United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5305W)
EPA530-R-97-059
PB98-108145
November 1997
xvEPA
RCRA, Superfund & EPCRA
Hotline Training Module
Introduction to:
Land Disposal Units
(40 CFR Parts 264/265, Subparts K, L, M, and N)
Updated July 1997
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DISCLAIMER
This document was developed by Booz-Allen & Hamilton Inc. under contract 68-WO-0039 to EPA. It is
intended to be used as a training tool for Hotline specialists and does not represent a statement of EPA
policy.
The information in this document is not by any means a complete representation of EPA's regulations or
policies. This document is used only in the capacity of the Hotline training and is not used as a reference
tool on Hotline calls. The Hotline revises and updates this document as regulatory program areas change.
The information in this document may not necessarily reflect the current position of the Agency. This
document is not intended and cannot be relied upon to create any rights, substantive or procedural,
enforceable by any party in litigation with the United States.
RCRA, Superfund & EPCRA Hotline Phone Numbers:
National toll-free (outside of DC area) (800) 424-9346
Local number (within DC area) (703) 412-9810
National toll-free for the hearing impaired (TDD) (800) 553-7672
The Hotline is open from 9 am to 6 pm Eastern Time,
Monday through Friday, except for federal holidays.
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50272-101
REPORT DOCUMENTATION
PAGE
• 1. REPORT NO.
0 EPA530-R-97-059
2.
4. Title and Subtitle
RCRA, SUPERFUND, AND EPCRA HOTLINE TRAINING NODULE: INTRODUCTION TO
LAND DISPOSAL UNITS (40 CFR PARTS 264/265, SUBPARTS K, L, N, N)
0 5. Report Date
0 NOVEMBER 1997
6.
7. Author(s)
8. Performing Organization Rept. No
9. Performing Organization Name and Address
U.S. EPA
OFFICE OF SOLID WASTE
401 M STREET, SW
WASHINGTON. DC 20460
0 10. Projeet/Task/Work Unit No.
o
• 11. Contract(C) or GrantCG) No.
* 68-WO-QQ39
0 (G)
12. Sponsoring Organization Name and Address
BOOZ-ALLEN & HAMILTON
4330 EAST WEST HIGHWAY
BETHESDA, MARYLAND 20814
° 13. Type of Report & Period Covered
0 TRAINING - UPDATED 7/97
O
0 14.
15. Supplementary Notes
16. Abstract (Limit: 200 words)
ONE OF A SERIES OF NODULES DEVELOPED AS A TRAINING TOOL FOR HOTLINE SPECIALISTS. PROVIDES AN OVERVIEW OF THE REQUIRE-
MENTS FOR LANDFILLS, SURFACE IMPOUNDMENTS, WASTE PILES, AND LAND TREATMENT UNITS. SUMMARIZES THE DIFFERENCES BETWEEN
INTERIM STATUS (PART 265} AND PERMITTED (PART 264} STANDARDS FOR LAND DISPOSAL UNITS. DEFINES "SURFACE IMPOUNDMENT"
AND DISTINGUISHES SURFACE IMPOUNDMENTS FROM TANKS. DESCRIBES SURFACE IMPOUNDMENT RETROFITTING AND RETROFITTING VARIANCE
PROCEDURES. EXPLAINS THE CONNECTION BETWEEN LAND DISPOSAL STANDARDS, POST-CLOSURE, AND GROUNDWATER MONITORING. THE
INFORMATION IN THIS DOCUMENT IS NOT A COMPLETE REPRESENTATION OF EPA'S REGULATIONS OR POLICIES, BUT IS AN INTRODUCTION
USED FOR HOTLINE TRAINING PURPOSES.
