Water Treatment Residuals Management for Small · PDF fileWater Treatment Residuals Management...

Water Treatment Residuals Management for Small Systems

Subject Area:Water Resources and Environmental Sustainability

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Prepared by:Nancy E. McTigue and David A. Cornwell, Ph.D., P.E. BCEEEE&T, Inc.712 Gum Rock CourtNewport News, VA 23606

Jointly sponsored by:Water Research Foundation6666 W. Quincy AveDenver, Coloradoand

U.S. Enviromental Protection AgencyWashington, D.C.



DISCLAIMER

This study was jointly funded by the Water Research Foundation (the Foundation) and the U.S. Environmental Protection Agency (USEPA) under Cooperative Agreement No. X-83294801. The Foundation and USEPA assume no responsibility for the content of the research study reported in this publication or for the opinions or statements

of fact expressed in the report. The mention of trade names for commercial products does not represent or imply the approval of the Foundation or USEPA. This report is presented solely for informational purposes.

Copyright © 2009by Water Research Foundation

ALL RIGHTS RESERVED. No part of this publication may be copied, reproduced

or otherwise utilized without permission.

ISBN 978-1-60573-037-0

Printed in the U.S.A.


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CONTENTS LIST OF TABLES ........................................................................................................................ ix LIST OF FIGURES ....................................................................................................................... xi FOREWORD............................................................................................................................... xiii ACKNOWLEDGMENTS ............................................................................................................ xv EXECUTIVE SUMMARY ........................................................................................................ xvii CHAPTER 1: INTRODUCTION...................................................................................................1 How to Use this Manual ......................................................................................................2 CHAPTER 2: WHAT KIND OF RESIDUALS ARE PRODUCED?............................................3 What Residuals are Produced ..............................................................................................3 Coagulation Waste Streams .................................................................................................7 Softening Waste Streams .....................................................................................................9 Ion Exchange and Media Adsorption Residuals................................................................10 Membrane and Reverse Osmosis Residuals ......................................................................11 Iron and Manganese Oxidation Residuals .........................................................................12 CHAPTER 3: QUANTITIES AND CHARACTERISTICS .........................................................13 Coagulant Solids ................................................................................................................13 Lime Residuals...................................................................................................................18 Manganese and Iron Removal Residuals...........................................................................19 Ion Exchange and Media Adsorption Residuals................................................................19 Spent Filter Backwash Water.............................................................................................21 Membrane Residuals..........................................................................................................22 Spent GAC and Filtration Media .......................................................................................23 Precoat Filtration Residuals ...............................................................................................23 Slow Sand Filtration Residuals..........................................................................................23 Residuals Characteristics ...................................................................................................24 Physical Properties.................................................................................................24 Characteristics of Predominately Liquid Sludge ...................................................26 Characteristics of Predominately Solid Sludge......................................................27 Chemical Characteristics .......................................................................................27 CHAPTER 4: REGULATIONS ...................................................................................................29 Clean Water Act.................................................................................................................29 Discharge to Sewers (Pretreatment Program)........................................................30 Direct Discharge to Receiving Stream (NPDES Program)....................................31 Filter Backwash and Recycling Rule (FBRR) ...................................................................31 Safe Drinking Water Act ...................................................................................................32 Underground Injection ...........................................................................................32


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On-Site Dewatering ...............................................................................................33 Resource Conservation and Recovery Act of 1976 ...........................................................33 Solids Disposal in a Municipal Solid Waste Landfill ............................................34 Solids Disposal in a Hazardous Waste Landfill.....................................................34 Land Application of Liquid Residuals...................................................................36 The Atomic Energy Act of 1954, As Amended.................................................................36 Disposal of Residuals Containing Radioactivity ...................................................36 Department of Transportation (DOT) Regulations (49 CFR 171 to 180) .........................37 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) .............................................................................................................38 CHAPTER 5: THICKENING AND DEWATERING .................................................................39 Pumps and Piping ..............................................................................................................40 Equalization .......................................................................................................................41 Gravity Thickening ............................................................................................................42 Thickening Tanks...................................................................................................42 Plate Settlers...........................................................................................................43 Conditioning ..........................................................................................................43 Non-Mechanical Dewatering .............................................................................................43 Sand Drying Beds Description...............................................................................45 Solar Drying Bed or Evaporation Ponds................................................................46 Dewatering Lagoons ..............................................................................................46 Freeze-Thaw Beds .................................................................................................47 Mechanical Dewatering .....................................................................................................48 Centrifuges.............................................................................................................49 Pressure Filter Press...............................................................................................51 Belt Filter Press......................................................................................................51 Vacuum Filter ........................................................................................................53 CHAPTER 6: SPECIAL WASTES..............................................................................................55 Arsenic ...............................................................................................................................55 Regulations ............................................................................................................57 Processes ................................................................................................................58 Residuals Quantities and Characteristics ...............................................................64 Treatment of Arsenic – Containing Liquid Residuals ...........................................66 Handling of Solids From Arsenic Removal...........................................................70 Radioactivity ......................................................................................................................70 Residuals Production .............................................................................................70 Characterization .....................................................................................................74 Regulations ............................................................................................................75 State TENORM Regulations..................................................................................76 Ultimate Disposal Options.....................................................................................78 Mixed Waste ......................................................................................................................81 CHAPTER 7: LANDFILL............................................................................................................83 Nonhazardous Landfills .....................................................................................................83


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Municipal Solid Waste Landfills ...........................................................................83 Monofill .................................................................................................................84 Hazardous Waste Landfill..................................................................................................85 What Data Would be Required to Dispose of Material in a Hazardous Waste Facility?......................................................................................................86 Low Level Radioactive Waste Landfill (LLRW) ..............................................................86 What Data Will be Needed for Disposal at a LLRW Landfill? .............................87 CHAPTER 8: LAND APPLICATION AND BENEFICIAL USES ............................................89 Background ........................................................................................................................89 What Type of Data are Needed to Use Land Application? ...................................91 Beneficial Uses ..................................................................................................................93 Regulatory Evaluation ...........................................................................................94 Residuals Characterization.....................................................................................94 User Requirements.................................................................................................97 Preliminary Economic Analysis ............................................................................97 Noneconomic Analysis ..........................................................................................98 Contract Haulers ................................................................................................................98 CHAPTER 9: SEWER AND DIRECT DISCHARGE.................................................................99 Discharge by Connection to a POTW................................................................................99 What Kind of Data will a POTW Require? ...........................................................99 Equalization .........................................................................................................100 Direct Discharge to Surface Water ..................................................................................100 CHAPTER 10: UNDERGROUND INJECTION CONTROL WELLS.....................................105 Background ......................................................................................................................105 What are the Requirements for UIC Well Disposal?.......................................................106 Feasibility.........................................................................................................................107 What Data are Needed to be Able to Use This Option? ......................................107 CHAPTER 11: SUMMARY.....................................................................................................109 APPENDIX A: STATE, REGIONAL, FEDERAL AND TRIBAL CONTACTS.....................111 APPENDIX B: TCLP CONTAMINANTS AND REGULATORY LEVELS...........................123 REFERENCES ............................................................................................................................125 ABBREVIATIONS .....................................................................................................................129


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TABLES

1.1 Water system categories ......................................................................................................1 2.1 Small system regulatory summary.......................................................................................4 2.2 Regulated contaminant list (partial) and possible removal technologies.............................5 2.3 Residual type by treatment technology................................................................................6 3.1 Examples of estimated sludge production .........................................................................17 5.1 Range of cake solid concentrations obtainable..................................................................39 6.1 Summary of residuals and management methods for arsenic treatment technologies ......55 6.2 Summary of example residuals quantity from arsenic processes ......................................64 6.3 Arsenic residuals sample characterization .........................................................................65 6.4 Concentration of arsenic in residuals.................................................................................66 6.5 Summary of treatment results for removing arsenic from liquid arsenic waste ................67 6.6 Radionuclides MCLs .........................................................................................................70 6.7 Summary of treatment technologies for removal of naturally occurring radionuclides

in water ....................................................................................................................71 6.8 SPARRC elements .............................................................................................................74 6.9 Disposal requirements of certain states..............................................................................77 6.10 Common disposal considerations for residuals containing radioactivity ..........................78 7.1 Operating low level radioactive waste landfills.................................................................87 8.1 Important residuals quality parameters for land applying coagulant residuals..................92 8.2 Recommended cumulative metal limits for cropland ........................................................93 8.3 Physical test parameters useful for beneficial use .............................................................95 8.4 Chemical test parameters useful for residuals beneficial use ............................................96


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9.1 Parameters of importance to a POTW ...............................................................................99 9.2 Example in-stream water quality guidelines and standards .............................................102


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FIGURES 2.1 Major residual streams commonly generated by coagulation water treatment plants .........8 2.2 Waste producing processes in softening plants ...................................................................9 2.3 Schematic of ion exchange process with upflow regeneration..........................................11 3.1 Quantity of dry alum solids produced under different conditions .....................................15 3.2 Volume of alum sludge produced under different conditions ...........................................15 3.3 Quantity of dry ferric solids produced under different conditions ....................................16 3.4 Volume of ferric sludge produced under different conditions...........................................16 3.5 Example of annual sludge production variation by month ................................................18 3.6 Estimated of quantity of adsorption media required at different flows and contact

time ........................................................................................................................21 3.7 Decision tree for the disposal of liquid (non-solid) residuals ............................................25 3.8 Decision tree for the disposal of solids residuals...............................................................26 4.1 Federal regulations governing the disposal of residuals ....................................................30 4.2 Hazardous waste determination decision tree....................................................................34 5.1 Sludge handling options.....................................................................................................40 5.2 Nonmechanical dewatering................................................................................................44 5.3 Solids dewatered by two different nonmechanical processes – drying beds and

freeze-thaw.............................................................................................................44 5.4 Example centrifuge system ................................................................................................49 5.5 Schematic of skid mounted centrifuge system...................................................................50 5.6 Andritz belt filter press – Waco, Texas, USA ...................................................................52 6.1 Schematic of ion exchange process with regeneration for arsenic removal ......................59 6.2 Schematic of membrane process for arsenic removal........................................................59


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6.3 Schematic of AA adsorption process with regeneration for arsenic removal....................60 6.4 Schematic of oxidation-filtration iron and manganese removal process for arsenic

removal ..................................................................................................................62 6.5 Schematic of iron and manganese (greensand) filtration process for arsenic removal......63 6.6 Arsenic residuals treatment options ...................................................................................67 6.7 Arsenic residuals handling and disposal decision tree.......................................................69 6.8 Decision Tree 1: Solids residuals disposal containing radioactivity ................................79 6.9 Decision Tree 2: Liquid residuals disposal containing radioactivity................................80 6.10 Decision Tree 3: Liquid residuals disposal – intermediate processing.............................81 7.1 Typical municipal solids waste landfill .............................................................................84 7.2 Schematic of hazardous waste landfill after closure..........................................................86


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FOREWORD

The Water Research Foundation is a nonprofit corporation that is dedicated to the implementation of a research effort to help utilities respond to regulatory requirements and traditional high-priority concerns of the industry. The research agenda is developed through a process of consultation with subscribers and drinking water professionals. Under the umbrella of a Strategic Research Plan, the Research Advisory Council prioritizes the suggested projects based upon current and future needs, applicability, and past work; the recommendations are forwarded to the Board of Trustees for final selection. The Foundation also sponsors research projects through the unsolicited proposal process; the Collaborative Research, Research Application, and Tailored Collaboration programs; and various joint research efforts with organizations such as the U.S. Environmental Protection Agency, the U.S. Bureau of Reclamation, and the Association of California Water Agencies. This publication is a result of one of these sponsored studies, and it is hoped that its findings will be applied in communities throughout the world. The following report serves not only as a means of communicating the results of the water industry’s centralized research program but also as a tool to enlist the further support of the nonmember utilities and individuals. Projects are managed closely from their inception to the final report by the Foundation’s staff and large cadre of volunteers who willingly contribute their time and expertise. The Foundation serves a planning and management function and awards contracts to other institutions such as water utilities, universities, and engineering firms. The funding for this research effort comes primarily from the Subscription Program, through which water utilities subscribe to the research program and make an annual payment proportionate to the volume of water they deliver and consultants and manufactures subscribe based on their annual billings. The program offers a cost-effective and fair method for funding research in the public interest. A broad spectrum of water supply issues is addressed by the Foundation’s research agenda: resources, treatment, and operations, distribution and storage, water quality and analysis, toxicology, economics, and management. The ultimate purpose of the coordinated effort is to assist water suppliers to provide the highest possible quality of water economically and reliably. The true benefits are realized when the results are implemented at the utility level. The Foundation’s trustees are pleased to offer this publication as a contribution toward that end. David E. Rager Robert C. Renner, P.E. Chair, Board of Trustees Executive Director Water Research Foundation Water Research Foundation


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ACKNOWLEDGMENTS

The authors would like to thank Dr. Kenan Ozekin, the Water Research Foundation

Project Manager and the members of the Project Advisory Committee, including − Jennifer Moller, Ground Water and Drinking Water Office, US Environmental Protection Agency, Washington, D.C.; Jerry W. Gibbs, P.E., Park City Municipal Corporation, Park City, UT; Jerry Biberstine, National Rural Water Association, Denver, CO. The authors also thank the group of experts who provided insight and guidance for this

project. They include − Joy Barrett, Ph.D., Rural Community Assistance Partnership (RCAP), Boulder, CO; Bill Hogrewe, Ph.D., P.E., Rural Community Assistance Corporation, Boulder, CO; Christopher A. Impellitteri, Ph.D., National Risk Management Research Laboratory, US Environmental Protection Agency, Cincinnati, OH; Cynthia Klevens, New Hampshire Department of Environmental Services, Concord, NH; Pat Kline, American Water Works Association, Denver, CO; Stephen Roy, New Hampshire Department of Environmental Services, Concord, NH; John Scheltens, City of Hot Springs, SD; Robert Wichser, Rivanna Water and Sewer Authority, Charlottesville, VA; Mel Aust, Hidden Valley Lake Community Services District, Hidden Valley Lake, CA.


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EXECUTIVE SUMMARY This document was prepared to aid small system owners, consultants and regulators better understand the issues and constraints involved with the treating and disposal of residuals created by water treatment systems. The document is designed to provide information on processes utilized by small systems. In this publication, “small systems” are systems that serve 10,000 or fewer customers.

This document contains the information and methodology that small system personnel need to make informed decisions about their residuals. The Water Research Foundation previously published “Water Treatment Residuals Engineering” (2006), a comprehensive guidance manual on this topic. This work is based on that previous report, but is focused on processes utilized by small systems.

Water systems serving a small number of customers generally need to comply with the same regulatory requirements as do larger systems, but they rarely have the resources to research all the different options available to provide safe and affordable drinking water. This is particularly true for systems that need to change treatment to comply with a new regulation, and in doing so, produce a new type of residual.

All water treatment processes produce some type of waste product. It is important for water system owners to dispose of this material in an affordable manner that meets all regulations. When a water system needs to install a new treatment process, handling and disposal of the waste material, or residuals is often the most costly and complicated step of the new treatment process, but unfortunately it is a step that is often ignored until the new process is in place. This document first presents information on how to determine the type, the amount and the characteristics of residuals produced by water treatment processes (Chapters 2, and 3.) Then, regulatory constraints for handling and disposal of residuals are described (Chapter 4.) Chapter 5 describes how residual material can be conveyed and also various means of dewatering the residuals. Arsenic and radioactivity-bearing residuals are discussed in depth in Chapter 6. Finally, Chapters 7 through 10 describe the various methods available for the ultimate disposal of water treatment residuals.

TYPES OF RESIDUALS

Water treatment processes are utilized to remove contaminants from water or to alter the

contaminant properties in order to produce a potable water. All water treatment processes that remove contaminants produce a waste by-product. That by-product may be liquid, solid, a mixture of the two, or a gaseous vapor. These water treatment plant wastes are referred to as residuals. The names of individual waste streams are generally a function of how the residual is produced. There are five general types of water treatment processes that produce residuals. The first is produced at those plants that coagulate and oxidize a surface water to remove particles (both organic and inorganic) and dissolved contaminants such as color, organic carbon, iron, manganese, and occasionally trace metals. These coagulation plants produce two major residuals, sedimentation (or clarifier) sludge and spent filter backwash water (SFBW). The second type of treatment plants are those that practice chemical softening for the removal of calcium and magnesium. These plants may also remove trace metals, radioactivity,


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and particles if surface water is being treated. These plants also produce a clarifier sludge and spent filter backwash water. Ion exchange processes as their name implies are used to remove cation or anion contaminants such as calcium and magnesium, arsenic, nitrate, and barium. These processes produce a brine residual as well as spent rinse water. There are also adsorption processes that may produce similar types of residuals. Some adsorption processes use “throw away media” such that the residual produced is the spent adsorption material. Adsorption media may also need to be backwashed so that a spent backwash water is produced.

The fourth general category of treatment is when membranes are used to remove particulates or dissolved solids. In this case a concentrate is produced which consists of concentrated levels of the raw water contaminants that the membrane has rejected as well as any additives that may have been used prior to membrane treatment. Finally, gaseous residuals are produced by air stripping processes that release vapor to the atmosphere. These releases are primarily volatile organic compounds and radon.

QUANTITIES AND CHARACTERISTICS

The amount of material generated by a water treatment process is the first piece of

information needed in order to plan for its treatment and disposal. Chapter 3 presents equations, graphs and measurement techniques that system personnel can use to estimate the quantity of residuals produced by different technologies. Also presented is a description of the methodology used to determine if a material is a solid or a liquid, and the testing USEPA requires to be used to determine if a material is hazardous.

REGULATIONS

Of particular importance to the disposal of residuals are the following federal regulations: � Clean Water Act � Resource Conservation and Recovery Act � Safe Drinking Water Act � Filter Backwash and Recycling Rule � Atomic Energy Act � Hazardous Materials Transportation Act

How these laws affect residuals disposal is discussed in Chapter 4.

SPECIAL WASTES

Residuals from water treatment processes designed to remove arsenic and radioactive

material pose special challenges to utilities. Not only can they contain high levels of the contaminant the treatment system has targeted, but they can also contain high levels of any contaminant that is present in the raw water. High levels of contaminants in residuals can result in the material being categorized as hazardous or radioactive. In that situation, the material has to be disposed of in specialized landfills, which is typically quite expensive. Chapter 6 discusses these residuals.


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DEWATERING AND ULTIMATE DISPOSAL

Chapters are included that describe the various methods available to dewater residuals and to dispose of the resulting material. Descriptions, design parameters and expected results of nonmechanical dewatering practices are described in Chapter 5. An introduction to mechanical dewatering devices is also included. Water treatment residuals can be disposed of by means of:

� Landfill � Land Application � Beneficial Reuse � Sewer or Direct Discharge � Underground Injection Control wells

Each of these methods requires compliance with regulations and restrictions. These are described in Chapters 7 through 10. Finally, since many states have authority to control the ultimate disposal of residuals, all of the state contacts in the drinking water, UIC and radiation programs are included in Appendix A.


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CHAPTER 1

INTRODUCTION

Nearly all water treatment processes produce some type of waste product. It is important for water system owners to dispose of this material in an affordable manner that meets all regulations. When a water system needs to install a new treatment process, the handling and disposal of the waste material, or residuals is often the most costly and complicated step of the new treatment process, but unfortunately it is a step that is often ignored until the new process is in place. This document was prepared to aid small system owners, consultants and regulators better understand the issues and constraints involved with the treating and disposal of the by-products water treatment systems create when they treat their water. It is aimed at “small systems,” which, in this publication, are systems that serve 10,000 or fewer customers.

The size of a water treatment utility is usually classified by USEPA according to the number of customers it serves. Table 1.1, adapted from USEPA’s Office of Ground Water shows the range of water production flows that would be expected at plants serving the populations shown. In order to estimate the amount of residuals produced by a water plant the amount of water treated – the flow- is needed.

This document is meant to assist those systems serving fewer than 10,000 people. From Table 1.1, it can be seen that systems serving 10,000 or fewer people will typically produce 1.5 mgd or less. USEPA estimates that there are about 48,000 of these systems, serving a population of 52.4 million, which is about 18 percent of the U.S. population. There are also more than 20,000 nontransient, noncommunity water systems (NTNCWSs) and nearly 100,000 TNCWSs, or transient noncommunity water systems (USEPA 1999). Most systems serving fewer than 10,000 customers use groundwater as a source. Water systems serving a small number of customers need to comply with the same regulatory requirements as do larger systems, but they rarely have the resources to research all the different options available to provide safe and affordable drinking water. This is particularly true for systems that need to change treatment to comply with a new regulation, and in doing so, produce a new type of residual.

Table 1.1

Water system categories

Category

Population range

Median population*

Average flow (mgd)

Flow range (mgd)

1 25 – 100 57 0.0056 0.004 - 0.015

2 101 – 500 225 0.024 0.015 – 0.075

3 501 – 1,000 750 0.086 0.075 – 0.15

4 1,001 – 3,300 1,910 0.23 0.150 – 0.50

5 3,301 – 10,000 5,500 0.7 0.50 – 1.50

Source: Adapted from DPRA 1993 *Calculated from FRDS database 7/96


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These small systems differ from their larger counterparts in terms of ownership, resources and complexity. The intent of this document is to assist small system personnel in evaluating residuals processes in terms of complexity and regulatory requirements in a way that is meaningful to a small system. It is not meant as a guide to the selection of a new water treatment process, but it does provide the information needed to understand what is involved in the handling and disposal of the by-products of existing and new processes.

Because of the expense that may be involved with disposal of certain types of wastes that exceed regulatory limits, the most cost-effective treatment may be a compromise between treatment optimization and maintaining the characteristics of the waste stream below specified levels (Idaho DEQ 2007).

Much information on small systems and on residual treatment is readily available from the Water Research Foundation, the USEPA, AWWA, and the National Rural Water Association as well as from state regulatory agencies.

HOW TO USE THIS MANUAL

The intent of this manual is to highlight the information applicable to small systems from

existing sources and to direct users to these existing sources. It’s intended to allow the user to determine the residuals impact of treatment choices and so choose the system that makes the most sense in terms of residuals disposal and water quality. It is also meant to demonstrate that solids are much easier to dispose of than liquid residuals, and that is also a good practice to avoid the production of a material that could be considered “hazardous” or radioactive. The document is organized as follows: Chapter 1 Introduction Chapter 2 What kind of residuals do water treatment processes produce? Chapter 3 Quantities and Characteristics

Chapter 4 What are the regulations that govern the disposal and handling of these residuals?

Chapter 5 Thickening and Dewatering Chapter 6 Special Wastes Chapter 7 Landfill

Chapter 8 Land Application and Beneficial Uses Chapter 9 Sewer and Direct Discharge Chapter 10 Underground Injection Chapter 11 Summary

Appendix A is very important in the planning of any residuals project. It contains all of the State contacts in the drinking water, UIC and radiation programs.

For more information on small system issues, go to www.epa.gov

www.awwa.org www.nrwa.org

www.nesc.wvu.edu


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CHAPTER 2

WHAT KIND OF RESIDUALS ARE PRODUCED?

Water treatment processes remove contaminants from water or alter the contaminant properties in order to produce potable water. All water treatment processes that remove contaminants produce a waste by-product. That by-product may be liquid, solid, a mixture of the two, or a gaseous vapor. These water treatment plant wastes are referred to as residuals.

Small systems are looking at adding different types of treatment to meet new regulatory requirements as shown in Table 2.1. Although this manual isn’t meant to help in the decision process involved with choosing treatment technologies themselves, Table 2.2 shows the types of treatments that USEPA has indicated can be used to meet those new regulations. This chapter discusses the types of residuals produced by these treatments.

To start assessing the disposal options available for treatment residuals, a system operator

must know: � Whether the residuals produced are solids or liquids � Some information on the chemical and physical quality of the material � How much of this material is produced This chapter and the next help answer those questions.

WHAT RESIDUALS ARE PRODUCED?

Table 2.3 shows the residuals produced by the treatment processes USEPA has determined to be the Best Available Technologies (BAT) or Small System Compliance Technologies (SSCT) for regulated contaminants. BATs can be implemented by any utility for compliance, but the SSCT can only be used by utilities serving <10,000 customers. As shown in these tables, each process can produce a number of waste streams, all of which have unique handling and disposal requirements. Each type of process and the waste streams resulting from its use is briefly described in this chapter.

There are six general types of water treatment processes that produce residuals:

Common Waste Products from

Water Treatment

� Clarifier/Sedimentation

sludge � Spent filter backwash water � Spent rinse water/Cleaning

solution � Brine � Spent adsorption material � Concentrate � Gas

To find out more about strategies for compliance with regulations for small systems, go to: www.epa.gov/ogwdw/regs/swtrsms.pdf and

www.epa.gov/safewater/smallsystems.


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Table 2.1

Small system regulatory summary

Regulation Summary What systems are affected?

Microbiological (National Primary Drinking Water Regulations (NPDWR)

Coliform MCL All types and sizes

Volatile Organic Chemicals (NPDWR)

MCLs* All CWSs and NTNCWSs

Radionuclides MCLs* All types and sizes

Radon MCLs* All types and sizes

Inorganic Chemicals (NPDWR) MCLs* All CWSs and NTNCWSs; transient systems exempt except for nitrates, nitrites

Total Coliform Rule No more than 5% of samples positive for coliform; distribution system sampling

All types and sizes

Surface Water Treatment Rule 3 Log (99.9%) removal of Giardia, 4 Log (99.9%) virus inactivation filtration treatment specified

All surface water and groundwater under the direct influence of surface water

Lead and Copper Rule Distribution system action levels All CWSs and NTNCWSs

Arsenic MCLs* All CWSs and NTNCWSs

Groundwater Rule Appropriate use of disinfectants, multi-barrier approach

All systems using groundwater as source

Long Term 1 Enhanced Surface Water Treatment Rule

2 Log removal (99%) of Cryptosporidium, 0.2 NTU for

Turbidity, TOCH reductions for

precursor removal

All surface water and groundwater under the direct influence of surface water

Filter Backwash Rule Recycling filter backwash with treatment

All conventional (flocculation/coagulation/sedimenta-tion) and direct filtration systems

State 1 Disinfectants/Disinfection By-Products Rule (D/DBP)

Total Trihalomethane MCL reduced to 0.08 mg/L; 5 Haloacetic acids total of 0.060 mg/L; chlorite MCL 1.0 mg/L; bromate 0.010 mg/L MCL; maximum residual disinfectant levels set at 4.0 mg/L as Cl2 and 0.8 mg/L as ClO2.

CWSs and NTNCWSs that use a chemical disinfectant

Long Term 2 Enhanced Surface Water Rule and Stage 2 D/DBP Rules

Enacted together to balance microbial and disinfectant by-product formation; Possible lowering of current MCLs and distribution system requirements

All types and sizes

Contaminant Candidate List (CCL) Possible new MCLs All types and sizes

Source: USEPA 2003a

*For MCL information, please visit: www.epa.gov/safewater/contaminants/index.html HTotal Organic Carbon


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Table 2.2

Regulated contaminant list (partial) and possible removal technologies

Microbial Contaminants and Turbidity

Turbidity (suspended material) Filtration

Coliform Bacteria, Viruses, Cryptosporidium oocysts and Giardia cysts

Turbidity reduction by filtration as noted above followed by disinfection

Radioactivity

Beta particle and photon activity Mixed bed ion exchange, reverse osmosis

Gross Alpha Particle activity Treatment method depends on the specific radionuclide (e.g. radium, radon, or uranium)

Radium 226 and Radium 228 Cation ion exchange, reverse osmosis

Radon Activated carbon

Uranium Anion ion exchange, activated alumina, microfiltration, reverse osmosis

Health-Related Inorganic Contaminants

Antimony Microfiltration, reverse osmosis

Arsenic (+3) Reverse osmosis

Arsenic (+5) Iron based media, anion ion exchange, activated alumina, reverse osmosis

Organic Arsenic complexes Activated carbon

Asbestos Submicron filtration, reverse osmosis

Barium Cation ion exchange, reverse osmosis

Beryllium Submicron filtration and carbon, activated alumina, cation ion exchange, reverse osmosis

Cadmium Submicron filtration, cation ion exchange, reverse osmosis

Chromium (+3) Cation ion exchange, reverse osmosis

Organic Chromium Complexes Activated carbon

Copper, Nickel Cation ion exchange, reverse osmosis

Fluoride Activated alumina, reverse osmosis

Lead Cation ion exchange, submicron filtration and carbon, reverse osmosis

Mercury (+2) Cation ion exchange, submicron filtration and carbon, reverse osmosis

Mercury (HgCl3-1) Anion ion exchange, reverse osmosis

Organic Mercury Complexes Activated carbon

Nitrate and Nitrite Anion ion exchange, reverse osmosis, biological treatment

Selenium (+4) Submicron filtration and carbon, anion ion exchange, activated alumina, reverse osmosis

Selenium (+6) Anion ion exchange, activated alumina, reverse osmosis

Sulfate Anion ion exchange, activated alumina, reverse osmosis

(continued)


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Table 2.2 (Continued)

Health-Related Organic Compounds

Use activated carbon or aeration to remove the following contaminants

Adipates Benzene Carbon Tetrachloride Dibromochloropropane Dichlorobenzene (O-, m-, p-) 1,2-Dichloroethane 1,1-Dichloroethene

Cis- and trans-1,2-Dichloroethene 1,2-Dichloropropane Ethylbenzene Ethylene Dibromide Hexachlorocyclopentadiene Monochlorobenzene Styrene

Tetrachloroethylene Toluene 1,2,4-Trichlorobenzene 1,1,1-Trichloroethane 1,1,2-Trichloroethane Trichloroethylene Trihalomethanes

Use activated carbon to remove the following contaminants

Alachor Aldicarb Aldicarb Sulfone Aldicarb Sulfoxide Atrazine Benzo(a)anthracene (PAH) Benzo(a)pyrene (PAH) Benzo(b)fluoranthene (PAH) Benzo(k)fluoranthene (PAH) Butyl benzyl phthlate (PAH) Carbofuran

Chlordane Chrysene (PAH) 2,4-D Dalapon Di (2-ethylhexyl) adipate Dibenz (a,h)anthracene (PAH) Glyphosate Heptachlor Epoxide Hexachlorobenzene Indeno (1,2,3-c,d) Pyrene (PAH)

Lindane Methoxychlor Oxamyl Pentachlorophenol Picloram Polychlorinated Biphenyls Simazine 2,3,7,8-TCDD (dioxin) Toxaphene 2,4,5-TP (Silvex)

Source: USEPA 2003a

Table 2.3

Residual type by treatment technology

Types of residuals

Solid Liquid

Treatment Spent

resins/media Spent

membranes Sludge Brine

Spent backwash

water Rinse water

Acid neutralization

water Concentrate

Coagulation/ Filtration Τ Τ Τ

Lime softening Τ Τ Τ

Ion exchange Τ Τ Τ Τ

Adsorption Τ Τ Τ Τ

Membranes Τ Τ Τ

Aeration ! Gaseous release

Reverse osmosis Τ Τ

Iron based media Τ Τ

Biological treatment Τ

Green sand filtration Τ Τ Τ

Activated alumina Τ Τ Τ Τ Τ Source: Adapted from USEPA 2005a


7

� Coagulation/filtration � Lime softening � Ion exchange � Adsorption � Membranes � Aeration The first general category of residuals is produced at those plants that coagulate and

oxidize a surface water to remove particles (both organic and inorganic) and dissolved contaminants such as color, organic carbon, iron, manganese, and occasionally trace metals. These coagulation plants produce two major residuals, sedimentation (or clarifier) sludge and spent filter backwash water (SFBW). They can also produce spent filtration media, although this is produced only once in several years. The second type of treatment plants are those that practice softening for the removal of calcium and magnesium by using lime or sodium hydroxide addition. These plants may also remove trace metals, radioactivity, and particles if a surface water is being treated. These plants also produce a clarifier sludge and spent filter backwash water, and spent filtration media. Ion exchange processes as their name implies are used to remove cation or anion contaminants such as calcium and magnesium, arsenic, nitrate and barium. These processes produce a brine residual as well as spent rinse water, spent media and often, spent filter backwash water. Adsorption processes can produce residuals similar to those produced by ion exchange if the material is regenerated. Many adsorption processes can use “throw away media” such that the residual produced is the spent adsorption material. Adsorption media may also need to be backwashed and so a spent backwash water is produced. The fifth general category of treatment is when membranes are used to remove particles or dissolved solids. In this case a concentrate is produced that consists of concentrated levels of the raw water contaminants that the membrane has rejected as well as any additives that may have been used prior to membrane treatment. Cleaning solutions and the spent membranes are also considered to be residuals. Finally, gaseous residuals are produced by air stripping processes that release vapor to the atmosphere. These releases that can be of concern are primarily volatile organic compounds and radon.

