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Proven Alternatives for
Aboveground Treatment of Arsenic
in Groundwater
ENGINEERING FORUM ISSUE PAPER
Section
Summary
Precipitation/C
Adsorption
Ion Exchange . .
^precipitation
Membrane Filtration
Appendix A -
Appendix B -
Appendix C -
Appendix D -
Appendix E -
Precipitation/Coprecipitation
Performance Data
Page
1
. 17
. 24
. 30
35
Adsorption Performance Data
Ion Exchange Performance Data
Membrane Filtration Performance
Data
Selected Annotated Bibliography
1.0 SUMMARY
1.1 Abstract
This issue paper identifies and summarizes experiences
with proven aboveground treatment alternatives for
arsenic in groundwater, and provides information on
their relative effectiveness and cost. The information
contained in this paper can also be found in the report
"Arsenic Treatment Technologies for Soil, Waste, and
f^ater ",EPA542-R-02-004(Ref. 1.12), which provides
cost and performance data for additional technologies
that can treat arsenic in soil, waste, and water. This
paper has been developed jointly by EPA's Engineering
Forum and Technology Innovation Office. EPA's
Engineering Forum is a group of professionals,
representing EPA Regional Offices, who are committed
to identifying and resolving the engineering issues
related to remediation of Superfund and hazardous
waste sites. The Forum is sponsored by the Technical
Support Project.
In January 2001, EPA published a revised maximum
contaminant level (MCL) for arsenic in drinking water
that requires public water suppliers to maintain arsenic
concentrations at or below 0.010 milligrams per liter
(mg/L) by 2006 (Ref. 1.1,1.9). The revised standard may
affect arsenic cleanup goals for groundwater.
The information contained in this issue paper can help
managers at sites with arsenic-contaminated
groundwater to:
Identify proven and effective treatment technologies
Screen those technologies based on effectiveness,
treatment goals, site characteristics, and cost
Apply technology and experience from sites with
similar remediation challenges
Find more detailed arsenic treatment information
using this issue paper as a reference
Arsenic is a component of many industrial raw
materials, products, and wastes, and is a contaminant of
concern in groundwater at many remediation sites.
Because arsenic readily changes valence state and
reacts to form species with varying toxicity and
mobility, effective treatment of arsenic can be
challenging. Treatment can result in residuals that,
under some environmental conditions, have unstable
toxicity and mobility. In addition, the revised MCL for
arsenic in drinking water could result in lower treatment
goals for aboveground treatment systems. A lower
treatment goal may significantly affect the selection,
design, and operation of arsenic treatment systems.
This paper is a revision of the June 2002 version,
and contains additional data identified for the
related report "Arsenic Treatment Technologies for
Soil, Waste, and Water" (EPA-542-R-02-004), which
can be downloaded from http://clu-in.org/arsenic.
Solid Waste and Emergency
Response (5102G)
EPA-542-S-02-002
October 2002 (Revised)
www.epa.gov/tio/tsp
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1.2 Background
Arsenic Occurrence
Arsenic occurs naturally in rocks, soil, water, air, plants,
and animals. Natural activities such as volcanic action,
erosion of rocks, and forest fires can release arsenic into
the environment. Industrial products containing arsenic
include wood preservatives, paints, dyes, metals,
Pharmaceuticals, pesticides, herbicides, soaps, and
semiconductors. Man-made sources of arsenic in the
environment include mining and smelting operations;
agricultural applications; and the use of industrial
products and disposal of wastes containing arsenic (Ref.
1.1).
Source: (Ref. 1.3)
Figure 1.1
The Five Most Common Contaminants of Concern at
Superfund Sites
Lead Arsenic Benzene Chromium Toluene
Based on information from EPA's CERCLIS 3 database
through fiscal year (FY) 1999 (Ref. 1.3), arsenic is the
second most common contaminant of concern (COC)
cited in Records of Decision (RODs) for sites on the
Superfund National Priorities List (NPL) (Figure 1.1).
Arsenic is a COC at 568 sites or 47% of the 1,209 sites
on the NPL for which a ROD has been signed (Ref. 1.3,
1.8). Table 1.1 lists by media the number of Superfund
sites with arsenic as a COC. Arsenic is a COC for
groundwater at 380 sites, or 31% of the 1,209 sites on
the NPL for which a ROD has been signed.
Arsenic Chemistry
Arsenic is a metalloid or inorganic semiconductor. It
occurs with valence states of -3, 0, +3 (arsenite,
As[III]), and +5 (arsenate, As[V]). Because the valence
states -3 and 0 occur rarely, this discussion of arsenic
chemistry focuses on As(III) and As(V). Arsenic forms
inorganic and organic compounds. Inorganic
compounds of arsenic include hydrides (e.g., arsine),
halides, oxides, acids, and sulfides (Ref. 1.4).
The toxicity and mobility of arsenic varies with its
valence state and chemical form. As(III) is generally
more toxic to humans and four to ten times more
soluble in water than As(V) (Ref. 1.2, 1.6). However,
different chemical compounds containing arsenic
exhibit varying degrees of toxicity and solubility.
Table 1.1
Superfund Sites with Arsenic as a Contaminant of
Concern by Media3
1 Media
Groundwater
Soil
Sediment
Surface Water
Debris
Sludge
Solid Waste
Leachate
Liquid Waste
Air
Residuals
Other
Number of Sites
380
372
154
86
77
45
30
24
12
8
1
21
The total number of sites in Table 1.1 exceeds the
total number of sites with arsenic contamination (568,
Figure 1.1) because some sites have more than one
type of media contaminated with arsenic.
Source: (Ref. 1.3)
Arsenic can change its valence state and chemical form
in the environment. Some conditions that could affect
arsenic valence and speciation include (Ref. 1.7):
pH
Oxidation-reduction potential
The presence of complexing ions, such as ions of
sulfur, iron, and calcium
Microbial activity
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Adsorption-desorption reactions can also affect the
mobility of arsenic in the environment. Clays,
carbonaceous materials, and oxides of iron, aluminum,
and manganese are soil components that can participate
in adsorptive reactions with arsenic (Ref 1.7).
Revised MCL for Arsenic
In January 2001, EPA published a revised MCL for
arsenic in drinking water that requires public water
suppliers to maintain arsenic concentrations at or below
0.010 mg/L by 2006 (Ref. 1.1,1.9). The former MCL was
0.050 mg/L. Treatment goals for arsenic at groundwater
remediation sites can be based on MCLs, background
contaminant levels, or risk.
Lower treatment goals for arsenic present multiple
technical challenges for the aboveground treatment of
groundwater, and will likely result in higher treatment
costs. Some sites that might not have needed
groundwater treatment to remove arsenic under the
former MCL of 0.050 mg/L may need to treat
groundwater for arsenic to meet the revised MCL of
0.010 mg/L. At some sites, the plume of groundwater
containing arsenic at concentrations greater than 0.010
mg/L could be significantly larger in volume and areal
extent than the plume containing arsenic at greater than
0.050 mg/L. Site-specific conditions will determine if
new arsenic treatment systems need to be designed, or
if existing systems need to be retrofitted to treat the
larger volumes. In addition, treatment of groundwater
to lower arsenic concentrations can sometimes require
the use of multiple technologies in sequence. For
example, a site with an existing metals precipitation/
coprecipitation system may need to add another
technology such as ion exchange to achieve a lower
treatment goal.
In some cases, a lower treatment goal might be met by
changing the operating parameters of existing systems.
For example, changing the type or amount of treatment
chemicals used, replacing spent treatment media more
frequently, or changing treatment system flow rates can
reduce arsenic concentrations in the treatment system
effluent. However, such changes may increase
operating costs from use of additional treatment
chemicals or media, use of more expensive treatment
chemicals or media, and from disposal of increased
volumes of treatment residuals. Technology-specific
factors that might affect costs for retrofitted systems are
discussed in the individual technology summary
sections (see Sections 2.0 through 5.0) of this issue
paper.
Additional information and guidance on retrofitting and
optimizing the performance of aboveground treatment
systems for groundwater is available from the Federal
Remediation Technologies Roundtable Remedial
Process Optimization/Remedial System Evaluation web
page at http://www.frtr.gov/remedopt.htm. This
website contains technology-specific guidance on
optimization of aboveground treatment systems for
groundwater.
Technologies and Media Addressed
This issue paper focuses on the application of
treatment technologies to the aboveground removal of
arsenic from groundwater. Information on the below-
ground (in situ) treatment of arsenic-contaminated
groundwater is not presented; for more information on
in situ treatment of groundwater, refer to the related
report "Arsenic Treatment Technologies for Soil,
Waste, and Water" (Ref. 1.12), and EPA's web site,
including http://clu-in.org. The following ex situ
technologies are addressed in this issue paper:
Precipitation/coprecipitation (Section 2.0)
Adsorption (Section 3.0)
Ion exchange (Section 4.0)
Membrane filtration (Section 5.0)
These technologies are included because they have
been used at full scale to remove arsenic from water.
Each of these technologies can include more than one
type of treatment system. For example, membrane
filtration includes nanofiltration and reverse osmosis
treatment systems, both of which have been used to
treat arsenic. Although nanofiltration and reverse
osmosis are sometimes discussed as distinct
technologies in technical literature, this issue paper
discusses them as a single technology because of their
similarity in design, operation, and application to
arsenic treatment. The specific treatment types
included under each technology are described in the
technology-specific discussions in Sections 2.0
through 5.0.
-------
Oxidation of As(III) to As(V) can improve the
performance of the technologies this issue paper
focuses on. Chlorine, potassium permanganate,
aeration, peroxide, ozone, and photo-oxidation have
been used to convert As(III) to As(V) (Ref 1.12). Many
arsenic treatment systems use oxidation as a
pretreatment step to improve performance. In addition,
some of the technologies include oxidation as an
intrinsic part of their application. For example,
greensand filtration, which is listed as an adsorption
technology in this issue paper, includes oxidation and
adsorption of arsenic in one unit operation. Although
oxidation can either be a pretreatment step or an
intrinsic part of another technology, it is not typically
used alone as an arsenic treatment. Therefore, this
issue paper does not contain a separate section on
oxidation.
This issue paper does not address three technologies
that have been used to treat water containing arsenic:
Biological treatment
Phytoremediation
Electrokinetics
Biological treatment is not addressed because it does
not appear to be used for the aboveground treatment of
groundwater containing arsenic. The information
sources used for this issue paper contained only a
limited number of bench- or pilot-scale projects on
biological treatment of arsenic in water, and no
aboveground treatments of groundwater conducted at
full scale were found. Phytoremediation and
electrokinetics are not addressed because these
technologies are applied in situ. Data available on
these three technologies are discussed in the related
report "Arsenic Treatment Technologies for Soil,
Waste, and Water" (Ref'. 1.12).
This issue paper presents and analyzes information
about the aboveground removal of arsenic from
groundwater, drinking water, industrial wastewater,
surface water, mine drainage, and leachate collectively
referred to as "water" throughout the remainder of this
paper. In some cases, the technologies used to treat
one type of water are not applicable to another type of
water due to different wastewater characteristics or
post-treatment water use. For example, the technology
used to treat industrial wastewater containing high
arsenic concentrations that is discharged after treatment
may not be appropriate to treat drinking water.
However, arsenic in drinking water, industrial
wastewater, surface water, mine drainage, and leachate
is often removed using the same technologies as those
used to treat groundwater. Information about such
treatment technologies can help remedial project
managers (RPMs) make an informed decision about the
selection, design, and operation of aboveground
treatment of arsenic-contaminated groundwater.
Treatment Trains
Treatment trains consist of two or more technologies
used together, either integrated into a single process or
operated as a series of treatment technologies. The
technologies in a treatment train may treat the same
contaminant. For example, at one site a treatment train
of reverse osmosis followed by ion exchange was used
to remove arsenic from surface water (Ref. 1.16). A
common treatment train used for arsenic-contaminated
water includes an oxidation step to change arsenic from
As(III) to its less soluble As(V) state, followed by
precipitation/coprecipitation and filtration to remove the
precipitate.
Some treatment trains are used when no single
technology is capable of treating all contaminants in a
particular medium. For example, at the Saunders Supply
Company Superfund Site in Virginia (Appendix A,
Project 18), an aboveground system consisting of
metals precipitation, filtration, and activated carbon
adsorption was used to treat groundwater contaminated
with arsenic and pentachlorophenol (PCP). In this
treatment train the precipitation and filtration processes
were used for treating arsenic and the activated carbon
adsorption process was used to treat PCP.
In many cases, the available information on the use of
treatment trains did not specify the technologies within
the train that were intended to treat arsenic. Where
influent and effluent arsenic concentrations were
available, often they were available only for the entire
treatment train, and not the individual components. In
such cases, engineering judgement was used to identify
the technology for treating arsenic. For example, at the
Higgins Farm Superfund Site in New Jersey (Appendix
A, Project 17), a treatment train consisting of air
stripping, metals precipitation, filtration, and ion
exchange was used to treat groundwater contaminated
with arsenic, nonhalogenated volatile organic
compounds (VOCs) and halogenated VOCs. The
precipitation, filtration, and ion exchange processes
-------
were assumed to remove arsenic from the wastewater,
while the air stripping process was assumed to treat the
VOCs but have only a negligible effect on the arsenic
concentration.
Where treatment trains included more than one
potential arsenic treatment technology, all arsenic
treatment technologies were assumed to contribute to
arsenic treatment, unless available information indicated
otherwise. For example, at the Higgins Farm Superfund
site, arsenic-contaminated groundwater was treated
with precipitation and ion exchange. It was assumed
that both technologies contributed to the reduction in
concentration of the arsenic. Information about this
treatment is presented in both the precipitation/
coprecipitation (Section 2.0) and ion exchange (Section
4.0) technology sections.
Information Sources
This issue paper was prepared in conjunction with the
report "Arsenic Treatment Technologies for Soil,
Waste, and Water" (Ref 1.12). That report contains
detailed treatment information for 13 treatment
technologies applicable to aqueous or nonaqueous
media. This issue paper is based on information
contained in that report.
The report "Arsenic Treatment Technologies for Soil,
Waste, and Water" (Ref. 1.12) contains information
gathered from the following sources:
A comprehensive literature search
Documents and databases prepared by EPA, the U.S.
Department of Defense (DoD), and the U.S.
Department of Energy (DOE)
Information supplied by users (for example, RPMs)
and vendors of treatment technologies
Internet sites
The report "Arsenic Treatment Technologies for Soil,
Waste, and Water" (Ref. 1.12) contains a detailed
discussion of the data collection process and the data
collected.
arsenic-contaminated water, and is capable of treating a
wide range of influent concentrations to the revised
MCL for arsenic. The effectiveness of this technology
is less likely to be reduced by characteristics and
contaminants other than arsenic, compared to other
water treatment technologies. It is also capable of
treating water characteristics or contaminants other
than arsenic, such as hardness or heavy metals.
Systems using this technology generally require skilled
operators; therefore, precipitation/coprecipitation is
more cost effective at a large scale where labor costs
can be spread over a larger amount of treated water
produced.
The effectiveness of adsorption and ion exchange for
arsenic treatment is more likely than precipitation/
coprecipitation to be affected by characteristics and
contaminants other than arsenic. However, these
technologies are capable of treating arsenic to the
revised MCL. Small capacity systems using these
technologies tend to have lower operating and
maintenance costs, and require less operator expertise.
Adsorption and ion exchange tend to be used more
often when arsenic is the only contaminant to be
treated, for relatively smaller systems, and as a
polishing technology for the effluent from larger
systems. Membrane filtration is used less frequently
because it tends to have higher costs and produce a
larger volume of residuals than other arsenic treatment
technologies.
The revised MCL may require that existing membrane
filtration, adsorption, and ion exchange systems be
modified to help reduce arsenic concentrations in the
effluent. Examples of such modifications include
addition of an adsorption media bed, more frequent
regeneration or replacement of ion exchange media, or
use of a membrane with a smaller molecular weight cut-
off. However, these modifications could increase the
treatment costs. Membrane filtration, adsorption, and
ion exchange can also be added as part of a treatment
train to increase the effectiveness of treatment. This
also would result in an increase in the overall treatment
costs.
1.3 Summary of Key Findings
Arsenic Treatment Technology Performance
Based on the information gathered for this paper,
precipitation/coprecipitation is frequently used to treat
Point-of-use systems most commonly used for drinking
water include adsorption (activated alumina) and
membrane filtration (reverse osmosis) (Ref. 1.13). In
addition, some simple, low-cost precipitation/
coprecipitation point-of-use systems have been
-------
developed for use in developing countries to remove
arsenic from drinking water (Ref 1.22).
Table 1.2 summarizes the number of full-scale treatment
processes identified for this paper. Data are available
on applications used to treat ground-water and other
aqueous media such as surface water, industrial
wastewater, and leachate. Full-scale projects include
those used to:
Remediate an entire area of contamination; for
example, a technology used to treat an entire
groundwater plume,
Remove arsenic from drinking water by a publicly-
owned or commercial facility
Commercially treat as-generated wastewaters
Table 1.2
Full-Scale, Aboveground Treatments of Arsenic
Identified for this Paper
Technology
Precipitation/
coprecipitation
Adsorption
Ion Exchange
Membrane
Filtration
Media
Groundwater
16
7
3
1
Other Aqueous
Media
29
8
4
1
Source: (Ref. 1.12)
Table 1.3 summarizes the performance data gathered on
the treatment of arsenic in water (Tables 1.3 through 1.6
are provided after the list of references). The table also
provides information on the number of projects that
achieved less than 0.050 or 0.010 mg/L of arsenic in
treatment effluent. The table is limited to technology
applications for which both pretreatment and post-
treatment data are available.
Table 1.3 and the sections summarizing performance
data discuss the number of projects identified in the
data sources that reduced arsenic concentrations to
below 0.050 mg/L and 0.010 mg/L respectively. Data on
projects that did not meet these treatment goals do not
necessarily indicate that the technology is not capable
of meeting these goals. In many cases, the remediation
project goal may have been to meet the former arsenic
MCL of 0.050 mg/L, or a goal based on background
levels or risk. Treatment goals for industrial
wastewaters may vary depending on the particular
industrial wastewater effluent guidelines or other
regulations applicable to that industry. Information on
site-specific treatment goals generally was not available
in the references used to prepare this issue paper.
Table 1.4 at the end of this section is a screening matrix
for arsenic treatment technologies. It can assist
decision makers in evaluating candidate cleanup
technologies by providing information on each
technology's relative availability, cost, and other
factors. The matrix is based on the Federal Remediation
Technologies Roundtable Technology (FRTR)
Treatment Technologies Screening Matrix (Ref. 1.23),
but has been tailored to aboveground treatment
technologies for arsenic in water, based on information
in this issue paper. Table 1.4 differs from the FRTR
matrix by:
Limiting the scope of the table to the technologies
discussed in this issue paper.
