'2: 

# (laUnited States Environmantal Protection Office of Water EPA 81 5-R-98-002 Agency 4607 September 1998 

# \f/EPA 

# Small System ComplianceTechnology Listfor 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 ofFigures 1. Introduction Section 1.1 : SafeDrinking Water Act Implementation Section 1.2: Need for 

### a Small System Technology Requirement Section 1.3: Small System Treatment Technology Requirements ofthe 1996SDWA Section 1.4: Point-of-Entry and Point-of-Use Treatment Units as Compliance Technologies Section 1.5: Format and Content 

### ofthis Small System Compliance Technology List Section 1.6: Stakeholder Involvement Section 1.7: Organization ofthe 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) TrihalomethanesNIPDWRs (44

## FR 68624) Fluoride Rule 

### (51

## FR 1 1396) Phase 

### I Rule (52

## FR 25690) Phase 

### I1 Rule (56

## FR 3526) and Phase IIb Rule (56

## FR 30266) Lead and Copper Rule (56

## FR 26460) Phase V Rule (57

## FR 31776) Summary ofNational Primary Drinking Water Regulations 18 

### 3. Descriptions of Technologies 22 4. Affordable Technology Determinations 42 Section 4.1 National-Level Affordability Criteria 42 Section4.2 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

### -- 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 

### ofTechnologies Section 6.3: Small SystemsCompliance Technologies List Section 6.4: Emerging Technologies 7. Small Systems Compliance Technologies for Volatile Organic Contaminants Section 7.1 : Background Section 

### 7.2: Evaluation ofTechnologies Section 7.3: Small Systems ComplianceTechnologies List Section 7.4: Emerging Technologies 8. Small SystemsCompliance 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 ComplianceTechnologies Figure 

### 3. Compliance Technologies 

### (NoAffordability) Chapter 

### 6 Figure 1. Disposal ofLiquid 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.
Dueto the 1996 SDWA’s emphasisonpublic information and participation, 

### as well as EPA’s desire to seek a broad range 

### ofpublic input,the stakeholder process that was begun during the 1995 drinking water program redirection effort has been greatly expanded. Toprovide focus, EPA

### has grouped many ofthe statutory deadlines into more general project areas. Each ofthese 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. 

### Thisproject area is a part ofone ofthe primary objectives of the 1996 SDWA, which is to more fully consider the needs of small drinking water systems in developing and implementing drinlungwater regulations. Themission ofthe Treatment Technology Team is to identify andordevelophigh quality, cost-effective treatment technologies to meet regulation development and program implementation objectivesand deadlines. Theteam’s short-termgoals aretoprepare: (

### I ) by August 

### 6, 1997.the list oftechnologies that small systemscan use to comply with the Surface M’ater Treatment Rule (SWTR); 

### (2) by August 

### 6, 1998,the list of technologies that small systemscan use to comply with all ofthe 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 futureregulations; (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 ofthese short-term goals in August, 1997. A Federal Register notice dated August 11, 1997published the compliance technology list for the surface water treatment rule (EPA 1997a). Thenotice also announced the availability of a guidance manual entitled ”Compliance Technology List forthe Surface WaterTreatment Rule” (EPA 1997b)’ which provided more detailed background information supporting the list oftechnologies 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 tothe guidance manual that supported the original 

### SWTR list of compliancetechnologies. The updated guidance manual isentitled “Compliance Technology List forthe Surface WaterTreatment Rule andthe Total 

# 5Coliform 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. Thelist ofcompliance technologies for the total coliform rule isone ofthe listsrequired by Section 1412(b)(4)(E)(iii) ofthe SDWA.
The Environmental Protection Agency met both the second and hrdofthe 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 concerningvariance technologies forthe contaminants regulated before 1996. EPA did not list any variance technologies for contaminantsregulated before 1996in this notice. This guidance manual was developed to provide more detail onthe list of compliance technologies for the nonmicrobial contaminantsregulated before 1996. A guidancemanual entitled “Variance Technology Findingsfor ContaminantsRegulated before 1996”hasbeenprepared todescribetheproceduresthat were used to make the determination that there would be no variance.technologies for contaminants regulated before 1996at this time (EPA 1998~).
Section 1.2: Need for a 

### Small System TechnologyRequirement
The 1986SDWAidentified a process for setting maximum contaminantlevels (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 

### ofthe 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 ofthe 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)ofthe 1986 SDWA listed the conditions under which a treatment technique could be promulgated in lieu of an MCL. When these conditionsare met, the Act statesthat 

### “.

.. the Administrator must identifythose treatment techniques which, in the Administrator’sjudgement, 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 fortreatment techniques like the Lead and CopperRule.
There is one other treatment technique rule in the group of non-microbial contaminants regulated before 1996:epichlorohydrin and acrylamide areregulated 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 SWTRortheLead and CopperRule,the treatment techniques forthese 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 

### -

. LIthose public water systems using acrylamide or epichlorohydrin in a treatment process to provide written certification annually to the Statethat the combination ofdose 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 commonpopulation sizecategoriesused were 

### 50,000

## - 75,000people and 

### 100,000

### - 500,000people. Thetechcaldemands andcostsassociated with technologies that are feasible based onregional and large metropolitan water systems often make these technologies inappropriate for small systems. The 1996Amendments 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 TreatmentTechnologyRequirements 

### ofthe 

### 1996 SDWA
Sincelarge systemswere used 

### asthebasis forthe feasibility determinations, someofthe existing BATSfor MCLs and the existingtreatment techniques may not be appropriate for small systems. In responseto this concern, the 1996SDWA specifically requires EPA tomake technology assessments, relevant to thethree categories of small systemsrespectively forboth existing and futureregulations, in additionto the pre-1996 Amendments BATprotocol. Thethree population-served size categories of small systems defined by the 1996SDWA 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 toboth 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 compliancetechnologies 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 

### ofa 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 achievethe maximum reduction or inactivation efficiency that 

### is affordable considering the size ofthe system and the quality ofthe 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 1996Amendments have given the variance option additional flexibilityinthat variancescanbe appliedfor and granted

### before thevariancetechnology

### is installed, thus ensuringthat the system

### will have a variancebefore 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 arethe basis; forthe latter,smallsystems

### arethe 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 technologiesforthat 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 ofvariancetechnologies. Small system variancesare not availablefor any MCL ortreatment technique for a contaminantwith respect to u.hich a nationalprimary drinkingwater regulation was promulgated priorto 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 determinedthat small system variances would not be available ifthe pre-I986MCL 

### iseitherretained or raised. Small system variancewould onlybe availableifthepre1986MCL was lowered (could apply to updates ofthe existing arsenic and radionuclides MCLs 

### if thepre-1986

### MCLs arelowered). Nor arc small systemvariancesallowableforNPDWRs (including treatmenttechniques) formicrobial contaminants or microbialcontaminantindicators,

### i.e., bacteria, viruses, other regulated pathogens. 

### or regulated indicators, liketurbidity [Section 1415(e)(6)(B)]. Variancetechnologieswere not specified for those contaminantsfor which small system variances are not allowableby the SDWA.
The process for identifying compliance and variance technologies for future regulations was summarizedintheprecedingparagraphs. The languageinthe 1996SDWAAmendments

### is different for the existingregulations. There are two mandatory lists ofcompliance 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 consultationwith 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 Administratorwasrequiredto issueguidanceorregulationsforvariancetechnologiesforthe existing NPDWRs forwhich a small system variancecan be granted. Figure 

### I summarizesthe requirements for compliance and variancetechnologies and differentiatesbetween existingand futureregulations. 

### .



# .

-

# FIGURE 1 

# SMALL SYSTEMREQUIREMENTS COMPLIANCE VS. VAFUANCE TECHNOLOGIES

COMPLIANCE VARIANCE TECHNOLOGY TECHNOLOGY



### -_ EXISTING REGULATIONS: Meet affordable technology criteria SourceWater Quality Endpoint

Health Requirements Separatefrom 

### MCL

FUTURE REGULATIONS: Meet affordable technology criteria SourceWater Quality Endpoint

Health Requirements Separatefrom MCL Not Explicitly Required



### GOOD

MCL



### NONE

Required



### GOOD

MCL

NONE 

### Inherently Required

POOR MaximumReduction that is Affordable Must be protective of public health

Required

POOR Maximum Reduction that is Affordable Must be protective of 

### public health Thetwomajor concernsregarding technologies for small systemsare affordabilityandtechnicalcomplexity. Regarding affordability, per household coststend 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 systemcompliance technologies for existingregulations 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 compliancetechnologies would exist for all ofthe existing regulations regardless of the source water quality. The existingbest availabletechnologies 

### (BATS)or treatment techniques would automatically become the compliance technologies for small systems, which was the case prior to the 1996Amendments. EPA does not believethat resultto be what Congress intended. As a result, EPA will evaluate small systemtechnologiesagainst an affordabletechnology criterion for those existingregulationswhere small systemvariancesorvariancetechnologies are not prohibited by the SDWA. When affordable compliance technologies 

### are idetltified for these contaminants, technologiesthat can achieve compliance but did not meet the affordability criterion will also be identified. This is consistentwith 

### EPA’s approachto the compliancetechnology Iist for the 

### SWTR and the views of stakeholders. EPA will list these technologies and indicatethat they did not pass the affordabletechnology criterionrather than limitthe informationon options availableto systems. For those regulations where the 

### SDWAprohibits 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). 

# -

The flow chart in Figure 

### 2 shmvsthe role ofthe affordabletechnology criteria in the treatment technology arena. The prim*, function ofthe criteria is to determine whether a system of a given size/source water qualitycombination shouldproceed down the compliance or variance technology pathway (assuming an affordablc \.ariancetechnology can be identified). The secondary function is to define the universe of technologies within the compliance or variance technology pathway. These affordable technology critcriaare differentfrom the affordabilitycriteriato 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-levelaffordabilitycriteria”). Optionsthat States can use for system-level affordabilitycriteriawere developed

### inthe 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/OGWDWlsmal1syslafford.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. Technologiesthat 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 ofwater. Ifthese options are not available, grants and exemptions may be available. These issues are discussed in more detailin Chapter4. Therespectiverolesofthe national-level

### and system-level affordability criteria are summarized in Figure 2.-- 

## FIGURE 2 

## AFFORDABLE COMPLIANCE TECHNOLOGIES*

System Out of Complianc

compliance Technology? 

### I

Can YES 

# , system afford NO

__ ~~ a compliance A- technology? /’ 

## ‘> Alt. Source or

, , /’



### i Implement Treatment,

~ Alt Source or I Restructuring / \\

__ 

### -A- ~__ ’/ / \
\ Can System 

### \ IS Restructure 

# ‘ -I/’ Restructur ing

or afford Alt 

# ,)As YES \ practicable? Source? ‘\ /’ / 

# . \\/ NO

__ ~~ 7

-

~ NOI 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 SDWAprohibits small system variances or variance technologies,the candidatetechnologieswill not be evaluated againstan affordabletechnology criterion. There are two statutory prohibitions on small system variancesand one prohibition on variancetechnologies. Aspreviously mentioned. small systemvariancesare not available for any NPDWR for a microbial contaminant (or indicator). The compliance technologies for the six microbialContaminantswere not evaluatedagainstthe affordabletechnologycriterion(EPA 1998b). Small systemvariances are also not availablefor any MCL ortreatmenttechnique with respect to which a NPDWR was promulgated prior to January 1, 1986. Technologies were not evaluated againstanaffordabletechnologycriterionforthe 

### 12contaminantswherethepre-I986MCLhasbeen retained or raised. The statutory prohibition on variance technologies 

### is found in Section 1412(b)(l5)(B)ofthe SDWA. TheAdministrator shall not identify any variancetechnology under this paragraph,unlesstheAdministrator

### has determined,consideringthe qualityofthe source water to be treatedandthe expectedusefullife ofthe technology,thatthevariancetechnology 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, affordablecompliancetechnology determinationswere not done for 

### 3 1 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 affordabilityconsiderationsare not allowed for these contaminants. 

# -

## FIGURE 3 

## COMPLIANCE TECHNOLOGIES (No affordability)"

System Out of Compliance

.



