United States
Environmental Protection
Agency,
Office of Research and
Development
Washington, DC 20460
EPA/600/R-00/025
May 2000
http://www.epa.gov
Regulations on the
Disposal of Arsenic
Residuals from Drinking
Water Treatment Plants
If"
As (I Ilk;
As(V)
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EPA/600/R-00/025
May 2000
Regulations on the Disposal of Arsenic
Residuals from Drinking Water Treatment Plants
by
Science Applications International Corporation
Reston, Virginia 20190
EPA Contract 68-C7-0011
Work Assignment 0-38
Work Assignment Manager
Thomas J. Sorg
Water Supply and Water Resources Division
National Risk Management Research Laboratory
Cincinnati, OH 45268
National Risk Management Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
Printed on Recycled Paper
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Disclaimer
The information in this document has been funded wholly or in part by the U.S.
Environmental Protection Agency. It has been subjected to the Agency's peer and ad-
ministrative review, and it has been approved for publication as an EPA document.
Mention of trade names or commercial products is for explanatory purpose only, and
does not constitute endorsement or recommendation for use.
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Foreword
The U.S. Environmental Protection Agency is charged by Congress with protecting the
Nation's land, air, and water resources. Under a mandate of national environmental
laws, the Agency strives to formulate and implement actions leading to a compatible
balance between human activities and the ability of natural systems to support and
nurture life. To meet this mandate, EPA's research program is providing data and tech-
nical support for solving environmental problems today and building a science knowl-
edge base necessary to manage our ecological resources wisely, understand how pol-
lutants affect our health and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for inves-
tigation of technological and management approaches for reducing risks from threats
to human health and the environmental. The focus of the laboratory's research pro-
gram is on methods for the prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation
of contaminated sites and ground water; and prevention and:control of indoor air. The
goal of this research effort is to catalyze development and implementation of innova-
tive, cost-effective environmental technologies; develop scientific and engineering in-
formation needed by EPA to support regulatory and policy decisions; and provide tech-
nical support and information transfer to ensure effective implementation of environ-
mental regulations and strategies.
This publication has been produced as part of the Laboratory's strategic long-term re-
search plan. It is published and made available by EPA's Office of Research and Devel-
opment to assist the user community and to link researchers With their clients.
T. Timothy Oppelt, Director
National Risk Management Research Laboratory
in
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Abstract
As with other production processes, water treatment systems produce a product and a
residual of that product. With the passage of the various federal statues, restrictions have
been placed on the discharge of residuals to water bodies and onto land. This report sum-
marizes federal regulations and selected state regulations that govern the management of
residuals produced by small drinking water treatment systems removing arsenic from drinking
water.
Arsenic is a naturally occurring contaminant in ground water and many small water treat-
ment facilities use ground water as their primary source of water. Under the Safe Drinking
Water Act (SDWA), a maximum contaminant level (MCL) of 0.05 mg/L has been estab-
lished for arsenic in drinking water. Under the 1996 SDWA Amendments, the EPA is re-
quired to develop a revised arsenic regulation by January 2001. Concerns have been raised
as to the technical feasibility and regulatory implication of a more stringent arsenic MCL on
the disposal of the residuals from arsenic removal processes.
This document reports on five water treatment processes known to be effective for arsenic
removal from small ground water systems. The five processes are anion exchange, acti-
vated alumina adsorption, iron/manganese removal, media adsorption, and membrane pro-
cesses. For each technology, a brief description is provided of the treatment process along
with a discussion of the residual production characteristics.
An overview is provided of the federal regulations that apply to the management of residu-
als, with a focus on arsenic removal residuals. The purpose of this overview is to provide
guidance to water suppliers on the federal regulatory requirements of residuals manage-
ment to better evaluate compliance of existing practices and to plan for needed changes in
treatment plant operations. Specific disposal methods are summarized by the form of the
residuals including liquid residuals (direct discharges, indirect discharges, underground
injection, and land disposal) and solid/sludge residuals (solid waste landfill, hazardous
water landfill, lagoons, reuse of hazardous waste, reuse of solid waste, and off-site dis-
posal) and the method in which the residuals are managed. Federal regulations summa-
rized include the Clean Water Act (NPDES, Pretreatment), SDWA (Underground Injection
Control and lagoons), and Resource Conservation and Recovery Act (Subtitles C/D).
In addition to the federal regulations that impact the management of arsenic drinking water
treatment residuals, regulations imposed by seven states were also reviewed. The seven
states (Arizona, California, Maine, Nebraska, New Mexico, Nevada, and Pennsylvania)
were chosen based on arsenic occurrence and regional representation. The review of the
state regulations also focused on characterizing the requirements that apply to different
management options available for liquid and solid residuals generated by treatment sys-
tems that remove arsenic from drinking water. It was found that many components of the
state regulatory programs were generally consistent with the federal minimum require-
ments. However, the state programs differed from federal program requirements and each
other in several aspects including surface water quality standards applicable to control the
amount of arsenic in direct discharges of liquid effluent, the local limits that specify how
much arsenic may be discharged to a sanitary sewer system, the regulation of solid waste
landfills, the protection of ground water resources, and the regulation of land application
activities.
IV
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Contents
Foreword jjj
Abstract jv
Figures ;. vii
Tables viij
Acronyms, Abbreviations, and Symbols ix
1. Introduction 1
2. Arsenic Removal Technologies for Small Systems 2
2.1 Anion Exchange I!.'.".".""."! 2
2.1.1 Process Description [" 2
2.1.2 Residual Generation and Disposal I!!!.'""!!."""."]!!"" 3
2.2 Activated Alumina 3
2.2.1 Process Description ""!"!.'"" 3
2.2.2 Residual Generation and Disposal '.". 4
2.3 Media Adsorption , ""'4
2.3.1 Process Description 4
2.3.2 Residual Generation and Disposal 4
2.4 Iron/Manganese Removal Methods .'!!!".'."!!""".'.' 6
2.4.1 Process Description ".'.'.'.'.'.'.'.'.'.'. 6
2.4.2 Residual Generation and Disposal 7
2.5 Membrane Processes .'.'"!!.'."!!!" 7
2.5.1 Process Description 7
2.5.2 Residual Generation and Disposal 7
2.6 Summary of Treatment Technologies !!."."!.""."".'."."!.'."!!!!! 8
3. Federal Statutory and Regulatory Requirements 10
3.1 Key Factors in Identifying Applicable Federal Regulations "". 10
3.2 Liquid Residuals '" -\Q
3.2.1 Direct Discharge: CWANPDES !!"!"""!"!"!!"!""! 10
3.2.2 Indirect Discharge: CWA Pretreatment 12
3.2.3 Underground Injection: SDWAUIC "'. 12
3.2.4 Land Disposal: RCRA Subtitles C/D 13
3.3 Solid/Sludge Residuals 13
3.3.1 Solid Waste Landfill: RCRA Subtitle D ."". 13
3.3.2 Hazardous Waste Landfill: RCRA Subtitle C '.'. 14
3.3.3 Lagoons: SDWA 14
3.3.4 Reuse of Hazardous Waste: RCRA Subtitle C I!!!!!."!!""!!"!!."" 15
3.3.5 Reuse of Solid Waste: RCRA Subtitle D ; 15
3.3.6 Off-Site Disposal 15
4. Select State Regulatory Requirements 16
4.1 Liquid Residuals \"" -\Q
4.1.1 Direct Discharge to Surface Waters I..""!!!.'""!.'."." 16
4.1.2 Indirect Discharges to a Sanitary Sewer System 17
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4.1.3 Underground Injection 18
4.1.4 Land Disposal }8
4.2 Solid/Sludge Residuals ]°
4.2.1 Solid Waste Landfills 18
4.2.2 Hazardous Waste Landfills 18
4.2.3 Lagoons ^j8
4.2.4 Reuse (Land Application) 19
4.2.5 Off-Site Disposal 19
4.3 Arizona ]^
4.3.1 Liquid Residuals 19
4.3.2 Solid/Sludge Residuals 22
4.4 California 23
4.4.1 Liquid Residuals 23
4.4.2 Solid/Sludge Residuals - 25
4.5 Maine 2°
4.5.1 Liquid Residuals 2°
4.5.2 Solid/Sludge Residuals 27
4.6 Nebraska 2|
4.6.1 Liquid Residuals 2°
4.6.2 Solid/Sludge Residuals 29
4.7 New Mexico 31
4.7.1 Liquid Residuals 3jl
4.7.2 Solid/Sludge Residuals 32
4.8 Nevada 33
4.8.1 Liquid Residuals 33
4.8.2 Solid/Sludge Residuals 34
4.9 Pennsylvania 35
4.9.1 Liquid Residuals 35
4.9.2 Solid/Sludge Residuals 36
5. References 38
VI
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Figures
Page
2-1 Schematic of Ion Exchange Process with Upflow Regeneration 3
2-2 Schematic of Activated Alumina Process with Regeneration 5
2-3 Schematic of Media Adsorption 5
2-4 Schematic of Oxidation-Filtration Fe/Mn Removal Process 6
2-5 Schematic of Greensand Media Treatment Process 7
2-6 Schematic of Membrane Filtration Process 8
3-1 Federal Regulations Governing the Disposal of Residuals 11
VII
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Tables
Page
2-1 Summary of Residuals/Management Methods 9
4-1 Summary of Federal Recommended and Select State Surface Water Quality
Standards for Arsenic 17
4-2 Examples of Arsenic Local Limits for Selected States 18
4-3 Select State Arsenic Ground Water Quality Standards 20
4-4 Select State Land Application Standards for DWTP Sludge 21
4-5 Arizona's Designated Use Numeric Arsenic Surface Water
Quality Standards 22
4-6 California Toxics Rule Proposed Surface Water Quality Standards 24
4-7 Arsenic Surface Water Quality Standards in California Regional
Basin Plans 24
4-8 Maine's Numeric Arsenic Surface Water Quality Standards 27
4-9 Nebraska's Designated Use Numeric Arsenic Surface Water Quality
Standards 29
4-10 New Mexico's Designated Use Numeric Arsenic Surface Water Quality
Standards 32
4-11 Nevada's Designated Use Numeric Arsenic Surface Water Quality Standards 34
4-12 Pennsylvania's Arsenic Surface Water Quality Criteria 36
VIII
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Acronyms, Abbreviations, and Symbols
AA
AAC
As
BAT
BPJ
CESQG
CFR
CTR
CWA
DEP
DWTP
EPA
Fe
GFH
HMTA
LDR
LOG
LTU
MAHL
MCL
Mn
MSWLF
NAG
NMAC
NPDES
PAC
PCBs
PCS
POTW
psi
RCRA
RWQCB
SDWA
SIC
SQG
SWRCB
TCLP
IDS
TFCH
TOC
TSDF
UIC
WET
WDR
Activated alumina
Arizona Administrative Code
Arsenic
Best available technology
Best professional judgement
Conditionally exempt small quantity generators
Code of Federal Regulations
California Toxics Rule
Clean Water Act
Department of Environment Protection
Drinking water treatment plant
U.S. Environmental Protection Agency
Iron
Granular ferric hydroxide
Hazardous Materials Transportation Act
Land disposal restrictions
Large quantity generators
Land treatment unit
Maximum allowable headworks loading
Maximum contaminant level
Manganese
Municipal solid waste landfills
Nevada Administrative Code
New Mexico Administrative Code
National Pollutant Discharge Elimination System
Pennsylvania Administrative Code
Polychlorinated biphenyls
Permit Compliance System
Publicly owned treatment works
Pound per square inch
Resource Conservation and Recovery Act
Regional Quality Control Board
Safe Drinking Water Act
Standard industrial classification
Small quantity generators
State Water Resource Control Board
Toxicity characteristics leaching procedure
Total dissolved solids
Treated formerly characteristic hazardous wastes
Total organic carbon
Treatment, storage, disposal facilities
Underground Injection Control
Waste extraction test
Waste discharge requirements
IX
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1. Introduction
Water treatment systems, as with other production pro-
cesses, create two types of materials - a product and re-
siduals of that product. Historically, much of the technical
and regulatory focus has been on the quality of the prod-
uct, treated water, with little attention paid to residuals. This
lack of attention was due, in part, to the general percep-
tion by the water industry of the innocuous nature of water
treatment residuals and the lack of clear regulations re-
garding residuals disposal. Since the passage of the Clean
Water Act (CWA) and other federal environmental statutes
in the 1970s, restrictions have been placed on the dis-
charge of residuals to water bodies and onto the land. Water
quality standards are covering a greater number of con-
taminants and are being continuously reviewed for their
sufficiency in protecting the environment. Therefore, wa-
ter utilities and regulators need to continually evaluate and
reconsider standard practices for managing residuals. To
assist in this evaluation, this report has been developed to
summarize federal regulations and selected state regula-
tions that govern the management of residuals produced
by treatment systems removing arsenic from drinking wa-
ter. The focus of this report is on systems used primarily
by small water facilities.
In 1975, U.S. Environmental Protection Agency (EPA) es-
tablished a maximum contaminant level (MCL) for arsenic
at 0.05 mg/L in drinking water. Since that time, reductions
to the MCL have been considered, but no changes have
been made. In 1996, amendments to the Safe Drinking
Water Act (SDWA) required EPA to develop an arsenic
research plan, a proposal to revise the MCL by January
2000, and a final rule by January 2001. In comments on
the draft research plan, EPA's Board of Scientific Advisors
raised concerns about both technical feasibility and regu-
latory implications of a more stringent arsenic MCL on the
disposal of the residuals from arsenic removal treatment
processes.
Many water treatment facilities, particularly small systems,
use ground water as their primary source of drinking wa-
ter. With arsenic being a common, naturally occurring con-
taminant in ground water, it is anticipated that many of these
facilities will be installing arsenic removal processes after
the arsenic MCL is revised. Of the processes that are known
to be effective for arsenic removal, at least five are consid-
ered small ground water system processes: anion ex-
change, activated alumina absorption, iron/manganese
removal, media adsorption, and membrane processes.
Section 2 of the report presents a brief summary of these
five unit processes. The section includes brief descriptions
of the treatment process, residual production, and existing
schematics. Drawing upon this information, Section 3 sum-
marizes federal regulatory requirements and includes a
flow chart depicting major forms of residuals, management
options, and associated regulations. Section 4 presents
select state regulatory provisions that potentially affect the
disposal and management of arsenic drinking water treat-
ment residuals.
Recognizing the variability of levels of arsenic in source
water and efficiencies at individual treatment plants, the
report provides generalized comments on federal regula-
tions that may apply. For example, the report does not pro-
vide specific guidance for each unit process discussed,
but instead provides guidance based on residual form and
management measure. It is recommended that manage-
ment decisions be based on accurate and timely testing of
residual materials.
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2. Arsenic Removal Technologies for Small Systems
Arsenic can be found at varying levels in source waters,
and has both natural and anthropogenic sources. Under
certain conditions, high levels of arsenic can be caused
by leaching of certain rock formations or geothermal ac-
tivity. In addition, human activities such as nonferrous
mining and smelting operations, wood preservative use,
and contaminated pesticide manufacturing sites, can be
the sources of elevated arsenic in drinking water. Another
source of arsenic in drinking water supplies can result from
extensive pesticide use (AWWA, ASCE, 1998). In a re-
cent survey, it was projected that approximately 15 per-
cent of the U.S. population is exposed to arsenic in drink-
ing water at levels greater than 2 jig/L. Most of the high
levels of arsenic (greater than 80 ng/L) are found in ground
water sources, primarily within isolated areas in the west-
em United States.
In water, arsenic typically occurs in one of two inorganic
forms, the pentavalent arsenate, As(V), and the trivalent
arsenite, As(lll). Arsenic converts between these two va-
lence states in response to the relative oxidative or re-
ductive nature of the waters, with arsenite being more
common in waters that are anaerobic or with low levels of
dissolved oxygen. The difference in the charge between
arsenate and arsenite has a significant effect on the ease
of removing arsenic from drinking water, with arsenite, a
weak acid, being generally more difficult to remove
(USEPA, 1993).
The remaining portions of this chapter provide a brief over-
view of five small system unit processes used to remove
arsenic. The processes include anion exchange, activated
alumina treatment, iron/manganese removal, media ad-
sorption, and membrane processes. The information is
based on the removal of arsenate, As(V). Because As(V)
is more readily removed from water than As(lll), pretreat-
ment using oxidants such as chlorine (CL or potassium
permanganate (KMnO4) to oxidize As(lll) to As(V) will likely
be necessary to ensure efficient arsenic removal when
the source water contains predominantly As(III). Oxida-
tion reactions using these oxidants occur rapidly and work
well within a pH range of 6.5 to 9.5 (AWWA, 1990; AWWA,
ASCE, 1998), as long as the concentration of other oxi-
dizable substances such as total organic carbon (TOG) is
low.
2.1 Anion Exchange
2.1.1 Process Description
Anion exchange is the term used to describe the ion ex-
change process which replaces undesirable ions in water,
such as arsenate, with another ion of like charge in a chemi-
cally equivalent amount. To remove these soluble forms of
arsenic, anionic exchange resins (salt-based resins or
strongly basic resins) are used. For example, for arsenate
anion exchange, a resin that is regenerated with sodium
chloride can be used. The resin is packed into a column
and as contaminated water is passed through the resin,
the arsenate ions, As(V), are exchanged for chloride ions
(CI-). Arsenite is generally not removed by ion exchange
(AWWA, 1990; AWWA, ASCE, 1998). A simplified sche-
matic of the ion exchange process with upflow regenera-
tion is shown in Figure 2-1.
Anion exchange is currently an EPA-identified best avail-
able technology (BAT) for the removal of As(V). The re-
moval efficiency of arsenic from influent water depends on
many factors. Ideally, in anion exchange, a non-contami-
nant ion such as chloride or hydroxide is exchanged for a
target contaminant. The effluent water from the ion ex-
change column will have a concentration of chloride ions
equal to the concentration of all the anions replaced by
the chloride including the sulfate and arsenate anions in
the influent water (AWWA, 1990; AWWA, ASCE, 1998).
Sulfate has a stronger attraction to anion resins and is
exchanged more readily than arsenic in any form (Hecht
et al., 1993; Vagliasindi and Benjamin, 1997; ASCE,
AWWA, 1998). Sulfate, as well as some negatively charged
organic materials, reduce the arsenic exchange removal
capacity and can cause resin fouling. Research has indi-
cated that arsenate effluent concentrations of less than 2
ng/L can be achieved using ion exchange (Vagliasindi and
Benjamin, 1997).
Because anion exchange is an adsorption process, the
ion resin must be regenerated after its removal capacity
has been exhausted. If the ion exchange process is oper-
ated beyond its resin capacity, the unwanted ions begin to
leak through the resin (AWWA, ASCE, 1998). As the con-
centration of unwanted ions reach unacceptable levels, the
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Raw Water
Source
Pre-Filter
Ion Exchange Column
1
Spent Backwash/
Rinse
Anion Exchange
Resin
I
Spent Regenerant
(Brine)
[To Waste
Disposal]
Backwash/Rinse
Product/Treated
Water
;T
I
Regenerant
Regeneration streams
Figure 2-1. Schematic of ion exchange process with upflow regeneration.
resin must be regenerated. Regeneration of a resin oc-
curs in a three step process - backwashing, regeneration
with brine, and a final rinsing (slow and fast rinse).