Changing the information based on the narrow scope
of this issue paper. For example, the FRTR screening
matrix lists the overall cost of precipitation as
"average" (circle symbol) in comparison to other
treatment technologies for surface water,
groundwater, and leachate. However, in comparison
to the other technologies discussed in this issue
paper, precipitation/coprecipitation costs are typically
lower.
Adding information about specific water
characteristics that can affect technology
performance.
Table 1.4 includes the following information:
Development Status - The scale at which the
technology has been applied. "F" indicates that the
technology has been applied to a site at full scale.
All of the technologies have been applied at full
scale.
Typically Requires Pretreatment - Whether the
technology is typically preceded by another
technology. Adsorption, ion exchange, and
membrane filtration typically require pretreatment
because the equipment is susceptible to fouling from
suspended solids and organics.
-------
Residuals Produced - The residuals typically
produced that require additional management. "S"
indicates that a solid residual is produced while "L"
indicates that a liquid residual is produced.
Precipitation/coprecipitation typically generates a
sludge, which is considered a solid residual.
Although this sludge may be dewatered, generating a
liquid, the liquid is typically fed back to the
precipitation/coprecipitation process rather than
being disposed. Adsorption and ion exchange
generate spent regenerating solution and solid spent
media. Membrane filtration generates a liquid reject
stream.
O&Mor Capital Intensive - This indicates the main
cost-intensive parts of the system. Operation and
maintenance ("O&M") indicates that the operation
and maintenance costs tend to be high in comparison
to other technologies. "Cap" indicates that capital
costs tend to be high in comparison to other
technologies. Because of the limited cost information
available for arsenic treatment, the cost ratings from
the FRTR Screening Matrix were used without
tailoring them to arsenic treatment.
Availability - The relative number of vendors that
can design, construct, or maintain the technology. A
square indicates more than four vendors. All
technologies are available from more than four
vendors.
Reliability/Maintainability - The expected
reliability/maintainability of the technology. A
square indicates high reliability and low maintenance
and a circle, average reliability and maintenance.
Precipitation/coprecipitation is rated as more reliable
and maintainable because it is less susceptible to
upset or interference from varying influent water
characteristics such as organics and suspended
solids.
Overall Cost- Design, construction, and O&M costs
of the core process that defines each technology,
plus the treatment of residuals. It does not include
mobilization, demobilization, and pre- and
post-treatment costs. A square indicates lower
overall cost, a circle average overall cost, and a
triangle higher overall cost. Reverse osmosis
(membrane filtration) is considered higher cost
because it generally is more expensive and generates
larger volumes of treatment residuals than other
arsenic treatment technologies (Ref. 1.13).
Untreated Water Characteristics That May Require
Pretreatment or Affect Performance and Cost- The
types of contaminants or other substances that
generally may interfere with arsenic treatment for
each technology. A"* " indicates that the presence
of the characteristic may significantly interfere with
technology effectiveness. Although these
contaminants can usually be removed before arsenic
treatment through pretreatment with another
technology, the addition of a pretreatment
technology may increase overall treatment costs and
generate additional residuals requiring disposal.
The selection of a treatment technology for a particular
site will depend on many site-specific factors; thus the
matrix is not intended to be used as the sole basis for
remediation decisions.
Arsenic Treatment Costs
This issue paper discusses two types of information on
the cost of arsenic treatment technologies:
1. Information on the cost of aboveground treatment
for groundwater containing arsenic or chromium at
Superfund sites
2. Information on the cost of treating drinking water
to remove arsenic
A limited amount of cost data on arsenic treatment was
identified for this paper. In many cases, the cost
information is incomplete. For example, some data are
for O&M costs only, and do not specify the associated
capital costs. In other cases, a cost per unit of water
treated is provided, but total costs are not. For some
technologies, no arsenic-specific cost data were
identified.
In many cases, available cost information is for an entire
treatment train that includes technologies intended to
treat contaminants other than arsenic. Information was
available on only two systems used to treat only
arsenic. The technologies used to treat arsenic are also
often used to treat other inorganic contaminants, such
as chromium. The cost of eight systems used to treat
only chromium was also available to supplement
arsenic-specific costs. Table 1.5 lists cost information
for 10 aboveground systems used to treat arsenic or
chromium in groundwater at Superfund sites. The
treatment systems at these sites were intended to treat
only arsenic or chromium and consist of a single
treatment technology with associated pre- or post-
treatment technologies, such as post-treatment filtration
-------
to remove solids from precipitation/coprecipitation
processes.
The cost data were taken from a variety of sources,
including EPA, DoD, other government sources, and
information from technology vendors. The quality of
these data varied, with some sources providing detailed
information about the items included in the costs, while
other sources gave little detail about their basis. In
most cases, the particular year for the costs were not
provided. The costs presented throughout this paper
are the costs reported in the identified references, and
are not adjusted for inflation. Because of the variation
in type of information and quality, this paper does not
provide a summary or interpretation of the costs
presented.
The EPA document "Technologies and Costs for
Removal of Arsenic From Drinking Water" (Ref 1.13)
contains more information on the cost to reduce the
concentration of arsenic in drinking water from the
former MCL of 0.050 mg/L to below the revised MCL of
0.010 mg/L. The document includes capital and O&M
cost curves for a variety of processes, including:
Retrofitting of existing precipitation/coprecipitation
processes to improve arsenic removal (enhanced
coagulation/filtration and enhanced lime softening)
Precipitation/coprecipitation followed by membrane
filtration (coagulation-assisted micro filtration)
Ion exchange (anion exchange) with varying levels of
sulfate in the influent
Two types of adsorption (activated alumina at
varying influent pH and greensand filtration)
Oxidation pretreatment technologies (chlorination
and potassium permanganate)
Treatment and disposal costs of treatment residuals
(including mechanical and non-mechanical sludge
dewatering)
Point-of-use systems using adsorption (activated
alumina) and membrane filtration (reverse osmosis)
The EPA cost curves are based on computer cost
models for drinking water treatment systems. Costs for
full-scale reverse osmosis, a common type of membrane
filtration, were not included because it generally is more
expensive and generates larger volumes of treatment
residuals than other arsenic treatment technologies
(Ref. 1.13). Although the cost information is only for
the removal of arsenic from drinking water, many of the
same treatment technologies can be used for
aboveground treatment of groundwater and have
similar costs.
Table 1.6 presents estimated capital and annual O&M
costs for four treatment technologies based on cost
curves presented in "Technologies and Costs for
Removal of Arsenic From Drinking Water"'.
1. Precipitation/coprecipitation followed by membrane
filtration (coagulation-assisted micro filtration)
2. Adsorption (greensand filtration)
3. Adsorption (activated alumina with pH of 7 to 8 in
the influent)
4. Ion exchange (anion exchange with <20 mg/L
sulfate in the influent)
The table presents the estimated costs for three
treatment system sizes: 0.01, 0.1, and 1 million gallons
per day (mgd). The costs presented in Table 1.6 are for
specific technologies listed in the table, and do not
include costs for oxidation pretreatment or management
of treatment residuals. Detailed descriptions of the
assumptions used to generate the arsenic treatment
technology cost curves are available (Ref. 1.13).
Table 1.7 presents the capital and O&M costs for
activated alumina and reverse osmosis point-of-use
treatment systems serving a single household, based
on available cost curves (Ref. 1.13). The costs
presented assume that only water used for drinking and
cooking will be treated, at a rate of 3 gallons per day
(gpd).
Table 1.7
Estimated Cost3 of Point-of-Use Drinking Water
Treatment Systems (3 Gallons per Day)
Technology
Adsorption
(activated alumina)
Membrane filtration
(reverse osmosis)
Capital
Cost (S)
297
865
O&M Cost
(S/year)
413
267
a Costs are rounded to three significant figures.
O&M = operation and maintenance
Source: (Ref. 1.13)
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Organization of Paper
Sections 2.0 through 5.0 of this issue paper contain
additional details on each of the four arsenic treatment
technologies used for aboveground treatment:
A brief summary
Technology description and principles
A figure depicting a model of the technology
Type, number, and scale of identified projects for
aboveground treatment
Summary of performance data
Advantages and potential limitations
Summary of cost data
Considerations for retrofitting existing systems
Appendices A through D contain tables showing more
information on the arsenic treatment projects found in
the sources used for this issue paper.
References
1.1 U.S. EPA. Fact Sheet: Drinking Water Standard for
Arsenic. Office of Water. EPA 815-F-00-015.
January 2001.
http://www.epa.gov/safewater/ars/
ars_rule_factsheet.html.
1.2 U.S. Occupational Safety and Health
Administration. Occupational Safety and Health
Guidelines for Arsenic, Organic Compounds (as
As). November, 2001.
http: //www. o sha-slc. go v/SLTC/healthguidelines/
arsenic/recognition.html.
1.3 U.S. EPA. Office of Emergency and Remedial
Response. Comprehensive Environmental
Response Compensation and Liability Information
System database (CERCLIS 3). October 2001.
1.4 Kirk-Othmer. "Arsenic and Arsenic Alloys." The
Kirk-Othemer Encyclopedia of Chemical
Technology, Volume 3. John Wiley and Sons,
New York. 1992.
1.5 Kirk-Othmer. "Arsenic Compounds" The Kirk-
Othemer Encyclopedia of Chemical Technology,
VolumeS. John Wiley and Sons, New York. 1992.
1.6 U.S. EPA. Treatment Technology Performance
and Cost Data for Remediation of Wood
Preserving Sites. Office of Research and
Development. EPA-625-R-97-009. October 1997.
http: //epa. gov/ncepihom.
1.7 Vance, David B. "Arsenic - Chemical Behavior
and Treatment". October, 2001.
http://2the4.net/arsenicart.htm.
1.8 U.S. EPA. Treatment Technologies for Site
Cleanup: Annual Status Report (Tenth Edition).
Office of Solid Waste and Emergency Response.
EPA-542-R-01-004. February 2001. http://clu-
in.org.
1.9 U.S. EPA. National Primary Drinking Water
Regulations; Arsenic and Clarifications to
Compliance and New Source Contaminants
Monitoring; Proposed Rule. Federal Register, Vol
65, Number 121, p. 38888. June 22, 2000.
http://www.epa.gov/safewater/ars/arsenic.pdf
1.10 U.S. EPA Office of Water. Fact Sheet: EPA to
Implement lOppb Standard for Arsenic in Drinking
Water. EPA 815-F-01-010. October, 2001.
http://www.epa.gov/safewater/ars/
ars-oct-factsheet.html.
1.11 Federal Register. Land Disposal Restrictions:
Advanced Notice of Proposed Rulemaking.
Volume 65, Number 118. June 19, 2000. pp.37944-
37946.
http://www.epa.gov/fedrgstr/EPA-WASTE/2000/
June/Day-19/f 15 3 92 .htm
1.12 U.S. EPA. Office of Solid Waste and Emergency
Response. Arsenic Treatment Technologies for
Soil, Waste, and Water. EPA 542-R-02-004. June
2002.
1.13 U.S. EPA. Office of Water. Technologies and
Costs for Removal of Arsenic From Drinking
Water. EPA-R-00-028. December 2000.
http://www.epa.gov/safewater/ars/
treatments_and_co sts. pdf
1.14 U.S. EPA. Cost and Performance Report. Pump
and Treat of Contaminated Groundwater at the
Baird and McGuire Superfund Site, Holbrook,
Massachusetts. Federal Remediation
Technologies Roundtable. September 1998.
http://www.frtr.gov/costperf.htm.
1.15 U.S. EPA. Cost and Performance Report. Pump
and Treat of Contaminated Groundwater at the
Mid-South Wood Products Superfund Site, Mena,
Arkansas. Federal Remediation Technologies
Roundtable. September 1998.
http://www.frtr.gov/costperf.htm.
1.16 U.S. EPA. Office of Research and Development.
Arsenic & Mercury - Workshop on Removal,
Recovery, Treatment, and Disposal. EPA-600-R-
92-105. August 1992.
-------
1.17 U.S. EPA. Cost Analyses for Selected
Ground-water Cleanup Projects: Pump and Treat
Systems and Permeable Reactive Barriers, EPA-
542-R-00-013, February 2001. http://clu-in.org.
1.18 U.S. EPA. Office of Solid Waste and Emergency
Response. Groundwater Pump and Treat
Systems: Summary of Selected Cost and
Performance Information at Superfund-Financed
Sites. EPA-542-R-01-021b. December 2001.
http://clu-in.org.
1.19 The Agency for Toxic Substances and Disease
Registry (ATSDR): ToxFAQs for Arsenic (12).
July, 2001. http://www.atsdr.cdc.gov/tfacts2.html.
1.20 U.S. EPA. Office of Water. Arsenic in Drinking
Water Rule Economic Analysis. EPA-815-R-00-
026. December 2000.
http://www.epa.gov/safewater/ars/
econ_analysis.pdf
1.21 Murcott, Susan. Appropriate Remediation
Technologies for Arsenic-Contaminated Wells in
Bangladesh. June 28,2001.
http: //phy s4 .harvard. edu/~wilson/murcott. html.
1.22 E-mail attachment sent from Anni Loughlin of U.S.
EPA Region I to Linda Fiedler, U.S. EPA. August
21,2001.
1.23 Federal Remediation Technologies Reference
Guide and Screening Manual, Version 4.0. Federal
Remediation Technologies Roundtable.
September 5,2001.
http://www.frtr.gov/matrix2/top _page.html.
10
-------
Table 1.3
Summary of Performance Data for Treatment of Arsenic in Water
Technology
Precipitation/Coprecipitation
Adsorption
Ion Exchange
Membrane Filtration
Number of Applications
Identified3 (Number with
Performance Data)
Bench
Scale
NC
NC
NC
6(0)
Pilot
Scale
24 (22)
8(5)
0
25(2)
Full
Scale
45 (30)
15(9)
7(4)
2(2)
Total Number of
Applications Identified
(Number with
Performance Data)
69 (52)
23(14)
7(4)
33(4)
Number of Applications
Achieving <0.050 mg/L
Arsenic
35
12
3
4
Number of Applications
Achieving <0.010 mg/L
Arsenic
19
7
2
2
a Applications were identified through a search of available technical literature. The number of applications include only those identified during the
preparation of this paper, and are not comprehensive.
NC = Data not collected
Source: Adapted from data in Sections 2.0 to 5.0 of this issue paper
11
-------
Table 1.4
Arsenic Treatment Technologies Screening Matrix
Rating Codes
- Better;
v ^ - Average;
' ' - Worse;
Y - Yes; N - No.
F - Full; P - Pilot.
S - Solid; L - Liquid; V - Vapor.
Cap - Capital; N - Neither; O&M
- Operation & Maintenance.
- May require pretreatment or
affect cost and performance.
H
1
5
E
O.
Q
Q
f
g
1
.S "sn
H Jg
*- O
C to
ll
Q "3
E^ - '
^
3
OH
3
Q
|
"c
3
'S.
O
o
S
§
S
1
1
C
cti
i
£
3
1
|
"tc
"S
O
U
13
0
Characteristics That May Require Pretreatment or Affect Performance or
Cost
c
o
"c
c
o
U
c
^
DJD
S
g
1
1
6
i
1
a
Q.
Technology
Precipitation/Coprecipitation
Adsorption
F
F
Y
Y
S
S,L
Cap
&
O&M
Cap
&
O&M
|
H
H
0
0
.
.
'
Other Characteristics
Presence of other compounds
Type of chemical addition
Chemical dosage
Treatment goal
Sludge disposal
Flow rate
pH
Fouling
Contamination concentration
Spent media
-------
Rating Codes
- Better;
v ^ - Average;
' ' - Worse;
Y - Yes; N - No.
F - Full; P - Pilot.
S - Solid; L - Liquid; V - Vapor.
Cap - Capital; N - Neither; O&M
- Operation & Maintenance.
- May require pretreatment or
affect cost and performance.
Ion Exchange
Membrane Filtration
3
X
0
e
Q.
1
F
F
f
1
c "^
1 a
H §i
*- o
S %
11
Q fj
E^ - '
Y
Y
1
O
O
OH
O
I
S,L
L
*33
C
"c
"5,
U
o
S
§
Cap
&
O&M
Cap
&
O&M
1"
"«
1
H
1
«
"3
-M1
3
1
|
tc
O
O
I
0
O
"«
Q
O
A
Characteristics That May Require Pretreatment or Affect Performance or
Cost
c
o
"c
c
o
U
'5
Q
j
DJD
S
1
T3
|
U
u
1
a
Q.
'
'
Other Characteristics
Presence of competing ions
Presence of organics
Presence of trivalent ion
Project scale
Bed regeneration
Sulfate
Suspended solids, high molecular weight,
dissolved solids, organic compounds and
colloids
Temperature
Type of membrane filtration
Initial waste stream
Rejected waste stream
Source: Adapted from the Federal Remediation Technologies Roundtable Technology Screening Matrix, http://www.frtr.gov. September 2001. (Ref 1.23)
a Relative costs for precipitation/coprecipitation, adsorption, and ion exchange are sensitive to treatment system capacity, untreated water characteristics, and
other factors.
