water and wastewater infrastructure spellman

6000 Broken Sound Parkway, NW Suite 300, Boca Raton, FL 33487711 Third Avenue New York, NY 100172 Park Square, Milton Park Abingdon, Oxon OX14 4RN, UK

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K15133

ENVIRONMENTAL ENGINEERING

Energy Efficiency and Sustainability

Frank R. Spellman

WATER & WASTEWATERINFRASTRUCTUREEnergy Efficiency and Sustainability

WATER &

WASTEW

ATER INFRASTRUCTURE

Spellman

WATER & WASTEWATER

INFRASTRUCTURE

WATER & WASTEWATER

INFRASTRUCTURE

A critical aspect of sustainability associated with water and wastewater systems is to maintain and manage infrastructure in the most efficient and economical manner while complying with environmental regulations and keeping rates at acceptable levels. Given the high cost of fuel, our growing population, and the associated increase in energy needs, it is important to address energy use and future energy availability for the treatment of the water we drink and the water we pollute. Water & Wastewater Infrastructure: Energy Efficiency and Sustainability addresses these issues, detailing the processes that can assist facilities to become more energy efficient and providing guidance to ensure their sustainability. The text begins with brief descriptions of the water and wastewater treatment industries. It then describes some of the basics of energy and discusses what planning for a sustainable energy future in water and wastewater treatment plants entails. The author explores energy-saving options and provides case studies to demonstrate how some facilities have used equipment, technology, and operating strategies to save money and reduce their impact. The energy-efficient technologies include combined heat and power (CHP), gas turbines, microturbines, reciprocating engines, steam turbines, and fuel cells. The author also addresses biomass power and biogas. The section on sustainability and renewable energy covers hydropower, solar power, and wind power as well as energy conservation measures for treating wastewater. Nine appendices provide individual case studies that present evaluations of energy conservation measures, results, payback analysis, and conclusions. This book addresses the challenges faced by water and wastewater treatment facilities by examining how they can operate in ways that provide economic and environmental benefits, save money, reduce environmental impact, and lead to sustainability.

K15133_cover.indd 1 1/18/13 11:43 AM

Boca Raton London New York

CRC Press is an imprint of theTaylor & Francis Group, an informa business

Energy Effi ciency and Sustainability

WATER& WASTEWATER

INFRASTRUCTURE

Frank R. Spellman

CRC PressTaylor & Francis Group6000 Broken Sound Parkway NW, Suite 300Boca Raton, FL 33487-2742

2013 by Taylor & Francis Group, LLCCRC Press is an imprint of Taylor & Francis Group, an Informa business

No claim to original U.S. Government worksVersion Date: 20121106

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For

Melissa L. Stoudt

vContents

Preface ........................................................................................................................................... xiiiAuthor .............................................................................................................................................xvAcronyms and Abbreviations .................................................................................................. xvii

Section I The Basics

1. Introduction .............................................................................................................................31.1 Setting the Stage ............................................................................................................31.2 Sustainable Water/Wastewater Infrastructure .........................................................5

1.2.1 Maintaining Sustainable Infrastructure.......................................................51.2.2 Cash Cows or Cash Dogs? ..............................................................................7

1.3 Water/Wastewater Infrastructure Gap ......................................................................81.4 Energy Efficiency: Water/Wastewater Treatment Operations ...............................9References and Recommended Reading ..............................................................................9

2. Characteristics of the Wastewater and Drinking Water Industries ........................... 112.1 Introduction ................................................................................................................. 12

2.1.1 Wastewater and Drinking Water Terminology ......................................... 122.2 Characteristics of the Wastewater Industry ............................................................22

2.2.1 Wastewater Treatment Process: The Model ...............................................222.3 Characteristics of the Drinking Water Industry .....................................................232.4 Capital Stock and Impact on Operations and Maintenance ................................. 24

2.4.1 Useful Life of Assets ...................................................................................... 242.4.2 Operating and Maintaining Capital Stock ................................................. 26

2.5 Wastewater Capital Stock........................................................................................... 272.6 Drinking Water Capital Stock ...................................................................................282.7 Costs of Providing Service ......................................................................................... 29References and Recommended Reading ............................................................................30

3. Water, Wastewater, and Energy ......................................................................................... 313.1 Introduction ................................................................................................................. 313.2 Energy Basics ............................................................................................................... 31

3.2.1 Potential Energy ............................................................................................. 323.2.2 Kinetic Energy ................................................................................................33

3.3 Renewable and Nonrenewable Energy ....................................................................343.3.1 Mix of Energy Production Changes ............................................................35

3.4 Units for Comparing Energy .....................................................................................35References and Recommended Reading ............................................................................36

4. Planning for a Sustainable Energy Future ...................................................................... 374.1 Wastewater and Drinking Water Treatment Energy Usage ................................. 37

4.1.1 Current and Future Challenges ................................................................... 37

vi Contents

4.2 Fast Facts ......................................................................................................................384.3 Benchmark It! ............................................................................................................... 39

4.3.1 What Benchmarking Is .................................................................................404.3.2 Potential Results of Benchmarking ............................................................. 414.3.3 Targets ............................................................................................................. 414.3.4 Process of Benchmarking ............................................................................. 414.3.5 Benchmarking Steps ...................................................................................... 414.3.6 Collection of Baseline Data and Tracking Energy Use .............................42

4.4 Baseline Audit .............................................................................................................464.4.1 Field Investigation.......................................................................................... 474.4.2 Create Equipment Inventory and Distribution of Demand and Energy ................................................................................. 47

References and Recommended Reading ............................................................................50

Section II Energy-Efficient Equipment, Technology, and Operating Strategies

5. Energy-Efficient Equipment ...............................................................................................535.1 Introduction .................................................................................................................535.2 Motors ...........................................................................................................................53

5.2.1 AC Motors .......................................................................................................535.2.2 Electric Motor Load and Efficiency ............................................................. 575.2.3 Determining Motor Loads ............................................................................ 595.2.4 Determining Motor Efficiency .....................................................................63

5.3 Variable-Frequency Drives ........................................................................................655.4 HVAC Enhancements ................................................................................................. 675.5 Energy-Smart Lighting ...............................................................................................68References and Recommended Reading ............................................................................72

6. Energy-Efficient Operating Strategies ............................................................................. 736.1 Introduction ................................................................................................................. 736.2 Electrical Load Management ..................................................................................... 73

6.2.1 Rate Schedules ................................................................................................ 736.2.2 Energy Demand Management ..................................................................... 746.2.3 Electrical Load Management Success Stories ............................................ 75

6.3 Biosolids Management ............................................................................................... 786.3.1 Biosolids: Background Information ............................................................ 796.3.2 Sources of Biosolids ....................................................................................... 796.3.3 Biosolids Characteristics ...............................................................................80

6.4 Operations and Maintenance: Energy- and Cost-Saving Procedures ................. 816.4.1 Chandler Municipal Utilities, Arizona ....................................................... 826.4.2 Airport Water Reclamation Facility, Prescott, Arizona ............................836.4.3 Somerton Municipal Water, Arizona ..........................................................846.4.4 Hawaii County Department of Water Supply ...........................................856.4.5 Eastern Municipal Water District, California ............................................ 876.4.6 Port Drive Water Treatment Plant, Lake Havasu, Arizona ......................886.4.7 Truckee Meadows Water Authority, Reno, Nevada .................................. 89

viiContents

6.4.8 Tucson Water, Arizona .................................................................................. 916.4.9 PrescottChino Water Production Facility, Prescott, Arizona ................ 936.4.10 Somerton Municipal Wastewater Treatment Plant, Arizona................... 94