Backwashing is an upflow rinse performed to expand the
resin bed and remove any particles. The bed is then con-
tacted by upflow or downflow stream with the regenerant
solution. The flowrate of regenerant is lower than the
flowrate of backwashing, and therefore the contact time is
longer. The regenerant solution is generally sodium chlo-
ride. Finally, the column is rinsed upflow or downflow to
displace the regenerant.
2.1.2 Residual Generation and Disposal
A liquid and solid residual may be generated from an an-
ion exchange system. The liquid residual consists of the
backwash water, regenerant solution, and rinse water.
These waters constitute 1.5 to 10 percent of the treated
water volume depending on the feed water quality and type
of ion exchange unit used (DPRA, 1993). The chemical
composition of ion exchange brines varies as a function of
regenerant dose and concentration, rinsing procedures,
and exchange capacity of the resin (USEPA, 1996). The
spent regenerant may contain high levels of arsenic or have
a corrosive characteristic and therefore subject to strin-
gent disposal and management requirements under CWA
and the Resource Conservation and Recovery Act (RCRA).
Spent resin will be produced when the resin can no longer
be regenerated, or when it becomes poisoned or contami-
nated. Spent resin for disposal may be subject to hazard-
ous waste regulations depending upon the results of a
Toxicity Characteristic Leaching Procedure (TCLP) test.
2.2 Activated Alumina
2.2.1 Process Description
Activated alumina (AA) is an inorganic sorbent that is used
to remove arsenate and its arsenic adsorption capacity is
pH dependent. In the activated alumina process, influent
water is sent through a column packed with activated alu-
mina where the arsenic ions are adsorbed onto the alu-
mina. In this way, the activated alumina process is similar
to the anion exchange process. Exhausted activated alu-
mina may be regenerated on-site, much like ion exchange
resins, or it may be used to exhaustion and replaced with
new media.
The arsenic removal capacity of AA is dependent on the
influent concentration of As(V), pH, and the flow rate
through the contactor (AWWA, 1990). Activated alumina
is available in different mesh sizes and its particle size af-
fects the removal efficiency. Fine-mesh alumina can treat
more bed volumes of water and have higher arsenic re-
moval capacities and a more rapid uptake of As(V) than
coarse-mesh alumina (Montgomery, 1985).
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Regeneration of the treatment bed is required when the
arsenic effluent concentrations reach unacceptable levels.
Regeneration is a four-step process. During this process,
the alumina bed is backwashed, regenerated, neutralized,
and rinsed before being placed back in operation. Sodium
hydroxide is the most common regenerant and sulf uric acid
is typically used to neutralize or condition the bed (USEPA,
1993).
Backwashing is an upflow rinse performed to expand the
activated alumina bed and remove particles. Then the bed
is contacted in an upflow or downflow stream with a caus-
tic solution, the regenerant, which is usually a sodium hy-
droxide solution. The flowrate of regenerant is lower than
the flowrate of backwashing, and therefore the contact time
is longer. The next step is neutralization, which is performed
to return the bed to its operating pH (acidic condition). The
bed is neutralized by rinsing out the excess caustic, then
rinsing the bed column with an acid solution, and finally
rinsing the bed again while monitoring the effluent pH until
it returns to the desired level (Montgomery, 1985). A sim-
plified schematic of the activated alumina process with
regeneration is shown in Figure 2-2.
2.2.2 Residual Generation and Disposal
A liquid and/or solid residual may be produced from an AA
system depending on the type of operation. If the system
is regenerated, a liquid waste is produced from the back-
wash, caustic regeneration, neutralization, and rinse steps.
In some instances, a sludge may be generated from the
regeneration and neutralization streams because some
alumina dissolves during the regeneration step and may
be precipitated as aluminum hydroxide (AWWA, 1990;
USEPA, 1993)
If an aluminum based sludge is produced because of low-
ering the pH of the liquid residual, this sludge will contain a
high amount of arsenic because of its arsenic adsorption
characteristics. This sludge and the remaining liquid frac-
tion of the solution will require disposal. Because both re-
siduals contain arsenic, their disposal may be subject to
the disposal requirements under CWA and RCRA. When
the AA has reached the end of its useful life, the media
itself will also become a solid residual that must be dis-
posed.
Because of its high arsenic removal capacity, an activated
alumina system may be operated on a media throw-away
basis rather than a media regeneration basis. When oper-
ated on a throw-away basis, the exhausted AA media will
be the principal residual produced. This media has the po-
tential of being classified as a hazardous waste because
of its high arsenic content. ATCLP test is necessary, there-
fore, to determine its classification and ultimate disposal
restrictions.
Because the AA media will filter out particulate material in
the source water, the media bed will occasionally require
backwashing. This backwash water will likely contain some
arsenic attached to either the particulate material or the
very fine AA material that is removed during backwashing.
Consequently, the disposal of the backwash water may
also be subject to the disposal requirements under the CWA
and RCRA.
2.3 Media Adsorption
2.3.1 Process Description
During the past five years, several new adsorption media
have been developed with effective arsenic removal effi-
ciencies. Because these media have been recently devel-
oped, their implementation has been very limited to date.
Operationally, media adsorption is very similar to anion
exchange and activated alumina applications. Some me-
dia applications may be used on a one-time throw-away
basis, while others may be regenerated.
With this technology, contaminated water is passed through
a bed of the specially developed media, where arsenic is
adsorbed and removed from the water. One study pre-
sented data using granular ferric hydroxide (GFH) as an
adsorbent for arsenate As(V) removal. (Driehaus et al.,
1998). The results of this study indicate that arsenate lev-
els in the effluent were reduced to 10 |j,g/L from as high as
180 [ig/L in the influent. The effective capacity of GFH will
depend on pH and concentration of phosphate in the influ-
ent. This study suggests that the media may be regener-
ated but recommends disposal of spent GFH as a waste.
A proprietary technology from ADI International (Canada)
uses ADI Media G2 to remove arsenic, lead, copper,
and uranium (see www.adi.ca/Limited/WTARS.HTM). This
system utilizes a pressure vessel containing ADI Media
G2 where arsenic-bearing water passes downward
through the filter where the media adsorbs arsenic and
other metals. It performs over a pH range of 5.5 to 8.0 and
is unaffected by high concentrations of sulfates or chlo-
rides. The pressure drop through the vessel is typically
less than 2 psi. According to the literature, this media can
be regenerated; however, no operational details are pro-
vided. ADI states that the total regeneration volume is less
than 0.1 percent of the volume of water treated. A simpli-
fied schematic of the media adsorption process is pre-
sented in Figure 2-3.
2.3.2 Residual Generation and Disposal
Two general types of residuals are potentially generated
from media adsorption: spent media and regeneration
solution(s). Spent media will be generated from systems
that use the media on a one-time throw-away basis, or
from systems where the media has become exhausted
and can no longer be regenerated, or is no longer effec-
tive. In some cases, depending on manufacturer policy,
spent media may be sent back to the vendor for reactiva-
tion, recovery, or disposal.
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Sulfuric Acid
Rinse
Raw Water
Feed
Backwash
Sodium Hydroxide
:ide I
Activated Alumina
Waste
- Spent Backwash
- Spent Regenerant
Sodium Hydroxide
Product/Treated
Water
Waste
- Spent Acid
- Spent Rinse
Regeneration streams
Figure 2-2. Schematic of activated alumina process with regeneration.
Raw
Water
Backwash/Rinse
Regenerant
Solution
Media
Spent Backwash/
Rinse
Spent Regenerant
Product/Treated
Water
Regeneration streams
Figure 2-3. Schematic of media adsorption.
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Although no details were provided for regeneration, it is
assumed that the same steps as for ion exchange will be
utilized: backwash, regeneration, and rinse. Each of these
steps will generate an aqueous residual which will likely
be combined. Some of the new adsorption media have
such large arsenic removal capacities that periodic
backwashing (with regeneration) is required to remove the
particulate material that is filtered out during its treatment
operation. This backwash water will likely contain some
arsenic that is attached to the particulate material or any
very fine adsorption media that is removed by the
backwashing process. The waste stream is a residual that
may be disposed of immediately at the time of backwashing
or it may be held and disposed with the regeneration waste
water. Depending on the concentration of arsenic in the
influent and other factors, the disposal of the regeneration
waste and the backwash water may be subject to the dis-
posal requirements under CWA and RCRA.
2.4 Iron/Manganese Removal Methods
2.4.1 Process Description
Because arsenic, particularly arsenate, is readily adsorbed
onto iron hydroxide, iron/manganese removal processes
are known to be effective for arsenic removal. One study
showed arsenate reductions from 200 ng/L to less than 5
fxg/L (Lauf and Waer, 1993). Figure 2-4 presents a simpli-
fied schematic of a common air oxidation-filtration iron/
manganese removal water treatment process. The oxida-
tion step converts the soluble iron (ferrous) into the in-
soluble form (ferric) that is then removed by the filtration
process, usually a granular media. Because air oxidation
is not normally effective for oxidizing As(lll) to As(V), chlo-
rine or other oxidant may be required on source waters
that contain As(lll). When the filtration media reaches its
filtering capacity, the media is backwashed producing a
liquid residual (i.e., backwash water) for disposal.
The use of potassium permanganate, in conjunction with
a manganese greensand filter, is also a widely used tech-
nology for removing iron and manganese from water. Po-
tassium permanganate can be fed continuously ahead of
the filter to oxidize As(lll) to As(V) and the iron and manga-
nese which are then adsorbed on the greensand. The po-
tassium permanganate also regenerates the manganese
greensand. Alternatively, the bed of greensand may be
activated intermittently with permanganate to form an ac-
tive coating of manganese dioxide. Because the arsenic
removal process is adsorption onto the iron, the capacity
for arsenic removal is dependent on the concentration of
iron in the source water. The greensand filters also require
periodic backwashing to remove excess solids. A simpli-
Raw
Water
Aeration
CI2
1
(Optional)
Filtration
Figure 2-4. Schematic of oxidation-filtration Fe/Mn removal process.
-------
fied schematic of a greensand filtration process is pre-
sented in Figure 2-5.
Other promising technologies that utilize oxidation and pre-
cipitation/filtration include electrochemical iron addition and
chemical oxidation (Brewster, 1992), and addition of fer-
rate to precipitate ferric arsenate (Johnson, undated).
2.4.2 Residual Generation and Disposal
Iron/manganese removal processes, both the oxidation/
filtration and the potassium permanganate greensand tech-
niques, produce a liquid residual from the filter backwashing
step. Occasionally, the filter media or greensand will need
to be replaced and this material also becomes a residual
product that must be disposed. Similar to the backwash
and regenerant solution from the ion exchange and acti-
vated alumina processes, the filter backwash water will
contain arsenic, the concentration dependent upon the
amount of arsenic removed and the quantity of backwash
water. Although the liquid fraction of the backwash water
will contain some soluble arsenic, most of the arsenic will
be associated with the iron/manganese solids. Depending
upon their arsenic concentration, the disposal of the back-
wash water residual and the spent solid media residual
may be subject to the disposal requirements under CWA
and RCRA.
2.5 Membrane Processes
2.5.1 Process Description
The four types of membrane processes used by small treat-
ment systems are microfiltration, ultrafiltration,
nanofiltration, and reverse osmosis, all of which are pres-
sure driven. These membranes are categorized by the larg-
est particle that can pass through them, and the molecular
weight cutoffs. Microfiltration requires the lowest pressure
and removes particles on the micron level, such as proto-
zoa. Reverse psmosis uses the highest pressure and can
remove particles at the ionic level, such as arsenic.
Nanofiltration :membranes can also remove dissolved ar-
senic (USEPA, 1998), at similar or a little lower efficiency
than reverse osmosis. Of the four types considered, only
reverse osmosis and nanofiltration can remove dissolved
arsenic because of the small size of the target contami-
nant. A simplified schematic of membrane filtration is pre-
sented in Figure 2-6 (Waypa et al., 1997).
In reverse osmosis, pressure is used to reverse the os-
motic flow of water molecules through a selectively per-
meable membrane while restricting dissolved and particu-
late matter. The removal efficiency for reverse osmosis is
typically 95 percent for arsenic (SAIC and HDR, 1994). In
these types of processes, it is important to note that the
selection of the proper membrane achieves the desired
removal efficiency. As target particle size decreases, the
selectivity of the membrane must increase. Likewise, as
membrane pore size decreases, so does the recovery rate
of treated water. If desired results for reverse osmosis and
nanofiltration are similar, nanofiltration is preferred because
it is more economical and simpler to operate (SAIC and
HDR, 1994).
2.5.2 Residual Generation and Disposal
All membrane processes produce a reject waste product
containing the materials, including arsenic, rejected by the
KMnO4 Feed
Feed
Pump
Greensand Media
Backwash/Rinse
Spent (Waste w/
Fe and Mn)
Backwash/Rinse
T
Finished Water
.I
Figure 2-5. Schematic of greensand media treatment process.
7
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Raw
Water
Pre-Treatment
Pre-Filtration
Figure 2-6. Schematic of membrane filtration process.
High
Pressure
Pump
Membrane
Filtration
Finished
Water
membrane. The reject water is generally high in total dis-
solved solids (DPRA, 1993). Depending on the concentra-
tion of the arsenic and other contaminants in the reject
water, the disposal of this waste may be subject to the
disposal requirements under CWA and RCRA.
2.6 Summary of Treatment Technologies
Each unit process described above differs in removal effi-
ciencies, residual production, and traditional residual man-
agement options. Table 2-1 presents a summary of these
five unit processes, the type of residual produced, and a
list of possible disposal methods for the residuals.
-------
Table 2-1. Summary of Residuals/Management Methods
Treatment Technology Form of Residual
Type of Residual
Possible Disposal Methods
Anion Exchange
Liquid
Solid
Regeneration Streams
-Spent Backwash
--Spent Regenerant
-Spent Rinse Stream
Sanitary Sewer
Direct Discharge
Evaporation Ponds/Lagoon
Spent Resin
Landfill
Hazardous Waste Landfill
Return to Vendor
Activated Alumina
Liquid
Solid
Regeneration Streams
-Spent Backwash
-Spent Regenerant (Caustic)
-Spent Neutralization (Acid)
-Spent Rinse
Liquid Filtrate (when brine
streams are precipitated)
Sanitary Sewer
Direct Discharge
Evaporation Ponds/Lagoon
Spent Alumina
Sludge (when brine streams
are precipitated)
Landfill
Hazardous Waste Landfill
Land Application
Media Adsorption
Liquid
Solid
Regeneration Streams
-Spent Backwash ,
-Spent Regenerant.
-Spent Rinse Stream
Spent Media
Sanitary Sewer
Direct Discharge
Evaporation Ponds/Lagoon
Landfill
Hazardous Waste Landfill
Iron and Manganese
Removal Processes
Liquid
Solid
Filter Backwash
Sludge (if separated from
backwash water)
Spent Media
Direct Discharge
Sanitary Sewer
Evaporation Ponds/Lagoons
Sanitary Sewer
Land Application
Landfill
Landfill
Hazardous Waste Landfill
Membrane Processes
Liquid
Brine (reject and backwash
streams)
Direct Discharge
Sanitary Sewer
Deep Well Injection
Evaporation Ponds/Lagoon
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3. Federal Statutory and Regulatory Requirements
Over the past few decades, federal and state environ-
mental regulations have increased in scope and stringency
such that today these regulations potentially apply to an
increasing number of drinking water contaminants once
those contaminants are removed from source waters. At
the same time, EPA is revisiting existing drinking water
quality standards and evaluating the need to establish
additional or more stringent standards. In response, wa-
ter suppliers are periodically reviewing and reevaluating
their residual management practices, and in some cases,
reevaluating unit processes used to treat their water sup-
ply.
The purpose of this section is to provide an overview of
the federal regulations that apply to the management of
residuals, with a focus on arsenic removal residuals. It is
intended to provide guidance to water suppliers on the
federal regulatory requirements of residuals management
so that they can better evaluate compliance of existing
practices, and to better plan for needed changes in their
treatment plant operations.
3.1 Key Factors in Identifying Applicable
Federal Regulations
Three factors determine which federal regulations apply
to residual management practices. These are 1) the physi-
cal form of the residual; 2) how it is managed; and 3) its
chemical make-up. The basic inquiry regarding physical
form is whether the residual is a liquid or solid (including
sludge). With regard to residual management, the key
question is what method or methods are used to manage
the residual. Finally, the chemical make-up of the residual
will determine whether the residual constitutes a hazard-
ous waste or a nonhazardous waste as defined under
RCRA. Figure 3-1 depicts how these three variables can
be used to determine which federal regulations apply to
the management of arsenic residuals. Current data on
the rate of use of each residual management method are
not available for arsenic treatment processes.1 Therefore,
the discussion below focuses on those possible disposal
methods identified in Table 2-1 (see Section 2).
The discussion below is organized with regard to the form
of the residual (liquid versus solid) and the way in which it
is managed. Issues associated with the chemical make-up
of the residual are addressed, as appropriate, within the
discussion. The management of liquid residuals is dis-
cussed first, followed by discussion of the management of
solid/sludge residuals.
3.2 Liquid Residuals
Liquid residuals from drinking water treatment plants
(DWTP) typically occur in the form of brines, caustics, filter
backwash, or reject waters generated as a residual from
the treatment process. Typically, such liquids are disposed
through either direct discharge to a waterbody, or through
indirect discharge via a sanitary sewer system; that is, a
publicly owned treatment works (POTW). Other methods
of management include underground injection, manage-
ment in lagoons, and possibly land disposal or land appli-
cation. Each of these management methods is discussed
below, including a discussion of relevant federal regula-
tions.
The CWA, 33 USC § 1251 et seq., regulates both the di-
rect and indirect discharge of pollutants. Direct discharges
of pollutants to surface waters are prohibited except in com-
pliance with a National Pollutant Discharge Elimination
System (NPDES) permit. Indirect discharges must comply
with the requirements of the federal pretreatment program.
Other generally relevant federal regulatory programs in-
clude the RCRA and SDWA.
3.2.1 Direct Discharge: CWA NPDES
A direct discharger includes any DWTP that adds any pol-
lutant via a discrete conveyance (e.g., pipe) to practically
any surface water body (including wetlands). The term
pollutant is broadly defined2 and includes chemicals used
in the treatment process.
To provide some context regarding residual management, for conventional treat-
ment systems (I.e., large drinking water systems), the most commonly used man-
agement methods for drinking water treatment residual disposal are co-disposal
(i.e., the landfilling of the residual with other wastes), land application and direct
discharge to a waterbody (Koorse, 1993). Note that these residual management
methods may not reflect the management methods used by arsenic treatment
systems since arsenic systems are typically small and may be remotely located.
