EPA815-R-00-011
DRAFT
SMALL SYSTEM COMPLIANCE TECHNOLOGY LIST
FOR THE ARSENIC RULE
TARGETING AND ANALYSIS BRANCH
STANDARDS AND RISK MANAGEMENT DIVISION
OFFICE OF GROUND WATER AND DRINKING WATER
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C.
NOVEMBER 1999
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TABLE OF CONTENTS
1.0 INTRODUCTION 1-1
1.1 Assessment of Treatment Technologies Under the SDWA 1-1
1.2 Development of Compliance Technology Lists 1-3
1.3 Statutory Requirements 1-5
1.4 Format of the Small System Compliance List for Arsenic Removal 1-6
1.4.1 EPA Office of Research and Development 1-6
1.4.2 The National Drinking Water Clearinghouse (NDWC) 1-7
1.5 Document Organization 1-7
2.0 EVALUATED COMPLIANCE TECHNOLOGIES 2-1
2.1 Introduction 2-1
2.2 Selection of Removal Technologies 2-2
2.3 Treatment Processes 2-3
3.0 COMPLIANCE TECHNOLOGY DESCRIPTIONS 3-1
3.1 Introduction 3-1
3.2 Removal Technologies 3-1
3.2.1 Enhanced Lime Softening 3-1
3.2.2 Enhanced Coagulation/Filtration 3-3
3.2.3 Anion Exchange 3-4
3.2.4 Activated Alumina 3-6
3.2.5 Reverse Osmosis 3-8
3.2.6 Coagulation-Assisted Microfiltration 3-9
3.2.7 Greensand Filtration 3-10
3.2.8 Point-of-Entry and Point-of-Use Treatment 3-12
3.2.8.1 Activated Alumina 3-13
3.2.8.2 Reverse Osmosis 3-14
3.2.9 Regionalization 3-15
3.2.10 Alternate Source 3-17
3.3 Residuals Handling and Disposal 3-18
3.3.1 Landfill Disposal 3-19
3.3.2 Publicly-Owned Treatment Works 3-21
3.3.3 Evaporation Ponds 3-22
3.3.4 Chemical Precipitation 3-23
3.3.5 Mechanical Dewatering 3-24
3.3.6 Non-Mechanical Dewatering 3-25
3.4 Pre-Oxidation Processes 3-27
3.4.1 Chlorination 3-27
3.4.2 Potassium Permanganate 3-28
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Bpulevard, 12th Floor
Chicago, IL 60604-3590
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4.0 NATIONAL-LEVEL AFFORDABILITY DETERMINATION 4-1
4.1 Distinctions Between National- and System-Level Affordability 4-1
4.2 Role of National-Level Affordability Criteria 4-2
4.3 Unit of Measure for the National-Level Affordability Criteria 4-2
4.4 Derivation of the National-Level Affordability Criteria 4-4
4.5 Determination of Household Affordability 4-8
4.6 Residuals Handling and Disposal Costs / 4-33
5.0 REFERENCES : 5-1
APPENDIX A Relevant Parts of Section 1412 of the 1996 SDWA Amendments A-l
APPENDIX B Relevant Parts of Section 1415 of the 1996 SDWA Amendments B-l
LIST OF TABLES
2-1 Treatment Trains Evaluated for Arsenic Removal 2-4
4-1 Residential Consumption at Small Water Systems 4-4
4-2 Summary of Select Consumer Expenditures for All Consumer Units (1995 $) 4-6
4-3 National Level Affordability Criteria 4-7
4-4 Affordability Assessment of Technologies Examined for Removal
of Arsenic Contamination 4-9
LIST OF FIGURES
1-1 Affordable Compliance Technologies Flowchart 1-4
n
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ACRONYMS
AA Activated alumina
AWWA American Water Works Association
AWWARF American Water Works Association Research Foundation
BAT Best Available Technology
BOD Biological oxygen demand
BV Bed volume
CES Consumer expenditure survey
C/F Coagulation/filtration
CPI Consumer price index
CWS Community Water System
CWSS Community Water System Survey
DBF Disinfection by-product
DMAA Dimethyl arsenic acid
EBCT Empty bed contact time
EDR Electrodialysis reversal
EPA United States Environmental Protection Agency
ETVP Environmental Technology Verification Program
GAC Granular activated carbon
gpd Gallons per day
IOCS Iron oxide coated sand
IX Ion exchange
kgal Thousand gallons
kgpd Thousand gallons per day
LS Lime softening
111
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MCL
MCLG
MF
mg/L
mgd
MHI
MMAA
NDWC
NF
NOM
NIPDWR
NPDES
NPDWR
NSFI
O&M
OGWDW
ORD
POE
POTW
POU
PVC
RCRA
RESULTS
RO
SDWA
SWTR
Maximum Contaminant Level
Maximum Contaminant Level Goal
Microfiltration
Milligrams per liter
Million gallons per day
Median household income
Monomethyl arsenic acid
National Drinking Water Clearinghouse
Nanofiltration
Natural organic matter
National Interim Primary Drinking Water Regulation
National Pollutant Discharge Elimination System
National Primary Drinking Water Regulation
National Sanitation Foundation International
Operations and maintenance
Office of Ground Water and Drinking Water
Office of Research and Development
Point-of-entry
Publicly-owned treatment works
Point-of-use
Polyvinyl chloride
Resource Conservation and Recovery Act
Registry of Equipment Suppliers of Treatment Technologies for Small
Systems
Reverse osmosis
Safe Drinking Water Act
Surface Water Treatment Rule
IV
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TBLL Technically Based Local Limits
TCLP Toxicity Characteristic Leaching Procedure
TDS Total dissolved solids
TOC Total organic carbon
TSS Total suspended solids
UF Ultrafiltration
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1.0 INTRODUCTION
1.1 ASSESSMENT OF TREATMENT TECHNOLOGIES UNDER THE SDWA
The 1986 Safe Drinking Water Act (SDWA or the Act) identified a process for setting
maximum contaminant levels (MCLs) as close to the maximum contaminant level goal (MCLG) as
feasible. The Act states that "...the term 'feasible' means feasible with the use of the best
technology, treatment techniques and other means which the Administrator finds, after examination
for efficacy under field conditions and not solely under laboratory conditions, are available (taking
cost into consideration)" [Section 1412(b)(4)(D)]. The technologies that meet this feasibility
criterion, called "best available technologies," or BATs, are listed in the final regulations. This
process was retained in the 1996 SDWA.
Prior to the 1996 Amendments, cost assessments for treatment technology feasibility
determinations were based upon impacts to regional and large metropolitan water systems. This
approach was originally established when the SDWA was enacted in 1974 [H.R. Rep. No. 93-1185
at 18(1974)] and upheld by the 1986 Amendments [132 Cong. Rec. S6287 (May 21,1986)]. The
size categories used by EPA in making feasibility determinations for regional and large metropolitan
water systems have varied by regulation. The two most common size categories used were those
including systems serving 50,000 to 75,000 people and 100,000 to 500,000 people. The technical
demands and costs associated with technologies deemed feasible based on impacts to regional and
large metropolitan water systems often make these technologies inappropriate for small systems.
The 1996 Amendments attempted to redress this problem in part by requiring EPA to assess
technologies with respect to small public water systems for compliance with existing and future
regulations. The Amendments require EPA to perform technology assessments for three categories
of small public water systems: systems serving 25 to 500 people; 501 to 3,300 people; and 3,301
to 10,000 people. In total, small systems include more than 90 percent of all community water
systems (CWSs) within the regulatory domain of the SDWA.
The 1996 Amendments identify two classes of technologies for small systems: compliance
technologies and variance technologies. A compliance technology is defined as a technology or
other means that is affordable and achieves compliance with an MCL or satisfies a treatment
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technique requirement. Potential compliance technologies include packaged or modular systems and
point-of-entry (POE) or point-of-use (POU) treatment units [see 1996 SDWA Section
1412(b)(4)(E)(ii)]. Variance technologies are specified for those system size category/source water
quality combinations for which there are no listed compliance technologies [1996 SDWA Section
1412(b)(15)(A)]. Thus, the specification of compliance technologies for a given system size
category/source water quality combination prohibits listing variance technologies for the same
combination.
While variance technologies may not achieve compliance with a. particular MCL or treatment
technique requirement, they must achieve the maximum reduction or inactivation efficiency
affordable, taking into consideration system size and source water quality. Variance technologies
must also achieve a level of contaminant reduction that is protective of public health [1996 SDWA
Section 1412(b)(15)(B)]. In addition to differentiating variance technologies and compliance
technologies, the 1996 Amendments also provide flexibility by allowing systems to apply for and
be granted variances prior to the installation of a variance technology. This ensures that a system
will have secured a variance before investing in the appropriate variance technology.
For systems serving 3,301 to 10,000 people, EPA approval is required before a small system
variance may be granted. However, a system in either of the two smallest system size categories
(i.e., systems serving 25 to 500, and 501 to 3,300 people) may apply for a variance as long as no
affordable compliance technologies are listed by EPA for the applicable combination of small system
size category and source water quality. To obtain a variance, such a system must install the variance
technology listed for its specific system size category/source water quality combination [Section
1415(e)(2)(A)]. A small system variance may only be obtained if alternate source, treatment, and
restructuring options are unaffordable at the system-level. Furthermore, no variance technologies
will be listed for contaminants meeting the following specifications:
Small system variances are not available for any MCL or treatment technique specified
for a contaminant with respect to which a National Primary Drinking Water Regulation
(NPDWR) was promulgated prior to January 1, 1986 [1996 SDWA Section
Small system variances are not available for any contaminant for which a NPDWR was
promulgated before 1986, but was retained or increased since then.
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Small system variances are not available for MCLs or treatment techniques established
by any NPDWR which applies to microbial contaminants or indicators of microbial
contaminants, including bacteria, viruses, or other microbial pathogens [1996 SDWA
Section 1415(e)(6)(B)].
For future regulations, a system that is not eligible for a variance based on the requirements
outlined above, may seek an exemption, engage in regionalization activities, or develop an alternate
source (see Figure 1-1). However, new exemptions will only be available for newly-named
contaminants. States may not grant new exemptions for existing regulations. Those small systems
with existing exemptions for these rules may continue to apply for renewals until the exemption
period has expired (i.e., a small system will have a maximum of nine years following the compliance
date to meet applicable MCLs or treatment techniques, even if the exemption was issued prior to the
1996 SDWA Amendments).
1.2 DEVELOPMENT OF COMPLIANCE TECHNOLOGY LISTS
The 1996 Amendments require EPA to develop two lists of compliance technologies for
existing MCLs and treatment technique requirements. The first, a list of technologies for achieving
compliance with the Surface Water Treatment Rule (SWTR) for each of the three size categories of
small water system, was published in the Federal Register on August 11, 1997. The 1996
Amendments set a deadline for the list of technologies that achieve compliance with MCLs and
treatment technique requirements of other existing NPDWRs for August 6, 1998. When variance
technologies are listed, EPA is required to list any assumptions used in determining affordability,
taking into consideration the population served [Section 1412(b)(l 5)(C)]. As mentioned previously,
small system variances are not available for all contaminants. Where small system variances are
precluded by the SDWA, variance technologies will not be listed.
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Figure 1-1
Affordable Compliance Technologies^
System Out of
Compliance
/^Affordable Compli;
Technology?
No
tes
X \
/Can System Afford^
-< a Compliance
Technology?
No
No
X \
/ Can System Afford ^
Treatment, Alt. Source or
Restructuring?
/ \
X Can System x^
X Restructure or Afford
\ Alt Source?
v/
No
i
Implement
Treatment, Alt
Source or
Restructuring
^
~t
No
> k
k.
^fes
A
\
* Note: Thisappioach wasoriginaBy presented in B3\ 1998.
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Although the SDWA is silent concerning whether small system compliance technologies for
existing regulations should be affordable, EPA has determined that affordability determinations are
appropriate for all future and existing regulations where the SDWA permits the listing of variance
technologies. If candidate technologies are not evaluated against an affordable technology criterion,
compliance technologies would exist for all current regulations, regardless of source water quality.
As a result, existing BATs or treatment techniques would become the compliance technologies for
small systems, as was the case prior to the 1996 Amendments. EPA's interpretation of
Congressional intent in the SDWA is that the Agency should evaluate small system technologies
against an affordable technology criterion for those existing regulations where small system
variances or variance technologies are not prohibited by the SDWA. Furthermore, to maximize the
compliance information available to small systems, whenever affordable compliance technologies
are identified, EPA will also list technologies that can achieve compliance but do not meet the
affordability criterion.
13 STATUTORY REQUIREMENTS
In 1976 EPA issued a National Interim Primary Drinking Water Regulation (NIPWDR) for
arsenic at 50 parts per billion (ppb or fJ.g/L). Under the 1986 amendments to the SDWA, Congress
directed EPA to publish MCLGs and promulgate NPDWRs for 83 contaminants, including arsenic.