# .

Imp1ement Alt. Source or A 

### -_ Restructuring

~ 

### 7­

,/"an System

I' Restructure or afford Alt

\\/ NO

__ ~ ,1, -\ NO ,,' Are '\.
-~___ ____ . ~ ~. Exemptions *,L-------­

~~ .-L- \..\/ Implement YES Compliance Technology

~ ~ 7-

~ ~ .~.-
~~ Exemption Process (State 

## --r­ sets schedule for compliance

~~

Has exempt ion '> - ~__

_.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 TreatmentUnits as ComplianceTechnologies
Section 1412(b)(4)(E)(ii)ofthe 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 contaminantsinthe 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) stipulatesthat “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 ortreatment technique and equipped with mechanical warnings to ensure that customers are automatically notified of sperational problems.” Other conditions in this section ofthe 

### 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 

### ofthat type shall not be accepted for compliancewith a 

### MCL ortreatment technique unless they are independently certified in accordancewith such standards.”
In order to list POU treatment units 

### as compliancetechnologies, EPA had to delete the part of 40 CFR 

## 8141.101that prohibited POU devicesto be used 

### to comply with an

### MCL. A finalrule was published in the Federal Register on June 

### 11. 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 

### ofexposure. POE devices are still considered emergingtechnologies because of waste disposal and cost considerations. POE devicesmay be included on an updated list in 1999. For more detail on POU and POE devices. seethe 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 ofthe existing non-microbial regulations. It doesnot over-ride any ofthe requirements Iof those regulations. In summary,EPA has chosen to issue the list through a guidance document because regulation development is unnecessary and could considerably delaypublication ofthe 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 toupdate a guidancerather than a rule to incorporate advances in technology performance.
The SDWAdoesnot specifythe content ofthe compliance technology lists. These initial lists (63

## FR 42032) are very general and expand the lists oftechnology options listed in the existing nonmicrobial regulations. These lists may be updated to incorporate new technologies 

### or additional information onparameters that can affect the selection oftreatment. The lists will evolveover time, but will not be product-specific. The compliance technology lists will not be product-specific because EPA's Office ofGround Water and Drinking Water doesnot have the resources to review each product for each potential application; nor does EPA feel it would be appropriateto do so. Information on specific products will be available through another mechanism. EPA's Office ofResearch 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. TheEPA and National Sanitation Foundation International 

### (NSF) are cooperatively organizing and conductingthis pilot project to allow for verification testing 

### ofpackaged 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: StakeholderInvolvement
EPA held a stakeholdermeeting on May 

### 18and 

### 19, 1998. Approximately 50people registered and participated in the meeting. Key stakeholders included States, water systems, and equipment manufacturers. Representatives from nine Stateswere present at the meeting (either at the meeting or on conference lines)and several othersreceived the material that was sentoutprior to the meeting forreview. A draft ofthe "Cost Evaluation of Small SystemCompliance 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 BATSlisted in the regulations, there were few significant commentsonthose presentations.
One major topic discussed at the meeting was the format ofthe document. The two options Iwere separate documents for each Contaminant group or one document with separate chapters devotedto each contaminantgroup. Stakeholderspreferred a documentorganizedby contaminant groupsratherthan by individualtechnologies, since many technologiescan 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 ofcross-overbetweentechnologiesthat 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 optionsthat have technical limitations, stakeholderspreferred EPA to list the technologies along with the discussionsof and guidancefor dealing

### withthese limitations. Examples oflimitationsincludetreatmenttechnologicalcomplexity, which raisesthe concern of whether small systems could successfullyoperate complex processes. Stakeholdersindicatedthat a more comprehensivecompliancetechnology 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 compliancetechnologies. EPAidentifiedcompliancetechnologiesthat didnotmeettheaffordability criteria in addition to those that did, as discussedin Section 

### 1.3.
The initial lists of technologies are not intended to be definitive: systems may choose any technologiesthat meet the requirements ofthe regulations. In each chapter,there are technologies identified

### as “emergingtechnologies”that arenot listed. Thesetechnologieseitherhave 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 additionalinformation regardingthe already listed technologies.
Section 1.7: Organization 

### ofthe Document
This document is organized into several chapters describing the small system compliance technologies for the non-microbial contaminantsregulated before 1996. Chapter 

### 1 discusses the requirements of the 1996 

### SDWA and the approachEPA is followingto meet those requirements. Chapter 2 provides background on the existing non-microbialregulations,including the dates of promulgation. Chapter

### 3 provides a descriptionoftechnologiesthat can be used to treat more than one group of contaminants. Technologies that only apply to one group of contaminants are describedin the chapterdevotedto that contaminantgroup. Chapter4 summarizesthe national-level affordability criteria and describes when and how these criteria were used to identify affordable compliance technologies. Chapter 5 describesthe compliancetechnologiesfor each ofthe IOCs, * includingcorrosion by-products. Chapter 6 describesthe compliancetechnologiesfor each ofthe radionuclides. Chapter 7 describes the compliancetechnologiesfor each of the VOCs. Chapter 8 describesthe compliance technologies for each ofthe SOCs.References Congressional Record. 1974. House ofRepresentatives 93-1185at 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 SenatorDurenberger. [132 

### Cong.

### Reg.]
USEPA. “Four Documents Required Under the.SafeDrinking 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-8I S-R-98-001. Office of Water. September 1998. (EPA 1998b).
USEPA. “Variance Technolog! Findings for ContaminantsRegulated before 1996”. EPA 

### 8 15-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”. EPA

### 8 16-R-98-002. Office 

### of M’rrtcr 1chary, 1998. (EPA 1998e).
USEPA. “National-Level Atf~rdahliry Criteria Under the 1996Amendments to the SafeDrinking 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(1 12): 

### 3 1932. June 1 1

### , 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. Thediscussion ismeanttobriefly describe the relevant parts ofthe charge givento EPA by the 1974Safe Drinking Water Act (SDWA)and its 1986Amendments and tobriefly explain the evolution ofthe National Primary Drinking Water Regulations (NPDWRs) that werepromulgated in response. It is not meant to be 

### a detailed explanation or history of these events, but rather is intendedtoprovidethereaderwith enoughinformationregarding theNPDW 

### sothat he

### or she

### will know which NPDWR is associated with a particular contaminant. It also meant 

### as 

### a catalogue of the Federal Register citations ofthe variousNPDWRs. *



# - Through the SDWA, Congressrequires 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)andtreatment techniques. The legal limits are 

### as protective ofhuman health 

### as is “feasible”, where feasibility 

### is determined by treatment removal efficiencies using the best available technologies,the levels 

### ofthe contaminant found in drinkingwater 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 contaminatedwater and analytical methods are listed. SDWAgivesindividual statesthe opportunity to set and enforce their own drinkingwater standards

### as long asthe standardsare at least 

### as stringent 

### as EPA’snational standards. Most states and territories directly oversee theregulatory programs for water systemswithin 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 1974SDWA 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 ofthese 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 

### fullyenforceableafter 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 1986Amendments required EPA to set Maximum ContaminantLevel 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. includedprovisions for periodic review 

### ofthe data and studiesaffecting the basis ofthe MCLGs and MCLs, and made provisions for allowing variances under specified conditions.
The list of 83contaminantsincluded 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 ensurethe continued adequacy ofthe MCLG and MCL. In 1987,EPA exercised discretion provided by SDWAin substituting ethylbenzene, styrene, heptachlor, heptachlor epoxide, nitrite, aldicarb sulfoxide, and aldicarb sulfone for 

### 7 of the 83 contaminants listed for regulation. EPA choseto regulate the 83 contaminants in phases, according to the availability ofdata and studies supportingthe 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 CopperRule, and the Phase 11-b Rule in 1991,and the PhaseV 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 SDWAonAugust 6,1996. The 1996Amendmentsresulted 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 1996SDWA on futurerules and updates need not be discussed here.
Section2.1 National InterimPrimary Drinking Water Regulations

### (NIPDWRs) (40 59566)
TheNational Interim Primary Drinking Water Regulations (NIPDWRs) were promulgated on December 

### 24, 1975. Thisrule 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 

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

### 2.2: RadionuclidesNIPDWRs (41

## FR 28402)

- The RadionuclidesNIPDWRs were promulgated onJuly 9, 1976. Thisrule established MCLs for combined radium-226 and -228 andtwo classes 

### ofradionuclide contaminants. 

### It alsoestablished 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 isbeing reviewed at the time ofthis writing. 

# i ISection 2.3: Trihalomethanes NIPDWRs 

### (44

## FR 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. Thisrule only applies to community water systems serving 10,000persons ormorethat add a chemicaldisinfectantduringanypart ofthe 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 includedinthe 1975NIPDWRs. ThisruleestablishedanMCL mdsecondary

### MCL forfluoride and applies only to community water systems. The rule also established a. procedure by which public water systemscould 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 fluorideby includingit into the StandardizedMonitoring 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 requirementsfor monitoring, reporting, and public notification for 

### 8 volatile organic contaminants (VOCs). The rule also establishes monitoring requirements for 

### 5 1 other synthetic organic contaminantsnot regulated

### by NPDWRs, ;.e.,unregulated contaminantmonitoring. Therule 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 establishnewrequirements fortheregulation

### of38chemicals, 11ofwhich werepreviouslyregulated underthe 1975NIPDWRs, includingbarium, 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 ofNPDWRs 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 syntheticand volatile organic contaminants

### (SOCs,VOCs) and 7 inorganicContaminants(IOCs). The rule also reproposes MCLs for 

### 5 contaminants. Some of the regulations apply to all publicI

-



# . water suppliesand othersonly tocommunitywater systemsand non-transient,non-communitywater systems.
ThePhase IIb Rule finalizesthe MCLGs and NPDWRs forthe 

### 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 isrequired to be installed to reduce contaminant levelsunder thistreatment technique. As such,

### thereareno complianceor 

### variancetechnologies for

### eitheracrylamideor 

### epichlorohydrin.
On May 27,1992 EPApostponed the effective date ofthe 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 isthe only NPDWR that attempts to minimize contamination introduced by the action ofthe 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 systemsto complete a materials evaluation oftheir distribution system and/or review other information to target homes that are at high risk oflead and copper contamination. Water systemsare requiredto monitor at the tap in these high risk homes, with the number of tap-sampling sites being proportional to the

### -- population served. Those systemswith 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 contaminantsand 

### 5 inorganic contaminants. Themonitoring framework forthese contaminants are in the standardized monitoring framework format. This rule applies to community water systems and non-transient, non-community water systems. TheNPDWR for nickel was revoked.
Section

### 2.9: Summary 

### ofNational Primary Drinking Water Regulations 

### (NPDWRs)
Table 

### 2.1 1 tabulates the variousregulated 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 homepage (http://w\+u

.cpa.go\ 

### OG

### \TI W)

. The homepage has a table (http://www.epa.gov/OG~'I)~~' untappa.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 onthe 

### 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 11Rule 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. 

# 6T 

# 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 

# 1ioc 

# 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 0.5Pentachlorophenol 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

~~ 

# Ioxidation (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 (longerthan 10Pm) 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, EDRBeryllium 

## 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 15pCi/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.

- I3. DESCRIPTIONS

### OF TREATMENT TECHNOLOGIES

### FOR SMALL SYSTEMS
This chapter discusses small systems treatment technologies that can be used for theremoval 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 specialconsiderationsare emphasized where applicable. Small systems treatment strategiesincludecentralized treatment, including package plants, and point-of-use/entry (POUE) technologies. Each strategyisdiscussedin general,then individualtechnologiesare discussed. The choice of strategyto 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,centralizedtreatment refersto both full scaleconventionaltreatment 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 centralizedlocationbefore it entersthe distributionsystem. Centralizedtreatment at more than one entry point 

### is sometimes referred to as “de-centralized treatment”. This point 

### is importantbecause it clarifiesthe differentiation between multiple entry point centralizedtreatment and POUEtreatment. Withinthis document, “centralizedtreatment”will includeboth 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 scaletreatment 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 ofthe treatment process into a compact assembly (such as chemical feeders, mixers, flocculators, basins, and filters), they tend to require lesser constructionand engineeringcosts. Another advantageis that many packageplant technologies are becoming more automated and thus can be less demanding ofoperators than their fully engineered counter-parts(EPA 1990). However, pilot testing requirementscan significantly increase packagetreatment 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 ofhow similarthe situations may be. Sincepilot 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). Sinceit is, ofcourse, essential to confirm that installed treatment is working properly, the need for site specificpilot 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 forpilot testing. It is important to keep in mind that pilot testing needs are specificboth tothe technology in question and to sourcewater quality. For a discussion ofpilot testing needsfor individual technologies, see, e.g., 

### NRC’s Safe Water from Every Tap 

### (NRC 1997).
This need for package plant performance verification iscurrently 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 ofpackage plant units. The aims oftheproject 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 leveragedresources. 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 aspectsofthe 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. Thesetelemetric devicesmay make those technologies requiring a full-time operator more feasible for many small systems. The combined use ofpackage plants and telemetric monitoring and control may well extend many ofthe more complex water treatment technologies to the universe oftechnologies 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 ofthe water entering a household orother building, with theresult 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 waterthat onetap. with the other

### taps servinguntreated water. POE and POU treatment units often use the sametechnological concepts employed inthe analogous central treatment processes, the main difference being the much smaller scale ofthe device itself and the 

### flows being treated. Sometimesthe POEAJ technology uses essentially the sameprocess 

### as its full-scale counterpart, but in some instances process modifications 

### are required to account for the much smallerflowsbeing treated. For example, full-scale filtration technologies often use periodic backwashings to extend the lifetime ofthe filterbed. 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 centralizedtreatment facilit).is not technically or financially feasible for awater system. Regarding POU devices, ifone isplaced under the kitchen sinktotreat food for drinking and cooking, only that water ispotable; water from 

### a bathroom tap would be untreated, and thus exposureto contaminants during teeth brushing. etc.is possible 

### (NRC 1997). In some cases, POU technologiesare simply not applicable, e.g., in cases 

### of \alrrrile contaminantswhich 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 orrwnnccds replacement). Ifthe 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 orcumplc. thc 1998Small Systems ComplianceTechnologies Lists for the Surface Water Treatmcn! Ruk mJthe Total Coliform Rule (EPA 1998a) does not list any 

### POE/U devices for the rnicn1hi.Lconraniinants 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 ofPOEU technologies in the chapters dcrtling \vith compliance technologies for specific contaminants.
Before installing POEk!'treatment units. water systems should evaluatethe units for treatment efficacy and efficiency. For devices that employ cartridges (e.g.. GAC and activated alumina), the NRC (1997)recommends that water systemspilot test to develop estimatesofthe unit's service life fortheirparticular sourcewater. In othercases, evaluationsmay be simpler,e.g., forROit may only be necessary to confirm that membrane fouling will not be aproblem. These concernsare 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 

### forcompliancepurposes (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 systemorby aperson 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 isofcourse essential. After installation, the

### PWS needs 

### awell-defined operation and maintenance program to assurea continuous supply of safedrinkingwater. The

### PWS alsoneeds a routine monitoring program to confirm that the operation and maintenance program is adequate and that the treated water meets drinkingwater 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 temperaturesand consists of amorphous and gamma alumina oxide. AA isused 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 surfacehydroxides 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 sequenceofrinsing 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 sodiumhydroxide. 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 solutionpH. AA isnot charged at a pH 

### of9.5, ispositively 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 anionsotherthanthe target compoundsintheraw water must be evaluated for each sourcewaterthat 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 

# aqmuch ofthe operating cost ofthis 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 requiredto operate AA. Stakeholdersagreed that small systemswould not likelyregenerate onsight. Regenerating themedia off-site or disposingofthe spent media may be possibilities. Small systems should also be concerned about highly concentrated waste streams.


