Water Treatment Technology
Feasibility Support Document
f°r Chemical Contaminants; In
Support of EPA Six-Year
Review of National Primary
Drinking Water Regulations
-------
Office of Water
Office of Ground Water and Drinking Water (4607M)
EPA815-R-03-004
www. e pa. g ov/safewate r
June 2003
Printed on Recycled Paper
-------
EPA815-R-03-004
Water Treatment Technology Feasibility Support Document
for Chemical Contaminants;
In Support of EPA Six-Year Review of
National Primary Drinking Water Regulations
June 2003
United States Environmental Protection Agency
Office of Water
Office of Ground Water and Drinking Water
Standards and Risk Management Division
Targeting and Analysis Branch
1200 Pennsylvania Avenue, NW (4607M)
Washington, DC 20460
Treatment Feasibility Review 1 June 2003
-------
Treatment Feasibility Review 11 June 2003
-------
TABLE OF CONTENTS
ACRONYMS v
I. Introduction 1
II. Treatment Reviews for MCL-type Standards for Which Health Risk Assessments Were
Completed or Anticipated 4
A. Beryllium 5
B. Chromium (Total) 5
1. Treatment technology 5
2. Additional information 6
3. Potential in-place treatment modifications 7
4. Potential chromium treatment research 8
C. Fluoride 8
1. Treatment technology 8
2. Potential in-place treatment modifications 10
3. Potential fluoride treatment research 11
D. Oxamyl 11
E. Picloram 11
III. Treatment Review for Chemical Contaminants Regulated by Treatment Technique (TT)
Requirements 12
A. Acrylamide and Epichlorohydrin 12
B. Lead and Copper Rule 12
IV. Chemical Contaminants With MCLs Limited by Analytical Feasibility 14
A. Volatile Organic Contaminants 14
1. Benzene, Carbon Tetrachloride, 1, 2-dichloroethane, and
Trichloroethylene 14
2. 1.2-Dibromo-3-chloropropane (DBCP) 15
3. Dichloromethane (Methylene Chloride) 15
4. 1.2-Dichloropropane 15
5. Tetrachloroethylene ("Perc") 16
B. Other Contaminants 16
1. Chlordane 16
2. Heptachlor 16
3. Heptachlor Epoxide 17
4. Hexachlorobenzene 17
5. Thallium 17
6. Toxaphene 18
7. 1.1,2-Trichloroethane 18
V. Contaminant for Which BAT Is Not Clear or Is Incorrectly Specified 18
VI. Contaminant for Which Public Comments on EPA's Review Provided New Information
19
Treatment Feasibility Review 111 June 2003
-------
TABLE OF CONTENTS, continued...
VII. Contaminants for Which Additional Health Assessments Were Completed in 2002 or
Were Anticipated in 2003 20
A. 1,1-Dichloroethylene 20
B. Lindane 20
C. Toluene 21
D. Xylenes 21
VIII. Summary of Potential Research Needs Related to Treatment Feasibility 22
IX. References 23
LIST OF TABLES
Table 1. Chemical NPDWRs Included in This Treatment Feasibility Document 3
Table 2a. Ground Water Systems: Percentage of CWSs with Various Types of Treatment .... 8
Table 2b. Surface Water Systems: Percentage of CWSs with Various Types of Treatment .... 8
Treatment Feasibility Review IV June 2003
-------
ACRONYMS
BAT
BTGA
CFR
CWS
CWSS
EPA
FR
GAC
GFH
LCR
MCL
MCLG
mg/L
NPDWR
PAC
POE
POU
PQL
PTA
SDWA
SnCl2
TCLP
TCR
TT
USEPA
VOC
Micrograms per liter
Best available technology
Best technology generally available
Code of Federal Regulations
Community water system
Community Water System Survey
United States Environmental Protection Agency
Federal Register
Granular activate carbon
Granular ferric hydroxide
Lead and Copper Rule
Maximum contaminant level
Maximum contaminant level goal
Milligrams per liter
National Primary Drinking Water Regulation
Powdered activated carbon
Point-of-entry
Point-of-use
Practical quantitation level
Packed tower aeration
Safe Drinking Water Act
Stannous chloride
Toxicity characteristic leaching procedure
Total Coliform Rule
Treatment technique
United States Environmental Protection Agency
Volatile organic chemical
Treatment Feasibility Review
June 2003
-------
Treatment Feasibility Review VI June 2003
-------
I. Introduction
This water treatment technology feasibility support document summarizes available
treatment feasibility information in support of the United States Environmental Protection
Agency (EPA) review of National Primary Drinking Water Regulations (NPDWRs). A review
of NPDWRs is required at least once every six years under section 1412(b)(9) of the Federal
Safe Drinking Water Act (SOWA), as amended in 1996. The 1996 to 2002 Six-Year Review of
NPDWRs addresses 68 regulated chemical contaminants (i.e., most of the chemical contaminants
regulated prior to 1996), in addition to the Total Coliform Rule (TCR). This document supports
EPA's review decisions on the chemical contaminants, but it does not address the TCR review
decision, which is documented separately.
EPA sets non-enforceable maximum contaminant level goals (MCLGs), based on health
effects information and related risk analyses. EPA enforceable standards include maximum
contaminant levels (MCLs) and treatment techniques (TTs) which are dependent upon EPA-
documented treatment feasibility assessments and other considerations.
EPA developed a systematic approach or protocol for the review of these NPDWRs
(USEPA, 2003a). Several technical analyses were completed by EPA in the 1996 to 2002
review of chemical NPDWRs. In addition to water treatment technologies, the analyses
addressed human health effects of the subject contaminants, analytical methods, chemical
occurrence, and other aspects related to the regulations. These analyses were conducted
individually and are documented separately. They are referenced in this report, as appropriate.
Results of the above-cited analyses were used by EPA to make a preliminary
determination as to which NPDWRs may be appropriate for revision (i.e., the analyses identified
possible or potential candidates for revision based upon the review of new scientific data). On
April 17, 2002, EPA published its preliminary findings in the Federal Register (67 FR 19030
(USEPA, 2002a)). That was followed by a public comment period, during which EPA received
comments on its review of NPDWRs, including the review of treatment feasibility. EPA
responded to these comments in the Public Comment and Response Summary for the Six-Year
Review of National Primary Drinking Water Regulations (USEPA, 2003d), and in a subsequent
Federal Register notice.
This document contains similar material as the earlier draft report that was developed in
support of the Agency's preliminary findings (USEPA, 2002b). However, it has been augmented
with information presented and discussed in public comments on EPA's April Federal Register
notice. With this and other new information that became available since April 2002, discussions
were added in two latter sections of the document which were not included in the earlier draft
technology report. In addition, section VIII of this report incorporates a summary of potential
treatment-related research areas. The potential water treatment research areas stemmed from
EPA's review of available information, including public comments. This list will be used to
inform and guide EPA's internal research strategy and may be further discussed with external
parties, (i.e., EPA stakeholders), as appropriate. Results of appropriate treatment research,
whether initiated by the Agency or by others, would be used in support of future reviews of
NPDWRs.
Treatment Feasibility Review 1 June 2003
-------
In terms of the process EPA has followed in determining which standards require a
technology feasibility review, the Agency focused on individual NPDWRs if either of the
following conditions applied:
A health effects technical review suggested a potential change to the MCLG; or,
A health effects assessment was not in process (or scheduled) for the contaminant
and one of the following conditions applied: (1) the analytical feasibility
assessment suggests a potential revision to the regulated level; (2) the NPDWR is
a TT-type rule.
In addition, EPA reviewed treatment feasibility information for NPDWRs for which the
best available technology (BAT) or TT requirements were not clear or were incorrectly specified
(one such NPDWR was identified) and information that EPA received during the comment
period following publication of the April 17, 2002, Federal Register notice (67 FR 19030
(USEPA, 2002a)). Some new treatment information was supplied to EPA for the contaminant
antimony as part of the public comments on that notice. Table 1, below, lists the chemical
NPDWRs discussed in this report. This tabulation has been updated since the draft report was
released, incorporating NPDWRs for which new EPA health assessments were anticipated in
2002 or 2003.
Treatment Feasibility Review 2 June 2003
-------
Table 1. Chemical NPDWRs Included in This Treatment Feasibility Document
Contaminants Identified Under the Six- Year Health Effects Review
1
2
3
Beryllium
Chromium (total)
Fluoride
4
5
Oxamyl
Picloram
Contaminants for Which Analytical Feasibility Assessments Suggested a Potential Change
1
2
3
4
5
6
7
Benzene
Carbon tetrachloride
Chlordane
l,2-Dibromo-3-chloropropane (DBCP)
1 ,2-Dichloroethane
Dichloromethane
1 ,2-Dichloropropane
8
9
10
11
12
13
14
Heptachlor epoxide
Hexachlorobenzene
Tetrachloroethylene ("perc")
Thallium
Toxaphene
1 , 1 ,2-Trichloroethane
Trichloroethylene
Contaminants Regulated by TT Requirements
1
2
Acrylamide
Copper
3
4
Epichlorohydrin
Lead
Contaminant for Which BAT Is Not Clear or Is Incorrectly Specified
Cyanide
Contaminant for Which Public Comments Provided New Information1
Antimony?