17. Document Analysis a. Descriptors
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement
RELEASE UNLIMITED
• 19. Security Class (This Report}8 21. No. of Pages
° UNCLASSIFIED ° 13
• 20. Security Class (This Page) • 22. Price
° UNCLASSIFIED ° 0.00
(See ANSI-Z39.18)
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
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LAND DISPOSAL UNITS
CONTENTS
1. Introduction... 1
2. Regulatory Summary 3
2.1 Surface Impoundments 3
2.2 Waste Piles ., 6
2.3 Landfills 8
2.4 Land Treatment Units 10
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Land Disposal Units -1
1. INTRODUCTION
Subtitle C of the Resource Conservation Recovery Act (RCRA) creates a cradle-to-
grave management system for hazardous waste to ensure proper treatment, storage,
and disposal in a manner protective of human health and the environment. Under
RCRA §3004(3), Congress authorized EPA to promulgate regulations establishing
design and operating requirements for land disposal units (LDUs). The
requirements are intended to minimize pollution resulting from the disposal of
hazardous waste in or on the land. The statute lists nine types of LDUs. RCRA
§3004(k) defines land disposal as placement of hazardous waste in any of the
following:
• Landfill • Salt dome formation
• Surface impoundment • Salt bed formation
• Waste pile • Underground mine
• Injection well • Underground cave
• Land treatment facility
EPA has promulgated unit-specific technical standards for four of these LDUs within
the treatment, storage, and disposal facility (TSDF) requirements of Parts 264/265.
This module provides an overview of the requirements for these four LDUs:
landfills, surface impoundments, waste piles, and land treatment units. LDUs that
do not qualify as one of these units are considered miscellaneous units (see the
module entitled Miscellaneous Units for more details).
When you have completed this module, you will be able to summarize the land
disposal unit standards and list the relevant statutory and regulatory citations.
Specifically, you will be able to:
• Cite the statutory and regulatory minimum technological requirements
• Summarize the differences between interim status (Part 265) and permitted
(Part 264) standards for land disposal units
• Find the definition of "surface impoundment" and distinguish surface
impoundments from tanks
* Describe surface impoundment retrofitting and retrofitting variance
procedures
• Explain the connection between land disposal unit standards, post-closure,
and groundwater monitoring.
Use this list of objectives to check your knowledge of this topic after you complete
the training session.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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2 - Land Disposal Units
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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Land Disposal Units - 3
2. REGULATORY SUMMARY
Regulations governing surface impoundments, waste piles, land treatment units,
and landfills appear under Subparts K through N of Parts 264/265. The standards for
permitted and interim status units address, among other things, design and
operating requirements, including liners and leachate collection and removal
systems (LCRS); closure and post-closure requirements; and special standards for
ignitable, reactive, and dioxin-containing wastes. In addition to these unit-specific
requirements, LDUs managing hazardous waste are subject to the general facility
standards found in Subparts A through E of Parts 264/265, as well as the appropriate
groundwater monitoring, closure and post-closure, and financial assurance
requirements.
For each unit discussed, this module addresses five topic areas: design and
operation, inspections, response actions, closure and post-closure, and special issues.
This format will enable you to compare and contrast the regulations for each unit.
2.1 SURFACE IMPOUNDMENTS
Subpart K of Parts 264/265 contains the design and operating standards for surface
impoundments used to treat, store, or dispose of hazardous waste. Surface
impoundments are very similar to landfills in that both units are either a natural
topographic depression, man-made excavation, or diked area formed primarily of
earthen materials, such as soil (although the unit may be lined with man-made
materials). The units are, however, very different in their use. Surface
impoundments are generally used for temporary storage or treatment, whereas a
landfill is an area designated for final waste disposal. Therefore, while the design
and operating standards are very similar, the closure and post-closure standards
differ.
Most of the design, operating, and inspection requirements are, in fact, very similar
for surface impoundments, waste piles, and landfills. The requirements are
discussed in detail in this section, with successive sections referring to this section
for specifics.
DESIGN AND OPERATION
In developing design and operation requirements for surface impoundments (as
well as landfills and waste piles), EPA adopted a regulatory goal of minimizing the
formation and migration of leachate to the adjacent subsurface soil, groundwater,
and surface water.
These comprehensive technical requirements for surface impoundments are the
minimum technological requirements (MTRs) mandated by RCRA §§3004(o)(l)(A)
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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4 - Land Disposal Units
and 3004(o)(4). These sections require a double liner, a leachate collection and
removal system (LCRS), and a leak detection system (§§264.221(c) and 265.221(a)).