When EPA missed the statutory deadline for promulgating an arsenic regulation, a citizens' group
filed suit to compel EPA to do so; EPA entered into a consent decree to issue the regulation. The
EPA Office of Ground Water and Drinking Water (OGWDW) held internal workgroup meetings
throughout 1994, addressing risk assessment, treatment, analytical methods, arsenic occurrence,
exposure, costs, implementation issues, and regulatory options before deciding in early 1995 to defer
the regulation in order to better characterize health effects and treatment technology.
With the reauthorization of the SDWA on August 6, 1996, Congress added section
1412(b)(12)(A) to the act. This addition specifies, in part, that EPA propose a NPDWR for arsenic
by January 1,2000 and issue a final regulation by January 1,2001.
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1.4 FORMAT OF THE SMALL SYSTEM COMPLIANCE TECHNOLOGY LIST
FOR ARSENIC REMOVAL
The 1996 SDWA does not specify the format or content for compliance technology lists.
Section 1412(b)(15)(D) states that the variance technology lists can be issued either through
guidance or regulations. EPA believes it appropriate to provide compliance technology lists in the
form of guidance rather than through regulations. Since the listing provided in this guidance is
meant to be informational and interpretative, it does not require any changes to existing rules or the
promulgation of new ones. The purpose of this guidance is to provide small systems with
information concerning the types of technologies that can be used to comply with existing, proposed,
and potential regulations promulgated to control arsenic in drinlcing water. However, the
information presented in this document does not override any existing regulatory requirements.
This listing provides details on the capabilities, applicability ranges, water quality concerns,
and operational and maintenance requirements for the identified compliance technologies. The
listing will be updated in the future as necessary. The listing does not contain information on
specific products since OGWDW does not have the resources necessary to review individual
products for each potential application. Furthermore, this function is not in EPA's area of purview.
Information on specific products may be available through the following sources.
1.4.1 EPA Office of Research and Development (ORD)
In conjunction with the National Sanitation Foundation International (NSFI), ORD is
conducting a pilot project under the Environmental Technology Verification Program (ETVP). The
goal of the project is to produce a central source of information for treatment purchasers with
performance data from independent third party organizations. The project will provide a mechanism
for verification testing of packaged drinking water treatment systems for community and commercial
needs. Components of the project include (1) development of verification protocols and test plans;
(2) independent testing and validation of packaged equipment; (3) partnering among verification
entities to obtain credible cost and performance data; and (4) preparation of product verification
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reports for widespread distribution. For more information on this project, consult the ETVP website
at http://www.nsf.org/verification/verification.html.
1.4.2 The National Drinking Water Clearinghouse (NDWC)
The NDWC, located at West Virginia University, maintains and distributes the Registry of
Equipment Suppliers of Treatment Technologies for Small Systems (RESULTS) database.
RESULTS was designed as an electronic means to access data on small water treatment systems
employing both conventional and non-conventional treatment technologies. The database includes
information and on-site contacts for included technologies. NDWC can be reached by phone at
(304) 293-4191 or via the Internet at http://www.ndwc.wvu.edu.
1.5 DOCUMENT ORGANIZATION
Section 2 contains a list of evaluated technologies and provides useful information on the
technologies evaluated for this compliance listing. Chapter 3 contains detailed descriptions of the
evaluated technologies, including descriptions of capabilities and operational considerations.
Affordability determinations for the evaluated technologies are presented in Chapter 4.
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2.0 EVALUATED COMPLIANCE TECHNOLOGIES
2.1 INTRODUCTION
Arsenic (As) is a naturally occurring element present in food, water, and air. Known for
centuries to be an effective poison, some animal studies suggest that arsenic may be an essential
nutrient at low concentrations. Non-malignant skin alterations, such as keratosis and hypo- and
hyper-pigmentation, have been linked to arsenic ingestion, and skin cancers have developed in some
patients. Additional studies indicate that arsenic ingestion may result in internal malignancies,
including cancers of the kidney, bladder, liver, lung, and other organs. Vascular system effects have
also been observed, including peripheral vascular disease, which in its most severe form results in
gangrene or Blackfoot Disease. Other potential effects include neurologic impairment (Lomaquahu
and Smith, 1998).
The primary route of exposure to arsenic for humans is ingestion. Exposure via inhalation
is considered minimal, though there are regions where elevated levels of airborne arsenic occur
periodically (Hering and Chiu, 1998). Arsenic occurs in two primary forms; organic and inorganic.
Organic species of arsenic are predominantly found in foodstuffs, such as shellfish, and include such
forms as monomethyl arsenic acid (MMAA), dimethyl arsenic acid (DMAA), and arseno-sugars.
Inorganic arsenic occurs in two valence states, arsenite (As HI) and arsenate (As V). As(III) species
consist primarily of arsenious acid (H3AsO3) in natural waters. As(V) species consist primarily of
H2AsO4" and HAsO42" in natural waters (Clifford and Lin, 1995). Most natural waters contain the
more toxic inorganic forms of arsenic. Natural groundwaters contain the more toxic As(III) (among
the inorganic species) as reducing conditions prevail. In natural surface waters As(V) is the
dominant species. Arsenic removal technologies for drinking water are described in Technologies
and Costs for the Removal of Arsenic from Drinking Water (Draft) (EPA, 1999). These technologies
include:
Precipitative. processes, including coagulation/filtration (C/F), direct filtration,
coagulation assisted microfiltration, enhanced coagulation, lime softening (LS), and
enhanced lime softening.
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Adsorption processes, including activated alumina (AA), and iron oxide coated sand
(IOCS).
Ion exchange (IX) processes, specifically anion exchange.
Membrane filtration, including microfiltration (MF), ultraf iltration (UF), nanofiltration
(NF), reverse osmosis (RO), and electrodialysis reversal (EDR).
Alternative treatment processes, including biological processes, granular ferric
hydroxide, sulfur-modified iron and iron filings, and greensand filtration.
Point-of-entry (POE) and point-of-use (POU) devices.
2.2 SELECTION OF REMOVAL TECHNOLOGIES
The removal technologies selected for evaluation of affordability are listed below. These
technologies have been shown through bench-, pilot-, and demonstration-scale studies to be effective
in the removal of arsenic compounds from drinking water (EPA, 1999). Summary descriptions of
the selected technologies are provided in Section 3.0 of this document.
Enhanced lime softening
Enhanced coagulation/filtration
» Anion exchange
Activated alumina
Reverse osmosis
Coagulation-assisted microfiltration
Greensand filtration
POE activated alumina
POU activated alumina
POU reverse osmosis
Regionalization
Alternate source
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2.3 TREATMENT PROCESSES
The removal technologies listed above were combined with selected pre-oxidation treatment,
corrosion control, and residuals handling and waste removal techniques to identify treatment
processes to be evaluated for arsenic removal. Pre-oxidation treatment is provided by the addition
of either permanganate or chlorine. Corrosion control is provided by the addition of lime. Residuals
handling and waste removal techniques applicable to the selected removal technologies include the
following:
" Non-hazardous landfill disposal.
Publicly-owned treatment works (POTW) disposal.
Direct disposal.
Evaporation pond.
Chemical precipitation.
Mechanical dewatering.
Non-mechanical dewatering.
The affordability of arsenic removal from drinking water is evaluated in this document for
several combinations of treatment, pre-oxidation, corrosion control, and waste disposal technologies,
referred to here as "treatment trains." The treatment trains selected for evaluation are shown in Table
2-1. The treatment and disposal technologies are described in Section 3.0.
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Table 2-1
Treatment Trains Evaluated for Arsenic Removal
Treatment Process
Enhanced Lime Softening
Enhanced Coagulation/Filtration
Anion Exchange (25 mg/1 SO4)
Anion Exchange (150 mg/1 S04)
Anion Exchange (25 mg/1 SO4)
Anion Exchange (150 mg/1 SO4)
Anion Exchange (25 mg/1 SO4)
Anion Exchange (150 mg/1 SO4)
Activated Alumina (3,000 BV)
Activated Alumina (7,000 BV)
Activated Alumina (16,500 BV)
Activated Alumina (3,000 BV)
Activated Alumina (7,000 BV)
Activated Alumina (1 6,500 BV)
Preoxidation
Chlorine
Permanganate
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Chlorine
Corrosion
Control
Lime
Lime
Lime
Lime
Lime
Lime
Disposal Process
POTW
POTW
Evaporation Pond +
non-Hazardous Landfill
Evaporation Pond +
non-Hazardous Landfill
Chemical Precipitation +
non-Hazardous Landfill
Chemical Precipitation +
non-Hazardous Landfill
non-Hazardous Landfill
non-Hazardous Landfill
non-Hazardous Landfill
POTW +
non-Hazardous Landfill
POTW +
non-Hazardous Landfill
POTW +
non-Hazardous Landfill
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Table 2-1 (Cont.)
Treatment Trains Evaluated for Arsenic Removal
Reverse Osmosis
Reverse Osmosis
Reverse Osmosis
Coagulation-Assisted
Microfiltration
Coagulation- Assisted
Microfiltration
Greensand Filtration
POE Activated Alumina
POU Reverse Osmosis
POU Activated Alumina
Regionalization
Alternate Source
Permanganate
Permanganate
Permanganate
Permanganate
Permanganate
Chlorine
Chlorine
Permanganate
Chlorine
NA
NA
Lime
Lime
Lime
Lime
Lime
Lime
NA
NA
Direct Discharge
POTW
Chemical Precipitation +
non-Hazardous Landfill
Mechanical dewatering -t-
non-Hazardous Landfill
non-Mechanical dewatering
+ non-Hazardous Landfill
POTW for Backwash
NA
NA
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Prior to implementation of any treatment strategy, a site-specific engineering study should
be performed to identify the most feasible technology application. The following factors should be
considered in any site-specific technical evaluation:
Quality and type of water source
Degree of contamination
Specific compound(s) present
Economies of scale and the economic stability of the community being served
Treatment, waste disposal, and land requirements
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3.0 COMPLIANCE TECHNOLOGY DESCRIPTIONS
3.1 INTRODUCTION
This section provides descriptions of the technologies listed in Section 2.0. The technologies
for arsenic removal, waste disposal, and pre-oxidation are discussed separately, rather than
describing each treatment train, to avoid repetition. The descriptions provided here are summarized
from Technologies and Costs for the Removal of Arsenic from Drinking Water (Draft) (EPA, 1999),
and Small Systems Byproducts Treatment and Disposal Cost Document (DPRA, 1993).
3.2 REMOVAL TECHNOLOGIES
The arsenic removal technologies evaluated in this Section are: enhanced lime softening;
enhanced coagulation/filtration; anion exchange; activated alumina; reverse osmosis; coagulation-
assisted microfiltration; and greensand filtration. In addition, point-of-entry and point-of-use
applications are evaluated for reverse osmosis (POU only) and activated alumina (both POE and
POU). Finally, regionalization and alternate source are evaluated as alternative strategies.
3.2.1 Enhanced Lime Softening
Hardness is predominantly caused by calcium and magnesium compounds in solution.
Lime softening (LS) removes this hardness by creating a shift in the carbonate equilibrium. The
addition of lime to water raises the pH. Bicarbonate is converted to carbonate as the pH
increases, and as a result, calcium is precipitated as calcium carbonate. Soda ash (sodium
carbonate) is added if insufficient bicarbonate is present hi the water to remove hardness to the
desired level. Softening for calcium removal is typically accomplished at a pH range of 9 to 9.5.
For magnesium removal, excess lime is added beyond the point of calcium carbonate
precipitation. Magnesium hydroxide precipitates at pH levels greater than 10.5. Neutralization
is required if the pH of the softened water is excessively high (above 9.5) for potable use. The
most common form of pH adjustment in softening plants is recarbonation with carbon dioxide.
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Softening is a successful technology for achieving greater than 90 percent As(V) removals.
Arsenic in the pentavalent arsenate form is more readily removed than the trivalent arsenite form.
Oxidation of As(III) to As(V) prior to LS treatment (i.e., pre-oxidation) will increase removal
efficiencies if As(m) is the predominant form. The optimum pH for As(V) removal by softening
is approximately 10.5 and the optimum pH of As(III) is approximately 11.0. Recent studies have
shown that As(V) removal is independent of initial concentration, while As(III) removal appears to
depend on initial concentration. Facilities precipitating only calcium carbonate observed lower
As(V) removals when compared to facilities precipitating calcium carbonate and magnesium and
ferric hydroxide. Addition of iron improves As(V) removal. Presence of sulfate and carbonate in
the raw water does not interfere with As(V) removal at pH 11. As(V) removal, however, is reduced
in the presence of carbonate at pH 10 to 10.5 and presence of orthophosphate at pH less than 12.
Considerable amounts of sludge are produced in a LS system and its disposal is expensive.
Large capacity systems may find it economical to install recalculation equipment to recover and
reuse the lime sludge, and thus reduce disposal problems. Construction of a new LS plant for the
removal of arsenic would not generally be recommended unless hardness must also be reduced.
The major design criteria and assumptions used by EPA (1999) to estimate costs for LS
treatment systems are summarized below:
Package plant for all small systems.
Lime dose, 250 mg/L.
Carbon dioxide (liquid), 35 mg/L for recarbonation.
Rapid mix, 1 minute.
Flocculation, 20 minutes.
