EPA
United States
Environmental Protection
Agency
Office of
Solid Waste and
Emergency Response
Directive No. 9355.0-661
EPA540/F-96/017
PB 96-963313
January 1997
Landfill Presumptive Remedy
Saves Time and Cost
Office of Emergency and Remedial Response (5202G)
Intermittent Bulletin
Volume 1 Number 1
Since Superfund's inception in 1980, the removal and remedial programs have found that certain categories of sites have similar characteristics,
such as types of contaminants present, past industrial use, or environmental media affected. Based on a wealth of information acquired from
evaluating and cleaning up these sites, Superfund undertook the presumptive remedy initiative to develop remedies that are appropriate for
specific site types and/or contaminants. One site category for which EPA developed a presumptive remedy is municipal landfills. This bulletin
summarizes the results of implementing the containment presumptive remedy at three CERCL A municipal landfill sites. At each of the sites,
both time and costs were saved in conducting the RI/FS. When compared to similar "control" sites, EPA estimates time savings ranging from
36 to 56 percent, and cost savings up to 60 percent. In addition to demonstrating significant time and cost savings, the pilots also indicate that
municipal landfill sites are good candidate sites for implementing the presumptive remedy as an early action, such as a non-time-critical
removal. The combination of this presumptive remedy with an early action resulted in significant savings at one pilot site.
Introduction
EPA expects that the use of presumptive remedies will streamline
removal actions, site studies, and cleanup actions while improving
consistency, reducing costs, and increasing the speed with which
hazardous waste sites are remediated. EPA has developed several
presumptive remedies to date; a list of presumptive remedy
directives is provided at the end of this document. The results of
implementing the containment presumptive remedy at three
CERCLA municipal landfill sites are discussed in this bulletin.
The Containment Presumptive Remedy
EPA established containment as the presumptive remedy for
municipal landfills in September 1993. The containment
presumptive remedy includes the following components, as
appropriate on a site-specific basis:
• Landfill cap;
• Source area ground-water control to contain plume;
• Leachate collection and treatment;
• Landfill gas collection and treatment;
• Institutional controls to supplement engineering controls.
The presumptive remedy does not address exposure pathways
outside the source area (landfill), nor does it include long-term
ground-water response actions.
The Pilot Sites
Prior to establishing the presumptive remedy, EPA initiated a pilot
project at three sites to assess the effectiveness of the containment
remedy in streamlining the remedial investigation/feasibility study
(RI/F S) process for municipal landfills. The pilots implemented
the streamlining principles outlined in the document, "Conducting
Remedial Investigations/Feasibility Studies for CERCLA
Municipal Landfill Sites," February 1991, Directive No.
EPA/540/P-91001 (hereafter referred to as the "1991 MLF RI/FS
guidance"). This 1991 MLF RI/FS guidance provides the
implementation framework of the containment presumptive
remedy.
EPA found the containment remedy to be a very effective tool for
streamlining the RI/FS at municipal landfills. This bulletin
describes the pilot sites, the ways in which each RI/FS was
streamlined, and the time and cost savings realized at each of the
sites. See Attachment A at the end of this bulletin for brief site
summaries.
Who Can Use The Presumptive Remedy?
If you are the manager of a municipal landfill site, it is likely that the presumptive remedy can help you save time and money on
the RI/FS at your site. Although the presumptive remedy is most beneficial when incorporated at the scoping stage of the RI/FS, if
your site has progressed beyond that point, you may still be able to streamline your site characterization sampling strategy, baseline risk
assessment, and/or feasibility study.
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EPA piloted the containment remedy at the following municipal
landfills beginning in the Spring of 1992:
• Albion-Sheridan Township Landfill, Michigan
• Lexington County Landfill, South Carolina
• BFI/Rockingham Landfill, Vermont
These sites were selected as pilots because they were in the
scoping phase of the RI/FS at the time. The biggest savings in time
and cost can be realized if streamlining is incorporated at the very
beginning of the scoping phase of the RI/FS. All of these sites now
have signed Records of Decision (RODs), with containment
selected as part of the remedy at each of the sites.
EPA evaluated the impact of the containment remedy as a
streamlining tool at the three pilot sites by estimating time and cost
savings. The sites were evaluated in a paired analysis, comparing
the pilot sites to the three "control" sites listed in Highlight 1.
Remedy selection at the control sites was based on the results of
conventional RI/FSs.
