SEPA
United States
Environmental Protection
Agency
A System's Guide to the
Identification and Disposal of
Hazardous and Non-
Hazardous Water Treatment
Plant Residuals
Drinking water systems producing solid waste are required under the Resource Conservation and Recovery Act
(RCRA) to determine whether that waste is hazardous. These requirements are described in this document in
summary form only; you need to consult the statutory and regulatory provisions that are applicable to the waste you
generate or manage in order to determine the requirements with which you must comply. This document also provides
additional recommendations and information on possible options; these are not regulatory requirements and are provided
for your information only. EPA will continue to review and update this Guide as necessary and appropriate.
RCRA's definition of solid waste (40 CFR 261.2) is broad,1 encompassing all wastes that a water treatment plant (WTP)
would produce, including liquid residuals, solid residuals, and sludge. Although most water systems can avoid generating
hazardous wastes, some WTP residuals may contain certain contaminants, such as arsenic, in high enough concentrations
to be classified as hazardous. For additional information on RCRA, see n>n>n>.epa.gov/ epaosmr/ osif/ lam-reg.htm.
1 Solid waste includes any garbage; refuse; sludge from a wastewater treatment plant, water supply treatment plant, or air pollution control facility;
and other discarded material, including solid, liquid, semisolid, or contained gaseous material, resulting from industrial, commercial, mining, and
agricultural operations and from community activities.
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WTP Residuals
The following sections summarize the steps you must take to determine whether
your residuals are hazardous, your generator status if you are generating or storing
hazardous waste, and your disposal options for hazardous and non-hazardous
residuals.
STEP 1: WASTE IDENTIFICATION
Hazardous waste regulations vary
from state to state. It is important
to check with your primacy agency
to determine whether you need to
meet additional requirements.
WTP waste identification is a two-step process:
1. Determine whether the waste is hazardous using your
knowledge of the waste generation process, analytical
testing, or a combination of both. See Decision Tree 1
on page 4 for additional information on hazardous
waste identification.
• Process knowledge is detailed information on the
processes that create wastes (i.e., does the process
concentrate or dilute the waste?). It can be obtained
by reviewing treatment schematics and plans,
published waste analysis data or studies on similar
treatment processes, or data from other treatment
facilities, among other things. Note that if you use
process knowledge alone to characterize the waste,
you will be held responsible for any inaccurate
determinations.
• Analytical testing may involve leachate tests such
as the Toxicity Characteristic Leaching Procedure
(TCLP) (EPA Method 1311), which is designed to
determine the mobility of both organic and inor-
ganic analytes present in liquid, solid, and
multiphasic wastes. The TCLP predicts if hazard-
ous components of a waste are likely to leach out
and become a threat to public health or the environ-
ment. Testing should always be done by a qualified
laboratory and while analytical testing can be more
expensive, it usually provides more accurate infor-
mation on waste characteristics. Table 1 contains
maximum concentrations for the toxicity character-
istics for inorganic contaminants.
For more information on process knowledge and analytical testing, see n>n>n>.epa.govl epaosmrl non-hn>l industdl chapters!
chap2.pdf and n>n>n>.epa.govl sn>-8461 index.htm.
Mixed Waste
Mixed waste "contains both hazardous waste and source... or
byproduct material subject to the Atomic Energy Act [AEA]..."
(42 USC 6903.41). Mixed waste is regulated under both RCRA
and AEA, and although highly unlikely, WTPs generating hazard-
ous waste could have a mixed waste if the residuals also contain
more than 0.05 percent by weight of uranium or thorium (i.e.,
source material).
A system generating hazardous waste does not have mixed waste
if the amount of source material generated is an "unimportant
quantity" (uranium or thorium makes up less than 0.05 percent by
weight of the material), or if the waste contains only radium since
radium is not considered source or by-product material when
present in water treatment residuals unless it co-occurs with
licensable source material such as uranium. Your primacy agency
may have additional regulations for water treatment plant residuals
containing radium.