COAGULATION WASTE STREAMS

Coagulation of surface waters is by far the most commonly used water treatment technology. It is historically used to remove turbidity and reduce biological activity of the source water. Recently, it has been shown to be effective at removing raw water arsenic. Figure 2.1 shows a schematic of a conventional coagulation treatment process showing the typical waste products. Some water plants also have a pre-sedimentation step. This is generally used only when the raw water source is high in settleable solids.

Smaller systems often utilize package filtration plants that incorporate coagulation/sedimentation with filtration. The residuals produced in these package plants are the same as discussed here.


8

Mechanical/Non-Mechanical Dewatering

SFBW Clarifier

Thickener/Lagoon

RecycleSewerStream Discharge


Liquid Stream

SFBW Clarified Stream

SFBW Settled Solids

Spent Filter Backwash Water

M M M

M

Raw

Rapid Mix Flocculation Basin

Sedimentation Basin Filters

Residuals Treatment Processes often Combined

Filtered Water

Equalization Basin

ThickenedThickener Supernatant

Sedimentation Basin Sludge

Secondary Residual Streams

Process Residuals Streams

Dewatering Residuals Streams

Dewatered Solidsor

Sludge Cake

ThickenerSewerOther


Thickened

Sludge

Source: Cornwell 2006

Figure 2.1 Major residual streams commonly generated by coagulation water treatment

plants

The coagulation process itself generates most of the waste solids. Generally a metal salt (aluminum or iron) is added as the primary coagulant. In addition to the coagulant other solids producing chemicals such as powdered activated carbon, polymer, clay, lime, or activated silica may be used. These added chemicals will produce waste solids. They are usually removed, along with the solids in the raw water, in a sedimentation tank or clarifier. These residuals are referred to as sedimentation or clarifier sludge. They are more specifically referred to by the type of coagulant used. For example, alum sludge is the residual produced from the use of an aluminum based coagulant and iron sludge is the residual produced by the use of an iron based coagulant. When dissolved air flotation is used as the clarification step, the residuals are referred to as float. In areas with very good raw water quality, the clarification step is occasionally omitted and the solids are removed by filtration only. This process, commonly known as direct filtration, is usually used for water with low turbidity and is one that requires low levels of coagulant. It is also used in arsenic removal coagulation filtration processes.

The residuals can be further treated on site resulting in additional residuals streams. A thickener treating clarifier sludge or clarifier sludge plus SFBW produces thickened sludge (which could be thickened alum or iron sludge) and thickener supernatant. A thickener that only treats SFBW will produce SFBW settled solids. A dewatering device will produce a sludge cake (also called dewatered solids) as well as a liquid stream. The liquid stream is referred to by the type of dewatering used such as filtrate, decant, centrate, and pressate.


9

The second major residual produced by coagulation/filtration is from the batch process of backwashing the filters, spent filter backwash water (SFBW). This waste stream is produced at very high flow rates for short periods of time. Another waste product that is occasionally produced in a coagulation-based plant is spent filtration media and spent granular activated carbon (GAC). GAC is sometimes used in the filters or post-filtration. When its use is for taste and odor removal, the carbon is disposed of after its capacity is exhausted. When its use is for continuous low-level organics removal it is often returned to the vendor for regeneration.

SOFTENING WASTE STREAMS

Wastes produced by softening plants represent the second major waste product produced

by the water industry. Fortunately, these wastes are generally more easily dewatered than are coagulant wastes, although the presence of some trace inorganics can make their proper disposal difficult. There are many variations of the softening process. Chemical addition, flow processes, and the subsequent waste quantities and characteristics are all dependent on raw water hardness and alkalinity, and the desired finished water quality.

Softening is accomplished either by chemical precipitation of the calcium and magnesium or by the use of ion exchange resins. The former, traditionally called lime/soda ash softening is by far the most widely used softening process by larger facilities and ion exchange is common for small systems and as a home softener. In the lime method, lime is added for the removal of carbonate hardness, supplemented with the use of soda ash for non-carbonate hardness removal if required. From the standpoint of sludge economics, it is desirable to leave as much magnesium hardness in the water as considered acceptable. The less magnesium in the sludge, the easier it is to dewater.

Figure 2.2 is a simplified softening plant schematic. Several variations and complications of Figure 2.2 are used to obtain the desired water quality and minimize costs. In softening plants there are usually two waste streams produced: the lime sludge from the clarifier and the spent filter backwash water. Some plants will add a polymer or metal salt to aid in the removal of fine precipitates or color or turbidity present in the original water. From a sludge viewpoint, the addition of metal salts should be held to a minimum as the presence of metal hydroxides could significantly increase sludge treatment costs. The use of polymers and slurry recirculation can help minimize the use of these coagulants. As with coagulation plants, spent filter backwash water is produced at high flow rates for short periods of time.

Source: Cornwell 2006 Figure 2.2 Waste producing processes in softening plants

RawWater

M M M M

ChemicalAdditions

OxidantLime

Soda AshCoagulant

Coagulant AidCoagulant

Coagulant AidCoagulant CO2

OxidantFilter Aid

FluorideCorrosionControlOxidant

Spent FilterBackwash Water

Lime SludgeSoftening Residual Streams

Rapid Mix Reaction Zone

Clarifier

Recarbonation

Filtration


10

ION EXCHANGE AND MEDIA ADSORPTION RESIDUALS

Removal of trace inorganic substances such as arsenic, barium, cadmium, chromium, fluoride, lead, nitrate, selenium, silver, radium and uranium by ion exchange (IX) or adsorption is becoming widely used by small systems. Ion exchange (IX) involves the selective removal of charged inorganic species from water using an ion-specific resin. Removal of hardness by IX has been used for many years by small systems. Resins can be categorized as anion exchange or cation exchange resins. Anion exchange resins selectively remove anionic species such as nitrate (NO3

-) and fluoride (F-). Anion exchange resins are often regenerated with sodium hydroxide or sodium chloride solutions, which replace the anions removed from the water with hydroxide (OH-) or chloride (Cl-) ions, respectively. Cation exchange resins are used to remove undesired cations from water and exchange them for protons (H+), sodium ions (Na+) or potassium ions (K+). Anion exchange is a USEPA identified best available technology (BAT) for arsenic removal. Arsenic ions are exchanged for chloride ions.

Ion exchange has also been used historically to soften water. In water softening by ion exchange the water containing the hardness is passed through a column containing the ion exchange material. The hardness in the water exchanges with an ion (usually sodium) from the ion exchange resin.

When used for softening the exchange results in essentially 100 percent removal of the hardness from the water until the exchange capacity of the ion exchange material is reached. When the ion exchange resin becomes saturated, “breakthrough” occurs because the hardness is no longer removed. At this point the ion exchange material is regenerated. During regeneration, the hardness is removed from the material by passing water containing a large amount of sodium chloride (NaCl) through the column. The process is shown in Figure 2.3. This spent regenerant or brine is the residual stream that requires disposal. It contains the excess or left over NaCl, and the ions removed. Ocean brine disposal is sometimes practiced as well as discharge to municipal wastewater systems, or to receiving streams. Two additional waste streams are also produced in conjunction with ion exchange. Prior to the use of the regenerant, the column is usually backwashed in an upflow mode to remove any suspended material. After regeneration the column is rinsed, which will produce a waste stream also high in dissolved solids. Adsorption, particularly with a media created specifically for a particular contaminant removal is widely used by small systems because of the ease of operation. For example, many iron based media developed specifically to remove arsenic from groundwaters are now being used by small systems. The residuals produced by adsorption are the “spent media” as well as the rinse or spent filter backwash water. Adsorption media can be regenerated like an ion exchange media or the spent media can be replaced without regeneration. Operationally, adsorption is very similar to ion exchange and the residuals produced are very similar when the media is regenerated. One notable difference, however is that certain media have been developed for specific contaminants and cannot be regenerated, or are not regenerated. This avoids the production of a waste regenerate solution, but adds the operating cost of media disposal and replacement. In this case, the media is disposed of after break-through occurs.


11

Source: SAIC 2000

Figure 2.3 Schematic of ion exchange process with upflow regeneration

MEMBRANE AND REVERSE OSMOSIS RESIDUALS

Membranes can be used to remove a variety of contaminants. The size of contaminant removed depends upon the type of membrane selected and its associated pore size. As membrane systems are increasingly used for water utility applications, the management of their residuals has become a growing challenge. Membrane technology uses a driving force (e.g., electrical, pressure/vacuum, etc.) to separate contaminants from the water. Pressure-driven membranes include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). Electrically-driven membranes include electrodialysis (ED) and its variant electrodialysis reversal (EDR). Whereas MF and UF membranes are designed for particle removal and use low-pressure, NF, RO, and ED/EDR are designed for desalination and softening. MF and UF processes are low pressure membranes that primarily remove particles. They are used commonly by small systems to treat relatively clean groundwaters, springs and streams for pathogen removal. They are also used in the coagulation microfiltration process for arsenic removal. The particles build up on the membranes and are backwashed off to clean the membrane. This membrane backwash residual contains the particles that were removed from the source water. Occasionally a coagulant or PAC is added to the raw water prior to the membrane and that will also be in the membrane backwash. These residuals are referred to as membrane backwash.

High pressure membranes such as RO and NF primarily remove dissolved ions. These membranes produce a fairly continuous residual that contains the concentrated ions that the membrane rejects. The waste streams are referred to as concentrate and occasionally brine.

Raw Water

SourceIon Exchange Column

Regeneration Streams

Spent Regenerant

(Brine)

[To Waste Disposal]

Ion Exchange

Resin

Product/Treated

Water

Spent Backwash/Rinse

Regenerant

Backwash/Rinse

Pre-Filter

Raw Water

SourceIon Exchange Column

Regeneration Streams

Spent Regenerant

(Brine)

[To Waste Disposal]

Spent Regenerant

(Brine)

[To Waste Disposal]

Ion Exchange

Resin

Ion Exchange

Resin

Product/Treated

Water

Product/Treated

Water

Spent Backwash/RinseSpent Backwash/Rinse

RegenerantRegenerant

Backwash/RinseBackwash/Rinse

Pre-FilterPre-Filter


12

Cleaning solutions are used in membrane operations. Those residuals reflect the chemicals used in the cleaning process, so the resulting chemical cleaning waste includes some remaining active chemical ingredient, as well as dissolved organic materials, suspended solids, and salts from chemical reactions between the chemicals and foulants (AWWA 2003). Chlorine residuals in concentrates and cleaning wastes may range from 1 mg/L to 1,000 mg/L as Cl2, and pH may be acidic (pH<6) or basic (pH>9) depending on the chemicals used. When surfactants are employed they may cause foaming when the spent cleaning solution is discharged.

IRON AND MANGANESE OXIDATIONS RESIDUALS

Iron and manganese are often removed by oxidation followed by filtration. Oxidation is achieved through the addition of air, chlorine, or permanganate followed by granular media filtration. Other inorganic contaminants, most notably arsenic (as arsenate) are also removed by this process. The insoluble form of the contaminant is deposited on the media. When the filters are backwashed, SFBW is generated and this liquid plus suspended solids waste contains the contaminants. Greensand filtration, with the addition of potassium permanganate also removes a variety of contaminants including iron, manganese and in some cases arsenic. Again, the waste generated by this process is through backwashing of the filter, spent filter backwash water (SFBW).


13

CHAPTER 3

QUANTITIES AND CHARACTERISTICS

The amount of material generated by a water treatment process is an important piece of information needed in order to plan for its treatment and disposal. In this chapter, methods to estimate quantities of different types of residuals will be described. Characteristics of the material will also be discussed.

COAGULANT SOLIDS

Coagulant solids are produced from coagulation/filtration, softening and some iron and

manganese removal processes (oxidation/filtration.) The quantity of solid/liquid wastes (which are commonly referred to as sludge) generated from water treatment plants depends upon the raw water quality, the type and dosage of chemicals used, and the efficiency of the treatment process. One of the most difficult tasks facing the utility or engineer in planning and designing a residuals treatment process is determining the amount of waste to be handled. The waste quantity is usually determined as an annual average for a given design year and is a function of flow projections. As important as average production values is information on seasonal and monthly variations. It is not unusual for order of magnitude differences in sludge production to exist for different months of the year.

There are three methods used to determine sludge quantities. None are completely accurate. Those methods are: calculations, coagulant mass balance analysis, and field determination. Here, an explanation of how to use calculations to estimate the quantity of coagulant sludge will be shown, as this is the most useful method for small systems. Further information on mass balance calculations and field measurements can be found in Cornwell, 2006. The amount of alum (or iron) sludge generated can be calculated fairly closely by considering the reactions of alum or iron in the coagulation process. When alum is added to water as aluminum sulfate, the reaction results in the production of a solid species of aluminum hydroxide.

The resulting aluminum hydroxide species (or coagulant sludge) is such that 1 mg/L of alum as dry weight product added to water will produce approximately 0.44 mg/L of inorganic aluminum solids. Suspended solids present in the raw water produce an equivalent weight of sludge solids since they are non-reactive. It can be assumed that other additives such as polymer and powdered activated carbon produce sludge on a one to one basis. The amount of sludge produced in an alum coagulation plant for the removal of turbidity is then:

S = 8.34 Q (0.44 Al + SS + A) (3.1)

Sludge volumes from sedimentation basins tend to be 0.1 to 3 percent of the raw water flow with one national survey finding an

average of 0.6 percent. (AWWA 1999)


14

where S = sludge produced (lb/day dry weight) Q = plant flow (mgd) Al = alum dose as 17-percent Al2O3 (mg/L) (MW = 594) SS = raw water suspended solids (mg/L)

A = additional chemicals added such as polymer, clay or activated carbon (mg/L) If iron is used as the coagulant the solids production equation becomes: S = 8.34 Q (2.9 Fe + SS + A) (3.2)

Where the iron dose (Fe) is expressed as mg/L of Fe3+ added or produced via Fe2+

oxidation (note that significant Fe2+ in the raw water will also produce sludge at a factor of 2.9 if it is oxidized). Generally, a coagulating equivalent of iron produces about 20 to 25 percent more dry weight sludge than alum. When iron is purchased as ferric chloride (FeCl3), the coagulant dose is usually reported as equivalent dry weight of chemical without waters of hydration (although this should be confirmed with the manufacturer). This results in the production of 1.0 mg of solids produced for each milligram of ferric chloride (FeCl3) added. The equation to use to estimate the production of solids produced by using ferric chloride is then: S = 8.34 Q (FeCl3 + SS+A) (3.3) The problem in using these equations is that most plants routinely analyze raw water turbidity, and not suspended solids concentrations. Unfortunately there isn’t a one-to-one relationship between the two measurements. Instead, they’re related by a “b” factor:

SS (mg/L) = b • Tu (3.4) The value of b for low color, turbidity removal plants can vary from 0.7 to 2.2. It may vary seasonally for the same raw water supply. A utility can, therefore, either continually measure suspended solids, or it may be possible to develop a site-specific correlation between measured turbidity (NTU) and suspended solids. Very often a value of 1.5 is used if there are not data available. Another complication exists for raw water sources that contain a significant amount of color. Color, perhaps indicated by TOC, can be a large contributor to the sludge production. Values of b for colored raw waters can be as high as 20, but unless turbidity and color vary together, a correlation between SS and NTU will not exist. Figures 3.1, 3.2, 3.3 and 3.4 can be used to estimate the quantity of coagulant sludge that would be produced by coagulation using either alum or ferric chloride. For these graphs, the equations discussed above were used and it was assumed that “b” is equal to 1.5, although as noted above this will not always be the case. Figure 3.1, using equation (3.3) above graphically shows the amount of dry solids that could be produced per million gallons of water for different turbidity values of the raw water and different alum doses. From this graph, for example it can be estimated that a groundwater, having no turbidity and using 10 mg/L of alum in coagulation, would produce about 36 pounds of dry solids per million gallons of water produced. For a system that has a raw water turbidity of 30 and uses 40 mg/L of alum, it can be seen that over 500 lbs of dry solids would be produced.


15

0

100

200

300

400

500

600

700

800

0 10 20 30 40 50 60 70 80 90 100

Alum Dose (mg/L)

So

lid

s P

rod

uce

d (

dry

lb

/MG

)

30 ntu

25 ntu

20 ntu

15 ntu

10 ntu

5 ntu

0 ntu

Figure 3.1 Quantity of dry alum solids produced under different conditions

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

0 10 20 30 40 50 60 70 80 90 100

Alum Dose (mg/L)

Slu

dg

e V

olu

me

Pro

du

ced

@ 0

.5%

so

lid

s (g

al/

MG

)

30 ntu

25 ntu

20 ntu

15 ntu

10 ntu

5 ntu

0 ntu

Figure 3.2 Volume of alum sludge produced under different conditions


16

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

0 10 20 30 40 50 60 70 80 90 100

FeCl3 Dose (mg/L)

So

lid

s P

rod

uce

d (

dry

lb

/MG

)

30 ntu

25 ntu

20 ntu

15 ntu

10 ntu

5 ntu

0 ntu

Figure 3.3. Quantity of dry ferric solids produced under different conditions

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

30000

0 10 20 30 40 50 60 70 80 90 100

FeCl3 Dose (mg/L)

Slu

dg

e V

olu

me

Pro

du

ced

@ 0

.5%

so

lid

s (g

al/

MG

)

30 ntu

25 ntu

20 ntu

15 ntu

10 ntu

5 ntu

0 ntu

Figure 3.4 Volume of ferric sludge produced under different conditions


17

Figure 3.2 uses this same information to estimate the volume of sludge produced for planning purposes. Typical coagulant sludge from the sedimentation basin or clarifier ranges from 0.2 to 3 percent solids concentration, with 0.5 percent common for many systems. Using a concentration of 0.5 percent, Figure 3.2 graphically shows how many gallons of sludge per million gallons of water treated coagulation produces. For a system with no raw water turbidity and feeding 10 mg/L of alum, 860 gallons of 0.5 percent sludge would be produced per million gallons, while 12,500 gallons of sludge per million gallons of water would be produced if the raw water had a turbidity of 30 and 40 mg/L of alum was fed.

Figures 3.3 and 3.4 show the same type of information – quantity (in dry weight and in gallons) of sludge produced per million gallons of water produced at different turbidities and coagulant doses using equation 3.3. For these two graphs, the coagulant is ferric chloride.

Note that these plots give the quantities of sludge as “per million gallons of water produced.” These values can be useful for small and very small systems as well by dividing the quantity of sludge produced per MG by 1,000,000 to get a “per gallon” value, and then multiplying by the number of gallons produced. Some example values for small systems are shown in Table 3.1.

Table 3.1

Examples of estimated sludge production

Flow (mgd)

Population (est.)

Turbidity (NTU)

Alum dose (mg/L)

Sludge produced at 0.5 percent solids

1 (from graph) 7,000 30 40 12,500 gallons

0.70 5,500 30 40 8,764 gallons

0.23 1,910 30 40 2,880 gallons

0.086 750 30 40 1,077 gallons

0.024 225 30 40 300 gallons

0.0056 57 30 40 70 gallons


18

Figure 3.5 Example of annual sludge production variation by month

These equations and graphs are useful in estimating the amount of sludge that will be

produced by coagulation. For planning a disposal option, it’s also important to look at seasonal variations in sludge production. Over a year, sludge production will vary significantly, not only because of a flow variation but because of turbidity and coagulant dose changes. For design of drying beds or for planning for direct discharge, for example, it is important to not only know the average production but also peak production. Figure 3.5 shows how significantly these production numbers can vary.

LIME RESIDUALS A general equation has also been developed for the softening process with or without the use of alum, iron, or polymer:

S = 8.34 Q (2 CaCH + 2.6 MgCH + CaNCH + 1.6 MgNCH + CO2 + 0.44 Al + 2.9 Fe + SS + A) (3.5) where S = sludge production (lb/day) CaCH = calcium carbonate hardness removed as CaCO3 (mg/L) MgCH = magnesium carbonate hardness removed as CaCO3 (mg/L) Fe = iron dose as Fe (mg/L) Al = alum dose as 17.1 percent Al2O3 (mg/L) Q = plant flow (mgd) SS = raw water suspended solids (mg/L) A = other additives (mg/L) CaNCH = noncarbonate calcium hardness removed as CaCO3 (mg/L)

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000Solids Production (lb/day)

1 2 3 4 5 6 7 8 9 10 11 12

Month


19

MgNCH = noncarbonate magnesium hardness removed as CaCO2 (mg/L) CO2 = carbon dioxide removed by lime addition, as CaCO3 (mg/L)

The above equation will allow estimation of the dry weight of sludge produced. Impurities associated with lime can be added to this equation.

The amount of sludge produced by softening can vary significantly because of a number of variables, so it’s difficult to establish “typical” production numbers. The amount depends not only on plant flow and raw water hardness, but also on the amount of hardness removed, the type of hardness (calcium vs. magnesium hardness, carbonate vs. noncarbonated) and the dosages of lime and coagulant used. The solids content of softening sludges can range significantly, and the volumes are significantly higher than those from coagulation processes. For utilities considering softening, it is important to gather the data needed for equation 3.5 and use the equation to estimate the volume of sludge produced for their unique raw water quality and water quality goals.

This equation can also be used to set or modify the water quality goal of finished water hardness. Factoring in the amount of residuals produced and the cost of disposal at different levels of hardness removed can help set a water quality goal that is economically achievable by the system. Using this equation before the process is put in place can help a system determine a realistic total cost of the system.

MANGANESE AND IRON REMOVAL RESIDUALS

Wastes produced from treatment designed solely for iron or manganese removal are similar in nature to iron coagulant sludge. Typically, these processes consist of aeration for oxidation of the iron and manganese, followed by a detention time for reaction and then filtration.

The dry weight of sludge produced is a direct function of iron removed and can be predicted using equation 3.2.

Every mg/L of Fe removed produces 2.9 mg of dry weight solids. Every mg/L of manganese removed produces 1.6 mg of dry weight solids. The waste stream is produced during the backwashing of the filters if sedimentation is not employed. The flows and solids concentrations are very similar to SFBW.

Data from Cornwell (1987) showed that volumes of backwash water produced from six iron and manganese removal plants in operation ranged from 3 to 38 gallons of backwash water produced for each 1,000 gallons of raw water filtered. Detention time after aeration does not seem to influence the amount of backwash water produced, nor do the raw water iron or manganese concentrations. Instead, operational practices dictate the volume of waste produced.

ION EXCHANGE AND MEDIA ADSORPTION RESIDUALS

Ion exchange produces a liquid residual as a result of the regeneration process. The regenerant is typically high in sodium chloride, and after backwashing the media for regeneration, the liquid residual contains the regenerant (high salt content), spent filter backwash water, contaminants removed from the raw water, and rinse water. The volume of this material (regenerant plus rinse plus backwash) is typically in the range of 20 to 80 gallons per 1,000 gallons of raw water treated depending on the frequency of regeneration. Depending on the raw water quality, the volume of water used and the target contaminant, ion exchange regeneration


20

may be needed frequently. This relationship is also valid for arsenic removal plants that use coagulation-filtration (CF) or coagulation-microfiltration (CMF). Those plants either add iron or use the iron in the raw water to remove the arsenic. The amount of dry weight residual produced can be predicted from equation 3.2 by using the sum of the iron added and the iron present in the raw water. If manganese is also removed that residual should be added to the production, although the manganese contribution may be rather minor. Adsorption processes can be used for a number of purposes, and the wastes produced are dependant upon the application. Granular activated carbon (GAC) has been used for many years to remove organic compounds such as disinfection by-product precursors (TOC), taste and odors, and synthetic organic compounds (SOCs). A SFBW can be produced when the media is backwashed. Generally for small systems, the GAC is not regenerated by the utility when it is exhausted but rather it is returned to the vendor or disposed of in a landfill as a solid waste. When GAC is used to remove specific organic contaminants sometimes found in groundwater sources, it is possible for the GAC to become a hazardous waste by failing the TCLP test.

Activated alumina (AA) is an inorganic sorbent that is used to remove fluoride and arsenic and its adsorption capacity is pH dependent. In the activated alumina process, influent water is sent through a column packed with activated alumina where the arsenic or fluoride ions are adsorbed onto the alumina. In this way, the activated alumina process is similar to the anion exchange process. Exhausted activated alumina may be regenerated on-site, much like ion exchange resins, or it may be used to exhaustion and replaced with new media. Iron oxide media is a common method for the removal of arsenic. Depending upon the raw water characteristics, the media may occasionally need to be backwashed. The backwash water is high in arsenic and difficult to dispose of. Therefore, most systems will try to avoid a backwash step. One way to avoid backwashing is to use a prefiltration step. This approach is described in the AwwaRF Report by Min et al. 2005.

Iron media used for arsenic removal can also be regenerated although they are designed to be thrown away. However, the waste product is highly undesirable due to the high level arsenic present and the preferred method is to return the media to the vendor when it is exhausted.

For more information on contaminant adsorption of GAC see The Hazardous Potential of Activated Carbons Used

in Water Treatment (McTigue et al.1994)

For more information on avoiding and treating backwash from iron coated media see Innovative Alternatives to Minimize Arsenic, Perchlorate and Nitrate Residuals

(Min et al. 2005)


21

0

200

400

600

800

1000

1200

1400

1600

0 200 400 600 800 1000

Influent Flow (gpm)

Media Bed Volume (ft3)

3 minute BCT 5 minute BCT

7 minute BCT 10 minute BCT

Figure 3.6 Estimated quantity of adsorption media required at different flows and contact

times

For iron adsorption media for arsenic removal, the amount of media that needs to be returned or disposed of is a function of the contact or detention time, called the empty bed contact time (EBCT). The vendor can supply this value but it is generally around five minutes. Therefore, the volume of media present is about 66 ft3 for every 100 gpm. Figure 3.6 allows for the estimation of the amount of media present for a given design flow and contact time. It does not include any redundant vessels that may be used. The spent regenerant and SFBW will contain high levels of salt (for ion exchange), and carry contaminants that are released from the media. Often, high levels of arsenic and other ions are found in the liquid, either in their dissolved form or associated with particles. Particulate matter in SFBW can contain high levels of arsenic, for example and so the SFBW would require proper disposal.

SPENT FILTER BACKWASH WATER

All water treatment processes that use granular media filters (e.g., conventional filtration,

softening, iron removal, arsenic removal and direct filtration) generate spent filter backwash water during media cleaning operations. Untreated spent filter backwash water (SFBW) consists of the washwater and solids carried directly off the top of a filter during backwash operations. This SFBW may or may not undergo any treatment before being recycled to the water treatment process or discharged to a stream or wastewater treatment plant.

The volume of spent filter backwash water generated at a water treatment plant is dependent on a number of factors including backwash duration, washwater rate, backwashing


22

frequency (filter run length), and number of filters. Filters are typically backwashed every one to four days, depending on treatment effectiveness, water quality, and season. Many facilities stagger backwashes, so that even when filter run lengths are long, one or more filters are backwashed on a daily basis. Backwash duration and rate also vary with treatment process, water quality, and season.

The volume of SFBW created by a treatment process can be estimated as follows: area of filter (ft2) x backwash rate (gpm/ft2) x duration of bw = backwash volume/backwash

This is the amount of SFBW created every time one filter is washed. The total quantity of backwash created by a process depends on the number of filters and the frequency of backwashing. In general, this volume can range anywhere from 3 percent to 10 percent of the total water produced by the treatment facility. This SFBW is typically discharged with or without solids removal to a receiving stream or sewer, or recycled back to the beginning of the process. It is often stored for a period of time to reduce the instantaneous discharge or recycle.

MEMBRANE RESIDUALS

All membrane processes, including ultrafiltration (UF), microfiltration (MF),

nanofiltration (NF), reverse osmosis (RO), and ED/EDR produce two types of residuals – a concentrate (or brine) and a waste stream from the cleaning solution used in maintenance. Very often UF and MF residuals are referred to as membrane backwash water. Also, ED/EDR systems produce a specialized waste stream of limited flow called “electrode waste” that contains significant levels of hydrogen and chlorine gas. These gases are typically stripped from the electrode waste stream using a degasifier. ED/EDR systems, however, are not practical for small systems at this time (AWWA 2003).

For UF and MF membranes, recovery is the ratio of water produced (i.e., feed flow minus water used for backwash) to feed flow and can range from 85 to 98 percent, thereby concentrating solids 7 to 50 times, respectively. Backwash flow rates typically represent greater than 95 percent of the total volume of residuals produced (the remaining portion comes from chemical cleaning procedures).

Cleaning solution volumes will be two to three times the volume normally present in the membrane modules and piping (one volume for the actual cleaning solution, and one or two additional volumes to rinse the solution), or for immersed systems, equal to the tank volume (AWWA 2003). Chemical cleaning is performed far less frequently than backwashing and so contributes less than five percent in the generated residuals volume. Membrane modules may be shipped to the plant preserved in specialty solutions, such as glycerin, which are typically discharged to the sewer. In absence of a sewer connection, these wastes need to be collected and hauled to an appropriate disposal site (AWWA 2003). The volume of reject water, or concentrate, from RO and NF membranes can vary greatly depending upon the total dissolved solids (TDS) in the feed water. Treating seawater or brine well water can result in recoveries of only 50 percent, so half of the feed water is a concentrate waste and half in a finished product. When RO and NF are used to remove specific contaminants from low TDS waters, the recoveries can be much higher, 85 to 98 percent, with the remaining 2 to 15 percent being the concentrate waste.


23

SPENT GAC AND FILTRATION MEDIA

Spent granular activated carbon (GAC) wastes are essentially equal in weight to the exhausted carbon. This carbon may either be in the filters themselves or in a separate chamber following filtration. The quantity of GAC that requires disposal will be determined by the water quality goal of the treatment process. Figure 3.6 can be used to estimate the quantity of GAC used to treat a water quality goal, and so the amount of GAC that will eventually need disposal.

The chemical characteristics of this spent media will be a function of the raw water quality and of the length of time the media has been in place. GAC is very effective in adsorbing chemicals from water. GAC that has been in place as a filtration media has been shown to contain high levels of contaminants and could fail USEPA’s test for toxicity - the TCLP. This test is described in detail in Chapter 4. GAC and some filtration media can also adsorb radionuclides that are present in the raw water.

PRECOAT FILTRATION RESIDUALS

In precoat filtration (such as diatomaceous earth filtration) the raw water containing the turbidity to be removed is passed through a uniform layer of filtering media that has been deposited (precoated) on a septum. Most plants using precoat filtration will have a raw water turbidity of less than 10 NTU. The amount of precoat material used will generally be in the range of 0.1 to 0.2 lb/ft2 of filter area. The body feed tare can vary between 1 to 10 mg/L of body feed per 1 mg/L raw water suspended solids. The waste stream from the precoat filtration process will contain the turbidity removed from the raw water, the precoat material and the body feed. The more body feed used, the longer the filter runs and hence the less precoat media used per gallon of water processed.

