PB96-963126
EPA/ESD/R01-96/127
March 1997
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Davis Liquid Waste,
Smithfield, RI
7/19/1996
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DECLARATION FOR THE
EXPLANATION OF SIGNIFICANT DIFFERENCES
FOR CHANGING THE METHOD OF TREATING CONTAMINATED SOILS AND WASTES
FROM ON-SITE INCINERATION TO ON-SITE THERMAL DESORFTION
SITE NAME AND LOCATION
Davis Liquid Waste Superfund Site
Smithfield, Rhode Island
STATEMENT OF PURPOSE
This decision document sets forth the basis for the determination
to issue the attached Explanation of Significant Differences
•{"ESD") for the Davis Liquid Waste Superfund Site ("Site") in
Smithfield, Rhode Island.
STATUTORY BASIS FOR ISSUANCE OF THE ESP
Under Section 117(c) of CERCLA, 42 U.S.C. § 9617(0), if EPA
determines that the remedial action being undertaken at a site
differs significantly from the Record of Decision ("ROD") for
that site, EPA shall publish an explanation of significant
differences between the remedial action being undertaken and the
remedial action set forth"in the ROD and the reasons such changes
are being made. The National Contingency Plan (NCP)( 40 C.F.R.
§300.435(c), and EPA guidance (Office of Solid Waste and
Emergency Response ["OSWER"] Directive 93S5.3-02), indicate that
an ESD, rather than a ROD amendment, is appropriate where the
changes being made to the remedy are significant but do not
fundamentally alter the overall remedy with respect to scope,
performance, or cost. Because the adjustments to the remedy
selected in the ROD are significant but do not fundamentally
alter the overall remedy with respect to scope, performance, or
cost, the issuance of an ESD is appropriate in this case.
In accordance with Section 300.435 (c) of the NCP, this ESD and
supporting documentation will become part of the Administrative
Record which is available for public review at both the EPA
Region I Record Center in Boston, Massachusetts and the Town
Clerk's Office in Smithfield, Rhode Island.
OVERVIEW OF THE ESD
Based on the information and data generated since the issuance of
the September 29, 1987, ROD, one portion of the remedy as
described in the ROD has been modified:
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Excavation of Contaminated Soils and Wastes and On- site
Incineration
The ROD calls for the excavation and on- site incineration of
approximately 25,000 cubic yards of contaminated soils and
wastes . The ROD also evaluated the use of thermal
desorption for cleaning up the soils and waste at the Site.
Thermal desorption was not selected because at the time of
the ROD there was limited information available on the cost
and full-scale performance of this technology. Since the
ROD there 'has been extensive information gathered on the use
and performance of full-scale thermal desorption units at
other Superfund sites. The technology has been shown to be
very effective in removing volatile organic compounds and
capable of achieving the cleanup levels proposed 'for the
Site. Based on the successful performance of this
technology and updated cost information, EPA has selected
on- site thermal desorption as the means of treating
contaminated soils and waste at the Site. The use of
thermal desorption will be protective of human health and
the environment and will significantly reduce the overall
cost of implementing this component of the overall Site
remedy .
DECLARATION
For the foregoing reasons, by my signature below, I approve the
issuance of an Explanation of Significant Differences for the
Davis Liquid Waste Superfund Site in Smithfield, Rhode Island,
and the changes stated therein,
sift ,
~ _S/Y*~~ Linda M. Murphy , Director
/ Office of Site Remediation & Restoration
/
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Davis Liquid Haste Superfund Site
Final
Explanation of Significant Differences
for Changing the Method of Treating Contaminated Soils and Hastes
from On-Site Incineration to On-Site Thermal Desorption
July 1996
Prepared by EPA Region I
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TABLE OF CONTENTS
I. INTRODUCTION 1'
A. Site Name, Location, and Description 1
B. Identification of Lead and Support Agencies . 2
C. Citation of Legal Authority that Requires the
BSD 2
D. Summary of Significant Differences 2
E. Availability of Documents 3
II. SUMMARY OF SITE HISTORY, CONTAMINATION PROBLEMS, RESPONSE
HISTORY, AND SELECTED REMEDY 4
A. Site History and Contamination Problems ... 4
B. Response History 5
C. Summary of the Remedy as Originally Described
in the ROD 6
III. DESCRIPTION OF SIGNIFICANT DIFFERENCES AND THE BASIS FOR
THOSE DIFFERENCES 7
A. Summary of the Information that Gave Rise to the
Significant Differences 7
B. Proposed Change in Technology 9
IV. SUPPORTING AGENCY COMMENTS 10
V. AFFIRMATION OF THE STATUTORY REQUIREMENTS 10
VI. PUBLIC PARTICIPATION ACTIVITIES 10
APPENDIX A RI DEM Concurrence on the Draft ESD
APPENDIX B Response to Comments Received on the Draft ESD
APPENDIX C Comments Received on the Draft ESD
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EXPLANATION OF SIGNIFICANT DIFFERENCES
DAVIS LIQUID WASTE SUPERFTTOD SITE
SMITHFIELD. RHODE ISLAND
I. INTRODUCTION
This document constitutes a proposed Explanation of Significant
Differences ("ESD") between the remedial actions as specified in
the Record of Decision for the Davis Liquid Waste Site signed by
the Regional Administrator on September 29, 1987 ("ROD") and
those now planned under this proposed ESD. It also documents the
conditions that gave rise to the need for this ESD.