### Activated 

### Carbon
Activated carbon is similarto charcoal 

### in composition, but is surfacially altered to enhance its sorptionproperties. The base carbon material (typicallybituminous coat, lignite, petroleum coke, orbone 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 ofmercury. (Snoeyink 1990.

### NRC 1997.AWWA 

### - ASCE 1998).
Granular activated carbon (GAC)
GAC treatment removes contaminants iiathe physical and chemical process of sorption,by which the contaminantsaccumulate at thc carbon surface 

### asthe water passes throughthe carbonbed. Removal efficiencies for many organic contaminants are excellent under ideal circumstances, but can be significantly affected by nimrquaiif!. parameters, like dissolved natural organic matter levels,pH, and temperature. Remo\al ctficicncies change drastically oncethe bed nears exhaustion. At exhaustion,contaminant breakthrough occurs. which is often defined asthe 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 toensure proper removals (Snoeyink 1990).
Information regarding GAC contactor contigurations, operationalmodes,and design factorscan be found in many sources (e.g.. AL\'\\'.+I 1990. EPA 1990,Snoeyink 1990,AWWA

## - ASCE 1998). Operatingproblems 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 flowrate, and controlling biologicalgrowthinthecarbonbed (AWWA

## - ASCE 1998).
GAC often requires pre-filteration to remove particulatematter fiomthe sourcewater 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 ofthis latter approach is that fiequent backwashing ofthe column 

### is required. Backwashngmay cause spent carbon to comeinto contact with the treated water: ifthis can be tolerated, then the technology is straightfonvard and compact (NRC 1997). Competitive sorption can also significantly affect the removal efficiency ofan 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 ofGAC needed to achievethe optimal efficiency. Competing organic compounds can also displace (cause the desorption of) contaminants. If influent water quality changesresult in a high concentration ofthe competingcompound. the contaminantdesorptionprocess may temporarily causethe contaminant level inthe effluentto 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 flowsthrough one column, rather than through 

### two or more in series)must be monitored to ensurethat breakthrough doesnot occur. If an exhausted GAC column is not regenerated or replaced, desorption may result in the effluenthaving higher concentrations 

### ofthe contaminant than the untreated water. Monitoring for some organic compoundsmay require an advanced operator or the services of an outsidelaboratory. In general, GAC is straightfonvard to appl!. on a small scale. Small columnsmay be easily obtained and installed. If virgin carbon isrequired (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 sameway as GAC. The main difference is the mode ofapplication and the grain size ofthe activated carbon. PAC grains areten 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 asGAC. The carbon powder is added directly to the raw 

### user line or to a mixing basin. 

### For efficient removals, all ofthe 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 ofthe 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 ofthe 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 ona small scale ifthe plant already has a treatment train in place that includes mixing, precipitation or sedimentation. and filtration.
PAC may adsorb somechemicalsthat are added duringthetreatment process, e.g., chlorineand potassium permanganate. For this and other reasons, the best point of application isusually at the head ofplant, either in the source water pipeline or in a mixing basin (AWWA

# - ASCE 1998).
Air Strippiny (Aeration)
Air stripping, or aeration, involvesthe continuous contact ofair with the water beingtreated, allowing volatile dissolved contaminantsto transfer from the sourcewater 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 takesplace. The amount ofpossible 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 ofthe aeration system. e.g., aidwaterratio. The Henry’s Law coefficient is a commonly used indicator of thetendency ofa contaminanttopartition 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 ofthe rate oftransfer, which depends on both the properties ofthe contaminant, the site specific conditions, and the aeration design. e.g., an effectivecontact 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 

### ofthe contaminant; influent concentration ofthe 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 shallowtray aerators, spray aerators, mechanical aerators. and gas permeable membrane aerators.

The Henry’s Law coefficient (HJ canbe defined any number ofways, and so can be reported in various units. Here, we are assuming that H, =C, / 

### C,, where 

### C, is the concentration ofthe contaminant in air at equilibrium with Cw, the concentration ofthe contaminant in water. 

# .Packed tower aerators
In packed tower aerators (PTA). the contaminated water flows downward by gravity over a bed ofpacking material such 

### as fixed plastic grids, looseplastic rings, or loose ceramic saddles, while air is blown upward through the column. Thepacking material breaks the surface area for contact between air and water thus promoting transfer ofthe contaminant into the gaseous phase.
Theremoval efficiency ofcontaminantsusing PTAs dependsupon 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 

### isrequired to remove a contaminant from water. However, air to water ratios used to achieve a givenremoval efficiency are greater than the ideal system.
The contact time is a function ofthe depth ofthe packing material. 

### As the depth ofpacking 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 airpassing through the column must be considered M hcn selecting packing materials.
The water loading rate is the amount ofwater that passes through the tower and is largely a function 

### of diameter ofthe 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 consistsof 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
Diffusedaeration (DA) is the process ofbubbling air into a water-filled contact chamber through a diffusermechanism located at or near the bottom ofthe chamber. The chamber can eitherbe a column or basin. The efficiencyof diffusedaerationforremoving organics depends upon the diffusertype, air-to-waterratio, depth ofthe water in the contact chamber, detention time, and water temperature. Diffusedaerators are generallyused only to adapt existing plant equipment. Multi-stagebubble aerators (MSBA) are a form of commerciallyavailablepackageplant. These are a variationtothe traditionaldiffusedaerator. Typicalcommercialunits consist of a high-densitypolyethylene vessel partitioned intomultiple stageswith 

### an individual aerator for each stage. MSBAs are compact, with water depthstypically lessthan 1.5 

### ft (comparedto depths of 10to 

### 20 

### ft fortypical aerationbasins). Ifhousing is required forthe aerationunit, MSBA’s compactness can be very attractive. Other advantagesofMSBA includeremoval efficienciesthat are competitive with PTA.
The advantages 

### ofa diffuser aeration system is that an existingbasin or storagetank can be modified to be used as a diffuser aerationunit. Due to reduced pumping costs,

### no packing material costs, and potentially lower energy costs,marginal savingsmay be incurred. However, an increasein contacttime and air-to-waterratiosmay be needed to achievegood removals because DA generally does not provide for convectivemovement ofthe water and thus does not allow asmuch contactbetween the air and water as othermethods. 

### Point-Of-Usepoint-Of-Entrv Aeration Technoloeies
Point-of-use aerationtechnologies are not practical for volatilecontaminantsbecause routes ofexposure can occur through inhalation,directcontact,and ingestionfrom a secondary faucet. Therefore,

### POU aeration technologiesare not consideredfor compliancetechnology listing.
Air stripping technologies such asPTA and diffusedbubble aeratorshave been used in 

### POE systems to remove 

### VOCs from ground water (NRC 1997). Similarto other aeration technologies,these systems rely on mass transferto remove VOCs from water. While 

### POE aeration is technically feasible, it is not commonly used forpublic water systems and may not be as cost effective as other aeration systems.



# bd 

# 34 .

### -- MultiDletray aerators Tray aerators (Cornwell 1990,AWWA-ASCE 1998)consist of a series oftrays with slats, perforations, or wire mesh bottoms over which water flows and collects at the base ofthe unit. Thethin film of water formed asthe water flows over the media provides a large surface area for mass transfer ofthe contaminant from water to air. These aerators canbe 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.
Shallowtray aerators (STA) are another form of low-profile package plant. In STA,the contaminated water flows alongthe trays while air is blown through hundreds ofholes in the bottom ofthe trays, creating a large mass-transfer surface area where contaminants are volatilized. Theseunits are analogousto MSBA in terms oftheir 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 ofthe contaminants. One disadvantage isthat 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 ofthe 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 dropletsproduced 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 ofthe water droplets formed (area for mass transfer), height of spray (contact time), and temperature. The advantagesof 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 isthat they are adaptable to existing basins, and are often installed as a systemretrofit. However, these units are not as efficient as other aeration units. Because 

### ofthe limited contacting systembetween air and water, large basins, long residence times, and high energy inputsmay be needed to increase the efficiency ofthe aerator. These systems are applicable when lowlevel 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 (Semmenset al.; Zander et a]. 1989). Water flows through the interior ofhollow 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 ishighly 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 eventhough the effectiveness

### ofthe process varies for each contaminant, aerating to remove one specific contaminant will also reduce concentrations of the others.
Air StriDpingLimitations
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 ofthe 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 ofthe aeration units.CoaPulation/Filtration

- Coagulatiordfiltration (C/F)processes involve the addition of chemicals like iron salts, aluminum salts, or cationic polymersthat 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 stepbefore 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 sedimentationor 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 ofthe treatment traih may vary in design criteriabetween systems. Most ofthe concerns regarding conventional filtration are specific tothe SurfaceWater Treatment Rule (SWTR) and are discussed elsewhere 

### (EPA 1998~). The main issue isthat conventional filtration does not work properly ifthe coagulation chemistry is incorrect, so that operator skill is ofparamount 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 isthen 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 ofthe filtrateto the point of use. Gravity units have the advantage 

### of allowing easy visual inspection ofthe 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 ofdirect filtration and consists offilters 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 selectiveremoval ofcharged inorganic species from water using an ion-specific resin (AWWA 1990,

### AWWA-ASCE 1998). The surface ofthe ion exchangeresin contains charged functional groups that hold ionic species by electrostatic attraction. As water containing undesired ionspassesthrough a column ofresin beds, charged ions onthe resin surface are exchanged for the undesired species in the water. Theresin, when saturated with the undesired species, isregenerated with 

### a solution ofthe exchangeable ion. A large variety of synthetic resins is available for specific applications. 

# . Generally,resins can be categorized 

### as anion exchangeorcation exchange resins. Anion exchange resins selectively remove anionic species such asnitrate 

### (NO?) and fluoride 

### (F-). Anion exchange resins are often regenerated with sodiumhydroxide or sodium chloride solutions, which replace the anionsremoved from the water with hydroxide 

### (OH-)or chloride (C1-)ions, respectively. Cation exchange resins are used to removeundesired cations from water and exchangethem for protons 

### (H-). sodium ions (Na’) orpotassium ions 

### (K).
Water to be treated by 

### IX must be low in solidsto 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. Thepresence of such species may reduce removal efficiencics 

### (NRC 1997).
An operator must monitor the s!’stem 

### to determinethe extent ofresin saturation orthe breakthrough 

### ofthe 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 tothe systems full-time)

## td assure proper operation.
In either the cation or anion exchangeprocess, 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).
Stakeholdersrequested that EPA statethat 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 ofthree beds in series:two in production and one in regeneration mode at any given time. When exchange capacity ofthe 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 ofthe 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 ofthe IX bed and reduce leakage 

### (EPA 1995).
IX 

### is a common water treatment technology for small systems. IX is available in the form ofpoint-of-use 

### (POU) and point-of-entry 

### (POE) devices as well as in the form of full-scale treatment. An advantage to IX isthat it canbe used under fluctuating flowrates 

### (NRC 1997). The technology doesproduce 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 isthe regeneration frequency, and competition with other ions will affect the run length. For example, anion exchange would be recommended primarily for small ground water systemswith low sulfate and 

### TDS.
Lime softenin?
In the lime-softening 

### (LS) process, the pH ofthe water beingtreated israised 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 ‘latherspoorly 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 ofthe chemistry of 

### LS may make it too complex for small systemsthat use surface water sources. 

### LS may be more appropriate for small systems that use ground water because ofthe relative uniform quality of ground water. Once the softening chemistry for a ground water is determined, it should not changemuch. In comparison, chemical additions to surface waters need 

### to be modified frequently in response to water quality changes 

### (NRC 1997).
One ofthe difficult aspects of

### LS is the operation and maintenance of lime feedersand lines carrying lime slurry to the point of application. In addition, plant operators must understand lime softening chemistry. Measurement ofpH 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 similarto coagulatiodfiltration in that pre-fabricated equipment isavailable. 