6.5 Inflow and Infiltration Control ................................................................................. 956.5.1 Combined Sewer Systems ............................................................................. 956.5.2 Basement Sump Pump Redirection ............................................................ 97

References and Recommended Reading .......................................................................... 101

Section III Energy-Efficient Technology

7. Combined Heat and Power (CHP) ................................................................................... 1057.1 Introduction ............................................................................................................... 1057.2 CHP Key Definitions ................................................................................................ 1067.3 Calculating Total CHP System Efficiency ............................................................. 1077.4 Calculating Effective Electric Efficiency ................................................................ 1087.5 Selecting CHP Efficiency Metrics ........................................................................... 1097.6 Wastewater Treatment Facilities with CHP .......................................................... 1097.7 Overview of CHP Technologies .............................................................................. 111References and Recommended Reading .......................................................................... 111

8. Gas Turbines ........................................................................................................................ 1138.1 Introduction ............................................................................................................... 1138.2 Applications ............................................................................................................... 1148.3 Gas Turbine Technology .......................................................................................... 115

8.3.1 Modes of Operation ..................................................................................... 1168.3.2 Design Characteristics ................................................................................ 1168.3.3 Performance Characteristics ...................................................................... 1178.3.4 Emissions ...................................................................................................... 121


9. Microturbines ...................................................................................................................... 1239.1 Introduction ............................................................................................................... 1239.2 Microturbine Applications ...................................................................................... 1239.3 Microturbine Technology ........................................................................................ 124

9.3.1 Basic Components ........................................................................................ 1259.3.2 CHP Operation ............................................................................................. 127

9.4 Design Characteristics .............................................................................................. 1289.5 Microturbine Performance Characteristics ........................................................... 128

9.5.1 Effects of Ambient Conditions on Performance ...................................... 1299.5.2 Heat Recovery............................................................................................... 1299.5.3 Performance and Efficiency Enhancements ............................................ 1299.5.4 Maintenance ................................................................................................. 1319.5.5 Fuels ............................................................................................................... 1329.5.6 Availability.................................................................................................... 1329.5.7 Disadvantages .............................................................................................. 132

9.6 Emissions ................................................................................................................... 132References and Recommended Reading .......................................................................... 133

viii Contents

10. Reciprocating Engines ....................................................................................................... 13510.1 Introduction ............................................................................................................... 13510.2 Applications ............................................................................................................... 136

10.2.1 Combined Heat and Power ........................................................................ 13710.3 Reciprocating Engine Technology .......................................................................... 13810.4 Design Characteristics .............................................................................................. 13910.5 Performance Characteristics .................................................................................... 140

10.5.1 Electrical Efficiency ..................................................................................... 14010.5.2 Load Performance ........................................................................................ 14010.5.3 Heat Recovery............................................................................................... 14010.5.4 Performance and Efficiency Enhancements ............................................ 14210.5.5 Maintenance ................................................................................................. 14310.5.6 Fuels ............................................................................................................... 143

10.6 Emissions ................................................................................................................... 14510.6.1 Nitrogen Oxides (NOx) ................................................................................ 14610.6.2 Carbon Monoxide ........................................................................................ 14610.6.3 Unburned Hydrocarbons ........................................................................... 14610.6.4 Carbon Dioxide ............................................................................................ 147


11. Steam Turbines ................................................................................................................... 14911.1 Introduction ............................................................................................................... 14911.2 Applications ............................................................................................................... 150

11.2.1 Industrial and CHP Applications .............................................................. 15011.2.2 Combined-Cycle Power Plants ................................................................... 151

11.3 Steam Turbine: Basic Process and Components ................................................... 15111.3.1 Boilers ............................................................................................................ 15311.3.2 Types of Steam Turbines ............................................................................. 15311.3.3 Design Characteristics ................................................................................ 154

11.4 Performance Characteristics .................................................................................... 15511.4.1 Electrical Efficiency ..................................................................................... 15511.4.2 Operating Characteristics ........................................................................... 15511.4.3 Process Steam and Performance Trade-Offs ............................................ 15611.4.4 CHP System Efficiency ................................................................................ 15611.4.5 Performance and Efficiency Enhancements ............................................ 15611.4.6 Steam Reheat ................................................................................................ 15711.4.7 Combustion Air Preheating ....................................................................... 15711.4.8 Maintenance ................................................................................................. 15711.4.9 Fuels ............................................................................................................... 15811.4.10 Availability.................................................................................................... 158

11.5 Emissions ................................................................................................................... 158References and Recommended Reading .......................................................................... 158

12. Fuel Cells .............................................................................................................................. 16112.1 Introduction ............................................................................................................... 16112.2 Fuel Cells: The Basics ................................................................................................ 162

12.2.1 Open Cells vs. Closed Cells ........................................................................ 16212.3 Hydrogen Fuel Cells: A Realistic View .................................................................. 164

ixContents

12.3.1 Hydrogen Storage ........................................................................................ 16512.3.2 How a Hydrogen Fuel Cell Works ............................................................ 165

12.4 CHP Applications ..................................................................................................... 166References and Recommended Reading .......................................................................... 167

Section IV Biomass Power and Heat Generation

13. CHP and Wastewater Biogas ............................................................................................ 17113.1 Grasshopper Generation .......................................................................................... 17113.2 Biomass ....................................................................................................................... 173

13.2.1 Feedstock Types............................................................................................. 173 13.2.2 Composition of Biomass .............................................................................. 174

13.3 Biomass for Power and Heat Generation ............................................................... 17513.4 Biogas (Methane, CH4).............................................................................................. 176

13.4.1 The 411 on Methane ..................................................................................... 17713.5 Wastewater Treatment Plant Biogas ....................................................................... 178

13.5.1 Anaerobic Digestion .................................................................................... 17913.6 Cogeneration Using Landfill Biogas ...................................................................... 18213.7 Biodiesel ..................................................................................................................... 183References and Recommended Reading .......................................................................... 186

Section V Sustainability Using Renewable Energy

14. Macro- and Microhydropower ......................................................................................... 19314.1 Introduction ............................................................................................................... 19314.2 Hydropower ............................................................................................................... 193

14.2.1 Impoundment ............................................................................................... 19514.2.2 Diversion ....................................................................................................... 19614.2.3 Pumped Storage ........................................................................................... 196

14.3 Hydropower Basic Concepts ................................................................................... 19614.3.1 Stevins Law .................................................................................................. 19714.3.2 Density and Specific Gravity ...................................................................... 19814.3.3 Force and Pressure .......................................................................................20014.3.4 Hydrostatic Pressure ................................................................................... 20114.3.5 Head ............................................................................................................... 20214.3.6 Flow and Discharge Rates: Water in Motion ........................................... 20414.3.7 Area and Velocity ........................................................................................ 20514.3.8 Pressure and Velocity .................................................................................. 20614.3.9 Conservation of Energy .............................................................................. 20614.3.10 Energy Head ................................................................................................. 20614.3.11 Energy Available .......................................................................................... 20614.3.12 Major Head Loss .......................................................................................... 20614.3.13 Minor Head Loss.......................................................................................... 209

14.4 Reservoir Stored Energy .......................................................................................... 20914.5 Hydroturbines ........................................................................................................... 211

14.5.1 Impulse Turbine ........................................................................................... 21114.5.2 Reaction Turbine .......................................................................................... 211

