'2: 

(laUnited States 

Environmantal Protection Office of Water EPA 815-R-98-002 

Agency 4607 September 1998 

\f/EPA Small System 

Compliance Technology 

List for the Non-Microbial 

Contaminants Regulated 

Before I996 

$ I ,. 1 'I 

r r* I . i 

_c' B.85 

I 

i 
TABLE OF CONTENTS 

Table of Contents 

List of Figures 

1. Introduction 

Section 1.1: Safe Drinking Water Act Implementation 

Section 1.2: Need for a Small System Technology Requirement 

Section 1.3: Small System Treatment Technology Requirements 

of the 1996 SDWA 

Section 1.4: Point-of-Entry and Point-of-Use Treatment Units as 

Compliance Technologies 

Section 1.5: Format and Content of this Small System Compliance 

Technology List 

Section 1.6: Stakeholder Involvement 

Section 1.7: Organization of the Document 

2. Background on Existing National Primary Drinking Water Regulations 

.. 

11 

iv 

1 

1 

2 

3 

10 

10 

11 

12 

14 

15 

15 

16 

16 

16 

16 

17 

18 

Section 2.1 

Section 2.2 

Section 2.3 

Section 2.4 

Section 2.5 

Section 2.6 

Section 2.7 

Section 2.8 

Section 2.9 

National Interim Primary Drinking Water Regulations 

(NIPDWRs) (40 FR 59566) 

Radionuclides NIPDWRs (41 FR 28402) 

Trihalomethanes NIPDWRs (44 FR 68624) 

Fluoride Rule (5 1 FR 11396) 

Phase I Rule (52 FR 25690) 

Phase I1 Rule (56 FR 3526) and 

Phase IIb Rule (56 FR 30266) 

Lead and Copper Rule (56 FR26460) 

Phase V Rule (57 FR 3 1776) 

Summary of National Primary Drinking Water Regulations 18 

3. Descriptions of Technologies 22 

4. Affordable Technology Determinations 42 

Section 4.1 National-Level Affordability Criteria 42 

Section 4.2 Affordable Technology Analysis using National-Level 

Affordability Criteria 46 

5. Small Systems Compliance Technologies for Inorganic Contaminants, 

including Corrosion By-products 48 

Section 5.1: Background 48 

a 
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Section 5.2: Evaluation of Technologies 

Section 5.3: Small Systems Compliance Technologies List 

Section 5.4: Emerging Technologies 

6. Small Systems Compliance Technologies for Radionuclides 

Section 6.1: Background 

Section 6.2: Evaluation of Technologies 

Section 6.3: Small Systems Compliance Technologies List 

Section 6.4: Emerging Technologies 

7. Small Systems Compliance Technologies for Volatile Organic Contaminants 

Section 7.1 : Background 

Section 7.2: Evaluation of Technologies 

Section 7.3: Small Systems Compliance Technologies List 

Section 7.4: Emerging Technologies 

8. Small Systems Compliance Technologies for Other Synthetic 

Organic Contaminants 

Section 8.1: Background 

Section 8.2: Evaluation of Tcchnologies 

Section 8.3: Small Systems Compliance Technologies List 

Section 8.4: Emerging Technologies 

Appendix: Relevant Statutop Sections 

50 

56 

61 

65 

65 

67 

81 

83 

86 

86 

87 

90 

93 

96 

96 

97 

98 

102 

106 

3 
LIST OF FIGURES 

Chapter 1 

Figure 1. Small System Requirements: Compliance vs. 

Variance Technologies 

Figure 2. Affordable Compliance Technologies 

Figure 3. Compliance Technologies (No Affordability) 

Chapter 6 

Figure 1. Disposal of Liquid Wastes 78 

Figure 2. Disposal of Solid Wastes 80 

4 
-- 

1. INTRODUCTION 

Section 1.1: Safe Drinking Water Act Implementation 

The Safe Drinking Water Act (SDWA) Amendments were signed by the President on August 

6, 1996. The 1996 SDWA contains over 70 statutory deadlines for the Environmental Protection 

Agency (EPA), presenting a challenging set of activities for EPA, States, Indian tribes, public water 

systems, and other stakeholders. 

Due to the 1996 SDWA’s emphasis on public information and participation, as well as EPA’s 

desire to seek a broad range of public input, the stakeholder process that was begun during the 1995 

drinking water program redirection effort has been greatly expanded. To provide focus, EPA has 

grouped many of the statutory deadlines into more general project areas. Each of these areas has a 

broad set of stakeholders that will provide information and comments. 

One of these project areas focuses on small systems treatment technologies and is being 

addressed by EPA‘s Treatment Technology Team. This project area is a part of one of the primary 

objectives of the 1996 SDWA, which is to more fully consider the needs of small drinking water 

systems in developing and implementing drinlung water regulations. The mission of the Treatment 

Technology Team is to identify andor develop high quality, cost-effective treatment technologies 

to meet regulation development and program implementation objectives and deadlines. The team’s 

short-term goals are to prepare: ( I ) by August 6, 1997. the list of technologies that small systems can 

use to comply with the Surface M’ater Treatment Rule (SWTR); (2) by August 6, 1998, the list of 

technologies that small systems can use to comply with all of the other (pre-August 1996) National 

Primary Drinking Water Regulations (NPDWRs); and (3) by August 6, 1998, the list of variance 

technologies for small systems for the appropriate NPDWRs. The long-term goals include the 

identification of: ( 1) small system compliance and variance technologies for all future regulations; 

(2) best available technologies (RATS)for larger systems in future regulations; and (3) emerging 

technologies that should be evaluakd as potential compliance or variance technologies for both 

existing and future regulations. 

The Environmental Protection Agency met the first of these short-term goals in August, 1997. 

A Federal Register notice dated August 1 1, 1997 published the compliance technology list for the 

surface water treatment rule (EPA 1997a). The notice also announced the availability of a guidance 

manual entitled ”Compliance Technology List for the Surface Water Treatment Rule” (EPA 1997b)’ 

which provided more detailed background information supporting the list of technologies published 

in the Federal Recister notice. 

The Environmental Protection Agency updated the list of compliance technologies for the 

SWTR and published the list of compliance technologies for the total coliform rule in a Federal 

Register notice on August 6, 1998 (EPA 1998a). EPA is also publishing an update to the guidance 

manual that supported the original SWTR list of compliance technologies. The updated guidance 

manual is entitled “Compliance Technology List for the Surface Water Treatment Rule and the Total 

5 
Coliform Rule” (EPA 1998b). This document covers both update of the SWTR list and the 

compliance technologies identified for the Total Coliform Rule (TCR). These have been grouped 

into one publication as they both address microbial contaminants and their indicators in drinking 

water. The list of compliance technologies for the total coliform rule is one of the lists required by 

Section 1412(b)(4)(E)(iii) of the SDWA. 

The Environmental Protection Agency met both the second and hrd of the short-term goals in 

August 1998. A Federal Register notice dated August 6, 1998 (EPA 1998a) published the list of 

compliance technologies that systems can use to comply with all of the other NPDWRs and the 

findings concerning variance technologies for the contaminants regulated before 1996. EPA did not 

list any variance technologies for contaminants regulated before 1996 in this notice. This guidance 

manual was developed to provide more detail on the list of compliance technologies for the nonmicrobial contaminants regulated before 1996. A guidance manual entitled “Variance Technology 

Findings for Contaminants Regulated before 1996”has been prepared to describe the procedures that 

were used to make the determination that there would be no variance.technologies for contaminants 

regulated before 1996 at this time (EPA 1998~). 

Section 1.2: Need for a Small System Technology Requirement 

The 1986 SDWA identified a process for setting maximum contaminant levels (MCLs) as close 

to the maximum contaminant level goal (MCLG) as is “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 met this feasibility criterion are called “best available technologies” (BATS) 

and are listed in the final regulations. This process is retained in the 1996 SDWA. All of the 

existing MCLs covered in this document were developed using this process. 

One of the regulations covered in this document is the Lead and Copper Rule, which requires 

compliance with a treatment technique rule rather than an MCL. Section 1412(b)(7)(A) of the 1986 

SDWA listed the conditions under which a treatment technique could be promulgated in lieu of an 

MCL. When these conditions are met, the Act states that “. . .the Administrator must identify those 

treatment techniques which, in the Administrator’s judgement, would prevent known or anticipated 

adverse effects on the health of persons to the extent feasible”. The definition of feasible listed 

above would also apply in the technology determinations for treatment techniques like the Lead and 

Copper Rule. 

There is one other treatment technique rule in the group of non-microbial contaminants 

regulated before 1996: epichlorohydrin and acrylamide are regulated through the Phase I1 Rule (see 

Chapter 2) via a treatment technique rather than with MCLs. Unlike the technology-based treatment 

techniques established by the SWTR or the Lead and Copper Rule, the treatment techniques for these 

two contaminants are not based on the use of treatment technologies to remove or reduce the 

contaminant concentration. Instead, the treatment technique for these two contaminants requires 

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. 

LI 
those public water systems using acrylamide or epichlorohydrin in a treatment process to provide 

written certification annually to the State that the combination of dose and monomer level does not 

exceed specified levels. Since technologies are not being utilized for these NPDWRs, neither 

compliance nor variance technologies will be listed for these contaminants. 

Before the 1996 Amendments, cost assessments for the treatment technology feasibility 

determinations were based upon impacts to regional and large metropolitan water systems. This 

protocol was established when the SDWA was originally enacted in 1974 (Congressional Record 

1974) and was carried over when the Act was amended in 1986 (Congressional Record 1986). The 

population size categories that EPA has used to make feasibility determinations for regional and 

large metropolitan water systems has varied among different regulation packages. The most 

common population size categories used were 50,000 - 75,000 people and 100,000 - 500,000people. 

The techcal demands and costs associated with technologies that are feasible based on regional and 

large metropolitan water systems often make these technologies inappropriate for small systems. 

The 1996 Amendments attempt to redress this problem in part thrsugh the previously described 

series of small system compliance technologies. This guidance is the second part of a series of 

publications aimed at helping small systems comply with the existing regulations. 

Section 1.3: Small System Treatment Technology Requirements of the 1996 SDWA 

Since large systems were used as the basis for the feasibility determinations, some of the existing 

BATSfor MCLs and the existing treatment techniques may not be appropriate for small systems. In 

response to this concern, the 1996 SDWA specifically requires EPA to make technology assessments, 

relevant to the three categories of small systems respectively for both existing and future regulations, 

in addition to the pre-1996 Amendments BAT protocol. The three population-served size categories 

of small systems defined by the 1996 SDWA are: 10,000 - 3,301 persons, 3,300 - 501 persons, and 

500 - 25 persons. 

The 1996 SDWA identifies two classes of technologies for small systems: compliance 

technologies and variance technologies. A “compliance technology” may refer to both a technology 

or other means that is affordable and that achieves compliance with the MCL and to a technology 

or other means that satisfies a treatment technique requirement. Possible compliance technologies 

include packaged or modular systems and point-of-entry (POE) or point-of-use (POU) treatment 

units [see Section 1412(b)(4)(E)(ii)]. Variance technologies are only specified for those system 

size/source water quality combinations for which there are no listed compliance technologies 

[Section 1412(b)(15)(A)]. Thus, the listing of a compliance technology for a size category/source 

water combination prohibits the listing of variance technologies for that combination. While 

variance technologies may not achieve compliance with the MCL or treatment technique 

requirement, they must achieve the maximum reduction or inactivation efficiency that is affordable 

considering the size of the system and the quality of the source water. Variance technologies must 

also achieve a level of contaminant reduction that is protective of public health [Section 

1412(b)(15)(B)]. 

I 4-
. 

The variance procedure for small systems has been significantly revised in the 1996 SDWA. 

The 1986 SDWA required non-compliant water systems to install a “best available technology” 

(BAT) before applying for a variance: if they were unable to meet the MCL after treatment, they 

could then apply for a variance. The 1996 Amendments have given the variance option additional 

flexibility in that variances can be applied for and granted before the variance technology is installed, 

thus ensuring that the system will have a variance before it invests in treatment. This new variance 

procedure applies specifically to small water systems (systems serving less than 10,000) and is 

referred to as the “small system variance”. The difference between the original variance and the 

small system variance procedures is the basis for the feasibility (technical and affordability) 

determination. For the former, large systems are the basis; for the latter, small systems are the basis. 

If there are no affordable compliance technologies listed by the EPA for a small system size 

category/source water quality combination and EPA has identified small systems variances 

technologies for that combination, then the system may apply for a small system variance. One of 

the criteria for obtaining a small system variance is that the system must install a variance 

technology listed for that size categov/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. 

There are some additional statutory requirements for small system variances that affect the 

listing of variance technologies. Small system variances are not available for any MCL or treatment 

technique for a contaminant with respect to u.hich a national primary drinking water regulation was 

promulgated prior to January 1. 1986 [Section 1415(e)(6)(A)]. The final Variance and Exemption 

Rule provides EPA’s interpretation of this requirement (EPA 1998d). In a case where a pre-1986 

NPDWR is updated, EPA has determined that small system variances would not be available if the 

pre-I986 MCL is either retained or raised. Small system variance would only be available if the pre1986 MCL was lowered (could apply to updates of the existing arsenic and radionuclides MCLs if 

the pre-1986 MCLs are lowered). Nor arc small system variances allowable for NPDWRs (including 

treatment techniques) for microbial contaminants or microbial contaminant indicators, i.e., bacteria, 

viruses, other regulated pathogens. or regulated indicators, like turbidity [Section 1415(e)(6)(B)]. 

Variance technologies were not specified for those contaminants for which small system variances 

are not allowable by the SDWA. 

The process for identifying compliance and variance technologies for future regulations was 

summarized in the preceding paragraphs. The language in the 1996 SDWA Amendments is different 

for the existing regulations. There are two mandatory lists of compliance technologies that will be 

developed for the existing rules. B). August 6, 1997, the Administrator was required to list 

technologies that meet the SWTR for each of the three size categories [Section 1412(b)(4)(E)(v)]. 

By August 6, 1998, after consultation with the States, the Administrator was required to issue a list 

of technologies that achieve compliance with the MCLs or treatment technique requirements for 

other existing NPDWRs. Also by August 6, 1998, after consultation with the States, the 

Administrator was required to issue guidance or regulations for variance technologies for the existing 

NPDWRs for which a small system variance can be granted. Figure I summarizes the requirements 

for compliance and variance technologies and differentiates between existing and future regulations. 

. 

. 

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FIGURE 1 

SMALL SYSTEM REQUIREMENTS 

COMPLIANCE VS. VAFUANCE TECHNOLOGIES 

COMPLIANCE VARIANCE 

TECHNOLOGY TECHNOLOGY 

-_ EXISTING 

REGULATIONS: 

Meet affordable 

technology criteria 

Source Water Quality 

Endpoint 

Health Requirements 

Separate from MCL 

FUTURE 

REGULATIONS: 

Meet affordable 

technology criteria 

Source Water Quality 

Endpoint 

Health Requirements 

Separate from MCL 

Not Explicitly Required 

GOOD 

MCL 

NONE 

Required 

GOOD 

MCL 

NONE 

Inherently Required 

POOR 

Maximum Reduction 

that is Affordable 

Must be protective of 

public health 

Required 

POOR 

Maximum Reduction 

that is Affordable 

Must be protective of 

public health 

The two major concerns regarding technologies for small systems are affordability and technical 
complexity. Regarding affordability, per household costs tend to be higher for the smaller system 

customers for most central treatment technologies, leading to many cases where small systems 

simply cannot afford to install a prescribed technology. Regarding technical complexity, small 

systems often do not have access to well-trained water system operators. Although the statute is 

silent concerning whether small system compliance technologies for existing regulations should be 

affordable, EPA believes that the better approach under the statute is that affordability should be 

evaluated for future regulations and existing regulations where the statute allows variance 

technologies. If the candidate technologies are not evaluated against an affordable technology 

criterion, then compliance technologies would exist for all of the existing regulations regardless of 

the source water quality. The existing best available technologies (BATS)or treatment techniques 

would automatically become the compliance technologies for small systems, which was the case 

prior to the 1996 Amendments. EPA does not believe that result to be what Congress intended. As 

a result, EPA will 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. When affordable compliance technologies are idetltified for these contaminants, 

technologies that can achieve compliance but did not meet the affordability criterion will also be 

identified. This is consistent with EPA’s approach to the compliance technology Iist for the SWTR 

and the views of stakeholders. EPA will list these technologies and indicate that they did not pass 

the affordable technology criterion rather than limit the information on options available to systems. 

For those regulations where the SDWA prohibits small system variances or variance technologies, 

affordability will not be considered in the evaluation of compliance technologies because there 

would be no function to doing so (all systems subject to the rule must comply). 

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The flow chart in Figure 2 shmvs the role of the affordable technology criteria in the treatment 

technology arena. The prim*, function of the criteria is to determine whether a system of a given 

size/source water quality combination should proceed down the compliance or variance technology 

pathway (assuming an affordablc \.ariance technology can be identified). The secondary function 

is to define the universe of technologies within the compliance or variance technology pathway. 

These affordable technology critcria are different from the affordability criteria to be used by States 

in granting small system varianccs under Section 1415(e). The criteria used by States will be 

applicable to individual systems (“system-level affordability criteria”). Options that States can use 

for system-level affordability criteria were developed in the Small System NDWAC Working Group 

process and are available in ”Information for States on Developing Affordability Criteria for 

Drinking Water.” This document was published on February 4, 1998 (EPA 1998e) and can be 

downloaded at http:llwv.epq.gov/OG WDWlsmal1syslafford.html. In contrast, the affordable . technology criteria to be developed under Section 1412(b)(4) can be viewed as “national-level 

affordability criteria” (EPA 19980. Technologies that meet the national-level criteria may not be - affordable for a particular system within the size category (“system-level affordability criteria”). 

In these cases. the system should explore the options of restructuring or finding an alternate source 

of water. If these options are not available, grants and exemptions may be available. These issues 

are discussed in more detail in Chapter 4. The respective roles of the national-level and system-level 

affordability criteria are summarized in Figure 2. 
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FIGURE 2 

AFFORDABLE COMPLIANCE TECHNOLOGIES* 

System Out 

of Complianc 

compliance

Technology? 

I 

YES , Can

system afford 

NO 

__ ~~ 

a compliance A- technology? /’‘> Alt. Source or 

, , /’

i 

Implement

Treatment, ~

Alt Source or 

I Restructuring 

/ \\ __ -A- ~__ ’

/

/ \ 

\ 

Can System\ IS 

Restructure ‘ -I/’Restructuring 

or afford Alt ,)As YES \ practicable? 

Source? ‘\ /’ / . \

\/ NO __ ~~ 7 - ~ 

NO

I Imp1ement 

Affordable 

__ _- ~ 

-

NO 

’Are‘\ 

* variance 

Implement Exemptions technology 

Compliance 4 Available,,,, -0 ~ 

Technology .. 1. / 

, 

_ _ A~ YES ­

~ --LExemption

Process (State 

sets schedule 

for compllance 

1-

Has 

exemption , Obtain Small 

NO- period run *y-ES - System Varlanc 

, out? /, 

J

/’ 

YES 

*NOTE: This approach covers the regulations that pass all of the 

screening criteria �or variance technologies. 
For those existing regulations where the SDWA prohibits small system variances or variance 

technologies, the candidate technologies will not be evaluated against an affordable technology 

criterion. There are two statutory prohibitions on small system variances and one prohibition on 

variance technologies. As previously mentioned. small system variances are not available for any 

NPDWR for a microbial contaminant (or indicator). The compliance technologies for the six 

microbial Contaminantswere not evaluated against the affordable technology criterion (EPA 1998b). 

Small system variances are also not available for any MCL or treatment technique with respect to 

which a NPDWR was promulgated prior to January 1, 1986. Technologies were not evaluated 

against an affordable technology criterion for the 12 contaminantswhere the pre-I986 MCL has been 

retained or raised. The statutory prohibition on variance technologies is found in Section 

1412(b)(l5)(B) of the SDWA. 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. For 19 contaminants, it was determined that in order to be protective of public 

health, the MCL had to be met. Thus, affordable compliance technology determinations were not 

done for 31 of the 7 1 contaminants with listed compliance technologies or for the six microbial 

contaminants, which are covered in another document. The flow chart in Figure 3 shows the 

simplified process for these regulations. In this figure, “no affordability” refers to the fact that 

affordability considerations are not allowed for these contaminants. 

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FIGURE 3 

COMPLIANCE TECHNOLOGIES (No affordability)" 

System Out 

of Compliance 

. 

. 

Imp1ement 

Alt. Source 

or 

A -_ 

7­

Restructuring ~ 

,/"an System 

I' Restructure 

or afford Alt 

\\/ 

__ ~ 

NO 

,1, -\ 

NO ,,' Are '\. -~_______ . ~ ~. Exemptions *,L-------­

~~ .-L- \..\/ 

Implement YES 

Compliance 

Technology ~ ~ 7- ~ ~ .~.-~~ 

Exemption

--r­Process (State

sets schedule 

for compliance 

~~ 

Has 

exemption '> - ~__ _. NO period ru out? ,/' YES 

-. 

YES 

*NOTE: This approach covers all regulations where the contaminant 

failed to meet one of the screening criteria for variance technologies. 
Section 1.4: Point-Of-Entry and Point-of-Use Treatment Units as Compliance Technologies 

Section 1412(b)(4)(E)(ii) of the SDWA identifies both Point-of-Entry (POE) and Point-of-Use 

(POU) treatment units as options for compliance technologies. A POE treatment device is a 

treatment device applied to the drinking water entering a house or building for the purpose of 

reducing contaminants in the drinking water distributed throughout the house or building. A POU 

treatment device is a treatment device applied to a single tap used for the purpose of reducing 

contaminants in drinking water at that one tap. POU devices are typically installed at the kitchen 

tap. 

The SDWA identifies requirements that must be met when POU or POE units are used by a 

water system to comply with a NPDWR. Section 1412(b)(4)(E)(ii) stipulates that “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 MCL or treatment technique and equipped with mechanical 

warnings to ensure that customers are automatically notified of sperational problems.” Other 

conditions in this section of the SDWA include the following: “If the American National Standards 

Institute has issued product standards applicable to a specific type of POE or POU treatment unit, 

individual units of that type shall not be accepted for compliance with a MCL or treatment technique 

unless they are independently certified in accordance with such standards.” 

In order to list POU treatment units as compliance technologies, EPA had to delete the part of 

40 CFR 8 141.101 that prohibited POU devices to be used to comply with an MCL. A final rule was 

published in the Federal Register on June 1 1. 1998 (EPA 19988) deleting the prohibition on the use 

of POU devices as compliance technologies. As previously mentioned, POU devices are listed as 

compliance technologies for inorganic contaminants, synthetic organic contaminants, and 

radionuclides. POU devices are not listed for volatile organic contaminants because they do not 

address all routes of exposure. POE devices are still considered emerging technologies because of 

waste disposal and cost considerations. POE devices may be included on an updated list in 1999. 

For more detail on POU and POE devices. see the supporting document entitled “Cost Evaluation 

of Small System Compliance Options: Point-of-Use and Point-of-Entry Treatment Units” (EPA 

1998h). 

Section 1.5: Format and Content of the Small System Compliance Technology List for the 

Non-Microbial Contaminants Regulated Before 1996 

The 1996 SDWA does not specify the format for the compliance technology lists. Section 

14IZ(b)( 15)(D) states that the variance technology lists can be issued either through guidance or 

regulations. EPA believes that the compliance technology list may also be appropriately provided . through guidance for pre-August 1996 rules, rather than through rule-making. Since the listing 

provided in this guidance is meant to be informational, 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 the 

requirements of the existing non-microbial regulations. It does not over-ride any of the requirements 

I 
of those regulations. In summary, EPA has chosen to issue the list through a guidance document 

because regulation development is unnecessary and could considerably delay publication of the list. 

Issuing the list without rule-making allows EPA to meet the statutory deadline and to provide 

information to more small systems as they make their treatment technology decisions. It is also 

much easier and faster to update a guidance rather than a rule to incorporate advances in technology 

performance. 

The SDWA does not specify the content of the compliance technology lists. These initial lists 

(63 FR 42032) are very general and expand the lists of technology options listed in the existing nonmicrobial regulations. These lists may be updated to incorporate new technologies or additional 

information on parameters that can affect the selection of treatment. The lists will evolve over time, 

but will not be product-specific. The compliance technology lists will not be product-specific 

because EPA's Office of Ground Water and Drinking Water does not have the resources to review 

each product for each potential application; nor does EPA feel it would be appropriate to do so. 

Information on specific products will be available through another mechanism. EPA's Office 

of Research and Development has a pilot project under the Environmental Technology Verification 

(ETV) Program to provide treatment system purchasers with performance data from independent 

third parties. The EPA and National Sanitation Foundation International (NSF) are cooperatively 

organizing and conducting this pilot project to allow for verification testing of packaged drinking 

water treatment systems for meeting community and commercial needs. This pilot project includes 

the development of verification protocols and test plans, the independent testing and validation of 

packaged equipment, the fostering and supporting of governmentlindustry partnerships to obtain 

credible cost and performance data, and the preparation of product verification reports for widespread distribution. 

Section 1.6: Stakeholder Involvement 

EPA held a stakeholder meeting on May 18 and 19, 1998. Approximately 50 people registered 

and participated in the meeting. Key stakeholders included States, water systems, and equipment 

manufacturers. Representatives from nine States were present at the meeting (either at the meeting 

or on conference lines) and several others received the material that was sent out prior to the meeting 

for review. A draft of the "Cost Evaluation of Small System Compliance Options: Point-of-Use and 

Point-of-Entry Treatment Units" was sent out prior to the meeting. . 

During the meeting. compliance technology options were presented for each group of 

contaminants: inorganic contaminants (IOCs), volatile organic contaminants (VOCs), synthetic 

organic Contaminants (SOCs), and radionuclides. There was also a presentation on POU and POE 

devices that followed the sessions on the contaminant groups. Since most of the compliance 

technologies identified for these groups of contaminants were the BATS listed in the regulations, 

there were few significant comments on those presentations. 

One major topic discussed at the meeting was the format of the document. The two options 

I 
were separate documents for each Contaminant group or one document with separate chapters 

devoted to each contaminant group. Stakeholders preferred a document organized by contaminant 

groups rather than by individual technologies, since many technologies can treat for more than one 

contaminant group. For example, the technologies used for VOCs removal can also be used to 

remove some SOCs. There is also a lot of cross-over between technologies that can treat IOCs and 

radionuclides. 

Stakeholders reiterated that they thought the list of compliance technologies should be as 

comprehensive as possible. Rather than exclude possible options that have technical limitations, 

stakeholders preferred EPA to list the technologies along with the discussions of and guidance for 

dealing withthese limitations. Examples of limitationsinclude treatment technological complexity, 

which raises the concern of whether small systems could successfully operate complex processes. 

Stakeholders indicated that a more comprehensive compliance technology list that included more 

technology options for individual systems would be preferable to a more conservative list that 

disallows for the fact that many small systems have the capacity to operate more complex 

technologies. EPA has also incorporated this philosophy into the identification of affordable 

compliance technologies. EPA identified compliance technologies that did not meet the affordability 

criteria in addition to those that did, as discussed in Section 1.3. 

The initial lists of technologies are not intended to be definitive: systems may choose any 

technologies that meet the requirements of the regulations. In each chapter, there are technologies 

identified as “emerging technologies”that are not listed. These technologies either have data needs 

or require further evaluation before being listed as compliance technologies. Data needs are 

identified in the technology discussions in Chapter 3 and in the chapters discussing each of the 

individual contaminant groups. List updates could include new technologies and could include 

additional information regarding the already listed technologies. 

Section 1.7: Organization of the Document 

This document is organized into several chapters describing the small system compliance 

technologies for the non-microbial contaminants regulated before 1996. Chapter 1 discusses the 

requirements of the 1996 SDWA and the approach EPA is following to meet those requirements. 