13
-------
Table 1.5
Available Data on the Cost3 for Aboveground Treatment of Arsenic and Chromium in Groundwater at Superfund Sites
Site Name
and State
Precipitation/Co]
Vineland
Chemical
Company, NJ
Winthrop
Landfill, NJ
Better Brite
Plating, WI
Odessa I, TX
Odessa II, TX
Selma
Treating
Company, CA
United
Chrome, OR
Contaminant1"
Treatment
Technology0
Years in
Operation
Capital
Costs
(S
Million)
Annual
O&M
Costs
(S
Million)
Average
Annual O&M
Costs (S)Per
Thousand
Gallons
Treated
Estimated
Treatment
Rate
(gpm)
Remedial
Project
Manager and
Telephone
Number
Reference
3recipitation
As
As
Cr
Cr
Cr
Cr
Cr
Precipitation/
coprecipitation
Precipitation/
coprecipitation
Precipitation/
coprecipitation
Precipitation/
coprecipitation
Precipitation/
coprecipitation
Precipitation/
coprecipitation
Precipitation/
coprecipitation
0.6
6
5.6
4.2
4.1
3.2
8.6
_
$2
$1.9
$1.8
_
$5.1
$4
$0.25
$0.036
$0.22
($0.5)e
$0.16
$0.3
$0.11
_
_
$7.5
$5.4
_
$15
1,400
65
60
-
150
Matthew
Westgate
212-637-4422
Anni
Loughlin,
617-918-1273
John Peterson
312-353-1264
Ernest Franke
214-665-8521
Ernest Franke
214-665-8521
Michelle Lau
415-744-2227
Al Goodman
503-326-3685
1.18
1.22
1.18
1.17,1.18
1.17
1.18
1.17
14
-------
Table 1.5
Available Data on the Cost3 for Aboveground Treatment of Arsenic and Chromium in Groundwater at Superfund Sites (continued)
Site Name
and State
Contaminant1"
Treatment
Technology0
Years in
Operation
Capital
Costs
(S
Million)
Annual
O&M
Costs
(S
Million)
Average
Annual O&M
Costs (S)Per
Thousand
Gallons
Treated
Estimated
Treatment
Rate
(gpm)
Remedial
Project
Manager and
Telephone
Number
Reference
Ion Exchange
Ace Services,
KS
Palmetto
Wood, SC
Sprague Road
Groundwater
Plume, TX
Cr
Cr
Cr
Ion exchange
Ion exchange
Ion exchange
0
3.7
0
-
-
-
$0.5
$0.3
$1.2
-
-
-
800
130
200
Bob Stewart
913-551-7364
Al Cherry
404-562-8807
Vincent
Mallot
214-665-8313
1.18
1.18
1.18
a The costs listed in this table include the costs for the entire groundwater treatment system at each site. Costs for United Chrome, Odessa I, and Odessa II are
in 1999 dollars. Information is not available on the cost year for other sites.
b The table lists only arsenic and chromium contaminants. Other contaminants may have been present and treated by the system.
0 The technology listed for each site is the technology that was intended to treat arsenic or chromium. Costs may include pre- or post-treatment
technologies associated with the arsenic or chromium treatment technologies.
d Years in operation for United Chrome, Odessa I, and Odessa II are as of early 1998. Years in operation for all other sites are as of May 2001.
e For the Odessa I site, reference 1.17 reports average annual O&M costs of $0.22 million (1999 dollars), while reference 1.18 reports $0.5 million (cost year
unknown).
Cr = Chromium As = Arsenic O&M = Operation and Maintenance - = Information is not available gpm = Gallons per minute
15
-------
Table 1.6
Summary of Cost3 Data for Treatment of Arsenic in Drinking Water
Technology
Precipitation/Coprecipitation
(coagulation-assisted
micro filtration)
Adsorption (greensand filtration)
Adsorption (activated alumina,
influent pH 7 - 8)
Ion exchange (anion exchange,
influent <20 mg/L sulfate)
Design Flow Rate
0.01 mgd
Capital Cost (S)
142,000
12,400
15,400
23,000
Annual O&M
Cost (S)
22,200
7,980
6,010
5,770
0.1 mgd
Capital Cost (S)
463,000
85,300
52,200
54,000
Annual O&M
Cost (S)
35,000
13,300
23,000
12,100
1 mgd
Capital Cost (S)
2,010,000
588,000
430,000
350,000
Annual O&M
Cost (S)
64,300
66,300
201,000
52,200
Source: Derived from Ref. 1.13
a Costs are rounded to three significant figures and are in September 1998 dollars. Costs do not include pretreatment or management of treatment residuals.
Costs for enhanced coagulation/filtration and enhanced lime softening are not presented because the costs curves for these technologies are for modification
of existing drinking water treatment systems only (Ref. 1.13), and are not comparable to those presented in Table 1.5, which are for new treatment systems.
mgd = million gallons per day
O&M = operating and maintenance
mg/L = milligrams per liter
< = less than
16
-------
2.0 PRECIPITATION/COPRECIPITATION FOR
ARSENIC
Summary
Precipitation/coprecipitation has been the most
frequently used method to treat arsenic-
contaminated water, including ground-water, surface
water, leachate, mine drainage, drinking water, and
wastewater in numerous pilot- and full-scale
applications. Based on the information collected for
this paper, this technology typically can reduce
arsenic concentrations to less than 0.050 mg/L and
in some cases has reduced arsenic concentrations to
below 0.010 mg/L.
Technology Description and Principles
For this issue paper, technologies were considered
precipitation/coprecipitation if they involved the
following steps:
Mixing of treatment chemicals into the water
Formation of a solid matrix through precipitation,
coprecipitation, or a combination of these
processes, and
Separation of the solid matrix from the water
Technologies that remove arsenic by passing it through
a fixed bed of media, where the arsenic may be removed
through adsorption, precipitation/coprecipitation, or a
combination of these processes, are discussed in the
adsorption treatment section (Section 3.0).
Precipitation/coprecipitation usually involves pH
adjustment and addition of a chemical precipitant or
coagulant, it can also include addition of a chemical
oxidant (Ref 2.1). Oxidation of arsenic to its less
soluble As(V) state can increase the effectiveness of
precipitation processes, and can be done as a separate
pretreatment step or as part of the precipitation process.
Some pretreatment processes that oxidize As(III) to
As(V) include ozonation, photo oxidation, or the
addition of oxidizing chemicals such as potassium
permanganate, sodium hypochlorite, or hydrogen
peroxide (Ref. 2.8, 2.16,2.22, 2.25,2.29). Clarification or
filtration are commonly used to remove the solid
precipitate.
Technology Description: Precipitation uses
chemicals to transform dissolved contaminants into
an insoluble solid. In coprecipitation, the target
contaminant may be dissolved or in a colloidal or
suspended form. Dissolved contaminants do not
precipitate, but are adsorbed onto another species
that is precipitated. Colloidal or suspended
contaminants become enmeshed with other
precipitated species, or are removed through
processes such as coagulation and flocculation.
Many processes to remove arsenic from aqueous
matrices involve a combination of precipitation and
coprecipitation. The precipitated/coprecipitated
solid is then removed from the liquid phase by
clarification or filtration. Arsenic precipitation/
coprecipitation can use combinations of the
chemicals and methods listed below.
Contaminants Treated:
Inorganics
Suspended solids
Colloids
Arsenic-Contaminated Media Treated:
Drinking water
Groundwater
Wastewater
Surface water
Leachate
Mine drainage
Chemicals and Methods Used for Arsenic
Precipitation/Coprecipitation:
Ferric salts (e.g.,
ferric chloride), ferric
sulfate, ferric
hydroxide
Ammonium sulfate
Alum (aluminum
hydroxide)
pH adjustment
Lime softening,
limestone, calcium
hydroxide
Manganese sulfate
Copper sulfate
Sulfide
Type, Number, and Scale of Identified Projects
Precipitation/coprecipitation processes for arsenic in
water are commercially available. The data gathered in
support of this issue paper include information on the
full-scale precipitation/coprecipitation treatment of
environmental media at 16 sites. Information on full-
scale treatment of drinking water is available for eight
facilities and on full-scale treatment of industrial
wastewater for at least 21 facilities. Figure 2.1 shows
17
-------
Model of a Precipitation/Coprecipitation System
Oxidation/
Reduction
(Pretreatment
Process)
Reagent
Polymer
Groundwater
Solids to
Disposal
pH Adjustment and
Reagent Addition
Effluent
Clarification
Sludge
Thickening
the number of pilot- and full-scale precipitation/
coprecipitation projects in the sources researched.
Figure 2.1
Scale of Identified Precipitation/Coprecipitation Projects
for Arsenic Treatment
Full
Pilot
24
45
10
20
30
40
50
Summary of Performance Data
Appendix A presents the available performance data for
pilot- and full-scale precipitation/coprecipitation
treatment of wastes and environmental media. It
contains information on 69 applications of
precipitation/coprecipitation, including 20
environmental media, 15 drinking water, and 34
industrial wastewater applications. The information
that appears in the "Precipitating Agent or Process"
column of Appendix A, including the chemicals used,
the descriptions of the precipitation/coprecipitation
processes, and whether the process involved
Precipitation/Coprecipitation Chemistry
The chemistry of precipitation/coprecipitation is
often complex, and depends upon a variety of
factors, including the speciation of arsenic, the
chemical precipitants used and their concentrations,
the pH of the water, and the presence of other
chemicals in the water be treated. As a result, the
particular mechanism that results in the removal of
arsenic through precipitation/coprecipitation
treatment is process-specific, and in some cases is
not completely understood. For example, the
removal mechanism in the treatment of As(V) with
Fe(III) has been debated in technical literature (Ref
2.34).
It is beyond the scope of this issue paper to provide
all possible chemical reactions and mechanisms for
precipitation/coprecipitation processes that are
used to remove arsenic. More detailed information
on the chemistry involved in specific precipitation/
coprecipitation processes can be found in the
references listed at the end of this section.
precipitation or coprecipitation, is based on the cited
references. This information was not independently
checked for accuracy or technical feasibility. For
example, in some cases, the reference used may apply
the term "precipitation" to a process that is actually
coprecipitation.
18
-------
Factors Affecting Precipitation/Coprecipitation
Performance
Valence state of arsenic - The presence of the
more soluble bivalent state of arsenic might
reduce the removal efficiency. The solubility of
arsenic depends upon its valence state, pH, the
specific arsenic compound, and the presence of
other chemicals with which arsenic might react
(Ref 2.12). Oxidation of bivalent arsenic to its
less soluble pentavalent state could improve
arsenic removal through
precipitation/coprecipitation (Ref. 2.7).
pH - In general, arsenic removal will be
maximized at the pH at which the precipitated
species is least soluble. The optimal pH range
for precipitation/coprecipitation depends upon
the waste treated and the specific treatment
process (Ref. 2.7).
Presence of other compounds - The presence of
other metals or contaminants can impact the
effectiveness of precipitation/coprecipitation.
For example, sulfate could decrease arsenic
removal in processes using ferric chloride as a
coagulant, while the presence of calcium or iron
may increase the removal of arsenic in these
processes (Ref. 2.7).
The effectiveness of precipitation/coprecipitation
treatment can be evaluated by comparing influent and
effluent contaminant concentrations. All of the 12
environmental media projects for which both influent
and effluent arsenic concentration data were available
had influent concentrations greater than 0.050 mg/L.
The treatments achieved effluent concentrations of less
than 0.050 mg/L in eight of the projects and less than
0.010 mg/L in four of the projects. Information on the
leachability of arsenic from the precipitates and sludges
was available for three projects. For all of these
projects, the leachable concentration of arsenic as
measured by the toxicity characteristic leaching
procedure (TCLP) (the RCRA regulatory threshold for
identifying a waste that is hazardous because it exhibits
the characteristic of toxicity for arsenic) was below 5
mg/L.
Of the 12 drinking water projects having both influent
and effluent concentration data, eight had influent
concentrations greater than 0.050 mg/L. The treatments
achieved effluent concentrations of less than 0.050
mg/L in all eight of these projects, and less than 0.010
mg/L in two projects. Information on the leachability of
arsenic from the precipitates and sludges was available
for six projects. For these projects the leachable
concentration of arsenic was below 5 mg/L.
All of the 28 wastewater projects having both influent
and effluent concentration data had influent
concentrations greater than 0.050 mg/L. The treatments
achieved effluent concentrations of less than 0.050
mg/L in 16 of these projects, and less than 0.010 mg/L in
11 projects. Information on the leachability of arsenic
from the precipitates and sludges was available for four
projects. Only one of these projects had a leachable
concentration of arsenic below 5 mg/L.
Projects that did not reduce arsenic concentrations to
below 0.050 or 0.010 mg/L do not necessarily indicate
that precipitation/coprecipitation cannot achieve these
levels. The treatment goal for some applications could
have been above these concentrations, and the
technology may have been designed and operated to
meet a higher concentration. Information on treatment
goals was not collected for this issue paper.
Some projects in Appendix A include treatment trains,
the most common being precipitation followed by
activated carbon adsorption or membrane filtration. In
those cases, the projects are listed in all the relevant
appendices. For example, Project 17 in Appendix A
describes a treatment using a train consisting of air
stripping, metals precipitation, filtration, and ion
exchange. This project also appears as Project 2 in
Appendix C, which contains performance data for ion
exchange treatment.
The case study presented at the end of this section
discusses in greater detail the removal of arsenic from
groundwater using an aboveground treatment system
at the Winthrop Landfill Superfund site. Information for
this site is summarized in Appendix A, Project 1.
Advantages and Potential Limitations
Precipitation/coprecipitation is an active ex situ
treatment technology designed to function with routine
chemical addition and sludge removal. It usually
generates a sludge residual, which typically requires
treatment such as dewatering and subsequent disposal.
Some sludge from the precipitation/coprecipitation of
19
-------
arsenic can be a hazardous waste and require additional
treatment such as solidification/stabilization prior to
disposal. In the presence of other metals or
contaminants, arsenic precipitation/coprecipitation
processes might also cause other compounds to
precipitate, which can render the resulting sludge
hazardous (Ref. 2.7). The effluent may also require
further treatment, such as pH adjustment, prior to
discharge or reuse.
More detailed information on selection and design of
arsenic treatment systems for small drinking water
systems is available in the document "Arsenic
Treatment Technology Design Manual for Small
Systems" (Ref. 2.38).
Summary of Cost Data
Limited cost data are currently available for
precipitation/coprecipitation treatment of arsenic. At
the Winthrop Landfill Site (Appendix A, Project 1),
groundwater containing arsenic, 1,1-dichloroethane,
and vinyl chloride is being pumped and treated above
ground through a treatment train that includes
precipitation. The total capital cost of this treatment
system was $2 million ($1.8 million for construction and
$0.2 million for design). O&M costs were about $
350,000 per year fro the first few years and are now
approximately $250,000 per year. The treatment system
has a capacity of 65 gallons per minute (gpm).
However, these costs are for the entire treatment train
(Ref. 2.29, cost year not provided). At the power
substation in Fort Walton, Florida, (Appendix A,
Project 4), the reported O&M cost was $0.006 per gallon
(for the entire treatment train, Ref. 2.33, cost year not
provided). Capital cost information was not provided.
Table 1.5 lists the cost of two aboveground treatment
systems for arsenic and five systems for chromium
using precipitation/coprecipitation. Additional
information for the treatment systems is presented in
Appendix A, Projects 1 and 19.
A low-cost, point-of-use precipitation/coprecipitation
treatment designed for use in developing nations with
arsenic-contaminated drinking water was pilot-tested in
four areas of Bangladesh (Appendix A, Project 32).
This simple treatment process consists of a two-bucket
system that uses potassium permanganate and alum to
precipitate arsenic, followed by sedimentation and
filtration. The equipment cost of the project was
approximately $6, and treatment of 40 liters of water
daily would require a monthly chemical cost of $0.20.
The document "Technologies and Costs for Removal of
Arsenic From Drinking Water" (Ref. 2.7) contains more
information on the cost of systems to treat arsenic in
drinking water to below the revised MCL of 0.010 mg/L.
The document includes capital and O&M cost curves
for three precipitation/coprecipitation processes:
Enhanced coagulation/filtration
Enhanced lime softening
Coagulation-assisted microfiltration
Factors Affecting Precipitation/Coprecipitation
Costs
Type of chemical addition - The chemical added
will affect costs. For example, calcium
hypochlorite is a less expensive oxidant than
potassium permanganate (Ref. 2.16).
Chemical dosage - The cost generally increases
with increased chemical addition. Larger
amounts of chemicals added usually results in a
larger amount of sludge requiring additional
treatment or disposal (Ref. 2.7, 2.12).
Treatment goal -Application could require
additional treatment to meet stringent cleanup
goals and/or effluent and disposal standards
(Ref. 2.7).
Sludge disposal - Sludge produced from the
precipitation/coprecipitation process could be
considered a hazardous waste and require
additional treatment before disposal, or require
disposal as hazardous waste (Ref. 2.7).
Factors affecting precipitation/coprecipitation
performance - Items in the "Factors Affecting
Precipitation/Coprecipitation Performance" box
will also affect costs.
These cost curves are based on computer cost models
for drinking water treatment systems. Table 1.6
contains cost estimates based on these curves for
coagulation assisted microfiltration. The cost
information available for enhanced coagulation/
filtration and enhanced lime softening are for retrofitting
existing precipitation/coprecipitation systems at
drinking water treatment plants to meet the revised
MCL. Therefore, the cost information could not be
used to estimate the cost of a new precipitation/
coprecipitation treatment system.
20
-------
Retrofitting Existing Systems
The revised MCL for arsenic in drinking water could
result in lower treatment goals for aboveground
treatment systems. A lower goal can significantly affect
the selection, design, and operation of treatment
systems. In some cases, existing systems may need to
be retrofitted to achieve lower treatment goals.
Modifications to precipitation/coprecipitation treatment
systems that can help reduce the effluent
concentrations of arsenic include:
Use of additional treatment chemicals
Use of different treatment chemicals
Addition of another technology to the treatment
train, such as membrane filtration
However, these modifications might result in additional
costs for purchasing additional or more expensive
treatment chemicals and disposing of increased
amounts of treatment residuals. For example, use of
more treatment chemicals is likely to increase the
amount of sludge generated.
Case Study: Winthrop Landfill Site
The Winthrop Landfill site, located in Winthrop,
Maine, is a former dump site that accepted municipal
and industrial wastes (Appendix A, Project 1).
Groundwater at the site was contaminated with
arsenic and chlorinated and nonchlorinated VOCs.
A pump-and-treat system for the groundwater has
been in operation at the site since 1995. Organic
compounds have been remediated to below action
levels, and the pump-and-treat system is currently
being operated for the removal of arsenic alone.
The treatment train consists of equalization/pH
adjustment to pH 3, chemical oxidation with
hydrogen peroxide, precipitation/coprecipitation via
pH adjustment to pH 7, flocculation/clarification,
and sand bed filtration. The system currently treats
65 gpm of groundwater containing average
concentrations of arsenic at 0.3 mg/L to a
concentration below 0.005 mg/L. Through May
2001, 359 pounds of arsenic had been removed from
groundwater at the Winthrop Landfill site using this
aboveground treatment system. Capital costs for
the system were about $2 million, and current O&M
costs are approximately $250,000 per year (Ref. 2.29).
Reference 2.7 contains cost curves for capital and O&M
costs associated with retrofitting coagulation/filtration
and lime softening drinking water treatment systems to
meet the revised MCL of 0.010 mg/L.
References
2.1 Federal Remediation Technologies Reference
Guide and Screening Manual, Version 3.0. Federal
Remediation Technologies Roundtable
http://www.frtr.gov./matrix2/top _page.html.