### 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 wouldenable 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/electrodialysis reversal (EDEDR). All ofthese processes share certain characteristics,sincethey 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 selectionof membrane treatment for a particular drinking water application 

### is determined by a number of factors, including: targeted material(s) to be removed, sourcewater quality characteristics, treated water quality requirements,membrane pore size, molecular weight cutoffj(MWCO), membrane composition, and systedtreatment configuration (Jacangelo 199

### 1).
In general, membranceprocesses show little economy 

### of sde,since capital costsper 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 littlemore than a feed pump, a cleaning pump, the membrane modules, and holding tanks (NRC 1997). Membrane technologies can be more costeffectivethan more conventional treatments for controlling a host ofwater quality problems (Wiesner et ai. 1994, Bergman 1996).
Ultrafiltration and Nanofiltration
Ultrafiltration and nanofiltration are “membrane filtration” processes, in that they work by excluding contaminantsdue 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 standardsvary between manufacturers. For example, one supplier may classify a membrane as nanofiltration,while another supplier may classify a similar membrane asultrafiltration. Also, some manufacturers refer to average pore size and some to maximum pore size. For these reasons, water systems should make surethat 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 ofthe molecular weight ofthe smallest molecule that will be retained by the membrane. *The operation 

### of ultrafiltration and nanofiltration processes are substantially less complicated than the operation ofthe treatment trains needed to achieve similar removals via conventional technologies. In particular, membrane processes may be very appropriate for small systems attemptingto remove multiple contaminants. Ifpre-treatment is required, the complexity ofthe required operations can of course increase appreciably. In addition, specific sitetesting to analyze the potential for organic foulingmay be required. However, there are few limitationsto the types 

### ofraw water that can be handled by membrane processes and, ifneeded, 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 somecases, microbiological contaminants 

### (EPA 1990,Logsdon et al. 1990,NRC 1997,AWWA-ASCE 1998). ROresembles 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 involvesthe use of applied hydraulic pressure to oppose the osmotic pressure4across a non-porous membrane, forcing the water from the concentrated solution sideto the dilute solution side. Sincethe membrane is non-porous, the water doesnot 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. ROproduces 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 efficienciesfor 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-smolecular 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 ifthe influent is not pre-treated, depending upon the quality of the raw water (AWWA-ASCE 1998). Influent total organic carbon 

### (TOC)levels can be ashigh as 

### 20 mg/L without requiring pre-treatment (NRC 1997),but the influent have low turbidity, iron, manganese, and chlorine orpre-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 sideof 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.
Sincethepermeate has very low mineral content and alkalinity, it can be quite corrosive. Theusual 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 adjustmentthrough the addition of a chemical base, like sodium hydroxide. Post-treatment disinfection 

### is also a commonpractice. Usually, RO systems have automatic backwash features, reducing laborrequirements. The skill requirements for the daily operation of common pre-treatment processes are often greater than the membrane process itself. However, periodic cleaning ofthe membrane surfaceis required. Caremust be taken to avoid contaminationofthe raw or finished water with the acidic post-wash solution. Also, the membrane should be flushed with permeate toprevent later scaling. Ifthe plant istaken out of operation for days at a time, themembranes should be filled with a disinfection solutionto 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 processesto concentrate salts from the feed water into smaller-volume, higher-concentration solutions within collection channels. 

### ED and EDR systemsconsist of stacks of alternating anionic and cationic selectivemembranes. The ionic constituents pass through the membranes in response to an electric current applied perpendicularly tothe membrane surfaces. Thisresults in an alternating sequence of de-mineralized water streamsand concentrate streams (NRC 1997. AWWA 

### - ASCE 1998). The principal difference between ED and EDR isthat EDR involves the additional step of a change 

### in electrode polarity every 

### 15to 

### 20 minutes, causing a reversal in ion movement. This step minimizes scale buildup onthe membranes and thus EDR can operate for longer time periods between cleanings. The majority ofplants using ED technology in the United States use EDR (NRC 1997).
ED/R systems require feed water pre-treatment. Cartridge filtration is oftenthe minimum requirement. Turbidity should be less than 

### 2 NTU, free chlorine levels less than 0.5 mg/L, manganese less than 0.3mg/L, and hydrogen sulfide lessthan 0.3 mg/L (Conlon 1990). Total dissolved solids up to 4,000 mg/L have been successhllyhandled 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 theproduct water. Standardsfor these contaminantsmust 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 ofthe product water. ED/R systems usually operate at 70%recovery (NRC 1997).
A principal disadvantage of EDRis the high energy consumption. Pumping costs are similar to costs for ultrafiltration, but process power costsroughly equal pumping costs for ED/R.
More than half ofthe EDRsystems in operation inNorth America servefewer than 

### 3,500persons, with some serving fewer than 

### 200, Since ED/R plants are amenableto 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 significantproblem in some areas, sincewaste 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 ofthe concentrate into the source water may be feasible. Other alternativesinclude 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 ofthe process involves obtaining regulatory permits. In the vast majority ofcases, an acceptable waste disposal method can be successfully implemented and permitted (Pontiuset al. 1996). Disposal of RO and EDRreject water poses a potentially more seriousproblem than the membrane filtration processes, because ofthe large concentrate volumes. Municipal sewer disposal and deep well injection are conventional waste handling strategies. Theuse of evaporation ponds is another possibility, but isnormally used only when conventional means are not possible, because ofthe 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 ofMembrane Softeningin 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’h ed.. 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:ReviewJournal ofthe International Water SupDlvAssociation. 

### Vol. .9,Numbers 3/4. 1991. % Lamarre. B. Selecting an Air Strimer-What to Consider. TheNational Environmental Journal, July/August. 1993. Logsdon. 

### G.S., Sorg,T.J., and Clark, B.M. “Capability and Cost ofTreatment 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 Serviceto Small Communities. Committee on Small Water Supply Systems. Water Scienceand 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 ofthe American Water WorksAssociation 8l(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. “Technologiesfor 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 Systemsto Implement Drinking Water Regulations: Report to Congress”. Office of Water. EPA 810-R-93-001. September 1993.
USEPA “Summary ofArsenic Treatment Workshop”, January 18, 1994.
USEPA. “An SABReport: Review ofIssues Related to the Regulation 

### ofArsenic in Drinking Water”, EPA-SAB-DWC-95-015, July 1995.
USEPA. “Technology Transfer Handbook: Management ofWater Treatment Plant Residuals”. Office of Research and Development. EPA/625/R-95/008. April 1996.
USEPA. “Announcement 

### of Small Systems ComplianceTechnology 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 Office of Water. September 1998. (EPA, 1998c) 1. 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 evaluatetechnologiesfor each small size category against an affordable technology criterion for thoseregulations 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 distinguishthe national-level affordability criteria from the affordability criteriathat Stateswill use for determinations affecting individual systems. EPA published informationregarding these “system-level affordability criteria” inFebruary, 1998 (EPA 1998a). This information was required by Section 1415(e)(7)(B) ofthe SDWA. There arethree provisions ofthe SDWAthat refer tothese “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 SDWArequirements. Small systemscould receive as long 

### as nine additional years to comply. Finally, Section 1452(b)provides that affordability on a per household basis shall be one ofthe 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, Statescan 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 systemsmeeting aNPDWR would likely be lowerthan the threshold used to determine when a system would operate at a level that does not provide an equivalent level 

### ofprotection as meeting the 

### MCL.
The national-level affordability criteria used to determine ifthere 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 ofcompliance with a NPDWR cannot afford any ofthe 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, 1998may continueto get renewals oftheir exemptionsuntil the exemptionperiod has run out. That means that a small system can have no more than 9 years afterthe Section 141

### 2 compliance date to meet the applicable MCLhreatment technique even ifthe exemption was issued prior to the 1996 SDWA Amendments.
To determine ifthere are any affordable compliancetechnologies for a givenNPDWR,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 ofmeasure for both parameters. The selected approach was to measure user burden asthe increase to annual household water bills that would result from installation oftreatment. 'For community water systems, the household was selected asthe most sensitive user for cost increases (EPA 1998b). Non-community water systems 

### (NCWSs) were also evaluated by comparingtheir vulnerability to cost increases with households in community water systems. The conclusion,based onthis comparison,was that the categories ofNCWS 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 ofthe methodology used to determine the national-level affordability criteria is described below. Thehousehold isthe focus ofthe national-level affordability analysis. Treatment technology costs arepresumed affordable to the typical household ifthey can be shownto be within a range (defined as a range ofpercentages ofmedian household income) that appearsreasonable when compared to other household expenditures. This approach is based on the assumptionthat affordability to the median household served by the CWScan serve as an adequateproxy for the affordability oftechnologies to the system itself. EPA has chosen to expressthe water system financial and operational characteristics using their median values, which is a measure oftheir respective central tendencies. EPA believes that the national-level affordability criteria should describe the characteristics oftypical systems and should not address extreme situationswhere costs might be extremely low or excessively burdensome.
After selectingthe impacts onhouseholds asthe measure for comparing national-level affordability and treatment costs. a consistent set of units was needed to make the comparison. Thetreatment cost models produce rate increases measured in dolladthousand gallons ($/kgal). Annual household water consumption is needed to convert the treatment technology costs into the increase in annual household water bills. The water consumption estimates were multiplied by 1.15to account for lost water due to leaks. Sincethe water lost to leaks is unbilled, the water bills for the actual water used needed to be adjusted to cover this lost water by increasing the household consumption. Multiplying the rate increase by the adjusted annual household consumption yields the increase to annual household water bills ($/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 ofinfrastructure repair (mains and service


# 47lines) 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, sotreatment costs for many ofthe regulated contaminantsmay already be accounted for in thebaseline.
The affordability threshold was determined by comparing the cost ofpublic water supply for households with otherhousehold expendituresand risk-averting behavior. National expenditureestimateswere derived to illustrate the current allocation ofhousehold income across a range of general household expenditures. This consumer expenditure dataprovided a basis for determining the affordability threshold by comparingbaseline household water coststo median household income 

### (MHI)to determine the financial impact of increased water costs on households.
There are 

### three parametersneeded for each sizecategory 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 consumptionand the current annual water bills were derived directly from data in the 1995Community Water System Survey (EPA 1997a,EPA 1997b). The MHI data were derived by linkingthe CWSS data with data in the 1990Census 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 billsranged 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 summarizesthe national-level affordability criteria and showsthe 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 ofthis magnitude if a compliancetechnology was installed. Many compliance technologies impose substantially lower household costs. For example. the screeningprocess examined several technologies that imposed lessthan $300/household per year increases in all three size categories. Appendix 

### F of the “National-Level Affordability CriteriaUnder the 1996Amendments 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 StateRevolving Fund loans or other sources. This financial assistance could also reduce the impact on householdsin those systems that qualify for financial assistance. For more detail on the national-level affordability criteria, see the “Variance Technology Findings for ContaminantsRegulated Before 1996”(EPA 1998d) and the National-Level Affordability CriteriaUnder the 1996Amendments to the Safe Drinking Water Act” (EPA 1998b)documents. 

## -1Section

### 4.2: Affordable Technology Analysis usingNational-Level Affordability Criteria Compliance technologies were evaluated against the national-level affordability criteria for those existing regulations where small systemvariances or variance technologies are not prohibited by the 

### SDWA. When affordable compliancetechnologies are identified for these contaminants, technologiesthat can achieve compliance, but did not meet the.affordability criterion will alsobe identified.
In general, technology cost estimatestotreat all ofthe water were compared against the available expendituremargin 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 onthis analysis, an affordable compliance technology was 

### found for each ofthe five contaminantsfor 

### all system sizes and expected source water qualities. For most ofthe system size/source water quality combinations, there are multiple affordabletechnologies.
The national-level affordability criteria only played a role in removing some

### ofthe Options in the smallest sizc catcpries. Thetechnologies 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 ofthe water for this analysis, systems requiring lower removals ma) hittut the ”other compliance technologies” would pass the national-level affordabilit! criteria 11‘3lower removal efficiency is required. A portion ofthe influent water could be trcrt~ccf and 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 considerthe “other compliance technologies” under thosc ciriuni~tmic~.

### -- References
USEPA. “Community Water System Survey Volume 1:Overview”. EPA 

### 8 15-R-97-001a. Office of Water. January 1997. (EPA 1997a).
USEPA. ‘‘Community Water System Survey Volume 11: Detailed SurveyResult Tables and Methodology Report”. EPA 

### 815-R-97-001b. Office ofWater. January 1997. (EPA 1997b).
USEPA. “Information for Stateson 

### Developing.Affordabi1ity Criteria for Drinking Water” EPA-8 16-R-98-002. Office of Water. February, 1998. (EPA 1998a).
USEPA. “National-Level Affordability Criteria Under the 1996Amendments 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. ‘‘AnAssessment 

### of the \’ulnerability ofNon-Community Water Systemsto SDWA Cost Increases”. Prepared b!, Science Applications International Corporation for the EPA. July 1998. (EPA 1998~).
USEPA. “Variance Technolop Findings for ContaminantsRegulated before 1996”. EPA 815- R-98-003. Office of b’atcr. Scptcmhcr 1998. (EPA 1998d).
USEPA. ”Announcement of‘Snul I S) stems Compliance Technology Lists for Existing National Primary Drinking Warer Kcgul;ltion\ and Findings Concerning Variance Technologies”. Federal Register. 63(15I 420;2 .August6, 1998. (EPA 1998e).5. SMALL SYSTEMS COMPLIANCE TECHNOLOGIESFOR INORGANIC CONTAMINANTS, INCLUDING CORROSION BY-PRODUCTS
Section 5.1 : BackPround
Seventeen inorganics areregulated. 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 

### 2001. The final rule for fluoride was promulgated in April 1986. Thefinal rule forthe Phase I1 inorganics (asbestos, cadmium, chromium, mercury, nitrate, nitrite and selenium)waspromulgated in January 1991. The lead and copperrule was promulgated in June 1991. The final rule for Phase IIb (barium) was promulgated inJuly 1991. The final rule for the Phase V inorganics (antimony,beryllium, cyanide and thallium) was promulgated inJuly 1992.
Issues with compliancetechnologies for inorganics treatment are discussed in Section 

### 5.2.2. A general description ofthese technologies can be found in Chapter 

### 3. Corrosion control technologies arerelevant for inhibiting lead and copper dissolution inthe 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 liststhe compliance technologies for small systems and Section 

### 5.4 describesemerging technologies.
A short description of some ofthe 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 ofplumbing 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 ofresidences and other buildings. In some cases, copper is a component of additivesto drinking water used by systems to control the growth of algae (EPA 1991a).
Asbestos:
Asbestos fibers are relatively large particles. Asbestos fibers are generally oftwo 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 onthe order of 0.4 to 1.7microns in length and 0.1 to 0.4 microns in width (Logsdon 1979,Kirmeyer 1979a,Kirmeyer 1979b,Black & Veatch 1975). Because ofthe large size ofthe particles, the potential for using inexpensive membrane technologies exists. However, further research is required.Antimonj.: Antimony isfound in over 100mineral 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 statesin 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 effectivein 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 ashigh as 9 to10 mg/l are not uncommon in some ground waters (Benefield 1982). Fluoride hasbeneficial and detrimental effects. It can helpprevent 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 ofthe teeth and bones. The 

### MCL for fluoride is4.0 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 fluorosiswhile still allowing for the beneficial effects of fluoride (EPA 1986a).
Nitrate:
Nitrate is a common ion found in most natural waters. It isthe end product 

### ofthe 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 

### 10mg 

### 'I of nitrate (asNitrogen). Well water. particularly shallow well waters. tend to have higher concentrations of nitrates than surface waters. The major sources ofnitrate 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. Groundkvatersgenerally 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 speciespresent, oxidation to arsenate may be required to achieve the desired removal.



