PB97-963129
EPA/541/R-97/086
July 1998
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Volney Municipal Landfill
Town of Volney, NY
8/7/1997
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Explanation of Significant Differences
VOLNEY LANDFILL SITE
TOWN OF VOLNEY
Oswego County, New York
EPA
INTRODUCTION
In accordance with the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA)
Section 117(c) and Section 300.435(c)(2)(i) of the National
Oil and Hazardous Substances Contingency Plan, if after the
adoption of a final remedial action plan, there is a significant
change with respect from the final plan, an explanation of the
significant differences and the reasons such changes were
made must be published.
The 1987 Record of Decision (ROD) for the Volney Landfill
site called for, among other things, supplemental capping of
the landfill side slopes, installation of a more extensive
leachate collection system, installation of a slurry wall,
performance of treatability studies to determine if leachate
treatment/disposal should be on- or off-site, implementation
of the on- or off-site treatment/disposal alternative, .and long-
term monitoring.
Following a re-sampling of the site in 1988, EPA issued a
Post-Decision Document (PDD) in 1989. This document
called for a re-evaluation of the slurry wall and .a
determination as to whether the leachate should be
treated/disposed of on-or off-site. Pre-remedial design (pre-
RD) studies were conducted to address these issues, as well
as questions that arose concerning the hydrogeology at the
site and the finding that a Resource Conservation and
Recovery Act (RCRA)-listed hazardous waste sludge had
been disposed of at the landfill.
The pre-RD studies, which were recently completed,
-oncluded that utilizing intermittent ground-water extraction
ar.d treatment, on an as-needed-basis (after initial pumping),
in combination with the existing leachate collection system,
would be more appropriate than expanding .the existing
leachate collection system and continuously collecting large
volumes of relatively dilute leachate. The studies also
determined that a slurry wall is not cost-effective in
combination with intermittent ground-water extraction, and the
collected leachate should be treated off-site. Further, it was
determined that the RCRA regulations related to the
hazardous waste sludge which was deposed of at the landfill
should be waived.
This Explanation of Significant Differences (ESD) will become
part of the Administrative Record file for the site. The entire
Administrative Record for the site, which includes the
remedial investigation (Rl) report, feasibility study (FS) report,
ROD, PDD, and other relevant documents are available for
public review at the following location:
Fulton Public Library
160 South First Street
Fulton, NY 13069
Hours: 10:00 am - 5:00 pm (Monday, Friday, and Saturday)
10:00 am - 8:00 pm (Tuesday - Thursday)
The Administrative Record file and other relevant reports and
documents are also available for public review at the EPA
Region II office at the following location:
U.S. Environmental Protection Agency
290 Broadway, 18m floor
New York, New York 10007
Hours: 9:00 am - 5:00 pm (Monday - Friday)
The change to the selected remedy is not considered by EPA
and the New York State Department of Environmental
Conservation (NYSDEC).to have fundamentally altered the
remedy selected in the ROD. The remedy remains protective
of human health and the environment and complies with
federal and state requirements that were identified in the
ROD.
SUMMARY OF SITE HISTORY, CONTAMINATION
PROBLEMS, AND SELECTED REMEDY
The 85-acre Volney Landfill, presently owned by Oswego
County, is located in a rural area of the Town of Volney. New
York. Landfilling operations were conducted in a 55-acre
unlined disposal area from 1969 to 1983. (The landfill has
been inactive since 1983.) Most of the waste materials
disposed of at the landfill consisted of residential.
commercial, institutional, and fight industrial wastes; however.
approximately 8.000 drums from Pollution Abatement
Services, a hazardous waste incineration facility located in
Oswego. New York, were approved for disposal at the landfill
by NYSDEC. While the approval applied only to discarded
drums containing known and limited chemical residues, it was
later reported that approximately 50 to 200 of these drums
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contained liquid waste of unknown volume and composition.
The physical condition and locations of these drums in the
landfill are unknown.
In March 1979, NYSDEC entered into a consent order with
the current owner of the landfill, Oswego County, after
ground-water quality standards were contravened in
monitoring wells near the site. The consent order required
ground-water monitoring, leachate disposal evaluation, and
the development of a landfill closure plan. Measures to close
the landfill, which included capping the landfill top with a liner
and soil, capping the side slopes with compacted soil,
installing a gas collection system, and installing a leachate
collection system, were undertaken between 1979 and 1985.