2Under CWA § 502, the term pollutant includes dredged spoil, solid waste, incinera-
tor residue, sewage, garbage, sewage sludge, munitions, chemical wastes, bio-
logical materials, radioactive materials, heat, wrecked or discarded equipment, rock,
sand, cellar dirt and industrial, municipal, and agricultural waste discharged into
water.
10
-------
Form of Waste
Interim
Management
Liquid Residuals
(e.g., liquids, brines,
filtrates, etc.)
Interim Treatment
(e.g., chemical precipitation,
holding pond, evaporation
pond/lagoon)
Liquid
Solid/Sludge
Residuals
(e.g., sludges, precipitates
spent materials/media)
Sludge
Disposal
Methods
Direct
Discharge
(e.g., surface
water, wetland,
ocean)
Indirect
Discharge
(e.g., sanitary
sewer)
Underground
Injection
(e.g., deep well)
Land Disposal
(e.g., sanitary,
industrial,
hazardous landfill)
Reuse
(e.g., land
application)
Wet Land/
Ocean
Disposal
Incineration
Clean Water
Act:
NPDES Program
Clean Water
Act:
Pretreatment
Program
40 G.F.R. Parts 122-133 40 C.F.R. Parts 403
Safe Drinking
Water Act.
Underground
Injection Control
Program
Resource
Conservation
Recovery
Act:
Subtitle C&D
Programs
Resource
[Conservation
Recovery
i Act:
.Subtitle C&D
' Programs
Clean Water
Act:
Dredge and Fill
Program
Clean Air Act/
Resource
Conservation
Recovery Act
Regulatory
Programs
40 C.F.R. Parts 141-149 40 C.F.R. Parts 257-270 40 C.F.R. Parts 257-266 40 C.F.R. Parts 230-233 40 C.F.R. Parts 50, 60-63, 26
Figure 3-1. Federal regulations governing the disposal of residuals.
A DWTP that is a direct discharger must hold a NPDES
permit and may only discharge pollutants in conformance
with the terms of that permit (i.e., the DWTP is responsible
for treatment of its wastewater to the levels described in
its permit prior to discharge). For example, a preliminary
scan of EPA's Permit Compliance System (PCS) database
indicates that 2,101 facilities in Standard Industrial Classi-
fication (SIC) 49413 hold NPDES permits, and that at least
25 facilities have some permit limit or condition address-
ing arsenic.
Generally, each NPDES permit must include technology-
based effluent limits if such limits have been developed
for the industry, and water quality-based effluent limits if
application of the technology-based limits is insufficient to
achieve compliance with the water quality standards that
apply to the receiving water (water-quality based effluent
limits are discussed in greater detail in Section 4). To date,
EPA has not developed technology-based effluent limits
for water treatment plants. Therefore, such permit limits
are generally based on best professional judgement (BPJ).
"Water Supply. Establishments primarily engaged in distributing water for domes-
tic, commercial, and industrial use.
Where BPJ-based limits are used to address arsenic, ad-
ditional water quality-based effluent limits may be neces-
sary if the BPJ-based limits are not sufficient to ensure
compliance with applicable water quality standards. Un-
der CWA § 1317 and 40 CFR § 401.15, arsenic is specifi-
cally identified as a toxic pollutant. Thus, if arsenic occurs
in the effluent at levels of concern a BPJ-based effluent
limit must be developed and incorporated as a condition in
the facility's NPDES permit.
It is immaterial whether the liquid waste stream would con-
stitute a hazardous waste under RCRA if the waste is dis-,
charged in compliance with a valid NPDES permit. This is
because under RCRA (40 CFR § 261.4(a)), industrial
wastewater discharges that are point source discharges
subject to regulation under § 1342 of the CWA are ex-
cluded from the RCRA definition of solid waste (and hence,
are also excluded from the definition of hazardous waste).
Therefore, even if the residuals contain hazardous levels
of arsenic, if the facility has a NPDES permit, the disposal
of such residuals will occur pursuant to the requirements
of the CWA.
Finally, any direct discharge to the territorial seas, con-
tiguous zone, or ocean is subject to additional restrictions.
11
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Generally, no such discharges may be allowed pursuant
to a NPDES permit unless the permittee complies with
special criteria. The discharge must be deemed to be in
the public interest and cannot cause unreasonable degra-
dation of the marine environment (see 33 USC § 1343
and 40 CFR § 125.123).
3.2.2 Indirect Discharge: CWA
Pretreatment
Liquid residuals4 generated by DWTPs may also be dis-
charged to sanitary sewer systems connected to POTWs.
Such discharges known as indirect discharges do not re-
quire a NPDES permit, but must comply with applicable
pretreatment program requirements (see 40 CFR § 403).
These requirements, which are generally implemented at
the local level of government by a sewer authority or POTW
with approval from EPA, include compliance with national
general standards, national categorical standards for ex-
isting and new sources, and local limits. National general
standards include minimum requirements which are in-
tended, among other things, to prevent the introduction
into POTWs of pollutants which will interfere or be incom-
patible with the treatment works. Categorical standards
Impose industry-specific requirements designed to protect
the integrity of the POTW's operation and ensure that it
can meet its NPDES permit conditions. To date, no cat-
egorical standards have been developed for DWTPs. Fi-
nally, local limits allow indirect discharge restrictions to be
tailored to local needs and conditions.
Where an approved pretreatment program exists, general
and categorical standards and local limits are implemented
through a control mechanism, which may be a permit, li-
cense, local ordinance, or other agreement. Currently, ap-
proximately 1,600 approved pretreatment programs are
operational in the United States. Where an approved pro-
gram does not exist, both the general and categorical stan-
dards apply to indirect dischargers directly. Hence, a DWTP
with an indirect discharge must ensure compliance with
the general pretreatment standards (40 CFR § 403) and
any applicable local limits
In the case of a DWTP that discharges a wastewater con-
taining arsenic, the sewer control authority will make the
determination as to the quantity and concentration of ar-
senic that the treatment system can tolerate (i.e., the local
limit). If it is determined that the DWTP's wastewater con-
tains levels of arsenic or other contaminants that the treat-
ment system cannot safely treat, then the sewer authority
can require that the DWTP treat its wastewater prior to
discharge to the POTW. Whether a DWTP is required to
treat its wastewater prior to discharge to a POTW is wholly
dependent on the quantity of arsenic the POTW can safely
treat and the amount of arsenic discharged by the DWTP
and other dischargers.
Local limits vary significantly and can depend upon a great
number of factors. These include, but are not limited to,
the size of the POTW, the amount of arsenic from other
sources, and the efficiency of the treatment system. More-
over, DWTPs exhibit a great deal of variance in the amount
of arsenic in their intake waters and in the effectiveness of
the treatment systems in removing the arsenic and con-
centrating it in the waste stream. Because of these fac-
tors, it is difficult to state with certainty what requirements
may be placed upon a facility discharging its residual to a
POTW. Each case must be individually evaluated taking
into account the aforementioned factors.
3.2.3 Underground Injection: SDWA UIC
Liquid treatment residuals5 may be disposed via under-
ground injection, although this practice is less common
than direct or indirect discharge. Federal regulations ad-
dressing underground injection control (UIC) have been
developed by the EPA pursuant to the SDWA. Under this
program, states may assume responsibility to implement
the UIC program provided they meet minimum federal stan-
dards.
Federal UIC regulations prohibit the subsurface discharge
of fluid through a well or hole whose depth is greater than
its width without a permit. UIC regulations may affect some
septic tanks, if they are used by a community or regional
system for the injection of residuals. Individual and single
family residential systems are exempt, as are nonresiden-
tial septic systems used only for sanitary wastes and with
the capacity to serve fewer than 20 persons per day (see
40 CFR §144.1).
UIC permits generally include standard permit conditions
as well as substantive conditions addressing areas such
as construction, operation, corrective action, monitoring
and reporting, mechanical integrity, and financial respon-
sibility. Permit-by-rule is authorized in certain instances (i.e.,
a permit is deemed to be issued if the "permittee" oper-
ates in compliance with specified regulatory conditions).
The federal UIC regulations establish five classes of injec-
tion wells. UIC wells used for liquid residuals generated by
DWTPs are likely to be Class V (other) wells.6 Underground
injection is prohibited where it would cause any under-
'Federal pretreatment regulations do not define the term "liquid." However, these
regulations prohibit the indirect discharge of "solid or viscous pollutants in amounts
which will cause obstruction to the flow in the POTW resulting in interference" (40
CFR § 403.5(b)(3)}. In addition, states or localities may further define the criteria
that a material must meet to qualify for indirect discharge (e.g., pass through 3/8-
inch mesh).
5Federal UIC regulations define the term "fluid" as "any material or substance which
flows or moves whether in a semisolid, liquid, sludge, gas, or any other form or
state" (40 CFR § 144.3).
This assumes that the substance being injected is not a hazardous waste. Injec-
tion of hazardous waste is subject to Class I well requirements.
12
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ground source of drinking water to exceed any SDWA-
mandated drinking water standard (i.e., MCL) or otherwise
affect public health.
3.2.4 Land Disposal: RCRA Subtitles C/D
Bulk liquids generated by DWTPs are generally not land
disposed through landfilling due to the regulation of such
disposal, the costs of transport and disposal, and the avail-
ability of more reasonable and environmentally benign
management alternatives. This is true for both nonhazard-
ous and hazardous liquid wastes. For example, under 40
CFR § 258.28, municipal solid waste landfills (MSWLFs)
generally may not accept bulk or noncontainerized liquid
wastes. Similarly, nonhazardous industrial landfills are of-
ten subject to similar state restrictions. Liquid residuals that
constitute a hazardous waste are generally subject to com-
prehensive generator, transport, storage, treatment and
land disposal restriction requirements.
Liquids generated by DWTPs that are reused through land
application (e.g., being sprayed on crops or other land)
are subject to very limited federal regulation provided that
the liquid is not a RCRA hazardous waste (such wastes
are generally subject to comprehensive regulation). The
criteria in 40 CFR Part 257 establish basic provisions that
define those practices that constitute open dumping, which
is prohibited under § 4005 of RCRA. These provisions,
which are predominantly implemented and enforced by the
states, include requirements addressing location in a flood-
plain; protection of endangered species; protection of sur-
face water (e.g., waste management practices shall not
cause a point source discharge in violation of CWA § 402,
or a nonpoint source discharge in violation of applicable
legal requirements) and ground water (e.g., waste man-
agement practices shall not contaminate an underground
drinking water source); land application to food chain crops
(e.g., cadmium and PCB restrictions); minimizing disease
vectors; protection of air quality; and limits on explosive
gases. Thus, reuse through land application should be
consistent with these requirements and corresponding state
provisions.
The regulations applicable to the management of liquid
residuals in lagoons (i.e., surface impoundments and
evaporation ponds) are discussed in Section 3.3.4, La-
goons.
3.3 Solid/Sludge Residuals
Solid residuals from DWTPs typically occur in the form of
sludges (or precipitates) generated as residuals from the
treatment process. They may also include spent resins and
filter media that can no longer be used as part of the treat-
ment process. Typically, sludges are disposed through ei-
ther landfilling, in municipal or industrial landfills, or through
land application. Interim management may also include
storage in lagoons. Spent resins and filter media when not
disposed, may be sent back to the vendor for reactivation,
recovery, or disposal. Although no specific studies were
identified that examine whether arsenic treatment residu-
als typically constitute a hazardous waste (i.e., exhibit the
hazardous characteristic of toxicity), none of the literature
reviewed suggests that significant quantities of arsenic (or
other drinking water) treatment residuals typically consti-
tute hazardous waste. Rather, it appears that currently fed-
eral regulation of solid and sludge arsenic treatment re-
siduals occurs predominantly under RCRA Subtitle D (non-
hazardous waste). Nevertheless, since arsenic treatment
residuals can constitute a hazardous waste they must be
evaluated on a case-by-case basis and, where they do
exhibit a hazardous characteristic, the residual must be
managed pursuant to the requirements of RCRA Subtitle
C (hazardous waste).
3.3.1 Solid Waste Landfill: RCRA
Subtitle D
Depending upon the type of treatment technology em-
ployed, a DWTP may generate a solid residual in the form
of a sludge. Once a facility has determined that its solid
residual is not a hazardous waste per 40 CFR § 261.24
(toxicity characteristic) (see also 40 CFR § 262.11 (c)(2)),
then the residual may be disposed in a municipal or indus-
trial landfill. Municipal landfills must meet minimum require-
ments established under 40 CFR Part 258. Under Part 258,
MSWLFs must comply with requirements addressing lo-
cation, operation, design, ground water monitoring, cor-
rective action, closure and post-closure care, and finan-
cial assurance. The ground water monitoring requirements
include mandatory detection monitoring for arsenic (among
other constituents) followed by assessment monitoring
where a statistically significant increase over background
is identified. It is noteworthy that although the requirements
imposed under Part 258 have been developed at the fed-
eral level, these provisions are implemented under state
and local solid waste programs (i.e., the Part 258 provi-
sions are only imposed to the extent required by state laws
and regulations).
Industrial landfills, which may include monofills (landfills
designed and dedicated to the disposal of a single type of
waste), are typically regulated under state and local laws.
Such laws generally impose requirements addressing lo-
cation, design, operation, permeability (i.e., requirements
for the use of liners), run-on/runoff controls, and cover.
Many industrial landfills and monofills are located on-site
of the residual generator.
Finally, it is important to keep in mind that under no cir-
cumstances may sludges be disposed of in navigable wa-
ters (streams, rivers, lakes, or oceans) and care must be
taken that sludges do not enter navigable waters as a con-
sequence of transfer operations. Also, DWTPs are con-
sidered to be industrial facilities for purposes of the Phase
I storm water regulations (40 CFR § 122.26) and if a plant
13
-------
elects to store or dispose of sludge on-site that facility may
have to comply with CWA storm water regulations.
3.3.2 Hazardous Waste Landfill: RCRA
Subtitle C
Sludges generated from DWTPs may, in some instances,
constitute a hazardous waste7 if they exhibit the hazard-
ous characteristic of toxicity.8 For arsenic, a solid waste
constitutes a hazardous waste if the extract from a repre-
sentative sample of the solid waste (using a TCLP Test
Method 1311, as described in EPA publication SW-846)
contains equal to or greater than 5.0 mg/L. Note that other
constituents may also render a solid waste a hazardous
waste (see 40 CFR § 261.24). Any person who generates
a solid waste (i.e., DWTPs that generate a liquid, solid, or
sludge waste) must determine whether that residual con-
stitutes a hazardous waste. For DWTPs, this encompasses
either testing a sample of the residual as described above,
or making a judgement (i.e., "applying knowledge"), based
on the materials and processes used to generate the re-
sidual, as to whether it exhibits the characteristic of toxic-
ity (see 40 CFR § 262.11; § 261.10(a)(2)(ii)). Most DWTP
sludges do not exhibit the characteristic of toxicity and,
thus, are not hazardous wastes (USEPA, 1996).
If a residual is a hazardous waste, it must be managed in
compliance with the following requirements:
Hazardous Waste Generator- Hazardous waste gen-
erators must obtain an EPA identification number, as
well as comply with packaging, marking, manifesting,
accumulation and storage, record keeping and report-
ing, and land disposal restriction (LDR) requirements.
Note that the technical standards applicable to the
management of hazardous waste vary depending on
how much waste is generated per month. A DWTP
that generates residuals that must be managed as
hazardous waste may be subject to the hazardous
waste generator requirements.
Hazardous Waste Transporter - Hazardous waste
transporters must obtain an EPA identification num-
ber, as well as comply with manifest and spill clean-
up/reporting requirements.
'A hazardous waste is defined under RCRA as a solid waste or combination of solid
wastes which because of its quantity, concentration, or physical, chemical, or in-
fectious characteristics may 1) cause, or significantly contribute to an increase in
mortality or an increase in serious irreversible, or incapacitating reversible, illness;
or 2) pose a substantial present or potential hazard to human health or the envi-
ronment when improperly treated, stored, transported, or disposed of, or other-
wise managed (42 USC § 6903(5), RCRA 1004(5)). EPA has more specifically
defined hazardous wastes pursuant to regulation at 40 CFR § 261, Subparts C
and D, Note that under RCRA, liquids can meet the definition of solid wastes and
sludges from DWTP are specifically identified as solid wastes (see, 42 USC §
6903(27)}.
A solid waste may be a hazardous waste if it is specifically listed in 40 CFR §§
261.31 - 261.33 (Subpart D), or if it exhibits a hazardous characteristic, as identi-
fied In 40 CFR §§ 261.21 -24 (Subpart C). Such characteristics include ignitability,
corrosivity, reactivity, and toxicity. Wastes generated by DWTPs are not listed in
Subpart D.
Hazardous Waste Treatment, Storage, Disposal Fa-
cilities (TSDFs) - Hazardous waste TSDFs must ob-
tain an EPA identification number, as well as comply
with general facility standards, preparedness and pre-
vention, permitting, contingency plans and emergency
procedures, manifest, record keeping and reporting,
release, closure and post-closure, financial, corrective
action, land disposal restriction, and management unit
specific (e.g., surface impoundments, waste piles, and
landfills) requirements. A DWTP could be subject to
TSDF requirements if it decides to accumulate haz-
ardous waste for greater than 90 days or to treat or
dispose of its hazardous waste on-site.
To manage the universe of hazardous waste generators,
EPA has classified hazardous waste generators on the
basis of the quantity of waste produced. These classes
are as follows: 1) Large Quantity Generators (LOG) are
those facilities that produce over 1,000 kilograms per month
of hazardous waste (weight is determined based on the
condition of the waste as disposed); 2) Small Quantity Gen-
erators (SQG) are those facilities that produce greater than
100 kilograms per month of hazardous waste but less than
1,000 kilograms per month, and accumulate less than 6,000
kilograms at any one time; and 3) Conditionally Exempt
Small Quantity Generators (CESQG) are those facilities
that generate less than 100 kilograms per month of haz-
ardous waste. There are also restrictions on the amount
of waste a CESQG may accumulate. LQGs are subject to
full regulation. SQGs are subject to reduced regulation.
CESQGs are generally exempt from Subtitle C regulation
provided they appropriately manage their waste in permit-
ted or licensed state municipal or industrial landfills.
Any hazardous waste that will be disposed or placed on
the land must comply with the land disposal restriction
(LDR) regulations. Land disposal includes disposal or
placement in landfills, land treatment, surface impound-
ments, waste piles, or injection wells (40 CFR Part
268.2(c)). These regulations establish treatment standards
for each hazardous waste. The waste must meet the stan-
dard prior to land disposal. Compliance with the LDR re-
quirements may force DWTPs to treat their waste prior to
land disposal.
Finally, any DWTP that generates a hazardous waste must
be careful regarding whether that waste is mixed with other
solid wastes. Under 40 CFR § 261.3, a mixture of a char-
acteristic hazardous waste and a solid waste is a hazard-
ous waste unless the resultant mixture does not exhibit
any characteristic of hazardous waste. Facilities may not
mix characteristic hazardous waste with other wastes to
dilute the characteristic unless it is a necessary step in the
treatment process.