# 53Section 

### 5.2 Evaluation 

### ofTechnolopies
Corrosion Control Technologies
There areprimarilythree differentapproachesto control for corrosionin the distribution system. One approachis to cause a calcium carbonateprecipitateto form insidethe distribution system to protect the insideofthe pipes. Another approach,referredto aspassivation,is to change the water to be less corrosivewithout causing a precipitateto form. There aretwo methods of passivation. The first isto change

### the alkalinity and pH ofthe water. The second

### is to add 

### an inhibitor 

### (EPA 1992). Thethird approachto controlfor corrosionis to use aeration.
Calcium carbonate precipitation
The principlebehind calciumcarbonateprecipitationis to maintain the concentration

### of calcium and carbonatehigh enough inthe product water 

### sothat cakium carbonateprecipitates out in the distribution system. The solidsform a protective coating. This approachis only practical if the concentrationofthe calcium and carbonateare high enough in the influentwater. If necessary, calcium can be added in the form ofhydrated orquick lime. The carbonatecan be adjusted by adding soda ash, sodium bicarbonateorcarbon dioxide. The pH can be adjusted,if necessary, by adding these aforementionedchemicals and/or caustic soda,hydrochloricacid or sulfuric acid. Small system; should be aware ofthe complexitiesinherent in using lime and soda ash systems. These methods require a high degree of operator attentionbecause 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 systemsmust be acid cleaned. Small systems shouldalso be aware of complexities in operating a sodiumhydroxide system. 

### In additionto avoiding calcium carbonate plugging 

### ofthe sodium hydroxide feed system, small systems should alsobe aware that employees may have to handle a strongbase; sodium hydroxideis usually deliveredas a 

### 50 percent solution 

### (EPA 1992). Stakeholdersexpressed a concernthat this approachmay also cause a build-up ofprecipitatein consumers’hot water heaters.
This control strategy

### is only appropriatefor lead. 

### It is not an effective strategyfor copper for several reasons. First, a much larger surfacearea would need to be coated. Second,a calcium carbonate film may not establishon copperpiping. Third, adjusting alkalinityfor precipitation may produce a high alkalinityfinishedwater which can be corrosiveto copper.

### -- Passivation
The other approach to corrosion control is passivation. In this case, the goal isto produce less corrosive water. A precipitate need not be created. Alkalinity and 

### DH
One method ofpassivation isto alter the alkalinity and the pH. This is appropriate when the water is not very hard and low in alkalinity.

I This essentially involvesuse ofthe same chemicals (lime. soda ash. etc.) and feed systems asin calcium carbonateprecipitation. An advantage ofthis approach isthat 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 applicableto the smaller systems is the use of limestone contactors (EPA 1987). This method would be applicable ifthe raw water was soft and slightly acidic. With this technology, the water flows through and dissolves a packed bed 

### ofcrushed 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. Thistechnology is primarily recommended for the smallest category 

### (25-500only). Stakeholdersexpressed a concern that limestone contactorsarepresently not widely in use. Inhibitors
The other approach 

### to passivation for corrosion control isto use inhibitors. These are usually phosphate or silicatebased. Theprincipal type ofphosphates used are orthophosphates; all are measured as orthophosphate asresidual. Polyphosphates have a record of successful corrosion suppression in some waters. but in othersthey can increase corrosivity. Polyphosphates are primarily used as sequesterants. The chemicals are not dangerous,have a long shelf life. and are highly soluble. Small systemswould be ableto 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 affectspH and dissolved inorganic carbon (DIC), theparameters 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 lessthan about 

### 4 to 

### 10mg/L 

### CO, are not suitablefor aeration. Mineral precipitation brought about by water quality changes resulting from aeration may present operational constraintsunder some conditions. Aeration produces consistent water quality and may be advantageous to smaller utilities because ofrelatively low costs and simple operational and maintenance needs (Lytle et 

### al, 

### 1998). ComplianceTechnolopies for Inorpanics
Activated Alumina
In the application of 

### activated alumina (AA) fortreatment ofinorganics such asarsenic, 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 uhich 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 systemshave 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 3rdwlturic acid)may be difficult for small system operatorsto handle. Consequently. small \! \tern\ \\ill likely need to regenerate the media off-site or dispose ofthe 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. Spentregenerant from arsenic treatment cannot IihcI! bc discharged to a sanitary sewer without pre-treatment.

# .

- Coapulation/filtration

- Coagulatiordfiltration (C/F) units are available aspackage plants, however, it may not be advisableto install a C/Funit solely for inorganics removal. It may be a relevant technology if the raw water is also high in turbidity. Stakeholders mentioned that somemanufacturers are making C/F units solely for arsenicremoval. Stakeholders also expressed concerns about solids handling. For instance, disposal of arsenic contaminated sludgemay be an issue, especially ifit is deemed hazardous. Sludges

### are evaluated by the toxicity characteristic leachingprocedure (TCLP) to determine if a sludge should be classified ashazardous. Sludgesfrom four different water treatment plants were evaluated (Bartley 1992)for a variety ofinorganic contaminants, including arsenic. One plant had a 

### C/F process, one plant had a C/F and LSprocess, and two had LS processes. All TCLP extractswere 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 systemshave 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 belowthe criterion for being designated a hazardous waste.
Ion exchange
In considering application of ion exchange (IX) for inorganics removal, it isimportant to understand what the effect of competing ions will be, and to what extent the brine can be recycled. Similar to activated alumina, ion exchangeexhibits a selectivity sequence, which refers to an order in which ions are preferred. Table 9.2 in Water Quality and Treatment (AWWA 1990)showsthe most preferred ions (i.e. those with the highest separation factors) at the top ofthe 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. Thepresence of 

### TDS also impairs aresenic removal. Source waters with 

### TDS levels above 500 mg/L and sulfate levels above 120mg/L are not amenable to 

### IX treatment (EPA 1998a). Spentregenerant 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 asmany as

### 25 times (Clifford 1998). Though ion exchange (IX) is an affordable. effectivetreatment 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 120ug/l after processing 700bed 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. IReverse osmosis
A concern with reverse osmosis 

### (RO) for inorganics treatment isthat ifthe full stream is treated, then most ofthe alkalinity and the hardness would also be removed. In this case, posttreatment may be necessary to avoid corrosion problems. Iffeasible, a way to avoid this issue is to blend the water rather than treat the full stream. The amount of water that isrejected is also an issue with 

### RO. Discharge concentrate can be between 

### 10and 

### 50percent 

### ofthe influent flow (EPA 1998a). For that reason it may not be 

### an appropriatetechnology for 

### all parts ofthe 

### U.S. RO involvespassing water through a semi-permeablemembrane by forcing the water from the concentrated solution sideto 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 ofthe small pore size, 

### RO can remo\re both As(II1) and As(V). However, as with the othertreatment technologies, 

### RO removes As(V) to a greater degree than As(II1). Consequently pre-oxidation will improve removal efficiencies. For asbestosremoval, 

### RO and ultrafiltration techniques have problems with asbestos fibers accumulating 

### onthe 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 

### ofthe contaminant toa 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~midc is 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 sincethe chlorination should he conducted at a pH greaterthan 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 isprescribed over simple chlorination because ofthe need to destroy cyanide and cyanogen chloride asquickly aspossible.Corrosion control
In addition to preventing dissolution of lead and copper, corrosion control is relevant for inorganicsremoval 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 asbestosremoval and can achieve 

### 95% removal. In the application ofthis technology, proper chemical pretreatment isnecessary. The chemical treatment may consist of conditioning the feed water with alum or iron coagulants and addition ofpolymers 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 ofparticles in the water and filter breakthroughs (EPA 1986b). Diatomaceous earth filtration
Diatomaceous earth filtration is a compliance technology for asbestosremoval and capable of 95%removal. Improved remot.al of asbestos fibershas 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 anionicpolymer isthen applied. Similar conditioning ofthe diatomite used tor body feed, by the continuous addition of a polymer to the raw water. also improves the fiber removal efficiency (EPA 1986b).
Granularactivated carbon
Granular Activated Carbon (GrIC) is a compliance technology for treatment of mercury. GAC columns are used in water treatmcnt systemsprimarily for the removal oforganics 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 Electrodialysisreversal (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 ofthe 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 compliancetechnologies 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 isnot likely to be an issue with POU

### RO (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 ResearchDivision (DWRD) conducted POU studies in Alaska and Oregon where POU-RO and POU-IX were demonstratedto be viable treatment alternatives. DWRD entered into a cooperativeagreement with San Ysidro, New Mexico to study POU-RO-removalof arsenic, fluorideand other contaminants. Again, POU units were shown to be effective. Sincethe conclusion

### ofthe San Ysidro study, the village has assumed ownership ofthe units and is 

### now responsible for operating and maintainingthe 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 compliancetechnologies for at least one 

### IOC. Thetable containsthe same structure asothertables with a list of limitationsthat are contained in the footnotes and operator skill level and raw water quality issuesfor general operation ofthe 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 foulingthe 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 ofwater 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 ranges16.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 Chemicalsrequired during regeneration and pH adjustmentmay be difficult for small systems to handle. May create highly concentrated waste streams. Disposal ofregeneration solution containing high concentrations ofundesired ionsmay 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.

Solidshandling may be an issue. For instance, disposal of arsenic contaminated sludge may be an issue, especially ifdeemed hazardous. 

### ' If all ofthe influent water is treated, then most ofthe 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 ofthe 

### U.S. 

# ' For asbestosremoval, 

### RO has problems with asbestos fibers accumulating on the membrane surfaces. Conventional flushing techniquesmay 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 ofpolymers prior to filtration may be necessary for asbestos removal (EPA 1986b).

O Two-stepprecoating procedure may be necessary for asbestosremoval. A coarse grade is first applied. A second coat conditioned with alum or an anionicpolymer may be necessary (EPA 1986b).
P Continuous addition of a polymer to the raw water may be necessary to improveasbestos 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 ofthe complexities inherent in using lime and soda ash systems. These methodsrequire a high degree ofoperator attention because the calcium carbonate plugs bins, tanks, pumps andpiping (EPA 1992). In operating a sodium hydroxide feed system,employees may have tohandle the strong base. 

### " This approach may cause a btdd-up ofprecipitate in consumers' hot water heaters. "Thistechnology isrecommended primarily for the smallest size category.



### Tanks containing a phosphate-rich solution may experience somebiological growth. Routine cleaning is recommended. When first added, previously corroded material may be released (EPA 1992).
Y Any ofthe first five aeration technologies listed for volatile organic contaminants can be used.
Section 

### 1.3 indicated that EPA would identify affordable compliancetechnologies for those existing regulations where small system variances orvariance technologies are not prohibited by the SDWA. There are statutory prohibitions against small system variances or variance technologies for 

### 13 ofthe 17 

### IOCs. Table 

### 5.2 contains the compliance technologies for the four 

### IOCs where affordability was considered. Affordability only plays a role in removing some ofthe options in the smallest size category. Thetechnology costs are based on treatment of all ofthe 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 ifthe concentration 

### ofthe contaminant is low enough that a portion ofthe 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 forthe remaining thirteen 

### IOCs where affordability was not considered due to statutory prohibitions (EPA 1998b).



# GfTable 

### 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 forthose 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, 1Id, 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 10pg/L. Compliance technology for Selenium 

### VI only. Compliance technology for Selenium 

### IV only.

Following is a listing oftechnologies that EPA did not list as compliance technologies. However, EPA is monitoring the development ofthese technologies and may list them as compliancetechnologies in future updates ofthis guidance.
BioloPical denitrification
For nitrate removal, another appropriate technology may be biological denitrification. In biological denitrification, micro-organismsare fed some form ofcarbon, and use the nitrate as an electron acceptor instead of oxygen. Themicro-organisms reduce the nitrate to nitrogen. Though this technology has been used in wastewater treatment, itsuse in the United States in water treatment is limited. Theprimary reason is that there is concern that since bacteria are being used to treat the water, there is a potential for bacterial contamination ofthe water supply.
Nanofiltration. ultrafiltration and microfiltration
Asbestos:
The MCL for asbestos is 7 million fibedliter and refers only to those fibers longer than 

### 10microns (EPA I991b). For particles ofthat 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~ology can be expected to remove asbestos fibers larger than 