The factors considered in selecting the "control" sites included
(listed in order of priority): (1) the state in which the landfill is
located since State closure requirements often affect aspects of
remedy selection; (2) the lead for the site (e.g., Fund-lead); and (3)
the size of the landfill (in acres). Summary information on the pilot
and control sites is provided in Highlight 1.
Highlight 1
Pilot/Control Site Characteristics
PILOT SITES
Name
Albion-
Sheridan
BFI
Lexington
Co.
State
Ml
VT
SC
Lead
F
PRP
PRP
Size
30
19
70
CORRESPONDING CONTROL SITES
Name
V\fest
KL
Parker
Cedar-
town
LF
State
Ml
VT
GA
Lead
F
PRP
PRP
Size
87
19
6.8
Pilot Results
Two areas of the RI/FS process presented the greatest opportunity
for streamlining at the pilot sites: 1) a phased approach to site
characterization, and 2) streamlining the risk assessment.
Phased Approach to Site Characterization
The containment presumptive remedy emphasizes the use of
existing data to the degree possible, and discourages
characterization of landfill contents since it is presumed that the
landfill will be contained, unless information is available indicating
the need to investigate and potentially remove or treat hot spots. In
keeping with these principles, a phased approach to sampling is
recommended.
The phased approach to site characterization is a site-specific
strategy that frames the data collection effort within the context of
determining whether a risk is present at a site rather than
characterizing the nature and extent of all contamination in a
landfill.1 A site-specific determination is made as to the
environmental medium most likely to present a risk based upon any
existing data available, and sampling of that pathway is conducted
first.
At many landfill sites, ground-water contamination is likely to
present a significant risk, and thus trigger the need for action.2 At
the pilot sites, ground water was the first medium sampled, and at
each of the pilot sites, ground-water contamination supported the
need for a response action. In two cases, soil sampling of the
landfill source area was never conducted; sampling was limited to
determining risk from the ground water. At one site, the State
conducted additional sampling of the landfill area.
If ground-water data had not clearly demonstrated a risk at the pilot
sites, additional sampling would have been conducted (in
sequence) to determine whether a risk was present from other
media or exposure pathways, such as contaminated soil and/or
landfill gas. At the pilot sites, additional sampling was not
necessary to determine risk, and since containment of the landfill
was presumed, sampling and analysis was not required for the
purpose of site characterization.
Streamlined Risk Assessment
For many landfill sites, it will be possible to streamline the risk
assessment portion of the RI/FS. This is possible because the
containment remedy addresses all migration pathways presented by
the landfill source. The basis of the streamlined risk assessment
process to be employed at MLFs is the conceptual site model
(discussed in Section 2.5 of the 1991 RI/FS MLF guidance), which
is used to identify all exposure pathways associated with the landfill
source (i.e., direct contact with soil, exposure to contaminated
ground water, contaminated
'This phased approach applies to the landfill source only.
Contamination that has migrated away from the landfill source
must be characterized, and the associated risk estimated.
2See OSWER Directive 9355.0-30, "Role of the Baseline Risk
Assessment in Superfund Remedy Selection Decisions," April 22,
1991, which states that if MCLs or non-zero MCLGs are exceeded,
[a response] action generally is warranted.
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leachate, and/or landfill gas). The exposure pathways are then
compared to those addressed by the containment remedy, as
follows:
• direct contact with soil and/or debris prevented by landfill cap;
• exposure to contaminated ground water prevented by ground-
water control;
• exposure to contaminated leachate prevented by leachate
collection and treatment; and
• exposure to landfill gas addressed by gas collection and
treatment, as appropriate.
This comparison reveals that the containment remedy addresses all
pathways associated with the landfill source. The phased approach
can be implemented at landfill sites using the conceptual site model
because it demonstrates that all exposure pathways are addressed
by the containment remedy, and field sampling is therefore not
required to characterize the nature and extent of contamination
once it has been demonstrated that the site presents a risk and
warrants action.
A streamlined risk evaluation was successfully conducted at the
three pilot sites, with contaminated ground water presenting the
justification for a response action. Sampling, analysis, and a
conventional risk assessment were required to characterize
contamination, if any, that had migrated away from the source
areas.
Quantitative Results
As illustrated in Highlight 2, the RI/FS durations for the pilot sites
ranged from 23 to 32 months, compared to 44 to 72 months for the
control sites. The average pilot RI/FS duration was 28 months, as
compared to the national average of 51 months. The RI/FS
durations for the pilot sites represent a time savings ranging from
16 to 40 months when compared to the control sites, and 23
months when compared to the national average. These results
translate into an estimated time savings ranging from 36-56 percent
when comparing the pilots to the control sites, and an estimated 45
percent when comparing the average pilot duration to the national
average.