Sedimentation, 1500 gpd/ft2 using circular tanks.
Dual media gravity filters, 5 gpm/ft2-
The major design criteria and assumptions used by EPA (1999) to estimate costs for systems
using enhanced LS treatment methods are summarized below.
An additional lime dosage of 50 mg/L.
Chemical feed system for increased lime dose.
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An additional carbon dioxide (liquid) dosage of 35 mg/L for recarbonation.
Chemical feed system for increase carbon dioxide dose.
3.2.2 Enhanced Coagulation/Filtration
Coagulation/filtration is a treatment process by which the physical or chemical properties of
dissolved colloidal or suspended matter are altered such that agglomeration is enhanced to an extent
that the resulting particles will settle out of solution by gravity or will be removed by filtration.
Coagulants change surface charge properties of solids to allow agglomeration and/or enmeshment
of particles into a flocculated precipitate. In either case, the final products are larger particles, or
floe, which more readily filter or settle under the influence of gravity.
The coagulation/filtration process has traditionally been used to remove solids from drinking
water supplies. However, the process is not restricted to the removal of particles. Coagulants render
some dissolved species (e.g., natural organic matter) insoluble and the metal hydroxide particles
produced by the addition of metal salt coagulants can adsorb other dissolved species. Major
components of a basic coagulation/filtration facility include chemical feed systems; mixing
equipment; basins for rapid mix, flocculation, and settling; filter media; sludge handling equipment;
and filter backwash facilities. Settling may not be necessary in situations where the influent particle
concentration is very low. Treatment plants without settling are known as direct filtration plants.
As(III) removal during coagulation with alum, ferric chloride, and ferric sulfate has been
shown to be less efficient than As(V) under comparable conditions (EPA, 1999). If As(III) is the
dominant species present, consideration should be given to pre-oxidation to convert As(HI) to As(V).
Enhanced coagulation treatment involves modifications to the existing coagulation process
such as increasing the coagulant dosage, reducing the pH, or both. Bench, pilot, and demonstration
scale studies to examine As(V) removals during enhanced coagulation (Cheng et al, 1994) indicate
that greater than 90 percent As(V) removal can be achieved under enhanced coagulation conditions.
These studies also indicate that enhanced coagulation using ferric salts is more effective for arsenic
removal than enhanced coagulation using alum.
The major design criteria and assumptions used to estimate costs for C/F treatment systems
are summarized below.
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Additional ferric chloride dose, 10 mg/L.
Additional feed system for increased ferric chloride dose.
Additional lime dose, 10 mg/L, for pH adjustment.
Additional feed system for increased lime dose.
3.2.3 Anion Exchange
Ion exchange (IX) is a physical/chemical process by which an ion on the solid phase is
exchanged for an ion in the feed water. This solid phase is typically a s^thetic resin which has been
chosen to preferentially adsorb the particular contaminant of concern. To accomplish this exchange
of ions, feed water is continuously passed through a bed of ion exchange resin beads in a downflow
or upflow mode until the resin is exhausted. Exhaustion occurs when all sites on the resin beads
have been filled by contaminant ions. At this point, the bed is regenerated by rinsing the IX column
with a regenerant, a concentrated solution of ions initially exchanged from the resin.
Important considerations in the applicability of the DC process for removal of a contaminant
include water quality parameters such as pH, competing ions, resin type, alkalinity, and influent
arsenic concentration. Other factors include the affinity of the resin for the contaminant, spent reg-
enerant and resin disposal requirements, secondary water quality eifects, and design operating
parameters.
Competition from background ions for IX sites can greatly affect the efficiency, as well as
the economics, of IX systems. The level of these background contaminants may determine the
applicability of IX at a particular site. Typically, strong-base anion exchange resins are used in
arsenic removal. Strong-base anion resins tend to be more effective over a larger range of pH than
weak-base resins. The order of exchange for most strong-base resins is given below, with the
adsorption preference being greatest for the constituents to the left.
HCrO4- > CrO42- > C1CV > SeO42-> SO42- > NO3' > Br > (HPO42-, HA.sO42-, SeO32-, CO32-) > CN'
> NO/ > Cl- > (HjPO4-, H2AsO4-, HCO3') > OH" > CH3COO- > F
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These resins have a relatively high affinity for arsenic in the arsenate form (HAsO42~),
however, previous studies have shown that high TDS and sulfate levels compete with arsenate and
can reduce removal efficiency (AWWA, 1990). In general, ion exchange for arsenic removal is only
applicable for low-TDS, low-sulfate source waters. Source waters with TDS levels above 500 mg/L
and sulfate levels above 25 mg/L are not recommended.
Chloride-form resins are often used in arsenic removal. Chloride ions are displaced from the
column as contaminants (arsenic) are sorbed onto the column. As a result, the potential exists for
increases in the chloride concentration of the product water. Increases in chlorides can greatly
increase the corrosivity of the product water.
Spent regenerant is produced during IX bed regeneration. Typically this spent regenerant
will have high concentrations of arsenic and other sorbed contaminants, and must be treated and/or
disposed of appropriately. Spent brine can be disposed of either directly to a surface water source,
or indirectly to a sanitary sewer, depending on contaminant levels. Spent regenerant, however, may
be reused many times. Regenerants do not need treatment prior to reuse, except to replenish the
chloride concentration to maintain a 1 M solution. Once the contaminant concentration becomes too
high in the regenerant, however, the spent solution must be treated and/or disposed.
Treatment of spent regenerant is accomplished in a number of ways. First, the spent
regenerant can be dewatered in some fashion. Common methods of dewatering IX residuals include
mechanical dewatering, drying beds, gravity thickeners, and lagoon dewatering. The solids
generated by these processes would need to be tested for toxicity and disposed of accordingly. If
determined to be non-toxic according to disposal regulations, the dried solids could be landfilled.
Waste liquid generated by these drying processes could be either directly discharged to a surface
water source or indirectly discharged to the sanitary sewer, depending on contaminant levels.
Spent brine can be treated by chemical precipitation. Clifford and Lin (1995) have shown
that arsenic levels can be substantially reduced using iron and aluminum coagulants as well as lime.
Much greater than the stoichiometric amounts (up to 20 times as much), however, are needed in
actual practice to reduce arsenic to low levels. In addition, pH adjustment may be necessary to
ensure optimum coagulation conditions.
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The major design criteria and assumptions used by EPA (1999) to estimate costs for anion
exchange treatment systems are summarized below.
Empty bed contact time (EBCT) of 2.5 minutes.
Regenerant dose of 15 lb/ft3 of resin.
Regenerant frequency of once per day.
Resin cost of $125/ft3.
Six-foot deep IX beds.
100 psi working pressure.
Nitrate =100 mg/L.
Sulfate = 80 mg/L.
Other anions =120 mg/L.
Nitrate capacity = 7 kilograins/ft3 resin.
Regenerant requirement = 15 Ib NaCl/ft3.
Regeneration time = 54 minutes.
Backwashing time =10 minutes.
Rinsing time = 24 minutes.
25% resin replacement per year.
3.2.4 Activated Alumina
Activated Alumina (AA) is a physical/chemical process by which ions in the feed water
are sorbed to the oxidized AA surface. AA is considered an adsorption process, although the
chemical reactions involved are actually an exchange of ions. Activated alumina is prepared
through dehydration of A1(OH)3 at high temperatures, and consists of amorphous and gamma
alumina oxide. AA is used hi packed beds to remove contaminants such as fluoride, arsenic,
selenium, silica, and natural organic matter (NOM). Feed water is continuously passed through
the bed to remove contaminants. The contaminant ions are exchanged with the surface hydroxides
on the alumina. When adsorption sites on the AA surface become filled, the bed must be
regenerated. Regeneration is accomplished through a sequence of rinsing with regenerant,
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flushing with water, and neutralizing with acid. The regenerant is a strong base, typically sodium
hydroxide; the neutralizer is a strong acid, typically sulfuric acid.
Many studies have shown that AA is an effective treatment technique for arsenic removal.
Factors such as pH, arsenic oxidation state, competing ions, empty bed contact time (EBCT), and
regeneration have significant effects on the removals achieved with AA. Other factors include
spent regenerant disposal, alumina disposal, and secondary water quality. Like nearly all other
treatment technologies, the oxidation state of arsenic plays a large role in its removal. As(V) is much
more easily adsorbed than As(III), and pre-oxidation of the water aids the removal process.
Like ion exchange processes, AA exhibits preference for some ions. AA, however, tends to
be specific for arsenic and is not as greatly affected by competing ions. As is indicated by the
general selectivity sequence shown below, AA preferentially adsorbs H2AsO4" [As(V)J over H3 AsQ
[As(III)]:
OH" > H2AsO4- > Si(OH)3O-> F> HSeO3- > TOC > SO42' > H3AsO3
Regeneration of AA beds is usually accomplished using a strong base solution, typically
concentrated NaOH. Relatively few BVs of regenerant are needed. After regeneration with strong
base, the AA medium must be neutralized using strong acid, typically two percent sulfuric acid.
Arsenic is more difficult to remove during regeneration than other ions such as fluoride. Because
of this, slightly higher base concentrations are used, typically four percent NaOH. Even at this
increased concentration, however, not all arsenic may be eluted. Regeneration also affects
successive bed life and efficiency. Bed life is shortened and adsorption efficiency is decreased by
regeneration.
Disposal of both spent regenerant and spent media is an important issue with arsenic
removal using AA. Spent regenerant can contain high levels of arsenic. Although little work has
been done in this area, it has been speculated that the spent AA media would pass toxicity tests and
could be landfilled. It is doubtful if spent regenerant could be discharge directly to a sanitary sewer.
Although the possibility of regenerant reuse exists, it may not be feasible for arsenic removal.
Direct reuse would probably not be possible due to the strong affinity of AA for arsenic. In other
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words, arsenic in the reused regenerant may actually be added to the column during regeneration.
Spent regenerant, however, may be treated prior to reuse. By precipitating the arsenic from the
regenerant, reuse may be possible assuming the regenerant solution was replenished and remained
concentrated enough to replenish the AA bed.
The design criteria and assumptions used to estimate costs for AA treatment systems are
summarized below. These criteria were taken from the Very Small Systems Best Available
Technology Cost Document (EPA 1993) to generate cost estimates presented by EPA (1999). The
design of any AA process must include consideration of the nature and concentration of the target
contaminant, characteristics of the raw water matrix, adsorption capacity of the alumina, and
regenerant usage. Because the characteristics of the target contaminant and raw water are site-
specific, pilot tests should be conducted prior to design and installation.
Empty bed contact time and regenerant usage are the primary design parameters for AA. For
purposes of estimating costs, the following assumptions are made regarding these parameters:
Very small systems will not provide pH adjustment, but will treat water at the ambient
pH.
Very small systems will not regenerate, but will dispose of the AA media when a bed is
exhausted.
EBCT of 15 minutes.
Sulfuric acid feed, 70 mg/L.
Caustic feed, 28.5 mg/L.
Regenerant dose of 0.3 Ib NaOH/kgal.
3.2.5 Reverse Osmosis
Reverse osmosis is the oldest membrane technology, traditionally used for the desalination
of brackish water and sea water. RO produces nearly pure water by maintaining a pressure gradient
across the membrane greater than the osmotic pressure of the feed water. Osmotic pressure becomes
great in RO systems compared to other membrane processes due to the concentration of salts on the
feed side of the membrane. The majority of the feed water passes through the membrane, however,
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the rest is discharged along with the rejected salts as a concentrated stream. Discharge concentrate
can be substantial, between 10 and 50 percent of the influent flow, depending on influent water
quality and membrane properties.
RO is an effective arsenic removal technology proven through several bench- and pilot-scale
studies. RO is very effective for removing dissolved constituents, including arsenic. Since the
arsenic found in groundwater is typically 80 to 90 percent dissolved, RO is a suitable technology for
arsenic removal from groundwater. Although RO can be an effective process for arsenic removal,
membrane type and operating conditions will affect removal and must be chosen appropriately. As
with other processes, RO removes As(V) to a greater degree than As(III), so maintaining oxidation
conditions may be important to the process.
RO performance is adversely affected by the presence of turbidity, iron, manganese, silica,
scale-producing compounds, and other constituents. RO requires extensive pretreatment for particle
removal and often pretreatment for dissolved constituents, even for high quality source waters. RO
has sometimes been used as a polishing step for already treated drinking water. Pretreatment can
make RO processes costly. Treated waters from RO systems typically have extremely high quality,
however, and blending of treated water and raw water can be used to produce a finished water of
acceptable quality. This may reduce cost to some extent.
The major design criteria and assumptions used by EPA (1999) to estimate costs for RO
treatment systems are summarized below.
Reverse osmosis units are single pass with an operating pressure of 400 to 500 psi.
The RO package unit consists of spiral wound or hollow fiber cellulose acetate,
polyamide, or thin film composite membranes.
Caustic is dosed at 100 mg/L; finished water pH is adjusted to 8.
3.2.6 Coagulation-Assisted Microfiltration
Arsenic is removed effectively during the coagulation process, as described in section 3.1.2.