14.6 Advanced Hydropower Technology ...................................................................... 211

x Contents

14.7 Hydropower Generation: Dissolved Oxygen Concerns ...................................... 21214.8 Bottom Line on Macrohydropower ........................................................................ 21314.9 Microhydropower Concepts .................................................................................... 214

14.9.1 Microhydropower Key Terms .................................................................... 21414.9.2 Potential Microhydropower Sites .............................................................. 21614.9.3 Head at Potential Microhydropower Site ................................................. 21714.9.4 Flow at Potential Microhydropower Site .................................................. 21814.9.5 Economics ..................................................................................................... 220

14.10 Permits and Water Rights ........................................................................................ 220References and Recommended Reading .......................................................................... 220

15. Solar Power ..........................................................................................................................22315.1 Introduction ...............................................................................................................22315.2 Concentrating Solar Power ......................................................................................225

15.2.1 Linear Concentrators ...................................................................................22515.2.2 Dish/Engine Systems ..................................................................................22615.2.3 Power Tower System ....................................................................................22715.2.4 Thermal Energy Storage .............................................................................228

15.3 Photovoltaics (PV) ..................................................................................................... 23115.4 Solar Power Applications ......................................................................................... 232

15.4.1 Solar Hot Water ............................................................................................23315.4.2 Solar Process Heat .......................................................................................234

15.5 Structure Daylighting ...............................................................................................23615.5.1 Daylight Zone ...............................................................................................23615.5.2 Window Design Considerations ................................................................ 23715.5.3 Effective Aperture (EA) ..............................................................................23815.5.4 Light Shelves .................................................................................................23815.5.5 Toplighting Strategies .................................................................................238

15.6 Water and Wastewater Treatment Plant Applications ......................................... 239References and Recommended Reading .......................................................................... 240

16. Wind Power .......................................................................................................................... 24516.1 Introduction ............................................................................................................... 24516.2 Its All about the Wind ............................................................................................. 24616.3 Air in Motion ............................................................................................................. 24716.4 Wind Energy ..............................................................................................................25016.5 Wind Power Basics .................................................................................................... 25216.6 Wind Turbine Types ................................................................................................. 252

16.6.1 Horizontal-Axis Wind Turbines ................................................................25316.7 Turbine Features ........................................................................................................25316.8 Wind Energy and Power Calculations ................................................................... 255

16.8.1 Air-Density Correction Factors .................................................................. 25716.8.2 Elevation and Earths Roughness .............................................................. 25716.8.3 Wind Turbine Rotor Efficiency .................................................................. 25816.8.4 Derivation of Betzs Law ............................................................................. 25816.8.5 Tip Speed Ratio (TSR) .................................................................................. 260

16.9 Small-Scale Wind Power .......................................................................................... 26216.10 Wind Power Applications in Water/Wastewater Treatment .............................. 266References and Recommended Reading .......................................................................... 267

xiContents

17. Energy Conservation Measures for Wastewater Treatment ...................................... 26917.1 Introduction ............................................................................................................... 26917.2 Pumping System Energy Conservation Measures ............................................... 270

17.2.1 Pumping System Design ............................................................................. 27117.2.2 Pump Motors ................................................................................................ 27217.2.3 Power Factor .................................................................................................27717.2.4 Variable-Frequency Drives .........................................................................280

17.3 Design and Control of Aeration Systems .............................................................. 28117.3.1 ECMs for Aeration Systems ........................................................................ 28217.3.2 Control of the Aeration Process ................................................................. 28617.3.3 Innovative and Emerging Control Strategies for Biological Nitrogen Removal ............................................................... 294

17.4 Blowers ....................................................................................................................... 29617.4.1 High-Speed Gearless (Turbo) Blowers ...................................................... 29917.4.2 Single-Stage Centrifugal Blowers with Inlet Guide Vanes and Variable Diffuser Vanes ...................................... 29917.4.3 New Diffuser Technology ..........................................................................30017.4.4 Preventing Diffuser Fouling ...................................................................... 30117.4.5 Innovative and Emerging Energy Conservation Measures .................. 30117.4.6 UV Disinfection ...........................................................................................30217.4.7 Membrane Bioreactors ................................................................................30617.4.8 Anoxic and Anaerobic Zone Mixing......................................................... 307


Section VI Appendices

Appendix A. Magnetic Bearing Turbo Blowers at the Green Bay Metropolitan Sewerage District De Pere Wastewater Treatment Facility ........................................ 317

Appendix B. Turblex Blowers and Air Flow Control Valves on the Sheboygan Regional Wastewater Treatment Plant ......................................... 325

Appendix C. Upgrade from Mechanical Aeration to Air-BearingTurbo Blowers and Fine-Bubble Diffusers at the Big GulchWastewater Treatment Plant .............................................................................................333

Appendix D. Optical DO Sensor Technology and Aerator Rotor VFD Control at the City of Bartlett, Tennessee, Wastewater Treatment Plant ...............................343

Appendix E. Advanced Aeration Control for the Oxnard, California, Wastewater Treatment Plant .......................................................349

Appendix F. DO Optimization Using Floating Pressure Blower Control in a Most Open Valve Strategy at the Narragansett Bay Commission Bucklin Point WTTP, Rhode Island ...................... 359

Appendix G. Capacity and Fuel Efficiency Improvements at Washington Suburban Sanitary Commission Western Branch WWTP, Prince Georges County, Maryland .................................................... 369

xii Contents

Appendix H. Permit-Safe and Energy-Smart Greening of Wastewater Treatment Plant Operations at the San Jose/Santa Clara, California, Water Pollution Control Plant ..................................................................... 379

Appendix I. Diffuser Upgrades and DO Controlled Blowers at the Waco, Texas, Metropolitan Area Regional Sewer System Wastewater Treatment Facility ......... 389

Glossary ....................................................................................................................................... 397

Index ............................................................................................................................................. 431

xiii

Preface

At its core, this book is about facing realitya pressing reality. That is, this book is about energy use today and future energy availability for the treatment of the water we drink and the water we foul through our use or abuse (or both). The pressing reality? Have you noticed the current prices of gasoline, heating oil, and diesel fuel in the United States? The pressing reality of the high cost of hydrocarbon fuels is just one facet of the growing problem. How about our growing population and the corresponding need to increase our use of energy to support, maintain, and sustain the growing population? Moreover, we also need to consider worldwide growth in energy needs, now and in the future. China and India, for example, are expanding their populations, their economies, and thus their need for energy.

With regard to the focus of Water & Wastewater Infrastructure: Energy Efficiency and Sustainability, keep in mind that water and wastewater treatment facilities across the country are facing many common challenges, including rising costs, aging infrastructure, increasingly stringent regulatory requirements, population changes, and a rapidly chang-ing workforce. Accordingly, to address these issues and to focus managerial energy toward mitigating these issues, water and wastewater facilities must strive to operate in a manner that provides economic and environmental benefits, saves money, reduces environmental impacts, and leads to sustainability. This can best be accomplished by improving energy efficiency and water efficiency.