Hazardous wastes containing source material exceeding the
"unimportant quantity" limits, must be disposed of at a facility
authorized to accept mixed waste. Because there are extremely
limited mixed waste disposal options, generation of a mixed waste
should be avoided if at all possible.
For additional information, see EPA's A System's Guide to the
Management of Radioactive Residuals from Drinking Water Treatment
Technologies (EPA 816-F-06-012) or contact your primacy agency.
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Table 1: Maximum Concentration of Inorganic
Contaminants for the Toxicity Characteristic
2. Determine if your hazardous and/or non-hazardous waste
contains any "free liquids" by having a lab perform the Paint
Filter Liquids Test (PFLT) (EPA SW 846 Method 9095). Land-
fills cannot accept waste containing free liquids and therefore
you will need to use an intermediate processing method (such as
dewatering) to remove any liquids. Your system will need to find
an appropriate method for disposing of the liquid residuals
generated by the intermediate processing.
If your system is producing non-hazardous wastes, your disposal
options for solid residuals are regulated under RCRA Subtitle D,
while hazardous solid wastes are regulated under RCRA Subtitle
C. Disposal options for both non-hazardous and hazardous
liquids are regulated under the Safe Drinking Water Act (SDWA)
Underground Injection Control (UIC) provisions or the Clean
Water Act (CWA) regulations. See Step 3 for more information
on disposal options.
STEP 2: DETERMINE YOUR GENERATOR STATUS AND REQUIREMENTS
In accordance with RCRA, hazardous waste generators are classified into categories based on the amount of hazardous
waste produced monthly and the amount of hazardous waste stored on-site. Your generator status determines your
requirements. See Table 2, below, for the
definition of each generator group. Table 2: Generator Status and Requirements
Contaminant
Arsenic
Barium
Cadmium
Chromium
Lead
Mercury
Silver
Regulatory Level
(mg/L)
5.0
100.0
1.0
5.0
5.0
0.2
5.0
Note: See 40 CFR 261.24 for other contaminants.
If you have obtained CESQG status, and you
exceed either the generation or the storage
limit in any given month, you will lose your
CESQG status and must comply with more
stringent requirements for SQGs or LQGs (40
CFR262.10(b)).
Status
Conditionally Exempt Small
Quantity Generator (CESQG)
Small Quantity Generator (SQG)
Large Quantity Generator (LQG)
Generation
< 100 kg
100-1,000 kg
> 1,000 kg
Storage
< 1,000 kg
1,000-5,999 kg
> 6,000 kg
CESQGs are required under RCRA (40 CFR 261.5) to:
1. Identify all hazardous waste that is generated.
2. Comply with the storage limit requirement (less than 1,000 kg) and maintain an inventory to track the amount of waste
generated each month and stored on-site.
3. Ensure proper on-site or off-site waste treatment or disposal at a:
• Licensed primacy agency hazardous waste facility
• Permitted or interim status hazardous waste Treatment, Storage, and Disposal Facility (TSDF)
• Primacy agency permitted, licensed, or registered solid waste disposal facility (including a municipal solid waste
landfill)
• Recycling facility
• Universal waste facility
Not all primacy agencies recognize the CESQG category. Contact your primacy agency's drinking water or hazardous
waste program for more information.
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Decision Tree 1: Hazardous Waste Determination
Is the solid waste excluded from Yes
regulation under 40 CFR 261 /
No
Is the solid waste listed in 40 CFR 261
Subpart D, or is it a mixture that
contains a waste listed in Subpart D?2
^_
Yes
/—
Has the waste or mixture been
excluded from the lists in Subpart D
or definitions in 40 CFR 26133 in
accordance with 40 CFR 260.20 and
40CFR260.22?4
Does the waste exhibit any of the
characteristics specified in 40 CFR
261 Subpart C (i.e.Jgnitability,
corrosivity, reactivity, or toxicity)?