These MTRs apply to all new units, lateral expansions, and replacement units for
which construction (or reuse) commences after July 29, 1992. New, lateral
expansion, and replacement units for which construction (or reuse) began between
July 15,1985, and July 29,1992, were required to have only the double liner and
LCRS. Also, certain surface impoundments not subject to these MTRs are subject
only to single liner requirements (§264.221 (a)).
The double liner system consists of a top liner to prevent migration of hazardous
constituents into the liner and a composite bottom liner consisting of a synthetic
geomembrane and three feet of compacted soil material. The unit must also be
equipped with an LCRS, which also serves as the leak detection system. The LCRS,
along with the leak detection system drainage layers, must be designed with a
bottom slope of at least one percent, be made of materials chemically resistant to the
wastes placed in the unit, and be able to remove the liquids at a specified minimum
rate. The. LCRS itself must be designed to collect liquids in a sump and subsequently
pump out those liquids. In addition to the performance and design requirements,
the LCRS must be located between the liners immediately above the bottom
composite liner, enabling the LCRS to collect the largest amount of leachate, while
also representing the most efficient place to identify leaks.
A surface impoundment must also be designed to prevent the flow of liquids over
the top of an impoundment (or overtopping) and ensure the structural integrity of
any dikes. Also, §264.222 requires that the owner or operator establish a site-specific
leachate flow rate, called the action leakage rate (ALR), to indicate when each
regulated unit's system is not functioning properly.
None of these technologies will be effective if the impoundment is installed
improperly or constructed of inferior materials. To ensure that a surface
impoundment meets all technical criteria, EPA requires a construction quality
assurance (CQA) program. The CQA program requires a CQA plan which identifies
how construction materials and their installation will be monitored and tested and
how the results will be documented (§264.19). The CQA program is developed and
implemented under the direction of a registered professional engineer, who must
also certify that the CQA plan has been successfully carried out and that the unit
meets all specifications before any waste may be received in the unit.
INSPECTION
In addition to the general inspection requirements found at §§264/265.15, there are
two types of specific inspections required at LDUs. The first inspection requirement
addresses the design and structural integrity of the unit (§264/265.226). The
owner/operator must inspect liners and covers for any problems after construction
or installation and continue inspections weekly and after storms to monitor for
evidence of deterioration, malfunctions, improper operation of overtopping
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hofline training purposes.
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Land Disposal Units - 5
systems, sudden drops in the level of the impoundment contents, and severe
erosions of dikes and other containment devices.
In the second inspection requirement, owners/opera tors must monitor leak
detection sumps at least weekly to measure the amount of liquid in the sump and
determine whether the ALR has been exceeded. This is designed to verify both liner
integrity and leachate pump efficiency. If a leak exceeds the ALR, the
owner/operator must notify the Agency and respond in accordance with the
response action plan (§§264/265.223).
RESPONSE ACTIONS
There are also two different types of response actions for the design and
performance of the unit. The response action for the performance of the unit is
determined by the terms of the response action plan, triggered when the ALR has
been exceeded (§§264/265.223). If the action leakage rate has been exceeded, the
owner/operator must notify the Regional Administrator; determine what short-
term actions must be taken (e.g., shut down of the facility for repairs); determine the
location, size, and cause of any leak; and send the assessments to the Region.
There are also emergency repair provisions for unit design failure at permitted
facilities only (§264.227). If there is an indication of a failure of the containment
system (e.g., a sudden drop in the level of the contents not attributable to changes in
the flow in or out of the impoundment), the surface impoundment must be
removed from service. When this occurs, the owner/operator must follow the
procedures in the contingency plan, including any necessary emergency repairs.
CLOSURE
Closure of a hazardous waste surface impoundment can take one of two forms. The
first option, called clean closure, requires for the owner/operator to remove or
decontaminate all wastes and unit components at closure (§§264/265.228(a)(l)). If
the unit cannot be clean-closed, then the owner/operator must employ the second
alternative. Under this approach, wastes are left in place and stabilized, free liquids
are removed, and a cap or cover is placed on top of the waste. Since surface
impoundments are generally used for storage, the second option is equivalent to
closing as a landfill (which is always a final resting place of hazardous wastes) and
also requires the operator to take certain precautions for a set time period after
closure (known as post-closure care (§§264/265.228(a)(2) and (b)).