2.2 Twidwell, L.G.,etal. Technologies and Potential
Technologies for Removing Arsenic from Process
and Mine Wastewater. Presented at "REWAS
'99." San Sebastian, Spain. September 1999.
http: //www.mtech. edu/metallurgy/arsenic/
REWASAS%20for%20proceedings99%20in%20w
ord.pdf
2.3 U. S. EPA. Final Best Demonstrated Available
Technology (BDAT) Background Document for
K031, K084, K101, K102, Characteristic Arsenic
Wastes (D004), Characteristic Selenium Wastes
(D010), and P and U Wastes Containing Arsenic
and Selenium Listing Constituents. Office of Solid
Waste. May 1990.
2.4 U.S. EPA. Best Demonstrated Available
Technology (BDAT) Background Document for
Wood Preserving Wastes: F032, F034, and F035;
Final. April, 1996. http://www.epa.gov/
epaoswer/hazwaste/ldr/wood/bdat_bd.pdf
2.5 U.S. EPA. Pump and Treat of Contaminated
Groundwater at the Baird and McGuire Superfund
Site, Holbrook, Massachusetts. Federal
Remediation Technologies Roundtable.
September, 1998.
http://www.frtr.gov/costperf.html.
2.6 U.S. EPA. Development Document for Effluent
Limitations Guidelines and Standards for the
Centralized Waste Treatment Industry. December,
2000. http://www.epa.gov/ost/guide/cwt/final/
devtdoc.html
2.7 U.S. EPA. Technologies and Costs for Removal
of Arsenic From Drinking Water. EPA-R-00-028.
Office of Water. December, 2000.
http://www.epa.gov/safewater/ars/
treatments_and_co sts. pdf
21
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2.8 U.S. EPA. Treatment Technologies for Site
Cleanup: Annual Status Report (Tenth Edition).
Office of Solid Waste and Emergency Response.
EPA-542-R-01-004. February 2001.
http://www.epa.gov/ncepi/Catalog/
EPA542R01004.html
2.9 U U. S. EPA National Risk Management Research
Laboratory. Treatability Database.
2.10 U.S. EPA Technology Innovation Office.
Database for EPA REACH IT (REmediation And
CHaracterization Innovative Technologies).
http://www.epareachit.org. March, 2001.
2.11 Electric Power Research Institute. Innovative
Technologies for Remediation of Arsenic in Soil
Groundwater: Soil Flushing, In-Situ Fixation, Iron
Coprecipitation, and Ceramic Membrane Filtration.
http://www.epri.com. 1996.
2.12 U.S. EPA Office of Research and Development.
Contaminants and Remedial Options at Selected
Metal-Contaminated Sites. EPA/540/R-95/512.
July, 1995. http://search.epa.gov/s97is.vts
2.13 U. S. EPA Office of Solid Waste and Emergency
Response. 1997 Biennial Reporting System
Database.
2.14 E-mail attachment from Doug Sutton, Geotrans,
Inc., to Linda Fiedler, U.S. EPA. April 20,2001.
2.15 U.S. EPA. Office of Solid Waste and Emergency
Response. 1997. Biennial Reporting System.
Draft Analysis.
2.16 MSE Technology Applications, Inc. Arsenic
Oxidation Demonstration Project - Final Report.
January 1998. http://www.arsenic.org/
PDF%20Files/Mwtp-84.pdf
2. 17 Vendor information provided by MSE Technology
Applications, Inc.
2.18 HYDRO-Solutions and Purification. June 28, 2001.
http://www.mosquitonet.com/~hydro
2.19 DPHE-Danida Arsenic Mitigation Pilot Project.
June 28, 2001. http://phys4.harvard.edu/~wilson/
2bucket.html.
2.20 Environmental Research Institute. Arsenic
Remediation Technology - AsRT. June 28,2001.
http://www.eng2.uconn.edu/~nikos/
asrt-brochure.html
2.21 A Simple Household Device to Remove Arsenic
from Groundwater Hence Making it Suitable for
Drinking and Cooking. June 28, 2001
http: //phy s4 .harvard. edu/~wilson/
asfilterl. html
2.22 Appropriate Remediation Techniques for Arsenic-
Contaminated Wells in Bangladesh. June 28,2001.
http: //phy s4. harvard, edu/ -wilson/murcott. html
2.23 Redox Treatment of Groundwater to Remove Trace
Arsenic at Point-of-Entry Water Treatment
Systems. June 28, 2001
http://phys4.harvard.edu/~wilson/Redox/
Desc.html
2.24 U.S. EPA Office of Water. Arsenic in Drinking
Water. August 3, 2001. http://www.dainichi-
consul.co.jp/english/arsenic/treatl.htm.
2.25 U.S. EPA Office of Research and Development.
Arsenic Removal from Drinking Water by
Coagulation/Filtration and Lime Softening Plants.
EPA/600/R-00/063. June, 2000.
http://www.epa.gov/ncepi/Catalog/
EPA600R00063.html
2.26 U.S. EPA and NSF International. ETV Joint
Verification Statement for Chemical
Coagulant/Filtration System Used in Packaged
Drinking Water Treatment Systems. March, 2001.
2.27 FAMU-FSU College of Engineering. Arsenic
Remediation. August 21,2001.
http: //www. eng. fsu.edu/departments/civil/
research/arsenicremedia/index.htm
2.28 U.S. EPA. Contaminants and Remedial Options at
Selected Metal-Contaminated Sites. Office of
Research and Development. EPA-540-R-95-512.
July 1995.
2.29 E-mail attachment sent from Anni Loughlin of U.S.
EPA Region I to Linda Fiedler, U.S. EPA. August
21,2001.
2.30 U.S. EPA. Arsenic & Mercury - Workshop on
Removal, Recovery, Treatment, and Disposal.
Office of Research and Development. EPA-600-R-
92-105. August 1992.
2.31 U.S. EPA. Profiles of Metal Recovery
Technologies for Mineral Processing and Other
Metal-Bearing Hazardous Wastes. December
1994.
2.32 U.S. EPA. Groundwater Pump and Treat Systems:
Summary of Selected Cost and Performance
Information at Superfund-financed Sites. EPA-
542-R-01-021b. EPA OSWER. December 2001.
http://clu-in.org
2.33 Miller JP, Hartsfield TH, Corey AC, Markey RM.
In Situ Environmental Remediation of an
Energized Substation. EPRI. Palo Alto, CA.
Report No. 1005169.2001.
22
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2.34 Robins, Robert G. Some Chemical Aspects
Relating To Arsenic Remedial Technologies.
Proceedings of the U.S. EPA Workshop on
Managing Arsenic Risks to the Environment.
Denver, Colorado. May 1-3, 2001.
2.35 U. S. EPA Office of Solid Waste and Emergency
Response. Arsenic Treatment Technologies for
Soil, Waste, and Water. EPA 542-R-02-004.
September 2002.
2.36 E-mail from Bhupi Khona, U.S. EPA Region 3 to
SankalpaNagaraja, Tetra Tech EM, Inc., regarding
Ground-water Pump-and-Treat of Arsenic at the
Whitmoyer Laboratories Superfund site. May 3,
2002.
2.37 Hydroglobe LLC. Removal of Arsenic from
Bangladesh Well Water by the Stevens
Technology for Arsenic Removal (S.T.A.R.).
Hoboken, NJ. http://www.hydroglobe.net.
2.38 U.S. EPA. Arsenic Treatment Technology Design
Manual for Small Systems (100% Draft for Peer
Review). June 2002. http://www.epa.gov/
safewater/smallsys/
arsenicdesignmanualpeerreviewdraft.pdf
23
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3.0 ADSORPTION TREATMENT FOR ARSENIC
Summary
Adsorption has been used to treat ground-water and
drinking water containing arsenic. Based on the
information collected for this paper, this technology
typically can reduce arsenic concentrations to less
than 0.050 mg/L and in some cases has reduced
arsenic concentrations to below 0.010 mg/L. Its
effectiveness is sensitive to a variety of untreated
water contaminants and characteristics. It is used
less frequently than precipitation/coprecipitation,
and is most commonly used to treat groundwater
and drinking water, or as a polishing step for other
water treatment processes.
Technology Description and Principles
Technology Description: In adsorption, solutes
(contaminants) concentrate at the surface of a
sorbent, thereby reducing their concentration in the
bulk liquid phase. The adsorption media is usually
packed into a column. As contaminated water is
passed through the column, contaminants are
adsorbed. When adsorption sites become filled, the
column must be regenerated, or disposed of and
replaced with new media.
Contaminants Treated:
Dissolved organics
Dissolved metals
Arsenic-Contaminated Media Treated:
Groundwater
Drinking water
Types of Sorbent Used to Treat Arsenic:
Activated alumina (AA)
Activated carbon (AC)
Copper-zinc granules
Granular ferric hydroxide, ferric hydroxide-
coated newspaper pulp, iron oxide-coated sand,
iron filings mixed with sand
Greensand filtration (KMnO4 coated glauconite)
Proprietary media
Surfactant-modified zeolite
This section discusses arsenic removal processes that
use a fixed bed of media through which water is passed.
Some of the processes described in this section rely on
a combination of adsorption, precipitation/
coprecipitation, ion exchange, and filtration. However,
the primary removal mechanism in each process is
adsorption in a fixed bed of media. For example,
greensand is made from glauconite, a green, iron-rich,
clay-like mineral that usually occurs as small pellets
mixed with other sand particles. The glauconite-
containing sand is treated with potassium
permanganate (KMnO4), forming a layer of manganese
oxides on the sand. As water passes through a
greensand filtration bed, the KMnO4 oxidizes As(III) to
As(V), and As(V) adsorbs onto the greensand surface.
Model of an Adsorption System
Contaminated
Water '
In addition, arsenic is removed by ion exchange,
displacing species from the manganese oxide
(presumably hydroxide ion [OH"] and water [H2O]).
When the KMnO4 is exhausted, the greensand media
must be regenerated or replaced. Greensand media is
regenerated with a solution of excess KMnO4.
Greensand filtration is also known as oxidation/filtration
(Ref. 3.3).
Activated alumina (AA) is the sorbent most commonly
used to remove arsenic from drinking water (Ref. 3.1)
and has also been used for groundwater (Ref. 3.4). The
reported adsorption capacity of AA ranges from 0.003
to 0.112 grams of arsenic per gram of AA (Ref. 3.4). AA
is available in different mesh sizes, and its particle size
affects contaminant removal efficiency. Up to 23,400
bed volumes of wastewater can be treated before AA
24
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requires regeneration or disposal and replacement with
new media (Ref. 3.3). AA regeneration is a four-step
process:
Backwashing
Regeneration
Neutralization
Rinsing
The regeneration process desorbs the arsenic. The
regeneration fluid most commonly used for AA
treatment systems is a solution of sodium hydroxide.
The most commonly used neutralization fluid is a
solution of sulfuric acid. The regeneration and
neutralization steps for AA adsorption systems might
produce a sludge because the alumina can be dissolved
by the strong acids and bases used in these processes,
forming an aluminum hydroxide precipitate in the spent
regeneration and neutralization fluids. This sludge
typically contains a high concentration of arsenic (Ref.
3.1).
Activated carbon (AC) is an organic sorbent that is
commonly used to remove organic and metal
contaminants from drinking water, groundwater, and
wastewater (Ref. 3.4). AC media are normally
regenerated using thermal techniques to desorb and
volatilize contaminants (Ref. 3.6). However,
regeneration of AC media used for the removal of
arsenic from water might not be feasible (Ref. 3.4). The
arsenic might not volatilize at the temperatures typically
used in AC regeneration. In addition, off-gas
containing arsenic from the regeneration process might
be difficult or expensive to manage.
The reported adsorption capacity of AC is 0.020 grams
of As(V) per gram of AC (Ref. 3.4). As(III) is not
effectively removed by AC (Ref. 3.4). AC impregnated
with metals such as copper and ferrous iron has a
higher reported adsorption capacity for arsenic. The
reported adsorption capacity for As(III) is 0.048 grams
per gram of copper-impregnated carbon and for As(V),
the capacity is 0.2 grams per gram of ferrous iron-
impregnated carbon (Ref. 3.4).
Iron-based adsorption media include granular ferric
hydroxide, ferric hydroxide-coated newspaper pulp, iron
oxide-coated sand, and iron filings mixed with sand.
These media have been used primarily to remove
arsenic from drinking water. Processes that use these
media typically remove arsenic using adsorption in
combination with oxidation, precipitation/
coprecipitation, ion exchange, or filtration. For example,
iron oxide-coated sand uses adsorption and ion
exchange with surface hydroxides to selectively remove
arsenic from aqueous streams. The media requires
periodic regeneration or disposal and replacement with
new media. The regeneration process is similar to that
used for AA and consists of rinsing the media with a
regenerating solution containing excess sodium
hydroxide, flushing with water, and neutralizing with a
strong acid, such as sulfuric acid (Ref. 3.3).
The sources used for this issue paper contained
information on the use of surfactant-modified zeolite
(SMZ) at bench scale, but no pilot- or full-scale
applications were identified. SMZ is prepared by
treating zeolite with a solution of surfactant, such as
hexadecyltrimethylammonium bromide (HDTMA-Br).
This process forms a stable coating on the zeolite
surface. The reported adsorption capacity of SMZ is
0.0055 grams of As(V) per gram of SMZ at 25°C. SMZ
must be periodically regenerated with surfactant
solution or disposed and replaced with new SMZ (Ref.
3.17).
Adsorption can be operated using multiple beds in
series to reduce the need for media regeneration; beds
first in the series will require regeneration first, and
fresh beds can be added at the end of the series.
Multiple beds can also allow for continuous operation
because some of the beds can be regenerated while
others continue to treat water.
Type, Number, and Scale of Identified Projects
Adsorption technologies to treat arsenic-contaminated
water in environmental media and drinking water are
commercially available. Information is available on 23
applications of adsorption (Figure 3.1), including 12
environmental media and 11 drinking water applications.
The data sources used for this report describe seven
full-scale applications of adsorption to environmental
media and eight full-scale applications to drinking
water.
Summary of Performance Data
Adsorption treatment effectiveness can be evaluated by
comparing influent and effluent contaminant
concentrations. Appendix B presents the available
performance data for this technology. Two of the four
25
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Figure 3.1
Scale of Identified Adsorption Projects for Arsenic
Treatment
Full
Pilot
15
10
environmental media projects having both influent and
effluent arsenic concentration data had influent
concentrations greater than 0.050 mg/L. Effluent
concentrations of 0.050 mg/L or less were achieved in
both of the projects. In the other two projects, the
influent concentration was between 0.010 mg/L and
0.050 mg/L, and the effluent concentration was less
than 0.010 mg/L.
Factors Affecting Adsorption Performance
Wastewater pH - The optimal pH to maximize
adsorption of arsenic by activated alumina is
acidic (pH 6). Therefore, pretreatment and post-
treatment of the water could be required (Ref
3.4).
Arsenic oxidation state - Adsorption is more
effective in removing As(V) than As(III) (Ref.
3.12).
Flow rate - Increasing the rate of flow through
the adsorption unit can decrease the adsorption
of contaminants (Ref. 3.1).
Fouling - The presence of suspended solids,
organics, silica, or mica can cause fouling of
adsorption media (Ref. 3.1, 3.4).
Of the ten drinking water projects (eight full- and two
pilot-scale) having both influent and effluent arsenic
concentration data, eight had influent concentrations
greater than 0.050 mg/L. Effluent concentrations of
less than 0.050 mg/L were achieved in seven of these
15
projects. For two drinking water projects the influent
concentration was between 0.010 mg/L and 0.050 mg/L,
and the effluent concentration was less than 0.010
mg/L.
Projects that did not reduce arsenic concentrations to
below 0.050 or 0.010 mg/L do not necessarily indicate
that adsorption cannot achieve these levels. The
treatment goals for some applications could have been
above these levels, and the technology may have been
designed and operated to meet a higher arsenic
concentration. Information on treatment goals was not
collected for this issue paper.
Two pilot-scale studies were performed to compare the
effectiveness of AA adsorption on As(III) and As(V)
(Appendix B, Projects 3 and 4). For As(III), 300 bed
volumes were treated before arsenic concentrations in
the effluent exceeded 0.050 mg/L, whereas 23,400 bed
volumes were treated for As(V) before reaching the
same concentration in the effluent. The results of these
studies indicate that the adsorption capacity of AA is
much greater for As(V).
The case study in this section discusses in greater
detail the use of AA to remove arsenic from drinking
water. Information for this project is summarized in
Appendix B, Project 12.
Advantages and Potential Limitations
For AA adsorption media, the spent regenerating
solution might contain a high concentration of arsenic
and other sorbed contaminants, and can be corrosive
(Ref. 3.3). Spent AA is produced when the AA can no
longer be regenerated (Ref. 3.3). The spent AA may
require treatment prior to disposal (Ref. 3.4). Because
regeneration of AA requires the use of strong acids and
bases, some of the AA media becomes dissolved
during the regeneration process. This can reduce the
adsorptive capacity of the AA and cause the AA
packing to become "cemented."
Regeneration of AC media normally involves the use of
thermal energy, which could release volatile arsenic
compounds. Use of air pollution control equipment
may be necessary to remove arsenic from the off-gas
produced (Ref. 3.6).
Competition for adsorption sites could reduce the
effectiveness of adsorption because other constituents
26
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might be preferentially adsorbed, resulting in a need for
more frequent bed regeneration or replacement. The
presence of sulfate, chloride, and organic compounds
has reportedly reduced the adsorption capacity of AA
for arsenic (Ref 3.3). The order for adsorption
preference for AA is provided below, with constituent
having the greatest adsorption preference appearing at
the top left (Ref. 3.3):
OH' > H2As04- > Si(OH)30- > F' > HSeCV > SO42' >
H3AsO3
This technology's effectiveness is also sensitive to a
variety of contaminants and characteristics in the
untreated water, and suspended solids, organics, silica,
or mica can cause fouling. Therefore, it is typically
applied to groundwater and drinking water, which are
less likely to contain fouling contaminants. It may also
be used as a polishing step for other water treatment
technologies.
More detailed information on selection and design of
arsenic treatment systems for small drinking water
systems is available in the document "Arsenic
Treatment Technology Design Manual for Small
Systems" (Ref. 3.21).