Yes
Hazardous waste;
land disposal subject
to Subtitle C
No
No
Not a hazardous waste;
land disposal subject
to Subtitle D
1 40 CFR 261.4(b) lists solid wastes that are excluded from regulations as hazardous waste. Note that 40 CFR 261.4(a) lists materials that are not
solid wastes and are thus excluded from regulation under RCRA. These materials include: domestic sewage; CWA point source discharge; irrigation
return flow; Atomic Energy Act (AEA) source, special nuclear, or by-product material; or, in-situ mining waste.
2 40 CFR 261 Subpart D lists hazardous wastes subject to RCRA regulation.
3 40 CFR 261.3 includes the definition of hazardous waste as a solid waste that is not excluded from regulation in 40 CFR 261.4(b), and is listed in
40 CFR Subpart D, or exhibits a characteristic of hazardous waste identified in 40 CFR Subpart C (i.e., ignitability, corrosivity, reactivity, or toxicity).
4 40 CFR 260.20 and 260.22 provide an opportunity for any person to petition the EPA Administrator to modify or revoke any part of 40 CFR 261
(including a waste that is excluded from a particular facility from the lists in 40 CFR Subpart D).
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STEP 2, continued
If you generate or store enough waste to be considered a SQG or LQG, you will be subject to further RCRA regulations
(40 CFR 262). These include: obtaining an EPA identification number (generally from the primacy agency); complying
with waste accumulation and storage requirements; developing emergency plans; training employees; following the mani-
fest system and Department of Transportation (DOT) requirements for off-site hazardous waste shipments; and
recordkeeping and reporting requirements. SQGs and LQGs that plan on storing waste beyond certain time limits must
also obtain a RCRA storage permit. Time limits vary according to waste quantity and factors, as described in 40 CFR
262.34.
If your system is a CESQG, you are not required to comply with most of the regulations described above. However, you
should follow safe management practices when storing hazardous waste on-site, including:
• Carefully labeling and sealing hazardous waste containers
• Maintaining and frequently inspecting the areas where hazardous waste is stored to minimize the chance of leaks
• Posting emergency response telephone numbers and making sure that there is an easily accessible telephone in or
near the storage facility
• Ensuring that system staff are aware of the dangers and are properly trained to handle hazardous waste
• Preparing containers for transportation by packaging, labeling, and marking them according to DOT regulations (49
CFR 172; see www.access.gpo.govl nara I cfrI waisidx_02l49cfr172_02.html)
Transporting Waste
The transporter or disposal facility may require CESQGs to have an EPA Hazardous Waste
Generator ID number. For more information on this, see EPA's "Notification of Regulated
Waste Activity Instructions and Form Booklet" at iviviv.epa.gov/epaosiver/ha^ivaste/data/
form8700/forms, htm.
CESQGs may not be required to prepare a Uniform Hazardous Waste Manifest for the waste
transporter. However, the manifest is a good record of your system's hazardous waste
disposal and transportation activities. Contact your primacy agency for information on
licensed hazardous waste transporters and see: iviviv.epa.gov/epaosiver/ha^ivaste/gener/manifest.
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STEP 3: DISPOSAL
The table below includes disposal options for hazardous and non-hazardous WTP residuals. Your disposal options
solid, the type and concentration of contaminants, the volume of waste produced, etc.); and, federal, state, and
Liquid Residuals (Brine, Backwash Water, Rinse
Disposal Option
Discharge directly to
surface waters of the U.S. 1
Discharge to a Publicly
Owned Treatment Works
(POTW)
Injection to a Class I UIC
well
Injection to a Class V
UIC well
Waste Type
Non-hazardous
Hazardous & non-
hazardous
Hazardous, non-
hazardous, and
radioactive 2
Non-hazardous, non-
radioactive
Applicable
Authority
CWA
CWA
SDWA - UIC
• Your system must have a
Elimination System (NPDES)
• You must meet Pretreatment
Technically Based Local Limits
or the POTW
• Waste mixed with domestic
system to a POTW is not
waste under RCRA
• May be an option for hazardous
few Class I facilities accept
generated off-site
• Wells have stringent protective
• Not an option for wastes
Solid Residuals (Spent Resins, Spent
Disposal Option
Municipal & industrial
landfills
Hazardous waste landfill
Waste Type
Hazardous & non-
hazardous
Hazardous & non-
hazardous
Applicable
Authority
RCRA
RCRA
• Waste cannot contain free liquids
• Solids may need to be dewatered
• Waste cannot contain free liquids
• Solids may need to be dewatered
1 Direct discharges subject to NPDES permits are not solid or hazardous waste under RCRA. Wastewater that is stored
the definition in 40 CFR 260.10 would be exempt from RCRA permitting requirements.
