.5 2 - 50 0.30 Owens .1 - 6 1 - 2 0.19 Tsivoglou-Wallace .1 - 6 .1 - 2 0.80

4. BOD DECAY RATE (Base e) AT 20 deg C (day^-1): 0.63

Reference SuggestedValue

Wright and McDonnell, 1979 0.63

OUTPUT

1. INITIAL MIXED RIVER CONDITION CBOD5 (mg/L): 0.3 NBOD (mg/L): 0.0 Dissolved Oxygen (mg/L): 7.1 Temperature (deg C): 21.9

2. TEMPERATURE ADJUSTED RATE CONSTANTS (Base e) Reaeration (day^-1): 0.31 BOD Decay (day^-1): 0.69

3. CALCULATED INITIAL ULTIMATE CBODU AND TOTAL BODU Initial Mixed CBODU (mg/L): 0.4 Initial Mixed Total BODU (CBODU + NBOD, mg/L): 0.5

4. INITIAL DISSOLVED OXYGEN DEFICIT Saturation Dissolved Oxygen (mg/L): 8.554 Initial Deficit (mg/L): 1.45

5. TRAVEL TIME TO CRITICAL DO CONCENTRATION (days): -0.50

6. DISTANCE TO CRITICAL DO CONCENTRATION (miles): -1.79

7. CRITICAL DO DEFICIT (mg/L): 1.48

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 48 of 51 EXPIRATION DATE: APRIL 30, 2012 pH Calculation

Calculation of pH of a mixture of two flows. Based on theprocedure in EPA's DESCON program (EPA, 1988. Technical

Guidance on Supplementary Stream Design Conditions for SteadyState Modeling. USEPA Office of Water, Washington D.C.)

Based on Lotus File PHMIX2.WK1 Revised 19-Oct-93

INPUTchronic acute

1. DILUTION FACTOR AT MIXING ZONE BOUNDARY 122.130 20.160

2. UPSTREAM/BACKGROUND CHARACTERISTICS Temperature (deg C): 22.78 22.78 pH: 8.26 8.26 Alkalinity (mg CaCO3/L): 90.00 90.00

3. EFFLUENT CHARACTERISTICS Temperature (deg C): 23.83 23.83 pH: 8.40 8.40 Alkalinity (mg CaCO3/L): 240.00 240.00

OUTPUT

1. IONIZATION CONSTANTS Upstream/Background pKa: 6.36 6.36 Effluent pKa: 6.36 6.36

2. IONIZATION FRACTIONS Upstream/Background Ionization Fraction: 0.99 0.99 Effluent Ionization Fraction: 0.99 0.99

3. TOTAL INORGANIC CARBON Upstream/Background Total Inorganic Carbon (mg CaCO3/L): 91.14 91.14 Effluent Total Inorganic Carbon (mg CaCO3/L): 242.17 242.17

4. CONDITIONS AT MIXING ZONE BOUNDARY Temperature (deg C): 22.79 22.83 Alkalinity (mg CaCO3/L): 91.23 97.44 Total Inorganic Carbon (mg CaCO3/L): 92.38 98.63 pKa: 6.36 6.36

pH at Mixing Zone Boundary: 8.26 8.28

FACT SHEET FOR CITY OF MABTON POTW NPDES PERMIT NO. WA-002064-8 Page 49 of 51 EXPIRATION DATE: APRIL 30, 2012 Ammonia Criteria

INPUT 1. Ambient Temperature (deg C; 0<T<30) 22.8

2. Ambient pH (6.5<pH<9.0) 8.26

3. Acute TCAP (Salmonids present- 20; absent- 25) 20

4. Chronic TCAP (Salmonids present- 15; absent- 20) 15

OUTPUT 1. Intermediate Calculations: Acute FT 1.00 Chronic FT 1.41 FPH 1.00 RATIO 14 pKa 9.31 Fraction Of Total Ammonia Present As Un-ionized 8.1334%

2. Un-ionized Ammonia Criteria Acute (1-hour) Un-ionized Ammonia Criterion (ug NH3/L) 260.0 Chronic (4-day) Un-ionized Ammonia Criterion (ug NH3/L) 42.0

3. Total Ammonia Criteria: Acute Total Ammonia Criterion (mg NH3+ NH4/L) 3.2 Chronic Total Ammonia Criterion (mg NH3+ NH4/L) 0.5

4. Total Ammonia Criteria expressed as Nitrogen: Acute Ammonia Criterion as mg N 2.6 Chronic Ammonia Criterion as N 0.42

Calculation Of Ammonia Concentration and Criteria for fresh water. Based on EPA Quality Criteria for Water (EPA 400/5-86-001) and WAC 173-201A. Revised 1-5-94 (corrected total ammonia criterion). Revised 3/10/95 to calculate chronic criteria in accordance with EPA Memorandum from Heber to WQ Stds Coordinators dated July 30, 1992.

Ammonia Reasonable Potential Analysis

State Water Quality Standard

Metal Criteria Translator as

decimal

Metal Criteria Translator as

decimal

Ambient Concentration (metals as

dissolved) Acute ChronicParameter Acute Chronic ug/L ug/L ug/L

Max concentration at edge of...

Acute Mixing Zone

Chronic Mixing Zone

LIMIT REQ'D?

ug/L ug/Lammonia 1.00 1.00 330.0000 3200.0000 500.0000 1683.50 553.92 YES


MultiplierPn s

0.90 0.959 29200.00 0.55 72 0.95 20 122 eff=upper 90%

Max effluent conc.

measured (metals as total

recoverable)Coeff

Variation# of

samples

Acute Dil'n

Factor

Chronic Dil'n

Factorug/L CV n COMMENTS

0.60

Effluent percentile value

Ammonia Limit Calculation

Permit Limit Calculation Summary

Acute Dil'n

Factor

Chronic Dil'n

Factor

Metal Criteria Translat

or

Metal Criteria Translat

or

Ambient Concentr

ation

Water Quality

Standard Acute

Water Quality

Standard Chronic

PARAMETER Acute Chronic ug/L ug/L ug/L

Average Monthly

Limit (AML)

Maximum Daily Limit

(MDL) Commentsug/L ug/L

Ammonia 20.2 122.10 1.00 1.00 330.0000 3200.0000 500.0000 19993.6 34639.0

Dilution (Dil'n) factor is the inverse of the percent effluent concentration at the edge of the acute or chronic mixing zone.

Waste Load Allocation (WLA) and Long Term

Average (LTA) CalculationsStatistical variables for permit limit

calculationLTA

Coeff. Var. (CV)

Coeff. Var. (CV)

# of Samples

per Month

decimal

WLA Acute

WLA Chronic

LTA Acute

LTA Chronic

LTA Prob'y Basis

Limiting LTA

AML Prob'y Basis

MDL Prob'y Basis

ug/L ug/L ug/L ug/L decimal ug/L decimal decimal decimal n0.60 0.60 2.00 1.0058304 21087.00 18720.4 11122.0 0.99 11122.0 0.95 0.99

This spreadsheet calculates water quality based permit limits based on the two value steady state model using the State Water Quality standards contained in WAC 173-201A. The procedure and calculations are done per the procedure in


APPENDIX D--RESPONSE TO COMMENTS The following comments were received from Mark Esvelt, P.E., Esvelt Environmental Engineering: It appears that the Yakima River does not meet water quality standards for dissolved oxygen, and it is reasonable for discharges to review and evaluate their needs for effluent DO to help the DO in the River. However, it appears the new limitations in the permit will put the City in a position of frequent violations (based on the effluent quality summary presented in the fact sheet). A brief review suggests that the Mabton discharge may have negligible effect on the DO in the Yakima River. Perhaps because of dilution (such a small volume compared to the Yakima River flow, or perhaps the DOSAG2 spreadsheet is not an appropriate tool during critical low flows because of the river velocity, or some combination or complicating factors in river hydraulics. Response: The City of Mabton may conduct a dye study to determine dilution. However, a mixing zone is not allowed for parameters on Ecology’s 303(d) list for impaired water bodies.