Contaminants for Which Health Assessments Were Anticipated in 2002 or 20031
1
2
1,1-Dichloroethylene
Lindane
3
4
Toluene2
Xylenes2
1. Italicized print indicates chemicals for which new information was anticipated to be available in 2002 or 2003,
(/'. e. , information not discussed in the February draft report or the April Federal Register notice).
2. Indicates contaminants for which new health assessments had not been completed as of January 2003.
This document primarily discusses BATs specified by EPA to meet MCLs, and
technologies to meet TT-type rules. Supplemental information is provided on small systems
compliance technologies and other related treatment information. In addition, EPA has included,
as appropriate, the following: available EPA data on treatment technologies in place at
community water systems, (i.e., some baseline treatment characteristics; discussion of the
feasibility of adding treatment or modifications to existing in-place treatments; discussion of
treatment wastes as appropriate; and, general characterization of research areas that may be
pursued prior to revising an NPDWR) although, such characterization of potential research is not
meant to be exhaustive in nature, nor static. EPA is relying on available scientific and
engineering data to support this process. The end result of each contaminant-specific review
which follows is a determination of whether treatment would pose a limitation should EPA
pursue a revision to a specified standard.
This treatment review contains some recent information related to the EPA-estimated
occurrence of chemical contaminants (i.e., levels above current MCL and other threshold
Treatment Feasibility Review
June 2003
-------
values). These indicators of contaminant levels in drinking water may be relevant in the
assessment of feasibility of treatment or of making treatment modifications. Since EPA has not
decided to revise the MCLs for the contaminants reviewed in this document, this support
document does not contain nor assume any particular revised MCL values. The purpose of this
report is to review available information on treatment feasibility related to any potential EPA
revise/not revise decisions on the NPDWRs.
As mentioned above, this treatment technology document identifies areas of water
treatment research which may be required if EPA were to consider revisions to a standard.
These are identified in sections II and III, in relation to chemical MCL and TT-type rules,
respectively. Section IV, related to MCL-type rules for which analytical assessment indicated
the potential for lowering a standard, does not contain research suggestions, as none have been
identified.
The Agency is also including a discussion of potential water treatment technology in this
document to inform both the EPA drinking water program and the public. This information will
be considered within EPA's research planning process, with the longer-term aim of strengthening
regulations such that they may be more effective and implementable. Research suggestions may
also be aimed at defining new technologies that are emerging in the field, and for qualifying their
possible application to specific NPDWRs, thus providing technical information to improve one
or more aspects of treatment. The Agency continually addresses such needs, and each new
assessment of needs and resources available typically results in a modification to the research
priorities.
Ideally, research on the treatment technologies will result in specific advantages, such as
lower-cost treatments, and/or easing burdens associated with operation and maintenance. As
necessary, research may be targeted to meet the needs of certain types of water systems, (e.g.,
small water systems), or to address multiple water quality issues. Potential research areas
identified during this review are indicated at the end of each chemical discussion in sections II
and III, and summarized in section VIII of this document.
In addition to research, other processes are in place to assist in the upgrading of treatment
technology information. Among these are the Agency's periodic review of water treatment
technologies for NPDWRs, the first of which was completed, for chemical NPDWRs, in 1998
(USEPA, 1998b). Per SDWA as amended in 1996, that review focused on small systems
compliance technologies. EPA is committed to periodic review of small systems compliance
technologies, and intends to supplement that with review of new information on emerging
technologies that may be appropriate and affordable for meeting existing standards, for both
small- and large-scale drinking water systems.
II. Treatment Reviews for MCL-type Standards for Which Health Risk
Assessments Were Completed or Anticipated
The following contaminants were identified by EPA for treatment technology review
because new health risk information was available (i.e., beryllium, oxamyl and picloram), or
because new scientific reviews were anticipated (i.e., chromium and fluoride).
Treatment Feasibility Review 4 June 2003
-------
A. Beryllium
Recent EPA occurrence analyses estimated beryllium occurrence in public water systems
based on a sampling of 16 States (USEPA, 2003b). Based on these analyses, EPA estimates
indicate a total of 15 water systems (credible interval of 7 to 24)1 within these States may have a
system mean concentration exceeding the threshold of 0.004 milligrams per liter (mg/L), (i.e.,
the current MCL for beryllium). Additional occurrence estimates may be found in the above-
cited 2003 EPA report.
The current BATs for beryllium removal include activated alumina, ion exchange, lime
softening, coagulation/filtration, and reverse osmosis (USEPA, 1990b; USEPA, 1990c; 57 FR
31776 at 31809, July 17, 1992 (USEPA, 1992)). Compliance technologies for small systems
include these same five BATs, plus point-of-use (POU)-reverse osmosis, POU-ion exchange for
small systems (USEPA, 1998b). Removal efficiencies for the above-cited BATs range from 80
to 99 percent. Treatment technologies were discussed by EPA in its technical support
documentation on beryllium (USEPA, 1990c). If a treatment plant were to require upgrading,
additional ion exchange contact units may be added, POU treatment installed, or a modification
to precipitative processes added, as appropriate. The Agency's current assessment is that
treatment technology would not pose a limitation, should EPA pursue a revision to this standard.
The current BATs and small system compliance technology for beryllium also apply to
other contaminants. These treatment technologies have other beneficial effects (e.g., reduction
of hardness or other common impurities) in addition to beryllium removal. If EPA were to
consider a higher MCL, the Agency does not know how many of these public water systems
currently treating to comply with the current MCL of 0.004 mg/L would be likely to discontinue
any treatment that is already in place.
B. Chromium (Total)
1. Treatment technology
Recent EPA occurrence analyses indicate chromium occurrence in public water systems
based on a sampling of 16 States (USEPA, 2003b). Based on these analyses, EPA estimates
indicate that one water system (credible interval of 0 to 3) within these States may have a system
mean concentration exceeding the threshold of 0.1 mg/L, the current MCL for total chromium.
In addition, EPA estimates indicate a total of seven systems (credible interval of 3 to!3) within
these States may exceed the threshold of 0.05 mg/L. Additional occurrence estimates may be
found in the above-cited 2003 EPA report.
In publishing the 1989 proposed and 1991 final chromium standard (54 FR 22062 at
22105, May 22, 1989 (USEPA, 1989); 56 FR 3526 at 3552, January 30, 1991 (USEPA, 1991a))
the Agency discussed BATs which include:
• Ion exchange: 80 to 96 percent efficiency;
1 "Credible intervals" are generated to quantify the uncertainty around each estimated probability in the Bayesian
analysis of the occurrence data. For further explanation of credible intervals and the Bayesian analysis, please see
Occurrence Estimation Methodology and Occurrence Findings Report for the Six-Year Review of Existing National
Primary Drinking Water Regulations (USEPA, 2003b).
Treatment Feasibility Review 5 June 2003
-------
• Lime softening for chromium III only: 72 to 99 percent efficiency;
• Coagulation/filtration: 90 to 99 percent efficiency; and
• Reverse osmosis: 82 to 97 percent efficiency.
Due to the ionic properties of the two chromium species in water, chromium III and
chromium VI, there is a differentiation in BAT specification which may affect treatment
selection. Chromium III and chromium VI exist in water in cationic and anionic valence states,
respectively. Lime softening treatment is excluded as a BAT for anionic chromium VI.
Regarding the coagulation/filtration option, the choice of coagulant will impact chromium III
and chromium VI removal. Ferric sulfate and alum are effective for removal of chromium III,
while ferrous sulfate is effective for removal of chromium VI. Regarding ion exchange, a cation
exchange resin is required for chromium III, while an anionic resin is required for chromium VI.
Therefore, prior to use (or modification) of lime softening, ion exchange, or
coagulation/filtration treatment, a public water system should determine concentrations and
proportions of species of chromium to select proper media or chemical aid.
The 1996 SDWA Amendments require EPA to determine small system technologies for
compliance purposes, (i.e., technology designated as suitable for systems serving 25 to 10,000
persons). In 1998, EPA listed the following compliance technologies for small systems: ion
exchange, lime softening (chromium III only), coagulation/filtration, reverse osmosis, POU-
reverse osmosis, and POU-ion exchange (USEPA, 1998b).
Due to the high efficiencies of chromium removal by the above technologies, EPA
believes that existing BATs would be adequate in meeting a revised standard (if the standard
were lowered). Thus, the Agency's current assessment is that treatment technology would not
pose a limitation should EPA pursue a revision to the chromium standard.