The figures for the BFI/Rockingham site include completion of an
Engineering Evaluation/Cost Analysis (EE/CA) to support
implementation of source control (i.e., cap, leachate and gas
collection) as a non-time-critical removal action. The EE/CA was
completed in 12 months, which is a subset of the 23 months
indicated in Highlight 2. The 23 months was the time required to
complete the RI/FS for the entire site, including ground-water
contamination.
The pilot results for the BFI/Rockingham site are particularly
noteworthy because the source control action was initiated just 12
months after the RI/FS start, and construction of the cap was
completed in July 1995, just three years after the RI/FS start.
A savings in time was also realized as a result of the streamlined
risk evaluations conducted at the pilot sites, as illustrated in
Highlight 3. The time required to complete the risk assessments at
the pilot sites ranged from 7 to 10 months, as compared to 9 to 22
months for the controls, which represents a savings ranging from
17 to 68 percent when compared to the control sites.
Highlight 2
RI/FS Durations (Months) for Pilot/Control Site
and National Averages
23
47
32
72
28
44
28
51
BFI Parker Albion- West Lexhg- Cedar- Pilot National
Sheridan KL ton Co. town Average Average
LF
Highlights
Risk Assessment Durations (Months) for
Pilot/Control Sites
22
10
Albion- West
Sheridan KL
Lexington Cedar-
Co- town
LF
Cost savings were estimated in one of two ways for the pilot sites.
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The RI/FS costs for Albion-Sheridan Landfill and Lexington
County were compared to the national average RI/FS cost of $1
million, resulting in an estimated 10 percent and 1 percent savings,
respectively, for those sites. The cost savings estimate for the
BFI/Rockingham site was developed by the PRP, and was based
upon a comparison with their costs for RI/FSs conducted at other
similar sites. A savings of 60 percent was estimated for the RI/FS,
which included the source area and areas of migration, and an
engineering evaluation/cost analysis (EE/CA) to support the non-
time-critical removal action on the landfill cap.
Conclusion
EPA found that the containment presumptive remedy resulted in a
savings of time and costs at each of the pilot sites. The savings
were the result of implementing a phased approach to site
characterization and streamlining the risk assessment, both of
which were possible because the landfill contents were contained.
The savings in time and costs were most significant at the
BFI/Rockingham site, where the cap was completed three years
after initiation of the RI/FS, and an estimated $3 million was saved.
This significant savings was the result of combining the
containment presumptive remedy with an early action
accomplished as a non-time-critical removal action. Based on
these results, municipal landfill sites appear to be well suited to the
combined application of these streamlining and acceleration tools.
Next Steps
Since establishment of the presumptive remedy, EPA has tracked
implementation at two additional landfill sites (demonstration
sites): (1) Bennington Landfill, Vermont, and (2) Tomah
Municipal Landfill, Wisconsin. EPA will summarize findings from
the demonstration sites upon signature of their respective Records
of Decision (RODs).
Presumptive Remedy Directives
To date, EPA has issued the following presumptive remedy
directives:
(1) "Presumptive Remedies: Policy and Procedures,"
September 1993, Directive No. 9355.0-47FS;
(2) "Conducting Remedial Investigations/Feasibilities Studies
for CERCLA Municipal Landfill Sites," EPA/540/P-
91/001, February 1991.
(3) "Presumptive Remedy for CERCLA Municipal Landfill
Sites," September 1993, Directive No. 9355.0-49FS;
(4) "CERCLA Landfill Caps RI/FS Data Collection Guide,"
August 1995, Directive No. 9355.3-18FS;
(5) "Site Characterization and Technology Selection for
Volatile Organic Compounds in Soil/Sludge," September
1993, Directive No. 9355.4-048FS;
(6) "Presumptive Remedies for Soils, Sediments, and
Sludges at Wood Treater Sites," December 1995,
Directive No. 9200.5-162.
(7) "Presumptive Response Strategy and Ex-Situ Treatment
Technologies for Contaminated Ground Water at
CERCLA Sites," EPA/540/R-96/023, October 1996.
In addition, presumptive remedies directives for the following types
of sites or contaminants are forthcoming:
(1) PCBs
(2) Manufactured gas plants
(3) Grain storage sites
(4) Metals in soils (in cooperation with the U.S. Department
of Energy).