APPENDIX B

DMR DATA SUMMARY

Avg 0.154 0.166 306 257 4.57 9.78 16.73 5.57 7.18

Max 0.473 0.965 799 1,336 15 75 29 450 8

Min 0.012 0.012 75 31 1 0 7 1 5

Flow Flow BOD TSS BOD TSS Temp Oxygen PH

Flow Flow mg/l mg/l mg/l mg/l Deg mg/l units

1/1/2006 0.180 0.180

1/2/2006 0.1796 0.1796

1/3/2006 0.1966 0.1966 13.6 4.84 7.34

1/4/2006 0.1884 0.1884 240 290 7 5 11.2 5.28 7.34

1/5/2006 0.1828 0.1828 11.4 5.23 7.34

1/6/2006 0.1902 0.1902 303 388 7 4 10.9 5.15 7.3

1/7/2006 0.1787 0.1787

1/8/2006 0.1836 0.1836

1/9/2006 0.1892 0.1892 12.5 4.94 7.27

1/10/2006 0.1734 0.1734 13.23 4.39 7.33

1/11/2006 0.1672 0.1672 12.6 3.95 7.32

1/12/2006 0.1748 0.1748 12.3 4.47 7.29

1/13/2006 0.1725 0.1725 201 174 5 3 12.7 4.65 7.33

1/14/2006 0.1873 0.1873

1/15/2006 0.1837 0.1837

1/16/2006 0.1749 0.1749

1/17/2006 0.1897 0.1897 8.5 4.86 7.27

1/18/2006 0.1773 0.1773 220 234 3 2 12.9 5.32 7.42

1/19/2006 0.1768 0.1768 12.1 5.03 7.36

1/20/2006 0.1736 0.1736 248 208 3 0.6 11.5 5.62 7.32

1/21/2006 0.1727 0.1727

1/22/2006 0.1895 0.1895

1/23/2006 0.1873 0.1873 11.8 5.55 7.29

1/24/2006 0.1805 0.1805 11.2 5.34 7.36

1/25/2006 0.1722 0.1722 225 298 3 0.2 11.4 5.85 7.33

1/26/2006 0.1862 0.1862 11.3 5.75 7.34

1/27/2006 0.1801 0.1801 331 170 2 0.2 11.7 5.66 7.33

1/28/2006 0.1966 0.1966

1/29/2006 0.1845 0.1845

1/30/2006 0.1741 0.1741 12.5 5.94 7.3

1/31/2006 11.8 5.4 7.35

2/1/2006 0.1921 0.1921 271 310 4 1.6 12 5.12 7.37

2/2/2006 0.1844 0.1844 12.2 5.09 7.36

2/3/2006 0.1769 0.1769 245 356 3 2.8 12.4 5.59 7.35

2/4/2006 0.1742 0.1742

2/5/2006 0.1834 0.1834

2/6/2006 0.1801 0.1801 11.3 5.58 7.3

2/7/2006 0.1833 0.1833 11.2 5.83 7.35

2/8/2006 0.1747 0.1747 287 450 4 1 11.8 4.9 7.28

2/9/2006 0.1687 0.1687 10.7 5.04 7.27

2/10/2006 0.1761 0.1761 262 276 4 1.6 10.8 4.91 7.27

2/11/2006 0.1797 0.1797

2/12/2006 0.1747 0.1747

2/13/2006 0.1672 0.1672 11.3 4.74 7.24

2/14/2006 0.1707 0.1707 11.1 4.79 7.3

2/15/2006 0.1768 0.1768 9.8 5.56 7.28

2/16/2006 0.1685 0.1685 10.8 5.52 7.28

2/17/2006 0.1506 0.1506 182 166 3 3 8.5 6.51 7.35

Influent Effluent

2/18/2006 0.1278 0.1278

2/19/2006 0.1037 0.1037

2/20/2006 0.1485 0.1485

2/21/2006 0.1716 0.1716 9.9 5.54 7.23

2/22/2006 0.1723 0.1723 214 258 3 0.2 11.3 5.14 7.31

2/23/2006 0.1754 0.1754 11.8 5.2 7.27

2/24/2006 0.1751 0.1751 237 210 4 0.4 10.9 4.5 7.28

2/25/2006 0.1777 0.1777

2/26/2006 0.1838 0.1838

2/27/2006 0.1891 0.1891 12.7 5.08 7.23

2/28/2006 0.1906 0.1906 12.5 5.4 7.3

3/1/2006 0.1958 0.1958 260 382 4 1 11.8 5.4 7.29

3/2/2006 0.1866 0.1866 12.5 5.14 7.29

3/3/2006 0.1902 0.1902 237 31 3 0.6 11.6 5.1 7.28

3/4/2006 0.1869 0.1869

3/5/2006 0.1837 0.1837

3/6/2006 0.1936 0.1936 12.3 5.1 7.25

3/7/2006 0.1842 0.1842 13.5 5.32 7.33

3/8/2006 0.1754 0.1754 250 314 3 7 12.3 5.35 7.3

3/9/2006 0.1811 0.1811 11 5.81 7.3

3/10/2006 0.1801 0.1801 221 248 4 0.6 11.1 5.66 7.31

3/11/2006 0.1702 0.1702

3/12/2006 0.1813 0.1813

3/13/2006 0.1754 0.1754 12.2 5.66 7.26

3/14/2006 0.1747 0.1747 12.8 5.62 7.34

3/15/2006 0.1755 0.1755 236 240 4 4 14.4 5.6 8.26

3/16/2006 0.1785 0.1785 12.4 5.7 7.29

3/17/2006 0.1769 0.1769 282 244 4 5 13 4.75 7.26

3/18/2006 0.1748 0.1748

3/19/2006 0.1899 0.1899

3/20/2006 0.1812 0.1812 7.2 5.06 7.27

3/21/2006 0.1717 0.1717 13.1 5.04 7.26

3/22/2006 0.1594 0.1594 276 130 4 0.8 14 5.13 7.27

3/23/2006 0.1497 0.1497 13.7 4.79 7.23

3/24/2006 0.15 0.15 326 244 6 0.2 14.8 5.02 7.25

3/25/2006 0.1662 0.1662

3/26/2006 0.1836 0.1836

3/27/2006 0.1812 0.1812 13 6.19 7.33

3/28/2006 0.1782 0.1782 15.3 4.82 7.27

3/29/2006 0.1666 0.1666 14.3 5.33 7.29

3/30/2006 0.1635 0.1635 14.3 5.31 7.31

3/31/2006 0.1694 0.1694 256 270 5 0.6 14.6 5.45 7.29

4/1/2006

4/2/2006

4/3/2006 0.165 0.165 14.6 5.08 7.2

4/4/2006 0.1682 0.1682 15 4.48 7.26

4/5/2006 0.1719 0.1719 261 248 5 2.6 14.9 3.79 7.23

4/6/2006 0.1676 0.1676 16.4 4.84 7.3

4/7/2006 0.1652 0.1652 249 212 4 1.4 15.2 5.04 7.34

4/8/2006 0.1612 0.1612

4/9/2006 0.1989 0.1989

4/10/2006 0.1786 0.1786 15.6 4.15 7.24

4/11/2006 0.1955 0.1955 14.7 4.42 7.3

4/12/2006 0.1756 0.1756 254 212 4 2.6 15.4 4.15 7.3

4/13/2006 0.1764 0.1764 15.8 3.88 7.32

4/14/2006 0.1685 0.1685 295 298 5 0.8 15.8 4.34 7.34

4/15/2006 0.1782 0.1782

4/16/2006 0.1877 0.1877

4/17/2006 0.1789 0.1789 14.1 4.47 7.41

4/18/2006 0.1735 0.1735 14.7 5.52 7.37

4/19/2006 0.1668 0.1668 251 252 3 0.2 13.6 4.71 7.34

4/20/2006 0.16 0.16 15.9 4.95 7.34

4/21/2006 0.1683 0.1683 251 210 3 0.2 16.4 5.2 7.34

4/22/2006 0.1715 0.1715

4/23/2006 0.1842 0.1842

4/24/2006 0.1782 0.1782 15.1 4.37 7.29

4/25/2006 0.1823 0.1823 15.7 4 7.31

4/26/2006 0.1715 0.1715 301 340 2 5.6 16.9 4.9 7.35

4/27/2006 0.172 0.172 16.2 4.41 7.35

4/28/2006 0.1644 0.1644 239 274 1 0.2 16.8 3.98 7.34

4/29/2006

4/30/2006

5/1/2006 0.1653 0.1653 16.6 4.28 7.39

5/2/2006 0.1696 0.1696 15.3 4.46 7.37

5/3/2006 0.1671 0.1671 242 270 2 0.2 15 4.53 7.35

5/4/2006 0.1717 0.1717 15.7 4.38 7.35

5/5/2006 0.1670 0.1670 200 288 2 0.2 15.6 4.99 7.4

5/6/2006 0.1578 0.1578

5/7/2006 0.1627 0.1627

5/8/2006 0.1692 0.1692 15.7 4.08 7.37

5/9/2006 0.1714 0.1714 15.6 4.4 7.37

5/10/2006 0.1589 0.1589 319 248 5 2.2 16.2 4.32 7.35

5/11/2006 0.1399 0.1399 16.9 4.62 7.38

5/12/2006 0.1449 0.1449 277 318 2 4.4 16.1 4.34 7.37

5/13/2006 0.1584 0.1584

5/14/2006 0.1572 0.1572

5/15/2006 0.151 0.151 18.2 3.98 7.41

5/16/2006 0.1443 0.1443 21.3 4.29 7.4

5/17/2006 0.1359 0.1359 269 152 6 7 22.5 4.28 7.44

5/18/2006 0.1381 0.1381 22.8 4.78 7.46

5/19/2006 0.1336 0.1336 298 130 4 4 21.7 4.2 7.46

5/20/2006 0.146 0.146

5/21/2006 0.1651 0.1651

5/22/2006 0.1934 0.1934 16.1 4.01 7.43

5/23/2006 0.191 0.191 18.1 2.4 7.51

5/24/2006 0.1998 0.1998 17.3 3.81 6.99

5/25/2006 0.2011 0.2011 18.6 4.31 7.37

5/26/2006 0.1971 0.1971 308 338 3 6 17.3 4.33 7.42

5/27/2006 0.201 0.201

5/28/2006 0.205 0.205

5/29/2006 0.2065 0.2065

5/30/2006 0.2253 0.2253 18.2 4.02 7.4

5/31/2006 0.2245 0.2245 312 325 4 1.4 18.3 4.25 7.38

6/1/2006 0.1947 0.1947 20.2 4.58 7.46

6/2/2006 0.1407 0.1407 304 284 2 0.2 19.4 3.8 7.43

6/3/2006 0.2003 0.2003

6/4/2006 0.1552 0.1552

6/5/2006 0.1758 0.1758 20.2 3.53 7.39

6/6/2006 0.1513 0.1513 20.8 4.11 7.45

6/7/2006 0.1511 0.1511 23.6 4.13 7.47

6/8/2006 0.1528 0.1528 20.8 3.6 7.48

6/9/2006 0.1491 0.1491 294 315 5 1 20.2 3.41 7.47

6/10/2006 0.1525 0.1525

6/11/2006 0.1544 0.1544

6/12/2006 0.1614 0.1614 21.9 3.65 7.4

6/13/2006 0.1676 0.1676 20.4 3.34 7.45

6/14/2006 0.1819 0.1819 267 288 2 0.2 20.3 3.51 7.48

6/15/2006 0.1743 0.1743 20.1 3.48 7.47

6/16/2006 0.1714 0.1714 211 242 2 1.4 20.5 3.45 7.47

6/17/2006 0.1643 0.1643

6/18/2006 0.1714 0.1714

6/19/2006 0.1619 0.1619 19.8 3.65 7.43

6/20/2006 0.1615 0.1615 19.6 3.74 7.5

6/21/2006 0.155 0.155 281 294 1 1.8 19.8 3.84 7.51

6/22/2006 0.1474 0.1474 19.9 4.56 7.39

6/23/2006 0.1478 0.1478 240 232 2 0.2 21 4.4 7.36

6/24/2006 0.1571 0.1571

6/25/2006 0.152 0.152

6/26/2006 0.1527 0.1527 23 4.44 7.36

6/27/2006 0.1601 0.1601 23.4 4.46 7.38

6/28/2006 0.1478 0.1478 22 4.2 7.38

6/29/2006 0.1432 0.1432 21.5 4 7.37

6/30/2006 0.1501 0.1501 333 204 2 0.2 21.2 3.91 7.37

7/1/2006 0.1592 0.1592

7/2/2006 0.1601 0.1601

7/3/2006 0.1585 0.1585

7/4/2006 0.1552 0.1552

7/5/2006 0.1434 0.1434 276 286 1.00 1.0 23.20 4.38 7.40

7/6/2006 0.1454 0.1454 22.50 3.66 7.42

7/7/2006 0.1409 0.1409 259 264 2.00 0.2 21.50 4.26 7.40

7/8/2006 0.1341 0.1341

7/9/2006 0.1369 0.1369

7/10/2006 0.1408 0.1408 22.80 4.74 7.34

7/11/2006 0.1404 0.1404 22.10 4.44 7.38

7/12/2006 0.1439 0.1439 271 306 2.00 6.0 21.70 4.28 7.38

7/13/2006 0.1406 0.1406 21.10 4.02 7.39

7/14/2006 0.1435 0.1435 288 300 1.00 4.0 21.10 6.14 7.40

7/15/2006 0.1411 0.1411

7/16/2006 0.1413 0.1413

7/17/2006 0.1432 0.1432 23.60 4.22 7.33

7/18/2006 0.1495 0.1495 21.60 4.13 7.36

7/19/2006 0.1391 0.1391 174 146 1.00 3.0 21.50 5.20 7.36

7/20/2006 0.1445 0.1445 21.60 4.43 7.36

7/21/2006 0.1402 0.1402 258 285 1.00 0.4 22.20 4.48 7.37

7/22/2006 0.1392 0.1392

7/23/2006 0.1383 0.1383

7/24/2006 0.1514 0.1514 25.90 5.01 7.36

7/25/2006 0.1255 0.1255 24.30 5.40 7.41

7/26/2006 0.1312 0.1312 302 206 3.00 0.4 22.70 4.32 7.42

7/27/2006 0.1247 0.1247 23.60 4.19 7.39

7/28/2006 0.1268 0.1268 248 228 2.00 0.8 22.80 4.90 7.30

7/29/2006 0.1308 0.1308

7/30/2006 0.1329 0.1329 7.21

7/31/2006 0.1432 0.1432 20.70 5.20

8/1/2006 0.1389 0.1389 21.1 4.16 7.24

8/2/2006 0.1355 0.1355 202 292 1 0.2 21.1 4.10 7.23

8/3/2006 0.1293 0.1293 21.3 3.96 7.23

8/4/2006 0.1344 0.1344 21.3 4.03 7.23

8/5/2006 0.1270 0.1270

8/6/2006 0.1405 0.1405

8/7/2006 0.1532 0.1532 24.1 5.14 7.15

8/8/2006 0.1493 0.1493 23.0 4.30 7.20

8/9/2006 0.1424 0.1424 229 240 2 0.2 23.4 4.38 7.20

8/10/2006 0.1450 0.1450 22.1 4.15 7.22

8/11/2006 0.1385 0.1385 208 184 1 0.4 21.2 4.40 7.28

8/12/2006 0.1424 0.1424

8/13/2006 0.1520 0.1520

8/14/2006 0.1553 0.1553 23.2 4.72 7.30

8/15/2006 0.1554 0.1554 22.4 4.30 7.33

8/16/2006 0.1497 0.1497 228 202 2 0.4 21.6 4.36 7.36

8/17/2006 0.1413 0.1413 21.5 5.15 7.41

8/18/2006 0.1510 0.1510 181 270 1 1.2 20.9 3.91 7.32

8/19/2006 0.1476 0.1476

8/20/2006 0.1544 0.1544 23.2

8/21/2006 0.1526 0.1526 21.9 4.07 7.27

8/22/2006 0.1532 0.1532 21.4 3.50 7.32

8/23/2006 0.1463 0.1463 168 140 1 0.2 20.9 3.60 7.33

8/24/2006 0.1516 0.1516 20.4 4.00 7.35

8/25/2006 0.1462 0.1462 201 216 1 0.2 3.92 7.34

8/26/2006 0.1443 0.1443

8/27/2006 0.1588 0.1588

8/28/2006 0.1533 0.1533 23.1 4.72 7.32

8/29/2006 0.1601 0.1601 21.6 3.43 7.33

8/30/2006 0.1567 0.1567 20.3 3.32 7.32

8/31/2006 0.1593 0.1593 19.6 3.57 7.32

9/1/2006 0.1545 0.1545 160 172 1 1.4 19.7 3.61 7.33

9/2/2006 0.1552 0.1552

9/3/2006 0.1542 0.1542

9/4/2006 0.1610 0.1610

9/5/2006 0.1776 0.1776 19.8 4.57 7.36

9/6/2006 0.1580 0.1580 260 154 1 2 21.8 3.09 7.38

9/7/2006 0.1654 0.1654 21.9 4.54 7.39

9/8/2006 0.1607 0.1607 227 198 2 2.8 21.5 3.63 7.37

9/9/2006 0.1567 0.1567

9/10/2006 0.1720 0.1720

9/11/2006 0.1687 0.1687 4.23 7.37

9/12/2006 0.1624 0.1624 21.7 4.82 7.34

9/13/2006 0.1678 0.1678 229 166 1 2 22.0 3.53 7.34

9/14/2006 0.1646 0.1646 20.7 3.82 7.37

9/15/2006 0.1628 0.1628 172 254 2 1.4 19.5 3.99 7.39

9/16/2006 0.1661 0.1661 18.2

9/17/2006 0.1692 0.1692

9/18/2006 0.1864 0.1864 19.7 5.22 7.35

9/19/2006 0.1664 0.1664 19.3 3.71 7.38

9/20/2006 0.1604 0.1604 238 192 2 1.6 18.9 3.89 7.37

9/21/2006 0.1613 0.1613 18.8 3.56 7.35

9/22/2006 0.1644 0.1644 215 236 2 3.6 18.5 3.98 7.37

9/23/2006 0.1622 0.1622

9/24/2006 0.1658 0.1658

9/25/2006 0.1662 0.1662 18.8 4.45 7.39

9/26/2006 0.1570 0.1570 19.0 4.28 7.39

9/27/2006 0.1628 0.1628 276 218 2 0.6 19.5 4.33 7.35

9/28/2006 0.1580 0.1580 18.4 5.55 7.42

9/29/2006 0.1553 0.1553 230 208 2 0.8 19.1 5.20 7.36

9/30/2006 0.1537 0.1537

10/1/2006 0.1637 0.1637

10/2/2006 0.1737 0.1737 19.6 5.27 7.38

10/3/2006 0.1579 0.1579 18.7 4.46 7.36

10/4/2006 0.1568 0.1568 220 136 1 1.8 18.7 4.55 7.35

10/5/2006 0.1708 0.1708 18.5 4.34 7.34

10/6/2006 0.1633 0.1633 223 192 2 0.4 18.5 4.60 7.35

10/7/2006 0.1554 0.1554

10/8/2006 0.1709 0.1709

10/9/2006 0.1842 0.1842 25.9 4.39 7.39

10/10/2006 0.1711 0.1711 17.9 4.12 7.41

10/11/2006 0.1604 0.1604 244 240 3 0.2 16.6 4.79 7.40

10/12/2006 0.1530 0.1530 16.5 4.40 7.36

10/13/2006 0.1534 0.1534 202 158 1 0.2 17.2 5.10 7.37

10/14/2006 0.1492 0.1492

10/15/2006 0.1519 0.1519

10/16/2006 0.1942 0.1942 24.2 5.45 7.39

10/17/2006 0.1630 0.1630 23.8 5.99 7.39

10/18/2006 0.1620 0.1620 221 102 1 0.8 21.1 5.52 7.39

10/19/2006 0.1619 0.1619 27.5 4.65 7.37

10/20/2006 0.1640 0.1640 187 164 2 0.2 23.7 5.09 7.39

10/21/2006 0.1583 0.1583

10/22/2006 0.1644 0.1644

10/23/2006 0.1756 0.1756 25.0 5.02 7.47

10/24/2006 0.1547 0.1547 17.4 5.02 7.40

10/25/2006 0.1614 0.1614 166 176 2 0.2 25.6 5.10 7.43

10/26/2006 0.1601 0.1601 26.2 5.10 7.37

10/27/2006 0.1541 0.1541 268 132 2 0.2 28.6 5.82 7.42

10/28/2006 0.1426 0.1426

10/29/2006 0.1532 0.1532

10/30/2006 0.1659 0.1659 23.3 4.97 7.40

10/31/2006 0.1574 0.1574 22.2 5.51 7.36

11/1/2006 0.1551 0.1551 223 148 1 0.4 12.4 6.47 7.37

11/2/2006 0.1664 0.1664 14.2 5.71 7.41

11/3/2006 0.1683 0.1683 223 158 1 0.8 15.5 5.43 7.39

11/4/2006 0.1551 0.1551

11/5/2006 0.1402 0.1402

11/6/2006 0.1505 0.1505 26.0 3.96 7.33

11/7/2006 0.1186 0.1186 18.5 5.30 7.32

11/8/2006 0.1251 0.1251 164 250 2 0.2 16.6 4.07 7.35

11/9/2006 0.1707 0.1707 17.3 4.54 7.38

11/10/2006 0.1896 0.1896

11/11/2006 0.1818 0.1818

11/12/2006 0.1794 0.1794

11/13/2006 0.1834 0.1834 24.9 4.39 7.39

11/14/2006 0.1642 0.1642 15.4 4.77 7.36

11/15/2006 0.1708 0.1708 196 146 1 1.4 15.3 4.66 7.31

11/16/2006 0.1705 0.1705 15.5 4.30 7.29

11/17/2006 0.1739 0.1739 196 168 2 5.6 15.3 5.03 7.34

11/18/2006 0.1671 0.1671

11/19/2006 0.1775 0.1775

11/20/2006 0.1809 0.1809 27.2 4.23 7.30

11/21/2006 0.1695 0.1695 14.5 4.77 7.29

11/22/2006 0.1666 0.1666 221 146 5 2.2 14.7 4.68 7.29

11/23/2006 0.1741 0.1741

11/24/2006 0.1846 0.1846

11/25/2006 0.1659 0.1659

11/26/2006 0.1773 0.1773

11/27/2006 0.1879 0.1879 12.4 5.07 7.28

11/28/2006 0.1708 0.1708 11.5 5.31 7.27

11/29/2006 0.1687 0.1687 223 192 4 11.3 4.82 7.17

11/30/2006 0.1654 0.1654 1 10.8 5.49 7.23

12/1/2006 0.1694 0.1694 10.5 5.60 7.21

12/2/2006 0.1587 0.1587

12/3/2006 0.1792 0.1792

12/4/2006 0.1790 0.1790 23.1 5.44 7.19

12/5/2006 0.1698 0.1698 11.9 4.86 7.14

12/6/2006 0.1687 0.1687 259 344 5 6 26.8 5.10 7.23

12/7/2006 0.1678 0.1678 24.1 5.98 7.20

12/8/2006 0.1691 0.1691 319 260 2 7 27.3 4.67 7.12

12/9/2006 0.1679 0.1679

12/10/2006 0.1766 0.1766

12/11/2006 0.1909 0.1909 25.2 5.57 7.22

12/12/2006 0.1707 0.1707 13.3 5.35 7.20

12/13/2006 0.1623 0.1623 238 140 2 0.8 14.2 5.60 7.20

12/14/2006 0.1571 0.1571 24.4 7.65 7.26

12/15/2006 0.1571 0.1571 12.3 5.08 7.18

12/16/2006 0.1988 0.1988

12/17/2006 0.1613 0.1613

12/18/2006 0.1656 0.1656 23.4 5.37 7.16

12/19/2006 0.1657 0.1657 11.1 5.99 7.12

12/20/2006 0.1697 0.1697 270 200 1 2 12.0 6.72 7.13

12/21/2006 0.1580 0.1580 26.1 6.67 7.16

12/22/2006 0.1520 0.1520 203 166 1 3 11.4 6.18 7.11

12/23/2006 0.1632 0.1632

12/24/2006 0.1656 0.1656

12/25/2006 0.1727 0.1727

12/26/2006 0.1599 0.1599 26.6 5.83 7.09

12/27/2006 0.1880 0.1880 308 100 6 1 12.9 6.01 7.07

12/28/2006 0.1753 0.1753 12.1 6.16 7.11

12/29/2006 0.1599 0.1599 219 178 3 0.2 11.0 6.20 7.09

12/30/2006 0.1516 0.1516

12/31/2006 0.1628 0.1628

1/1/2007 0.1732 0.1732

1/2/2007 0.1710 0.1710 12.4 5.03 7.07

1/3/2007 0.1425 0.1425 202 252 3 4 11.6 6.13 7.09

1/4/2007 0.1652 0.1652 11.9 4.77 6.84

1/5/2007 0.1631 0.1631 197 152 6 1.6 5.47 6.80

1/6/2007 0.1605 0.1605 5.47 6.80

1/7/2007 0.1445 0.1445 12.5

1/8/2007 0.1325 0.1325 12.6 6.20 7.07

1/9/2007 0.1104 0.1104 12.1 6.17 7.05

1/10/2007 0.1160 0.1160 427 802 4 8 10.5 6.14 7.07

1/11/2007 0.1063 0.1063 10.3 7.04 7.10

1/12/2007 0.1009 0.1009 292 244 3 4 7.22 7.17

1/13/2007 0.1089 0.1089 7.17

1/14/2007 0.1147 0.1147

1/15/2007 0.1032 0.1032 10.2

1/16/2007 0.1175 0.1175 8.7 6.89 7.09

1/17/2007 0.1112 0.1112 354 168 4 2 9.5 7.04 7.07

1/18/2007 0.1188 0.1188 9.3 5.91 7.02

1/19/2007 0.1089 0.1089 313 300 4 6 6.65 7.10

1/20/2007 0.1100 0.1100

1/21/2007 0.1143 0.1143 11.9

1/22/2007 0.1178 0.1178 14.9 6.20 7.08

1/23/2007 0.1072 0.1072 11.6 6.23 7.06

1/24/2007 0.1110 0.1110 383 360 4 9 10.9 5.95 7.05

1/25/2007 0.1094 0.1094 11.0 5.86 7.03

1/26/2007 0.1026 0.1026 286 224 3 2 6.83 7.09

1/27/2007 0.1187 0.1187

1/28/2007 0.1921 0.1921

1/29/2007 0.1064 0.1064 11.9 6.08 6.95

1/30/2007 0.1075 0.1075 12.1 6.02 6.91

1/31/2007 0.1135 0.1135 348 240 3 1.7 10.8 5.67 6.85

2/1/2007 0.1023 0.1023 10.5 5.58 6.83

2/2/2007 0.1056 0.1056 355 244 4 1 9.8 5.90 6.81

2/3/2007 0.1002 0.1002

2/4/2007 0.1127 0.1127

2/5/2007 0.1172 0.1172 12.2 5.52 6.79

2/6/2007 0.1140 0.1140 10.2 5.91 6.79

2/7/2007 0.1029 0.1029 378 298 4 2 11.8 5.35 6.80

2/8/2007 0.1214 0.1214 14.9 4.33 6.74

2/9/2007 0.1097 0.1097 313 260 4 1 12.7 4.71 6.78

2/10/2007 0.1159 0.1159

2/11/2007 0.1215 0.1215

2/12/2007 0.1926 0.1926 13.8 4.80 6.83

2/13/2007 0.1757 0.1757 11.2 4.86 6.81

2/14/2007 0.1101 0.1101 513 344 4 4 12.7 4.80 6.86

2/15/2007 0.1102 0.1102 12.0 5.03 6.85

2/16/2007 0.1764 0.1764 344 230 3 6 13.1 3.51 6.86

2/17/2007 0.1910 0.1910

2/18/2007 0.1913 0.1913

2/19/2007 0.1069 0.1069

2/20/2007 0.1147 0.1147 13.0 5.17 6.91

2/21/2007 0.1043 0.1043 355 164 5 2 12.0 5.45 6.94

2/22/2007 0.1062 0.1062 12.1 4.75 6.91

2/23/2007 0.1856 0.1856 408 784 6 11 11.5 5.01 6.94

2/24/2007 0.1862 0.1862

2/25/2007 0.1034 0.1034

2/26/2007 0.1284 0.1284 13.5 5.21 6.93

2/27/2007 0.1081 0.1081 12.4 4.36 6.88

2/28/2007 0.1071 0.1071 386 108 9 2 12.3 4.61 6.89

3/1/2007 0.1044 0.1044 11.7

3/2/2007 0.1049 0.1049 10.6 5.09 6.89

3/3/2007 0.1983 0.1983 328 162 7 3 5.25 6.87

3/4/2007 0.1216 0.1216

3/5/2007 0.1087 0.1087 14.2 5.27 6.92

3/6/2007 0.1900 0.1900 13.3 8.68 6.87

3/7/2007 0.1979 0.1979 407 280 5 5 13.9 4.58 6.88

3/8/2007 0.1090 0.1090 12.7 4.65 6.84

3/9/2007 0.1165 0.1165 380 270 4 4 13.4 4.65 6.86

3/10/2007 0.1989 0.1989

3/11/2007 0.1068 0.1068

3/12/2007 0.1822 0.1822 16.1 3.77 6.90

3/13/2007 0.2039 0.2039 15.4 4.57 6.95

3/14/2007 0.1049 0.1049 312 140 4 2 13.0 4.26 6.90

3/15/2007 0.1800 0.1800 12.7 4.78 6.90

3/16/2007 0.1046 0.1046 276 158 3 4 13.9 4.74 6.92

3/17/2007 0.2474 0.2474

3/18/2007 0.2699 0.2699

3/19/2007 0.2519 0.2519 16.2 5.60 6.99

3/20/2007 0.1811 0.1811 15.8 5.67 6.98

3/21/2007 0.1108 0.1108 303 172 5 5 12.5 5.08 6.91

3/22/2007 0.1930 0.1930 13.6 4.93 6.94

3/23/2007 0.1948 0.1948 292 140 3 2 14.6 7.17 7.00

3/24/2007 0.1585 0.1585

3/25/2007 0.1530 0.1530

3/26/2007 0.1077 0.1077 14.6 6.33 7.13

3/27/2007 0.1063 0.1063 14.1 6.26 7.17

3/28/2007 0.1039 0.1039 337 236 2 3 13.5 5.71 7.20

3/29/2007 0.1976 0.1976 14.1 5.06 7.18

3/30/2007 0.1886 0.1886 317 192 1 0.6 14.2 5.28 7.18

3/31/2007

4/1/2007 0.1018 0.1018

4/2/2007 0.1938 0.1938 14.6 5.68 7.37

4/3/2007 0.1983 0.1983 14.5 5.50 7.35

4/4/2007 0.1813 0.1813 14.0 5.54 7.20

4/5/2007 0.1010 0.1010 205 180 3 2 15.0 5.45 7.16

4/6/2007 0.1843 0.1843 239 204 3 3 14.9 4.91

4/7/2007 0.1982 0.1982

4/8/2007 0.1907 0.1907

4/9/2007 0.1139 0.1139 14.9 4.00 7.26

4/10/2007 0.1150 0.1150 13.3 4.50 7.28

4/11/2007 0.1910 0.1910 315 334 5 4 13.7 4.62 7.22

4/12/2007 0.2336 0.2336 14.1 4.59 7.21

4/13/2007 0.1443 0.1443 311 268 3 0.2 14.8 5.13 7.18

4/14/2007 0.2973 0.2973

4/15/2007 0.1799 0.1799

4/16/2007 0.1979 0.1979 15.0 3.76 7.11

4/17/2007 0.2333 0.2333 15.3 5.05 7.08

4/18/2007 0.2504 0.2504 342 218 3 3 15.0 4.51 7.05

4/19/2007 0.2330 0.2330 14.9 4.51 7.05

4/20/2007 0.1126 0.1126 283 164 2 0.2 13.9 4.27 7.06

4/21/2007 0.3179 0.3179

4/22/2007 0.1045 0.1045

4/23/2007 0.1849 0.1849 16.4 3.92 7.17

4/24/2007 0.1177 0.1177 16.7 4.05 7.16

4/25/2007 0.1200 0.1200 427 170 3 0.2 16.7 3.57 7.18

4/26/2007 0.1120 0.1120 16.4 3.82 7.16

4/27/2007 0.1095 0.1095 303 204 2 1.2 16.4 3.81 7.16

4/28/2007 0.1066 0.1066

4/29/2007 0.1166 0.1166

4/30/2007 0.1158 0.1158 17.3 4.23 7.19

5/1/2007 0.1020 0.1020 17.6 3.89 7.17

5/2/2007 0.1091 0.1091 330 400 3 0.4 17.0 3.77 7.15

5/3/2007 0.1097 0.1097 15.8 3.98 7.17

5/4/2007 0.1127 0.1127 250 194 1 0.6 15.0 4.51 7.20

5/5/2007 0.1143 0.1143

5/6/2007 0.1166 0.1166

5/7/2007 0.1175 0.1175 18.3 4.76 7.22

5/8/2007 0.1333 0.1333 18.6 4.13 7.20

5/9/2007 0.1202 0.1202 372 194 2 1.8 18.3 4.14 7.21

5/10/2007 0.1169 0.1169 18.1 3.86 7.22

5/11/2007 0.1078 0.1078 282 258 1 1.4 17.8 3.86 7.24

5/12/2007 0.1086 0.1086

5/13/2007 0.1797 0.1797

5/14/2007 0.1628 0.1628 17.9 4.08 7.26

5/15/2007 0.1052 0.1052 17.8 4.24 7.25

5/16/2007 0.1098 0.1098 308 276 2 3.0 18.8 3.99 7.26

5/17/2007 0.1137 0.1137 18.7 3.61 7.25

5/18/2007 0.1036 0.1036 313 184 1 0.2 17.9 3.87 7.26

5/19/2007 0.2763 0.2763

5/20/2007 0.1984 0.1984

5/21/2007 0.1101 0.1101 18.7 4.37 7.27

5/22/2007 0.1181 0.1181 16.9 3.94 7.24

5/23/2007 0.1965 0.1965 17.5 3.86 7.24

5/24/2007 0.2142 0.2142 17.6 3.88 7.24

5/25/2007 0.1822 0.1822 320 280 2 1.0 17.6 3.81 7.23

5/26/2007 0.2065 0.2065

5/27/2007 0.1610 0.1610

5/28/2007 0.2334 0.2334

5/29/2007 0.1213 0.1213 18.8 3.93 7.27

5/30/2007 0.1974 0.1974 303 314 2 0.6 18.8 3.69 7.22

5/31/2007 0.1061 0.1061 19.8 3.55 7.24

6/1/2007 0.1839 0.1839 299 234 2 2.4 19.7 3.54 7.24

6/2/2007 0.1091 0.1091

6/3/2007 0.1236 0.1236

6/4/2007 0.1097 0.1097 22.1 3.57 7.35

6/5/2007 0.1997 0.1997 20.7 3.34 7.27

6/6/2007 0.1095 0.1095 327 306 2 1.2 19.1 4.16 7.27

6/7/2007 0.1059 0.1059 18.9 3.90 7.25

6/8/2007 0.2133 0.2133 317 210 1 0.4 18.9 3.53 7.24

6/9/2007 0.1070 0.1070

6/10/2007 0.1909 0.1909

6/11/2007 0.1054 0.1054 19.1 4.22 7.27

6/12/2007 0.1140 0.1140 18.7 3.79 7.24

6/13/2007 0.1017 0.1017 293 278 2 1.2 19.1 3.58 7.24

6/14/2007 0.1510 0.1510 18.8 3.61 7.24

6/15/2007 0.1748 0.1748 354 184 2 3.8 19.4 3.69 7.22

6/16/2007 0.2110 0.2110

6/17/2007 0.3463 0.3463

6/18/2007 0.1131 0.1131 19.5 3.95 7.27

6/19/2007 0.1167 0.1167 20.3 4.12 7.24

6/20/2007 0.1130 0.1130 364 486 6 0.2 20.8 3.90 7.24

6/21/2007 0.1107 0.1107 20.7 3.74 7.24

6/22/2007 0.1865 0.1865 292 166 2 2 20.1 3.71 7.25

6/23/2007 0.1141 0.1141

6/24/2007 0.1054 0.1054

6/25/2007 0.1204 0.1204 19.1 4.46 7.24

6/26/2007 0.1124 0.1124 19.0 4.45 7.26

6/27/2007 0.2097 0.2097 303 234 3 3 19.5 3.74 7.26

6/28/2007 0.1250 0.1250 22.0 4.45 7.25

6/29/2007 0.1369 0.1369 20.5 3.08 7.21

6/30/2007 0.1300 0.1300

7/1/2007 0.1070 0.1070

7/2/2007 0.2005 0.2005 20.4 3.75 7.29

7/3/2007 0.2768 0.2768 21.9 4.12 7.33

7/4/2007 0.1092 0.1092

7/5/2007 0.1117 0.1117 22.0 4.20 7.26

7/6/2007 0.1127 0.1127 286 304 2 0.6 22.5 3.92 7.25

7/7/2007 0.1021 0.1021

7/8/2007 0.1973 0.1973

7/9/2007 0.1840 0.1840 22.1 4.65 7.28

7/10/2007 0.2106 0.2106 22.0 5.92 7.91

7/11/2007 0.1991 0.1991 304 322 1 1.6 22.8 5.99 7.39

7/12/2007 0.1168 0.1168 22.0 4.10 7.25

7/13/2007 0.1047 0.1047 22.3 4.19 7.25

7/14/2007 0.1142 0.1142

7/15/2007 0.2381 0.2381

7/16/2007 0.2376 0.2376 22.5 4.92 7.30

7/17/2007 0.1107 0.1107 21.3 3.90 7.67

7/18/2007 0.1630 0.1630 403 566 1 1.2 21.6 3.85 7.25

7/19/2007 0.1880 0.1880 21.0 3.88 7.22

7/20/2007 0.1074 0.1074 272 294 2 2.0 20.9 3.60 7.21

7/21/2007 0.2104 0.2104

7/22/2007 0.1065 0.1065

7/23/2007 0.1690 0.1690 23.9 5.17 7.28

7/24/2007 21.8 4.15 7.26

7/25/2007 0.1683 0.1683 288 240 1 0.2 20.8 4.66 7.27

7/26/2007 0.1051 0.1051 21.0 3.85 7.22

7/27/2007 0.1044 0.1044 260 242 2 1 21.5 5.23 7.34

7/28/2007 0.1950 0.1950

7/29/2007 0.1075 0.1075

7/30/2007 0.1004 0.1004 21.5 6.19 7.40

7/31/2007 0.1045 0.1045 20.4 5.24 7.29

8/1/2007 0.1843 0.1843 273 308 1 0.2 20.4 4.52 7.27

8/2/2007 0.1550 0.1550 22.0 4.60 7.30

8/3/2007 0.1005 0.1005 236 280 2 0.2 21.4 4.13 7.23

8/4/2007 0.1922 0.1922

8/5/2007 0.1025 0.1025

8/6/2007 0.1020 0.1020 21.9 4.68 7.34

8/7/2007 0.1137 0.1137 21.8 4.28 7.18

8/8/2007 0.1554 0.1554 300 294 3 0.6 21.0 4.36 7.18

8/9/2007 0.1873 0.1873 21.0 4.37 7.16

8/10/2007 0.1675 0.1675 309 310 2 0.8 20.4 3.58 7.17

8/11/2007 0.2057 0.2057

8/12/2007 0.2053 0.2053

8/13/2007 0.1683 0.1683 20.1 3.40 7.15

8/14/2007 0.1713 0.1713 20.7 4.06 7.14

8/15/2007 0.1365 0.1365 332 246 3 2 12.1 4.20 7.14

8/16/2007 0.1126 0.1126 21.8 4.18 7.11

8/17/2007 0.2181 0.2181 245 296 2 2 21.5 3.98 7.15

8/18/2007 0.1082 0.1082

8/19/2007 0.1949 0.1949

8/20/2007 0.1760 0.1760 21.7 4.30 7.24

8/21/2007 0.1040 0.1040 20.4 4.02 7.22

8/22/2007 0.1002 0.1002 306 316 3 4 21.5 4.20 7.27

8/23/2007 0.1041 0.1041 21.3 4.14 7.28

8/24/2007 0.1895 0.1895 266 166 2 3 21.1 3.86 7.29

8/25/2007 0.1105 0.1105

8/26/2007 0.1196 0.1196

8/27/2007 0.1288 0.1288 20.5 4.33 7.35

8/28/2007 0.1163 0.1163 19.9 4.25 7.27

8/29/2007 0.1084 0.1084 293 332 1 1 20.1 4.40 7.29

8/30/2007 0.1129 0.1129 21.0 4.32 7.28

8/31/2007 0.1037 0.1037 307 222 1 4 22.5 3.90 7.24

9/1/2007 0.0142 0.0142

9/2/2007 0.2433 0.2433

9/3/2007 0.1478 0.1478

9/4/2007 0.1297 0.1297 21.8 4.00 7.22

9/5/2007 0.1889 0.1889 337 158 2 1 21.7 4.05 7.23

9/6/2007 0.1023 0.1023 20.9 4.13 7.23

9/7/2007 0.1553 0.1553 220 252 1 2 20.4 4.13 7.22

9/8/2007 0.1095 0.1095

9/9/2007 0.1152 0.1152

9/10/2007 0.1267 0.1267 19.9 4.05 7.15

9/11/2007 0.1116 0.1116 19.3 4.21 7.13

9/12/2007 0.1101 0.1101 317 360 2 4 20.3 4.10 7.12

9/13/2007 0.1008 0.1008 20.1 4.30 7.17

9/14/2007 0.1716 0.1716 299 188 2 3 20.4 4.07 7.11

9/15/2007 0.2325 0.2325

9/16/2007 0.2774 0.2774

9/17/2007 0.1134 0.1134 20.3 4.29 7.11

9/18/2007 0.2343 0.2343 18.7 4.16 7.12

9/19/2007 0.2901 0.2901 306 260 2 2 18.7 4.44 7.14

9/20/2007 0.1167 0.1167 18.3 4.45 7.11

9/21/2007 0.1063 0.1063 300 206 2 1 18.3 4.62 7.13

9/22/2007 0.1001 0.1001

9/23/2007 0.11 0.11

9/24/2007 0.1204 0.1204 19.1 5.58 7.28

9/25/2007 0.1083 0.1083 17.7 4.50 7.2

9/26/2007 0.1973 0.1973 317 286 2 0.4 18.2 5.11 7.23

9/27/2007 0.103 0.103 19.6 5.18 7.27

9/28/2007 0.1001 0.1001 332 190 1 1 4.81 7.19

9/29/2007 0.173 0.173

9/30/2007 0.1047 0.1047

10/1/2007 0.1108 18.4 5.67 7.13

10/2/2007 0.1850 18.3 6.72 7.11

10/3/2007 0.1638 287 176 2.81 4.8 17.8 5.07 6.94

10/4/2007 0.1040 17.6 4.66 6.95

10/5/2007 0.1068 372 244 1 1.8 17.1 4.98 6.95

10/6/2007 0.1103

10/7/2007 0.2028

10/8/2007 0.1110 17.9 4.58 6.99

10/9/2007 0.1907 18.1 5.27 7.05

10/10/2007 0.1927 314 194 1.9 0.8 19.4 5.1 6.94

10/11/2007 0.1609 17.4 6.42 7.05

10/12/2007 0.8245 369 206 1.9 1.4 17.5 5.52 7.06

10/13/2007 0.6843

10/14/2007 0.9557

10/15/2007 0.1234 18 5.62 6.97

10/16/2007 0.8865 17.8 5.87 7.00

10/17/2007 0.7519 274 326 1 0.4 17.2 5.3 6.86

10/18/2007 0.1047 16.8 6.11 7.05

10/19/2007 0.6379 381 170 1 1 17.1 5.85 6.97

10/20/2007 0.2745

10/21/2007 0.4209

10/22/2007 0.7763 17.2 6.1 6.93

10/23/2007 0.8806 16.9 5.84 6.93

10/24/2007 0.9625 285 214 1 2.2 16.7 5.47 6.89

10/25/2007 0.1039 16.68 5.23 6.88

10/26/2007 0.1186 298 180 1 2.6 15.5 4.92 6.94

10/27/2007 0.1064

10/28/2007 0.1100

10/29/2007 0.1067 14.92 5.08 6.83

10/30/2007 0.7803 14.93 5.83 6.88

10/31/2007 0.9197 295 192 1.5 4 14.22 5.67 6.92

11/1/2007 0.6319 14.4 5.62 6.94

11/2/2007 0.9046 316 232 2 4 13.95 6.37 6.93

11/3/2007 0.7130

11/4/2007 0.7170

11/5/2007 0.7267 14.3 5.7 6.92

11/6/2007 0.9105 15.01 6.1 7.00

11/7/2007 0.9161 509 270 0.78 1.8 14.9 6.1 6.93

11/8/2007 0.7782 14.6 5.8 6.93

11/9/2007 0.7338 417 192 1.6 1.6 14.6 6.4 7.00

11/10/2007 0.1000

11/11/2007 0.3098

11/12/2007 0.1027 14.8 5.8 7.08

11/13/2007 0.7842 14.9 6.28 6.98

11/14/2007 0.1046 293 152 2.2 3 13.9 6.06 6.94

11/15/2007 0.1048 14.5 7.22 6.99

11/16/2007 0.4748 379 214 5 2.6 14.7 6.06 6.97

11/17/2007 0.2995

11/18/2007 0.1700

11/19/2007 0.7430 14.5 5.66 6.93

11/20/2007 0.2016 14.4 4.91 6.95

11/21/2007 0.1152 325 222 3 3 12.9 5.92 6.92

11/22/2007 0.9648

11/23/2007 0.1861

11/24/2007 0.1209

11/25/2007 0.1282

11/26/2007 0.1327 6.7 6.97

11/27/2007 0.1331 5.28 6.88

11/28/2007 0.1584 483 384 3 2 11.4 6.08 6.93

11/29/2007 0.1005 6.74 6.96

11/30/2007 0.2520 257 170 3 0.6 12.4 5.45 6.91

12/1/2007 0.4136

12/2/2007 0.1344

12/3/2007 0.1344 13.8 2.34 7.66

12/4/2007 0.21 14.6 6.39 7.02

12/5/2007 0.501 224 126 2 2 13.5 5.32 6.91

12/6/2007 0.4369 13.4 4.79 6.84

12/7/2007 0.2146 228 230 2 4 13.5 4.18 6.8

12/8/2007 0.3708

12/9/2007 0.1024

12/10/2007 0.1446 12 5.7 6.91

12/11/2007 0.1331 12.3 7.23 6.99

12/12/2007 0.1382 332 218 2 3 11.5 5.83 6.85

12/13/2007 0.1214 10.9 5.38 6.92

12/14/2007 0.1314 378 228 3 4 11.1 5.44 6.85

12/15/2007 0.122

12/16/2007 0.4333

12/17/2007 0.7463 12.4 6.66 6.96

12/18/2007 0.3925 12.6 7.07 6.99

12/19/2007 0.6591 13.1 5.62 6.89

12/20/2007 0.624 11.9 4.99 6.91

12/21/2007 0.1056 247 228 9 4 11.9 5.03 6.84

12/22/2007 0.12

12/23/2007 0.1307

12/24/2007 0.1632

12/25/2007 0.1464

12/26/2007 0.1108 12.1 5.93 6.87

12/27/2007 0.1584 12.2 6.73 6.94

12/28/2007 0.18 333 262 10 12 11.9 4.39 6.79

12/29/2007 0.4402

12/30/2007 0.4022

12/31/2007 0.1069 11.4 6.73 6.9

1/1/2008 0.124 0.124

1/2/2008 0.1224 0.1224 237 226 11 16 5.2 6.84

1/3/2008 0.1304 0.1304 4.6 6.78

1/4/2008 0.1276 0.1276 232 270 9 20 4.16 6.84

1/5/2008 0.421 0.421

1/6/2008 0.4009 0.4009

1/7/2008 0.1218 0.1218 3.8 6.85

1/8/2008 0.1079 0.1079 4.69 6.84

1/9/2008 0.1416 0.1416 227 608 9 16 4.85 6.83

1/10/2008 0.2721 0.2721 6.2 6.87

1/11/2008 0.108 0.108 213 278 10 18 4.25 6.82

1/12/2008 0.11 0.11

1/13/2008 0.1176 0.1176

1/14/2008 0.1488 0.1488 3.78 6.91

1/15/2008 0.1128 0.1128 5.62 6.86

1/16/2008 0.1704 0.1704 5.79 6.83

1/17/2008 0.1824 0.1824 229 182 11 17 5.56 6.79

1/18/2008 0.1824 0.1824 225 250 12 39 4.65 6.76

1/19/2008 0.1045 0.1045

1/20/2008 0.105 0.105

1/21/2008 0.1478 0.1478

1/22/2008 0.204 0.204 5.44 6.8

1/23/2008 0.1512 0.1512 235 192 13 25 6.66 6.84

1/24/2008 0.1872 0.1872 5.73 6.81

1/25/2008 0.18 0.18 331 224 11 24 5.04 6.92

1/26/2008 0.1776 0.1776

1/27/2008 0.2184 0.2184

1/28/2008 0.1584 0.1584 5.78 6.81

1/29/2008 0.1584 0.1584 5.49 6.81

1/30/2008 0.1152 0.1152 266 172 10 20 5.02 6.81

1/31/2008 0.0624 0.0624 6.03 6.85

2/1/2008 0.1606 0.1606 190 158 8 13 10 4.17 6.82

2/2/2008 0.1480 0.1480

2/3/2008 0.1130 0.1130

2/4/2008 0.1104 0.1104 11.9 4.69 6.78

