PB98-963133
EPA 541-R98-137
March 1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Carroll & Dubies Sewage Disposal
Port Jervis, NY
8/24/1998
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION II
REGION II
AUG 24 1998
DATE: >w ti+ '**>
MBJECT: Explanation of Significant Differences for the Carroll & Dubies Sewage Disposal Superfund
' Site
*W Richard L. Caspe, P.E., Director vcpWAI
'^Emergency and Remedial ResponseT)ivision
10 Jeanne M. Fox
Regional Administrator
Attached is an Explanation of Significant Differences (ESD) for the Carroll & Dubies Sewage
Disposal Superfund site.
The March 31,1995 first operable unit (OU1) Record of Decision (ROD) called for the
excavation, treatment and long-term on-site containment of contaminated lagoon materials and
soil. The ROD also contained a contingency remedy that would require some of those wastes to
be transported off-site for treatment and disposal at a licensed hazardous waste facility, if studies
during the design indicated it was not practicable to treat these materials on-site.
Supplemental sampling activities were conducted in March 1997 during the remedial design
phase of the remedy. The results of the investigation confirm the findings of the previous
investigations regarding the types of wastes and contaminants present in the lagoons. It was also
found that the most highly contaminated waste disposed of in the lagoons, the industrial organic
waste, has a very distinct color and plastic-like texture. The industrial waste has the tendency to
bond together and separate from the surrounding solid waste in one mass. Therefore, the
bioslurry treatment of these wastes was not deemed to be practicable; it was determined that the
contingency remedy should be implemented. Based on these physical properties, and properties
of other wastes present, it was determined that the waste in and surrounding each lagoon can be
readily segregated into specific waste streams based on physical characteristics, making
additional off-site treatment more cost-effective.
The modified remedy expands the off-site treatment and disposal component of the contingency
remedy; more of the waste will be treated off-site. In addition, none of the waste will require on-
site containment and maintenance i.e., all of the subject waste will either be treated below health-
based levels, or will be disposed off-site at a licensed treatment and disposal facility. The
contaminated materials targeted for remediation remains the same. The attached ESD documents
these findings.
Please indicate your approval of the ESD by signing below. If you have any questions related to
the ESD, please call me at extension 4390.
Approved:
Jeanne M. Fo:
Regional A<
Attachment
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Explanation of Significant Differences
CARROLL & DUBIES SEWAGE DISPOSAL SITE
Town of Deerpark Orange County, New York
EPA
Region 2
August 1998
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 Pollution Contingency
Plan, if after the Environmental
Protection Agency (EPA) selects a
remedial action, there is a significant
change with respect to that action,
an explanation of the significant
differences and the reasons for such
changes must be published.
This Explanation of Significant
Differences (ESD) describes
changes to the March 31, 1995 First
Operable Unit Record of Decision
(OU1 ROD) for the lagoons and
surrounding impacted soils located
at the Carroll and Dubies Sewage
Disposal Superfund Site (the Site).
As discussed in detail below, this
ESD eliminates the necessity for the
long-term storage of contaminated
wastes at the Site by enhancing the
off-Site treatment and disposal
component of the original remedy,
while eliminating the pn-Site
containment cell. This ESD was
developed by EPA, as lead agency,
with support from the New York
State Department of Environmental
Conservation (NYSDEC). The
changes summarized herein are
described in the "Technical
Memorandum Expanded
Contingency Remedy Report"
dated May 1998 and the
"Sampling and Analysis Report"
dated June 1997, which should be
consulted for a more detailed
description of the proposed
changes to the selected remedy for
the lagoons and surrounding
impacted soils.
This ESD is being provided as a
supplement to those reports, to
inform the public of EPA's and
NYSDEC's changes to the selected
remedy for the lagoons and
impacted soils, and to solicit public
comment on the changes.
This ESD will become part of the
Administrative Record file for the
Site. The entire Administrative
Record for the Site, which includes,
among other things, the ROD, the
Technical Memorandum Expanded
Contingency Remedy, the
Sampling and Analysis Reports,
and other relevant documents, is
available to the public for a public
comment period, which begins on
August 31, 1998 and concludes on
September 29, 1998. These
documents are available for public
review at the following location:
Town Hall
Drawer A
Huguenot, New York 12746
Tel. (914) 856-2210
Hours: 8:00 a.m. - 4:00 p.m.
(Mon. - Fri.)
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components of the OU1 ROD
include:
• Excavation of all contaminated
materials from Lagoons 1,2,3, 4,
6, 7 and 8, as well as the
contaminated soils in the vicinity
of those lagoons.
• Treatment of excavated
soil/sludges which contain organic
constituents above the treatment
levels specified in the ROD via
on-Site ex-situ vapor extraction.
• Additional treatment of Lagoon 7
soils/sludges via on-Site ex-situ
bioslurry (treatment targeted
primarily for semi-volatile
contaminants).
• Stabilization/solidification of
soils/sludges which fail the
Resource Conservation and
Recovery Act's (RCRA) Toxicity
Characteristic Leaching
Procedure (TCLP) levels for
inorganic constituents, as
specified in 40 C.F.R. §262.24.
• Placement of treated and
untreated soil/sludge in a lined
and capped cell consistent with
the modified requirements of New
York Code of Rules and
Regulations Part 360. The base
of the cell was to have consisted
of a high density polyethylene
(HOPE) liner and a sand drainage
layer. The cell was to be sloped
to a leachate collection system.
The cap was to have consisted of
a low- permeability clay layer, an
HOPE membrane, a sand
drainage layer, and a topsoil
cover layer.
• Recommendations that deed and
well restrictions be imposed to
protect the integrity of the cap.