2 In accordance with UIC regulations (10 CFR 20 Appendix B, Table 2, Column 2), EPA considers wastes with the
300 pCi/L for uranium.
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will depend on the availability of waste disposal facilities; the characteristics of the waste (i.e., liquid vs.
local regulations. It is important to check with your primacy agency before choosing any disposal options.
Water, Acid Neutralization Water, Concentrate)
Key Considerations
National Pollutant Discharge
permit
An appropriate and accessible receiving waterbody must be available
Program prohibitions and the
^TBLLs) established by your state
sewage that passes through a sewer
considered a solid or hazardous
The POTW can refuse to accept waste that would interfere with or
pass through the POTW treatment process and cause a violation of
the POTWs NPDES permit
Your system must meet any POTW requirements and state permitting
requirements
and radioactive wastes but very
hazardous or mixed waste
requirements
• Can be expensive to construct, operate, and monitor
• Acceptable geology not always available
• States may be more stringent or may prohibit such class of injection
well
considered hazardous
• Most likely not an option for radioactive waste because demonstration
of the non-endangerment standard (40 CFR 144.12) for shallow
injection will be difficult
Filter Media, Spent Membranes, Sludge)
Key Considerations
prior to disposal
• Hazardous waste from CESQGs may be disposed of in municipal or
industrial landfills that meet certain design regulations
prior to disposal
Certain generator classes must meet Land Disposal restrictions
before discharge is a solid waste under RCRA and may be a hazardous waste; however, wastewater treatment tanks that meet
following concentrations of radium and uranium to be radioactive: 60 pCi/L for radium-226, 60 pCi/L for radium-228, and
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Resources
Documents
• Guide for Industrial Waste Management, EPA 530-R-03-001, April 2003
(www.epa.gov/epaoswer/non-hw/industd/guide.htm)
• How Does RCRA Work?, EPA 530-E-OO-OOlc, October 2000
(www.epa.gov/epaoswer/general /man ag-hw/eOO-OOlc.pdf)
• What Makes a Waste Hazardous?, EPA 530-E-OO-OOle, October 2000
(www.epa.gov/epaoswer/general/manag-hw/eOO-001e.pdf)
• RCRA Orientation Manual, EPA 530-R-02-016, January 2003
(www.epa.gov/epaoswer/general/orientat)
• Reducing Risk from Waste, EPA 530-K-97-004, September 1997
(www.epa.gov/epaoswer/general/risk/risk.htm)
• Department of Labor, Occupational Safety and Health Administration Hazardous Waste Standards
(www.osha.gov/SLTC/hazardouswaste/standards.html)
Web Sites
• EPA: www.epa.gov
• EPA Office of Ground Water and Drinking Water: www.epa.gov/safewater
• EPA Office of Solid Waste: www.epa.gov/osw
• EPA Office of Air and Radiation: www.epa.gov/radiation
• EPA Office of Wastewater Management, NPDES: cfpub.epa.gov/npdes
• RCRA Online: www.epa.gov/rcraonline
• Regulations and Standards - RCRA: wwwepa.gov/epaoswer/osw/laws-reghtm#RCRA
• Underground Injection Control: www.epa.gov/safewater/uic.html
• Paint Filter Liquids Test: www.epa.gov/epaoswer/hazwaste/test/pdfs/9095a.pdf
• Department of Transportation, Office of Hazardous Materials Safety: hazmat.dot.gov
• U.S. Nuclear Regulatory Commission: www.nrc.gov
Safe Drinking Water Hotline
1-800-426-4791
Office of Water (4606M)
EPA816-F-06-011
www.epa.gov
August 2006
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