Chapter 2 provides background on the existing non-microbial regulations, including the dates of 

promulgation. Chapter 3 provides a description of technologies that can be used to treat more than 

one group of contaminants. Technologies that only apply to one group of contaminants are 

described in the chapter devoted to that contaminant group. Chapter 4 summarizesthe national-level 

affordability criteria and describes when and how these criteria were used to identify affordable 

compliance technologies. Chapter 5 describes the compliance technologies for each of the IOCs, * 

including corrosion by-products. Chapter 6 describes the compliance technologies for each of the 

radionuclides. Chapter 7 describes the compliance technologies for each of the VOCs. Chapter 8 

describes the compliance technologies for each of the SOCs. 
References 

Congressional Record. 1974. House of Representatives 93-1 185 at 18. The 93rd Congress, Second 

Session. 13. Microfilm #H503-28. , 

Congressional Record. 1986. Vol. 132. 99th Congress, Second Session. No. 69. May 2 1,1986. 

P. S6287. Statement of Senator Durenberger. [132 Cong. Reg.] 

USEPA. “Four Documents Required Under the .Safe Drinking Water Act as Amended”. Federal 

Register. 62( 154): 42986. August 1 1,1997. (EPA 1997a). 

USEPA. “Small System Compliance Technology List for the Surface Water Treatment Rule”. 

EPA-8 15-R-97-002. Office of Water. August 1997. (EPA 1997b). 

USEPA. “Announcement of Small Systems Compliance Technolegy Lists for Existing National 

Primary Drinking Water Regulations and Findings Concerning Variance Technologies”. Federal 

Register. 63( 151): 42032. August 6. 1998. (EPA 1998a). 

USEPA. “Small System Compliance Technology List for the Surface Water Treatment Rule and 

Total Coliform Rule”. EPA-8 I S-R-98-00 1. Office of Water. September 1998. (EPA 1998b). 

USEPA. “Variance Technolog! Findings for Contaminants Regulated before 1996”. EPA 815-R98-003. Office of Water. Scptcmkr 1998. (EPA 1998~). 

USEPA. “Revision of fiximng \’xiance and Exemption Regulations To Comply With 

Requirements of the Safe 1)rinLing U ater Act; Final Rule”. Federal Register. 63( 157): 43834. 

August 14, 1998. (EPA IQWd) 

USEPA. “Information for Sutc\ on I)c\doping Affordability Criteria for Drinking Water”. EPA816-R-98-002. Office of M’rrtcr 1 chary, 1998. (EPA 1998e). 

USEPA. “National-Level Atf~rdahliryCriteria Under the 1996 Amendments to the Safe Drinking 

Water Act”. Prepared by International Consultants, Inc., Hagler Bailly Services, Inc. and Janice A. 

Beecher, Ph.D. for the EPA. August 1998. (EPA 19980). -

USEPA. “Removal of the Prohibition on the Use of Point of Use for Compliance with National 

Primary Drinking Water Regulations“. Federal Register. 63( 112): 31932. June 11,1998. (EPA 

19988). 

USEPA. “Cost Evaluation of Small System Compliance Options: Point-of-Use and Point-of-Entry 

Treatment Units”. Prepared by The Cadmus Group, Inc. September 1998. (EPA 1998h). 

l 
2. BACKGROUND ON EXISTING NATIONAL PRIMARY DRINKING WATER 

REGULATIONS 

This chapter discusses the regulatory history that has resulted in the existing drinking water 

regulations. The discussion is meant to briefly describe the relevant parts of the charge given to EPA 

by the 1974 Safe Drinking Water Act (SDWA) and its 1986 Amendments and to briefly explain the 

evolution of the National Primary Drinking Water Regulations (NPDWRs) that were promulgated 

in response. It is not meant to be a detailed explanation or history of these events, but rather is 

intended to provide the reader with enough information regarding the NPDW so that he or she will 

know which NPDWR is associated with a particular contaminant. It also meant as a catalogue of 

the Federal Register citations of the various NPDWRs. 

* 

-

Through the SDWA, Congress requires EPA to regulate contaminants which present health 

risks and which are known to occur in some public drinking water supplies. Under the current 

SDWA, EPA sets legal limits on the levels of certain contaminants in drinking water through 

Maximum Contaminant Levels (MCLs) and treatment techniques. The legal limits are as protective 

of human health as is “feasible”, where feasibility is determined by treatment removal efficiencies 

using the best available technologies, the levels of the contaminant found in drinking water sources 

and other water quality parameters, and the levels at which the contaminant can be accurately 

quantified analytically. In cases where available analytical methods are inadequate or normal 

monitoring schemes are inadequate, EPA may impose treatment techniques to be followed under 

specified conditions. For rules that involve MCLs, “best available technologies” for treating 

contaminated water and analytical methods are listed. SDWA gives individual states the opportunity 

to set and enforce their own drinking water standards as long as the standards are at least as stringent 

as EPA’s national standards. Most states and territories directly oversee the regulatory programs for 

water systems within their borders. 

The United States Congress enacted the Safe Drinking Water Act (SDWA) on December 16, 

1974 (Public Law 93-523). In response to SDWA. EPA regulated 23 contaminants between 1975 

and 1985. The 1974 SDWA called for EPA to regulate drinking water contaminants in two steps. 

The first step involved the creation of the National Interim Primary Drinking Water Regulations 

(NIPDWRs), based largely on the 1962 US.Public Health Service standards. The second step 

involved the revision of these standards, as deemed necessary, following a comprehensive review 

by the National Academy of Sciences of the risks posed to water consumers from the regulated 

contaminants. The NIPDWRs were fully enforceable after their respective stated “effective dates”. 

The first NIPDWRs were promulgated in 1975, the Radionuclides NIPDWRs in 1976, the 

Trihalomethanes NIPDWRs in 1979, and the Fluoride Rule in 1986, ‘shortly before the 1986 

Amendments. .. 

-

Congress amended SDWA on June 19, 1986 (Public Law 99-339). The 1986 Amendments 

required EPA to set Maximum Contaminant Level Goals (MCLGs) and National Primary Drinking 

Water Regulations (NPDWRs) for 83 specific contaminants. The Amendments declared that the 

existing NIPDWRs were finalized as NPDWRs upon enactment of the 1986 SDWA. included 
provisions for periodic review of the data and studies affecting the basis of the MCLGs and MCLs, 

and made provisions for allowing variances under specified conditions. 

The list of 83 contaminants included 22 with NIPDWRs (excluded total trihalomethanes) and 

remainder were new contaminants. The amendments also required EPA to regulate 25 additional 

contaminants every three years, effective January of 1991 and continuing indefinitely. In addition, 

each NPDWR was to be reviewed triennially to ensure the continued adequacy of the MCLG and 

MCL. In 1987, EPA exercised discretion provided by SDWA in substituting ethylbenzene, styrene, 

heptachlor, heptachlor epoxide, nitrite, aldicarb sulfoxide, and aldicarb sulfone for 7 of the 83 

contaminants listed for regulation. EPA chose to regulate the 83 contaminants in phases, according 

to the availability of data and studies supporting the setting of MCLGs and NPDWRs. The Phase 

I Rule, otherwise known as the VOCAJnregulated Contaminants Rule, was promulgated in 1987, 

the Phase I1 Rule, the Lead and Copper Rule, and the Phase 11-b Rule in 1991, and the Phase V Rule 

in 1992. The Phase I11 Rule became known as the Radionuclides Rule and is currently being 

reviewed. The Phase IV Rule became known as the Disinfection-By-Products Rule, which is due 

to be promulgated in November of 1998. All of the relevant rules are discussed in more detail 

below. 

Congress again amended SDWA on August 6,1996. The 1996 Amendments resulted in several 

provisions related to the Small Systems Compliance Technology Lists, as discussed in the first 

chapter. However. the Small Systems Compliance Technology List deadline covered by this 

document applies only to the pre-1996 regulated contaminants, so the impact of the 1996 SDWA 

on future rules and updates need not be discussed here. 

Section 2.1 National Interim Primary Drinking Water Regulations (NIPDWRs) (40 59566) 

The National Interim Primary Drinking Water Regulations (NIPDWRs) were promulgated on 

December 24, 1975. This rule established Maximum Contaminant Levels (MCLs) for 6 synthetic 

organic contaminants, 10 inorganic contaminants, turbidity, and total coliform. The rule also 

established requirements for monitoring. analytical methods, reporting, record keeping, and public 

notification for each of the contaminants. The MCLs established by this rule were designed to be 

enforceable until revised. 

Section 2.2: Radionuclides NIPDWRs (41 FR 28402) -

The Radionuclides NIPDWRs were promulgated on July 9, 1976. This rule established MCLs 

for combined radium-226 and -228 and two classes of radionuclide contaminants. It also established 

requirements for monitoring, analytical methods, reporting, and record keeping for these 

contaminants. The MCLs established by this rule were designed to be enforceable until revised. The 

MCLs established by this rule are currently in effect, although the rule is being reviewed at the time 

of this writing. 

i 

I 
Section 2.3: Trihalomethanes NIPDWRs (44FR 68624) 

The Trihalomethanes NIPDWRs were promulgated on November 29, 1979. This rule 

established MCLs and requirements for monitoring, analytical methods, and reporting for total 

trihalomethanes. “Total trihalomethanes” is defined as the summed concentrations of the four 

trihalomethane chemicals defined in the rule. This rule only applies to community water systems 

serving 10,000 persons or more that add a chemical disinfectant during any part of the dnnking water 

treatment process. Since this rule does not apply to small drinking water systems, total 

trihalomethanes will not be considered in terms of small systems compliance or variance 

technologies. 

Section 2.4: Fluoride Rule (51 r;R 11396) 

The Fluoride Rule was promulgated on April 2, 1986, updating the Fluoride NIPDWR, which 

was included in the 1975NIPDWRs. This rule established an MCL md secondary MCL for fluoride 

and applies only to community water systems. The rule also established a. procedure by which 

public water systems could obtain variances from the interim and revised regulations for fluoride. 

The variance procedure includes the identification and installation of best available technology 

(BAT) for fluoride removal. EPA later revised the monitoring requirements (EPA 1995b) for 

fluoride by including it into the Standardized Monitoring Framework promulgated under the Phase 

I1 Rule (January 30, 1991). 

Section 2.5: Phase I Rule (52 25690) 

The Phase I Rule was promulgated on July 8, 1987. This rule establishes MCLs and 

requirements for monitoring, reporting, and public notification for 8 volatile organic contaminants 

(VOCs). The rule also establishes monitoring requirements for 51 other synthetic organic 

contaminants not regulated by NPDWRs, ;.e., unregulated contaminant monitoring. The rule applies 

to community water systems and non-transient, non-community water systems. 

Section 2.6: Phase I1 Rule (56 FR 3526) and Phase II-b Rule (56 FR 30266) 

The combined Phase I1 Rule was promulgated in two rule makings, the “Phase I1 Rule’’ on 

January 30, 1991 and the “Phase IIb Rule” on July 1, 1991. Combined, the two rule makings 

establish new requirements for the regulation of 38 chemicals, 1 1 of which were previously regulated 

under the 1975 NIPDWRs, including barium, cadmium, chromium, mercury, nitrate, selenium. 2,4-

D, lindane, methoxychlor, toxaphene, and 2,4,5-TP. Additionally, the Phase I1 Rule removed silver 

from the list of NPDWRs and developed SMCLs for silver and aluminum. 

The Phase I1 Rule (January 30, 1991) establishes Maximum Contaminant Level Goals 

(MCLGs), MCLs, and requirements for monitoring, analytical methods, and public notification for 

26 synthetic and volatile organic contaminants (SOCs, VOCs) and 7 inorganic Contaminants(IOCs). 

The rule also reproposes MCLs for 5 contaminants. Some of the regulations apply to all public 
I -

. 

water supplies and others only to community water systems and non-transient, non-community water 

systems. 

The Phase IIb Rule finalizes the MCLGs and NPDWRs for the 5 contaminants reproposed in 

the Phase I1 Rule. It also changes the monitoring requirements to the standardized monitoring 

framework for the 8 VOCs regulated in the Phase I Rule. 

Two contaminants regulated by the Phase I1 Rule, acrylamide and epichlorohydrin, are not 

applicable to the determination of small system compliance technology lists or small system 

variances. These two compounds are associated with chemical additives used in drinking water 

treatment and are regulated through a treatment technique that requires a certification that the 

product of the dose and monomer concentration will not exceed certain levels. No treatment 

technology is required to be installed to reduce contaminant levels under this treatment technique. 

As such, there are no compliance or variance technologiesfor either acrylamide or epichlorohydrin. 

On May 27,1992 EPA postponed the effective date of the MCLs and amended the monitoring 

requirements for aldicarb, aldicarb sulfone, and aldicarb sulfoxide (56 FR 221778). This stay will 

remain in effect while EPA conducts a revised risk assessment and solicits public comment on the 

risk assessments. During this time, these pesticides are being monitored as unregulated 

contaminants. 

Section 2.7: Lead and Copper Rule (56 FR 26460) 

The Lead and Copper Rule was promulgated on June 7, 1991 and became effective on 

December 7, 1992. This rule establishes MCLGs and NPDWRs for controlling lead and copper 

levels in drinking water. Although all rules establishing treatment techniques are unique, the Lead 

and Copper Rule stands out because it is the only NPDWR that attempts to minimize contamination 

introduced by the action of the water itself on the distribution system. Other treatment techniques 

either address contaminants in the source water (e.g., the Surface Water Treatment Rule) or 

contaminants that may result from the treatment processes themselves (e.g., NPDWR for 

epichlorohydrin). 

Lead and copper contamination of drinking water mainly occurs after the water is in the 

distribution system, so monitoring at the treatment plant is not adequate. The contamination results 

from corrosion of pipes and plumbing in the distribution system. The Lead and Copper Rule 

requires community water systems and non-transient, non-community water systems to complete 

a materials evaluation of their distribution system and/or review other information to target homes 

that are at high risk of lead and copper contamination. Water systems are required to monitor at the 

tap in these high risk homes, with the number of tap-sampling sites being proportional to the 
-- 

population served. Those systems with lead levels above the action level' are required to apply a 

treatment technique for mitigation, that may include corrosion control treatment, source water 

treatment, lead service line replacement, and public education. Replacement of lead containing 

materials within a distribution system is only required if corrosion control measures do not bring 

lead levels below the action level. Systems with elevated copper levels should apply corrosion 

control treatment, since replacement of the copper piping source material is generally cost 

prohibitive. 

Section 2.8: Phase V Rule (57 FR 31776) 

The Phase V Rule established MCLGs and promulgated NPDWRs for 18 synthetic organic 

contaminants and 5 inorganic contaminants. The monitoring framework for these contaminants are 

in the standardized monitoring framework format. This rule applies to community water systems 

and non-transient, non-community water systems. The NPDWR for nickel was revoked. 

Section 2.9: Summary of National Primary Drinking Water Regulations (NPDWRs) 

Table 2.1 1 tabulates the various regulated drinking water contaminants, providing information 

on contaminant type, the governing NPDWR, and the promulgated MCLs and BATs. For more 

information on the NPD\J'Ks. visit the Office of Ground Water and Drinking Water's Internet 

hom epage (http://w\+u .cpa.go\ OG\TI W). The homepage has a table 

(http://www.epa.gov/OG~'I)~~' unt appa.html) of current NPDWRs that includes information on 

health effects from ingestion ot the regulated contaminants and the sources responsible for their 

occurrence in drinking \vatu 1 unhcr information on the drinking water regulatory history can be 

found on the OGWDQ' homcpagt. at "http://www.epa.gov/safewater/source/theruIe.htrnI".Each of 

the BATs is discussed in later chqtcrh 

~ ~

I Summar! of C urrcnt \sttonal Primary Drinking Water Regulations (NPDWRs) I 

Contaminant 

Benzene 

l!pc NPDWR BATs MCL 

OlgW 

1 ( K Phase I Rule GAC, PTA 5 -~- ~~~~ ~- ~ 

Carbon Tetrachloride \'OC 

Chlorobenzene VOC 

cis- I,? Dichlorobenzene VOC 

Dibromochloropropane voc 

I .1-Dichloroethane voc 

Phase 1 Rule GAC, PTA 5 

Phase I1 Rule GAC, PTA 100 " 

Phase I1 Rule GAC, PTA 7 

Phase 11 Rule GAC, PTA 0.2 

Phase I Rule GAC, PTA 5 

I Action levels are different from MCLs in that, rather than being a legal limit on a 

cmtaminant like an MCL, they are triggers for taking prescriptive prevention or removal steps. 

6 
T I Styrene 

I Tetrachloroethylene (PCE) 

I Toluene 

I trans- 1,2-Dichloroethylene 

I 1,2,4- Trichlorobenzene 

1, 1,I - Trichloroethane 

1,1.2- Trichloroethane 

Trichloroethylene (TCE) 

Vinyl Chloride 

1 Xylenes (total) 

I Alachlor 

I Atrazine 

I Carbofuran 

Chlordane 

Dibrornochloropropane 

2.4-D 

Ethylene Dibrornide ~-

Heptachlor 

Heptachlor Epoxide 

I Lindane 

Methoxychlor 

I Polychlorinated Biphenyls 

I VOC I Phase I1 Rule I GAC, PTA I 100 I

I VOC I Phase I1 Rule GAC, PTA I 5 

I VOC I Phase I1 Rule GAC, PTA I 1000 

I VOC I Phase I1 Rule GAC, PTA 100 

1 VOC I Phase V Rule GAC, PTA 70 

VOC Phase I Rule GAC, PTA 200 

voc Phase V Rule GAC, PTA 5 

VoC Phase I Rule GAC, PTA 5 

\‘Oc Phase 1 Rule GAC. PTA 2 

I I I 

GAC. PTA ~ ~ 7-,Goo

1 ioc I Phase I1 Rule GAC 

1 2 

1 \( Y I Phase 11 Rule GAC 

1 3 

I st Y I Phase 11 Rule GAC I 40 

\( y‘ Phase I1 Rule GAC 2 

trc y‘ Phase I1 Rule GAC, PTA 0.2 

5OC Phase I1 Rule GAC 70 

soc Phase 11 Rule GAC, PTA 0.05 

I SOC 

Phase I1 Rule 

Phase I1 Rule 

GAC 

1 GAC 

0.4 

I SOC Phase Ii Rule I GAC 

SOC Phase 11 Rule GAC 40 

I SOC Phase I1 Rule [ GAC I 0.5 
Pentachlorophenol 

Toxaphene 

2,4,5-TP 

Benzo(a)pyrene 

Dalapon 

Di(2-ethylhexyl) adipate 

Di(2-ethylhexyl) phthalate 

Dinoseb 

Diquat 

Endothall 

Endrin 

Glyphosate 

Hexachlorobenzene 

Hexachlorocyclopentadiene 

Oxamyl 

Picloram 

Simazine 

2,3,7,8-TCDD (Dioxin) 

Acrylamide 

Epichlorohydrin 

Antimony 

Asbestos 

Cyanide 

Lead 

Arsenic 

Barium 

SOC Phase I1 Rule 

SOC Phase 11 Rule 

SOC Phase I1 Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase V Rule 

SOC Phase I1 Rule ~ 

sac Phase I1 Rule ~~ ~ 

I oc Phase V Rule 

IOC Phase I1 Rule 

IOC Phase V Rule 

GAC 1 

GAC 3 

GAC 50 

GAC 0.2 

GAC 200 

GAC, PTA 400 

GAC 6 

GAC 7 

GAC 20 

GAC 100 

GAC 2 ~~ I oxidation (Cli or 0,)- I 700 

I GAC 1 

I GAC, PTA I 50 

, GAC I 200 

GAC 

GAC 

GAC 

treatment technique 

treatment technique 

500 

4 

3 10-5 

TT 

TT 

CF, RO 

CF, Corrosion Control, 7 million 

Direct Filt, Diatom Filt fibers/liter 

(longer than 

10 Pm) 

IX, RO, alkaline CI, 200 

TT 

50 

2000 

IOC Lead and Copper, 

Final Rule 

NIPDWR for 

arsenic 

Phase I1 Rule 

treatment technique 

CF, LS, IX, RO, EDR 

IX, LS, RO, EDR 
Beryllium I IOC 

Cadmium IOC 

Chromium 1oc 

Copper IOC 

Fluoride I oc 

Mercury IOC 

Nitrate I IOC 

Nitrite I IOC 

Nitrate + Nitrite I 1OC 

Selenium 

Thallium 

combined radium-226 and radium228 

gross alpha particle activity 

total beta particle activity and 

photon activity 

I oc 

IOC 

RAD 

RAD 

RAD 

I Phase V Rule 

Phase 11 Rule 

Phase I1 Rule 

Lead and Copper, 

Final Rule 

Fluoride, Final 

Rule 

Phase 11 Rule I Phase 11 Rule 

Phase 11 Rule 

I Phase 11 Rule 

Phase II Rule 

Phase V Rule 

Radionuclides 

Rule 

Radionuclides 

Rule 

Radionuclides 

Rule 

~ ~ 

I AA, CF, LS, IX, RO I 4 

CF, IX, LS, RO 5 

CF, IX, LS, RO 100 

treatment technique TT 

AA, RO 4000 

CF, GAC, LS, RO 2 

I IX7 Ro, EDR 

IX, RO 

- See individual 

contaminants -

AA, CF, IX, LS, RO, 50 

EDR I 

AA, IX 2 

IX, LS, RO 5 pCi/L 

RO 15 pCi/L 

IX, RO' 4 mrem/yr 

~ ~ ~ ~ ~~~ 

Notes: GAC = granular activated carbon. PTA = packed tower aeration, IX = ion exchange, LS = lime softening, 

RO = reverse osmosis, CF = coagulation filtration. EDR = electrodialysis/electrodialysisreversal, AA = activated 

alumina. 

I -
3. DESCRIPTIONS OF TREATMENT TECHNOLOGIES FOR SMALL SYSTEMS 

This chapter discusses small systems treatment technologies that can be used for the removal 

of more than one class of the currently regulated drinking water contaminants. Each process is 

briefly described and issues specific to small systems needs are highlighted. Advantages, 

limitations, and special considerations are emphasized where applicable. Small systems treatment 

strategies include centralized treatment, including package plants, and point-of-use/entry (POUE) 

technologies. Each strategy is discussed in general, then individual technologies are discussed. The 

choice of strategy to be used in a specific situation depends on the source water quality, the nature 

of the contaminant to be removed, the desired qualities of the finished water, and the size of the 

drinking water system. -

Centralized Treatment 

For small systems, centralized treatment refers to both full scaleconventional treatment and to 

centrally located package plant treatment. This section will focus on full scale conventional 

treatment; package plants are discussed below. Centralized treatment refers to the practice of 

treating water at a centralized location before it enters the distribution system. Centralized treatment 

at more than one entry point is sometimes referred to as “de-centralized treatment”. This point is 

important because it clarifies the differentiation between multiple entry point centralized treatment 

and POUE treatment. Within this document, “centralized treatment” will include both single entry 

point centralized treatment and multiple entry point treatment. 

In general, centralized treatment is preferred to POU/E technologies since monitoring and 

maintenance can be centrally managed, which is the most reliable way to ensure safe water. Full 

scale conventional treatwent is the most common strategy for systems serving more than a few 

thousand persons (EPA 1993, p. 97). Full scale treatment is designed by a consulting engineer and 

makes use of originally designed and fabricated concrete and steel structures, as opposed to prefabricated package plant units. Larger systems can pass the higher engineering and construction 

costs through the large customer base at a generally reasonable per user cost. The costs associated 

with fully engineered treatment technologies can be prohibitive for the smallest of water systems, 

but for some technologies, e.g., packed tower aeration, full scale treatment may be cost-effective 

down to very small system sizes. 

Packape Plant Treatment 

Package plants are skid mounted factory assembled centralized treatment units that arrive on 

site “virtually ready to use” (Goodrich et al. 1992, EPA 1993). Package plants offer several 

advantages. First, since they combine elements of the treatment process into a compact assembly 

(such as chemical feeders, mixers, flocculators, basins, and filters), they tend to require lesser 

construction and engineering costs. Another advantage is that many package plant technologies are 

becoming more automated and thus can be less demanding of operators than their fully engineered 

counter-parts (EPA 1990). However, pilot testing requirements can significantly increase package 
treatment costs. Some states require pilot tests of all package plant installations. Often package 

plant pilot testing is required on a case by case basis, so that results from one situation can not be 

‘-transferred”to another situation, regardless of how similar the situations may be. Since pilot testing 

is resource intensive and can last from several weeks to a year or more, it can add significant costs, 

e.g., more than thirty percent to the original equipment costs in some cases (Goodrich et al. 1992). 

Since it is, of course, essential to confirm that installed treatment is working properly, the need for 

site specific pilot testing can not be entirely eliminated, but it can be reduced (EPA 1993). To this 

end, verification of package plant performance by an independent party would reduce costs by 

reducing in degree the need for pilot testing. It is important to keep in mind that pilot testing needs 

are specific both to the technology in question and to source water quality. For a discussion of pilot 

testing needs for individual technologies, see, e.g., NRC’s Safe Water from Every Tap (NRC 1997). 

This need for package plant performance verification is currently being addressed by EPA in 

cooperation with National Sanitation Foundation (NSF) International through an EPA 

Environmental Technology Verification project. Together they are cooperatively organizing and 

developing a pilot project (Package Drinking Water Treatment Systems Pilot Project) to allow for 

verification testing of package plant units. The aims of the project include developing verification 

testing protocols and test plans, independently testing and validating package plant equipment, 

conveying and supporting governmentlindustry partnerships to obtain credible cost and treatment 

performance data, and preparing product verification reports for public use. It is expected that the 

program will become financially self-sustaining through user fees and leveraged resources. More 

information regarding this program may be found on the NSF Internet website at 

“http://www.nsf.org/verification/html/oven4ew. html”. 

Whether or not a small system can afford a package plant technology is only part of the 

question. In addition, the system must have an operator or contractor who can properly operate and 

maintain the equipment. Fortunately, many package plant technologies are becoming more 

automated and simpler to use. For example, modem filtration membrane technologies have the 

ability to backwash automatically. greatly simplifying their use. In cases where a technology 

requires more advanced skills, recent advances (NRC 1997) in telemetry devices or remote 

monitoring and control devices have made it possible for a single operator to monitor and operate 

several small water systems within a given area. These “circuit rider” operators can work from a 

central location while receiving information (including alarms) from the various plants via FAX or 

modem. Remote control capabilities allow the circuit rider operator to control certain aspects of the 

treatment process (e.g., chemical coagulant dosage or disinfection dosage) via a modem or other 

means. This reduces operator costs to a single system and can reduce the amounts of chemicals 

required for treatment. These telemetric devices may make those technologies requiring a full-time 

operator more feasible for many small systems. The combined use of package plants and telemetric 

monitoring and control may well extend many of the more complex water treatment technologies 

to the universe of technologies appropriate for small systems. 
Point-of-Use/ Point-of-Entrv Technologies 

Point-of-entry (POE) treatment units (Goodrich et al. 1992, Lykins et al. 1992) treat all of the 

water entering a household or other building, with the result being treated water from any tap. Pointof-use (POU) treatment units treat only the water at a particular tap or faucet, with the result being 

treated water that one tap. with the other taps serving untreated water. POE and POU treatment units 

often use the same technological concepts employed in the analogous central treatment processes, 

the main difference being the much smaller scale of the device itself and the flows being treated. 

Sometimes the POEAJ technology uses essentially the same process as its full-scale counterpart, but 

in some instances process modifications are required to account for the much smaller flows being 

treated. For example, full-scale filtration technologies often use periodic backwashings to extend 

the lifetime of the filter bed. whereas POU filtration technologies are often used until exhausted and 

then simply discarded. 

POEAJ devices have disadvantages to their use and so are-generally used only when a 

centralized treatment facilit). is not technically or financially feasible for a water system. Regarding 

POU devices, if one is placed under the kitchen sink to treat food for drinking and cooking, only that 

water is potable; water from a bathroom tap would be untreated, and thus exposure to contaminants 

during teeth brushing. etc. is possible (NRC 1997). In some cases, POU technologies are simply not 

applicable, e.g., in cases of \alrrrile contaminants which would volatilize into the indoor air during 

showering and other warcr uws In these cases, only POE treatment or centralized treatment is 

appropriate. POE treatmcnr unitc also have limitations. For example, some POE filters require 

backwashing or regeneration nuinrain a reasonable filter bedresin lifetime (number of bed 

volumes before the filter hd or rwn nccds replacement). If the backwash requires special disposal 

methods, costs may incrcau' prthihiti\cI>~.In the case of acute contaminants, which can cause 

adverse health effects aftcr shon ism exposures, POEAJ treatment is generally not viewed as 

appropriate (NRC 1997) f or cumplc. thc 1998 Small Systems Compliance Technologies Lists for 

the Surface Water Treatmcn! Ruk mJ the Total Coliform Rule (EPA 1998a) does not list any 

POE/U devices for the rnicn1hi.L conraniinants or microbial indicators. The legal requirements for 

the use of POE/U devices a5 complimcc technologies are discussed in Section 1.4. 