The bottom line: This book not only details processes that can assist facilities to become more energy efficient but also provides guidance to ensure their operational sustainability.

xv

Author

Frank R. Spellman, PhD, is a retired U.S. naval officer with 26 years of active duty, a retired envi-ronmental safety and health manager for a large wastewater sanitation district in Virginia, and a retired assistant professor of environmental health at Old Dominion University, Norfolk, Virginia. He is the author or co-author of 75 books, with more soon to be published. Dr. Spellman consults on environ-mental matters with the U.S. Department of Justice and various law firms and environmental entities around the globe. He holds a BA in public admin-istration, a BS in business management, and a MBA, MS, and PhD in environmental engineering. In 2011, he traced and documented the ancient water distri-

bution system at Machu Pichu, Peru, and surveyed several drinking water resources in Amazonia, Ecuador. Dr. Spellman also studied and surveyed two separate potable water supplies in the Galapagos Islands.

xvii

Acronyms and Abbreviations

C Degrees Centigrade or CelsiusF Degrees Fahrenheit Microng Microgramm MicrometerA/O Anoxic/oxicA2/O Anaerobic/anaerobic/oxicAC Alternating currentACEEE American Council for an Energy Efficient EconomyAl3 Aluminum sulfate (or alum)Amp AmperesAnammox Anaerobic ammonia oxidationAPPA American Public Power AssociationAS Activated sludgeASCE American Society of Civil EngineersASE Alliance to Save EnergyATM AtmosphereAWWA American Water Works AssociationBABE Bio-augmentation batch enhancedBAF Biological aerated filterBAR Bioaugmentation reaerationBASIN Biofilm activated sludge innovative nitrificationBEP Best efficiency pointbhp Brake horsepowerBNR Biological nutrient removalBOD Biochemical oxygen demandBOD-to-TKN Biochemical oxygen demand-to-total Kjeldahl nitrogen ratioBOD-to-TP Biochemical oxygen demand-to-total phosphorus ratioBPR Biological phosphorus removalCANON Completely autotrophic nitrogen removal over nitrateCAS Cyclic activated sludgeCBOD Carbonaceous biochemical oxygen demandCCCSD Central Contra Costa Sanitary DistrictCEC California Energy CommissionCEE Consortium for Energy Efficiencycfm Cubic feet per minuteCFO Cost flow opportunitycfs Cubic feet per secondCHP Combined heat and powerCi CurieCOD Chemical oxygen demandCP Central plantCV Coefficient of variationCWSRF Clean Water State Revolving Fund

xviii Acronyms and Abbreviations

DAF Dissolved-air flotation unitDCS Distributed control systemDO Dissolved oxygenDOE Department of EnergyDON Dissolved organic nitrogenDSIRE Database of State Incentives for Renewables and EfficiencyEBPR Enhanced biological phosphorus removalECM Energy conservation measureENR Enhanced nitrogen removalEPA Environmental Protection AgencyEPACT Energy Policy ActEPC Energy performance contractingEPRI Electric Power Research InstituteESCO Energy Services CompanyFeCl3 Ferric chlorideFFS Fixed-film systemGAO Glycogen accumulating organismGBMSD Green Bay, WI, Metropolitan Sewerage DistrictGPD Gallons per dayGPM Gallons per minuteH2CO3 Carbonic acidHCO3 BicarbonateHDWK Headworkshp HorsepowerHRT Hydraulic retention timeHz HertzI&C Instrumentation and controlI&I Inflow and infiltrationIFAS Integrated fixed-film activated sludgeIOA International Ozone AssociationIUVA International Ultraviolet AssociationkW Kilowatt hourkWh/year Kilowatt-hours per yearLPHO Low-pressure, high-outputM MegaM MillionMBR Membrane bioreactorMG Million gallonsmg/L Milligrams per liter (equivalent to parts per million)MGD Million gallons per dayMLE Modified LudzackEttinger processMLSS Mixed liquor suspended solidsMPN Most probable numberMW Molecular weightN NitrogenNAESCO National Association of Energy Service CompaniesNEMA National Electrical Manufacturers AssociationNH4 AmmoniumNH4N Ammonia nitrogen

xixAcronyms and Abbreviations

NL No limitNPDES National Pollutant Discharge Elimination SystemNYSERDA New York State Energy Research and Development AuthorityO&M Operation and maintenanceORP Oxidationreduction potentialPa PascalPAO Phosphate accumulating organismsPG&E Pacific Gas and ElectricPID Phased isolation ditchPLC Programmable logic controllerPO4

3 PhosphatePOTWs Publicly owned treatment worksPSAT Pump system assessment toolpsi Pounds per square inchpsig Pounds per square inch gaugeRAS Return activated sludgerpm Revolutions per minuteSBR Sequencing batch reactorSCADA Supervisory control and data acquisitionscfm Standard cubic feet per minuteSRT Solids retention timeTDH Total dynamic headTKL Total Kjeldahl nitrogenTMDL Total maximum daily loadTN Total nitrogenTP Total phosphorusTSS Total suspended solidsTVA Tennessee Valley AuthorityUV Ultraviolet lightUVT UV transmittanceVFD Variable-frequency driveVSS Volatile suspended solidsW WattWAS Waste activated sludgeWEF Water Environment FederationWEFTEC Water Environment Federation Technical Exhibition & ConferenceWERF Water Environment Research FoundationWMARSS Waco Metropolitan Area Regional Sewer SystemWPCP Water Pollution Control PlantWRF Water Research FoundationWSU Washington State UniversityWWTP Wastewater treatment plant

Section I

The Basics

31Introduction

The US economy, because its so energy wasteful, is much less efficient than either the European or Japanese economies. It takes us twice as much energy to produce a unit of GDP as it does in Europe and Japan. So, were fundamentally less efficient and therefore less competitive, and the sooner we begin to tighten up, the better it will be for our economy and society.

Hazel Henderson (on ENN Radio)

1.1 Setting the Stage

Several long-term economic, social, and environmental trendsthe so-called triple bot-tom line (Elkington, 1999)are evolving around us. Many of these long-term trends are developing because of us and specifically for us or simply to sustain us. Many of these long-term trends follow general courses and can be described by the jargon of the day; that is, they can be alluded to or specified by specific buzzwords commonly used today. We frequently hear these buzzwords used in general conversation (especially in abbreviated texting form). Buzzwords such as empowerment, outside the box, streamline, wellness, synergy, generation X, face time, exit strategy, clear goal, and so on and so forth are just part of our daily vernacular.

In this book, the popular buzzword we are concerned with, sustainability, is often used in business. In water and wastewater treatment, however, sustainability is much more than just a buzzword; it is a way of life (or should be). Many of the numerous definitions of sus-tainability are overwhelming, vague, or indistinct. For our purposes, there is a long defi-nition and short definition of sustainability. The long definition is ensuring that water and wastewater treatment operations occur indefinitely without negative impact. The short definition is the capacity of water and wastewater operations to endure. Whether we define long or short fashion, what does sustainability really mean in the real world of water and wastewater treatment operations?

We have defined sustainability in both long and short form. Note, however, that sustain-ability in water and wastewater treatment operations can be characterized in broader or all-encompassing terms than these simple definitions. We can use the triple bottom line scenario, with regard to sustainability, the environmental aspects, economic aspects, and social aspects of water and wastewater treatment operations, to define todays and tomor-rows needs more specifically.

Infrastructure is another term used in this text; it can be used to describe water and waste-water operation in the whole, or it can identify several individual or separate elements of water and wastewater treatment operations. In wastewater operations, for example, we

4 Water & Wastewater Infrastructure: Energy Efficiency and Sustainability

can focus extensively on wastewater collection and interceptor systems, lift or pumping stations, influent screening, grit removal, primary clarification, aeration, secondary clarifi-cation, disinfection, outfalling, and a wide range of solids handling unit processes. On an individual basis, each of these unit processes can be described as an integral infrastruc-ture component of the process. Or, holistically, we simply could group each unit process as one, as a whole, combining all wastewater treatment plant unit processes as the opera-tional infrastructure. We could do the same for water treatment operations; for example, for individual water treatment infrastructure components, fundamental systems, or unit processes, we could list source water intake, pretreatment, screening, coagulation and mixing, flocculation, settling and biosolids processing, filtering, disinfection, and stor-age and distribution systems. Otherwise, we could simply describe water treatment plant operations as the infrastructure.