Additional Information
For additional information on the pilot sites or the presumptive
remedy for municipal landfills, please call Andrea McLaughlin,
Office of Emergency and Remedial Response, 703-603-8793.
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Attachment A: Pilot Case Studies
Albion-Sheridan Landfill
Anecdotal evidence indicated that some quantity of
industrial wastes were disposed of at the 30-acre Albion-
Sheridan Landfill, but the location, volume and identity of
wastes were unknown. No data were available for the site
at the beginning of the RI/FS. EPA implemented the
streamlining principles of the 1991 MLF RI/FS guidance,
and scoped a phased approach to characterization of the
Albion-Sheridan site with the goal of implementing the
containment remedy. The draft work plan was revised to
incorporate the phased investigation, focusing first on
ground-water contamination to establish whether there was
a basis for a response action.
Ground-water contamination did support the need for
action at the site, so it was not necessary to quantify
additional exposure pathways for this purpose. The
remainder of the risk assessment was streamlined by using
a conceptual site model to demonstrate that the other
potential pathways of concern (e.g. direct contact) would be
addressed by the components of the presumptive remedy
(e.g. landfill cap).
EPA conducted a geophysical survey of the site to identify
potential drum storage areas. Based on the results of the
geophysics, EPA concluded that while there were
anomalies in the results, there were no areas that appeared
to consist of large numbers of drummed waste, thereby
warranting further investigation. Because the State had
remaining concerns with EPA's approach to hot spots, the
State conducted its own geophysical survey and dug test
pits at 12 locations. At one location approximately 300-
400 drums were uncovered, and EPA reiterated its
agreement to send any drums of hazardous waste off-site
for disposal. Of the 300-400 drums, the number containing
hazardous waste is unknown at this time.
Lexington County Landfill
Ground-water data were available for this 70-acre landfill
prior to initiation of the RI, which indicated exceedences of
MCLs, and therefore a basis for a response action. The
strategy for the Lexington County Landfill RI was similar
to the Albion-Sheridan Landfill, in that a phased approach
was implemented. Sampling focused on further
characterization of ground-water contamination, and the
risk assessment was streamlined, focusing also on the
ground-water pathway. Planned soil sampling and analysis
to estimate direct contact threats was eliminated, and it was
demonstrated (using a conceptual site model) that other
potential pathways of concern would be addressed by
components of the presumptive remedy.
A planned drum search of the 70-acre landfill was
eliminated based on the guidelines for hot spot
characterization contained in the 1991 MLF RI/FS
guidance. At Lexington County Landfill, as at Albion
Sheridan Landfill, it is likely that some industrial waste was
disposed of at the site, but the location, quantity and identity
of the wastes were unknown. Because there was no
evidence to guide such a search, EPA decided that the best
approach was to contain the landfill, accounting for
uncertainties in the nature of the wastes during the design.
The selected remedy includes consolidation and capping of
the waste areas, landfill gas collection and venting;
extraction of contaminated groundwater/leachate with
discharge to POTW; additional sampling of surface water
and sediment to characterize any off-site contamination;
and monitoring of ground water, surface water, sediment
and landfill gas. Additionally, to address a plume, a
ground-water pump and treat remedy was put in place.
BFI/Rockingham
Extensive ground-water data were available for this site at
the initiation of the RI, and the first step in implementation
of the presumptive remedy was to evaluate the potential for
using the data. The data were found to be useable to
establish an initial basis for action, which allowed
streamlining of the risk assessment and RI. Only
confirmational ground-water sampling was conducted
during the RI; characterization of the landfill surface soil
and debris mass did not occur. Geotechnical information
regarding settlement, cover quality, and stability was also
collected. The knowledge that containment was the likely
remedy allowed the RI to become primarily a design-
related investigation. In addition, based on historical
information, hot spots were not of concern at this site.
Levels of volatile organic compounds (VOCs) and certain
metals clearly indicated that a ground-water risk was
present. The existence of ground-water risk confirmed that
a "No Action" decision was unlikely, and that a landfill cap
would be a component of the source control action. The
risk assessment was streamlined by quantifying the ground-
water risk and qualitatively discussing the other pathways
that would be addressed by the source control action. All
pathways outside the landfill, which included off-site
ground water and off-site soils, were fully quantified. An
early action was conducted as a non-time-critical removal
at this site in order to begin construction of the landfill cap.
The combination of the presumptive remedy with the early
action resulted in a significant time savings in the remedy
selection and construction processes.
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