### 10microns. 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 furtherresearch.

### -- Arsenic:
Nanofiltration (NF) membranes have pore sizes that vary from approximately 

### 0.00

### 1 microns to 

### 0.005microns. Because ofthe small pore size, NF can remove both As(II1) and As(V), but as with the othertreatment technologies, NF removesAs(V) more effectively. The small pore size,however makes NFmembranes more prone to foulingthan ultrafiltration or microfiltration membranes. Theapplication ofNF for surface water treatment istypically not accomplished without extensivepretreatment for particle removal andpossible 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 studywith arsenic removal revealed that the removal efficiency dropped significantly during pilot-scale tests where theprocess 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 fluorideremoval and are also applicable for arsenic and selenium removal. Sincethe 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 impliesthat the exchange/adsorption capacity of the activated alumina will be reached in a shortertime, and the spent cartridge will need to be replaced more often. If, after investigation,EPA determinesthat this is not a major issue, POU AA units will be added as compliance technologies in the next update ofthis 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 isa 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 infantshave occurred following ingestion. Households need 

### to be informed about the importance ofmeeting 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 Stateshave resulted from the ingestion ofprivate well water used to make infant formula. Stakeholders suggested that 

### EPA investigate the feasibility ofpublic awareness projects such asusing 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 ofthe brine or concentrate stream may be problematic. In addition, EPA needs to investigate ifthe usage ofa 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. 4998.
American Water Works Association. Water Oualitv and Treatment. A Handbook ofCommunity Water Su~plies. Fourth Edition. McGraw-Hill. 1990. Bartley, C.B., Colucci, P.M. and Stevens, 

### T. “The inorganic chemical characterization ofwater treatment plant residuals”. EPA/600/SR-92; 1 

### 17, 

### 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 ofLake 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 ofthe 1994American 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). TheEauilibrium Arsenic Capacitv of Activated Alumina, PB 84/10 527,NTIS, Springfield.
USEPA. “Technology and Costs for the Removal 

### ofNitrates 

### from Potable Water Supplies”. Prepared 

### by V.J. Ciccone & Associates, Inc. August 1984(EPA 1984a).
USEPA. “Technologies and Costs for the Removal ofMercury 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 

### ofCorrosion at Small Water Utilities” February 1987.
USEPA. “Technologies and Costsfor 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 ofArsenic from Potable Water Supplies”. Prepared by International Consultants, Inc. July 1998(EPA 1998a).
USEPA. “Variance Technology Findings for Contaminants Regulated Before 1996“. EPA 8 15- 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 ofparticular treatment technologiestothe removal ofradionuclides from drinking water depends significantly on the chemical and physical characteristics ofthe contaminants involved and the site specific characteristics ofthe water system, e.g., sourcewater quality and water system size. The considerations that determine feasibility include: high removal efficiency, general geographic availability and applicability (e.g., climate considerations) ofthe technology, cost, service life, and co-treatment compatibility.
Theremoval strategies for radium, gross-alpha emitters, and total beta andphoton emittersexploit the chemistries of the individual contaminants, as with any removal contaminant removal strategy. The chemical properties ofthe contaminant to be removed, e.g., speciation, solubility, tendency to sorb, etc.. have a deciding influence on the ehoice ofthe 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 ofcation versus anion exchange treatment may depend upon the site specific situation. As another relevant example, for coagulatiodfiltrationtreatment processes to be effective for removing elevated gross alpha levels caused by uranium, uranium must sorbto the floc or precipitate before settling or filtration. Highly efficient removal will only occur for those uranium speciesthat sorb significantly under the site specific conditions of the source water as affected bj. the treatment process. For reverse osmosistreatment,the water chemistry ofthe 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 ofthe radioactive decay ofthe uranium-238 (U-238)and thorium-232 (Th-232). 

### Ofthe 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 othernaturally occurring radionuclides are not present in significant amounts in ground water, because oftheir environmental immobility and/or short half-lives. The naturally occurring radionuclides ofthe uranium-238 decay series (uranium-238, radium-226. and radon-222) are responsible for the majority ofradiation 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 ofreleases 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’ comprisesthe majority of “true total alpha activity” in surface waters (i.e., total alpha activity without excludingradon-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 ofthe remainder ofthis discussion’.
When planning removal strategiesfor radionuclides, it is important to understand that different isotopes ofthe same element (e.g., radium-226 versus radium-228) are chemically indistinguishable from the perspective oftreatment (Clifford 1990). In other words, when planning treatment, “radium 

### is radium”.
Chemical Behavior 

### ofRadium
Radium isprimarily a ground water contaminant. Under oxidizing conditions (e.g., surfacewaters), it is very immobile. The sources ofradium to ground water include dissolution 

### ofradium-bearing aquifer solids, “alpha-recoil3”ofradium isdtopesfrom the aquifer solid matrix across the solid/water boundary (Hess et al. 

### 1985), and desorption 

### ofradium from aquifer solids surfaces. Sinceradium itselfisnot very soluble in water and doesnot form strong complexes with common solutesfound in aquifers, the alpha recoil process is important in that it can significantly increase the radium concentration abovethat due to dissolution from the aquifer material. Theradium “liberated” by the alpharecoil 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 ofthe aquifer. For a more detailed discussion ofhow local geology and geochemical processes control the occurrence ofradium 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 solidscontent (Tanner 1964,

### as cited in Zapecza and Szabo 1986,and Michel I991). 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 futureupdated 

### NPDWR for radionuclides. 

# ’ Alpha-recoil refers to the recoil motion ofthe daughter product (the radium isotope, in this case) resulting from the high energy ejection ofthe 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 ofthe alpha particle results in recoil ofthe 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 ofthe radium isotope 

### (Hess et al. 1985). Lmagnesium (all are alkalineearth 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 ofpH 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 ofthis 

### is that cation exchange is usually the most appropriate ion exchangetype.
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 mgLare not unusual. Toput this in perspective, under those conditions, for every radium ion present in solution,there would be 1

### 0”, or one hundred billion, calcium ions competing in the chemical processes2that are exploited in water softening. Fortuitously, radium preferentially sorbsrelative 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 ofradium’s tendency to strongly sorb is that radium tendsto 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 ofthis suspended material. Unfortunately, the averageremoval efficiency from simple filtration is often too low to be very useful (Clifford 1991).
Section 

### 6.2: Evaluation ofTechnologies
Based on the properties ofradium 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 ofthe activity, these sametechnologies would apply. For the removal of 

# ’ 1 pCi/L ofradium roughly correspondsto 1pg/L.

For a discussion of competitive sorption, see Snoeyink 1990,p.788. Radium has the largest atomic weight and hydrated ionic radius ofthe alkaline earth metal cations, which greatly increases its tendency to sorbto ion exchange resins relative to the other alkalineearth cations, including Ca” and Mg”.



# 71gross 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 alsotrue 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 tobe robust enoughto merit a general evaluation.
The best available technolagies (BATs) from the 1991 radionuclides proposed rule (EPA 

### 1991a) were evaluated as small systemscompliancetechnologies. The table below liststhe 

### MCLs and the 1991proposed 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) 15pCi/L RO 4 milliredyear IE, 

### RO

The ion exchange 

### (IS) process and general small systemsconcerns 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/orthe 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. Therinse and backwash liquid waste includes brine, radium, and any other contaminants removed by the process. The contamination ofthe exhausted resin depends upon its loading capacity and the degree ofuse since the last regeneration (EPA 1994). Disposal issues specificto 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 ofpoint-of-entry regenerant wastes are issue that remains to be resolved before this technology will be listed as a small systemscompliancetechnology. Point- ' of-use softeners may be regenerable or disposable. Water systemsmust take care to ensure that

proper radium removal performance isbeing maintained through monitoring and/or maintenance. Ifdrain disposal of regenerant wastes frompoint-of-use softeners

### to sanitary sewers ispossible, 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 exchangeresins are used to remove undesired cations fiom water by exchanging them with protons 

### (H-). sodium ions (Na'), or, in the case 

### of sodiumrestrictions, 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 

### ofchoice for cationic bet3 and photon emitters.
As discussed 

### in thc introduction to this chapter, radium preferentially sorbsrelative to calcium and magnesium. Studich indicate that sodium cation exchange canremove 

### 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 someraw 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 abovethe 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 cuhangeresins 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 exhangersare 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 (rinseand backwash) volume produced by cation exchange for radium removal typicall~r ranges between 

### 2 and 10%ofthe product water volume. Theradium concentration in the liquid waste depends upon the radium influent concentration, the volume of regenerant solution used, and the frequency ofregeneration. An Iowa case study showed liquid waste radium levels between 1IOand 530pCi/L. Another showed an average and peak waste level of 

### 23 and 160pCi/L,respectively. At the latter facility, the exhausted resin accumulated aradium level ofca. 9 pCi/g 

### (EPA 1994)
Anion exchanpe
A few studieshave been conducted to specifically assess the effectiveness of anion exchange for “gross alpha” removal, where either uranium is not the dominant source orthe speciationwasnot specified 

### (EPA 1992). Removals between 85 and 

### 95 percent can be achieved, depending on which alpha emitters are present and onthe 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%. Thisprocess involves inducingprecipitation of calcium carbonate and magnesium hydroxide by increasing the pH 

### of the treated water to ca. 10through 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 10,000persons) because ofthe difficulties resulting from the combination ofvariable source water quality and the complexity ofthe chemistry involved. Changing water quality necessitates frequent monitoring and modification 

### ofthe 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 systemsare 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. TheNational Research Council (1997)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 ifthey have a service contract or a satellite operation that would enable a qualified operator to monitor the treatment process on a regular basis. Sinceradium 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 1,980pCi/L in the wet lime sludge, 

### 6 to 

### 9 pCi/g in the dried sludge, 

### 6to 

### 50 pCi/L in the filter backwash liquid, and ca. 20 to 25 pCi/L in the sludge supernatant 

### (EPA 1994).Reverse Osmosis 

### (R0)
Thereverse osmosisprocess is described in Chapter 

### 3 ofthis document. Reverse osmosis has been shownto be highly effective for removing inorganic contaminants, including heavy metals and radionuclides such asradium and uranium. 

### RO canremove 87to 98% ofradium in drinking water. Similarremovals can be achieved for alphaparticle 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 developmentof membranes capable of operating at much lower pressures (1

### 00 to 

### 200 psi). Low pressure membranesprovide substantial savingsin process electricenergy. Theperformance of an RO system for radionuclide removal-depends upon a number of factors including pH, turbidity, irodmanganese content ofthe raw water, and membranetype. Design ofa pretreatment system 

### is dependent upon the quality and quantity ofthe feed water source and may include one or more ofthe following: pH adjustment, filtration, iron and manganese reduction, or additives for scaleprevention. Existing treatment plants may already provide much ofthe 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 90to >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 ofthe 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 ofthe raw water to be treated will depend upon the removal efficiency ofthe selected RO membrane, the initial concentration of contaminants in the raw water, and the required effluent objective.
The reject water from 

### RO isthe 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 concentrationin the influent and the percent recovery of the operation. For example, ifthe RO unit removes 98%ofradium and rejects 

### 50% ofthe influent water, then the reject water will contain roughly two times the concentration ofthe influent water. Studiesreport ranges ofca. 

### 8 to 40 pCi/L ofradium 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 systemstreatment option for inorganic contaminants removal (NRC 1997),including radium, since it isreliable, effective, and simpleto use onthe 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 tothe sink drain for reject water disposal. The discharge line requires an air gapto prevent a cross-connectionbetween wastewater and drinking water.
Since general 

### POU concernsare described above, this section will focus on reject water disposal concerns. One

### ofthe primary advantages of

### POU 

### RO is that reject water waste disposal is straightfonvard if drain disposal to a sanitary sewer 

### is possible. Althoughthe total mass or concentration ofradionuclide contaminants discharged from the house would not significantly change when 

### ROtreatment isinstalled, the reject water does contain higher radionuclides concentrationsthan 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 inthe untreated water. Sincethe drain water from a singletap 

### is usually a small part ofthe drain water budget of the entire household, this dilution should occur very quickly. The table below showsthe relationship between the

### YO increase 

### in radium concentration for the total household drainage versus the ROrecovery percentage:



# I Percent Increase in Radium Concentration in Household Drainage versus RO Rejection Percentage 

# I 

# 1 YO Recovery' 

# 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 inthe total house drainage. !.e., for a recovery of 50% and an untreatedwater (influent) radium concentration of 10 pCi/L, the total house drainage would have an average concentration of 10.5pCilL 0.6

The table assumes that drinking and cooking water comprises 

### 5% ofthe total household water 

### (EPA 1991)and that the rest ofthe water is returned to the drain. As the table shows, ifthe drain water is discharged to a sanitary sewer,the concentration ofradionuclides reaching the waste water treatment plant should not be significantly affected by the addition of POU 

### RO. Clifford ( 1991a)reports a 

### 15%recovery for spiral wound POU RO astypical. At this recovery, the reject water is concentrated by a factor of about 1.18relative 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 

# 7bl

-

I * Stakeholdersdiscussed the possibility ofusing 

### 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 centralizedtreatment assumptions and may not coverPOU 

### RO scenarios. This issue deserves attention in the future. Technolopies forRadionuclide Removal Not ProDosed as BAT in 1991
Greensand Filtration for Radium Removal
Greensand filtration technology consistsof a conventional filter box with the traditional filtration medium replaced by manganese greensand. Manganese greensand has enhanced sorptive abilitiesthat 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% 

### ofradium 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. 65to 170pCiL Dry weight concentrations 

### ofradium in the greensand medium have been found to vary from ca. 30 to 46 pCi/g at one plant and from 75 to 250pCi/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 isplanned (Clifford 1990a). Pilot studies conducted in Illinois consisted of a pre-formed MnOz(HMO) dosage of 2.0 mgL,followed by a minimum often seconds of mixing and post-mixing diatomaceous earth filtration or multi-media filtration to remove the suspended MnOz(which containsthe sorbed radium). Greater than 96% removals were consistently achieved over the five day run period (Clifford 1990a). Valentine et al. (1992) reported averageremovals of 83%, 79%, and 71%for 

### HMO dosages of 1

### .O, 

### 0.5, and 0.2 mg/L (asMn). 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 asbarium chloride to water contaminated with radium and sulfatewill 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% 

### ofradium isremoved by thisprocess. A fullscale drinking water treatment plant 

### in South Dakota currently uses this processto treat a radium influent level 

### of 16pCi/L down to < 1 pCiL
Radium containing wastes generated by thsprocess includethe barium sulfateprecipitate sludge,filterbackwash, 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.. acnIlc fikrsor resins impregnated with manganese dioxide) and nonsodium cation exchangers (eg
. h! drogen ion and calcium ion exchangers) for radium removal. 