In general, the precoat plant will produce waste according to the following equation:

( ) ( )( )

++= SS

TFR

7566PCSSBFRQ34.8S (3.6)

where S = sludge production (lb/day)

Q = plant flow (mgd) BFR = body feed ratio SS = raw water suspended solids, mg/L PC = precoat application rate (lb/ft2 of filter) FR = filtration rate (gpm/ft2) T = filter run length (hr)

SLOW SAND FILTRATION RESIDUALS

Slow sand filtration is again becoming a popular method of filtration. Generally it is used

by smaller communities that treat a low turbidity, relatively clean raw water source. During the filtration process a black organic detritus (commonly called a schmutzdecke) forms in the top layer of sand. When the head loss through a slow sand filter exceeds the allowable level the sand bed must be scraped. The scraping operation generally involves lowering the water level in the


24

filter sufficiently to allow removal of a layer of sand and the schmutzdecke. During each cleaning roughly 0.2 in. of sand is removed from the top of the filter, producing 28-in3 of waste/per filter. The sand could be cleaned and re-used but it is generally disposed of at a landfill. The sand will most likely be nonhazardous, but the landfill may require that a TCLP test be performed to verify this.

RESIDUALS CHARACTERISTICS

Physical Properties

The physical properties of WTP residuals affect the ultimate requirements for managing the waste stream or solid. The most important initial characteristic is whether the residual is predominately a liquid, that is essentially water containing solid particles, or whether the residual is essentially a solid or semi-solid material. A residual material is considered to be a solid if it passes the Paint Filter Liquids Test (PFLT) as described by USEPA Test Method 9095B (USEPA 1998a).

This initial classification is important, since it determines which methods can be considered for ultimate disposal of the material. Figures 3.7 and 3.8 show decision trees for residuals disposal, based on whether the material is a solid or a liquid.

Paint Filter Liquids Test: A measured sample is placed on filter paper, suspended in a funnel, and if no liquid passes through the paper in five minutes, the material is classified as a solid. This method (9095B) can be viewed online at www.epa/epaoswer/ hazwaste/test/main.htm.


25

Sewer available?

Tracts of forest or

agricultural

land adjacent?

Receiving stream

available?

Recycle to head of

treatment?

Arsenic/nitrate/radionuclides present in raw water?



YES YES YES YES

YESNO YESNO YESNO

See Equalization Section

Solids Removal?

YES NO

Can't produce liquid

residual.

See Special Waste Chapter

See Sewer and Direct Discharge Chapter


See Solids Flow Diagram


NO NO NO NO

See Thickening

and Dewatering Chapter

See Sewer and Direct Discharge Chapter

solids

See Land Application Chapter

liquid

Figure 3.7 Decision tree for the disposal of liquid (non-solid) residuals

Liquid residuals can include sedimentation basin sludge, spent filter backwash water,

brine concentrate, reject water, acid waste, and rinse water.


26

Landfill access?

Land application on

or off site?



YES

YESNO


See Landfill Chapter


NO

See Land Application Chapter

Return to vendor?

YES

YESNO

NO

Figure 3.8 Decision tree for the disposal of solids residuals

Solid residuals can include sludge, spent filter media, and exhausted resins.

Characteristics of Predominately Liquid Sludge

Physical properties of predominately liquid residuals that contain solids are used to define the ease of solid separation from the water. The characteristic tests are useful for comparing different treatment or conditioning techniques on a laboratory scale to predict full scale performance. It is sometime useful to conduct tests on predominantly liquid residuals to determine how quickly they can be dewatered, and also to evaluate the affect of chemical additions, such as polymers. Typical tests that are done include:


27

� CST (Capillary suction time) � TTF (Time to filter) � Specific Resistance � Particle Distribution

More information on these test methods are found in Cornwell (2006).

Characteristics of Predominately Solid Sludge

Physical characteristic tests on solid or semi-solid residuals are useful for understanding handling and compaction for the material. Tests for characterization of more solid samples – those above the liquid limit – are generally done to evaluate compaction and shear. A compaction test finds the optimal density which is necessary for predicting the volume of residuals that require disposal. The shear tests relate to the slope stability and ability to carry the load of earthmoving equipment, etc. If this type of information is required, analytical methods and a discussion of the type of data obtained from these tests is contained in Cornwell (2006). For planning purposes a dewatered residual will have a density of around 65 lb/ft3. Therefore, the volume of residual that needs to be trucked or disposed of can be estimated by: Dry Weight Produced/(65 x % solids) = ft3 (3.7) So for example, a utility producing 500 lb/day of sludge that is dewatered to 20 percent solids concentration would need to haul and dispose of:

500/(65 x 0.2) = 38 ft3/day

Chemical Characteristics

Each residual produced by water treatment will have unique chemical characteristics.

The characteristics will depend on: � Source water quality � Chemicals (oxidants, polymers, coagulants, corrosion inhibitors) added � Media used Chemical characterization of residual material is important in determining if a particular

disposal option can be used for the material. Chapter 4 describes the characteristics and limits of certain parameters that regulations have mandated. Chapters 7, 8, 9, and 10 describe the particular parameters or characteristics that specific disposal options require or forbid in the material they accept. Chapter 6 describes “special wastes” or those generated in the removal of arsenic and radioactivity.

In general, the most important chemical characteristics of a residual material include: � pH � Toxicity potential, defined by the TCLP or the WET procedure in California � Contaminant concentration Coagulant sludge is an inert material that is mostly made up of the sediment that was in

the raw water and the solids added by the treatment chemicals. Unlike wastewater sludge (biosolids), water treatment plant sludge only has a biological component associated with algae and the biological material that may have been removed. Before dewatering, it is typically a

Jar testing equipment can be used to observe the effect polymers have on a

residual – gently mix samples of a residual with varying doses of polymer

and allow to settle


28

liquid material. Chemical characterization of these residuals has previously only been of interest to researchers in the field or to those utilities considering chemical recovery. However, disposal concerns and beneficial use opportunities have increased the awareness of constituents of the chemical sludges. As drinking water quality standards increase, so will the chemical levels in the waste streams.

The chemical characteristics of interest to a disposal site, such as a POTW for example, may be a simple measurement of pH on the concentration of a contaminant.

Analysis of wastes may need to be conducted based on the total concentration of chemical present or based on extraction procedures such as the TCLP or California’s WET test. The Toxicity Characteristics Leading Potential (TCLP) is described in detail in Chapter 4 and it is USEPA Method SW-1311 (USEPA 1998a). Its procedure can be viewed online at www.epa.gov/epaoswer/hazwaste/test/main.htm. It is a test to measure the toxicity of a material by subjecting the material to certain conditions and analyzing the amount of certain contaminants that have leached from the material. California requires its own procedure, termed the WET. This is similar to the TCLP, but it uses different test conditions. Appendix B includes a summary of the TCLP method and shows the TCLP contaminants and their limits. For liquid wastes, units of mg/L are appropriate and for solid wastes (dewatered sludges), units of mg/kg dry weight sludge would be appropriate. When trying to report results for comparative purposes it is useful to present all sludge data (dilute or concentrated) in terms of mg/kg dry weight. The chemical content of a residual will reflect the raw water quality as well as the removal efficiency of the treatment process. For example, processes designed to remove arsenic will have elevated levels of arsenic. But, it is important to consider that processes used to target one contaminant will often remove others. Each disposal option has criteria that must be met for chemical content of the material. Refer to the chapters on ultimate disposal options (Chapters 7 to 10) to determine what type of analyses to conduct on the water residuals. Three categories of characteristics are particularly important for residuals: Hazardous classification

� Levels of radioactivity � Whether they contain a mixture of hazardous and radioactive materials Each of these characteristics is based on legal definitions, and so are discussed in the

following chapter on regulations. Wastes that are classified by these characteristics are discussed in detail in Chapter 6, “Special Waste”.

For more information on Hazardous Waste Classification, go to

www.epa.gov/osw/hazwaste.htm


29

CHAPTER 4

REGULATIONS

This chapter will serve as an overview of the regulations governing drinking water residuals disposal. It is meant to help utilities assess the requirements that need to be considered for the residuals generated by their existing treatment, as well as allow an evaluation of the implications of alternative treatments. This is not a discussion of the regulations to which water systems must adhere in order for their drinking water be in compliance. It is instead a compilation of the regulations that could come into play for the various methods of handling and disposal of wastes generated by water treatment. Regulations governing the disposal of water treatment plant residuals can exist in federal, state, and local codes. Most water utilities are familiar with drinking water regulations that are enforced at the state level, but are based on one federal regulation: The Safe Drinking Water Act (SDWA). Unfortunately regulations governing water residuals disposal are not as straightforward, making it difficult for utilities to quickly determine the various requirements for treatment alternatives they are considering.

At the federal level, a number of regulations affect residuals disposal, depending on the type of residual produced and where the final disposal of the residual will be. These are summarized in this chapter. Figure 4.1 provides an overview of which regulations govern each type of treatment and disposal of residuals considered.

CLEAN WATER ACT

The Clean Water Act provides the federal authority to regulate the discharge of liquid material to any receiving water body in the U.S. (USEPA 1977). This law also requires that any indirect discharge, that is, a discharge to a sewerage system or publicly owned treatment works (POTW), be subject to pretreatment program requirements.

For an excellent summary of regulations that small water systems must be in compliance with on the federal level, see www.nesc.wvu.edu/pdf/train/products/regulations_chart.pdf


30

Source: SAIC 2000

Figure 4.1 Federal regulations governing the disposal of residuals

Discharge to Sewers (Pretreatment Program)

Name of Regulation: Clean Water Act, Section 403 What Does it Regulate? Liquid discharge of drinking water residuals to a sanitary sewer or

directly to a POTW The Clean Water Act regulates the discharge of liquid residuals by a drinking water utility to a sanitary sewer or directly to a POTW under Section 403. This type of discharge does not require an NPDES permit, but the discharge must comply with “pretreatment program requirements.” These requirements are generally implemented at the local level of government by a sewer authority or POTW with approval from USEPA. The pretreatment program requirements are usually site specific and are intended to ensure that the operation of the sewer facility (POTW) is not upset by the acceptance of the drinking water utility’s liquid residuals. The limits further ensure that the quantity or quality of the drinking water residuals do not adversely impact the final disposal method of the POTW’s biosolids, such as land application or direct discharge. Local limits vary significantly and can depend upon a great number or factors. These include, but are not limited to, the size of the POTW and the amount of contaminants in the liquid residuals. Because of these factors, it is difficult to state with certainty what requirements may be placed upon a facility discharging its residual to a POTW. Each case must be individually evaluated. The pretreatment regulations do not define the term “liquid.” However, these regulations prohibit the indirect discharge of “solids or viscous pollutants in amounts which will cause the

Form of Waste

Interim

Management

Direct

Discharge

(e.g., surface

water, wetland,

ocean)

Indirect

Discharge

(e.g., sanitary

sewer)

Underground

Injection

(e.g., deep well)

Land Disposal

(e.g., sanitary,

industrial, hazardous

landfill)

Reuse

(e.g., land

application)

Wetland/

Ocean

Disposal

Incineration

Regulatory

Programs

Safe Drinking

Water Act:

Underground

Injection Control

Program

40 CFR Parts 141-149

Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Clean Water

Act:

Dredge and

Fill Program


Clean Water

Act:

Pretreatment

Program

40 CFR Parts 403

Clean

Water Act:

NPDES

Program


Clean Air Act/

Resource

Conservation

Recovery Act

40 CFR Parts 50, 60-63, 26

Interim Treatment

(e.g., chemical precipitation,

holding pond, evaporation

pond/lagoon)

Liquid Residuals

(e.g., liquids, brines,

filtrates, etc.)

Solids/Sludge Residuals

(e.g., sludges, precipitates

spent materials/media)

Liquid Sludge

Disposal

Methods

Form of Waste

Interim

Management

Direct

Discharge

(e.g., surface

water, wetland,

ocean)

Indirect

Discharge

(e.g., sanitary

sewer)

Underground

Injection

(e.g., deep well)

Land Disposal

(e.g., sanitary,

industrial, hazardous

landfill)

Reuse

(e.g., land

application)

Wetland/

Ocean

Disposal

Incineration

Regulatory

Programs

Safe Drinking

Water Act:

Underground

Injection Control

Program


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Clean Water

Act:

Dredge and

Fill Program


Clean Water

Act:

Pretreatment

Program

40 CFR Parts 403

Clean

Water Act:

NPDES

Program


Clean Air Act/

Resource

Conservation

Recovery Act

40 CFR Parts 50, 60-63, 26

Safe Drinking

Water Act:

Underground

Injection Control

Program


Safe Drinking

Water Act:

Underground

Injection Control

Program


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Resource

Conservation

Recovery Act:

Subtitle C&D

Programs


Clean Water

Act:

Dredge and

Fill Program


Clean Water

Act:

Dredge and

Fill Program


Clean Water

Act:

Pretreatment

Program

40 CFR Parts 403

Clean Water

Act:

Pretreatment

Program

40 CFR Parts 403

Clean

Water Act:

NPDES

Program


Clean

Water Act:

NPDES

Program


Clean Air Act/

Resource

Conservation

Recovery Act

40 CFR Parts 50, 60-63, 26

Clean Air Act/

Resource

Conservation

Recovery Act

40 CFR Parts 50, 60-63, 26

Interim Treatment



pond/lagoon)

Interim Treatment



pond/lagoon)

Liquid Residuals

(e.g., liquids, brines,

filtrates, etc.)







Liquid Sludge

Disposal

Methods


31

obstruction to the flow in the POTW resulting interference” [CFR 403.5 (b)(3)]. Typically, a POTW would not accept the disposal of solid drinking water residuals through the sanitary sewer system.

Direct Discharge to Receiving Stream (NPDES Program)

Name of Regulation: Clean Water Act, Section 402 What Does it Regulate? Liquid discharge of any type of residual to a water body The Clean Water Act, under Section 402, forbids any discharge of a pollutant to any water body (including wetlands) without a permit. These National Pollutant Discharge Elimination System (NPDES) permits are site specific and set maximum allowable concentrations for a number of contaminants that could impact the aquatic life of the receiving water. Typically, NPDES permits can contain limits on total suspended solids (as low as 30 mg/L), pH, chlorine, arsenic, aluminum and other materials, as well as flow and temperature. The actual limits set by the permit are what are known as “water quality based effluent limits,” based on the anticipated chronic and acute toxicity of the contaminants on the aquatic organisms present in the receiving stream. Because the authority to enforce this law is typically delegated to the states, state agencies are responsible for developing these permits. There is quite a bit of variation from state to state regarding these permits, and the permits can also vary depending on the flow and quality of the receiving stream. Currently, most states allow the discharge of certain residuals streams, such as spent filter backwash water and settled water from processes. A few states have historically allowed softening residuals and clarifier blowdown streams to be discharged without treatment. In 2004, USEPA announced that it intends to consider national standards for the regulation of discharges from water treatment plants. In general, these limits are known as technology based effluent limits and would govern the drinking water industry as a whole. The final form of this regulation could take many forms, from not allowing any discharges, to setting national limits in certain contaminants. After review, USEPA suspended its work on this regulation but it could revisit this work in the future. USEPA indicated that if it had developed a technology based regulation for water plant residuals it would exclude drinking water systems serving fewer than 10,000 people.

FILTER BACKWASH AND RECYCLING RULE (FBRR)

Name of Regulation: Filter Backwash and Recycling Rule What Does it Regulate? Water systems that filter and produce a spent filter backwash

stream, a sludge thickener supernatant or a liquid from a dewatering process that is recycled back to some part of the process

The purpose of the FBRR is to require public water systems to review their recycle practices and, where appropriate work with the state primacy agency to make any necessary changes to recycle practices that may compromise microbial control of the water treatment plant’s process (USEPA 1991a). According to the USEPA, the FBRR applies to all public water systems that:


32

� Use surface water or ground water under the direct influence of surface water (GWUDI)

� Utilize direct or conventional filtration processes; and � Recycle spent filter backwash water (SFBW), sludge thickener supernatant, or

liquids from dewatering processes The FBRR requires that recycled SFBW, sludge thickener supernatant, and liquids from

dewatering processes be returned to a location such that all processes of a system’s conventional or direct filtration plant including coagulation, flocculation, sedimentation (conventional filtration only) and filtration, are employed. Systems may apply to the state for approval to recycle at an alternative location.

The FBRR also requires that systems notify the State in writing that they practice recycle. Systems must also provide the following information to the state:

� A plant schematic showing the origin of all recycle flows, the hydraulic conveyance used to transport them, and the location where they are recycled back into the plant and

� Typical recycle flow (gpm), highest observed plant flow experienced in the previous year (gpm), design flow for the treatment plant (gpm), and the state-approved operating capacity for the plant where the State has made such determinations

The FBRR does not limit the percentage of flow that can be recycled but some states have set such a limit, most commonly 10 percent.

SAFE DRINKING WATER ACT

Underground Injection

Name of Regulation: Safe Drinking Water Act – UIC What Does it Regulate? Liquid discharge of residuals to subsurface Liquid treatment residuals may be disposed by underground injection, although it is very expensive and only feasible in certain locations. Where the geology is complex, such as in mountainous areas it is unlikely that this technology could be implemented. Federal regulations addressing underground injection control (UIC) have been developed by the USEPA under the SDWA (USEPA 1979). Under this program, states may assume responsibility to implement the UIC program, provided they meet minimum federal standards. Federal UIC regulations prohibit the subsurface discharge of fluid through a well or hole whose depth is greater than its width without a permit. UIC permits generally include standard permit conditions, as well as substantive conditions addressing areas such as construction, operation, corrective action, monitoring and reporting, mechanical integrity, and financial responsibility. Permit-by-rule is authorized in certain instances (i.e., a permit is deemed to be issued if the permittee operates in compliance with specified regulatory conditions). The federal UIC regulations establish five classes of injection wells. UIC wells used for liquid residuals generated by drinking water residuals are likely to be Class I, II-R or V (other) wells. Underground injection is prohibited where it would cause any underground source of drinking water to exceed any SDWA mandated drinking water standards (i.e., MCLs) or otherwise affect public health. Because of the expense and complexity of this disposal option, it is not frequently utilized by water plants (SAIC 2000).


33

On-Site Dewatering

Name of Regulation: Safe Drinking Water Act What Does it Regulate? On-site storage or dewatering of residuals The SDWA requires that the state regulatory agency establish programs to protect areas surrounding a water well or well fields supplying public water systems from contamination. Any on-site dewatering must not pose a threat to drinking water wells.

RESOURCE CONSERVATION AND RECOVERY ACT OF 1976

Name of Regulation: Resource Conservation and Recovery Act What Does it Regulate? Disposal of hazardous, nonhazardous residuals to land, including

land application and landfilling RCRA concerns the handling of wastes both at currently operating facilities (such as

water plants) and at facilities yet to be constructed (USEPA 1991b). It was designed to meet disposal needs resulting from the Clean Water Act and The Clean Air Act. Those statutes require the removal of hazardous substances from air emissions and water discharges. Neither of these other statutes however, assured that the disposal of the waste materials generated would be environmentally sound. RCRA was intended to provide that assurance. RCRA specifies two ways in which a waste can be classified as hazardous: (1) by its presence on the USEPA lists, or (2) by evidence that the waste exhibits ignitable, corrosive, reactive or toxic characteristics. It also defines what a solid waste is. Water plant wastes are not on the list of specifically identified hazardous wastes, so that part of the definition does not apply. That leaves the properties of ignitability, reactivity, corrosivity or toxicity as a means of defining the residuals as hazardous. It is highly unlikely that water plant wastes will fail either of the first two (ignitability or reactivity). A waste is classified as corrosive if it has a pH of <2 or >12.5. It is possible that membrane cleaning solutions, filtrate from lime conditioning of sludge in a filter press, and brines from acid regeneration of ion exchange resins would fall outside these limits. The pH can be adjusted with appropriate neutralization. Extraction tests were designated by USEPA in the Federal Register as the method to be used in identifying in a solid waste the characteristic of toxicity. The presence in the extract from a representative waste sample of any number of contaminants at or above a specified regulatory level constitutes failure of the test, and furthermore makes the waste subject to regulation as a hazardous waste per Subtitle C of RCRA. The toxicity characteristic leaching procedure (TCLP), USEPA Method SW-1311 is used as the indicator of toxicity in a waste (USEPA 1998a). The TCLP is designed to determine the mobility of 40 organic and inorganic analytes present in liquid, solid, and multiphasic wastes. If the material fails this test, it is considered hazardous. The analytes and their limits are included in Appendix B. The TCLP test procedure is described in Method SW-1311, which can be viewed online at: www.epa.gov/epaoswer/ hazwaste/test/main.htm. The presence of radioactivity does not classify a waste as hazardous. This process is shown schematically in Figure 4.2. The sections of 40 CFR Part 261 that are used in this process can be viewed online at: http//:www.epa.gov/osw/hazwaste.htm.


34

Source: Adapted from USEPA 2005b *Defined in 40 CFR Part 261.2 HDefined in 40 CFR Part 261.4 IDefined in 40 CFR Part 261.20 'Defined in 40 CFR Part 261.30

Figure 4.2 Hazardous waste determination decision tree

Solids Disposal in a Municipal Solid Waste Landfill

A material can be disposed of in a municipal solid waste landfill if it is a solid and if it is

not hazardous. It is considered a solid if it passes the Paint Filter Test (see Chapter 3) and it is characterized as non-hazardous if it meets the four RCRA requirements including toxicity (per the TCLP) corrosivity (per pH), ignitability and reactivity.

If the material passes the TCLP (see Chapter 3), and is considered a solid, then Subtitle D of RCRA governs its management. This section of RCRA is meant to ensure that the landfill will not endanger the surrounding environment. This section of RCRA specifically prohibits the disposal of a liquid waste in a landfill (USEPA 1991b).

Solids Disposal in a Hazardous Waste Landfill

Subtitle C of RCRA concerns the disposal of hazardous wastes. Under RCRA the basic

criteria for determining whether a waste should be classified as hazardous are ignitability,

2. Is waste excluded from the

definition of solids or hazardous

waste?H

1. Is material a solid waste?*

3. Is waste a listed or characteristic

hazardous waste?I

4. Is waste delisted?'

Material is not subject to

RCRA Subtitle C Regulation

Waste is subject to RCRA

Subtitle C Regulation

No

Yes

No

Yes

No

Yes

Yes

Yes



waste?H



waste?H

1. Is material a solid waste?*1. Is material a solid waste?*

3. Is waste a listed or characteristic

hazardous waste?I3. Is waste a listed or characteristic

hazardous waste?I

4. Is waste delisted?'4. Is waste delisted?'









No

Yes

No

Yes

No

Yes

Yes

Yes


35

corrosivity, reactivity, and toxicity (USEPA 1991b). Sludge determined to be hazardous or that contains polychlorinated biphenyls (PCBs) in concentrations greater than 50 ppm is regulated under Subtitle C of RCRA and the Toxic Substances Control Act. It can also be designated as hazardous if it fails the TCLP, as described above. It would be highly unlikely that a coagulant sludge would fail the TCLP, but an adsorbent media, exposed to elevated levels of a contaminant for a long period of time, could fail this test. For example, adsorbent media for arsenic removal, or ion exchange resins could fail the TCLP, and so would be disposed of as a hazardous waste.

The uniform hazardous waste manifest system developed by the USEPA makes possible the tracking of hazardous waste from its generation to the point of ultimate disposal. If manifests are correctly processed, the generator of the hazardous waste, who is ultimately responsible for the waste disposal, can reliably track the waste from "cradle" to "grave.” To ensure that a hazardous waste can be monitored from its generation to its disposal, each RCRA hazardous waste generator must obtain an identification number from the USEPA.

If a residual is a hazardous waste, it must be managed in compliance with the following requirements:

� Hazardous waste generators must obtain a USEPA identification number, as well as comply with packaging, marking, manifesting, accumulation and storage limits, record keeping and reporting, and land disposal restriction (LDR) requirements. Note that the technical standards applicable to the management of hazardous waste vary depending on how much waste is generated per month. A water plant that generates residuals that must be managed as hazardous waste may be subject to the hazardous waste generator requirements.

� Hazardous waste transporters must obtain a USEPA identification number, as well as comply with manifest and spill cleanup/reporting requirements.

� Hazardous Waste Treatment, Storage, Disposal Facilities (TSDFs) must obtain a USEPA identification number, as well as comply with general facility standards, preparedness and prevention, permitting, contingency plans and emergency procedures, manifest, record keeping and reporting, release, closure and post-closure, financial, corrective action, land disposal restriction, and management unit specific (e.g., surface impoundments, waste piles, and landfills) requirements. A water plant could be subject to TSDF requirements if it decides to accumulate hazardous waste for greater than 90 days or to treat or dispose of its hazardous waste on-site.

To manage the universe of hazardous waste generators, USEPA has classified them on the basis of the quantity of waste produced. These classes are as follows: (1) Large Quantity Generators (LQG) are facilities that produce over 1,000 kilograms per month of hazardous waste (weight is determined based on the condition of the waste disposed); (2) Small Quantity Generators (SQG) are facilities that produce greater than 100 kilograms per month of hazardous waste but less than 1,000 kilograms per month, and accumulate less than 6,000 kilograms at any one time; and (3) Conditionally Exempt Small Quantity Generators (CESQG) are facilities that generate less than 100 kilograms per month of hazardous waste. There are also restrictions on the amount of waste a CESQG may accumulate. LQGs are subject to full regulation. SQGs are subject to reduced regulation. CESQGs are generally exempt from Subtitle C regulation, provided they appropriately manage their waste in permitted or licensed state municipal or industrial landfills. Small water systems would generally be considered either a SQG or CESQG.


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Any hazardous waste that will be disposed or placed on the land must comply with the land disposal restriction (LDR) regulations. Land disposal included disposal or placement in landfills, land treatment, surface impoundments, waste piles, or injection wells (40 CFR Part 268.2c). These regulations establish treatment standards for each hazardous waste. The waste must meet the standard prior to land disposal. Compliance with the LDR requirements may force water treatment facilities to treat their waste prior to land disposal.

Finally, any water utility that generates a hazardous waste must be careful regarding whether that waste is mixed with other solid wastes. Under 40 CFR 261.3, a mixture of a characteristic hazardous waste and a solid waste is a hazardous waste unless the resultant mixture does not exhibit any characteristic of hazardous waste. Facilities may not mix characteristic hazardous waste with other wastes to dilute the characteristic unless it is a necessary step in the treatment process (SAIC 2000).

Land Application of Liquid Residuals

Parts 257 and 258 of RCRA are generally used by states to develop permits and guidelines for the land application of liquid residuals. For example, liquid residuals from drinking water treatment plants have been sprayed on land for crop enhancement, dust control or restoration. To use these non hazardous residuals in land application, the residuals are subject to Parts 257/258 provisions which are predominantly implemented and enforced by the states, include requirements addressing location in floodplain, protection of endangered species, protection of surface water (e.g., waste management practices shall not cause a point source discharge in violation of CWA 402, or a nonpoint source discharge in violation of applicable legal requirements) and ground water (e.g., waste management practices shall not contaminate an underground drinking water source), land application to food chain crops (e.g. cadmium and PCB restrictions), minimizing disease vectors, protection of air quality and limits on explosive gases.

THE ATOMIC ENERGY ACT OF 1954, AS AMENDED

Name of Regulation: Atomic Energy Act and State Regulations What Does it Regulate? Handling and disposal of residuals containing radioactive material

Disposal of Residuals Containing Radioactivity

This act requires the Nuclear Regulatory Commission (NRC) to regulate the civilian, commercial, industrial, academic, and medical use of man-made nuclear materials. The radioactive materials in water treatment residuals are naturally occurring and so, in general, are not subject to the Act. However, uranium is specifically listed in this Act, so uranium containing water treatment residuals are covered. The Act enables the NRC to relinquish some of its regulatory authority over source materials to states through the signing of an agreement between the state’s governor and the NRC chairperson. Currently, 33 states have entered such agreements and are referred to as “Agreement State”. Agreement States must establish radiation protection programs compatible with NRC’s programs and the NRC remains involved with state licensing, inspection, and rule changes, among other things.


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The Low-Level Radioactive Waste Policy Act (42 USC 2021b(9)) defines low-level radioactive waste (LLRW) as “radioactive material that (a) is not high level radioactive waste, spent nuclear fuel, or byproduct material (as defined in section 2014(e)(2)…); and (b) the Nuclear Regulatory Commission classifies as low-level radioactive waste.” Generally, LLRW can be thought of as byproduct material as defined in 42 USC 2014(e)(1)(i.e., yielded in or made radioactive by the production or use of special nuclear material) that does not fall into any other category. In addition, LLRW can contain source or special nuclear material. Water treatment residuals would not meet the definition of byproduct material as defined under 42 USC 2014(e)(2)(waste from processing uranium or thorium ore), (Idaho DEQ 2007), and so are not subject to this regulation. The radioactive materials in water plant residuals except for uranium are naturally occurring, and so are not subject to the Atomic Energy Act. States have produced regulations and guidance that address naturally occurring radioactive materials. For example, in Idaho, IDAPA 58.01.10, Rules Regulating the Disposal of Radioactive Materials Not Regulated under the Atomic Energy Act of 1954, as Amended, regulates the disposal of radioactive materials not regulated under the Atomic Energy Act of 1954, naturally occurring radioactive materials (NORM) or technologically enhanced naturally occurring radioactive materials (TENORM) waste (Idaho DEQ 2007).

TENORM is defined as any naturally occurring radioactive materials not subject to regulation under the Atomic Energy Act whose radionuclide concentrations or potential for human exposure have been increased above levels encountered in the natural state by human activities. TENORM does not include source, byproduct or special nuclear material licensed by the U.S. Nuclear Regulatory Commission under the Atomic Energy Act of 1954. Mixed waste “contains both hazardous waste and source…or byproduct material” subject to the Atomic Energy Act of 1954 (42 USC 6903(41)), so is regulated under both RCRA and the Atomic Energy Act.

DEPARTMENT OF TRANSPORTATION (DOT) REGULATIONS (49 CFR 171 TO 180)

Name of Regulation: DOT regulations What Does it Regulate? Transport of hazardous or radioactive material These regulations govern shipping, labeling, and transport of hazardous and radioactive materials (USDOT 1976). These requirements must be met by any residual that is characterized as “hazardous” or as containing radioactivity, at a level greater than 2,000 pci/g.

For more information on radioactivity and a list of

Agreement states, see http://www.nrc-stp.ornl.gov/


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COMPREHENSIVE ENVIRONMENTAL RESPONSE, COMPENSATION, AND

LIABILITY ACT (CERCLA)

Name of Regulation: CERCLA What Does it Regulate? Release of contaminant in a residual through a spill or otherwise

that endangers human health or damages the environment The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, 42 USC 9605 et seq.) is commonly known as “Superfund.” This regulation applies to the release or threat of release of hazardous substances (including radionuclides) that may endanger human health and the environment. If disposal of hazardous or radionuclide-contaminated residuals results in a release or threat of release that endangers human health or the environment, CERCLA may require cleanup of the hazardous substance.