2/5/2008 0.1368 0.1368 10.9 4.24 6.79

2/6/2008 0.1080 0.1080 234 196 12 7 10.7 4.17 6.74

2/7/2008 0.3642 0.3642 10.9 4.45 6.74

2/8/2008 0.1800 0.1800 324 226 12 12 12 4.09 6.72

2/9/2008 0.4070 0.4070

2/10/2008 0.1254 0.1254

2/11/2008 0.1920 0.1920 13.4 4.61 6.79

2/12/2008 0.2557 0.2557 12 4.61 6.77

2/13/2008 0.1464 0.1464 11.2 5.26 6.83

2/14/2008 0.1272 0.1272 11.1 4.28 6.82

2/15/2008 0.1248 0.1248 218 146 10 10 11.3 4.26 6.77

2/16/2008 0.1008 0.1008

2/17/2008 0.1032 0.1032

2/18/2008 0.1176 0.1176

2/19/2008 0.1272 0.1272 11.9 4.15 6.75

2/20/2008 0.1248 0.1248 223 138 12 38 11.9 4.33 6.77

2/21/2008 0.1056 0.1056 11.7 4.41 6.8

2/22/2008 0.1344 0.1344 284 264 12 24 11.3 4.2 6.79

2/23/2008 0.2045 0.2045

2/24/2008 0.1804 0.1804

2/25/2008 0.1025 0.1025 13.4 4.56 6.85

2/26/2008 0.2016 0.2016 12.6 4.73 6.85

2/27/2008 0.1176 0.1176 119 624 15 11 12.8 4.44 6.8

2/28/2008 0.2391 0.2391 12.7 4.83 6.81

2/29/2008 0.1072 0.1072 275 202 14 45 12.9 4.14 6.75

3/1/2008 0.1534 0.1534

3/2/2008 0.0124 0.0124

3/3/2008 0.012 0.012

3/4/2008 0.1176 0.1176

3/5/2008 0.1272 0.1272

3/6/2008 0.1488 0.1488

3/7/2008 0.1344 0.1344

3/8/2008 0.1032 0.1032

3/9/2008 0.1056 0.1056

3/10/2008 0.1368 0.1368

3/11/2008 0.1056 0.1056

3/12/2008 0.1224 0.1224

3/13/2008 0.144 0.144

3/14/2008 0.145 0.145

3/15/2008 0.1931 0.1931

3/16/2008 0.4731 0.4731

3/17/2008 0.1152 0.1152

3/18/2008 0.1392 0.1392

3/19/2008 0.108 0.108

3/20/2008 0.1464 0.1464

3/21/2008 0.1512 0.1512

3/22/2008 0.1584 0.1584

3/23/2008 0.1992 0.1992

3/24/2008 0.1968 0.1968

3/25/2008 0.18 0.18

3/26/2008 0.1536 0.1536

3/27/2008 0.1536 0.1536

3/28/2008 0.1632 0.1632

3/29/2008 0.1533 0.1533

3/30/2008 0.18 0.18

3/31/2008 0.1248 0.1248

4/1/2008 0.1464 0.1464 12.6 3.20 7.32

4/2/2008 0.1416 0.1416 294 172 13 16 12.8 3.19 7.06

4/3/2008 0.1416 0.1416 13.3 3.25 7.22

4/4/2008 0.1536 0.1536 272 236 13 1 14.4 4.17 7.1

4/5/2008 0.1344 0.1344

4/6/2008 0.1296 0.1296

4/7/2008 0.132 0.132 14.9 3.28 7.09

4/8/2008 0.1368 0.1368 14 3.22 7.12

4/9/2008 0.12 0.12 465 612 14 6 13.1 4.23 7.16

4/10/2008 0.1344 0.1344 14.4 3.78 7.21

4/11/2008 0.1392 0.1392 264 214 9 5 14.8 4.51 7.17

4/12/2008 0.144 0.144

4/13/2008 0.1632 0.1632

4/14/2008 0.1704 0.1704 16.4 3.08 7.08

4/15/2008 0.1344 0.1344 14.6 3.21 7.13

4/16/2008 0.1488 0.1488 350 136 9 5 14.2 4.10 7.14

4/17/2008 0.1488 0.1488 15.1 4.13 7.21

4/18/2008 0.144 0.144 257 214 10 5 15.2 4.30 7.16

4/19/2008 0.1368 0.1368

4/20/2008 0.1488 0.1488

4/21/2008 0.156 0.156 13 4.17 7.1

4/22/2008 0.1224 0.1224 13.5 4.46 7.12

4/23/2008 0.1296 0.1296 301 208 9 2 14.6 4.90 7.17

4/24/2008 0.12 0.12 14.8 4.37 7.12

4/25/2008 0.1296 0.1296

4/26/2008 0.1272 0.1272

4/27/2008 0.1464 0.1464

4/28/2008 0.1632 0.1632 16.5 4.46 7.12

4/29/2008 0.1368 0.1368 16 4.05 7.17

4/30/2008 0.1152 0.1152 288 186 4 0.8 15.7 5.82 7.26

5/1/2008 0.1392 0.1392 14.7 5.71 7.24

5/2/2008 0.1296 0.1296 228 192 3 1 14.9 4.3 7.16

5/3/2008 0.1248 0.1248

5/4/2008 0.13 0.13

5/5/2008 0.1224 0.1224 17.2 4.78 7.16

5/6/2008 0.1392 0.1392 17.7 4.98 7.24

5/7/2008 0.1224 0.1224 274 182 3 3 17.2 5.21 7.22

5/8/2008 0.1296 0.1296 16.7 4.93 7.2

5/9/2008 0.12 0.12 319 246 3 2 16.5 4.29 7.2

5/10/2008 0.1348 0.1348

5/11/2008 0.1258 0.1258

5/12/2008 0.1248 0.1248 16.5 4.71 7.27

5/13/2008 0.144 0.144 17.3 4.07 7.22

5/14/2008 0.1032 0.1032 333 232 6 2 17.4 5.02 7.28

5/15/2008 0.1416 0.1416 18.3 5.25 7.3

5/16/2008 0.1005 0.1005 280 310 7 5 19.3 4.1 7.23

5/17/2008 0.1536 0.1536

5/18/2008 0.1872 0.1872

5/19/2008 0.2064 0.2064 20.4 7.05 7.51

5/20/2008 0.1728 0.1728 20.3 3.89 7.29

5/21/2008 0.1344 0.1344 18.1 5.33 7.34

5/22/2008 0.1296 0.1296 17.6 4.76 7.25

5/23/2008 0.132 0.132 246 274 4 2 17.5 4.2 7.24

5/24/2008 0.1392 0.1392

5/25/2008 0.144 0.144

5/26/2008 0.12 0.12

5/27/2008 0.1704 0.1704 20.4 4.89 7.32

5/28/2008 0.1032 0.1032 261 212 3 1 19.9 4.54 7.31

5/29/2008 0.13 0.13 19.9 5.1 7.42

5/30/2008 0.1296 0.1296 281 244 3 1 19.8 4.89 7.43

5/31/2008 0.1488 0.1488

6/1/2008 0.132 0.132

6/2/2008 0.1680 0.1680 19 5.18 7.36

6/3/2008 0.1176 0.1176 18.8 5.17 7.32

6/4/2008 0.12 0.12 263 202 3 3 18 6.84 7.48

6/5/2008 0.1344 0.1344 18.6 4.79 7.28

6/6/2008 0.1080 0.1080 17.4 4.84 7.25

6/7/2008 0.1142 0.1142

6/8/2008 0.1405 0.1405

6/9/2008 0.168 0.168 19.1 3.52 7.17

6/10/2008 0.12 0.12 17.8 3.7 7.2

6/11/2008 0.1248 0.1248 259 324 5 0.6 17.7 4.84 7.26

6/12/2008 0.1464 0.1464 18.3 4.26 7.48

6/13/2008 0.156 0.156 338 320 4 3 19 4.4 7.47

6/14/2008 0.1584 0.1584

6/15/2008 0.168 0.168

6/16/2008 0.168 0.168 20.1 3.16 7.43

6/17/2008 0.1608 0.1608 20.1 4.15 7.47

6/18/2008 0.1392 0.1392 275 202 9 4 19.3 3.72 7.41

6/19/2008 0.1512 0.1512 19.1 4.25 7.38

6/20/2008 0.156 0.156 310 484 8 7 19.5 4.57 7.44

6/21/2008 0.1584 0.1584

6/22/2008 0.1776 0.1776

6/23/2008 0.1728 0.1728 19.9 3.97 7.45

6/24/2008 0.1536 0.1536 19.5 4.2 7.45

6/25/2008 0.1584 0.1584 247 192 7 9 19.7 4.1 7.37

6/26/2008 0.1632 0.1632 20.2 4.08 7.48

6/27/2008 0.1656 0.1656 294 280 8 9 20.2 4.76 7.47

6/28/2008 0.118 0.118

6/29/2008 0.1824 0.1824

6/30/2008 0.1896 0.1896 22.7 3.17 7.51

7/1/2008 0.204 0.204 24.6

7/2/2008 0.18 0.18 274 184 22.6

7/3/2008 0.1944 0.1944

7/4/2008 0.204 0.204

7/5/2008 0.2616 0.2616

7/6/2008 0.2763 0.2763

7/7/2008 0.264 0.264 21.5

7/8/2008 0.216 0.216 22.2

7/9/2008 0.1776 0.1776 237 186 21.8

7/10/2008 0.1872 0.1872 21.9

7/11/2008 0.18 0.18 232 252 21.9

7/12/2008 0.1704 0.1704

7/13/2008 0.1824 0.1824

7/14/2008 0.1776 0.1776 21.6

7/15/2008 0.2016 0.2016 22.4

7/16/2008 0.1992 0.1992 247 186 21.8

7/17/2008 0.1872 0.1872 21.1

7/18/2008 0.1776 0.1776 225 250 20.7

7/19/2008 0.168 0.168

7/20/2008 0.1608 0.1608

7/21/2008 0.1656 0.1656 20.5

7/22/2008 0.1704 0.1704 21.2

7/23/2008 0.1872 0.1872 251 292 20.7

7/24/2008 0.1584 0.1584 20.8

7/25/2008 0.1656 0.1656 308 444 20.9

7/26/2008 0.1971 0.1971

7/27/2008 0.1896 0.1896

7/28/2008 0.1752 0.1752 21.2

7/29/2008 0.156 0.156 20.6

7/30/2008 0.1608 0.1608 296 256 20.5

7/31/2008 0.1536 0.1536 20.9

8/1/2008 0.168 0.168 262 270 4 4 20.3 4.14 7.55

8/2/2008 0.1296 0.1296

8/3/2008 0.1242 0.1242

8/4/2008 0.1656 0.1656 20.8 5 7.35

8/5/2008 0.1632 0.1632 20.7 5.5 7.12

8/6/2008 0.1704 0.1704 270 234 6 5 20.7 4.2 7.38

8/7/2008 0.1704 0.1704 20.8 5.12 7.12

8/8/2008 0.1848 0.1848 218 182 3 0.4 20.9 4.2 7.15

8/9/2008 0.192 0.192

8/10/2008 0.1752 0.1752

8/11/2008 0.1656 0.1656 21.1 4.97 7.38

8/12/2008 0.1752 0.1752 23.1 5.67 7.32

8/13/2008 0.18 0.18 233 172 2 0.2 23 5.98 7.37

8/14/2008 0.1824 0.1824 20.6 4.43 7.14

8/15/2008 0.1872 0.1872 238 214 2 2 21.4 4.3 7.25

8/16/2008 0.204 0.204

8/17/2008 0.2184 0.2184

8/18/2008 0.2232 0.2232 23.1 5.61 7.31

8/19/2008 0.2088 0.2088 22.1 4.2 7.52

8/20/2008 0.192 0.192 217 176 2 2 21.6 4.4 7.17

8/21/2008 0.3408 0.3408 20.1 6.34 7.27

8/22/2008 0.18 0.18 256 238 2 0.4 19.6 4.65 7.03

8/23/2008 0.1728 0.1728

8/24/2008 0.1608 0.1608

8/25/2008 0.1869 0.1869 20.4 6.67 7.33

8/26/2008 0.1536 0.1536 19.6 7 7.29

8/27/2008 0.1704 0.1704 19.5 7.02 7.3

8/28/2008 0.1608 0.1608 266 218 2 1 20.6 5.52 7.35

8/29/2008 0.1392 0.1392 236 332 2 0.8 20.7 4.28 7.09

8/30/2008 0.1707 0.1707

8/31/2008 0.2507 0.2507

9/1/2008 0.1248 0.1248 19 4.00 6.92

9/2/2008 0.1248 0.1248 19.2 4.31 6.96

9/3/2008 0.1032 0.1032 257 144 2 0.2 18.6 6.16 7.19

9/4/2008 0.1032 0.1032 19 5.00 7.18

9/5/2008 0.1152 0.1152 249 314 2 0.4 19.5 4.36 7.1

9/6/2008 0.1344 0.1344

9/7/2008 0.132 0.132

9/8/2008 0.1392 0.1392 19.9 5.16 7.29

9/9/2008 0.108 0.108 17.9 6.74 7.3

9/10/2008 0.144 0.144 343 228 2 0.4 18.9 6.28 7.29

9/11/2008 0.1176 0.1176 20.4 4.30 6.95

9/12/2008 0.1392 0.1392 447 749 2 5 19.7 4.32 6.92

9/13/2008 0.1656 0.1656

9/14/2008 0.1536 0.1536

9/15/2008 0.1752 0.1752 19.9 3.84 6.89

9/16/2008 0.1536 0.1536 18.4 4.47 6.91

9/17/2008 0.1416 0.1416 331 220 0.4 19 3.70 6.88

9/18/2008 0.1584 0.1584 19.3 4.84 6.94

9/19/2008 0.1656 0.1656 292 254 2 20.2 4.41 6.92

9/20/2008 0.1728 0.1728

9/21/2008 0.1733 0.1733

9/22/2008 0.1608 0.1608 18.9 3.64 6.92

9/23/2008 0.175 0.175 17.6 4.13 6.92

9/24/2008 0.1125 0.1125

9/25/2008 0.144 0.144 18.6 5.45 6.97

9/26/2008 0.2832 0.2832 311 274 3 3 18.2 5.50 7.06

9/27/2008 0.144 0.144

9/28/2008 0.1608 0.1608

9/29/2008 0.1728 0.1728 18.4 4.27 6.88

9/30/2008 0.168 0.168 19 5.69 6.97

10/1/2008 0.1464 0.1464 18.2 3.55 6.85

10/2/2008 0.1632 0.1632 18.6 4.52 6.94

10/3/2008 0.168 0.168 290 346 3 0.8 19.1 4.2 6.94

10/4/2008 0.12 0.12

10/5/2008 0.204 0.204

10/6/2008 0.1944 0.1944 18.3 4.33 7.09

10/7/2008 0.1632 0.1632 18.2 4 7.08

10/8/2008 0.168 0.168 285 182 2 0.8 17.5 4.92 7.11

10/9/2008 0.192 0.192 16.9 4.31 7.02

10/10/2008 0.1572 0.1572 239 164 2 1 16.2 7.01 7.22

10/11/2008 0.1707 0.1707

10/12/2008 0.1979 0.1979

10/13/2008 0.1944 0.1944 16.2 3.8 6.99

10/14/2008 0.18 0.18 17.5 3.98 7.04

10/15/2008 0.1512 0.1512 15.9 5.79 7.09

10/16/2008 0.168 0.168 308 232 5 1 17.3 3.86 7.11

10/17/2008 0.1464 0.1464 290 160 7 2 17.3 3.43 7.09

10/18/2008 0.1656 0.1656

10/19/2008 0.1584 0.1584

10/20/2008 0.168 0.168 16.7 5.09 7.23

10/21/2008 0.1368 0.1368 15.3 3.12 6.9

10/22/2008 0.1584 0.1584 285 164 7 0.8 13.8 3.19 7.12

10/23/2008 0.1656 0.1656 15.7 3.26 7.09

10/24/2008 0.1584 0.1584 350 266 6 1 14.9 3.1 7.11

10/25/2008 0.1464 0.1464

10/26/2008 0.1848 0.1848

10/27/2008 0.2474 0.2474 14.9 5.16 7.16

10/28/2008 0.2352 0.2352 15 3.62 7.02

10/29/2008 0.1944 0.1944 279 224 11 6 16.5 3 7.08

10/30/2008 0.1584 0.1584 16.4 2.4 7.08

10/31/2008 0.132 0.132 315 158 8 3 16.8 4.28 7.15

11/1/2008 0.1034 0.1034

11/2/2008 0.1032 0.1032

11/3/2008 0.1464 0.1464 17.2

11/4/2008 0.1248 0.1248 16.3

11/5/2008 0.1272 0.1272 268 160 16.2

11/6/2008 0.1344 0.1344 16

11/7/2008 0.1056 0.1056 261 142 16.4

11/8/2008 0.1536 0.1536

11/9/2008 0.2064 0.2064

11/10/2008 0.1944 0.1944 16

11/11/2008 0.132 0.132

11/12/2008 0.1416 0.1416 344 204 17.7

11/13/2008 0.2088 0.2088 17

11/14/2008 0.1608 0.1608 243 144 14.4

11/15/2008 0.1704 0.1704

11/16/2008 0.1656 0.1656

11/17/2008 0.1584 0.1584 13.5

11/18/2008 0.1272 0.1272 14

11/19/2008 0.1224 0.1224 335 200 13

11/20/2008 0.1368 0.1368 14.7

11/21/2008 0.1344 0.1344 300 192 15

11/22/2008 0.1397 0.1397

11/23/2008 0.1608 0.1608

11/24/2008 0.1848 0.1848 12.4

11/25/2008 0.168 0.168 14.4

11/26/2008 0.108 0.108 391 332 14.3

11/27/2008 0.1056 0.1056

11/28/2008 0.1488 0.1488

11/29/2008 0.1416 0.1416

11/30/2008 0.1512 0.1512

12/1/2008 0.1368 0.1368 14.9 4.1 7.18

12/2/2008 0.1907 0.1907 14.4 3.59 7.18

12/3/2008 0.108 0.108 307 174 6 8 14.1 4.38 7.22

12/4/2008 0.14 0.14 13.8 5.3 7.28

12/5/2008 0.1896 0.1896 248 222 6 8 13.3 4.4 7.24

12/6/2008 0.1728 0.1728

12/7/2008 0.1728 0.1728

12/8/2008 0.1572 0.1572 12.8 4.35 7.19

12/9/2008 0.1848 0.1848 12.7 5.48 7.2

12/10/2008 0.1728 0.1728 375 170 6 2 13.3 5.33 7.26

12/11/2008 0.1728 0.1728 12.6 4.88 7.21

12/12/2008 0.178 0.178 280 266 6 5 13.4 4.2 7.24

12/13/2008 0.1056 0.1056

12/14/2008 0.1446 0.1446

12/15/2008 0.228 0.228 8.8 4.48 7.25

12/16/2008 0.1776 0.1776 7.1 6.86 7.18

12/17/2008 0.1512 0.1512 328 240 6 5 8.5 5.9 7.25

12/18/2008 0.1152 0.1152 10.1 5.96 7.23

12/19/2008 0.1296 0.1296 192 162 7 6 11.3 4.68 7.26

12/20/2008 0.1584 0.1584

12/21/2008 0.1158 0.1158

12/22/2008 0.1296 0.1296 10 4.6 7.18

12/23/2008 0.1248 0.1248 9.8 4.88 7.2

12/24/2008 0.128 0.128 165 192 4 7 10.3 4.36 7.2

12/25/2008 0.18 0.18

12/26/2008 0.1704 0.1704

12/27/2008 0.108 0.108

12/28/2008 0.1296 0.1296

12/29/2008 0.1344 0.1344 11.7 4.53 7.2

12/30/2008 0.1608 0.1608 12.6 6.57 7.17

12/31/2008 0.1632 0.1632 331 250 10 11 12.7 4.9 7.22

1/1/2009 0.1248 0.1248

1/2/2009 0.1392 0.1392

1/3/2009 0.144 0.144

1/4/2009 0.1464 0.1464

1/5/2009 0.2376 0.2376 11.5

1/6/2009 0.1056 0.1056 11.4

1/7/2009 0.1008 0.1008 313 184 13.6

1/8/2009 0.1752 0.1752 13

1/9/2009 0.1104 0.1104 274 352 11.5

1/10/2009 0.1392 0.1392

1/11/2009 0.1104 0.1104

1/12/2009 0.1056 0.1056 12.6

1/13/2009 0.1032 0.1032 10.6

1/14/2009 0.1056 0.1056 277 160 12.1

1/15/2009 0.108 0.108 11.5

1/16/2009 0.1608 0.1608 289 368 12.4

1/17/2009 0.1656 0.1656

1/18/2009 0.168 0.168

1/19/2009 0.1608 0.1608

1/20/2009 0.1632 0.1632 11.1

1/21/2009 0.1632 0.1632 365 240 12.4

1/22/2009 0.1728 0.1728 10.9

1/23/2009 0.1608 0.1608 262 246 11.2

1/24/2009 0.1704 0.1704

1/25/2009 0.1776 0.1776

1/26/2009 0.1896 0.1896 9.3

1/27/2009 0.1824 0.1824 9.5

1/28/2009 0.1704 0.1704 308 150 9.5

1/29/2009 0.1488 0.1488 10.5

1/30/2009 0.1512 0.1512 290 232 10.4

1/31/2009 0.1296 0.1296

2/1/2009 0.1608 0.1608

2/2/2009 0.1560 0.1560 11.3 4.5 7.24

2/3/2009 0.1536 0.1536 9.3 4.11 7.13

2/4/2009 0.1632 0.1632 300 150 8 5 11 4.99 7.26

2/5/2009 0.1680 0.1680 10.4 4.9 7.27

2/6/2009 0.1152 0.1152 311 338 6 5 10.2 4.5 7.29

2/7/2009 0.1909 0.1909

2/8/2009 0.1506 0.1506

2/9/2009 0.1944 0.1944 11.5 4.18 7.25

2/10/2009 0.1488 0.1488 9.9 4.16 7.24

2/11/2009 0.1728 0.1728 11.7 4.41 7.23

2/12/2009 0.1296 0.1296 476 332 7 4 11.3 4.77 7.29

2/13/2009 0.1512 0.1512 320 286 7 7 11.8 4.28 7.26

2/14/2009 0.1608 0.1608

2/15/2009 0.1368 0.1368

2/16/2009 0.1008 0.1008

2/17/2009 0.1224 0.1224 11.9 3.94 7.27

2/18/2009 0.1296 0.1296 325 174 7 4 11.9 4.12 7.24

2/19/2009 0.1488 0.1488 12.5 6.41 7.38

2/20/2009 0.1080 0.1080 289 282 7 5 12 4.5 7.23

2/21/2009 0.1416 0.1416

2/22/2009 0.1344 0.1344

2/23/2009 0.1656 0.1656 12.5 4.47 7.15

2/24/2009 0.1440 0.1440 11.8 4.63 7.23

2/25/2009 0.1464 0.1464 287 148 4 2 11.7 4.93 7.26

2/26/2009 0.1656 0.1656 10.7 5.05 7.31

2/27/2009 0.1632 0.1632 227 202 6 2 10.5 4.55 7.3

2/28/2009 0.1944 0.1944

3/1/2009

3/2/2009 0.132 0.132 12.3

3/3/2009 0.1272 0.1272 11.9

3/4/2009 0.096 0.096 260 230 12

3/5/2009 0.12 0.12 12.1

3/6/2009 0.1344 0.1344 285 196 12.2

3/7/2009

3/8/2009

3/9/2009 0.1368 0.1368 10.3

3/10/2009 0.1512 0.1512 10.5

3/11/2009 0.1632 0.1632 317 224 11.2

3/12/2009 0.1608 0.1608 9.9

3/13/2009 0.1368 0.1368 296 312 11.4

3/14/2009

3/15/2009

3/16/2009 0.1728 0.1728 12.8

3/17/2009 0.1152 0.1152 11.9

3/18/2009 0.108 0.108 355 176 13.2

3/19/2009 0.1344 0.1344 12.1

3/20/2009 0.144 0.144 288 246 13.4

3/21/2009

3/22/2009

3/23/2009 0.1416 0.1416 11.7

3/24/2009 0.1392 0.1392 13.3

3/25/2009 0.1416 0.1416 266 204 13.5

3/26/2009 0.108 0.108 11.9

3/27/2009 0.1344 0.1344 250 184 13.5

3/28/2009

3/29/2009

3/30/2009 0.132 0.132 12.5

3/31/2009 0.108 0.108 14.1

4/1/2009 0.1104 0.1104 180 204 7 8 12.2 4.25 7.29

4/2/2009 0.1008 0.1008 13.3 4.52 7.22

4/3/2009 0.1368 0.1368 348 346 10 2 13.2 4.12 7.31

4/4/2009

4/5/2009

4/6/2009 0.1632 0.1632 13.8 4.01 7.25

4/7/2009 0.1512 0.1512 14.3 4.18 7.27

4/8/2009 0.1488 0.1488 332 264 9 5 15.6 4.42 7.30

4/9/2009 0.1392 0.1392 14.7 4.1 7.31

4/10/2009 0.1152 0.1152 306 312 7 7 15 4.49 7.32

4/11/2009

4/12/2009

4/13/2009 0.1512 0.1512 15.9 4.87 7.25

4/14/2009 0.1224 0.1224 13.6 4.01 7.34

4/15/2009 0.1272 0.1272 375 180 6 4 13.2 4.16 7.29

4/16/2009 0.1440 0.1440 15.4 5.02 7.17

4/17/2009 0.1488 0.1488 310 282 12 9 15.6 4.77 7.2

4/18/2009

4/19/2009

4/20/2009 0.1776 0.1776 16.3 3.96 7.22

4/21/2009 0.1584 0.1584 17.5 4.07 7.22

4/22/2009 0.1632 0.1632 17.1 4.12 7.2

4/23/2009 0.1296 0.1296 15 4.18 7.21

4/24/2009 0.1104 0.1104 387 522 9 25 15.1 4.23 7.31

4/25/2009

4/26/2009

4/27/2009 0.1368 0.1368 15.7 3.67 7.27

4/28/2009 0.1320 0.1320 15.3 3.85 7.29

4/29/2009 0.1056 0.1056 489 266 9 35 15.2 3.98 7.3

4/30/2009 0.1104 0.1104 15.1 3.96 7.31

5/1/2009 0.1344 0.1344 503 1336 6 39 15 4.02 7.32

5/2/2009

5/3/2009

5/4/2009 0.144 0.144 15.2 3.96 7.35

5/5/2009 0.1296 0.1296 16.5 4.2 7.31

5/6/2009 0.1608 0.1608 356 270 9 24 15.5 3.99 7.28

5/7/2009 0.1416 0.1416 16.3 4.59 7.25

5/8/2009 0.144 0.144 299 280 9 49 15.5 5.5 7.29

5/9/2009

5/10/2009

5/11/2009 0.0178 0.0178 15.1 3.99 7.32

5/12/2009 0.1728 0.1728 16.1 4.1 7.26

5/13/2009 0.1248 0.1248 334 206 9 48 15.6 4.16 7.37

5/14/2009 0.1176 0.1176 17.2 4 7.31

5/15/2009 0.1536 0.1536 319 372 6 44 16.5 4.05 7.31

5/16/2009

5/17/2009

5/18/2009 0.1872 0.1872 18.9 4.2 7.3

5/19/2009 0.1776 0.1776 18.9 4.5 7.28

5/20/2009 0.1461 0.1461 377 400 6 30 18.6 4.9 7.32

5/21/2009 0.1416 0.1416 16.4 3.99 7.3

5/22/2009 0.1416 0.1416 233 204 5 26 18 4.05 7.32

5/23/2009

5/24/2009

5/25/2009

5/26/2009 0.2112 0.2112 20 4 7.29

5/27/2009 0.1896 0.1896 278 286 6 35 19.9 4.1 7.31

5/28/2009 0.1872 0.1872 20 450 7.28

5/29/2009 0.1992 0.1992 298 286 5 32 19.7 420 7.28

5/30/2009

5/31/2009

6/1/2009 0.216 0.216 4.15 7.33

6/2/2009 0.2136 0.2136 5.75 7.34

6/3/2009 0.2112 0.2112 298 302 6 36 4.25 7.37

6/4/2009 0.204 0.204 5 7.36

6/5/2009 0.1656 0.1656 284 268 7 34 4.37 7.41

6/6/2009

6/7/2009

6/8/2009 0.1992 0.1992 4.15 7.42

6/9/2009 0.192 0.192 4.25 7.40

6/10/2009 0.1704 0.1704 273 322 5 37 3.99 7.34

6/11/2009 0.192 0.192 5 7.35

6/12/2009 0.1776 0.1776 301 220 7 47 4 7.32

6/13/2009

6/14/2009

6/15/2009 0.1542 0.1542 4.15 7.29

6/16/2009 0.2328 0.2328 4.45 7.28

6/17/2009 0.1344 0.1344 256 338 7 39 3.95 7.27

6/18/2009 0.1287 0.1287 4.02 7.25

6/19/2009 0.192 0.192 282 208 7 32 4.31 7.25

6/20/2009

6/21/2009

6/22/2009 0.1752 0.1752 4 7.28

6/23/2009 0.18 0.18 4.2 7.31

6/24/2009 0.1944 0.1944 259 252 8 38 4.04 7.31

6/25/2009 0.2016 0.2016 4.16 7.29

6/26/2009 0.1848 0.1848 308 282 7 36 4.02 7.26

6/27/2009

6/28/2009

6/29/2009 0.2064 0.2064 4.05 7.26

6/30/2009 0.18 0.18 4 7.28

7/1/2009 0.1848 0.1848 264 264 8 39 4.15 7.26

7/2/2009 0.18 0.18 4.02 7.25

7/3/2009

7/4/2009

7/5/2009

7/6/2009 0.2064 0.2064 4.3 7.27

7/7/2009 0.1728 0.1728 4.35 7.27

7/8/2009 0.1608 0.1608 316 288 7 40 4.5 7.28

7/9/2009 0.1608 0.1608 4.32 7.26

7/10/2009 0.1656 0.1656 323 340 7 44 4 7.26

7/11/2009

7/12/2009

7/13/2009 0.2136 0.2136 4.1 7.23

7/14/2009 0.1896 0.1896 4 7.23

7/15/2009 0.1752 0.1752 310 394 7 52 4.6 7.2

7/16/2009 0.1782 0.1782 4.62 7.22

7/17/2009 0.2016 0.2016 281 248 8 49 4.2 7.19

7/18/2009

7/19/2009

7/20/2009 0.2064 0.2064 4 7.26

7/21/2009 0.1944 0.1944 4.6 7.24

7/22/2009 0.2136 0.2136 265 270 8 47 4.15 7.21

7/23/2009 0.2064 0.2064 4.04 7.21

7/24/2009 0.1776 0.1776 315 276 7 45 4.34 7.22

7/25/2009

7/26/2009

7/27/2009 0.2064 0.2064 4.21 7.27

7/28/2009 0.2064 0.2064 4.4 7.26

7/29/2009 0.2088 0.2088 331 320 7 39 4.04 7.3

7/30/2009 0.2112 0.2112 4.5 7.27

7/31/2009 0.2016 0.2016 317 222 6 49 3.98 7

8/1/2009

8/2/2009

8/3/2009 0.2016 0.2016 23.00 4.1 7.28

8/4/2009 0.1752 0.1752 24.20 4.2 7.28

8/5/2009 0.216 0.216 230 224 8 36 23.30 4 7.3

8/6/2009 0.1992 0.1992 22.60 4.06 7.3

8/7/2009 0.1968 0.1968 307 230 8 27 21.30 4.38 7.29

8/8/2009

8/9/2009

8/10/2009 0.204 0.204 21.90 4.55 7.29

8/11/2009 0.1992 0.1992 22.20 4.12 7.33

8/12/2009 0.216 0.216 232 208 9 39 22.20 4.3 7.34

8/13/2009 0.216 0.216 22.10 4.44 7.35

8/14/2009 0.1992 0.1992 301 260 9 26 20.90 4.09 7.32

8/15/2009

8/16/2009

8/17/2009 0.1872 0.1872 21.40 4.08 7.27

8/18/2009 0.1896 0.1896 21.80 4.36 7.29

8/19/2009 0.2112 0.2112 235 232 9 28 21.60 4.5 7.27

8/20/2009 0.216 0.216 22.20 4.04 7.28

8/21/2009 0.2304 0.2304 277 180 8 21 23.10 4.15 7.24

8/22/2009

8/23/2009

8/24/2009 0.204 0.204 20.90 4.04 7.29

8/25/2009 0.1752 0.1752 21.90 4.27 7.31

8/26/2009 0.1776 0.1776 381 256 9 13 21.20 4.06 7.33

8/27/2009 0.18 0.18

8/28/2009 0.1848 0.1848 300 286 8 23 21.30 4.25 7.28

8/29/2009

8/30/2009

8/31/2009 0.2328 0.2328 22.20 4.05 7.23

9/1/2009 0.1339 0.1339

9/2/2009 0.2184 0.2184 22.50 4.02 7.31

9/3/2009 0.2136 0.2136 21.90 4.33 7.32

9/4/2009 0.1920 0.1920 307 336 9 8 20.60 4.05 7.33

9/5/2009

9/6/2009

9/7/2009

9/8/2009 0.1800 0.1800 19.50 4.10 7.34

9/9/2009 0.1656 0.1656 279 262 9 6 20.10 4.61 7.35

9/10/2009 0.1776 0.1776 19.90 4.33 7.34

9/11/2009 0.1728 0.1728 384 288 8 8 20.10 4.22 7.32

9/12/2009

9/13/2009

9/14/2009 0.2304 0.2304 21.10 4.00 7.29

9/15/2009 0.2160 0.2160 21.40 4.40 7.33

9/16/2009 0.1896 0.1896 272 324 9 12 20.20 4.30 7.35

9/17/2009 0.2064 0.2064 20.80 4.54 7.34

9/18/2009 0.2016 0.2016 347 344 9 8 19.70 4.22 7.32

9/19/2009

9/20/2009

9/21/2009 0.1704 0.1704 20.10 4.10 7.36

9/22/2009 0.1560 0.1560 18.90 4.40 7.33

9/23/2009 0.1728 0.1728 277 250 6 4 19.40 4.10 7.33

9/24/2009 0.1920 0.1920 19.70 4.42 7.32

9/25/2009 0.1824 0.1824 302 278 7 3 19.60 4.62 7.32

9/26/2009

9/27/2009

9/28/2009 0.1920 0.1920 18.60 4.15 7.32

9/29/2009 0.1776 0.1776 18.60 4.10 7.35

9/30/2009 0.1608 0.1608 203 190 8 8 18.50 4.04 7.20

10/1/2009 0.1896 0.1896 18.40

10/2/2009 0.1920 0.1920 263 226 18.50

10/3/2009

10/4/2009

10/5/2009 0.1776 0.1776 17.00

10/6/2009 0.1272 0.1272 17.10

10/7/2009 0.1680 0.1680 284 300 17.60

10/8/2009 0.1440 0.1440 18.20

10/9/2009 0.1128 0.1128 17.40

10/10/2009

10/11/2009

10/12/2009 0.1704 0.1704 15.70

10/13/2009 0.1536 0.1536 17.20

10/14/2009 0.1800 0.1800 310 380 17.60

10/15/2009 0.1080 0.1080 18.40

10/16/2009 0.1152 0.1152 247 236 17.60

10/17/2009

10/18/2009

10/19/2009 0.1632 0.1632 19.30

10/20/2009 0.1080 0.1080 17.60

10/21/2009 0.1056 0.1056 288 342 18.10

10/22/2009 0.1200 0.1200 18.30

10/23/2009 0.1296 0.1296 295 300 18.20

10/24/2009

10/25/2009

10/26/2009 0.1536 0.1536 17.10

10/27/2009 0.1200 0.1200 16.60

10/28/2009 0.1200 0.1200 241 260 16.10

10/29/2009 0.1368 0.1368 16.10

10/30/2009 0.1500 0.1500 348 416 16.00

10/31/2009

11/1/2009

11/2/2009 0.1368 0.1368 15.20 4.50 7.14

11/3/2009 0.1152 0.1152 14.60 4.24 7.20

11/4/2009 0.1080 0.1080 152 112 5 2 16.30 4.14 7.17

11/5/2009 0.1056 0.1056 15.10 4.08 7.15

11/6/2009 0.1000 0.1000 14.60 4.55 7.17

11/7/2009

11/8/2009

11/9/2009 0.1008 0.1008 15.30 4.10 7.11

11/10/2009 0.1200 0.1200 14.90 4.53 7.16

11/11/2009

11/12/2009

11/13/2009 0.1128 0.1128 386 236 4 1 13.00 4.75 7.12

11/14/2009

11/15/2009

11/16/2009 0.1488 0.1488 14.10 4.80 7.08

11/17/2009 0.1632 0.1632 15.00 4.75 7.08

11/18/2009 0.1632 0.1632 284 222 3 0.20 17.00 4.44 7.06

11/19/2009 0.1488 0.1488 15.10 4.46 7.07

11/20/2009 0.1656 0.1656 349 256 4 3 14.70 4.29 7.08

11/21/2009

11/22/2009

11/23/2009 0.1176 0.1176 13.90 4.54 7.08

11/24/2009 0.1536 0.1536 15.00 4.53 7.08

11/25/2009 0.1584 0.1584 307 342 6 3 14.90 4.50 7.08

11/26/2009

11/27/2009

11/28/2009

11/29/2009

11/30/2009 0.1608 0.1608 4.14 7.14

12/1/2009 0.1080 0.1080 12.80 4.42 7.14

12/2/2009 0.1152 0.1152 352 492 2.00 0.60 11.20 4.40 7.18

12/3/2009 0.1800 0.1800 11.40 4.54 7.20

12/4/2009 0.1680 0.1680 296 264 2.00 0.80 11.10 4.39 7.13

12/5/2009

12/6/2009

12/7/2009 0.1800 0.1800 9.40 4.10 7.13

12/8/2009 0.1656 0.1656 8.60 4.60 7.17

12/9/2009 0.1800 0.1800 6.70 4.94 7.16

12/10/2009 0.1680 0.1680 7.60 4.85 7.18

12/11/2009 0.1488 0.1488 502 364 3.00 0.20 7.50 5.05 7.16

12/12/2009

12/13/2009

12/14/2009 0.1080 0.1080 10.10 4.30 7.13

12/15/2009 0.1176 0.1176 11.50 4.34 7.14

12/16/2009 0.1152 0.1152 411 782 5.00 4.00 14.20 4.69 7.13

12/17/2009 0.1130 0.1130 11.90 4.57 7.13

12/18/2009 0.1200 0.1200 259 200 2.00 0.60 13.80 5.25 7.17

12/19/2009

12/20/2009

12/21/2009 0.1160 0.1160 14.80 4.10 7.14

12/22/2009 0.1380 0.1380 13.00 4.31 7.15

12/23/2009 0.1392 0.1392 344 282 3.00 1.60 11.90 4.77 7.12

12/24/2009 0.1272 0.1272 11.60 4.88 7.11

12/25/2009

12/26/2009

12/27/2009

12/28/2009 0.1565 0.1565 9.70 4.70 7.05

12/29/2009 0.1056 0.1056 11.80 5.03 7.04

12/30/2009 0.1128 0.1128 340 294 2.00 2.00 10.80 5.00 7.04

12/31/2009 0.1056 0.1056 12.00 5.50 7.04

1/1/2010

1/2/2010

1/3/2010

1/4/2010 0.17600 0.17600 11.90 4.04 7.00

1/5/2010 0.11600 0.11600 12.80 4.40 7.03

1/6/2010 0.10560 0.10560 243.00 212.00 2.00 0.20 14.30 5.05 7.04

1/7/2010 0.11100 0.11100

1/8/2010 0.15600 0.15600 367.00 360.00 3.00 2.00 12.30 4.45 7.05

1/9/2010

1/10/2010

1/11/2010 0.15840 0.15840 12.10 4.20 6.96

1/12/2010 0.15600 0.15600 13.10 4.10 6.98

1/13/2010 0.14640 0.14640 12.30 4.34 6.99

1/14/2010 0.15600 0.15600 228.00 334.00 8.00 2.00 13.50 4.60 6.99

1/15/2010 0.19920 0.19920 346.00 320.00 8.00 7.00 13.30 4.30 6.98

1/16/2010

1/17/2010

1/18/2010

1/19/2010 0.11280 0.11280 13.70 4.20 7.01

1/20/2010 0.11040 0.11040 313.00 288.00 6.00 4.00 13.20 4.50 6.98

1/21/2010 0.12720 0.12720 13.70 4.20 7.00

1/22/2010 0.12960 0.12960 353.00 206.00 7.00 6.00 12.70 4.30 7.07

1/23/2010

1/24/2010

1/25/2010 0.14400 0.14400 12.80 4.20 7.01

1/26/2010 0.11760 0.11760 14.40 4.37 6.96

1/27/2010 0.13440 0.13440 365.00 442.00 6.00 6.00 19.012.9 4.40 7.02

1/28/2010 0.19440 0.19440 14.50 4.10 7.01

1/29/2010 0.17520 0.17520 339.00 278.00 7.00 6.00 4.15 6.95

1/30/2010

1/31/2010

2/1/2010 0.16800 0.16800 14.60 4.10 6.97

2/2/2010 0.12960 0.12960 14.60 4.20 7.00

2/3/2010 0.17760 0.17760 500.00 422.00 7.00 9.00 16.00 4.15 6.98

2/4/2010 0.20400 0.20400 16.30 4.12 7.00

2/5/2010 0.18960 0.18960 262.00 224.00 8.00 10.00 15.00 4.75 7.01

2/6/2010

2/7/2010

2/8/2010 0.19200 0.19200 15.60 4.08 7.05

2/9/2010 0.16000 0.16000 16.00 4.43 7.06

2/10/2010 0.15840 0.15840 14.60 4.24 7.07

2/11/2010 0.17280 0.17280 316.00 376.00 6.00 7.00 14.90 4.20 7.07

2/12/2010 0.15840 0.15840 372.00 378.00 7.00 6.00 14.20 4.30 7.06

2/13/2010

2/14/2010

2/15/2010

2/16/2010 0.12960 0.12960 14.50 4.17 7.07

2/17/2010 0.12720 0.12720 310.00 264.00 6.00 12.00 15.00 4.32 7.06

2/18/2010 0.12000 0.12000 15.10 4.50 7.10

2/19/2010 0.12960 0.12960 281.00 118.00 2.00 0.20 13.80 4.44 7.12

2/20/2010

2/21/2010

2/22/2010 0.17280 0.17280 13.70 4.50 7.11

2/23/2010 0.15840 0.15840 13.00 4.30 7.10

2/24/2010 0.13920 0.13920 277.00 250.00 5.00 1.00 13.10 4.12 7.09

2/25/2010 0.10560 0.10560 15.00 4.82 7.11

2/26/2010 0.10420 0.10420 334.00 210.00 4.00 0.80 14.30 4.37 7.09

2/27/2010 0.16870 0.16870

2/28/2010 0.16870 0.16870

3/1/2010

3/2/2010

3/3/2010

3/4/2010

3/5/2010

3/6/2010

3/7/2010

3/8/2010

3/9/2010

3/10/2010

3/11/2010

3/12/2010

3/13/2010

3/14/2010

3/15/2010

3/16/2010

3/17/2010

3/18/2010

3/19/2010

3/20/2010

3/21/2010

3/22/2010

3/23/2010

3/24/2010

3/25/2010

3/26/2010

3/27/2010

3/28/2010

3/29/2010

3/30/2010

3/31/2010

4/1/2010 0.15700 0.15700 15.60 6.10 6.80

4/2/2010 0.11500 0.11500 348.00 119.00 8.00 13.00 14.00 5.80 6.70

4/3/2010 0.11500 0.11500

4/4/2010 0.11500 0.11500

4/5/2010 0.14200 0.14200 14.70 6.10 6.40

4/6/2010 0.14700 0.14700 491.00 161.00 8.00 20.00 15.20 5.70 5.90

4/7/2010 0.14900 0.14900 16.00 4.60 5.70

4/8/2010 0.14700 0.14700 371.00 358.00 3.00 48.00 15.80 5.10 6.70

4/9/2010 0.14400 0.14400 16.40 5.10 6.70

4/10/2010 0.14400 0.14400

4/11/2010 0.14400 0.14400

4/12/2010 0.14600 0.14600 16.20 4.92 6.80

4/13/2010 0.14800 0.14800 344.00 308.00 4.00 32.00 15.60 5.20 7.00

4/14/2010 0.15000 0.15000 16.20 4.50 6.90

4/15/2010 0.15100 0.15100 331.00 262.00 4.00 36.00 16.80 4.90 5.60

4/16/2010 0.18300 0.18300 16.50 5.20 6.90

4/17/2010 0.18300 0.18300

4/18/2010 0.18300 0.18300

4/19/2010 0.14900 0.14900 19.60 1.00 7.30

4/20/2010 0.17700 0.17700 340.00 376.00 11.00 11.00 18.30 3.20 7.00

4/21/2010 0.15600 0.15600 18.00 4.90 6.80

4/22/2010 0.17000 0.17000 390.00 324.00 4.00 35.00 17.40 4.70 6.80

4/23/2010 0.16800 0.16800 16.50 6.30 6.10

4/24/2010 0.16800 0.16800

4/25/2010 0.16800 0.16800

4/26/2010 0.16200 0.16200 16.50 6.60 6.80

4/27/2010 0.16100 0.16100 358.00 362.00 2.00 32.00 17.70 3.80 7.20

4/28/2010 0.16200 0.16200 17.90 6.30 5.40

4/29/2010 0.17200 0.17200 526.00 250.00 4.00 25.00 16.60 8.00 7.20

4/30/2010 0.16800 0.16800 17.80 6.90 7.10

5/1/2010 0.16800 0.16800

5/2/2010 0.16800 0.16800

5/3/2010 0.16800 0.16800 18.10 6.90 6.50

5/4/2010 0.13400 0.13400 303.00 210.00 3.00 11.00 15.60 5.30 6.90

5/5/2010 0.11200 0.11200 15.10 6.60 5.60

5/6/2010 0.11600 0.11600 434.00 260.00 3.00 14.00 15.70 6.10 6.10

5/7/2010 0.16200 0.16200 15.20 5.90 6.80

5/8/2010 0.16200 0.16200

5/9/2010 0.16200 0.16200

5/10/2010 0.16900 0.16900 18.50 5.60 7.00

5/11/2010 0.19500 0.19500 371.00 202.00 1.00 7.00 18.20 6.20 6.90

5/12/2010 0.19600 0.19600 19.20 5.00 7.10

5/13/2010 0.18400 0.18400 388.00 286.00 6.00 10.00 18.40 5.70 7.30

5/14/2010 0.15700 0.15700 20.00 4.50 7.30

5/15/2010 0.15700 0.15700

5/16/2010 0.15700 0.15700

5/17/2010 0.15600 0.15600 20.00 4.00 7.10

5/18/2010 0.16200 0.16200 379.00 297.00 5.00 26.00 21.00 4.80 7.20

5/19/2010 0.15600 0.15600 19.00 4.90 6.90

5/20/2010 0.14200 0.14200 391.00 348.00 9.00 24.00 18.30 4.50 7.30

5/21/2010 0.16300 0.16300 18.10 4.30 7.20

5/22/2010 0.16300 0.16300

5/23/2010 0.16300 0.16300

5/24/2010 0.17200 0.17200 18.10 4.20 7.00

5/25/2010 0.16900 0.16900 388.00 238.00 6.00 15.00 17.90 4.70 7.10

5/26/2010 0.17500 0.17500 18.90 4.60 6.70

5/27/2010 0.21300 0.21300 302.00 290.00 5.00 34.00 18.20 4.40 6.20

5/28/2010 0.18800 0.18800 18.00 4.60 7.00

5/29/2010 0.18800 0.18800

5/30/2010 0.18800 0.18800

5/31/2010 0.18800 0.18800

6/1/2010 0.19000 0.19000 405.00 210.00

6/2/2010 0.18600 0.18600

6/3/2010 0.17600 0.17600 203.00 178.00

6/4/2010 0.17600 0.17600

6/5/2010 0.17600 0.17600

6/6/2010 0.17600 0.17600

6/7/2010 0.19000 0.19000

6/8/2010 0.19900 0.19900 138.00 192.00