Due to recent interest by the State of California in setting a drinking water standard for
chromium VI (the more toxic form of chromium), that State and others have initiated treatment
studies to determine the efficacy of treatment technologies in removal of chromium VI to levels
that are lower than the federal standard for total chromium. Newer treatments of interest include
an iron-based absorptive filter medium, granular ferric hydroxide (GFH), a technology that has
been piloted for arsenic removal at California water systems, and in the United Kingdom. Also,
a treatment to reduce low levels of chromium VI to chromium III in drinking water by addition
of the chemical stannous chlorine (SnCl2) is currently under investigation at a water system in
Glendale, California. EPA will monitor treatment studies to determine acceptability for use in
removal of chromium from drinking water.
2. Additional information
Of additional interest to EPA is the likelihood that disinfection treatment, including
chlorination, plays a role in transforming, by oxidation, chromium III to chromium VI in water.
The EPA Manual of Treatment Techniques for Meeting the Interim Primary Drinking Water
Regulations (USEPA, 1977) and the EPA Occurrence and Exposure Assessment for Chromium
in Public Drinking Water Supplies (USEPA, 1990a) discussed effects of chlorination on
chromium III in raw water (spiked) and in finished water. EPA found that time of contact, pH
and other factors influence oxidation of the species. In addition, a Health Canada criteria
summary on chromium in drinking water also indicated uncertainty with respect to whether post-
treatment with chlorine, affecting conversion of residual chromium III to chromium VI, may
Treatment Feasibility Review 6 June 2003
-------
reverse as water passes through iron pipes in the distribution system (Health Canada, 1986). The
testing in Glendale, California of stannous chloride as a chromium VI mitigation treatment also
includes investigation of re-oxidation of chromium III to chromium VI under various
chlorination and ammoniation treatment disinfection scenarios. While the above information
provides a minimum baseline of information on potential transformations of chromium species,
more information may be required regarding these and other potential treatment effects.
In regard to small system technologies, EPA will review available information on newer
potential treatments as research and field studies are undertaken and publicized. EPA may also
need additional data on issues related to POU-ion exchange treatment, which the Agency
discussed in a January 2001 (arsenic) Federal Register notice (66 FR 6975 at 7034, January 22,
2001 (USEPA, 200 la)). Without additional data, the Agency cannot determine if POU-ion
exchange will be a feasible compliance option, due to operational and waste discharge concerns,
and related economic issues.
3. Potential in-place treatment modifications
EPA has previously published analyses of data collected in the 1995 Community Water
System Survey (CWSS) on treatment in place at community water systems (USEPA, 2000a as
cited in USEPA, 200Ib). The data indicate that a majority of larger systems, and mainly surface
water supplied systems, are much more likely to have coagulation/filtration or lime softening
treatment in place. Some of these systems may need to modify existing treatment to allow for
more efficient removal of chromium to comply with a more stringent chromium standard. For
example, an existing lime softening plant may need to enhance the process to operate at a pH of
11 to 11.5 for optimum removal; or an existing coagulation/filtration plant may need to change
to ferric or ferrous coagulant to lower chromium levels in drinking water. The CWSS data also
indicate that small systems may need to modify or add new centralized treatment or POU
treatment to meet a standard.
The option of modifying existing treatment may be possible for a limited number of
systems, as 0.7 to 4.6 percent of small ground water systems currently have ion exchange
treatment in place. Most of these are likely to be cationic resin types (whereas anionic resins
may be required to remove excess chromium), and virtually none of the small surface water
supplies have this treatment in place. A large percentage of small (and nearly all large) surface
water supplies have either coagulation/filtration or lime softening treatment in place, whereas
only 1.5 to 8.1 percent of small ground water systems currently have coagulation/filtration or
lime softening treatment in place. However, given the occurrence information, it appears that
the majority of treatment upgrades would occur at small ground water systems, many requiring
new treatments, possibly pressurized, packaged treatment technology or other emerging
treatments mentioned above.
Tables 2a and 2b, below, contain results of the above-cited 1995 CWSS data analyses
and are provided for reference.
Treatment Feasibility Review 7 June 2003
-------
Table 2a. Ground Water Systems: Percentage of CWSs with Various Types of Treatment1
Treatment Types
Ion Exchange
Coagulation/Filtration
Lime/Soda Ash Softening
Service Population Category
25-100
0.7%
1.5%
2.1%
101-500
1.6%
5.4%
3.7%
501-1,000
3.8%
4.2%
4.1%
1,001-3,300
1.9%
3.4%
5.2%
3,301-10,000
4.6%
8.1%
7.0%
1 Treatment information from 1995 Community Water System Survey as summarized in Geometries and
Characteristics of Public Water Systems (USEPA, 2000a as cited in USEPA, 200 Ib).
Table 2b. Surface Water Systems: Percentage of CWSs with Various Types of Treatment1
Treatment Types
Ion Exchange
Coagulation/Filtration
Lime/Soda Ash Softening
Service Population Category
25-100
0%
27.5%
3.9%
101-500
0%
52.6%
8.1%
501-1,000
0%
70.2%
20.5%
1,001-3,300
0%
78.5%
17.5%
3,301-10,000
0%
95.4%
10.8%
1 Treatment information from 1995 Community Water System Survey as summarized in Geometries and
Characteristics of Public Water Systems (USEPA, 2000a as cited in USEPA, 200 Ib).
4.
Potential chromium treatment research
Prior to conducting analyses in support of an NPDWR revision, should a more stringent
chromium MCL be considered, EPA would need to review literature and/or conduct new
treatment research. This may include documentation of bench, pilot, and/or full-scale studies on
GFH, other adsorption media, and membrane technologies. POU-ion exchange studies on
chromium removal may be required, including tests on efficacy of treatment and disposal of
related wastes. Studies may include optimization of centralized ion exchange treatment
efficiency and waste treatment and handling/disposal. Effects of disinfection treatments, as well
as addition of reducing agents such as SnCl2 on chromium in water may require further study
should a more stringent chromium MCL be considered. These needs would be forwarded to the
appropriate office within EPA to be considered for research.
C. Fluoride
1. Treatment technology
Recent EPA occurrence analyses indicate fluoride occurrence in public water systems
based on a sampling of 16 States (USEPA, 2003b). Based on these analyses, EPA estimates
indicate that a total of 106 water systems (credible interval of 91 to 123) within these States may
have a system mean concentration exceeding the threshold of 4 mg/L, the current MCL for
fluoride. In addition, EPA estimates indicate a total of 603 (credible interval of 566 to 640)
water systems within these States may exceed the threshold of 2 mg/L. Additional occurrence
estimates may be found in the above-cited 2003 EPA report.
Treatment Feasibility Review
June 2003
-------
The 1986 final fluoride regulation set "best technologies generally available" (BTGAs) as
activated alumina and reverse osmosis. BTGA was defined prior to the SDWA Amendments of
1986, based upon measures of technological efficiency and economic accessibility (i.e.,
"reasonably affordable by regional and large metropolitan public water systems"). The
following factors were considered in determination of BTGA: high removal rate; wide
applicability; compatibility with other treatments; and ability to achieve compliance for all water
in the public water system (51 FR 11396 at 11398, April 2, 1986 (USEPA, 1986)). These
requirements are comparable with current SDWA requirements for BAT determination.
In addition, the 1996 SDWA amendments require EPA to determine small system
technologies for compliance purposes, (i.e., technology designated as suitable for systems
serving 25 to 10,000 persons). In 1998, EPA listed small system compliance technologies,
including both centralized activated alumina and reverse osmosis treatment, as well as POU-
reverse osmosis, for removal of fluoride in drinking water (USEPA, 1998b).
The Agency does not believe that the "BTGA" or small systems compliance technologies
pose a problem. In addition, should a revision to the designation of "BATs" for this contaminant
be considered by EPA, in lieu of the originally specified "BTGA" designation, this would
represent a minor revision to the NPDWR (see 40 CFR 141.62 for MCLs for Inorganic
Contaminants; and 40 CFR 142.61, which specifies variance technologies for fluoride).
Previously published research and EPA technologies and costs documents (USEPA,
1985b) on these technologies indicate that, due to high efficiencies of removal, the above-cited
treatment technologies would not be a limiting factor in setting a lower fluoride MCL.
Efficiencies of removal range from 85 to 95 percent, depending upon treatment system design.
Thus, the Agency's current assessment is that treatment technology would not pose a limitation
should EPA pursue a revision to the fluoride standard.
Both activated alumina and reverse osmosis treatment remove arsenic and fluoride
among other impurities. Using activated alumina treatment, optimum removals for both
contaminants may occur in a similar range of pH 5.5 to pH 6 (USEPA, 1985b; USEPA, 2000b).
However, because arsenic V and silica are preferentially adsorbed by activated alumina media,
effectiveness of activated alumina where arsenic and fluoride co-occur may require some
investigation. Another activated alumina treatment shortcoming, discussed further below, is the
operational difficulty of adding pH adjustment for optimizing removal efficiency (i.e., adjusting
pH prior to and after treatment). For some small systems, treatment may be limited to using
"natural" pH levels (i.e., unadjusted) thus sacrificing some removal efficiency. However, this
application for fluoride removal is not documented.