3.3.3 Lagoons: SD WA
Some DWTPs may choose to manage some dilute slud-
ges in lagoons to allow concentration of the sludge and
14
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provide for short-term storage. Generally, this form of man-
agement is contingent on the availability of on-site land
and the size of the treatment plant (Koorse, 1993). Where
the residuals are not a hazardous waste, on-site sludge
lagoons are regulated minimally at the federal level under
SDWA and RCRA. The SDWA requires that states estab-
lish programs to protect "wellhead" areas (i.e., areas sur-
rounding a water well or wellfield supplying a public water
system) from contaminants that may pose adverse effects
on human health. In addition, under RCRA, EPA has es-
tablished criteria that prohibit practices that contaminate
surface water or ground water (see 40 CFR § 257.3-4).
Beyond these federal requirements, contamination of
ground water is generally regulated at the state level. If
such residuals do constitute a hazardous waste, RCRA
regulations establish comprehensive design and opera-
tion standards applicable to surface impoundments (40
CFR Part 264, Subpart K).
3.3.4 Reuse of Hazardous Waste: RCRA
Subtitle C
DWTP sludges that do constitute a hazardous waste may
be reused through land application if they meet the RCRA
exemption for recyclable materials applied to the land (see
40 CFR § 266.20(b)). Under this exemption, a product that
contains hazardous materials must have undergone a
chemical reaction such that the hazardous material is ren-
dered physically inseparable, and the product must meet
the applicable RCRA LDR standards. EPA has also devel-
oped an exemption for commercial fertilizers produced from
recyclable hazardous materials provided the fertilizer meets
all applicable LDR standards.
3.3.5 Reuse of Solid Waste: RCRA
Subtitle D
Nonhazardous sludges from DWTPs may be reclaimed or
reused, typically through some form of application to the
land (this may involve mixing, or co-use, with other mate-
rials including other sludges). Where the DWTP sludge is
not a hazardous waste, there are very few federal regula-
tions that apply to such reuse. The criteria in 40 CFR Part
257 establish some provisions that define those practices
that constitute open dumping, which is prohibited under §
4005 of RCRA. As discussed above, these provisions,
which are predominantly implemented by the states, in-
clude requirements addressing location in a floodplain;
protection of endangered species; protection of surface
water and ground water; land application to food chain
crops; minimizing disease vectors; protection of air qual-
ity; and limits on explosive gases. Thus, reuse should be
consistent with these requirements. It is also worth noting
that DWTP sludges are not regulated under the sewage
sludge management regulations imposed under the CWA,
as 40 CFR § 503.6(i)(e) specifically excludes drinking wa-
ter treatment sludges from this regulatory scheme. How-
ever, state and local laws generally address such waste
management.,
3.3.6 Off-Site Disposal
DWTPs that transport treatment residuals off-site are sub-
ject to federal regulation if the residuals are a hazardous
waste, pursuant to RCRA, or if they constitute a hazard-
ous material, pursuant to the Hazardous Materials Trans-
portation Act (HMTA).
If the residual is a hazardous waste (i.e., exhibits the char-
acteristic of toxicity), it may only be transported if accom-
panied by a hazardous waste manifest. In addition, off-
site disposal of such material is subject to packaging, la-
beling, marking, placarding, record keeping, and reporting
requirements (see 40 CFR Parts 262 and 263). If the re-
sidual is a hazardous material, it is subject to regulation
developed under HMTA addressing material classification,
packaging, marking, labeling, and transport.
15
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4. Select State Regulatory Requirements
In addition to reviewing federal regulations that potentially
affect the management of arsenic drinking water treatment
residuals, this document also examines similar regulations
imposed by the following seven states: Arizona, Califor-
nia, Maine, Nebraska, New Mexico, Nevada, and Penn-
sylvania. The review of select state regulations parallels
the examination of federal regulations, focusing on char-
acterizing the requirements that may apply to the different
management options available for liquid and solid residu-
als generated by treatment systems that remove arsenic
from drinking water. The seven states selected were cho-
sen primarily based on arsenic occurrence and, second-
arily, to obtain some degree of regional representation.
Given the structure of the relevant federal environmental
programs which typically delegate program implementa-
tion authority to states that adopt consistent programs, it
is not surprising that many components of these seven
state regulatory programs are generally consistent with the
federal minimum requirements described in Section 3. This
is true with regard to the approach to surface water regu-
lation; controlling indirect discharges to sanitary sewer sys-
tems (i.e., POTWs); underground injection control; and the
approach to hazardous waste regulation, including the ar-
senic threshold under the toxicity characteristic, which de-
termines when a waste constitutes a hazardous waste
based on its arsenic content.
Nevertheless, state programs differ from federal program
requirements and each other in several important aspects.
These differences include the actual surface water quality
standards applicable to control the amount of arsenic in
direct discharges of liquid effluent, the local limits that
specify how much arsenic may be discharged to a sank
tary sewer system, the regulation of solid waste landfills,
the protection of ground water resources, and the regula-
tion of land application activities. The discussion below
summarizes important aspects of the state regulations re-
viewed. Additional discussion is provided in the individual
state subsections that follow.
4.1 Liquid Residuals
4.1.1 Direct Discharge to Surface Waters
As discussed in Section 3.2.1, EPA has not promulgated
national technology-based effluent limitation guidelines for
drinking water treatment facilities. As a result, technology-
based NPDES permit limits are based on best professional
judgement (BPJ) and, where BPJ may not be sufficient to
ensure compliance with state water quality standards, on
water quality-based effluent limits. Such water quality-based
effluent limits are calculated to ensure compliance with state
water quality standards. Thus, for purposes of assessing
state regulations that may impact direct discharges to sur-
face waters, the most relevant state standards are state
water quality standards.
State water quality standards generally include surface
water use classifications, numeric and/or narrative water
quality criteria, and an antidegradation policy. The use clas-
sification identifies surface water uses that should be pro-
tected (e.g., public water supply, recreation, and propaga-
tion of fish and wildlife),9 the numeric and narrative stan-
dards identify the level of water quality deemed sufficient
to support such uses, and the antidegradation policy pre-
vents degradation to water quality.10 The summary infor-
mation presented in this section focuses on the relevant
state numeric and narrative water quality criteria (herein-
after, the state numeric and narrative water quality criteria
are generally referred to as state water quality standards).
Table 4-1 presents a summary of the state numeric sur-
face water quality standards for arsenic. It also presents
the recommended national numeric water quality criteria
for arsenic developed by EPA. These national criteria pro-
vide guidance for states and tribes as they adopt water
quality standards pursuant to § 303(c) of the CWA. Gener-
ally, states must develop numeric surface water quality stan-
dards for arsenic (or other priority pollutants) where a dis-
charge or the presence of the pollutant could reasonably
be expected to interfere with the designated uses of a
waterbody. As a result, not all states have established nu-
meric water quality standards for arsenic for all uses or all
waterbodies.
Among the state surface water quality standards, two points
are noteworthy. First, the standards imposed for public/do-
mestic water supplies generally reflect the current drinking
'States may expand these classifications or add to them.
'"For purposes of this document, antidegradation provisions are not highly relevant
and, therefore, are not discussed.
16
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Table 4-1. Summary of Federal Recommended and Select State Surface Water Quality Standards for Arsenic
Domestic Fish
State Water Consumption
Recommended
Federal Criteria
for Arsenic
Arizona
California1
Maine2
Nebraska
New Mexico
Nevada
Pennsylvania
Full Body Partial Body
Contact Contact Livestock Irrigation
Freshwater: Acute - 0.34 mg/L; Chronic - 0.15 mg/L
Saltwater: Acute - 0.069 mg/L; Chronic - 0.036 mg/L
0.05 mg/L
1 .45 mg/L
0.05 mg/L
0.05 mg/L
0.2 mg/L
2.0 mg/L
Freshwater: Acute - 0.34 mg/L; Chronic - 0.1 5 mg/L
Saltwater: Acute - 0.069 mg/L; Chronic - 0.036 mg/L
Freshwater: Acute - 0.34 mg/L; Chronic -
Saltwater: Acute - 0.069 mg/L; Chronic -
0.05 mg/L
0.05 mg/L
0.05 mg/L
Varies
NA
NA
0.1 5 mg/L
0.036 mg/L
NA
NA
NA
Freshwater: Acute - 0.36 mg/L; Chronic -
; NA
' NA
NA
NA
0.2 mg/L
0.2 mg/L
NA
0.1 mg/L
0.1 mg/L
0.1 9 mg/L
1 Standards proposed under California Toxics Rule (62 Federal Register42160; August 5,1997).
2 Adopts federal water quality criteria.
water MCL. This is likely a result of the states adopting the
MCL in lieu of independently developing a risk-based stan-
dard and the fact that some state laws specifically prohibit
degradation of drinking water sources beyond current drink-
ing water standards. It also suggests that a change in the
MCL may result in a change in water quality standards of
these states. Second, three states adopted the federal cri-
teria; however, California is expected to revert back to its
somewhat unique regional implementation of water qual-
ity standards in time.
Three of the states reviewed, Arizona, Maine, and New
Mexico, are not currently authorized to implement the
NPDES program. In these states, the appropriate EPA re-
gional office is responsible for issuing NPDES permits for
any direct discharge of pollutants from a point source to a
surface water. The respective states must certify that the
EPA-issued permit complies with applicable state water
quality standards. In states not authorized to issue NPDES
permits, the state may also impose state permit require-
ments that apply in addition to any NPDES permit. For
example, Maine requires that direct dischargers obtain both
an NPDES and a state permit, with the state permit based
on both assimilative capacity and designated uses of the
waterbody.
4.1.2 Indirect Discharges to a Sanitary
Sewer System
Where a DWTP may discharge effluent to a sanitary sewer
system, the key regulatory standard is the local limit im-
posed by the local pretreatment authority. Such local lim-
its determine the amount of arsenic that may be indirectly
discharged to the POTW. Examples of such limits from
the seven states reviewed are presented in Table 4-2. As
discussed in Section 3, local limits are implemented through
the relevant control mechanism (e.g., permit, license, lo-
cal ordinance, or agreement).
In addition to any relevant local limit, DWTPs must also
understand the potential for indirect discharges to affect
the quality of sewage sludge generated by a POTW, be-
cause reuse and disposal of sewage sludge is regulated,
including being subject to numeric standards for arsenic,
under 40 CFR Part 503.11 If the indirect discharge of a liq-
uid residual to a sanitary sewer system causes the sew-
age sludge generated by the receiving POTW to exceed
the applicable sewage sludge standard for arsenic, the
control authority is likely to impose restrictions on the indi-
rect discharge of arsenic to the POTW. Two of the states
examined explicitly address this in their regulations. Ne-
braska provides that pretreatment permits must ensure
compliance with sewage sludge requirements. Similarly,
Pennsylvania provides that local limits must ensure com-
pliance with the POTW's NPDES permit and sludge use
"Under 40 CFR Part 503, no land application of sewage sludge may cause the
arsenic level to exceed 75 mg/kg. In addition, where sewage sludge is applied in
bulk, cumulative arsenic loading may not exceed 41 kg/hectare or 41 mg/kg monthly
average (40 CFR § 503.13).
17
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Table 4-2. Examples of Arsenic Local Limits for Selected States
State LocalJurisdiction Local Arsenic Limit
Arizona
Phoenix
0.1 mg/L
California
Tijuana International
Plant
0.27 Ibs/Mgal
(based on sludge
contamination)
Maine
Nebraska
New Mexico
Nevada
Pennsylvania
NA
NA (under development)
Albuquerque
Farmington
Las Cruces
Santa Fe
NA
NA
NA
NA
0.051 mg/L
1.07 mg/L
(proposed limit of
6.60 mg/L)
0.66 mg/L
(proposed limit of
0.06 mg/L)
2.74 mg/L
NA
NA
NA- Not identified. This does not necessarily mean such limits do not exist.
or disposal practices. Nevertheless, because the Part 503
requirements apply to all the states examined, sewage
sludge contamination is a potential issue for all seven
states.
4.1.3 Underground Injection
The underground injection provisions of the states exam-
ined are generally consistent with the federal requirements
as described in Section 3. Five of the states examined are
authorized to implement the UIC program. In Arizona and
Pennsylvania, the EPA regional office implements the pro-
gram. Generally, the state UIC programs do not focus on
arsenic contamination except in the context of prohibiting
contamination of drinking water sources and protecting
ground water and surface water in general (e.g., Arizona,
Nebraska, and New Mexico have ground water standards
for arsenic). New Mexico prohibits the injection of fluids
into ground water with low total dissolved solids (TDS)
(10,000 mg/L or less TDS) unless such an aquifer is des-
ignated for the injection of contaminants, and then the state
imposes an arsenic ground water quality standard of 0.1
mg/L.
4.1.4 Land Disposal
All of the states examined except Arizona restrict or pro-
hibit the disposal of bulk or noncontainerized liquids in their
general municipal landfills. These requirements are gen-
erally a result of similar restrictions imposed under 40 CFR
Part 258, which has been adopted in at least 40 states.
The states that impose these restrictions generally pro-
vide some limited exceptions. Arizona does not explicitly
restrict the management of liquids in landfills, but does pro-
vide that landfills must be located and managed so that
seepage will not create a health hazard, nuisance, or cause
pollution of any surface or ground water in the state. Cali-
fornia is somewhat unique in that in addition to adopting
the Part 258 requirements restricting liquids disposal, Cali-
fornia also has adopted provisions that specifically address
the disposal of DWTP sludge at landfills. These provisions
specify a minimum percent solids (15 percent), solids-to-
liquid ratio (5:1), and certain design parameters (leachate
collection and removal system) for landfills that accept
DWTP sludge. No other state examined addresses DWTP
residuals at this level of detail.
4.2 Solid/Sludge Residuals
4.2.1 Solid Waste Landfills
The provisions imposed under 40 CFR Part 258 require
municipal solid waste landfills to comply with ground wa-
ter monitoring requirements (including monitoring for ar-
senic) and other design and operating provisions as de-
scribed in Section 3. These requirements are implemented
at the state level and, as noted, have been adopted by at
least 40 states. All of the states examined require some
form of comparable ground water monitoring except Ari-
zona and Nebraska. Both Arizona and Nebraska impose
basic landfill requirements and also impose ground water
quality standards for arsenic to ensure adequate environ-
mental protection. California, as discussed above, imple-
ments the Part 258 requirements on a regional basis and
has developed specific landfill requirements that apply to
DWTP residuals (i.e., 15 percent minimum solids, 5:1 sol-
ids to liquid ratio, and mandatory leachate collection and
removal system).
4.2.2 Hazardous Waste Landfills
All of the states examined define a waste that exhibits the
characteristic of toxicity as a hazardous waste. These states
all adopt the federal arsenic standard for purposes of the
toxicity characteristic (i.e., 5.0 mg/L). If the extract from a
representative sample of the waste (based on use of the
TCLP) exceeds this threshold, the waste is regulated as a
hazardous waste. California also has developed an addi-
tional leaching test known as the waste extraction test
(WET). Based on the WET, California defines as a haz-
ardous waste those wastes that have an arsenic soluble
limit threshold concentration of 5.0 mg/L, and those wastes
that have a total arsenic threshold limit concentration of
500 mg/kg.
4.2.3 Lagoons
The seven states regulate the use of lagoons (which are
defined here to include surface impoundments and evapo-
ration ponds) both directly and through the imposition of
18
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ground water (or aquifer protection) standards. Most of the
states examined impose general design and operation
standards for lagoons. Arizona goes so far as to require
aquifer protection permits that include discharge limits and
best management technologies. Some states, such as New
Mexico, rely on the imposition of ground water quality pro-
tection standards to ensure that lagoons do not pollute
ground waters. In contrast, California requires facilities to
detect, characterize, and respond to releases to surface
and ground waters, but implements these requirements
on a site-specific basis (and regional plans may be more
stringent). Finally, pursuant to federal regulations as
adopted in RCRA-authorized states, all lagoons that man-
age hazardous waste are subject to comprehensive regu-
lations (e.g., liners, leachate collection, ground water moni-
toring, etc.).
The second type of state requirement that may affect the
use of lagoons, as well as other waste management ac-
tivities, is the imposition of ground water (or aquifer pro-
tection) standards. Table 4-3 summarizes the ground wa-
ter standards identified for the states that were examined.
These states may use numeric, narrative, or classifications
to protect ground water or may address the issue on a
case-by-case basis.
4.2.4 Reuse (Land Application)
The land application of DWTP sludge appears regulated
primarily on a case-by-case basis. Under their respective
state regulations, California, Maine, and Nevada develop
and impose requirements for the land application of DWTP
sludge on a case-by-case basis. Each state requires that
an approval be obtained for land application, and each fo-
cuses on ensuring that such application is performed at
agronomic rates and in such a manner as to minimize en-
vironmental impacts. Arizona, New Mexico, and Pennsyl-
vania have adopted regulations consistent with the fed-
eral sewage sludge land application standards (40 CFR
Part 503), including the numeric limits for arsenic. In each
of these states, however, these provisions do not apply to
the land application of DWTP sludge. Rather, such land
application is likely regulated on a case-by-case basis. Note
that the federal sewage sludge standards for arsenic may
or may not be used as guidance by these states.
Nebraska's sludge land application regulations expressly
apply to DWTP sludge. The state requires that such land
application be conducted pursuant to a permit that includes
basic operating, reporting and recordkeeping requirements,
but Nebraska has not developed any numeric standard for
arsenic concentration or loading. Table 4-4 summarizes
the state regulations affecting land application.
None of the seven states examined are authorized to imple-
ment the 40 CFR Part 503 standards applicable to the land
application of sewage sludge. Therefore, the respective
EPA regional offices implement this program within these
states. Under the federal regulations, sewage sludge does
not include DWTP sludge (unless mixed).
4.2.5 Off-Site Disposal
All seven states have either adopted in regulation or
adopted by reference the federal hazardous waste trans-
portation regulations and the basic provisions imposed by
the U.S. Department of Transportation under the Hazard-
ous Materials Transportation Act (HMTA). Thus, DWTPs
that transport treatment residuals off-site are subject to
regulation if the residuals are a hazardous waste, or if they
constitute a hazardous material. Generally, the transport
of such residuals will be regulated as hazardous waste if
at all, since the hazardous material requirements focus on
acute toxicity, which is not likely to be present in drinking
water treatment residuals.
If a residual is a hazardous waste (i.e., exhibits the char-
acteristic of toxicity), it may only be transported if accom-
panied by a hazardous waste manifest. In addition, off-
site disposal of such material is subject to packaging, la-
beling, marking, placarding, recordkeeping, and reporting
requirements. If the residual is a hazardous material, it is
subject to regulations developed under HMTA addressing
material classification, packaging, marking, labeling, and
transport.
The remaining subsections provide a more in-depth dis-
cussion of each state's relevant regulations.