Technologies that arc amcnhlc to POEAJ scale treatment include activated alumina, granular 

activated carbon. reverse osniosi\ ion exchange, and air stripping. Each of these applications is 

discussed below along uith its ccntrdized treatment analogue. There are also discussions of POEU 

technologies in the chapters dcrtling \vith compliance technologies for specific contaminants. 

Before installing POEk!' treatment units. water systems should evaluate the units for treatment 

efficacy and efficiency. For devices that employ cartridges (e.g.. GAC and activated alumina), the 

NRC (1997) recommends that water systems pilot test to develop estimates of the unit's service life 

for their particular source water. In other cases, evaluations may be simpler, e.g., for RO it may only 

be necessary to confirm that membrane fouling will not be a problem. These concerns are discussed 

in more detail in the individual technologies discussions below. 

. 
-- 

Effective operation. monitoring, and maintenance are vital to the successful use of POEN 

treatment units for compliance purposes (Goodrich et al. 1992, NRC 1997). As discussed in Section 

1.4, the units are required by the SDWA to 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 MCL or treatment technique and equipped with 

mechanical warnings to ensure that customers are automatically notified of operational problems”. 

Proper installation is of course essential. After installation, the PWS needs a well-defined operation 

and maintenance program to assure a continuous supply of safe drinking water. The PWS also needs 

a routine monitoring program to confirm that the operation and maintenance program is adequate 

and that the treated water meets drinking water standards. 

Specific Technoloyies 

Specific technologies that apply to more than a single class of chemical contaminants are 

discussed below. 

Activated Alumina 

Activated Alumina (AA) is a physical and chemical process in which ions in the feed water are 

sorbed to an oxidized AA surface. AA is prepared through dehydration of A1(OH)3 at high 

temperatures and consists of amorphous and gamma alumina oxide. AA is used in packed beds to 

remove contaminants such as fluoride, arsenic, selenium, silica, and natural organic matter. Feed 

water is continuously passed through the bed to remove contaminants. The contaminant ions are 

exchanged with the surface hydroxides on the alumina. The adsorption ability of AA media must 

eventually be replenished. When all adsorption sites on the AA surface are filled, the bed must be 

regenerated. Regeneration is accomplished through a sequence of rinsing with regenerant, flushing 

with water, and neutralizing with acid. -Theregenerant is a strong base, typically sodium hydroxide; 

the neutralizer is a strong acid, typically sulfuric acid (EPA 1998b). The alumina dissolves slightly 

in sodium hydroxide. Over time the media will dissolve and require replacement. 

AA is useful for removing negatively charged ions. AA displays amphoteric properties, 

meaning its surface charge changes with solution pH. AA is not charged at a pH of 9.5, is positively 

charged below this pH, and is negatively charged above it (NRC 1997). Anions are best adsorbed 

below this pH. 

Water quality strongly influences the residence times and flow rates necessary for proper 

operation of activated alumina columns. In particular, the potential for preferential exchange of 

anions other than the target compounds in the raw water must be evaluated for each source water that 

will be treated with AA (NRC 1997). 

As with ion exchange, regenerant disposal can be a problem. Some facilities discharge the 

regenerant brine solution to lined evaporation ponds designed for this purpose. After the water 

evaporates from the salts, the dried salts are disposed of in a landfill. Disposal costs can make up 

6 

aq 
much of the operating cost of this technology. 

AA may be well suited for small systems. The columns can be scaled and more added if 

necessary. Small systems should be concerned, however, about cost and operational complexity 

(NRC 1997). For instance, small systems should be concerned about the chemicals that may be 

required to operate AA. Stakeholders agreed that small systems would not likely regenerate on sight. 

Regenerating the media off-site or disposing of the spent media may be possibilities. Small systems 

should also be concerned about highly concentrated waste streams. 

Activated Carbon 

Activated carbon is similar to charcoal in composition, but is surfacially altered to enhance its 

sorption properties. The base carbon material (typically bituminous coat, lignite, petroleum coke, 

or bone char) is carbonized through heating it in the absence of air and then activated by oxidation 

at high temperature (200°C to 1000°C). The activation process results in a highly porous, high 

surface area per unit mass material with a large sorption capacity for many water impurities, 

including synthetic organic contaminants ( SOCs), taste and odor causing compounds, and some 

species of mercury. (Snoeyink 1990. NRC 1997. AWWA - ASCE 1998). 

Granular activated carbon (GAC) 

GAC treatment removes contaminants iia the physical and chemical process of sorption, by 

which the contaminants accumulate at thc carbon surface as the water passes through the carbon bed. 

Removal efficiencies for many organic contaminants are excellent under ideal circumstances, but 

can be significantly affected by nimr quaiif!. parameters, like dissolved natural organic matter 

levels, pH, and temperature. Remo\al ctficicncies change drastically once the bed nears exhaustion. 

At exhaustion, contaminant breakthrough occurs. which is often defined as the point in time when 

the contaminant concentration in thc ctflucnt equals that in the influent. Before this occurs, the 

carbon bed must be regenerated or rcplaccd to ensure proper removals (Snoeyink 1990). 

Information regarding GAC contactor contigurations, operational modes, and design factors can 

be found in many sources (e.g.. AL\'\\'.+I 1990. EPA 1990, Snoeyink 1990, AWWA - ASCE 1998). 

Operating problems encountered \\.hen using activated carbon are similar to those associated with 

rapid sand and dual-media filters. Common operating problems include: controlling the carbon 

depth, (when applicable) ensuring propcr back\vashing and maintaining depth and bed density after 

backwashing, removing carbon from the contactors and storage tanks, regenzrating the carbon. 

controlling contactor flow rate, and controlling biological growth in the carbon bed (AWWA - ASCE 

1998). 

GAC often requires pre-filteration to remove particulate matter fiom the source water to prevent 

clogging of the GAC bed. An alternative is to use the GAC column itself as a filter medium, 

performing both filtration and sorption simultaneously. The disadvantage of this latter approach is 

that fiequent backwashing of the column is required. Backwashng may cause spent carbon to come 
into contact with the treated water: if this can be tolerated, then the technology is straightfonvard 

and compact (NRC 1997). 

Competitive sorption can also significantly affect the removal efficiency of an activated carbon 

system. Naturally occurring dissolved organic matter may compete with organic contaminants for 

GAC sorption sites, decreasing the removal efficiency for a given GAC column and thus increasing 

the amount of GAC needed to achieve the optimal efficiency. Competing organic compounds can 

also displace (cause the desorption of) contaminants. If influent water quality changes result in a 

high concentration of the competing compound. the contaminant desorption process may temporarily 

cause the contaminant level in the effluent to exceed that in the influent. Because of this,competing 

chemicals need to be removed from the water prior to GAC treatment, or the GAC system should 

be designed to accommodate the fluctuation in concentrations of the competing compounds 

(Snoeyink 1990). 

Single-stage GAC systems (in which all of the water being treated flows through one column, 

rather than through two or more in series) must be monitored to ensure that breakthrough does not 

occur. If an exhausted GAC column is not regenerated or replaced, desorption may result in the 

effluent having higher concentrations of the contaminant than the untreated water. Monitoring for 

some organic compounds may require an advanced operator or the services of an outside laboratory. 

In general, GAC is straightfonvard to appl!. on a small scale. Small columns may be easily obtained 

and installed. If virgin carbon is required (Lvhichcan be the case with drinking water applications), 

the operating costs are often higher. 

Powdered activated carbon {PAC) 

Powdered activated carbon (PAC ) treatment works in much the same way as GAC. The main 

difference is the mode of application and the grain size of the activated carbon. PAC grains are ten 

to one hundred times smaller than GAC grains. but the water being treated comes into contact with 

much less carbon material per unit volume treated. so the process is not as efficient as GAC. The 

carbon powder is added directly to the raw user line or to a mixing basin. For efficient removals, 

all of the water being treated should comc into contact with the carbon. The sorption process is very 

quick because of the small carbon panicle size (which increases the specific surface area of the 

activated carbon) and thus the normal mising basin contact times used for other elements of the 

treatment train are sufficient for sorption. In such cases. no modifications to the existing structure 

of the treatment plant need be madc. Testing prior to design determines the required contact time. 

After proper contact. the PAC is scttled or filtered from the water and disposed of with the plant 

I - sludge. Proper removal of the PAC after sorption is required to ensure contaminant removal and to 

prevent discoloration of the effluent (KRC 1997). The same argument concerning competitive 

sorption for GAC treatment applies to P.4C treatment. 

PAC can be very economical if required only periodically (e.g., seasonally) in response to 

changes in water quality. If the dose can be optimized and adjusted in response to variations in 

influent water quality, then further savings can be incurred. In general, PAC is simple to employ on 
a small scale if the plant already has a treatment train in place that includes mixing, precipitation or 

sedimentation. and filtration. 

PAC may adsorb some chemicals that are added during the treatment process, e.g., chlorine and 

potassium permanganate. For this and other reasons, the best point of application is usually at the 

head of plant, either in the source water pipeline or in a mixing basin (AWWA - ASCE 1998). 

Air Strippiny (Aeration) 

Air stripping, or aeration, involves the continuous contact of air with the water being treated, 

allowing volatile dissolved contaminants to transfer from the source water to the air. After contact, 

the “contaminated air” is swept from the system, taking the contaminants, e.g., volatile organic 

chemicals, taste- and odor- causing compounds, and radon, out of contact with the treated water. 

The driving force for the water-to-air transfer of the volatile contaminants is related to the 

contaminant concentration gradient between the water and air. In designing aeration treatment, it 

is important to consider both the total amount of transfer possible, Le., the amount that would be 

transferred to reach equilibrium, and the rate at which transfer takes place. The amount of possible 

transfer is dependent on a combination of the physiochemical characteristics of the contaminant 

(such as molecular weight, molecular charge/polarity and shape, etc., all of which also affect the 

water solubility), site specific conditions. like temperature and water quality, and the design of the 

aeration system. e.g., aidwater ratio. The Henry’s Law coefficient is a commonly used indicator of 

the tendency of a contaminant to partition from water to air. A large value (by common definitions’) 

indicates that the contaminant can be significantly stripped from water. Efficient stripping is also 

a function of the rate of transfer, which depends on both the properties of the contaminant, the site 

specific conditions, and the aeration design. e.g., an effective contact surface area between the air 

and water (Cornwell 1990). 

The key factors which are considered in the design of aeration systems include contact time 

(time of exposure); air-to-water ratio; proper dispersal of waste gases into atmosphere; physical 

chemistry of the contaminant; influent concentration of the contaminant; water and surrounding air 

temperatures (AWWA and ASCE 1998). The most common types of aeration systems include 

packed tower aerators. diffuser aerators. including multi-stage bubble aerators, multi- or shallow tray 

aerators, spray aerators, mechanical aerators. and gas permeable membrane aerators. 

The Henry’s Law coefficient (HJ can be defined any number of ways, and so can be 

reported in various units. Here, we are assuming that H, = C, / C,, where C, is the concentration 

of the contaminant in air at equilibrium with Cw,the concentration of the contaminant in water. 

. 
Packed tower aerators 

In packed tower aerators (PTA). the contaminated water flows downward by gravity over a 

bed of packing material such as fixed plastic grids, loose plastic rings, or loose ceramic saddles, 

while air is blown upward through the column. The packing material breaks the surface area for 

contact between air and water thus promoting transfer of the contaminant into the gaseous phase. 

The removal efficiency of contaminants using PTAs depends upon the air to water ratio, 

contact time, available surface area, water loading rate, physical and chemical characteristics of 

the contaminant, and water and air temperature. 

The air flow requirements for a packed tower depend on the Henry’s Law coefficient for the 

particular compound to be removed from the water. In an ideal system, the greater the Henry’s 

Law coefficient for a compound, the less air is required to remove a contaminant from water. 

However, air to water ratios used to achieve a given removal efficiency are greater than the ideal 

system. 

The contact time is a function of the depth of the packing material. As the depth of packing 

materials increases, the contact time between the water and air increases, thereby causing high 

percent removals of the contaminant. 

The available surface area for mass transfer depends upon the packing material. Smaller 

packing materials provide greater available area for mass transfer per volume of material thus 

increasing the mass of contaminant removed. The pressure drop for the air passing through the 

column must be considered M hcn selecting packing materials. 

The water loading rate is the amount of water that passes through the tower and is largely a 

function of diameter of the touer. The water loading rate typically ranges from 25 to 30 gpdft’ 

(AWWA and ASCE 1998). 

PTAs are very efficient in removing several compounds from water. PTAs are considered 

Best Available Technologies (BAT) for several organic compounds. PTA can generally be used 

with systems of all sizes. A typical PTA consists of a packed column or tower, blower, pumping 

unit, and an effluent storage unit. Pretreatment may be necessary for removal of 

microorganisms. iron. Mn, and excessive particulate matter. PTAs are usually located outdoors, 

therefore piping may need to be protected in cold climates. 
Diffuser aerators 

Diffused aeration (DA) is the process of bubbling air into a water-filled contact chamber 

through a diffuser mechanism located at or near the bottom of the chamber. The chamber can 

either be a column or basin. The efficiency of diffused aeration for removing organics depends 

upon the diffuser type, air-to-water ratio, depth of the water in the contact chamber, detention 

time, and water temperature. Diffused aerators are generally used only to adapt existing plant 

equipment. 

Multi-stage bubble aerators (MSBA) are a form of commercially available package plant. 

These are a variation to the traditional diffused aerator. Typical commercial units consist of a 

high-density polyethylene vessel partitioned into multiple stages with an individual aerator for 

each stage. MSBAs are compact, with water depths typically less than 1.5 ft (compared to 

depths of 10 to 20 ft for typical aeration basins). If housing is required for the aeration unit, 

MSBA’s compactness can be very attractive. Other advantages of MSBA include removal 

efficiencies that are competitive with PTA. 

The advantages of a diffuser aeration system is that an existing basin or storage tank can 

be modified to be used as a diffuser aeration unit. Due to reduced pumping costs, no packing 

material costs, and potentially lower energy costs, marginal savings may be incurred. However, 

an increase in contact time and air-to-water ratios may be needed to achieve good removals 

because DA generally does not provide for convective movement of the water and thus does not 

allow as much contact between the air and water as other methods. 

Point-Of-Usepoint-Of-Entrv Aeration Technoloeies 

Point-of-use aeration technologies are not practical for volatile contaminants because 

routes of exposure can occur through inhalation, direct contact, and ingestion from a secondary 

faucet. Therefore, POU aeration technologies are not considered for compliance technology 

listing. 

Air stripping technologies such as PTA and diffused bubble aerators have been used in 

POE systems to remove VOCs from ground water (NRC 1997). Similar to other aeration 

technologies, these systems rely on mass transfer to remove VOCs from water. While POE 

aeration is technically feasible, it is not commonly used for public water systems and may not be 

as cost effective as other aeration systems. 

bd

34 

. 
-- 

MultiDle tray aerators 

Tray aerators (Cornwell 1990, AWWA-ASCE 1998) consist of a series of trays with 

slats, perforations, or wire mesh bottoms over which water flows and collects at the base of the 

unit. The thin film of water formed as the water flows over the media provides a large surface 

area for mass transfer of the contaminant from water to air. These aerators can be operated with 

a natural draft or with a forced draft using an air compressor. Using the natural draft reduces 

operating costs, but is less efficient than using a forced draft. 

Shallow tray aerators (STA) are another form of low-profile package plant. In STA, the 

contaminated water flows along the trays while air is blown through hundreds of holes in the 

bottom of the trays, creating a large mass-transfer surface area where contaminants are 

volatilized. These units are analogous to MSBA in terms of their advantages, including 

potentially high removal efficiencies and compactness. 

Multiple tray aerators can be used with systems of all sizes. These aerators are very 

efficient in removing co-occurring VOCs. However, higher air-to-water ratios may be required 

to ensure volatilization of the contaminants. One disadvantage is that slime and algae can grow 

on the trays, possibly necessitating the addition of copper sulfate or chlorine to control growth 

(NRC 1997). However, in shallow tray aerators, precipitation and biofilm development is 

minimal because of the vigorous bubbling action created by air flowing through the tiny holes 

(Lamarre 1993). 

Sprav Aerators 

Spray aerators produce small water droplets by spraying water through nozzles. The 

small droplets produced expose a large interfacial surface area through which contaminants can 

migrate from the liquid phase to the gaseous phase. Installations commonly consist of fixed 

nozzles on a pipe grid. 

The factors which affect the removal efficiency of spray aerators are size of the water 

droplets formed (area for mass transfer), height of spray (contact time), and temperature. The 

advantages of spray aerators include the capability of achieving efficient mass transfer due to the 

small water droplets created by the fixed nozzles and the lack of any packing costs. The 

disadvantages includes the need for large operational area. 
Mechanical aerators 

Mechanical aeration introduces air into the water by rapidly agitating the water surface 

with a mechanical mixer. The advantage to using mechanical aerators is that they are adaptable 

to existing basins, and are often installed as a system retrofit. However, these units are not as 

efficient as other aeration units. Because of the limited contacting system between air and water, 

large basins, long residence times, and high energy inputs may be needed to increase the 

efficiency of the aerator. These systems are applicable when low level contaminant removal is 

needed to reach the MCL. 

Gas-Dermeable membrane aeration 

Gas-permeable membrane aeration processes consist of a membrane module made up of 

highly porous, small diameter, hollow fiber membranes as a contacting device, providing an airwater contact area per equipment volume nearly an order of magnitude greater than packed tower 

air strippers (Semmens et al.; Zander et a]. 1989). Water flows through the interior of hollow 

membrane tubes constructed of a material that allows gases but not liquids to pass through. The 

large surface area for air-water contact allows for removal of semivolatile and volatile organic 

chemicals (NRC 1997). Gas-permeable membrane systems offer the highest removal 

efficiencies of all contacting devices. Membrane technology has to be considered emerging 

because long-term performance has not been evaluated. 

Air StriDpinc Suitabilitv for Small S\.stcms 

Overall an aeration system can generally be installed for a fairly low cost, and most 

aeration units are not complex. The treatment process is highly adaptable to small treatment 

plants. often involving a simple retrofir to misting treatment basins. Cost and treatment 

efficiency both increase with increasing system complexity. If contaminant concentrations are 

high and regulations require treatment of the air leaving the system, however, costs increase 

dramatically. The specific type of aerator depends only on the degree of contaminant reduction 

desired. Also. because mixtures of contaminants exist in contaminated water and even though 

the effectiveness of the process varies for each contaminant, aerating to remove one specific 

contaminant will also reduce concentrations of the others. 

Air StriDping Limitations 

The secondary effects of aeration ma!. be a problem. These include potential air quality 

problems created by exhaust gases from the aerator, and the potential for water quality 

deterioration from airborne particulates. oxidized inorganics, instability resulting in corrosion, 

and biological growth in the aeration device. Post-treatment disinfection may be needed after 

treatment with some of the aeration units. Depending on the water system's location, off-gas 

may have to be treated using a scrubber. thereby increasing the complexity and the cost of the 

aeration units. 
CoaPulation/ - Filtration

Coagulatiordfiltration (C/F) processes involve the addition of chemicals like iron salts, 

aluminum salts, or cationic polymers that coagulate and de-stabilize particles suspended in the 

influent, so that they may be ultimately removed via clarification and/or filtration. The C/F 

processes described in “Small System Compliance Technology List for the Surface Water 

Treatment Rule and Total Coliform Rule” (EPA 1998c) include “conventional filtration”, which 

includes a clarification step before filtration, and “direct filtration”, which does not. This 

discussion assumes that C/F processes would be added primarily to deal with microbial 

contaminants. As such, it is recommended that the compliance technology guidance for the 

SWTR (EPA 1998c) be consulted for details. 

Conventional Filtration 

Conventional filtration includes pre-treatment steps of chemical coagulation, rapid 

mixing, and flocculation, followed by floc removal via sedimentation or flotation. After 

clarification, the water is then filtered. Common filter media include sand, dual-media, and trimedia. Design criteria for specific sites are influenced by site-specific conditions and thus 

individual components of the treatment traih may vary in design criteria between systems. Most 

of the concerns regarding conventional filtration are specific to the Surface Water Treatment 

Rule (SWTR) and are discussed elsewhere (EPA 1998~).The main issue is that conventional 

filtration does not work properly if the coagulation chemistry is incorrect, so that operator skill is 

of paramount importance. since the operator must frequently monitor water quality and must 

know how to correct coagulant dosages in response to water quality changes (EPA 1990, NRC 

1997). 

Direct Filtration 

Direct filtration has several effective variations, but all include a pre-treatment of 

chemical coagulation followed by rapid mixing. The water is then filtered through dual- or 

mixed-media using pressure or gravity filtration units. Pressure units, which are used primarily 

by small systems, have the advantage of not requiring repumping for delivery of the filtrate to the 

point of use. Gravity units have the advantage of allowing easy visual inspection of the filter 

medium during and after backwash. Besides the mode of filtration, variations of direct filtration 

include filter media and mixing requirements. In-line filtration is the simplest form of direct 

filtration and consists of filters preceded by direct influent chemical feed and static mixing. In 

general. direct filtration usually requires low turbidity raw water and is attractive mainly because 

of its low cost relative to conventional treatment. Again, advanced operator skill and proper 

monitoring are required. 
Ion exchange 

Ion exchange (IX) involves the selective removal of charged inorganic species from water 

using an ion-specific resin (AWWA 1990, AWWA-ASCE 1998). The surface of the ion 

exchange resin contains charged functional groups that hold ionic species by electrostatic 

attraction. As water containing undesired ions passes through a column of resin beds, charged 

ions on the resin surface are exchanged for the undesired species in the water. The resin, when 

saturated with the undesired species, is regenerated with a solution of the exchangeable ion. A 

large variety of synthetic resins is available for specific applications. . 

Generally, resins can be categorized as anion exchange or cation exchange resins. Anion 

exchange resins selectively remove anionic species such as nitrate (NO?) and fluoride (F-). 

Anion exchange resins are often regenerated with sodium hydroxide or sodium chloride 

solutions, which replace the anions removed from the water with hydroxide (OH-)or chloride 

(C1-)ions, respectively. Cation exchange resins are used to removeundesired cations from water 

and exchange them for protons (H-).sodium ions (Na’) or potassium ions (K). 

Water to be treated by IX must be low in solids to avoid fouling the resin. In particular, 

reduced iron species in ground water may become oxidized when the water is exposed to oxygen 

in the atmosphere and form precipitates that can damage the resin. 

A resin may preferentially remove certain ions from solution. In general, it will remove 

highly charged ions more easil) than it will remove monovalent ions. Calcium, magnesium, and 

reduced iron ions will be removed preferentially to other cations. The presence of such species 

may reduce removal efficiencics (NRC 1997). 

An operator must monitor the s!’stem to determine the extent of resin saturation or the 

breakthrough of the ion to hc rcrnotvd. On ion breakthrough, the resin must be removed from 

service and regenerated. IX unit3 can be controlled automatically, freeing the operator to make 

daily visits (rather than attending to the systems full-time) td assure proper operation. 

In either the cation or anion exchange process, the regeneration solution, which contains 

high concentrations of the undesired ions, must be carefully disposed of. Disposal can be quite 

costly, especially in the case of concentrated radionuclides (NRC, 1997). 

Stakeholders requested that EPA state that IX can be operated in a “merry-go-round” 

configuration to achieve low levels of contaminants in the effluent and to minimize regeneration 

frequency. An example would be the use of three beds in series: two in production and one in 

regeneration mode at any given time. When exchange capacity of the first bed in series is 

exhausted, the first bed is removed from service to be regenerated. The second bed in series then 

becomes the first and a fresh regenerated bed is brought on-line to become the second. This 

maximizes the exchange capacity of the beds and prevents leakage since a fresh bed is always 

last in line (EPA 1994). In addition to the “merry-go-round” approach, single, deep bed, 

Pf. 

38 
. 

counter-current flow processes can also increase the usable capacity of the IX bed and reduce 

leakage (EPA 1995). 

IX is a common water treatment technology for small systems. IX is available in the 

form of point-of-use (POU) and point-of-entry (POE) devices as well as in the form of full-scale 

treatment. An advantage to IX is that it can be used under fluctuating flow rates (NRC 1997). 

The technology does produce highly concentrated waste by-product streams that may be an 

issue; brine recycling might reduce this impact somewhat. With IX, the primary factor in 

calculating costs is the regeneration frequency, and competition with other ions will affect the 

run length. For example, anion exchange would be recommended primarily for small ground 

water systems with low sulfate and TDS. 

Lime softenin? 

In the lime-softening (LS) process, the pH of the water being treated is raised sufficiently 

to precipitate calcium carbonate and, if necessary, magnesium hydroxide. Calcium and 

magnesium ions in water cause hardness; hard water can cause scaling problems in water heaters, 

and soap ‘lathers poorly in hard water. In small systems, LS would typically be practiced by 

adding hydrated lime to raw water to raise the pH to approximately 10. This removes calcium 

carbonate. If magnesium removal is also required, the pH during softening would need to be 

closer to 1 1. In some waters, addition of soda ash is needed for effective hardness removal. 

After mixing, flocculation, sedimentation. and pH readjustment, the softened water is filtered 

(NRC 1997). In addition to removing calcium and magnesium, LS also removes radium and 

several inorganics (including arsenic). 

Many large water systems use LS to treat surface waters. However, the combination of 

variable source water quality and the complexity of the chemistry of LS may make it too 

complex for small systems that use surface water sources. LS may be more appropriate for small 

systems that use ground water because of the relative uniform quality of ground water. Once the 

softening chemistry for a ground water is determined, it should not change much. In comparison, 

chemical additions to surface waters need to be modified frequently in response to water quality 

changes (NRC 1997). 

One of the difficult aspects of LS is the operation and maintenance of lime feeders and 

lines carrying lime slurry to the point of application. In addition, plant operators must 

understand lime softening chemistry. Measurement of pH must be accurate, and the operator 

must know that the pH meter is properly calibrated. Failure to maintain the proper pH in 

softened water prior to filtration at a lime softening plant could result in precipitation of excess 

lime in the filter beds and formation of calcium carbonate deposits within the filters. 

LS is similar to coagulatiodfiltration in that pre-fabricated equipment is available. LS 

may be a feasible technology in the larger small ground water systems. For the smaller 

categories, LS may be feasible by using some form of contract or satellite operation that would 
enable a trained operator to monitor the process periodically. 

Membrane Processes 

Four membrane processes are discussed in this document: reverse osmosis (RO), 

ultrafiltration (UF), nanofiltration (NF), and electrodialysis/electrodialysisreversal (EDEDR). 

All of these processes share certain characteristics, since they all involve membranes, but RO is 

distinct in that it involves a non-porous membrane and ED/EDR in that it involves a ion selective 

membrane. Membranes are manufactured in a v,arietyof configurations, materials and pore size 

distributions. The selection of membrane treatment for a particular drinking water application is 

determined by a number of factors, including: targeted material(s) to be removed, source water 

quality characteristics, treated water quality requirements, membrane pore size, molecular weight 

cutoffj (MWCO), membrane composition, and systedtreatment configuration (Jacangelo 1991). 

In general, membrance processes show little economy of sde, since capital costs per 

volume of water treated do not increase dramatically as design flows decrease. For this reason, 

and others discussed below, membrane technologies can be a good choice for addressing many 

small systems water quality problems. For ground water systems not requiring pre-treatment, 

membrane technology addition requires little more than a feed pump, a cleaning pump, the 

membrane modules, and holding tanks (NRC 1997). Membrane technologies can be more costeffective than more conventional treatments for controlling a host of water quality problems 

(Wiesner et ai. 1994, Bergman 1996). 

Ultrafiltration and Nanofiltration 

Ultrafiltration and nanofiltration are “membrane filtration” processes, in that they work 

by excluding contaminants due to pore size constraints (Adham et al. 1996, Agbekodo et al. 

1996). The water is forced by pressure from the source water side (concentrate) through the 

pores of a semi-pemeable membrane to the produced water side (permeate). Impurities are 

prevented from passing through the membrane by size exclusion, ana so are retained in the 

concentrate. The permeate is generally of a very high quality (NRC 1997). 