### POE 

### IX and RO are not currcntl! Ii~d as compliance technologies because ofunresolved issues regarding waste disposal. post-trcatnicnt disinfection and corrosion control, and costs, but are being further considered as smal1 \tcms compliance technologies.
Radiation Hazards AssociatrJ H ith 

### 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 

### ofradionuclide. \\ ithin the treatment unit 

### or in wastestreams.
Waste Generation and Disno\aI (;uidelines #Waste Peneration
In the I991 proposed radionuclidesrule (EPA 1991a), EPA referenced a 1990EPA report entitled “Suggested Guidelinesfor the Disposal ofNaturally Occurring Radionuclides Generated by Drinking Water Treatment Plants” (EPA 1990). In 1992,the ScienceAdvisory Board (SAB) reviewed the 1990guidance and offered several recommendations.’ Among the most important SABrecommendations 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 spreadsheetprogram 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 andpreengineering stages where managers will need information on the types ofwaste that may be generated at new facilities. The spreadsheetprogram was developed by EPA in August 1993and 

### 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‘ssccond rccommendation. the occupational guidance has been revised by the Office of Radiclticm 3nd Indoor Air. It was determined that the dosesthat 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’ dosesto well \vithin thc ir.\cls recommended for the general public 

### (100 mredyr). Consequently. the guidance rectmnic*nds

### 100mrem/yr asthe 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 ofusing activated carbon for removal ofradon. which is currently unregulated. Sincethis 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

‘Letterfrom Dr. 

### R.C. Loehr and Dr. O.F.Nygaard. Science Advisory Board, to 

### W.K. Reilly, EPA. September 30, 1992.new section on suggestedwastestream samplingprocedures.
The report was updated in 1994with the abovementioned revisions and is entitled “Suggested Guidelines for Disposal ofDrinking Water Treatment Wastes Containing Radioactivity” (EPA 1994). The updated guidelines are summarized in the followingtwo figures and table; for details, please refer to the guidelines. Summaries

### ofthe 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 summarizesestimated waste volumes, radioactivity levels andtypes of waste generated by several ofthe above mentioned drinking water treatment processes. These estimates arebased on standard engineeringassumptions and an assumed average daily water production of 

### 1

### .Omillion gallons per day 

### (MGD).
Characteristics

### of Selected Water TreatmentWastes (Computed Levels)

Treatment Waste Characteristics: Method Finished Vol. and Radioactivity Conc. 

# L

(PCW

~~ ~ ~~ ~ Coagulation/ 50/10 U Sludge volume: 10 kgpd Filtration (Uranium) U sludge:4,000 pCi/g 

# t

Ra Sludgevolume: 22

25112.5 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: 130kgpd Osmosis (U) U wastes: 320 pCiiL Types ofwaste generated

~ ~ ~ Iron or alum sludges from the contact and settlingbasins and from the filter backwash. Supernatant from this sludge is a liquid waste. Additional liquid waste is generated when the sludge is concentrated prior todisposal. Settling tank sludge, which is precipitated during the softeningprocess. 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 streamswhich are continuously generated during the treatment process.

I Figure 1 is a flowchart summarizingthe guidelines for disposal ofradioactive liquids. The Clean Water Act requires that dischargers ofpollutants 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 ofradionuclides in the surfacewater or sedimentsto within limits setby the regulator. Pretreatment regulations prohibit discharge into sanitary sewersthat would cause a municipal Iwastewater treatment plant to violate 

### a 

### NPDES permit. The 

### U.S. Nuclear Regulatory Commission 

### (NRC) limits the discharge ofwastes 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. Stateregulations 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 ofthe 

### USEPA before deciding to dispose 

### ofwastes containing radionuclides into an injection well.



# .

# Figure 

# 1. 

# Disposal 

# ofhquid 

# wmtes

WaterTreatment Liquid

# Wastes 

# pi

Waters 

# Ra22840 

# u<300

Injection Wells Sanitary

48-­ 

# 8'cFigure 

### 2 is a flowchart summarizing the guidelines for radioactive solids/sludges. Wastes containing lessthan 

### 3 pCi/g (dry) 

### ofradium and less than 

### 50 ug/g (dry)ofuranium 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) ofradium should be disposed ofwith a physical barrier that would protect against radon release and isolate the wastes, and provided with institutional controls designed to avoid inappropriate uses 

### ofthe disposal site. The disposal method for solids/sludges containing 

### 50to 

### 2,000 pCi/g (dry) 

### ofradium should be determined 

### on a caseby casebasis. Recovery ofthe uranium resource may be considered for solidscontaining 

### 50to 

### 500 ug/g (dry) of uranium. Wastes containing more than 

### 2000 pCi/g (dry) ofradium or more than 

### 500ug/g (dry) ofuranium should be disposed of only aspermitted 

### by State regulations.

# Figure 2. Disposal 

# of 

# Solid Wastes (Municipal Physical Barrier

3 C= 

# Ra <

# 50 

# u <

# 50 

# v 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

RecoverySection 6.3: Small Systems Compliance Technologies List
Based on the evaluation ofthe technologies described in Section 6.2, the following table lists the Small Systems Compliance Technologiesfor 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 

### Fi1tration 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

Surfacewaters 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 WaterfiomEvery Tap: Zmproving Water 

### Service to Sniull Communities. National Academy Press. Washington, D.C. 1997. 

# !. Limitations Footnotes to Table: Technologiesfor Radionuclides:
The regeneration solution containshigh concentrations ofthe 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 ensureproper performance (see Section 1.4).Reject water disposal options should be carefully considered before choosing this technology. Seeother RO limitations described in Chapter 

### 3 and Section 6.2. The combination of variable source water quality and the complexity ofthe chemistry involved in lime softening may make this technology too complexfor small surface water systems.

e Removal efficienciescan vary depending on water quality.

Thistechnology may be very limited in application to small systems. Sincethe 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 Thistechnology is most applicable to small systemsthat already have filtration in place. Chapter 1 indicated that EPA would identify affordable compliancetechnologiesfor 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 affordability cannot be considered inhtingthese technologies. Thefollowingtable contains the compliance technologies the three radionuclides. The statutory prohibitions on variance technologies and small system variances are discussed in detail in Chapter 1 ofthis document and Section 

### I\’ of the “Small Systems ComplianceTechnology Lists for Existing National Primary Drinking Water Regulations” (EPA 1998b).

Table 6.2: Compliance Technologies by System Size Category forRadionuclide 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 1,2,3,4Section 

### 6.4: Emerging Technologies



# “

~

, - 

# I* POE ion exchange and POE reverse osmosishave 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 futureupdates, 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 ofCommunir\ \\‘ater SuDDlies. 

### 4 ed. 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 Serviceto 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. cSorg,

### T.J. “Removal ofUranium from Drinking Water by ConventionalTreatmentMethods”. In Radon. Radium. and Uranium in Drinkinp Water, Cothern and Rebers, eds., LewisPublishers, Chelsea, Michigan, 1990.
USEPA. “National Workshop onRadioactivity in DrinkingWater: CommitteeIssue Papers”. Committee on Treatment,WasteManagement,and Cost. Reid, G.W., Chairman. May 1983.
USEPA. “Suggested Guidelinesforthe Disposal ofDrinking Water TreatmentWastes ContainingNaturally-OccurringRadionuclides”, Office ofDrinkingWater. July 1990.
USEPA. “NationalPrimary Drinking Water Regulations;Radionuclides;ProposedRule”. Federal Register. Vol. 56, No. 138,

### p. 33050. July 

### 18, 1991. (EPA 1991a).
USEPA. “Manual ofIndividual and Non-Public Water Supply Systems”. Office ofWater. EPA 570/9-91-004. May 1991. (EPA 1991b). s USEPA. “Technologiesand Costsfor the Removal ofRadionuclidesfrom Potable Water Supplies”. Prepared by Malcolm Pirnie, Inc. July 1992.
USEPA. “Suggested GuidelinesforDisposal ofDrinkingWater Treatment Wastes Containing Radioactivity”. OGWDW. Draft, June 1994.
USEPA. “Technology TransferHandbook: Management of Water Treatment Plant Residuals” Office ofResearch and Development. EPA/625/R-95/008. April 1996.
USEPA. “Addendumto: Technologiesand Costsfor the Removal 

### ofRadionuclidesfrom Potable Water Supplies

### - Draft Report”. Prepared by International Consultants, Inc. Draft, June 1998. (EPA 1998a).
USEPA. “Announcement of Small SystemsComplianceTechnologyLists for Existing National Primary Drinking Water Regulations and Findings ConcerningVariance Technologies”. Federal Register. Vol. 63,No. 151,p. 42032. August 6, 1998. (EPA 1998b).
USEPA. “Cost Evaluationof Small SystemCompliance 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 ManganeseDioxides”. 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 Paper2325. p. 50-57. 1986.7. SMALL SYSTEMS COMPLIANCETECHNOLOGIES 

### 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 orvaporize easily into air at room temperature. Volatile organic compounds are usually used as solvents,degreasers, and fumigants. Table 

### 2.1 1lists the National Primary Drinking Water Standards for, regulated VOCs.
VOCstypically are found in greater amounts in groundwater suppliesthan surface water because exposure to air helpsthem dissipate from surface supplies. In groundwater supplies, the compounds are very mobile and percolate into wells and aquifers. The compounds do not degradereadily in the groundwater and, as

### knowor suspected carcinogens, are a potentially seriousthreat to drinking water safety. 

### -_
The technologies considered for the small systems compliance list are commonly used in the drinking water industry. The BATSfor removal ofVOCs 

### from drinking water are granular activated carbon and packed tower aeration. Thetechnologieslisted 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 includepowdered activated carbon, gaspermeable 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 ofthe volatile nature of

### VOCs, the indooruse 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 ofthe aeration units. Also, there isthe 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 

### ofTechnologies
Packed TowerAeration
Packed tower aeration has been proven to effectively remove several VOCs from drinking water. Packed tower aeration is considered a BAT for VOCsremoval. Theremoval efficiency for VOCs isprimarily 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 ofpacking materials determinethe available area for mass transfer. Smaller materials may provide greater areas of mass transfer, however, an increased pressure drop may occur ifthe materials aretoo small.
Field tests performed in Brewster. 

### NY, Wausau, 

### WI, and Baldwin Park, CAresulted in >96% removal efficiencies for VOCs such astetrachloroethylene, trichloroethylene, cisdichloroethylene, and toluene. The influent concentrations were asgreat 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).
Someofthe concerns with PTA units are that repressurization equipment and blowers drawlarge amounts of electricity. therefore. electrical costs are high. Ifthe 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 ensureno microbial growth.
Diffused Aeration
Similarto 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 (1984) showed that diffused aerators can efficiently treat VOCs with influent concentrationsranging 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 higherfor VOCs with the higher Henry's Law Coefficients.
Diffused aeration units may not be asefficient as other aeration methods because it does not provide for convective movement ofthe water thus limiting air-water contact. It is generally used to adapt existing plant equipment such as storage tanks or basins. Theremoval efficiency ofthese systems dependsupon the gas to liquid mass transfer rate. Thediffused aerator has less interfacial area for mass transfer than the PTA; a longer contact time may be needed to achieve sufficient removal ofthe VOCs. On the other hand, increased basin depth, contactbasin geometry, and turbines 

### to reduce the air bubble size and increase bubble holdup can improve gas transfer, thus improving the efficiency 

### ofthe system.
With diffused aerators, increased energy costsmay be incurred duetopost-treatment repressurization. .Also,post-treatment disinfection may have to be used to ensureno 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 dependsupon the air-to-waterratio. These units have the same limitations as the diffused aerator.
Multinle TravAeration Multiple tray aeration is considered a conventional technology for the removal ofVOCs from drinking water (NRC 1997). Xlultiplc tray aerators consist of a seriesoftrays with slats, perforations, or wire mesh bottoms o\wuhich 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 ofVOCs from drinking water (Robeck and Love 198;. 1less et a1 

### 1981). In studies performed in Smyma, Delaware reported removal efficiencies ranging from 50 to 90% oftrichloroethylene and other VOCs. In Camden, New Jersey (1979)conducted studies to determine the efficiency ofthe 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.
Theperformance oftray 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 ofthe forced draft may increase the cost ofthe unit. Post-treatment disinfection may be necessary because slime and algae growth can be a problem. Chemicals such ascopper sulfate or chlorine may have to be used to control the growth.
Shallow TravAeration (STA)
STAs involve the use of shallowtrays, and are more efficient to multiple tray aerators. STAsincrease the available area 