6/9/2010 0.17500 0.17500

6/10/2010 0.17300 0.17300 410.00 252.00

6/11/2010 0.19800 0.19800

6/12/2010 0.19800 0.19800

6/13/2010 0.19800 0.19800

6/14/2010 0.17400 0.17400

6/15/2010 0.18800 0.18800 451.00 186.00

6/16/2010 0.17500 0.17500

6/17/2010 0.17600 0.17600 595.00 222.00

6/18/2010 0.15300 0.15300

6/19/2010 0.15300 0.15300

6/20/2010 0.15300 0.15300

6/21/2010 0.19000 0.19000

6/22/2010 0.19500 0.19500 75.00 232.00

6/23/2010 0.20100 0.20100

6/24/2010 0.21100 0.21100 462.00 424.00

6/25/2010 0.19900 0.19900

6/26/2010 0.19900 0.19900

6/27/2010 0.19900 0.19900

6/28/2010 0.19900 0.19900

6/29/2010 0.17500 0.17500 799.00 264.00

6/30/2010 0.17200 0.17200

7/1/2010 0.18200 0.18200 755 232 11 2 18.1 4.56 6.77

7/2/2010 0.19700 0.19700 19.1 5.77 7.22

7/3/2010 0.19700 0.19700 18.6

7/4/2010 0.19700 0.19700

7/5/2010 0.19700 0.19700

7/6/2010 0.20500 0.20500 515 244 7 12 4.57 6.71

7/7/2010 0.19900 0.19900 19.1 4.51 7.22

7/8/2010 0.20200 0.20200 752 292 8 13 18.1 4.13 7.00

7/9/2010 19.1 4.03 7.23

7/10/2010 18.4

7/11/2010 18.6

7/12/2010 0.17600 0.17600 4.96 7.42

7/13/2010 0.17600 0.17600 348 282 8 12 3.62 7.21

7/14/2010 0.18100 0.18100 18.4 4.97 7.41

7/15/2010 0.13400 0.13400 575 218 5 28 18.9 4.34 7.10

7/16/2010 0.14000 0.14000 19.2 4.29 6.98

7/17/2010 0.14000 0.14000 21.2

7/18/2010 0.14000 0.14000 20.6

7/19/2010 0.15600 0.15600 4.65 6.74

7/20/2010 0.15200 0.15200 302 208 4 29 6.47 6.56

7/21/2010 0.15100 0.15100 21.2 6.04 6.61

7/22/2010 0.13900 0.13900 601 166 5 24 21.0 4.93 7.04

7/23/2010 0.10200 0.10200 22.3 4.40 7.26

7/24/2010 0.10200 0.10200 22.9

7/25/2010 0.10200 0.10200 21.7

7/26/2010 0.11300 0.11300 4.41 7.02

7/27/2010 0.11500 0.11500 415 205 7 19 4.92 7.33

7/28/2010 0.10700 0.10700 22.3 4.67 7.14

7/29/2010 0.11500 0.11500 451 238 8 11 22.8 5.18 7.27

7/30/2010 0.11300 0.11300 21.1 5.12 7.39

7/31/2010 0.11300 0.11300

8/1/2010 0.11300 0.11300

8/2/2010 0.11400 0.11400 5.21 7.31

8/3/2010 0.11300 0.11300 497 235 2 23 5.17 7.37

8/4/2010 0.11200 0.11200 5.08 7.38

8/5/2010 0.10800 0.10800 468 344 2 35 5.76 6.95

8/6/2010 0.11000 0.11000 5.71 7.55

8/7/2010 0.11000 0.11000

8/8/2010 0.11000 0.11000

8/9/2010 0.10500 0.10500 5.62 7.24

8/10/2010 0.09100 0.09100 388 206 4 36 5.44 7.14

8/11/2010 0.12200 0.12200 4.46 7.22

8/12/2010 0.11500 0.11500 418 162 3 31 4.58 7.22

8/13/2010 0.10400 0.10400 4.62 7.39

8/14/2010 0.10400 0.10400

8/15/2010 0.10400 0.10400

8/16/2010 0.11200 0.11200 5.53 7.15

8/17/2010 0.11200 0.11200 366 386 3 75 5.45 7.16

8/18/2010 0.09800 0.09800 5.49 7.28

8/19/2010 0.09700 0.09700 587 254 6 37 5.31 7.11

8/20/2010 0.09300 0.09300 4.88 7.13

8/21/2010 0.09300 0.09300

8/22/2010 0.09300 0.09300

8/23/2010 0.09700 0.09700 3.60 7.09

8/24/2010 0.10600 0.10600 412 394 6 73 5.46 7.64

8/25/2010 0.10700 0.10700 5.45 7.46

8/26/2010 0.09600 0.09600 343 266 5 45 5.63 7.22

8/27/2010 0.09100 0.09100 4.18 7.25

8/28/2010 0.09100 0.09100

8/29/2010 0.09100 0.09100

8/30/2010 0.09300 0.09300 5.74 7.20

8/31/2010 0.09200 0.09200 369 296 5 32 5.93 7.24

9/1/2010 0.11400 0.11400 21.34 5.85 7.21

9/2/2010 0.11000 0.11000 305 216 3 38 21.70 6.26 7.46

9/3/2010 0.11000 0.11000 21.70 5.69 7.39

9/4/2010 0.11000 0.11000

9/5/2010 0.11000 0.11000

9/6/2010 0.11000 0.11000 holiday

9/7/2010 0.12800 0.12800 267 346 5 34 20.90 5.44 7.35

9/8/2010 0.12000 0.12000 20.60 4.88 7.37

9/9/2010 0.10100 0.10100 222 239 1 33 21.50 5.67 7.42

9/10/2010 0.15200 0.15200 21.10 5.11 7.32

9/11/2010 0.15200 0.15200

9/12/2010 0.15200 0.15200

9/13/2010 0.10000 0.10000 21.50 6.26 7.43

9/14/2010 0.10200 0.10200 357 352 6 38 21.60 5.40 7.44

9/15/2010 0.10600 0.10600 21.60 5.70 7.28

9/16/2010 0.10200 0.10200 395 163 4 30 21.50 5.61 7.31

9/17/2010 0.10200 0.10200 21.60 5.44 7.27

9/18/2010 0.10200 0.10200

9/19/2010 0.10200 0.10200

9/20/2010 0.09200 0.09200 21.80 5.80 7.36

9/21/2010 0.10700 0.10700 355 170 4 20 20.10 7.79 7.95

9/22/2010 0.07800 0.07800 19.80 6.57 7.54

9/23/2010 0.08200 0.08200 421 153 3 37 19.50 5.73 7.53

9/24/2010 0.11700 0.11700 19.40 6.55 7.52

9/25/2010 0.11700 0.11700

9/26/2010 0.11700 0.11700

9/27/2010 0.12000 0.12000 21.90 5.43 7.08

9/28/2010 0.11300 0.11300 382 171 5 42 21.80 4.65 7.43

9/29/2010 0.11200 0.11200 21.40 4.90 7.22

9/30/2010 0.11800 0.11800 462 212 2 22 21.60 5.09 7.44

10/1/2010 0.12000 0.12000 20.5 4.92 7.24

10/2/2010 0.12000 0.12000

10/3/2010 0.12000 0.12000

10/4/2010 0.09200 0.09200 20.3 4.68 7.31

10/5/2010 0.09100 0.09100 362 485 4 4 19.1 5.05 7.29

10/6/2010 0.07800 0.07800 19.3 5.31 7.08

10/7/2010 0.09200 0.09200 386 257 2 18 19.2 5.24 7.23

10/8/2010 0.12800 0.12800 19.2 4.36 7.14

10/9/2010 0.12800 0.12800

10/10/2010 0.12800 0.12800

10/11/2010 0.08600 0.08600 18.9 4.12 7.43

10/12/2010 0.10400 0.10400 338 366 2 22 18.3 4.42 7.39

10/13/2010 0.10200 0.10200 18.5 5.01 6.93

10/14/2010 0.08700 0.08700 535 341 5 26 18.5 7.07

10/15/2010 0.09000 0.09000 18.4 7.21

10/16/2010 0.09000 0.09000

10/17/2010 0.09000 0.09000

10/18/2010 0.08100 0.08100 19.1 7.25

10/19/2010 0.08800 0.08800 465 180 3 21 17.8 7.35

10/20/2010 0.08000 0.08000 17.5

10/21/2010 0.07100 0.07100 517 632 4 29 17.8

10/22/2010 0.07000 0.07000 17.1

10/23/2010 0.07000 0.07000

10/24/2010 0.07000 0.07000

10/25/2010 0.08100 0.08100 15.9

10/26/2010 0.07100 0.07100 534 590 3 70 16.1

10/27/2010 0.06900 0.06900 15.7

10/28/2010 0.07100 0.07100 345 200 5 29 15.3

10/29/2010 0.11500 0.11500 16.2

10/30/2010 0.11500 0.11500

10/31/2010 0.11500

APPENDIX C

WATER QUALITY EVALUATION

City of Mabton C-1 Wastewater Facility Plan May 2011

APPENDIX C

WATER QUALITY EVALUATION CITY OF MABTON WWTF

INTRODUCTION For a surface water discharge to be permitted, it must be demonstrated that the discharge will not harm beneficial use of the receiving water. The objective of this study is to evaluate the City of Mabton Wastewater Treatment Facility (WWTF) effluent discharge to determine the adequacy of the treatment process and outfall to meet water quality standards and effluent limits that may be required in the future. The wastewater collection and treatment facilities are owned and operated by the City of Mabton. The WWTF receives domestic sewage from the residents, businesses, commercial and public facilities within the City limits. Treatment consists of a rock trap, screening, biological treatment utilizing an oxidation ditch, secondary clarification, UV disinfection, and effluent pumping. This report establishes acute and chronic dilution factors for future effluent flows using both federal and state guidelines. A mixing zone study was performed, and copies of spreadsheets used in this analysis are provided at the end of this section. OUTFALL DESCRIPTION The City has an existing outfall and diffuser buried in the Yakima River. For purposes of this report, the receiving water will be referred to as the Yakima River. Effluent from the secondary treatment facility is discharged via a 10-inch diameter outfall pipe through a single port diffuser. A pump station allows the facility to discharge during high flow conditions in the river. At low river flow conditions, the outfall pipe invert is located approximately one foot from shore, at a depth of 1.5 feet (Esvelt Engineering 2001). The invert is approximately 6 feet above the river bottom elevation (1998 survey), for a total low flow depth of 7.5 feet. As designated in WAC 173-201A-602, the outfall is located in a reach of the Yakima River designated as having an aquatic life use (Salmonoid spawning/rearing). The water quality standards for this section of the River are summarized in Table C-1.


C-2 City of Mabton May 2011 Wastewater Facility Plan

TABLE C-1

Lower Yakima River Water Quality Standards

Characteristic Uses

Salmonoid spawning/rearing Recreational Primary Contact Domestic, Industrial, Agricultural, and Stock Water Wildlife Habitat, Harvesting, Commerce/Navigation, Boating, Aesthetic

Dissolved Oxygen > 8.0 mg/L

Temperature 21oC maximum (1) No increase greater than t=34/(T+9) or (2) If natural temperature is greater than 21oC, no increase >0.3oC

pH Not outside the range of 6.5 to 8.5 standard units Turbidity <5 NTU

Toxics No toxics in toxic amounts EFFLUENT DISCHARGE EVALUATION An outfall evaluation was performed to establish effluent limits for toxic substances based on (1) background water quality and (2) the degree of dilution available in the receiving water with the existing outfall configuration. Future Effluent Flow Characterization The outfall study used dilution calculations based on the projected flows and loadings for the maximum monthly average and maximum daily flows at the WWTF. The maximum monthly flow is used to establish the chronic dilution zone and the maximum daily flow is used to establish the acute dilution zone. Typically, the projected effluent flows in the critical period (dry season) are used for mixing zone analysis. For the City of Mabton the annual maximum month and maximum day flows for the entire year were used, which is a more conservative approach, since it will decrease the dilution factors. The modeling described in this section was conducted in a manner as consistent as possible with previous modeling efforts. The flows used to determine the projected effluent permit limits are 0.29 MGD and 0.69 MGD, respectively, for maximum monthly and maximum daily flow, based on the analysis performed in Chapter 4 of this Wastewater Facility Plan. Receiving Water Characterization River velocity and ambient water quality parameters for the Yakima River used for calculating permit limits in the future permit were taken from the current NPDES permit and fact sheet. (The current NPDES permit was issued on March 19, 2007, and expires on April 30, 2012.) River data is presented in Table C-2.



TABLE C-2 Parameters Used in Current and Future NPDES Permit Limit Calculations

Based on Critical Conditions

PARAMETER VALUE USED IN CURRENT PERMIT

VALUE PROJECTED FOR FUTURE

PERMIT

SOURCE OF PROJECTION FOR FUTURE PERMIT

Receiving Water Temp. 22.78 oC 22.78 oC Current Permit Effluent Temperature 23.83 oC 29 oC DMRs Receiving Water Alkalinity 90 mg/L (as CaCO3) 90 (as CaCO3) Current Permit Effluent Alkalinity 240 (as CaCO3) 240 (as CaCO3) Current Permit Receiving Water Hardness 90 (as CaCO3) 90 (as CaCO3) Current Permit Receiving Water pH 8.26 8.26 Current Permit Effluent pH (5-year Max) 8.40 8.26 DMRs Effluent Flow Rate (Max. Day) 0.39 cfs 0.69 MGD (1.07 cfs) Wastewater Facility Plan Effluent Flow Rate (Max. Mo.) 0.27 cfs 0.29 MGD (0.45 cfs) Wastewater Facility Plan Receiving Water 7Q10 Flow 300 cfs 300 cfs Current Permit

Receiving Water Depth 1.5 ft to outfall invert; 7.5 ft total 7.5 ft Current Permit

Receiving Water Width 180 ft 180 ft Current Permit Receiving Water Velocity 0.22 ft/s 0.22 ft/s Current Permit Receiving Water Channel Manning Roughness 0.033 0.033 Current Permit

Receiving Water Channel Slope (ft/ft) 0.00088 0.00088 Current Permit

Chronic Dilution Factor 122.1 24.5 CORMIX v.6.0.0.0 Acute Dilution Factor 20.2 15.7 CORMIX v.6.0.0.0

Chronic Mixing Zone 31.15 feet wide by 300 feet long

31.15 feet wide by 300 feet long Current Permit

Acute Mixing Zone 9.85 feet wide by 30 feet long

9.85 feet wide by 30 feet long Current Permit

Mixing Zone Dilution Factors It was determined that the City use CORMIX modeling software to accurately model the outfall’s behavior. The purpose of the CORMIX model is to determine dilution factors that will be used to predict effluent permit limits for pH and ammonia. The resulting dilution factors, obtained from CORMIX, were 15.7 and 24.5 for acute and chronic conditions, respectively. The input and output for both model runs are included at the end of this appendix. PROJECTED PERMIT LIMITS Projected effluent permit limits for BOD5, TSS, fecal coliform, pH, dissolved oxygen, ammonia, residual chlorine, temperature, and priority pollutants were determined below using the dilution factor approach in addition to technology-based criteria. The projected effluent limits are summarized in Table C-3.



TABLE C-3 City of Mabton WWTF

Future Projected NPDES Permit Effluent Limits


BOD5 N/A 10 mg/L or 15% of Influent concentration 15 mg/L

TSS N/A 30 mg/L or 15% of Influent concentration 45 mg/L


pH Within the range 6-9 Within the range 6-9 Within the range 6-9


Total Ammonia (as NH3-N) 4.5 mg/L 2.3 mg/L N/A

BOD5 and Dissolved Oxygen The Mabton WWTF discharges into a segment of the Yakima River that is listed as impaired for dissolved oxygen, and as a result, a mixing zone is not authorized for BOD5 or dissolved oxygen. The impact of low dissolved oxygen in the effluent was modeled in the NPDES permit utilizing EPA methods and a dilution factor of one. The City of Mabton is required by its NPDES permit to identify and evaluate methods to increase dissolved oxygen in the effluent as part of the plan to maintain capacity, which is addressed in Chapter 6 of this Wastewater Facility Plan

. Due to the Yakima River’s impaired listing for dissolved oxygen, it is projected that the existing minimum dissolved oxygen limits of 4 mg/L average monthly and 3 mg/L daily will remain in effect.

Fecal Coliform A mixing zone cannot be authorized for fecal coliform because the lower Yakima River is listed as impaired for fecal coliform under critical conditions. Because there is no mixing zone allowed for the discharge, the technology-based limit would result in violations of the fecal coliform criterion for the receiving water. An effluent limit equal to the water quality criteria (100 colonies/100 mL) was therefore imposed during the issuance of the current NPDES permit. It is projected that the limits will most likely remain the same as those in the current NPDES permit.



TSS Effluent limitations for TSS are set by federal and state regulations (40 CFR Part 133 and WAC 173-221). These technologically-based limits are expected to remain the same for the facility as long as the treatment method does not change. Therefore, since the Mabton WWTF will continue to utilize an oxidation ditch activated sludge process as detailed in Chapter 5 of this Wastewater Facility Plan

, the projected limits will most likely remain the same as those in the current NPDES permit.

pH Water quality criteria were determined for pH using the spreadsheet, PHMIX2, provided by Ecology in the workbook PWSPREAD. Using the technology based limits of 6-9 standard units, the resulting pH range at the edge of the mixing zone was determined to be between 7.5 and 8.26, which meets the criteria for the Yakima River as described in Table C-1. Ammonia Water quality criteria were determined for ammonia using the Excel workbook TDSCALC20101108, provided by Ecology. The Ecology workbook utilizes user input values to perform calculations per the procedure outlined in Technical Support Document for Water Quality-Based Toxics Control

(EPA, March 1991) page 56. To summarize the procedure, background information for the Yakima River (temperature and pH) is input into the NH3FRESH3.XLS spreadsheet to determine what the total ammonia nitrogen criteria for the water body is, as temperature and pH affect the ionization and toxicity of ammonia. The total ammonia nitrogen criteria for the water body is the state water quality standard that cannot be exceeded at the edge of the mixing zones. For the Mabton outfall, these values were determined to be 3,404 µg/L for the acute condition and 429 µg/L for the chronic condition.

After determining the water quality standards, the REASPOT.XLS spreadsheet in the workbook was used to perform the statistical analysis necessary for determining if there is a reasonable potential (95 percent confidence interval) for the Mabton WWTF to violate the water quality standards. This calculation is based upon the acute and chronic dilution factors determined by the CORMIX model, the maximum measured historical effluent ammonia concentration (39.6 mg/L in May 2009), the number of ammonia samples used (72 DMR measurements), and ambient Yakima River ammonia concentration (0.33 mg/L NH3-N per NPDES permit fact sheet). It was determined that there is a reasonable potential for the Mabton WWTF effluent to violate the water quality standards, which is supported by the City’s NPDES permit limit for ammonia. Once it was determined that there is reasonable potential to violate water quality standards, LIMIT.XLS in the workbook was used to determine what NPDES permit limit is required. The spreadsheet calculates permit limits based on the procedure and



calculations in Technical Support Document for Water Quality-Based Toxics Control

page 99. The City of Mabton’s projected ammonia discharge NPDES permit limits using this method are 2.3 mg/L on an average monthly basis and 4.5 mg/L on a maximum daily basis.

Residual Chlorine At this time the treatment facility does not utilize chlorine disinfection. Therefore, no effluent chlorine limit is projected for the future. Temperature The river segment that the Mabton WWTF discharges to is listed as impaired for temperature. Because of the need to reduce temperatures from all sources, a future Yakima River basin temperature TMDL study may determine a temperature waste load allocation (WLA) for the Mabton WWTF for protection of water quality in the Yakima River. Therefore, the City is required in its current NPDES permit to include options to lower the effluent temperature, as addressed in Chapter 6 of this Wastewater Facility Plan

.

The lower Yakima River temperature water quality standard is 21.0oC, as shown in Table C-1. However, as shown in Table C-2, the natural temperature of the Yakima River during the critical period is projected to be greater than 21.0oC. When natural temperatures exceed 21.0oC, effluent temperatures raising the temperature by greater than 0.3oC are not allowed. The 7Q10 flow in the Yakima River of 300 cfs is approximately 280 times greater than the maximum day effluent flow from the Mabton WWTF. Using a flow-weighted average, no violations of the temperature criteria are predicted from the discharge during critical conditions.

Max Day Flow (Acute) CORMIX Modeling Run

Max Month Flow (Chronic) CORMIX Modeling Run

APPENDIX D

COST ESTIMATES

NO. ITEM Quantity Unit Unit Price Amount1 Mobilization 1 LS 274,000$ $274,000

2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000

5 Aeration Basin/Oxidation Ditch Improvements 1 LS 749,000$ $749,000

6 Secondary Clarifier 1 LS 398,000$ $398,000

7 Sludge Pumping Modifications 1 LS 70,000$ $70,000

8 UV Disinfection System 1 LS 178,000$ $178,000

9 Effluent Pumping 1 LS 26,000$ $26,000

10 Effluent Aeration 1 LS 36,000$ $36,000

11 Aerobic Sludge Storage Tank Modifications 1 LS 29,000$ $29,000

12 Sludge Drying Beds 1 LS 237,000$ $237,000

13 Plant Drain Lift Station 1 LS 120,000$ $120,000

14 Non Potable Water 1 LS 42,000$ $42,000

15 Electrical 1 LS 400,000$ $400,000

16 Diesel Generator 1 LS 80,000$ $80,000

17 Lab and Maintenance Modifications 1 LS 40,000$ $40,000

18 SCADA Modifications 1 LS 35,000$ $35,000

19 Site Piping 1 LS 264,000$ $264,000

20 Asphalt repair 1 LS 47,000$ $47,000

Subtotal: $3,314,000

Construction Contingency (25%): $829,000

Construction Subtotal $4,143,000

Washington State Sales Tax (7.9%) $327,000

Construction Total: $4,470,000

Land Purchase $50,000

Design & Construction Engineering (25%): $1,118,000

Total Estimated Project Cost: $5,638,000

CITY OF MABTON

WWTF FACILITY PLAN

WWTF AERATION ALTERANTIVE NO. 1

New Aeration Basin with Bioselectors and Anoxic Basin, Existing Oxidation Ditch


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000

5 Aeration Basin/Oxidation Ditch Improvements 1 LS 1,086,000$ $1,086,000










15 Electrical 1 LS 400,000$ $400,000




19 Site Piping 1 LS 264,000$ $264,000










CITY OF MABTON

WWTF FACILITY PLAN


New Aeration Basin with Bioselectors and Anoxic Zone


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000











15 Electrical 1 LS 400,000$ $400,000




19 Site Piping 1 LS 264,000$ $264,000









CITY OF MABTON

WWTF FACILITY PLAN


New Aeration Basin With Bioselectors, Oxidation Ditch with Anoxic Cycle


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 279,000$ $279,000

5 Membrane Equipment 1 LS 1,414,500$ $1,414,500

6 Membrane Basin and Blowers 1 LS 350,000$ $350,000

7 Membrane Building 1 LS 150,000$ $150,000









16 Electrical 1 LS 425,000$ $425,000




20 Site Piping 1 LS 264,000$ $264,000



Construction Contingency (25%): $1,069,000







WWTF FACILITY PLAN


Membrane Bioreactor

CITY OF MABTON


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks (Parshall Flume) 1 LS 20,000$ $20,000

5 Recirculating Tank 1 LS 350,000$ $350,000

6 RGF 1 LS 2,750,000$ $2,750,000

7 Interceptor Tanks and Site Resotration 560 EA 3,000$ $1,680,000




11 Electrical 1 LS 250,000$ $250,000



14 Site Piping 1 LS 150,000$ $150,000










CITY OF MABTON

WWTF FACILITY PLAN


Reciriculating Gravel Filter With Interceptor Tanks


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000

5 Recirculating Tank 1 LS 350,000$ $350,000

6 RGF 1 LS 2,750,000$ $2,750,000

7 Clarifier Modifications 1 LS 300,000$ $300,000

8 Aerobic Tank Modifications 1 LS 200,000$ $200,000






13 Electrical 1 LS 250,000$ $250,000



16 Site Piping 1 LS 150,000$ $150,000











Reciriculating Gravel Filter With Primary Clarifier

CITY OF MABTON

WWTF FACILITY PLAN


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000


6 Secondary Clarifier Modifications 1 LS 398,000$ $398,000






12 Mechanical dewatering 1 LS 447,000$ $447,000



15 Electrical 1 LS 450,000$ $450,000




19 Site Piping 1 LS 294,000$ $294,000









CITY OF MABTON

WWTF FACILITY PLAN

WWTF MECHANCIAL DEWATERING

TOTAL ESTIMATED PROJECT COST


2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 249,000$ $249,000


6 Secondary Clarifier Modifications 1 LS 398,000$ $398,000







13 Plant Drain Lift Station 1 LS $0


15 Electrical 1 LS 400,000$ $400,000

16 Diesel Generator 1 LS 80,000$ 80,000$



19 Site Piping 1 LS 264,000$ $264,000









CITY OF MABTON

WWTF FACILITY PLAN

SLUDGE DRYING BED ALTERNATIVE NO DRAINS



2 Trench Safety 1 LS 20,000$ $20,000

3 SPCC Plan 1 LS 20,000$ $20,000

4 Headworks 1 LS 264,000$ $264,000

5 Faculative Lagoon 20 AC 150,000$ $3,000,000

6 Wetland 8 AC 150,000$ $1,200,000

7 Polishing Process 0.5 AC 150,000$ $75,000

8 Recycle Pump Station 1 LS 65,000$ $65,000

9 MBBR-denitrification 1 LS 195,000$ $195,000

10 Groundwater Monitoring 1 LS 200,000$ $200,000




14 Site Fencing 5000 LF 20$ $100,000

15 Access Roads (gravel) 600 TN 30$ $18,000

16 Electrical 1 LS 100,000$ $100,000


18 Site Piping 1 LS 100,000$ $100,000









ALT. 7 - NATURAL WASTEWATER TREATMENT


CITY OF MABTON

WWTF FACILITY PLAN


2 Polymer Equipment 1 LS 84,000$ $84,000

3 Filtration Equipment 1 LS 335,000$ $335,000

4 Tanks 1 LS 35,000$ $35,000

5 Building 1 LS 380,000$ $380,000

6 Pump Station 1 LS 152,000$ $152,000

7 UV System Improvements 1 LS 190,000$ $190,000

8 Storage Ponds 1 LS 2,425,000$ $2,425,000

9 Additional Land Purchase 1 LS 300,000$ $300,000


11 Bypass Valves and Piping 1 LS 53,000$ $53,000

12 Reclaimed Water Pump Station 1 LS 189,000$ $189,000

13 Reclaimed Water Pipeline 10,000 LF 65$ $650,000

14 Electrical 1 LS 250,000$ $250,000








CITY OF MABTON

WATER RECLAIMATION IMPROVEMENTS


WWTF FACILITY PLAN

APPENDIX E

ENVIRONMENTAL REPORTS NEPA & SEPA

Environmental Report 1 City of Mabton Wastewater Facility Plan

NEPA ENVIRONMENTAL REPORT

WASTEWATER FACILITY PLAN

CITY OF MABTON


CHAPTER 1

PURPOSE AND NEED


1.0 PURPOSE AND NEED The source of most of the information for this chapter is the Wastewater Facility Plan prepared for the City of Mabton by Gray & Osborne, Inc. (2011).

1.1 Project Description (Proposed Action or Proposed Project)

The Wastewater Facility Plan addresses the City of Mabton’s comprehensive planning needs for wastewater treatment and disposal for the next 20 years. The Plan is intended to be feasible in terms of engineering, economic, regulatory, and political frameworks. The Plan proposes upgrading the City’s Wastewater Treatment Facility (WWTF). The City is planning on construction of one of two alternatives; WWTF improvements with either a sludge drying bed alterative or a mechanical dewatering alternative. Figures showing the schematic layout of the alternatives are attached. The sludge drying bed alterative will require land purchase while the other alternative will not. If the City can purchase the land, the City will construct the sludge drying bed alternative. Both alternatives are similar and both are described below. The WWTF improvements will consist of the following at the existing site of the WWTF:

Construction of new headworks

Construction of new aerobic basin with bioselectors

Construction of a new secondary clarifier with retaining wall along Vance Road

Replacement of ultraviolet disinfection system inside of existing building

Replacement of effluent pumps inside of existing structure

Construction of a new effluent aeration manhole

Construction of new sludge drying beds or construction of mechanical dewatering building

Modifications to existing secondary clarifier, aerobic sludge holding tank and laboratory building

Piping and electrical improvements

1.2 Purpose and Need for the Project The existing WWTF is at 85 percent capacity and the City’s NPDES permit requires the City to complete a plan for adequate capacity (PMAC). The City completed a Wastewater Facility Plan (a PMAC). The Wastewater Facility Plan in conjunction with the City’s Comprehensive Plan determined that the existing population is 2,165 and is projected to grow to 3,031 by 2031 (the twenty year planning period). The WWTF must be expanded to handle the population growth and to maintain adequate wastewater treatment. In addition, proposed lower permit limits for ammonia will require improvements to the WWTF processes. A more comprehensive analysis of the WWTF is included in Chapter 5 of this Plan. The analysis includes a treatment capacity analysis based on the 20-year projected flows and loadings.


CHAPTER 2

ALTERNATIVES TO THE PROPOSED ACTION


2.0 ALTERNATIVES TO THE PROJECT ACTION Alternative 1: No Action: Alternative 2: Activated Sludge process improvements to the WWTF: Alternative 3: Membrane Bioreactor process improvements to the WWTF: Alternative 4: Recirculating Gravel Filter process improvements to the WWTF: 2.1 Screening Evaluation

Alternative 1: No Action: Taking no action to expand the Waste Water Treatment Facility would result in the existing WWTF reaching capacity and would prevent the City from growing in population. In addition the City would begin to violate new proposed ammonia limits and could violate effluent oxygen limits. Alternative 2: Activated sludge process improvements at the WWTF: This alternate would expand the activated sludge process at the WWTF. Advantages of this alternative:

This alternative would expand the capacity of the WWTF by increasing the capacity of the existing activated sludge process at the WWTF. The proposed improvements will meet lower ammonia discharge limits, remove nitrogen, and allow the WWTF to consistently meet its effluent oxygen limits. The WWTF would have the capacity to be upgraded to meet possible future phosphorus limits.

Disadvantages of this alternative include:

None.

Alternative 3: Membrane Bioreactor Improvements to the WWTF: This alternative would replace the activated sludge process at the WWTF with a membrane bioreactor. Advantages of this alternative:

This alternative would produce a higher quality effluent.



This alternative has significantly higher capital and operation and maintenance cost than the other alternatives.

Alternative 4: Recirculating Gravel Filter improvements to the WWTF: This alternative would replace the activated sludge process at the WWTF with a recirculating gravel filter. Advantages of this alternative:

Has the lowest energy cost and operation and maintenance cost of all other alternatives.


This alternative will not meet ammonia or nitrogen permit limits in the winter months. This alternative has significantly higher capital cost than all of the other alternatives, which will require the highest rate increases.

Findings Alternative 2 provides the means which will allow the City of Mabton to grow in population while meeting the current and future permit limits at the least overall cost. The following Alternative Analysis will examine the environmental consequences associated with construction and operation of the proposed activated sludge process improvements at the Mabton WWTP, comparing the sludge drying bed (Alterative 2) and the mechanical dewatering (Alternative 3) processes.