The Agency discussed technical issues related to activated alumina technology in the
above-cited fluoride final rule, including waste generation and disposal. More recent EPA
publications have also examined the operation of activated alumina technology and perceived
difficulties posed by chemical handling by small systems, (i.e., for pH adjustment and for
regeneration of the media), as well as the alternatives to regeneration of activated alumina media.
In the case of arsenic treatment, the Agency recommended against the regeneration of activated
alumina media at both small centralized treatment and POU applications, due in part to the
difficulty of disposing of brine wastes. EPA instead assumed that spent activated alumina media
would be disposed of directly at a landfill on a "throw-away" basis and that, based upon arsenic
toxicity characteristic leaching procedure (TCLP) testing, this waste would not be deemed
Treatment Feasibility Review 9 June 2003
-------
"hazardous" (USEPA, 2000b; 66 FR 6975, January 22, 2001 (USEPA, 200la)). However,
except where arsenic and fluoride were being co-treated, this information should not (alone) be
applied to fluoride treatment wastes because Resource Conservation and Recovery Act (RCRA)
regulations do not regulate fluoride under the toxicity characteristic hazardous waste
identification rule (40 CFR 261.24). That stated, there may be concerns regarding waste brine
(i.e.., regenerate solution) that have not yet been anticipated.
As part of recent revisions to the arsenic standard, the Agency also addressed the issue of
treatment optimization (pH adjustment) for POU-activated alumina systems. For arsenic, EPA
determined that use of POU (and point-of-entry (POE))-activated alumina would be limited due
to the practical limitation of adjusting pH and then re-adjusting after treating for corrosion
control. The Agency considered the option of using activated alumina at an unadjusted "natural
pH" range of 7 to 8 as the probable application at very small systems due to the operational
capabilities that are required to properly adjust pH (USEPA, 2000b; 66 FR 6975, January 22,
2001 (USEPA, 200la)).
While not currently a "BTGA" or "BAT", modified lime softening (30 to 70 percent
removal) may also be used where this treatment is in place to remove excess fluoride (USEPA,
1985b).
The following summarizes additional information that may relate to setting, revising,
and/or applying the above two BATs and the POU compliance option for fluoride.
2. Potential in-place treatment modifications
Cost of treatment may drive systems that have fluoride above the compliance level to the
less expensive option (i.e., activated alumina), or to newer treatments as they become available.
Where de-fluoridation treatment is already in place, due to prior exceedance of the current
fluoride MCL, systems may opt to increase the proportion of water treated, or add more capacity
to existing treatment (or additional media vessels in series). Because centralized treatment may
be less economically feasible for very small systems, some may install POU treatment (with
reverse osmosis being the more likely choice). POU treatment may also present operational
advantages and additional treatment benefits. The B ATs are known to remove fluoride and
arsenic (arsenic V is preferentially adsorbed by activated alumina media). Reverse osmosis
treatment would remove additional regulated and secondary contaminants, such as total
dissolved solids, hardness, iron, and manganese, which may co-occur with fluoride in water.
EPA's 1995 CWSS data is summarized and has been utilized in recent EPA technical
support materials (USEPA, 2000a as cited in USEPA, 200Ib). These provide some
understanding of numbers and types of treatments in place at community water systems.
However, they do not specifically include activated alumina treatment information. Therefore, it
is not possible to estimate a relationship between systems now treating with activated alumina,
and those that may need to treat further to meet a lower standard. However, in areas with high
background levels (especially if above 4 mg/L), treatment of fluoride may already be in place.
The followup 2000 CWSS results are expected to include activated alumina treatment
information and these will be available in the 2003 time frame.
The CWSS summary tables indicate (see Tables 2a and 2b) that lime/soda ash softening
capacity exists and may provide, especially for surface water systems, a base for increased
Treatment Feasibility Review 10 June 2003
-------
fluoride removal via enhanced lime softening treatment.
3. Potential fluoride treatment research
Prior to conducting analyses in support of an NPDWR revision, if that were necessary,
EPA would review pertinent literature and/or conduct new treatment research. In 2002, EPA
initiated and drafted a literature review on fluoride treatment processes (which the Agency is
maintaining in draft status, as it may require future updating) (USEPA, 2002c). Review of the
literature, in the future, may lead to additional potential research areas. These may be further
pursued through documentation of bench, pilot, and/or full-scale studies, related to treatment
effectiveness; engineering studies on existing BATs; or other treatment processes.
Documentation and/or study of waste treatment, handling and disposal, and POU treatment
studies may also be required should a more stringent fluoride MCL be considered. These needs
would be forwarded to the appropriate office within EPA to be considered for research.
Unrelated to the above potential fluoride treatment research, the Agency has initiated an
investigation of the kinetics and equilibria of the chemicals used in water fluoridation. This
work would contribute to the understanding of how fluoridation chemicals dissociate in finished
water. The Agency funded this project, which is underway and expected to be completed in the
2005 time frame.
D. Oxamyl
Recent EPA occurrence analyses indicate oxamyl occurrence in public water systems
based on a sampling of 16 States (USEPA, 2003b). Based on these analyses, EPA estimates
indicate zero (number and percent) water systems within these States may have a system mean
concentration exceeding the threshold of 0.2 mg/L, the current MCL for oxamyl. Additional
occurrence estimates may be found in the above-cited 2003 EPA report.
The current BAT is granular activated carbon (GAC), and removal efficiency ranges
from 85 to 95 percent depending upon design parameters (USEPA, 1990b; 55 FR 30370 at
30416, July 25, 1990 (USEPA, 1990d), 57 FR 31776 at 31809, July 17, 1992 (USEPA, 1992)).
Compliance technologies for small systems include: GAC, powdered activated carbon (PAC),
and POU-GAC (USEPA, 1998b).
If water treatment systems were to require upgrading, additional GAC contactor(s) may
be added or PAC added, as appropriate. Given available information on treatment efficacy and
on occurrence levels, the Agency's current assessment is that treatment technology would not
pose a limitation should EPA pursue a revision to this standard.
E. Picloram
Recent EPA occurrence analyses indicate picloram occurrence in public water systems
based on a sampling of 16 States (USEPA, 2003b). Based on these analyses, EPA estimates
indicate zero (number and percent) water systems within these States may have a system mean
concentration exceeding the threshold of 0.5 mg/L, the current MCL for picloram. Additional
occurrence estimates may be found in the above-cited 2003 EPA report.
The current BAT for picloram removal is GAC treatment. Treatment technologies were
discussed by EPA in its technical support documentation (USEPA, 1990b; 55 FR 30370 at
Treatment Feasibility Review 11 June 2003
-------
30416, July 25, 1990 (USEPA, 1990d), 57 FR 31776 at 31809, July 17, 1992 (USEPA, 1992)).
Small systems compliance technologies are GAC, PAC, and POU-GAC (USEPA, 1998b).
If treatment were to require upgrading, additional GAC contact units may be added or
POU treatment installed. Given available information on treatment efficacy and on occurrence
levels, the Agency's current assessment is that treatment technology would not pose a limitation
should EPA pursue a revision to this standard.
The current BATs and small system compliance technologies for picloram also apply to
other contaminants. These treatment technologies have other beneficial effects (e.g., reduction
of organics or other common impurities) in addition to picloram removal. If EPA were to
consider a higher MCL, the Agency does not know how many public water systems currently
treating to comply with the current MCL of 0.5 mg/L would be likely to discontinue any
treatment that is already in place.
III. Treatment Review for Chemical Contaminants Regulated by Treatment
Technique (TT) Requirements
This section contains a brief review of required treatment technologies for those
contaminants with TT-based NPDWRs, including acrylamide, epichlorohydrin, and the Lead and
Copper Rule (LCR).
As allowed under SDWA, in cases where EPA determines it is not technically or
economically feasible to establish an MCL, the Agency can instead specify a TT rule. TT rules
established treatment methods to minimize the level of a contaminant in drinking water.
A. Acrylamide and Epichlorohydrin
EPA regulations for acrylamide and epichlorohydrin, including polymer addition
practices, were discussed in Federal Register notices of 1989 and 1991 (54 FR 22062 at 22105,
May 22, 1989 (USEPA, 1989); 56 FR 3526 at 3552, January 30, 1991 (USEPA, 1991a)). EPA
has no new information that suggests it is appropriate to revise the TT requirements for
acrylamide and epichlorohydrin at this time.
B. Lead and Copper Rule
The LCR requires the mitigation of lead and copper in public drinking water supplies
through treatments, mainly through optimizing corrosion control treatment and through related
monitoring strategies (56 FR 26460, June 7, 1991 (USEPA, 1991b)).
The LCR establishes treatment-type measures to control levels of lead and copper in
public drinking water, including corrosion control treatment requirements for small, medium,
and large water systems. Treatment may be triggered following sampling and analysis of tap
water, if the value at the 90th percentile of all lead or copper samples is higher than the lead or
copper action levels of 0.015 mg/L or 1.3 mg/L, respectively.