How one chooses to define infrastructure is not important. What is important is to main-tain and manage infrastructure in the most efficient and economical manner possible to ensure its sustainability. This is no easy task. Consider, for example, the 2009 Report Card for American Infrastructure produced by the American Society of Civil Engineers, shown in Table 1.1.

Not only must water and wastewater treatment managers maintain and operate aging and often underfunded infrastructure, but they must also comply with stringent environ-mental regulations and must keep stakeholders and ratepayers satisfied with operations and with rates. Moreover, in line with these considerations, managers must incorporate economic considerations into every decision; for example, they must meet regulatory standards for quality of treated drinking water and outfalled wastewater effluent. They must also plan for future upgrades or retrofits that will enable the water or wastewater facility to meet future water quality and future effluent regulatory standards. Finally, and most importantly, managers must optimize the use of manpower, chemicals, and electricity.

Table 1.1

2009 Report Card for American Infrastructure

Infrastructure Grade

Bridges CDams DDrinking water DEnergy D+Hazardous waste DRail CRoads DSchools DWastewater D

Americas infrastructure GPA: D

Source: Adapted from ASCE, 2009 Report Card for Americas Infrastructure, American Society of Civil Engineers, Reston, VA, 2009 (http://www.infrastructure reportcard. org/report-cards).

5Introduction

1.2 Sustainable Water/Wastewater Infrastructure

The U.S. Environmental Protection Agency (USEPA, 2012) has defined sustainable develop-ment as that which meets the needs of the present generation without compromising the ability of future generations to meet their needs. The current U.S. population benefits from the investments that were made over the past several decades to build our nations water/wastewater infrastructure.

Practices that encourage water and wastewater sector utilities and their customers to address existing needs so that future generations will not be left to address the approach-ing wave of needs resulting from aging water and wastewater infrastructure must con-tinuously be promoted by sector professionals. To be on a sustainable path, investments need to result in efficient infrastructure and infrastructure systems and be at a pace and level that allow the water and wastewater sectors to provide the desired levels of service over the long term.

Sounds easy enough: The water/wastewater manager simply needs to put his or her operation on a sustainable path; moreover, he or she can simply accomplish this by invest-ing. Right? Well, investing what? Investing in what? Investing how much? These are questions that require answers, obviously. Before moving on with this discussion it is important first to discuss plant infrastructure basics (focusing primarily on wastewater infrastructure and in particular on piping systems) and then to discuss funding (the cash cow vs. cash dog syndrome).

1.2.1 Maintaining Sustainable Infrastructure

During the 1950s and 1960s, the U.S. government encouraged the prevention of pollution by providing funds for the construction of municipal wastewater treatment plants, water pollution research, and technical training and assistance. New processes were developed to treat sewage, analyze wastewater, and evaluate the effects of pollution on the environ-ment. In spite of these efforts, however, the expanding population and industrial and eco-nomic growth caused pollution and health issues to increase.

In response to the need to make a coordinated effort to protect the environment, the National Environmental Policy Act (NEPA) was signed into law on January 1, 1970. In December of that year, a new independent body, the USEPA, was created to bring under one roof all of the pollution control programs related to air, water, and solid wastes. In 1972, the Water Pollution Control Act Amendments expanded the role of the federal gov-ernment in water pollution control and significantly increased federal funding for con-struction of wastewater treatment plants.

DID YOU KNOW?

Looking at water distribution piping only, the USEPAs 2000 survey on community water systems found that in systems that serve more than 100,000 people, about 40% of drinking water pipes were greater than 40 years old. It is important to remember, though, that age, in and of itself, does not necessarily indicate problems. If a system is well maintained, it can operate over a long time period (USEPA, 2012).


Many of the wastewater treatment plants in operation today are the result of federal grants made over the years; for example, the 1977 Clean Water Act Amendment to the Federal Water Pollution Control Act of 1972 and the 1987 Clean Water Act reauthorization bill provided funding for wastewater treatment plants. Many large sanitation districts, with their multiple plant operations, and even a larger number of single plant operations in smaller communities in operation today, are a result of these early environmental laws. Because of these laws, the federal government provided grants of several hundred million dollars to finance construction of wastewater treatment facilities throughout the country.

Many of these locally or federally funded treatment plants are aging; based on experi-ence, we can rate some as dinosaurs. The point is that many facilities are facing prob-lems caused by aging equipment, facilities, and infrastructure. Complicating the problems associated with natural aging is the increasing pressure on inadequate older systems to meet demands of increased population and urban growth. Facilities built in the 1960s and 1970s are now 40 to over 50 years old, and not only are they showing signs of wear and tear but they also simply were not designed to handle the level of growth that has occurred in many municipalities.

Regulations often necessitate a need to upgrade. By receiving matching funds or oth-erwise being provided federal money to cover some of the costs, municipalities can take advantage of a window of opportunity to improve their facilities at a lower direct cost to their communities. Those federal dollars, of course, do come with strings attached, as they are to be spent on specific projects in specific areas. On the other hand, many times new regulatory requirements are put in place without the financial assistance needed to imple-ment them. When this occurs, either the local community ignores the new requirements (until caught and forced to comply) or it faces the situation and implements local tax hikes or rate-payer hikes to cover the cost of compliance.

Note: Changes resulting because of regulatory pressure sometimes mean replacing or changing existing equipment, result in increased chemical costs (e.g., substituting hypochlorite for chlorine typically increases costs threefold), and could easily involve increased energy and personnel costs. Equipment condition, new technology, and financial concerns are all considerations when upgrades or new processes are chosen. In addition, the safety of the process must be considered, of course, because of the demands made by USEPA and OSHA. The potential of harm to workers, the commu-nity, and the environment are all under study, as are the possible long-term effects of chlorination on the human population.

An example of how a change in regulations can force the issue is demonstrated by the demands made by the Occupational Safety and Health Administration (OSHA) and the USEPA in their Process Safety Management (PSM)/Risk Management Planning (RMP) regulations. These regulations put the use of elemental chlorine (and other listed hazard-ous materials) under close scrutiny. Moreover, because of these regulations, plant manag-ers throughout the country are forced to choose which side of a double-edged sword cuts their way the most. One edge calls for full compliance with the regulations (analogous to stuffing the regulation through the eye of a needle); the other edge calls for substi-tutionthat is, replacing elemental chlorine (probably the USEPAs motive in the first place; see the following note) with a non-listed hazardous chemical (e.g., hypochlorite) or a physical (ultraviolet irradiation) disinfectant. Either way, it is a very costly undertaking (Spellman, 2008).

7Introduction

Note: Many of us who have worked in water and wastewater treatment for years char-acterize PSM and RMP regulations as the elemental chlorine killers. You have prob-ably heard the old saying: If you cant do away with something, then regulate it to death.

Water and wastewater treatment plants typically have a useful life of 20 to 50 years before they require expansion or rehabilitation. Collection, interceptor, and distribution pipes have life cycles that can range from 15 to 100 years, depending on the type of mate-rial and where they are laid. Long-term corrosion reduces the carrying capacity of a pipe, thus requiring increasing investments in power and pumping. When water or wastewater pipes age to that point of failure, the result can be contamination of drinking water, the release of wastewater into our surface waters or basements, and high costs to replace the pipes and repair any resulting damage. With pipes, the material used and how the pipe was installed can be a greater indicator of failure than age.