4.3 Arizona
4.3.1 Liquid Residuals
Direct Discharge to Surface Water
Arizona is not currently authorized to implement the N PDES
program. Nevertheless, through agreements with EPA Re-
gion 9, Arizona does administer some aspects of the
NPDES program. These include permit processing for
those entities that directly discharge pollutants to surface
waters within Arizona (including development of the requi-
site technology-based and water quality-based effluent lim-
its), preparation of permit compliance monitoring reports,
and reporting noncompliance. EPA Region 9 issues and
enforces the NPDES permits in Arizona. When EPA is-
sues the NPDES permit the State of Arizona must certify
that the permit will meet Arizona water quality standards
for surface waters before the final NPDES permit may be
issued.
Arizona has developed numeric arsenic water-quality stan-
dards applicable to surface waters.12These standards13 are
12These standards are developed by the Arizona Department of Environmental
Quality, Office of Water Quality.
"Arizona Administrative Code Title 18, Chapter 11, Article 1, Appendix A.
19
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Table 4.3. Select State Arsenic Ground Water Quality Standards
State
Ground Water/
Aquifer Protection
Standard
Comment
Arizona
California
Maine
Nebraska
New Mexico
Nevada
Pennsylvania
0.05 mg/L
Varies
Narrative ground
water classifications
0.05 mg/L
0.1 mg/L
NA
NA
Applies to aquifers classified for drinking water protected use.
State also imposes narrative aquifer water quality standards (see
state discussion).
Developed as needed and on a site-specific basis. Regional
plans may also establish such standards.
Two classifications (see state discussion).
Applies to any activity that could impact ground water. Imple-
mented either through existing regulatory programs or applied
directly. State also has narrative ground water quality standards
(see state discussion).
Applicable to ground water with 10,000 mg/LTDS or less. Dis-
charge of effluent or leachate into ground water only allowed
subject to approved plan.
Ground water protection and mining reclamation section (DbNR)
focuses on ground water protection.
Persons must prevent polluting substances from reaching
waters of the state. Impoundments must be impermeable.
presented in Table 4-5.14 These surface water quality stan-
dards vary based on the designated use of each water
body within the state (e.g., domestic consumption, fish con-
sumption, contact recreation, agriculture, etc.).15 Each sur-
face water that is assigned each of the designated uses
described in Table 4-5 should meet the corresponding ar-
senic limit specified. To ensure this occurs, each NPDES
permit issued to each direct discharger in the state must
ensure that the effluent discharged by that facility does
not cause a violation of the corresponding arsenic stan-
dard at the point of discharge or in a mixing zone in rea-
sonable proximity to the discharge. Typically, facilities
employ effluent treatment to achieve compliance with
NPDES permit limits.
Arizona also provides that certain surface waters may be
designated as unique waters where the waterbody is of
exceptional recreational or ecological value. Only one sur-
face water, Peeples Canyon Creek, a tributary to the Santa
Maria River, is currently classified as a unique water with
"Note: These state water quality standards do not apply to waste treatment sys-
tems (including impoundments, ponds, lagoons that are part of such systems)
(R18-1M02).
"Designated uses for the state's water bodies are listed in Title 18, Chapter 11,
Article 1, Appendix B.
an arsenic limit (0.020 mg/L) (R18-11-112). This limit pre-
empts the numeric standards listed above for this
waterbody.
In addition to the numeric surface water quality standards,
Arizona also imposes narrative surface water quality stan-
dards that provide that such waters must be free from pol-
lutants in amounts that:
Are toxic to humans, animals, plants, or other organ-
isms
Cause or contribute to a violation of an aquifer water
quality standard (R18-11-405/406).16
Any discharge of an arsenic residual that is deemed to
violate these standards would be prohibited or limited
through NPDES permit conditions.
Indirect Discharge to a Sanitary Sewer System
Arizona does not establish state limits for indirect dis-
charges (i.e., discharges to public sanitary sewer systems
and treatment works). Local limits may be established by
'"Note: Only relevant narrative standards are included here.
20
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Table 4-4. Select State Land Application Standards for DWTP Sludge
State Land Application
Comment
Arizona
California
Maine
Nebraska
New Mexico
Nevada
Pennsylvania
State biosolids land application standards are
the same as federal sewage sludge standards.
No state sludge land application program.
Upon application, State Water Resource Control
Board (SWRCB) or regional boards must
prescribe requirements.
State also has land treatment unit (LTD)
regulations.
Land application of municipal and industrial
sludge prohibited unless pursuant to state
approval.
State has both sludge and sewage sludge
regulations. Sludge regulations expressly
apply to DWTP solid, semisolid, and liquid
wastes.
State sewage sludge land application standards
are the same as federal sewage sludge
standards.
Special waste disposal subject to approved plan
and approval of solid waste management
authority.
State sewage sludge land application standards
are the same as federal sewage sludge
standards.
State biosolids standards do not apply to
DWTP sludge (unless DWTP sludge is
mixed with biosolids).
State requires land application at agro-
nomic rates, mitigation of environmental
impacts and hazards, and consultation
with other state agencies. Regional
boards may impose additional
requirements.
LTU provisions specify development of
waste discharge requirements (i.e.,
specific elements of land treatment
programs).
Requirements based on crop or soil
requirements. Cannot pollute waters of
state or violate drinking water standards.
State regulations do not specify arsenic
land application standard.
Permit required for land application of
sludge, including compliance require-
ments and duration, schedule, reporting
and recordkeeping provisions. No arsenic
standard specified.
Sewage sludge standards do not apply
to DWTP residuals.
State sewage sludge standards do not
apply to DWTP sludge (unless DWTP
sludge is mixed with sewage sludge).
Special wastes include sewage sludge
but do not mention DWTP or other
commercial or industrial sludges. DWTP
sludge probably addressed on case-by-
case basis.
No explicit requirements that apply to
DWTP sludge.
local sewer authorities or POTWs that administer pretreat-
ment programs. For example, Phoenix imposes a local limit
for arsenic of 0.1 mg/L (although this limit is being recon-
sidered). Indirect discharges remain subject to the national
general pretreatment standards (e.g., restrictions designed
to prevent the introduction into POTWs of pollutants which
will interfere with or pass through the treatment works).
Arizona does have a regulatory program that addresses
the land application of biosolids generated by POTWs (see
discussion under Solid/Sludge Residuals, Reuse). If the
indirect discharge of a liquid residual to a sewer system
causes the biosolids generated by the receiving POTW to
exceed the applicable biosolids standards for arsenic, the
POTW is likely to impose restrictions on the indirect dis-
charge of arsenic.
Underground Injection
EPA Region 9 administers the UIC program in Arizona (40
CFR § 147.151). The program consists of the requirements
specified in 40 CFR Parts 124 (Procedures for
Decisionmaking), 144 (UIC Program), 146 (UIC Criteria
and Standards), and 148 (Hazardous Waste Injection Re-
21
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Table 4-5. Arizona's Designated Use Numeric Arsenic Surface Water Quality Standards
Domestic Water
Source
Fish
Consumption
Full Body
Contact
Partial Body
Contact
Agricultural
Irrigation
Agricultural
Livestock Watering
0.05 mg/L (total)
1.45mg/L
0.050 mg/L
0.050 mg/L
2.0 mg/L
0.2 mg/L
strictions). Thus, the UIC requirements imposed in Arizona
are the same as those described previously in Section
3.2.3. Arizona also imposes aquifer water quality standards
that may affect UIC disposal. These requirements are de-
scribed below under Solid/Sludge Residuals, Lagoons.
Land Disposal
Arizona has not adopted the federal municipal solid waste
landfill criteria (40 CFR Part 258). Thus, the state does not
explicitly ban disposal of bulk liquids in landfills. However,
the state does provide that landfills must be located so
that seepage will not create a health hazard, nuisance, or
cause pollution of any watercourse or water bearing strata.
4.3.2 Solid/Sludge Residuals
Solid Waste Landfills
As discussed above, Arizona has not adopted the federal
municipal solid waste landfill criteria (40 CFR Part 258).
Rather, Arizona imposes very basic landfill requirements,
including provisions addressing location (to prevent seep-
age), surface drainage, litter control, fire control, vector
control, a prohibition on burning, access roads, proper
equipment, and cover and compaction. Solid waste land-
fills located in Arizona are not required to monitor ground
water under and around the landfill for releases of arsenic.
However, Arizona does have aquifer water quality stan-
dards that indirectly restrict the amount of arsenic that can
be discharged from a landfill (R18-8-512). The aquifer
water quality standards are discussed under Lagoons.
Arizona also has developed regulations that address spe-
cial wastes (i.e., solid wastes that are not hazardous wastes
but that require special handling and management to pro-
tect public health or the environment); however, these regu-
lations do not explicitly apply to arsenic residuals.17
Hazardous Waste Landfills
Arizona is authorized to implement the federal RCRA pro-
gram. The state incorporates the federal hazardous waste
regulations by reference with limited exceptions (R18-8-
260). Thus, Arizona imposes the same toxicity character-
istic standard as imposed under federal regulations (i.e.,
'The stale currently designates waste that contains petroleum contaminated soils,
waste from shredding motor vehicles, and certain asbestos wastes as special
wastes.
5.0 mg/L). One area where Arizona is more stringent than
the corresponding federal requirements is reporting. Ari-
zona requires annual reports of the amount and types of
hazardous waste generated, whereas, federal regulations
require biannual waste reports. In addition, Arizona may
require reports of any conditionally exempt small quantity
generator or group of conditionally exempt small quantity
generators regarding the treatment, storage, transporta-
tion, disposal, or management of hazardous waste if such
hazardous waste poses a substantial present or potential
hazard to human health or the environment when it is im-
properly managed. Arizona law also requires businesses
and state agencies to develop and implement pollution
prevention plans to minimize the generation of hazardous
waste.
Lagoons
Arizona has established a ground water protection pro-
gram that includes requirements for aquifer protection per-
mits and establishes aquifer water quality standards. Aqui-
fer protection permits are required for all persons that con-
duct activities that result in a discharge to an aquifer (e.g.,
such as the management of a liquid or sludge in an un-
lined lagoon). Individual and general permit coverage is
available, and permits generally include discharge limits
and require use of the best available control technologies
to avoid or control discharges. Permits may impose moni-
toring and reporting requirements among their various per-
mit conditions. Permit applications must demonstrate that
the activity will not cause or contribute to a violation of an
aquifer water quality standard.
Aquifer water quality standards function to protect Arizona's
aquifers from contamination. These standards include nu-
meric and narrative aquifer water quality standards. The
numeric aquifer water quality standards apply to aquifers
classified for drinking water protected use. The numeric
aquifer water quality standard for arsenic is 0.05 mg/L (R18-
11-406).
The narrative aquifer water quality standards provide:
A discharge [to ground water] shall not cause a pollut-
ant to be present in an aquifer classified for a drinking
water protected use in a concentration which endan-
gers human health.
A discharge [to ground water] shall not cause or con-
tribute to a violation of a water quality standard estab-
lished for a navigable water of the state (note: this stan-
22
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dard focuses on the contamination of ground water
that may influence surface water quality through some
form of hydrological connection).
A discharge [to ground water] shall not cause a pollut-
ant to be present in an aquifer which impairs existing
or reasonably foreseeable uses of water in an aquifer
(R18-11-405).
No arsenic treatment residuals, whether liquid, solid, or
semisolid, may be managed in a manner likely to cause a
violation of either the numeric or narrative standards de-
scribed above. Implementation is likely to involve imposi-
tion of specific design and operation requirements for new
waste management units (e.g., lagoons), and monitoring
for existing waste management units located such that they
could impact drinking water sources. Note: the land appli-
cation of biosolids in compliance with Arizona Administra-
tive Code (AAC) 13, Article 15 is exempt from the aquifer
permit program requirements.
Reuse (Land Application)
Arizona has in place a regulatory program for the land
application of biosolids. Biosolids are defined to include
sewage sludge, but exclude sludge generated during the
treatment of either surface water or ground water used for
drinking. Note: if sewage sludge is mixed with drinking
water treatment residual sludge such a mixture may be
subject to biosolids regulation.18
Under Arizona's biosolids program, persons applying bulk
biosolids (over 1 metric ton) must register with the state
and must follow specified management practices. In addi-
tion, Arizona has established site restriction, vector attrac-
tion reduction, off-site disposal, self-monitoring,
recordkeeping, reporting, and enforcement requirements
for biosolids application. Arizona also has developed the
following restrictions on the concentrations of arsenic al-
lowed in biosolids applied to the land:
Biosolids being land applied may not contain arsenic
levels that exceed 75.0 mg/kg.
The monthly average arsenic concentration for excep-
tional quality biosolids applied to the land may not ex-
ceed 41.0 mg/kg.
Annual arsenic loadings from bulk biosolids applied to
the land may not exceed 2.0 kg/hectare.
Cumulative arsenic loadings from bulk biosolids ap-
plied to the land may not exceed 41.0 kg/hectare (R18-
13-1505).
"States may also use their biosolids or sewage sludge standards as default stan-
dards for DWTP sludge land application where no other standard exists to guide
such residual management.
These standards are generally consistent with the federal
sewage sludge land application standards established un-
der 40 CFR Part 503. Arizona's biosolids program is not
currently authorized by EPA pursuant to 40 CFR Part 501.
Therefore, EPA remains responsible for permitting facili-
ties managing sewage sludge. Any state requirements
applicable to DWTP sludge would apply in addition to these
federal requirements.
4.4 California
4.4.1 Liquid Residuals
Direct Discharge to Surface Waters
California is authorized to administer the NPDES program
through its State Water Resource Control Board (SWRCB).
Under the SWRCB, there are nine Regional Water Quality
Control Boards (RWQCBs) which have the authority to
adopt regional water quality control plans, prescribe waste
discharge requirements, and perform other water quality
control functions within their respective regions. These re-
gional boards develop regional basin plans, which include
designations for surface water beneficial uses to be pro-
tected, surface water quality objectives to protect those
uses, and a program of implementation needed for achiev-
ing the objectives for all surface waters covered by the
plans. These beneficial uses and their corresponding wa-
ter quality objectives, combined with water quality criteria
imposed under three statewide surface water quality plans,
normally serve as California's water quality standards. In
addition, regional basin plans can adopt specific water qual-
ity standards. However, due to litigation in California State
court, most of the surface water quality standards imposed
under the statewide plans have been struck down, and
will be preempted by the proposed California Toxics Rule
(CTR). This rule, when final, will establish water quality
standards for much of California.
Table 4-6 presents the proposed numeric surface water
quality standards under the CTR. Table 4-7 presents the
numeric surface water quality standards that are imposed
under the regional basin plans. Once the CTR requirements
are final, they will establish the minimum standards until
the state reissues its statewide surface water plans (i.e.,
regional basin plan requirements could be more stringent
but not less). '
Under the proposed CTR, no human health criteria were
established. Rather, EPA suggested that state permitting
authorities rely on existing narrative water quality criteria
to establish effluent limits as necessary for arsenic.
These regional basin plans also include narrative water
quality standards (described as narrative objectives). An
example of a narrative standard, found in the Colorado
River Basin Plan, is the following provision:
No individual chemical or combination of chemicals
shall be present in concentrations that adversely af-
23
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Table 4-6. California Toxics Rule Proposed Surface Water Quality Standards19
Contaminant
Arsenic
Freshwater - Acute
0.34 mg/L
Freshwater - Chronic
0.1 5 mg/L
Saltwater - Acute
0.069 mg/L
Saltwater - Chronic
0.036 mg/L
Table 4-7. Arsenic Surface Water Quality Standards in California Regional Basin Plans
Rule or Regional
Basin Plans Domestic or Municipal Supply
Central Coast
Colorado River Basin
Central Valley
Los Angeles
Lahontan
North Coast (Water
0.05 mg/L
0.05 mg/L
0.01 mg/L2
0.05 mg/L3
0.05 mg/L4
0.01 mg/L
I rrigation/Livestock
0.1 mg/L
0.2 mg/L
NA
NA
NA
NA
NA
Marine
0.008 mg/L - 6-month median
0.032 mg/L - daily maximum
0.080 mg/L - instantaneous maximum1
NA
NA
NA
NA
0.008 mg/L - 6-month median
Quality Control Plan)
Santa Ana River Basin 0.05 mg/L
San Diego 0.05 mg/L
San Francisco NA
NA
NA
NA
0.032 mg/L - daily maximum
0.080 mg/L - instantaneous maximum
NA
NA
NA
'These standards are the same as those included in the SWRCB California Ocean Plan (1990).
zApplicabte inland surface waters: Sacramento River from Keswick Dam to the I Street Bridge at City of Sacramento; American River from Folsom Dam to the Sacra-
mento River; Folsom Lake; and the Sacramento-San Joaquin Delta.
'Numerous waters are listed on state's CWA § 303(d) list as impaired for arsenic, but their priority low.
Bryant Creek Basin.
feet beneficial uses. There shall be no increase in haz-
ardous chemical concentrations found in bottom sedi-
ments or aquatic life.
Any discharge of an arsenic residual that is deemed to
violate any applicable narrative surface water quality stan-
dard would be prohibited or limited through NPDES permit
conditions.
California also imposes general requirements that provide
that surface and ground water must be protected from silt-
ation and pollutants which may diminish water quality as
required by the federal CWA, the California Porter-Cologne
"Acuta limits may not be exceeded for 1 hour in any 3-year period. Chronic limits
may not be exceeded for any 96-hour (4-day) period in any 3-year period.
Act, county anti-siltation ordinances, the RWQCB or the
SWRCB.
Indirect Discharges to a Sanitary Sewer System
California does not establish state limits for indirect dis-
charges (i.e., discharges to public sanitary sewer systems
and treatment works), but does establish general pretreat-
ment requirements in its regional basin plans. These pro-
visions describe when pretreatment requirements are ap-
plicable, the objectives of the pretreatment program (e.g.,
preventing the introduction into POTWs of pollutants which
will interfere with or pass through the treatment works),
the basic elements of a pretreatment program, and may
identify which municipalities are required to develop and
implement a pretreatment program. Local limits that ad-
dress arsenic may be established by local sewer authori-
ties or POTWs that administer pretreatment programs
24
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where such limits are needed to achieve program objec-
tives. For example, San Diego had a local limit for arsenic,
but was allowed to delete this local limit based on a deter-
mination that there was no need to retain it. The Tijuana
International Plant has a maximum allowable headworks
loading (MAHL) of 0.27 Ibs/Mgal based on sludge con-
tamination.
Underground Injection
California administers their federal DIG program, except
on Indian Lands (40 CFR § 147.250). Program require-
ments include filing, notification, operating, and testing re-
quirements for underground injection projects, similar to
federal requirements. Approval must be obtained from the
state before any subsurface injection or disposal project
can begin.
Land Disposal
California has adopted the federal municipal solid waste
landfill criteria (40 CFR Part 258) and provides that the
regional control boards must implement these require-
ments. Thus, California prohibits the disposal of bulk liq-
uids in solid waste (i.e., Class III) landfills. At Class II land-
fills (designated wastes), California also provides that
wastes that contain liquids in excess of the moisture hold-
ing capacity of the waste in the landfill must be managed
in a surface impoundment or an equally protective waste
management unit. California also has developed specific
requirements applicable to the management of sewage
sludge or water treatment sludge in Class III landfills. These
provisions are discussed below under Solid/Sludge Re-
siduals, Solid Waste Landfills.