Treatment Feasibility Review 12 June 2003
-------
Under the LCR, public water systems that are required to conduct corrosion control
studies must evaluate the effectiveness of each of the following treatments and, if appropriate,
combinations of the following treatment:
Alkalinity and pH adjustment;
Calcium hardness adjustment; and
Addition of a phosphate or silicate based corrosion inhibitor.
Public water systems are also required to monitor for lead and copper, and the following
water quality parameters, before and after evaluating the above treatments: pH, alkalinity,
calcium, conductivity, orthophosphate or silicate (where added), and water temperature. Water
systems must identify constraints that limit or prohibit the use of a particular corrosion control
treatment(s), and evaluate effect(s) of corrosion control chemicals on other water quality
treatment processes. On the basis of the above, a public water system recommends the treatment
option best suited for its system, and the State review agency considers the public water system
information, and then designates optimal treatment for that system.
EPA has no information that suggests it is appropriate to revise the current TT
requirements for lead and copper. However, EPA received public comments on the Agency's
preliminary decisions, published in the April 17, 2002, Federal Register., which indicate that
there is an interest in examining treatment and other aspects of the LCR (67 FR 19030 (USEPA,
2002a)). The Agency recognizes that there are challenging aspects to this rule, and that more
research would be useful to obtain additional information that could be utilized to address some
of the issues associated with implementation of the LCR.
Because no new data are available to make a revise/not revise determination, EPA has
decided to place lead in the "data gaps" category, indicating that research may need to be
completed prior to making further determinations. Copper has been placed in another category,
because an EPA copper health effects assessment is underway and must be completed before
EPA can determine if a revision to the NPDWR is warranted. Nonetheless, some of the potential
research that is indicated below could affect the control of both copper and lead.
EPA believes that research on treatment aspects of the LCR, (i.e., on effective corrosion
control measures), and on other pertinent issues affecting implementation, may be appropriate.
The following list represents the Agency's current understanding of general needs that may be
filled by research to better inform future reviews of the NPDWR:
Investigation of effects related to compliance with the LCR and the requirements
related to disinfectants and disinfection byproducts.
• Investigation of corrosion control chemicals, including optimization and use of
chemicals, constraints related to distribution system materials, possible secondary
effects, and alternative approaches to current corrosion control strategies.
• Other needs including: investigation of optimization of corrosion control at
systems with high alkalinity and/or hardness in source water; monitoring (e.g.,
targeted monitoring to represent copper levels); and small systems LCR treatment
compliance issues, that may be of considerable interest.
Treatment Feasibility Review 13 June 2003
-------
The above represents a current synopsis of the most critical research areas related to the
LCR. It is not intended to be all-inclusive nor a static listing of subject areas. The February
2002 draft version of this report included a longer listing. The above combines some of the
issues and adds others. EPA believes that the above-listed items would take variable periods of
time to complete, and would most likely be done in steps. In addition, they may be handled by
more than one party, depending on interests and relative priorities, available funding, and other
critical factors. Determining the most effective use of resources and the exact nature of research
would require additional study/discussion.
EPA includes priority research within its multi-year planning process, and in its
comprehensive drinking water research strategy. These help EPA prioritize and plan future
research and help the Agency track current efforts. The Agency reviews plans periodically and
changes them as necessary. In addition, EPA expects to further explore LCR-related research
needs within the Agency, and with interested stakeholders, to inform future Agency decisions.
IV. Chemical Contaminants With MCLs Limited by Analytical Feasibility
This section includes a brief treatment technology assessment of chemicals currently
regulated at MCL values that were based on analytical feasibility. More recent EPA assessments
of analytical feasibility indicate the potential for lower practical quantitative levels (PQLs) for
these contaminants (USEPA, 2003 c).
For all contaminants discussed in this section, the Agency's current assessment is that
treatment technology would not pose a limitation should EPA pursue a revision to any of the
referenced standards. Chemical occurrence is not referenced for these contaminants, since the
known occurrence levels for these (USEPA, 2003b) would not pose an obstacle to specification
of treatments. Likewise, MCL values for these contaminants are not referenced.
A. Volatile Organic Contaminants
1. Benzene, Carbon Tetrachloride, 1, 2-dichloroethane, and Trichloroethylene
Since the results of the analytical methods feasibility review indicate that it may be
possible to recalculate the PQL for benzene; carbon tetrachloride; 1, 2-dichloroethane; and
trichloroethylene, EPA has reviewed treatment feasibility for these contaminants to determine if
it is likely to become an issue if EPA were to revise any of their MCLs. The BATs for each of
these contaminants are packed tower aeration (PTA) and GAC (56 FR 3526 at 3552, January 30,
1991 (USEPA, 199la)). Small system compliance technologies for each include: PTA, diffused
aeration, multi-stage bubble aerators, tray aeration, shallow tray aeration, and GAC (USEPA,
1998b).
The Agency discussed treatment for volatile organic chemicals (VOCs) in the 1985
proposed VOC regulation (50 FR 46902 at 46909, November 13, 1985 (USEPA, 1985a)). Under
optimum conditions, up to 99.9 percent removal of VOCs may be achieved by aeration
technology, and the Agency considers 99 percent reduction to be achievable under all anticipated
conditions. In addition, in the above-cited proposed rule, EPA discussed GAC treatment for
VOCs, and considers 99 percent removal to be achievable under all anticipated conditions.
Thus, treatment is not known to be a limiting concern for any of the current MCLs for these four
contaminants: benzene; carbon tetrachloride; 1, 2-dichloroethane; and trichloroethylene. Based
Treatment Feasibility Review 14 June 2003
-------
on this information, EPA's current assessment is that treatment technology would not pose a
limitation, should the Agency consider revising any of their current MCLs.
2. l,2-Dibromo-3-chloropropane(DBCP)
Since the results of the analytical methods feasibility review indicate that it may be
possible to recalculate the PQL for DBCP, EPA has reviewed treatment feasibility to determine
if it is likely to become an issue if EPA were to revise the MCL. BATs include aeration and
GAC (54 FR 22062 at 22105, May 22, 1989 (USEPA,1989); 56 FR 3526 at 3552, January 30,
1991 (USEPA, 199la)), and compliance technologies for small systems include GAC, PAC, and
POU-GAC (USEPA, 1998b). Treatment is not known to be a limiting concern for the current
MCL.
Since the Henry's coefficient for this contaminant is relatively low (i.e., 1 atmospheres
DBCP, which is considered "less strippable" than other contaminants), GAC may in some cases
be the preferred treatment. Based on this information, EPA's current assessment is that treatment
technology would not pose a limitation should the Agency consider revising the current MCL.
3. Dichloromethane (Methylene Chloride)
Since the results of the analytical methods feasibility review indicate that it may be
possible to recalculate the PQL for dichloromethane, EPA has reviewed treatment feasibility to
determine if it is likely to become an issue if EPA were to revise the MCL. As a VOC, the BAT
for dichloromethane is PTA (57 FR 31776 at 31809, July 17, 1992 (USEPA, 1992)). Small
system compliance technologies include: PTA, diffused aeration, multi-stage bubble aerators,
tray aeration, shallow tray aeration, and GAC (USEPA, 1998b). Treatment is not known to be a
limiting concern for the current MCL.
The Agency discussed treatment for VOCs in the 1985 proposed VOC regulation (50 FR
46902 at 46909, November 13, 1985 (USEPA, 1985a)). Under optimum conditions, up to 99.9
percent removal of VOCs may be achieved by aeration technology, and the Agency considers 99
percent reduction to be achievable under all anticipated conditions. Based on this information,
EPA's current assessment is that treatment technology would not pose a limitation, should the
Agency consider revising the current MCL.
4. 1,2-Dichloropropane
Since the results of the analytical methods feasibility review indicate that it may be
possible to recalculate the PQL for 1,2-dichloropropane, EPA has reviewed treatment feasibility
to determine if it is likely to become an issue if EPA were to revise the MCL. BATs for 1,2-
dichloropropane includes both PTA and GAC (54 FR 22062 at 22105, May 22, 1989 (USEPA,
1989); 56 FR 3526 at 3552, January 30, 1991 (USEPA, 1991a)). Small system compliance
technologies include: PTA, diffused aeration, multi-stage bubble aerators, tray aeration, shallow
tray aeration, and GAC (USEPA, 1998b). Treatment is not known to be a limiting concern for
the current MCL.
Among volatile contaminants, this contaminant exhibits "average strippability" (54 FR
22062 at 22105, May 22, 1989 (USEPA, 1989)). The Agency discussed treatment for VOCs in
the 1985 proposed VOC regulation (50 FR 46902 at 46909, November 13, 1985 (USEPA,
1985a)). Under optimum conditions, up to 99.9 percent removal of VOCs may be achieved by
Treatment Feasibility Review 15 June 2003
-------
aeration technology, and the Agency considers 99 percent reduction to be achievable under all
anticipated conditions. Based on this information, EPA's current assessment is that treatment
technology would not pose a limitation, should the Agency consider revising the current MCL.