1.2.2 Cash Cows or Cash Dogs?

Maintaining the sustainable operations of water and wastewater treatment facilities is expensive. If funding is not available from federal, state, or local governmental entities, then the facilities must be funded by ratepayers. Water and wastewater treatment plants are usually owned, operated, and managed by the community (the municipality) where they are located. Although many of these facilities are privately owned, the majority of water treatment plants (WTPs) and wastewater treatment plants (WWTPs) are publicly owned treatment works (POTW) (i.e., owned by local government agencies).

These publicly owned facilities are managed and operated onsite by professionals in the field. Onsite management, however, is usually controlled by a board of elected, appointed, or hired directors or commissioners, who set policy, determine budget, plan for expansion or upgrading, hold decision-making power for large purchases, set rates for ratepayers, and in general control the overall direction of the operation.

When final decisions on matters that affect plant performance are in the hands of, for example, a board of directors comprised of elected and appointed city officials, their knowledge of the science, the engineering, and the hands-on problems that those who are onsite must solve can range from comprehensive to nothing. Matters that are of criti-cal importance to those in onsite management may mean little to those on the board. The board of directors may also be responsible for other city services and have an agenda that encompasses more than just the water or wastewater facility. Thus, decisions that affect onsite management can be affected by political and financial concerns that have little to do with the successful operation of a WTP or POTW.

Finances and funding are always of concern, no matter how small or large, well-sup-ported or underfunded, the municipality. Publicly owned treatment works are generally funded from a combination of sources. These include local taxes, state and federal mon-ies (including grants and matching funds for upgrades), and usage fees for water and wastewater customers. In smaller communities, in fact, their water/wastewater (W/WW) plants may be the only city services that actually generate income. This is especially true in water treatment and delivery, which are commonly looked upon as the cash cows of city services. As a cash cow, the water treatment works generates cash in excess of the amount of cash necessary to maintain the treatment works. These treatment works are milked continuously with as little investment as possible, and funds generated by the facility do


not always stay with the facility. Funds can be reassigned to support other city services, so when facility upgrade time rolls around funding for renovations can be problematic. On the other end of the spectrum, spent water (wastewater) treated in a POTW is often looked upon as one of the cash dogs of city services. Typically, these units make only enough money to sustain operations. This is the case, of course, because managers and oversight boards or commissions are fearful, for political reasons, of charging ratepayers too much for treatment services. Some progress has been made, however, in marketing and selling treated wastewater for reuse in industrial cooling applications and some irrigation proj-ects. Moreover, wastewater solids have been reused as soil amendments; also, ash from incinerated biosolids has been used as a major ingredient in forming cement revetment blocks used in areas susceptible to heavy erosion from river and sea inlets and outlets (Drinan and Spellman, 2012).

Planning is essential for funding, for controlling expenses, and for ensuring water and wastewater infrastructure sustainability. The infrastructure we build today will be with us for a long time and, therefore, must be efficient to operate, offer the best solution in meeting the needs of a community, and be coordinated with infrastructure investments in other sectors such as transportation and housing. It is both important and challenging to ensure that a plan is in place to renew and replace it at the right time, which may be years away. Replacing an infrastructure asset too soon means not benefiting from the remain-ing useful life of that asset. Replacing an asset too late can lead to emergency repairs that are significantly more expensive than those that are planned (USEPA, 2012). Additionally, making retrofits to newly constructed infrastructure that was not designed or constructed correctly is expensive. Doing the job correctly the first time requires planning and a cer-tain amount of competence.

1.3 Water/Wastewater Infrastructure Gap

A 2002 USEPA report referenced a water infrastructure gap analysis that compared cur-rent spending trends at the nations drinking water and wastewater treatment facilities to the expenses that they can expect to incur for both capital and operations and mainte-nance costs. The gap is the difference between projected and needed spending and was found to be over $500 billion over a 20-year period. This important gap analysis study is just as pertinent today as it was 10 years ago. Moreover, this text draws upon tenets presented in the USEPA analysis in formulating many of the basic points and ideas pre-sented here.

DID YOU KNOW?

More than 50% of Americans drink bottled water occasionally or rely upon it as their major source of drinking wateran astounding fact given the high quality and low cost of U.S. tap water.

9Introduction

1.4 Energy Efficiency: Water/Wastewater Treatment Operations

Obviously, as the title of this text implies, we are concerned with water and wastewa-ter infrastructure. This could mean we are concerned with the pipes, treatment plants, and other critical components that deliver safe drinking water to our taps and remove wastewater (sewage) from our homes and other buildings. Although any component or system that makes up water and wastewater infrastructure is important, remember that no water-related infrastructure can function without the aid of some motive force. This motive force (energy source) can be provided by gravitational pull, mechanical means, or electrical energy. We simply cannot sustain the operation of water and wastewater infra-structure without energy. As a case in point, consider that drinking water and waste-water systems account for approximately 3 to 4% of energy use in the United States and contribute over 45 million tons of greenhouse gases annually. Further, drinking water and wastewater plants are typically the largest energy consumers of municipal govern-ments, accounting for 30 to 40% of total energy consumed. As a percent of operating costs for drinking water systems, energy can represent as much as 40% of those costs and is expected to increase 20% over the next 15 years due to population growth and tightening drinking water regulations.

Not all the news is bad, however. Studies estimate potential savings of 15 to 30% that are readily achievable in water and wastewater treatment plants, with substantial financial returns in the thousands of dollars and within payback periods of only a few months to a few years.

In the chapters that follow, we begin our discussion of energy efficiency for sustainable infrastructure in water and wastewater treatment plant operations with brief characteriza-tions of the water and wastewater treatment industries. We then move on to a brief discus-sion of the basics of energy. We follow this with a discussion on determining energy usage, cutting energy usage and costs, and renewable energy options.

References and Recommended Reading

Drinan, J.E. and Spellman, F.R. (2012). Water and Wastewater Treatment: A Guide for the Nonengineering Professional, 2nd ed., CRC Press, Boca Raton, FL.

Elkington, J. (1999). Cannibals with Forks, Wiley, New York.Spellman, F.R. (2008). Handbook of Water and Wastewater Treatment Plant Operations, 2nd ed., CRC

Press, Boca Raton, FL.USEPA. (2002). The Clean Water and Drinking Water Infrastructure Gap Analysis, EPA-816-R-02-020, U.S.

Environmental Protection Agency, Washington, DC.USEPA. (2012). Frequently Asked Questions: Water Infrastructure and Sustainability, U.S. Environmental

Protection Agency, Washington, DC, http://water.epa.gov/infrastructure/sustain/si_faqs.cfm.

11

2Characteristics of the Wastewater and Drinking Water Industries

Wastewater Treatment

According to the Code of Federal Regulations (CFR) 40 CFR Part 403, regulations were established in the late 1970s and early 1980s to help Publicly Owned Treatment Works (POTW) control industrial discharges to sewers. These regulations were designed to prevent pass-through and interference at the treatment plants and interference in the collection and transmission systems.

Pass-through occurs when pollutants literally pass through a POTW without being properly treated, and cause the POTW to have an effluent violation or increase the mag-nitude or duration of a violation.

Interference occurs when a pollutant discharge causes a POTW to violate its permit by inhibiting or disrupting treatment processes, treatment operations, or processes related to sludge use or disposal.

Drinking Water Treatment

Municipal water treatment operations and associated treatment unit processes are designed to provide reliable, high quality water service for customers, and to preserve and protect the environment for future generations.