4.4.2 Solid/Sludge Residuals
Solid Waste Landfills
Municipal solid waste is generally managed in Class III
landfills. As noted above, California has adopted the fed-
eral municipal solid waste landfill criteria (40 CFR Part 258)
and provides that the regional control boards must imple-
ment these requirements (the 40 CFR Part 258 criteria
are also deemed to supplement state requirements). These
regional boards regulate all the active waste management
units. Waste management units must be sited in an area
where the depth to ground water is very great or where
natural geologic features will provide containment. A Class
III waste management unit must also have a clay or syn-
thetic liner with a leachate collection and removal system,
if there is a possibility that ground water could be impacted
by leakage from the unit. Ground water monitoring is re-
quired for solid waste landfills, including monitoring for ar-
senic. Where detection monitoring reveals an increase in
arsenic levels, evaluation and corrective action monitor-
ing may be required.
California State regulations explicitly provide that water
treatment sludge (i.e., DWTP sludge) may be discharged
at a Class III landfill under the following conditions, unless
the state (determines that the waste must be managed as
hazardous waste:
The Icindfillis equipped with a leachate collection and
removal system.
The sludge: contains at least 15 percent solids.
A minimum solids-to-liquid ratio of 5:1 by weight shall
be maintained to ensure that the co-disposal will not
exceed the initial moisture-holding capacity of the non-
hazardous solid waste. The actual ratio required by
the regional water quality control boards is to be based
on site-specific conditions.
Hazardous Waste Landfills
California is authorized to implement the federal RCRA
program and provides that hazardous waste must be dis-
posed in Class I landfills. California incorporates the fed-
eral hazardous waste regulations in conjunction with some
of its own regulatory requirements. California imposes the
same toxicity characteristic standard as imposed under
federal regulations (i.e., 5.0 mg/L) (based on the TCLP
extraction test, which is the extraction test specified under
federal regulations). In addition, California has developed
its own waste extraction test (WET). Based on the WET
test, California also defines as hazardous waste those
wastes that have an arsenic soluble limit threshold con-
centration of 5.0 mg/L, and those wastes that have a total
arsenic threshold limit concentration of 500 mg/kg. Finally,
California has identified certain specific hazardous wastes
which the state subjects to land disposal restrictions,As of
January 1, 1984, liquid hazardous wastes, including free
liquids associated with any solid or sludge, containing ar-
senic and/or arsenic compounds (as As) in concentrations
greater than or equal to 500 mg/L are prohibited from land
disposal, even in hazardous waste land disposal units.
Lagoons
California regulations provide that owners or operators of
facilities that treat, store, or dispose of waste in a surface
impoundment, waste pile, landfill, or land treatment unit
must comply with state regulations for detecting, charac-
terizing, and responding to releases of pollutants to ground
water, surface water, or the unsaturated zone. For surface
impoundments, these requirements are implemented
through the development of a site-specific list of constitu-
ents of concern, relevant standards for those constituents,
and a plan for monitoring for any exceedance of those stan-
dards. Regional basin plans may impose more specific
requirements with regard to protecting ground water qual-
ity (e.g., the Lahontan Regional Basin Plan imposes spe-
cific ground water protection and management provisions).
California also has regulations that require that Class II
25
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surface impoundments must have a liner system designed
in accordance with state regulations.
Reuse (Land Application)
California has not developed a state sludge program, but
provides that the SWRCB or a regional board, upon re-
ceipt of applications for waste discharge requirements for
discharges of dewatered, treated, or chemically fixed sew-
age sludge and other biological solids, must prescribe gen-
eral waste discharge requirements for that sludge and those
other solids. The general waste discharge requirements
must include minimum standards for agronomic applica-
tions of sewage sludge and other biological solids and the
use of that sludge and those other solids as a soil amend-
ment or fertilizer in agriculture, forestry, and surface min-
ing reclamation. The requirements must include provisions
to mitigate significant environmental impacts, potential soil
erosion, odors, the degradation of surface water quality or
fish or wildlife habitat, the accidental release of hazardous
substances, and any potential hazard to the public health
or safety. In developing these requirements, the relevant
board must consult with the State Air Resources Board,
the Department of Food and Agriculture, and the Califor-
nia Integrated Waste Management Board. California is not
authorized to implement the NPDES Part 503 sludge pro-
gram. Thus, EPA Region 9 implements these requirements
in California.
California also has regulations that address the manage-
ment of waste in land treatment units (LTUs).20 Discharg-
ers who treat or dispose of wastes in LTUs must demon-
strate, prior to application of the waste, that waste can be
completely degraded, transformed, or immobilized in the
treatment zone (through use of a test plot followed by sam-
pling during full scale operation). The regional water qual-
ity control boards specify in waste discharge requirements
(WDRs) the elements of the land treatment program in-
cluding the dimensions of the treatment zone. The maxi-
mum depth of the treatment zone shall not exceed 5 feet
from the initial soil surface.
4.5 Maine
4.5.1 Liquid Residuals
Direct Discharge to Surface Water
Maine is not currently authorized to implement the federal
NPDES program. EPA Region 1 administers the NPDES
program in Maine. EPA Region 1 develops all NPDES per-
mits for direct discharges to surface waters within Maine
(including the requisite technology-based and water qual-
ity-based effluent limits). When EPA develops the NPDES
permit, Maine must certify that the permit will meet state
surface water quality standards before the permit may be
issued. In addition, direct discharge facilities must also
obtain discharge permits from the state (such permits are
in addition to federal NPDES permits). Such state permits
focus on protecting the quality of Maine surface waters
(as reflected in Maine's surface water classifications).
Maine adopts the federal water quality criteria as its nu-
meric standards for the maximum arsenic levels deemed
to be acceptable in surface waters.21 These levels, which
are summarized in Table 4-8, vary based on the character
of the waterbody as well as on the acute or chronic nature
of the water quality impact.22 Each fresh and salt water
surface water within Maine should meet the correspond-
ing arsenic limit specified. To ensure this occurs, each
NPDES permit issued for a direct discharge to surface
waters in Maine must ensure that the effluent discharged
by that facility does not cause a violation of the correspond-
ing arsenic standard at the point of discharge or in a mix-
ing zone in reasonable proximity to the discharge. Typi-
cally, facilities employ effluent treatment to achieve com-
pliance with NPDES permit limits.
Maine also requires that direct discharge facilities obtain a
discharge permit from the state. These state permits are
intended to ensure, through limiting discharges to the as-
similative capacity of the waterbody, that streams and lakes
can meet their use classifications (classifications exist for
freshwaters and marine/estuarine waters, and include four
freshwater and three saltwater classifications based on
existing water quality and the ability of the water to sup-
port distinct uses). Any standards or conditions imposed
under these state permits appear to be developed on a
case-by-case basis.
In addition to the numeric surface water quality standards
and Maine permit requirements, Maine also imposes nar-
rative surface water quality standards that provide that:
Except as naturally occurs, surface waters must be
free of pollutants in concentrations which impart toxic-
ity and cause those waters to be unsuitable for the
existing and designated uses of the waterbody.
Any discharge of an arsenic residual that is deemed to
violate this narrative standard would be prohibited or lim-
ited through NPDES permit conditions.
Indirect Discharge to a Sanitary Sewer System
Maine does not establish state limits for indirect discharges
(i.e., discharges to public sanitary sewer systems and treat-
"A waste management unit at which liquid and solid waste are discharged to, or
incorporated into, soil for degradation, transformation, or immobilization within
the treatment zone.
"Maine accepts background exceedances from such criteria.
J2Maine allows for the adoption of alternative statewide water quality criteria pro-
vided such criteria are as protective of the designated uses assigned to the wa-
ters within the state as the EPA criteria.
26
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Table 4-8. Maine's Numeric Arsenic Surface Water Quality Standards23
Contaminant Freshwater - Acute Freshwater - Chronic Saltwater - Acute Saltwater - Chronic
Arsenic (total)
0.34 mg/L
0.15 mg/L
0.069 mg/L
0.036 mg/L
ment works). Although local limits may be established by
local sewer authorities or POTWs that administer pretreat-
ment programs, no such limits currently exist. Indirect dis-
charges remain subject to the national general pretreat-
ment standards (e.g., restrictions designed to prevent the
introduction into POTWs of pollutants which will interfere
with or pass through the treatment works).
Underground Injection
Maine administers the UIC program within the state, ex-
cept for on Indian lands. EPA Region 1 administers the
program on Indian lands (see 40 CFR § 147 Subpart U).
Maine regulations provide that Class I wells (deep well in-
jection), Class II wells (injection of fluids associated with
oil and gas production), and Class III wells (injection of
fluids associated with solution mining of minerals) are regu-
lated in a manner consistent with federal requirements
(Maine adopts the applicable federal regulations by refer-
ence). New Class IV wells (injection of hazardous waste
or radioactive waste into or above water-bearing forma-
tion) are prohibited and those in existence are required to
be closed. All other types of discharge by well injection are
subject to licensing under 38 MRSA, § 413(1 -B) and must
be consistent with other applicable statutes and regula-
tions administered by the state. Any subsurface discharge
into or through a Class V well that would cause or allow
the movement of fluid into an underground source of drink-
ing water that may result in a violation of any Maine Pri-
mary Drinking Water Standard, or which may otherwise
adversely affect human health, is prohibited.
Land Disposal
Maine regulations provide that landfills may not accept liq-
uid wastes for disposal.
4.5.2 Solid/Sludge Residuals
Solid Waste Landfill
Maine imposes landfill operating requirements for munici-
pal solid waste disposal facilities. A component of the state
landfill operating requirements is proper leachate manage-
ment. Landfill operators must conduct quarterly monitor-
aAcute limits may not be exceeded for 1 hour in any 3-year period. Chronic limits
may not be exceeded for any 96-hour (4-day) period in any 3-year period.
ing of leachate leak detection systems and leachate qual-
ity. In addition, landfills must conduct semiannual baseline
monitoring for arsenic (and other compounds) in ground
water and surface water, as well as compliance monitor-
ing (to characterize contamination) where there has been
a significant increase in arsenic levels in ground water.
Corrective action is required where contaminants (includ-
ing arsenic) exceed target levels, which are determined
on a site-specific basis.
Hazardous Waste Landfill
Maine is authorized to implement the federal RCRA pro-
gram. As such, Maine imposes the same toxicity charac-
teristic standard as is imposed under federal regulations
(i.e., 5.0 rng/L). With regard to some provisions, Maine
imposes requirements that are more stringent than the fed-
eral requirements. Most notably, Maine requires that any-
one who generates more than 100 kilograms of hazard-
ous waste (per month) must manage that waste in con-
formance with Maine hazardous waste rules (i.e., Maine
does not reduce these requirements for small quantity gen-
erators). In addition, Maine provides that hazardous waste
generators that generate less than 100 kilograms of waste
(per month) mu'st comply with manifest, transport, label-
ing, packaging, and disposal (requires use of a licensed
facility) requirements.
Lagoons
Maine does not explicitly regulate the use of lagoons to
manage nonhazardous wastes (such requirements are
likely determined on a site-specific basis). Maine does
impose requirements applicable to the discontinued use
of lagoons. These provisions include notice, reclamation,
and discharge requirements. In addition, Maine has two
ground water quality classifications, GW-A and GW-B.
Class GW-A is defined as the highest classification and
must be of such quality that it can be used for public water
supplies. These waters must be free of radioactive matter
or any matter that imparts color, turbidity, taste or odor which
would impair usage of these waters, other than that occur-
ring from natural phenomena. Class GW-B is defined as
suitable for all usages other than public water supplies.
Lagoons or surface impoundments cannot cause violations
of these classifications.
Hazardous waste surface impoundments must meet the
federally applicable design standards (i.e., 40 CFR Part
264) as well as following performance standards: no im-
pounded hazardous waste or constituent or derivative may
27
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appear in ground or surface water at a concentration above
background level or above current Maine public health
drinking water standards (including either the maximum
exposure guidelines, or standards for aquatic toxicity,
whichever is most stringent); a leachate detection, collec-
tion, and removal system must be installed; and air, ground
water, and surface water monitoring must be conducted in
accordance with state requirements.
Reuse (Land Application)
Maine regulates the land application and composting of
municipal and industrial sludge and residuals. Land appli-
cation of sludge and residuals is prohibited unless an ap-
proval has been obtained from the Maine Department of
Environmental Protection. Sludge is defined as the semi-
solid or liquid residual generated from a municipal, com-
mercial, or industrial wastewater treatment plant. Land ap-
plication requirements are based on crop (or soil) require-
ments (i.e., utilization), the characteristics of the soil at the
application site, and sludge and residual quality. Residu-
als, such as municipal wastewater treatment plant sludge,
must undergo initial chemical analysis prior to submittal of
an application for land spreading. Arsenic is not one of the
minimum parameters that must be measured during the
initial chemical analysis of sludge; however, it can be added
based on an assessment of the sludge or residual. Nor is
arsenic included in the maximum concentration standards
established for the land application of sludges and residu-
als. Land application of sludge cannot pollute any waters
of the state or result in violation of Maine's primary and
secondary drinking water standards. Land application can-
not occur over significant ground water aquifers or primary
sand and gravel recharge areas. Maine's program for the
land application of sewage sludge is not currently autho-
rized by EPA pursuant to 40 CFR Part 501. Therefore, EPA
remains responsible for permitting facilities managing sew-
age sludge.
4.6 Nebraska
4.6.1 Liquid Residuals
Direct Discharge to Surface Waters
Nebraska is authorized to implement all aspects of the
NPDES program except for the sewage sludge program.
Nebraska has developed designated use numeric water-
quality standards that limit the amount of arsenic that may
"Standards are developed by the Water Quality Division of the Nebraska Depart-
ment of Environmental Quality.
"Designated uses for the state's waterbodies are listed in Title 117, Chapter 6, All
streams are assigned designated uses of aquatic life, agricultural water supply,
and aesthetes. Other designations (i.e., state resource waters, recreation, drink-
ing water supply (after treatment), and industrial water supply) apply to selected
segments only.
be discharged to surface waters.24 These standards are
presented in Table 4-9. Each surface water in Nebraska
that is designated for each of the designated uses25 de-
scribed in Table 4-9 must meet the corresponding arsenic
limit specified (discharges that cause a violation are pro-
hibited). Thus, each NPDES permit issued to a DWTP that
directly discharges pollutants to surface waters in Nebraska
must ensure that the effluent discharged by that facility
does not cause a violation of the corresponding arsenic
standard.
In addition to these numeric water quality standards, Ne-
braska also imposes narrative water quality standards ap-
plicable to surface waters in the state. Under these stan-
dards:
Surface waters shall be free from toxic substances,
alone or in combination with other substances, in con-
centrations that result in acute or chronic toxicity to
aquatic life.
Toxic substances shall not be present in concentra-
tions that result in objectionable tastes or significant
bioaccumulation or biomagnification in aquatic organ-
isms which renders them unsuitable or unsafe for con-
sumption.
Wastes or toxic substances introduced directly or indi-
rectly into public drinking water supplies by human
activity in concentrations that would degrade the use
(i.e., would produce undesirable physiological effects
in humans) shall not be allowed.
Any discharge of an arsenic residual that is deemed to
violate these narrative standards would be prohibited or
limited through NPDES permit conditions.
Nebraska also establishes ground water quality standards
and use classifications, which may be implemented through
various environmental programs or applied directly. These
are discussed under Solid/Sludge Residuals, Lagoons.
Indirect Discharge to a Sanitary Sewer System
Nebraska does not establish state limits for indirect dis-
charges to surface waters (i.e., discharges to public sewer
systems and treatment works). Nor have any local limits
to arsenic been developed to date. Local limits may be
established by local sewer authorities or POTWs that ad-
minister pretreatment programs, and some such limits are
under development. Nebraska regulations provide that no
pretreatment permit may be issued for any indirect dis-
charge from an industrial user (i.e., non-domestic dis-
charger of pollutants to a POTW) which does not assure
compliance with applicable pretreatment standards or re-
quirements and which will otherwise interfere with, pass
through, or be incompatible with a POTWs treatment pro-
cesses, including contamination of sewage sludge. Thus,
indirect discharges of liquid residuals that cause the sew-
28
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Table 4-9. Nebraska's Designated Use Numeric Arsenic Surface Water Quality Standards26
Protection of Aquatic Life/
Protection of Aquatic Life/
Contaminant
Arsenic III
Arsenic V
Fish Consumption - Acute
0.36 mg/L
0.85 mg/L
Fish Consumption - Chronic
0.19 mg/L
0.048 mg/L
Public Water Supply
0.05 mg/L (total)
age sludge generated by the receiving POTW to exceed
the applicable standards are effectively prohibited.
Underground Injection
Nebraska administers the UIC program within the state,
except for on Indian lands. EPA Region 7 administers the
program on Indian lands (see 40 CFR § 147 Subpart CC).
Consistent with the federal UIC requirements, Nebraska
prohibits underground injection that is not conducted pur-
suant to a permit, and prohibits activity that "allows the
movement of fluid containing any contaminant into under-
ground sources of drinking water, if the presence of that
contaminant may cause a violation of any primary drinking
water regulation or the Nebraska Ground Water Protec-
tion Standards, or may otherwise adversely affect the health
of persons" (122-2-001; 122-4-001). Nebraska UIC provi-
sions include construction, mechanical integrity, operating,
monitoring, and reporting requirements, as well as permit-
ting procedures. Thus, activities that would cause the vio-
lation of any primary drinking water regulation, or violation
of Nebraska ground water quality standards, are prohib-
ited.
Nebraska also has a septic tank permitting program. Un-
der this program, septic tank systems must obtain con-
struction and operating permits, although standard sys-
tems for dwellings (i.e., residences) that meet basic set-
back and other criteria are authorized by rule (no separate
permit is required) provided such systems conform to Ne-
braska regulations and do not endanger human health or
cause pollution. Nebraska regulations prohibit surface
water discharges from a septic tank or its soil absorption
system, and require that the state, in implementing these
regulations, must protect the quality of surface and ground
waters in the immediate vicinity of any proposed septic
tank system (Title 124).
Land Disposal
Nebraska prohibits the disposal of bulk or noncontainerized
liquid wastes in a solid waste disposal area unless the
waste is household waste other than septic waste; the
waste is leachate or gas condensate derived from the solid
waste disposal area and the solid waste disposal area is
2SAoute limits may not be exceeded for 1 hour in any 3-year period. Chronic limits
may not be exceeded for any 96-hour (4-day) period in any 3-year period.
designed with a composite liner and leachate collection
system; or the special waste has been approved for dis-
posal. In addition, under Nebraska regulations, containers
holding liquid waste may not be placed in a solid waste
disposal area unless the container is a small container simi-
lar in size to that normally found in household waste; the
container is designed to hold liquids for use other than
storage; or the waste is household waste (Title 132-3-004).
Nebraska also will consider proposals to apply treated
wastewater for irrigation purposes (Title 121-11). The state
has established guidelines for such projects, which must
be approved on a case-by-case basis. The guidelines for
wastewater irrigation proposals include a recommenda-
tion that arsenic levels in any such project not exceed 0.1
mg/L.