Off-site leachate disposal and ground-water monitoring have
been performed since the completion of the closure activities.
In October 1984, the Volney Landfill site was included on the
Superfund National Priorities List
A source control Rl/FS was conducted from 1985 to 1987 by
NYSDEC, and a ROD was signed by EPA on July 31.1987.
The selected remedy included, among other things,
supplemental capping of the landfill side slopes, installation
of a more extensive leachate collection system, installation of
a soil-bentonite slurry wall, treatment of the collected
leachate, treatabiiity studies to evaluate whether the leachate
should be treated on- or off-site, implementation of the on- or
off-site treatment/disposal alternative and long-term
monitoring.
After the signing of the ROD, it was learned that a quality
assurance/quality control review of the analytical data
associated with the Rl had not been performed. EPA re-
sampled the site in 1988 and, based upon the sample results,
concluded that hazardous substances were present in the
ground water, surface water, sediments, and leachate. On
September 29,1989, EPA issued the PDD, which reaffirmed
the remedy selected in the ROD. In response to comments
received during the public comment period, the PDD also
called for a re-evaluation of the cost-effectiveness of the
slurry wall called for in the ROD and a concurrent decision
concerning on- or off-site leachate treatment Studies
conducted from 1989 to 1990 provided information about off-
site leachate disposal and updated the construction costs for
the site remedy. The studies concluded, however, that before
any final decisions related to the slurry wall or leachate
treatment could be made, additional testing was needed to
resolve several critical issues concerning the site
hydrogeology (Le., possible artesian conditions, ground water
flow issues, and no reduction in leachate collection volume
since the 1985 capping of the landfill).
The decision related to selecting a method for leachate
treatment and disposal was further complicated by a
subsequent EPA finding that a RCRA-listed F019 waste
sludge had been disposed of in the landfill by the Miller Brew-
ing Co. (Miller) from 1976 to 1978'. RCRA would require that
wastes which were derived from RCRA-listed waste
(including leachate which had been in contact with listed
waste) would also have to be treated as a RCRA-listedj
hazardous waste, irrespective of the level of hazardous
constituents in the leachate. In September 1991, Miller
requested that EPA reconsider the RCRA-F019 classification
for its sludges that were disposed of in the landfill.
EPA concluded that additional data gathering at the site was
necessary to resolve the issues concerning the site
hydrogeology and to address the F019 RCRA-listed waste
issue, which could significantly affect future leachate disposal
requirements and costs.
An Administrative Order on Consent was signed in June 1993
for the performance of a pre-RD study by a group of
Potentially Responsible Parties.
The data gathering related to the pre-RD study was
conducted from 1994 to 1996, resulting in the completion of
a Design Data Evaluation Report in June 1997. The Design
Data Evaluation Report presented several new findings
related to the hydrogeology and the nature of contamination
at the site:
• the ground water at the perimeter of the site is
characterized by intermittent increases in contaminant
concentrations, with no consistent or definable
contaminant plume leaving the perimeter of the landfill,
while the leachate is somewhat dilute compared to
leachate from other, younger, landfills;
•
• approximately 50% more leachate (\.e.. 6.77 million
gallons per year) is generated from the site than was
reported in the Rl;
• a sand and gravel unit (instead of the low permeability
lodgement till reported in the Rl) was found in the
southeast area of the site, which would necessitate
doubling the leachate collection system piping to 7,600
feet;
• the Volney Landfill occupies a topographical high, which
makes the site optimally suited for achieving maximum
reductions in leachate through capping and through
surface water controls;
• a protective separation is present between the bottom of
the landfilled waste and the water table (eliminating the
waste as a direct source of ground-water contamination
once the landfill is capped); and
'in November 1980, the wastes from the coating of aluminum cans
(such as Miner's process) were regulated as a RCRA-Jisted
hazardous waste.
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natural attenuation appears to be occurring between the
landfill perimeter and downgradient residential wells,
thereby protecting these wells.