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CHAPTER 5

THICKENING AND DEWATERING

For many utilities, it makes sense to treat their residuals on-site in order to thicken or

dewater them. This results in less volume that has to be transported and disposed. The treatment of solid/liquid wastes produced in water treatment processes involves the separation of water from the solid constituents to the degree necessary for the selected disposal or beneficial use method. Therefore, the required degree of treatment is a direct function of the ultimate disposal or beneficial use method. Water treatment sludges from a chemical coagulation process typically have a 0.5 to 2.0 percent solids concentration. These solids are difficult to gravity thicken to greater than a three- to four-percent solids concentration. Sludge resulting from lime softening can be removed from settling basins at solids concentrations as high as 10 percent and may gravity thicken to a 30 percent solids concentration. There are several residual treatment methodologies which have been practiced in the water industry. Figure 5.1 shows the most common residuals handling options available, listed by general categories of thickening, dewatering, and disposal or utilization. In choosing a combination of possible treatment process trains, it is probably best to first identify the available disposal options and their requirements for a final cake solids concentration. Most landfill applications will require a ‘handleable’ residual which may limit the type of dewatering devices that are acceptable. Methods and costs of transportation may affect the decision of “how dry is dry enough.” The criteria should not be to simply reach a given solids concentration but rather to reach a solids concentration of desired properties for the handling, transport, and disposal options available. Table 5.1 shows a generalized range of results of final solids concentrations from different dewatering devices for liquid residuals.

Table 5.1

Range of cake solid concentrations obtainable

Percent solids concentration

Lime residual* Coagulant residual

Gravity thickening 15 - 30 3 - 4

Sand drying beds 50 20 - 25H

Storage lagoons 50 - 60 7 - 15H

Freeze thaw 80 20 - 40

Scroll centrifuge 55 - 65 18 - 25

Belt filter press 55 - 65 15 - 22

Vacuum filter 45 - 65 Not used

Pressure filter 55 - 70 25 - 45

Source: Adapted from Cornwell 2006 *Surface water sources can have concentrations more like coagulant residuals HCan be much higher if extended air drying is used


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Disposal

Permanent

Lagoon

Dewatering/TreatmentConditioning

Lime

ThickeningWaste Source

Wastewater

Plant

Land

Application

Landfill/

Monofill

Direct

Discharge

Useable or

Saleable

Product

Belt Filter

Press

Vacuum

Filter

Pressure

Filter

Centrifuge

Sand Bed/

Freeze Thaw

Dewatering

Lagoon

Recalcination

Alum

Recovery

Conditioning

Coagulant

Clarifer

Gravity

Thickening

Thickening

Storage/

Equalization

Softening

Unit

Spent Filter

Backwash

Alum

MembranepH adjust, neutralize chlorine

Adsorption / IX

Gravity thickening with chemical treatment

Source: Adapted from Cornwell 2006

Figure 5.1 Sludge handling options

PUMPS AND PIPING

The unthickened sludge coming from the sedimentation basin in a coagulation process is generally fairly dilute, ranging from 0.5 percent to 2 percent solids concentration for alum sludges. These sludges can be conveyed by gravity or siphoning from the sedimentation basin to a sludge pumping station. Spent filter backwash water is very dilute, and so is easily pumped. Pumping of unthickened sludge can usually be accomplished using centrifugal pumps. Sludges from lime clarifiers are much thicker and may need to be handled by positive displacement pumps. Residuals thickened in gravity thickeners can be expected to achieve a solids concentration of three to four percent for coagulant sludges, and up to 30 percent for lime softening sludge. These thickened residuals generally can be pumped by progressive cavity pumps or other types of positive displacement pumps. Coagulant residuals in the three to four percent range can sometimes be pumped by centrifugal pumps; engineering judgment is needed as to which system is appropriate.


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EQUALIZATION

Spent filter backwash is produced over a relatively short time periods (around 15 minutes

per filter) but at a high instantaneous flow rate. Equalization (EQ) is a method whereby the SFBW is captured in a storage device and released over a longer period of time and, therefore, at a lower flow rate. For example, capturing the volume of one backwash and releasing it over the next hour will reduce the flow to about 25 percent of the instantaneous rate. Reduction of the flow rate through equalization can be useful in sizing downstream treatment devices, reducing impacts to the main treatment plant if recycle is used, reducing impacts at wastewater plants or sewer line size requirements, or for reducing flow rates into the receiving stream. The allowed rate of release from the equalization basin is established by the downstream control, e.g. the sewer line capacity, regulatory or treatment limitations on recycle, stream flow discharge limits. The size of the equalization storage device is set by the SFBW produced per backwash, backwash frequency and the allowed or design flow release. The EQ basin storage volume is determined based on a flow balance of SFBW entering the basin and the rate of release of equalized SFBW leaving the basin. The storage curve is typically shown over a 24-hr period of fill-and-draw from the EQ basin. Because the rate of SFBW flow into the EQ basin usually exceeds the rate of discharge from the basin, the volume in the basin increases over time as long as filter backwashing is occurring. The volume in the EQ basin will then decrease until the next cycle of washes begins. The peak of the storage curve is the total EQ basin volume required to meet the backwash assumptions used.

In sizing an EQ tank, it is important to make sure that operation of the treatment plant itself is not impacted. Backwashing of a filter should not have to wait because the EQ tank is full, unless, of course, the plant has a lot of excess filter capacity. In order to size an EQ tank, the operators must determine the frequency at which they need to be able to wash filters, how many in a row, how many per shift, etc. It is also important to associate a production flow with the number of filter washes. Some facilities may wash all filters each day independent of the raw flow, while others may operate fewer filters at lower production levels and hence wash fewer filters. Additional decisions need to be made such as the volume of SFBW produced per day, the design (perhaps worst-case) number of filter washes per day, and the frequency of backwashes. As indicated, one of the more critical decisions is determining frequency of backwashing filters. The criteria resulting in maximum flexibility would allow for backwashing one filter immediately after another until all filters are backwashed, referred to as sequential backwashing (some plants can also backwash more than one filter at a time). This of course, results in a large EQ basin. On the other end of the spectrum is a criteria of evenly spacing backwashes. This criteria would minimize the EQ volume required, but also place the largest constraint on operations.

For small systems with only a few filters, when SFBW is recycled equalization is critical to maintain good plant performance. Since backwash rates are several times filtration rates, major filter upsets can occur when equalization is not used.


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GRAVITY THICKENING

Thickening Tanks

Residuals thickening is performed primarily for reduction in the volume of residuals

which will require subsequent treatment and disposal. After removal from a clarifier or sedimentation basin most water sludges can be further thickened in a gravity concentration tank. Thickening can be economically attractive in that it reduces the sludge volume and results in a more concentrated sludge for further treatment in the dewatering process. Some dewatering systems will perform more efficiently with higher solids concentrations. Thickening tanks can also serve as equalization facilities to provide a uniform feed to the dewatering step. Although there are a few types of thickeners available on the market, the water industry almost exclusively uses gravitational thickening. Gravity residuals thickeners are generally circular settling basins with either a scraper mechanism in the bottom or equipped with sludge hoppers. They may be operated as continuous flow or as batch ‘fill and draw’ thickeners. For continuous flow thickeners, the residuals normally enter the thickener near the center of the basin and are distributed radially. The settled water exits the thickener over a peripheral weir or trough and the thickened residuals are drawn off the basin. For tanks equipped with a scraper mechanism, the scraper is located at the thickener bottom and rotates slowly. This movement directs the residuals to the draw-off pipe near the bottom, center of the basin. The slow rotation of the scraper mechanism also prevents bridging of the solids. The basin’s bottom is sloped to the center to facilitate collection of the thickened residuals. Batch fill and draw thickening tanks are often equipped with bottom hoppers. In these tanks sludge flows into the tank, usually from a batch removal of sludge from the sedimentation basin, until the thickening tank is full. The sludge is allowed to settle and a telescoping decant pipe is used to remove supernatant. The decant pipe may be continually lowered as the solids settle until the desired solids concentration is reached or the sludge will not thicken further. The thickened residuals are then pumped out of the bottom hoppers to further treatment or disposal. Design of batch or continuous flow thickeners is usually accomplished based on previous experience of similar full scale installations, laboratory settling tests, or pilot thickening studies. Two different performance factors can affect the sizing of thickeners. If the supernatant from the thickener is discharged to a receiving stream then generally there will be a suspended solids limitation placed on the discharge. If the supernatant is recycled, some utilities will desire to reach a certain quality in the stream prior to recycle. For both of these cases the overflow rate of the thickener must be sized to meet the effluent quality requirements. Sizing of the thickener in this case is based on the hydraulic loading, flow per thickener area and is expressed as gpm/ft2 or m3/min•m2. The hydraulic loading is equivalent to the solids settling velocity, ft/min or cm/min.

The second performance factor of the thickener is the desired underflow solids concentration. In some cases achieving a certain thickened solids concentration will set the thickener size. Sizing of the thickener in this case is based on the solids flux, sometimes referred to as the solids loading rate and is expressed as mass per time per thickener area, lb/ft2•hr or kg/m2•hr. For coagulant residuals, a loading rate of 0.1 to 0.4 lb/hr/ft2 is a common range. Lime thickeners can be in the range of 1 lb/hr/ft2. The loading rate to the thickeners would be sized based on the pump rate from the sedimentation.


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For example, if the pump for the sedimentation basin residuals to the thickener is 50 gpm and the sludge is 0.5 percent solids concentration, then the pounds per minute pumped is 50(8.34)(.005) = 2.1 lb/min or 2.1(60) = 125 lb/hour equivalent. If the allowed loading rate is 0.1 lb/hr/ft2 then 125/(0.1) = 1250 ft2 thickener is required.

Plate Settlers

Plate settlers have found some application for settling solids from SFBW and from

clarifiers that discharge a residual with low solids content such as contact clarifiers and some upflow blanket clarifiers. Some thickening of the solids can take place in the bottom storage area of the plate settlers if it is appropriately sized.

Conditioning

Laboratory evaluations to meet a given suspended solids or turbidity quality are often done using standard jar test techniques. In this case the required overflow rate with and without polymers can be estimated. Water residuals conditioning refers to the variety of chemical and physical techniques for altering residual characteristics to make subsequent removal of water more efficient. There is no clear-cut, accepted conditioning method practiced for a given type of sludge. A conditioning agent that works well at one plant may not work at a similar plant. Conditioning of water plant residuals is generally only applicable to coagulant residuals and spent filter backwash water. Residuals from lime softening clarifiers are more easily dewatered and conditioning agents are seldom used. With coagulant residuals, conditioning agents are needed to either assist in the water removal processes or may be used to affect compressibility and minimize media clogging, such as in filter press operation. When conditioning is used for water/solids separation, polymers are generally the agent of choice. When the objective of conditioning is to prevent media clogging, lime has been traditionally utilized although recently polymers have successfully been used for this purpose. Polymer addition has been useful, and in fact almost required for dewatering coagulant residuals by either non-mechanical methods such as sand drying beds or mechanical methods such as centrifuges, belt filter presses, and pressure filters. When first selecting a polymer type, a series of screening tests is required. It is possible to visually screen several polymers by simply adding increasing doses to small beakers of sludge and viewing the floc. While ideal doses do not look the same for different polymers and sludges, this procedure does allow rapid screening of different polymer types.

NON-MECHANICAL DEWATERING

Many small systems use non-mechanical methods to dewater their residuals. These methods are typically called “drying beds” and they vary by whether the bottom is sealed, how the solids are removed, and how deep and how often they are filled. This section describes the proper installation of these methods and directs the user to more detailed sources for the proper design information. Figure 5.2 shows a successful dewatering operation.

Proper design of these beds is important in order to protect underlying groundwater sources or nearby surface waters.


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Nonmechanical processes described in this chapter can successfully dewater residuals. Figure 5.3 shows the results of a side-by-side test of two nonmechanical dewatering processes – sand drying bed and freeze thaw bed, on the same residual. The solids dewatered using the freeze-thaw method had significantly lower moisture content than did the solids from the drying beds.

Figure 5.2 Nonmechancial dewatering

Figure 5.3 Solids dewatered by two different nonmechanical processes – drying beds (on

top) and freeze-thaw (on bottom)

Drying beds


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Sand Drying Beds Description

Developed initially for dewatering municipal wastewater sludges, sand drying beds have

been widely used for dewatering water treatment plant sludges. Sand drying beds operate on the simple principle of spreading the residual out and letting it dry. As much water as possible is removed by drainage or decant and the rest of the water evaporates until the desired final solids concentration is reached. Sand drying beds range in complexity from dumping the residuals in a clear area, and hoping something happens, to a well designed bed with sophisticated automated drying systems.

Drainage (percolation), decanting, and evaporation are the primary mechanisms for dewatering residuals in sand drying beds. Following residuals application, free water is allowed to drain from the residuals into a sand bottom from which it is transported via an underdrain system consisting of a series of lateral collection pipes. This process continues until the sand is clogged with fine particles or until all the free water has been drained, which may require several days. Secondary free water removal by decanting can take place once a supernatant layer has formed. Decanting can also be utilized to remove rain water that would otherwise hinder the overall drying process. Water remaining after initial drainage and decanting is removed by evaporation over a period of time necessary to achieve the desired final solids concentration. The amount of water that needs to be evaporated is the controlling factor in bed sizing.

Design considerations for drying beds include: � Percentage of water that can be drained or decanted from the sludge � Loading rate (lb/ft2) � Time it takes for evaporation � Time required for cleaning

Maximizing the water removed by drainage and decant will reduce the overall required

bed size.

Design Several models have been developed to estimate a required sand drying bed area for a particular water utility. In a book published by ASCE and AWWA (1996) the drying bed size is based on the effective number of uses that may be applied to each bed and the depth of residuals applied onto the bed. In Cornwell (2006) the sizing is based on a monthly mass balance that takes into account monthly variations in solids production and evaporation. When sizing sand drying beds, solar beds, evaporative ponds, or dewatering lagoons it is important to remember that all methods ultimately rely on net evaporation (evaporation minus rainfall). Since evaporation varies tremendously in most climates from month to month, annual averages are not reliable for design. The other complicating factor is that, as discussed in Chapter 3, sludge production can vary widely from month to month. Design of these

To find evaporation data, first check with the National Climate Data Center of the National Oceanic and Atmospheric Administration (NOAA), online at

www.ncdc.noaa.gov. More information may also be obtained from local weather monitoring stations.


46

evaporative-dependant devices must be based on the paired variation of evaporation and solids production.

Solar Drying Bed or Evaporation Ponds Solar drying beds are similar to sand drying beds in terms of shape and operation. However, they are constructed with sealed bottoms. These beds have little or no provisions for water to be removed through drainage; all residuals drying is accomplished through decant of free water followed by evaporation. For coagulant type residuals, decanting of the free liquid can be used to reduce evaporation time. For pure liquids such as brines, however, evaporation is the only mechanism for drying. A principal advantage of this type of drying bed is low maintenance costs and ease of cleaning. No sand replacement costs are associated with this type of drying bed, and since the bottom of these beds are sealed, neither initial underdrain costs nor underdrain repair costs are incurred. Also, because the entire solar bed bottom is often paved or concrete, cleaning with front end loaders can be done quickly and efficiently. Because solar beds rely primarily on evaporation, they typically have lower solids loading rates than sand drying beds. Most solar beds are located where evaporation rates are high. As discussed with sand beds, an evaporative pond relies solely on net evaporation. In the case of brine or other liquid residuals, the whole pond depth must be evaporated over time. Ponds can be operated to work a ‘steady state’. That is the pond does not ever have to empty, as long as the monthly depth loading into the pond equals or is less than the monthly evaporation. For example, a 20 ft x 20 ft pond operating with 5 inches/month of net evaporation could receive 1,250 gallons/month of new brine:

(L) (W) (evaporation/12) (7.48) = (20) (20) (5/12) (7.48) = 1250 gallons/month

Dewatering Lagoons Dewatering lagoons are very similar to sand drying beds except that they operate at much higher loadings. The dewatering lagoon should be equipped with a decant structure and underdrains. For a dewatering lagoon, the lagoon is filled over a long time period and then allowed to dry for a long period while another lagoon is filled. Dewatering lagoons can have an advantage over sand drying beds in reducing peaks, since the loading is often spread over several months. Whereas, a sand bed is filled and cleaned on a regular schedule, (e.g., monthly), a dewatering lagoon may be filled for several months followed by several months of drying. Very often the overall land area for a dewatering lagoon and a sand bed system are roughly the same, only the fill/dry/clean cycles are different. Because dewatering lagoons use a much higher

In a very simple example, if 2 ft of 2 percent solids sludge is applied to a sand bed and it is desired to achieve 20 percent solids, then 0.2 ft of sludge would remain after drying ((2/20)2) or 1.8 ft of water must evaporate. If as an example, the net evaporation is 4 in/mo then it would take 5.4 months to evaporate. Therefore, under this example, the bed or pond would be unavailable for a new residuals loading for about six months.


47

loading rate, the drainage volume would generally be lower than a sand drying bed. The main difficulty in sizing a dewatering lagoon is in predicting the drained solids concentration after the loading is complete. Plugging of the sand media on the bottom of the dewatering lagoon with multiple loadings is difficult to predict and would require a carefully planned pilot test. Solids at the bottom of the lagoon would have a higher solids concentration than solids at the top of the lagoon and a net average solids concentration must be estimated. During the evaporation phase the bottom layers often do not dry out. Some utilities have found that tilling the sludge during the evaporative cycle helps to expose all of the residuals to drying. A storage lagoon, as its name implies is simply a large pond into which the residuals are pumped. Usually there is an overflow weir to allow clean water to be discharged to a stream. The remaining solids settle to the bottom when, depending on the lagoon size, they may be held for years between cleaning. The solids never really dry unless the pond is eventually drained and the solids undergo evaporation. At that time the solids can be removed by earth moving equipment. Contractors can also be hired to dredge the wet solids from the lagoon bottom and haul them away for dewatering and disposal. When sizing or operating a lagoon, it is generally a good idea to have at least the top half of the lagoon as ‘clear’ water so that the overflow from the lagoon into the stream can meet discharge standards and solids from the settled sludge are not carried over in the release. In order to determine the storage volume for the solids, a thickened solids concentration must be assumed, and this is really an unknown value. The sludge at the bottom of the lagoon will be much thicker than the sludge at the desired half-full level.

Freeze-Thaw Beds When residuals are subjected to freezing, the resulting volume reduction and increased solids concentration is appreciable. Typically, the volume reduction is well over 70 percent, and solids concentrations may reach as high as 80 percent when freeze-thaw is followed by evaporation. Freeze-thaw followed by evaporation dramatically converts the residuals from a fine particle suspension to granular particles. The granular particles often resemble coffee grounds in both size and appearance, and they do not break apart even after vigorous agitation. If the frozen mixture is placed on a porous medium, the water drains away easily upon thawing. As one might expect, freeze-thaw beds are operated most effectively in northern climates, with a range of effective operation beginning at approximately 40o north latitude and extending northward. (The 40o north latitude runs horizontally across the United States, roughly through Philadelphia, Indianapolis, and Salt Lake City). Some water treatment plants in cold climates already take advantage of this process by modifying the operation of their lagoons or drying beds. One technique is to decant a lagoon down to the residuals interface and allow it to freeze over the winter months. This technique is not always successful because the residuals do not freeze to the bottom. Another technique is to pump a shallow layer (20 to 45 cm) of residuals from a storage lagoon into drying beds or ponds that are then allowed to freeze in the winter. This technique works well because the residuals usually freeze completely, but it requires a considerable amount of land and storage volume. Combination sand drying beds and freeze-thaw beds can also be utilized. In this case the design must consider the evaporative condition for the drying bed cycle and the freezing and thawing conditions for the freeze-thaw cycle.


48

The design elements and operational considerations for freezing beds are extensively covered by Martel (1989), Cornwell and Koppers (1990) and Cornwell (2006). The basis of design for a freezing bed allows shallow layers of residuals to be applied to a bed. Each layer should be allowed to freeze prior to application of a subsequent layer on top. Martel (1989) demonstrated that this procedure maximizes the total cumulative freezing depth of the residuals and, thereby, minimizes the required freezing bed area and cost. Some operator attention would be necessary every day to ensure the layer has completely frozen and to apply the next residuals layer. Another consideration in the design of layered freezing beds is the basis of design with respect to the residuals quantity. The two approaches that could be considered are as follows:

� Design the layered freezing beds only for the residuals generated during the winter season.

� Design the layered freezing beds to process the residuals generated during the entire year. This would require storage of the residuals generated during the spring, summer, and fall.

If the residuals have to be stored from the spring through the fall prior to being applied to the freezing beds, the design should carefully size the residuals storage facilities and evaluate how to pump these residuals to the beds. The beds could be designed to operate as layered freezing beds during the winter months and as sand drying beds during the spring, summer, and fall. A sizing analysis of both the freeze-thaw and sand drying bed would have to be done to determine which scenario is limiting and requires the most area. This type of design would eliminate the need for extensive residuals storage that is necessary for processing all the residuals through a layered freeze-thaw method. Another viable approach for sizing freezing beds would be to calculate the freezing and thawing depth of only a single bulk loading. This type of design would be similar to a sand drying bed or a dewatering lagoon, but in the winter months the residuals on the bed are subjected to a freeze-thaw treatment cycle. While freezing a onetime bulk loading is not as efficient as multiple shallow layers, it would provide for a less operator intensive operation, and the combined sand drying bed and freeze-thaw bed would eliminate storage facilities. Regardless of which freeze-thaw design approach is selected, each design should incorporate a sand bottom, underdrains, an inlet with energy dissipation devices, and an effective decant system. Examples previously shown for sand drying beds could be considered for freeze-thaw beds as well. Polymer addition should be considered to maximize the removal of water from the residuals prior to freezing. This would reduce the residuals depth to be frozen and would allow a higher solids loading rate and depth. After the freeze-thaw cycle, the freezate should be decanted as soon as possible. The remaining residuals must be allowed to air dry in order to achieve their typical coffee ground texture. With freeze-thaw treatment, the air drying process is usually much faster than for residuals that have not experienced freeze-thaw treatment. Cleaning of the freeze-thaw beds could be done with front-end loaders provided runways and ramps are installed similar to those in sand drying beds.

MECHANICAL DEWATERING

A variety of mechanical devices are used in water treatment plants to dewater residuals.

Because of the cost and complexity of these systems, however, they are generally not used in


49

small systems. This section describes the equipment. Much more information on the use and design considerations for this type of equipment can be found in Cornwell (2006).

There are four basic mechanical dewatering devices used in water treatment. Vacuum filters (used only for lime residuals), centrifuges, belt presses and filter presses that are used for both lime and coagulant residuals.

Centrifuges

Centrifugation of residuals is basically a shallow depth settling process enhanced by applying centrifugal force. The basic physical principle of centrifugal force is that a moving body tends to continue in the same direction; if that body is forced to change directions, it resists the change and exerts a force against whatever is resisting it. In the case of centrifugal force, the force applied by the body is radially outward from the axis of rotation.

The major type of centrifuge used for the dewatering of water plant sludge is the scroll-discharge, solid bowl decanter. The solid bowl centrifuge (also called scroll or decanter centrifuge) is a horizontal unit that utilizes a scroll conveyor inside the centrifuge bowl (see Figure 5.4). Figure 5.5 shows a schematic of a small skid mounted unit. The unit is fed continuously with the solids settling against the bowl wall. The scroll rotates at a slightly different speed than the bowl and conveys the dewatered residuals to the small end of the centrifuge where it is discharged. The water is directed from the central axis of the centrifuge toward the centrifuge’s large end where it is discharged. The water exits through adjustable weirs (level rings), which also control the pool depth.

Cover

Differential

speed

Main drive

sheave

Feed pipes

(sludge and

chemical)

Bearing

Base not shown

sludge cakedischarge

Centratedischarge

gear box

Rotating

conveyor

Rotating bowl


Figure 5.4 Example centrifuge system


50

Photo courtesy of AlfaLaval, Inc.

Figure 5.5 Schematic of skid mounted centrifuge system

An advantage of the centrifuge when compared to other dewatering methods is the relatively small space requirement. Additional space is required near the centrifuge for the following:

� Polymer storage, mixing tank and pumps � Sludge feed pumps and piping � Overhead hoist � Proper operational and maintenance space Centrifuges are often located on upper floors of the sludge building so that the cake may

be discharged into trucks or hoppers below. Another operational consideration is the solids concentration of the residuals feed. It has

been demonstrated that for a particular set of centrifuge operational constraints, a well controlled feed concentration will produce consistently better results than a varying concentration. For centrifuges, it is usually advantageous to vary the hydraulic feed rate and to hold constant the solids loading rate for incoming residuals that have changing percent solids concentrations. This calls for an equalization/thickening facility prior to the centrifuge itself. If the centrifuge is not to be used for any significant time (24 hours or more), the inside of the bowl needs to be washed down with significant quantities of water. If not washed, the solids remaining in the bowl will dry and possibly cause unbalanced operation.


51

Pressure Filter Press

The basic concept of pressure filtration is the separation of water from a liquid residuals slurry using a positive pressure differential as the driving force. The pressure filter press is also called a pressure filter, plate and frame press, recessed plate press, filter press and (with modification) diaphragm filter press. The pressure filter contains a series of filter plates supported by and contained in a structured frame. The plates are designed such that when two adjacent plates are brought together a compartment/chamber between the plates is formed to hold residuals. The plates are pushed tightly together, by hydraulic or electromechanical means, to make the compartment leakproof.

Lining the compartment is a cloth media which is porous enough to retain the residuals solids while releasing the water in the residuals. While the residuals are being pumped into the compartments, the solids are retained and the water released from the pressure filter press. The residuals pumping continues after the compartments are full (thus pressuring the compartment) until the solids concentration of the cake in the compartment is at an optimum value. Then the pumping is ceased, the plates separated and the retained sludge cake released by gravity for ultimate disposal. The above describes one “cycle’ of pressure filter press. At the end of one cycle the plates can be automatically realigned for loading the next batch of residuals. Proper maintenance of filter plates and media is critical in maintaining the design performance and preventing damage to the plates. Frequent cleaning of the media (perhaps as often as once every 8 to 10 cycles) will improve performance, reduce the time spent manually removing cake “stickers”, and prolong the life of the media and possibly the plates themselves. Plates can be warped or broken if the media are non-uniformly clogged due to the pressure gradients created across the plate. Plate damage may be caused by uneven pressures in a chamber or between adjacent chambers. Media replacement may be required every 1,000- to 4,000-filter cycles.

Belt Filter Press

Belt filter presses use a combination of gravity draining and mechanical pressure to

dewater residuals. A typical belt filter press consists of a chemical conditioning stage, a gravity drainage stage, and a compression dewatering stage (see Figure 5.6). The dewatering process starts after the feed residuals have been properly conditioned, usually with polymer. The slurry enters the gravity drainage stage, where it is evenly distributed onto a moving porous belt. Readily drainable water passes through the belt as the slurry travels over the full length of the dewatering stage. Typically, one or two minutes are necessary to allow for the filtrate separation in the drainage stage.


52

Photo courtesy of Andritz

Figure 5.6 Andritz belt filter press, Waco, Texas, USA

Following gravity drainage, the partially dewatered residuals enter the compression dewatering stage. Here, the residuals are “sandwiched” between two porous cloth media belts which travel in an “S”-shape path over numerous rollers. Both belts operate under a specific tension which induces dewatering pressure into the residuals. The “S”-shape path the residuals follow creates shear forces which assist in the dewatering process. The compressive and shear forces working on the residuals increase over the length of this dewatering stage. The final residuals cake is removed from the belts by blades. Proper residuals conditioning is considered critical for obtaining acceptable dewatering results. A typical residuals conditioning unit consists of chemical conditioner storage, metering pumps, mixing equipment (chemical and chemical/residuals), controls and process piping. In general, polymer is used for chemical conditioning. To achieve proper residuals conditioning, the polymer is first diluted to between 0.25 and 0.50 percent by weight before it is applied to the feed residuals. Next, the residuals and the polymer are thoroughly mixed. The required mixing time depends on residuals characteristics and type of polymer used. The design and selection of a belt filter press is often based on the throughput of the machine, i.e., the rate the residuals can be dewatered by the press. The throughput capacity can be limited either by the water in the residuals (hydraulically) or can be solids limited. A belt filter press having a particular type of belt at a particular width has a maximum loading capacity for a particular residuals. Generally the solids loading is considered the most critical factor and the throughput is expressed in terms of solids loading. The loading units are usually similar to a yield except expressed as belt width, mass/width•time., e.g. lb/hr/meter.


53

Vacuum Filter

In sludge filtration, pressure differential across a filter medium is required to force the water in the sludge through the medium while retaining the solids and ultimately forming a cake. The pressure differential in vacuum filtration is a vacuum applied to the downstream/receiving side of the medium. The best way to express the conceptual theory of a vacuum filter press is the filter yield. The filter yield is defined as the mass of dry cake solids discharged from the filter media per hour per ft2 of filter (e.g., kg/m2•s).

Most vacuum filters employ a rotating drum with filter media on its surface. The drum is partially submerged (10 to 50 percent) in a vat of residuals. The residuals may be agitated to maintain the solids in suspension. The drum revolves around a horizontal axis of rotation. A vacuum applied at the surface of the drum draws the filtrate through the media and cake to the collecting piping. The filtrate flow is controlled by a timing valve located at one end of the drum along the axis of rotation. A complete revolution of the drum is divided into three phases: cake pick-up or formation, cake drying and cake discharge. The cake formation stage takes place while the drum is submerged in the residuals vat. Wet residuals are collected on the filter media by the vacuum applied in the drum’s surface. The cake drying stage begins when the residuals collected on the rotation drum surface leave the vat and are exposed to air. The vacuum is continued and the air drawn through the residuals dewaters and assists in drying. In the cake discharge phase, no vacuum is present and the cake is discharged from the press by various means depending on the type of vacuum press. Washing of the filter media after cake discharge is performed on almost every vacuum filter. This washing removes the solid particles and conditioning agents which could clog the media openings and cause blinding. The washing is usually accomplished with a high pressure spray.


54


55

CHAPTER 6

SPECIAL WASTES

Many small systems will produce residuals that contain arsenic and radioactivity. Because these residuals may be particularly difficult to handle, this chapter specifically addresses those contaminants.

ARSENIC

All water systems must supply finished water with less than 0.01 mg/L arsenic according to the Safe Drinking Water Act, (USEPA 2003b). A number of treatment technologies have been approved by USEPA as Best Available Technologies (BAT) for arsenic removal (Table 2.2). As discussed in Chapter 2, these technologies can produce a number of different types of waste, both solids and liquids.

Table 6.1 shows the options available to dispose of these materials produced by treatment technologies. In general, arsenic in the residual material can limit the options available for disposal. The material must be analyzed for leaching potential using the TCLP procedure (EPA Test Method 1311) (USEPA 1991a). The arsenic in the leachate must not exceed 5 mg/L or it will be categorized as a hazardous waste. Generally, adsorption media will not fail the TCLP because the arsenic is tightly bound, and coagulant sludges generally do not have levels high enough to fail this test. In California, the Waste Extraction Test (WET) is used to determine the toxicity of a material, and so, to determine if the waste must be handled as a hazardous material (State of California 2005). California’s WET procedure is similar to that described in the TCLP, but it uses, more stringent conditions. Therefore, some sludges could pass the TCLP, but fail the WET.

Table 6.1

Summary of residuals and management methods for arsenic treatment technologies Treatment technology Form of residual Type of residual Possible disposal methods

Anion exchange Liquid Regeneration streams Sanitary sewer

-- Spent backwash Direct discharge

-- Spent regenerant Evaporation ponds/lagoon

-- Spent rinse stream

Solid Spent resin Landfill

Hazardous waste landfill

Return to vendor

Activated alumina Liquid Regeneration streams Sanitary sewer

-- Spent backwash Direct discharge

-- Spent regenerant (caustic) Evaporation ponds/lagoon

-- Spent neutralization (acid)

-- Spent rinse

(continued)


56

Table 6.1 (Continued) Treatment technology Form of residual Type of residual Possible disposal methods

Liquid filtrate (when brine streams are precipitated)

Solid Spent alumina Landfill

Hazardous waste landfill

Land application

Sludge (when brine streams are precipitated)

Media adsorpstion Liquid Spent backwash Sanitary sewer

Spent regenerant Direct discharge

Spent rinse stream Evaporation ponds/lagoon

Solid Spent media Landfill or

Solids from backwash Hazardous waste landfill

Iron and manganese removal processes

Liquid

Filter backwash

Direct discharge

Sanitary sewer

Evaporation ponds/lagoons

Solid Sludge (if separated from backwash water)

Sanitary sewer Land application

Landfill

Spent media Landfill

Hazardous landfill

Membrane processes Liquid Brine (reject and backwash streams) Direct discharge Sanitary sewer

Deep well injection

Evaporation ponds/lagoon

Source: SAIC 2000

If the material does fail the TCLP, then it can only be disposed of at a hazardous waste facility. Unfortunately, there are few of these available that will accept small quantities of materials, and the cost to do so is quite high. Transportation to these facilities is also regulated, under the Hazardous Materials Transportation Act. The requirements of this Act covers how the material is packaged, the manifests that must accompany it, and the record keeping that must be done.