Summary of Cost Data
One source reported that the cost of removing arsenic
from drinking water using AA ranged from $0.003 to
$0.76 per 1,000 gallons (Ref. 3.4, cost year not
provided). The document "Technologies and Costs for
Removal of Arsenic From Drinking Water" (Ref. 3.3)
contains more detailed information on the cost of
adsorption systems to treat arsenic in drinking water to
below the revised MCL of 0.010 mg/L. The document
includes capital and O&M cost curves for four
adsorption processes:
AA (at various influent pH levels)
Granular ferric hydroxide
Greensand filtration (KMNO4 - coated sand)
AA point-of-use systems
These cost curves are based on computer cost models
for drinking water treatment systems. The curves show
the costs for adsorption treatment systems with
different design flow rates. The document also
contains information on the disposal cost of residuals
from adsorption. Although this issue paper focuses on
the aboveground treatment of arsenic-contaminated
groundwater, many of the same treatment technologies
used to treat drinking water are also applicable to
aboveground treatment of groundwater and may have
similar costs.
Factors Affecting Adsorption Costs
Contaminant concentration - Very high
concentrations of competing contaminants may
require frequent replacement or regeneration of
adsorbent (Ref. 3.2). The capacity of the
adsorption media increases with increasing
contaminant concentration (Ref. 3.1, 3.4). High
arsenic concentrations can exhaust the
adsorption media quickly, resulting in the need
for frequent regeneration or replacement.
Spent media - Spent media that can no longer
be regenerated might require treatment or
disposal (Ref. 3.4).
Factors affecting adsorption performance -
Items in the "Factors Affecting Adsorption
Performance" box will also affect costs.
Retrofitting Existing Systems
Modifications to adsorption treatment systems that
could reduce the effluent concentrations of arsenic to
meet the revised MCL of 0.010 mg/L include:
Addition of an adsorption media bed
Use of a different adsorption media
More frequent replacement or regeneration of
adsorption media
Decrease in the flow rate of water treated
Addition of another treatment technology to the
treatment train, such as membrane filtration
However, these modifications could result in additional
costs for purchasing additional or more expensive
adsorption media, more frequent regeneration of
adsorption media, and increased amounts of
treatment.residuals. For example, more frequent
regeneration of adsorption media is likely to generate
greater volumes of spent regeneration fluid, and result
in higher disposal costs.
27
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Case Study: Treatment of Drinking Water By An
Activated Alumina Plant
A drinking water treatment plant using AA
(Appendix B, Project 1) installed in February 1996,
has an average flow rate of 3,000 gpd. The arsenic
treatment system consists of two parallel treatment
trains, with two AA columns in series in each train.
For each of the trains, the AA media in one column
is exhausted and replaced every 1 to 1.5 years after
treating approximately 5,260 bed volumes.
Water samples for a long-term evaluation were
collected weekly for a year. Pretreatment arsenic
concentrations at the inlet ranged from 0.053 to
0.087 mg/L, with an average of 0.063 mg/L. The
untreated water contained primarily As(V), with only
minor concentrations of As(III) and particulate
arsenic. During the entire evaluation, the arsenic
concentration in the treated drinking water was
below 0.003 mg/L. Spent AA from the system had
leachable arsenic concentrations of less than
0.05 mg/L, as measured by the TCLP, and therefore,
could be disposed of as nonhazardous waste.
References
3.1 U.S. EPA. Regulations on the Disposal of Arsenic
Residuals from Drinking Water Treatment Plants.
Office of Research and Development. EPA/600/R-
00/025. May 2000.
http://www.epa.gov/ORD/WebPubs/residuals/
index.htm
3.2 Federal Remediation Technologies Reference
Guide and Screening Manual, Version 3.0. Federal
Remediation Technologies Roundtable. March
30, 2001. http://www.frtr.gov/matrix2/
top_page.html.
3.3 U.S. EPA. Technologies and Costs for Removal
of Arsenic From Drinking Water. EPA 815-R-OO-
028. Office of Water. December 2000.
http://www.epa.gov/safewater/ars/
treatments_and_costs.pdf
3.4 Twidwell, L.G., et al. Technologies and Potential
Technologies for Removing Arsenic from Process
and Mine Wastewater. Presented at
"REWAS'99." San Sebastian, Spain. September
1999. http://www.mtech. edu/metallurgy/arsenic/
REWASAS%20for%20proceedings99%20in%20w
ord.pdf
3.5 U.S. EPA. Pump and Treat of Contaminated
Groundwater at the Mid-South Wood Products
Superfund Site, Mena, Arkansas. Federal
Remediation Technologies Roundtable.
September 1998.
http://www.frtr.gov/costperf.html.
3.6 U.S. EPA. Final Best Demonstrated Available
Technology (BOAT) Background Document for
K031, K084, K101, K102, Characteristic Arsenic
Wastes (D004), Characteristic Selenium Wastes
(D010), and P and U Wastes Containing Arsenic
and Selenium Listing Constituents. Office of Solid
Waste. May 1990.
3.7 E-mail attachment sent from Doug Sutton of
Geotrans, Inc., to Linda Fiedler, U.S. EPA. April
20,2001.
3.8 Murcott S. Appropriate Remediation
Technologies for Arsenic-Contaminated Wells in
Bangladesh. Massachusetts Institute of
Technology. February 1999.
http://web.mit.edu/civenv/html/people/faculty/
murcott.html
3.9 Haq N. Low-cost method developed to treat
arsenic water. West Bengal and Bangladesh
Arsenic Crisis Information Center. June 2001.
http://bicn.com/acic/resources/infobank/nfb/
2001-06-ll-nv4n593.htm
3.10 U.S. EPA. Arsenic Removal from Drinking Water
by Iron Removal Plants. EPA 600-R-00-086. Office
of Research and Development. August 2000.
http: //www. epa. go v/ORD/WebPubs/iron/
index.html
3.11 Harbauer GmbH & Co. KG. Germany. Online
address: http://www.harbauer-berlin.de/arsenic.
3.12 U.S. EPA. Arsenic Removal from Drinking Water
by Ion Exchange and Activated Alumina Plants.
EPA 600-R-00-088. Office of Research and
Development. October 2000.
http://www.epa.gov/ncepi/Catalog/
EPA600R00088.
3.13 Environmental Research Institute. Arsenic
Remediation Technology - AsRT. June 28, 2001.
http: //www. eng2. uconn.edu/~nikos/asrt-
brochure.html.
3.14 Redox Treatment of Groundwater to Remove Trace
Arsenic at Point-of-Entry Water Treatment
Systems. June 28, 2001.
http://phys4.harvard.edu/~wilson/Redox/
Desc.html.
28
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3.15 U.S. EPA. Treatment Technologies for Site
Cleanup: Annual Status Report (Tenth Edition).
Office of Solid Waste and Emergency Response.
EPA-542-R-01-004. February 2001.
http://clu-in.org/asr
3.16 Electric Power Research Institute. Innovative
Technologies for Remediation of Arsenic in Soil
Groundwater: Soil Flushing, In-Situ Fixation, Iron
Coprecipitation, and Ceramic Membrane Filtration.
April 2000. http://www.epri.com
3.17 Sullivan, E. I, Bowman, R S., and Leieic, LA.
Sorption of Arsenate from Soil-Washing Leachate
by Surfactant-Modified Zeolite. Prepublication
draft. January, 2002. bowman@nmt.edu
3.18 U. S. EPA Office of Solid Waste and Emergency
Response. Arsenic Treatment Technologies for
Soil, Waste, and Water. EPA 542-R-02-004.
September 2002.
3.19 E-mail attachment from Cindy Schreier, Prima
Environmental to Sankalpa Nagaraja, Tetra Tech
EM Inc. June 18, 2002.
3.20 Severn Trent Services. UK.
http://www.capitalcontrols.co.uk/
3.21 U.S. EPA. Arsenic Treatment Technology Design
Manual for Small Systems (100% Draft for Peer
Review). June 2002.
http://www.epa.gov/ safewater/smallsys/
arsenicdesignmanualpeerreviewdraft.pdf
29
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4.0 ION EXCHANGE FOR ARSENIC
Summary
Ion exchange has been used to treat groundwater
and drinking water containing arsenic. Based on the
information collected to prepare this paper, this
technology typically can reduce arsenic
concentrations to less than 0.050 mg/L and in some
cases has reduced arsenic concentrations to below
0.010 mg/L. Its effectiveness is sensitive to a variety
of untreated water contaminants and characteristics.
It is used less frequently than precipitation/
coprecipitation, and is most commonly used to treat
groundwater and drinking water, or as a polishing
step for other water treatment processes.
Technology Description and Principles
Technology Description: Ion exchange is a
physical/chemical process in which ions held
electrostatically on the surface of a solid are
exchanged for ions of similar charge in a solution. It
removes ions from the aqueous phase by the
exchange of cations or anions between the
contaminants and the exchange medium (Ref 4.1,
4.4,4.8).
Contaminants Treated:
Dissolved inorganic ions
Arsenic-Contaminated Media Treated:
Groundwater
Surface water
Drinking water
Ion Exchange Media Used to Treat Arsenic:
Strong base anion exchange resins
The medium used for ion exchange is typically a resin
made from synthetic organic materials, inorganic
materials, or natural polymeric materials that contain
ionic functional groups to which exchangeable ions are
attached (Ref. 4.3). Four types of ion exchange media
have been used (Ref. 4.1):
Strong acid
Weak acid
Strong base
Weak base
Strong and weak acid resins exchange cations while
strong and weak base resins exchange anions. Because
dissolved arsenic is usually in an anionic form, and
weak base resins tend to be effective over a smaller pH
range, strong base resins are typically used for arsenic
treatment (Ref. 4.1).
Model of an Ion Exchange System
Contaminated
Resins may also be categorized by the ion that is
exchanged with the one in solution. For example, resins
that exchange a chloride ion are referred to as chloride-
form resins. Another way of categorizing resins is by
the type of ion in solution that the resin preferentially
exchanges. For example, resins that preferentially
exchange sulfate ions are referred to as sulfate-
selective. Both sulfate-selective and nitrate-selective
resins have been used for arsenic removal (Ref. 4.1).
The resin is usually packed into a column, and as
contaminated water is passed through the column,
contaminant ions are exchanged for other ions such as
chloride or hydroxide in the resin (Ref. 4.4). Ion
exchange is often preceded by treatments such as
filtration and oil-water separation to remove organics,
suspended solids, and other contaminants that can foul
the resins and reduce their effectiveness.
Ion exchange resins must be periodically regenerated to
remove the adsorbed contaminants and replenish the
30
-------
exchanged ions (Ref. 4.4). Regeneration of a resin
occurs in three steps:
Backwashing
Regeneration with a solution of ions
Final rinsing to remove the regenerating solution
The regeneration process results in a backwash
solution, a waste regenerating solution, and a waste
rinse water. The volume of spent regeneration solution
ranges from 1.5 to 10 percent of the treated water
volume depending on the feed water quality and type of
ion exchange unit (Ref. 4.4). The number of ion
exchange bed volumes that can be treated before
regeneration is needed can range from 300 to 60,000
(Ref. 4.1). The regenerating solution can be used up to
25 times before treatment or disposal is required. The
final rinsing step usually requires only a few bed
volumes of water (Ref. 4.4).
Ion exchange can be operated using multiple beds in
series to reduce the need for bed regeneration; beds
first in the series will require regeneration first, and
fresh beds can be added at the end of the series.
Multiple beds can also allow for continuous operation
because some of the beds can be regenerated while
others continue to treat water. Ion exchange beds are
typically operated as a fixed bed, in which the water to
be treated is passed over an immobile ion exchange
resin. One variation on this approach is to operate the
bed in a non-fixed, countercurrent fashion in which
water is applied in one direction, usually downward,
while spent ion exchange resin is removed from the top
of the bed. Regenerated resin is added to the bottom of
the bed. This method can reduce the frequency of resin
regeneration (Ref. 4.4).
Type, Number, and Scale of Identified Projects
Ion exchange technology for arsenic in environmental
media and drinking water is commercially available.
Information is available on seven full-scale applications
(Figure 4.1), including three applications to
environmental media and four applications to drinking
water. No pilot-scale applications or applications to
industrial wastewater were found in the sources
researched.
Figure 4.1
Scale of Identified Ion Exchange Projects for Arsenic
Treatment
Full
Pilot
Summary of Performance Data
Appendix C presents the available performance data for
this technology. Ion exchange treatment effectiveness
can be evaluated by comparing influent and effluent
contaminant concentrations. The single environmental
media project with both influent and effluent arsenic
concentration data had an influent concentration of
Factors Affecting Ion Exchange Performance
Valence state - As(III) is generally not removed
by ion exchange (Ref. 4.4).
Presence of competing ions - Competition for
the exchange ion can reduce the effectiveness
of ion exchange if ions in the resin are replaced
by ions other than arsenic, resulting in a need
for more frequent bed regeneration (Ref. 4.1,
4.9).
Fouling - The presence of organics, suspended
solids, calcium, or iron, can cause fouling of ion
exchange resins (Ref. 4.4).
Presence of trivalent iron - The presence of
Fe(III) could cause arsenic to form complexes
with the iron that are not removed by ion
exchange (Ref. 4.1).
pH - For chloride-form, strong-base resins, a pH
in the range of 6.5 to 9 is optimal. Outside of
this range, arsenic removal effectiveness
decreases quickly (Ref. 4.1).
31
-------
0.0394 mg/L, and an effluent concentration of 0.0229
mg/L.
Of the three drinking water projects with both influent
and effluent concentration data, all had influent
concentrations greater than 0.010 mg/L. Effluent
concentrations of less than 0.010 mg/L were
consistently achieved for only one of these projects.
Projects that did not reduce arsenic concentrations to
below 0.050 or 0.010 mg/L do not necessarily indicate
that ion exchange cannot achieve these levels. The
treatment goal for some applications could have been
above these levels and the technology may have been
designed and operated to meet a higher arsenic
concentration. Information on treatment goals was not
collected for this issue paper.
The case study at the end of this section further
discusses the use of ion exchange to remove arsenic
from drinking water. Information for this project is
summarized in Appendix C, Project 6.
Advantages and Potential Limitations
For ion exchange systems using chloride-form resins,
the treated water could contain increased levels of
chloride ions and as a result be corrosive. Chlorides
can also increase the redox potential of iron, thus
increasing the potential for water discoloration if the
iron is oxidized. The ion exchange process can also
lower the pH of treated waters (Ref 4.4).
For ion exchange resins used to remove arsenic from
water, the spent regenerating solution might contain a
high concentration of arsenic and other sorbed
contaminants, and could be corrosive. Spent resin is
produced when the resin can no longer be regenerated.
The spent resin may require treatment prior to reuse or
disposal.
The order for exchange for most strong-base resins is
provided below, with the constituent with the greatest
adsorption preference appearing at the top left (Ref.
4.4).
HCrO4- > CrO42- > C1O4" > SeO42' > SO42' > NO3" > Br
(HPO42-, HAsO42-, SeO32-, CO32') > CN" > NO2" > Cl"
>(H2PO4-, H2AsO4-, HCO3-) > OH" > CH3COO' > F"
The effectiveness of ion exchange is also sensitive to a
variety of contaminants and characteristics in the
untreated water, and organics, suspended solids,
calcium, or iron can cause fouling. Therefore, it is
typically applied to groundwater and drinking water,
which are less likely to contain fouling contaminants. It
may also be used as a polishing step for other water
treatment technologies.
More detailed information on selection and design of
arsenic treatment systems for small drinking water
systems is available in the document "Arsenic
Treatment Technology Design Manual for Small
Systems" (Ref. 4.10).
Summary of Cost Data
One project reported a capital cost for an ion exchange
system of $6,886 with an additional $2,000 installation
fee (Ref. 4.9, cost year not provided). The capacity of
the system and O&M costs were not reported. Cost
data for other projects using ion exchange were not
available.
The document "Technologies and Costs for Removal of
Arsenic From Drinking Water" (Ref. 4.1) contains
additional information on the cost of ion exchange
systems for treating arsenic in drinking water to levels
below the revised MCL of 0.010 mg/L. The document
includes capital and O&M cost curves for ion exchange
at various influent sulfate (SO4)concentrations. These
cost curves are based on computer cost models for
drinking water treatment systems.
Factors Affecting Ion Exchange Costs
Bed regeneration - Regenerating ion exchange
beds reduces the amount of waste for disposal
and the cost of operation (Ref. 4.8).
Sulfate - Sulfate (SO4) can compete with arsenic
for ion exchange sites, thus reducing the
exchange capacity of the ion exchange media
for arsenic. This can result in a need for more
frequent media regeneration or replacement,
and associated higher costs (Ref. 4.1).
Factors affecting ion exchange performance -
Items in the "Factors Affecting Ion Exchange
Performance" box will also affect costs.
32
-------
The curves estimate the costs for ion exchange
treatment systems with different design flow rates. The
document also contains information on the disposal
cost for residuals from ion exchange. Although this
issue paper focuses on the aboveground treatment of
arsenic-contaminated groundwater, many of the
technologies used to treat drinking water are applicable
to aboveground treatment of groundwater and may
have similar costs.
Retrofitting Existing Systems
Modifications to ion exchange treatment systems that
can help reduce the effluent concentrations of arsenic
to meet the revised MCL of 0.010 mg/L include:
Addition of an ion exchange bed
Use of a different ion exchange resin
More frequent regeneration or replacement of ion
exchange media
Decrease in the flow rate of water treated
Addition of another technology to the treatment
train, such as membrane filtration
However, these modifications could increase costs for
purchasing additional or more expensive resin, more
frequent regeneration of resin, and increased amounts
of treatment residuals. For example, more frequent
regeneration of resin is likely to generate greater
volumes of spent regeneration fluid.
Case Study: National Risk Management Research
Laboratory Study
A study by EPA ORD's National Risk Management
Research Laboratory tested an ion exchange system
at a drinking water treatment plant. Weekly
sampling for 1 year showed that the plant achieved
an average of 97 percent arsenic removal. The resin
columns were frequently regenerated (every 6 days).
Influent arsenic concentrations ranged from 0.045 to
0.065 mg/L and effluent concentrations ranged from
0.0008 to 0.0045 mg/L (Ref 4.9) (Appendix C, Project
6).
References
4.1 U.S. EPA. Technologies and Costs for Removal
of Arsenic From Drinking Water. EPA-R-00-028.
Office of Water. December, 2000.
http://www.epa.gov/safewater/ars/
treatments_and_co sts. pdf
4.2 U.S. EPA. Arsenic & Mercury - Workshop on
Removal, Recovery, Treatment, and Disposal.
Office of Research and Development. EPA-600-R-
92-105. August 1992.
http://www.epa.gov/ncepihom
4.3 Federal Remediation Technologies Reference
Guide and Screening Manual, Version 3.0.
Federal Remediation Technologies Roundtable
(FRTR).
http://www.frtr.gov/matrix2/top_page.html.