REGULATIONS FOR SPECIAL WASTES
The regulations place special requirements on surface impoundments that handle
ignitable or reactive wastes because these wastes require continuing protection from
conditions that could cause them to ignite or react (§§264/265.229).
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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6 - Land Disposal Units
Additionally, §§264/265.230 prohibit the placement of incompatible waste or
materials, as described in Appendix V of Parts 264/265, in the same surface
impoundment unless certain precautions are taken.
Further, if an owner/operator of a surface impoundment plans to manage dioxin-
containing waste (F020, F021, F022, F023, F026, and F027), they must employ a special
management plan approved by the Regional Administrator (§264.231). These wastes
can only be disposed of in a permitted surface impoundment.
SURFACE IMPOUNDMENT RETROFITTING
Owners and operators of existing surface impoundments that become subject to
RCRA as the result of a new hazardous waste listing or characteristic must retrofit or
cease receipt of hazardous waste and begin the closure process within four years of
the promulgation of the listing or characteristic. For example, owners and operators
of surface impoundments which became subject to RCRA as the result of the
promulgation of the Toxicity Characteristic waste codes on March 29,1990, were
.required to retrofit those units to meet the minimum technology requirements or
cease receipt of hazardous waste and begin the closure process by March 29,1994 (55
F£ 11798; March 29,1990).
SURFACE IMPOUNDMENT VS. TANK
The definitions of surface impoundment and tank are very similar and tend to
create confusion. The major difference in the two definitions is what provides the
structural support to the unit. Surface impoundments are supported by earthen
materials while tanks are supported by non-earthen materials (e.g., wood, concrete,
steel, plastic). In determining whether a unit is supported by earthen or non-
earthen material, it should be evaluated as if it were free-standing and filled to its
design capacity. If the unit can maintain its structural integrity it is considered a
tank. If the unit cannot retain its structural integrity, it is considered a surface
impoundment.
2.2 WASTE PILES
Regulations governing the management of hazardous waste in waste piles are
found in Parts 264/265, Subpart L. Waste piles, which are essentially non-
containerized piles of solid, nonflowing hazardous waste, are temporary units, for
storage or treatment only (§260.10). Because waste piles are temporary units, not
intended for final disposal of wastes, Subpart L does not contain post-closure care
regulations for waste piles that are closed with waste in place; such units are
considered permanent or disposal units, and are subject to post-closure regulation as
landfills (see Section 2.4).
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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Land Disposal Units - 7
Owners/operators of permitted waste piles that meet special requirements are
subject to reduced regulation. Specifically, the waste pile must be located inside or
under a structure and not receive free liquid, protected from surface water run-on,
designed and operated to control dispersal of waste, and managed to prevent the
generation of leachate. If these standards are met, the owner/opera tor of the
permitted waste pile is exempt from groundwater monitoring requirements as well
as the design and operation requirements for waste piles (§264,250(c)),
DESIGN AND OPERATION
Waste piles are subject to nearly the same MTRs as surface impoundments.
Specifically, new units, lateral expansions, and replacement units require a double
liner and LCRS (§§264.251 (c) and 265.254). In addition, waste piles, with certain
exceptions, require a second leachate collection and removal system above the top
liner. If the permitted waste pile is not subject to MTR (i.e., a unit, lateral expansion,
or replacement for which construction commenced before July 29, 1992), then the
unit is subject to a single liner and basic LCRS requirements. Interim status waste
piles that are not subject to MTR are subject only to liner, run-on, and run-off
controls if leachate or run-off is found to be a hazardous waste.
Permitted waste piles are subject to stormwater run-on and run-off controls to
minimize leachate generation during storms (§§264.251 (g),(h), and (i)). These
requirements are designed to keep stormwater from contacting the hazardous
wastes and to keep any contaminated stormwater from being released into the
environment. Owners/operators of waste piles must also cover or manage their
wastes to prevent any wind dispersal. Interim status waste piles are not subject to
the stormwater controls, but are subject to wind dispersal provisions (§265.251).