It is more feasible for a small system to contract with a service provider to handle spent media, or to arrange with the manufacturer of the media when applicable to remove this material from the facility. In any event, it is important to try to avoid the production of a material that is characterized as hazardous. In some situations, it may be necessary to monitor the media closely, and remove it before sufficient arsenic on the media has adsorbed or has become entrapped to cause it to fail the TCLP. USEPA defined a standard for arsenic in drinking water, with a maximum contaminant level (MCL) for arsenic of 0.01 mg/L. For utilities that need to utilize an arsenic removal treatment technology, it is critical to evaluate the types of residuals that would be generated, their expected arsenic concentrations, and the residuals pre-treatment strategies that would be required


57

prior to final disposal. A utility needs to understand the residuals impacts from removing arsenic in the raw water.

Regulations

Arsenic residuals management methods are classified into two groups depending upon whether they are liquid residuals or solid/sludge residuals. In the case of liquid residuals, disposal methods may include: direct discharge to a water body, indirect discharge via sanitary sewer system, underground injection, management in lagoons, and possible land application. Solid/sludge residuals may be disposed through landfill land application, storage in lagoons, and reactivation, recovery, or disposal of spent resin. As discussed in Chapter 4, federal and state regulations apply to handling, transportation, and disposal of arsenic-laden residuals. Most states have the administrative authority to implement federal regulations, and are then required to establish and administer regulations meeting the requirements of these acts. Waste disposal regulations are primarily the responsibility of the states, but the state regulations must meet or exceed the federal regulations.

Lagoons are not considered an ultimate disposal method for drinking water treatment residuals, because they are not a permanent disposal and will eventually require cleaning and final disposal of the solids (Cornwell et al. 2003). However, many utilities choose to manage some liquid residuals by storing them in lagoons on site, allowing for decantation and some evaporation. If the material stored in these lagoons is non-hazardous, then the management of the lagoons would be regulated by the Safe Drinking Water Act (SDWA.) The requirements of that act specify that states must establish programs to protect wellhead areas; that is, areas around a well or a public water supply wellfield from contaminants that may pose adverse effects on human health.

If the water treatment residual has failed the TCLP test because of arsenic concentrations, then on-site lagoons would be regulated by RCRA. Under RCRA, USEPA has established criteria that prohibit practices that contaminate surface or ground water (40 CFR 257) and also established comprehensive design and operation standards applicable to surface impoundments (USEPA 1991b).

Liquid residuals can be disposed of by:

• Direct discharge (NPDES permit limits) • Indirect discharge (POTW pre-treatment limits) • Underground injection (UIC Program) • Beneficial use (RCRA)

Solids residuals are typically disposed of by:

• Landfilling (RCRA) • Beneficial use (RCRA) • Return to the vendor


58

Processes Several drinking water treatment technologies are used for removal of arsenic from water supplies. Conventional coagulation with alum or iron salts followed by filtration removes arsenic (Chen et al. 1994 and Sorg 1993). Lime softening and iron removal are conventional treatment processes that can potentially remove arsenic from source waters. Ion exchange (IX) and active alumina (AA) adsorption are able to remove arsenic and result in sludge-free operations. Iron-based adsorption media, such as granular ferric hydroxide, have demonstrated high arsenic removal capacities. Other technologies for arsenic removal include manganese greensand, reverse osmosis, electrodialysis reversal (EDR), nanofiltration, and adsorption on activated carbon. Drinking water treatment processes for arsenic removal generate residuals containing arsenic and/or other contaminants removed from raw water. The treatment processes most frequently used for arsenic removal were presented in Table 6.1. These processes are generally described in Chapter 2, but their use for arsenic is described here.

Ion Exchange (Regenerable)

To remove arsenic from drinking water, water is passed through one or more chloride-form strong-base anion-exchange resin beds. Arsenate ions are preferentially removed according to the order of preference for exchange. Ion exchange does not remove As(III) because As(III) occurs predominantly as an uncharged ion (H3AsO3) in water with a pH value of less than 9.0 (Clifford 1999). If As(III) is present, it is necessary to oxidize As(III) to As(V) before removal by IX. When all available sites on the resin have been exhausted, the bed is regenerated with a brine solution (chloride exchange). The efficiency of the IX process for arsenic removal is strongly affected by competing ions, such as total dissolved solids (TDS) and sulfate (Clifford 1999). Other factors affecting the use of the IX process include empty bed contact time (EBCT) and spent regenerant disposal. Regeneration steps include resin backwashing, brine regeneration, and a final rinse to remove the brine water. All three regeneration waste streams are usually blended together for final disposal (Figure 6.1).


59

Source: MacPhee et al. 2001

Figure 6.1 Schematic of ion exchange process with regeneration for arsenic removal

Membrane Filtration Both nanofiltration (NF) and reverse osmosis (RO) processes can remove trace inorganic contaminants such as dissolved arsenic (USEPA 2000). A simplified schematic of membrane filtration is presented in Figure 6.2. The removal efficiency for RO is typically 95 percent for arsenic. As membrane pore size decreases, so does the recovery rate of treated water. These membrane processes generate two streams: the permeate (product water) and the concentrate (waste stream). The concentrate can be high in total dissolved solids depending on the raw water characterization. Concentrate discharge is subject to the disposal requirements under CWA and RCRA.


Figure 6.2 Schematic of membrane process for arsenic removal

Concentrate

Permeate

Membranefiltration

High pressure feed pump

Pre-filtration

Acid/antiscalantpre-treatment

Feed water

S p e n t b a c kw a sh /r in s e

S p e n t re g e n e ra n t (b r in e )

P ro d u c t/ t re a te d w a te r

B a c kw a sh /r in s e

R e g e n e ra n t b r in e s o lu t io n

O x id iz in g P re -F ilte r

R aw w a te r s o u rc e

A n io n E x c h a n g e R e s in


60

Activated Alumina

Activated alumina (AA) will remove a variety of contaminants, including arsenic. Alumina adsorption is specific for arsenate As(V). In order to achieve effective removal of arsenic from raw water by means of columns, arsenite must be oxidized to As(V) through an oxidative pretreatment ahead of activated alumina columns operated at an optimum pH of 6.0. The capacity of alumina is significantly reduced in the presence of sulfate ions, but only slightly affected by chloride, suggesting that HCl rather than H2SO4 would be preferred for pH adjustment. Alumina particle size and empty-bed contact time impact arsenic removal. Finer particles of alumina (28 x 48 mesh, 0.6 to 3 mm) have higher arsenic capacity, lower arsenic leakage and longer run length than larger alumina particles (14 x 28 mesh, 1.18 to 0.6 mm) (Clifford and Lin 1991, Simms and Azizian 1997). To minimize bed size and alumina inventory, operation is run for a 3- to 6- min EBCT range. Activated alumina systems can operate using either media replacement after exhaustion or on-site regeneration. Arsenic is difficult to remove from alumina and only 50 to 70 percent of the adsorbed arsenic is eluded during regeneration, and the arsenic capacity of the alumina decreases by 10 to 15 percent on each subsequent run (Clifford and Lin 1986, Clifford and Lin 1991). During regeneration and acidification of spent alumina, enough aluminum dissolves to make precipitation of Al(OH)3(s) a feasible treatment step for the removal of arsenic from spent regenerant wastewater. A process schematic for a full-scale activated alumina water treatment system is shown in Figure 6.3. Source: MacPhee et al. 2001

Figure 6.3 Schematic of AA adsorption process with regeneration for arsenic removal

Activated Alumina

Raw water source

Chlorine

Sulfuric acid

Rinse water

Wastewater:

Spent backwashSpent regenerant sodium hydroxide

Product water

Wastewater:

Spent acidSpent rinse

Sodium hydroxide regenerant solution

Backwash water


61

Liquid and/or solid residual may be produced from an AA process system depending on the type of operation (USEPA 2000a). If the system is regenerated, a liquid waste is produced from backwash, caustic regeneration, neutralization, and rinse steps. Sludge may also be generated from regeneration and neutralization streams because some alumina dissolves during the regeneration step and may be precipitated as aluminum hydroxide (AWWA 1990). If an aluminum-based sludge is produced from lowering the pH of the liquid residual, this sludge will contain a high amount of arsenic because of its arsenic adsorption characteristics. This sludge and the remaining liquid fraction of the solution will require disposal. Because both residuals contain arsenic, their disposal may be subject to CWA and RCRA disposal requirements. Because the AA media will filter out particulate material in the source water, the media bed will occasionally require backwashing. This backwash water will likely contain some arsenic attached to either the particulate material or the very fine AA material that is removed during backwashing. Consequently, the disposal of the backwash water may also be subject to the disposal requirements under the CWA and RCRA. When operated on a throw-away basis, the exhausted AA media will be the principal residual produced. This media has the potential of being classified as a hazardous waste because of its high arsenic content. A TCLP test is necessary, therefore, to determine its classification and ultimate disposal restrictions. For throwaway systems, the need for backwash to mitigate headloss accumulation from trapped particles generally coincides with media exhaustion and as such backwash streams are rare when the throwaway option is used.

Iron-Based Sorbents (IBS)

Media is available that uses an adsorption process for arsenic and other heavy metals removal from raw water supply. Raw water is passed through the media to remove contaminants. The process utilizes a ferric-based, non-regenerative media to absorb arsenic onto the media. The adsorption life of the media is determined by raw water pH, arsenic concentration levels, arsenic oxidation state, and operating cycles per day. These are non-regenerative media and are operated as a fixed bed adsorber. Typical installation in pressure vessels allows a single pumping stage for the water treatment system. The vessels are arranged in parallel or series arrangement depending on water parameters and required removal concentrations with an empty bed contact time of around five minutes. If a consistent 90 percent reduction is needed across the system, series design is used, while if the percentage is less than 90, then the parallel design is typically applied. Pressure vessels include an overdrain system for distribution of influent water and collection of backwash waste, and an underdrain system for collection of treated water and distribution of backwash water. Iron based media is placed on a gravel support bed of 12-in. depth. Standard hydraulic loading rate is 5 to 8 gpm/ft2 with a total empty bed contact time (EBCT) of five minutes. Backwash supply water is provided by the in-service vessels or by return from the system. The vessels are backwashed once every two to six weeks to prevent bed compaction and remove trapped particulates. Once the media is exhausted, it is removed from the vessels and new media is installed. Iron-based sorbents have greater arsenic adsorption capacity than AA and therefore backwashing to remove headloss-causing particles is often necessary before the sorbent is exhausted. Hence two types of residuals are regenerated: spent media and spent backwash (USEPA 2000). The spent media can generally be landfilled as non-hazardous waste according


62

to TCLP or California WET results, while the spent backwash requires treatment prior to final disposal. The spent backwash usually contains high levels of particles, some of which may be carried over from the sorbent. These solids can contain arsenic at levels that would prohibit their release to streams or land. Backwashing does not release soluble arsenic, but since raw water is often used as the backwash water, the level of dissolved arsenic in the spent backwash corresponds to the dissolved arsenic level in the raw water. Production of a spent backwash water can be avoided by the use of a prefilter (Min et al. 2004). Min et al. studied the use of cartridge filters placed before the adsorbent columns and found that using this process, particulate matter was removed, and the need for frequent backwashing of the adsorbent columns was minimized.

Iron-Manganese Removal Systems Because arsenic, particularly arsenate, is readily adsorbed onto iron hydroxide, iron/manganese removal processes are effective for arsenic removal. A schematic of air oxidation-filtration iron and manganese removal water treatment process is presented in Figure 6.4. The oxidation step converts soluble iron (ferrous) into the insoluble form (ferric) that is then removed by the filtration process, usually by a granular media. Because air oxidation is not normally effective for oxidizing As(III) to As(V), chlorine may be required on source waters that contain As(III). When the filtration media reaches its filtering capacity, the media is backwashed producing a liquid residual (spent filter backwash water) for disposal.

Source: USEPA 2000

Figure 6.4 Schematic of oxidation-filtration iron and manganese removal process for

arsenic removal

Raw

waterAeration

Cl2

Filtration

Filter

backwash

water

Finished water


63


Figure 6.5 Schematic of iron and manganese (greensand) filtration process for arsenic

removal

The use of potassium permanganate, in conjunction with a manganese greensand filter, is

also a widely used technology for removing arsenic from water. A simplified schematic of a greensand filtration process is presented in Figure 6.5. Potassium permanganate can be fed continuously ahead of the filter to oxidize As(III) to As(V) plus iron and manganese which are then adsorbed on greensand. The potassium permanganate also regenerates manganese greensand. Alternatively, the bed of greensand may be activated intermittently with permanganate to form an active coating of manganese dioxide. Because arsenic removal is due to adsorption onto the iron, the capacity for arsenic removal is dependent on the concentration of iron in the source water. Greensand filters require periodic backwashing to remove excess solids. Backwashing is accomplished by reversing the flow of water through the filter bed to flush out particulates. The backwash waste contains elevated concentrations of Fe and Mn as well as other contaminants (MacPhee et al. 2001).

Coagulation Microfiltration, Conventional Treatment, Lime Softening

Coagulation using alum and iron (III) salts can be used to remove dissolved arsenic. Removal mechanisms for dissolved inorganics consist of two primary mechanisms: adsorption and occlusion. During the adsorption process, the dissolved contaminant attaches to the surface of a particle or precipitate. Occlusion occurs when the dissolved contaminant is adsorbed to a particle and then entrapped as the particle continues to agglomerate. Several factors affect the coagulation process, including coagulant dosage, pH, turbidity, natural organic mater (NOM), anions and cations in solution, zeta potential, and temperature. Arsenic removal is directly correlated with coagulant dosage, and turbidity removal is a prerequisite for arsenic removal. Coagulation followed by filtration (CF) is effective for arsenic removal when the coagulant dose (usually iron) are low enough to allow for direct filtration.

Feed water

Feed pump

Oxidant

Backwash/rinsewater

Finished water

Backwash/rinse(spent waste with Fe and Mn)

Greensand Media Filter


64

Lime softening can be effective for removal of heavy metals, radionuclides, dissolved organics, and viruses through adsorption and occlusion with calcium carbonate and magnesium hydroxide. Lime softening is very effective at arsenic removal. Coagulation-microfiltration (CMF) is the same approach as conventional treatment, except that the sedimentation and filtration step take place in a single stage: the microfiltration (MF) membrane system. CMF, conventional treatment using granular media filtration, and lime softening systems each generate a liquid residual for disposal. The CMF process would generate a backwash stream, while conventional and lime softening would generate spent filer backwash water (SFBW) and settled solids blowdown from clarification.

Residuals Quantities and Characteristics

Table 6.2 provides a summary of example arsenic concentrations in water treatment residuals (Amy et al. 2000). The residuals volumes and arsenic concentrations shown in the table for various types of residuals were calculated assuming a raw water arsenic content and arsenic removal for each treatment technology. Arsenic concentrations in residuals volumes generated in processes listed in Table 6.2 ranged from 0.098 mg/L for membrane technologies to approximately 10 mg/L for activated alumina and ion exchange. On a dry weight basis, theoretical arsenic concentrations ranged from 165 to more than 14,000 mg/kg.

Table 6.2

Summary of example residuals quantity from arsenic processes

Treatment technology

Volume of

residuals produced (gal/MG)

As concentration in residuals

volume (mg/L)

Quantity of

solids produced (lb/MG)

As concentration in solids (mg/kg

dry weight)

Conventional coagulation

4,300 9.25 180 1,850

Softening 9,600 4.2 2,000 165

Ion exchange 4,000 10 5.2 14,250

Activated alumina 4,200 9.52 23.4 (calculated)

14,250 (calculated)

Iron-based sorbents 21,000 1.9 23.4 (calculated)

14,250 (calculated)

NF/RO 664,000 0.098 NA NA

Coagulation/MF 52,600 0.76 112.6 2,957

Source: Amy et al. 2000 NA = Not applicable lb/MG x 0.12 = kg/ML


65

Table 6.3 shows a summary of the key water quality results obtained in USEPA (2000) for residuals samples collected from various arsenic treatment techniques. Results showed that about 99 percent of the arsenic in the ion exchange regenerant samples was in the dissolved form. Almost none of the arsenic in the AA regenerant stream and the spent filter backwash water (SFBW) samples was dissolved. The concentrate samples collected from the RO and NF plants had very low arsenic concentration. Arsenic levels in the residuals streams were compared to corresponding source water arsenic levels to determine the “concentration factor,” or the degree to which arsenic levels were concentrated in the residuals by the various treatment processes, as shown in Table 6.4. Arsenic concentrations reached as high as 10 and 25 mg/L in the ion exchange regenerant streams. The spent filter backwash water, (A) and spent filter backwash water and adsorption clarifier flush (ACF), blend (B) had total arsenic levels of about 1.5 mg/L. Total arsenic in the AA regenerant stream was 2.6 mg/L. Concentration factors for the SFBW and SFBW/ACF samples were 61 and 12, respectively. Arsenic concentration for AA regenerant stream was comparable, with a concentration factor of 44. The highest concentration of arsenic occurred in the ion exchange waste streams. Arsenic levels were 270 and 236 times greater than the corresponding source water arsenic concentrations for the composite waste streams (brine, backwash, and rinse waters) tested. Arsenic concentration was greater for brine streams than the blends. Clifford et al. (1998) reported also that arsenic was concentrated by a factor of 144 in the brine.

Table 6.3

Arsenic residuals sample characterization

Untreated residuals characteristics

Sample type

pH

Alk*

Total

hardness

TDS

(mg/L)

Total As

(mg/L)

Dissolved As (mg/L)

Total Fe (mg/L)

Total Mn (mg/L)

Conduc-tivity

( S/cm)

Sulfate (mg/L)

AA regenerant 7.1 268 13 10,240 2.63 0.12 0.83 0.09 22,640 16,338

SFBW (A) 7.6 430 365 460 1.41 <0.002 78.5 7.52 900 4.82

SFBW/ ACF (B) 8.1 197 400 341 1.74 0.03 45.9 3.75 680 97.3

RO (A) 7.9 2,800 460 14,300 <0.002 <0.002 0.65 0.23 28,500 544

RO (B) 7.3 600 840 11,750 <0.002 <0.002 0.86 1.1 1 23,800 --

NF (A) 7.1 325 1,560 1,765 0.013 0.007 2.16 0.14 3,515 1,075

NF (B) 6.6 210 1,750 1,533 0.005 0.009 0.46 0.08 3,080 1,190

Ion Ex (B) 9.7 7,000 86 6,240 24.8 24.7 <0.01 <0.005 8,100 910

Ion Ex (A) 9.0 950 90 4,100 10.5 10.3 0.49 -- 12,440 --

Source: Adapted from USEPA 2000a *mg/L as CaCO3


66

Table 6.4 Concentration of arsenic in residuals

Arsenic concentration (mg/L)

Sample type Source water Residuals stream Concentration factor

Ion Ex (A) 0.039 10.5 270

Ion Ex (B) 0.105 24.8 236

SFBW(A) 0.023 1.41 61

SFBW/ ACF 0.149 1.74 12

AA regenerant 0.060 2.63 44

Source: Adapted from USEPA 2000a

Treatment of Arsenic −−−− Containing Liquid Residuals Liquid wastes from arsenic removal processes often have arsenic levels higher than allowed for discharge to streams or land. In this case the arsenic must be removed prior to discharge. Figure 6.6 illustrates some of the possible treatment processes for brines generated from AA and IX regenerants as well as for concentrates from NF and RO. The treatment processes for the liquid wastes are essentially the same as for treatment of the source water: either adsorption, exchange, or precipitation. Extensive testing has been done to identify methods to treat these arsenic residuals (USEPA 2000a, MacPhee 2001).

A summary of the best treatment technology determined for each residual type is presented in Table 6.5. Three residuals streams (AA regenerant, Ion Ex (A), and Ion Ex (B)) could not be treated below the common SPDES total arsenic concentration limit of 0.05 mg/L. The results show that overall, the iron-based coagulant and adsorption media resulted in greater arsenic reductions than the aluminum-based coagulant and adsorption media. In general, all of these liquids were difficult to treat. Unless a sewer is available that can accept the residuals without treatment, production of liquid residuals is best avoided.


67

Source: Adapted from USEPA 2000a

Figure 6.6 Arsenic residuals treatment options

Table 6.5

Summary of treatment results for removing arsenic from liquid arsenic waste

Sample type

Best treatment conditions determined from testing*

Total As remaining (mg/L)

AA regenerant None 0.154

Ion Ex (A) None 1.28

Ion Ex (B) None 18.7

RO (A) Ferric chloride precipitation 0.041

RO (B) Iron media adsorption 0.018

NF (A) Ferric chloride precipitation, iron-based media or AA adsorption

0.009, 0.030

(continued)

Ion exchange brine

AA regenerant

RO concentrate

NF concentrate

SFBW from Fe removal plant

and blend of SFBW and adsorption clarifier flush

Precipitation

Adsorption

exchange

Alum

Ferric

Liquid residuals

Solids/sludge residuals

Residuals

Fe-based media

AA media

Anion exchange

resin

Modified alumina

pH adjust

Arsenic Residuals Stream Residuals Treatment Process


68


Sample type

Best treatment conditions determined from testing*

Total As remaining (mg/L)

NF (B) Iron media adsorption, ferric chloride precipitation <0.002, 0.005

SFBW (A) (settled)

Ferric chloride precipitation 0.013

SFBW/ACF (B) (unsettled)

Gravity settling (no chemical addition) 0.043

(settled) Iron media, ion exchange, or AA adsorption <0.002

Source: Adapted from MacPhee et al. 2001 *Goal was to reach 0.05 m/L arsenic which is the discharge standard for many states

Spent Backwash From Iron-Based Sorbents Iron-based adsorption columns periodically require backwashing. Frequency varies significantly based on source water quality and system design, but typically these columns are backwashed every few weeks, or months. The SFBW can contain dissolved arsenic if raw water is used to backwash. SFBW can also contain particulate matter that can have arsenic associated with it. The particulate matter is from the source water or media. This SFBW can, therefore, contain high levels of total arsenic, requiring its proper disposal. Methods can be put into place that minimize the production of SFBW. Alternatively the SFBW can be treated to remove the solids. Prefiltration before an iron based adsorbent system that removes arsenic can be beneficial to the performance of the adsorber system. A recent Water Research Foundation study looked at the use of small cartridge filters for this purpose (Min et al. 2004). The study found that cartridge filters placed before the sorbents (i.e., as prefiltration) did not absorb soluble arsenic, and that particulate arsenic, which was partially retained by cartridge filters, stemmed from arsenic absorption onto iron particles. This would mean that disposal of cartridge filters in a landfill may not be difficult, depending on the TCLP and/or WET results for systems located in California. Another practice that may be of value is that of treating the backwash stream itself. The spent backwash is typically highly turbid because of sorbent particles carryover, and contains elevated total iron concentrations. The high turbidity from the spent backwash would saturate the cartridge filters employed for prefiltration prior to recycle. As such, an alternative backwash treatment technique, such as coagulation-sedimentation, would be more appropriate. Additionally, it would also contribute to a further decrease in total arsenic concentration in the treated backwash compared to a filtration technique. However, the coagulation-sedimentation technique is more operator-intensive than cartridge or bag filtration, implies high capital costs for utilities without such existing facilities, and requires further treatment of generated residuals, especially if tests indicate arsenic leaching beyond the regulatory limit (Min et al. 2004). If significant amounts of particulate arsenic pass through the spent backwash treatment step, the mixed influent (i.e., the combination of raw water and recycle streams) will be affected. This is important since each backwash recycle event could


69

significantly increase the total arsenic concentration in the sorbent effluent because of arsenic accumulation in the influent. The best action is to dispose of backwash water in a sewer if possible, or avoid its production by using a prefiltration step.

Summary of Options to Remove Arsenic from Liquid Residuals Figure 6.7 illustrates the decision process used to determine the method to remove suspended or dissolved arsenic from the liquid residuals and to concentrate the arsenic in solid form. Generation of a more concentrated solid will then occur. If a utility elects not to remove arsenic from the liquid residuals, the only other option would be to dewater the residuals in an evaporation lagoon. An evaporation lagoon would only be practical for utilities generating small volumes of liquid residuals due to the large land footprint required for drying. In the schematic, it is assumed that only AA, IX, RO and NF processes could potentially use the evaporation lagoon process, due to the typically low volumes of residuals generated and lower concentrations of suspended solids present.

Note: Spent media disposed of in non-hazardous waste landfill

AA and iron-based media adsorption backwash waters expected to meet POTW direct discharge or recycle arsenic criteria

Liquid residual As levelprohibit discharge or recycle/reuse?

Conventional treatmentLime softening

Mn greensand filtrationCMF

Remove As from SFBW or blowdown

w/o chemical

Coagulant

and clarification or

adsorption

Polymer

and clarification

for As removal

Clarification

Thickening/dewatering

Direct discharge*

(<0.05 mg/L)Recycle/reuse

POTW discharge*

(0.05 - 1 mg/L)Non-hazardous

landfillHazardous waste

landfill

No pretreatment

Treatment type?

Solids pass TCLP or Ca WET

for As?

Disposable AA

Fe-based media adsorption

Yes

No

Solids

Liquid decant

Solids

Liquid decant

Yes

No

Yes

No

IXRO/NF

Source: Adapted from Cornwell et al. 2003 *Numbers are examples. These limits are typically site specific, set by the state.

Figure 6.7 Arsenic residuals handling and disposal decision tree


70

Handling of Solids From Arsenic Removal

As discussed above, several solid residuals can be produced by arsenic removal systems. Spent exhausted media can be produced by AA and IBS systems. Generally a contract can be established for the media vendor to take back the spent material. They will often supply replacement material at a cost less than normal. If the media cannot be returned to the vendor, then it needs to undergo TCLP or WET (for systems in California) testing and be properly disposed of. Other solids produced can be coagulant solids from treating liquid residuals or coagulant solids from treatment processes removing arsenic from the raw water such as CF or CMF. These residuals can either: go to a sewer, be dewatered and disposed of, or be stored in a lagoon. Options for dewatering these residuals were discussed in Chapter 5, and disposal is discussed in Chapters 7 to 10.

RADIOACTIVITY

The revised Radionuclides Rule came into effect on December 8, 2003, mandating that all community water systems (CWSs) come into compliance with this regulation. This rule retained the maximum contaminant levels (MCLs) for combined radium-226/228, gross alpha particle activity and combined beta particle and photon radioactivity. The Rule also revised and added to existing requirements, and set a new MCL for uranium, as shown in Table 6.6.

Table 6.6

Radionuclides MCLs

Combined radium -226 and 228 5 pCi/L

Gross alpha particle activity (excluding radon and uranium) 15 pCi/L

Beta particle and photon radioactivity 4 mrem/year

Uranium 30 :g/L

Residuals Production

Systems can use a number of treatment alternatives to come into compliance with this regulation. BATs and the resulting residuals are shown in Table 6.7.

Treating water for naturally occurring radionuclides will result in residual streams that are classified as “technologically enhanced naturally occurring radioactive materials,” or TENORM. TENORM is defined here as naturally occurring materials, such as rocks, minerals, soils, and water whose radionuclide concentrations or potential for exposure to humans or the environment is enhanced as a result of human activities (e.g., water treatment).

For more information on the Radionuclides Rule, go to:

www.epa.gov/safewater/radionuc.html


71

Table 6.7

Summary of treatment technologies for removal of naturally occurring

radionuclides in water*

Treatment technology Contaminant

removed Removal efficiency

(percent) Wastes produced Waste concentrations

Cation exchange Radium 85 - 97 Rinse and backwash water Regenerant brine

8 to 9 pCi/L-RaH

50 to 3,500 pCi/L- RaH

22 to 94 pCi/LI

Anion exchange Uranium 95 Rinse and backwash water Brine regenerant solution

2 to 6e+06 pCi/LH-U

35 to 4.5e+06 pCi/LH-U

1.3 to 11 pCi/LI

Lime softening Raium Uranium

90

85 – 90'

Sludge (at clarifier) Sludge (dry) Filter backwash

76 to 4,577 pCi/L-Ra 1 to 21.6 pCi/g-Ra 1 to 10 pCi/g-U

6.3 to 21.9 pCi/L-Ra

Reverse osmosis Radium Uranium

90+ -ND

Reject water 7 to 43 pCi/L-Ra 200 to 750 pCi/L-U

Electrodialysis Radium Uranium

90 ND

Reject water No data

Iron removal Oxidation Greensand

Radium 0 to 70** Solids and supernatant from filtration backwash Green sand media

12 to 1,980 pCi/L-Ra

28 to 250 pCi/g-Ra

Selective sorbents Radium Uranium

90+ Selective sorbents (radium selective and activated alumina)

Up to 3.6 pCi/g-Ra

Coagulation / Filtration

Uranium 50 to 85 Sludge 10,000 to 30,000 pCi/L-U

Source: USEPA 2005a *Data extracted from USEPA 1982, 1986, 1994, 1995; Wade Miller Associates 1991; and Reid 1985 HPeak values IAverage for given waste forms 'May be increased to 99 percent by the presence or addition of magnesium carbonate to the water **May be increased to 90 percent by passing the water through a detention tank after the addition of potassium permanganate prior to filtration ND = No data available

The residuals produced by specific treatments were discussed in Chapter 2. Here, the

specific concerns relating to radioactivity are addressed (from USEPA 2005a).

Ion Exchange

Ion exchange is a BAT for radium, uranium, and beta particle and photon activity removal. Anion exchange (AX) resins remove uranium; cation exchange (CX) resins remove radium and soften water. Mixed bed IX is suitable for beta particle and photon activity removal. AX removes up to 95 percent of uranium; CX removes up to 97 percent of radium. Backwash water, brine (volume varies according to raw water quality, unit size, regenerant concentration and media capacity), and rinse water are produced, as well as spent resins.


72

Radionuclides may become so concentrated in the brine and resin that they may require special handling and disposal procedures. The exact concentration of radium in the waste will vary significantly from plant to plant depending upon the regeneration practices. Generally, for a given radium concentration, as the hardness decreases, the radium concentration in the waste increases. This is because less waste volume per kg of hardness removed is produced as the hardness decreases.

Reverse Osmosis

Reverse Osmosis (RO) is listed as a BAT for radium, uranium, gross alpha particle activity, and beta particle and photon activity and is also effective at removing other inorganic contaminants, such as heavy metals. RO can remove at least 90 percent of these radionuclides from drinking water. Residuals produced can have very high concentrations of the contaminants removed from the water, including radionuclides, which may limit disposal options. The concentration depends on the efficiency of the RO unit. Highly efficient units will produce low volumes of residual streams with high concentrations of contaminants while lower efficiency units will produce higher volumes of residual streams with lower concentrations of contaminants.