5. Tetrachloroethylene ("Perc")
Since the results of the analytical methods feasibility review indicate that it may be
possible to recalculate the PQL for tetrachloroethylene, EPA has reviewed treatment feasibility
to determine if it is likely to become an issue if EPA were to revise the MCL. BATs for
tetrachloroethylene include PTA and GAC (56 FR 3526 at 3552, January 30, 1991 (USEPA,
199la)), and small systems compliance technologies include: PTA, diffused aeration, multi-
stage bubble aerators, tray aeration, shallow tray aeration, and GAC (USEPA, 1998b).
Treatment is not known to be a limiting concern for the current MCL.
The high level of volatility of tetrachloroethylene is reflected in this chemical's Henry's
Law Coefficient of 214.0 atmospheres. Design of air stripping equipment was discussed in the
proposal for this NPDWR. Several factors which affect engineering design include: air-to-water
ratio; packed material height; available area for mass transfer; water and air temperature; and
physical chemistry of the contaminant (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989)).
Tetrachloroethylene, while volatile, is also highly amenable to GAC adsorption treatment.
Carbon use rates for this contaminant are relatively low.
The Agency discussed treatment for VOCs in the 1985 proposed VOC regulation (50 FR
46902 at 46909, November 30, 1985 (USEPA, 1985a)). Under optimum conditions, up to 99.9
percent removal of VOCs may be achieved by aeration technology, and the Agency considers 99
percent reduction to be achievable under all anticipated conditions. Based on this information,
EPA's current assessment is that treatment technology would not pose a limitation, should the
Agency consider revising the current MCL.
B. Other Contaminants
1. Chlordane
The BAT for chlordane is GAC (56 FR 3526 at 3552, January 30, 1991 (USEPA,
199la)). Treatment is not known to be a limiting concern for the current MCL. However, since
the results of the analytical methods feasibility review indicate that it may be possible to
recalculate the PQL for chlordane, EPA has reviewed treatment feasibility. Chlordane is a
moderately adsorbed pesticide (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989); 56 FR
3526 at 3552, January 30, 1991 (USEPA, 1991a)). Therefore, EPA's current assessment is that
treatment technology is not anticipated to pose a limitation, should the Agency consider revising
the current MCL.
2. Heptachlor
The BAT for heptachlor is GAC (56 FR 3526 at 3552, January 30, 1991 (USEPA,
199la)), and small systems compliance technologies include: GAC, POU-GAC, and PAC
(USEPA, 1998b). Since the results of the analytical methods feasibility review indicate that it
may be possible to recalculate the PQL for heptachlor, EPA has reviewed treatment feasibility to
determine if it is likely to become an issue if EPA were to revise the MCL. Treatment is not
known to be a limiting concern for the current MCL.
Treatment Feasibility Review 16 June 2003
-------
Heptachlor is a moderately adsorbed organic contaminant (54 FR 22062 at 22105, May
22, 1989 (USEPA, 1989); 56 FR 3526 at 3552, January 30, 1991 (USEPA, 1991a)). EPA's
preliminary assessment is that treatment technology is not anticipated to pose a limitation should
the Agency consider revising the current MCL.
3. Heptachlor Epoxide
The BAT for heptachlor epoxide is GAC (56 FR 3526 at 3552, January 30, 1991
(USEPA, 199la)), and compliance technologies for small systems include GAC, PAC, and POU-
GAC (USEPA, 1998b). Since the results of the analytical methods feasibility review indicate
that it may be possible to recalculate the PQL for heptachlor epoxide, EPA has reviewed
treatment feasibility to determine if it is likely to become an issue if EPA were to revise the
MCL. Treatment is not known to be a limiting concern for the current MCL.
Heptachlor epoxide is a strongly adsorbed organic contaminant, generally attributed to a
low carbon usage rate (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989); 56 FR 3526 at
3552, January 30, 1991 (USEPA, 1991a)). Based on this information, EPA's current assessment
is that treatment technology is not anticipated to pose a limitation should the Agency consider
revising the current MCL.
4. Hexachlorobenzene
The BAT for hexachlorobenzene is GAC (57 FR 31776 at 31809, July 17, 1992 (USEPA,
1992)), and compliance technologies for small systems include GAC, PAC, and POU-GAC
(USEPA, 1998b). Since the results of the analytical methods feasibility review indicate that it
may be possible to recalculate the PQL for hexachlorobenzene, EPA has reviewed treatment
feasibility to determine if it is likely to become an issue if EPA were to revise the MCL.
Treatment is not known to be a limiting concern for the current MCL.
Since hexachlorobenzene is a moderately adsorbed contaminant, EPA's current
assessment is that treatment technology is not anticipated to pose a limitation should the Agency
consider revising the current MCL.
5. Thallium
BATs for thallium include activated alumina and ion exchange (57 FR 31776 at 31809,
July 17, 1992 (USEPA, 1992)). EPA also listed small systems compliance technologies for this
contaminant as activated alumina, ion exchange, POU-ion exchange (USEPA, 1998b). Since the
results of the analytical methods feasibility review indicate that it may be possible to recalculate
the PQL for thallium, EPA has reviewed treatment feasibility to determine if it is likely to
become an issue if EPA were to revise the MCL. Treatment is not known to be a limiting
concern for the current MCL.
According to technical information provided previously by EPA for thallium, competing
ions in water may affect treatment run lengths (USEPA, 1998b). Assuming reasonable
engineering practices, high removals of this contaminant are feasible. Removals may be
expected to be greater than 90 percent using cation exchange systems, and greater than 95
percent using activated alumina treatment (55 FR 30370 at 30416, July 25, 1990 (USEPA,
1990d)). Based on this information, EPA's current assessment is that treatment technology is not
anticipated to pose a limitation should the Agency consider revising the current MCL.
Treatment Feasibility Review 17 June 2003
-------
6. Toxaphene
The BAT for toxaphene is GAC (56 FR 3526 at 3552, January 30, 1991 (USEPA,
199la)), and small systems compliance technologies include: GAC, POU-GAC, and PAC
(USEPA, 1998b). Since the results of the analytical methods feasibility review indicate that it
may be possible to recalculate the PQL for toxaphene, EPA has reviewed treatment feasibility to
determine if it is likely to become an issue if EPA were to revise the MCL. Treatment is not
known to be a limiting concern for the current MCL.
According to technical information provided with the final NPDWR for toxaphene, this
compound is among those that are moderately to well-adsorbed, exhibiting a relatively low
carbon usage rate (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989); 56 FR 3526 at 3552,
January 30, 1991 (USEPA, 1991a)). Assuming reasonable engineering practices, high removals
of this contaminant are feasible. Based on the above information, EPA's current assessment is
that treatment technology is not anticipated to pose a limitation should the Agency consider
revising the current MCL.
7. 1,1,2-Trichloroethane
BATs for 1,1,2-trichloroethane includes both PTA and GAC (57 FR 31776 at 31809, July
17, 1992 (USEPA, 1992)). Small systems compliance technologies for this contaminant include:
PTA; diffused aeration; multi-stage bubble aerators; tray aeration; shallow tray aeration; and
GAC (USEPA, 1998b). Since the results of the analytical methods feasibility review indicate
that it may be possible to recalculate the PQL for 1,1,2-trichloroethane, EPA has reviewed
treatment feasibility to determine if it is likely to become an issue if EPA were to revise the
MCL. Treatment is not known to be a limiting concern for the current MCL.
According to technical information provided by EPA within the final NPDWR for 1,1,2-
trichloroethane, this compound is among those moderately adsorbed chemicals, exhibiting a
moderate carbon usage rate (57 FR 31776 at 31809, July 17, 1992 (USEPA, 1992)). 1,1,2-
Trichloroethane may be among the less volatile organic chemicals (55 FR 30370 at 30416, July
25, 1990 (USEPA, 1990d)). Assuming reasonable engineering practices, treatment for removal
of this contaminant is feasible. Based on this information, EPA's current assessment is that
treatment technology is not anticipated to pose a limitation should the Agency consider revising
the current MCL.
V. Contaminant for Which BAT Is Not Clear or Is Incorrectly Specified
BATs for cyanide include ion exchange, reverse osmosis, and "chlorine" treatment (57
FR 31776 at 31809, July 17, 1992 (USEPA, 1992)). CFR §141.62 and §142.62 contain
erroneous BAT designations for cyanide. These will need to be revised to read "alkaline
chlorination" in place of "chlorine" as a BAT for cyanide. EPA will publish a. Federal Register
notice to make the appropriate corrections to the cyanide regulation.
EPA discussed chlorination in the proposed and final regulations for cyanide (55 FR
30370 at 30416, July 25, 1990 (USEPA, 1990d); 57 FR 31776 at 31809, July 17, 1992 (USEPA,
1992)). The Agency discussed the effectiveness of oxidation of cyanide at high pH in the related
Treatment Feasibility Review 18 June 2003
-------
technology support document (USEPA, 1990c). Thus, the Agency had technically described the
correct treatment (i.e., the use of chlorination at elevated pH conditions) but had an error in the
published listings of BATs.