CHAPTER 3

AFFECTED ENVIRONMENT/ ENVIRONMENTAL CONSEQUENCES


3.0 Affected Environment/Environmental Consequences 3.1 Land Use/Important Farmland/Formally Classified Lands (Farmland Protection Policy)

3.1.1 Affected Environment

The City of Mabton and its UGA are located in Yakima County, approximately 40 miles southeast of the City of Yakima. The land in and around the City is located near the floodplain of the Yakima River, at an approximate altitude of 718 feet above sea level. The lands surrounding the City of Mabton and its associated UGA are primarily irrigated agricultural lands. These lands are irrigated from a system of canals and ditches with flow from the nearby Yakima River. The land designated for use in the eventual expansion of the Wastewater Treatment Facility is not designated as prime farmland. In addition, the relatively small amount of land being utilized is not significant enough to cause any measurable impact to the total output of agriculture in the area.

3.1.2. Environmental Consequences Alternative 1: No Action Taking No Action to improve the Mabton WWTP would eventually result in the facilities being unable to meet the wastewater treatment requirements in the City’s National Pollutant Discharge Elimination System (NPDES) Permit. This could result in a moratorium on future connections and other land use restrictions for the WWTP service area. Alternative 2: Sludge Drying Beds The proposed wastewater treatment process improvements will require approximately 1.5 to 2.0 acres of farmland to be converted to WWTF if the Sludge Drying Bed alternative is constructed. The existing farmland is inside of the designated Urban Growth Area and is zoned industrial. The City and County comprehensive plans have designated this area as an area for urban growth and this farmland will be eventually converted to other uses beside farmland, whether or not this project occurs. Alternative 3: Mechanical Dewatering Implementation of the proposed WWTP improvements with mechanical dewatering would provide adequate wastewater treatment and sludge drying capacity for the Mabton service area through the 20 year planning period, but without the conversion of farmland for sludge dewatering purposes. This process will be chosen if the City is unable to purchase the required farmland for the sludge drying bed alternative.


3.1.3 Mitigation Implementation of Alternative 3 would eliminate the purchase and conversion of 1.5 to 2.0 acres of productive farmland adjacent to the Mabton WWTP. In the event that Alternative 2 is chosen, it is likely that the agency ultimately responsible for funding the project will require the Natural Resources Conservation Service to conduct a Prime Farmland Conversion Analysis.

3.2 Floodplain


According to the FEMA Flood Insurance Rate Map (FIRM Panel 530217-2276) for the City of Mabton, the WWTP is located lie outside of the 100-year flood plain of the Yakima River (see attached map). 3.2.2 Environmental Consequences Alternative 1: No Action Taking No Action to upgrade the Mabton WWTP would have no direct impact on the floodplain of the Yakima River. However, failure to upgrade the facility would eventually lead to overloading of the WWTP, discharge of substandard effluent and contamination of the Yakima River floodplain. Alternative 2: Sludge Drying Beds Upgrading the Mabton WWTP activated sludge process and using drying beds for sludge dewatering would require the purchase of farmland adjacent to the WWTP. Provided these sludge drying beds are located outside of the 100-year floodplain of the Yakima River, the project would be unlikely to significantly impact flooding. Alternative 3: Mechanical Dewatering Upgrading the Mabton WWTP using mechanical sludge dewatering within the confines of the existing site would have no impact on the 100-year floodplain of the Yakima River. 3.2.3 Mitigation In the event that the sludge drying beds were located within the 100-year floodplain, flood proofing would likely be required if federal funding is used to finance the improvements.


3.3 Wetlands 3.3.1 Affected Environment There are no formally classified wetlands within the immediate area of the WWTF improvements. Soils in the vicinity of the WWTF project are Warden silt loam, Umapine silt loam, and Esquatzel silt loam. These soils are generally well drained and are not wetland soils. See NRCS Soils map attachment and Wetlands map attachment. 3.3.2 Environmental Consequences None 3.3.3 Mitigation

No impacts to mitigate at this time.

3.4 Cultural Resources


According to City officials and preliminary observations of the project site, there appear to be no landmarks or evidence of historic, archaeological, scientific or cultural importance known to be on or next to the proposed project sites. Dr. Robert Whitlam of the Washington State Department of Archeological and Historic Preservation was contacted regarding the potential for archaeological and historically significant resources in the project area. Dr. Whitlam stated that Section 106 processes would only be required prior to proposed construction activities and were not necessary during the planning stages. 3.4.2 Environmental Consequences

The project, as proposed, should have no adverse impacts on cultural/archaeological resources provided the appropriate mitigation measures summarized below are implemented during construction. 3.4.3 Mitigation During construction, any excavation by the Contractor that uncovers a historical or archaeological artifact shall be immediately reported to the Project Engineer, a representative of funding agency, and the associated Native American Tribes. Construction shall be temporarily halted pending the notification process and further directions issued by funding agency after consultation with the


Department of Archeological and Historic Preservation Officer and the appropriate Tribal Officials.

3.5 Biological Resources

3.5.1 A. Threatened & Endangered Species Affected Environment

According to the Washington State Fish and Wildlife Priority Habitat and Species list (see attached), there are no listed Endangered or Threatened Species in the immediate project vicinity. The nearest listed species, the Townsend’s Ground Squirrel occurs more than one mile to the southwest of the project. The proposed project area is located near the Yakima River. There are several listed species that may utilize the Yakima River and the surrounding riparian environment, however the project lies more than 200 feet from the river and the project will for this reason, it is unlikely to impact these species. The following list, as downloaded from the Fish and Wildlife Service website, identifies endangered, threatened, and species of concern potentially present in Yakima County.

Yakima COUNTY Updated 12/15/2010

LISTED

Bull trout (Salvelinus confluentus) – Columbia River DPS, Threatened Gray wolf (Canis lupus) Endangered Grizzly bear (Ursus arctos horribilis) Endangered Marbled murrelet (Brachyramphus marmoratus) Threatened Northern spotted owl (Strix occidentalis caurina) Threatened Spiranthes diluvialis (Ute ladies’-tresses) Threatened

DESIGNATED

Critical habitat for the bull trout Critical habitat for the northern spotted owl CANDIDATE

Fisher (Martes pennanti) - West Coast DPS Greater sage grouse (Centrocercus urophasianus) – Columbia Basin DPS Mardon skipper (Polites mardon) North American wolverine (Gulo gulo luteus) – contiguous U.S. DPS Yellow-billed cuckoo (Coccyzus americanus)

SPECIES OF CONCERN

Bald eagle (Haliaeetus leucocephalus) Black swift (Cypseloides niger) Burrowing owl (Athene cunicularia) Ferruginous hawk (Buteo regalis) Larch Mountain salamander (Plethodon larselli) Loggerhead shrike (Lanius ludovicianus)


Long-eared myotis (Myotis evotis) Northern goshawk (Accipiter gentilis) Olive-sided flycatcher (Contopus cooperi) Pacific lamprey (Lampetra tridentata) Pallid Townsend's big-eared bat (Corynorhinus townsendii pallescens) Peregrine falcon (Falco peregrinus) Redband trout (Oncorhynchus mykiss) River lamprey (Lampetra ayresi) Sagebrush lizard (Sceloporus graciosus) Sharptail snake (Contia tenius) Townsend’s ground squirrel (Spermophilis townsendii) Western brook lamprey (Lampetra richardsoni) Western gray squirrel (Sciurus griseus griseus) Westslope cutthroat trout (Oncorhynchus clarki lewisi) Astragalus columbianus (Columbia milk-vetch) Calochortus longebarbatus var. longebarbatus (long-bearded sego lily) Castilleja cryptantha (obscure paintbrush) Cryptantha leucophaea (gray cryptantha) Cypripedium fasciculatum (clustered lady’s-slipper) Erigeron basalticus (basalt daisy) Lomatium tuberosum (Hoover’s desert-parsley) Pinus albicaulis (whitebark pine) Sisyrinchium sarmentosum (pale blue-eyed grass) Tauschia hooveri (Hoover’s tauschia)

Note: See attached species list National Marine Fisheries Service list the following as endangered or threatened species for the Columbia River. The Yakima River is a tributary to the Columbia River therefore these fish might be found in the Yakima River. No construction work will be performed in the Yakima River therefore construction will not impact these species. Operation of the upgraded WWTP under either construction alternative would improve and maintain water quality Section 3.6 Water Quality will discuss the WWTF discharge to the Yakima River.

Endangered - Upper Columbia River Spring Run Chinook Salmon

Threatened –Columbia River Chum Salmon

Threatened – Upper, Lower and Middle Columbia River Steelhead

Note: See attached species lists


3.5.1 B. Fish & Wildlife

The project lies greater than 200 feet from the edge of any waters, so impacts to fish and aquatic wildlife are not anticipated at this time. Wildlife with the potential to be present in the project area includes amphibians such as salamanders and toads, reptiles such as turtles and snakes, birds such as falcons, eagles, grouse, owls, woodpeckers, and various species of waterfowl. Mammals potentially inhabiting the area include squirrels and canine species such as coyote. There are also several species of bats which may utilize the area for nesting and foraging. Possible impacts to fish and wildlife may result only during the construction stages and will not be long term effects.

Some of the proposed improvements to the Mabton sewer collection and treatment system will take place in areas occasionally supporting habitat for wildlife. Construction best management practices (BMPs) for the control of erosion and sedimentation and noise will be implemented. Therefore, the construction of the proposed improvements will have little immediate effect on the listed species of wildlife utilizing the area and no lasting adverse effects.

3.5.1 C. Vegetation

The improvements will occur at the existing WWTF and on farmland to the West. The existing WWTF area is 100 percent impervious area and vegetation in this area will not be affected. The expansion will utilize land that is 100 percent farmed and no endangered, listed or candidate species are expected.

3.5.2 Environmental Consequences

Alternative 1: No Action Taking No Action to upgrade the Mabton WWTP would result in eventual over-loading of the facility’s capacity and discharge of effluent that does not meet the requirements of the NPDES Permit. Unpermitted pollution of critical habitat for listed salmonids would constitute “take” of these species in violation of Section 7 of the Endangered Species Act of 1973.

Action Alternatives


Construction and operation of the proposed wastewater treatment plant upgrades will ensure compliance with the Mabton WWTP’s NPDES Permit through the planning period, which should protect listed salmonids present in the Yakima River near the outfall

3.6 Water Quality

3.6.1 Affected Environment Surface Water:

The City of Mabton is located near the Yakima River. The WWTF treated effluent discharges to the Yakima River. Department of Ecology (WAC 173-201A-602) list the Yakima River for spawning and rearing of aquatic life. Based on the aquatic life use of the Yakima River water quality criteria for the Yakima River have been determined for the Yakima River at the Mabton WWTP outfall. Outfall modeling was completed as part of the WWTF Plan. The outfall modeling determined that ammonia permit limits for the WWTF must be lowered to meet the Yakima River water quality criteria. Groundwater: Groundwater near the Mabton WWTP can occur near the surface during the growing season when irrigation occurs nearby. 3.6.2 Environmental Consequences Alternative 1: No Action Taking No Action to improve wastewater treatment capacity at the Mabton WWTP would eventually result in discharge of effluent that does not meet NPDES Permit requirements, which could result in adverse impacts to water quality and aquatic habitat. It could eventually lead to a connection moratorium and other land use restrictions in Mabton. Action Alternatives Surface Water The WWTF improvements will enable the WWTF to meet more stringent ammonia limits. In addition, the WWTF improvements will enable the WWTF to meet current NPDES discharge limits, reliably meet oxygen limits, and will remove nitrogen, which might become a limited water quality parameter in future permits. Either treatment process selected for the WWTF improvements can be upgraded in the future for phosphorus removal, which might also become a regulated parameter in future permits.


The outfall modeling conducted in has shown that the existing discharge meets the water quality criteria for the Yakima River. The water quality criteria for the Yakima River currently protect aquatic life, including listed salmonids. The proposed improvements to the wastewater treatment processes will be designed to produce effluent consistent with foreseeable NPDES Permit Limits, which should protect listed salmonids as the population grows over the next 20 years. Groundwater Construction of some of the deeper excavations might require dewatering. Water removed from trenches would be directed to open fields nearby and allowed to infiltrate. Water quality in the Yakima River is unlikely to be affected.

3.6.3 Mitigation

Construction best management practices shall be implemented to minimize the potential for generation of sediment-laden runoff from the construction areas during dewatering.

3.7 Coastal Resources


The proposed project is located in the Yakima River Valley more than 250 river miles upstream of the Pacific Ocean and therefore will have no impact on coastal lands. 3.7.2 Mitigation No mitigation measures required.

3.8 Socioeconomic/Environmental Justice


Demographics The approximate total population of the City of Mabton is 2,165 people and is projected to grow to 3,031 during the twenty year planning period. Currently the City has a Low to Moderate Income population of 66.9%. Employment The Mabton economy has historically been based on agriculture.


3.8.2 Environmental Consequences Alternative 1: No Action Without a wastewater system capable of providing adequate treatment of sewage required by the City’s businesses, industries, and residents, the City will suffer greatly both socially and economically. Without the improvements, the City will not be able to grow in population. Action Alternatives The proposed project would be a direct benefit to a large portion of the low to moderate income citizens as well as the businesses and industries owned by and employing the citizens of Mabton. The .

3.8.2 Environmental Justice Issues

Rate impacts associated with proposed improvements to the Mabton WWTP and associated infrastructure have the potential to adversely impact minority and low-income populations in the service area. The City of Mabton will actively pursue grants and low-interest loans to minimize rate increases required to upgrade the WWTP and their potential disproportionate adverse impacts on minority and low-income populations.

3.8.3 Mitigation

The City will seek grants and low interest loans to mitigate the high costs of the project on the low income families of the City. Implementation of either the proposed project action alternatives will improve the existing system capacity to meet future demands and permit limits.

3.9 Miscellaneous Issues 3.9.1 Air Quality - Affected Environment

Air Quality in the vicinity of Mabton is generally good. The construction activities associated with the proposed projects include minimal dust and vehicle pollution.

3.9.1.1 Air Quality-Environmental Consequences

Alternative 1: No Action Taking No Action to upgrade the Mabton WWTP would eventually result in overloading of the facility with the potential for odor problems.


Action Alternatives: Is one sludge handling alternative smellier than the other? If so we could discuss it here. Emissions to the air associated with the proposed WWTP improvements will be temporary. Potential sources of emissions would include exhaust fumes from construction equipment and fugitive dust associated with construction activities. Once construction is complete, air quality will return to normal with no lasting effects.

3.9.1.2 Air Quality - Mitigation

Watering of particularly dusty areas and activities during construction will be the primary dust control measure during ground disturbing activities. Construction vehicles will be properly operated and maintained, such that vehicle emissions will be at such a minimal level, requiring no mitigation.

3.9.2 Transportation-Affected Environment The City of Mabton is accessed from the west and east via State Highway 241 and 22. Construction of the proposed improvements will have a minimal increase in large vehicle traffic to the site during construction activity. Once construction is complete and the improvements are in operation, no increase in traffic over existing conditions is anticipated. 3.9.3 Noise Noise associated with construction vehicles and equipment will be present in the project area during construction activities. Once construction is complete, noise levels will return to pre-construction levels, as any new noise-generating equipment (pumps, blowers etc.) involved in the project will be isolated and are unlikely to be detectable off-site. In order to reduce the impact of construction noise on wildlife and the population in adjacent areas, construction activities will occur only between the hours of 7:00 am and 7:00 pm.


4.0 Summary of Mitigation This environmental report concludes that impacts to the human environment as a result of this project and mitigation for these impacts include: a) Construction shall take place during the dry season and construction best

management practices shall be implemented to minimize the potential for generation of sediment-laden runoff from the project site.

b) Financial impacts to low income populations shall be mitigated through the

acquisition of grants and low-interest loans; c) Noise impacts shall be addressed by limitation of hours of construction. d) During construction, any excavation by the Contractor that uncovers a historical

or archaeological artifact shall be immediately reported to the Project Engineer, a representative of funding agency, and the associated Tribe(s). Construction shall be temporarily halted pending the notification process and further directions issued by the funding agency after consultation with the Department of Archeological and Historic Preservation Officer and appropriate Tribal Officials.


5.0 Correspondence See Attachments


6.0 Exhibits See Attachments

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Soil Map—Yakima County Area, Washington

Natural ResourcesNatural ResourcesNatural ResourcesNatural ResourcesConservation ServiceConservation ServiceConservation ServiceConservation Service

Web Soil SurveyNational Cooperative Soil Survey

12/28/2010Page 1 of 3

MAP LEGEND MAP INFORMATION

Area of Interest (AOI)Area of Interest (AOI)

SoilsSoil Map Units

Special Point FeaturesBlowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line FeaturesGully

Short Steep Slope

Other

Political FeaturesCities

Water FeaturesOceans

Streams and Canals

TransportationRails

Interstate Highways

US Routes

Major Roads

Local Roads

Map Scale: 1:2,460 if printed on A size (8.5" × 11") sheet.

The soil surveys that comprise your AOI were mapped at 1:24,000.

Please rely on the bar scale on each map sheet for accurate mapmeasurements.

Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL: http://websoilsurvey.nrcs.usda.govCoordinate System: UTM Zone 11N NAD83

This product is generated from the USDA-NRCS certified data as ofthe version date(s) listed below.

Soil Survey Area: Yakima County Area, WashingtonSurvey Area Data: Version 10, Jun 12, 2009

Date(s) aerial images were photographed: 7/1/2006

The orthophoto or other base map on which the soil lines werecompiled and digitized probably differs from the backgroundimagery displayed on these maps. As a result, some minor shiftingof map unit boundaries may be evident.

Soil Map–Yakima County Area, Washington

Natural ResourcesConservation Service


12/28/2010Page 2 of 3

Map Unit Legend

Yakima County Area, Washington (WA677)

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

32 Esquatzel silt loam, 0 to 2 percent slopes 4.3 18.7%

58 Hezel loamy fine sand, 2 to 15 percentslopes

1.7 7.2%

169 Umapine silt loam, drained, 0 to 2 percentslopes

6.4 27.9%

172 Warden fine sandy loam, 0 to 2 percentslopes

0.8 3.3%

177 Warden silt loam, 2 to 5 percent slopes 9.8 42.9%

Totals for Area of Interest 22.9 100.0%




12/28/2010Page 3 of 3

Endangered Species Act Status of West Coast Salmon & Steelhead (Updated July 1, 2009)

Species1

Current Endangered Species Act

Listing Status2

ESA Listing Actions Under Review

Sockeye Salmon (Oncorhynchus nerka)

1 Snake River Endangered

2 Ozette Lake Threatened

3 Baker River Not Warranted

4 Okanogan River Not Warranted

5 Lake Wenatchee Not Warranted

6 Quinalt Lake Not Warranted

7 Lake Pleasant Not Warranted

Chinook Salmon (O. tshawytscha)

8 Sacramento River Winter-run Endangered

9 Upper Columbia River Spring-run Endangered 10 Snake River Spring/Summer-run Threatened 11 Snake River Fall-run Threatened 12 Puget Sound Threatened 13 Lower Columbia River Threatened 14 Upper Willamette River Threatened 15 Central Valley Spring-run Threatened 16 California Coastal Threatened 17 Central Valley Fall and Late Fall-run Species of Concern 18 Upper Klamath-Trinity Rivers Not Warranted

19 Oregon Coast Not Warranted

20 Washington Coast Not Warranted

21 Middle Columbia River spring-run Not Warranted

22 Upper Columbia River summer/fall-run Not Warranted

23 Southern Oregon and Northern California Coast Not Warranted

24 Deschutes River summer/fall-run Not Warranted

Coho Salmon (O. kisutch)

25 Central California Coast Endangered

26 Southern Oregon/Northern California Threatened

27 Lower Columbia River Threatened • Critical habitat

28 Oregon Coast Threatened

29 Southwest Washington Undetermined

30 Puget Sound/Strait of Georgia Species of Concern

31 Olympic Peninsula Not Warranted

Chum Salmon (O. keta)

32 Hood Canal Summer-run Threatened

33 Columbia River Threatened

34 Puget Sound/Strait of Georgia Not Warranted

35 Pacific Coast Not Warranted

Steelhead (O. mykiss)

36 Southern California Endangered

37 Upper Columbia River Threatened

38 Central California Coast Threatened

39 South Central California Coast Threatened

40 Snake River Basin Threatened

41 Lower Columbia River Threatened

42 California Central Valley Threatened

43 Upper Willamette River Threatened

44 Middle Columbia River Threatened

45 Northern California Threatened

46 Oregon Coast Species of Concern

47 Southwest Washington Not Warranted


49 Puget Sound Threatened • Critical habitat

50 Klamath Mountains Province Not Warranted Pink Salmon (O. gorbuscha)

51 Even-year Not Warranted

52 Odd-year Not Warranted

1 The ESA defines a “species” to include any distinct population segment of any species of vertebrate fish or wildlife. For Pacific salmon, NOAA

Fisheries Service considers an evolutionarily significant unit, or “ESU,” a “species” under the ESA. For Pacific steelhead, NOAA Fisheries Service has delineated distinct population segments (DPSs) for consideration as “species” under the ESA.

LISTED AND PROPOSED ENDANGERED AND THREATENED SPECIES AND CRITICAL HABITAT; CANDIDATE SPECIES; AND SPECIES OF CONCERN

IN YAKIMA COUNTY AS PREPARED BY

THE U.S. FISH AND WILDLIFE SERVICE CENTRAL WASHINGTON FIELD OFFICE

(Revised December 15, 2010)

LISTED Bull trout (Salvelinus confluentus) – Columbia River DPS Gray wolf (Canis lupus) Grizzly bear (Ursus arctos horribilis) Marbled murrelet (Brachyramphus marmoratus) Northern spotted owl (Strix occidentalis caurina) Major concerns that should be addressed in your Biological Assessment of project impacts to listed animal species include:

1. Level of use of the project area by listed species.

2. Effect of the project on listed species' primary food stocks, prey species, and foraging areas in all areas influenced by the project.

3. Impacts from project activities and implementation (e.g., increased noise levels,

increased human activity and/or access, loss or degradation of habitat) that may result in disturbance to listed species and/or their avoidance of the project area.

Spiranthes diluvialis (Ute ladies’-tresses) Major concerns that should be addressed in your Biological Assessment of project impacts to listed plant species include:

1. Distribution of taxon in the project vicinity.

2. Disturbance (trampling, uprooting, collecting, etc.) of individual plants and loss of habitat.

3. Changes in hydrology where taxon is found.

DESIGNATED Critical habitat for the bull trout Critical habitat for the northern spotted owl PROPOSED Revised critical habitat for the bull trout

CANDIDATE Fisher (Martes pennanti) - West Coast DPS Greater sage grouse (Centrocercus urophasianus) – Columbia Basin DPS Mardon skipper (Polites mardon) North American wolverine (Gulo gulo luteus) – contiguous U.S. DPS Yellow-billed cuckoo (Coccyzus americanus) SPECIES OF CONCERN Bald eagle (Haliaeetus leucocephalus) Black swift (Cypseloides niger) Burrowing owl (Athene cunicularia) Ferruginous hawk (Buteo regalis) Larch Mountain salamander (Plethodon larselli) Loggerhead shrike (Lanius ludovicianus) Long-eared myotis (Myotis evotis) Northern goshawk (Accipiter gentilis) Olive-sided flycatcher (Contopus cooperi) Pacific lamprey (Lampetra tridentata) Pallid Townsend's big-eared bat (Corynorhinus townsendii pallescens) Peregrine falcon (Falco peregrinus) Redband trout (Oncorhynchus mykiss) River lamprey (Lampetra ayresi) Sagebrush lizard (Sceloporus graciosus) Sharptail snake (Contia tenius) Townsend’s ground squirrel (Spermophilis townsendii) Western brook lamprey (Lampetra richardsoni) Western gray squirrel (Sciurus griseus griseus) Westslope cutthroat trout (Oncorhynchus clarki lewisi) Astragalus columbianus (Columbia milk-vetch) Calochortus longebarbatus var. longebarbatus (long-bearded sego lily) Castilleja cryptantha (obscure paintbrush) Cryptantha leucophaea (gray cryptantha) Cypripedium fasciculatum (clustered lady’s-slipper) Erigeron basalticus (basalt daisy) Lomatium tuberosum (Hoover’s desert-parsley) Pinus albicaulis (whitebark pine) Sisyrinchium sarmentosum (pale blue-eyed grass) Tauschia hooveri (Hoover’s tauschia)

Biological Assessment 1 City of Mabton Waste Water Treatment Facility Improvement Plan

SECTION 7

BIOLOGICAL ASSESSMENT

WASTE WATER TREATMENT

FACILITY IMPROVEMENT PLAN

CITY OF MABTON


1.0 Project Description (Proposed Action or Proposed Project)

The City of Mabton has contracted with Gray & Osborne, Inc. to prepare a Wastewater Facilities Plan required by the Washington Department of Ecology to upgrade its wastewater conveyance and treatment infrastructure. Proposed WWTF Improvements will include:

• Construction of headworks • Construction of new aerobic basin with bioselectors • Construction of a new secondary clarifier with retaining wall along Vance

Road • Replacement of ultraviolet disinfection system inside of existing building • Replacement of effluent pumps inside of existing structure • Construction of a new effluent aeration manhole • Construction of new sludge drying beds or construction of mechanical

dewatering building • Modifications to existing secondary clarifier, aerobic sludge holding tank and

laboratory building • Piping and electrical improvements

Preparation of a Biological Evaluation is required as part of the National Environmental Policy Act (NEPA)/State Environmental Review Process (SERP) that is required for the City to complete the Facilities Planning Process, which will allow the City to apply for a State Revolving Fund (SRF) financing package due to the federal seed monies associated with the SRF Program. The City is planning to construct upgrades to its existing oxidation ditch wastewater facility with the components listed above, using one of two sludge de-watering alternatives, either;

• sludge drying bed alternative on the site of adjacent farm land • mechanical dewatering alternative at the WWTF.

See attached figures for schematics of the proposed improvement alternatives. The sludge drying bed alterative would require land purchase while the on-site sludge de-watering alternative would not. If the City can purchase the land, the City will construct the sludge drying bed alternative. The WWTF will continue to discharge treated effluent meeting the City’s NPDES permit requirements to the Yakima River through the planning period (2031).


2.0 Biological Resources

2.1 Threatened & Endangered Species

The following list, as downloaded from the Fish and Wildlife Service website, identifies endangered, threatened, and species of concern potentially within Yakima County.

YAKIMA COUNTY Updated 12/15/2010 LISTED Bull trout (Salvelinus confluentus) – Columbia River Distinct Population Segment (DPS) (threatened) Gray wolf (Canis lupus) (endangered) Grizzly bear (Ursus arctos horribilis) (threatened) Marbled murrelet (Brachyramphus marmoratus) (threatened) Northern spotted owl (Strix occidentalis caurina) (threatened)

DESIGNATED Critical habitat for the bull trout Critical habitat for the northern spotted owl

PROPOSED Revised critical habitat for the bull trout

CANDIDATE Fisher (Martes pennanti) - West Coast DPS Greater sage grouse (Centrocercus urophasianus) – Columbia Basin DPS Mardon skipper (Polites mardon) North American wolverine (Gulo gulo luteus) – contiguous U.S. DPS Yellow-billed cuckoo (Coccyzus americanus)

SPECIES OF CONCERN Bald eagle (Haliaeetus leucocephalus) Black swift (Cypseloides niger) Burrowing owl (Athene cunicularia) Ferruginous hawk (Buteo regalis) Larch Mountain salamander (Plethodon larselli) Loggerhead shrike (Lanius ludovicianus) Long-eared myotis (Myotis evotis) Northern goshawk (Accipiter gentilis) Olive-sided flycatcher (Contopus cooperi) Pacific lamprey (Lampetra tridentata) Pallid Townsend's big-eared bat (Corynorhinus townsendii pallescens)


Peregrine falcon (Falco peregrinus) Redband trout (Oncorhynchus mykiss) River lamprey (Lampetra ayresi) Sagebrush lizard (Sceloporus graciosus) Sharptail snake (Contia tenius) Townsend’s ground squirrel (Spermophilis townsendii) Western brook lamprey (Lampetra richardsoni) Western gray squirrel (Sciurus griseus griseus) Westslope cutthroat trout (Oncorhynchus clarki lewisi) Plants: Astragalus columbianus (Columbia milk-vetch) Calochortus longebarbatus var. longebarbatus (long-bearded sego lily) Castilleja cryptantha (obscure paintbrush) Cryptantha leucophaea (gray cryptantha) Cypripedium fasciculatum (clustered lady’s-slipper) Erigeron basalticus (basalt daisy) Lomatium tuberosum (Hoover’s desert-parsley) Pinus albicaulis (whitebark pine) Sisyrinchium sarmentosum (pale blue-eyed grass) Tauschia hooveri (Hoover’s tauschia) The National Marine Fisheries Service lists the following as Endangered and Threatened species for the Columbia River. The Yakima River is a tributary to the Columbia River and part of the mid-Columbia River ESU, therefore these fish might be found in the Yakima River. No construction work will be performed in the Yakima River therefore construction will not impact these species. Endangered - Upper Columbia River Spring Run Chinook Salmon (O. tshawytscha) Threatened –Columbia River Chum Salmon (O. keta); the WDFW Salmonscape Application indicates that chum salmon are not present in the Yakima River and this species will not be discussed further in this report. Threatened – Upper and Middle Columbia River Steelhead (O. mykiss) Essential Fish Habitat The Magnuson-Stevens Fishery Conservation and Management Act (MSA), as amended by the Sustainable Fisheries Act of 1996, requires that projects receiving federal funding that may adversely affect Essential Fish Habitat (EFH) for commercially important species must be reviewed by the National Marine Fisheries Service. This Biological Assessment has been prepared to assess the proposed action’s likely impact on EFH for chinook and coho salmon. The WDFW Salmonscape Application indicated that pink salmon, another commercially important salmonid, are not present in the Yakima River and this species will not be discussed further in this report.


2.2 Potential for Impacts to Endangered Species

Upper Columbia River Spring Run Chinook Salmon: Upper Columbia River Spring Run Chinook salmon inhabits the Columbia River Basin, with the designated ESU boundary extending north of the Wenatchee River drainage to the Canadian Border. Upper Columbia River chinook likely stray into the Yakima River near the project area. Since the project area is adjacent to the Yakima River, the Upper Columbia River spring run chinook salmon may occur in the Yakima River waters near the project. The scope of the proposed Mabton WWTF Improvement Project for this project does not include work below the Ordinary High Water Mark or within 200 feet of the river’s edge, so construction impacts to this species are unlikely. Upgrading wastewater treatment capacity to meet NPDES Permit requirements for the next 20 years will remove ammonia and chlorine from the effluent, which will improve water quality and fisheries habitat in the Yakima River near the outfall. The proposed project will support modest growth in Mabton and the additional stormwater produced associated with the growth. The improved WWTF will serve the City’s service area through 2031. Any new development in Mabton will be required to comply with the Washington State Stormwater Manual for Eastern Washington. Due to the arid climate and permeable soils in and around Mabton, stormwater runoff from any new development in the Town is likely to infiltrate into the soil before reaching the Yakima River. Therefore, the proposed Mabton WWTF Improvement Project may affect, but is unlikely to adversely affect Upper Columbia River spring run chinook salmon. Gray Wolf (Canis lupus): The Gray wolf is found in remote parts of Western Washington with a specific designation of being west of Highway 97 and 17. The gray wolf requires large tracts of wilderness and is not likely to be present near the residential and agricultural areas surrounding Mabton. In the event that a gray wolf were to find its way to Mabton, it would be mobile enough to avoid any particularly noisy construction activities. Operation of the proposed improvements to the Mabton WWTF would improve water quality in the Yakima River near the outfall and could improve wildlife habitat as well. For these reasons, the proposed construction activities would have no effect on the gray wolf. 2.3 Potential for Impacts to Threatened Species

Grizzly Bear (Ursus arctos horribilis): According to the Grizzly Bear Recovery Plan prepared for the US Fish & Wildlife Service (2007), the grizzly bear requires large, uninterrupted tracts of land and has a propensity to avoid human contact. There are only an estimated 20 grizzly bears in Washington State and their range is limited to extreme north eastern


and north western corners of the state. For this reason, the proposed project will have no effect on the grizzly bear. Marbled murrelet (Brachyramphus marmoratus): The Marbled murrelet prefers to inhabit old growth forests within 60 miles of Puget Sound or the Pacific Ocean were it forages in coastal waters or freshwater lakes near their nesting habitat during daily feeding migrations. The proposed project site in Mabton is more than 100 miles from Puget Sound or the Pacific Ocean and there are no old growth trees in the project vicinity, so the presence of marbled murrelets in the project area is unlikely. The Mabton WWTF site and adjacent farmlands that may be utilized as the proposed sludge drying beds do not provide appropriate habitat for marbled murrelets. Therefore, the proposed project will have no effect on the marbled murrelet population. Critical Habitat: Critical Habitat for marbled murrelets is generally restricted to areas within one quarter mile of known nesting areas, which occur within 60 miles of the Puget Sound or the Pacific Ocean. As there are no known marbled murrelet nesting areas in the project area, the proposed Mabton WWTF Improvement Project will have no effect on Critical Habitat for the marbled murrelet.

Northern spotted owl (Strix occidentalis caurina): The Northern spotted owl inhabits large, undisturbed tracts of forestland. The Priority Habitat & Species Maps for the project area indicate that there are no northern spotted owl nests or Management Circles within 2 miles of the project area in Mabton. Therefore, the proposed improvements to the Mabton WWTF may affect, but are unlikely to adversely affect the northern spotted owl or its critical habitat. Therefore, the proposed project will therefore have no effect on the Northern spotted-owl.

Upper and Middle Columbia River Steelhead (O. mykiss)

According to the WDFW SalmonScape computer application, Middle Columbia chinook inhabit the Columbia River Basin, including the Yakima River near Mabton. Upper Columbia River steelhead could also stray into the Yakima River near the project area (see discussion regarding spring run chinook salmon above). Since the project area is adjacent to the Yakima River these listed salmonids may occur in waters near the project. The WWTF Improvement Project scope does not include work below the Ordinary High Water Mark or within 200 feet of the rivers edge, so construction impacts to listed salmonids are unlikely. The proposed WWTF upgrades will remove ammonia and address existing deficiencies at the WWTF noted earlier.