4.4 U.S. EPA. Regulations on the Disposal of
Arsenic Residuals from Drinking Water
Treatment Plants. EPA-600-R-00-025. Office of
Research and Development. May 2000.
http://www.epa.gov/ncepihom
4.5 Tidwell, L.G., et al. Technologies and Potential
Technologies for Removing Arsenic from
Process and Mine Wastewater. Presented at
"REWAS'99." San Sebastian, Spain. September
1999. http://www.mtech.edu/metallurgy/arsenic/
REWASAS%20for%20proceedings99%20in%20
word.pdf
4.6 U.S. EPA. Final Best Demonstrated Available
Technology (BOAT) Background Document for
K031, K084, K101, K102, Characteristic Arsenic
Wastes (D004), Characteristic Selenium Wastes
(DO 10), and P and U Wastes Containing Arsenic
and Selenium Listing Constituents. Office of
Solid Waste. May 1990.
4.7 E-mail attachment sent from Doug Sutton of
Geotrans, Inc., to Linda Fiedler, U.S. EPA. April
20,2001.
4.8 Murcott, S. Appropriate Remediation
Technologies for Arsenic-Contaminated Wells in
Bangladesh. Massachusetts Institute of
Technology. February 1999.
http: //web .mil edu/ci venv/html/people/facuity /
murcott.html
4.9 U.S. EPA. Arsenic Removal from Drinking Water
by Ion Exchange and Activated Alumina Plants.
EPA-600-R-00-088. Office of Research and
Development. October 2000.
http: //www. epa. go v/ORD/WebPubs/exchange/E
PA600R00088.pdf
33
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4.10 U.S. EPA. Arsenic Treatment Technology
Design Manual for Small Systems (100% Draft for
Peer Review). June 2002.
http://www.epa.gov/safewater/smallsys/
arsenicdesignmanualpeerreviewdraft.pdf
34
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5.0 MEMBRANE FILTRATION FOR ARSENIC
Summary
Membrane filtration can remove a wide range of
contaminants from water. Based on the information
collected to prepare this paper, this technology
typically can reduce arsenic concentrations to less
than 0.050 mg/L and in some cases has reduced
arsenic concentrations to below 0.010 mg/L.
However, its effectiveness is sensitive to a variety
of untreated water contaminants and characteristics.
It also produces a larger volume of residuals and
tends to be more expensive than other arsenic
treatment technologies. Therefore, it is used less
frequently than precipitation/coprecipitation,
adsorption, and ion exchange. It is most commonly
used to treat groundwater and drinking water, or as
a polishing step for precipitation processes. Only
two full-scale projects using membrane filtration to
treat arsenic were identified in the sources
researched for this paper.
Technology Description and Principles
Technology Description: Membrane filtration
separates contaminants from water by passing it
through a semipermeable barrier or membrane. The
membrane allows some constituents to pass
through, while blocking others (Ref 5.2, 5.3).
Contaminants Treated:
Dissolved
inorganics
Suspended solids
Dissolved organics
Colloids
Arsenic-Contaminated Media Treated:
Drinking water Surface water
Groundwater Industrial
wastewater
Types of Membrane Processes:
Microfiltration
(MF)
Ultrafiltration (UF)
Nanofiltration (NF)
Reverse osmosis
(RO)
There are four types of membrane processes: reverse
osmosis (RO), nanofiltration (NF), microfiltration (MF),
and ultrafiltration (UF). All four are pressure-driven and
are categorized by the size of the particles that can pass
through the membranes or by the molecular weight limit
(i.e., pore size) of the membrane (Ref. 5.2). The force
required to drive fluids across the membranes depends
on the pore size; NF and RO require a relatively high
pressure (50 to 150 pounds per square inch [psi]), while
MF and UF require a relatively low pressure (5 to 100
psi). The low-pressure processes primarily remove
contaminants through physical sieving and the high-
pressure processes primarily remove contaminants
through chemical diffusion across the permeable
membrane (Ref. 5.4).
Because arsenic species dissolved in water tend to
have relatively low molecular weights, only NF and RO
membrane processes are likely to effectively treat
dissolved arsenic (Ref. 5.4). MF has been used in
conjunction with precipitation/coprecipitation to
remove solids containing arsenic. The sources used for
this issue paper did not contain any information on the
use of UF to remove arsenic; therefore, UF is not
discussed in this technology summary. Membrane
filtration processes generate two treatment residuals
from the influent waste stream: a treated effluent
(permeate) and a rejected waste stream of concentrated
contaminants (reject).
Model of a Membrane Filtration System
Contaminated
Water
35
-------
RO is a high-pressure process that primarily removes
smaller ions typically associated with total dissolved
solids. The molecular weight cutoff for RO membranes
ranges from 1 to 20,000, which is a significantly lower
limit than for NF membranes (Ref 5.4). The molecular
weight cutoff for NF membranes ranges from
approximately 150 to 20,000. NF is a high-pressure
process that primarily removes larger divalent ions
associated with hardness (for example, calcium [Ca],
and magnesium [Mg]) but not monovalent salts (for
example, sodium [Na] and chlorine [Cl]). NF is slightly
less efficient than RO in removing dissolved arsenic
from water (Ref. 5.4).
MF is a low-pressure process that primarily removes
particles with a molecular weight above 50,000 or a
particle size greater than 0.050 micrometers. The pore
size of MF membranes is too large to effectively remove
dissolved arsenic species, but MF can remove
particulates containing arsenic and solids produced by
precipitation/coprecipitation processes (Ref. 5.4).
Type, Number, and Scale of Identified Projects
The data gathered for this paper identified one full-scale
RO and one full-scale MF treatment of arsenic in
groundwater and surface water (Figure 5.1). The MF
application is a treatment train consisting of
precipitaiton/coprecipitation followed by MF to remove
solids. In addition, 16 pilot-scale and three bench-scale
applications of RO and eight pilot-scale and three
bench-scale applications of NF have been identified.
One pilot-scale application of MF to remove solids from
precipitation/coprecipitation processes has also been
identified.
Figure 5.1
Scale of Identified Membrane Filtration Projects for
Arsenic Treatment
Full
Pilot
Bench
25
Summary of Performance Data
Appendix D presents the available performance data for
this technology. Performance results for membrane
filtration are typically reported as percent removal, (i.e.,
the percentage of arsenic, by mass, in the influent that
is removed or rejected from the influent wastewater
stream). A higher percentage indicates greater removal
of arsenic, and therefore, more efficient treatment.
Although many of the projects listed in Appendix D
may have reduced arsenic concentrations to levels
below 0.050 mg/L or 0.010 mg/L, data on the arsenic
concentrations in the effluent and reject streams were
not available for most projects.
Factors Affecting Membrane Filtration
Performance
Suspended solids, high molecular weight,
dissolved solids, organic compounds, and
colloids - The presence of these constituents in
the feed stream could cause membrane fouling
(Ref. 5.2).
Oxidation state of arsenic - Prior oxidation of
the influent stream to convert As(III) to As(V)
will increase arsenic removal; As(III) is smaller
and diffuses more easily through the membrane
than As(V) (Ref. 5.2).
pH - pH might affect the adsorption of arsenic
on the membrane by creating an electrostatic
charge on the membrane surface (Ref. 5.4).
Temperature - Low influent stream
temperatures decrease membrane flux.
Increasing system pressure or increasing the
membrane surface area can compensate for low
influent stream temperature (Ref. 5.4).
10
15
20
25
For two RO projects, the arsenic concentration in the
reject stream was available, allowing the concentration
in the permeate to be calculated. For both projects, the
concentration of arsenic prior to treatment was greater
than 0.050 mg/L, and was reduced to less than 0.010
mg/L in the treated water.
For two projects involving removal of solids from
precipitation/coprecipitation treatment of arsenic with
MF, the arsenic concentration in the permeate was
available. The concentration prior to precipitation/
coprecipitation treatment was greater than 0.050 mg/L
36
-------
for one project, and ranged from 0.005 to 3.8 mg/L for
the other. For both projects, the concentrations in the
treated water were less than 0.005 mg/L.
The case study at the end of this section further
discusses the use of membrane filtration to remove
arsenic from groundwater used as a drinking water
source. Information for this site is summarized in
Appendix D, Project 31.
Advantages and Potential Limitations
Membrane technologies are capable of removing a wide
range of dissolved contaminants and suspended solids
from water (Ref. 5.12). RO andNF technologies require
no chemical addition to ensure adequate separation.
This type of treatment can be run in either batch or
continuous mode. This technology's effectiveness is
sensitive to a variety of contaminants and
characteristics in the untreated water. Suspended
solids, organics, colloids, and other contaminants can
cause membrane fouling. Therefore, it is typically
applied to groundwater and drinking water, which are
less likely to contain fouling contaminants. It is also
applied to remove solids from precipitation processes
and as a polishing step for other water treatment
technologies when lower concentrations must be
achieved.
More detailed information on selection and design of
arsenic treatment systems for small drinking water
systems is available in the document "Arsenic
Treatment Technology Design Manual for Small
Systems" (Ref. 5.16).
Summary of Cost Data
The research conducted for support of this issue paper
did not document any cost data for specific membrane
filtration projects to treat arsenic. However, the
document "Technologies and Costs for Removal of
Arsenic From Drinking Water" (Ref. 5.4) contains
additional information on the cost of point-of-use
reverse osmosis systems to treat arsenic in drinking
water to levels below the revised MCL of 0.010 mg/L.
The document includes capital and O&M cost curves
for this technology. These cost curves are based on
computer cost models for drinking water treatment
systems.
Factors Affecting Membrane Filtration Costs
Type of membrane filtration - The type of
membrane selected could affect the cost of the
treatment (Ref. 5.1,5.2).
Initial waste stream - Certain waste streams
may require pretreatment, which would increase
costs (Ref. 5.4).
Rejected waste stream - Based on
concentrations of the removed contaminant,
further treatment might be required prior to
disposal or discharge (Ref. 5.4).
Factors affecting membrane filtration
performance - Items in the "Factors Affecting
Membrane Filtration Performance" box will also
affect costs.
Retrofitting Existing Systems
Modifications to membrane filtration treatment systems
that could help reduce the effluent concentrations of
arsenic to meet the revised MCL of 0.010 mg/L include:
1. Increasing the volume of reject generated per
volume of water treated
2. Using a membrane with a smaller molecular weight
cutoff
3. Decreasing the flow rate of water treated
4. Adding another treatment technology to the
treatment train, such as ion exchange
However, these modifications can result in additional
costs for more expensive membranes and increased
amounts of treatment residuals requiring disposal. For
example, increasing the volume of reject generated per
volume of water treated will produce greater volumes of
reject that require treatment or disposal.
37
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Case Study: Park City Spiro Tunnel Water Filtration
Plant
The Park City Spiro Tunnel Water Filtration Plant in
Park City, Utah treats ground-water from water-
bearing fissures that collect in a tunnel of an
abandoned silver mine to generate drinking water.
A pilot-scale RO unit treated contaminated water at
a flow rate of 0.77 gpm from the Spiro tunnel for 34
days. The total and dissolved arsenic in the
feedwater averaged 0.065 and 0.042 mg/L,
respectively. The total and dissolved arsenic
concentrations in the permeate averaged <0.0005
and less than <0.0008 mg/L, respectively. The RO
process reduced average As(V) from 0.035 to 0.0005
mg/L and average As(III) from 0.007 to 0.0005 mg/L.
The membrane achieved 99% total As removal and
98% As(V) removal (Ref 5.12) (Appendix D, Project
31).
References
5.1 U.S. EPA Office of Research and Development.
Arsenic & Mercury - Workshop on Removal,
Recovery, Treatment, and Disposal. EPA-600-R-
92-105. August 1992.
5.2 U.S. EPA Office of Research and Development.
Regulations on the Disposal of Arsenic Residuals
from Drinking Water Treatment Plants. Office of
Research and Development. EPA-600-R-00-025.
May 2000.
http: //www. epa. go v/ORD/WebPubs/
residuals/index.htm
5.3 U.S. EPA Office of Solid Waste. BOAT
Background Document for Spent Potliners from
Primary Aluminum Reduction - K088. EPA 530-R-
96-015. February 1996.
http://www.epa.gov/ncepi/Catalog/
EPA530R96015.html
5.4 U.S. EPA Office of Water. Technologies and Cost
for Removal of Arsenic from Drinking Water. EPA
815-R-00-028. December 2000.
http://www.epa.gov/safewater/ars/
treatments_and_costs.pdf
5.5 U.S. EPA National Risk Management Research
Laboratory. Treatability Database. March 2001.
5.6 U.S. Technology Innovation Office. Database for
EPA REACH IT (REmediation And
CHaracterization Innovative Technologies).
http://www.epareachit.org. March 2001.
5.7 Environmental Technology Verification Program
(ETV). Reverse Osmosis Membrane Filtration
Used In Packaged Drinking Water Treatment
Systems, http://www.membranes.com. March
2001.
5.13 Electric Power Research Institute. Innovative
Technologies for Remediation of Arsenic in Soil
Groundwater: Soil Flushing, In-Situ Fixation,
Iron Coprecipitation, and Ceramic Membrane
Filtration, http://www.epri.com. April 2000.
5.14 FAMU-FSU College of Engineering. Arsenic
Remediation.
http: //www. eng. fsu.edu/departments/civil/
research/arsenicremedia/index.htm August 21,
2001.
5.15 U.S. EPA Office of Solid Waste and Emergency
Response. Arsenic Treatment Technologies for
Soil, Waste, and Water. EPA-542-R-02-004.
September 2002.
5.16 U.S. EPA. Arsenic Treatment Technology Design
Manual for Small Systems (100% Draft for Peer
Review). June 2002. http://www.epa.gov/
safewater/smallsy s/
arsenicdesignmanualpeerreviewdraft.pdf
38
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Appendix A
Precipitation/Coprecipitation Treatment
Performance Data for Arsenic
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic
Project
Number
Industry or Site
Type
Waste or
Media
Scale3
Site Name
Initial Arsenic
Concentration
Final Arsenic
Concentration
Precipitate
Arsenic
Concentration
Precipitating Agent
or Process0
d
Environmental Media - Coagulation/Filtration
1
2
Landfill
Metal ore mining
and smelting
Groundwater
Surface water,
8,500,000
gallons
Full
Full
Winthrop
Landfill
Superfund Site,
Winthrop, ME
Tex-Tin
Superfund Site,
OU1,TX
0.300 mg/L
-
<0.005 mg/L
-
-
-
Treatment train
consisting of pH
adjustment,
oxidation,
flocculation/
clarification, air
stripping, and sand-
bed filtration
Precipitation by pH
adjustment followed
by filtration
2.29
2.8
Environmental Media - Iron Coprecipitation
3
4
Herbicide
application
Energized
substation
Groundwater
Groundwater,
44 million
gallons
Full
Full
-
Fort. Walton
Beach, FL
0.005 -3. 8 mg/L
0.2-1.0 mg/L
O.005 -
0.05 mg/L
<0.005 mg/L
<5 mg/L (TCLP)
-
Iron coprecipitation
followed by
membrane filtration
Iron coprecipitation
followed by ceramic
membrane filtration
2.27
2.33
A-l
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
5
6
7
8
9
Industry or Site
Type
Chemical mixing
Wood preserving
wastes
Metal ore mining
and smelting
activities
Herbicide
application
Metals
processing
Waste or
Media
Ground-water
Ground-water
Collection
pond water
Groundwater
Leachate from
nickel roaster
flue dust
disposal area
Scale3
Full
Full
Pilot
Pilot
Pilot
Site Name
Baird and
McGuire
Superfund Site,
Holbrook, MA
Silver Bow
Creek/Butte Area
Superfund Site -
Rocker Timber
Framing And
Treatment Plant
OU, MT
Ryan Lode Mine,
AK
-
Susie
Mine/Valley
Forge site,
Rimini, MT
Initial Arsenic
Concentration
-
-
4.6 mg/L
Img/L
423 - 439 mg/L
Final Arsenic
Concentration
-
-
0.027 mg/L
<0.005 mg/L
<0.32 mg/L
Precipitate
Arsenic
Concentration
-
-
-
-
102,000 mg/kg
(TWA)
0.547-0.658
mg/L (TCLP)
Precipitating Agent
or Process0
Treatment train
consisting of air
stripping,
precipitation (ferric
chloride, lime slurry,
phosphoric and
sulfuric acids, and
ammonium sulfate),
filtration, and
carbon adsorption
In situ treatment of
contaminated
groundwater by
injecting a solution
of ferrous iron,
limestone, and
potassium
permanganate
Enhanced iron
coprecipitation
followed by
filtration
Iron coprecipitation
followed by ceramic
membrane filtration
Photo-oxidation of
arsenic followed by
iron coprecipitation
Source
d
2.5,
2.14
2.8
2.18
2.11
2.16
A-2
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
10
Industry or Site
Type
Metal ore mining
Waste or
Media
Acid mine
water
Scale3
Pilot
Site Name
Susie
Mine/Valley
Forge site,
Rimini, MT
Initial Arsenic
Concentration
12.2 - 16.5 mg/L
Final Arsenic
Concentration
0.017-
0.053 mg/L
Precipitate
Arsenic
Concentration
8,830-13,300
mg/kg (TWA)
0.0051-0.0076
mg/L (TCLP)
Precipitating Agent
or Process0
Photo-oxidation of
arsenic followed by
iron coprecipitation
Source
2.16
Environmental Media - Other or Unspecified Precipitation Process
11
12
13
14
15
16
-
-
Chemical
manufacturing
wastes,
ground-water
Chemical
manufacturing
Groundwater
"Superfund
wastewater"6
"Superfund
wastewater"6
Groundwater
Groundwater
Groundwater,
65,000 gpd
Full
Full
Full
Full
Full
Full
-
-
Peterson/Puritan
Inc. Superfund
Site-OUl,PAC
Area, RI
Greenwood
Chemical
Superfund Site,
Greenwood, VA
100 mg/L
0.1 - 1 mg/L
0.1 - 1 mg/L
100 mg/L
< 0.2 mg/L
0.022 mg/L
0.1 10 mg/L
O.010 mg/L
-
-
-
Chemical
precipitation
Chemical
precipitation
Reductive
precipitation
(additional
information not
available)
In situ treatment of
arsenic-
contaminated
groundwater by
injecting
oxygenated water
Treatment train
consisting of metals
precipitation,
filtration, UV
oxidation and
carbon adsorption
2.17
2.9
2.9
2.17
2.8
2.14
A-3
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
17
18
19
20
Industry or Site
Type
Waste disposal
Wood preserving
Herbicide
manufacturing
Veterinary feed
additives and
Pharmaceuticals
manufacturing
Waste or
Media
Groundwater,
43,000 gpd
Groundwater,
3,000 gpd
Groundwater,
RCRA waste
codeKOSl,
1 mgd
Groundwater,
50-100 gpm
Scale3
Full
Full
Full
Full
Site Name
EUggins Farm
Superfund Site,
Franklin
Township, NJ
Saunders Supply
Company
Superfund Site,
Chuckatuck, VA
Vineland
Chemical
Company
Superfund Site,
Vineland, NJ
Whitmoyer
Laboratories
Superfund Site,
PA
Initial Arsenic
Concentration
100 mg/L
Final Arsenic
Concentration
0.025 mg/L
Precipitate
Arsenic
Concentration
Precipitating Agent
or Process0
Treatment train
consisting of air
stripping, metals
precipitation,
filtration, and ion
exchange
Treatment train
consisting of metals
precipitation,
filtration, and
carbon adsorption.