Membrane classification standards vary between manufacturers. For example, one 

supplier may classify a membrane as nanofiltration, while another supplier may classify a similar 

membrane as ultrafiltration. Also, some manufacturers refer to average pore size and some to 

maximum pore size. For these reasons, water systems should make sure that the reported pore 

size is adequate for the required purposes by looking directly at pore size, MWCO, and the 

required applied pressure. 

MWCO is defined as an estimate of the molecular weight of the smallest molecule that 

will be retained by the membrane. 

* 
The operation of ultrafiltration and nanofiltration processes are substantially less 

complicated than the operation of the treatment trains needed to achieve similar removals via 

conventional technologies. In particular, membrane processes may be very appropriate for small 

systems attempting to remove multiple contaminants. If pre-treatment is required, the 

complexity of the required operations can of course increase appreciably. In addition, specific 

site testing to analyze the potential for organic fouling may be required. However, there are few 

limitations to the types of raw water that can be handled by membrane processes and, if needed, 

pre-treatment (NRC 1997, AWWA - ASCE 1998). 

Reverse Osmosis 

Reverse osmosis (RO) is a highly efficient removal process for inorganic ions, some 

organic contaminants, and, in some cases, microbiological contaminants (EPA 1990, Logsdon et 

al. 1990, NRC 1997, AWWA-ASCE 1998). RO resembles membrane filtration processes since 

they all involve passing water through a semi-permeable membrane- However, in the case of 

RO, the principle involved is not filtration. Instead, it involves the use of applied hydraulic 

pressure to oppose the osmotic pressure4across a non-porous membrane, forcing the water from 

the concentrated solution side to the dilute solution side. Since the membrane is non-porous, the 

water does not travel through pores, but rather dissolves into the membrane, diffuses across, then 

dissolves out into the permeate. Any contaminant that can likewise dissolve into the membrane 

and pass into the permeate will not be rejected by the RO membrane. However, most inorganic 

contaminants of interest and many organic contaminants are rejected by the membrane and will 

be retained in the concentrate. RO produces a larger volume of concentrate (reject) solution than 

membrane filtration processes. The concentrate volume can be as much as 25 to 50 percent of 

the raw water volume. Drinking water treatment can be accomplished with lower pressure 

versions of RO (125 to 300 psi), with feasible recoveries of 70 to 85% (AWWA - ASCE 1998). 

Removal efficiencies for inorganic contaminants range from 85 to > 99%. Removal for 

organic contaminants are highly variable depending upon the contaminant and the water quality. 

Lower molecular weight organic molecules and organic molecules that have an affinity for the 

membrane may diffuse through the membrane. The degree to which the contaminant passes 

depends on the contaminant-s molecular weight and its chemical nature. Removal efficiencies 

for organic compounds range from greater than 99% to no removal at all. 

An RO membrane can foul if the influent is not pre-treated, depending upon the quality of 

the raw water (AWWA-ASCE 1998). Influent total organic carbon (TOC) levels can be as high 

as 20 mg/L without requiring pre-treatment (NRC 1997), but the influent have low turbidity, 

iron, manganese, and chlorine or pre-treatment is required. Groundwater waters may have low 

Osmotic pressure is defined as the pressure that arises from the natural tendency of a 

solvent like water to pass from the dilute solution on one side of a semi-permeable non-porous 

membrane to the concentrated solution on the other side. 
enough TOC levels and turbidity, but may require removal of iron and manganese. Applying 

disinfection after the membrane process can obviate the need to remove chlorine beforehand. 

Since the permeate has very low mineral content and alkalinity, it can be quite corrosive. 

The usual practice to reduce corrosivity is to blend, i.e., bypass a pre-determined percentage of 

the raw water to the permeate. Other possible measures include de-gasification of carbon dioxide 

and/or hydrogen sulfide (both are acids in water) or pH adjustment through the addition of a 

chemical base, like sodium hydroxide. Post-treatment disinfection is also a common practice. 

Usually, RO systems have automatic backwash features, reducing labor requirements. 

The skill requirements for the daily operation of common pre-treatment processes are often 

greater than the membrane process itself. However, periodic cleaning of the membrane surface is 

required. Care must be taken to avoid contamination of the raw or finished water with the acidic 

post-wash solution. Also, the membrane should be flushed with permeate to prevent later 

scaling. If the plant is taken out of operation for days at a time, themembranes should be filled 

with a disinfection solution to prevent biological growth, which can damage the membrane 

(NRC 1997). 

Electrodialvsis (ED) and electrodialvsis reversal (EDR) 

Electrodialysis (ED) and electrodialysis reversal (EDR) are usually used for demineralizing water from brackish water sources. They involve electrochemical separation 

processes to concentrate salts from the feed water into smaller-volume, higher-concentration 

solutions within collection channels. ED and EDR systems consist of stacks of alternating 

anionic and cationic selective membranes. The ionic constituents pass through the membranes in 

response to an electric current applied perpendicularly to the membrane surfaces. This results in 

an alternating sequence of de-mineralized water streams and concentrate streams (NRC 1997. 

AWWA - ASCE 1998). The principal difference between ED and EDR is that EDR involves the 

additional step of a change in electrode polarity every 15 to 20 minutes, causing a reversal in ion 

movement. This step minimizes scale buildup on the membranes and thus EDR can operate for 

longer time periods between cleanings. The majority of plants using ED technology in the 

United States use EDR (NRC 1997). 

ED/R systems require feed water pre-treatment. Cartridge filtration is often the minimum 

requirement. Turbidity should be less than 2 NTU, free chlorine levels less than 0.5 mg/L, 

manganese less than 0.3 mg/L, and hydrogen sulfide less than 0.3 mg/L (Conlon 1990). Total 

dissolved solids up to 4,000 mg/L have been successhlly handled by EDR plants (NRC 1997). 

Unlike membrane filtration and RO, the product water does not pass through the ED/R 

membranes, so the potential for organic fouling is reduced. Unfortunately, another consequence 

is that microbiological, most organic, and colloidal/particulate contaminants are not removed 

from the product water. Standards for these contaminants must be met through pre-treatment or 

other means, if necessary. And like other membrane processes, some bypassed water (or other 

-
measures) may be required to reduce the corrosivity of the product water. ED/R systems usually 

operate at 70% recovery (NRC 1997). 

A principal disadvantage of EDR is the high energy consumption. Pumping costs are 

similar to costs for ultrafiltration, but process power costs roughly equal pumping costs for 

ED/R. 

More than half of the EDR systems in operation in North America serve fewer than 

3,500 persons, with some serving fewer than 200, Since ED/R plants are amenable to automatic 

operation, part-time operators may be sufficient, depending upon pre- and post-treatment 

requirements. 

Membrane Process Waste Disposal Considerations 

Waste stream disposal is often the most important consideration (NRC 1997). Waste 

stream disposal can pose a significant problem in some areas, since waste volumes are larger 

than for conventional treatment . Because membrane filtration processes require little or no 

chemical addition, the concentrate usually contains only the contaminants found in the source 

water, and so disposal of the concentrate into the source water may be feasible. Other 

alternatives include sanitary sewer discharge, deep well injection, dilution, and spray irrigation 

(Pontius et al. 1996, USEPA 1996). Careful planning may be required to legally and safely 

dispose of membrane concentrate wastes. A potentially time consuming part of the process 

involves obtaining regulatory permits. In the vast majority of cases, an acceptable waste disposal 

method can be successfully implemented and permitted (Pontius et al. 1996). 

Disposal of RO and EDR reject water poses a potentially more serious problem than the 

membrane filtration processes, because of the large concentrate volumes. Municipal sewer 

disposal and deep well injection are conventional waste handling strategies. The use of 

evaporation ponds is another possibility, but is normally used only when conventional means are 

not possible, because of the high associated costs and land requirements. For areas with very low 

land costs. this may be a feasible alternative for small systems (EPA 1997a). 

References 

Adham. S.S., Jacangelo. J.G., and Laine, J-M. “Characteristics and Costs of MF and UF Plants”. 

JAWWA 88(5). p. 22. May 1996. 

Agbekodo, K.M., Legube, B., and Cote, P. “Nanofiltration Yields High-Quality Drinking Water 

in a Paris Suburb”. JAWWA 88(5). p. 67. May 1996. 

American Water Works Association. Water Oualitv and Treatment: A Handbook of Communitv 

Water Supplies. 4‘hed.. Pontius, F., ed. McGraw-Hill. New York. 1990. 
American Water Works Association and American Society of Civil Engineers (AWWA and 

ASCE). Water Treatment Plant Design. Third Edition. McGraw-Hill. New York. 1998. 

Bergman, R.A. “Cost of Membrane Softening in Florida”. JAWWA 88(5). p. 32. May 1996. 

Cornwell, D.A. “Air Stripping and Aeration”. AWWA, Water Oualitv and Treatment: A 

Handbook of Communitv Water Supplies. 4’hed.. Pontius, F., ed. McGraw-Hill, Inc. New 

York. 1990. 

Goodrich, J.A., Adams, J.Q., Lykins, B.W., Jr., and Clark, R.M. “Safe Drinking Water from 

Small Systems: Treatment Options”. JAWWA. 84(4). p. 49. May 1992. 

Jacangelo, J.G. “The Development of Membrane Technology”. International Report (IR 3) 

Water Supdy: Review Journal of the International Water SupDlv Association. Vol. .9, Numbers 

3/4. 1991. % 

Lamarre. B. Selecting an Air Strimer-What to Consider. The National Environmental Journal, 

July/August. 1993. 

Logsdon. G.S., Sorg, T.J., and Clark, B.M. “Capability and Cost of Treatment Technologies for 

Small Systems”. JAWWA. 82(6). p. 60. June 1990. 

Lykins, B.W., Jr.. Clark, R.M., and Goodrich, J.A. Point-of-Use / Point-of-Entrv for Drinking, 

Water Treatment. Lewis Publishers. Ann Arbor, MI. 1992. 

National Research Council (NRC). (1997). Safe Water From Everv TaD: Improving Water 

Service to Small Communities. Committee on Small Water Supply Systems. Water Science and 

Technology Board. Commission on Geosciences, Environment, and Resources. National 

Academy Press, Washington, DC. 1997. 

Pontius, F.W.. Kawczynski, E., and Koorse. S.J. “Regulations Governing Membrane 

Concentrate Disposal”. JAWWA 88(5). p. 44. May 1996. 

Semmens. M.J.. R. Qin, and A.K. Zander. “Using Microporous Hollow-Fiber Membranes to 

Separate VOCs from Water”. Journal of the American Water Works Association 8 l(4): 162-167. 

1989. 

Snoeyink, V. L. “Adsorption of Organic Compounds”. AWWA, Water Quality and Treatment: 

A Handbook of Community Water Supplies. 4‘hed.. Pontius, F., ed. McGraw-Hill, Inc. New 

York. 1990. 

USEPA. “Technologies for Upgrading Existing or Designing New Drinking Water Treatment 

Facilities”. Office of Drinking Water. EPA/625/4-89/023. March 1990. 

I 
. 

USEPA. “Technical and Economic Capacity of States and Public Water Systems to Implement 

Drinking Water Regulations: Report to Congress”. Office of Water. EPA 8 10-R-93-00 1. 

September 1993. 

USEPA “Summary of Arsenic Treatment Workshop”, January 18, 1994. 

USEPA. “An SAB Report: Review of Issues Related to the Regulation of Arsenic in Drinking 

Water”, EPA-SAB-DWC-95-015, July 1995. 

USEPA. “Technology Transfer Handbook: Management of Water Treatment Plant Residuals”. 

Office of Research and Development. EPA/625/R-95/008. April 1996. 

USEPA. “Announcement of Small Systems Compliance Technology Lists for Existing National 

Primary Drinking Water Regulations and Findings Concerning Variance Technologies”. Federal 

Register. Vol. 63, No. 151. p. 42032. August 6, 1998. (EPA 19984. 

USEPA. “Draft Technologies and Costs for the Removal of Arsenic from Potable Water 

Supplies”. July 1998. (EPA 1998b). 

USEPA. ”Small System Complisncc Technology List for the Surface Water Treatment Rule and 

Total Coliform Rule”. EPA 8 1 5-K-98-00 1. Office of Water. September 1998. (EPA, 1998c)

Wiesner, M. R.. Hackney. J.. Scthi. S.. Jacaneglo, G., and Laine, J. M. “Cost Estimates for 

Membrane Filtration and C‘on\cnlionsl Treatment”. JAWWA. 86( 12). pp. 33 - 41. 1994. 

I 
4. AFFORDABLE TECHNOLOGY DETERMINATIONS 

Section 4.1: National-Level Affordability Criteria 

As discussed in Section 1.3, EPA did evaluate technologies for each small size category 

against an affordable technology criterion for those regulations where a small system variance 

could be granted. The size category-dependent affordable technology criteria are collectively 

referred to as “national-level affordability criteria.” This nomenclature has been used to 

distinguish the national-level affordability criteria from the affordability criteria that States will 

use for determinations affecting individual systems. EPA published information regarding these 

“system-level affordability criteria” in February, 1998 (EPA 1998a). This information was 

required by Section 1415(e)(7)(B) of the SDWA. There are three provisions of the SDWA that 

refer to these “system-level affordability criteria.” Section 1415(e) provides for affordabilitybased variances, under certain circumstances, for small drinking water systems. Section 1416 

allows for exemptions that provide systems facing compelling economic factors additional time 

to comply with SDWA requirements. Small systems could receive as long as nine additional 

years to comply. Finally, Section 1452(b) provides that affordability on a per household basis 

shall be one of the three factors used to prioritize systems for assistance from the new Drinking 

Water State Revolving Fund (DWSRF). The system-level affordability criteria can be different 

for different purposes. For example, States can use different affordability criteria to make 

decisions about whether a system should receive a small system variance and when a system 

should receive additional subsidization from the DWSRF. In fact, the threshold used for 

additional assistance for systems meeting a NPDWR would likely be lower than the threshold 

used to determine when a system would operate at a level that does not provide an equivalent 

level of protection as meeting the MCL. 

The national-level affordability criteria used to determine if there is an affordable 

variance technology will also be different from the system-level criteria used by the State to 

determine if a system should receive a small system variance. Technologies determined to be 

“unaffordable” under the national-level affordability criteria may still be affordable for a specific 

system within the size category, in which case the system may install that technology if it so 

chooses. Conversely. if a financially disadvantaged small water system out of compliance with a 

NPDWR cannot afford any of the compliance technologies that are determined to be ‘.aff&dable” 

under the nation-level affordability criteria, one option for that system would be to apply to the 

State for an exemption. This process is available for regulations promulgated after 1996. Such a 

system cannot apply for a new exemption for the regulations issued prior to 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 has run out. That means 

that a small system can have no more than 9 years after the Section 1412 compliance date to 

meet the applicable MCLhreatment technique even if the exemption was issued prior to the 1996 

SDWA Amendments. 

To determine if there are any affordable compliance technologies for a given NPDWR, 
the national-level affordability criteria are compared against the cost estimates for the applicable 

treatment technologies. To make this comparison, there must be a consistent unit of measure for 

both parameters. The selected approach was to measure user burden as the increase to annual 

household water bills that would result from installation of treatment. ' For community water 

systems, the household was selected as the most sensitive user for cost increases (EPA 1998b). 

Non-community water systems (NC WSs) were also evaluated by comparing their vulnerability 

to cost increases with households in community water systems. The conclusion, based on this 

comparison, was that the categories of NCWS were either not vulnerable to SDWA-related 

treatment cost increases or were less vulnerable to SDWA-related treatment cost increases than a 

typical household (EPA 1998c). 

A summary of the methodology used to determine the national-level affordability criteria 

is described below. The household is the focus of the national-level affordability analysis. 

Treatment technology costs are presumed affordable to the typical household if they can be 

shown to be within a range (defined as a range of percentages of median household income) that 

appears reasonable when compared to other household expenditures. This approach is based on 

the assumption that affordability to the median household served by the CWS can serve as an 

adequate proxy for the affordability of technologies to the system itself. EPA has chosen to 

express the water system financial and operational characteristics using their median values, 

which is a measure of their respective central tendencies. EPA believes that the 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. 

After selecting the impacts on households as the measure for comparing national-level 

affordability and treatment costs. a consistent set of units was needed to make the comparison. 

The treatment cost models produce rate increases measured in dolladthousand gallons ($/kgal). 

Annual household water consumption is needed to convert the treatment technology costs into 

the increase in annual household water bills. The water consumption estimates were multiplied 

by 1.15 to account for lost water due to leaks. Since the water lost to leaks is unbilled, the water 

bills for the actual water used needed to be adjusted to cover this lost water by increasing the 

household consumption. Multiplying the rate increase by the adjusted annual household 

consumption yields the increase to annual household water bills ($/household/year increase). 

The national-level affordability criteria have two major components: current annual water 

bills (baseline) and the affordability threshold. The current annual household water bills were 

subtracted from the affordability threshold to determine the maximum increase that can be 

imposed by treatment and still be considered affordable. This difference was compared with the 

converted treatment costs to make the affordable technology determinations. This difference is 

called the available expenditure margin. 

The baseline costs include existing water quality, water production, and water distribution 

costs. Water production costs include labor and energy for pump operation to supply water to 

customers. Water distribution costs include costs of infrastructure repair (mains and service 

47 
lines) and administrative costs (customer billing and meter checking). The existing water quality 

costs include both treatment and monitoring. The data utilized to determine the baseline were 

collected in 1995, so treatment costs for many of the regulated contaminants may already be 

accounted for in the baseline. 

The affordability threshold was determined by comparing the cost of public water supply 

for households with other household expenditures and risk-averting behavior. National 

expenditure estimates were derived to illustrate the current allocation of household income across 

a range of general household expenditures. This consumer expenditure data provided a basis for 

determining the affordability threshold by comparing baseline household water costs to median 

household income (MHI) to determine the financial impact of increased water costs on 

households. 

There are three parameters needed for each size category to perform the affordable 

technology analysis. These parameters are: annual household consumption, current annual water 

bills, and median household income (MHI). The annual household water consumption and the 

current annual water bills were derived directly from data in the 1995 Community Water System 

Survey (EPA 1997a, EPA 1997b). The MHI data were derived by linking the CWSS data with 

data in the 1990 Census using zip codes. 

The national-level affordability criteria are based on an affordability threshold of 2.5% of 

the MHI for each size category (EPA 1998d). For each size category, median values have been 

used for annual household water consumption, baseline annual water bills, and median household 

income. The baseline water bills ranged from 0.65% to 0.69% MHI in the three size categories. 

Thus. the available expenditure margin were approximately 1.8% MHI for each size category. 

Table 4-1 summarizes the national-level affordability criteria and shows the maximum increase 

that could occur using these criteria. The numbers in this table are slightly different from the 

numbers in the Federal Register notice (EPA 1998e). There were some minor changes in the 

baseline values for current water bills and median household income (EPA 1998d). Most 

systems would not be expected to actually experience cost increases of this magnitude if a 

compliance technology was installed. Many compliance technologies impose substantially lower 

household costs. For example. the screening process examined several technologies that 

imposed less than $300/household per year increases in all three size categories. Appendix F of 

the “National-Level Affordability Criteria Under the 1996 Amendments to the Safe Drinking 

Water Act” report lists mitigating measures that could reduce the impact on households. In 

addition. the national-level affordability criteria do not consider the impact of financial assistance 

from State Revolving Fund loans or other sources. This financial assistance could also reduce 

the impact on households in those systems that qualify for financial assistance. For more detail 

on the national-level affordability criteria, see the “Variance Technology Findings for 

Contaminants Regulated Before 1996”(EPA 1998d) and the National-Level Affordability 

Criteria Under the 1996 Amendments to the Safe Drinking Water Act” (EPA 1998b) documents. 

-
1 
Section 4.2: Affordable Technology Analysis using National-Level Affordability Criteria 

Compliance technologies were evaluated against the national-level affordability criteria 

for those existing regulations where small system variances or variance technologies are not 

prohibited by the SDWA. When affordable compliance technologies are identified for these 

contaminants, technologies that can achieve compliance, but did not meet the.affordability 

criterion will also be identified. 

In general, technology cost estimates to treat all of the water were compared against the 

available expenditure margin for each size category (see Table 4-1). Technology cost estimates 

were derived for both central treatment options and centrally-managed Point-of-Use and Pointof-Entry device options. The procedures followed for this analysis are described in detail in 

Chapter 4 of the background document entitled “Variance Technology Findings for 

Contaminants Regulated Prior to 1996” (EPA 1998d). Based on this analysis, an affordable 

compliance technology was found for each of the five contaminants for all system sizes and 

expected source water qualities. For most of the system size/source water quality combinations, 

there are multiple affordable technologies. 

The national-level affordability criteria only played a role in removing some of the 

Options in the smallest sizc catcpries. The technologies that did not meet the affordability 

criteria in the smallest sizc catcgnp arc also identified as “other compliance technologies.” 

Since the technology costs ncrc brtscd on treatment of all of the water for this analysis, systems 

requiring lower removals ma) hittut the ”other compliance technologies” would pass the 

national-level affordabilit! criteria 11‘3 lower removal efficiency is required. A portion of the 

influent water could be trcrt~ccfand blcndcd with an untreated portion and the system could still 

meet the MCL. Under this qymuih. both the capital and operating and maintenance costs for 

the process would be reducccf 5) \tcni\ rind States should consider the “other compliance 

technologies” under thosc ciriuni~tmic~. 
-- 

References 

USEPA. “Community Water System Survey Volume 1 : Overview”. EPA 815-R-97-001a. 

Office of Water. January 1997. (EPA 1997a). 

USEPA. ‘‘Community Water System Survey Volume 11: Detailed Survey Result Tables and 

Methodology Report”. EPA 8 15-R-97-001b. Office of Water. January 1997. (EPA 1997b). 

USEPA. “Information for States on Developing.Affordabi1ityCriteria for Drinking Water” 

EPA-8 16-R-98-002. Office of Water. February, 1998. (EPA 1998a). 

USEPA. “National-Level Affordability Criteria Under the 1996 Amendments to the Safe 

Drinking Water Act”. Prepared by International Consultants, Inc., Hagler Bailly Services, Inc. 

and Janice A. Beecher. Ph.D. for the EPA. August 1998. (EPA 1998b). 

USEPA. ‘‘An Assessment of the \’ulnerability of Non-Community Water Systems to SDWA 

Cost Increases”. Prepared b!, Science Applications International Corporation for the EPA. July 

1998. (EPA 1998~). 

USEPA. “Variance Technolop Findings for Contaminants Regulated before 1996”. EPA 8 15-

R-98-003. Office of b’atcr. Scptcmhcr 1998. (EPA 1998d). 

USEPA. ”Announcement of‘SnulI S) stems Compliance Technology Lists for Existing National 

Primary Drinking Warer Kcgul;ltion\ and Findings Concerning Variance Technologies”. 

Federal Register. 63( 15 I 420;2 .August 6, 1998. (EPA 1998e). 
5. SMALL SYSTEMS COMPLIANCE TECHNOLOGIES FOR INORGANIC 

CONTAMINANTS, INCLUDING CORROSION BY-PRODUCTS 

Section 5.1: BackPround 

Seventeen inorganics are regulated. The interim MCL for arsenic was issued in 1975. A 

proposal for a new regulation for arsenic is expected by January 2000, and a final rule is 

expected by January 200 1. The final rule for fluoride was promulgated in April 1986. The final 

rule for the Phase I1 inorganics (asbestos, cadmium, chromium, mercury, nitrate, nitrite and 

selenium) was promulgated in January 1991. The lead and copper rule was promulgated in June 

1991. The final rule for Phase IIb (barium) was promulgated in July 1991. The final rule for the 

Phase V inorganics (antimony, beryllium, cyanide and thallium) was promulgated in July 1992. 

Issues with compliance technologies for inorganics treatment are discussed in Section 

5.2.2. A general description of these technologies can be found in Chapter 3. Corrosion control 

technologies are relevant for inhibiting lead and copper dissolution in the distribution system. In 

addition, corrosion control reduces release of other inorganics such as asbestos and cadmium. 

The corrosion control technologies are described in Section 5.2.1. Section 5.3 lists the 

compliance technologies for small systems and Section 5.4 describes emerging technologies. 

A short description of some of the key inorganics are given below: 

Lead and Copper: 

In June 1991, EPA promulgated a NPDWR for lead and copper consisting of a treatment 

technique requirement that includes corrosion control treatment, source water treatment, lead 

service line replacement and public education. Lead occurs in drinking water from two sources: 

(1) Lead in raw water supplies and (2) corrosion of plumbing materials in the water distribution 

system (corrosion by-products). Most lead contamination is from corrosion by-products. The 

primary source of copper in drinking water is corrosion of copper pipes, which are widely used 

throughout the United States for interior plumbing of residences and other buildings. In some 

cases, copper is a component of additives to drinking water used by systems to control the 

growth of algae (EPA 1991a). 

Asbestos: 

Asbestos fibers are relatively large particles. Asbestos fibers are generally of two types: 

chrysotile and amphibole. Chrysotile fibers are more common in water supplies and are usually 

less than 5 microns in length and approximately 0.1 microns in width. Amphiboles are on the 

order of 0.4 to 1.7 microns in length and 0.1 to 0.4 microns in width (Logsdon 1979, Kirmeyer 

1979a, Kirmeyer 1979b, Black & Veatch 1975). Because of the large size of the particles, the 

potential for using inexpensive membrane technologies exists. However, further research is 

required. 
Antimonj.: 

Antimony is found in over 100 mineral species; however, it does not occur in abundance. 

Metallic antimony is blueish white in color, with a metallic luster, and is extremely brittle, with a 

flaky, crystalline texture. Antimony has valence states in the -3, 0, +3, and +5 forms; antimony 

does not seem to occur in drinking water in the +3 and +5 states. Though ion exchange (IX) is 

an affordable, effective treatment technology for most inorganics, IX does not appear to be 

effective in removing antimony (EPA 1990). 

Fluoride: 

Fluoride commonly occurs in the earth's crust as fluorspar (CaF?), cryolite (Na,AIF,) and 

fluorapatite (Ca,,F,(PO,),) and ranks thirteenth among the elements in order of abundance. 

Concentrations as high as 9 to10 mg/l are not uncommon in some ground waters (Benefield 

1982). Fluoride has beneficial and detrimental effects. It can help prevent dental cavities when 

an optimum amount is present in drinking water. However, long-term consumption of water 

containing excessive amounts of fluoride can lead to fluorosis of the teeth and bones. The MCL 

for fluoride is 4.0 mg/l, and the secondary maximum contaminant level (SMCL) is 2.0 mg/l. The 

SMCL was set at 2 mg/l because that le\.rl Lvould prevent the majority of cases of water-related 

cosmetically objectionable dental fluorosis while still allowing for the beneficial effects of 

fluoride (EPA 1986a). 

Nitrate: 

Nitrate is a common ion found in most natural waters. It is the end product of the 

oxidation of ammonia. Because it is an algal nutrient it can promote algal blooms (Benefield 

1982). Nitrate is also a potential hazard to intants. Serious and occasionally fatal poisonings in 

infants have occurred following ingestion of \sell waters shown to contain nitrate at 

concentrations greater than 10 mg 'I of nitrate (asNitrogen). Well water. particularly shallow 

well waters. tend to have higher concentrations of nitrates than surface waters. The major 

sources of nitrate contamination has been from septic tank discharges, fertilizer in agricultural 

drainage, animal feedlots. domestic and municipal sewage, and industrial wastes (EPA 1984a). 

Arsenic: 

Arsenic occurs in two primary l'orms: organic and inorganic. Inorganic arsenic occurs in 

two valence states. arsenite (As Ill ) and arsenate (As V). Most natural waters contain the 

inorganic forms of arsenic. Groundkvaters generally contain As (111) and surface waters generally 

contain As (V). Arsenate is removed more efficiently that arsenite by the treatment technologies 

listed here. Therefore, if arsenite is the predominant species present, oxidation to arsenate may 

be required to achieve the desired removal. 

53 
Section 5.2 Evaluation of Technolopies 

Corrosion Control Technologies 

There are primarily three different approaches to control for corrosion in the distribution 

system. One approach is to cause a calcium carbonate precipitate to form inside the distribution 

system to protect the inside of the pipes. Another approach, referred to as passivation, is to 

change the water to be less corrosive without causing a precipitate to form. There are two 

methods of passivation. The first is to change the alkalinity and pH of the water. The second is 

to add an inhibitor (EPA 1992). The third approach to control for corrosion is to use aeration. 