Microfiltration is used as a membrane separation process to remove particulates, turbidity, and
microorganisms. In coagulation-assisted microfiltration technology, microfiltration is used similarly
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to a conventional gravity filter. The advantages of microfiltration over conventional filtration
include:
More effective microorganism barrier during coagulation process upsets.
Smaller floe sizes can be removed (smaller amounts of coagulants are required).
Increased total plant capacity.
Vickers et al. (1997) reported that microfiltration exhibited excellent arsenic removal
capability. Addition of a coagulant did not significantly affect the membrane cleaning interval,
although the solids level to the membrane system increased substantially. With an iron and
manganese removal system, it is critical that all of the iron and manganese be fully oxidized before
they reach the membrane to prevent fouling.
The major design criteria and assumptions used by EPA (1999) to estimate costs for
coagulation-assisted microfiltration treatment systems are summarized below.
Package plant for all small systems, filtration rate 5 gpm/ft2.
Ferric chloride dose, 25 mg/L.
Sodium hydroxide dose, 20 mg/L.
Rapid mix, 1 minute.
Flocculation, 20 minutes.
Sedimentation, 1000 gpd/ft2 in rectangular basins.
Standard microfilter specifications, provided by vendors.
3.2.7 Greensand Filtration
The active material in greensand is glauconite, a green, iron-rich, clay-like mineral which
exhibits ion exchange properties. Glauconite often occurs in nature as small pellets mixed with other
sand particles, causing the sand to appear green in color. To prepare the glauconite for use in a
greensand filtration process, it is mined, washed, screened, and chemically treated to coat the grains
with manganese dioxide, yielding durable, greenish-black, sand-sized particles. Impurities in water
are removed using greensand filtration through a combination of oxidation, ion exchange, and
particle entrapment. As water is passed through the greensand filter, soluble iron, manganese, and
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other metals are pulled from the solution through ion exchange to form insoluble oxides which are
later trapped by the filter medium. The oxidative nature of the manganese surface converts As(III)
to As(V) and As(V) is adsorbed at the surface. As a result of the transfer of electrons and adsorption
of As(V), reduced manganese (Mnll) is released from the surface. The major components of the
greensand filtration process include: (1) the greensand filtration medium, (2) backwash facilities,
and (3) potassium permanganate feed systems.
The effectiveness of greensand filtration for arsenic removal is dependent on the influent
water quality. Subramanian et al. (1997) showed a strong correlation between influent Fe (II)
concentration and arsenic percent removal. Removal increased from 41 percent to more than 80
percent as the Fe/As ratio was increased from 0 to 20 when treating a tap water with a spiked As(III)
concentration of 200 jag/L. The tap water contained 366 mg/L sulfate and 321 mg/L TDS; neither
constituent seemed to affect arsenic removal. The authors also point out that the influent Mn(IV)
concentration may play an important role. Divalent ions, such as calcium, can also compete with
arsenic for adsorption sites. Water quality would need to be carefully evaluated for applicability for
treatment using greensand. Other researchers have also reported substantial arsenic removal using
this technology, including arsenic removals of greater than 90 percent for treatment of groundwater
(Subramanian, et al., 1997).
As with other treatment media, greensand must be regenerated when its oxidative and
adsorptive capacity have been exhausted. Greensand filters are regenerated using a solution of
excess potassium permanganate (KMnO4). Like other treatment media, the regeneration frequency
will depend on the influent water quality in terms of constituents which will degrade the filter
capacity. Regenerant disposal for greensand filtration has not been addressed in previous research.
The major design criteria and assumptions used by EPA (1999) to estimate costs for
greensand filtration treatment systems are listed below.
Potassium permanganate feed, 10 mg/L.
The filter medium is contained in a ferrosand continuous regeneration filter tank
equipped with an underdrain.
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Filtration rate, 4 gpm/ft2.
Backwash is sufficient for 40 percent bed expansion.
3.2.8 Point-of-Entry and Point-of-Use Treatment
Centralized treatment is not always a feasible treatment option, for example, in areas where
each home has a private well or centralized treatment is cost prohibitive. In these instances, POE
and POU treatment options may be acceptable treatment alternatives. POE and POU systems offer
ease of installation, simplify operation and maintenance, and generally have lower capital costs.
These systems may also reduce engineering, legal, and other fees typically associated with
centralized treatment options. Use of POE and POU systems does not reduce the need for a well-
maintained water distribution system. In fact, increased monitoring may be necessary to ensure that
the treatment units are operating properly.
Home water treatment can consist of either whole-house or single faucet treatment. Whole-
house, or POE treatment is necessary when exposure to the contaminant by modes other than
consumption is a concern. POU treatment is preferred when treated water is needed only for
drinking and cooking purposes. POU treatment usually involves single-tap treatment.
The SDWA identifies POE and POU treatment units as potentially affordable technologies,
but stipulates that POE and POU treatment systems "... shall be owned, controlled and maintained
by the public water system, or by a person under contract with the public water system, to ensure
proper operation and compliance with the maximum contaminant level or treatment technique, and
equipped with mechanical warnings to ensure that customers are automatically notified of
operational problems."
Research has shown that POE and POU devices can be effective means of removing arsenic
from potable water (Fox and Sorg, 1987; Fox, 1989). Water systems with high influent arsenic
concentrations (i.e., greater than 1 mg/L) may have difficulty meeting MCLs much lower than the
10 to 20 //g/L level. As a result, influent arsenic concentration and other source water characteristics
must be considered when evaluating POE and POU devices for arsenic removal. To be effective
these devices should work with minimal attention and be relatively inexpensive for the user.
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Reverse osmosis, activated alumina, and ion exchange are three treatment techniques that
have been evaluated and shown to be effective POU and POE technologies. For this affordability
study, activated alumina and reverse osmosis have been selected for evaluation.
3.2.8.1
Activated alumina can be used in POE and POU units as packed beds to remove inorganic
contaminants from source water. In the AA process, contaminants are exchanged with the hydroxide
ions on the alumina surface. A description of AA in general can be found in Section 3.2.4.
Arsenic removal by AA has been shown to be most effective near pH of 5.5 to 6.0. Most
water systems will need some type of pH adjustment to accommodate this requirement. For POE
and POU systems this can be accomplished by treating the AA bed with dilute sulfuric acid. The
use of dilute sulfuric acid minimizes the possibility of unsafe treated water due to acidic pH, as well
as the likelihood that additional pH adjustment would be necessary to raise the pH after treatment.
The major design criteria and assumptions used by EPA ( 1 999) to estimate costs for POE and
POU treatment systems are listed below.
Average household - 3 individuals, 1 gallon each per day, 1,095 gallons per year.
Annual treatment - 1,095 gallons (POU), 109,500 gallons (POE).
Minimally skilled labor - $14.50 per hour (population less than 3,300 individuals).
Skilled labor - $28.00 per hour (population greater than 3,300 individuals).
Life of unit - 5 years (POU), 1 0 years (POE).
Duration of cost study - 1 0 years (therefore, two POU devices per household).
Cost of water meter and automatic shut-off valve included.
No shipping and handling costs required.
Volume discount schedule - retail for single unit, 10% discount for 10 or more units,
vendor retains 30% profit on more than 1 00 units.
Installation time - 1 hour unskilled labor (POU), 3 hours, skilled labor (POE).
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O&M costs include maintenance, replacement of pre-filters and resin cartridges,
laboratory sampling and analysis, and administrative costs.
3.2.8.2 Reyerse_Qsjn.o_sis
Reverse osmosis is a separation process that utilizes a membrane system to reject compounds
based upon molecular properties. Water molecules pass through the membrane, but most
contaminants, including arsenic, are rejected by the membrane. While a portion of the feed water
passes through the membrane, the rest is discharged with the rejected contaminants in a concentrated
stream. Membrane performance can be adversely affected by the presence of turbidity, iron,
manganese, scale-producing compounds and other contaminants. A more detailed discussion of the
RO removal process is presented in Section 3.2.5.
POU RO systems can be operated at both high (approximate^ 200 psig) and low (40 - 60
psig) pressures. High pressure RO devices typically operate at a product-to-reject water ratio of 1
to 3 (Fox, 1989), and require a booster pump to achieve the desired operating pressure. Low
pressure RO devices are less efficient and operate with a product-to-reject water ratio of about 1 to
10 (Fox, 1989). This can be a significant deterrent to RO treatment in dry regions or regions with
frequent water shortages.
Manufacturer and laboratory data suggest greater than 95 percent removal of arsenate by RO
systems, and slightly less (75 percent) removal of arsenite. Field studies indicate that greater than
50% removal is possible, but data are inconclusive much beyond those: levels. Accordingly, water
systems with high influent arsenic concentrations (i.e., greater than 1.0 mg/L) may want to consider
other POU treatment options.
Costs for POU RO systems were derived by EPA (1999) based upon the following criteria:
Average household - 3 individuals, 1 gallon each per day, 1,095 gallons per year.
Annual treatment -1,095 gallons.
Minimally skilled labor - $14.50 per hour (population less than 3,300 individuals).
Skilled labor - $28.00 per hour (population greater than 3,300 individuals).
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Life of unit - 5 years.
Duration of cost study -10 years (therefore, two POU devices per household).
Cost of water meter and automatic shut-off valve included.
No shipping and handling costs required.
Volume discount schedule - retail for single unit, 10% discount for 10 or more units,
15% discount on more than 100 units.
Installation time -1 hour unskilled labor.
» O&M costs include maintenance, replacement of pre-filters and membrane cartridges,
laboratory sampling and analysis, and administrative costs.
3.2.9 Regionalization
The term "regionalization" is used to define the process of purchasing and transporting water
from one community to another. In effect, regionalization expands the region served by a water
distribution system. Numerous economic, geographic, and operational factors can influence the
decision to implement regionalization, including: (1) the availability of water; (2) water quality; (3)
geography; and (4) economic factors.
Thriving communities that rapidly expand can easily outgrow their water source and find
themselves faced with water shortage problems. To alleviate this problem, communities may decide
to purchase water from other available sources in the region or neighboring communities. Water
quality also plays a role in the decision making process. If a community's source water is
contaminated, it may be cheaper for the community to purchase water from another rather that treat
its own water source. In some cases, contaminated water cannot be sufficiently treated and a
community may be faced with a choice to establish a new water source or to purchase water from
a neighboring community.
Economic factors affecting the decision for regionalization include design, materials,
construction, land, labor, and operational costs. Design costs include the engineering fees paid for
the design of the regionalization system. Material costs include piping, fittings, gaskets, bends,
valves, booster stations, pumps, and cathodic protection, among others. Construction costs include
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the costs associated with equipment rental and operation, excavation, backfilling, compaction, and
landscaping. Land costs include the land required for the placement of the piping and booster
stations, and the land required for the pipeline right-of-way. Labor costs include equipment
operators, laborers, superintendents, and site engineer. Operational costs include energy costs,
replacement parts, calibration, retrofitting, and operator costs.
The geographic location of a community will greatly affect the economic feasibility of
regionalization. The distance from the water source will affect construction and equipment costs,
and hilly or mountainous terrain can add significant design and consitruction costs. In addition,
obtaining right-of-way for pipelines and booster stations may be a significant factor in the decision
making process.
Additional factors include the lack of available water sources or change in the source
availability due to increased drawdown of groundwater, droughts affecting reservoirs, and other
man-made or natural changes to the water source. Increased per capita water use can increase the
demand for a larger water source or a new one, which also affects the decision process when
considering regionalization. Political issues associated with natural drainage boundaries, the desire
to avoid dependence on a single water source, and the reliability of the water source supply can also
affect the decision making for regionalization.
The following assumptions were made for the purpose of estimating regionalization costs:
A 92" wide by 120" deep trench was excavated for the placement of the conveyance
conduit. The width of the trench allows hand compaction around the pipe, the depth is
an average depth.
Type of soil was not taken into consideration, and no-rock excavation was assumed.
12" of fine gravel and sand were used to underlay the pipe.
3-48 magnesium anodes, at a spacing of 5 per mile, are assumed for the ductile iron pipe
cathodic protection.
The costs developed do not include costs associated with fittings, bends, gaskets, tees,
etc. These costs may vary greatly depending upon the topography of the site.
Air valves were assumed at 2 valves per mile. The location of air valves is also
dependent on the topography of the site; valves are usually located at the high points.
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One booster station with a 100 GPM, 150' Head, and a 10 HP centrifugal pump, is
assumed every two miles along the pipeline. The spacing and size of booster stations are
site dependent.
The cost of land purchase is not included.
No escalation factors were used.
The cost estimates do not include design costs, contractor profit and/or additional costs.
3.2.10 Alternate Source
If a community's source water is contaminated, it may be cheaper for the community to
develop an alternate source of water rather than treat the contaminated water. In some cases,
contaminated water cannot be sufficiently treated, and a community may be faced with a choice to
either establish a new water source, or to purchase water from a neighboring community.