The WWTF will continue to discharge treated effluent to the Yakima River that meets the requirements of the NPDES permit. Department of Ecology (WAC 173-201A-602) lists the Yakima River as suitable for spawning and rearing of salmonids and other aquatic life. Water quality criteria for the Yakima River have been determined at the Mabton outfall based on the aquatic life use of the Yakima River. Outfall modeling was completed as part of the WWTF Facilities Planning process. The outfall modeling determined that ammonia permit limits for the WWTF must be lowered to meet the Yakima River water quality criteria. The WWTF improvements will enable the WWTF to meet more stringent ammonia limits. In addition, the WWTF improvements will enable the WWTF to meet current NPDES discharge limits, reliably meet oxygen limits, and will remove nitrogen as the population grows through the planning period (2031). The process selected for the WWTF can be upgraded in the future for phosphorus removal which also may be limited in future permits. The outfall modeling (see Facilities Plan, dated June 2011, has shown that the discharge currently meets the water quality criteria for the Yakima River, and that implementing the proposed improvements will allow the facility to meet existing and anticipated permit limits for the next 20 years as the population grows and flows increase. New developments in Mabton will be required to comply with design standards presented in the 2005 Stormwater Manual for Eastern Washington. Improvement of WWTF effluent quality and implementation of the 2005 Stormwater Design Manual will improve water quality and salmonid habitat in the Yakima River near Mabton and downstream. Therefore, the proposed WWTF Improvement Project may affect, but is unlikely to adversely affect the Middle and Upper Columbia River steelhead ESUs. Bull trout (Salvelinus confluentus) – Columbia River distinct population

segment: The WDFW SalmonScape Application indicates that the reach of the Yakima River near the Mabton WWTF outfall provides foraging, rearing and transportation habitat for the Columbia River Bull Trout DPS. The proposed project scope does not include work below the Ordinary High Water Mark or within 200 feet of the rivers edge. Therefore, construction impacts to Columbia River bull trout are unlikely. Outfall modeling was completed as part of the WWTF Facilities Plan. The outfall modeling determined that ammonia permit limits for the WWTF must be lowered to meet the Yakima River water quality criteria. The WWTF improvements will enable the WWTF to meet more stringent ammonia limits. In addition, the WWTF improvements will enable the WWTF to meet current NPDES discharge limits, reliably meet oxygen limits, remove chlorine from the effluent, and will remove nitrogen which might be limited in future permits. The process selected for the WWTF can be upgraded in the future for phosphorus removal which also might be limited in future permits.


Operation of the upgraded WWTF will improve water quality and fish habitat in the Yakima River over the course of the next 20 years. Therefore, the proposed improvements to the Mabton WWTF may affect, but are unlikely to adversely

affect Columbia River bull trout.

Candidate Species

• Pacific fisher (Martes pennanti) West Coast DPS Fishers once inhabited densely forested areas in the lower 48 states including Washington prior to 1940. Trapping has nearly eliminated this species. They generally inhabit heavily forested areas where they prey upon porcupines. Fishers were once present in the Cascade Range and Olympic Mountains, but whether they are present there today is uncertain (Mathews 1999). It is unlikely that fishers would be present in the agricultural lands surrounding the Mabton WWTF; therefore the proposed WWTF Improvement Project will not jeopardize

the continued existence of the Pacific fisher.

• Greater sage grouse (Centrocercus urophasianus) – Columbia Basin DPS The Columbia Basin greater sage grouse is dependent upon sage brush habitat for food and shelter and likely are present in sage dominated areas of Yakima County. Sage grouse are unlikely to be present in the vicinity of the Mabton WWTF, due to the removal of sagebrush from the surrounding area for agricultural development. Construction and operation of the proposed improvements to the Mabton WWTF will improve water quality and potentially adjacent riparian habitat, which may benefit the sage grouse. Therefore, the proposed Mabton WWTF Improvement Project will not jeopardize the

continued existence of the greater sage grouse.

• Mardon skipper (Polites mardon) According to the WDFW Species of Concern Webpage, Mardon Skipper Status Report (7-22-2001), the Mardon skipper is a small, tawny-orange butterfly found only at four small geographically disjunct areas in Washington, Oregon and California. Grasslands in the Puget Sound prairies and Washington’s southern Cascades are believed to support only a few hundred individuals. They are generally found in open, fescue grasslands within Ponderosa pine savanna/woodland at elevations ranging from 1,900 to 5,100 feet in the southern Cascade Range. Elevation of the Yakima River near the Mabton WWTF is approximately 1,000 feet, well below prime habitat for the Mardon skipper. There are no open, fescue grasslands near the WWTF, as all surrounding land is in active agricultural cultivation. Therefore, the proposed Mabton WWTF Improvement Project will not jeopardize the continued existence of the Mardon skipper.

• North American wolverine (Gulo gulo luteus) – contiguous U.S. DPS According to the 12-Month Finding on a Petition to List the North American wolverine as Endangered or Threatened (50 CFR Part 17), the wolverine’s


current range includes Washington state. Wolverines dens are excavated in snow and persistent, stable snow greater than five feet in depth appears to be a requirement for natal denning. In Idaho, natal den sites occur above 8,200 feet in elevation, well above the 1,000 foot elevation at the Mabton WWTF site where snow deep enough for denning is seldom present. Therefore, it is unlikely that the North American wolverine would be present in the project area and the proposed improvements to the Mabton WWTF will not jeopardize the

continued existence of this species.

• Yellow-billed cuckoo (Coccyzus americanus) On July 25, 2001 the US Fish & Wildlife Service issued a one-year petition finding that the western yellow-billed cuckoo warranted listing as threatened throughout its range, but that this listing is precluded by other higher priority actions. According to the WDFW Priority Species and Habitats Website (visited 1-16-03), the range of the western yellow-billed cuckoo includes WDFW Habitat Regions 1, 2 and 4, which correspond to Eastern Washington, North Central Washington and the North Puget Sound regions. While it is possible that the yellow-billed cuckoo could be present in the riparian zone along the Yakima River, it is unlikely that it would be present approximately one quarter mile to the south near the WWTF due to the level of development, human activity and the lack of suitable habitat, as the surrounding area is farmland. Therefore, the proposed Mabton WWTF Improvement Project will not jeopardize the

continued existence of the yellow-billed cuckoo.

Essential Fish Habitat Construction of proposed improvements to the Mabton WWTF will occur approximately one-half mile from the Yakima River and are unlikely to impact EFH for commercially important chinook and coho salmon. Operation of the proposed improvements to the Mabton WWTF will improve water quality and fish habitat in the Yakima River through the planning period (2031). Therefore, the proposed project will have no effect on EFH in the Yakima River.

3. Conservation Measures

• Construction BMPs for the control of sedimentation and erosion shall be implemented during construction to minimize the potential for turbid runoff leaving the site.


4. Conclusions Provided Construction BMPs for the control of sedimentation and erosion are implemented during construction, proposed improvements to the Mabton WWTF site and adjacent agricultural lands will have no effect on the following species:

• Marbled murrelet • Northern spotted owl • Grizzly bear • Gray wolf

Proposed improvements to the Mabton WWTF will remove chlorine and ammonia from the effluent discharged to the Yakima River and improve habitat for listed salmonids present. Therefore, the proposed Mabton WWTF Improvement Project may affect, but is unlikely to adversely affect the following salmonid species present in the Yakima River:

• Columbia River bull trout • Upper Columbia chinook salmon • Middle Columbia River steelhead • Upper Columbia River steelhead

Essential Fish Habitat Construction and operation of the propose improvements to the Mabton WWTF will have no effect on EFH for commercially important Columbia River chinook or coho salmon present in the Yakima River.


5. References

Federal Register Vol. 75, No. 239 2010. 50 CFR Part 17 Endangered and Threatened

Wildlife and Plants; 12-Month Finding on a Petition to List the North American Wolverine as Endangered or Threatened, December 14.

Federal Register Vol. 66, No. 88 2001. 50 CFR Part 17 Endangered and Threatened

Wildlife and Plants; 12-Month Finding for a Petition to List the Washington Population of the Western Sage Grouse (Centrocercus urophasianus phaios).

Gray & Osborne, Inc. 2004. Biological Evaluation for Klickitat Community Wastewater

Treatment Plant Upgrade and Collection System Improvements, prepared for consultation with the US Fish & Wildlife Service and the National Marine Fisheries Service for Klickitat PUD #1, Seattle Office, February 25.

Gray & Osborne, Inc. 2004. Biological Assessment: Wastewater Treatment Facility

Project, prepared for consultation with the US Fish & Wildlife Service and National Marine Fisheries Service, Seattle Office, August.

Hart, J.L. 1973. Pacific Fishes of Canada, Fisheries Research Board of Canada,

Bulletin 180, Ottawa, Canada. Hogarth, William T., Ph.D., 2001. National Finding for use of Endangered Species Act,

Section 7 Consultation Process to Complete Essential Fish Habitat Consultations, National Marine Fisheries Service, February 28.

King County Department of Natural Resources 2000. Literature Review and

Recommended Sampling Protocol for Bull Trout in King County, R2 Resource Consultants, Seattle, Washington, May.

Mathew’s, Daniel 1999. Cascade-Olympic Natural History, A Trailside Reference,

Second Edition, Raven Editions, Portland Oregon. National Marine Fisheries Service, 2004. Northwest Region Listed Species Webpage.

July 1. U.S. Fish & Wildlife Service 2010. Listed and Proposed Endangered and Threatened

Species and Critical Habitat: Candidate Species; and Species of Concern in Yakima County, Washington, Olympia Office, prepared by the USFWS Central Washington Field Office, December 15.

Washington State Department of Ecology 2000, 2000 Washington State Water Quality

Assessment, Section 305 (b) Report, Olympia, Washington, August. Washington State Department of Fish and Wildlife 2011. Salmonscape Application,

website visited May 11.


Washington State Department of Fish and Wildlife 2011. Priority Species and Habitats

Maps for the vicinity of T09,R23E, Section 31, prepared by the Priority Species and Habitats Group, Olympia, Washington, February 8.

Washington State Department of Fish and Wildlife 1994. Salmon and Puget Sound

chinook salmon Stock Inventory, Appendix 1, Puget Sound Stocks, Olympia, Washington, June.

Washington State Department of Fish and Wildlife 1999. Mardon Skipper Status

Report: Executive Summary, website visited July 23, 2001. Washington State Department of Fish and Wildlife 1998. Salmonid Stock Inventory:

Appendix: Bull Trout and Dolly Varden, Olympia, Washington, July. Williams & Williams 1975. A Catalog of Washington Streams and Salmon Utilization,

Volume 1, Puget Sound Region, Washington Department of Fisheries. Washington Department of Fish and Wildlife 2003. Priority Species List Web Site

(Yellow-billed cuckoo), visited January 16.


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WAC 197-11-970 Determination of Nonsignificance (DNS).

Description of proposal:

Wastewater Facility Plan. The Wastewater Facility Plan is a planning tool to be used by the City of Mabton in conjunction with the City’s current Comprehensive Plan under the Growth management Act (GMA). The Wastewater Facility Plan

describes the type of facilities needed to provide wastewater treatment service to the planning area to meet present and future needs. The proposal provides a method of implementing the various proposed projects based on need and the effect financing may have on sewer rates. The Wastewater Facility Plan determined that the wastewater facility needs to be expanded to serve the sewer needs for the next twenty years.

Proponent: City of Mabton

Location of proposal, including street address, if any:

The Wastewater Facility Plan encompasses the entire UGA boundary. The improvements will be at the Wastewater Treatment Facility along Vance Road.

Lead agency: City of Mabton

The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21C.030 (2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request.

There is no comment period for this DNS.

This DNS is issued after using the optional DNS process in WAC 197-11-355. There is no further comment period on the DNS.

This DNS is issued under WAC 197-11-340(2); the lead agency will not act on this proposal for 14 days from the date below. Comments must be submitted by _______.

Responsible official: Angel Reyna

Position/title: Mayor Phone: (509) 849-4096

Address: P.O Box 655, Mabton WA 98935

Date: ______

Signature:

WAC 197-11-960 Environmental checklist.

ENVIRONMENTAL CHECKLIST Purpose of checklist: The State Environmental Policy Act (SEPA), chapter 43.21C RCW, requires all governmental agencies to consider the environmental impacts of a proposal before making decisions. An environmental impact statement (EIS) must be prepared for all proposals with probable significant adverse impacts on the quality of the environment. The purpose of this checklist is to provide information to help you and the agency identify impacts from your proposal (and to reduce or avoid impacts from the proposal, if it can be done) and to help the agency decide whether an EIS is required. Instructions for applicants: This environmental checklist asks you to describe some basic information about your proposal. Governmental agencies use this checklist to determine whether the environmental impacts of your proposal are significant, requiring preparation of an EIS. Answer the questions briefly, with the most precise information known, or give the best description you can. You must answer each question accurately and carefully, to the best of your knowledge. In most cases, you should be able to answer the questions from your own observations or project plans without the need to hire experts. If you really do not know the answer, or if a question does not apply to your proposal, write "do not know" or "does not apply." Complete answers to the questions now may avoid unnecessary delays later. Some questions ask about governmental regulations, such as zoning, shoreline, and landmark designations. Answer these questions if you can. If you have problems, the governmental agencies can assist you. The checklist questions apply to all parts of your proposal, even if you plan to do them over a period of time or on different parcels of land. Attach any additional information that will help describe your proposal or its environmental effects. The agency to which you submit this checklist may ask you to explain your answers or provide additional information reasonably related to determining if there may be significant adverse impact. Use of checklist for nonproject proposals: Complete this checklist for nonproject proposals, even though questions may be answered "does not apply." IN ADDITION, complete the SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (part D). For nonproject actions, the references in the checklist to the words "project," "applicant," and "property or site" should be read as "proposal," "proposer," and "affected geographic area," respectively. A. BACKGROUND 1. Name of proposed project, if applicable:

Waste Water Treatment Facility (WWTF) Improvement Plan 2. Name of applicant:

City of Mabton 3. Address and phone number of applicant and contact person:

Ret Stewart City Clerk P.O. Box 655 Mabton, WA, 98935 (509) 849-4096

4. Date checklist prepared:

March 22, 2011

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5. Agency requesting checklist:

City of Mabton 6. Proposed timing or schedule (including phasing, if applicable):

Construction of Improvements to the wastewater treatment facility with the following schedule:

• Design of wastewater treatment facility 2012 • Construction of wastewater treatment facility 2013-2014

Schedule is dependent on funding and the schedule will be postponed if funding sources are not available.

7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain.

No, the improvements to the wastewater treatment facility are design for twenty years until 2031.

8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal.

In addition to the SEPA, a NEPA Environmental report will be prepared for the WWTF Plan. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain.

There are no known applications pending governmental approval directly affecting this project. 10. List any government approvals or permits that will be needed for your proposal, if known.

1. Department of Ecology Plan Approval 2. Department of Ecology Design Approval 3. Building Permit for the construction 4. Annexation of the WWTF into the City limits 5. Vacation of a Right-of-Way to the west of the WWTF by the City of Mabton

11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. (Lead agencies may modify this form to include additional specific information on project description.)

The City is planning on construction one of two alternatives; either a sludge drying bed alterative or a mechanical dewatering alternative. The sludge drying bed alterative will require land purchase while the other alternative will not. If the City can purchase the land, the City will construct the sludge drying bed alternative. Both alternatives are basically similar and both are described below. The WWTF improvements will consist of the following at the existing site of the WWTF: • Construction of headworks • Construction of new aerobic basin with anoxic basin and bioselectors • Construction of a new secondary clarifier with retaining wall along Vance Road • Replacement of ultraviolet disinfection system inside of existing building • Replacement of effluent pumps inside of existing structure • Construction of a new effluent aeration manhole

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• Construction of new sludge drying beds or construction of mechanical dewatering building • Modifications to existing secondary clarifier, aerobic sludge holding tank and laboratory building • Piping and electrical improvements

See attached figures for both alternatives.

12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applications related to this checklist.

The proposed project site is located in Yakima County, Washington T9N, R23E, S31, north of the town of Mabton. The Waste Water Treatment Facility is situated approximately one mile north of the City center along Vance Road. (See vicinity and topo maps).

B. ENVIRONMENTAL ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, hilly, steep slopes, mountainous,

other . . . . . . b. What is the steepest slope on the site (approximate percent slope)?

The site generally slopes 0.5 percent. The steepest slope on the existing site is approximately 50 percent along Vance road. A retaining wall will be constructed in this area for the installation of a secondary clarifier.

c. What general types of soils are found on the site (for example, clay, sand, gravel, peat,

muck)? If you know the classification of agricultural soils, specify them and note any prime farmland.

According to the NRCS Soil Survey map for the area, the site is composed entirely of silt loams including Warden silt loam, Umapine silt loam, and Esquatzel silt loam. Slopes are generally in the range of 0 to 2 percent. See attached soils map.

d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe.

There is no history of unstable soils in the vicinity.

e. Describe the purpose, type, and approximate quantities of any filling or grading proposed. Indicate Source of fill.

Soil will be excavated for the construction of the structures with the following quanities: • Excavation approximately 3,500 cubic yards • Wall backfill with native soils approximately 1,200 cubic yards • Waste haul offsite approximately 2,300 cubic yards.

f. Could erosion occur as a result of clearing, construction, or use? If so, generally describe.

No. Construction work would include practices to prevent the possible minor erosion problems that may occur at that time.

` g. About what percent of the site will be covered with impervious surfaces after project

construction (for example, asphalt or buildings)?

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The existing site is approximately 100 percent covered in impervious area. The new site will be approximately 90 to 100 percent impervious.

h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any:

Construction Contract Documents will require erosion control features which will follow the Washington State Department of Ecology’s Stormwater Management Manual for Eastern Washington.

2. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile, odors, industrial wood

smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known.

Exhaust emissions from construction equipment will occur during construction. Dust may be emitted during excavation and backfill operations. No new odor sources will be added to the WWTF.

b. Are there any off-site sources of emissions or odor that may affect your proposal? If so, generally describe.

There are no off-site sources of emissions of odor that may affect the project.

c. Proposed measures to reduce or control emissions or other impacts to air, if any:

The Contract Documents contain provisions for dust control during construction, to include moistening of exposed soil. The Contractor will be required to be in compliance with WAC 173-400-040, which notes that fugitive dust from the construction site shall be controlled. In addition, dust and exhaust from the project site shall not become a nuisance to neighboring residents. These measures will be enforced during construction. The Contractor will also be required to keep construction equipment in proper working order to minimize exhaust emissions during construction.

3. Water a. Surface:

1) Is there any surface water body on or in the immediate vicinity of the site (including year round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into.

The Yakima River flow one-quarter mile to the northwest of the proposed project area. The Yakima River flows into the Columbia River.

2) Will the project require any work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans.

The project will not require work over, in, or within 200 feet from the described waters..

3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. Does not apply.

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4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quantities if known.

The proposal will not require surface water withdrawals or diversions.

5) Does the proposal lie within a 100-year floodplain? If so, note location on the site plan.

According to the FEMA Flood Insurance Rate Map, the proposed project area does not lie within the 100 year flood plain. See attached FIRM Map.

6) Does the proposal involve any discharges of waste materials to surface waters? If so,

describe the type of waste and anticipated volume of discharge.

The existing WWTF, discharges to the Yakima River with NPDES permit WA-002064-8 and the upgraded WWTF will continue to discharge to the Yakima River. The existing permit expiration date is April 30, 2012.

b. Ground:

1) Will ground water be withdrawn, or will water be discharged to ground water? Give general description, purpose, and approximate quantities if known.

During construction deeper excavations will require ground water pumping to allow excavations to occur in the dry. No long term ground water withdrawal will occur.

2) Describe waste material that will be discharged into the ground from septic tanks or other sources, if any (for example: Domestic sewage; industrial, containing the following chemicals. . . ; agricultural; etc.). Describe the general size of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(s) are expected to serve.

There will be no material discharged into the ground as a result of this project.

c. Water runoff (including stormwater):

1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe.

The existing WWTF runoff flows to drywells or trench drains for infiltration. Water flowing onto new tanks or structures will be included and treated with the wastewater. Most new impervious area will be structures or tanks and thus stormwater will be treated with the wastewater. Any new impervious area will be collected and treated with drywells or trench drains for infiltration as is currently practiced.

2) Could waste materials enter ground or surface waters? If so, generally describe.

Storm water runoff will enter groundwater thru drywells and or trench drains.

d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any:

Best management practices as required by Washington State Department of Ecology’s Stormwater Management Manual for Eastern Washington.

4. Plants

6

a. Check or circle types of vegetation found on the site: deciduous tree: alder, maple, aspen, other evergreen tree: fir, cedar, pine, other shrubs X pasture

grass

X wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other

crop or grain

water plants: water lily, eelgrass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered?

Approximately 1.5 to 2.0 acres of crop land will be removed or altered c. List threatened or endangered species known to be on or near the site.

According to the Washington Department of Fish and Wildlife Priority Habitat and Species maps, there are no known threatened or endangered plant species on or near the project site. See attched PHS Map.

d. Proposed landscaping, use of native plants, or other measures to preserve or enhance

vegetation on the site, if any:

All disturbed areas not part of the gravel, asphalt, or concrete surface will be receive hydroseeding or grass sod for erosion control.

5. Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: fish: bass, salmon, trout, herring, shell fish, other:

birds: hawk, heron, eagle, songbirds, other: mammals: deer, bear, elk, beaver, other: coyote, small mammals such as mice b. List any threatened or endangered species known to be on or near the site.

There are no known threatened or endangered species on or near the project site. However the Yakima River is ¼ mile away and it has endangered species of salmon and bull trout. See attached PHS Map.

c. Is the site part of a migration route? If so, explain.

The Yakima River which is ¼ mile away is utilized for migration of fish species. d. Proposed measures to preserve or enhance wildlife, if any:

Not applicable. 6. Energy and natural resources

7

a. What kinds of energy (electric, natural gas, oil, wood stove, solar) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc.

Approximately 70 horsepower of additional electrical energy will be utilized and the WWTF.

b. Would your project affect the potential use of solar energy by adjacent properties?

If so, generally describe.

No, the tallest new structure might be ten feet high. c. What kinds of energy conservation features are included in the plans of this proposal?

List other proposed measures to reduce or control energy impacts, if any:

Energy efficient pumps and motors will be selected. The new aeration basin and existing oxidation ditch will have variable frequency drives, oxygen sensors and a control algorithm to minimize the use of electrical power in the blowers.

7. Environmental health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk

of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe.

There are no environmental health hazards that could occur as a result of this project.

1) Describe special emergency services that might be required. No special emergency services will be required. 2) Proposed measures to reduce or control environmental health hazards, if any: No chemicals are required for the operation of the WWTF. The only hazardous materials associated with the proposed project would be fuels, lubricants, and coolants used in construction equipment. The Contractor will be required to generate a Spill Prevention, Control, and Countermeasures Plan (SPCC) prior to starting construction to address potential health hazards during the course of construction. In addition, construction equipment will be fitted with spill containment/response kits and crews will be trained in their use.

b. Noise

1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)?

No foreseeable noises exist in the area that would affect the project.

2) What types and levels of noise would be created by or associated with the project on a

short-term or a long-term basis (for example: traffic, construction, operation, other)? Indi- cate what hours noise would come from the site.

8

New blowers will be enclosed in sound attenuating outdoor enclosures. The WWTF will have two new 15 horsepower blowers. There would be short-term heavy equipment use during construction. Construction activities would be limited to normal daytime working hours. No noise would be created on a long-term basis.

3) Proposed measures to reduce or control noise impacts, if any:

The blowers will be enclosed in sound attenuating outdoor enclosures. Construction work would occur during daylight hours only.

8. Land and shoreline use a. What is the current use of the site and adjacent properties?

The current use of the project site is a municipal waste water treatment facility. To the north and west of the WWTF is farmland. To the south and east of the WWTF is a cemetery.

b. Has the site been used for agriculture? If so, describe.

Yes. Approximately 1.5 to 2 acres of farmland will be converted to a WWTF. c. Describe any structures on the site.

The existing structures on-site include a lab and maintenance building, storage tanks, pump station, clarifiers, oxidation ditch, sludge conditioning tank, and sludge drying beds.

d. Will any structures be demolished? If so, what?

Several in ground tanks and structures will be demolished (less than 10’x10’ in size). e. What is the current zoning classification of the site?

The existing WWTF is zoned Residential 1 and the adjacent farmland to the west is zoned industrial and to the north is zoned agricultural

f. What is the current comprehensive plan designation of the site?

The designation is Urban (Urban Growth Area). g. If applicable, what is the current shoreline master program designation of the site?

Not applicable. h. Has any part of the site been classified as an "environmentally sensitive" area? If so, specify.

No. i. Approximately how many people would reside or work in the completed project?

Two people will work at the site. j. Approximately how many people would the completed project displace?

9

No one will be displaced by this project.

k. Proposed measures to avoid or reduce displacement impacts, if any:

Not applicable. l. Proposed measures to ensure the proposal is compatible with existing and projected land

uses and plans, if any:

Approximately 1.5 to 2 acres farmland will be converted to WWTF which is compatible with the existing WWTF.

9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, mid-

dle, or low-income housing.

No housing units will be provided. b. Approximately how many units, if any, would be eliminated? Indicate whether high,

middle, or low-income housing.

No housing units will be eliminated. c. Proposed measures to reduce or control housing impacts, if any:

There will be no impacts to housing associated with this project, therefore no measures are proposed. 10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is

the principal exterior building material(s) proposed?

The tallest new structure might be ten feet high. b. What views in the immediate vicinity would be altered or obstructed?

No views in the immediate vicinity would be altered or obstructed as a result of this project. c. Proposed measures to reduce or control aesthetic impacts, if any:

There will be no impacts to aesthetics associated with this project, therefore no measures are proposed. 11. Light and glare a. What type of light or glare will the proposal produce? What time of day would it mainly

occur? None.

b. Could light or glare from the finished project be a safety hazard or interfere with views?

No. c. What existing off-site sources of light or glare may affect your proposal?

10

No existing off-site sources of light or glare will affect this proposal.

d. Proposed measures to reduce or control light and glare impacts, if any:

There will be no impacts to light and glare associated with this project, therefore no measures are proposed.

12. Recreation a. What designated and informal recreational opportunities are in the immediate vicinity?

None b. Would the proposed project displace any existing recreational uses? If so, describe.

The proposed project would not displace any existing recreational uses. c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by

the project or applicant, if any:

There will be no impacts to recreation and recreation opportunities associated with this project, therefore no measures are proposed.

13. Historic and cultural preservation a. Are there any places or objects listed on, or proposed for, national, state, or local preser-

vation registers known to be on or next to the site? If so, generally describe.

No. b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or

cultural importance known to be on or next to the site.

Not Applicable.

c. Proposed measures to reduce or control impacts, if any:

A request for a Historic and Cultural Resources Review of the project site was submitted to the Washington State Department of Archaeology and Historic Preservation. A response was received concurring in the determination that no historic or archaeological properties would be affected by this project. An Unanticipated Discovery Plan will be generated prior to start of construction that will help with the proper treatment of cultural resources and human remains in the event of the inadvertent disturbance of such during construction. It will also provide guidelines for the proper procedures and contacts to make in the event that materials are disturbed.

14. Transportation a. Identify public streets and highways serving the site, and describe proposed access to the

existing street system. Show on site plans, if any. The streets serving the project site is Vance Road (See attached maps).

11

There will be no modifications to existing street access as a result of this project. A site map is attached.

b. Is site currently served by public transit? If not, what is the approximate distance to the nearest transit stop?

No. Approximately 1 mile.

c. How many parking spaces would the completed project have? How many would the

project eliminate?

No additional parking spaces will be required. No parking spaces will be eliminated. d. Will the proposal require any new roads or streets, or improvements to existing roads or

streets, not including driveways? If so, generally describe (indicate whether public or private).

No new roads or streets will be created. No improvements to existing roadways will be required.

e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transporta-

tion? If so, generally describe.

The project will be in the vicinity of the Pacific Northern railroad approximately 1 mile to the south. f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak

volumes would occur.

No additional vehicular trips would be generated. g. Proposed measures to reduce or control transportation impacts, if any:

Not applicable. 15. Public services a. Would the project result in an increased need for public services (for example: fire pro-

tection, police protection, health care, schools, other)? If so, generally describe.

No. b. Proposed measures to reduce or control direct impacts on public services, if any.

There will be no impact to public services as a result of the project. 16. Utilities

a. Circle utilities currently available at the site: electricity, natural gas, water, refuse service, telephone, sanitary sewer, septic system, other.

b. Describe the utilities that are proposed for the project, the utility providing the service,

and the general construction activities on the site or in the immediate vicinity which might be needed.

Electricity will be provided by the Pacific Power, telephone by Qwest, water and sanitary sewer by the City of Mabton.

12

C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: ................................................................................................................................................................................ Date Submitted: ......................................................................................................................................................................

13

D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent of the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity of at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water; emissions to air; production, storage, or release of

toxic or hazardous substances; or production of noise? The WWTF currently serves a population of 2,165 people the WWTF expansion is designed to serve a population of 3,100 people; therefore the discharge treated wastewater to the River will increase.

Proposed measures to avoid or reduce such increases are:

Outfall modeling was completed which shows that the discharge will meet water quality standards. The expanded WWTF will include nitrogen removal and will treat ammonia to higher level than the existing WWTF.

2. How would the proposal be likely to affect plants, animals, fish, or marine life? The discharge to the Yakima River will increase because of population growth.

Proposed measures to protect or conserve plants, animals, fish, or marine life are: The WWTF will continue to discharge treated effluent to the Yakima River that meets the requirements of the NPDES permit. Department of Ecology (WAC 173-201A-602) list the Yakima River for spawning and rearing of aquatic life. Based on the aquatic life use of the Yakima River water quality criteria for the Yakima River is determined for the Yakima River at the Mabton outfall. Outfall modeling was completed as part of the WWTF Plan. The outfall modeling determined that ammonia permit limits for the WWTF must be lowered to meet the Yakima River water quality criteria. The WWTF improvements will enable the WWTF to meet more stringent ammonia limits. In addition, the WWTF improvements will enable the WWTF to meet current NPDES discharge limits, reliably meet oxygen limits, and will remove nitrogen which might be limited in future permits. The process selected for the WWTF can be upgraded in the future for phosphorus removal which also might be limited in future permits. The outfall modeling has shown that the discharge meets the water quality criteria for the Yakima River. The water quality criteria for the Yakima River protects aquatic life therefore the effluent discharged will also not affect aquatic life including endangered species in the Yakima River.

3. How would the proposal be likely to deplete energy or natural resources? The WWTF expansion will use approximately 70 more horsepower of electricity.

Proposed measures to protect or conserve energy and natural resources are: Energy efficient pumps and motors will be selected. The new aeration basin and existing oxidation ditch will have variable frequency drives, oxygen sensors and a control algorithm to minimize the use of electrical power in the blowers.

14

4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection: such as parks, wilderness, wild and scenic rivers, threatened or endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? Will not affect sensitive areas.

Proposed measures to protect such resources or to avoid or reduce impacts are:

Not applicable.

5. How would the proposal be likely to affect land and shoreline use, including whether it would allow or encourage land or shoreline uses incompatible with existing plans?

Will not affect shoreline areas.

Proposed measures to avoid or reduce shoreline and land use impacts are: Not applicable. 6. How would the proposal be likely to increase demands on transportation or public services and utilities?

Will not increase demand on transportation or public service. The WWTF expansion will use approximately 70 more horsepower of electricity.

Proposed measures to reduce or respond to such demand(s) are:

Energy efficient pumps and motors will be selected. The new aeration basin and existing oxidation ditch will have variable frequency drives, oxygen sensors and a control algorithm to minimize the use of electrical power in the blowers.

7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection

of the environment.

Will not conflict with local, state or federal laws.


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Soil Map—Yakima County Area, Washington

Natural ResourcesNatural ResourcesNatural ResourcesNatural ResourcesConservation ServiceConservation ServiceConservation ServiceConservation Service


12/28/2010Page 1 of 3

MAP LEGEND MAP INFORMATION

Area of Interest (AOI)Area of Interest (AOI)

SoilsSoil Map Units

Special Point FeaturesBlowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line FeaturesGully

Short Steep Slope

Other

Political FeaturesCities

Water FeaturesOceans

Streams and Canals

TransportationRails

Interstate Highways

US Routes

Major Roads

Local Roads

Map Scale: 1:2,460 if printed on A size (8.5" × 11") sheet.

The soil surveys that comprise your AOI were mapped at 1:24,000.

Please rely on the bar scale on each map sheet for accurate mapmeasurements.

Source of Map: Natural Resources Conservation ServiceWeb Soil Survey URL: http://websoilsurvey.nrcs.usda.govCoordinate System: UTM Zone 11N NAD83

This product is generated from the USDA-NRCS certified data as ofthe version date(s) listed below.

Soil Survey Area: Yakima County Area, WashingtonSurvey Area Data: Version 10, Jun 12, 2009

Date(s) aerial images were photographed: 7/1/2006

The orthophoto or other base map on which the soil lines werecompiled and digitized probably differs from the backgroundimagery displayed on these maps. As a result, some minor shiftingof map unit boundaries may be evident.