Calcium carbonate precipitation 

The principle behind calcium carbonate precipitation is to maintain the concentration of 

calcium and carbonate high enough in the product water so that cakium carbonate precipitates 

out in the distribution system. The solids form a protective coating. This approach is only 

practical if the concentration of the calcium and carbonate are high enough in the influent water. 

If necessary, calcium can be added in the form of hydrated or quick lime. The carbonate can be 

adjusted by adding soda ash, sodium bicarbonate or carbon dioxide. The pH can be adjusted, if 

necessary, by adding these aforementioned chemicals and/or caustic soda, hydrochloric acid or 

sulfuric acid. Small system; should be aware of the complexities inherent in using lime and soda 

ash systems. These methods require a high degree of operator attention because the calcium 

carbonate plugs bins. tanks, pumps and piping. To keep downtime to a minimum the bins have 

to be kept dry. In addition, the feed systems must be acid cleaned. Small systems should also be 

aware of complexities in operating a sodium hydroxide system. In addition to avoiding calcium 

carbonate plugging of the sodium hydroxide feed system, small systems should also be aware 

that employees may have to handle a strong base; sodium hydroxide is usually delivered as a 50 

percent solution (EPA 1992). Stakeholders expressed a concern that this approach may also 

cause a build-up of precipitate in consumers’ hot water heaters. 

This control strategy is only appropriate for lead. It is not an effective strategy for copper 

for several reasons. First, a much larger surface area would need to be coated. Second, a 

calcium carbonate film may not establish on copper piping. Third, adjusting alkalinity for 

precipitation may produce a high alkalinity finished water which can be corrosive to copper. 
-- 

Passivation 

The other approach to corrosion control is passivation. In this case, the goal is to produce 

less corrosive water. A precipitate need not be created. 

Alkalinity and DH 

One method of passivation is to alter the alkalinity and the pH. This is appropriate when 

the water is not very hard and low in alkalinity. I This essentially involves use of the same 

chemicals (lime. soda ash. etc.) and feed systems as in calcium carbonate precipitation. An 

advantage of this approach is that small systems do not have to attempt the difficult task of 

forming a precipitate throughout the distribution system. Small systems should, however, be 

aware that employees might have to handle chemicals such as strong bases (EPA 1992). 

Limestone contactors 

A method of altering the alkalinity and pH that might be particularly applicable to the 

smaller systems is the use of limestone contactors (EPA 1987). This method would be 

applicable if the raw water was soft and slightly acidic. With this technology, the water flows 

through and dissolves a packed bed of crushed limestones. Because the raw water is slightly soft 

and slightly acidic, the calcium carbonate dissolves. Consequently, the pH. calcium and 

alkalinity increases. Limestone contactors have low capital and operation and maintenance costs. 

This technology is primarily recommended for the smallest category (25-500 only). 

Stakeholders expressed a concern that limestone contactors are presently not widely in use. 

Inhibitors 

The other approach to passivation for corrosion control is to use inhibitors. These are 

usually phosphate or silicate based. The principal type of phosphates used are orthophosphates; 

all are measured as orthophosphate as residual. Polyphosphates have a record of successful 

corrosion suppression in some waters. but in others they can increase corrosivity. 

Polyphosphates are primarily used as sequesterants. The chemicals are not dangerous, have a 

long shelf life. and are highly soluble. Small systems would be able to use small tanks and feed 

pumps. Systems should be aware. however, that tanks containing a phosphate-rich solution may 

experience some biological growth. Consequently, routine cleaning would be recommended. 

Another potential problem with inhibitors is that when first added, previously corroded material 

may be released (EPA 1992). 
Aeration 

Aeration removes carbon dioxide, which directly affects pH and dissolved inorganic 

carbon (DIC), the parameters that most influence lead and copper solubility. As a result, aeration 

can be an effective corrosion control strategy, presuming the initial pH and DIC are appropriate. 

A suitable water must have a significant carbon dioxide concentration and a corresponding 

relatively low pH. Carbon dioxide concentrations less than about 4to 10 mg/L CO, are not 

suitable for aeration. Mineral precipitation brought about by water quality changes resulting from 

aeration may present operational constraints under some conditions. Aeration produces 

consistent water quality and may be advantageous to smaller utilities because of relatively low 

costs and simple operational and maintenance needs (Lytle et al, 1998). 

ComplianceTechnolopies for Inorpanics 

Activated Alumina 

In the application of activated alumina (AA) for treatment of inorganics such as arsenic, 

fluoride and selenium. the pH must be lowered to the optimal range. When treated with an acid 

solution, alumina is strongly positively charged and will select highly for fluoride (F-), selenium 

species @eo,’-, HSeO,”). and arsenic ( H,AsO,-). Activated alumina displays a selectivity 

sequence, which refers to an ordcr in u hich ions are preferred by the alumina. Table 9.2 in 

Water Quality and Treatment ( .\\\’\I A 1990) shows the most preferred ions (i.e. those with the 

highest separation factors) at thc tcrp ot the table and the least preferred ions at the bottom. The 

greatest adsorption capacit! tor tluoridc occurs at pH 5.5. The greatest adsorption capacity for 

arsenic occurs at approsimalcl\ k!\\ccn 5.5 to 6.0 (Rosenblum 1984). To lower the pH, systems 

would have to use acids. \$ hich ni+ trr. problematic for small systems, since some degree of 

oversight would be requircJ II~cn\urc that the pH adjustment chemicals are added without 

causing significant water ctiLmi \Inprohlcrns. However, many small systems have only parttime operators. Small s>’wni\hwlJ also be concerned that it may be necessary to raise the pH 

after treatment to avoid corrclwvi prc+lcms. In addition. chemicals involved in the regeneration 

process (sodium hydrosidc 3rd wlturic acid) may be difficult for small system operators to 

handle. Consequently. small \! \tern\ \\ill likely need to regenerate the media off-site or dispose 

of the spent media rather than rcgcncrrttc it. AA media will likely pass toxicity tests (in the case 

of arsenic) and therefore \\ill be wiIat71e for landfilling (EPA 1998a). Small systems should also 

be concerned about highl! conccmr3Icd \vaste streams that can be produced. Spent regenerant 

from arsenic treatment cannot IihcI! bc discharged to a sanitary sewer without pre-treatment. 
. 

-

Coapulation/filtration -

Coagulatiordfiltration (C/F) units are available as package plants, however, it may not be 

advisable to install a C/F unit solely for inorganics removal. It may be a relevant technology if 

the raw water is also high in turbidity. Stakeholders mentioned that some manufacturers are 

making C/F units solely for arsenic removal. Stakeholders also expressed concerns about solids 

handling. For instance, disposal of arsenic contaminated sludge may be an issue, especially if it 

is deemed hazardous. Sludges are evaluated by the toxicity characteristic leaching procedure 

(TCLP) to determine if a sludge should be classified as hazardous. Sludges from four different 

water treatment plants were evaluated (Bartley 1992) for a variety of inorganic contaminants, 

including arsenic. One plant had a C/F process, one plant had a C/F and LS process, and two had 

LS processes. All TCLP extracts were considerably below the current criterion (5 mg/L of 

arsenic) for being designated a hazardous waste. 

Lime softeninp, 

Lime softening (LS), like coagulatiodfiltration, is not advisable solely for inorganics 

removal. However, if systems have hard water and inorganics problems, LS would be 

recommended as a compliance technology. Stakeholders agreed with this approach. Arsenic 

TCLP extracts from the LS sludges (from the study mentioned above) were also well below the 

criterion for being designated a hazardous waste. 

Ion exchange 

In considering application of ion exchange (IX) for inorganics removal, it is important to 

understand what the effect of competing ions will be, and to what extent the brine can be 

recycled. Similar to activated alumina, ion exchange exhibits a selectivity sequence, which 

refers to an order in which ions are preferred. Table 9.2 in Water Quality and Treatment 

(AWWA 1990) shows the most preferred ions (i.e. those with the highest separation factors) at 

the top of the table and the least preferred ions at the bottom. Barium, lead and copper are highly 

preferred cations. Sulfate competes with both nitrate and arsenic, but more aggressively with 

arsenic in anion exchange. The presence of TDS also impairs aresenic removal. Source waters 

with TDS levels above 500 mg/L and sulfate levels above 120 mg/L are not amenable to IX 

treatment (EPA 1998a). Spent regenerant is produced during IX bed regeneration and this spent 

regenerant may have high concentrations of sorbed contaminants and can be expensive to treat 

and/or dispose. Research has been conducted to minimize this effect: recent research on arsenic 

removal has shown that the brine can be reused as many as 25 times (Clifford 1998). Though ion 

exchange (IX) is an affordable. effective treatment technology for most inorganics, IX does not 

appear to be effective in removing antimony. In a bench scale study of ion exchange a removal 

of only 40 percent was obtained from an influent antimony concentration of 120 ug/l after 

processing 700 bed volumes (EPA 1990). The charges on a ion also effect the removal 

efficiency. For instance. ion exchange will remove arsenic (V), but won't remove arsenic (111), 

because the predominant species in natural water is uncharged. 

I 
Reverse osmosis 

A concern with reverse osmosis (RO) for inorganics treatment is that if the full stream is 

treated, then most of the alkalinity and the hardness would also be removed. In this case, posttreatment may be necessary to avoid corrosion problems. If feasible, a way to avoid this issue is 

to blend the water rather than treat the full stream. The amount of water that is rejected is also an 

issue with RO. Discharge concentrate can be between 10 and 50 percent of the influent flow 

(EPA 1998a). For that reason it may not be an appropriate technology for all parts of the U.S. 

RO involves passing water through a semi-permeable membrane by forcing the water from the 

concentrated solution side to the dilute solution side. Any contaminant that cannot dissolve into 

the membrane and pass into the permeate will be rejected by the RO membrane. Most inorganic 

contaminants of interest are rejected by the membrane and will be retained in the concentrate. 

Because of the small pore size, RO can remo\re both As(II1) and As(V). However, as with the 

other treatment technologies, RO removes As(V) to a greater degree than As(II1). Consequently 

pre-oxidation will improve removal efficiencies. For asbestos removal, RO and ultrafiltration 

techniques have problems with asbestos fibers accumulating on the membrane surfaces. 

Conventional flushing techniques may not be effective. 

Oxidation 

Several oxidants are availablc tor precipitating inorganics from drinking water, including 

chlorine. ozone. chlorine dioxide and pcrnianganate. In general, inorganics removal by oxidation 

involves the conversion of the contaminant to a higher valence state which may be less soluble 

and subject to precipitation. The osidiicd inorganic can then be removed by clarification andor 

filtration. However, oxidation of c~midcis a physical break-up. Oxidation has been evaluated 

for cyanide removal and the oxidants hhrch have been evaluated include chlorine and ozone. 

Bench and pilot evaluations of chlorinc ohidation were performed on wastewaters where cyanide 

concentrations and oxidant dosages w ere higher than those typically encountered in drinking 

water treatment. The results indicate that chlorine oxidation could achieve significant cyanide 

removal. Oxidation with chlorine is not a new technology; it has been frequently applied in 

small ground water systems. Chlorine oxidation is fairly inexpensive and not difficult to 

implement. A concern with chlorinc. ho\seiw. is the formation of disinfection by-products, 

especially since the chlorination should he conducted at a pH greater than or equal to 8.5. The 

use of chlorine to oxidize cyanide results in the formation of cyanogen chloride. Chronic 

exposure to cyanogen chloride may hc as harmful as chronic exposure to cyanide at and above 

the MCL. Chlorine quickly and effectively oxidizes cyanide and cyanogen chloride in a process 

called alkaline chlorination. Alkaline chlorination oxidizes cyanide to harmless bicarbonate and 

nitrogen gas by using excess chlorine at pH values greater than at least 8.5. The higher the pH 

the faster the reaction proceeds. Alkaline chlorination is prescribed over simple chlorination 

because of the need to destroy cyanide and cyanogen chloride as quickly as possible. 
Corrosion control 

In addition to preventing dissolution of lead and copper, corrosion control is relevant for 

inorganics removal because asbestos and cadmium can also be released from distribution 

systems. Corrosion control would minimize this release. Please refer to Section 5.2.1 for 

information on corrosion control technologies. In some cases where corrosion control is not 

possible, the only alternative may be to replace the piping. 

Direct filtration 

Direct filtration is a compliance technology for asbestos removal and can achieve 95% 

removal. In the application of this technology, proper chemical pretreatment is necessary. The 

chemical treatment may consist of conditioning the feed water with alum or iron coagulants and 

addition of polymers prior to filtration. The chemicals, when so added, destabilize the suspended 

asbestos particles in the water making them easier to remove in the filter. Higher asbestos levels 

in plant effluents are associated with poor destabilization of particles in the water and filter 

breakthroughs (EPA 1986b). 

Diatomaceous earth filtration 

Diatomaceous earth filtration is a compliance technology for asbestos removal and 

capable of 95% removal. Improved remot.al of asbestos fibers has been obtained with a two-step 

pre-coating procedure. A coarse grade of diatomite is first applied. A second pre-coat of a finer 

grade of diatomite that has been conditioned Lvith alum or an anionic polymer is then applied. 

Similar conditioning of the diatomite used tor body feed, by the continuous addition of a 

polymer to the raw water. also improves the fiber removal efficiency (EPA 1986b). 

Granular activated carbon 

Granular Activated Carbon ( GrIC ) is a compliance technology for treatment of mercury. 

GAC columns are used in water treatmcnt systems primarily for the removal of organics by 

adsorption and are particularly effecti\pe in removing those organics which contribute to taste and 

odor problems in drinking water. LIigh rcmo\,al efficiencies of mercury have been obtained with 

GAC and usually the capacity of GIIC for organic mercury is greater than its capacity for 

inorganic mercury (EPA 1984b). 

' Electrodialvsis reversal 

Electrodialysis reversal (EDR) is a compliance technology for barium, selenium and 

arsenic. In the removal of arsenic. fairly high recoveries can be obtained by using an internal 

brine recycle system (EPA 1998a). EDR can be quite expensive to run because of the energy it 

uses. However, because it is generally automated and allows for part-time operation, it may be 

an appropriate technology for small systems. 
POU Reverse Osmosis and Ion Exchange 

POU Reverse Osmosis (POU-RO) andor Ion Exchange (POU-IX) units are affordable 

compliance technologies for antimony, lead, arsenic, barium, beryllium, cadmium, chromium, 

copper, fluoride, selenium and thallium. For antimony, the only compliance technology listed 

for the smallest size category is POU-RO. POU units essentially use the same technology 

concepts as in centralized treatment, and so the comments regarding the treatment technologies 

made above also apply for POU treatment. Waste disposal is not likely to be an issue with POURO (please refer to Section 6.2). POU-RO units need to be provided with a means of 

discharging reject water to a drain; the reject water will likely be dilute enough to discharge 

directly into a drain. The EPA Drinking Water Research Division (DWRD) conducted POU 

studies in Alaska and Oregon where POU-RO and POU-IX were demonstrated to be viable 

treatment alternatives. DWRD entered into a cooperative agreement with San Ysidro, New 

Mexico to study POU-RO-removal of arsenic, fluoride and other contaminants. Again, POU 

units were shown to be effective. Since the conclusion of the San Ysidro study, the village has 

assumed ownership of the units and is now responsible for operating and maintaining the units 

(EPA 1998a). 

Section 5.3 Small Svstems ComDIiance Technolow List 

Compliance Technologies for Inorganic Contaminants tIOCS) 

Table 5.1 contains the technologies that have been identified as compliance technologies 

for at least one IOC. The table contains the same structure as other tables with a list of 

limitations that are contained in the footnotes and operator skill level and raw water quality 

issues for general operation of the technology. 

Table 5.1: Technologies for IOCs 

Unit Limitations Operator Skill 

technology (see footnotes) Level Required 

1. Activated (a) Advanced 

Alumina (b) concentrations will affect run length 

2. Ion (') Intermediate Ground waters with low total dissolved 

Exchange , solids. Competing ion concentrations 

(W will affect run length. Water should be ' low in solids to avoid fouling the resin. 
~~ ~~ 

3. Lime 

Softening 

4. Coagulation/ 

Filtration 

. 5. Reverse 

Osmosis (RO) 

6. Alkaline 

Chlorination 

7. Ozone 

Oxidation 

8. Direct 

Filtration 

9. 

Diatomaceous 

earth filtration 

10. Granular 

Activated 

Carbon . 

11. 

Electrodialysis 

Reversal 

12.POU-IX 1 

13.POU-RO I 

14. Calcium 

Carbonate 

Precipitation 

15. pH and 

alkalinity 

adjustment 

(chemical feed) 

(d) Advanced Hard ground and surface waters. 

(e) Variable source water quality may 

('1 make LS too difficult. 

(g) Advanced Can treat wide range of water quality 

(h) 

(I) Advanced Surface water usually require pre­

(') filtration 

(7 ~~ 

(I) Basic All ground waters 

(") 

Intermediate All ground waters 

5 

(") Advanced Needs high raw water quality 

(P) Intermediate Needs very high raw water quality 

(q) Basic Surface waters may require 

prefiltration 

Requires prefiltration for surface water 

(r) 1 Basic Same as Technology #2 

(r) 1 Basic Same as Technology #5 

Waters with high levels of alkalinity 

and calcium 

(') Basic All ranges 
16. pH and (') Basic Waters that are low in iron and 

alkalinity turbidity. Raw water should be soft 

adjustment and slightly acidic. 

(limestone 

contactor) 

17. Inhibitors 1 (") Basic All ranges 

- ~ 

("1 I

18. Aeration (Y) Basic Waters with moderate to high carbon 

dioxide content. 

Limitations Footnotes to the TechnologyTables for IOCs 

a Chemicals required during regeneration and pH adjustment may be difficult for small 

systems to handle. 

May create highly concentrated waste streams. 

Disposal of regeneration solution containing high concentrations of undesired ions may 

be problematic. 

Softening chemistry may be too complex for small systems. 

e Operation and maintenance of lime feeders and lines carrying lime slurry may be too 

complex for small systems. 

'In LS, there is a potential for precipitation of excess lime in filter beds and formation of 

calcium carbonate deposits within filters. 

6 It may not be advisable to install coagulatiodfiltration solely for inorganics removal. 

Solids handling may be an issue. For instance, disposal of arsenic contaminated sludge 

may be an issue, especially if deemed hazardous. 

' If all of the influent water is treated, then most of the alkalinity and hardness would also . 

be removed; post-treatment corrosion control will be necessary. 

J Amount of water that is rejected can be substantial. RO may not be appropriate for all 

parts of the U.S.

'For asbestos removal, RO has problems with asbestos fibers accumulating on the 

membrane surfaces. Conventional flushing techniques may not be effective. ' pH must exceed pH 8.5 to ensure complete oxidation without build-up ofcyanogen 

chloride 

With alkaline chlorine oxidation, there is the potential for formation of disinfection byproducts. 

" Conditioning the feed water with alum or iron coagulants and addition of polymers prior 

to filtration may be necessary for asbestos removal (EPA 1986b). 

O Two-step precoating procedure may be necessary for asbestos removal. A coarse grade 

is first applied. A second coat conditioned with alum or an anionic polymer may be necessary 

(EPA 1986b). 

P Continuous addition of a polymer to the raw water may be necessary to improve 
asbestos fiber removal efficiency (EPA 1986b). 

q Usually, the capacity of GAC for organic mercury removal is greater than its capacity 

for inorganic mercury removal (EPA 1984b). 

When POU devices are used for compliance, programs for long-term operation, 

maintenance, and monitoring must be provided by water utility to ensure proper performance 

(see Section 1.4). 

Small systems should be aware of the complexities inherent in using lime and soda ash 

systems. These methods require a high degree of operator attention because the calcium 

carbonate plugs bins, tanks, pumps and piping (EPA 1992). 

In operating a sodium hydroxide feed system, employees may have to handle the strong 

base. 

" This approach may cause a btdd-up of precipitate in consumers' hot water heaters. 

" This technology is recommended primarily for the smallest size category. 

Tanks containing a phosphate-rich solution may experience some biological growth. 

Routine cleaning is recommended. 

When first added, previously corroded material may be released (EPA 1992). 

Y Any of the first five aeration technologies listed for volatile organic contaminants can be 

used. 

Section 1.3 indicated that EPA would identify affordable compliance technologies for 

those existing regulations where small system variances or variance technologies are not 

prohibited by the SDWA. There are statutory prohibitions against small system variances or 

variance technologies for 13 of the 1 7 IOCs. Table 5.2 contains the compliance technologies for 

the four IOCs where affordability was considered. Affordability only plays a role in removing 

some of the options in the smallest size category. The technology costs are based on treatment of 

all of the water. The technologies that did not meet the affordability criteria in the smallest size 

category are also identified in the next column called other compliance technologies. These 

technologies may be affordable if the concentration of the contaminant is low enough that a 

portion of the influent stream can be treated and blended with an untreated portion to still meet 

the MCL. Systems and States should consider these options under those circumstances. Table 

5.3 contains the compliance technologies for the remaining thirteen IOCs where affordability 

was not considered due to statutory prohibitions (EPA 1998b). 

Gf 
Table 5.2: Compliance Technologies by System Size Category for those IOC NPDWRs where 

Affordability is Considered 

Compliance Technologies for System Size Categories 

Inorganic (Population Served) 

25 - 500 25 - 500 501 -3,300 3,301 - 10,000 

(afford) (other) (afford) (afford) 

Antimony 13 475 4, 5, 13 4, 5, 13 ~ 

Asbestos 8, 9, 15. 17 4 4, 8, 9, 15, 17 4,8,9, 15, 17 

Cyanide 2,6. 7 5 2,5, 697 

Contaminant 

Lead 2, 12, 13, 14, 15. 3.4. 5 2,3,4,5, 12, 13, 2,3,4,5, 12, 13, 

16, 17, 18 14, 15,16, 17, 14, 15, 16, 17, 

18 18 

Table 5.3: Compliance Technologies b\ System Size Category for those IOC NPDWRs where 

Affordability is Not Considered 

Compliance Technologies for System Size Categories 

Inorganic (Population Served) 

Contaminant 

25 - 500 501 - 3,300 3.301 - 10,000 

Arsenic 1,2,3.4.5.ll.l,.7 1,2,3,4,5,11,12, 1,2,3,4,5,11,12, 

13 13 13 

Barium 2. 3.4. 5. 11. 12. 13 2.3,4,5,11,12,13 2,3.4.5,11,12,13 

Beryllium 1,2. 3.4.5. 12. 13 1,2,3,4, 5, 12, 13 1,2,3.4,5, 12, 13 

Cadmium 2. 3.4.5. 12. 1-T 2. 3,4, 5, 12, 13 2, 3,4. 5, 12, 13 

Chromium 3.3’.4.5. 12. 13 2.3 ”. 4, 5, 12, 13 2, 3 ”,4, 5, 12, 13 

Copper 2,3.4,5. 12. 13. 15. 2,3,4,5, 12, 13, 15, 2,3,4,5, 12, 13, 15, 

F1uoride 

16, 17. 18 

1. 5. 13 

16, 17, 18 

1. 5, 13 

16, 17, 18 

1 1,5, 13 

Mercury 3b,4b, 5b. 10 

Nitrate 2, 5, 11 2. 5, 11 2, 5, 11 
-- 

Nitrite 2, 5 1275 1275 

Nitrate + Nitrite 2, 5, 11 2, 5, 11 2,5, 11 

Selenium 1,2', 3, 4d,5, 1 Id, 13 1,2', 3, 4d,5, 1 Id, 13 1,2', 3, 4d,5, 1 Id, 13 

Thallium 1.2, 12 1,2, 12 1,2, 12 

Footnotes for Table 5.3 : Compliance Technologies for IOCs (affordability not considered) 

a Compliance technology for Chromium '111 only. 

Compliance technologies only when influent mercury concentrations s 10 pg/L. 

Compliance technology for Selenium VI only. 

Compliance technology for Selenium IV only. 

Following is a listing of technologies that EPA did not list as compliance technologies. 

However, EPA is monitoring the development of these technologies and may list them as 

compliance technologies in future updates of this guidance. 

BioloPical denitrification 

For nitrate removal, another appropriate technology may be biological denitrification. In 

biological denitrification, micro-organisms are fed some form of carbon, and use the nitrate as an 

electron acceptor instead of oxygen. The micro-organisms reduce the nitrate to nitrogen. 

Though this technology has been used in wastewater treatment, its use in the United States in 

water treatment is limited. The primary reason is that there is concern that since bacteria are 

being used to treat the water, there is a potential for bacterial contamination of the water supply. 

Nanofiltration. ultrafiltration and microfiltration 

Asbestos: 

The MCL for asbestos is 7 million fibedliter and refers only to those fibers longer than 

10 microns (EPA I99 1b). For particles of that size, reverse osmosis, nanofiltration, 

ultrafiltration and microfiltration would be effective removal technologies. The membrane pore 

size for microfiltration varies from approximately 0.1 to 1.O microns (AWWA 1998); therefore, 

the tecly~ologycan be expected to remove asbestos fibers larger than 10 microns. For asbestos 

removal, membrane techniques, however, have problems with asbestos fibers accumulating on 

the membrane surfaces. Conventional flushing techniques may not be effective. The issue 

requires further research. 
-- 

Arsenic: 

Nanofiltration (NF) membranes have pore sizes that vary from approximately 0.00 1 

microns to 0.005 microns. Because of the small pore size, NF can remove both As(II1) and 

As(V), but as with the other treatment technologies, NF removes As(V) more effectively. The 

small pore size, however makes NF membranes more prone to fouling than ultrafiltration or 

microfiltration membranes. The application of NF for surface water treatment is typically not 

accomplished without extensive pretreatment for particle removal and possible pretreatment for 

dissolved constituents to prevent fouling (EPA 1998a). NF can be operated at lower pressures 

then reverse osmosis, which translates into lower operation and maintenance costs. However, a 

recent study with arsenic removal revealed that the removal efficiency dropped significantly 

during pilot-scale tests where the process was operated at more realist recoveries. When the 

membrane unit was operated at a recovery of 65%, the arsenic removal efficiency dropped to 

65% and when the recovery was increased to 90%, the arsenic removal efficiency dropped down 

to 16% (Chang 1994). 

POU Activated Alumina Units 

Activated Alumina (AA) units are often used for fluoride removal and are also applicable 

for arsenic and selenium removal. Since the greatest adsorption capacity occurs at pH 5.5 for 

fluoride, and between 5.5 and 6.0 for arsenic, and the pH will not be adjusted in a POU unit, the 

removal efficiency will not be optimum. This implies that the exchange/adsorption capacity of 

the activated alumina will be reached in a shorter time, and the spent cartridge will need to be 

replaced more often. If, after investigation, EPA determines that this is not a major issue, POU 

AA units will be added as compliance technologies in the next update of this list. 

POU Ion ExchanFe and Reverse Osmosis Units for Nitrate 

Ion exchange and reverse osmosis are appropriate technologies for nitrate removal. If 

they are used as POU devices, it is important to educate consumers as to potential health effects. 

Since POU devices do not treat all the water taps in a house, there is a potential health risk of 

household residents drinking untreated water. Nitrate, as mentioned previously, is a potential 

hazard to young infants; serious and occasionally fatal poisonings in infants have occurred 

following ingestion. Households need to be informed about the importance of meeting 

replacement schedules for media, cartridges, filters. and modules associated with POU systems. 

Households also must be careful not to use untreated water to make infant formula. Almost all 

. established cases of water related nitrate-induced methemoglobinemia in the United States have 

resulted from the ingestion of private well water used to make infant formula. Stakeholders 

suggested that EPA investigate the feasibility of public awareness projects such as using print. 

radio and television media anh public forums. Public outreach would, however, have significant 

costs and may offset any savings of using POU devices. 
-- 

POE Units 

POE units are relatively expensive, and not likely an affordable technology for small 

systems. In addition, waste disposal issues remain with POE units. The disposal of the brine or 

concentrate stream may be problematic. In addition, EPA needs to investigate if the usage of a 

Limestone contactor after a reverse osmosis unit will be adequate for corrosion control of internal 

plumbing. 

References 

American Water Works Association and American Society of Civil Engineers. Water Treatment 

Plant Design. Third Edition. McGraw-Hill. 4 998. 

American Water Works Association. Water Oualitv and Treatment. A Handbook of Community 

Water Su~plies.Fourth Edition. McGraw-Hill. 1990. 