Economic factors affecting the decision to develop an alternate water source include design,
materials, construction, land, labor, and operational costs. Design costs include the engineering fees
for the design of the added system. Material costs can include piping, fittings, gaskets, bends,
valves, booster stations, pumps, and cathodic protection, among others, depending on the source of
the new water supply. Construction costs include the costs associated with equipment rental and
operation; installation of ground water wells; excavation, backfilling, and compaction for piping;
and landscaping. Land costs may include the land required for the placement of a well, the piping
and booster stations, and the land required for the pipeline right-of-way. Labor costs can include
drillers, equipment operators, laborers, superintendents, and site engineer. Operational costs include
energy costs, replacement parts, calibration, retrofitting, and operator costs.
Additional factors include the lack of available water sources or a change in the source
availability due to increased drawdown of groundwater, droughts affecting reservoirs, and other
man-made or natural changes to the water source, whether surface or ground water. Increased per
capita water use can increase the demand for a larger water source or a new one, which also affects
the decision process when considering alternate sources. Political issues associated with natural
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drainage boundaries, the desire to avoid dependence on a single water source, and the reliability of
the water supply can also affect the decision-making process.
Because of the many variables associated with the development of an alternate source of
water, simplifying assumptions were applied to the cost estimates presented in this document. These
assumptions include:
The current water source is ground water, with the supply well on site.
The alternate source is a deeper, uncontaminated aquifer.
The alternate source is developed by installing a new well, or extending the depth of the
current well.
Developing the alternate source affects only capital costs; O&M costs remain the same.
Capital costs were established at a flat rate of $20,000 for each of the design flows
investigated.
3.3 RESIDUALS HANDLING AND DISPOSAL
Each of the treatment technologies presented in Section 3.1 will produce residuals, either
solid or liquid streams, containing elevated levels of arsenic. Costs for residuals handling and
disposal can be significant, and must be included in an evaluation of affordability of removal
technologies.
There are a number of factors which can influence residuals handling and disposal costs.
Capital costs include equipment, construction, installation, contractor overhead and profit,
administrative and legal fees, land, and other miscellaneous costs. The primary factor affecting
capital cost is the amount of residuals produced, which is dependent upon the design capacity of the
water treatment plant and the treatment process utilized (e.g., coagulation/filtration vs. lime
softening).
Operations and maintenance costs include labor, transportation, process materials and
chemicals, and maintenance. Many handling and disposal methods require extensive oversight
which can be a burden on small water systems. Generally, labor intensive technologies are more
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suitable to large water systems. Transportation can also play a significant role in determining
appropriate handling and disposal options. If off-site disposal requires extensive transportation,
alternative disposal methods should be evaluated. Complex handling and disposal methods usually
require more maintenance.
The amount of waste generated plays a significant role in determining the handling and
disposal method to be utilized. Many handling methods which are suitable for smaller systems are
impractical for larger systems because of the significant land requirements. For larger systems that
process residuals on-site (as opposed to direct or indirect discharge), mechanical methods are
typically used because of the land requirements.
The residuals handling and disposal methods evaluated here as part of the treatment processes
for arsenic removal include:
Landfill disposal.
Publicly-owned treatment works (POTW) disposal.
Evaporation Ponds.
Chemical precipitation.
Mechanical dewatering.
Non-mechanical dewatering.
3.3.1 Landfill Disposal
Two forms of sanitary landfill are commonly used for disposal of water treatment
byproducts: monofills and commercial nonhazardous waste landfills (DPRA, 1993). Monofills only
accept one type of waste, for example, fly ash or water treatment sludges. Commercial
nonhazardous waste landfills accept a variety of commercial and industrial wastes.
Sanitary landfills are regulated by both state and federal regulations. States have guidelines
on what types of waste can be landfilled, and determine construction and operation criteria. In many
cases, state requirements are more stringent than the federal regulations promulgated under the
Resource Conservation and Recovery Act (RCRA). The federal requirements include restrictions
on location, operation and design criteria, ground water monitoring requirements, corrective action
requirements, closure and post-closure requirements, and financial assurance.
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Landfill disposal requires that residuals be in a solid form and contain no free liquids.
Sanitary landfill disposal also requires that sludges meet specific criteria that determine if a waste
is hazardous. 40 CFR 261 establishes four characteristics of hazardous waste: flammability,
corrosiviry, reactivity, and toxicity. A waste must meet only one of the criteria to be considered
hazardous. With treatment residuals containing arsenic, toxicity is the primary characteristic of
concern.
EPA has established an analytical method, the Toxicity Characteristic Leaching Procedure
(TCLP), to measure the toxicity of a waste. The current TCLP limit for arsenic is 5 mg/L, which
is 100 times the current MCL of 50 /zg/L. If the MCL is lowered in the future, the TCLP value will
be lowered accordingly. For example, if the MCL were lowered to 20 Mg/L or 2 ju-g/L, the TCLP
would be lowered to 2.0 mg/L or 200 ,ug/L, respectively. As a result, water treatment residuals
containing arsenic may meet current sanitary landfill disposal criteria, but may not under a future
regulatory framework.
Many water treatment facilities currently dispose of their waste in commercial or public-
owned landfills. In some parts of the country, decreasing landfill availability, rising costs, and
increasing regulations are making landfill disposal more expensive. As a result, the benefits of
monofills are being discussed within the industry. Costs associated with development of mono fills
is generally less than that of a sanitary landfill. Monofills control the type of waste disposed more
strictly and limit the potential future liabilities.
The following assumptions were made for the purpose of estimating landfill disposal costs:
A commercial nonhazardous waste landfill is used for sludge disposal.
Transportation distance is less than 50 miles.
There is no economy of scale for large waste volumes.
All wastes pass the Paint Filter Liquids Test.
The waste does not exhibit the characteristics of ignitability, corrosivity, reactivity, or
toxicity.
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3.3.2 Publicly-Owned Treatment Works
In some cases, water treatment process sludges, slurries, and brines may be discharged to a
POTW. This most often occurs when the treatment plant and POTW are under the same
management authority.
Discharge to a POTW is a commonly used method of disposal for filter backwash and brine
waste streams. Coagulation/filtration and lime softening sludges have also been successfully
disposed of in this manner. However, the POTW must be able to handle the increased hydraulic and
solids loading. The capacity of the sewer system must also be considered when selecting indirect
discharge as a disposal option.
The residuals generated from an arsenic treatment process will be classified as an industrial
waste since it contains contaminants, namely arsenic, which may impact the POTW. As a result,
discharge to a POTW is only acceptable when arsenic concentrations fall within the established
Technically Based Local Limits (TBLL) of the current Industrial Pretreatment Program (AWWARF,
1998). The Industrial Pretreatment Program serves to prevent NPDES violations, as well as
unacceptable accumulation of contaminants in POTW sludges and biosolids. TBLLs are
individually determined for each POTW, and take into account background levels of contamination
in the municipal wastewater.
The primary cost associated with indirect discharge is that of the piping. Accommodations
must also be made for washout ports to prevent clogging because of sedimentation in pipelines.
Valving is necessary to control waste flow in the event of pipe bursts, and pipe must be laid at a
sufficient depth to prevent freezing in winter months. Additional costs associated with indirect
discharge may include lift stations, additional piping for access to the sewer system, or other
surcharges to accommodate the increased demands on the POTW. The following design
assumptions were made for the purpose of estimating the costs of discharge to a POTW:
The byproduct stream flows by gravity or under pressure from the treatment process via
PVC piping to the sewer line.
Two-inch minimum diameter pipe is used to prevent clogging. Schedule 40 PVC pipe
is used.
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Byproduct flow rates range from 100 to 100,000,000 gallons per day, depending on the
water treatment technology.
The sewer line connection is 500 feet from the water treatment system.
Holding tanks and lagoons are not required for small water treatment systems.
Costs are for discharge of brines and slurries, and do not include total suspended solids
(TSS) or biological oxygen demand (BOD) surcharges.
3.3.3 Evaporation Ponds
Evaporation ponds and drying beds are non-mechanical dewEitering technologies wherein
favorable climatic conditions are used to dewater waste brines generated by treatment processes such
as reverse osmosis and ion exchange. Such processes produce large volumes of high total dissolved
solids (TDS) waste streams and make mechanical dewatering processes, such as filter presses,
impractical. Depending upon the solids concentration of the brine waste stream, intermittent
removal of solids may be required. For brines with a TDS content ranging from 15,000 to 35,000
mg/L, solids will accumulate in the pond at a rate of 1A to 1 Vz inches per year. When the depth of
the solids reaches a predetermined level, flow to the pond is halted and evaporation continues until
the solids concentration is suitable for disposal.
Evaporation is an extremely land intensive handling option requiring shallow basins with
large surface areas. This can be an important consideration hi densely populated regions. Reverse
osmosis produces a very large volume reject stream which increases the land requirement and
construction costs. As a result, evaporation ponds may not be suitable for large water systems
utilizing reverse osmosis. Evaporation ponds and drying beds have few operations and maintenance
requirements, but are only feasible in regions with high temperatures, low humidity, and low
precipitation. Waste streams with low TDS concentrations can allow a pond to operate for several
years before solids accumulation warrants removal.
The following assumptions were made for the purpose of estimating evaporation pond costs:
The influent solids concentration ranges from 1.5 to 3.5 percent by weight.
Waste brines flow from the treatment plant to the evaporation pond by gravity via two-
inch diameter PVC piping. The total distance is less than 7,500 feet.
3-22
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Waste brine flow rates are greater than 200 gallons per day.
The pond is designed for a geographic region with a net annual evaporation rate of at
least 45 inches per year.
The pond has no outlet.
The ponds are sized with sufficient surface area to evaporate the average daily flow.
Pond depth is two feet to provide solids storage volume and to accommodate peak flows.
The pond is constructed with a synthetic membrane liner and a geotextile support fabric;
one foot of sand is placed on top of the liner.
Soils cut from the excavation of the basin are used to construct the berm.
The earthen berm has 2.5-to-l side slopes and two feet of free board.
3.3.4 Chemical Precipitation
Chemical precipitation is applicable to aqueous byproduct streams such as ion exchange
backwash and reverse osmosis brines. It is frequently used to remove dissolved metals, including
arsenic, from aqueous solutions. The precipitation process involves adding a precipitant, such as
hydroxide ions, to ion exchange or reverse osmosis brines hi a stirred reactor vessel. Lime,
quicklime, soda ash, and caustic soda are commonly used as sources of hydroxide ions. The
dissolved metals are converted to an insoluble form by a chemical reaction between the soluble metal
ions and the precipitant.
The resulting suspended solids are separated from the aqueous phase in a clarifier.
Flocculation with or without a chemical coagulant or settling aid may be used to enhance the
removal of suspended solids. The supernatant from the clarifier is either discharged to the sanitary
sewer, to surface water, or to the the head of the treatment plant, depending on the pH. Prior to
disposal, the clarifier sludge may require additional dewatering by mechanical or non-mechanical
means. The following assumptions were made for the purpose of estimating the costs associated
with chemical precipitation:
The chemical precipitation system consists of mixing and holding tanks for the lime
solution, a precipitation tank, a clarifier, agitators, and pumps.
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The precipitation tank has a H-hour retention time and a 5 percent overdesign.
The clarifier (settling tank) has a 1- to 2-hour retention time.
Waste brines flow to the treatment system under pressure from the ion exchange or
reverse osmosis system.
The chemical precipitation equipment is located in the water treatment building.
The sludge volumes generated by chemical precipitation are 5 and 2 percent of the
influent volumes for reverse osmosis and ion exchange brines, respectively.
3.3.5 Mechanical Dewatering
Mechanical dewatering processes include centrifuges, vacuum-assisted dewatering beds, belt
filter presses, and plate and frame filter presses. Such processes generally have high capital and high
O&M costs compared to similar capacity non-mechanical dewatering processes. Due to their high
costs, such processes are generally not suitable for very small water systems.
Filter presses have been used in industrial processes for years, and their use has been
increasing in the water treatment industry over the past several years. These devices have been
successfully applied to both lime and alum sludges. Filter presses require little land, have high
capital costs, and are labor intensive.
Centrifuges have also been used in the water industry for years. They are capable of
producing alum sludges with final solids concentrations of 15 to 30 percent and lime sludges with
65 to 70 percent total solids, based upon an influent solids concentration of 1 to 10 percent.
Centrifugation is a continuous process requiring minimal time (8 to 12 minutes) to achieve the
optimal sludge solids concentration. Centrifuges have low land requirements and high capital costs.
They are more labor intensive than non-mechanical alternatives, but less intensive than filter presses.
The following assumptions were made for the purpose of estimaiting mechanical dewatering
costs:
Pressure filter presses are effective for sludge flow rates greater than 100 gallons per day.
Stainless steel filter presses with paper filter media are used for flow rates less than 500
gallons per day.
3-24
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Sludge flows by gravity to a polymer feed system.
The polymer feed system consists of a polymer storage tank, a polymer pump, a
polymer/sludge contact tank, and a 20- to 30-minute holding tank.
A positive displacement pump delivers sludge to the filter press.
The filter press operates on a batch basis.
Filtrate collects in a filtrate holding tank before being pumped to the head of the
treatment plant.
Filter cake collects in a small, wheeled container, which is emptied into a larger-solids
bin, as necessary.
Accumulated solids require disposal on a periodic basis.