In addition, since this standard was promulgated, EPA distributed a "Public Water
System Warning" (USEPA, 1994) through its regional offices. This warning included
information on the use of chlorination (non-alkaline) and the potential for formation of harmful
cyanogen chloride, due to reaction of chlorine with cyanide in water under those conditions.
This warning also states, "EPA will change the regulations specifying BAT for removing
cyanide from chlorination to alkaline chlorination."
Alkaline chlorination, through use of excess chlorine at pH values greater than 8.5,
oxidizes cyanide to harmless bicarbonate and nitrogen gas. The higher the pH, the faster this
reaction proceeds. The "Public Water System Warning" explains this process in detail and
outlines treatment practice, including contact times, required chlorine concentrations, and
compensation for temperature effects.
VI. Contaminant for Which Public Comments on EPA's Review Provided
New Information
The MCL for antimony is 6 micrograms per liter (|ig/L). EPA discussed BATs for
antimony (i.e.., coagulation/filtration and reverse osmosis) in the proposed and final regulations
for this contaminant (55 FR 30370 at 30416, July 25, 1990 (USEPA, 1990d); 57 FR 31776 at
31809, July 17, 1992 (USEPA, 1992)). Small systems compliance technologies for antimony
include reverse osmosis and coagulation/filtration, and POU-reverse osmosis (USEPA, 1998b).
Prior to promulgating this regulation, EPA conducted laboratory tests to determine
treatment removal efficiencies on source water that had been spiked with antimony to a
relatively high level, approximately 100 |ig/L.
Following publication of the April 17, 2002, Federal Register notice with the preliminary
Six-Year Review findings (67 FR 19030 (USEPA, 2002a)), the Agency received several
comments from parties in Utah which indicated a difficulty in implementing the antimony
standard. A few small systems have levels of antimony in their source water at or above the
MCL value of 6 jig/L (i.e., at levels between 6 and 19 |ig/L).
Some of these systems have been investigating treatment options for the removal of
antimony from their source water. Commenters submitted supporting data documenting the
results of their testing and cost analyses. According to commenters, on-site testing indicated that
the designated BATs (i.e., reverse osmosis and coagulation/filtration) and most of the other
tested treatments were ineffective and/or prohibitively expensive due to: raw water quality
concerns; water conservation needs; current costs for water production; and other concerns, such
as waste water management. In addition, commenters indicated that coagulation/filtration
assisted by microfiltration was unsuccessful in the removal of antimony to the MCL. These
commenters noted other concerns that included: the handling of treatment chemicals, safety, and
pretreatment of water. Commenters also pointed to the marked difference between the ambient
water levels, at their systems, and the value at which EPA had tested the BATs.
Treatment Feasibility Review 19 June 2003
-------
Commenters also indicated that one technology that they tested, GFH, was very
promising for antimony removal, in regard to its efficiency and operational parameters. Relative
cost evaluations were also conducted. Cost analyses for the Salt Lake County Service Area No.
3 site in Snowbird, Utah, indicated that GFH may be the lowest-cost treatment option, at a total
annualized (capital and operations and maintenance included) cost of $1.80/kgal, compared to
approximately $3.90/kgal for reverse osmosis treatment. In addition to the cost issue,
commenters said that reverse osmosis presented waste disposal problems and was not an
acceptable option due to the volume of wasted water.
EPA believes that, should a decision be made to revise this standard (i.e., to a lower
level), or if the Agency determined that the occurrence of this contaminant is more widespread
than currently believed, there may be a need for further research on antimony treatment removal
technologies. Results of research may be useful for expanding the technology information base
for this NPDWR. (Note that EPA is prohibited from making revisions to an MCL based on
feasibility unless such changes maintain or provide for greater health protection.) The scope and
priority of research for antimony treatment has yet to be determined by EPA. The level of
priority will be better understood when the Agency has completed an assessment of the antimony
health risk information.
VII. Contaminants for Which Additional Health Assessments Were
Completed in 2002 or Were Anticipated in 2003
This section includes a brief treatment technology assessment of regulated chemicals for
which health assessments were recently completed or were possibly going to be completed prior
to, or soon after the close of the 1996 - 2002 Six-Year Review. These contaminants include, 1,1-
dichloroethylene, lindane, toluene, and xylene.
A. 1,1-Dichloroethylene
The current MCL for 1,1-dichloroethylene is 0.007 mg/L. BATs and small system
compliance technologies for 1,1-dichloroethylene include aeration and GAC (56 FR 3526 at
3552, January 30, 1991 (USEPA, 1991a); USEPA, 1998b). These treatment technologies also
apply to other contaminants and have other beneficial effects (e.g., removal or reduction of other
organics and other common impurities), in addition to removal of 1,1-dichloroethylene from
water. Therefore, if EPA were to raise the MCLG/MCL, the Agency believes that few, if any,
public water systems currently treating to comply with the current MCL would be likely to
discontinue any such treatment that is already in place (USEPA, 2002d).
B. Lindane
The current MCL for this contaminant is 0.0002 mg/L. BAT and small system
compliance technology for lindane is GAC (57 FR 31776 at 31809, July 17, 1992 (USEPA,
1992); USEPA, 1998b). This treatment technology also applies to removal or reduction of other
contaminants and has other beneficial effects (e.g., removal or reduction of other organics and
other common impurities), in addition to removal of lindane in water. Therefore, if EPA were to
raise the MCLG/MCL, the Agency believes that few, if any, public water systems currently
treating to comply with the current MCL would be likely to discontinue any such treatment that
is already in place (USEPA, 2002d).
Treatment Feasibility Review 20 June 2003
-------
C. Toluene
The current MCL for toluene is 1 mg/L. The current BATs and small system compliance
technologies for toluene include several forms of aeration and GAC (57 FR 31776 at 31809, July
17, 1992 (USEPA, 1992); USEPA, 1998b).
Field studies performed in three States using PTA demonstrated a removal efficiency of
greater than 96 percent for toluene, with initial concentrations of up to 0.6 mg/L (Ram et a/.,
1990 as cited in USEPA, 1998b). Performance studies employing diffused aeration, which is
another air stripping technology used to treat toluene, have demonstrated 50 to 90 percent
removal efficiencies. The study noted higher removals for VOCs that had higher Henry's Law
coefficients (USEPA, 1985b as cited in USEPA, 1998a).
GAC may also be an effective treatment option for toluene, although based on cost
estimates (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989)), it may be more than twice as
expensive as PTA for large systems on a dollar per household per year basis. If off-gas control
of PTA is necessary, costs between PTA and GAC are more competitive, but PTA is still likely
to be more cost-effective for system sizes up to 1 to 10 million gallons per day (Adams and
Clark, 1991). Specific cost information for GAC and PTA control of toluene is available
(Adams et al, 1989; Adams and Clark, 1991). Based on this information, EPA does not
anticipate that treatment would pose a limitation should the Agency consider revising the current
standard(s) for toluene.
D. Xylenes
The current MCL for total xylenes is 10 mg/L. The current BATs and small system
compliance technologies for xylenes include several forms of aeration and GAC (57 FR 31776 at
31809, July 17, 1992 (USEPA, 1992); USEPA, 1998b).
Field studies performed in three States using PTA demonstrated a removal efficiency of
greater than 96 percent for toluene, with initial concentrations of up to 0.6 mg/L (Ram et al.,
1990 as cited in USEPA, 1998b). Although no specific efficiency of removal by PTA was
available, xylenes have larger Henry's Law coefficients (0.22 to 0.32 atmosphere-m3/mole), as
compared to a coefficient of 0.0066 for toluene, and so would likely be removed at least as
effectively as toluene by PTA or other air stripping technologies (HSDB, 2002; 54 FR 22062 at
22105, May 22, 1989 (USEPA, 1989); USEPA, 2002b).
Performance studies employing diffused aeration, which is another air stripping
technology like PTA, to treat xylenes have demonstrated 50 to 90 percent removal efficiencies.
The study noted higher removals for VOCs that had higher Henry's Law coefficients (USEPA,
1985b as cited in USEPA, 1998a).
GAC may also be an effective treatment option for xylenes, although based on cost
estimates (54 FR 22062 at 22105, May 22, 1989 (USEPA, 1989)) it may be more than twice as
expensive as PTA for large systems on a cost per household basis. If off-gas control of PTA is
necessary, costs between PTA and GAC are more competitive, but PTA is still likely to be more
cost-effective for system sizes up to 1 to 10 million gallons per day (Adams and Clark, 1991).
Specific cost information for GAC and PTA control of xylenes is available (Adams et al., 1989;
Adams and Clark, 1991). Based on this information, EPA does not anticipate that treatment
would pose a limitation, should the Agency consider revising the current standard for xylenes.
Treatment Feasibility Review 21 June 2003
-------
VIII. Summary of Potential Research Needs Related to Treatment Feasibility
This report contains a number of suggestions for potential research that may be pursued
by EPA or by others. It incorporates information discussed in the February 2002 draft of this
report and material submitted by reviewers and commenters.