Metals precipitation
followed by
filtration
Neutralization and
flocculation by
increasing pH to 9
Source
2.14
2.14
2.14
2.36
A-4
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
Industry or Site
Type
Waste or
Media
Scale3
Site Name
Initial Arsenic
Concentration
Final Arsenic
Concentration
Precipitate
Arsenic
Concentration
Precipitating Agent
or Process0
Source
d
Drinking Water - Iron Coprecipitation
21
22
23
24
25
26
-
-
-
-
-
-
Drinking
water, 1.6
mgd
Drinking
water, 1 .4
mgd
Drinking
water
Drinking
water
Drinking
water, 600
mgd
Drinking
water,
62.5 mgd
Full
Full
Full
Full
Full
Full
-
-
McGrath Road
Baptist Church,
AK
-
-
-
0.0203 mg/L
0.0485 mg/L
0.370 mg/L
Plant A:
0.02 mg/L
Plant B:
0.049 mg/L
0.0026 -
0.0121 mg/L
0.015-
0.0239 mg/L
0.0030 mg/L
0.01 13 mg/L
<0.005 mg/L
Plant A:
0.003 mg/L
Plant B:
0.012 mg/L
0.0008 -
0.006 mg/L
0.0015-
0.01 18 mg/L
<5 mg/L (WET)
<5 mg/L (WET)
-
-
806-880 mg/kg
(TWA)
O.05 -
0.106 mg/L
(TCLP)
293-493 mg/kg
(TWA)
0.058 -
0.1 14 mg/L
(TCLP)
Ferric
coprecipitation
followed by zeolite
softening
Ferric
coprecipitation
Enhanced iron
coprecipitation
followed by
filtration
Adsorption and
coprecipitation with
iron hydroxide
precipitates
Ozonation followed
by coagulation with
iron- and aluminum-
based additives and
filtration
Coagulation with
iron- and aluminum-
based additives,
sedimentation, and
filtration
2.7
2.7
2.18
2.10
2.25
2.25
A-5
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
27
28
29
Industry or Site
Type
-
-
-
Waste or
Media
Drinking
water, 1.0-
1.1 gpm
Drinking
water
Drinking
water, 5.3
gallons
Scale3
Pilot
Pilot
Pilot
Site Name
Spiro Tunnel
Water Filtration
Plant, Park City,
UT
-
Bhariab &
Sreenagar Thana,
Bangladesh
Initial Arsenic
Concentration
0.0609 -
0.146 mg/L
-
0.28 - 0.59 mg/L
Final Arsenic
Concentration
0.0012-
0.0345 mg/L
<0.002 mg/L
Arsenic (V)
O.03 - 0.05 mg/L
Precipitate
Arsenic
Concentration
-
-
1194mg/kg
Precipitating Agent
or Process0
Precipitation with
ferric chloride and
sodium
hypochlorite,
followed by
filtration
Iron coagulation
with direct filtration
Iron co-precipitation
followed by
filtration
Source
d
2.26
2.24
2.37
Drinking Water - Lime Softening
30
31
-
-
Drinking
water, 10
mgd
Drinking
water
Full
Full
-
Five facilities,
identification
unknown
0.0159-
0.0849 mg/L
-
0.0063 -
0.0331 mg/L
<0.003 mg/L
17.0-35.3
mg/kg (TWA)
<0.05 mg/L
(TCLP)
<5 mg/L (TCLP)
Oxidation followed
by lime softening
and filtration
Lime softening at
pH>10.2
2.25
2.7
Drinking Water - Point-of-Use Systems
32
-
Drinking
water, 40
liters per day
Pilot
Noakhali,
Bangladesh
0.12 -0.46 mg/L
O.05 mg/L
-
Coagulation with
potassium
permanganate and
alum, followed by
sedimentation and
filtration
2.19
A-6
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
33
34
35
Industry or Site
Type
-
-
-
Waste or
Media
Drinking
water
Drinking
water
Drinking
water, 20
liters per day
Scale3
Pilot
Pilot
Pilot
Site Name
Harian Village
Rajshaji District
Bangladesh
West Bengal,
India
West Bengal,
India
Initial Arsenic
Concentration
0.092 -
0.120mg/L
0.300 mg/L
-
Final Arsenic
Concentration
0.023 -
0.036 mg/L
0.030 mg/L
-
Precipitate
Arsenic
Concentration
-
-
-
Precipitating Agent
or Process0
Naturally-occuring
iron at 9 mg/L
facilitates
precipitation,
followed by
sedimentation,
filtration and
acidification
Precipitation with
sodium hypochlorite
and alum, followed
by mixing,
flocculation,
sedimentation, and
up-flow filtration
Precipitation by
ferric salt, oxidizing
agent, and activated
charcoal, followed
by sedimentation
and filtration
Source
d
2.22
2.22
2.21
Wastewaters - Lime Softening
36
37
-
-
K084,
wastewater
Wastewater
Full
Full
Charles City,
Iowa
-
399 -1,670 mg/L
4.2 mg/L
Calcium arsenate,
60.5 - 500 mg/L
0.51 mg/L
45,200 mg/kg
(TWA) 2,200
mg/L (TCLP)
-
Calcium hydroxide
Lime precipitation
followed by
sedimentation
2.3
2.4
A-7
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
38
39
Industry or Site
Type
-
-
Waste or
Media
Wastewater
Wastewater
Scale3
Full
Full
Site Name
-
BP Minerals
America
Initial Arsenic
Concentration
4.2 mg/L
-
Final Arsenic
Concentration
0.34 mg/L
-
Precipitate
Arsenic
Concentration
-
Calcium
arsenate and
calcium
arsenite, 1,900 -
6,900 mg/kg
(TWA) 0.2 -
74.5 mg/L
(EPT)
Precipitating Agent
or Process0
Lime precipitation
followed by
sedimentation and
filtration
Lime
Source
d
2.4
2.3
Wastewaters - Metal Sulfates
40
41
-
Metals
processing
K084,
wastewater
Spent
leachate from
the recover}'
ofCu,Ag,
and Sb from
ores (amount
not available)
Full
Full
Charles City,
Iowa
Equity Silver
Mine, Houston,
British
Columbia,
Canada
125 - 302 mg/L
-
Manganese
arsenate, 6.02 -
22.4 mg/L
-
47,400 mg/kg
(TWA)
984 mg/L
(TCLP)
95 to 98%
recovery of
arsenic
Manganese sulfate
Acid addition,
chemical
precipitation with
copper sulfate, and
filtration
2.3
2.30
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
42
Industry or Site
Type
Metals
processing
Waste or
Media
Leachate from
filter cake
from
purification of
zinc sulfate
electro-
winning
solution
(amount not
available)
Scale3
Full
Site Name
Texasgulf
Canada,
Timmons,
Ontario, Canada
Initial Arsenic
Concentration
-
Final Arsenic
Concentration
-
Precipitate
Arsenic
Concentration
98% recovery of
arsenic
Precipitating Agent
or Process0
Acid addition,
chemical
precipitation with
copper sulfate, and
filtration
Source
d
2.30
Wastewaters - Iron Coprecipitation
43
44
-
-
K084,
wastewater
Wastewater
from wet
scrubbing of
incinerator
vent gas
(D004,P011)
Full
Full
Charles City,
Iowa
American NuKem
15-107mg/L
69.6-83.7mg/L
Ferric arsenate,
0.163-
0.580 mg/L
<0.02 - 0.6 mg/L
9,760 mg/kg
(TWA)
0.508 mg/L
(TCLP)
-
Ferric sulfate
Chemical oxidation
followed by
precipitation with
ferric salts
2.3
2.3
Wastewaters - Other or Unspecified Precipitation Process
45
-
Wastewater
Full
-
<0.1-3.0mg/L
0.1 8 mg/L
-
Chemical reduction
followed by
precipitation,
sedimentation, and
filtration
2.4
A-9
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
46
47
48
Industry or Site
Type
Centralized waste
treatment
industry
Centralized waste
treatment
industry
Centralized waste
treatment
industry
Waste or
Media
Wastewater
Wastewater
Wastewater
Scale3
Full
Full
Full
Site Name
-
-
-
Initial Arsenic
Concentration
57mg/L
57mg/L
57mg/L
Final Arsenic
Concentration
0.181 mg/L
0.246 mg/L
0.084 mg/L
Precipitate
Arsenic
Concentration
-
-
-
Precipitating Agent
or Process0
Primary
precipitation with
solids- liquid
separation
Primary
precipitation with
solids- liquid
separation followed
by secondary
precipitation with
solids- liquid
separation
Primary
precipitation with
solids- liquid
separation followed
by secondary
precipitation with
solids- liquid
separation and
multimedia filtration
Source
2.6
2.6
2.6
A-10
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
49
50
51
52
53
54
Industry or Site
Type
Centralized waste
treatment
industry
Chemical and
allied products
-
Transportation
equipment
industry
Chemicals and
allied products
Metals
processing
Waste or
Media
Wastewater
Wastewater
Domestic
wastewater
Wastewater
Wastewater
Spent
leachate from
the recovery
of silver (Ag)
from ores
(amount not
available)
Scale3
Full
Full
Full
Full
Full
Full
Site Name
-
-
-
-
-
Sheritt Gordon
Mines, LTD.,
Fort
Saskatchewan,
Alberta, Canada
Initial Arsenic
Concentration
57mg/L
Ob-0.1mg/L
Ob-0.1mg/L
0.1 - 1 mg/L
0.1 - 1 mg/L
-
Final Arsenic
Concentration
0.0 11 mg/L
0.0063 mg/L
0.00 15 mg/L
<0.002 mg/L
0.028 mg/L
-
Precipitate
Arsenic
Concentration
-
-
-
-
-
-
Precipitating Agent
or Process0
Selective metals
precipitation, solids-
liquid separation,
secondary
precipitation,
solids- liquid
separation, tertiary
precipitation, and
solid-liquid
separation
Chemically assisted
clarification
Chemical
precipitation
Chemical
precipitation and
filtration
Chemically assisted
clarification
Chemical
precipitation and
filtration
Source
d
2.6
2.9
2.9
2.9
2.9
2.30
A-ll
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
55
56
57
58
59
60
Industry or Site
Type
Metallurgie-
Hoboken-
Overpelt (MHO)
solvent
extraction
process,
metals
processing
WR Metals
Industries
(WRMI) arsenic
leaching process,
metals
processing
Electric, gas, and
sanitary
Primary metals
-
Waste or
Media
Spent
electrolyte
from copper
(Cu) refining
(amount not
available)
Leachate from
arsenical flue-
dusts from
non-ferrous
smelters
(amount not
available)
Wastewater
Wastewater
Wastewater
bearing
unspecified
RCRA listed
waste code
Domestic
wastewater
Scale3
Full
Full
Pilot
Pilot
Pilot
Pilot
Site Name
Olen, Belgium
WR Metals
Industries
(location not
available)
-
-
-
Initial Arsenic
Concentration
110,000-
550,000 mg/kg
Ob-0.1mg/L
Ob-0.1mg/L
Ob-0.1mg/L
Ob-0.1mg/L
Final Arsenic
Concentration
0.0028 mg/L
<0.0015mg/L
0.001 mg/L
0.001 mg/L
Precipitate
Arsenic
Concentration
99.96%
recovery of
arsenic
-
-
-
Precipitating Agent
or Process0
Chemical
precipitation and
filtration
Chemical
precipitation and
filtration
Chemically assisted
clarification
Chemical
precipitation
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation
Source
2.31
2.31
2.9
2.9
2.9
2.9
A-12
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
61
62
63
64
65
66
Industry or Site
Type
-
-
-
-
-
Municipal
landfill
Waste or
Media
Wastewater
bearing
unspecified
RCRA listed
waste code
Wastewater
bearing
unspecified
RCRA listed
waste code
Wastewater
bearing
unspecified
RCRA listed
waste code
Hazardous
leachate,
F039
Wastewater
bearing
unspecified
RCRA listed
waste code
Leachate
Scale3
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Site Name
-
-
-
-
-
-
Initial Arsenic
Concentration
0.1 - 1 mg/L
0.1 - 1 mg/L
0.1 - 1 mg/L
0.1 - 1 mg/L
0.1 - 1 mg/L
1 - 10 mg/L
Final Arsenic
Concentration
0.0 12 mg/L
0.0 12 mg/L
0.006 mg/L
0.008 mg/L
0.0 14 mg/L
8 mg/L
Precipitate
Arsenic
Concentration
-
-
-
-
-
-
Precipitating Agent
or Process0
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Chemical
precipitation,
activated carbon
adsorption, and
filtration
Source
d
2.9
2.9
2.9
2.9
2.9
2.9
A-13
-------
Table A. 1
Available Precipitation/Coprecipitation Treatment Performance Data for Arsenic (continued)
Project
Number
67
68
69
Industry or Site
Type
Metals
processing
Metals
processing
Waste or
Media
Scrubber
water from
lead smelter
Thickener
overflow from
lead smelter
Industrial
wastewater
Scale3
Pilot
Pilot
Pilot
Site Name
Initial Arsenic
Concentration
3,300 mg/L
5.8 mg/L
5.8 mg/kg
Final Arsenic
Concentration
0.007 mg/L
0.003 mg/L
< 0.5 mg/kg
Precipitate
Arsenic
Concentration
Precipitating Agent
or Process0
Mineral-like
precipitation
(additional
information not
available)
Mineral-like
precipitation
(additional
information not
available)
Source
2.17
2.17
2.17
a Excluding bench-scale treatments.
b Detection limit not provided.
0 The information that appears in the "Precipitating Agent or Process" column of Appendix A, including the chemicals used, the descriptions of the
precipitation/coprecipitation processes, and whether the process involved precipitation or coprecipitation, is based on the information reported in the cited
references. This information was not independently checked for accuracy or technical feasability. In some cases the term "precipitation" may be applied to a
process that is actually coprecipitation.
d Sources are listed in the References subsection of Section 2.0, Precipitation/Coprecipitation Treatment for Arsenic, on page 21.
e Source did not further identify waste or media.
EPT = Extraction procedure toxicity test
mg/L = milligrams per liter
RCRA = Resource Conservation and Recovery
Act
UV = Ultra violet
gpd = gallons per day
mgd = million gallons per day
TCLP = Toxicity characteristic leaching
procedure
gpm = gallons per minute
mg/kg = milligrams per kilogram
- = Not available
TWA = Total waste analysis
WET = Waste extraction test
A-14
-------
Appendix B
Adsorption Treatment Performance Data for Arsenic
-------
Table B.I
Available Adsorption Treatment Performance Data for Arsenic
Project
Number
Industry or Site
Type
Waste or Media
Scale3
Site Name
Initial Arsenic
Concentration
Final Arsenic
Concentration
Adsorption Process
Description1"
Source
c
Environmental Media - Activated Alumina
1
2
3
4
-
-
-
-
Groundwater
Ground-water
Solution
containing
bivalent arsenic
Solution
containing
pentavalent
arsenic
Full
Pilot
Pilot
Pilot
-
-
-
-
-
-
Trivalent
arsenic,
0.1 mg/L
Pentavalent
arsenic,
0.1 mg/L
<0.05 mg/L
<0.05 mg/L
Trivalent arsenic,
0.05 mg/L
Pentavalent arsenic,
0.05 mg/L
Activated alumina flow
rate: 300 liters/hour
Activated alumina
adsorption at pH 5
Activated alumina
adsorption at pH 6.0 of
solution containing
trivalent arsenic; 300
bed volumes treated
before effluent
exceeded 0.05 mg/L
arsenic
Activated alumina
adsorbent at pH 6.0 of
solution containing
pentavalent arsenic;
23,400 bed volumes
treated before effluent
exceeded 0.05 mg/L
arsenic
3.9
3.4
3.3
3.3
B-l
-------
Table B.I
Available Adsorption Treatment Performance Data for Arsenic (continued)
Project
Number
Industry or Site
Type
Waste or Media
Scale3
Site Name
Initial Arsenic
Concentration
Final Arsenic
Concentration
Adsorption Process
Description1"
Source
c
Environmental Media - Activated Carbon
5
6
7
8
9
10
Wood preserving
Wood preserving
Wood preserving
Wood preserving
Chemical mixing
and batching
Chemical
manufacturing
Groundwater
Groundwater,
27,000 gpd
Groundwater,
3,000 gpd
Groundwater,
4,000 gpd
Groundwater,
43,000 gpd
Groundwater,
65,000 gpd
Full
Full
Full
Full
Full
Full
Mid-South Wood
Product Superfund
Site, Mena, AS
North Cavalcade
Street Superfund
Site Houston, TX
Saunders Supply
Company Superfund
Site, Chuckatuck,
VA
McCormick and
Baxter Creosoting
Co. Superfund Site,
Portland, OR
Baird and McGuire
Superfund Site,
Holbrook, MA
Greenwood
Chemical Superfund
Site, Greenwood,
VA
0.018 mg/L
<0.005mg/L(29of35
monitoring wells)
Treatment train
consisting of oil- water
separation, filtration,
and carbon adsorption;
performance data are for
the entire treatment
train
Treatment train
consisting of filtration
followed by carbon
adsorption
Treatment train
consisting of metals
precipitation, filtration,
and carbon adsorption
Treatment train
consisting of filtration,
ion exchange, and
carbon adsorption
Treatment train
consisting of air
stripping, metals
precipitation, filtration,
and carbon adsorption
Treatment train
consisting of metals
precipitation, filtration,
UV oxidation and
carbon adsorption
3.5
3.7
3.7
3.7
3.7
3.7
B-2
-------
Table B.I
Available Adsorption Treatment Performance Data for Arsenic (continued)
Project
Number
Industry or Site
Type
Waste or Media
Scale3
Site Name
Initial Arsenic
Concentration
Final Arsenic
Concentration
Adsorption Process
Description1"
Source
c
Environmental Media - Iron-Based Media
11
12
Landfill
Groundwater
Ground-water,
3,600 gpd
Pilot
Pilot
CA
0.018 mg/L
0.027 mg/L
<0.002 mg/L
Precipitation from
barite addition followed
by an iron filings and
sand media filter
Fixed-bed adsorber with
sulfur-modified iron
adsorbent; 13,300 bed
volumes put through
unit
3.8,
3.13
3.19
Drinking Water - Activated Alumina
13
14
15
16
17
-
-
-
Drinking water
Drinking water
Drinking water
Drinking water
Drinking water,
14,000 gpd
Full
Full
Full
Full
Full
-
Project Earth
Industries, Inc.