### ofmass transfer;thereby increasing the removal efficiency of most VOCs. However, because ofthe high air-to-water ratio (100-900 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 dropletsproduced 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) demonstratedthat > 99%ofVOCs wereremoved from an influent total VOC concentration between 

### 100-200pg/l. Theprimary 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 efficientremoval 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 asenergy efficient asother 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 ofVOCs 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 systembetween 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 sufficientto 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 IGranularActivated Carbon
For the purposes ofdetermining best availabletechnologies (BATs) for removing SOCsfrom drinking water, the SafeDrinking Water Act 

### (0 1412.b.4.D)explicitly statesthat any BAT listed by EPA must be at least aseffective as granular activated carbon (GAC). The various BATs listed for the Phase 

### I1 and V SOCsare GAC, packed tower aeration (PTA), and, in the case of gylphosate, oxidation by chlorinationor ozonation (EPA, 1991a, 1991b, and 1992b). However, for the purposes ofdeterminingthe list ofcompliancetechnologiesfor small systems of a given size category,the Safe Drinking Water Act (§ 1412.b.4.E) statesthat 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 technologiesdo 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 ofVOCs. It ispacked 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 controlthan ispossible forpowdered activated carbon (Snoeyink 1990). In many cases GAC has been used to treat several VOCs to the maximum contaminantlevelswith influent concentrationsranging 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 oftime or gallons of water treated. The amount of water treated depends onthe influent contaminantconcentration, the amount of carbon in the treatment unit, and the time the contaminant is in contact with the carbon. The removal efficiency ofthe carbon system will deteriorate with use, and eventually breakthrough will occur. Section 7.3: Small System Compliance Technologies List
Table 7.1 containsthe technologies that have been identified ascompliancetechnologies for at least one VOC. The table containsthe same structure asother tables with a list of limitations that are contained inthe footnotes and operator skill level and raw water quality issues.
Table 7.1: Technologies for 

### 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 waters3. 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

LimitationsFootnotesto the Technology Tables for 

### VOCs

a Pretreatment for the removal ofmicroorganisms, 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 ofthe water thus limiting air-water contact. It is generally used only to adapt existingplant equipment. This units are highly efficient, however the efficiency dependsupon 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 ofthe contacting system.
g For use only when a low removal levels are needed to reach an MCL because these systemsmay not be as energy efficient as other aeration methods because ofthe contacting system. The units often require large basins, long residence times, and high energy inputswhich may increase costs. Seethe 

### SOCs compliance technology table for limitation regarding these technologies.

Chapter 1 indicated that EPA would identify affordable compliance technologies for those existingregulations where small system variances or variance technologies are not prohibited by the SDWA. There are statutory prohibitions against small system variances orvariancetechnologiesfor 

### 2 ofthe 2

### I VOCs. Table 

### 7.2 containsthe compliancetechnologies for the 

### 19VOCs where affordabilitywas considered. Affordabilityonly plays a role in removing options in the smallest size category. The technology costs arebased on treatment of all 

### ofthe water. The technologiesthat did not meet the affordabilitycriteria in the smallest size category are also identifiedin the next column called “other compliancetechnologies.” These technologiesmay be affordable ifthe concentration

### ofthe contaminantis low enough that a portion ofthe influent stream can be treated and blended with 

### an untreatedportion to still meet the 

### MCL. This blending would reduce both the capital.and operatingand maintenance costs of the process. Systems and States should considerthese options under those circumstances. Table 

### 7.3 containsthe compliance technologies for the remainingtwo VOCs where affordabilitywas not considereddue to statutoryprohibitions 

### (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-

Dichloroethane1,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 orto a mixing basin. In order to treat VOCs effectively, PAC must contact all ofthe 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 ofwater treatment is sufficient for contaminant adsorption onto PAC. However, the contact time hasto be determined prior to the design ofthe process. The dose of PAC added to the system has to be adaptedto deal with varying source water quality.
The removal efficiencies ofVOCs 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. Ifthese facilities are inplace, PAC is simple to employ on a small scale. PAC is considered 

### an emerging technology because long-term performance for treatment ofVOCs has not been evaluated. Gas-Permeable Membrane Aeration Gas-permeable membrane aeration is an emerging technology (NRC 

### 1997). In gas permeable membrane systems, water flowsthrough the interior ofhollow 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 emergingtechnology. The majority of advanced oxidation research as focused on treatment of chlorinated organicspresent in groundwater. Advanced oxidationprocesses 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 StudiesInvolving Removal of Organic Chemical Compounds from Groundwater”. Presented at the Preconference Seminar Concerning Organic Chemical Contaminantsin Ground Water at the 1981Annual Conference ofthe American Water Works Association. St. Louis, Missouri. June 7-1 1, 1981.
National Research Council (NRC). Safe Water From Every Tap: ImDrovingWater 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 ofVolatile Organic ComDoundsin Water Supdies. Lewis Publishers. pp. 363-391. 1990. Robeck, 

### G.G. and Love, O.T. “Removal ofVolatile Organic Contaminants from Ground Water”. Presented at the International Conference on Ground Water Contamination from Organo-Chlorine Compounds ofIndustrial 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 ofthe American Water Works Association. 8

### l(4): 162-167. 1989. Snoeyink,V. 

### L. “Adsorption oforganic compounds”. Chapter 

### 13in 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 ContaminantsRegulated Before 1996”. EPA 8 15- R-98-003. Office of Water. September 1998.
Wood. P. R. Removal of Volatile Organic ComDoundsfrom Water bv Sprav Aeration. Paper presented at Seminar of Small Water SystemsTechnology. 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 diversegroupof chemicals in terms ofproperties, although most ofthem areused aspesticides and find their way into drinking water through this common use. They vary widely with regard to chemical structure, make-up, and charge, which causesthem to exhibit a range of environmental behaviors. For the samereasons, the removal of these compounds in drinking water treatment processes also varies. For example, Miltner et al. (1989)demonstratedthat 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 

### ofthe 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 determinethe behavior of 

### SOCs in the environment and duringtreatment processes include volatility (tendency to evaporate), water solubility, and resistance to chemical degradation. Volatile SOCscan enter the atmosphere and. if chemically persistent, travel great distances before being deposited. Modes of atmospheric deposition ofpollutants include dry-fall, or deposition ofthe pollutant directly from the air or when attached to settling dust, etc. and wetfall, or deposition ofthe pollutant through rainfall, snow, or other precipitation (Schnoor 1996). Through atmospheric deposition. contaminants can reach surface waters and soilsthat are otherwise pristine. For examplc. uatcrs and soilsthat donot receive agricultural run-off can become contaminated with pcsticidcs bccause ofatmospheric 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). Ifthe 

### SOC isrelatively 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 itstendency to sorbto GAC (Snoeyink 1990, Schwarzenbach et al. 1993).
Ten technologies for the removal ofthe 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 ofdetermining best available technologies (BATs)for removing SOCsfrom drinking water, the Safe Drinking Water Act 

## (51412.b.4.D)explicitly statesthat 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 1991

### a, 1991b and 1992a). However, .1for the purposes 

### ofdetermining the list of compliance technologies for small systems

### of a given size category, the Safe Drinking Water Act ( (51412.b.4.E)statesthat any listed technology must be affordable and able to achieve compliancewith the maximum contaminant level. 

### To emphasizethe point, the listed small systems compliance technologies donot have to be as effective 

### as GAC in controlling SOCs.
Section 

### 8.2: Evaluation 

### ofTechnologies
Granular activated carbon (GAC) and powdered activated carbon 

### (PAC)
The activated carbon processes are described in Chapter 

### 3 ofthis document 

### and in detail in terms of SOCsremoval in the "technologies and costs" regulatory support documents for the Phase 

### I1 and Phase V final rules (USEPA 1990and 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 ofthe 

### SQCs. However, both technologies exhibit a wide rangc 

### ofremoval 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*Jictfull-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 1990and 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 toremove taste and odor compounds and other organic contaminants in a non-regulatory manner and is a potentially cost-effective way for small systemsto 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 TowerAeration (PTA)
Packed tower aeration (PTA) 

### is BAT for several ofthe 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.
OtherAeration Technoloyies Chapters

### 3 and 7 describe other aeration technologiesrelevant to the removal ofthe volatile Phase I1 and V 

### SOCs.
Oxidation
Oxidationby chlorination or ozonation 

### is BAT for glyphosate. Other oxidationprocesses are potentially applicable, but sufficient published data is not available. Issues and caveats regarding chlorination and ozonationuse by small drinking water systems are described elsewhere (EPA 1997,EPA 1998b).
Section 

### 8.3: Small Systems Compliance Technologies List
Based on the evaluation ofthe 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 Surfacewater may require Activated Carbon pre-filtration (GAC)

~ 

### 2. Point ofUse 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 water5. 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 WaterpornEvery Tap: Improving Water Service toSmall 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 ensureproper performance. Most applicableto 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 ofmicroorganisms, iron, manganese, and excessive particulate matter may be needed. Post-treatment disinfection may halie to be used.

e May not be asefficient 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 14ofthe 32 SOCs. The following table containsthe compliance technologies for the 18 SOCswhere affordability was considered. Affordability only plays a role in removing options in the smallest size category. Thetechnology costs are based on treatment 

### '. Iof all ofthe water. The technologiesthat did not meet the affordabilitycriteria in the smallest size category are also identified in the next column called “other compliancetechnologies.” Thesetechnologies may be affordable ifthe concentration ofthe contaminantis low enough that a portion 

### ofthe influent stream can be treated and blended with an untreatedportion to still meet the MCL. This blending would reduce both the capital and operating and maintenance costs of the process. Systemsand States shouldconsider these options under those circumstances. The subsequenttable contains the compliancetechnologies for the remaining fourteen SOCs where affordabilitywas not considered due to statutoryprohibitions. The statutoryprohibitions on variancetechnologies and small system variances are discussedin detail in the Variance TechnologiesFindings Document (EPA 1998c).

Table 

### 8.2: Compliance Technologies by System Size Categoryfor those SOC NPDWRs

Con aminant

Alachlor Atrazine Carbofuran Dibromochloropropane


### 2,4-D Lindane

~ ~ Methoxychlor Pentachlorophenol Dalapon Di(2-ethylhexy l) adipate



# ’ where Affordabilityis 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 assumesthat the small system already has the appropriatetreatment train in place for mixing, contact. and filtration.Contaminant

Contaminant

Chlordane Ethylene Dibromide Compliance Technologiesfor 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 showpromise as compliancetechnologies 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 

### SOCsremoval via membranes are limited and because there are so many variables that affect membrane removal efficienciesfor SOCs, EPA will evaluate them further before listing any membrane technologies as small systems compliancetechnologies.

### POE GAC
As described above, POE GAC showspromise 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. 31ded. 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 ofthe 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;itionalWater 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 ofthe Series, Pesticides in the Hvdrologic System. 

### USGS. Ann Arbor Press. Inc 1(w'
National Research Council >;it? \\ ,itc'r From Every Tap: Improving Water Serviceto 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"ded. Karlsruhe, FRG. 1988.

### -- Snoeyink,V. 

### L. “Adsorption of Organic Compounds”. AWWA, Water Oualitv and Treatment: A Handbook 

### ofCommunitv Water Supplies. 4‘h ed.. Pontius, F., ed. McGraw-Hill, Inc. New York. 1990, Speth,T.F. “Removal of VOCs from Drinking Water by Adsorption”. Significanceand Treatment 

### ofVolatile Organic ComDoundsin 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 SafeDrinking 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 ofDrinking 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. 31776. July 17, 1992. (EPA 1992a)
USEPA. “Technologies and Costsfor the Removal ofPhase 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 TreatmentRule”. 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 ContaminantsRegulated before 1996”. EPA 

### 8 15- R-98-003. Washington, D.C.: EPA Officeof Water. September 1998. (EPA 1998~). Weber, W. J., Jr. Phvsicochemical Processes for Water Ouality Control. Wiley

- Interscience. New York. 1972. IWiesner, 

### M. 

### R.. Hackney, J., Sethi, 

### S..Jacaneglo, 

### G., and Laine, 

### J. 

### M. “Cost Estimates for Membrane Filtration and Conventional Treatment”. Journal ofthe American Water Works Association. 

### 86(12). pp. 

### 33 

### - 41. 1994.

h

### APPENDIX A


### RELEVANTPARTS OF SECTIONS 141

### 2 

### OF THE REVISED (1996) 

### SDWA

### SEC. 105.TREATMENTTECHNOLOGIES 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 oftechnologies 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 

### 10,000or fewer but more than 3,300; “(11) apopulation 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 ormodular 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 ensureproper 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. TheAdministrator 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 ortreatment technique requirement for a microbial contaminant (or 

### an indicator of a microbial contaminant). IftheAmerican National Standards Institute [[Page 1 10 STAT. 162611
has issued product standardsapplicable to a specific type ofpoint-of-entry or point-of-use treatment unit, individual units ofthat type shall not be accepted for compliance with a 

# .maximum contaminant level ortreatment 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 ofthe source water to be treated. "(iii) List oftechnologies 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). (I1 j, and (111) of clause 

### (ii) for each national primary drinking water regulation promulgated prior to the date of enactment 

### ofthis paragraph. "(iv) Additional technologies.--The Administrator ma!. at any time after a national primary drinking \rater regulation has been promulgated. supplement the list oftechnologies describing addititd ornew or innovative treatment technolog ICSthat meet the requirements ofthis paragraph torcategories of small public water system3 Jc-kirikcfin 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 

### ofthis 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