INSPECTION AND RELEASE RESPONSE
Waste piles are subject to the same inspection and release response requirements as
surface impoundments. Specifically, waste piles are required to establish an ALR
(§§264.252 and 265.255), a response action plan (§§264.253 and 265.259), monitoring
and inspection schedule (§264.254), and a CQA plan (§§264/265.19). The interim
status monitoring and inspection provision only requires the owner/operator of a
waste pile meeting MTR to record the amount of liquids removed from the leak
detection system sump at least once a week (§265.260). Note that waste piles are not
subject to the emergency repair provisions for surface impoundments.
CLOSURE
Since waste piles are storage units, as opposed to disposal units, all waste residues
and contaminated subsoils and equipment must be removed or decontaminated at
closure (§§264/265.258(a)). This requirement is identical to clean closure of a surface
impoundment. If the owner or operator removes or decontaminates all waste
residues and makes all reasonable efforts to remove or decontaminate all structures
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for. Hotline training purposes.
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8 - Land Disposal Units
and soils and finds that some contamination remains, the waste pile will then be
subject to the closure requirements for landfills, including post-closure care
(§§264/265.258(b)).
SPECIAL REQUIREMENTS FOR CERTAIN WASTES
Waste piles are subject to the same specialized standards for ignitable, reactive,
incompatible, and dioxin-contairting waste as surface impoundments. These
requirements are discussed in Section 2.1.
WASTE PILE VS. CONTAINMENT BUILDING
Containment buildings, sometimes characterized as "indoor waste piles," are units
used to hold uneontainerized piles of hazardous waste. The difference between
waste piles and containment buildings, from a regulatory standpoint, is that
containment buildings are not land disposal units. For this reason, containment
buildings are designed with a containment system rather than a liner and leak
detection system (Parts 264/265, Subpart DD). The module entitled Containment
Buildings provides more information about the standards that apply to
containment buildings.
2.3 LANDFILLS
Since landfills are used as final disposal sites for a large portion of the nation's
hazardous waste, it is critical that they are monitored during the entire active life
(which includes closure) and the post-closure period. The regulations concerning
hazardous waste landfills are promulgated as Subpart N of Parts 264/265.
DESIGN AND OPERATION
Landfills are subject to virtually the same MTRs as surface impoundments and
waste piles. They must have a double-liner, LCRSs, leak detection (§§264/265.301),
and an ALR (§§264/265.302). Like waste piles, landfills require the second LCRS
above the top liner. In addition, landfills must have stormwater run-on and run-off
controls to prevent migration of hazardous constituents for at least a 25-year storm,
and a cover to prevent wind dispersal.
INSPECTION AND RESPONSE ACTIONS
Once again, the inspection and response action plans are almost identical to the
requirements for surface impoundments, including a response action plan if the
ALR is exceeded (§§264.304 and 265.303), and a CQA program (§§264/265.19). In
addition, the owner/operator of a hazardous waste landfill must perform
monitoring and inspections (§§264.303 and 265.304). As with surface
impoundments and waste piles, these requirements ensure that the unit is
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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Land Disposal Units - 9
maintained in good working condition and that any problems are promptly
detected.
CLOSURE
Since landfills typically serve as permanent disposal sites, the closure and post-
closure requirements for landfills are somewhat different from those for other land-
based units. One example is the requirement for a final cover over the landfill that
can provide long-term minimization of liquid migration through the closed
landfill, promote drainage, accommodate settling, and function with a minimum
amount of maintenance (§§264/265.310(a)). After closure, the owner or operator
must comply with the post-closure requirements of §§264/265.117 through
264/265.120 covering such actions as monitoring and maintenance (see the module
entitled Closure/Post-Closure). In addition, the owner/opera tor must maintain the
final cover, leak detection system, and groundwater monitoring system, as well as
prevent run-on and run-off from damaging the final cover, and protect the
surveyed benchmarks (i.e., location and characteristics) of the landfill.