Bow,NH
0.063 mg/L
0.034 -
0.087 mg/L
0.34 mg/L
0.049 mg/L
0.057-
0.062 mg/L
<0.003 mg/L
<0.05 mg/L
0.01 - 0.025 mg/L
<0.003 mg/L
0.050 mg/L
Two activated alumina
columns in series;
media replaced in one
column every 1.5 years
Activated alumina
Activated alumina
Two activated alumina
columns in series;
media replaced in
column tank every 1.5
years
Activated alumina
3.3
3.12
3.8
3.3
3.3
Drinking Water - Iron-Based Media
18
Drinking water
Full
Harbauer GmbH &
Co., Berlin,
Germany
0.3 mg/L
<0.01 mg/L
Granular ferric
hydroxide
3.11
B-3
-------
Table B.I
Available Adsorption Treatment Performance Data for Arsenic (continued)
Project
Number
19
20
21
Industry or Site
Type
-
-
-
Waste or Media
Drinking Water
Drinking water
Drinking water
Scale3
Pilot
Pilot
Full
Site Name
-
-
-
Initial Arsenic
Concentration
0.1- 0.18 mg/L
0.180mg/L
0.02 mg/L
Final Arsenic
Concentration
<0.01 mg/L
0.010 mg/L
0.003 mg/L
Adsorption Process
Description1"
Fixed bed absorber with
ferric hydroxide-coated
newspaper pulp; 20,000
bed volumes treated
before effluent
exceeded 0.01 mg/L
arsenic
Granular ferric
hydroxide
Fixed bed adsorber with
ferric oxide granules
Source
c
3.15
3.16
3.20
Drinking Water - Other or Unknown Media
22
23
-
-
Drinking water
Drinking water
Full
Pilot
-
ADI International
5 mg/L
-
0.01 mg/L
-
Copper-zinc granules
Adsorption in
pressurized vessel
containing proprietary
media at pH 5. 5 to 8.0
3.14
3.1
a Excluding bench-scale treatments.
b Some processes employ a combination of adsorption, ion exchange, oxidation, precipitation/coprecipitation, or filtration to remove arsenic from water.
0 Sources are listed in the References subsection of Section 3.0, Adsorption Treatment for Arsenic, on page 28.
AA = activated alumina
EPT = Extraction procedure toxicity test
mg/L = milligrams per liter
RCRA = Resource Conservation and Recovery
Act
WET = Waste extraction test
gpd = gallons per day
mgd = million gallons per day
TCLP = Toxicity characteristic leaching
procedure
UV = Ultraviolet
mg/kg = milligrams per kilogram
- = Not available
B-4
-------
Appendix C
Ion Exchange Treatment Performance Data for
Arsenic
-------
Tabled
Available Ion Exchange Treatment Performance Data for Arsenic
Project
Number
Industry or Site
Type
Waste or
Media
Scale
Site Name
Ion Exchange
Media or Process
Untreated Arsenic
Concentration
Treated Arsenic
Concentration
Ion Exchange Media
Regeneration
Information
Source
b
Environmental Media
1
2
3
Wood preserving,
spill of chromated
copper arsenate
Waste disposal
Wood preserving
Surface water
Ground-water,
43,000 gpd
Groundwater,
4,000 gpd
Full
Full
Full
Vancouver,
Canada
(site name
unknown)
Higgins
Farm
Superfund
Site,
Franklin
Township,
NJ
McCormick
and Baxter
Creosoting
Co.,
Portland,
OR
Anion and cation
resins
Treatment train
consisting of air
stripping, metals
precipitation,
filtration, and ion
exchange
Treatment train
consiting of
filtration, ion
exchange, and
carbon adsorption
0.0394 mg/L
-
-
0.0229 mg/L
-
-
-
-
-
4.2
4.7
4.7
Drinking Water
4
5
-
-
Drinking
water
Drinking
water
Full
Full
-
-
Solid oxidizing
media filter followed
by an anion-
exchange system
Potassium
permanganate
greensand oxidizing
filter followed by a
mixed bed ion-
exchange system
0.019-
0.055 mg/La
0.040 -
0.065 mg/La
O.005 -
0.080 mg/La
0.003 mg/La
-
Bed regenerated
every 6 days
4.1
4.1
C-l
-------
Tabled
Available Ion Exchange Treatment Performance Data (continued)
Project
Number
6
7
Industry or Site
Type
-
-
Waste or
Media
Drinking
water
Drinking
water
Scale
Full
Full
Site Name
-
-
Ion Exchange
Media or Process
Strongly basic gel
ion-exchange resin
in chloride form
Chloride-form
strong-base resin
anion-exchange
process
Untreated Arsenic
Concentration
0.045 - 0.065 mg/L
-
Treated Arsenic
Concentration
0.0008 -
0.0045 mg/L
0.002 mg/L
Ion Exchange Media
Regeneration
Information
Resin regenerated
every 4 weeks
Spent NaCl brine
reused to regenerate
exhausted ion-
exchange bed
Source
b
4.9
4.8
a Data are for entire treatment train, including unit operations that are not ion exchange.
b Sources are listed in the References subsection of Section 4.0, Ion Exchange Treatment for Arsenic, on page 33.
- = Not available gpd = gallons per day mg/L = milligrams per liter.
NaCl = Sodium chloride
C-2
-------
Appendix D
Membrane Filtration Treatment Performance Data
for Arsenic
-------
Table D.I
Available Membrane Filtration Treatment Performance Data for Arsenic
Project
Number
Media or Waste
Scale
Site Name
Initial Arsenic
Concentration
Percent Arsenic Removal3 or
Final Arsenic Concentration
Membrane or
Treatment Process
Source
Nanofiltration
1
2
3
4
5
6
7
8
9
10
11
Groundwater
Groundwater
Groundwater with low
DOC (Img/L)
Groundwater with high
DOC(llmg/L)
Groundwater with high
DOC(llmg/L)
Arsenic-spiked surface
water
Arsenic-spiked surface
water
Arsenic-spiked surface
water
Arsenic-spiked DI water
Arsenic- spiked lake
water
Arsenic-spiked DI water
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Bench
Bench
Bench
Tarrytown, NY
Tarrytown, NY
-
-
-
0.038 -0.1 54 mg/L
0.038 -0.1 54 mg/L
-
-
-
95%
95%
60%
80%
75% initial,
3- 16% final
Arsenic (III) 20%
Arsenic (V) > 95%
Arsenic (III) 30%
Arsenic (V) > 95%
Arsenic (III) 52%
Arsenic (V) > 95%
Arsenic (III) 12%
Arsenic (V) 85%
Arsenic (V) 89%
Arsenic (V) 90%
NF70
TFCS
Single element,
negatively charged
membrane
Single element,
negatively charged
membrane
Single element,
negatively charged
membrane
Single element
membrane
Single element
membrane
Single element
membrane
Single element,
negatively charged
membrane
Single element,
negatively charged
membrane
Flat sheet, negatively
charged membrane
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
D-l
-------
Table D.I
Available Membrane Filtration Treatment Performance Data for Arsenic (continued)
Project
Number
Media or Waste
Scale
Site Name
Initial Arsenic
Concentration
Percent Arsenic Removal3 or
Final Arsenic Concentration
Membrane or
Treatment Process
Source
Reverse Osmosis
12
13
14
15
16
17
18
19
20
21
22
23
24
Surface water
contaminated with
wood preserving wastes
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater
Groundwater with low
DOC
Groundwater with high
DOC
Arsenic-spiked surface
water
Arsenic-spiked surface
water
Arsenic-spiked surface
water
Arsenic-spiked surface
water
Groundwater
Full
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Pilot
Charlotte Harbor, FL
Cincinnati, OH
Eugene, OR
Fairbanks, AL
Hudson, NH
-
-
-
San Ysidro, NM
24.4 mg/L
-
-
-
-
-
-
-
-
-
Arsenic removal, 99%
reject stream, 57.7 mg/L
treated effluent stream,
0.0394 mg/L
Arsenic (III) 46-84%
Arsenic (V) 96-99%
Arsenic (III) 73%
50%
50%
40%
> 80%
> 90%
Arsenic (III) 60%
Arsenic (V) > 95%
Arsenic (III) 68%
Arsenic (V) > 95%
Arsenic (III) 75%
Arsenic (V) > 95%
Arsenic (III) 85%
Arsenic (V) > 95%
91%
Treatment train
consisting of RO
followed by ion
exchange; performance
data are for RO treatment
only
-
-
-
-
-
Single element,
negatively charged
membrane
Single element,
negatively charged
membrane
Single element
membrane
Single element
membrane
Single element
membrane
Single element
membrane
-
5.1
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
5.4
D-2
-------
Table D.I
Available Membrane Filtration Treatment Performance Data for Arsenic (continued)
Project
Number
25
26
27
28
29
30
31
Media or Waste
Ground-water
Groundwater
Groundwater
Arsenic- spiked lake
water
Arsenic-spiked DI water
Arsenic-spiked DI water
Drinking water
Scale
Pilot
Pilot
Pilot
Bench
Bench
Bench
Pilot
Site Name
San Ysidro, NM
San Ysidro, NM
Tarrytown, NY
-
-
-
Park City Spiro
Tunnel Water
Filtration Plant, Park
City, Utah
Initial Arsenic
Concentration
-
-
-
-
-
-
0.065 mg/L
Percent Arsenic Removal3 or
Final Arsenic Concentration
99%
93-99%
86%
Arsenic (III) 5%
Arsenic (V) 96%
Arsenic (III) 5%
Arsenic (V) 96%
Arsenic (V) 88%
0.0005 mg/L
Membrane or
Treatment Process
Hollow fiber, polyamide
membrane
Hollow fiber, cellulose
acetate membrane
-
-
-
-
Source
5.4
5.4
5.4
5.4
5.4
5.4
5.12
Microfiltration
32
33
Groundwater
Groundwater
Full
Pilot
0.005-3.8mg/L
0.2 -1.0 mg/L
O.005 - 0.05 mg/L
<0.005 mg/L
Iron coprecipitation
followed by membrane
filtration
Iron coprecipitation
followed by ceramic
membrane filtration
5.14
5.13
a Percent arsenic rejection is 1 minus the mass of arsenic in the treated aqueous stream divided by the mass of arsenic in the influent times 100
[(l-(mass of arsenic influent/mass of arsenic effluent)) *100].
b Sources are listed in the References subsection of Section 5.0, Membrane Filtration Treatment for Arsenic, on page 38.
DI = Deionized DOC = Dissolved organic carbon - = Not available
NF = Nanofiltration RO = Reverse Osmosis > = Greater than
TFCS = Thin film composite
D-3
-------
Appendix E
Selected Annotated Bibliography
-------
SELECTED ANNOTATED BIBLIOGRAPHY
E. 1 E-mail attachment sent from Doug Sutton,
Geotrans, Inc., to Linda Fiedler, U.S. EPA. April
20, 2001. - The e-mail attachment discusses sites
that are treating arsenic contamination with pump-
and-treat technologies. In addition, the e-mail
attachment includes site summaries for two sites
using ion exchange. The purpose of the e-mail
attachment is to provide site-specific information
for sites treating arsenic contamination.
E.2 U.S. EPA. Office of Research and Development.
Environmental Technology Verification Program
(ETV). Reverse Osmosis Membrane Filtration
Used In Packaged Drinking Water Treatment
Systems. March 2001.
http://www.membranes.com - This document
discusses verification testing of a reverse osmosis
unit used to treat arsenic-contaminated
groundwater. In addition, the document includes
test results for the reverse osmosis module. The
purpose of the document is to verify the
performance of the reverse osmosis technology
for removing arsenic from groundwater.
E.3 Murcott, S. Appropriate Remediation
Technologies for Arsenic-Contaminated Wells in
Bangladesh. Massachusetts Institute of
Technology. February 1999. - This presentation
discusses ion exchange as one option for treating
arsenic-contaminated groundwater in Bangladesh.
In addition, this presentation includes
information on various other technologies. The
purpose of the presentation is to emphasize the
use of low-cost technologies that may be
implemented to treat arsenic-contaminated water
in Bangladesh.
E.4 Tidwell, L.G., et al. Technologies and Potential
Technologies for Removing Arsenic from Process
and Mine Wastewater. Presented at
"REWAS'99." San Sebastian, Spain. September
1999. - This presentation discusses technologies
(including adsorption) being used or that may be
used to treat arsenic in mine waters. In addition,
the presentation includes descriptions of and
results for demonstration studies. The purpose of
the presentation is to provide information on the
removal of arsenic from mine waters.
E.5 U.S. EPA. Office of Research and Development.
Arsenic & Mercury - Workshop on Removal,
Recovery, Treatment, and Disposal.
EPA-600-R-92-105. August 1992 - These abstract
proceedings discuss treatment technologies
(including ion exchange, membrane filtration, and
precipitation/coprecipitation) for treating
arsenic-contaminated wastes. In addition, the
proceedings include information on fundamentals;
analytical techniques/ characterization; and
removal, recovery, and reuse. The purpose of the
proceedings is to highlight the technical
presentations of the workshop, which provided a
forum for discussing arsenic.
E.6 U.S. EPA. Office of Ground Water and Drinking
Water. Arsenic in Drinking Water Rule Economic
Analysis. EPA 815-R-00-026. December 2000.-
This document discusses the impacts of the
revised Arsenic Rule, which reduces the maximum
contaminant level for arsenic in community water
systems from 0.050 mg/L to 0.010 mg/L. In
addition, the document also includes baseline,
benefits, cost, and economic analyses. The
purpose of the document is to estimate the costs
and benefits associated with the revised Arsenic
Rule.
E.7 U.S. EPA. Arsenic Removal from Drinking Water
by Coagulation/Filtration and Lime Softening
Plants. EPA/600/R-00/063. Office of Research and
Development. June 2000 - This report discusses
the design and operation of three treatment plants
with arsenic-contaminated influent. In addition,
the report includes the results of analyses
performed on water and residual samples collected
at each treatment facility. The purpose of the
report is to evaluate the effectiveness of
conventional coagulation/ flocculation and lime
softening to consistently reduce arsenic
concentrations in source water to low levels.
E.8 U.S. EPA. Office of Research and Development.
Arsenic Removal from Drinking Water by Ion
Exchange and Activated Alumina Plants. EPA
600-R-00-088. October 2000. - This report
discusses design and operation of two activated
alumina treatment plants and two ion exchange
E-l
-------
treatment plants with arsenic in the source
water. In addition, the report includes data on
samples and residuals collected from the
treatment plants. The purpose of the report is
to evaluate the ability of these systems to
consistently reduce arsenic concentrations in
source water to low levels.
E.9 U.S. EPA. Office of Solid Waste. Best
Demonstrated Available Technology (BDAT)
Background Document for Wood Preserving
Wastes: F032, F034, and F035; Final. April 1996 -
This background document discusses
technologies (including
precipitation/coprecipitation) used to treat wood
preserving wastes. In addition, the document
discusses U.S. EPA's technical support and
rationale for developing regulatory standards for
such wastes. The purpose of the document is to
present the development of new treatment
performance standards as BDAT for wood
preserving wastes.
E.10 U.S. EPA. Office of Water. Development
Document for Effluent Limitations Guidelines and
Standards for the Centralized Waste Treatment
Industry. December 2000. - This document
discusses the effluent limitations guidelines and
standards for the centralized waste treatment
industry. In addition, the document describes
wastewater treatment technologies (including
precipitation/ coprecipitation). The purpose of
the document is to provide the technical bases for
the final effluent limitations guidelines,
pretreatment standards, and new source
performance standards for the centralized waste
treatment industry point source category.
E. 11 U.S. EPA. Office of Solid Waste. Final Best
Demonstrated Available Technology (BDAT)
Background Document for K031, K084, K101,
K102, Characteristic Arsenic Wastes (D004),
Characteristic Selenium Wastes (DO 10), and P and
U Wastes Containing Arsenic and Selenium
Listing Constituents. May 1990 - This
background document discusses technologies
(including adsorption, ion exchange, and
precipitation/coprecipitation) used to treat
arsenic-containing wastes. In addition, the
document discusses U.S. EPA's technical support
and rationale for developing regulatory standards
for such wastes. The purpose of the document is
to present the development of new treatment
performance standards as BDAT for
arsenic-containing wastes.
E.12 U.S. EPA. Office of Research and Development.
Regulations on the Disposal of Arsenic Residuals
from Drinking Water Treatment Plants.
EPA/600/R-00/025. May 2000. - This report
discusses water treatment processes (including
adsorption, ion exchange, and membrane
filtration) known to be effective in removing
arsenic from small groundwater systems and
characteristics of the residuals produced. In
addition, the report includes regulations
applicable to these residuals. The purpose of the
report is to summarize federal regulations and
selected state regulations that govern the
management of residuals produced by treatment
systems removing arsenic from drinking water.
E. 13 U.S. EPA. Technologies and Costs for Removal
of Arsenic From Drinking Water. EPA-R-00-028.
Office of Groundwater and Drinking Water.
December 2000. - This document discusses
arsenic removal technologies (including
adsorption, ion exchange, membrane filtration, and
precipitation/coprecipitation) and technology
costs. In addition, the document discusses
residuals handling, disposal alternatives, and
point-of-entry/ point-of-use treatment options.
The purpose of the document is to provide cost
information on removing arsenic from drinking
water.
E. 14 U.S. EPA. Office of Solid Waste and Emergency
Response. Arsenic Treatment Technologies for
Soil, Waste, and Water. EPA-542-R-02-004.
Publication expected June 2002. - This report
contains information on the current state of the
treatment of soil, waste, and water containing
arsenic, which can be difficult to treat and may
cause a variety of adverse health effects in
humans. By summarizing information on the
treatment of arsenic, identifying sites and facilities
where particular arsenic treatment technologies
have been used in the past, and acting as a
reference to more detailed arsenic treatment
information, this report promotes the transfer of
information on innovative and established
technologies for arsenic treatment.
E-2
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