The dewatered sludge volume is 0.03 and 8 percent of the initial volume for lime and
alum sludges, respectively.
3.3.6 Non-Mechanical Dewatering
Non-mechanical dewatering of sludges and slurries is performed in sand drying beds, storage
lagoons, and permanent lagoons. Non-mechanical dewatering processes are characterized by their
simplicity to. operate and maintain. In sand drying beds and storage lagoons, dewatered sludge is
removed for disposal via land application or in a landfill. A permanent lagoon dewaters the sludge
and is the final disposal site for the sludge.
A sand drying bed uses drainage, decanting, and evaporation for dewatering sludges. The
technology involves spreading an even layer of thickened sludge over a draining sand bed. Free
water in the sludge drains through the sand to the underdrains, or forms a supernatant layer that is
decanted. Most gravity and decant drainage occurs in the first few days after application. After this
time, evaporation is the primary dewatering process, and the sludge remains on the drying bed until
the desired solids concentration is achieved.
Sludge removal and disposal costs are a large percentage of the total operation and
maintenance costs for drying beds. Sludge removal costs are directly related to the number of sludge
3-25
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applications per drying bed per year. Less frequent, thicker sludge applications result in a thicker
sludge cake that has lower unit costs for removal, but may require more drying bed area. Individual
treatment plants must determine their most cost effective drying times and disposal frequencies.
The following assumptions were made for the purpose of estimating costs associated with
non-mechanical dewatering:
Sludges flow to the lagoons or tanks via 500 feet of 2- to 6-inch diameter PVC piping
buried 4 feet below the ground surface.
Sludge is concentrated to 3 percent solids by weight in a lagoon or tank through
decanting and evaporation; the sludge volume is reduced by 67 percent.
The lagoons are constructed with a synthetic membrane liiner and a geotextile support
fabric.
An 18-inch layer of sludge containing 3 percent solids is applied up to 12 times per year
to each sand bed.
The sludge pump and the drying bed piping are sized to deliver sludge to the drying bed
from the lagoon in one to two hours. Drying beds are located 100 feet from the lagoon.
Drying beds are sized to hold 33 percent of the initial sludge volume applied to the bed
in an 18-inch layer. Increased sizing is used to offset slower drying times in bad weather.
Underdrains consisting of 2- to 6-inch diameter PVC piping collect filtrate.
Drying beds are constructed of reinforced concrete with a 6--inch bottom slab and 8-inch
walls. The bed contains 18 inches of sand. The underdrain piping rests in 6 inches of
gravel beneath the sand.
The concentration of the final solid is 20 percent by weight. Five percent of the initial
sludge (0.7 cubic feet of solids per 100 gallons of initial sludge volume) requires final
disposal.
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3.4 PRE-OXIDATION PROCESSES
Inorganic arsenic occurs in two primary valence states, arsenite (As III) and arsenate (As V).
Surface waters more typically contain As(V), while As(III) is the dominant species found in ground
waters. Each of the treatment technologies presented in this document remove As(V) more readily
than As(III), and pre-oxidation may be necessary, depending upon source water conditions, to
improve arsenic removal.
Potassium permanganate addition and chlorination are two oxidation technologies that have
been evaluated and deemed effective for the conversion of arsenite to arsenate. Although
chlorination is less expensive than potassium permanganate, chlorine addition may cause the
formation of disinfection by-products (DBFs) in source waters with high total organic carbon (TOC)
concentrations, and may cause fouling in some membrane processes. Source water characteristics
and down-stream processes should be considered when selecting pre-oxidation technologies.
Additional oxidation technologies, such as ozonation and hydrogen peroxide, may be effective, but
need further evaluation.
3.4.1 Chlorination
Chlorination is a low-cost pre-oxidation method that can be successfully used with many
arsenic removal technologies, especially those that are not membrane processes. Capital and O&M
costs were developed for chlorination systems in the Technologies and Costs for the Removal of
Arsenic from Drinking Water (Draft) (EPA, 1999). The design assumptions used for calculating
costs of chlorination include the following:
Chlorination is accomplished with a hypochlorite feed system capable of providing
dosages to 10 mg/L as chlorine. The system is equipped with a 150 gallon storage tank
and utilizes a 15 percent sodium hypochlorite feed stock.
Labor requirements for O&M costs are assumed to be 8 hours per week.
Cylinder feed chlorination system is assumed.
3-27
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Some systems currently using chlorine for disinfection may be able to modify existing
chlorine feed systems to utilize chlorine as a preoxidant with significant capital cost savings.
3.4.2 Potassium Permanganate
Potassium permanganate may be used as a pre-oxidant when ehlorination is not practical.
Costs for permanganate addition are taken from Technologies and Costs for the Removal of Arsenic
from Drinking Water (Draft) (EPA, 1999). The design assumptions used for calculating costs
include the following:
The potassium permanganate feed system is equipped with a metering pump, solution
tank with mixer, pipes and valves, and instrumentation and controls. The system utilizes
a 3 percent potassium permanganate solution.
Labor requirements for O&M costs are assumed to be 8 hours per week.
For small system potassium permanganate addition, a dry chemical feed system capable
of 1,000 pounds per day is used.
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4.0 NATIONAL-LEVEL AFFORDABILITY DETERMINATION
4.1 DISTINCTIONS BETWEEN NATIONAL- AND SYSTEM-LEVEL
AFFORDABILITY
Section 1412(b)(15)(C) of the SDWA requires EPA to list any assumptions used in
determining affordability, taking into consideration the number of persons served by systems when
variance technologies are listed. The costs detailed in this chapter were compared to the
affordability criteria set forth in the National-Level Affordability Criteria Under the 1996
Amendments to the Safe Drinking Water Act, (EPA, 1998a).
Although the SDWA does not specifically address the ability of a system to afford
compliance technologies for existing regulations, the EPA's interpretation of the statute is that
affordability is a key criterion for evaluating technologies for both existing and future regulations.
The national-level affordability criteria used to make affordable variance technology determinations
are different from the system-level criteria used by states to determine if a system should receive a
small system variance. Technologies determined to be unaffordable for a particular small system
size category under the national-level affordability criteria may still be affordable for a specific
system within the size category, hi such a case, the system may install the technology. Conversely,
if a financially disadvantaged small water system that is out of compliance with a NPDWR cannot
afford any of the compliance technologies determined to be affordable under the national-level
affordability criteria, that system could apply to the state for an exemption. However, new
exemptions will only be available for regulations issued or revised after August 6, 1998. Those
small systems with existing exemptions for rules in effect on August 6,1998 may continue to get
renewals of their exemptions until the exemption period expires. A small system will be allowed
no more than 9 years after the Section 1412 compliance date to meet the applicable MCL or
treatment technique, even if the exemption was issued prior to the 1996 SDWA Amendments.
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4.2 ROLE OF NATIONAL-LEVEL AFFORD ABILITY CRITERIA
National-level affordability criteria help define the range of options available to a small
system out of compliance with a NPDWR. The available options are:
Install a technology to comply with the NPDWR.
Receive an exemption, then install a technology to comply with the NPDWR.
Obtain a small system variance (if option is available).
The compliance technology list is intended to provide small systems with information
concerning the types of technologies that can be used to comply with a given NPDWR.
The primary role of the national-level affordability criteria is to determine whether a system
of a given size/source water quality combination should proceed down the compliance or variance
technology pathway. A secondary function is to define the technologies within the compliance or
variance technology pathway as demonstrated in the compliance technology tables in Small System
Compliance Technology List for the Non-Microbial Contaminants (EPA, 1998b). As mentioned in
Chapter 2, a number of technologies not included on this list of compliance technologies were
evaluated in the technologies and costs document for arsenic removal (EPA, 1999). To provide the
maximum amount of information to small systems, all technologies for which cost information was
available were evaluated against the national-level affordability criterion.
4.3 UNIT OF MEASURE FOR THE NATIONAL-LEVEL AFFORDABBLITY CRITERIA
Community water systems (CWS) can finance additional costs by increasing the rates offered
to customers. The typical customer base in the smallest system size category is almost exclusively
residential. The lack of non-residential customers reduces the ability of these systems to spread the
cost of SDWA compliance beyond the household level. The two larger size categories of small
systems have a greater percentage of non-residential customers than the smallest size category.
However, residential water bills still account for the majority of revenues received by such systems.
Therefore, the national-level affordability criteria for CWSs are based on the ability of households
4-2
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to shoulder the additional costs of installing a technology to meet a NPDWR. Further information
on the selection of the household as the most sensitive user for cost increases can be found in EPA's
national-level affordability analysis (EPA, 1998a).
Since household cost is used as the basis for determining treatment affordability, the selected
approach developed to assess user burden associated with CWSs involves measuring the increase
to annual household water bills resulting from the installation of a particular treatment technology.
To determine if there are any affordable compliance technologies, the national-level affordability
criteria are compared against the cost estimates for treatment technologies applicable for controlling
a given contaminant. If there are no affordable compliance technologies, then variance technologies
would become an option.
While the increased cost of production due to the installation of additional treatment
technology is measured in dollars per thousand gallons ($/Kgal), annual household water
consumption, which is needed to convert the treatment technology costs into the increase in annual
household water bills, is measured in thousands of gallons per year (Kgal/year). To make the
comparison between household impacts and treatment costs, the increased cost of production was
multiplied by annual household consumption to compute the annual increase to household water bills
expressed in dollars per household per year ($/HH/year).
The annual water consumption rates derived from data in the 1995 Community Water System
Survey (CWSS) are contained in Table 4-1. Only the median values for water consumption are
included for each size category. These consumption rates are considerably lower than the 100,000
gal/HH/year used in the development of regulations prior to 1996. The pre-1996 consumption rate
was based on large systems and extrapolated across all system size categories. The new baselines
for annual household water consumption were derived from data in the 1995 CWSS, and are based
on specific system size data. For this analysis, the annual baseline household consumption estimates
were multiplied by 1.15 to account for lost water due to leaks.
4-3
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Table 4-1
Residential Consumption at Small Water Systems
System Size Category
(Population Served)
25 - 500
501 - 3,300
3,301 - 10,000
Annual
Consumption
(kgal/connection)
72
74
77
Adjusted
Consumption
(kgal/connection)
83
85
89
4.4 DERIVATION OF THE NATIONAL-LEVEL AFFORDABILITY CRITERIA
A summary of the methodology used to determine the national-level affordability criteria is
provided below. EPA has chosen to express the water system financial and operational
characteristics using median values as a measure of central tendency. EPA believes that national-
level affordability criteria should describe the characteristics of typical systems and should not
address extreme situations where costs might be extremely low or excessively burdensome.
The national-level affordability criteria has three major components: current annual water
bills, median household income, and the affordability threshold. Baseline annual household water
cost data includes existing water quality (i.e., treatment and monitoring), water production (i.e.,
labor and energy for supply pump operation), and water distribution costs, including infrastructure
repair (e.g., mains and service lines) and administrative costs (e.g., customer billing and meter
checking). The baseline for annual water bills was derived from the CWSS, while baseline annual
water bills are based on average system revenues per household per year. The median household
income data were derived by linking CWSS data with data in the 1990 Census using zip codes. The
Census income data were converted from 1990 dollars to 1995 dollars using the Consumer Price
Index (CPI) to facilitate comparison with the CWSS data. By linking the CWSS and Census, a
median household income per system size category was created. Trie affordability threshold was
determined by comparing the baseline water costs with other household expenditures.
4-4
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For the majority of small systems, the bulk of current annual household water costs is related
to water production and distribution. Furthermore, most ground water systems do not have extensive
treatment trains. Because CWSS data were collected in 1995, treatment costs for many regulated
contaminants may already be accounted for in the baseline. The Consumer Expenditure Survey
(CES) data were used to derive estimates of the amount spent per household on a variety of goods
and services. In preparing the national-level affordability analysis, EPA (1998a) selected a subset
of household expenditures described as comparable expenditures. The subset was selected to
represent vital expenses and primary uses of disposable income. In the CES data, there is a category
for utilities, fuels, and other public services, including water. Expenditures for natural gas,
electricity, fuel oils and other fuels are also included in this category. These three utilities are
competitors for power and heating, so households that do not purchase one or more of these utilities
would bias the individual percentages. Power and heating utilities were combined into one category
called energy and fuels. The subset of expenditures also included other utilities and miscellaneous
expenses.
This information was used to develop a range, based on the cost of water service as a
percentage of median household income (MHI), in which treatment technologies are deemed
affordable. The upper and lower boundaries of the affordability range were guided by the cost of
other household expenditures as a percentage of MHI. The affordability threshold was determined
by comparing the cost of public water supply for households with other household expenditures and
risk-averting behaviors. This consumer expenditure data provided a basis for establishing an
affordability threshold by comparing baseline household water costs to MHI to determine the
financial impact of increased water costs on households. The subset of comparable expenditures
from the CES data is contained in Table 4-2.
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Table 4-2
Summary of Select Consumer Expenditures for All Consumer Units (1995$)
Item
Housing
Transportation
Food
Energy and Fuels
Telephone
Water and other Public Services
Entertainment <
Alcohol and Tobacco .