Water management officials and treatment plant operators are tasked with exercising responsible financial management, ensuring fair rates and charges, providing respon-sive customer service, providing a consistent supply of safe potable water for consump-tion by the user, and promoting environmental responsibility.

The Honeymoon Is Over

The modern public water supply industry has come into being over the course of the last century. From the period known as the Great Sanitary Awakening, that eliminated waterborne epidemics of diseases such as cholera and typhoid fever at the turn of the last century, we have built elaborate utility enterprises consisting of vast pipe networks and amazing high-tech treatment systems. Virtually all of this progress has been financed through local revenues. But in all this time, there has seldom been a need to provide for more than modest amounts of pipe replacement, because the pipes last so very long. We have been on an extended honeymoon made possible by the long life of the pipes and the fact that our water systems are relatively young. Now the honeymoon is over.

AWWA (2001)


2.1 Introduction

In this chapter, a discussion of the characteristics of the wastewater and drinking water industries provides a useful context for understanding the differences between the indus-tries and how these differences necessitate the use of different methods for estimating needs and costs and for instituting energy efficiency procedures to ensure sustainability (USEPA, 2002).

2.1.1 Wastewater and Drinking Water Terminology

To study any aspect of wastewater and drinking water treatment operations, it is nec-essary to master the language associated with the technology. Each technology has its own terms with its own accompanying definitions. Many of the terms used in water/wastewater treatment are unique; others combine words from many different technologies and professions. One thing is certainwater/wastewater operators without a clear under-standing of the terms related to their profession are ill equipped to perform their duties in the manner required. Although this text includes a glossary of terms at the end, we list and define many of the terms used right up front. Experience has shown that an early introduc-tion to keywords is a benefit to readers. An upfront introduction to key terms facilitates a more orderly, logical, systematic learning activity. Those terms not defined in this section are defined as they appear in the text.

AbsorbTo take in. Many things absorb water.Acid rainThe acidic rainfall that results when rain combines with sulfur oxides emissions

from combustion of fossil fuels (coal, for example).Acre-feet (acre-foot)An expression of water quantity. One acre-foot will cover 1 acre of

ground 1 foot deep. An acre-foot contains 43,560 cubic feet, 1233 cubic meters, or 325,829 gallons (U.S). Abbreviated as ac-ft.

Activated carbonDerived from vegetable or animal materials by roasting in a vacuum fur-nace. Its porous nature gives it a very high surface area per unit mass, as much as 1000 square meters per gram, which is 10 million times the surface area of 1 gram of water in an open container. Used in adsorption (see definition), activated carbon adsorbs substances that are not or are only slightly adsorbed by other methods.

Activated sludgeThe solids formed when microorganisms are used to treat wastewater using the activated sludge treatment process. It includes organisms, accumulated food materials, and waste products from the aerobic decomposition process.

AdsorptionThe adhesion of a substance to the surface of a solid or liquid. Adsorption is often used to extract pollutants by causing them to attach to such adsorbents as activated carbon or silica gel. Hydrophobic (water-repulsing) adsorbents are used to extract oil from waterways in oil spills.

Advanced wastewater treatmentTreatment technology to produce an extremely high-qual-ity discharge.

AerationThe process of bubbling air through a solution, sometimes cleaning water of impurities by exposure to air.

AerobicConditions in which free, elemental oxygen is present. Also used to describe organisms, biological activity, or treatment processes that require free oxygen.

AgglomerationFloc particles colliding and gathering into a larger settleable mass.


Air gapThe air space between the free-flowing discharge end of a supply pipe and an unpressurized receiving vessel.

Algae bloomA phenomenon whereby excessive nutrients within a river, stream, or lake cause an explosion of plant life that results in depletion of the oxygen in the water needed by fish and other aquatic life. Algae bloom is usually the result of urban runoff (of lawn fertilizers, etc.). The potential tragedy is that of a fish kill, where the stream life dies in one mass execution.

AlumAluminum sulfate; a standard coagulant used in water treatment.AmbientThe expected natural conditions that occur in water unaffected or uninfluenced

by human activities.AnaerobicConditions in which no oxygen (free or combined) is available. Also used to

describe organisms, biological activity, or treatment processes that function in the absence of oxygen.

AnoxicConditions in which no free, elemental oxygen is present. The only source of oxy-gen is combined oxygen, such as that found in nitrate compounds. Also used to describe biological activity of treatment processes that function only in the pres-ence of combined oxygen.

AquiferA water-bearing stratum of permeable rock, sand, or gravel.Aquifer systemA heterogeneous body of introduced permeable and less permeable mate-

rial that acts as a water-yielding hydraulic unit of regional extent.Artesian waterA well tapping a confined or artesian aquifer in which the static water

level stands above the top of the aquifer. The term is sometimes used to include all wells tapping confined water. Wells with water levels above the water table are said to have positive artesian head (pressure), and those with water levels below the water table have negative artesian head.

Average monthly discharge limitationThe highest allowable discharge over a calendar month.

Average weekly discharge limitationThe highest allowable discharge over a calendar week.BackflowReversal of flow when pressure in a service connection exceeds the pressure in

the distribution main.BackwashFluidizing filter media with water, air, or a combination of the two so that indi-

vidual grains can be cleaned of the material that has accumulated during the filter run.

BacteriaAny of a number of one-celled organisms, some of which cause disease.Bar screenA series of bars formed into a grid used to screen out large debris from influ-

ent flow.BaseA substance that has a pH value between 7 and 14.BasinA groundwater reservoir defined by the overlying land surface and underlying

aquifers that contain water stored in the reservoir.Beneficial use of waterThe use of water for any beneficial purpose. Such uses include domes-

tic use, irrigation, recreation, fish and wildlife, fire protection, navigation, power, industrial use, etc. The benefit varies from one location to another and by custom. What constitutes beneficial use is often defined by statute or court decisions.

Biochemical oxygen demand (BOD5)The oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter.

BiosolidsSolid organic matter recovered from a sewage treatment process and used espe-cially as fertilizer or soil amendment; usually referred to in the plural (Merriam-Websters Collegiate Dictionary, 10th ed., 1998).


Note: In this text, biosolids is generally used to replace the standard term sludge. It is the authors view that sludge is an ugly four-letter word inappropriate for describing biosolids. Biosolids can be reused; they have some value. Because biosolids have value, they certainly should not be classified as a waste product, and when the topic of biosol-ids for beneficial reuse is addressed, it is made clear that they are not a waste product.

BiotaAll the species of plants and animals indigenous to a certain area.Boiling pointThe temperature at which a liquid boils. The temperature at which the vapor

pressure of a liquid equals the pressure on its surface. If the pressure of the liquid varies, the actual boiling point varies. The boiling point of water is 212F or 100C.

BreakpointPoint at which chlorine dosage satisfies chlorine demand.BreakthroughIn filtering, when unwanted materials start to pass through the filter.BufferA substance or solution that resists changes in pH.Calcium carbonateCompound principally responsible for hardness.Calcium hardnessPortion of total hardness caused by calcium compounds.Carbonaceous biochemical oxygen demand (CBOD5 )The amount of biochemical oxygen

demand that can be attributed to carbonaceous material.Carbonate hardnessCaused primarily by compounds containing carbonate.Chemical oxygen demand (COD)The amount of chemically oxidizable materials present

in the wastewater.ChlorinationDisinfection of water using chlorine as the oxidizing agent.ClarifierA device designed to permit solids to settle or rise and be separated from the

flow. Also known as a settling tank or sedimentation basin.CoagulationThe neutralization of the charges of colloidal matter.ColiformA type of bacteria used to indicate possible human or animal contamination

of water.Combined sewerA collection system that carries both wastewater and stormwater flows.ComminutionA process to shred solids into smaller, less harmful particles.Composite sampleA combination of individual samples taken in proportion to flow.Connate waterPressurized water trapped in the pore spaces of sedimentary rock at the

time it was deposited. It is usually highly mineralized.Consumptive use(1) The quantity of water absorbed by crops and transpired or used

directly in the building of plant tissue, together with the water evaporated from the cropped area. (2) The quantity of water transpired and evaporated from a cropped area or the normal loss of water from the soil by evaporation and plant transpiration. (3) The quantity of water discharged to the atmosphere or incorpo-rated in the products of the process in connection with vegetative growth, food processing, or an industrial process.