Lime Softening

Lime softening is listed as a BAT for the removal of radium and uranium from drinking water. Its removal efficiency depends on the pH of the influent water. Seventy-five to 90 percent of radium can be removed from water with pH levels above 10; the pH range for radium removal is 9.5 to 11.0. Uranium removal can be as low as 16 percent and as high as 97 percent. The process produces spent filter backwash waters containing radium, uranium, particulates, and co-occurring contaminants. It also produces spent filter media and lime sludge containing high concentrations of radium, uranium, and co-occurring contaminants. Because of the high concentrations of co-occurring contaminants, the sludge may require special disposal. Radium is removed by lime softening and the removal rate increases as the percentage of hardness removed increases. Since radium is associated with sludge solids, its concentration in the liquid stream is a function of the solids concentration. Backwash water concentrations for Radium-226 are also associated with the solids so Radium-226 could be settled into a sludge waste.

Greensand Filtration

Greensand filtration is listed as a Small Systems Compliance Technology (SSCT) for radium removal for systems serving 25 to 10,000 customers. Green sand has shown removal efficiencies ranging from 19 percent to 63 percent for radium-226 removal and 23 percent to 82 percent for radium-228 removal. High concentrations of manganese in an oxidization state increase the efficiency of radium adsorption; high concentrations of manganese in an unoxidized state or iron in the ferric state limit the efficiency of adsorption. This process produces spent filter backwash containing radium, particulates, and co-occurring contaminants as well as spent filter media and sludge.


73

Activated Alumina

AA is listed as a SSCT for uranium removal for systems serving 25 to 10,000 customers. AA may remove up to 99 percent of uranium in drinking water. It produces spent brine, whose volume varies according to raw water quality, unit size, regenerant concentration and media capacity, rinse water, backwash, and acid neutralization. It also produces spent media. AA has a higher affinity for other contaminants, such as arsenate, fluoride, and sulfate. The technology is very pH sensitive. Special disposal procedures may be required for media that can no longer be regenerated, particularly if the media has not been regenerated before removal.

Coagulation/Filtration Coagulation/filtration is listed as a BAT for uranium removal. The efficiency of uranium removal depends on water pH, the prevailing charge on the floc, and the types and amount of uranium present in the water. Uranium removal efficiencies of 85 percent to 95 percent have been observed at pH levels of 6.0 and 10.0. The process results in spent filter backwash water, filter-to-waste (if practiced), sludge, and spent filter media.

GAC

GAC can be used to remove radioactive materials from source water. Granular activated carbon (GAC) removes radon from water by two processes: adsorption and decay. During the initial stage of operation radon is adsorbed onto the carbon, and this process is the predominant one for the first two weeks of operation. After this time, the radon achieves a steady state in which the rate of radon adsorption is approximately equal to the radon decay. Because of the constant radon decay, radon can be indefinitely removed by GAC. Radon decays to its progeny, including Pb-210 and Bi-214, which have varying half-lives and emit different types of radioactive particles. The half-lives of the progeny are relatively short until the decay series reaches the product Pb-210. This material has a half-life of 22 years. Most of the Pb-210, therefore, will remain for the life of the GAC contactor. It is this constant generation of the beta-particle-emitting Pb-210 material that has caused concern. If the radioactivity builds above 2,000 pCi/g, then transportation requirements for radioactive wastes govern and some states may require disposal of the GAC in a low-level radioactive waste facility. Cornwell et al. (1999) conducted pilot studies to evaluate the build-up of Pb-210, uranium, and radium on GAC when used for radon removal. A New Hampshire water tested had a radon concentration of between 10,000 and 20,000 pCi/L and an influent iron concentration of 2 to 4 mg/L. Raw water uranium concentrations were 4.2 to 9.0 pCi/L and the influent radium varied between 0.03 and 0.87 pCi/L. Primarily due to the iron build-up on the GAC, the contactors had to be periodically backwashed. The spent backwash water contained approximately 200 pCi Uranium-258 per gram of dry weight backwash residuals. Uranium concentrations at this level could be a disposal concern. Radium is generally poorly adsorbed by GAC. However, radium can be adsorbed by iron precipitates and therefore, due to the high iron accumulation in the GAC contactors, radium buildup also occurred in the contactors. The backwash water contained 50 to 60 pCi/L radium


74

per gram of dry weight backwash residual. The decay product Pb-210, was also found in the spent backwash, in this case at levels of 350 pCi/g. Due to the presence of radioactivity in the backwash water, removal of the iron prior to the GAC contactor would eliminate the need to backwash the contactors and thereby eliminate this residual. Pb-210 buildup is directly a function of the amount of radon removal. Therefore, the longer the GAC stays in service, the higher the Pb-210 levels will be. The increase will not be technically linear due to the decay of Pb-210. Water system operations using GAC for radon removal or for removal of other contaminants from radon-containing water might be able to minimize the potential for carbon to become characterized as low-level radioactive waste. Because of the problems associated with disposing of this type of waste, systems operators should consider operational modifications that can reduce the concentration of radioactivity. A predictive method is described in McTigue, 1994 that estimates the level of Pb-210 buildup based on influent radon concentration. Using it, a system operator can judge if the carbon needed to remove radon will accumulate Pb-210 above a regulatory threshold. It may be economically prudent to remove the carbon for disposal before reaching this limit. Even though the carbon may still have capacity for radon removal it will probably be more economical to replace the carbon “prematurely” than to dispose of it as a radioactive waste. Similarly, an operator can use more GAC than specified by the EBCT, thereby lowering the total Pb-210 radioactivity concentration per gram of carbon. Again, this practice would entail an increase in capital costs for the system, but the overall cost of the system may be lower than paying for the disposal of spent GAC in a specialized landfill. A utility may also consider lowering the radon to a level higher than the limit and then blending this water with a radon-free source. If feasible, this option would reduce the amount of radioactivity that would end up on the GAC.

Table 6.8

SPARRC elements

Technology Radionuclides Co-Contaminant

Coagulation/Filtration Uranium Arsenic

Lime softening Radium and uranium None

IX Radium, barium, and uranium None

RO Radium and uranium None

AA Uranium Arsenic

Greensand filtration Radium and barium None

Source: USEPA 2005a

Characterization

USEPA has developed a Software Program to Ascertain Radionuclides Residuals Concentration (SPARRC) model that indicates potential concentrations of radioactivity in residuals and filters at water system. The current version of SPAARC incorporates predictive algorithms to estimate radionuclides and co-contaminant removals, and focuses on a sound


75

estimate of residual radionuclides concentrations and co-occurring pollutants rather than sizing and designing drinking water treatment technologies. The program allows the operator to select the type of treatment process, as well as input and output parameters such as water flows, doses of coagulant and polymer, and filter capacities. Table 6.8 shows the processes considered. The current version of SPARRC is available at http://www.npdespermits.com/sparrc.

Regulations No federal agency currently has the legislative authority to regulate the disposal of wastes generated by water treatment facilities on the basis of the residuals’ naturally-occurring radionuclide content. The U.S. Nuclear Regulatory Commission (USNRC) regulates licensed radionuclide materials such as would be generated from a nuclear power plant. The Atomic Energy Act (AEA) of 1954 and its subsequent amendments provided the legislative authority for this agency to do so. The USNRC regulates the handling and disposal of both high-level and low-level radioactive wastes that are generated by various man-made processes. High-level radioactive waste includes such things as spent fuel rods from nuclear power plants. Low-level radioactive waste includes such things as clothing and building materials used in nuclear processes. The regulations governing both high-level and low-level radioactive wastes deal only with man-made radioactivity and source material. Uranium and thorium are considered “source material” (42 USC 2014(z)) and so are subject to NRC or Agreement State licensing and regulation. Water treatment systems that produce residuals containing uranium or thorium must comply with this licensing requirement. However, source material of an “unimportant quantity” (10 CFR 40.13) is exempt from NRC or Agreement State regulation if the uranium or thorium makes up less than 0.05 percent by weight (or approximately 335 pCi/g for natural uranium) of the material. These limits apply to both liquid and solid residuals. For perspective, in a system with filter media weighing 30,000 pounds, 0.05 percent by weight would be equal to 15 pounds of uranium. Systems should contact their state agency to determine if their systems require licensing. No federal agency has the specific legislative authority to regulate the handling and disposal of naturally-occurring radioactive material (NORM) such as radium and uranium. This type of regulation was left up to the states, and some states do address the disposal of wastes containing certain naturally-occurring isotopes. The USEPA regulates the disposal of hazardous solid waste under the Resource Conservation and Recovery Act (RCRA). But radioactivity in solid wastes is not one of the classifications used by RCRA to determine if a particular substance is “hazardous.” Activated carbons and sludges from water treatment could not be categorized as hazardous under RCRA because of radionuclide activity. No other federal law specifically regulates disposal of waste containing elevated levels of naturally-occurring radioactive materials at this time. In the absence of regulations, USEPA has developed guidance documents to assist utilities properly dispose residuals containing radioactive materials. USEPA recognizes that naturally occurring radioactive material in wastes is not regulated elsewhere and not all states have established regulations. Three publications, available on the internet from www.epa.gov/safewater/radionuclides/ compliancehelp.html, summarize information currently available on this topic. Much of the information in this chapter was taken from the following publications:


76

“A Regulator’s Guide to the Management of Radioactive Residuals from Drinking Water Treatment Technologies” (USEPA 2005a) “A System’s Guide to the Management of Radioactive Residuals from Drinking Water Treatment Technologies” (USEPA 2000b) “Radionuclides in Drinking Water: A Small Entity Compliance Guide” (USEPA 2002)

State TENORM Regulations

Most states do not specifically regulate water plant wastes on the basis of elevated levels of radioactivity. A few states have enacted restrictions on the disposal of solid wastes containing specific naturally occurring radionuclides. The states of Illinois and Wisconsin have developed disposal criteria of water treatment plant wastes containing radium. Other states, including New Hampshire, have disposal criteria for wastes containing high levels of NORM radiation from uranium and radium. Most states will most likely deal with this situation on an individual basis. In the absence of specific regulations or guidance, water suppliers would be required to dispose of radioactive residuals in accordance with existing solid waste or, where applicable, hazardous waste requirements. The state of Illinois formalized the regulation of water plants generating radium bearing sludges through a memorandum of understanding (MOU) between the Illinois USEPA and the Illinois Department of Nuclear Safety. The MOU requires that water treatment facilities and landfills receiving the radium bearing sludges be licensed as “radiation installations”. The MOU also specifies disposal criteria depending on the level of radioactivity due to the radium. “In general, sludge containing less than five picocuries/g (dry weight) may be disposed of in a permitted landfill”. Sludge with radioactivity levels between 5 and 50 pCi/g may also be disposed of in a permitted landfill, but under more stringent conditions. If the radioactivity exceeds 50 pCi/g, the method of disposal must be reviewed and determined in advance by the regulatory agency. In that situation, the basic standard is that there must be “reasonable assurance that the exhalation rate of radon to the atmosphere or into a dwelling will not exceed an average rate of five picocuries per square meter per second and reasonable assurance against accidental intrusion into the sludge in the future” (Hunton and Williams 1992). New Hampshire currently imposes disposal limitations on water plant residuals having high levels of radioactivity due to some naturally occurring radioactive materials, such as radium. Table 6.9 summarizes certain states’ criteria. Wisconsin has set the following criteria for landfilling of residuals containing radium:

� Solid waste containing 2 pCi/g (dry) or less of Radium-226 can be landfilled in approved sanitary landfills.

� Solid waste containing greater than 2 pCi/g but less than or equal to 50 pCi/g of Radium-226 can be disposed of in selectively approved sanitary landfills. The waste must be mixed with stabilizing solid waste so that the concentration of Radium-226 averaged over any area of 100 m2 will not exceed background levels by more than 5 pCi/g, averaged over any 15-cm thick soil below the surface.

� Solid waste containing over 50 pCi/g requires specific agency review.


77

� The radium-containing waste should be disposed of in its own trench with separate liner and leachate collection/treatment system.

Illinois also addressed land application of lime sludge containing radium. Illinois requires that the sludge be mixed with the soil so as to not increase the radium by more than 0.1 pCi/g.

Table 6.9 Disposal requirements of certain states

New Hampshire

Material Low level waste facility

Pb-210 Not regulated

Radium >0.444 pCi/g

Uranium 238 >58.4 pCi/g

Illinois

Material Landfill Permitted landfill Case-by-case

Total radiation <5 pCi/g 5 to 50 pCi/g >50 pCi/g

Source: Cornwell 2006 Other states address TENORM in various ways. Although thirteen states currently have regulations addressing TENORM, some only regulate TENORM from specific industries (e.g., oil and gas or phosphate production), while others address all sources of TENORM. For example:

� In Maine, non-exempt facilities abiding by the state’s standards for TENORM radiation protection, worker safety, disposal and transfer of waste, dilution of wastes, and unrestricted use and conditional release, may receive a license to transfer or dispose of TENORM wastes without quantity restrictions (10-144A CMR 220, Subpart N).

� Louisiana issues similar licenses to non-exempt facilities and requires that a manifest be obtained from the department of Environmental Quality prior to shipping TENORM waste to a disposal facility (LAC 33:XV. 1408 and 1418).

� Texas also issues general licenses to non-exempt facilities. Systems transferring waste for disposal must choose a facility licensed to accept TENORM wastes (25 TAC 289.25 (f) and (h)).

Most states do not have specific TENORM regulations and regulate it the same ways as all other sources of radiation.

For more information of state regulations, see http://www.tenorm.com/regs2.htm#States


78

The Department of Transportation (DOT) regulates the shipment of any radioactive waste (USDOT 1976). DOT is a possible regulatory authority if the waste is shipped off-site for disposal. The waste can be considered radioactive by DOT if (1) a state authority has designated the waste as radioactive, or (2) the radioactivity exceeds DOT established levels. DOT defines a radioactive waste as a material that has a specific activity of over 2,000 pCi/g. Also, if a state designates a waste as radioactive then DOT regulations apply. In such cases, shipment must be according to 49 CFR Part 172.392. Which requires that the waste be packaged in leak-proof containers with acceptable levels of external radiation and transported in appropriately marked vehicles.

Ultimate Disposal Options

Table 6.10 summarizes the disposal options and notes possible constraints for these methods due to radionuclides.

Table 6.10

Common disposal considerations for residuals containing radioactivity

Direct discharge

� System must have a NPDES permit � Systems must meet state radionuclides limits

Discharge to a POTW � Systems must meet the requirements of the POTW and meet state permitting requirements

Underground injection � Class I hazardous injection wells may be a disposal option for radioactive or hazardous wastes

� Systems should check with their state to determine whether the state has more stringent UIC requirements

� USEPA has the authority to take action on any residential waste disposal system if the system introduces contaminants into a USDW whose presence or likely presence causes an imminent and substantial endangerment to public health

Landfill disposal � Systems must check with their states to determine whether landfilling is an acceptable means of disposal for hazardous and nonhazardous solid waste containing radionuclides

Source: USEPA 2005a

Figures 6.8 through 6.10 show flow charts that summarize the ultimate disposal options available to drinking water utilities that produce residuals containing radioactivity. Most of the constraints regarding these materials are based on State regulations. Under Federal regulation the presence of radioactivity does not eliminate any disposal option.


79

Source: USEPA 2005a *Check with the state radiation program to see if beta/photon emitters are considered byproduct material and contact the NRC Regional office or relevant agreement state agency to discuss potential licensing HLDR treatment standards also apply. Check with the state Radiation program to determine the proper disposal methods for waste containing radionuclides and hazardous waste

Figure 6.8 Decision Tree 1: Solids residuals disposal containing radioactivity

Use intermediate

processing to separate

out the liquids

Does the waste

contain non-exempt

quantities of uranium

or beta/photon

emitters?*

Disposal in a solid

waste, hazardous

waste, or LLRW

landfill, or any landfill

licensed by the state

to accept TENORM

wasteH

Identify the quality

and quantity of the

residual

Is the waste

hazardous?

• Sludge

• Granular media

• Resin

• AA media, IBS media

• Spent membrane

Does the wastes

contain

radionuclides?

For liquid residuals

disposal, see Liquid

Residuals Decision

Tree 2 (Figure 6.9)

Is the waste a solid

according to the Paint

Filter Liquids Test?

Dispose in a solid

waste landfill

Does the

waste contain

radionuclides?

Dispose in a landfill

licensed to accept

mixed wasteH

Does the waste

contain non-exempt


or beta/photon

emitters?*

Dispose in a

hazardous waste

landfill and meet all

RCRA Subtitle C

requirements

Dispose in a LLRW landfill permitted to accept

hazardous waste or a hazardous waste landfill

licensed to accept TENORM wasteH

Yes

No

Yes

Yes

No

No

NoNo

Yes

Yes

No

Yes

Use intermediate


out the liquids

Use intermediate


out the liquids

Does the waste

contain non-exempt


or beta/photon

emitters?*

Does the waste

contain non-exempt


or beta/photon

emitters?*

Disposal in a solid

waste, hazardous

waste, or LLRW



to accept TENORM

wasteH

Disposal in a solid

waste, hazardous

waste, or LLRW



to accept TENORM

wasteH


and quantity of the

residual


and quantity of the

residual

Is the waste

hazardous?

Is the waste

hazardous?

• Sludge

• Granular media

• Resin


• Spent membrane

• Sludge

• Granular media

• Resin


• Spent membrane

Does the wastes

contain

radionuclides?

Does the wastes

contain

radionuclides?



Residuals Decision

Tree 2 (Figure 6.9)



Residuals Decision

Tree 2 (Figure 6.9)







Dispose in a solid

waste landfill

Dispose in a solid

waste landfill

Does the

waste contain

radionuclides?

Does the

waste contain

radionuclides?


licensed to accept

mixed wasteH


licensed to accept

mixed wasteH

Does the waste

contain non-exempt


or beta/photon

emitters?*

Does the waste

contain non-exempt


or beta/photon

emitters?*

Dispose in a

hazardous waste


RCRA Subtitle C

requirements

Dispose in a

hazardous waste


RCRA Subtitle C

requirements







Yes

No

Yes

Yes

No

No

NoNo

Yes

Yes

No

Yes


80

Source: USEPA 2005a

Figure 6.9 Decision Tree 2: Liquid residuals disposal containing radioactivity

Does the liquid containing Ra or

U meet POTW discharge

requirements (CWA, state limits,

TBLLs)?

Contact the appropriate EPA

Regional or State UIC program

office to see whether Class V

injection is a disposal option


regional or state UIC program

office to see whether Class I

injection (below a USDW) is a

disposal option

Does the liquid meet direct

Discharge requirements

(CWA/NPDES, state, and local

limits)?

Is direct discharge the most

cost-effective or practical (or

only) option?

Secure a permit from the state

Direct Discharge

Would the system’s discharge

cause pass-through or interference

at the POTW?

Do the liquids contain

uranium

that is exempt from NRC

regulations (i.e., less than

0.05 percent by weight)?

Contact NRC or Agreement State

for processing and disposal

requirements

Will the POTW accept the

residual waste?

Is discharge to a POTW the most

cost-effective or practical (or only)

option?

Secure a permit from the state

Discharge or transport to

POTW

Would injection to a Class V

well be the most cost-

effective or practical (or only)

option?

Does the liquid meet the

standards of 40 CFR

144.12 and any state

and local limits?

Is the liquid considered

hazardous according to

40 CFR 261.3?

Is the liquid considered radio-

active according to 10

CFR Part 20, appendix B,

Table II, Column 2?

Would injection to a Class I well

be the most cost-effective or

practical (or only) option?

Is there access to a

receiving body?Is there access to a POTW? Is underground injection

available?

Consider additional processing

and/or waste minimization

methods or other

disposal options

No

Yes

Yes

Yes

Yes

No

No

No

Yes

Yes

Yes

No

Yes

No

Yes

No

No

No

No

Yes

No

No

Yes

Yes

Yes

Yes

No

No

Yes

No




TBLLs)?




TBLLs)?













disposal option





disposal option




limits)?




limits)?



only) option?



only) option?

Secure a permit from the stateSecure a permit from the state

Direct DischargeDirect Discharge



at the POTW?



at the POTW?


uranium





uranium






requirements



requirements


residual waste?


residual waste?



option?



option?

Secure a permit from the stateSecure a permit from the state


POTW


POTW




option?




option?


standards of 40 CFR


and local limits?


standards of 40 CFR


and local limits?



40 CFR 261.3?



40 CFR 261.3?




Table II, Column 2?




Table II, Column 2?








receiving body?


receiving body?Is there access to a POTW?Is there access to a POTW? Is underground injection

available?

Is underground injection

available?



methods or other

disposal options



methods or other

disposal options

No

Yes

Yes

Yes

Yes

No

No

No

Yes

Yes

Yes

No

Yes

No

Yes

No

No

No

No

Yes

No

No

Yes

Yes

Yes

Yes

No

No

Yes

No


81

Source: USEPA 2005a

Figure 6.10 Decision Tree 3: Liquid residuals disposal - intermediate processing

MIXED WASTE

Mixed waste is regulated under RCRA and the Atomic Energy Act (AEA) of 1954. Mixed waste “contains both hazardous waste and source…or byproduct material subject to the Atomic Energy Act of 1954” (42 USC 6903.41). Therefore, systems generating waste containing uranium or thorium (source material) as well as hazardous waste could potentially have a mixed waste. If wastes contain licensable amounts of source material (any concentration exceeding the “unimportant quantity” in 10 CFR 40.13 (a)) and hazardous waste, these wastes must be disposed of at a facility authorized to accept mixed waste. Because there are limited disposal pathways, generation of a mixed waste should be avoided if at all possible. (USEPA 2005).




Will the liquid residual

require intermediate

processing?

Identify the quality and

quantity of the residual

See the Solid

Residuals Decision

Tree

Can the liquid be

reintroduced to the main

treatment train (recycle)?

See Liquids Residual

Decision Tree 2

Solid waste

stream

generated

Liquid waste

stream

generated

• Filter backwash and Filter-to-waste

• Concentrate

• Brine

• AA/IX/IBS Backwash and rinse waters

• Acid neutralization

• Liquids from dewatering

Recycle

Yes

No

Yes

No Yes

No









processing?



processing?





See the Solid

Residuals Decision

Tree

See the Solid

Residuals Decision

Tree

Can the liquid be



Can the liquid be




Decision Tree 2


Decision Tree 2

Solid waste

stream

generated

Solid waste

stream

generated

Liquid waste

stream

generated

Liquid waste

stream

generated


• Concentrate

• Brine





• Concentrate

• Brine




RecycleRecycle

Yes

No

Yes

No Yes

No


83

CHAPTER 7

LANDFILL

Landfills have traditionally been used for the final disposal of solid drinking water treatment residuals. For nonhazardous solids, there are two types of landfills available: municipal solid waste landfills (MSWLFs) and monofills. Solids that are classified as “hazardous” by the definitions of RCRA and described in Chapter 4 must be disposed of in Hazardous Waste Landfills. Solids that contain radioactivity may have to be disposed of in Low Level Radioactive Waste Facilities (LLRWF). Each of these landfills is described in this chapter. The disposal of solid wastes is regulated under RCRA. Under this law, the producer of the material (in this case, the drinking water utility) must determine whether this material is hazardous using the procedure described in Chapter 4. In some states water treatment residuals must be disposed of in industrial waste landfills that, although similar to MSWLFs, can have different requirements.

NONHAZARDOUS LANDFILLS

Nonhazardous landfills are regulated according to RCRA Subtitle D. This section of RCRA is meant to ensure the protection of human health and the environment through good management of the landfill. These regulations cover landfill location, operation and design, groundwater monitoring, closure procedures and financial assurance.

Municipal Solid Waste Landfills For those utilities dewatering their solid/liquid waste streams, landfilling of the resultant solids is a common method for final disposal. Landfilling is also an option for the disposal of spent media if the material does not fail any part of the TCLP. These landfills can generally accept wastes containing TENORM. In the case where the sludge is disposed of in a municipal landfill, the utility often has little to do except determine the requirements for using the landfill. In some cases the landfill must be approved to accept industrial wastes in order to dispose of water plant residuals at the site. The principal constraint on using the landfill is usually the allowable solids concentration. While some landfill owners or state regulations will set a specific solids concentration, usually the requirements are more qualitative. The requirements may be stated as “no free water” or “must behave as a solid” or “must be handleable by earth moving equipment.” In most cases, the material must pass the Paint Filter Liquids Test USEPA Method 9095 (USEPA 1998a). MSWLFs are generally owned by a government entity or in some cases by a private concern. They accept a mixture of residential and industrial waste. The cost associated with disposal at a MSWLF are those involved with transporting the material to the landfill, and the fee

A list of all nonhazardous MSWLF can be found at: www.epa.gov/epaoswer/non-

hw/muncpl/landfill/section3.pdf


84

imposed by the landfill operator, often referred to as a tipping fee. A typical MSWLF is shown in Figure 7.1.

Source: www.epa.gov

Figure 7.1 Typical municipal solid waste landfill

What Type of Data is Needed to Dispose of Residuals in a MSWL?

Landfill operators may request data on the specific characteristics of the residuals to be

disposed. Federal requirements dictate that a residual material must pass, at a minimum, a solids test (typically the Paint Filter Liquids Test) and the ignitability, corrosivity, reactivity and toxicity characterization tests of RCRA. As described in Chapter 4, the hazardous criteria applicable to drinking water treatment residuals are the pH and the TCLP results of the material. A material failing the TCLP would be prohibited from disposal at a MSWL. If the material was characterized as hazardous because of its pH (corrosivity) then the pH would have to be adjusted before the material could be accepted.

Monofill

A monofill is a landfill that has been designed to handle one material; in this case, a monofill would be designed to accept only drinking water treatment residuals. In most cases, the monofill is owned and operated by the utility that generates the residual. Utilities have chosen to build these facilities because of increasing tipping costs, distance (and so expense) of transportation and reduced availability of space in existing landfills. Utilities limit their exposure to liability as well, since they control what type of material is put into these landfills. The two major types of sludge monofilling methods are trench filling and area filling. Trench filling can be further subdivided into narrow trench and wide trench monofilling techniques. The three basic types of area filling include the area fill mound, area fill layer, and diked containment methods. Method selection is determined principally by sludge solids content, sludge stability, site hydrogeology (location of groundwater and bedrock), ground slope, and land availability.

For more information on constructing a

monofill, see Cornwell (2006)


85

What Information Would be Required to Build a Monofill for Disposal of Residuals?

Design requirements for sludge monofills vary from state to state; however, in the majority of instances the general design criteria for sludge monofills mirror those that are imposed on municipal solid waste landfill design. It is likely that strong similarities would also be found in the permitting processes, particularly with regard to the required components of an application package. In addition to site acceptability and detailed design, permit application approval for most landfills involves submittal to reviewing authorities the following standard information:

� Soils and hydrogeological analyses � Operational plan � Erosion and sedimentation and control plan � Groundwater monitoring plan

Because most of the concern regarding land disposal of WTP sludge stems from concern of groundwater contamination, more detailed information regarding the characteristics of the waste to be landfilled, such as background metals concentrations (determined by a total metals analysis) and results of leaching tests, may be required as part of the permit application (see Cornwell et al. 1992).

HAZARDOUS WASTE LANDFILL

Hazardous waste landfills under RCRA Subtitle C, accept wastes that are characterized as hazardous by the definitions listed in RCRA (see Chapter 4). For drinking water treatment residuals that would include materials that have failed the TCLP for one or more contaminants, or have exhibited corrosive characteristics (pH). Some landfills, depending on their state license, can also accept certain materials that contain TENORM. Hazardous waste landfills are designed, built and operated according to much stricter requirements than nonhazardous landfills. These standards were set by RCRA and are discussed in Chapter 4. The standards govern the location, design, construction, operation and final closure of the landfill.

Hazardous waste landfills must have a complex liner and leachate collection system. The impact to the groundwater is monitored through leak detection mechanisms and groundwater monitoring wells. A schematic of a hazardous landfill is shown in Figure 7.2.


86

Figure 7.2 Schematic of hazardous waste landfill after closure

What Data Would be Required to Dispose of Material in a Hazardous Waste Facility?

The generator of the waste, in this case the drinking water treatment utility, is responsible to determine if the material is hazardous. So, the RCRA hazardous characterization data would be required, as a minimum. As with nonhazardous landfills, the material must be categorized as a solid, and so data from the required test (usually the Paint Filter Liquids Test) would be required. In addition, hazardous waste must be containerized in order to be transported, as described in The Hazardous Materials Transportation Act, described in Chapter 4. These materials must also be manifested and tracked. Further, since mixed waste (hazardous plus radioactive) is specifically prohibited from a Hazardous Waste Facility, the quantity of radioactivity will have to be determined.

LOW LEVEL RADIOACTIVE WASTE LANDFILL (LLRW)

Low level radioactive waste landfills are licensed by the Nuclear Regulatory Commission

(NRC) or by a state agency through an agreement with the NRC. These LLRW landfills must conform to more strict construction, operation and closure requirements than non-hazardous landfills.

There is no federal requirement to test water residuals specifically for radionuclides and no specific federal regulations governing landfill disposal of water treatment plant waste containing TENORM (and possibly source material). However, USEPA established methods that

Native Soils

Gravel

Clay

Hazardous Waste

Leachate

Topsoil

Vegetation

Leachate

Primary

Collection

SystemLeachate

Detection

System

Final Clay

Cover

Sand

HDPE Cover Liner

Intermediate Cover

HDPE Primary

Liner

HDPE Secondary

Liner

Native Soils

Gravel

Clay

Hazardous Waste

Leachate

Topsoil

Vegetation

Leachate

Primary

Collection

SystemLeachate

Detection

System

Final Clay

Cover

Sand

HDPE Cover Liner

Intermediate Cover

HDPE Primary

Liner

HDPE Secondary

Liner


87

can be used to characterize wastes for TENORM. This information can be found at: www.epa.gov/radiation/mixed-waste/about.html.

Table 7.1

Operating low level radioactive waste landfills

Barnwell – South Carolina

Will, after June 30, 2008, accept LLRW only from organizations in South Carolina, Connecticut, and New Jersey. For more information, including waste transport, disposal rates, and site availability, see http://www.state. sc.us/energy/RadWaste/rwdp_index.htm.

Richland – Washington

Accepts certain types of TENORM (although not hazardous or mixed) wastes from all states. Accepts licensed source material only from the 11 states in the Northwest and Rocky Mountain Compacts. State regulators anticipate including activity limits for uranium-238 and radium-226 in the facility’s renewed license. For more information, including waste transport, disposal rates, and site availability, see http://www.ecy.wa.gov/programs/ nwp/llrw/llrw.htm.

Envirocare – Utah

Has dedicated TENORM disposal and is the only LLRW landfill authorized to accept certain kinds of mixed waste. Does not accept LLRW from Northwest Interstate or Rocky Mountain Compact states. For more information, see http://www.envirocareutah.com.

Source: USEPA 2005a

Currently, there are only three operating LLRW landfills in operation in the United States. Table 7.1 lists these facilities and describes the type and origins of waste that can be disposed of at each facility. It should be noted that these landfills can accept waste from only certain states. The table contains the internet address for each location, and so the specific requirements and disposal costs can be obtained directly from the landfill operators.

What Data Will be Needed for Disposal at a LLRW Landfill?

Each of these landfills has specific requirements, based on their state permits. At a

minimum radionuclide data, generated from the methods discussed above will be required, as well as data from TCLP testing.


89

CHAPTER 8 LAND APPLICATION AND BENEFICIAL USES

BACKGROUND

Land application of drinking water treatment residuals is becoming increasingly popular

because of the high cost of other disposal methods. Specific options available for the land application of drinking water treatment residuals include agricultural use, silvicultural (forest) application, and application for reclamation of disturbed and reclaimed land (ASCE et al. 1996).

The obvious benefit of this option to the water utility is that it has the potential to provide a waste disposal mechanism for large quantities of liquid residuals, as well as solids in some cases. The benefit to the end user could be the reuse of water (especially attractive in water poor areas) and in some situations, amendment of the soil. Possible disadvantages include phosphorous binding of the soil if fresh coagulant sludges are land applied.