Bartley, C.B., Colucci, P.M. and Stevens, T. “The inorganic chemical characterization of water 

treatment plant residuals”. EPA/600/SR-92; 117, U.S. Environmental Protection Agency, 

Cincinnati. 1992. 

Benefield, L.D. et al., Process Chemistrv for Water and Wastewater Treatment, Prentice-Hall, 

1982. 

Black and Veatch Consulting Engineers. “ Direct Filtration of Lake Superior Water for 

Asbestiform Fiber Removal”. US. Environmental Protection Agency, EPA-670/2-75-050a, 

1975. 

Chang, S.D., Ruiz. H., Bellamy, W.D. et al. “Arsenic Removal by Enhanced Coagulation and 

Membrane Technology. Proceedings of the 1994 American Water Works Association Annual 

Conference”. American Water Works Association, New York, 1994. 

Clifford, D., G. Ghurye and A. Tripp (1998). “Arsenic removal by Ion Exchange With and 

Without Brine Reuse,” AWWA Inorganic Contaminants Workshop, San Antonio, TX, February 

23-24. 1998. 

Kirmeyer. G.J. “Seattle Tolt Water Supply Mixed Asbestifcrm Removal Study”. U.S. 

Environmental Protection Agency, EPS-600/2-79-125, 1979. (Kirmeyer 1979a) 

Kirmeyer. G.J. “Seattle Tolt Water Supply Mixed Asbestiform Removal Study. Appendices B 

and C’. U.S. Environmental Protection Agency, EPA-600/2-79-153, 1979. (Kirmeyer 1979b) 

Logsdon, G.S. “Water Filtration for Asbestos Fiber Removal”. U.S. Environmental Protection 

Agency, EPA-600/2-79-206, 1979. 
-- 

Lytle, D.A.. Schock, M.R., Clement, J.A., Spencer, C.M. “Using Aeration for Corrosion 

Control”, Journal AWWA, March 1998. 

Rosenblum, E.R. and D.A. Clifford (1984). The Eauilibrium Arsenic Capacitv of Activated 

Alumina, PB 84/10 527, NTIS, Springfield. 

USEPA. “Technology and Costs for the Removal of Nitrates from Potable Water Supplies”. 

Prepared by V.J. Ciccone & Associates, Inc. August 1984 (EPA 1984a). 

USEPA. “Technologies and Costs for the Removal of Mercury from Potable Water Supplies”. 

Prepared by V.J. Ciccone & Associates, Inc. December 30, 1984 (EPA 1984b). 

USEPA. “National Primary and Secondary Water Regulations; Fluoride; Final Rule.” Federal 

Register. Vol. 51, No. 63, p. 11396. April 2, 1986 (EPA 1986a). 

USEPA. “Technologies and Costs for the Removal of Asbestos from Potable Water Supplies”. 

Prepared by V.J. Ciccone & Associates, Inc. February 5,1986 (EPA 1986b) 

USEPA. “Limestone Bed Contactors for Control of Corrosion at Small Water Utilities” 

February 1987. 

USEPA. “Technologies and Costs for the Removal of Phase V Inorganic Contaminants from 

Potable Water Souces.’‘ Prepared by Malcolm Pirnie, Inc. January 1990. 

USEPA. “Maximum Contaminant Level Goals and National Primary Drinking Water 

Regulations for Lead and Copper; Final Rule.” Federal Register. Vol. 56, No. 110, p. 26460. 

June 7, 1991 (EPA 1991a) 

USEPA. “National Primary Drinking Water Regulations; Final Rule.” Federal Register. Vol. 

56, No. 20. p. 3526. January 30.1991. (EPA 1991b) 

USEPA. “Lead and Copper Guidance Manual-Volume 2: Corrosion Control Treatment”. 

Prepared by Black & Veatch and Malcolm Pirnie, Inc. September. 1992. 

USEPA. ‘’Draft Technologies and Costs for the Removal of Arsenic from Potable Water 

Supplies”. Prepared by International Consultants, Inc. July 1998 (EPA 1998a). 

USEPA. “Variance Technology Findings for Contaminants Regulated Before 1996“. EPA 815-

R-98-003. Office of Water. September 1998. (EPA 1998b). 
6. SMALL SYSTEMS COMPLIANCE TECHNOLOGIES FOR RADIONUCLIDES 

c 

I . 

I -

Section 6.1: Background 

The applicability of particular treatment technologies to the removal of radionuclides 

from drinking water depends significantly on the chemical and physical characteristics of the 

contaminants involved and the site specific characteristics of the water system, e.g., source water 

quality and water system size. The considerations that determine feasibility include: high 

removal efficiency, general geographic availability and applicability (e.g., climate 

considerations) of the technology, cost, service life, and co-treatment compatibility. 

The removal strategies for radium, gross-alpha emitters, and total beta and photon 

emitters exploit the chemistries of the individual contaminants, as with any removal contaminant 

removal strategy. The chemical properties of the contaminant to be removed, e.g., speciation, 

solubility, tendency to sorb, etc.. have a deciding influence on the ehoice of the best treatment 

strategy. For example, some contaminants occur as either cations or anions depending upon the 

source water conditions, e.g., pH. the presence of other complexing ions, including dissolved 

organic compounds, etc. Thus. the choice of cation versus anion exchange treatment may depend 

upon the site specific situation. As another relevant example, for coagulatiodfiltration treatment 

processes to be effective for removing elevated gross alpha levels caused by uranium, uranium 

must sorb to the floc or precipitate before settling or filtration. Highly efficient removal will 

only occur for those uranium species that sorb significantly under the site specific conditions of 

the source water as affected bj. the treatment process. For reverse osmosis treatment, the water 

chemistry of the contaminants in question is less important since the removal mechanism tends 

to remove both cations and anions and does not involve sorption. 

Radionuclides occur naturall) as trace elements in rocks and soils as the result of the 

radioactive decay of the uranium-238 (U-238) and thorium-232 (Th-232). Of the U-238 and Th232 decay series. radon-232. radium-226. radium-228, U-238, and U-234 are the most common 

in ground water (Zapecza and S;l;lho 1986). The other naturally occurring radionuclides are not 

present in significant amounts in ground water, because of their environmental immobility and/or 

short half-lives. The naturally occurring radionuclides of the uranium-238 decay series 

(uranium-238, radium-226. and radon-222) are responsible for the majority of radiation exposure 

associated with drinking water (e.g.. Lowry and Lowry 1988, EPA 1991a). Radium-228 can also 

have significant occurrence. Of these. only radium-226 and -228 currently have National 

Primary Drinking Water Regulations. Total beta and photon emitter activity will be discussed 

only briefly since most are anthropogenic and their occurrence is very site specific'. Although 

' Beta and photon activity is usually the result of releases from nuclear facilities. Since 

releases from these facilities are strictly controlled, occurrence is rare. As such, total beta and 

photon activity is of concern to only a few drinking water supplies. 
uranium’ comprises the majority of “true total alpha activity” in surface waters (i.e., total alpha 

activity without excluding radon-222 and uranium isotopes), it is exclude by definition from 

gross alpha activity. This being the case, and since radium-226 primarily comprises gross alpha 

occurrence in ground waters, radium will be the focus of the remainder of this discussion’. 

When planning removal strategies for radionuclides, it is important to understand that 

different isotopes of the same element (e.g., radium-226 versus radium-228) are chemically 

indistinguishable from the perspective of treatment (Clifford 1990). In other words, when 

planning treatment, “radium is radium”. 

Chemical Behavior of Radium 

Radium is primarily a ground water contaminant. Under oxidizing conditions (e.g., 

surface waters), it is very immobile. The sources of radium to ground water include dissolution 

of radium-bearing aquifer solids, “alpha-recoil3” of radium isdtopes from the aquifer solid matrix 

across the solid/water boundary (Hess et al. 1985), and desorption of radium from aquifer solids 

surfaces. Since radium itself is not very soluble in water and does not form strong complexes 

with common solutes found in aquifers, the alpha recoil process is important in that it can 

significantly increase the radium concentration above that due to dissolution from the aquifer 

material. The radium “liberated” by the alpha recoil process may then stay in solution or sorb to 

the aquifer matrix, where the fraction of radium in solution to that sorbed is determined by the 

local geochemical conditions of the aquifer. For a more detailed discussion of how local geology 

and geochemical processes control the occurrence of radium in aquifers, see, e.g., Hess et al. 

1985, Zapecza and Szabo 1986, and Michel 1991. In general, radium occurs at higher ground 

water concentrations under reducing conditions with high total dissolved solids content (Tanner 

1964, as cited in Zapecza and Szabo 1986, and Michel I99 1). 

Radium, though much less soluble, behaves in water analogously to calcium and 

’ Uranium was proposed for regulation in 1991. A final NPDWR for uranium is 

expected in the near future and will include a list of small systems compliance technologies. 

A revised Small Systems Compliance Technology list for gross alpha activity will be 

issued with the future updated NPDWR for radionuclides. 

’ Alpha-recoil refers to the recoil motion of the daughter product (the radium isotope, in 

this case) resulting from the high energy ejection of the alpha particle during the alpha-decay of 

the parent isotope, which was originally embedded in the aquifer solid phase. Analogous to the 

recoil energy of a gun (Michel 1991), the high speed ejection of the alpha particle results in 

recoil of the progeny radium isotope, imparting enough energy to eject it across the solid/water 

interface into the ground water phase. This mechanism results in the enhanced solubility of the 

radium isotope (Hess et al. 1985). 

L 
magnesium (all are alkaline earth metals, group HA), so water softening processes like ion 

exchange and lime softening tend to remove radium also. Like the other alkaline earth metals, 

radium remains a divalent cation (Ra2+(,q,)up to the higher end of pH values normally found in 

drinking water sources. In other words, radium does not significantly hydrolyze water (form 

hydroxides or oxides) at ambient pH levels. This greatly simplifies the water chemistry of 

radium. One treatment strategy consequence of this is that cation exchange is usually the most 

appropriate ion exchange type. 

It is important to keep in mind that the radium ion is a problem at picogram (pg) per liter 

levels’, whereas calcium concentrations of 100 mgL are not unusual. To put this in perspective, 

under those conditions, for every radium ion present in solution, there would be 10”, or one 

hundred billion, calcium ions competing in the chemical processes2that are exploited in water 

softening. Fortuitously, radium preferentially sorbs relative to calcium or magnesium during 

water softening processes to an extent that allows good radium removals. During lime softening, 

which involves the precipitation of calcium carbonate and magnesium hydroxide, radium coprecipitates efficiently enough to achieve good removals (Clifford 1991). These and other 

treatment processes will be discussed in more detail later in this chapter. 

Another consequence of radium’s tendency to strongly sorb is that radium tends to 

associate with suspended particulate matter. Colloid and micro-particulates in ground water 

sources can include silica. high molecular weight organic matter, clays, and oxides precipitates of 

Mn, Fe. and Al. Depending on the local chemical and physical conditions, a variable amount of 

radium may be removed during the filtration removal of this suspended material. Unfortunately, 

the average removal efficiency from simple filtration is often too low to be very useful (Clifford 

1991). 

Section 6.2: Evaluation of Technologies 

Based on the properties of radium discussed above and the other criteria affecting 

treatment technology selection, the treatment technologies evaluated for radium removal were 

limited to: ion exchange (IE), point-of-use IE, point-of-entry IE, reverse osmosis (RO), point-ofuse RO, point-of-entry RO, lime softening (LS), greensand filtration, co-precipitation with 

barium sulfate, selective sorbents, electrodialysis/electrodialysisreversal (ED/EDR), and preformed hydrous manganese oxides (HMOs). For the removal of gross alpha emitters where 

radium comprises most of the activity, these same technologies would apply. For the removal of 

’ 1 pCi/L of radium roughly corresponds to 1 pg/L. 

For a discussion of competitive sorption, see Snoeyink 1990, p.788. Radium has the 

largest atomic weight and hydrated ionic radius of the alkaline earth metal cations, which greatly 

increases its tendency to sorb to ion exchange resins relative to the other alkaline earth cations, 

including Ca” and Mg”. 

71 
gross alpha activity caused by radionuclides other than the radium, which can include a variety of 

contaminants, technologies should be evaluated on a case-by-case basis. This is also true for 

total beta and photon emitter activity. However, ion exchange (IE). point-of-use IE, point-ofentry IE, reverse osmosis (RO), point-of-use RO, and point-of-entry RO were determined to be 

robust enough to merit a general evaluation. 

The best available technolagies (BATs) from the 1991 radionuclides proposed rule (EPA 

1991a) were evaluated as small systems compliance technologies. The table below lists the 

MCLs and the 1991 proposed BATs for the currently regulated radionuclides. 

MCLs and BATs for Regulated Radionuclides 

Contaminant 

combined radium-226 and radium228 

gross alpha particle activity 

total beta particle activity and 

photon activity, average annual 

concentration 

Ion Exchanpe 

MCL (1976) -BAT (Proposed 1991) 

5 pCi5 Ion exchange (IE), lime softening 

(LS), reverse osmosis (RO) 

15 pCi/L RO 

4 milliredyear IE, RO 

The ion exchange (IS)process and general small systems concerns regarding the use of 

ion exchange are discussed in Chaprcr 3. IX may be used to selectively remove radionuclide 

ions from drinking water. c.6..thc \vcll known application of sodium ion exchange softening for 

removing radium. As discussed in Chapter 3. IX treatment may be readily adapted for use by 

small systems (NRC 1997) and may bc used in a point-of-use and point-of-entry mode. The 

effluent must be regularly monitored and/or the resin must be regenerated on a sufficiently 

frequent basis to ensure that breakthrough has not occurred. However, the units may be 

controlled automatically, so operator requirements may not be overly time intensive. 

Determination of regeneration frequency and trouble-shooting do require a skilled operator 

(Clifford 1990a). It should be noted that disposal can be expensive in the case of concentrated 

radionuclides. 

Wastes generated by IX treatment include rinse and backwash water and, eventually, the 

resin itself. The rinse and backwash liquid waste includes brine, radium, and any other 

contaminants removed by the process. The contamination of the exhausted resin depends upon 

its loading capacity and the degree of use since the last regeneration (EPA 1994). Disposal 

issues specific to radium are discussed below. 
Point-of-entry and point-of-use softening units are common and have been shown to be 

consistent and effective in removing radium (AWWA-ASCE 1998, Clifford 1991a. Clifford 

1991b). The general concerns regarding monitoring and performance that were discussed in 

Chapter 3 apply here. Disposal of point-of-entry regenerant wastes are issue that remains to be 

resolved before this technology will be listed as a small systems compliance technology. Point-

' of-use softeners may be regenerable or disposable. Water systems must take care to ensure that 

proper radium removal performance is being maintained through monitoring and/or maintenance. 

If drain disposal of regenerant wastes from point-of-use softeners to sanitary sewers is possible, 

this technology may be an attractive option for small water systems. If disposal is not an option, 

non-regenerable resins may be an attractive option. 

Cation Exchanve 

Cation exchange resins are used to remove undesired cations fiom water by exchanging 

them with protons (H-).sodium ions (Na'), or, in the case of sodium restrictions, potassium ions 

(K+). Cation exchange is oftcn used to reduce hardness through the removal of calcium and 

magnesium cations, and thus is an efficient treatment for radium. Cation exchange is also a 

treatment of choice for cationic bet3 and photon emitters. 

As discussed in thc introduction to this chapter, radium preferentially sorbs relative to 

calcium and magnesium. Studich indicate that sodium cation exchange can remove 80 - 98% of 

radium (Brink et al. 1978. as cited in Clifford 1990b. USEPA 1983, USEPA 1992). Significant 

radium breakthrough \!as rcpmcJ onl! after significant hardness breakthrough occurred 

(Clifford 1990b). Since trcatcJ \s.mr ISoften blended with some raw water (commonly 30 to 

50% blending) to reduce concw\ it! in the effluent after softening, the radium influent levels 

must not be so high that the blcnJing process raises the radium effluent levels above the MCL. If 

the radium influent level5 arc ttbtt high. corrosivity reduction other than blending or a treatment 

other than softening must h..UX-J 

Weak acid cation ( \\ 1 cuhange resins may be used to remove radium from ground 

water. For example. acid 11:\( rcbins may be used to exchange hydronium ion (H') for radium. 

The exchange process remcn CI h.irdncss. alkalinity, and total dissolved solids from the influent 

and is limited by carbonatc dLiilinit!. Acid elution can be used to regenerate the resin. 

Although acid WAC resin exhangers are more expensive than sodium exchangers, they should 

be considered when hardness and total dissolved solids reduction is desired along with radium 

removal. 

The liquid waste stream (rinse and backwash) volume produced by cation exchange for 

radium removal typicall~rranges between 2 and 10% of the product water volume. The radium 

concentration in the liquid waste depends upon the radium influent concentration, the volume of 

regenerant solution used, and the frequency of regeneration. An Iowa case study showed liquid 

waste radium levels between 1 IO and 530 pCi/L. Another showed an average and peak waste 

level of 23 and 160 pCi/L, respectively. At the latter facility, the exhausted resin accumulated a 
radium level of ca. 9 pCi/g (EPA 1994) 

Anion exchanpe 

A few studies have been conducted to specifically assess the effectiveness of anion 

exchange for “gross alpha” removal, where either uranium is not the dominant source or the 

speciation was not specified (EPA 1992). Removals between 85 and 95 percent can be achieved, 

depending on which alpha emitters are present and on the water quality. 

Lime Softening 

Lime softening (Benefield et al. 1990, EPA 1992, NRC 1997) can be used to remove 

radium from drinking water with removal efficiencies of 80 to 95%. This process involves 

inducing precipitation of calcium carbonate and magnesium hydroxide by increasing the pH of 

the treated water to ca. 10 through the addition of lime or lime-soda ash. The general process is 

discussed in more detail in Chapter 3. 

For surface water systems, lime softening technology is considered most feasible for 

large systems (those that serve more than 10,000 persons) because of the difficulties resulting 

from the combination of variable source water quality and the complexity of the chemistry 

involved. Changing water quality necessitates frequent monitoring and modification of the 

chemical dosage, creating the need for intensive oversight by a highly qualified operator. This 

requirement may be too burdensome for small surface water systems. 

For ground water systems. the relative uniformity in water quality makes lime softening a 

more feasible technology, since the required dosages are relatively constant. However, the 

operation and maintenance of lime feeders and the lines that carry the lime slurry to the treated 

water are not simple matters, and they may prove too difficult for part-time operators. Since 

many ground water systems are small, this limits the applicability of lime softening. 

Fortunately, small package plants with labor saving devices and remote monitoring/control 

features are becoming more common. making lime softening more accessible to small systems. 

The National Research Council (1 997) has suggested that while lime softening may be 

appropriate for small ground water systems serving fewer than 3,300 persons, those serving 

fewer than 500 should only use lime softening if they have a service contract or a satellite 

operation that would enable a qualified operator to monitor the treatment process on a regular 

basis. Since radium is typically found at higher levels only in ground waters, lime softening may 

be an appropriate radium removal option for many small systems. 

Wastes generated by lime softening include lime sludge, filter backwash liquid and 

sludge, and sludge supernatant. Typical radium concentrations in waste products are reported to 

range from 1,980 pCi/L in the wet lime sludge, 6 to 9 pCi/g in the dried sludge, 6 to 50 pCi/L in 

the filter backwash liquid, and ca. 20 to 25 pCi/L in the sludge supernatant (EPA 1994). 
Reverse Osmosis (R0) 

The reverse osmosis process is described in Chapter 3 of this document. Reverse osmosis 

has been shown to be highly effective for removing inorganic contaminants, including heavy 

metals and radionuclides such as radium and uranium. RO can remove 87 to 98% of radium in 

drinking water. Similar removals can be achieved for alpha particle activity and total beta and 

photon emitter activity (EPA 1992, EPA 1998a). 

Historically, RO membranes have required high operating pressure, in excess of 400 psi, 

to provide adequate feed water recovery for brackish and fresh water supplies. However, recent 

advances in membrane technology have led to the development of membranes capable of 

operating at much lower pressures (100 to 200 psi). Low pressure membranes provide 

substantial savings in process electric energy. 

The performance of an RO system for radionuclide removal-depends upon a number of 

factors including pH, turbidity, irodmanganese content of the raw water, and membrane type. 

Design of a pretreatment system is dependent upon the quality and quantity of the feed water 

source and may include one or more of the following: pH adjustment, filtration, iron and 

manganese reduction, or additives for scale prevention. Existing treatment plants may already 

provide much of the pretreatment required, for example, coagulatiodfiltration for highly turbid 

surface water or iron removal for well waters. RO is adaptable to all systems sizes and can be 

cost effective for small systems. 

RO does not selectively remove dissolved contaminants. Therefore it is very effective for 

removing multiple contaminants in one step. 

RO systems produce very high quality water, removing 90 to >99% total dissolved salts 

from the feed water, leading to demineralized product water. Demineralized water has low 

alkalinity and can be corrosive. To reduce corrosivity in the product water, systems may by-pass 

some of the raw water and blend it with the permeate. raise the pH, or otherwise add alkalinity. 

The need for blending may be a factor in the selection of a RO system. In fact, the blending 

process can make an RO process more economical than complete treatment of all raw water. The 

fraction of the raw water to be treated will depend upon the removal efficiency of the selected 

RO membrane, the initial concentration of contaminants in the raw water, and the required 

effluent objective. 

The reject water from RO is the only waste generated. However, reject water is 

continuously generated during operation, so the volumes created are large compared to the 

amount of water treated. The radium concentration in the reject water depends on the radium 

concentration in the influent and the percent recovery of the operation. For example, if the RO 

unit removes 98% of radium and rejects 50% of the influent water, then the reject water will 

contain roughly two times the concentration of the influent water. Studies report ranges of ca. 8 

to 40 pCi/L of radium in the reject water (EPA 1994). 
Although point-of-use (POU) RO was not proposed as BAT in 1991 (see Chapter l), it 

appears to be a very promising small systems treatment option for inorganic contaminants 

removal (NRC 1997), including radium, since it is reliable, effective, and simple to use on the 

small scale (Clifford 1991a, Thomson and O'Grady 1998, EPA 1998~).A typical POU RO 

configuration for radionuclides removal would include a 5 micron pre-filter to remove 

particulates, a GAC filter to remove chlorine, taste, and odor, the RO unit itself, and a connection 

to the sink drain for reject water disposal. The discharge line requires an air gap to prevent a 

cross-connection between wastewater and drinking water. 

Since general POU concerns are described above, this section will focus on reject water 

disposal concerns. One of the primary advantages of POU RO is that reject water waste disposal 

is straightfonvard if drain disposal to a sanitary sewer is possible. Although the total mass or 

concentration of radionuclide contaminants discharged from the house would not significantly 

change when RO treatment is installed, the reject water does contain higher radionuclides 

concentrations than the untreated tap water. The actual degree of cencentration depends on the 

recovery percentage, as described above. Once the reject water sufficiently mixes with the other 

drainage water, the radionuclide levels will be diluted until they approach those in the untreated 

water. Since the drain water from a single tap is usually a small part of the drain water budget of 

the entire household, this dilution should occur very quickly. The table below shows the 

relationship between the YOincrease in radium concentration for the total household drainage 

versus the RO recovery percentage: 

I Percent Increase in Radium Concentration in Household Drainage versus RO Rejection Percentage I 1 YORecovery' I YO[Ral Increase' I Notes I 

50 

40 

5.0 

3.3 

1) 'Oh Recovery" = lOO*Volume of Product Water/ Volume ofTotal Water at 

Tap) 

2) '% [Ra] Increase" is the percentage increase in the concentration of 

radium in the total house drainage. !.e., for a recovery of 50% and an 

untreated water (influent) radium concentration of 10 pCi/L, the total 

house drainage would have an average concentration of 10.5 pCilL 

0.6 

The table assumes that drinking and cooking water comprises 5% of the total household water 

(EPA 1991) and that the rest of the water is returned to the drain. As the table shows, if the drain 

water is discharged to a sanitary sewer, the concentration of radionuclides reaching the waste 

water treatment plant should not be significantly affected by the addition of POU RO. Clifford 

(1 99 1a) reports a 15% recovery for spiral wound POU RO as typical. At this recovery, the reject 

water is concentrated by a factor of about 1.18 relative to the raw water and, extrapolating from 

the table. the increase in the average radium concentration in total household drainage is less than 

one percent. 

73 

7b 
l -

I * 

Stakeholders discussed the possibility of using POU RO with households connected to 

septic tanks. While the above analysis would indicate that this may be feasible, EPA (1994) does 

not suggest disposal of water treatment wastes into septic tanks. However, this suggestion is 

based on centralized treatment assumptions and may not cover POU RO scenarios. This issue 

deserves attention in the future. 

Technolopies for Radionuclide Removal Not ProDosed as BAT in 1991 

Greensand Filtration for Radium Removal 

Greensand filtration technology consists of a conventional filter box with the traditional 

filtration medium replaced by manganese greensand. Manganese greensand has enhanced 

sorptive abilities that allow it to remove certain dissolved ions in addition to normal filtration. 

The water is pre-treated with potassium permanganate to oxidize dissolved materials into more 

insoluble chemical species, which consequently are removed muchmore efficiently by the 

greensand filter. This is a continuous process, except when interrupted for filter backwashing. 

Studies indicate that up to 56% of radium is also removed by greensand filtration. In a pilot 

plant study, the radium removal efficiency was improved to 90% by passing the potassium 

permanganate pre-treated water through a detention tank before filtration. 

Wastes generated by this process include sludge and supernatant from the filter 

backwash. and eventually the greensand media must be disposed of. Radium concentrations in 

the filter backwash have been found to range from ca. 65 to 170 pCiL Dry weight 

concentrations of radium in the greensand medium have been found to vary from ca. 30 to 46 

pCi/g at one plant and from 75 to 250 pCi/g at another (EPA 1994). 

Pre-formed Hvdrous Manganese Oxide (HMO) Filtration 

Although no municipal installations are currently reported in the literature, pilot studies 

have been completed and a full scale demonstration is planned (Clifford 1990a). Pilot studies 

conducted in Illinois consisted of a pre-formed MnOz (HMO) dosage of 2.0 mgL, followed by a 

minimum of ten seconds of mixing and post-mixing diatomaceous earth filtration or multi-media 

filtration to remove the suspended MnOz (which contains the sorbed radium). Greater than 96% 

removals were consistently achieved over the five day run period (Clifford 1990a). Valentine et 

al. (1992) reported average removals of 83%, 79%, and 71% for HMO dosages of 1.O, 0.5, and 

0.2 mg/L (as Mn). Where applicable, costs for HMO treatment were projected to be quite low if 

filtration is already in place (EPA 1994). 

HMO filtration is similar to oxidatiodfiltration in complexity and operator skill 

requirements. Proper dosages must be determined, and if water quality is variable, the dosage 

must be re-calibrated. But, since radium is typically a ground water problem, this is less of a 

concern for this application. Once the proper dose is determined, dosing is relatively easy, 

requires simple equipment, and is fairly inexpensive (NRC 1997). Filters must be backwashed, 
which may require intermediate operator skill. Radium containing wastes include HMO sludge, 

filter backwash, and sludge supernatant. 

CoDreciDitationof Radium with Barium Sulfate 

Addition of a soluble barium s'alt such as barium chloride to water contaminated with 

radium and sulfate will result in the coprecipitation of a highly insoluble radium-containing 

barium sulfate sludge. This process has been primarily used for wastewater treatment. Mine 

wastewater treatment data indicates that up to 95% of radium is removed by this process. A fullscale drinking water treatment plant in South Dakota currently uses this process to treat a radium 

influent level of 16 pCi/L down to < 1 pCiL 

Radium containing wastes generated by ths process include the barium sulfate precipitate 

sludge, filter backwash, and sludge supernatant. 

OtherTechnolopies 

Other technologies exist \vhich demonstrate promise for radionuclides removal from 

drinking water. However. these technologies have not been fully tested in drinking water 

treatment, or have been used onl: in industrial or experimental situations. Examples include 

selective sorbents (e.g.. acn Ilc fikrs or resins impregnated with manganese dioxide) and nonsodium cation exchangers (e g . h! drogen ion and calcium ion exchangers) for radium removal. 

POE IX and RO are not currcntl! Ii~das compliance technologies because of unresolved issues 

regarding waste disposal. post-trcatnicnt disinfection and corrosion control, and costs, but are 

being further considered as smal 1 \tcms compliance technologies. 