SPECIAL REQUIREMENTS FOR CERTAIN WASTES
Like surface impoundments and waste piles, landfills are subject to certain
restrictions on the management of ignitable, reactive, incompatible, and dioxin-
containing wastes. Unlike other units, though, the placement of bulk or
noncontainerized liquid hazardous waste or hazardous waste containing free liquids
in any landfill is prohibited (§§264/265.314(b)). The placement of nonhazardous
liquids in a landfill is also essentially prohibited (§§264.314(e) and 265.314(f)). There
are only certain situations when containers holding free liquids can be placed in a
landfill (e.g., small containers such as ampules, containers that are products such as
batteries, or lab packs) (§§264.314(d) and 265.314(c)). If sorbents are used to treat
hazardous wastes so that the waste no longer contains free liquids, the
owner/operator must use nonbiodegradable sorbents.
SPECIAL REQUIREMENTS FOR CERTAIN CONTAINERS
To prevent significant voids that could cause collapse of final covers when
containers erode, and to maintain and extend available capacity in hazardous waste
landfills, containers placed in a landfill must be either at least 90 percent full or
crushed, shredded, or in some other way reduced in volume, unless they are very
small, such as ampules (§264.315).
Finally, there are special standards for lab packs or overpacked drums being placed
in a landfill (§§264./265.316). Lab packs generally contain small containers of a wide
variety of hazardous wastes in relatively small volumes that are packed in sorbent
material to prevent leaking. This sorbent material must be nonbiodegradable.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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10 - Land Disposal Units
2.4 LAND TREATMENT UNITS
While surface impoundments, waste piles, and landfills share many regulatory
standards, land treatment units (LTUs) are significantly different both in purpose
and in management. Land treatment involves the application of waste on the soil
surface or the incorporation of waste into the upper layers of the soil in order to
degrade, transform, or immobilize hazardous constituents present in hazardous
waste. Essentially, the waste is treated within the matrix of the surface soil, whereas
the major goal of the other units is to prevent migration to the surface soil.
Specifically, the waste must be placed only in the unsaturated zone, which is the
portion of the surface soil above the water table (or the highest point of the
groundwater flow). Based on the proximity to the groundwater, the success of land
treatment is highly dependent on the operational management of the unit.
Because the goal of land treatment is to let the soil microbes and sunlight degrade
the hazardous waste, the design and operating standards are significantly different
from those imposed on the three types of units already covered. Land treatment
units generally do not use impermeable liners to contain wastes. Instead, units rely
on the physical, chemical, and biological processes occurring in the top soil layers.
In a sense, these units can be viewed as an open system.
Maintenance of proper soil pH, careful management of waste application rate, and
control of surface water run-off are all key to the operation of a land treatment unit.
The regulations concerning hazardous waste land treatment units are promulgated
in Subpart M of Parts 264/265.
Because placement of hazardous waste in a land treatment unit is considered land
disposal, LDR standards must be considered. If the hazardous waste does not meet
the applicable treatment standard prior to placement in the land treatment unit, the
unit owner or operator must obtain a no-migration variance before applying any
hazardous waste to the unit. (See the module entitled Land Disposal Restrictions
module for more details concerning the LDR standards and no-migration
variances.)
DESIGN AND OPERATION
Land treatment units must devise a program and demonstrate its effectiveness
given the design of the unit and characteristics of the area. In addition, the
regulations set out specific operating requirements that must be met in the
treatment program. The following discussion details these requirements.
Treatment Program and Demonstration
The requirements outlined in the treatment program, including design and
operating criteria and unsaturated zone monitoring, stem from a treatment
demonstration. The purpose of the treatment demonstration is to show that
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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Land Disposal Units -11
hazardous constituents in the waste can be completely degraded or immobilized in
the treatment unit. A treatment demonstration may involve field testing on a
sample soil plot or laboratory testing. The Regional Administrator uses
information provided by the treatment demonstration to set permit standards.
Interim status units are not required to establish a treatment program because the
interim status regulations are self-implementing. Owners/operators can only place
hazardous waste in the LTU, however, if the waste will be rendered nonhazardous
or less hazardous (§265.272(a)).
During the treatment demonstration, the owner/opera tor must establish the
following parameters:
• Specify the wastes that may be handled at the unit. In general, land treatment
is confined to wastes that are primarily organic and that can be greatly reduced
in volume by physical, chemical, and biological decomposition in surface
soils. The owner/operator must be able to account for smaller fractions of
heavy metals and persistent organic compounds by immobilizing those
constituents.