4.6.2 Solid/Sludge Residuals
Solid Waste Landfill
Nebraska requires that solid waste management facilities
must hold a permit issued by the state (Title 132-2-001).
Such disposal facilities must be designed and operated at
all times so as to not constitute a hazard, or a threat to
human health or the environment. Nebraska requires that
no solid waste disposal area may cause a discharge of
pollutants into waters of the state, including wetlands, that
violates any Nebraska NPDES requirement. Nor can such
facilities cause the discharge of a nonpoint source of pol-
lution to waters of the state that violates any requirement
of an area-wide or statewide water quality management
plan that has been approved under section 208 or 319 of
the CWA.
For solid waste landfills meeting the standard Nebraska
landfill liner requirements, ground water protection is not
required under landfill regulations. However, Nebraska's
ground water protection standards do apply to landfill man-
agement of waste and, thus, solid waste landfills may not
cause the ground water arsenic level to exceed 0.05 mg/
L. In addition, Nebraska establishes the same ground wa-
ter standard for arsenic (0.05 mg/L) where a landfill is us-
ing an alternative liner at a new or expanding landfill. Where
an alternative liner is used, Nebraska provides that the
facility must ensure that the concentration of arsenic will
not exceed 0.05 mg/L in the uppermost aquifer at the rel-
evant point of compliance (i.e., no more than one hundred
and fifty (150) meters from the solid waste disposal area
unit boundary and shall be located on land owned by the
owner of the solid waste disposal area) (Title 132-3).
29
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Nebraska also has established regulations governing the
management of special waste, which is defined as includ-
ing wastes that require special management to ensure pro-
tection of public health, safety, or the environment due to
the physical, chemical, or biological properties of the waste
(designations are made on a case-by-case basis). No per-
son may dispose of a special waste at any place except a
permitted facility which is operated and maintained in com-
pliance with Nebraska regulations and authorizations, and
which has received written approval from the state for the
disposal of the specific special wastes (Title 132-13-001).
In addition, where special waste is being land applied on a
regular basis for treatment or disposal, construction and
design plans must also include specific measures that will
be taken to protect ground water quality.
Hazardous Waste Landfill
Nebraska's hazardous waste rules generally mirror the
federal regulations. For example, Nebraska adopts the
federal toxicity characteristic of 5.0 mg/Lfor arsenic (Title
128-3-10). Nebraska also adopts the basic federal require-
ments applicable to hazardous waste generators, trans-
porters, and TSDFs, as well as for land disposal restriction
standards.
Lagoons
Nebraska imposes regulations applicable to waste lagoons
(Title 125), as well as ground water protection standards
(Title 118). Nebraska defines waste lagoons as units com-
prised of a shallow body of water in which organic wastes
are decomposed by bacteria in the presence of free oxy-
gen. Such units must be designed for complete retention
of the waste. Nebraska also imposes location, run-on, ac-
cess, minimum location area (3 acres), and closure re-
quirements.
With regard to ground water protection standards, Ne-
braska imposes both numeric and narrative ground water
quality standards. For arsenic, Nebraska provides that
substances introduced by human activity shall not be al-
lowed to enter ground water if such substances would
cause the ground water arsenic level to exceed 0.05 mg/
L. The ground water quality standards are intended to be
the foundation for other regulatory programs that may im-
pact ground water. As such these standards must be imple-
mented in conjunction with other regulatory programs if
such programs could impact ground water, and may be
implemented alone as the basis for remedial action of
ground water contamination if other regulatory programs
do not exist. These standards apply to all ground waters
within Nebraska that are, or have the potential to be, used
as a public or private drinking water source.27
"State ground water classifications GA and GB.
Nebraska also imposes narrative ground water standards
that function to protect ground water quality (Title 118-4-
001). The following narrative standards apply to ground
waters in Nebraska:
Wastes, toxic substances, or any other pollutant (alone
or in combination with other pollutants) introduced di-
rectly or indirectly by human activity shall not be al-
lowed to enter ground water:
If beneficial uses of ground water would be im-
paired or public health and welfare would be
threatened.
If beneficial uses of hydrologically connected
ground waters or assigned uses of surface wa-
ters would be impaired.
Any pollutant introduced directly or indirectly by hu-
man activity that would impair beneficial uses of ground
water due to unacceptable color, corrosivity, odor, or
any other aesthetic characteristic shall not be allowed.
Nebraska also provides for the regulation of potential di-
rect (i.e., point source) discharges of pollutants that may
impact ground water quality. Nebraska rules provide that
in determining regulatory requirements that may be placed
on potential point sources, the state must consider the
ground water classification, vulnerability of the ground water
to pollution, beneficial uses of ground water, characteris-
tics of the potential point source, technical and socioeco-
nomic factors, and other site-specific factors, as neces-
sary (Title 118-09-001). These requirements apply to all
potential point sources for which the Nebraska Department
of Environmental Quality has regulatory authority, includ-
ing but not limited to NF'DES, DIG, POTWs, septic tanks,
lagoons, pretreatment facilities, hazardous waste TSDFs,
and licensed landfills. Remedial action is required if Ne-
braska ground water quality standards are violated due to
point source discharges.
Reuse (Land Application)
Nebraska has both sludge and sewage sludge regulations.
Nebraska defines the term "sludge" as including (but not
limited to) solid, semisolid, and liquid wastes generated
from water supply treatment plants (Title 126-1-041). Ne-
braska requires all persons who land apply sludge or man-
age wastewater treatment facility grit and screenings to
obtain a waste management permit. Such permits must
establish compliance with local, state, and federal require-
ments, duration, compliance schedule, and reporting and
recordkeeping requirements, as well as require commence-
ment of operations within two years after issuance of the
permit.
Nebraska also has in place regulations that address sew-
age sludge management. These rules, which require a
permit where sewage sludge disposal may result in the
30
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pollution of waters within Nebraska, do not apply to drink-
ing water treatment residuals unless such residuals are
mixed with sewage sludge (Title 119-09). Nebraska's sew-
age sludge program is not authorized pursuant to 40 CFR
Part 501.
4.7 New Mexico
4.7.1 Liquid Residuals
Direct Discharge to Surface Water
New Mexico is not currently authorized to implement the
federal NPDES program. EPA Region 6 administers the
NPDES program in New Mexico, developing and issuing
all of the NPDES permits for direct dischargers within New
Mexico (including the requisite technology-based and wa-
ter quality-based effluent limits). When EPA develops the
NPDES permit, New Mexico must certify that the permit
will meet state water quality standards before the permit
may be issued.
New Mexico has developed numeric arsenic water-quality
standards applicable to surface waters.28These standards
are presented in Table 4.10. These surface water quality
standards vary based on the designated use of each wa-
ter body within New Mexico (e.g., domestic water supply,
irrigation, livestock watering).29 Each surface water that is
assigned each of the designated uses described in Table
4-10 should meet the corresponding arsenic limit speci-
fied. To ensure this occurs, each NPDES permit issued for
a direct discharge to surface waters within New Mexico
must ensure that the effluent discharged by that facility
does not cause a violation of the corresponding arsenic
standard at the point of discharge or in a mixing zone in
reasonable proximity to the discharge. Typically, facilities
employ effluent treatment to achieve compliance with
NPDES permit limits.
In addition to these numeric surface water quality stan-
dards, New Mexico also imposes a narrative water quality
standard applicable to waters used as a domestic water
source. Under this standard:
Waters designated for use as domestic water supplies
shall not contain substances in concentrations that
create a lifetime cancer risk of more than one cancer
per 100,000 exposed persons (20 NMAC 6.1.3101).
Any discharge of an arsenic residual that is deemed to
violate this narrative standard would be prohibited or lim-
ited through NPDES permit conditions.
^Standards are developed by the Water and Waste Management Division within
the New Mexico Department of Environment.
""Designated uses of New Mexico waterbodies are listed in 20 NMAC 6.1.2100-
3099.
New Mexico also establishes water quality standards for
ground water with 10,000 mg/L or less TDS. These are
discussed under management of Solid/Sludge Residuals,
Lagoons.
Indirect Discharge to a Sanitary Sewer
New Mexico does not establish state limits for indirect dis-
charges to surface waters (i.e., discharges to public sewer
systems arid treatment works). Local limits may be estab-
lished by local sewer authorities or POTWs that adminis-
ter pretreatment programs. For example, the following
approved local limits for arsenic are imposed by various
POTWs within New Mexico:
Albuquerque-0.051 mg/L
Farmington -1.07 mg/L (and proposed limit of 6.60
mg/L)
Las Cruces - 0.66 mg/L (and proposed limit of 0.06
mg/L)
Santa Fe - 2.74 mg/L
In addition, indirect discharges remain subject to the na-
tional general pretreatment standards (e.g., restrictions
designed to prevent the introduction into POTWs of pollut-
ants which will interfere with or pass through the treatment
works).
New Mexico does have a regulatory program that ad-
dresses the land application of sewage sludge (see dis-
cussion under Solid/Sludge Residuals, Reuse). Therefore,
if the indirect discharge of a liquid arsenic treatment re-
sidual causes the sewage sludge generated by the receiv-
ing POTW to exceed the applicable sewage sludge stan-
dard for arsenic, the POTW is likely to impose restrictions
on the indirect discharge of arsenic.
Underground Injection
New Mexico administers the UIC program within the state,
except for on Indian lands (see 40 CFR § 147 Subpart
GG). New Mexico provides that an effluent disposal well
may only be used pursuant to an approved discharge plan
(20 NMAC 6.2.5101). In addition, under New Mexico rules,
no effluent disposal well, which allows for movement of
fluids into ground water having 10,000 mg/L or less TDS,
may be approved, except where the aquifer has been "des-
ignated" (i.e., approved) under NMAC 6.2.5103 for the in-
jection of contaminants into the ground water. New Mexico
authorizes any person to petition the state to consider such
injection. Where New Mexico approves such injection, it
also imposes a water quality standard applicable to ground
water that limits arsenic levels in ground water having
10,000 mg/L or less TDS to 0.1 mg/L.
31
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Table 4-10. New Mexico's Designated Use Numeric Arsenic
Surface Water Quality Standards
Domestic Water
Supply
0.05 mg/L
(dissolved)
Irrigation
0.10 mg/L
(dissolved)
Livestock
Watering
0.2 mg/L
(dissolved)
The New Mexico UIC program imposes technical criteria
and performance standards that address the following ar-
eas: the area of review (i.e., potentially impacted), correc-
tive action, mechanical integrity, construction requirements,
operating requirements, monitoring requirements, report-
ing requirements, plugging and abandonment of wells, pro-
viding information, and notification regarding specified ac-
tions (20 NMAC 6.2.5200).
Land Disposal
New Mexico prohibits the disposal of bulk or
noncontainerized liquid waste30 at any landfill except when
the liquid waste is household waste other than septic waste;
or, the container holding the liquid waste is a small con-
tainer similar in size to that normally found in household
waste and the container is designed to hold liquids for use
other than storage, and the waste is household waste. New
Mexico requires that some wastes, such as municipal
wastewater sludge, contain no free liquids.
New Mexico also has established requirements that ad-
dress on-site residential and domestic liquid waste disposal
through the use of seepage pits, drainfields, evapotrans-
piration systems, sand mounds, sand filters, and approved
surface applications. These requirements only apply to liq-
uid waste systems that receive two thousand (2,000) gal-
lons or less of liquid waste per day, and that do not gener-
ate discharges that require a UIC Discharge Plan or a
NPDES Permit. Moreover, they do not apply to commer-
cial process wastewaters and, therefore, do not impact
drinking water residual management (20 NMAC 7.3.102-
301).
4.7.2 Solid/Sludge Residuals
Solid Waste Landfill
New Mexico defines DWTP residuals as a solid waste (but
not a sludge) and imposes permit requirements for facili-
ties that land dispose municipal, special, and construction
and demolition wastes. All landfills (except those that qualify
for a small landfill exemption) must conduct ground water
monitoring, which consists of detection monitoring, assess-
ment monitoring, and corrective action, as necessary. Land-
fills must conduct detection monitoring, including monitor-
ing for arsenic. If detection monitoring indicates ground
water arsenic levels have reached 50 percent of the appli-
cable ground water standard for arsenic (i.e., 0.025 mg/
L)31 at the waste unit boundary, assessment monitoring
must be initiated. If monitoring indicates that the arsenic
level exceeds the corrective action level, which is 75 per-
cent of the New Mexico landfill ground water standard for
arsenic (i.e., 0.0375 mg/L) then corrective action must be
undertaken.
New Mexico also imposes restrictions on the landfill dis-
posal of special waste, which is defined as solid wastes
that have unique handling, transportation, or disposal re-
quirements, to assure protection of the environment and
the public health, welfare and safety. Such wastes explic-
itly include treated formerly characteristic hazardous wastes
(TFCH); packinghouse and killing plant offal; asbestos
waste; ash; infectious waste; sludge (except compost which
meets the provisions of 40 CFR Part 503); industrial solid
waste; spill of a chemical substance or commercial prod-
uct; dry chemicals, which, when wetted, become charac-
teristically hazardous; and petroleum contaminated soils.
New Mexico imposes minimum test parameters for landfill
disposal of municipal wastewater sludge (which does not
include DWTP residuals) (20 NMAC 9.1.1109). These pro-
visions require that municipal wastewater sludge be tested
for the following parameters:
i i
No free liquids as determined by Paint Filter Liq-
uids Test (EPA Test Method 9095)
Percent solids
pH: 2.0 to 12.5 (acceptable range)
PCBs: No detectable concentration
TCLP (EPA Test Method 1311) - the maximum al-
lowable concentration of arsenic is 5.0 mg/L
Note that these requirements only impact arsenic residual
management if such residuals are mixed with wastewater
sludge. Under New Mexico rules, owners and operators of
landfills dedicated solely for the disposal of sludge derived
from the treatment of domestic sewage must comply with
the requirements of 40 CFR Part 503.
Finally, New Mexico allows landfills to utilize alternative
liner materials provided such materials are equivalent to
the synthetic or natural materials specified in the state's
regulations. As part of a liner equivalency demonstration,
New Mexico has specified that the maximum allowable
concentration of arsenic at the point of compliance is 0.05
mg/L (20 NMAC 9.1.1110).
"The term liquid waste" is defined as any waste material that is determined to
contain free liquids, defined by the Paint Filter Test, described in 'Test Methods
for Evaluating Solid Waste" contained in Section 1101.
31New Mexico identifies 0.05 mg/L as the landfill ground water standard for arsenic.
32
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Hazardous Waste Landfill
New Mexico largely adopts the federal hazardous waste
regulations by reference. New Mexico adopts the federal
toxicity characteristic (5.0 mg/L), the federal quantity re-
strictions, and the federal standards for TSDFs, including
the federal requirements for hazardous waste landfills.32
Lagoons
New Mexico imposes water quality standards applicable
to ground water, which could be impacted by management
of arsenic treatment residuals in lagoons. Under New
Mexico State regulations, ground water with 10,000 mg/L
IDS or less may not exceed 0.1 mg/L arsenic. With lim-
ited exception, no person may cause or allow effluent or
leachate to discharge so that it may move directly or indi-
rectly into ground water unless he or she is discharging
pursuant to a discharge plan approved by the state. When
a discharge plan has been approved, discharges must be
consistent with the terms and conditions of the plan (20
NMAC 6.2.3104). New Mexico also requires monitoring of
ground water around disposal sites that could potentially
threaten this resource (20 NMAC 6.2.3107).
Reuse (Land Application)
Under New Mexico regulations, the land application of
sludge derived from the treatment of domestic sewage33
must comply with the federal regulations under 40 CFR,
Part 503;34 and any additional requirements imposed by
the state, such as, but not limited to, analytical testing fre-
quencies and parameters, siting criteria, and loading rates.
These restrictions only apply to arsenic drinking water treat-
ment residuals if those residuals were mixed with sewage
sludge and then land applied.
New Mexico's sewage sludge program is not currently
authorized by EPA pursuant to 40 CFR Part 501. How-
ever, New Mexico's rules incorporate by reference the fed-
eral sludge land application standards (i.e., 40 CFR Part
503).
4.8 Nevada
Nevada imposes some specific regulations that address
waste management for drinking water treatment facilities.
MNew Mexico does not adopt §264.301 (1)[sic]. Section 264.301 addresses the
design and operating requirements for hazardous waste landfills. Section
264.301 (a)(1) requires that landfills (except existing portions, new landfills, and
lateral expansions) must have a liner that prevents migration during the active life
of the unit. New landfills and lateral expansions must have double liners.
^Facilities also must meet the definition of a solid waste facility. Such facilities
include public or private facilities used for processing, transformation, recycling or
disposal of solid waste, including landfill disposal facilities, transfer stations, re-
source recovery facilities, incinerators and other similar facilities not specified.
Solid waste facility does not include facilities that handle less than 25 tons per day
dry weight.
"Under Part 503, no land application of sewage sludge may cause the arsenic
level to exceed 75 mg/kg. In addition, where sewage sludge is applied in bulk,
cumulative arsenic loading may not exceed 41 kg/hectare or 41 mg/kg monthly
average. (40 CFR § 503.13.)
Under these regulations:
A supplier of water must provide for the proper dis-
posal of waste from a treatment facility, including sani-
tary waste, sludge, waste from any laboratory, waste
from drainage within the facility and waste resulting
from backwashing.
The discharge of any waste from a treatment facility
must comply with any requirements imposed by the
Division of Environmental Protection.
A supplier of water must locate facilities for the dis-
posal of waste from a treatment facility in such a man-
ner as to avoid any potential contamination of the en-
vironment, including any supply of water.
These requirements apply in addition to, and in conjunc-
tion with, the specific regulatory provisions discussed be-
low.
4.8.1 Liquid Residuals
Direct Discharges to Surface Waters
Nevada is authorized to administer the NPDES program
except for the pretreatment and sludge components of the
program. Nevada develops all NPDES permits for direct
discharges to surface waters within the state (including
the requisite technology-based and water quality-based
effluent limits). Nevada has developed numeric surface
water quality standards for arsenic.35 These standards are
presented in Table 4-11. Each surface water in Nevada
that is designated for each of the specific uses described
in Table 4-11 should meet the corresponding arsenic limit
specified. Thus,.each NPDES permit issued for a direct
discharge to surface waters in Nevada must ensure that
the effluent discharged by that facility does not cause a
violation of the corresponding arsenic standard.
In addition to these numeric surface water quality stan-
dards, Nevada also imposes narrative water quality stan-
dards that provide:
[Surface] waters must be free from substances attrib-
utable to domestic or industrial waste or other control-
lable sources that will settle to form sludge or bottom
deposits in amounts sufficient to be unsightly, putres-
cent or odorous or in amounts sufficient to interfere
with any beneficial use of the water.
[Surface] waters must be free from high temperature,
biocides, organisms pathogenic to human beings,
toxic, corrosive or other deleterious substances attrib-
KStandards are developed by the Nevada Department of Conservation and Natu-
ral Resources, Environmental Protection Division, Water Pollution Section.