Radiation Hazards AssociatrJ Hith 1reatment 

It should be noted that cJutitm I\ required when choosing treatment technologies for 

radionuclides removal. sincc nun! treatments may create radiation hazards through the 

concentration of radionuclide. \\ ithin the treatment unit or in wastestreams. 

Waste Generation and Disno\aI (;uidelines 

# 
Waste Peneration 

In the I99 1 proposed radionuclides rule (EPA 1991a), EPA referenced a 1990 EPA report 

entitled “Suggested Guidelines for the Disposal of Naturally Occurring Radionuclides Generated 

by Drinking Water Treatment Plants” (EPA 1990). In 1992, the Science Advisory Board (SAB) 

reviewed the 1990 guidance and offered several recommendations.’ Among the most important 

SAB recommendations which EPA has acted upon were: (1) the Agency should integrate 

quantitative information on radioactivity in water treatment wastes within the document to 

facilitate decision-making processes: and, (2) the Agency should select and provide rationale for 

its occupational protection approach to water treatment plant workers. 

In response to SAB’s first recommendation, EPA has developed a spreadsheet program 

on floppy disk for computing waste volumes and radioactivity levels for several pertinent water 

treatment processes, along with a user‘s guide. This should aid in the planning and preengineering stages where managers will need information on the types of waste that may be 

generated at new facilities. The spreadsheet program was developed by EPA in August 1993 and 

is entitled “Spreadsheet Program to Ascertain Residuals Radionuclide Concentrations” 

(SPAARC). The program and user’s guide can be obtained by contacting National Technical 

Information Service (NTlS). 5285 Port Royal Rd.. Springfield, VA 22161, (703) 487-4650; and 

ERIC Clearinghouse, 1929 knn) Road, Columbus OH 43210, (614) 292-6717. 

In response to SAB‘s sccond rccommendation. the occupational guidance has been 

revised by the Office of Radiclticm 3nd Indoor Air. It was determined that the doses that 

personnel in water treatmcnt fdcilitic\ uould receive would be substantially lower than the upper 

bounds for workers in radiation t,icilitics. In fact. it appears reasonable to keep treatment plant 

workers’ doses to well \vithin thc ir.\cls recommended for the general public (100 mredyr). 

Consequently. the guidance rectmnic*nds100 mrem/yr as the maximum administrative control 

level in water treatment facilitic\ I tie document also contains more guidance on seeking state 

assistance and/or approval. 

EPA has not yet findired changes to the guidelines based on the SAB recommendation to 

reevaluate the criteria for disposal of’\vastes containing lead-2 10, a byproduct of using activated 

carbon for removal of radon. which is currently unregulated. Since this wastestream does not 

affect disposal options for trcatnicnts concerning the currently regulated radionuclides, it will not 

be discussed further here. 

Other revisions include: (1 ) a new section on mixed (or hazardous) wastes, (2) updates 

reflecting U.S. Nuclear Regulatory Commission (NRC) and other federal regulations, and (3) a 

‘Letter from Dr. R.C. Loehr and Dr. O.F. Nygaard. Science Advisory Board, to W.K. 

Reilly, EPA. September 30, 1992. 
new section on suggested wastestream sampling procedures. 

The report was updated in 1994 with the abovementioned revisions and is entitled 

“Suggested Guidelines for Disposal of Drinking Water Treatment Wastes Containing 

Radioactivity” (EPA 1994). The updated guidelines are summarized in the following two figures 

and table; for details, please refer to the guidelines. Summaries of the guidelines (e.g., EPA 

1996) and relevant background materials (e.g., Reid et al. 1983) may be obtained from EPA or 

the literature. 

The table below summarizes estimated waste volumes, radioactivity levels and types of 

waste generated by several of the above mentioned drinking water treatment processes. These 

estimates are based on standard engineering assumptions and an assumed average daily water 

production of 1.Omillion gallons per day (MGD). 

Characteristics of Selected Water Treatment Wastes (Computed Levels) 

Treatment Waste Characteristics: 

Method Finished Vol. and Radioactivity LConc.

(PCW ~~ ~ ~~ ~ 

Coagulation/ 50/10 U Sludge volume: 10 kgpd 

Filtration t(Uranium) U sludge: 4,000 pCi/g

25112.5 Ra Sludge volume: 22

Softening (Radium) kgpd

Ra sludge: 557 pCi/L 

Ion Exchange Ra waste flow: 97 kgpd 

(Radium) Ra wastes: 207 pCi/L 

50115 U waste flow: 130 kgpd 

Osmosis (U) U wastes: 320 pCiiL 

Types of waste generated 

~ ~ ~ 

Iron or alum sludges from the contact and 

settling basins and from the filter backwash. 

Supernatant from this sludge is a liquid waste. 

Additional liquid waste is generated when the 

sludge is concentrated prior to disposal. 

Settling tank sludge, which is precipitated during 

the softening process. Filter backwash (both 

solids and supernatant) and the sludge 

supernatant are other wastes. 

Liquid waste containing brine, rinse and 

backwash water, and contaminants stripped off 

the resin. In addition, the resin itself is a solid 

waste containing the contaminant exchanged. 

Reject streams which are continuously generated 

during the treatment process. 

I 

Figure 1 is a flowchart summarizing the guidelines for disposal of radioactive liquids. 

The Clean Water Act requires that dischargers of pollutants to navigable waters obtain a National 

Pollutant Discharge Elimination Permit (NPDES), which contains, at a minimum, technologybased effluent limitations. Sufficient flow and channel geometry must be available to prevent a 

buildup of radionuclides in the surface water or sediments to within limits set by the regulator. 

Pretreatment regulations prohibit discharge into sanitary sewers that would cause a municipal 

I 
wastewater treatment plant to violate a NPDES permit. The U.S. Nuclear Regulatory 

Commission (NRC) limits the discharge of wastes containing radioactive materials into sanitary 

sewers. A drinking water treatment plant owner interested in disposing of wastes containing 

radionuclides into an injection well in a Primacy State should consult with the appropriate State 

Agency first. State regulations may be more stringent than the Federal requirements and may 

ban such practice. The plant owner in other States should consult with the appropriate 

Underground Injection Control (UIC) Regional Branch office of the USEPA before deciding to 

dispose of wastes containing radionuclides into an injection well. 

. 
Figure 1. Disposal ofhquid 

wmtes 

WaterTreatment 

LiquidWastes 

pi

Waters 

Ra22840 

u<300 

Injection 

Wells 

Sanitary 

48-­

8'c 
Figure 2 is a flowchart summarizing the guidelines for radioactive solids/sludges. Wastes 

containing less than 3 pCi/g (dry) of radium and less than 50 ug/g (dry) of uranium may be 

disposed of without the need for long-term institutional controls in a municipal landfill if the 

wastes are first dewatered and then spread and mixed with other materials when emplaced. 

Solids/sludges containing 3 to 50 pCi/g (dry) of radium should be disposed of with a physical 

barrier that would protect against radon release and isolate the wastes, and provided with 

institutional controls designed to avoid inappropriate uses of the disposal site. The disposal 

method for solids/sludges containing 50 to 2,000 pCi/g (dry) of radium should be determined on 

a case by case basis. Recovery of the uranium resource may be considered for solids containing 

50 to 500 ug/g (dry) of uranium. Wastes containing more than 2000 pCi/g (dry) of radium or 

more than 500 ug/g (dry) of uranium should be disposed of only as permitted by State 

regulations. 
Figure 2. Disposal of Solid 

Wastes 

(Municipal Physical 

Barrier 

3 C= Ra < 50 v u < 50

7­

1 Water Treatment I 

50 < Ra < 2000 

I Case by I I Case 1 

I I 

r

Ra > 2000 

U > 500 

&State 

I50<U<500 

Recovery 
Section 6.3: Small Systems Compliance Technologies List 

Based on the evaluation of the technologies described in Section 6.2, the following table 

lists the Small Systems Compliance Technologies for radionuclides (EPA 1998b). 

Table 6.1: Technologiesfor Radionuclides 

Unit Technologies Limitations Operator Skill 

(see footnotes) Level Required' 

1. Ion Exchange (IX) ("1 Intermediate 

2. Point of Use (b> Basic 

(POU) IX 

3. Reverse Osmosis (7 Advanced 

(RO) 

4. POUR0 (b> Basic 

5. Lime Softening (d> Advanced 

6. Green Sand ('1 Basic 

Fi1trati on 

7. Co-precipitation (') Intermediate to 

with Barium Sulfate Advanced 

8. Electrodialysis/ Basic to 

Electrodialysis Intermediate 

Reversal 

9. Pre-formed (9 Intermediate 

Hydrous Manganese 

Oxide Filtration 

Raw Water Quality Range 

& Considerations' 

All ground waters 

All ground waters 

Surface waters usually 

require pre-filtration 

May require pre-filtration 

All waters 

Ground waters with suitable 

water quality 

All ground waters 

All ground waters 

' National Research Council (NRC). Sufe Waterfiom Every Tap: Zmproving Water 

Service to Sniull Communities. National Academy Press. Washington, D.C. 1997. 

!. Limitations Footnotes to Table: Technologiesfor Radionuclides: 

The regeneration solution contains high concentrations of the contaminant ions. 

Disposal options should be carefully considered before choosing this technology. 

When POU devices are used for compliance, programs for long-term operation, 

maintenance, and monitoring must be provided by water utility to ensure proper performance 

(see Section 1.4). 
Reject water disposal options should be carefully considered before choosing this 

technology. See other RO limitations described in Chapter 3 and Section 6.2. 

The combination of variable source water quality and the complexity of the chemistry 

involved in lime softening may make this technology too complex for small surface water 

systems. 

e Removal efficiencies can vary depending on water quality. 

This technology may be very limited in application to small systems. Since the process 

requires static mixing, detention basins. and filtration, it is most applicable to systems with 

sufficiently high sulfate levels that already have a suitable filtration treatment train in place 

g This technology is most applicable to small systems that already have filtration in place. 

Chapter 1 indicated that EPA would identify affordable compliance technologies for 

those existing regulations where small system variances or variance technologies are not 

prohibited by the SDWA. There are statutory prohibitions against small system variances for all 

three radionuclides, therefore affordabi lity cannot be considered inhting these technologies. 

The following table contains the compliance technologies the three radionuclides. The statutory 

prohibitions on variance technologies and small system variances are discussed in detail in 

Chapter 1 of this document and Section I\’ of the “Small Systems Compliance Technology Lists 

for Existing National Primary Drinking Water Regulations” (EPA 1998b). 

Table 6.2: Compliance Technologies by System Size Category for Radionuclide 

NPDM’Rs, Affordability is Not Considered 

Compliance Technologies’for System Size Categories 

(Population Served)

I Contaminant I 25-500 1 501 -3,300 I 3,300-10,000 

combined radium-226 

and radium-228 

gross alpha particle 

activity 

total beta particle 

activity and photon 

activity. average znnual 

concentration 

1.2. 2.4. 5.6. 7. 1,2,3,4, 5,6, 

7, 8. 9 

3.4 3,4 3,4 

1.2.3.4 1927 3,4 1,2,3,4 
Section 6.4: Emerging Technologies 

“~ 

, -

I* 

POE ion exchange and POE reverse osmosis have been determined to require further 

evaluation. They have not been listed as compliance technologies since issues regarding ion 

exchange regeneration, other maintenance, waste disposal, post-treatment disinfection, posttreatment corrosion control, etc. remain. EPA will evaluate information regarding these 

technologies in the near future and will include them in future updates, if deemed appropriate. 

References 

Benefield, L.D. and Morgan, J.S. “Chemical Precipitation”. AWWA. Water Oualitv and 

Treatment: A Handbook of Cornmunit!. Water Supplies. 4 ed. Pontius, F.W., ed. McGraw-Hill, 

Inc. New York. 1990. 

Clifford, D.A. “Removal of Radium from Drinking Water”, in Radon. Radium. and Uranium in 

Drinking Water, Cothem and Rebers. eds.. Lewis Publishers, Chelsea, Michigan, 1990. (Clifford 

1990a). 

Clifford, D.A. “Ion Exchange and Inorganic Adsorption”. AWWA. Water Qualitv and 

Treatment: A Handbook of Communir\ \\‘ater SuDDlies. 4ed. Pontius, F.W., ed. McGraw-Hill, 

Inc. New York. 1990. (Clifford Ic)Wb) 

Hess, C.T., Michel. J., Horton. T.R.. hichard. f-I.M., and Coniglio, W.A. “The Occurrence of 

Radioactivity in Public Water Supplii.5 in the United States”. Health Physics. Vol. 48.No. 5. 

pp. 553 - 586. May 1985. 

Lowry, J.D. and Lowry, S.B. ”Rdicmuclides in Drinking Water”. JAWWA. Vol. 80. No. 7. 

pp. 50 - 64. July 1988. 

Michel, Jacqueline. “Relationship 01. Radium and Radon with Geological Formations”. In 

Radon. Radium. and Uranium in 1)rinLinc \\‘ater. Cothem. C.R. and Rebers, P.A., eds. Lewis 

Publishers. Inc. Chelsea. MI. 101) 1 . 

National Research Council (NRC I Snfc \\’ater From Everv Tap: Improving Water Service to 

Small Communities. National Acadcm) Press. Washington, DC. 1997. 

Reid, G.W., Lassovszky. P., and �-latha\vay.S. “Treatment, Waste Management, and Cost for 

Radioactivity in Drinking Water”. L‘SEP.4. Committee Issue Papers. National Workshop on 

Radioactivitv in Drinking Water. hlal 1983. 

Snoeyink?V.L. “Adsorption of Organic Compounds”. AWWA. Water Quality and Treatment: 

A Handbook of Communitv Water SuDdies. 4 ed. Pontius, F.W., ed. McGraw-Hill, Inc. New 

York. 1990. 

c 
Sorg, T.J. “Removal of Uranium from Drinking Water by Conventional Treatment Methods”. 

In Radon. Radium. and Uranium in Drinkinp Water, Cothern and Rebers, eds., Lewis Publishers, 

Chelsea, Michigan, 1990. 

USEPA. “National Workshop on Radioactivity in Drinking Water: Committee Issue Papers”. 

Committee on Treatment, Waste Management, and Cost. Reid, G.W., Chairman. May 1983. 

USEPA. “Suggested Guidelines for the Disposal of Drinking Water Treatment Wastes 

Containing Naturally-Occurring Radionuclides”, Office of Drinking Water. July 1990. 

USEPA. “National Primary Drinking Water Regulations; Radionuclides; Proposed Rule”. 

Federal Register. Vol. 56, No. 138, p. 33050. July 18, 1991. (EPA 1991a). 

USEPA. “Manual of Individual and Non-Public Water Supply Systems”. Office of Water. EPA 

570/9-91-004. May 1991. (EPA 1991b). s 

USEPA. “Technologies and Costs for the Removal of Radionuclides from Potable Water 

Supplies”. Prepared by Malcolm Pirnie, Inc. July 1992. 

USEPA. “Suggested Guidelines for Disposal of Drinking Water Treatment Wastes Containing 

Radioactivity”. OGWDW. Draft, June 1994. 

USEPA. “Technology Transfer Handbook: Management of Water Treatment Plant Residuals” 

Office of Research and Development. EPA/625/R-95/008. April 1996. 

USEPA. “Addendum to: Technologies and Costs for the Removal of Radionuclides from 

Potable Water Supplies - Draft Report”. Prepared by International Consultants, Inc. Draft, June 

1998. (EPA 1998a). 

USEPA. “Announcement of Small Systems Compliance Technology Lists for Existing National 

Primary Drinking Water Regulations and Findings Concerning Variance Technologies”. Federal 

Register. Vol. 63, No. 151, p. 42032. August 6, 1998. (EPA 1998b). 

USEPA. “Cost Evaluation of Small System Compliance Options: Point-of-Use and Point-ofEntry Treatment Units”. Prepared by Cadmus Group, Inc. Office of Ground Water and Drinking 

Water. Draft. September, 1998. (EPA 1998~). 

Valentine, R.L., Kurt, A., Meyer, J., Walsh, D., and Mielke. W. “Radium Removal Using Preformed Hydrous Manganese Dioxides”. Prepared for AWWA Research Foundation (Denver, 

CO). 1992. 

Zapecza, O.S. and Szabo, Z. “Natural Radioactivity in Ground Water - A Review”. National 

Water Summary 1986: Hvdrologic Events and Ground Water Quality. Water-Supply Paper 
2325. p. 50-57. 1986. 
7. SMALL SYSTEMS COMPLIANCE TECHNOLOGIES FOR VOLATILE ORGANIC 

CONTAMINANTS 

Section 7.1: Background 

Volatile organic contaminants (VOCs) are composed of a form of a carbon-based 

molecule. These compounds dissipate or vaporize easily into air at room temperature. Volatile 

organic compounds are usually used as solvents, degreasers, and fumigants. Table 2.1 1 lists the 

National Primary Drinking Water Standards for,regulated VOCs. 

VOCs typically are found in greater amounts in groundwater supplies than surface water 

because exposure to air helps them dissipate from surface supplies. In groundwater supplies, the 

compounds are very mobile and percolate into wells and aquifers. The compounds do not 

degrade readily in the groundwater and, as know or suspected carcinogens, are a potentially 

serious threat to drinking water safety. -_ 

The technologies considered for the small systems compliance list are commonly used in 

the drinking water industry. The BATS for removal of VOCs from drinking water are granular 

activated carbon and packed tower aeration. The technologies listed for treatment of VOCs 

include diffused aeration, multiple tray aeration, spray aeration, and mechanical aeration. The 

other technologies that were considered are listed as emerging technologies due to lack of 

performance data. These technologies include powdered activated carbon, gas permeable 

membrane aeration. advanced oxidation processes, and point-of-entry technologies. 

Point-Of-Use (POUVPoint-Of-Entrv (POE) Technologies 

POU technologies were not be considered for compliance technologies for VOCs because 

POU units are attached only to the tap. Because of the volatile nature of VOCs, the indoor use 

of VOC contaminated water can lead to significant human exposure through non-ingestion routes 

such as inhalation following volatilization (e.g., while showering) or from direct contact with the 

contaminated water. Stakeholders agreed that POU technologies should not be listed for 

treatment of VOCs. 

POE technologies were not considered for compliance technologies for VOCs. The 

potential for off-gas emissions from POE units is more likely to be a problem because these POE 

units would be located near homes. Off-gases may have to be treated using a scnbber, thereby 

increasing the complexity and the cost of the aeration units. Also, there is the potential for water 

quality deterioration from airborne particulates, oxidized inorganics, instability resulting in 

corrosion, and biological growth in the aeration device. Post-treatment disinfection may be 

needed after treatment with POE aeration units. 
Section 7.2: Evaluation of Technologies 

Packed Tower Aeration 

Packed tower aeration has been proven to effectively remove several VOCs from 

drinking water. Packed tower aeration is considered a BAT for VOCs removal. The removal 

efficiency for VOCs is primarily dependant on the air-to-water ratio, packing height, and 

available area for mass transfer. The minimum air-to-water ratio needed to efficiently remove 

VOCs depends upon Henry’s Law Coefficient. , The sizes of packing materials determine the 

available area for mass transfer. Smaller materials may provide greater areas of mass transfer, 

however, an increased pressure drop may occur if the materials are too small. 

Field tests performed in Brewster. NY, Wausau, WI, and Baldwin Park, CA resulted in 

>96% removal efficiencies for VOCs such as tetrachloroethylene, trichloroethylene, cisdichloroethylene, and toluene. The influent concentrations were as great as 600 ugL, using air 

to water ratios of -30: 1 and tower heights ranging from 5.5-7.5 m packed with plastic saddles 

(Ram et al. 1990). 

Some of the concerns with PTA units are that repressurization equipment and blowers 

draw large amounts of electricity. therefore. electrical costs are high. If the unit is not adequately 

ventilated, the contaminant removal efficiency will decrease due to mass transfer constraints. 

These systems may be limited for use in residential areas due to fan noise, and depending on the 

location these systems may be subject to freezing. 

As with most aeration technologies. air quality regulations in certain localities may 

prevent the implementation of these units since large quantities of a contaminant are vented into 

the air. Also, pretreatment for the removal of microorganisms, iron, manganese, and excessive 

particulate matter may be needed. Post-treatment disinfection may have to be used to ensure no 

microbial growth. 

Diffused Aeration 

Similar to PTAs, the efficiency of diffused aerators is dependant upon factors including 

diffuser type, air-to-water ratio. depth of the water in the contact chamber, detention time, and air 

and water temperature. Diffused aeration is considered an accepted technology for treatment of 

VOCs (NRC 1997). 

Several performance studies have been conducted using diffused aerators. Studies 

conducted in Glen Cove, New York (1 984) showed that diffused aerators can efficiently treat 

VOCs with influent concentrations ranging from 50-250 pg/l using air-to-water ratios of 15:1 

(EPA 1985). The removal rates ranged from 50-90+% for 1,2-dichloropropane, cis-l,2­

dichloroethylene, trans- 12-dichloroethylene, toluene, ethylbenzene, chlorobenzene, xylenes, odichlorobenzene, and ethylene dibromide. For the most part, the percent removals were higher 
for VOCs with the higher Henry's Law Coefficients. 

Diffused aeration units may not be as efficient as other aeration methods because it does 

not provide for convective movement of the water thus limiting air-water contact. It is generally 

used to adapt existing plant equipment such as storage tanks or basins. The removal efficiency 

of these systems depends upon the gas to liquid mass transfer rate. The diffused aerator has less 

interfacial area for mass transfer than the PTA; a longer contact time may be needed to achieve 

sufficient removal of the VOCs. On the other hand, increased basin depth, contact basin 

geometry, and turbines to reduce the air bubble size and increase bubble holdup can improve gas 

transfer, thus improving the efficiency of the system. 

With diffused aerators, increased energy costs may be incurred due to post-treatment 

repressurization. .Also, post-treatment disinfection may have to be used to ensure no microbial 

growth. 

Multide Staged Bubble Aerators (MSBA) 

MSBAs are variations to the traditional diffused aerator. These systems are typically 

packaged plant commercial units that are more efficient than the traditional diffused aerator. 

MSBAs further reduce energy costs by optimizing the air to water ratio, contact time, and mass 

transfer area. 

MSBA units are highly efficient. hosever the efficiency depends upon the air-to-waterratio. These units have the same limitations as the diffused aerator. 

Multinle Trav Aeration 

Multiple tray aeration is considered a conventional technology for the removal of VOCs 

from drinking water (NRC 1997). Xlultiplc tray aerators consist of a series of trays with slats, 

perforations, or wire mesh bottoms o\w u hich water falls and eventually collects at the base of 

the unit. The thin film of water forrncd as the \vater flows over the media provides a large 

surface area for mass transfer of the \'OCs tiom water to air. Coke, coal, stone, or ceramic balls 

can be placed in the trays to increase efticiency. 

Multiple tray aeration has been eftcctive in removing 20 to 90 percent of VOCs from 

drinking water (Robeck and Love 1 98;. 1 less et a1 1981). In studies performed in Smyma, 

Delaware reported removal efficiencies ranging from 50 to 90% of trichloroethylene and other 

VOCs. In Camden, New Jersey (1 979) conducted studies to determine the efficiency of the 

aeration unit by testing trichloroethylene. tetrachloroethylene, carbon tetrachloride, and 1,2­

dichlorethane (EPA 1985). Preliminary results indicated that the aerator efficiency could be 

improved by increasing the air-to-water ratio. 

The performance of tray aerators will be impaired in a poorly ventilated building. 

-
Artificial ventilation will be a requirement and may be provided by enclosure and provision of a 

forced draft. The addition of the forced draft may increase the cost of the unit. Post-treatment 

disinfection may be necessary because slime and algae growth can be a problem. Chemicals 

such as copper sulfate or chlorine may have to be used to control the growth. 

Shallow Trav Aeration (STA) 

STAs involve the use of shallow trays, and are more efficient to multiple tray aerators. 

STAs increase the available area of mass transfer; thereby increasing the removal efficiency of 

most VOCs. However, because of the high air-to-water ratio (1 00-900 m3/m3),greater energy 

a costs may be incurred. 

Sprav Aeration 

Spray aeration is an accepted technology where the contaminated water is sprayed 

through nozzles. The small droplets produced expose a large interfacial surface area through 

which VOCs can migrate from the liquid (water) phase to the gaseous (air) phase. Spray aerators 

have been used to effectively treat VOCs (Wood 1982). Case studies (Florida) demonstrated that 

> 99% of VOCs were removed from an influent total VOC concentration between 100-200 pg/l. 

The primary VOCs treated were 1,1-dichloroethane, and trichloroethylene, tetrachloroethylene, 

vinyl chloride, and 1,l ,l -trichloroethane (EPA 1985). 

Although spray aerators are capable of achieving efficient removal of VOCs, this type of 

aerator is for use only when low removal levels of VOCs are needed to reach an MCL. These 

systems may not be as energy efficient as other aeration methods. Also, the spray aerator needs a 

large operational area, which will increase building construction costs and may also increase 

operating problems during cold weather when the temperature is below freezing. 

Mechanical Aeration 

Mechanical aerators are considered accepted technologies for the removal of VOCs from 

drinking water (NRC 1997). Mechanical aerators introduce air into the water by rapidly 

agitating the water surface with a mechanical mixer. They are not as efficient as other aeration 

systems at removing VOCS. The contacting system between the air and water is not as effective 

- for volatilizing the contaminants. These systems often require large basins, long residence times, 

and high energy inputs. However, these systems can be cost-effective because they are adaptable 

to existing basins. and are often installed as a system retrofit. 

Mechanical aerators will probably not achieve VOC removals that are sufficient to attain 

desired water qualities if influent levels are extremely high. Mechanical aerators should be used 

when only low level removals are needed to reach the MCL. 

93 

I 
Granular Activated Carbon 

For the purposes of determining best available technologies (BATs) for removing 

SOCs from drinking water, the Safe Drinking Water Act (0 1412.b.4.D) explicitly states that any 

BAT listed by EPA must be at least as effective as granular activated carbon (GAC). The 

various BATs listed for the Phase I1 and V SOCs are GAC, packed tower aeration (PTA), and, in 

the case of gylphosate, oxidation by chlorination or ozonation (EPA, 1991a, 1991b, and 1992b). 

However, for the purposes of determining the list of compliance technologies for small systems 

of a given size category, the Safe Drinking Water Act (§ 14 12.b.4.E) states that any listed 

technology must be affordable and able to achieve compliance with the maximum contaminant 

level. To emphasize the point, the listed small systems compliance technologies do not have to' 

be as effective as GAC in controlling SOCs. 

Granular activated carbon (GAC) is most often used to treat VOCs in drinking water. 

GAC is listed as a BAT for removal of VOCs. It is packed into columns through which the raw 

water flows. Packing the carbon in columns allows more complete contact between the water 

and activated carbon, greater adsorption efficiency, and greater proce'ss control than is possible 

for powdered activated carbon (Snoeyink 1990). In many cases GAC has been used to treat 

several VOCs to the maximum contaminant levels with influent concentrations ranging up to 500 

pg/l (Ram et al. 1990). 

Although the adsorption characteristics of individual VOCs vary, they are amenable to 

removal by activated carbon adsorption for a period of time or gallons of water treated. The 

amount of water treated depends on the influent contaminant concentration, the amount of carbon 

in the treatment unit, and the time the contaminant is in contact with the carbon. The removal 

efficiency of the carbon system will deteriorate with use, and eventually breakthrough will occur. 

Section 7.3: Small System Compliance Technologies List 

Table 7.1 contains the technologies that have been identified as compliance technologies 

for at least one VOC. The table contains the same structure as other tables with a list of 

limitations that are contained in the footnotes and operator skill level and raw water quality 

issues. 

Table 7.1: Technologiesfor VOCs 

Unit technology Limitations Operator Skill 

(see footnotes) Level Required' Raw Water Quality Range' 

1. Packed Tower (") Intermediate All ground waters 

Aeration (PTA) 

2. Diffused Aeration (" b, Basic All ground waters 
3. Multi-Stage 

Bubble Aerators 

4.Tray Aeration 

5. Shallow Tray 

Aeration 

6. Spray Aeration 

7. Mechanical 

Aeration 

8. Granular Activated 

Carbon (GAC) 

v,c) Basic All ground waters 

(a.d) Basic All ground waters 

("3') Basic All ground waters 

("7') Basic All ground waters 

v*g) Basic All ground waters 

(h) Basic All ground waters 

Limitations Footnotes to the Technology Tables for VOCs 

a Pretreatment for the removal of microorganisms, iron, manganese, and excessive 

particulate matter may be needed. Post-treatment disinfection may have to be used. 