12/28/2010Page 2 of 3

Map Unit Legend

Yakima County Area, Washington (WA677)

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

32 Esquatzel silt loam, 0 to 2 percent slopes 4.3 18.7%

58 Hezel loamy fine sand, 2 to 15 percentslopes

1.7 7.2%

169 Umapine silt loam, drained, 0 to 2 percentslopes

6.4 27.9%

172 Warden fine sandy loam, 0 to 2 percentslopes

0.8 3.3%

177 Warden silt loam, 2 to 5 percent slopes 9.8 42.9%

Totals for Area of Interest 22.9 100.0%




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Species1


Listing Status2




















































APPENDIX F

MABTON GREEN PROJECTS WATER & ENERGY EFFICIENCY ALTERNATIVES

STUDY

MABTON GREEN PROJECTS Water & Energy Efficiency Alternatives Study

CCCiiitttyyy ooofff MMMaaabbbtttooonnn,,, WWWaaassshhhiiinnngggtttooonnn

Prepared For:

THE CITY OF MABTON 305 MAIN STREET

MABTON, WA 98935

AUGUST 2011

Prepared By:

Mabton Green Projects Water and Energy Efficiency Alternatives

August 2011

2020 ENGINEERING, Inc. i

Table of Contents

Part 1: Water Efficiency ............................................................................................... 2

1. Assumptions ................................................................................................................. 2

2. Environmental Factors ................................................................................................. 2

a. Climate ........................................................................................................................... 3

b. Soils ............................................................................................................................... 3

c. Ground and Surface Water ............................................................................................. 4

B. Methodology ................................................................................................................. 5

C. Water Conservation ...................................................................................................... 5

1. WW1- LOW FLOW (FIXTURE RETROFIT) .................................................................... 7

D. Water Reuse and Decentralized Wastewater Treatment ...........................................10

2. WW6- LOW FLOW/ LIGHT GREYWATER IRRIGATION ..............................................11

3. WW8- LOW FLOW/GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION ..........13

4. WW10- DECENTRALIZED TREATMENT AND WATER REUSE ..................................15

E. Summary (Part 1: Water Efficiency) ...........................................................................17

Part 2: Energy Efficiency (Natural Wastewater Treatment Alternatives) ............... 20

A. Introduction .................................................................................................................20

B. Natural Treatment Systems (Overview) .....................................................................20

1. Lagoon Options .............................................................................................................20

2. Wetland Options ............................................................................................................22

C. Wastewater Description and Discharge Standards ..................................................24

D. Low Energy Wastewater Treatment Alternatives ..........................................................27

1. Facultative Lagoon and Surface Flow Wetland ..............................................................27

2. Aerated Lagoon and Surface Flow Wetland ..................................................................27

3. Aerated Gravel Bed: Third Stage Polishing/Ammonia Removal .....................................27

4. Zero Discharge and/or Controlled Batch Discharge .......................................................28

5. Nitrogen Removal ..........................................................................................................29

6. Phosphorous Removal ..................................................................................................29

7. Sludge Management .....................................................................................................29

8. Temperature and Dissolved Oxygen .............................................................................30

9. Disinfection ....................................................................................................................30

10. Costs ...........................................................................................................................31

E. Summary (Part 2: Energy Efficiency) .........................................................................32

F. References (Part 2) ......................................................................................................37


August 2011

2020 ENGINEERING, Inc. ii

List of Figures

Figure 1 Site Map. ........................................................................................................................................................ 1

Figure 2. Wastewater Treatment Facility Site. .......................................................................................................... 1

Figure 3. USDA Web Soil Survey Area of Interest Boundary .................................................................................. 4

Figure 4. WW1-Low Flow (Fixture Retrofit) Flow Diagram. ..................................................................................... 7

Figure 5. WW1 Estimated Cost of Ownership............................................................................................................ 9

Figure 6. WW6-Low Flow/Light Greywater Irrigation Diagram. .............................................................................. 11

Figure 7. WW8-Low Flow/Greywater Toilet Flush/ Light Greywater Irrigation Diagram. .................................... 13

Figure 8. WW10 Decentralized Wastewater Treatment Diagram. .......................................................................... 15

Figure 9. ...................................................................................................................................................................... 17

Figure 10. Projected Flow Comparison for Various Sustainable Water Efficiency Strategies. .......................... 19

Figure 11. Typical Facultative Lagoon ..................................................................................................................... 21

Figure 12. Surface Flow Wetland Adjacent to Venice, Italy ................................................................................... 23

Figure 13. Sludge Dewatering Reed Ben, Pine River, Minnesota ......................................................................... 23

Figure 14. City of Mabton 2010 Average Monthly Temperatures .......................................................................... 25

Figure 15. City of Mabton Net Water Gain/Loss by Month ..................................................................................... 26

Figure 16. Alternative A-2 Process Diagram ........................................................................................................... 34

Figure 17. Alternative A-2 Site Plan ......................................................................................................................... 35

Figure 18. Alternative A-2 Process Diagram ............................................................................................................ 36

List of Tables

Table 1. Housing Assumptions .................................................................................................................................. 2

Table 2. Mabton School Population Estimates. ......................................................................................................... 2

Table 3. Monthly Climate Summary ........................................................................................................................... 3

Table 4. Sustainable Water Efficiency Strategy Summary. ..................................................................................... 6

Table 5. WW1- Low Flow (Fixture Retrofit) Estimate ................................................................................................ 7

Table 6. WW1 Cost Estimate ...................................................................................................................................... 8

Table 7. Chapter 246-274 WAC Greywater Reuse for Subsurface Irrigation. ....................................................... 10

Table 8. Flow Estimates Using Light Greywater for Irrigation .............................................................................. 11

Table 9. WW6 Cost Estimate. ................................................................................................................................... 12

Table 10. Using Light Greywater Produced from Low Flow Fixtures for Toilet Flush and Irrigation. ................ 13

Table 11. WW8 Cost Estimate .................................................................................................................................. 14

Table 12. Neighborhood Scale Treatment System Flow Estimate ........................................................................ 15

Table 13. WW10 Cost Estimate ................................................................................................................................ 16

Table 14. Projected Population and Flows for Various Sustainable Water Efficiency Strategies. ..................... 19

Table 15. 2031 City of Mabton Design Criteria........................................................................................................ 24

Table 16. City of Mabton Projected NPDES Permit Effluent Limits (Next Permit Cycle) ..................................... 24

Table 17. Sludge Management- Pump and Land Apply ......................................................................................... 29

Table 18. Low Energy Treatment Alternative Summary ........................................................................................ 31

Table 19. Selected Low Energy Treatment Alternatives ........................................................................................ 33


August 2011

2020 ENGINEERING, Inc. iii

Appendices Appendix A 1. Sustainable Strategy Flow Household Estimates (WW1-WW10) 2. Estimated Cost of Ownership

• WW1

• WW6

• WW8 • WW10

Appendix B 1. Example Low Flow Fixtures

• High efficiency toilets

• Shower heads

• Clothes washing machines

• Dishwashers 2. Greywater Irrigation Systems

• BRAC

• Aqua2Use

• Flotender 3. Decentralized Treatment Systems

• Advantex Treatment System

• Aquacell Membrane Bioreactor

• Living Machine™

• Netafim

Appendix C 1. Decentralized Wastewater and Water Reuse Examples

• San Juan Community Home Trust

• YMCA Camp Seymour

• Islandwood

• Bertschi School (LBC)

• Cascadia Center for Sustainable Design and Construction 2. Constructed Wetland Engineering (consultants, including project examples)

• Aqua Nova Consulting

• Naturally Wallace Consulting

• Nova Tec Engineering

Appendix D 1. Chapter 246-274 WAC: Greywater Reuse for Subsurface Irrigation (Effective July 31, 2011) 2. Chapter 51-56 and 51-57 WAC: Universal Plumbing Code and Universal Plumbing Code Standards 3. EPA: Case Studies in Water Conservation 4. Living Building Challenge 5. Yakima Valley Conference of Governments: City of Mabton Information

• FEMA Flood Plain Designation

• Critical Aquifer Recharge Area 6. City of Mabton 2009 Comprehensive Plan: Natural Systems Element

• Wetlands and Water Bodies 7. City of Mabton 6 Year Budget 8. Water Right Self Assessment Form 9. City of Mabton WWTF Facility Plan - WWTF Aeration Alternative No. 3


August 2011

2020 ENGINEERING, Inc. 1

Figure 1 Site Map. City of Mabton (limits outlined in orange) and the wastewater treatment facility location (outlined in red). An enlarged image of the wastewater treatment facility is also shown below.

.

Legend: City Limits Wastewater Treatment Plant Location

Figure 2. Wastewater Treatment Facility Site. An enlarged image of the

wastewater treatment facility is also shown below


August 2011


Year Population

Single Family

Housing Units

Multifamily

Units

Manufactured Homes &

Other Housing Total

2008 2,085 337 83 98 518

2010 2,165 345 85 100 531

Housing Type

Elementary School 514

Middle School 159

High School 264

Teachers and Other Faculty 171

Total 1108

2010 Mabton School Population

Part 1: Water Efficiency

A. Introduction

Water conservation is an integral part to preserving and prolonging our precious natural resources as well as our ecosystem as a whole. Water is life. The Clean Water Act has gone a long way in bringing attention to water quality and quantity issues in our country and around the world in the past 40 years. Many municipalities, water and wastewater purveyors, environmentalists, economists, engineers, and green building standards have recognized the energy, environmental, and economic benefits of water conservation. In many ways initiatives from conservationists and the green building industry (i.e., BuiltGreen, LEED and Living Building Challenge) have set high goals for water and wastewater purveyors to look more closely at how they use, reuse and/or treat the water before releasing it back to the environment. Some of these goals have now become standards, and are recognized as minimum efficiencies as demonstrated by the reduction in maximum flush volumes for toilet fixtures nearly 20 years ago. Great strides have been made, and must continue to be made in order to help sustain our environment. Some of the leading cities who have recognized the benefits of water conservation and its effects on energy, the environment, and the economy include Ashland, Oregon; Goleta, California; Houston, Texas; New York City, New York; Santa Monica, California; Tampa, Florida; and Barrie, Ontario (See Appendix D for EPA report). A number of Pacific Northwest cities, such as Lacey, Olympia and Tacoma, have emphasized the importance of water conservation through fixture rebates and other incentive programs. All of these cities implemented plumbing fixture retrofits. The Seattle Saving Water Partnership has also offered toilet rebates for new construction. Each city has experienced substantial water demand reductions, and in turn wastewater flow reductions. These reductions reduce the operations and maintenance efforts, energy demands, aquifer depletion, and stress on existing infrastructure. With our ever growing population, together with industry that demand water resources, cost-effective conservation efforts are paramount in order to help sustain our communities.

1. Assumptions

The City of Mabton (City) is located in Yakima County, Washington, United States, bordering the eastern edge of the Yakama Indian Reservation. Figure 1 provides an area map with City boundaries (orange outline); Figure 2 specifies the wastewater treatment plan location. The City population in 2010 was 2,165. We have determined that the Cities major dischargers of wastewater are the approximately 531 housing units, projected from the City of Mabton Comprehensive Plan (2009), and 3 schools. Summary table of each contributor are shown below. Table 1. Housing Assumptions. Estimates the total 2010 housing units based on the 2008 ratio of various

housing units to population.

Table 2. Mabton School Population Estimates.


August 2011


2. Environmental Factors

Various natural features of the service area are discussed below, such as climate, geology, soils, flood plains, and surface and groundwater resources.

a. Climate

The City’s climate is characterized by warm to hot summers and mild winters. The mean annual temperature and precipitation is 53° F and 7 inches, respectively. Table 3 summarizes the climatological data.

b. Soils The geological activity and USDA Web Soil Survey (WSS) was used to determine the Mabton’s soil characteristics. The area’s basic geology, described above, is not area specific. The aqua boundary line, shown in Figure 3 as an aqua rectangle, is the defined area of interest.

The majority of the soils inside this boundary are silt loams, a fact corroborated by the area geology; the remaining soils are predominantly sandy loams. Infiltration rates within this boundary are moderate, ranging from 0.13” per hour (silt loam) to 0.5” per hour (sandy loam). The majority of the area is well drained but rapid runoff events have been documented. Since the mean slope is 0-2% and annual precipitation is below 10 inches, rapid runoff is not likely to dominate storm events.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Average

Average Maximum

Temperature39.3 48.2 57.8 65.9 75.0 82.9 89.5 88.6 79.6 66.6 50.2 39.0 65.2

Average Minimum

Temperature23.5 28.1 33.1 39.1 46.6 54.0 58.9 57.5 48.4 37.6 30.8 23.7 40.1

Average Daily

Temperature31.4 38.1 45.5 52.5 60.8 68.5 74.2 73.0 64.0 52.1 40.5 30.4 52.7

Average

Precipitation (inch)1.00 0.64 0.64 0.51 0.50 0.46 0.21 0.39 0.40 0.44 1.01 1.15 7.33

Table 3. Monthly Climate Summary (City of Wapato, Data from Natural Resource Conservation Service

Climatological Data Summaries.)


August 2011


Figure 3. USDA Web Soil Survey Area of Interest Boundary. The aqua boundary depicts the survey

boundaries.

c. Ground and Surface Water

Groundwater wells serve the City’s potable water demands. Two chlorinated wells are equipped with pumps; the other two area wells are not equipped with pumps. Although there is no service connection moratorium, the Washington State Department of Health (WSDOH) issues operating permit is classified as Blue, which considers the supply inadequate for additional service connections. Additionally, according to the Yakima County Assessor’s records, the eastern City boundary poses moderate contamination risk to groundwater recharge1 (see Appendix D for Critical Aquifer Recharge Areas figure).

No wetlands or streams lie within the City of Mabton boundaries. Wetlands bordering the Yakima River fringe the northern UGA; additionally, a small Type 3 wetland (shallow marsh) is located in the far eastern portion of the UGA.

1 The Yakima County Assessor’s records were meant for planning purposes only and should not be considered a

legal assessment.


August 2011


B. Methodology

According to City of Mabton Wastewater Facility Plan (Gray & Osborne, Inc, 2011), the daily wastewater treatment plant flows are an estimated 173,000 gallons per day or 80 gallons/day-capita (GPCD). Some of this total is attributed to infiltration and inflow (I&I). For the purpose of this study, the estimated I&I is 6% of the daily treatment plant flows. The result is a decrease in per capita wastewater production to 75 GPD. Flow and usage rates provided by the AWWA Research Foundation’s Residential End Water Uses were applied to estimate the City’s daily flows for kitchen sinks, bathroom sinks, showers, a dishwasher, a clothes washer and toilets. Some usage rates were adjusted to match the 75 GPCD flow rate.

The goal of estimating realistic per capita usage rates was to ensure comparable results between conventional and sustainable strategies. Once these rates were assumed, they were applied throughout the sustainable strategies. All of the sustainable strategy flow estimates employed these comparable usage assumptions.

Water conservation does not negate the need for additional wastewater treatment capacity. User activities remain the same, resulting in similar daily loading (i.e. Ib. BOD/day). Conservation does reduce potable water treatment and conveyance energy requirement; wastewater conveyance costs (primarily in the treatment facility) can also be reduced. Users (households) could also benefit from decrease energy costs that are often associated with many of the fixtures identified in the following pages. Conservation has additional benefits not quantified in this study. Well water quality can be affected by water conservation. High demands sometimes require water to travel from greater distances in the aquifer, which increases the chance of land use practices contaminating the groundwater. The Critical Aquifer Recharge Areas map in Appendix C identifies the Mabton’s aquifer contamination susceptibility. Aquatic health also benefits from water conservation efforts. Fewer dams and reservoirs regulating the natural flow of rivers and streams would be required to control water sources. River and lake surface water withdrawals would decrease. Although Mabton currently does not use dams, reservoirs, or surface water withdrawals to serve potable water demands, conservation efforts could reduce any future needs.

C. Water Conservation

Plumbing Fixtures Retrofits:

Older, conventional fixtures typically consume greater volumes of water than newer (post 1992), low flow fixtures. Replacing fixtures can significantly reduce overall potable water demand.

• Shower heads – Typical non-conserving showerheads use as much as 5 gallons per minute (gpm) while a low flow shower head can use as little as 0.5 gpm. Using a shower head with a flow rate of 0.5 gpm for a typical 8 minute shower can reduce the showers water use from as high as 40 gallons to as little as 4 gallons.

• Bathroom faucets – Typical bathroom faucets use 2.5 gpm or more per minute while a low flow faucet will use as little as 0.5 gpm.

• Kitchen sink faucets - Flow rates can be reduced from an average of 2.5 gpm to as little as 1.5 gpm.

• Dishwashers – Flow rates can be reduced from an average of 10 gallons per load to as little as 1.5 gallons per load.

• Clothes washers – Flow rates can be reduced from an average of 40 gal/load to as little as 11 gal/load.

• Toilets – Old conventional toilets can use as much as 5 gallons per flush. Newer High Efficency Toilets (HET’s) use 1.28 gallons per flush while dual flush HET’s average as little as 0.9 gallons per flush. (A dual flush high efficiency toilet (HET) has two flush modes. A regular flush of 1.28 gallons for solid waste and as little as 0.8 gallons for liquids.)

Table 4 lists the estimated wastewater flows of all the sustainable strategies initially identified in this study. Each sustainable strategy maintains identical usage demands but fixtures or the source water changes (i.e. low flow fixtures or non-potable greywater for toilet flush), which


August 2011


modifies potable water volume demands and the resulting wastewater production. Itemized estimated demands for all 10 sustainable strategies are available in Appendix A.

Sustainable Water Efficiency Strategy Gallon/Day

-Capita (GPDC)

Percent Reduction

CURRENT MABTON AVERAGE DAILY FLOW (BASELINE) 75 -

WW1 LOW FLOW (FIXTURE RETROFIT) 41 45%

WW2 GREYWATER FLUSH 62 17%

WW3 LOW FLOW/ GREYWATER FLUSH 36 52%

WW4 LIGHT GREYWATER IRRIGATION 53 29%

WW5 ALL GREYWATER IRRIGATION 44 41%

WW6 LOW FLOW/ LIGHT GREYWATER IRRIGATION 28 62%

WW7 LOW FLOW/ ALL GREYWATER IRRIGATION 23 70%

WW8 LOW FLOW/ GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION 26 65%

WW9 LOW FLOW/ GREYWATER FLUSH/ ALL GREYWATER IRRIGATION 20 73%

WW10 DECENTRALIZED TREATMENT AND WATER REUSE 0 100%

Table 4.Sustainable Water Efficiency Strategy Summary. Lists the per capita daily estimated wastewater flow to

the Mabton wastewater treatment facility (WWTF) and the associated percent flow reduction yielded from the various

scenarios.


August 2011


1. WW1- LOW FLOW (FIXTURE RETROFIT)

Flow Reduction:

Sustainable Strategy WW1 maintains the City’s water supply and usage rates; however, this scenario assumes that all fixtures are or will be replaced with low flow fixtures and/or appliances. Figure 4 diagrams the water flows in this scenario. Potable water demand and wastewater production for WW1 are listed in Table 5. As indicated in Table 5, retrofitting standard city fixtures to low flow fixtures yields average potable water demand and wastewater flow reductions by an estimated 45%. Assuming nearly 531 housing units and 4.08 persons per housing unit, this equates to annual potable water savings of approximately 82.5 acre-ft/year (or 3.6 million CF/year).

Sustainability Strategy: WW1 LOW FLOW (FIXTURE RETROFIT)

Town Low Flow Town Low Flow

Shower 2.20 1.50 gpm 8 min/day 17.6 12.00 32%

Bathroom Sink 2.00 1.25 gpm 7 min/day 14.00 8.75 38%

Kitchen Sink 2.50 1.50 gpm 7 min/day 17.50 10.50 40%

Dishwasher 10.00 4.00 gal/load 0.1 loads/day 1.00 0.40 60%

Clothes Washer 40.00 15.00 gal/load 0.3 loads/day 12.00 4.50 63%

Toilet 2.56 0.95 gal/flush 5 flush/day 12.79 4.75 63%

75 41 45%

75 41 45%

(1) Town daily wastewater production estimate derived using 80 gpcd wastewater flow from City of Mabton Wastewater Facility

Plan and assuming 6% I&I.

Usage

UnitsUsage

Flow Rate Flow

UnitsUsage

Estimated Wastewater Production Per Person1:

Estimated Potable Water Demand Per Person1:

Reduction From

Typical Town Flow

Total Use Per Person

(gal/day)

Figure 4. WW1-Low Flow (Fixture Retrofit)

Flow Diagram.

Table 5. WW1- Low Flow (Fixture Retrofit) Estimate. Compares conventional and low flow fixture potable water demands and wastewater production contributing to treatment plant influent flows.


August 2011


Cost Estimate:

Table 6 itemizes retrofit costs for (1) each residential unit ($2,335) and (2) the entire city ($1,239,460). The retail cost outlined below includes installation. The cumulative value was applied to cost of ownership estimate as the capital cost (Figure 5). According to the City of Mabton Comprehensive Water Plan, approximately $308,356 in 2008 to operate and maintain the potable water system (see Appendix D). If 694.72 acre-ft are consumed annually, the cost associated to treat and convey each acre-ft is $444 (or $0.0014/gallon).

Table 6. WW1 Cost Estimate. Transparent list of material and installation cost estimates for each fixture.

Water Rights:

Water Rights costs range from $2,000-$6,000/acre-ft. An average cost of $4,000/acre-ft was assumed for this study. If approximately 694.72 acre-ft are currently consumed annually, an 82.5 acre-ft savings equates to $330,000 savings (avoided cost of purchasing additional Water Rights).

2 2009 Water-Right Self-Assessment Form, 2005 City of Mabton Comprehensive Water Plan (Revised), Appendix 8

Estimated Cost: WW1 LOW FLOW (FIXTURE RETROFIT)

FixtureCost/

Fixture

Fixtures/

Housing Unit

Household

Fixture Cost

Installation Cost/

Fixture

Household

Installation CostTotal Cost

Showerhead $20.00 2 $40.00 $35.00 $70.00 $110.00

Faucet Aerators $4.00 3 $12.00 $0.00 $0.00 $12.00

Dishwasher $600.00 1 $600.00 $100.00 $100.00 $700.00

Clothes Washer $750.00 1 $750.00 $50.00 $50.00 $800.00

Toilet $150.00 2 $300.00 $100.00 $200.00 $500.00

$1,702.00 $420.00 $2,122.00

$212.20

$2,334.20

$1,239,460.20

installation costs from

http://www.homewyse.com/services/index.html

Cost Per Housing Unit

Total Cost - 531 Housing Units

10% Contingency

Total Cost Per Housing Unit

An 82.5 acre-ft/year annual water savings (26.9 million gallons/year) reduces operating and maintenance costs approximately $37,640/year (present value).


August 2011


Figure 5. WW1 Estimated Cost of Ownership

Water and Energy Alternatives

Water Efficiency

Sustainability Strategy: WW1 - LOW FLOW (FIXTURE RETROFIT)

Inflation Rate: 2.3%

CapitalAnnual

O&M

Total

Present5-Year 10-Year 25-Year 50-Year

BASELINE

Total System Costs $330,000 $308,356 $638,356 $2,287,381 $4,130,460 $11,066,128 $29,253,689

Operating and Maintenance Costs $308,356 $308,356 $1,957,381 $3,800,460 $10,736,128 $28,923,689

ALTERNATIVE

Total System Costs $1,239,460 $270,716 $1,510,176 $2,957,910 $4,576,011 $10,665,065 $26,632,530

Operating and Maintenance Costs $270,716 $270,716 $1,718,450 $3,336,551 $9,425,605 $25,393,070

Assumptions:

0

10

25

50

Notes:

Total Present 5-Year10-Year 25-Year50-Year

$638,356 $4,130,460 $29,253,689

$1,510,176 $4,576,011 $26,632,530

ESTIMATED COST OF OWNERSHIP

`

MABTON GREEN PROJECT

5. Inflation rate listed is 5-year average (2006-2010).

4. Estimate potable w ater treatment and conveyance cost

derived from 2008 operating and maintenance costs

($308,356) and estimated usage (694.7 acre-ft). Both

estimates w ere obtained from the City of Mabton

Comprehensive Water System Plan.

1. Current Water use is approximately 75 GPD-person.

4. Above costs do not include any w astew ater treatment

costs.

COST SCHEDULED COST OF OWNERSHIP

2. 34 GPD-person savings equates to 26.9 million

gallons/year (or 82.5 acre-ft/year savings).

1. Operation and maintenance (O&M) costs, include w ater

right aquisition and treament costs.

3. Treatment to potable w ater standards and conveyance of

potable w ater cost is $0.0014/gallon.

2. Capital costs include initial material and installation costs.

3. Retrofit capital costs includes material and installation

costs for 2 show er heads, 3 faucet aerators, 1 dishw asher,

1 clothes w asher, and 2 toilets for each residential unit (518

units).

$0

$5,000,000

$10,000,000

$15,000,000

$20,000,000

$25,000,000

$30,000,000

$35,000,000

Total Present 5-Year 10-Year 25-Year 50-Year

Co

st ($

)

Time (Year)

Forecasted Operating and Maintenance Costs

ALTERNATIVE

BASELINE

$0

$5,000,000

$10,000,000

$15,000,000

$20,000,000

$25,000,000

$30,000,000

$35,000,000

TotalPresent

5-Year 10-Year 25-Year 50-Year

Co

st

($)

Time (Years)

Scheduled Cost of Ownership

ALTERNATIVE

BASELINE


August 2011


D. Water Reuse and Decentralized Wastewater Treatment

Greywater irrigation systems below 3,500 GPD are permitted through Chapter 246-274 WAC, which is a three tiered permitting approach based on greywater source, storage, quantity, treatment and distribution. Table 5 summarizes the system characteristics of each tier.

Project Type

Greywater Source

Storage Quantity Treatment and Distribution

Tier 1 Light Greywater1

None <60 GPD-irrigation system, 2 systems max per household

No treatment; gravity distribution

Tier 2 Light Greywater1

24 hour <3,500 GPD No treatment; even distribution

Tier 3 Dark Greywater2

No limit <3,500 GPD Treatment required; even distribution

Table 7. Chapter 246-274 WAC Greywater Reuse for Subsurface Irrigation. 1Light greywater is defined as wastewater from sinks, showers, tubs and clothes washing machines

2Dark greywater is defined as all combined greywater that does not contact toilet or urinal wastes

Sustainable strategies WW6 and WW8 are composed of light greywater sources but since flows exceed 60 GPD, both strategies fall within Tier 2 guidelines. Sustainable strategy WW10 has dark greywater sources and exceeds 3,500 GPD. Therefore, it should be permitted under Chapter 246-272 WAC (Large Onsite Sewage Systems).

The following charts illustrate potable water demand and wastewater flow reductions attainable by changing from the assumed typical city fixture flow rates to water saving scenarios that incorporate water reuse and decentralized treatment options. Typical city flow rates and usage were calculated by using flow rates and usage information provided by “Residential End Water Uses” by the AWWA Research Foundation and American Water Works Association and altering them to fit the 80gpcd from table 4-2 (page 4-4) of the City of Mabton Wastewater Facility Plan by Grey and Osborne, Inc.


August 2011


2. WW6- LOW FLOW/ LIGHT GREYWATER IRRIGATION

Flow Reduction:

Similar to WW1, Sustainable Strategy WW6 maintains the City’s water supply and usage rates; it also assumes that the housing units will be retrofitted with low flow fixtures. Conversely, it does not utilize the City’s potable water supply for all fixtures. Instead non-potable greywater from sinks and showers is used for seasonal irrigation; any daily remaining greywater balance will be diverted to the City’s sanitary sewer system. Figure 6 diagrams the water flows in this scenario.

Table 8 (Sustainable Strategy WW6) compares the City’s current scenario with a low flow fixture, greywater diversion scenario. Potable water demand and wastewater production estimates for both scenarios (current and WW6) are included in the table. Since the average irrigation season is 6 months in eastern Washington State, the annual average wastewater flow is 28 GPD-capita. During the summer, non-potable greywater is used for subsurface irrigation (approximately 760 ft2 landscaped area irrigated per household unit) and the wastewater treatment plant flows decrease to 16 GPD-capita.

Table 8. Flow Estimates Using Light Greywater for Irrigation. Compares conventional and low flow

fixture potable water demands and wastewater production contributing to treatment plant influent flows when

light greywater is used for seasonal irrigation.

Sustainability Strategy: WW6 LOW FLOW/ LIGHT GREYWATER IRRIGATION

TownLow Flow/ Light

Greywater IrrigationTown

Light Greywater

Irrigation

Shower 2.20 1.50 gpm 8.00 min/day 17.6 12.00 32%

Bathroom Sink 2.00 1.25 gpm 7.00 min/day 14.00 8.75 38%

Kitchen Sink 2.50 1.50 gpm 7.00 min/day 17.50 10.50 40%



Toilet 2.56 0.95 gal/flush 5.00 flush/day 12.79 4.75 63%

75 41 45%

0.00 -25.25

75 16 79%

75 28 62%

(1) Town daily wastewater production estimate derived using 80 gpcd wastewater flow from City of Mabton Wastewater Facility Plan and

assuming 6% I&I.

Reduction

From Typical

Town Flow

Estimated Wastewater Production Per Person During Irrigation Season1:

Usage

Flow Rate

Greywater Irrigation:

Flow

UnitsUsage

Usage

Units

Total Wastewater Production

Estimated Annual Wastewater Production Per Person1:


Figure 6. WW6-Low Flow/Light Greywater Irrigation

Diagram.


August 2011


Cost Estimate:

Table 8 itemizes retrofit costs for (1) each residential unit ($3,516.70) and (2) the entire city ($1,867,367.70). Each residential unit would need to install a small greywater irrigation unit, which includes both a filter and drip disposal system. Greywater irrigation unit cut sheets are available in Appendix B. The retail cost outlined below includes installation. The cumulative value was applied to Cost of Ownership Estimate as the capital cost (Appendix A).

Water Rights:

Water Rights costs range from $2,000-$6,000/acre-ft. An average cost of $4,000/acre-ft was assumed for this study. If approximately 694.73 acre-ft are currently consumed annually, an 82.5 acre-ft savings equates to $330,000 savings (avoided cost of purchasing additional Water Rights).


Estimated Cost: WW6 LOW FLOW/ LIGHT GREYWATER IRRIGATION

FixtureCost/

Fixture

Fixtures/

Housing Unit

Household

Fixture Cost

Installation Cost/

Fixture

Household


Showerhead $20.00 2 $40.00 $35.00 $70.00 $110.00

Faucet Aerators $4.00 3 $12.00 $0.00 $0.00 $12.00

Dishwasher $600.00 1 $600.00 $100.00 $100.00 $700.00

Clothes Washer $750.00 1 $750.00 $50.00 $50.00 $800.00

Toilet $150.00 2 $300.00 $100.00 $200.00 $500.00

Greywater Irrigation Unit $875.00 1 $875.00 $200.00 $200.00 $1,075.00

$2,577.00 $620.00 $3,197.00

$319.70

$3,516.70

$1,867,367.70


10% Contingency



Table 9. WW6 Cost Estimate. Transparent list of material and installation cost estimates for each fixture and

treatment method.



August 2011


3. WW8- LOW FLOW/GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION

Sustainable strategy WW8 uses greywater from sinks, showers, and the clothes washer to flush toilets and irrigate outdoor vegetation. The City’s potable water system maintains its status as the primary water supply for potable water fixtures; however, non-potable fixtures (toilet flush and irrigation) use non-potable greywater as the main water source. A greywater treatment system is required to treat greywater to reuse standards. Figure 7 depicts the household water flow. Table 10 (Sustainable strategy WW8) compares the potable water demand and wastewater production volumes for City’s current flows against WW8. Potable water demand is

reduced by 52%, equating to approximately 30.9 million gallons/year (94.7 acre-ft/year).

Table 10. Using Light Greywater Produced from Low Flow Fixtures for Toilet Flush and Irrigation.

Compares conventional and low flow fixture potable water demands and wastewater production contributing to

treatment plan influent flows when light greywater is used for toilet flush and seasonal irrigation.

Sustainability Strategy: WW8 LOW FLOW/ GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION

TownLow Flow/

Greywater Flush/ Town

Low Flow/

Greywater Flush/







Greywater Toilet Flush 0.00 -0.95 gal/flush 5 flush/day 0.00 -4.75

75 36 52%

0.00 -25.25

75 16 79%

75 26 65%


Usage

Flow Rate


assuming 6% I&I.


Flow

UnitsUsage

Usage

Units

Reduction

From Typical

Town Flow




Figure 7. WW8-Low Flow/Greywater Toilet Flush/

Light Greywater Irrigation Diagram.


August 2011


Cost Estimate:

Table 11 includes material and installation costs for (1) each house ($9,570) and (2) the entire city ($5,079,920). Each house would need to install a small greywater irrigation unit, which includes both a filter and drip disposal system. The retail cost outlined below includes installation. Because subsurface irrigation has less stringent filtration requirements, a second greywater filtration unit would be required to re-use greywater for toilet flush. These additional costs (over the base retrofit costs) were applied to cost of ownership estimate as the capital cost (Appendix A).

Table 11. WW8 Cost Estimate. Transparent list of material and installation cost estimates for each fixture and

treatment method.

Water Rights:

Water rights costs range from $2,000-$6,000/acre-ft. An average cost of $4,000/acre-ft was assumed for this study. If approximately 694.74 acre-ft are currently consumed annually, an 94.7 acre-ft savings equates to $378,800 savings (avoided cost of purchasing additional Water Rights).


Estimated Cost: WW8 LOW FLOW/ GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION

FixtureCost/

Fixture

Fixtures/

Housing Unit

Household

Fixture Cost

Installation Cost/

Fixture

Household


Showerhead $20.00 2 $40.00 $35.00 $70.00 $110.00

Faucet Aerators $4.00 3 $12.00 $0.00 $0.00 $12.00

Dishwasher $600.00 1 $600.00 $100.00 $100.00 $700.00

Clothes Washer $750.00 1 $750.00 $50.00 $50.00 $800.00

Toilet $150.00 2 $300.00 $100.00 $200.00 $500.00

Greywater Irrigation Unit $875.00 1 $875.00 $200.00 $200.00 $1,075.00

Greywater Treatment Unit $3,500.00 1 $3,500.00 $2,000.00 $2,000.00 $5,500.00

$6,077.00 $2,620.00 $8,697.00

$869.70

$9,566.70

$5,079,917.70

10% Contingency






August 2011


4. WW10- DECENTRALIZED TREATMENT AND WATER REUSE

Flow Reduction: As depicted in Figure 8, City supplied potable water system supplies water to all fixtures and appliances except the toilets. The resulting wastewater is treated in neighborhood scale decentralized wastewater treatment facilities (5,000 GPD). The systems will treat wastewater to reclaimed water standards, which will then be used indoors for toilet flush. The remaining water balance will be disposed in subsurface drip irrigation systems. The well drained soils have moderate infiltration rates (see Introduction section B.2) makes the City a feasible candidate for subsurface dripline disposal. Table 11 compares the potable water demand and wastewater production rates for assumed typical city flows with the potable water demand and wastewater production rates for a scenario using multiple 5,000 gal decentralized wastewater treatment facilities.

Sustainability Strategy: WW10 DECENTRALIZED TREATMENT

CurrentDecentralized

TreatmentCurrent

Decentralized

Treatment

Shower 2.20 1.50 gpm 8 min/day 17.6 12.00 32%

Bathroom Sink 2.00 1.25 gpm 7 min/day 14.00 8.75 38%

Kitchen Sink 2.50 1.50 gpm 7 min/day 17.50 10.50 40%



Toilet 2.56 0.95 gal/flush 5 flush/day 12.79 4.75 63%


75 36 52%

0 -36

75 0 100% Estimated Wastewater Production Per Person 1 : (1) Town daily wastewater production estimate derived using 80 gpcd wastewater flow from City of Mabton Wastewater Facility Plan and

assuming 6% I&I.

Usage

Flow to Decentralized Wastewater Treatment

Estimated Potable Water Demand Per Person1 :

Reduction

From Typical

Town Flow

Flow RateFlow

UnitsUsage

Usage

Units


Per Person (gal/day)

Figure 8. WW10 Decentralized Wastewater

Treatment Diagram.