Agricultural land application of water treatment residuals is the most commonly practiced beneficial use method. A detailed description of the process involved for land application of water residuals is outlined in “Land Application of Water Treatment Plant Sludges” (Elliott et al. 1990). This AwwaRF land application manual provides a very good source of technical information concerning the principals and design associated with land applying residuals. Implementation logistics and residuals quality requirements are also summarized in the report. Using lime residuals on agricultural lands has been done for many years. The benefit of applying these residuals to land is as a replacement for the limestone typically used to adjust soil pH. Using coagulant residuals has resulted in neutral or slightly positive impacts on crop growth. Some of the benefits associated with the addition of coagulant residuals to agronomic soils include:

� Improvement to soil structure � Soil pH adjustment � Addition of trace minerals � Increased moisture holding capacity � Soil aeration Some negative effects on soil characteristics have also been documented. Some

coagulant residuals have a tendency to bind plant available phosphorus in soils (Elliott and Dempsey 1991, Knocke et al. 1991). Also, aluminum phytotoxicity could also be a problem if the soil pH is not maintained at or above 6.5 (Elliott and Dempsey 1991). Once land application is identified as a desirable option, the utility will need to find end users and determine the specific requirements of the user. A permit issued by the state will also

A detailed description of the process involved for land application of water residuals is outlined in “Land Application of Water Treatment Plant Sludges” (Elliott et al. 1990).


90

be required. Other aspects that the utility will have to determine in order to decide if this is truly a viable option include:

� Distance to end user (this greatly impacts total costs, since transport is so expensive)

� Residuals application design � Agricultural methods � Storage of residuals � Application rates � Monitoring and reporting In many cases, small systems may find that using liquid residuals for irrigation could be a

beneficial reuse alternative.

Land application of residuals can be performed using either liquid or cake solids residuals. The liquid or solid material could be effectively land applied at any solids concentration found to be economically feasible by a utility and acceptable to the land owner. The amount of dewatering required is based primarily on hauling distances to the application site, storage facilities required, residuals water value, and land owner preference. Solids concentrations for liquid residuals applications from coagulation processes range from 0.5 to 10 percent, while cake residuals applications require a solids concentration of greater than 15 percent. Lime sludges can be applied as a liquid up to 10 percent solids concentration and as a solid if the solids concentration is over 40 percent. Liquid residuals applications, where feasible, can provide a number of advantages. Liquid applications only require gravity sedimentation and thickening of the residuals, thereby eliminating the need for dewatering facilities and equipment. Liquid applications to agronomic soils can be applied to soils throughout the growing season depending on the type of crop produced and the application technique used. Applications throughout the growing season may provide an additional water value for crop growth. A disadvantage of land applying liquid residuals is the large volume of residuals, which directly impacts the handling and transportation costs.

Liquid applications are only economically attractive when application sites are within close proximity to the water treatment plant, or if relatively small quantities of residuals are generated.


91

Land application of dewatered residuals requires dewatering to a solids concentration that can be handled by front-end loaders, transported by dump trucks, and spread onto farmland using manure type spreading equipment. The volume reduction, however, significantly reduces transportation and handling costs. Cake solids are not typically applied during the growing seasons due to the potential for physical crop damage during spreading, during heavy rains, or freezing conditions. Therefore, a residuals storage facility may be required to stockpile residuals until land application is possible. Uneven distribution and soil clumping are also potential problems using cake solids application. In order to increase the value of coagulant residuals for agricultural use, a number of contractors and utilities have developed processes that combine residuals with other beneficial agricultural products. Residuals amendments include lime addition, fertilizers, biosolids, and finished compost materials. Any of these products could effectively increase the agronomic value of the water treatment residuals. Fertilizers (nitrogen, phosphorous, and potassium), compost, or biosolids could be blended with residuals prior to or during the land application process. Blending the residuals with any of these amendment at the proper ratios increases the residuals value and, as a result, makes marketing of residuals to farmers an easier task.

What Type of Data are Needed to Use Land Application?

The drinking water utility will need to obtain a permit from their state in order to dispose

of their residuals through land application. States vary in how they handle this procedure; some states have developed a standardized application (e.g., New Jersey) while others treat the requests on a case-by-case basis.

Federal regulations (RCRA) forbid the application of a hazardous material to the land where it may impact either surface or groundwater source. So, the residuals will have to pass the RCRA hazardous tests as demonstrated through the TCLP. The chemical and physical parameters that should be analyzed for residuals characterization prior to land applying residuals are presented in Table 8.1. Regulatory agencies responsible for granting land application permits may require a utility to test for some or all of these parameters as part of the permit application process. Subsequent testing may be required on an annual or semiannual basis for permit compliance. Many of the states regulate residuals beneficial use on a case-by-case basis depending on the type of use and quality of the residuals. Therefore, no exact list of parameters will apply to every utility.

These chemical data will be important in determining the rate at which the residuals can be applied. Most residuals do not contain excessive concentrations of heavy metals. For this reason, metals will probably not control the annual application rate of sludge. The federal government has mandated that Cd loadings be less than 0.5 kg Cd/ha-yr (0.45 lbs Cd/ac-yr). Additionally, many states limit the annual loading of Cu, Cr, Pb, Hg, Ni, and Zn. Using the rates determined for fertility or soil pH adjustment, the annual loading rate of each metal should be calculated to see if any of these limits are exceeded. If so, the sludge application rate will be dictated by the metal which results in the lowest application of sludge per acre.

While not usually affecting annual application rate, metal buildup in the soil will determine how many years a site can be used for sludge disposal, since USEPA guidelines and the regulations in many states stipulate a lifetime loading limit for each metal.


92

Table 8.1

Important residuals quality parameters for land applying coagulant residuals

Parameters Units

Physical tests

Solids concentration percent

Color - -

Texture - -

Soil aggregation - -

Moisture content percent

Grain size analysis (clay/silt/sand) percent

Specific weights lb/ft3 (kg/m3)

Chemical tests

Nutrients

Total Kjeldahl nitrogen lb/ton (mg/kg)

Total phosphorus lb/ton (mg/kg)

Potassium lb/ton (mg/kg)

Ammonia-nitrogen lb/ton (mg/kg)

Nitrate/nitrite - N lb/ton (mg/kg)

Calcium lb/ton (mg/kg)

Calcium carbonate equivalent (CCE) percent

Metals

Total metals lb/ton (mg/kg)

TCLP metals mg/L

Radionuclides

Gross alpha pCi/g

Gross beta pCi/g

Radium-226 pCi/g

Organics

Total organic carbon (TOC) lb/ton (mg/kg)

Toxicity

Phytotoxicity-Microtox test

Other tests

Total coliform no/gram

pH - -

Source: Adapted from Cornwell et al. 2002


93

Table 8.2

Recommended cumulative metal limits for cropland

Soil cation exchange capacity (meq/100 g)

<5 5 to 15 >15

Metal ---------------kg/ha (lb/ac)------------------

Pb 560 (500) 1,120 (1,000) 2,240 (2,000)

Zn 280 (250) 560 (500) 1,120 (1,000)

Cu 140 (125) 280 (250) 560 (500)

Ni 140 (125) 280 (250) 560 (500)

Cd 5 (4.4) 10 (8.9) 20 (17.8)

Source: USEPA 1983a

Application of sludge should stop before the allowable lifetime loading of metals has been reached. The values given in Table 8.2 are recommendations from the USEPA. Under the solid waste regulations of the Clean Water Act, they apply to any waste that is land applied. Most states have adopted these or more restrictive metal limits. These values are for the total metals applied. Determine total metals added at the initial application rate and divide the allowable loading by this number. This will give the estimated site life in years. Because residuals do not contain high concentrations of heavy metals, sites can be used for many years based on metal-loading criteria.

BENEFICIAL USES

Every utility would like to find a market for their treatment residuals. Some utilities have been successful selling or giving away their residuals to end users. However, this requires a marketing strategy. Commercial Application and Marketing of Water Plant Residuals (Cornwell et al. 2000) provides such guidance and should be consulted for more information. Basically, the required elements of the marketing strategy would include: • A review of local and state regulations and history of beneficial use in that state • Residuals characterization • A list of potential beneficial use options • The requirements for performing beneficial use for the end user • Assessment of existing and future required facilities • Economic and noneconomic analysis • Regulatory permitting • Development of marketing package • Marketing residuals to potential end users • Contractual agreements • Project development and implementation • Compliance sampling and monitoring (if required)


94

Regulatory Evaluation The first task that should be performed by a utility when initiating a beneficial use program is to determine if any state or local regulatory guidelines exist for beneficial use of water treatment residuals. Many states have previous experience dealing with residuals regulation and some states have guidelines that could provide a framework of how to develop a beneficial use program. Some of the federal guidelines were discussed in Chapter 4: however, state guidance will be the most important in determining allowable uses, application procedures, etc. It is best to involve the regulatory agency that will oversee the permitting process at the beginning of the project to determine which tasks must be accomplished for establishing a successful program. If regulatory guidelines for beneficial use exist, then an effort should be made to locate utilities that have received beneficial permits in the past and review that utility’s experiences. Nearby utilities that have experience with one or more forms of residuals beneficial use could provide invaluable information on how to develop a successful program or why a certain program did not succeed.

Residuals Characterization The next task necessary for marketing residuals for beneficial use applications is to sample residuals and perform a complete chemical and physical analysis of the contents. The chemical and physical properties of the residuals will ultimately dictate how a particular residual could be beneficially used in a safe manner. Accurate analysis of the residuals is critical, and a utility should be aware that residuals quantities could change seasonally. A listing of recommended physical and chemical parameters that should be analyzed is shown in Table 8.3. Table 8.4 lists the requirements of example beneficial uses. Analysis of these parameters should provide enough information to initiate the marketing of residuals to end users. Also, compliance with regulatory guidelines can be assessed at this point. Due to seasonal changes in raw water quality and changes in treatment chemicals applied during different times of the year, quarterly sampling of residuals may be necessary to fully characterize the variations in the residuals quality. Even more samples would be required for any type of statistically valid analyses.


95

Table 8.3

Physical test parameters useful for beneficial use

Use Solids co

nce

ntrat

ion (%

)

Colo

r

Tex

ture

Soil a

ggre

gat

ion

Moistu

re c

onte

nt (%

)

Gra

in siz

e an

alysis

(cla

y/silt/sa

nd) %

)

Liq

uid

lim

it (%

solids)

Pla

stic

lim

it (%

solids)

Mas

s den

sity

(lb

/ft3

[kg/m

3])

Spec

ific

gra

vity

Shrinkag

e (%

)

Spec

ific

wei

ght (lb/ft3

[kg/m

3]

Shea

r stre

ngth

(lb

/ft2

[kg/m

2])

Moistu

re ret

ention (cm

wat

er/c

m soil d

epth

)

Land application x x x x x x x

Cement manufacturing x x x x x x

Brick making x x x x x x x x

Turf farming x x x x x x x x x

Composting x x x x x x x x x

Soil production x x x x x x x x x x

Road subgrade x x x x x x x x

Forest land application x x x x x x x

Citrus grove application x x x x x x x

Nutrient control x x x x

Landfill cover x x x x

Land reclamation x x x x x x x x x x x x x

Hydrogen sulphide (H2S) binding

x



96

Table 8.4

Chemical test parameters useful for residuals beneficial use

Nutrients Metals Radionuclides Organics Toxi-city Other tests

Use TK

N (lb

/ton) [m

g/k

g])

Tota

l Phosp

horu

s (lb/ton [m

g/k

g])

Pota

ssiu

m (lb

/ton [m

g/k

g])

Am

monia

-nitro

gen

(lb

/ton [m

g/k

g])

Nitra

te/N

itrite

-N (lb

/ton [m

g/k

g])

Cal

cium

(lb

/ton [m

g/k

g])

CCE (%

)

Tota

l m

etal

s (lb/ton [m

g/k

g])*

TCLP R

CR

A m

etal

s (m

g/L

)H

Met

al o

xid

es (lb

/ton [m

g/k

g])I

Gro

ss a

lpha

(pCi/g)

Gro

ss b

eta

(pCi/g)

Rad

ium

-226 (pCi/g)

TO

C (lb

/ton m

g/k

g)

TCLP v

ola

tile

s/Sem

ivola

tile

s (m

g/L

)H

Loss

of ig

nitio

n (%

)

Phyto

toxic

ity-M

icro

toxte

st

Tota

l co

lifo

rm (no./g)

pH

Land application x x x x x x x x x x x x x x x x

Cement manufacturing

x x x x x x x x x x

Brick making x x x x x x x x x

Turf farming x x x x x x x x x x x x x x x x x

Composting x x x x x x x x x x x x x x x x x

Soil production x x x x x x x x x x x x x x x x

Road subgrade x x

Forest land x x x x x x x x x x x x x x x x

Citrus grove x x x x x x x x x x x x x x x x x

Nutrient control x x x x x x x x x x x x x x x x

Landfill cover x x x

Land reclamation x x x x x x x x x x x x x x x x x

Source: Cornwell 2006 *Total metals analyses include A1, As, Ba, Cd, Cr, Cu, Fe, Pb, Mg, Mn, Hg, Ni, Se, Ag, Zn, and Mo HTCLP analyses is as specified by 40 CFR Part 261 [USEPA 1983b]. The RCRA metals include Ag, Ba, Cd, Cr, Pb,

As, Se, and Hg IThese include major oxides of the following elements: Al, Si, Fe, Ca, Mg, S, Na, K, and Mn

After establishing a short list, a general search can be used to identify which particular end users exist. The goal should be to establish as many agreements as possible with potential end users in order to have a variety of outlets for beneficial use in case some are unsuccessful.


97

User Requirements Prior to marketing residuals for a particular application, a utility must first determine the needs of the potential end user, storage requirements, and residuals characteristic requirements. Facility requirements must also be considered and could significantly impact project costs. Some key issues to be addressed include: • What is the optimal or desired solids concentration and is further dewatering such

as air drying required? • What are the residuals chemical and physical properties that are most important? • Are any additions such as lime, fertilizers, or other additives required? • What quantity of residuals could the end user accept? • Are residuals storage facilities and additional equipment required by the utility or

the end user? A complete evaluation of each of these questions should be performed to determine if each alternative is feasible.

Preliminary Economic Analysis The economics associated with a beneficial use program would be an important parameter for determining project feasibility. A utility must evaluate the costs associated with performing each potential beneficial use alternative to determine if the beneficial use alternative is economical. The probable capital and viable operating and maintenance (O&M) costs for each potential alternative should be evaluated at this point. This would serve as a reality check to determine if further pursuit of beneficial use alternative is economically warranted. The alternatives should be compared to a base case disposal option such as landfilling or the existing residuals disposal method the utility is using. The key cost elements that need to be considered are presented below.

Capital Costs

• Residuals equalization basins • Residuals thickeners • Residuals dewatering equipment • Residuals air drying facilities • Residuals storage facilities • Residuals blending equipment • Equipment for residuals handling/transportation

Operating Costs

• Dewatering • Residuals handling/loading • Transportation • User fees • Compliance sampling and analysis


98

Noneconomic Analysis A noneconomic analysis should also be conducted to evaluate non-monetary considerations for each beneficial use plan. These would include such things as reliability, complexity of requirements, increased traffic, and public perception, as examples. The results from the noneconomic analysis should be linked with the beneficial use economics in order to determine whether the beneficial use option should be pursued.

CONTRACT HAULERS

Finding a user for drinking water treatment residuals has been successfully done by a number of utilities and could possibly be accomplished by a small system. This option, however, requires a thorough investigation of the options available locally. Such a marketing analysis may be too complex and time consuming for a small utility, but the benefits, if successful could be tremendous.

An alternative to developing a beneficial use program in-house is to use a private contractor to haul and dispose of the residuals. These contractors will haul either liquid (thickened residuals) or dewatered residuals. For a small system, developing a contract to haul thickened residuals rather than dewatered residuals may prove more economical. Contractors can haul liquids from a thickener with a truck fill line or they can pump/dredge residuals from a lagoon. If the residuals are not too thick in the lagoon they can use a vactor type truck.

If the residuals are dewatered either mechanically or nonmecanically then they can be hauled with front end loaders and dumpster containers or dump trucks.

Utilities can often receive competing bids for these services. But, it is critical to specify that the contractor have all permits for proper disposal and review them. The utility can still be held liable if the residuals are improperly disposed of.


99

CHAPTER 9

SEWER AND DIRECT DISCHARGE

DISCHARGE BY CONNECTION TO A POTW

For the disposal of a liquid residual, most water plant personnel would prefer to connect to a sewer line, for disposal to a Publicly Owned Treatment Works (POTW). Compared to other options, it is usually the most economical as it eliminates the need for transporting the material. But there are restrictions to consider.

Discharges to the sanitary sewer are subject to USEPA’s National Pretreatment Standards (EPA 40 CFR 403: General Pretreatment Regulations for Existing and New Sources of Pollution) and any additional pretreatment requirements set by the state or local wastewater treatment facility. The requirements imposed by a wastewater treatment facility through a permit and local ordinance or both are necessary to enable the facility to achieve compliance with their NPDES permit. Pretreatment standards are typically site specific. These standards ensure that the waste will not impact the POTW’s treatment processes, won’t impact its NPDES permit, or its biosolids management.

What Kind of Data Will a POTW Require?

The POTW will require some information about the chemical nature of the material that will be discharged, as well as quantity and timing of flow. Every individual POTW will have different requirements, but the list in Table 9.1 is an example of what may be required. As a minimum, any material released to the POTW must be nonhazardous, so a TCLP will be required showing that none of those parameters are exceeded.

Table 9.1

Parameters of importance to a POTW

Biological oxygen demand (mg/L) Aluminum

Total suspended solids Arsenic

Total phosphorous (mg/L) Cadmium

Nitrate (mg/L) Chromium

Chemical oxygen demand Copper

Fats, oil and grease (mg/L) Iron

Fecal coliform (number/100 ml) Lead

pH Mercury

Total nitrogen (mg/L) Molybdenum

Total coliform (number/100 ml) Nickel

Selenium

Zinc

Alpha activity (pico-curies/g)


100

Equalization

Sludge from the sedimentation basin can be withdrawn on a fairly continuous and uniform basis if the basins are equipped with automatic sludge removal mechanisms. In that case, it may be possible to discharge directly to a sewer system. Often, however, basins are cleaned on a discontinuous basis and equalization is required prior to discharge. Spent filter backwash water is produced at very high flow rates for short periods of time and equalization is often required prior to sewer discharge. Regeneration wastes from ion exchange processes are produced only during the time of media regeneration and equalization may be needed, although the volumes are generally small. In many cases, a storage tank or equalization basin will be required to hold the residuals before disposal to the sewer.

Consideration should also be given to time of discharge. The POTW may require discharge during periods of the day when sufficient flow is in the sewer to maintain desired velocities. On the other hand at certain times the sewer may flow full and a sludge discharge is undesirable. Generally, a velocity of about 2.5 fps should be maintained to prevent sedimentation of hydroxide sludge solids. Lime sludge may have settling velocities much higher than coagulant sludges, and it can be difficult to prevent its deposition in sewer lines. For the discharge of compounds toxic to the biological process, it may be necessary to equalize flows to allow for a continuous discharge or proper dilution.

Possible effects, either beneficial or detrimental, of water plant wastes on the biological wastewater process include toxicity to the biological processes, suspended solids removal or increases, BOD/COD removal or increases, hydrogen sulfide removal, and phosphorus removal. Dissolved solids present in the waste could be available in a form and present in a sufficient concentration to hinder the biological process. Defining the toxic effects of inorganic compounds on the biological wastewater treatment process is not a simple procedure. An initial shock load of a toxic compound can have an inhibitory effect on the biological process. However, with many compounds the microorganisms will adapt and adjust to the presence of the inorganic ion. Therefore, even if a pretreatment standard is being met, it is a good rule of thumb to equalize the discharge according to sewer flow patterns in order to provide a fairly uniform concentration of waste to the biological process.

Depending on what type of process the POTW utilizes, additional information on the quality of the residuals may be requested. In addition to the metals listed in Table 9.1, anaerobic processes can be affected by Na+, K+, Ca2+, Mg2+and NH4

+ (Cornwell 2006). Disposal to a sewer facility usually requires easy access to a sewer line, but for small

systems, it may be possible to store residuals on site, and then haul them periodically to the POTW. In this case, the onsite storage, whether it be a tank or some type of lagoon would need to be permitted by the state regulator. The chemical and physical characteristics of the material would still need to be documented, and the POTW may require additional information.

DIRECT DISCHARGE TO SURFACE WATER

The disposal of liquid residuals directly to a receiving water requires an NPDES permit. Discharge decisions are made either by the Regional USEPA offices or by the individual states delegated to write their own permits. It is up to the permit writer to rule on the best available treatment technology for each plant on a case-by-case basis. According to USEPA, the primary


101

criteria for allowance of direct discharge is to meet established in-stream water quality standards at the edge of the mixing zone.

In-stream water quality criteria and standards are developed by individual states (with the use of some federal guidelines). Most states have classified each body of water for a designated use and set in-stream quality guidelines appropriately. Table 9.2 shows example in-stream water quality criteria and standards for several selected compounds. Since standards vary from state to state only examples can be illustrated. The specific agency involved should be contacted. In addition to meeting in-stream water quality standards, some states have established maximum allowable concentrations in the discharge. These limits generally apply if they are more stringent than the allowable discharge that will meet the in-stream water quality criteria. For example, Illinois does not allow a discharge of greater than 15 mg/L fluoride (F). Barium discharge is required to be less than 2 mg/L, even if the 1 mg/L in-stream standard could be met through dilution. Wisconsin has set maximum discharge levels of radium (soluble) in liquid wastes as follows:

pCi/L130

Ra

30

Ra 228226

≤+ (9.1)

These regulations apply to discharge from a water plant, to a storm sewer, or to a surface

body of water. Several states have set limits on suspended solid levels and chlorine residual in the discharge. Arsenic limits have been set at 0.05 m/L for many states.


102

Table 9.2

Example in-stream water quality guidelines and standards

Guidelines

Aquatic life chronic criteria Example standards

Fresh (µg/L)

Salt (µg/L)

Human health* (µg/L)

Stream used for potable water

(mg/L)

Arsenic (dissolved) 72 63 2.2 ng/L 0.05

Barium 1.0

Beryllium 130 3.7 ng/L

Cadmium e 1.16(In(hardness))3.841−

12 10.0 0.01

Chloride 250

Chromium (hexavalent, dissolved)

7.2

54

(trivalent, active, total) e 0.819(In(hardness)).537+

170

(Total) 0.05

Copper 2.0 4(2y) 23(A)

1.0

Cyanide, free 4.2 0.57 20.0

Fluoride 1.4

Hydrogen sulfide 2.0 2.0

Iron, total 1,000

soluble 0.3

Lead e 1.34(In(hardness))5.245−

8.6 50 0.05

Manganese, total 100

soluble 0.05

Mercury 0.00057 0.1 146 ng/L 0.002

Nickel (total) e 0.76(In(hardness)) 1.06+

7.1 13.4

Nitrate (as N) 10

Phenol 1.0 1.0 3,500 0.001

Selenium 35 54 10 0.01

Silver .01e1.72(In(hardness))6.52−

0.023 50 0.05

Sulfate 250

TDS 500

Zinc 47 58 5,000 5.0

Aldrin 0.03 0.003 0.074 ng/L

(continued)


103


Guidelines

Aquatic life chronic criteria

Example standards

Fresh (µg/L)

Salt (µg/L)

Human health* (µg/L)

Stream used for potable water

(mg/L)

Chloride 0.0043 0.004 0.46 ng/L

Endrin 0.0023 0.0023 1.0 0.0002

Heptachlor 0.0038 0.0036 0.28 ng/L

Lindane 0.08 0.0016 0.004

Methoxychlor 0.03 0.03 0.10

Toxaphene 0.013 0.0007 0.71 ng/L 0.005

DDT 0.001 0.001 0.024 ng/L 0.1

Chloroform 1,240 0.19

Radioactivity (Ra226+228) 5 pCi/L

Gross alpha particle activity (excluding radon/uranium)

15 pCi/L

Source: Cornwell 2006 *Values given are the ambient water quality criterion for protection of human health for non-carcinogens, and for carcinogens the value is the risk of one additional case of cancer in 1,000,000 persons. Note: Guideline values are from USEPA, 1980. Standards are selected from various state regulations and do not reflect any one state’s regulations.

New requests for NPDES permits for water treatment residuals disposal will require

information on the chemical, physical characteristics of the material, as well as an estimate of the quantity. It should be noted that the permitting process is typically a lengthy one, sometimes three years or longer.


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CHAPTER 10

UNDERGROUND INJECTION CONTROL WELLS

BACKGROUND

Disposal of drinking water residuals through injection wells has not been a widespread practice. It is expensive and can only be done where the location and geology would allow it. However, as utilities are beginning to use more brackish water and treatments that produce large volumes of waste, this option is being more closely evaluated. A 2006 survey determined that there are currently 101 permitted UIC wells being used for disposal of drinking water treatment residuals. The majority of these are located in Florida (75 wells) and the Commonwealth of Northern Mariana Islands (16 wells.) The remaining are located in Texas, Kansas, Utah and Hawaii. Most of these wells are for the disposal of RO reject water (USEPA 2006).

In 2006, the USEPA’s Underground Injection Control (UIC) Program’s National

Technical Workgroup (NTW) released its recommendations regarding the viability of using UIC wells for drinking water treatment residual disposal. The technical recommendations this group established for the use of UIC wells were based on NTW’s belief that:

With elevated concentrations of various contaminants and the large volumes

involved, the technical workgroup believes that the injection of concentrates

could potentially threaten (drinking water sources) and public health. In

addition, high TDS and differing geochemistry between the native

formation/formation water and the injected concentrates could lead to

precipitation of minerals such as calcite, gypsum, and silica that physically and

chemically affect the permeability and porosity of the receiving formation.

(USEPA 2006).

As discussed in Chapter 4, the Safe Drinking Water Act defines the UIC program. The UIC regulations are designed to ensure that the wells are constructed, operated and maintained in a manner that protects water sources and public health. Under that law, injection wells are classified according to the type of liquid injected. There are five classes of injection wells allowed under UIC regulations, but none specifically address drinking water residuals. The National Workgroup determined that drinking water treatment residuals could possibly be disposed of through Class I hazardous and nonhazardous waste injection wells, Class II enhanced oil recovery (EOR) injection wells and Class V injection wells.

Class I wells inject industrial fluids or municipal wastewater beneath the lowermost underground source of drinking water (USDW). Class I injection wells are designated as

The entire text of the USEPA UIC National Technical Workgroup Recommendations can be

found at: http://www.epa.gov/region5/water/uic/ntwg/dwtr_

final_report_01-19-07.pdf


106

hazardous or nonhazardous, depending on the type of fluids injected. The fluids injected into Class I injection wells are typically associated with industries such as the chemical production, petroleum refining, and metal products industries.

Another option for drinking water treatment residual disposal is injection in oil fields to enhance oil recovery where formation pressures have been greatly lowered due to past oil production. USEPA classifies such wells as Class II EOR wells (sometimes called Class II-R wells). The recovered fluid is treated to remove most of the hydrocarbons from the mineralized water in a device called a separator. Class II EOR wells then inject the mineralized water back into the formation from where it was produced, usually below the lowermost underground source of drinking water.

The use of Class V injection wells may also be an option for residuals disposal. Many Class V injection wells are shallow wells that inject into or above USDWs, while others, such as spent brine return flow wells, are deep wells that inject below the lowermost USDW. Meeting the non-endangerment standard may be difficult for residuals injection wells that inject into or above a USDW. In addition, Class V injection wells are not an option for hazardous waste disposal (USEPA 2006c).

Of the UIC wells that were being used for the disposal of drinking water treatment residuals in 2006, the majority (63 wells) were Class I. The remaining 38 wells are deep Class V wells.

WHAT ARE THE REQUIREMENTS FOR UIC WELL DISPOSAL?

The wells that have been used for drinking water treatment residual disposal were

authorized by the states where the wells are located, under their primacy authority. Of the permits reviewed by the USEPA NTW, it was found that most of the permits/authorizations contained specific casing, cementing (continuous in some state or as needed in other states to protect USDWs), and tubing requirements. All of the permits specified a maximum daily injection volume (up to 2.4 mgd per well) and injection pressure. All operators were required to monitor injection flow rate, volume, and pressure. Other parameters specified in some of the permits include wellhead annulus pressure, initial and/or final totalizer reading, and pressure fall-off testing.

All permits/authorizations included mechanical integrity test (MIT) requirements and injectate monitoring requirements (either weekly, monthly, quarterly, and/or annually). In addition, all operators were required to monitor for pH, total dissolved solids (TDS), total suspended solids (TSS); chloride and conductivity. Other commonly noted parameters for monitoring among the permits/authorizations include temperature, sulfate, sodium, and Total Kjehldahl nitrogen (TKN) or nitrogen. Some permits/authorizations also required monitoring for gross alpha or radium-226/228 and other contaminants regulated under primary and secondary drinking water regulations (USEPA 2006c).

USEPA’s National Technical Work Group established minimum technical recommendations for the permitting of these wells in the future. The recommendations can be viewed at www.epa.gov/5water/uic/ntwg/dwtr_final_report_01-19-07.pdf.

These recommendations were meant to provide protection of the drinking water sources and public health, while allowing drinking water residual disposal. They contain stringent construction and monitoring requirements.


107

FEASIBILITY

The construction of an injection well can cost from $500,000 to

more than $1 million. Most of this cost is in the construction of the well, although the monitoring and maintenance costs are also substantial. Recognizing that this method may be cost prohibitive to small systems, the working group recommended that USEPA consider evaluating capacity building measures that would assist smaller systems in implementing this disposal option.

What Data are Needed to be Able to Use This Option?

In order to use this option, a water utility would need to apply

for a permit from the UIC coordinator for the USEPA region where the system is located. These are listed in Appendix A. As discussed above, it is possible that a permit could be granted for disposal in a Class I (nonhazardous), Class I (hazardous), Class II-R or Class V well. For a Class I (nonhazardous) well, no material could fail a TCLP, so in this case, TCLP data for all constituents would be required, as a minimum. There are no other parameters that are specifically addressed in the Federal UIC requirements, but the state UIC permit will certainly require more data, such as pH, TDS, quantity, etc. To date, no UIC injection well permits have been granted for drinking water treatment residuals containing radioactivity, but the federal UIC requirements do not specifically exclude them.

Each permit for an injection well for disposal of drinking water residuals would be addressed by the state UIC coordinator on a case by case basis.

Source: www.epa.gov

Class I well


109

CHAPTER 11

SUMMARY All drinking water treatment processes produce residuals. The purpose of this book is to raise awareness in small systems operations regarding the quantity and quality of this material. It is hoped that this awareness could help utilities choose the most appropriate method of treatment for contaminant removal by considering the limitations that residuals disposal might present. Further, by becoming aware of the quantity and quality of residuals produced, it is hoped that utility personnel would give careful consideration to minimizing the amount of residuals produced. It may also be possible through system optimization to stop the production of residuals that are characterized as hazardous. Residuals are inevitable in water treatment, but good environmental stewardship could reduce their adverse impact on the environment.