Contamination (water)Damage to the quality of water sources by sewage, industrial waste, or other material.

Cross-connectionA connection between a storm-drain system and a sanitary collection system, a connection between two sections of a collection system to handle antici-pated overloads of one system, or a connection between drinking (potable) water and an unsafe water supply or sanitary collection system.

Daily dischargeThe discharge of a pollutant measured during a calendar day or any 24-hour period that reasonably represents a calendar day for the purposes of sam-pling. Limitations expressed as weight are total mass (weight) discharged over the day. Limitations expressed in other units are average measurements of the day.


Daily maximum dischargeThe highest allowable values for a daily discharge.Darcys lawAn equation for the computation of the quantity of water flowing through

porous media. Darcys law assumes that the flow is laminar and that inertia can be neglected. The law states that the rate of viscous flow of homogeneous fluids through isotropic porous media is proportional to, and in the direction of, the hydraulic gradient.

Detention timeThe theoretical time water remains in a tank at a given flow rate.DewateringThe removal or separation of a portion of water present in a sludge or slurry.DiffusionThe process by which both ionic and molecular species dissolved in water move

from areas of higher concentration to areas of lower concentration.Discharge monitoring report (DMR)The monthly report required by the treatment plants

National Pollutant Discharge Elimination System (NPDES) discharge permit.DisinfectionWater treatment process that kills pathogenic organisms.Disinfection byproducts (DBPs)Chemical compounds formed by the reaction of disinfec-

tant with organic compounds in water.Dissolved oxygen (DO)The amount of oxygen dissolved in water or sewage.

Concentrations of less than five parts per million (ppm) can limit aquatic life or cause offensive odors. Excessive organic matter present in water because of inadequate waste treatment and runoff from agricultural or urban land gener-ally causes low DO.

Dissolved solidsThe total amount of dissolved inorganic material contained in water or wastes. Excessive dissolved solids make water unsuitable for drinking or indus-trial uses.

Domestic consumption (use)Water used for household purposes such as washing, food preparation, and showers. The quantity (or quantity per capita) of water con-sumed in a municipality or district for domestic uses or purposes during a given period, it sometimes encompasses all uses, including the quantity wasted, lost, or otherwise unaccounted for.

DrawdownLowering the water level by pumping. It is measured in feet for a given quantity of water pumped during a specified period, or after the pumping level has become constant.

Drinking water standardsEstablished by state agencies, the U.S. Public Health Service, and the U.S. Environmental Protection Agency (USEPA) for drinking water in the United States.

EffluentSomething that flows out, usually a polluting gas or liquid discharge.Effluent limitationAny restriction imposed by the regulatory agency on quantities, dis-

charge rates, or concentrations of pollutants discharged from point sources into state waters.

EnergyIn scientific terms, the ability or capacity of doing work. Various forms of energy include kinetic, potential, thermal, nuclear, rotational, and electromagnetic. One form of energy may be changed to another, as when coal is burned to produce steam to drive a turbine, which produces electric energy.

ErosionThe wearing away of the land surface by wind, water, ice, or other geologic agents. Erosion occurs naturally from weather or runoff but is often intensified by human land use practices.

EutrophicationThe process of enrichment of water bodies by nutrients. Eutrophication of a lake normally contributes to its slow evolution into a bog or marsh and ultimately to dry land. Eutrophication may be accelerated by human activities, thereby speeding up the aging process.


EvaporationThe process by which water becomes a vapor at a temperature below the boiling point.

FacultativeOrganisms that can survive and function in the presence or absence of free, elemental oxygen.

Fecal coliformThe portion of the coliform bacteria group that is present in the intestinal tracts and feces of warm-blooded animals.

Field capacityThe capacity of soil to hold water. It is measured as the ratio of the weight of water retained by the soil to the weight of the dry soil.

FiltrationThe mechanical process that removes particulate matter by separating water from solid material, usually by passing it through sand.

FlocSolids that join to form larger particles that will settle better.FlocculationSlow mixing process in which particles are brought into contact, with the

intent of promoting their agglomeration.FlumeA flow rate measurement device.FluoridationChemical addition to water to reduce incidence of dental caries in children.Food-to-microorganisms ratio (F/M)An activated sludge process control calculation based

on the amount of food (BOD5 or COD) available per pound of mixed liquor volatile suspended solids.

Force mainA pipe that carries wastewater under pressure from the discharge side of a pump to a point of gravity flow downstream.

Grab sampleAn individual sample collected at a randomly selected time.GraywaterWater that has been used for showering, clothes washing, and faucet uses.

Kitchen sink and toilet water is excluded. This water has excellent potential for reuse as irrigation for yards.

GritHeavy inorganic solids, such as sand, gravel, eggshells, or metal filings.GroundwaterThe supply of fresh water found beneath the surface of the Earth (usually

in aquifers) often used for supplying wells and springs. Because groundwater is a major source of drinking water, concern is growing over areas where leaching agricultural or industrial pollutants or substances from leaking underground storage tanks (USTs) are contaminating groundwater.

Groundwater hydrologyThe branch of hydrology that deals with groundwater: its occur-rence and movements, its replenishment and depletion, the properties of rocks that control groundwater movement and storage, and the methods of investiga-tion and use of groundwater.

Groundwater rechargeThe inflow to a groundwater reservoir.Groundwater runoffA portion of runoff that has passed into the ground, has become

groundwater, and has been discharged into a stream channel as spring or seepage water.

HardnessThe concentration of calcium and magnesium salts in water.Head lossAmount of energy used by water in moving from one point to another.Heavy metalsMetallic elements with high atomic weights, such as mercury, chromium,

cadmium, arsenic, and lead. They can damage living things at low concentrations and tend to accumulate in the food chain.

Holding pondA small basin or pond designed to hold sediment-laden or contaminated water until it can be treated to meet water quality standards or used in some other way.

Hydraulic cleaningCleaning pipe with water under enough pressure to produce high water velocities.


Hydraulic gradientA measure of the change in groundwater head over a given distance.Hydraulic headThe height above a specific datum (generally sea level) that water will rise

in a well.Hydrologic cycle (water cycle)The cycle of water movement from the atmosphere to the

Earth and back to the atmosphere through various processes. These processes include precipitation, infiltration, percolation, storage, evaporation, transpiration, and condensation.

HydrologyThe science dealing with the properties, distribution, and circulation of water.ImpoundmentA body of water such as a pond, confined by a dam, dike, floodgate, or

other barrier, and used to collect and store water for future use.Industrial wastewaterWastes associated with industrial manufacturing processes.InfiltrationThe gradual downward flow of water from the surface into soil material.Infiltration/inflowExtraneous flows in sewers; simply, inflow is water discharged into

sewer pipes or service

water and wastewater infrastructure spellman

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