May not be as efficient as other aeration methods because it does not provide for 

convective movement of the water thus limiting air-water contact. It is generally used only to 

adapt existing plant equipment. 

This units are highly efficient, however the efficiency depends upon the air-to-water 

ratio. 

Costs may increase if a forced draft is used. Slime and algae growth can be a problem, 

but can be controlled with chemicals such a copper sulfate or chlorine. 

e These units require high aidwater ratios (100-900 m3/m3) 

For use only when a low removal levels are needed to reach an MCL because these 

systems may not be as energy efficient as other aeration methods because of the contacting 

system. 

g For use only when a low removal levels are needed to reach an MCL because these 

systems may not be as energy efficient as other aeration methods because of the contacting 

system. The units often require large basins, long residence times, and high energy inputs which 

may increase costs. 

See the SOCs compliance technology table for limitation regarding these technologies. 

Chapter 1 indicated that EPA would identify affordable compliance technologies for 

those existing regulations where small system variances or variance technologies are not 

prohibited by the SDWA. There are statutory prohibitions against small system variances or 
variance technologies for 2 of the 2 I VOCs. Table 7.2 contains the compliance technologies for 

the 19 VOCs where affordability was considered. Affordability only plays a role in removing 

options in the smallest size category. The technology costs are based on treatment of all of the 

water. The technologies that did not meet the affordability criteria in the smallest size category 

are also identified in the next column called “other compliance technologies.” These 

technologies may be affordable if the concentration of the contaminant is low enough that a 

portion of the influent stream can be treated and blended with an untreated portion to still meet 

the MCL. This blending would reduce both the capital .and operating and maintenance costs of 

the process. Systems and States should consider these options under those circumstances. Table 

7.3 contains the compliance technologies for the remaining two VOCs where affordability was 

not considered due to statutory prohibitions (EPA 1998). 

Table 7.2: Compliance Technologies by System Size Category for those VOC NPDWRs 

where Affordability is Considered 

Volatile Organic 

Contaminant 

I Benzene 

Carbon 

cis-1.2-

Dichloroethylene 

I1,2-

Dichloroethane 

1,lDichloroethylene 

Dichloromethane 

~ 

1,2-

Dichloropropane 

Ethylbenzene 
8 

8 

Tetrachloroethylene I 1,2,3,4,5 8 

~~ 

trans- 1,2- 8 P 

Dichloroethylene 

1, 2,4- 8 

Trichlorobenzene 

1, 1, 1- 1,2,3,4, 5.6 8 

Trichloroethane 

1, 1,2- 8 

Trichloroethane 

8 

Xylenes (total) I 1.2.3.4. 5 8 

1,2,3,4,5, 8 1,2,3,4. 5, 8 

1,2,3,4,5, 8 

1,2,3,4, 5, 8 

1,2.3,4, 5, 8 

1,2,3,4,5, 8 

1,2, 3,4,5, 8 1 1,2,3,47 5,8 

1,2,3,4.5, 8 

Table 7.3: ComplianceTechnologics by System Size Category for those VOC NPDWRs 

where Affordability is Not Considered 

Compliance Technologies for System Size Categories 

Volatile Organic (Population Served) 

Contaminant

I 25 - so0 501 - 3,300 3,301 - 10,000 

I Styrene I 1. 2. 3. 4. 5. 8 1 1.2. 3.4, 5, 8 I 1,2. 3,4,5, 8 

Vinyl Chloride 1.2. 3.4. 5. 8 1,2, 3.4, 5, 8 1,2. 3,4, 5, 8 

Section 7.4: Emerging Technologies 

Powdered Activated Carbon 

PAC is generally less than 50 pm in diameter and is added to the raw water line or to a 

mixing basin. In order to treat VOCs effectively, PAC must contact all of the incoming water. 

Following adsorption, the carbon containing the organic compounds is settled or filter from the 
-- 

water and disposed of with the plant sludge. In some cases no modifications other than the 

addition of PAC dosing equipment need to be made to an existing plant because the normal 

contact time used for other elements of water treatment is sufficient for contaminant adsorption 

onto PAC. However, the contact time has to be determined prior to the design of the process. 

The dose of PAC added to the system has to be adapted to deal with varying source water 

quality. 

The removal efficiencies of VOCs depend upon sufficient contact time, proper mixing, 

effects of chlorine and other chemicals, and the removal method of spent PAC. However, PAC 

requires coagulatiodsedimentation facilities such as feed equipment, mixing chambers, clarifiers, 

and filtration. If these facilities are in place, PAC is simple to employ on a small scale. PAC is 

considered an emerging technology because long-term performance for treatment of VOCs has 

not been evaluated. 

Gas-Permeable Membrane Aeration 

Gas-permeable membrane aeration is an emerging technology (NRC 1997). In gas 

permeable membrane systems, water flows through the interior of hollow membrane tubes 

constructed of a material that allows gases but not liquids to pass through. The large surface area 

for air-water contact allows for removal of VOCs (Semmens et al. 1989). Some studies have 

shown that when compared with other aeration systems, gas-permeable membrane systems offer 

the highest removal efficiencies of all contacting devices (NRC 1997). However, this technology 

has to be considered emerging because long-term performance has not been evaluated. 

Advanced Oxidation Processes 

Advanced oxidation is considered an emerging technology. The majority of advanced 

oxidation research as focused on treatment of chlorinated organics present in groundwater. 

Advanced oxidation processes can oxidize some volatile organic compounds such as 

trichloroethylene and tetrachloroethylene to completion. An added benefit is that advanced 

oxidation processes may used for disinfection. However, AOPs have only been used in one 

drinking water system on the pilot level. Therefore, this technology is considered emerging 

because long-term performance has not been evaluated. 

References 

Hess, A.F., Dysken, J.E., and Cline, G.C. “Case Studies Involving Removal of Organic 

Chemical Compounds from Groundwater”. Presented at the Preconference Seminar Concerning 

Organic Chemical Contaminants in Ground Water at the 1981 Annual Conference of the 

American Water Works Association. St. Louis, Missouri. June 7-1 1, 1981. 

National Research Council (NRC). Safe Water From Every Tap: ImDroving Water Service to 

Small Communities. Committee on Small Water Supply. National Academy Press, Washington, 
DC. 1997. 

c 

Ram, N.M., Christman, R.F., Cantor, K.P. ,Significance and Treatment of Volatile Organic 

ComDounds in Water Supdies. Lewis Publishers. pp. 363-391. 1990. 

Robeck, G.G. and Love, O.T. “Removal of Volatile Organic Contaminants from 

Ground Water”. Presented at the International Conference on Ground Water Contamination 

from Organo-Chlorine Compounds of Industrial Origin. Milano, Italy. January 1983. 

Semens, M.J., Qin, R., and Zander, A.K. “Using Microporous Hollow-Fiber Membranes to 

Separate VOCs from Water”. Journal of the American Water Works Association. 8 l(4):162-167. 

1989. 

Snoeyink, V. L. “Adsorption of organic compounds”. Chapter 13 in Water Quality and 

Treatment: A Handbook of Community Water Supplies, Fourth Edition. Denver: American 

Water Works Association. 1990. 

USEPA. “Technologies and Costs for the Removal of Volatile Organic Chemicals from Potable 

Water Supplies.” Prepared by Environmental Science and Engineering. May 1985. 

USEPA. “National Primary Drinking Water Regulations; Final Rule.” Federal Register. Vol. 

6 56, No. 20, p. 3526. January 30. 1991. (EPA 1991a) 

USEPA. “National Primary Drinking Water Regulations: Final Rule”. Federal Register. Vol. 

56, NO. 126, p. 30266. July 1, 1991. (EPA 1991b) 

USEPA. “National Primary Drinking Water Regulations: Synthetic Organic Chemicals and 

Inorganic Chemicals; Final Rule”. Federal Register. Vol. 57, No. 138, p. 3 1776. July 17, 1992. 

USEPA. “Variance Technology Findings for Contaminants Regulated Before 1996”. EPA 815-

R-98-003. Office of Water. September 1998. 

Wood. P. R. Removal of Volatile Organic ComDounds from Water bv Sprav Aeration. Paper 

presented at Seminar of Small Water Systems Technology. US Environmental Protection 

Agency. Cincinnati, Ohio. April 1982. 
8. SMALL SYSTEMS COMPLIANCE TECHNOLOGIES FOR OTHER SYNTHETIC 

ORGANIC CONTAMINANTS 

Section 8.1: Background 

The Phase I1 and V SOCs are a diverse group of chemicals in terms of properties, 

although most of them are used as pesticides and find their way into drinking water through this 

common use. They vary widely with regard to chemical structure, make-up, and charge, which 

causes them to exhibit a range of environmental behaviors. For the same reasons, the removal of 

these compounds in drinking water treatment processes also varies. For example, Miltner et al. 

(1989) demonstrated that water softening removed a significant percentage of carbofuran, but for 

the other seven pesticides studied, softening was not effective. Miltner et al. (1989) also 

demonstrated that clarification. filtration, and chlorination were not effective for any of the eight 

pesticides studied. In general. less conventional treatment like activated carbon, membranes, air 

stripping, ozonation, or advanced oxidation is required (Clark et a1.;- 1990). 

The physical and chemical properties (Schwarzenbach et al. 1993, Kamrin 1997) that 

determine the behavior of SOCs in the environment and during treatment processes include 

volatility (tendency to evaporate), water solubility, and resistance to chemical degradation. 

Volatile SOCs can enter the atmosphere and. if chemically persistent, travel great distances 

before being deposited. Modes of atmospheric deposition of pollutants include dry-fall, or 

deposition of the pollutant directly from the air or when attached to settling dust, etc. and wetfall, or deposition of the pollutant through rainfall, snow, or other precipitation (Schnoor 1996). 

Through atmospheric deposition. contaminants can reach surface waters and soils that are 

otherwise pristine. For examplc. uatcrs and soils that do not receive agricultural run-off can 

become contaminated with pcsticidcs bccause of atmospheric deposition. Water solubility is 

another very important propcny that affects the environmental mobility and treatability of SOCs. 

If an SOC is very water soluhlc. it can be readily transported in run-off (Larson et al. 1997), 

through ground water (Barbash and Kesek 1996), and is more difficult to remove with granular 

activated carbon (GAC) (Snoe>.inh1990. p. 786). If the SOC is relatively insoluble, it tends to 

sorb to the soil matrix in the casc of ground water. In the case of surface water, insoluble SOCs 

may sorb to suspended particles. some of which will settle out, or directly to the sediment matrix. 

In general, the less soluble an SOC. the greater its tendency to sorb to GAC (Snoeyink 1990, 

Schwarzenbach et al. 1993). 

Ten technologies for the removal of the Phase I1 and Phase V synthetic organic chemicals 

(SOCs) have been evaluated as potential compliance technologies for small systems: GAC, 

PAC, aeration, oxidation. advanced oxidation, ultrafiltration, nanofiltration, and reverse osmosis. 

For the purposes of determining best available technologies (BATs) for removing SOCs from 

drinking water, the Safe Drinking Water Act (5 14 12.b.4.D) explicitly states that any BAT listed 

by EPA must be at least as effective as granular activated carbon (GAC). The various BATs 

listed for the Phase I1 and V SOCs are GAC, packed tower aeration (PTA), and, in the case of 

gylphosate. oxidation by chlorination or ozonation (EPA 1991a, 1991b and 1992a). However, 

.1 
for the purposes of determining the list of compliance technologies for small systems of a given 

size category, the Safe Drinking Water Act ( (51412.b.4.E) states that any listed technology must 

be affordable and able to achieve compliance with the maximum contaminant level. To 

emphasize the point, the listed small systems compliance technologies do not have to be as 

effective as GAC in controlling SOCs. 

Section 8.2: Evaluation of Technologies 

Granular activated carbon (GAC) and powdered activated carbon (PAC) 

The activated carbon processes are described in Chapter 3 of this document and in detail 

in terms of SOCs removal in the "technologies and costs" regulatory support documents for the 

Phase I1 and Phase V final rules (USEPA 1990 and 1992b). Based on past research and pilot 

scale work, GAC is considered to be the best available broad spectrum removal process for 

SOCs. PAC, when applied properly, works well for many of the SQCs. However, both 

technologies exhibit a wide rangc of removal efficiencies, depending upon site specific 

conditions and the identify of the SOC in question. Site specific conditions that may affect 

percent removal include the prescnce of other "competing" contaminants, including natural 

organic matter, biofilm de\pclopment on the carbon surface. temperature, pH, variable influent 

concentrations (leading to dcsorptron ). activated carbon particle size and specific surface area, 

and hydraulic loading rate (,-lll%'.-l - ASCE 1998). Due to the potential for variability in 

removal efficiencies. some degree of source water-specific testing is needed to ensure adequate 

removal. In cases in Lvhich the ran uater has a low concentration of natural organic matter, such 

as most ground waters. ine\pcn\i\c knch-scale tests may be adequate to predict performance 

(NRC 1997). For surface \\atcr \!\~crns. pilot tests may be required. 

Discussions of rnodcl, pri*Jict full-scale performance that also discuss basic activated 

carbon principles in the contc.\r (It JrinAing water regulations are found in numerous sources 

(e.g., Sontheimer 1988. Smw! irih 1 UW. Speth 1990. Speth and Adams 1993). Design 

parameters are discussed in a IXILT? 01. text books (e.g., AWWA - ASCE 1998),journal articles 

(e.g.. AWWA 1989). and El'.\ rLyuI3tury support documents (USEPA 1990 and 1992b). 

POE and POU GAC art' h11h potentially useful for small systems applications. However, 

issues regarding cost-effecti\ cnc.\ 3nd backwash waste disposal for POE GAC preclude its 

being listed this year. POE (;:IC' \\ ill continue to be evaluated as an emerging technology. POU 

GAC is currently commonl! used to remove taste and odor compounds and other organic 

contaminants in a non-regulatory manner and is a potentially cost-effective way for small 

systems to remove regulated SOCs. Regulator\.,issues regarding POU use were described in 

Chapters 1 and 3. The performance and GAC bed life depend on the amount of GAC used in the 

device, the contact time, and the nature of the contaminants being removed. A proper monitoring 

and unit replacement schedule must be maintained to ensure that good removals are maintained 

(NRC 1997). 
Packed Tower Aeration (PTA) 

Packed tower aeration (PTA) is BAT for several of the more volatile Phase I1 and Phase 

V SOCs, namely dibromochloropropane, ethylene dibromide, di(2-ethylhexyl) adipate, and 

hexachlorocyclopentadiene. The PTA process is described in Chapter 3. The issues and caveats 

that apply to PTA treatment for VOCs removal, as described in chapter 7. 

Other Aeration Technoloyies 

Chapters 3 and 7 describe other aeration technologies relevant to the removal of the 

volatile Phase I1 and V SOCs. 

Oxidation 

Oxidation by chlorination or ozonation is BAT for glyphosate. Other oxidation processes 

are potentially applicable, but sufficient published data is not available. Issues and caveats 

regarding chlorination and ozonation use by small drinking water systems are described 

elsewhere (EPA 1997, EPA 1998b). 

Section 8.3: Small Systems Compliance Technologies List 

Based on the evaluation of the technologies described in Section 8.2, the following table 

lists the Small Systems Compliance Technologies for at least one Phase I1 or V SOC (EPA 

1998a). The table contains the same structure as other tables with a list of limitations that are 

contained in the footnotes and operator skill level and raw water quality issues. 

~ ~~ ~~ I ~~ 

Table 8.1: Technologies for SOCs ~~ 

Unit Technology Limitations Operator Skill Level Raw Water Quality Range 

(see footnotes) Required' and Considerations' 

1. Granular Basic Surface water may require 

Activated Carbon pre-filtration 

(GAC) 

~ 

2. Point of Use Basic Surface water may require 

(POU) GAC pre-filtration 

3. Powdered Intermediate All waters 

Activated Carbon f 

4. Chlorination 1 - ~ 

Basic Better with high quality 

water 
5. Ozonation 

6. Packed Tower 

Aeration (PTA) 

7. Diffused 

Aeration 

8. Multi-Stage 

Bubble Aerators 

9. Tray Aeration 

10. Shallow Tray 

Aeration 

' 

Basic Better with high quality 

waters 

Intermediate All ground waters 

Basic All ground waters 

Basic All ground waters 

Basic All ground waters 

Basic All ground waters 

National Research Council (NRC). Safe Waterporn Every Tap: Improving Water 

Service to Small Communities. National Academy Press. Washington, DC. 1997. 

Limitations footnotes for Table 10: Technologies for SOCs 

a When POU devices are used for compliance, programs for long-term operation, 

maintenance, and monitoring must be provided by water utility to ensure proper performance. 

Most applicable to small systems that already have a process train including basins 

mixing, precipitation or sedimentation, and filtration. Site specific design should be based on 

studies conducted on the system's particular water. 

See the SWTR compliance technology tables for limitations associated with this 

technology. 

Pretreatment for the removal of microorganisms, iron, manganese, and excessive 

particulate matter may be needed. Post-treatment disinfection may halie to be used. 

e May not be as efficient as other aeration methods because it does not provide for 

convective movement of the water thus limiting air-water contact. It is generally used only to 

adapt existing plant equipment. 

This units are highly efficient, however the efficiency depends upon the air-to-water 

ratio. 

Costs may increase if a forced draft is used. 

Chapter 1 indicated that EPA would identify affordable compliance technologies for 

those existing regulations where small system variances or variance technologies are not 

prohibited by the SDWA. There are statutory prohibitions against small system variances or 

variance technologies for 14 of the 32 SOCs. The following table contains the compliance 

technologies for the 18 SOCs where affordability was considered. Affordability only plays a role 

in removing options in the smallest size category. The technology costs are based on treatment 

'. 

I 
of all of the water. The technologies that did not meet the affordability criteria in the smallest 

size category are also identified in the next column called “other compliance technologies.” 

These technologies may be affordable if the concentration of the contaminant is low enough that 

a portion of the influent stream can be treated and blended with an untreated portion to still meet 

the MCL. This blending would reduce both the capital and operating and maintenance costs of 

the process. Systems and States should consider these options under those circumstances. The 

subsequent table contains the compliance technologies for the remaining fourteen SOCs where 

affordability was not considered due to statutory prohibitions. The statutory prohibitions on 

variance technologies and small system variances are discussed in detail in the Variance 

Technologies Findings Document (EPA 1998c). 

Table 8.2: Compliance Technologies by System Size Category for those SOC NPDWRs 

Con aminant 

Alachlor 

Atrazine 

Carbofuran 

Dibromochloropropane 

2,4-D 

Lindane ~ ~ 

Methoxychlor 

Pentachlorophenol 

Dalapon 

Di(2-ethylhexy l) 

adipate 

’ 

where Affordability is Considered 

ComplianceTechnologies for System Size Categories 

(Population Served) ~ ­

25 - 500 25 - 500 501 - 3,300 3,301 - 10,000 

(afford) ~ 1 (other) I-(afford) (afford) 

2. 3 I 1 1,273 1,2,3 -

2, 3. 6. 7. 8. 1 

9.10 8, 9, 10 

2. 3 1 1,2,3 

2. 3-- I 1 I 1,2,3 I 1.2.3 ~ ~ 

2. 3 1 1,2,3 1,2,3 

2, 3 1 1,2,3 1.2, 3 

2. 3. 6. 7. 8, 1 1,2,3,6,7, 1,2,3,6,7,8,9,10 

9. 10 8,9, 10 

This affordability determination assumes that the small system already has the 

appropriate treatment train in place for mixing, contact. and filtration. 
Contaminant 

Contaminant 

Chlordane 

Ethylene Dibromide 

Compliance Technologies for System Size Categories 

(Population Served) 

Compliance Technologies for System Size Categories 

(Population Served) 

25 - 500 501 - 3,300 3,300 - 10,000 

1,2, 3 1, 233 1,2,3 

1,2, 3, 6, 7, 8, 9, 1, 2, 3, 6, 7, 8, 9, 1, 2, 3,6, 7, 8, 9, 

10 10 10 

Heptachlor I 1.2,3 I 1, 2, 3 I 1,2,3 

Heptachlor Epoxide I 1, 2, 3 I 1,2, 3 1, 2,3 
Table 8.3: Compliance Technologies by System Size Category for those 

SOC NPDWRs where Affordability is Not Considered 

Contaminant 

Polychlorinated 

Biphenyls 

Toxaphene 

2,4,5-TP 

Benzo(a)pyrene

11 Endrin 

Compliance Technologies for System Size Categories 

(Population Served) 

25 - 500 

17273 

172, 3 

1,2,3 

1.2,3 

1 1.293 

I ~~ 

Section 8.4: Emerging Technolctgies 

Membrane Processes 

Hexachlorobenzene 

Oxamyl 

2,3.7,8-TCDD 

(Dioxin) 

)I Acrylamide 

11 Epichlorohydrin 

1.2,3 

1.2,3 

1.2.3 

S ..I (treatment 

icchnique) 

501 - 3,300 3,300 - 10,000 

1,273 

1,273 

1,293 

1,273 

1,2,3 

N/A (treatment N/A (treatment 

technique) technique) 

N/A N/A 

Reverse osmosis. including POE and POU RO. and nanofiltration show promise as 

compliance technologies fur SOCs. 1lowever, efficient rejection of a SOC depends upon the 

specific membrane (surface charge. pore size and distribution. etc.), the source water quality, and 

the environmental conditions of the test (AWWA - ASCE 1998). Very importantly, rejection of 

SOCs must be confirmed through bench or pilot-scale testing. Because data on SOCs removal via 

membranes are limited and because there are so many variables that affect membrane removal 

efficiencies for SOCs, EPA will evaluate them further before listing any membrane technologies 

as small systems compliance technologies. 
POE GAC 

As described above, POE GAC shows promise and will continue to be evaluated as a 

potential small systems compliance technology. 

References 

AWWA. Organics - Removal bv Granular Activated Carbon. American Water Works Association.

Denver, CO. 1989. 

AWWA - ASCE. Water Treatment Plant Design. 31d ed. American Water Works Association and 

the American Society of Civil Engineers. McGraw-Hill, Inc. New York. 1998. 

Barbash, J.E. and Resek. E.A. Pesticides in Ground Water: Distribution. Trends. and Governing, 

Factors. Vol. I1 of the Series. Pesticides in the Hvdrologic System.--USGS. Ann Arbor Press, 

Inc. 1996. 

Conlon, W. J. Membrane Proccsscs. AWWA, Water Oualitv and Treatment: A Handbook of 

Communitv Water Suudies. 41hed.. Pontius, F., ed. McGraw-Hill, Inc. New York. 1990. 

Jacangelo. J.G. The Developmcnt of'Llembrane Technology. International Report (IR 3) Water 

Supulv: Review Journal of thc 1ntcm;itional Water SuDply Association. Vol. 9, Numbers 3/4. 

1991. 

Kamrin. M.A. 1

Lewis Publishers. 

New York. 1997. 

Larson. S.J.. Capel. P.D.. and \~.IILW Ai. M.S. Pesticides in Surface Waters: Distribution, 

Trends. and Governing Factcrr\ 1 01 111 of the Series, Pesticides in the Hvdrologic System. 

USGS. Ann Arbor Press. Inc 1 (w' 

National Research Council >;it? \\ ,itc'r From Every Tap: Improving Water Service to Small 

Communities. National Acctdcrn! Prcss. Washington, D.C. 1997. 

Schnoor. J.L. Environmental 12lodclinc: Fate and Transport of Pollutants in Water. Air. and Soil. 

John Wiley & Sons, Inc. New l'ork. p. 547. 1996. 

Schwarzenbach. R. P., Gschwend. P.. and Imboden, D. Environmental Organic Chemistrv. J. 

Wiley & Sons, Inc. New York. 1993. 

Sontheimer, H., Crittendon. J. C., and Summers, R. S. Activated Carbon for Water Treatment. 

DVGW-Forschungsstelle, 2"d ed. Karlsruhe, FRG. 1988. 
-- 

Snoeyink, V. L. “Adsorption of Organic Compounds”. AWWA, Water Oualitv and Treatment: 

A Handbook of Communitv Water Supplies. 4‘hed.. Pontius, F., ed. McGraw-Hill, Inc. New 

York. 1990, 

Speth, T. F. “Removal of VOCs from Drinking Water by Adsorption”. Significance and 

Treatment of Volatile Organic ComDounds in Water Supplies. N. Ram, K. Cantor, and R. 

Christman, eds. Lewis Publishers, Inc. Ann Arbor, MI. 1990. 

Speth, T. F. and Adams, J. Q. “GAC and Air Stripping Design Support for the Safe Drinking 

Water Act”. Stratepies and Technolopies for Meeting SDWA Reauirements. R. Clark and R. 

Christman, eds. Lewis Publishers, Inc. Ann Arbor, MI. 1993. 

USEPA. “Technologies and Costs for the Removal of Synthetic Organic Chemicals from Potable 

Water Supplies”. Office of Drinking Water. September, 1990. 

USEPA. “National Primary Drinking Water Regulations; Final Rule.” Federal Repister. Vol. 

565, No. 20, p, 3526. January 30, 1991. (EPA 1991a) 

USEPA. “National Primary Drinking Water Regulations; Final Rule”. Federal Register. Vol. 56, 

No. 126, p. 30266. July 1 1991. (EPA 1991b) 

USEPA. “National Primary Drinking Water Regulations; Synthetic Organic Chemicals and 

Inorganic Chemicals; Final Rule”. Federal Repister. Vol. 57, No. 138, p. 3 1776. July 17, 1992. 

(EPA 1992a) 

USEPA. “Technologies and Costs for the Removal of Phase V Synthetic Organic Chemicals 

from Potable Water Supplies”. Prepared by MalcoIm Pirnie, Inc.. January, 1992. (EPA 1992b) 

USEPA. “Small System Compliance Technology List for the Surface Water Treatment Rule”. 

EPA 8 15-R-97-002. Office of Water. August, 1997. 

USEPA. “Announcement of Small Systems Compliance Technology Lists for Existing National 

Primary Drinking Water Regulations and Findings Concerning Variance Technologies”. Federal 

Rerrister. Vol. 63. No. 151, p. 42032. August 6, 1998. (EPA 1998a). 

USEPA. “Small Systems Compliance Technology List for the Surface Water Treatment Rule 

and the Total Coliform Rule”. EPA 815-R-98-001. September, 1998. (EPA 1998b). 

USEPA. “Variance Technology Findings for Contaminants Regulated before 1996”. EPA 8 15-

R-98-003. Washington, D.C.: EPA Office of Water. September 1998. (EPA 1998~). 

Weber, W. J., Jr. Phvsicochemical Processes for Water Ouality Control. Wiley - Interscience. 

New York. 1972. 

I 
Wiesner, M. R.. Hackney, J., Sethi, S.. Jacaneglo, G., and Laine, J. M. “Cost Estimates for 

Membrane Filtration and Conventional Treatment”. Journal of the American Water Works 

Association. 86(12). pp. 33 - 41. 1994. 

h 
APPENDIX A 

RELEVANT PARTS OF SECTIONS 1412 OF THE REVISED (1996) SDWA 
SEC. 105. TREATMENT TECHNOLOGIES FOR SMALL SYSTEMS. 

Section 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; 

“(11) a population of 3,300 or 

fewer but more than 500; and 

“(111) 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 pointof-entry or point-of-use treatment units. Pointof-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 

[[Page 1 10 STAT. 162611 

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 

compliance.--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, ;he 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). (I1j, and (111) 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 ma!. at any time after a national 

primary drinking \rater regulation has been 

promulgated. supplement the list of technologies 

describing addititd or new or innovative 

treatment technolog ICS that meet the requirements 

of this paragraph tor categories of small public 

water system3 Jc-kirikcf in subclauses (I), (11). 

and (111) of clauw I 11 that are subject to the 

regulation. 

"(v) <<SOTI Kccords.>> Technologies that 

meet surface N .iter rreatment rule.--Within one 

year after thedate ot' enactment of this clause. 

the Administrator 311311 list technologies that 

meet the Surface N'atcr Treatment Rule for each 

category of public ivater systems described in 

subclauses (1). (11). and (111) of clause (ii).". 

n