The OU1 ROD also states that
further treatability studies were
necessary to demonstrate that the
bioslurry process could reduce the
complex mix of organic chemical
constituents in Lagoon 7 to
remediation goals. Because of this
uncertainty, the OU1 ROD also
included a contingency remedy for
Lagoon 7 to be implemented if
treatability study results indicated
that bioslurry would not be effective
in reducing the levels of
contaminants in the Lagoon 7
materials, particularly, the semi-
volatile contaminants, to
remediation goals. The
contingency remedy includes
excavation, off-Site treatment and
off-Site disposal of Lagoon 7
materials at a licensed hazardous
waste treatment, storage and
disposal facility.
Supplemental sampling activities
were conducted in March 1997
during the remedial design phase
of the remedy. These
supplemental sampling activities
consisted of waste and subsurface
soil sampling, air monitoring and
sampling, and the collection of one
surface water sample from Lagoon
2. Twenty-four trenches were
excavated in specific areas of the
lagoons, 18 waste samples were
collected from within the lagoons,
and 25 soil samples were collected
from below the waste. While the
results confirmed the findings of
the December 1993 Remedial
Investigation Report (Rl), regarding
the types of wastes and
contaminants present in the
lagoons, it provided new
information regarding the ability to
segregate these wastes and
refined the estimated volume of
waste present. The results of the
investigation indicate that the most
highly contaminated waste
disposed of in the lagoons, the
industrial organic waste, has a very
distinct color and plastic-like
texture. The industrial waste has
the tendency to bond together and
separate from the surrounding solid
waste in one mass. Based on
these physical properties, and
properties of other wastes present,
it was determined that the waste in
and surrounding each lagoon can
be segregated into specific waste
streams based on physical
characteristics. Four waste types
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Lagoons 3. 7 and 8
Multi-colored industrial waste was
encountered in discrete areas of
Lagoons 3, 7 and 8. The colors
include pink, green, turquoise, white
gray and tan. The waste was
disposed in localized layers that
range from less than 1 inch to 2 feet
in thickness. In addition to being
distinct in color, the waste has
similar physical properties that
distinguishes it from the other waste
disposed in the lagoons, in that the
waste is highly plastic and greasy in
texture. Analysis of the industrial
waste in Lagoons 3 and 7 indicate
the presence of volatile organic
compounds (VOCs) above the
remediation levels. These VOCs
include benzene, 1,4-
dichlorobenzene, toluene, and
tetrachloroethene, and the semi-
volatile organic compound, di-n-
butylphthalate. The industrial waste
in Lagoons 3 and 7 did not contain
inorganic compounds in excess of
levels requiring excavation.
Lagoon 8 contains industrial waste
with VOCs similar to Lagoons 3 and
7. However, benzene, toluene, 1,4-
dichlorobenzene, trichloroethene,
and tetrachloroethene levels are
significantly lower than the
concentrations identified in Lagoons
3 and 7. The industrial waste found
in Lagoon 8 is also different from
that in Lagoons 3 and 7 in that it
contains elevated levels of
chromium.
The industrial wastes in Lagoons 3,
7 and 8 are mixed with municipal
sewage sludge/septage waste, and
solid waste. The sewage and solid
waste material is layered between
and around the industrial waste.
Based on the data collected from the
additional sampling activity, the
sewage and solid wastes have been
impacted by the disposal of
industrial waste.
The subsurface soil below the areas
that contain industrial waste in
Lagoons 3, 7 and 8 has also been
impacted by contaminants identified
in the industrial waste disposed in
the respective lagoons.
The impact to the subsurface soil in
Lagoon 3 appears to be limited to
three feet below the industrial
waste. In Lagoon 7, excavation
levels were exceeded in the
subsurface soil for di-n-
butylphthalate and
tetrachloroethene down to a depth
of 12 feet (approximately four feet
below the bottom of the lagoon
waste).
Subsurface soil below the bottom
of Lagoon 8 waste exceeded the
excavation level for chromium. The
vertical extent of the chromium
impact is approximately 20 to 23
feet below the ground surface in
Lagoon 8. This subsurface soil will
require excavation and removal.
Deeper soils are not believed to be
impacted by chromium or other
contaminants. In the event that
sampling indicates that deeper
soils exceed the excavation levels,
excavation will continue to the
water table, which has been
encountered at approximately 30 to
31 feet below ground surface in the
vicinity of Lagoon 8.
DESCRIPTION OF SIGNIFICANT
DIFFERENCES AND THE
REASONS FOR THOSE
DIFFERENCES
By this notice, EPA is modifying the
remedy selected in the OU1 ROD
The modified remedy expands the
off-Site treatment and disposal
component of the contingency
remedy; more of the waste will be
treated off-Site. In addition, none
of the waste will require on-Site
containment and maintenance i.e.,
all of the subject waste and soil will
either be treated below health-
based levels, or will be disposed
off-Site. The contaminated
materials targeted for remediation
and all the cleanup levels in the
OU1 ROD remain the same.
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In addition, the modified remedy
continues to utilize permanent
solutions and alternative treatment
technologies to the maximum extent
practicable for this Site.
PUBLIC PARTICIPATION
ACTIVITIES
EPA and NYSDEC rely on public
input to ensure that the concerns of
the community are considered.
Towards this end, EPA invites
comments or questions related to
this ESD. This document and
supporting information are available
to the public through their inclusion
in the Administrative Record for the
Site located at the addresses listed
above. The public comment period
begins on August 31, 1998 and
continues until September 29, 1998.
All comments or questions should be
directed to:
Maria Jon
Remedial Project Manager
Eastern New York Remediation
Section
U.S. Environmental Protection
Agency
290 Broadway, 20th Floor
New York, New York 10007-1866
Telephone: (212)637-3967
Fax:(212)637-3966
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