Table 12. Neighborhood Scale Treatment System Flow Estimate. Compares the City’s current contributing

wastewater flows with decentralized treatment and water reuse contributing flows.


August 2011


Cost Estimate:

Table 13 includes material and installation costs for (1) each residential unit ($11,900) and (2) the entire city ($6,321,150). Cost estimates for two different decentralized treatment systems were obtained (an Advantex Treatment System and an Aquacell Membrane Bioreactor). This price estimate includes low flow fixture retrofits, decentralized treatment unit costs, system connection costs, and drip irrigation drainfield disposal costs. It is assumed that the treatment units would be placed on public property so land costs are not included in the estimate. Post treatment, the water will be disinfected and conveyed back to the housing units for toilet flush. Capital costs from the unit to the housing units are included in the cost estimate. The existing sanitary sewer conveyance system can be retrofitted and used to convey wastewater flows to the decentralized treatment unit. Therefore, conveyance costs from the housing to the treatment units are not included in the estimate. Capital costs for the drip field irrigation system are included, which will irrigate 36,960 ft2 of public lands in each neighborhood scale treatment area. The Cost of Ownership for the decentralized treatment and disposal system is available in Appendix A.

Table 13. WW10 Cost Estimate. Decentralized, neighborhood scale treatment and water reuse system cost estimate

Water Rights:

Water Rights costs range from $2,000-$6,000/acre-ft. An average cost of $4,000/acre-ft was assumed for this study. If approximately 694.75 acre-ft are currently consumed annually, an 94.7 acre-ft savings equates to $378,800 savings.


Estimated Cost: WW10 DECENTRALIZED TREATMENT

FixtureCost/

Fixture

Fixtures/

Housing Unit

Household

Fixture Cost

Installation Cost/

Fixture

Household


Showerhead $20.00 2 $40.00 $35.00 $70.00 $110.00

Faucet Aerators $4.00 3 $12.00 $0.00 $0.00 $12.00

Dishwasher $600.00 1 $600.00 $100.00 $100.00 $700.00

Clothes Washer $750.00 1 $750.00 $50.00 $50.00 $800.00

Toilet $150.00 2 $300.00 $100.00 $200.00 $500.00

Decentralized Treatment Unit $4,000.00 1 $4,000.00 $200.00 $200.00 $4,200.00

Connection Cost - 1 - $2,000.00 $2,000.00 $2,000.00

Dripfield Conveyance $2,500.00 1 $2,500.00 $0.00 $0.00 $2,500.00

$8,202.00 $2,620.00 $10,822.00

$1,082.20

$11,904.20

$6,321,130.20


10% Contingency





August 2011


E. Summary (Part 1: Water Efficiency)

A number of different sustainable water efficiency strategies can effectively conserve potable water and subsequently reduce wastewater volumes produced. This report focuses on four principle sustainable strategies which could be implemented by the City of Mabton as part of their Water Conservation Program and to help meet their Green Project goals.

Figure 1 provides a visual comparison of the potable demands and treatment plant flows among the different sustainable water efficiency strategies.

Summary of the four principle sustainable strategies:

• WW1-Low Flow Fixture Retrofit replaces conventional fixtures with low flow fixtures, reducing average demand and production by 45% compared to the estimated daily per capita treatment plant flows. Estimated retrofit costs for (1) each residential unit are $2,335 and (2) the entire city $1,239,460.

• WW6-Low Flow/Light Greywater Irrigation uses the light greywater produced from the low flow fixtures for seasonal irrigation, successfully reducing average potable demands and treatment plant flows by 45% and 62%. Estimated costs for (1) each residential unit are $3,520 and (2) the entire city $1,867,370.

• WW8-Low Flow/Greywater Flush/Light Greywater Irrigation uses all greywater and light greywater from the low flow fixtures for toilet flush and seasonal irrigation, respectively; average potable demands and treatment plant flows by 52% and 65%. Estimated material and installation costs for (1) each residential unit are $9,560 and (2) the entire city are $5,079,920.

• WW10-Decentralized Treatment and Water Reuse removes all wastewater flows to the treatment plant by instituting small scale, decentralized treatment systems; with low flow fixtures, average potable water demands are reduced by 52% and wastewater flows to the treatment plant are reduced by 100%. Estimated material and installation costs for (1) each residential unit are $11,904 and (2) the entire city is $6,321,150.

Figure 9.

Potable Water Demand vs. Wastewater Production. The figure provides a comparison between the potable water demands with wastewater flowing to the treatment plant. The difference between the blue (potable water) and beige (wastewater) bars is the volume of household greywater use.


August 2011


Example Sustainable Water Efficiency Analysis:

Sustainable strategy WW8-Low Flow/Greywater Flush/ Light Greywater Irrigation uses greywater from sinks, showers, and the clothes washer to flush toilets and irrigate outdoor vegetation. The City’s potable water system maintains its status as the primary water supply for potable water fixtures; however, non-potable fixtures (toilet flush and irrigation) use greywater as the main water source. A greywater treatment system is required to treat greywater to reuse standards.

The table below (Sustainable strategy WW8) compares the potable water demand and wastewater production volumes for City’s current flows against WW8. Potable water demand is reduced by 52%, equating to approximately 30.9 million gallons/year (94.7 acre-ft/year).

Sustainability Strategy: WW8 LOW FLOW/ GREYWATER FLUSH/ LIGHT GREYWATER IRRIGATION

TownLow Flow/

Greywater Flush/ Town

Low Flow/

Greywater Flush/








75 36 52%

0.00 -25.25

75 16 79%

75 26 65%

Reduction

From Typical

Town Flow




Flow

UnitsUsage

Usage

Units


assuming 6% I&I.



Usage

Flow Rate

Example Flow Diagram (WW8)

Example Flow Summary (WW8)


August 2011


Table 14 and Figure 10 both compare and project various wastewater reduction strategies. The red, dashed line represents the WWTF maximum loading rate. It should be noted that wastewater flow reductions do not necessarily correspond to wastewater load reductions. Flow reductions will not negate the need for additional treatment capacity.

Table 14. Projected Population and Flows for Various Sustainable Water Efficiency Strategies.

Figure 10. Projected Flow Comparison for Various Sustainable Water Efficiency Strategies.

WW1 WW6 WW8 WW10

Year PopulationProjected Flow Low flow

Fixtures

Low Flow/Light

Grey for Toilet

Flush & Irrigation

All Greywater for

Toilet Flush &

Irrigation

Decentralized

Treatment

Processes

2010 2,165 0.173 NA NA NA NA

2012 2,250 0.180 0.180 0.180 0.180 0.180

2013 2,293 0.183 0.094 0.036 0.036 0.083

2015 2,378 0.190 0.097 0.037 0.037 0.086

2020 2,575 0.206 0.105 0.040 0.040 0.093

2025 2,772 0.222 0.113 0.043 0.043 0.100

2030 2,986 0.239 0.122 0.047 0.047 0.108

2031 3,031 0.242 0.124 0.047 0.047 0.110

WASTEWATER REDUCTION SCENARIOS

(MGD)

CURRENT

PROJECTION

(MGD)


August 2011


Part 2: Energy Efficiency (Natural Wastewater Treatment Alternatives)

A. Introduction

The purpose of this portion of the report is to present a low energy alternative to upgrade to the wastewater management system for the City of Mabton, Washington. The ideal wastewater management system will provide effective treatment with low energy input, while also providing an attractive system with wetlands and wildlife habitat.

A range of low energy wastewater treatment alternatives were evaluated for the City of Mabton WWTF upgrade. The alternatives evaluated range from limited discharge systems with no energy required to multi-stage process requiring aeration, pumping and mixing. Of the alternatives evaluated, a three-stage system was selected as the best overall alternative. These selected alternatives are described below. A discussion of the full range of alternatives is presented in subsequent sections.

B. Natural Treatment Systems (Overview)

Natural treatment systems can be entirely passive, which results in the least energy inputs and the greatest land requirements. Natural systems can also be supplemented with mechanical aeration systems, which drastically reduces the land area required but increases the power consumption. This study has evaluated both “passive” and “intensified” alternatives for both the lagoon and wetland stages of the overall treatment process. This study concludes that a combination of lagoons and wetlands would provide the optimal combination of a low-energy natural treatment system for the City of Mabton. Lagoon systems have been demonstrated to be more effective in handling organic loading and flow variations, while wetland systems have been demonstrated to be more effective at achieving low effluent concentrations (Kadlec, 2004). Combining these two natural systems into a staged pond-wetland process results in an overall treatment train capable of processing high organic loads and achieving low effluent concentrations. This report presents an initial preliminary evaluation of low-energy wastewater treatment alternatives for the City of Mabton. These evaluations are based on meeting design criteria listed in Table 15 and Table 16 as the minimum. Additional treatment for nitrogen removal to 10 mg/L is also evaluated along with options for phosphorus removal to <1 mg/L.

1. Lagoon Options

Lagoon-based treatment systems suitable for the City of Mabton could be entirely passive (facultative lagoons), or mechanically aerated (partial-mix aerated lagoons). Facultative Lagoons:

In the case of facultative lagoons in Mabton’s climate, an organic loading rate (BOD) of 30 kg/ha-d is appropriate (Crites et al., 2006), given the temperature range over the coldest 6 months of the year (41.5°F). This equates to a lagoon area of 26.8 acres with a depth of 5 feet (likely subdivided into 3 subsections), and a hydraulic residence time (HRT) in excess of 145 days. This system would be capable of achieving 30 mg/L BOD5 and 30 mg/L TSS as an initial treatment stage. A typical facultative lagoon is shown in Figure 10.


August 2011


Figure 11. Typical Facultative Lagoon

Because a facultative lagoon is entirely passive, there is zero mechanical/electrical energy input. Aerated Lagoons:

Aerated lagoons are designed to be much smaller and compact than facultative lagoons. They rely on mechanical aeration systems to satisfy the oxygen demand required for wastewater treatment, and often have internal baffle curtains to improve hydraulics and treatment efficiency. In the case of Mabton, a partially aerated lagoon would be approximately 4 acres in size, with a depth of 10 feet (Alternative B). The partially aerated lagoon would likely use a combination of fine bubble aeration and mixers to achieve required oxygen transfer and mixing. The aerated lagoon would likely have two separate cells, each with an internal baffle curtain (creating four separate compartments overall). The system would be capable of achieving 30 mg/L BOD5 and 30 mg/L TSS as an initial treatment stage. The aerated lagoon option has been sized according to Rich (1999).


August 2011


2. Wetland Options

Constructed wetlands are a treatment technology that have been applied for over 40 years. There are several types of constructed wetlands:

� Surface flow wetlands, which function as man-made equivalents of natural marshes.

These systems typically have a water depth of approximately 12 inches, and support a plant community of emergent wetland plants like cattails and bulrushes (Figure 11). These systems have the highest wildlife habitat and recreational values.

� Horizontal subsurface flow wetlands, which consist of a gravel bed. Water flows horizontally in the gravel bed through the root zone of the wetland plants (typically reeds). Since the water is kept below the surface of the gravel, these systems are preferred when exposed open water would be a problem or in sub-freezing climates.

� Vertical flow wetlands, which consist of a gravel bed to which water is intermittently dosed and flows vertically through the root zone of the wetland plants. These systems are preferred in limited land areas, but have a higher energy input than surface flow or horizontal subsurface flow wetlands.

� Sludge dewatering reed beds use a planted sand filter to stabilize biosolids resulting from wastewater treatment (Figure 12).

For the City of Mabton, the cost of aggregate may be prohibitively expensive for the horizontal subsurface flow and vertical flow wetland options. Given the relatively high flow rate (290,000 gallons per day for the maximum month), a surface flow wetland system. A surface flow wetland would also maximize wildlife habitat value, and is aligned with the City’s ecotourism goals is recommended.

Surface Flow Wetland Alternatives:

Like lagoons, wetlands can be intensified to improve treatment efficiency and minimize land area. Given the range of scenarios and treatment alternatives requested by the City of Mabton, the surface flow wetland sizing could range from 0.2 acres to 120 acres, depending on the alternative selected. Sizing alternatives are broken down for each scenario in subsequent sections of this report.


August 2011


Figure 12. Surface Flow Wetland Adjacent to Venice, Italy

Figure 13. Sludge Dewatering Reed Ben, Pine River, Minnesota


August 2011


C. Wastewater Description and Discharge Standards

Wastewater flows and loads for the future treatment facility have already been defined, and are summarized in Table 15:

Flow or Loading Projected Design Value

Sewer Service Population 3,031

Average Annual Flow (MGD) 0.24

Maximum Month Flow (MGD) 0.29

Maximum Day Flow (MGD) 0.69

Peak Hour Flow (MGD) 0.87

Annual Average BOD5 Loading (lb/d) 515

Maximum Month BOD5 Loading (lb/d) 697

Annual Average TSS Loading (lb/d) 455

Maximum Month TSS Loading (lb/d) 727

Maximum Month TKN Loading (lb/d) 155

Minimum Design Wastewater Temperature 7°C

Maximum Design Wastewater Temperature 29°C

Table 15. 2031 City of Mabton Design Criteria

Discharge Standards:

Discharge standards for the next permit cycle have already been defined by the Washington Department of Ecology and are summarized in Table 16. These are assumed to represent the “tertiary” treatment standards alternative requested by the City of Mabton.


BOD5 N/A 10 mg/L, 24.2 lb/day,

85% removal of influent BOD 15 mg/L, 40.7 lb/day

TSS N/A 30 mg/L, 72.6 lb/day,

85% removal of influent TSS 45 mg/L, 122 lb/day


pH Daily minimum is equal to or greater than 6 and

the daily maximum is less than or equal to 9


Total Ammonia (as NH3-N)

4.5 mg/L 2.9 mg/L N/A

Temperature Shall cause less than a 0.3°C temperature

rise at the edge of the mixing zone

Table 16. City of Mabton Projected NPDES Permit Effluent Limits (Next Permit Cycle)

As required in the NPDES Permit WA-002064-8, the alternative evaluation is required to evaluate how to increase the oxygen level in the effluent. The alternatives proposed must provide aeration prior to discharge to increase the effluent oxygen level to 10 mg/L. This is addressed in a following section of this evaluation.


August 2011


Fecal Coliform Standards:

The low energy treatment alternatives would likely meet discharge requirements for fecal coliform by the disinfection method proposed in the conventional upgrade evaluation (UV system). The effluent from any of the alternatives would be suitable for ultraviolet light disinfection to meet a discharge limits for fecal coliform. The cost and power requirements for disinfection were taken from information provided by Grey & Osborne from their WWTF upgrade recommendations. Future Nutrient Removal:

The low energy treatment alternative shall be able to meet a future projected permit limit of 10 mg/L for Total Nitrogen (TN). The facility shall be capable of being modified to meet a future phosphorus limit which might be less than 1 mg/L.

City of Mabton Location and Climate:

The City of Mabton is located in central Washington State in the Yakima River valley. The City is currently serviced by a mechanical wastewater treatment plant (Figure 13), although large amounts of agricultural land surrounds the City (Figure 13). Given the presence of ample land around the City and the existing WWTF, it appears that natural treatment systems (lagoons and wetlands) could be employed as low energy treatment alternatives. Because these systems operate on natural ecosystem processes, climate is an important component in determining how these systems will function. One of the most important parameters is temperature. Temperature data from 2010 for the City of Mabton (weather station KWAMABTO1) is summarized in Figure 14:

Figure 14. City of Mabton 2010 Average Monthly Temperatures

30

35

40

45

50

55

60

65

70

75

80

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Te

mp

era

ture

, oF

Mabton, Washington2010 Average Monthly Temperatures


August 2011


As shown in Figure 13, during 2010 the maximum average monthly temperature occurred in July (73.2˚F), and the minimum monthly average temperature occurred December (35.3˚F). This has important consequences for the design of natural treatment systems. Due to the long hydraulic residence times present in most lagoon and wetland systems, the water temperature will equilibrate to the average monthly air temperature (Kadlec and Wallace, 2009).

Another important factor influencing the design of natural treatment systems is the relative ratio of precipitation (P) vs. evaporation, or evapotranspiration (ET), in the case of wetlands (due to the presence of vegetation). Mabton is a relatively arid region; in 2010 the City only received 7.46 inches of rainfall. This was compared against long-term monthly pan evaporation data (45.8 inches per year) from the nearby City of Prosser (obtained from the Washington State University PAWS web site). Pan evaporation was corrected to wetland evapotranspiration by a factor of 0.8, which has been confirmed in several wetland studies (Kadlec and Wallace 2009). The relative difference in precipitation vs. wetland evapotranspiration is shown in Figure 15:

Figure 15. City of Mabton Net Water Gain/Loss by Month

The data shown in Figure 15 indicates that there were only two months – February and December, when precipitation exceeded wetland evapotranspiration, and that the maximum net water loss (-6.9 inches) occurred in the month of July. The cumulative annual net water balance is -30.7 inches, indicating that a wetland without any external inputs of water would lose 30.7 inches of water per year just due to climate effects.

-8

-7

-6

-5

-4

-3

-2

-1

0

1

2

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Wa

ter

Ga

in/

Lo

ss,

inch

es/

mo

nth

Mabton, WashingtonNet Water Gain/Loss (P-ET) per Month


August 2011


D. Low Energy Wastewater Treatment Alternatives

The low energy wastewater treatment alternatives evaluated in this report both have first stages that achieve secondary treatment – BOD5 of 25 mg/L and TSS of 30 mg/L. The first stages would need to be followed by further treatment to achieve the ammonia discharge limits in winter. The initial treatment stage would be a lagoon – either the facultative lagoon option or the aerated lagoon option. Either lagoon system would be capable of meeting approximately the same effluent standards (30 mg/L BOD, 30 mg/L TSS). The water discharged from the lagoon would then be polished in a surface flow wetland designed to meet a BOD5 of 13.8 mg/L, which should be sufficient for final treatment to meet the discharge standards for BOD, TSS and Ammonia.

1. Facultative Lagoon and Surface Flow Wetland

Alternative A-1 – Secondary Treatment ONLY- Facultative Lagoon + Surface Flow Wetland

Energy for Facultative Lagoon Treatment: 0 Energy for Surface Flow Wetland Treatment: 62,800 kW-hr per year Land Requirement: 28 acres (22 for lagoon + 6 for wetland) Discharge Standard 25 mg/L BOD5, 30 mg/L TSS

Note: Polishing and ammonia removal are presented in following section

2. Aerated Lagoon and Surface Flow Wetland

Alternative B-1 – Secondary Treatment ONLY-Aerated Lagoon + Surface Flow Wetland

Energy for Aerated Lagoon Treatment: 300,000 kW-hr per year Energy for Surface Flow Wetland Treatment: 62,800 kW-hr per year Land Requirement: 9.7 acres (4 for lagoon + 5.7 for wetland) Discharge Standard 25 mg/L BOD5, 30 mg/L TSS

Note: Polishing and ammonia removal are presented in following section

Either Scenario A-1 or B-1 require additional treatment to meet the future permit limits for ammonia that the Department of Ecology intends to impose on the City of Mabton (A-2 and B-2 alternatives, see Figures 15 and 17).

3. Aerated Gravel Bed: Third Stage Polishing/Ammonia Removal

The major challenge under the of the upcoming discharge requirements is meeting the average monthly ammonia limit under winter conditions, when the water temperature could be as low as 2°C (35.6°F). This requires either an enlarged surface flow wetland or a third stage treatment system. In order to meet the ammonia standard of 2.9 mg/L 90% of the time, a surface wetland would have to be designed to discharge 1.6 mg/L of ammonia. This analysis indicates that a non-aerated (passive) surface flow wetland cannot meet this standard (the wetland size at 2°C exceeds the area needed for the zero-discharge option).

One possible approach would be an aeration-enhanced surface flow wetland. This is a surface flow wetland with deeper zones placed across its width at intervals. The deeper zones would be aerated with fine bubble diffuser systems. The aeration enhanced wetland to for this approach would have an area requirement of 29.5 acres and an energy demand of about 95,000 kW-hr per year. Aerated wetlands may have difficulty meeting the ammonia


August 2011


limit of 2.9 mg/L under winter conditions (2°C). The limit represents the know limit of wetland performance. Consequently there is very little data to support this design in light of regulatory review. Another approach to meet the ammonia discharge limit would be to use an aerated, gravel-bed or subsurface flow wetland to remove ammonia after the surface flow wetlands. This approach has the added advantage of producing low TSS and low turbidity allowing for smaller size or dosing of the subsequent disinfection system. The size and low construction cost of this approach are further advantages of this approach. One technology, known as a SAGR, was developed in Canada specifically to remove ammonia from lagoon effluents (down to water temperatures of 33°F) under very cold winter conditions in Manitoba, Saskatchewan, and Alberta. The SAGR unit would have an area of 0.5 acres and an energy demand of 78,500 kW-hr per year. Other technology options are possible and could be explored further in a more detailed analysis or preliminary engineering.

Third Stage-Polishing and Ammonia Removal with Aerated Gravel Bed

Energy for Aerated Gravel Bed Polishing: 78,500 kW-hr per year Approximate Land Requirement: 0.5 acres Discharge Standard 10 mg/L BOD5, 10 mg/L TSS, 2.9 mg/L NH3-N

4. Zero Discharge and/or Controlled Batch Discharge

With the climate in the Mabton area, it is apparent that a wetland will always “lose” water due to the water balance (P-E or ET). A basin designed to evaporate all of Mabton’s wastewater would require an area of approximately 120 acres. Zero discharge systems already exist. These systems are typically employed in very remote areas where an evaporation pond is not viewed as a nuisance and there is no chance of effluent re-use or discharge of the effluent to surface waters. This could be combined with a facultative lagoon (26 acres) for a zero-energy treatment alternative. If the evaporative basin had a watertight bottom and sides, it would eventually become a salt flat as dissolved solids in the effluent accumulated.

Zero Discharge

Energy for Facultative Lagoon Treatment: None Energy for Evaporation Basin: None Net Land Requirement: 146 acres Discharge Standard: No discharge and/or batch discharge

If the Department of Ecology has different discharge standards for intermittent discharges (Winter or Spring) during high flow periods in the Yakima River, small quantities of water could be released to prevent salt buildup in the wetland. This water would have relatively high total dissolved solids (TDS) due to concentration in the lagoon and wetlands. This alternative represents the most land-intensive option. It is also zero-energy for treatment and avoids most or all discharge requirements, because discharge to the Yakima River would be purely at the discretion of the City. A zero discharge system is not recommended for Mabton since maintaining discharge flows to the Yakima River is part of the current WWTF permit requirements.


August 2011


5. Nitrogen Removal

Nitrogen removal could be added to the alternatives outlined above. For initial nitrogen removal, effluent from the wetland or aerated gravel bed would be recycled back to the influent of the lagoon. Nitrate-nitrogen (oxidized ammonia) in the recycle would be consumed by bacteria metabolizing influent BOD. The combined effect of these processes is estimated to remove 80% of the total nitrogen (TN).

To ensure compliance with the 10 mg/L TN limit, a denitrification reactor could be added downstream of the aerated gravel bed reactor. This would be an un-aerated reactor with a BOD source such as ethanol or acetic acid added in controlled dosing. The bacteria films in the reactor consume the remaining nitrate while metabolizing the added BOD. A moving-bed bioreactor (MBBR) is an example of such a technology.

Denitrification – DN Recycle and MBBR Nutrient Removal Energy for Flow Recycling: 31,400 kW-hr per year Energy for MBBR Unit: 78,500 kW-hr per year Total Land Requirement: 0.2 acres

6. Phosphorous Removal

If required in future discharge permits, phosphorus removal can consistently be achieved with alum addition after the facultative lagoon. Phosphorus would precipitate in second lagoon with an area of approximately 2 acres. Accumulated sludge would be removed from this lagoon on a 5 year or longer basis depending on accumulation rates. This management approach could be added at a later date with minor modifications to the treatment process.

7. Sludge Management

Sludge will be generated in the lagoon from the removal of BOD and TSS. Sludge would also be generated from the phosphorus removal processes. This sludge can be dewatered on site in a reed bed for sludge dewatering. Solids from dewatered sludge are a very dry material similar to composted organic material, removed every 5 years and applied to land as a soil amendment. Alternatively, the sludge can be removed in a more liquid form directly from the lagoons and be applied to agricultural land. The latter approach provides a complete sludge management cost, and is listed in Table 17 below.

Sludge Source

Sludge Volume Generated Five Year Management Costs

Annual 5 year based on per gallon cost of:

gal/year Vol., gal. $0.04/gal $0.08/gal

Facultative or Partially Aerated Lagoon Total: Alternatives A-2

120,000 600,000 $24,000 $48,000

Phosphorus Removal Lagoon

180,000 900,000 $36,000 $72,000

Total for Alternative A-2 Plus Phosphorus Removal

300,000 500,000 $60,000 $120,000

Table 17. Sludge Management- Pump and Land Apply


August 2011


8. Temperature and Dissolved Oxygen

The dissolved oxygen concentration and water temperature are effluent parameters that may affect the design of the treatment system or timing of the effluent discharge. Effluent temperatures will be significantly affected by heat transfer in the lagoon and wetlands with seasonal variations. Limitations on increases in the river water temperature from effluent discharge may affect the system design and or timing of the discharge. Computer models need to be developed for effluent temperature and increases in river water temperature before further conclusions can be drawn. However, there are modifications to the lagoon design, such as floating vegetated rafts, which can be used to mitigate water temperature changes. One of the Department of Ecology criteria is that the alternative system be capable of achieving a dissolved oxygen (DO) level of 10 mg/L. If the site is flat, cascade aeration is not an option. In that case, a post-treatment aeration chamber would have to be provided to increase the effluent DO. The concentration of DO in the water decreases as the temperature increases. The target DO objective of 10 mg/L can only be met (through conventional aeration methods) when the water temperature is less than 59°F (American Fisheries Society, 1984). Analysis of the data in Figure 13 indicates that from June through September, the water would be too warm to sustain an equilibrium DO concentration above 10 mg/L. The DO concentration can be artificially increased using pure oxygen as a feedstock, but this would significantly add to the operational complexity of the system and may have an adverse impact to aquatic life in the Yakima River due to “fizzing” (spontaneous bubble formation in the effluent). It is recommended that the Washington Department of Ecology be contacted to confirm this standard before engineering controls are implemented to guarantee the 10 mg/L DO standard during the summer months.

9. Disinfection

All of the lagoon and wetland options summarized in this report create wildlife habitat for waterfowl, muskrats, and beavers. Wildlife use of the facility will add fecal coliform bacteria (non-human) to the effluent, so it is highly unlikely the facility could meet the proposed fecal coliform standard (100 per 100 mL) listed in Table 15, without a supplemental disinfection process (except for Scenario 1 – the zero discharge alternative). The disinfection process could be chlorine- or UV-based, but is considered outside of the scope of this evaluation. The use of a UV system is assumed for other references in this report as it is the current recommended method of disinfection listed in the proposed City of Mabton WWTF upgrade plans.


August 2011


10. Costs

Construction costs and operating energy demands of core components for the three main alternatives (A, B, and C) are summarized in Table 18. Construction cost estimates based on material quantities, component costs etc. are beyond the scope of this evaluation. Thus, construction cost estimates for the lagoon alternatives in based on cost curves presented in Technologies for Small Water and Wastewater Systems (Martin and Martin, 1991), and for the wetland options, Treatment Wetlands, Second Edition (Kadlec and Wallace, 2009). Construction costs were adjusted to an Engineering News Record (ENR) Construction Cost Index (CCI) of 8,310.

Table 18. Low Energy Treatment Alternative Summary

1. Primary screening, disinfection are required for complete treatment system. Sludge management is not included here. 2. Construction costs do not include land purchase, engineering, surveying, legal, or construction management. 3. Annual energy use based on estimated power required operating 24 hours/day, 365 days per year at annual flow of 240,000 gpd. 4. Aerated gravel bed or wetland for attached growth bacterial removal of ammonia to <2 mg/L 5. Moving Bed Bioreactor with carbon addition for final denitrification to <10 mg/L 6. Cost per kW-hr was obtained from Pacific Power & Light Company. 7. Estimates neglect all billing costs outside of energy useage.

Alternative Main Process Components1

Construction Costs2

Required land, acres

Energy Use kW-Hr/yr 3

Alternative A-1 Low-energy with ammonia removal

Facultative Lagoon SF Wetland + aeration AG Polishing Process4

$624,000 $432,000 $360,000

$1,416,000

26.0 6.0 0.5

32.5

0 62,800 62,800 125,600

Alternative A-2 Alternative A-1 + Nitrogen removal

Facultative Lagoon SF Wetland + aeration AG Polishing Process4 Recycle Pump Station MBBR –denitrfication5

$624,000 $432,000 $360,000 $65,000 $195,000

$1,676,000

26.0 6.0 0.5 0.1 0.1

32.7

0 62,800 62,800 31,400 31,400 188,400

Alternative B-1 Medium-energy + ammonia removal

Partial Aerated Lagoon SF Wetland + aeration AG Polishing Process4

$312,000 $446,400 $360,000

$1,184,000

4.0 6.0 0.5

10.5

300,000 62,800 62,800 425,600

Alternative B -2 Alternative B-1 + Nitrogen removal

Partial Aerated Lagoon SF Wetland + aeration AG Polishing Process4 Recycle Pump Station MBBR –denitrfication5

$312,000 $446,400 $360,000 $65,000 $195,000

$1,352,000

4.0 6.0 0.5 0.1 0.1

28.7

300,000 62,800 62,800 31,400 31,400 488,400

Alternative C Zero Discharge

Facultative Lagoon Evaporation Basin

$619,200 $3,312,000 $3,931,200

26.0 120.0 146.0

0 0 0


August 2011


E. Summary (Part 2: Energy Efficiency)

Alternative A-2 was selected as the favorite low energy wastewater treatment alternative because it provides reliable treatment in a moderate footprint with low capital costs and very low energy requirements. Alternative A can be easily upgraded for nutrient removal by adding additional low-energy, relatively low cost processes. Note that all the alternatives include a lagoon as the first biological treatment process. Lagoons are capable of absorbing peak flows and significant flow variation while discharging relatively stable outflows. This is an important consideration for Mabton, where peak daily flows are nearly three times the average annual flow.

Alternative A-2 - main components in approximate order (Figure 15-16): � Headworks screen � Facultative (non-aerated) lagoon – initial BOD and TSS removal � Surface flow wetland with aerated zones– additional BOD and TSS removal � Aerated gravel bed – treatment to meet discharge standards next permit cycle

(BOD<10 mg/L, TSS < 30 mg/L, Ammonia <2.9 mg/L) � UV System � Land Area- + 33.0 acres

The second favorite option is Alternative B-2 which also provides a cost-effective natural wastewater treatment system. This option may be considered as an alternative to A-2 since it requires less land area for its components.

Alternative B-2 - main components in approximate order (Figure 17): � Headworks screen � Partial Aerated Lagoon � Surface Flow (SF) Wetland + aeration Attached Growth (AG) Polishing Process � Recycle Pump Station � MBBR –denitrfication � UV System � Land Area- + 12.0 acres

Preliminary rough construction costs, land required and energy use for Alternative A-2 and Alternative B-2 are summarized in Table 19.


August 2011


Table 19. Selected Low Energy Treatment Alternatives

1. Primary screening, disinfection are required for complete treatment system. Sludge management is not included here.

2. Construction costs do not include land purchase, engineering, surveying, legal, or construction management.

3. Annual energy use based on estimated power required operating 24 hours/day, 365 days per year at annual flow of 240,000 gpd.

4. Aerated gravel bed or wetland for attached growth bacterial removal of ammonia to <2 mg/L.

5. Moving Bed Biofilm reactor with carbon addition for final denitrification to <10 mg/L.

6. Energy usages and costs from the current plant were averaged; this cost was applied to the Alternative A-2 and B-2 estimated annual energy requirement (~$0.06/kw-Hr).

7. Itemized list is available in City of Mabton Wastewater Facility Plan

Low Energy

Treatment AlternativeMain Process Components

1

Land

Requirement,

acres

Construction

Costs2

Estimated

Annual Energy

(kw-hrs/yr3)

Estimated

Annual Energy

Cost6 ($/yr)

· Facultative Lagoon $624,000 0· SF Wetland + aeration $432,000 62,800

· AG Polishing Process4 $360,000 62,800

· Recycle Pump Station $65,000 31,400

· MBBR-denitrification5 $195,000 31,400

Subtotal $1,676,000 188,400· Headworks $264,000 1,450· UV System $188,000 22,800· Land Cost ($4,500/acre) $148,500 0

Subtotal $600,500 24,250Total $2,276,500 212,650

· Partial Aerated Lagoon $312,000 300,000

· SF Wetland + aeration $446,400 62,800

· AG Polishing Process4 $360,000 62,800

· Recycle Pump Station $65,000 31,400· MBBR –denitrfication

5$195,000 31,400

Subtotal $1,378,400 488,400

· Headworks $264,000 1,450

· UV System $188,000 22,800

· Land Cost ($4,500/acre) $54,000 0

Subtotal $506,000 24,250

Total $1,884,400 512,650

Existing WWTF · Oxidation Ditch 647,880 $18,000

· New Aerobic Basin

and Oxidation Ditch$5,410,000 842,244

Total - $5,410,000 842,244

33

Alternative A-2

(Alternative A-1 +

ammonia removal)

$24,000Aeration Alternative 37

Alternative B-2

(Alternative B-1 +

nitrogen removal)

12 $31,722

$13,160


August 2011


Figure 16. Alternative A-2 Process Diagram


August 2011


Figure 17. Alternative A-2 Site Plan


August 2011


Figure 18. Alternative A-2 Process Diagram


August 2011


F. References (Part 2)

Colt, J., 1984. Computation of Dissolved Gas Concentrations in Water as Functions of

Temperature, Salinity, and Pressure. American Fisheries Society Special Publication 14.

Davis, California.

Crites, R.W., Middlebrooks, E.J., Reed S.C., 2006. Natural Wastewater Treatment Systems.

Boca Raton, Florida. CRC Press.

Kadlec, R.H., 2004. Wetland to Pond Treatment Gradients. Proceedings of the 9th International

Conference on Wetland Systems; Avignon, France. 26 September – 1 October, 2004.

International Water Association.

Kadlec, R.H., Wallace, S.D., 2009. Treatment Wetlands, Second Edition. Boca Raton, Florida.

CRC Press.

Martin, E.J., Martin E.T., 1991. Technologies for Small Water and Wastewater Systems. New

York, New York. Van Nostrand Reinhold.

Rich, L.R., 1999. High Performance Aerated Lagoon Systems. American Academy of

Environmental Engineers.