DESCRIPTION OF SIGNIFICANT DIFFERENCES AND THE
BASIS FOR THOSE DIFFERENCES
In an attempt to address the outstanding issues so as to
appropriately refine the remedy selected in the ROD. the
SPRDS developed and evaluated seventeen remedial
alternatives. The alternatives evaluation included
comparisons of different combinations of remedial
components (i.e.. leachate drains versus extraction wells,
slurry wall versus no slurry wall, on- versus off-site leachate
treatment/disposal, and hazardous versus nonhazardous
leachate treatmentfdsposal). All of the alternatives that were
evaluated utilized the same supplemental side slope cap.
Based upon this evaluation, it was concluded that
• utilizing intermittent ground-water extraction and
treatment, on an as-needed-basis (after initial pumping),
in combination with the existing leachate collection
system, would be more appropriate than expanding the
existing leachate collection system and continuously
collecting large volumes of relatively dilute leachate;
• a slurry wall is not cost-effective in combination with
intermittent ground-water extraction; and
• the collected leachate should be treated off-site.
Further, it was concluded that the RCRA regulations related
to the hazardous waste sludge which was disposed of at the
landfill should be waived. Summarized below is the basis for
these conclusions.
Since selecting an appropriate method of leachate treatment/
disposal would be significantly influenced by whether or not
the leachate would have to be handled as a RCRA-fisted
hazardous waste, the F019 issue is addressed first
F019 ISSUE - RCRA REGULATIONS WAIVER
As noted above, EPA determined that RCRA-listed F019
waste sludges had been disposed of in the landfill by Miller.
A review of analytical data related to five different batches of
leachate collected from the landfill from 1992 to 1996
(approximately 150,000 gallons/batch) did not however,
show either F019 constituent (hexavalent chromium or
cyanide). In addition, based upon information provided to
EPA by Miller in 1996, EPA has determined that one of the
two F019 hazardous waste constituents, cyanide, was
probably never used in the Miller plant process. EPA has
also concluded that the other constituent, hexavalent
chromium, would likely have been converted to trivalent
chromium by Miller's wastewater treatment process.
Therefore, trivalent chromium, not the more toxic hexavalent
chromium, would have been the primary chromium
component in the sludge delivered to the landfill from 1976
to 1978.
Based on these considerations, EPA determined that the
RCRA regulations applying to this matter should be "waived"
on the basis of "equivalent standard of performance"
pursuant to Section 121(d)(4)(D) of CERCLA, and
§300.430(f)(1)(iQ(C)(4) of the National Oil and Hazardous
Substances Pollution Contingency Plan. Use of this waiver is
intended where the standard of performance can be equaled
or exceeded through the use of another standard. Invoking
this waiver will also result in a mqre cost-effective remedy.
This waiver will not, however, relieve Oswego County from
continued responsibility pursuant to CERCLA to test the
leachate as a CERCLA waste and dispose of it as hazardous,
if the data so warrant
DESCRIPTION OF THE SIGNIFICANT DIFFERENCES
A review of ground-water data collected from monitoring
wells located at the perimeter of the landfill shows a relatively
low frequency of organic contamination, characterized by
intermittent increases Jn contaminant concentrations. In
addition, there is no definable contaminant plume at the
perimeter of the landfill. Further, pre-RD study data indicate
that natural attenuation is occurring in a sizable buffer zone
between the landfill perimeter and the downgradient
residential wells. In addition, natural attenuation appears to
have been protecting the residential wells for a significant
period of time. Based upon these findings, EPA has
concluded that it would be more appropriate to collect the
contaminated ground water On combination with the existing
leachate collection system), on an as-needed-basis (based
upon criteria established during the design phase), to match
the intermittent elevated contaminant concentrations, rather
than expanding the existing leachate collection system and
continuously collecting large volumes of relatively dilute
leachate.
EPA has also determined that the installation of a slurry wall
and leachate collection drain system to isolate and collect
leachate will not offer a significant protective benefit in
comparison to te cost, because once the landfill's side slopes
are capped, it is estimated that over 99% of the surface water
infiltration will be eliminated. For the same reason, leachate
collection by extraction wells which are pumped intermittently
would be more cost-effective than a leachate collection drain
system.