• Formulate a set of operating measures. The LTU must be operated in a
manner that will maximize degradation, transformation, and immobilization
of hazardous waste constituents. The specifics of the operation are discussed
in the following section of this module.
* Establish unsaturated zone monitoring. The purpose of this program is to
make sure that treatment is occurring within the treatment zone, and that all
hazardous constituents are being adequately treated. The information
provided from the monitoring can help the owner/opera tor "fine tune" the
treatment process to maximize the success of the treatment. Unsaturated
zone monitoring involves soil monitoring (e.g., obtaining soil samples)
immediately below the treatment zone.
» Define the treatment zone. This zone comprises the horizontal and vertical
dimensions of the unsaturated zone in which the owner/opera tor intends to
perform the actual treatment. The zone can be no deeper than 1.5 meters (5
feet) and the bottom of the zone must be at least one meter (3.2 feet) from the
seasonal high water table.
Operation
Basic design and operating requirements are outlined in §§264.273 and 265.272.
These sections require the Regional Administrator to specify certain parameters in
the facility permit:
• Rate and method of waste application
« Measures to control soil pH
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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12 - Land Disposal Units
• Measures to enhance microbial and chemical reactions
« Measures to control the moisture content of the treatment zone.
In addition, land treatment units are subject to requirements for stormwater run-on
and run-off controls. Management to control wind dispersal and weekly inspections
is also required.
Food Chain Crops
In some cases, an owner/operator may grow food-chain crops on a land treatment
unit (§§264/265.276). The Agency believes that this can be done safely if certain
conditions are met that require the owner or operator to demonstrate that
hazardous constituents are not present in the crop in abnormally high
concentrations. Additionally, if cadmium is present in the unit, the owner/operator
must comply with additional management standards specified under
§§264/265.276(b).
INSPECTIONS AND RESPONSE ACTIONS
Although there are no requirements to inspect the unit, the owner/opera tor must
maintain unsarurated zone monitoring to assure that the unit is meeting its
performance standards (§§264/265.278).
As discussed earlier, the purpose of unsaturated zone monitoring is to provide
feedback on the success of treatment in the treatment zone and to determine if
hazardous constituents are migrating out of the treatment zone (i.e., the monitoring
program must be designed to determine the presence of hazardous constituents
below the treatment zone). Generally this means that the owner/operator would
monitor for the most stable hazardous constituents found in the wastes placed in or
on the treatment zone. Keep in mind that unsaturated zone monitoring is not a
substitute for groundwater monitoring. Both are required for land treatment units.
To perform unsaturated zone monitoring, the owner/operator must first establish
which constituents must be monitored and the background levels of those
constituents in the soil. The frequency of the monitoring is based on the elements
of the operation of the LTU, such as the frequency, timing, and rate of application of
the waste. Once the samples have been taken, the owner/operator must determine
whether there is a statistically significant change over the background values (i.e.,
the natural constituent levels in the soil) for any hazardous constituent. If there is a
statistically significant increase in the hazardous constituents of concern, the
owner/opera tor must notify the Regional Administrator within seven days, and
submit a permit modification within 90 days to change the operating practices at the
facility to sufficiently treat hazardous constituents within the treatment zone.
The information in this document is not by any means a complete representation of EPA's regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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Land Disposal Units -13
CLOSURE
When a land treatment unit is being closed, the owner/operator maintains all
operating parameters to continue the treatment processes, and continues run-on
and run-off controls and unsaturated zone monitoring. The major element of the
closure procedure is placing a vegetative cover over the closing unit that is capable
of maintaining growth without extensive maintenance. At completion of closure
the owner or operator may submit the closure certification by an independent
qualified soil scientist in lieu of an independent registered professional engineer.
Closure and post-closure are waived if the hazardous constituents in the treatment
zone no longer exceed background levels.
SPECIAL REQUIREMENTS FOR CERTAIN WASTES
Like other LDUs, land treatment units are subject to limitations regarding ignitable,
reactive, incompatible, and dioxin-containing wastes (§§264/265.281-.283).
The information in this document is not by any means a complete representation of EPA s regulations or policies,
but is an introduction to the topic used for Hotline training purposes.
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