This section summarizes the potential research areas identified within the report. This is
meant to be informative to the public. It does not, however, presume a relative ranking among
them, and it is not to be considered a "static" listing, as it will be subject to further discussion
and change. Please note that EPA and stakeholder priorities on the drinking water regulatory
agenda will likely evolve; current budgets may not reflect future conditions; and, other factors
will likely impact the nature of this listing over time.
EPA is using this list as the starting point in terms of identifying research and planning
for research over long periods of time, including as information for the Agency's Comprehensive
Drinking Water Research Strategy and for other internal Agency planning tools.
Below is a listing of areas identified during the course of the Six-Year Review as
potential areas of treatment-related research. This list does not include potential research areas
related to other technical areas, such as NPDWR contaminant occurrence, analytical methods,
sampling requirements, or other matters which may be discussed in other EPA support
documents.
Investigation of treatment and water quality effects related to compliance with the
LCR and requirements under the disinfectants and disinfection byproducts
NPDWRs.
• Investigation of corrosion control chemicals, including optimization and use of
chemicals; constraints related to distribution system materials; secondary effects;
and, alternative approaches.
• Investigation of optimization of corrosion control at systems with high alkalinity
and/or hardness in source water; monitoring such as targeted monitoring to
represent copper levels; and small systems LCR issues.
Efficacy of treatment technologies in removal of specific contaminants, such as
antimony, chromium, and/or fluoride in drinking water. Specific needs may
include investigation of operational factors, waste disposal issues, treatment
effectiveness, source water quality effects, co-treatment effects, interferences
from other contaminants, secondary effects related to other NPDWRs, and POU
and POE applications.
• Oxidation and/or reduction effects on chromium species in water (EPA research
is underway).
The following is not a treatment-related research area; it has been identified by EPA as a
chemistry research need which may be of interest in relation to the common practice of drinking
water fluoridation:
• The kinetics and equilibria of chemical silicofluorides used in water fluoridation
treatment (EPA research is underway).
Treatment Feasibility Review 22 June 2003
-------
IX. References
Adams, J.Q., and R.M. Clark. 1991. Evaluating the Costs of Packed-Tower Aeration and GAC
for Controlling Selected Organics. Journal of the American Water Works Association, v. 83, n.
l,p. 132-140.
Adams, J.Q., R.M. Clark, and RJ. Miltner. 1989. Controlling Organics With GAC: A Cost and
Performance Analysis. Journal of the American Water Works Association, v. 81, n. 4, p. 49-57.
Hazardous Substances Data Bank (HSDB). 2002. Search for Toluene. Available on the Internet
through TOXNET, sponsored by the National Institute of Health's National Library of Medicine.
http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen7HSDB, accessed September 12, 2002.
Health Canada. 1986. Federal-Provincial Subcommittee on Drinking Water. Guidelines for
Canadian Drinking Water Quality - Supporting Document (Chromium). Updated September
1986. Accessed on Internet October 15, 2001:
http: //www. he- sc. gc. ca/ehp/ehd/catal ogue/b ch_pub s/dwgsup_doc/dwgsup_doc. htm
Ram, N.M., R.F. Christman, and K.P. Cantor. 1990. Significance and Treatment of Volatile
Organic Compounds in Water Supplies. Lewis Publishers, p. 363-391. (As cited in USEPA,
1998b)
United States Environmental Protection Agency (USEPA). 1977. Manual of Treatment
Techniques for Meeting the Interim Primary Drinking Water Regulations. EPA Report 600/8-
77-005. Cincinnati, OH. May 1977.
USEPA. 1985a. National Primary Drinking Water Regulations - Volatile Organic Chemicals;
Proposed Rulemaking. Federal Register. Vol. 50, No. 219. p. 46902, November 13, 1985.
USEPA. 1985b. Technologies and Costs for the Removal of Volatile Organic Chemicals from
Potable Water Supplies.
USEPA. 1986. National Primary Drinking Water Regulations; Volatile Synthetic Organic
Chemicals; Final Rule and Proposed Rule. Federal Register. Vol. 51, No. 63. p. 11396, April
2, 1986.
USEPA. 1989. National Primary and Secondary Drinking Water Regulations; Proposed Rule.
Federal Register. Vol. 54, No. 97. p. 22062, May 22, 1989.
USEPA. 1990a. Occurrence and Exposure Assessment for Chromium in Public Drinking Water
Supplies. July 24, 1990.
USEPA. 1990b. Technologies and Costs for the Removal of Phase V Synthetic Organic
Chemicals from Potable Water Supplies. Office of Drinking Water. September 1990.
USEPA. 1990c. Technologies and Costs for the Removal of Phase V Inorganic Contaminants
from Potable Water Sources. Revised Draft. January 1990.
Treatment Feasibility Review 23 June 2003
-------
USEPA. 1990d. National Primary and Secondary Drinking Water Regulations - Synthetic
Organic Chemicals and Inorganic Chemicals; Proposed Rule. Federal Register. Vol. 55, No.
143. p. 30370, July 25, 1990.
USEPA. 199la. National Primary Drinking Water Regulations - Synthetic Organic Chemicals
and Inorganic Chemicals; Monitoring for Unregulated Contaminants; National Primary Drinking
Water Regulations Implementation; National Secondary Drinking Water Regulations; Final
Rule. Federal Register. Vol. 56, No. 30. p. 3526, January 30, 1991.
USEPA. 1991b. 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?, 1991.
USEPA. 1992. National Primary Drinking Water Regulations; Synthetic Organic Chemicals
and Inorganic Chemicals; Final Rule. Federal Register. Vol. 57, No. 138. p. 31776, July 17,
1992.
USEPA. 1994. Public Water System Warning: Cyanide. Memo from William R. Diamond,
Acting Director of Drinking Water Standards Division. Office of Ground Water and Drinking
Water. March 7, 1994.
USEPA. 1998a. Cost Evaluation of Small System Compliance Options-Point-of-Use andPoint-
of-Entry Treatment Units. Draft. Standards and Risk Management Division, Office of Ground
Water and Drinking Water. Washington, DC. June 1998.
USEPA. 1998b. Small System Compliance Technology List for the Non-Microbial
Contaminants Regulated Before 1996. EPA Report 815-R-98-002. Office of Water. September
1998.
USEPA. 2000a. Geometries and Characteristics of Public Water Systems. Final Report. EPA
Report 815-R-00-024. Office of Ground Water and Drinking Water. December 2000. (As cited
in USEPA, 200Ib)
USEPA. 2000b. Arsenic Technologies and Costs for the Removal of Arsenic from Drinking
Water. EPA Report 815-R-00-028. December 2000.
USEPA. 200la. National Primary Drinking Water Regulations; Arsenic and Clarifications to
Compliance and New Source Contaminants Monitoring; Final Rule. Federal Register. Vol. 66,
No. 14. p. 6975, January 22, 2001.
USEPA. 2001b. Water Industry Drinking Water Baseline Handbook. Third Edition (Draft).
May 2001.
USEPA. 2002a. National Primary Drinking Water Regulations; Announcement of the Results
of EPA's Review of Existing Drinking Water Standards and Request for Public Comment;
Proposed Rule. Federal Register. Vol. 67, No. 74. p. 19030, April 17, 2002.
Treatment Feasibility Review 24 June 2003
-------
USEPA. 2002b. Water Treatment Technology Feasibility Support Document for Chemical
Contaminants; In Support of EPA Six-Year Review of National Primary Drinking Water
Regulations. Office of Water. EPA Report 815-D-02-001. Draft. February 2002.
USEPA. 2002c. Draft Report; Review of Literature on Removal of Fluoride From Drinking
Water. Office of Water. November 2002.
USEPA. 2002d. An Evaluation of Available Economic Information in Support of the Six-Year
Review of Existing NPDWRs. Memo from Marc Parrotta, Targeting and Analysis Branch, Office
of Ground Water and Drinking Water. March 18, 2002.
USEPA. 2003 a. Protocol for Review of Existing National Primary Drinking Water Regulations.
EPA Report 815-R-03-002. Final. June 2003.
USEPA. 2003b. Occurrence Estimation Methodology and Occurrence Findings Report for Six-
Year Review of National Primary Drinking Water Regulations. EPA Report 815 -R-03 -006.
Final. June 2003.
USEPA. 2003 c. Analytical Feasibility Support Document for the Six-Year Review of Existing
National Primary Drinking Water Regulations. EPA Report 815-R-03-003. Final. March 2003.
USEPA. 2003d. Public Comment and Response Summary for the Six-Year Review of National
Primary Drinking Water Regulations. EPA Report 815-R-03-001. Final. June 2003.
Treatment Feasibility Review 25 June 2003
-------
Treatment Feasibility Review 26 June 2003
-------
-------
EPA 815-R-03-004
Water Treatment Technology Feasibility Support Document for Chemical Contaminants;
In Support of EPA Six-Year Review of National Primary Drinking Water Regulations
------- |