% of Median Household Income (before taxes)
28.3%
16.3%
12.2%
3.3%
1.9%
0.7%
4.4%
1.5%
Using comparable expenditures as a guide, the lower bound of the affordability range was
established as 1.5 percent of median household income, while the upper bound was established as
3 percent. The lower bound was based on the expenditures for alcohol and tobacco. Rounding down
the percentage spent on energy and fuels served as the upper bound of the affordability range. When
presented with an initial range of affordability thresholds extending from 1.5 percent to 3 percent
of MHI, stakeholders, in general, did not express a strong opinion regarding how to select a specific
threshold within the range. Subsequently, EPA selected 2.5 percent as the affordability threshold.
To determine the maximum allowable increase that can be imposed by treatment and still be
considered affordable, current annual household water bills were subtracted from the affordability
threshold. This difference was compared with treatment costs for each evaluated technology to make
a national-level affordable determination. This difference is called the available expenditure margin.
Table 4-3 details the national-level of affordability criteria established by EPA (1998). For purposes
of this analysis, the values for MHI and median household water cost were escalated to 1999 dollars
using the CPI.
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Table 4-3
National Level Affordability Criteria
Cost Basis 1995 Dollars (Cost Basis 1999 Dollars)
System Size
Population
Served
25-500
501-3,300
3,301-10,000
Baseline
Median MHI
30,785 (33,248)
27,058 (29,223)
27,641 (29,852)
Median Water
Bills ($/HH/yr)
211(228)
184(199)
181 (195)
Water Bills
(%Mffl)
0.69 (0.69)
0.68 (0.68)
0.65 (0.65)
Affordability
Threshold
(2.5% of MHI)
770 (831)
676 (730)
691 (746)
Available
Expenditure
Margin
($/HH/yr.
Increase)
559 (603)
492(531)
510(551)
As mentioned above, the affordability threshold was set by EPA at 2.5 percent of MHI for
all existing and future regulations. The baseline for annual water bills will increase as treatment is
installed to comply with regulations and meet the current backlog of infrastructure needs. By
conducting the CWSS every five years, EPA will be able to track increases in water bills due to
treatment or infrastructure repair. In the interim, EPA will adjust the baseline water expenditure
estimates to incorporate the projected impact of regulations. Furthermore, the CPI shows water
prices increasing at a faster rate than all items over the last ten years (EPA, 1998a). This implies that
water prices should increase faster than MHI, decreasing the available expenditure margin over time
(see Table 4-3).
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4.5 DETERMINATION OF HOUSEHOLD AFFORDABILITY
Table 4-4 details the affordability assessment for the application of treatment alternatives
discussed in this document for control of arsenic contamination. The annual total costs reported
represent the summation of annual total cost (in dollars) associated with a compliance technology
upgrade at 6.25 percent interest and annual baseline expenditures (EPA, 1998a). In these tables, the
annual cost associated with the upgrade is the product of yearly cost per unit treated using a given
technology, times the average yearly consumption of residential customers. The annual baseline
water cost discussed above was developed by EPA (1998c). Annual total cost is the sum of the
baseline cost and the additional cost due to the new treatment technolo^. Size-specific MHI values
were also obtained from EPA (1998c). Finally, the annual total cost as a percentage of income is
the ratio of the new cost to income.
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Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Annual Cost
assoc. w/upgrade
($/HH)
Annual Baseline
Median Water
Cost($/HH)
Annual Total Cost
($/HH)
MHI ($)
Annual Total Cost
as a % of MHI
Population Sizes Ranging from 25 to 500
Enhanced Lime Softening
+ Pre-Oxidation
Enhanced Coagulation/Filtration
+ Pre-Oxidation
Anion Exchange (25 mg/l SO.,)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l SO4)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l S04)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7,000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16.500 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16,500 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Reverse Osmosis
+ Direct Discharge Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
56
50 .
187
298
385
495
335
446
501
334
262
513
345
273
963
228
284
278
415
526
613
723
563
674
729
562
490
741
573
501
1191
33,248
0.86
0.84
1.25
1.58
1.84
2.18
1.69
2.03
2.19
1.69
1.48
2.23
1.72
1.51
3.58
4-9
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Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Reverse Osmosis
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Reverse Osmosis
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
+ Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
+ Non-Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Greensand Filtration
+ POTW for Backwash Stream
POE Activated Alumina
+ Corrosion Control
+ Pre-Oxidation
POU Reverse Osmosis
+ Pre-Oxidation
POU Activated Alumina
+ Pre-Oxidation
Regionalization
Alternate Source
Annual Cost
assoc. w/upgrade
($/HH)
1036
1206
1163
1134
156
421
330
334
377
26
Annual Baseline
Median Water
Cost ($/HH)
228
Annual Totil Cost
($/HH)
1264
1434
1391
1362
384
649
558
562
605
254
MHI ($)
33,248
Annual Total Cost
as a % of MHI
3.80
4.31
4.18
4.10
1.15
1.95
1.68
1.69
1.82
0.77
4-10
-------
Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Annual Cost
assoc. w/upgrade
(S/HH)
Annual Baseline
Median Water
Cost($/HH)
Annual Total Cost
(S/HH)
MHI ($)
Annual Total Cost
as a % of MHI
Population Sizes Ranging from 501 to 3,300
Enhanced Lime Softening
+ Pre-Oxidation
Enhanced Coagulation/Filtration
+ Pre-Oxidation
Anion Exchange (25 mg/l SO4)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l S04)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l S04)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S0«)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7.000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16,500 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16,500 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Reverse Osmosis
+ Direct Discharge Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
17
12
198
218
309
328
216
236
404
240
170
407
243
172
328
199
216
211
397
417
508
527
415
435
603
439
369
606
442
371
527
29,223
0.74
0.72
1.36
1.43
1.74
1.80
1.42
1.49
2.06
1.50
1.26
2.07
1.51
1.27
1.81
4-11
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Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Reverse Osmosis
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Reverse Osmosis
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
* Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
+ Non-Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Greensand Filtration
+ POTW for Backwash Stream
POE Activated Alumina
+ Corrosion Control
+ Pre-Oxidation
POU Reverse Osmosis
+ Pre-Oxidation
POU Activated Alumina
+ Pre-Oxidation
Regionalization
Alternate Source
Annual Cost
assoc. w/upgrade
($/HH)
404
414
288
337
60
343
276
271
34
3
Annual Baseline
Median Water
Cost($/HH)
199
Annual Total Cost
($/HH)
603
613
487
536
259
542
475
470
233
202
MHI ($)
29,223
Annual Total Cost
as a % of MHI
2.06
2.10
1.67
1.83
0.89
1.85
1.62
1.61
0.80
0.69
4-12
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Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Annual Cost
assoc. w/upgrade
(S/HH)
Annual Baseline
Median Water
Cost($/HH)
Annual Total Cost
($/HH)
MHI ($)
Annual Total Cost
as a % of MHI
Population Sizes Ranging from 3,301 to 10,000
Enhanced Lime Softening
+ Pre-Oxidation
Enhanced Coagulation/Filtration
+ Pre-Oxidation
Anion Exchange (25 mg/l SO4)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l S04)
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l SO4)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l SO4)
+ Evaporation Pond
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (25 mg/l SO,)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Anion Exchange (150 mg/l SO4)
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7,000 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16,500 BV)
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (3,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (7,000 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Activated Alumina (16,500 BV)
+ POTW Waste Disposal
+ Non-hazardous Landfill
+ Pre-Oxidation
Reverse Osmosis
+ Direct Discharge Waste Disposal
* Corrosion Control
+ Pre-Oxidation
15
12 .
90
99
182
190
101
111
394
228
157
397
228
158
278
195
210
207
285
294
377
385
296
306
589
423
352
592
423
353
473
29,852
0.70
0.69
0.96
0.99
1.26
1.29
0.99
1.02
1.97
1.42
1.18
1.98
1.42
1.18
1.58
4-13
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Table 4-4
Affordability Assessment of Technologies Examined for Removal of Arsenic Contamination
Treatment Train
Reverse Osmosis
+ POTW Waste Disposal
+ Corrosion Control
+ Pre-Oxidation
Reverse Osmosis
+ Chemical Precipitation
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
+ Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Coagulation-Assisted Microfiltration
+ Non-Mechanical Dewatering
+ Non-hazardous Landfill
+ Corrosion Control
+ Pre-Oxidation
Greensand Filtration
+ POTW for Backwash Stream
POE Activated Alumina
+ Corrosion Control
+ Pre-Oxidation
POD Reverse Osmosis
+ Pre-Oxidation
POU Activated Alumina
+ Pre-Oxidation
Regionalization
Alternate Source
Annual Cost
assoc. w/upgrade
($/HH)
305
305
156
246
70
327
261
256
9
1
Annual Baseline
Median Water
Cost ($/HH)
195
Annual Total Cost
($/HH)
500
500
351
441
265
522
456
451
204
196
MHI ($)
29,852
Annual Total Cost
as a % of MHI
1.68
1.68
1.18
1.48
0.89
1.75
1.53
1.51
0.68
0.66
NOTE: Technologies appearing in BOLD are not considered affordable
$/HH = Dollars per household; MHI = Median household income (annual)
* Source: National-Level Affordability Criteria Under the 1996 Amendments to the Safe Drinking Water Act (1999 $)
4-14
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5.0 REFERENCES
AWWA (1990). Wateji£juaUry_andJIiei^^
McGraw-Hill Publishing Company, New York.
AWWARF (1998). AraerjdcJie^ahil^^
Amy, G.L., M. Edwards, M. Benjamin, K. Carlson, J. Chwirka, P. Brandhuber, L. McNeill
and F. Vagliasindi, Draft Report, April 1998.
Cheng, R.C., S. Liang, H-C Wang, and J. Beuhler (1994). "Enhanced Coagulation for Arsenic
Removal," J.AWWA, 9:79-90.
Clifford, D., and C.C. Lin (1995). "Ion Exchange, Activated Alumina, and Membrane Processes for
Arsenic Removal from Groundwater," Proceedings of the 45th Annual Environmental
Engineering Conference, University of Kansas, February 1995.
DPRA, Inc. (1993). Small System Byproducts Treatment and Disposal Cost Document, Prepared
for USEPA Office of Ground Water and Drinking Water.
EPA (1993). Very Small Systems Best Available Technology Cost Document. USEPA Office of
Ground Water and Drinking Water, Drinking Water Technology Branch.
EPA (1998a). National Level Affordability Criteria Under the 1996 Amendments to the Safe
Drinking Water Act, USEPA Office of Ground Water and Drinking Water (April, 1998).
EPA (1998b). Small Systems Compliance Technology List for the Non-Microbial Contaminants,
USEPA Office of Ground Water and Drinking Water.
EPA (1998c). Water Treatment Costs Development (Phase I): Road Map to Cost Comparisons,
USEPA Office of Ground Water and Drinking Water.
EPA (1999). Technologies and Costs for the Removal of Arsenic from Drinking Water, USEPA
Office of Ground Water and Drinking Water (November, 1999).
Fox, K.R. and TJ. Sorg (1987). "Controlling Arsenic, Fluoride, and Uranium by Point-of-Use
Treatment," J. A WWA, 10:81 -84.
Fox, K.R. (1989). "Field Experience with Point-of-Use Treatment Systems for Arsenic Removal,"
J.AWWA, 2:94-101.
Hering, J.G., and V.Q. Chiu (1998). "The Chemistry of Arsenic: Treatment and Implications of
Arsenic Speciation and Occurrence," AWWA Inorganic Contaminants Workshop, San
Antonio, TX, February 23-24, 1998.
5-1
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Lomaquahu, E.S., and A.H. Smith (1998). "Feasibility of New Epidemiology Studies on Arsenic
Exposures at Low Levels," AWWA Inorganic Contaminants Workshop, San Antonio, TX,
February 23-24,1998.
Subramanian, K.S., T. Viraraghavan, T. Phommavong, and S. Tanjore (1997). "Manganese
Greensand for Removal of Arsenic in Drinking Water," Water Quality Research Journal
Canada, 32:3:551-561.
Vickers, J.C., A. Braghetta, and R.A. Hawkins (1997). "Bench Scale Evaluation of Microfilitration
for Removal of Particles and Natural Organic Matter," Proceedings, Membrane Technology
Conference, February 23-26,1997, New Orleans, LA.
5-2
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APPENDIX A
RELEVANT PARTS OF SECTION 1412 OF THE 1996 SDWA AMENDMENTS
-------
SEC. 105. TREATMENT TECHNOLOGIES FOR SMALL SYSTEMS.