111

APPENDIX A

STATE, REGIONAL, FEDERAL, AND TRIBAL CONTACTS

Regional and State Drinking Water, UIC, and Radiation Control Contacts USEPA REGION 1

Drinking Water Drinking Water Program www.epa.gov/region1/eco/drinkwater (617)918-1111

UIC Underground Injection Control Program

www.epa.gov/region1/eco/drinkwater/pc_groundwater_discharges.html

(617)918-1111

Radiation Pesticides, Toxics, and Radiation Unit

www.epa.gov/region1/topics/pollutants/radioactivity.html

(617)918-1111

State Area Contact Web/Street Address Phone

Drinking Water

Department of Public Health: Drinking Water

Division

www.dph.state.ct.us/BRS/water/dwd.htm

(860)509-7333

UIC Connecticut Department of Environmental Protection

dep.state.ct.us/wtr (860)424-3018

CT

Radiation Division of Radiation, Department of

Environmental Protection

79 Elm Street Hartford, CT 06106-5127

Dep.state.ct.us/air2/prgacti.htm#Radiation

(860)424-3029

Drinking Water

Maine Department of Human Services: Division

of Health Engineering

www.state.me.us/dhs/eng/water (207)287-2070

UIC Maine Department of Environmental Protection

www.state.me.us/dep/blwq/docstand/uic/uichome.htm

(207)287-7814

ME

Radiation Radiation Control Program, Division of Health

Engineering

11 State House Station Augusta, ME 04333

www.state.me.us/dhs/eng/rad

(207)287-5677

Drinking Water

Department of Environmental Protection: Drinking Water Program

www.state.ma.us/dep/brp/dws/dwshome.htm

(617)292-5770

UIC Department of Environmental Protection

www.state.ma.us/dep/brp/dws/uic.htm (617)348-4014

MA

Radiation Radiation Control Program, Department of Public

Health

90 Washington Street Dorchester, MA 02121

www.state.ma.us/dph/rcp/radia.htm

(617)427-2944

Drinking Water

Department of Environmental Services:

Water Supply Engineering Bureau

www.des.state.nh.us/wseb (603)271-2513

UIC Department of Environmental Services

www.des.state.nh.us/dwspp (603)271-2858

NH

Radiation Radioactive Material Section, Bureau of

Radiological Health, Department of Health and

Human Services

Health and Welfare Building 6 Hazen Drive

Concord, NH 03301-6527 www.dhhs.state.nh.us/DHHS/RADHEA

LTH/default.htm

(603)271-4585

Drinking Water

Department of Health: Office of Drinking Water

Quality

www.health.ri.gov/environment/dwq/index.php

(401)222-6867

UIC Rhode Island Department of Environmental Management

www.state.ri.us/dem/programs/benviron/water

(401)222-3961

RI

Radiation Division of Occupational & Radiological Health,

3 Capitol Hill, Room 206 Providence, RI 02908-5097

(401)222-7755


112

Department of Health www.health.ri.gov/environment/occupational/index.php

Drinking Water

Department of Environmental

Conservation: Water Supply Division

www.vermontdrinkingwater.org (802)241-3400

UC Department of Environmental Conservation

www.anr.state.vt.us/dec/ww/uic.htm (802)241-4455

VT

Radiation Radiological Health, Department of Health

108 Cherry Street P.O. Box 70

Burlington, VT 05402 www.healthvermonters.info/hp/hp.shtml

#Anchor--Radiologic-1387

(802)865-7743

USEPA REGION 2

Drinking Water Division of Environmental Planning and Protection, Drinking Water Section

www.epa.gov/region02/water/drinkingwater

(212)637-5000

UIC Water Compliance Branch www.epa.gov/region02/capp (212)637-3766

Radiation Division of Environmental Planning and Protection, Radiation and Indoor Air

Branch

www.epa.gov/region02/org/depp.htm (212)637-4010


Drinking Water

Department of Environmental Protection: Bureau of Safe Drinking

Water

www.state.nj.us/dep/watersupply/safedrnk.htm

(609)292-5550

UIC Department of Environmental Protection,

Department of Water Quality

www.state.nj.us/dep/dwq/nonpoint.htm (609)633-7021

NJ

Radiation Radiation Protection Programs, Division of Environmental Safety, Health & Analytical

Programs, Department of Environmental Protection

P.O. Box 415 Trenton, NJ 08625-0415 www.state.nj.us/dep/rrp

(609)984-5636

Drinking Water

Department of Health: Bureau of Public Water

Supply Protection

www.health.state.ny.uss/nysdoh/water/main.htm

(518)402-7650

UIC USEPA Region 2 www.epa.gov/Region2/water/grndtop.htm

(212)637-4226

Radiological Health Unit, Division of Safety and Health, New York State

Dept. of Labor

NYS Office Campus, Building 12, Room 169

Albany, NY 12240

(518)457-1202

Radioactive Waste Policy and Nuclear Coordination, New York State Energy

Research & Development Authority

17 Columbia Circle Albany, NY 12203-6399

(518)862-1090

NY

Radiation

Radiation Section, Division 625 Broadway, 8th Floor (518)402-8579


113

of Hazardous Waste and Radiation Management,

New York State Department of Environmental

Conservation

Albany, NY 12333-7255 www.dec.state.ny.us/website/dshm/haza

rd/rad.htm

Bureau of Radiological Health, New York City Department of Health

Two Lafayette Street, 11th Floor New York, NY 10007

(212)676-1556

Bureau of Environmental Radiation Protection, New York State Department of

Health

547 River Street Troy, NY 12180-2216

(518)402-7550

Drinking Water

Department of Health: Public Waster Supply Supervision Program

www.epa.gov/region02/cepd/prlink.htm (787)977-5870

UIC Puerto Rico Environmental Quality Board

www.sso.org/ecos/states/delegations/pr.htm

(787)767-8073

PR

Radiation Radiological Health Division, Department of

Health

P.O. Box 70184 San Juan, PR 00936-8184

(787)274-7815

Drinking Water

Department of Planning & Natural Resources: Division of Environmental Protection

www.dpnr.gov.vi/dep/home.htm (340)773-1082

UIC USEPA Region 2 www.epa.gov/Region2/water/grndtop.htm

(212)637-4232

VI

Radiation N/A

USEPA REGION 3

Drinking Water Water Protection Division www.epa.gov/reg3wapd (215)814-2300

UIC Water Protection Division www.epa.gov/reg3wapd/drinkingwater/uic

(215)814-2300

Radiation Radiation Program www.epa.gov.reg3/radiation/radiation.htm

(215)814-2089


Drinking Water

Delaware Health & Social Services: Division of Public Health, Office of Drinking

Water

www.state.de.us/dhss/dph (302)741-8630

UIC Department of Natural Resources and

Environmental Control

www.dnrec.state.de.us/water2000/Sections/GroundWat/DWRGrndWat.htm

(302)739-4762

DE

Radiation Office of Radiation Control, Division of Public Health

P.O. Box 637 Dover, DE 19903

www.state.de.us/dhss/dph

(302)744-4546

Drinking Water

USEPA Region 3 www.epa.gov/reg3wapd/drinkingwater (202)535-2190

UIC USEPA Region 3 www.epa.gov/reg3wapd/drinkingwater/uic

(215)814-5445

DC

Radiation Department of Health, Environmental Health

Administration, Bureau of Food, Drug, and Radiation

Protection

51 N Street NE, Room 6025 Washington, DC 20002

(202)535-2188

MD Drinking Water

Department of the Environment: Public Water

www.mde.state.md.us/Programs/waterPrograms/Water_Supply/index.asp

(410)537-3000


114

Supply Program

UIC Department of the Environment

www.mde.state.md.us/Water (410)631-3323

Radiation Radiological Health Program, Air and Radiation

Management Administration, Maryland

Department of the Environment

1800 Washington Blvd Suite 750

Baltimore, MD 21230-1724 www.mde.state.md.us/Programs/AirPro

grams/Radiological_Health

(410)537-3300

Drinking Water

Department of Environmental Protection: Bureau of Water Supply

Management

www.dep.state.pa.us/dep/deputate/watermgt/wsm/wsm.htm

(717)787-5017


(215)814-5445

PA

Radiation Bureau of Radiation Protection, Department of Environmental Protection

P.O. Box 8469 Harrisburg, PA 17105-8469

www.dep.state.pa.us/dep/deputate/airwaste/rp/rp.htm

(717)787-2480

Drinking Water

Department of Health: Division of Water Supply Engineering, Office of

Drinking Water

www.vdh.state.va.us/dw (804)864-7500


(215)814-5445

VA

Radiation Radiological Health Program, Division of Health

Hazards Control, Department of Health

Main Street Station 1500 East Main, Room 240

Richmond, VA 23219 www.vdh.state.va.us/rad

(804)786-5932

Drinking Water

Bureau for Public Health: Environmental Engineering

Division

www.wvdhr.org/oehs/eed (304)558-2981

UIC Division of Environmental Protection

www.wvdep.org/item.cfm?ssid=11&ss1id=165

(304)558-6075

WV

Radiation Radiation, Toxics, & Indoor Air Division, Department of

Health and Human Resources

815 Quarrier Street, Suite 418 Charleston, WV 25301 www.wvdhhr.org/rita/

(304)558-6772

USEPA REGION 4

Drinking Water Water Management Division

www.epa.gov/region4/water (404)562-9345

UIC Water Management Division

www.epa.gov/region4/water/uic (404)562-9345

Radiation Air, Pesticides, and Toxic Management Division

www.epa.gov/region4/air/radon (404)562-9135


Drinking Water


Management: Water Supply Branch

www.adem/state.al.us/WaterDivision/WaterDiviosnPP.htm

(334)271-7773

UIC Department of Environmental Management

www.adem.state.al.us/WaterDivision/ground/UIC%20GW/GWUICInfo.htm

(334)271-7844

AL

Radiation Office of Radiation Control, Alabama Department of

201 Monroe Street, P.O. Box 303017 Montgomery, AL 36130-3017

(334)206-5391


115

Public Health www.adph.org/radiation

Drinking Water

Department of Environmental Protection: Drinking Water Section

www.dep.state.fl.us/water/drinkingwater (850)245-8624

UIC Department of Environmental Protection

www.dep.state.fl.us/water/uic/index.htm (850)921-9417

FL

Radiation Bureau of Radiation Control, Florida Department

of Health

4052 Bald Cypress Way, SE Bin C21 Tallahassee, FL 32399-1741

www.doh.state.fl.us/environment/radiation

(850)245-4266

Drinking Water

Department of Natural Resources: Drinking Water

Program

www.dnr.state.ga.us/dnr/environ (404)656-4087

UIC Environmental Protection Division

www.dnr.state.ga.us/dnr/environ (404)6563229

GA

Radiation Radioactive Materials Program, Environmental

Protection Division, Department of Natural

Resources

4244 International Parkway, Suite 114 Atlanta, GA 30354

www.ganet.org/dnr/environ/aboutepd_files/branches_files/rmprogram/default.htm

(404)362-2675

Drinking Water

Department of Environmental Protection: Drinking Water Branch

www.water.ky.gov/dw (502)564-3410

UIC USEPA Region 4 www.epa.gov/region4/water/uic (404)562-9452

KY

Radiation Radiation Health & Toxic Agents Branch, Cabinet for

Health Services, Department of Public

Health

275 East Main Street Mail Stop HS 2E-D

Frankfort, KY 40621-0001 Chs.ky.gov/publichealth/radiation.htm

(502)564-7818

Drinking Water

Department of Health: Division of Water Supply

www.msdh.state.ms.us/msdhsite (601)576-7518

UIC Department of Environmental Quality

www.deq.state.ms.us/MDEQ.nsf/page/Main_Home?OpenDocument

(601)961-5654

MS

Radiation Division of Radiological Health, State Department of

Health

3150 Lawson Street, P.O. Box 1700 Jackson, MS 39215-7100

www.msdh.state.ms.us/radiological

(601)987-6893

Drinking Water

Department of Environment and Natural Resources: Public Water Supply

Section

www.deh.enr.state.nc.us/pws (919)733-2321

UIC Department of Environment and Natural Resources

Gw.ehnr.state.nc.us/uic.htm (919)715-6165

NC

Radiation Division of Radiation Protection, Division of Environmental Health,

Department of Environment & Natural Resources

3825 Barrett Drive Raleigh, NC 27609-7221 www.drp.enr.state.nc.us

(919)571-4141

Drinking Water

Department of Health & Environmental Control:

Bureau of Water

www.scdhec.net/water/html/dwater.html (803)898-4300

UIC Department of Health & Environmental Control

www.scdhec.net/eqc/water/html/uic.html (803)898-3549

SC

Radiation Bureau of Radiological Health, Department of

Health & Environmental

2600 Bull Street Columbia, SC 29201

(803)545-4403


116

Control

Division of Waste Management, Bureau of

Land and Waste Management, Department of Health & Environmental

Control

2600 Bull Street Columbia, SC 29201

www.scdhec.net/lwm/html/radio.html

(804)896-4245

Drinking Water

Department of Environment & Conservation: Division

of Water Supply

www.state.tn.us/environment/dws (615)532-0191

UIC USEPA Region 4 www.epa.gov/region4/water/uic (404)562-9452

TN

Radiation Division of Radiological Health, Tennessee

Department of Environment and Conservation

L&C Annex, Third Floor 401 Church Street

Nashville, TN 37243-1532 www.state.tn.us/environment/rad

(615)532-0364

USEPA REGION 5

Drinking Water Water Division, Ground Water and Drinking Water

Branch

www.epa.gov/region5/water (312)886-6107

UIC Water Division, UIC Branch www.epa.gov/region5/water/uic/uic.htm (312)886-1492

Radiation Air and Radiation Division www.epa.gov/region5/air (312)353-2212


Drinking Water

Illinois Environmental Protection Agency:

Division of Public Water Supplies

www.epa.state.il.us/water/index-pws.html

(217)785-8653

UIC Illinois Environmental Protection Agency

www.epa.state.il.us/land/regulatory-programs/underground-injection-

control.html

(217)782-6070

IL

Radiation Division of Nuclear Safety, Illinois Emergency

Management Agency

1035 Outer Park Drive Springfield, IL 62704 www.state.il.us/idns

(217)785-9868

Drinking Water


Management: Drinking Water Branch

www.ai.org/idem/owm/dwb (317)232-8603

UIC USEPA Region 5 www.epa.gov/region5/water/uic/uic.htm (312)353-4543

IN

Radiation Indoor & Radiologic Health Division, State Department

of Health

2 N. Meridian Street, 5F Indianapolis, IN 46204-3003

www.state.in.us/isdh/regsvcs/radhealth/welcome.htm

(317)233-7146

Drinking Water

Department of Environmental Quality:

Drinking Water & Radiological Protection

Division

www.michigan.gov/deq (517)335-4716


MI

Radiation Hazardous Waste and Radiological Protection

Section, Waste and Hazardous Materials Division, Michigan

Department of

525 West Allegan Street P.O. Box 30241

Lansing, MI 48909-7741 www.michigan.gov/deq/0,1607,7-135-

3312_4120_4244---,00.html

(517)373-0530


117

Environmental Quality

Drinking Water

Department of Health: Drinking Water Protection

Section

www.health.state.mn.us/divs/eh/water (651)215-0770


MN

Radiation Section of Asbestos, Indoor Air, Lead and Radiation,

Division of Environmental Health, Department of

Health

121 E. Seventh Place, Suite 220 P.O. Box 64975

St. Paul, MN 55164-0975 www.health.state.mn.us/divs/eh/radiatio

n

(651)215-0945

Drinking Water

Ohio Environmental Protection Agency:

Division of Drinking & Ground Water

www.epa.state.oh.us/ddagw (614)644-2752

UIC Ohio Environmental Protection Agency

www.epa.state.oh.us/ddagw.uic.html (614)644-2771

OH

Radiation Bureau of Radiation Protection, Ohio

Department of Health

P.O. Box 118 Columbus, OH 43266-0118

(614)644-7860

Drinking Water

Department of Natural Resources: Bureau of

Water Supply

www.dnr.state.wi.us/org/water/dwg (608)266-0821

UIC Department of Natural Resources

dnr.wi.gov/org/water/dwg/Uiw/index.htm

(608)266-2438

WI

Radiation Radiation Protection Section, Division of Public

Health, Department of Health and Family Services

P.O. Box 2659 Madison, WI 53701-2659

www.dhfs.state.wi.us/dph_beh/RadiatioP/

(608)267-4792

USEPA REGION 6

Drinking Water Water Quality Protection Division, Drinking Water

Section

www.epa.gov/earth1r6/swp/drinkingwater/aboutq&a.htm

(214)665-7155

UIC Water Quality Protection Division, Source Water

Protection

www.epa.gov/earth1r6/6wq/swp/uic (214)665-7165

Radiation Multimedia Planning and Permitting Division

www.epa.gov/earth1r6/6pd/6pd.htm (214)665-8124


Drinking Water

Department of Health: Division of Engineering

www.healthyarkansas.com/eng (501)661-2623


www.adeq.state.ar.us/water/branch_permits/default.htm

(501)682-0646

AR

Radiation Division of Radiation Control & Emergency

Management, Radioactive Materials Program,

Department of Health

4815 West Markham Street Slot #30

Little Rock, AR 72205-3867

(501)661-2173

Drinking Water

Office of Public Health: Division of Environmental

& Health Services

www.oph.dhh.state.la.us/engineerservice/safewater

(225)765-5038


www.dnr.state.la.us (225)342-5561

LA

Radiation Permit Division, Office of Environmental Services

P.O. Box 4313 Baton Rouge, LA 70821-4313

(225)219-3005


118

www.deq.state.la.us/permits

Drinking Water

Environmental Department: Drinking Water Bureau

www.nmenv.state.nm.us/dwb/dwbtop.html

(505)827-7545

UIC Environment Department www.nmenv.state.nm.us/gwb/New%20Pages/UIC.htm

(505)827-2936

NM

Radiation Radiation Control Bureau, Environment Department

1190 St. Francis Drive, Room S2100 P.O. Box 26110

Santa Fe, NM 87502-0110 www.nmenv.state.nm.us/nmrcb/home.ht

ml

(505)476-3236

Drinking Water

Department of Environmental Quality: Water Quality Division

www.deq.state.ok.us/WQDnew (405)702-8100


www.deq.state.ok.us/LPDnew/uicindex.html

(405)702-5142

OK

Radiation Radiation Management Section, Oklahoma

Department of Environmental Quality

P.O .Box 1677 Oklahoma City, OK 73101-1677

(405)702-5155

Drinking Water

Texas Commission on Environmental Quality: Water Supply Division

www.tnrcc.state.tx.us/permitting/waterperm/pdw/pdw000.html

(512)239-4671

UIC Texas Commission on Environmental Quality

www.tceq.state.tx.us (512)239-6633

Bureau of Radiation Control, Texas Department

of Health

110 West 49th Street Austin, TX 78756-3189

www.tdh.state.tx.us/radiation/default.htm

(512)834-6679

TX

Radiation

Office of Permitting, Remediation &

Registration, Texas Commission on

Environmental Quality

P.O. Box 13087, MC 122 Austin, TX 78711-3087

www.tceq.state.tx.us/AC/about/organization/oprr.html

(512)239-6731

USEPA REGION 7

Drinking Water Water Division www.epa.gov/region07/water/dwgw.htm

(913)551-7003

UIC Water Division www.epa.gov/region07/water (913)551-7003

Radiation Radiation, Asbestos, Lead, and Indoor Programs

Branch

www.epa.gov/region07/topics.htm (913)551-7003


Drinking Water

Department of Natural Resources: Water Supply

Section

www.state.ia.us/epd/wtrsuply/wtrsup.htm

(515)725-0275

UIC USEPA Region 7 www.epa.gov/Region7/water/contact.htm

(913)551-7413

IA

Radiation Bureau of Radiological Health, Iowa Department of

Public Health

401 SW 7th Street, Suite D Des Moines, IA 50309

www.idph.state.ia.us/eh/radiological_health.asp

(515)281-3478

Drinking Water

Department of Health and Environment: Public Water

Supply Section

www.kdhe.state.ks.us/pws (785)296-5514 KS

UIC Department of Health and www.kdhe.state.ks.us/uic (785)296-5509


119

Environment

Radiation Radiation and Asbestos Control, Kansas Department of Health & Environment

1000 SW Jackson, Suite 320 Topeka, KS 66612-1366

www.kdhe.state.ks.us/radiation

(785)296-1565

Drinking Water

Department of Natural Resources: Public Drinking

Water Program

www.dnr.state.mo.us/wpscd/wpcp (573)751-5331


www.dnr.state.mo.us/homednr.htm (573)368-2170

MO

Radiation Division of Environmental Health, Department of

Health and Senior Services

930 Wildwood Drive, P.O. Box 570 Jefferson City, MO 65102-0570

www.dhss.state.mo.us/RadProtection

(573)751-6112

Drinking Water

Department of HHS Regulation & Licensure

www.hhs.state.ne.us/enh/pwsindex.htm (402)471-2541


www.deq.state.ne.us (402)471-2186

NE

Radiation Radiation Control Programs P.O. Box 95007 Lincoln, NE 68509-5007

www.hhs.state.ne.us/rad/radindex.htm

(402)471-2079

USEPA REGION 8

Drinking Water Drinking Water Program

www.epa.gov/region08/water/dwhome/dwhome.html

(303) 312-6812

UIC UIC Program www.epa.gov/region08/water/uic (303) 312-6312

Radiation Radiation Protection Program

www.epa.gov/Region8/search/alpha.html#R

(303) 312-6312


Drinking Water

Department of Public Health & Environment: Drinking

Water Program

www.cdphe.state.co.us/wq/wqhom.asp (303) 692-3500

UIC USEPA Region 8 www.epa.gov/Region8/water/uic (303) 312-6125

CO

Radiation Radiation Management Program, HMWMD-B2, Hazardous Materials &

Waste Management Division, Department of

Public Health & Environment

4300 Cherry Creek Drive South Denver, CO 80246-1530

www.cdphe.state.co.us/hm/rad/radiationservices.asp

(303) 692-3428

Drinking Water


Public Water Supply Section

www.deq.state.mt.us/wqinfo (406) 444-3080


MT

Radiation Radiological Health Program, Department of Public Health & Human

Services, Licensure Bureau

2401 Colonial Drive P.O. Box 202953 Helena, MT 59620-2953

(406) 444-1510

Drinking Water

Department of Health: Division of Municipal

Facilities

www.ehs.health.state.nd.us/ndhd/environ/mf

(701) 328-5211

UIC Department of Health www.health.state.nd.us/wq/gw/uic.htm (701) 328-5233

ND

Radiation Division of Air Quality, North Dakota Department

of Health

1200 Missouri Avenue, Rm 304 P.O. Box 5520 Bismarck, ND 58506-5520

www.health.state.nd.us/ndhd/environ/ee/rad/rad.htm

(701) 328-5188

SD Drinking Department of Environment

www.state.sd.us/denr/des/drinking/dwp (605) 773-3754


120

Water & Natural Resources: Drinking Water Program

rg.htm


Radiation Office of Health Care Facilities, Licensure & Certification, Systems

Development and Regulations

615 East 4th Street Pierre, SD 57501-1700

(605) 773-3356

Drinking Water


Division of Drinking Water

www.drinkingwater.utah.gov (801) 536-4200

UIC Department of

Environmental Quality waterquality.utah.gov (801) 538-6023

UT

Radiation Division of Radiation Control, Department of Environmental Quality

168 North 1950 West P.O. Box 144850 Salt Lake City, UT 84114-4850

www.eq.state.ut.us/EQRAD/drc_hmpg.htm

(801) 536-4250

Drinking Water

USEPA Region 8: Wyoming Drinking Water Program

www.epa.gov/region08/water/dwhome/wycon/wycon.html

(307) 777-7781

UIC Department of

Environmental Quality deq.state.wy.us/wqd/index.asp?pageid=

56 (307) 777-7095

WY

Radiation Solid & Hazardous Waste Division, Department of Environmental Quality

Herschler Building, 4E Cheyenne, WY 82002

deq.state.wy.us/shwd

(307) 777-7753

USEPA REGION 9

Drinking Water Water Division www.epa.gov/region09/water (415) 947-8707

UIC Water Division www.epa.gov/region09/water (415) 947-8707

Radiation Radiation Protection Program

www.epa.gov/region09/air/radiation (415) 947-4197


Drinking Water

Environmental Protection Agency: American Samoa

www.epa.gov/Region9/cross_pr/islands/samoa.html

(415) 972-3767

UIC USEPA Region 9 www.epa.gov/region09/water/undergrou

nd/notes (415) 972-3767

AS

Radiation N/A

Drinking Water


Drinking Water Monitoring & Assessment Section

www.adeq.state.az.us/environ/water/dw (602) 771-2303


nd/notes (415) 972-3767

AZ

Radiation Arizona Radiation Regulatory Agency

4814 South 40th Street Phoenix, AZ 85040

www.arra.state.az.us

(602) 255-4845

Drinking Water

Department of Health Services: Division of Drinking Water &

Environmental Management

www.dhs.ca.gov (916) 449-5577


nd/notes (415) 972-3767

CA

Radiation Radiologic Health Branch, Division of Food, Drugs, and Radiation Safety, California Department of Health

15 Capitol P.O. Box 997414, MS 7610 Sacramento, CA 95899-7414

www.dhs.ca.gov/RHB/default.htm

(916) 440-7899


121

Services

Drinking

Water

Guam Environmental Protection Agency

www.epa.gov/region09/cross_pr/islands/guam.html

(671) 972-3770


nd/notes (415) 972-3767

GU

Radiation N/A

Drinking Water

Department of Health: Environmental Management

Division

www.hawaii.gov/health/eh/sdwb (808) 586-4258


nd/notes (415) 972-3767

HI

Radiation Noise, Radiation & IAQ Branch, Department of

Health

591 Ala Moana Boulevard Honolulu, HI 96813-4921

www.hawaii.gov/health/environmental/noise/index.html

(808) 586-4700

Drinking Water

Department of Human Resources: Bureau of Health

Protection Services

health2k.state.nv.us/bhps/phe/sdwp.htm (775) 687-6615

UIC Department of

Environmental Protection ndep.state.nv.us/bwpc/uic01.htm (775) 687-4670

NV

Radiation Radiological Health Program, Bureau of Health Protection Services, Nevada State Health Division

1179 Fairview Drive, Suite 102 Carson City, NV 89701-5405

health2k.state.nv.us/BHPS/rhs

(775) 687-5394

USEPA REGION 10

Drinking Water Drinking Water Unit yosemite.epa.gov/R10/WATER.NSF/Drinking+Water/Abo ut+DWU

(206) 553-8515

UIC Underground Injection Control Program

yosemite.epa.gov/R10/WATER.NSF/UIC/UIC+Program

(206) 553-1673

Radiation Radiation Program

yosemite.epa.gov/R10/Airpage.nsf/webpage/Radiation

(206) 553-7660


Drinking Water

Department of Environmental Conservation:

Drinking Water & Wastewater Program

www.state.ak.us/dec/eh/dw (907) 269-7647

UIC USEPA Region 10 Ground

Water Protection Unit www.epa.gov/region10 (206) 553-1900

AK

Radiation Radiological Health Program, Section of Laboratories, State of

Alaska/DH&SS

4500 Boniface Parkway Anchorage, AK 99507-1270

www.hss.state.ak.us/dph/labs/radiological/radiological_healt h.htm

(907) 334-2107

Drinking Water

Department of Environmental Quality: Water Quality Division

www.deq.state.id.us/water/prog_issues.cfm

(208) 373-0502

UIC Department of Water

Resources www.idwr.state.id.us (208) 327-7956

ID

Radiation Department of Environmental Quality

900 N. Skyline, Suite C Idaho Falls, ID 83402

www.deq.state.id.us

(208) 528-2617

Drinking Water

Department of Human Resources: Drinking Water

Program

www.ohd.hr.state.or.us/dwp (503) 731-4317 OR

UIC Department of www.deq.state.or.us/wq/groundwa/uich (503) 229-5945


122

Environmental Quality ome.htm

Radiation Radiation Protection Services, Oregon Health Services, Department of

Human Services

800 NE Oregon Street, Suite 260 Portland, OR 97232-2162 www.ohd.hr.state.or.us/rps

(503) 731-4014

Drinking Water

Department of Health: Drinking Water Division

www.doh.wa.gov/ehp/dw (360) 236-3100

UIC Department of Ecology www.ecy.wa.gov/programs/wq/grndwtr/

uic (360) 407-6143

WA

Radiation Office of Radiation Protection, Division of Environmental Health, Department of Health

7171 Cleanwater Lane, Bldg #5 P.O. Box 47827 Olympia, WA 98504-7827 www.doh.wa.gov/ehp/rp

(360) 236-3210

Source: USEPA 2005


123

APPENDIX B

TCLP CONTAMINANTS AND REGULATORY LEVELS

Contaminant

Regulatory threshold level (mg/L)

Arsenic 5.0 Barium 100.0

Cadmium 1.0 Chromium 5.0

Lead 5.0 Mercury 0.2 Selenium 1.0

Silver 5.0 Endrin 0.02 Lindane 0.4

Methoxychlor 10.0 Toxaphene 0.5

2,4-D 10.0 2,4,5-TP 1.0 Chlordane 0.03

Heptachlor (and its expoxide) 0.008 Benzene 0.5

Carbon tetrachloride 0.5 Chlorobenzene 100.0 Chloroform 6.0

1,2-Dichloroethane 0.5 1,1-Dichloroethylene 0.7 Methyl ethyl ketone 200.0 Tetrachloroethylene 0.7 Trichloroethylene 0.5

Vinyl chloride 0.2 1,4-Dichlorobenzene 7.5 Hexachlorobenzene 0.13 Hexachlorobutadiene 0.5 2,4-Dinitrotoluene 0.13 Hexachloroethane 3.0

Nitrobenzene 2.0 Pyridine 0.5 o-Cresol 200.0 m-Cresol 200.0 p-Cresol 200.0

Pentachlorophenol 100.0 2,4,5-Trichlorophenol 400.0 2,4,6-Trichlorophenol 2.0


125

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ABBREVIATIONS

AA activated alumina AEA Atomic Energy Act AOR area of review AWWA American Water Works Association (Denver, CO) AwwaRF AWWA Research Foundation (Denver, CO) AX anion exchange BAT best available technology BOD biochemical oxygen demand CaWET California Waste Extraction Test CCL contaminant candidate list CERCLA Comprehensive Environmental Response, Compensation, and

Liability Act CESQG conditionally exempt small quantity generator CF coagulation-filtration CFR Code of Federation Register CMF coagulation-microfiltration COD chemical oxygen demand CWA Clean Water Act CWS community water system CX cation exchange D/DBP Disinfectants/Disinfection Byproducts Rule DEQ Department of Environmental Quality DOT Department of Transportation DWTP drinking water treatment plant EBCT empty bed contact time ED electrodialysis EDR electrodialysis reversal EPA environmental protection agency EQ equalization FBRR Filter Backwash Recycle Rule (part of Surface Water Treatment

Rule FRDS Federal Reporting Data System GAC granular activated carbon gpm gallons per minute GWUBI groundwater under direct influence IBS iron-based sorbents IX ion exchange


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LDR land disposal requirements LLRW low level radioactive waste LLRWF low level radioactive waste facilities LQG large quantity generators MCL maximum contaminant level MF microfiltration membranes MG million gallons mgd million gallons per day MSWLF municipal solid waste landfill NaCl sodium chloride NCWS non-community water systems NF nanofiltration membranes NPDES National Pollutant Discharge Elimination System NRC nuclear regulatory commission NTNCWS non-transient, non-community water systems OGWDW Office of Ground Water and Drinking Water PAC powered activation carbon POTW publicly owned treatment works RCRA Resource Conservation and Recovery Act RO reverse osmosis SFBW spent filter backwash SDWA Safe Drinking Water Act SOC synthetic organic compounds SPARRC Spreadsheet Program to Ascertain Radionuclides Residuals

Concentration SPDES State Pollutant Discharge Elimination System SQG small quantity generators SSCT small system compliance technology TCLP toxicity characteristic leaching procedure TDS total dissolved solids (TS – TSS) TENORM technologically enhanced naturally occurring radioactive materials TKN total Kjehldahl nitrogen TNCWS transient non-community water systems TSDF treatment, storage, disposal facility UF ultrafiltration membranes UIC underground injection control USEPA United States Environmental Protection Agency USDW underground source of drinking water


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WTP water treatment plant ZEI zone of endangering influence


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