33
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Table 4-11. Nevada's Designated Use Numeric Arsenic
Surface Water Quality Standards
Municipal or Aquatic Life
Domestic Water Supply
0.05 mg/L
(dissolved)
Irrigation
0.10 mg/L
(dissolved)
Livestock
Watering
0.2 mg/L
(dissolved)
utable to domestic or industrial waste or other control-
lable sources at levels or combinations sufficient to be
toxic to human, animal, plant or aquatic life or in
amounts sufficient to interfere with any beneficial use
of the water.
Waste from municipal, industrial or other controllable
sources containing arsenic, barium, boron, cadmium,
chromium, cyanide, fluoride, lead, selenium, silver,
copper, and zinc that are reasonably amenable to treat-
ment or control must not be discharged untreated or
uncontrolled into the waters of Nevada [the state also
prohibits uncontrolled discharge into the Colorado
River System]. In addition, the limits for concentrations
of the chemical constituents must provide water qual-
ity consistent with the mandatory requirements of the
1962 Public Health Service Drinking Water Standards.
Nevada also has narrative standards applicable to benefi-
cial uses. For example, one such standard provides that
with regard to aquatic life:
Surface water must be suitable as a habitat for fish
and other aquatic life existing in a body of water.
Any discharge of an arsenic residual that is deemed to
violate any of these narrative standards would be prohib-
ited or limited through NPDES permit conditions.
Indirect Discharge to a Sanitary Sewer System
Although Nevada is not authorized to implement the pre-
treatment program, the state shares responsibility for the
management of this program with EPA Region 9. Local
limits may be established by local sewer authorities or
POTWs that administer pretreatment programs. In addi-
tion, indirect discharges remain subject to the national
general pretreatment standards (e.g., restrictions designed
to prevent the introduction into POTWs of pollutants which
will interfere with or pass through the treatment works).
Underground Injection
Nevada administers the UIC program within the state, ex-
cept for on Indian lands. EPA Region 9 administers the
program on Indian lands (see 40 CFR § 147 Subpart DD).
Consistent with the federal UIC requirements, Nevada pro-
hibits underground injection that is not conducted pursu-
ant to a permit, and provides that applicants for a permit to
inject fluids must satisfy the State Director that the under-
ground injection will not endanger any source of drinking
water. In addition, Nevada regulations provide that no per-
son may inject a fluid which degrades the physical, chemi-
cal, or biological quality of the aquifer into which the fluid is
injected (unless the State Director exempts the aquifer from
this requirement, and EPA Administrator does not disap-
prove the exemption). Nevada UIC provisions include con-
struction, operating, monitoring, and abandonment require-
ments, as well as permitting procedures.36
Land Disposal
An owner or operator of a Class I (municipal solid waste)
landfill site must restrict the types and amounts of liquids
disposed of at that facility except as permitted by the solid
waste management authority. Bulk or noncontainerized liq-
uids may not be placed in a municipal solid waste landfill
unit unless the waste is household waste other than septic
waste; or the waste is leachate or gas condensate from
the municipal solid waste landfill unit and the new or exist-
ing unit or lateral expansion is designed with a composite
liner and system for the collection of leachate as described
in NAG 444.681. Containers holding liquid waste may not
be placed in a municipal solid waste landfill unit unless the
container is a small container similar in size to a container
which would normally be found in household waste; the
container is designed to hold liquids for use other than
storage; and the liquid waste is household waste. For pur-
poses of these requirements, the term "liquid waste" means
any waste material which is determined to contain free liq-
uids as a result of a paint filter liquids test, Method 9095,
described in 'Test Methods for Evaluating Solid Wastes,
Physical/Chemical Methods," EPA Publication No. SW-846.
4.8,2 Solid/Sludge Residuals
Solid Waste Landfills
Nevada, which regulates solid waste management under
state plans and local controls, authorizes three classes of
landfills. Generally, Class I landfills include municipal solid
waste landfills, Class II landfills include small municipal
solid waste landfills with no ground water contamination
and located in areas of low precipitation, and Class III land-
fills include industrial waste landfills. Solid waste landfills
must hold a permit and must conduct ground water moni-
toring program capable of identifying contamination, includ-
ing monitoring for arsenic. Nevada's monitoring program
parallels that imposed under 40 CFR Part 258 (a phased
program that includes detection monitoring, assessment
monitoring, and corrective measures as needed). Nevada
offers flexibility for a landfill to establish alternative moni-
toring parameters for inorganic materials, including arsenic.
And certain monitoring parameters may be eliminated if it
is shown that the detected constituents are not reason-
ably expected to be contained in or derived from the waste
contained in the unit (MAC 444.7487).
""Nevada defines UIC well consistent with federal regulations, and defines "fluid"
as any material or substance which flows or moves whether in a semisolid, liquid,
sludge, gaseous, or other form or state.
34
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Generally, owners or operators of a Class I landfill may not
cause a discharge of pollutants or contaminants from a
municipal solid waste landfill unit into the waters of the
state, including wetlands, which violates any requirements
of the federal CWA, or comparable state law, or cause the
discharge of a nonpoint source of pollution into the waters
of the state which violates any water quality management
that has been approved pursuant to sections 208 or 319
of the CWA or NRS 445A.300 to 445A.730.
Hazardous Waste Landfill
Nevada adopts by reference the federal toxicity character-
istic for arsenic (i.e., 5.0 mg/L). Nevada requires any per-
son who generates, transports, treats, stores, disposes or
otherwise manages hazardous waste to comply with fed-
eral regulations under 40 CFR Part 2, SubpartA, Part 124,
Subpart A and B, Parts 260 to 270, and Parts 273 and 279
as adopted by reference, except as modified by NAC
444.86325, 444.8633 and 444.8634. Nevada regulations
provide that any out-of-state waste deemed hazardous in
the state of origin is a hazardous waste within Nevada,
regardless of whether it is a hazardous waste under RCRA.
Lagoons
Nevada does not impose specific regulations that address
lagoons or surface impoundments. Rather, under its solid
waste disposal regulations, Nevada defines the term "sur-
face impoundment"37 and imposes general standards that
apply to such waste management units. These standards
provide that solid waste systems (including impoundments)
may not be placed in operation unless approved by the
solid waste management authority, and must be operated
in a manner that will not cause or contribute to pollution of
the atmosphere, or surface or ground waters of Nevada.
Nevada does not establish specific ground water quality
standards, but does protect ground water resources
through its mining reclamation and ground water protec-
tion programs (e.g., mining facilities may not degrade
ground water beyond federal or state drinking water stan-
dards).
Reuse (Land Application)
Nevada regulations provide that special wastes, including
sewage sludges, septic tank pumpings and medical wastes,
may be deposited at a disposal site only if provisions for
such disposal are included in the operational plan and ap-
proved by the solid waste management authority. Nevada
is not authorized to implement the federal sewage sludge
program.
37A facility or part of a facility which is a natural topographic depression, man-made
excavation or diked area formed primarily of earthen material or lined with man-
made material, which is designed to hold an accumulation of liquid wastes or
wastes containing free liquids. The term includes holding storage, settling and
aeration pits, ponds and lagoons. The term does not include injection wells (NAC
444.6265).
4.9 Pennsylvania
4.9.1 Liquid Residuals
Direct Discharges of Liquids to Surface Waters
Pennsylvania is authorized to implement the federal
NPDES program except for the pretreatment and sludge
components of the program. Pennsylvania has developed
designated uses for surface waters within the state and
has established water quality criteria designed to protect
those uses.38These criteria, which are summarized in Table
4-12, vary based on the acute or chronic nature of the wa-
ter quality impact. Each surface water within Pennsylva-
nia should meet the corresponding arsenic limit specified.
To ensure this occurs, each NPDES permit issued for a
direct discharge to surface waters in Pennsylvania must
ensure that the .effluent discharged by that facility does
not cause a violation of the corresponding arsenic stan-
dard at the point of discharge or in a mixing zone in rea-
sonable proximity to the discharge. Typically, facilities
employ effluent treatment to achieve compliance with
NPDES permit limits. In addition to the numeric surface
water quality standards, Pennsylvania also imposes a nar-
rative surface water quality standard that provides that:
[Surface] water may not contain substances attribut-
able to point or nonpoint source waste discharges in
concentration or amounts sufficient to be inimical or
harmful to the water uses to be protected or to human,
animal, plant, or aquatic life.
Any discharge of an arsenic residual that is deemed to
violate this narrative standard would be prohibited or lim-
ited through NPDES permit conditions.
Indirect Discharges to a Sanitary Sewer System
Pennsylvania is not authorized to implement the federal
pretreatment program. Rather, EPA Region 3 and Penn-
sylvania implement the program under a cooperative agree-
ment. Nevertheless, Pennsylvania requirements are gen-
erally consistent with the federal standards, including the
prohibition on the indirect discharge (i.e., discharge to
POTWs) of pollutants that would interfere or pass-though
a POTW. Pennsylvania provides that a POTW, in cases
where pollutants indirectly discharged by industrial users
result in interference or pass through and the violation is
likely to recur, must develop and implement specific local
limits. Such limits must ensure renewed or continued com-
pliance with the POTW's NPDES permit or sludge use or
disposal practices.
Underground Injection
Pennsylvania is not authorized to administer the federal
UIC program. EPA Region 3 administers the program within
Pennsylvania (see 40 CFR Subpart NN). The requirements
^Uses and standards are developed by the Department of Environmental Resources,
Water Management Division.
35
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Table 4-12. Pennsylvania's Arsenic Surface Water Quality Criteria39
Contaminant Maximum Concentration -Acute Continuous Concentration - Chronic
Health Criteria
Arsenic (III)
0.36 mg/L
0.19 mg/L
0.05 mg/L
imposed within Pennsylvania are consistent with those
described in Section 3.
Land Disposal
Pennsylvania provides that bulk or noncontainerized liq-
uid waste may not be disposed or processed at a munici-
pal waste landfill. In addition, containers holding free liq-
uids may not be accepted unless the container is less than
1 gallon in size, except as otherwise provided in the mu-
nicipal solid waste permit.
4.9.2 Solid/Sludge Residuals
Solid Waste Landfill
Pennsylvania authorizes municipal, residual and construc-
tion and debris landfills (solid and sludge DWTP residuals
are most likely managed as municipal wastes). A landfill
permit application must contain a description of the chemi-
cal characteristics of ground water quality for each aquifer
in the proposed permit area and adjacent area, based on
at least 1 full year of monitoring data. For municipal land-
fills, this description must be based on quarterly sampling
and analysis from each monitoring well for various param-
eters, including arsenic. For residual landfills, such char-
acterization must be based on at least two quarters of sam-
pling. In addition, a person or municipality operating a
municipal waste landfill or residual waste landfill must con-
duct annual sampling and analysis from each monitoring
well, again including analysis for arsenic.
Hazardous Waste Landfills
Pennsylvania is authorized to implement the federal RCRA
program. Pennsylvania has promulgated requirements that
are generally consistent with the federal hazardous
wasteregulations. Thus, Pennsylvania imposes the same
toxicity characteristic standard as imposed under federal
regulations (i.e., 5.0 mg/L). Pennsylvania provides that
before placing a hazardous waste in or on a land treat-
ment facility, the owner or operator must determine the
concentrations in the waste of any substances which ex-
ceed toxicity characteristic levels.
Lagoons
Pennsylvania has developed requirements applicable to
impoundments generally, as well as specific requirements
applicable to the use of impoundments for the disposal of
residual and hazardous waste based on discussions with
state personnel; it does not appear that DWTP residuals
meet the state definition of residual waste. As for general
requirements applicable to impoundments, persons man-
aging polluting substances in an impoundment must take
necessary measures to prevent the substances from di-
rectly or indirectly reaching waters within Pennsylvania.
Such persons may not operate, maintain or use an im-
poundment for the production, processing, storage, treat-
ment or disposal of polluting substances unless the im-
poundment is structurally sound, impermeable, protected
from unauthorized acts of third parties, and is maintained
so that a freeboard of at least 2 feet remains at all times.
The person or municipality owning, operating or possess-
ing an impoundment has the burden of satisfying state of-
ficials that the impoundment complies with these require-
ments. The requirements described above do not apply to
residual waste40 processing,41 disposal, treatment,42 col-
lection, storage or transportation. Pennsylvania requires
that residual waste disposal impoundments must have a
permit, and that permit applications must include ground
water quality data, including sampling for arsenic. In addi-
tion, no person may not dispose of residual waste at a
residual waste disposal impoundment unless the free liq-
uid fraction of the waste can be readily separated from the
solid fraction and is collected and discharged in accordance
with Pennsylvania law, and the waste will solidify by a
chemical or physical process upon disposal or within the
shortest period of time technologically practicable. With
limited exception, such wastes must solidify prior to clo-
sure.
"Acute limits may not be exceeded (or 1 hour in any 3-year period. Chronic limits
may not be exceeded for any 96-hour (4-day) period in any 3-year period.
"Residual waste includes garbage, refuse, other discarded material or other waste,
including solid, liquid, semisolid, or contained gaseous materials resulting from
industrial, mining, and agricultural operations and sludge from an industrial, min-
ing or agricultural water supply treatment facility, wastewater treatment facility, or
air pollution control facility, if it is not hazardous. Based on discussions with Penn-
sylvania DEP personnel, DWTP residuals are regulated as municipal wastes and
not residual wastes under state regulations.
41Volume reduction or conversion for off-site reuse.
42A method, technique or process, including neutralization, designed to change the
physical, chemical, or biological character or composition of waste to neutralize
the waste or to render the waste nonhazardous, safer for transport, suitable for
recovery, suitable for storage or reduced in volume. The term includes an activity
or process designed to change the physical form or chemical composition of waste
to render it neutral or nonhazardous.
36
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Finally, impoundments used to manage hazardous waste
are subject to comprehensive regulations, including re-
quirements addressing impoundment siting, design, liner
specifications, leachate management, ground water moni-
toring, operation, closure, and financial responsibility.
Reuse (Land Application)
Pennsylvania has established regulations that address the
land application of sewage sludge and the beneficial use
of sewage sludge through land application, but not explicit
requirements that apply to the land application of DWTP
sludge. Pennsylvania is not authorized to implement the
federal sewage sludge program requirements.
Under Pennsylvania's sewage sludge beneficial use re-
quirements, sewage sludge may only be land-applied pur-
suant to a state permit and consistent with specified stan-
dards, which are consistent with 40 CFR Part 503 stan-
dards. No sewage sludge may be applied to the land if the
concentration of arsenic exceeds 75 mg/kg. In addition,
sewage sludge applied to agricultural land, forest, a public
contact site or a reclamation site may not exceed a cumu-
lative arsenic loading rate of 41 kg/hectare (36 pounds per
acre). Finally, if sewage sludge is applied to a lawn or a
home garden, or is sold, given away or otherwise distrib-
uted in a bag or other container for application to the land,
the concentration of arsenic in the sewage sludge may not
exceed a concentration of 41 mg/kg (monthly average).
Under Pennsylvania's general sewage sludge provisions,
a permit is required but no numeric standards are imposed.
Rather, Pennsylvania provides that the operator may not
cause or allow a point or nonpoint source discharge of
pollution from or on the facility to surface waters of the
state. Land application facilities must be operated to pre-
vent and control surface and ground water pollution. In
addition, such facilities may not cause or allow a discharge
of a contaminant into ground water except as authorized
by a state permit.
37
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5. References
Arizona Administrative Code, Title 18, Environmental Qual-
ity (1998).
American Water Works Association. (AWWA). 1990. Wa-
ter Quality and Treatment. McGraw-Hill, New York.
American Water Works Association, American Society of
Civil Engineers. (AWWA, ASCE). 1998. Water Treat-
ment Plant Design. McGraw-Hill, New York.
Brewster, Michael D. Removing Arsenic from Contami-
nated Wastewater. [need rest of citation] November
1992.
California Code of Regulations, Titles 14 - Natural Re-
sources; 17 - Public Health; R3 - Waters; 27 Environ-
mental Protection (1998).
DPRA, Inc. 1993. Draft Final Water System Byproducts
Treatment and Disposal Cost Document. Prepared
for EPA Office of Ground Water and Drinking Water.
Driehaus, W., M. Jekel, and U. Heldebrandt. Granular fer-
ric hydroxide a new adsorbent for the removal of ar-
senic from natural water. J Water SFtT - Aqua. Vol.
47. No. 1. pp. 30-35. 1998.
Hecht P.M., D.J. Hiltebrand, and J. Lowry. 1993. Arsenic
Removal by Anionic Exchange. AWWA Annual Con-
ference, San Antonio.
Johnson, M.D., R.M. Wingo, and C. Harrelson. 1998. De-
velopment of Arsenic Remediation Technology in Drink-
ing and Waste Waters Using Ferrate. Proceedings Joint
Conference on the Environment, Albuquerque, NM,
March 31 -April 1, 1998. WERC Administrative Of-
fice, New Mexico State University, pp. 355-360.
Koorse, S.J. 1993. Review of Water Treatment Plant Re-
siduals Laws and Regulations. Prepared for the Ameri-
can Water Works Association.
Lauf, Gregory F. and Mark A. Waer. 1994. Arsenic Removal
Using Potassium Permanganate. Proceedings of the
1993 Water Quality Technology Conference, Part II,
Miami, FL. American Water Works Association, pp.
1025-1038
Maine Administrative Code, Titles 444-445 (1998).
Montgomery, James M. 1985. Water Treatment Principles
and Design. John Wiley and Sons, NY.
Nebraska Administrative Code, Titles 117-457 (1998).
Nevada Administrative Code, Title 444 (Rev. 2000).
New Mexico Administrative Code, Title 20 - Environmental
Protection (1998).
Pennsylvania Administrative Code, Title 25 - Environmen-
tal Protection (1998)
Science Applications International Corporation and HDR
Engineering, Inc. (SAIC and HDR) 1994. Summary of
Arsenic Treatment Workshop January 18,1994. Pre-
pared for U.S. Environmental Protection Agency, Of-
fice of Ground Water and Drinking Water.
USEPA. 1998. Draft Cost and Technology Document for
the Ground Water Rule. Office of Ground Water and
Drinking Water, Washington, DC.
USEPA, 1996. Technology Transfer Handbook: Manage-
ment of Water Treatment Residuals. Prepared by the
Office of Research and Development. EPA/625/R- 957
008.
USEPA, 1993. Treatment and Occurrence - Arsenic in
Potable Water Supplies. Prepared by Malcolm Pirnie,
Inc for the Office of Ground Water and Drinking Water,
Washington, DC.
Vagliasindi, Federico G.A. and Mark M. Benjamin. 1997.
Arsenic Behavior in Packed Bed Adsorption Reactors:
Media Performance vs Water Quality Composition.
Proceedings of the 1997 American Water Works As-
sociation Annual Water Research Conference, June
15-19, pp. 443-456
Waypa, John J., Meriachem Elimelech, and Janet G.
Hering. Arsenic removal by RO and NF membranes.
Journal AWWA. 89(10): 102-114. October 1997.
38
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