SEC. 1412.(b)(4)(E) (42 U.S.C. 300g-l(b)(4)(E)) is amended by adding at the end the following:
(ii) LIST OF TECHNOLOGIES FOR SMALL SYSTEMS.-The Administrator shall include
in the list any technology, treatment technique, or other means that is affordable, as
determined by the Administrator in consultation with the States, for small public water
systems serving-
(I) a population of 10,000 or fewer but more than 3,300;
(II) a population of 3,300 or fewer but more than 500; and
(III) a population of 500 or fewer but more than 25;
and that achieves compliance with the maximum contaminant level or treatment
technique, including packaged or modular systems and point-of-entry or point-of-use
treatment units. Point-of-entry and point-of-use treatment units shall be owned, controlled
and maintained by the public water system or by a person under contract with the public
water system to ensure proper operation and maintenance and compliance with the
maximum contaminant level or treatment technique and equipped with mechanical
warnings to ensure that customers are automatically notified of operational problems. The
Administrator shall not include in the list any point-of-use treatment technology,
treatment technique, or other means to achieve compliance with a maximum contaminant
level or treatment technique requirement for a microbial contaminant (or an indicator of
a microbial contaminant). If the American National Standards Institute has issued product
standards applicable to a specific type of point-of-entry or point-of-use treatment unit,
individual units of that type shall not be accepted for compliance with a maximum
contaminant level or treatment technique requirement unless they are independently
certified in accordance with such standards. In listing any technology, treatment
technique, or other means pursuant to this clause, the Administrator shall consider the
quality of the source water to be treated.
(iii) LIST OF TECHNOLOGIES THAT ACHIEVE COMPLIANCK-Except as provided
in clause (v), not later than 2 years after the date of enactment of this clause and after
consultation with the States, the Administrator shall issue a list of technologies that
achieve compliance with the maximum contaminant level or treatment technique for each
category of public water systems described in subclauses (I), (II), and (III) of clause (ii)
for each national primary drinking water regulation promulgated prior to the date of
enactment of this paragraph.
(iv) ADDITIONAL TECHNOLOGIES.-The Administrator may, at any time after a national
primary drinking water regulation has been promulgated, supplement the list of
technologies describing additional or new or innovative treatment technologies that meet
the requirements of this paragraph for categories of small public water systems described
A-l
-------
in subclauses (I), (II), and (III) of clause (ii) that are subject to the regulation.
(v) TECHNOLOGIES THAT MEET SURFACE WATER TREATMENT RULE.-Within
one year after the date of enactment of this clause, the Administrator shall list
technologies that meet the Surface Water Treatment Rule for each category of public
water systems described in subclauses (I), (II), and (III) of clause (ii).
SEC. 111. TECHNOLOGY AND TREATMENT TECHNIQUES.
(a) Variance Technologies.-Section 1412(b) (42 U.S.C. 300g-l(b)) is amended by adding the
following new paragraph after paragraph (14):
(15) VARIANCE TECHNOLOGIES.-
(A) IN GENERAL.-M the same time as the Administrator promulgates a national primary
drinking water regulation for a contaminant pursuant to tlu's section, the Administrator
shall issue guidance or regulations describing the best trealment technologies, treatment
techniques, or other means (referred to in this paragraph as Variance technology') for the
contaminant that the Administrator finds, after examination for efficacy under field
conditions and not solely under laboratory conditions, an; available and affordable, as
determined by the Administrator in consultation with the States, for public water systems
of varying size, considering the quality of the source water to be treated. The
Administrator shall identify such variance technologies for public water systems serving--
(i) a population of 10,000 or fewer but more than 3,300;
(ii) a population of 3,300 or fewer but more than 500; and
(iii) a population of 500 or fewer but more than 25,
if, considering the quality of the source water to be treated, no treatment technology is
listed for public water systems of that size under paragraph (4)(E). Variance technologies
identified by the Administrator pursuant to this paragraph may not achieve compliance
with the maximum contaminant level or treatment teclmique requirement of such
regulation, but shall achieve the maximum reduction or mactivation efficiency that is
affordable considering the size of the system and the quality of the source water. The
guidance or regulations shall not require the use of a technology from a specific
manufacturer or brand.
(B) LIMIT A TION.-The Administrator shall not identify any variance technology under this
paragraph, unless the Administrator has determined, considering the quality of the source
water to be treated and the expected useful life of the technology, that the variance
technology is protective of public health.
(C) ADDITIONAL INFORMATION.-The Administrator shall include in the guidance or
regulations identifying variance technologies under this paragraph any assumptions
supporting the public health determination referred to in snbparagraph (B), where such
A-2
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assumptions concern the public water system to which the technology may be applied, or
its source waters. The Administrator shall provide any assumptions used in determining
affordability, taking into consideration the number of persons served by such systems. The
Administrator shall provide as much reliable information as practicable on performance,
effectiveness, limitations, costs, and other relevant factors including the applicability of
variance technology to waters from surface and underground sources.
(D) REGULATIONS AND GUIDANCE.-Not later than 2 years after the date of enactment
of this paragraph and after consultation with the States, the Administrator shall issue
guidance or regulations under subparagraph (A) for each national primary drinking water
regulation promulgated prior to the date of enactment of this paragraph for which a
variance may be granted under section 1415(e). The Administrator may, at any time after
a national primary drinking water regulation has been promulgated, issue guidance or
regulations describing additional variance technologies. The Administrator shall, not less
often than every 7 years, or upon receipt of a petition supported by substantial
information, review variance technologies identified under this paragraph. The
Administrator shall issue revised guidance or regulations if new or innovative variance
technologies become available that meet the requirements of this paragraph and achieve
an equal or greater reduction or inactivation efficiency than the variance technologies
previously identified under this subparagraph. No public water system shall be required
to replace a variance technology during the useful life of the technology for the sole
reason that a more efficient variance technology has been listed under this subparagraph.
(b) Availability of Information on Small System Technologies- Section 1445 (42 U.S.C. 300J-4)
is amended by adding the following new subsection after subsection (g):
(h) AVAILABILITY OF INFORMATION ON SMALL SYSTEM TECHNOLOGIES.-?or
purposes of sections 1412(b)(4)(E) and 1415(e) (relating to small system variance program), the
Administrator may request information on the characteristics of commercially available treatment
systems and technologies, including the effectiveness and performance of the systems and
technologies under various operating conditions. The Administrator may specify the form, content,
and submission date of information to be submitted by manufacturers, States, and other interested
persons for the purpose of considering the systems and technologies in the development of
regulations or guidance under sections 1412(b)(4)(E) and 1415(e).
A-3
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APPENDIX B
BFJ.F.VANT PAT?TS OF SRCTTON 1415 OFTHF, 1996 SDWA AMENDMENTS
-------
SEC. 116. SMALL SYSTEMS VARIANCES.
Section 1415 (42 U.S.C. 300g-4) is amended by adding at the end the following:
(e) SMALL SYSTEM VARIANCES.-
(1) 77V GENERAL.-A State exercising primary enforcement responsibility for public water
systems under section 1413 (or the Administrator in nonprimacy States) may grant a variance
under this subsection for compliance with a requirement specifying a maximum contaminant
level or treatment technique contained in a national primary drinking water regulation to-
(A) public water systems serving 3,300 or fewer persons;
(B) with the approval of the Administrator pursuant to paragraph (9), public water systems
serving more than 3,300 persons but fewer than 10,000 persons, if the variance meets each
requirement of this subsection.
(2) A VAILABILITY OF VARIANCES.-A public water system may receive a variance pursuant
to paragraph (1), if-
(A) the Administrator has identified a variance technology under section 1412(b)(l 5) that is
applicable to the size and source water quality conditions of the public water system;
(B) the public water system installs, operates, and maintains, in accordance with guidance or
regulations issued by the Administrator, such treatment technology, treatment technique,
or other means; and
(C) the State in which the system is located determines that the conditions of paragraph (3)
are met.
(3) CONDITIONS FOR GRANTING VARIANCES.-A variance under this subsection shall be
available only to a system--
(A) that cannot afford to comply, in accordance with affordability criteria established by the
Administrator (or the State in the case of a State that has primary enforcement
responsibility under section 1413), with a national primary drinking water regulation,
including compliance through--
(i) treatment;
(ii) alternative source of water supply; or
(iii) restructuring or consolidation (unless the Administrator (or the State in the case of
a State that has primary enforcement responsibility under section 1413) makes a
written determination that restructuring or consolidation is not practicable); and
(B) for which the Administrator (or the State in the case of a State that has primary
enforcement responsibility under section 1413) determines that the terms of the variance
ensure adequate protection of human health, considering the quality of the source water
B-l
-------
for the system and the removal efficiencies and expected useful life of the treatment
technology required by the variance.
(4) COMPLIANCE SCHEDULES.-A. variance granted under this subsection shall require
compliance with the conditions of the variance not later than 3 years after the date on which
the variance is granted, except that the Administrator (or the State in the case of a State that
has primary enforcement responsibility under section 1413) may allow up to 2 additional years
to comply with a variance technology, secure an alternative source of water, restructure or
consolidate if the Administrator (or the State) determines that additional time is necessary for
capital improvements, or to allow for financial assistance pro\ided pursuant to section 1452
or any other Federal or State program.
(5) DURATION OF VARIANCES.-The Administrator (or the State in the case of a State that has
primary enforcement responsibility under section 1413) shall review each variance granted
under this subsection not less often than every 5 years after the compliance date established
in the variance to determine whether the system remains eligible for the variance and is
conforming to each condition of the variance.
(6) INELIGIBILITYFOR VARIANCES.-^ variance shall not be available under this subsection
for-
(A) any maximum contaminant level or treatment technique for a contaminant with respect
to which a national primary drinking water regulation was promulgated prior to January
1,1986; or
(B) a national primary drinking water regulation for a microbial contaminant (including a
bacterium, virus, or other organism) or an indicator or treatment technique for a microbial
contaminant.
(7) REGULATIONS AND GUIDANCE.-
(A) IN GENERAL.-Not later than 2 years after the date of enactment of this subsection and
in consultation with the States, the Administrator shall promulgate regulations for
variances to be granted under this subsection. The regulations shall, at a minimum,
speciry
(i) procedures to be used by the Administrator or a State to grant or deny variances,
including requirements for notifying the Administrator and consumers of the public
water system that a variance is proposed to be granted (including information
regarding the contaminant and variance) and requirem(aits for a public hearing on the
variance before the variance is granted;
(ii) requirements for the installation and proper operation of variance technology that is
identified (pursuant to section 1412(b)(15)) for small systems and the financial and
technical capability to operate the treatment system, including operator training and
B-2
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certification;
(iii) eligibility criteria for a variance for each national primary drinking water regulation,
including requirements for the quality of the source water (pursuant to section
1412(b)(15)(A)); and
(iv) information requirements for variance applications.
(B) AFFORDABILITY CRITERL4.-Not later than 18 months after the date of enactment of
the Safe Drinking Water Act Amendments of 1996, the Administrator, in consultation
with the States and the Rural Utilities Service of the Department of Agriculture, shall
publish information to assist the States in developing affordability criteria. The
affordability criteria shall be reviewed by the States not less often than every 5 years to
determine if changes are needed to the criteria.
(8) REVIEW BY THE ADMINISTRATOR.-
(A) IN GENERAL.-Ths Administrator shall periodically review the program of each State
that has primary enforcement responsibility for public water systems under section 1413
with respect to variances to determine whether the variances granted by the State comply
with the requirements of this subsection. With respect to affordability, the determination
of the Administrator shall be limited to whether the variances granted by the State comply
with the affordability criteria developed by the State.
(B) NOTICE AND PUBLICATION.-If'the Administrator determines that variances granted
by a State are not in compliance with affordability criteria developed by the State and the
requirements of this subsection, the Administrator shall notify the State in writing of the
deficiencies and make public the determination.
(9) APPROVAL OF VARIANCES.-^. State proposing to grant a variance under this subsection
to a public water system serving more than 3,300 and fewer than 10,000 persons shall submit
the variance to the Administrator for review and approval prior to the issuance of the variance.
The Administrator shall approve the variance if it meets each of the requirements of this
subsection. The Administrator shall approve or disapprove the variance within 90 days. If the
Administrator disapproves a variance under this paragraph, the Administrator shall notify the
State in writing of the reasons for disapproval and the variance may be resubmitted with
modifications to address the objections stated by the Administrator.
(10) OBJECTIONS TO VARIANCES.-
(A) BY THE ADMINISTRATOR.-The Administrator may review and object to any variance
proposed to be granted by a State, if the objection is communicated to the State not later
than 90 days after the State proposes to grant the variance. If the Administrator objects
to the granting of a variance, the Administrator shall notify the State in writing of each
basis for the objection and propose a modification to the variance to resolve the concerns
B-3
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of the Administrator. The State shall make the recommended modification or respond in
writing to each objection. If the State issues the variance without resolving the concerns
of the Administrator, the Administrator may overturn the State decision to grant the
variance if the Administrator determines that the State decision does not comply with this
subsection.
(B) PETITION BY CONSUMERS. -Not later than 30 days after'a State exercising primary
enforcement responsibility for public water systems under section 1413 proposes to grant
a variance for a public water system, any person served by the system may petition the
Administrator to object to the granting of a variance. The Administrator shall respond to
the petition and determine whether to object to the variance under subparagraph (A) not
later than 60 days after the receipt of the petition.
(C) TIMING.-No variance shall be granted by a State until the later of the following:
(i) 90 days after the State proposes to grant a variance.
(ii) If the Administrator objects to the variance, the date on which the State makes the
recommended modifications or responds in writing to each objection.
B-4
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