With respect fo leachate treatment and disposal, EPA has
concluded that off-site treatment and disposal of
nonhazardous leachate is more cost-effective than on-srte
treatment and disposal.
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DESCRIPTION OF MODIFIED REMEDY
The selected remedy, as modified by this ESD, includes
supplemental capping of the landfill side slopes, continued
leachate collection from the existing leachate collection
system, intermittent ground water extraction on an as-
needed-basis (after initial pumping), off-site leachate and
ground-water treatment, and long-term monitoring.
SUPPORT AGENCY COMMENTS
NYSDEC supports the modified remedy due to its
environmental, public health, and technical advantages over
the remedy selected in the 1987 ROD and 1989 POO.
AFFIRMATION OF STATUTORY DETERMINATIONS
Considering the pre-RD study information that has been
developed and the changes that have been made to the
selected remedy, EPA and NYSDEC believe that the modified
remedy remains protective of human health and the
environment, complies with federal and state requirements
that are applicable or relevant and appropriate to this
remedial action or provides justification for a waiver, and is
cost-effective. In addition, the modified remedy utilizes
permanent solutions and alternative treatment technologies
to the maximum extent practicable for this site.
EPA and NYSDEC also believe that the RCRA regulations
related to the hazardous waste sludge which was disposed of -
at the landfill should be waived.
PUBUC PARTICIPATION ACTIVITIES
EPA and NYSDEC rely on public input to ensure that the
concerns of the community are considered in selecting an
effective remedy for each Superfund site. To this end, this
ESD is being made available to the public for revjew and
comment Comments and questions should be directed to:
JackODell
Remedial Project Managt'
Central New York Remediation Section
U.S. Environmental Protection Agency
290 Broadway, 20m Floor
New York, New York 10007-1866
Telephone: (212)637-4256
Telefax: (212) 637-3966
lntemetOdell.Jack@epamail.epa.gov
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New York State Department of Environmental Conservation
50 Wolf Road, Albany, New York 12233-7010
John f. Ciha
Commissioner
Mr. Richard Caspe AUG I 2 I997
Director
Emergency and Remedial Response Division
United States Environmental
Protection Agency, Region II
290 Broadway
New York, New York 10007-1866
Dear Mr. Caspe:
RE: Site No. 7-38-003
Volney Landfill Site
Volney, Oswego County
The New York State Departments of Environmental Conservation and Health
have reviewed the August 1997 Explanation of Significant Differences (ESD). The ESD
calls for collection and treatment of contaminated groundwater on an as needed basis and
addresses the F019 issue. The Health Department, in its July 24 concurrence letter (copy
enclosed), has raised a concern regarding the potential off-site migration of contaminated
groundwater and a need to implement measures to prevent off-site migration. It is my
understanding that this issue will be addressed during the remedial design phase.
The State concurs with the content of the ESD and recommends that it be
approved.
Sincerely,
Michael J. OToole, Jr.
Director
Division of Environmental Remediation
Enclosure
cc: G. A. Carlson - NYSDOH
M.McCabe-NYSDOH
J. OTtell - USEPA, Region E
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION II
-5 l997
SUBJECT: Explanation of Significant Differences forthe Volney Landfill Superfund Site
FROM: Richard L. Caspe, P.E., Director /^—
Emergency and Remedial Response^)ivision
TO: Jeanne M. Fox
Regional Administrator
Attached is an Explanation of Significant Differences (ESD) for the Volney Landfill Superfund site.
This ESD modifies the previously-selected remedy, which consists of supplemental capping of the
landfill side slopes, installation of a more extensive leachate collection system, installation of a slurry
wall, performance of treatability studies to determine if leachate treatment/disposal should be on- or
off-site, implementation of the on- or off-site treatment/disposal alternative, and long-term
monitoring.
Based upon the results of pre-design studies, we propose to modify the remedy to include
supplemental capping of the landfill side slopes, continued leachate collection from the existing
leachate collection system, intermittent ground water extraction on an as-needed-basis (after initial
pumping), off-site leachate and ground-water treatment, and long-term monitoring.
Please indicate your approval of the modified site remedy by signing below.
If you have any questions related to the ESD, please call me at extension 4390.
Attachment
Approved:
Jeanne M. Fox ^^ ' Date
Regional Administrator
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