A. Site Name, Location, and Description
Site Name: Davis Liquid Waste Superfund Site
Site Location: Smithfield, Rhode Island
Site Description: The Davis Liquid Waste Superfund Site (the
"Site") is located en the property of William and Eleanor Davis
in a semi-rural residential section of the Town of Smithfield,
Providence County, Rhode Island. The approximately 10 acre site
served as a disposal location for a variety of liquid and solid
wastes containing hazardous substances during the 1970's and
early 1980's. Mr. Davis permitted the dumping of the contents of
drums and tank trucks into unlined lagoons and seepage pits at
the Site. Periodically, contaminated soils were excavated and
dumped at several locations on-site and covered with available
soil. The Site and adjacent areas have also served as a staging
and disposal location for numerous discarded tires. Estimates of
the number of tires being stored on the property range from
approximately 10 to 30 million.
Site investigations by the State of Rhode Island ("State") and
the United States Environmental Protection Agency ("EPA") in the
late 1970's and early 1980's helped provide sufficient
information to have the Site placed on the Interim National
Priorities List ("NPLM) in June of 1982. These initial studies
identified that contaminants from the Site were impacting nearby
groundwater and surface water. Some contamination was detected
in the private wells of nearby residences who depend on the
groundwater as their sole source of potable water. On
December 31, 1982, EPA placed the Site on the "Proposed NPL" of
hazardous waste sites, and listed it as a final NPL site in
September of 1983.
The Site is bounded on the east and west by forested uplands, and
on the north and south by wetlands and swamp areas. Land within
one mile of the Site is semi-rural in nature and is dominated by
low density residential dwellings. Residential development in
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Explanation of Significant Differences
D«vi» Liquid Watte Superfund Site
JUly 1996
the area has increased in the last five to ten years and has
included the construction of larger subdivisions as well.
Additional description of the Site can be found in the ROD.
B. Identification of Lead and Support Agencies
Lead Agency: United States Environmental Protection Agency
Contact: Neil Handler
Remedial Project Manager
(617) 573-9636
•
Support Agency: Rhode Island Department of Environmental
Management, Division of Site Remediation
{"RI DEM")
Contact: Matt: DeStef ano
Project Manager
(401) 277-3872 Ext. 7141
C. Citation of the Legal Authority that Requires the ESD
Under Section 117(c) of the Comprehensive Environmental Response,
Compensation and Liability Act of 1980 ("CERCLA"), 42 U.S.C.
§ 9617(c), if EPA determines that the remedial action being
undertaken at a site differs significantly from the Record of
Decision for that site, EPA shall publish an explanation of
significant differences between the remedial action being
undertaken and the remedial action set forth in the ROD and the
reasons such changes are being made. The National Contingency
Plan (NCP), 40 C.F.R. §300.435(c), and EPA guidance (Office of
Solid Waste and Emergency Response ["OSWER"] Directive 9355.3-
02), indicate that an ESD, rather than a ROD amendment, is
appropriate where the changes being made to the remedy are
significant but do not fundamentally alter the overall remedy
with respect to scope, performance, or cost. Because the
adjustments to the remedy selected in the ROD are significant but
do not fundamentally alter the overall remedy with respect to
scope, performance, or cost, the issuance of an ESD is
appropriate in this case.
D. Summary of Significant Differences
EPA issued this proposed ESD because of changes in the remedy
selected in.the ROD for the cleanup of contamination in soil.
Since the ROD there has been extensive information gathered on
the use and performance of full-scale thermal desorption units at
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Explanation of Significant Diff«r«ne««
Davia Liquid Wact* Suparfund Sit*
July 1996
other Superf ur.d sites. The technology has proven very effective
in treating soils contaminated with volatile organic compounds
and has achieved cleanup levels below those identified for the
Site. Based on the successful performance of this technology and
updated cost information, EPA has selected on-site thermal
desorption as the means of treating contaminated soils and waste
at the Site. The use of thermal desorption will be protective of
human health and the environment and will significantly reduce
the overall cost of implementing this component of the overall
Site remedy. The ROD calls for the excavation and on-site
incineration of contaminated soils and wastes which are above the
total volatile organic concentration of two (2) parts per million
("ppm"). EPA through this BSD still proposes the excavation and
on-site treatment of contaminated materials to the levels
identified in the ROD, but now proposes that treatment be
achieved using a different thermal technology, thermal
desorption.
Because thenr.al desorption, like incineration, removes
contaminants through a thermal process, the use of thermal
desorption dees not fundamentally alter the remedy selected in
the ROD.
E. Availability of Documents
This ESD and supporting documentation shall become part of the
Administrative Record for the Site. Information pertinent to
EPA's decision making process in publishing this proposed ESD is
available for public review at information repositories at the
following locations:
EPA Records Center
90 Canal Street, First Floor
Boston, Massachusetts
(617) 573-5729
Hours:
Mon-Fri: 10:00 a.m. - 1:00 p.m. and 2:00 p.m. - 5:00 p.m.
Smithfield Town Clerks Office
64 Farnum Pike
Smithfield, Rhode Island
(401) 233-1000
Hours:
Mon-Fri: 9:00 a.m. - 4:00 p.m.
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Explanation of Significant Difference*
Oavi« Liguid Kaete Super fund Site
July 1996
II. SUMMARY OF SITE HISTORY. CONTAMINATION PROBLEMS. RESPONSE
HISTORY, AND SELECTED REMEDY
A. Site History and Contamination Problems
During the 1970's and the early 1980's, site owner William Davis
used the Site to dispose of a variety of liquid and solid wastes
containing hazardous substances. Mr. Davis permitted the dumping
of the contents of drums and tank trucks into unlined lagoons and
seepage pits at the Site. The proximity of these disposal areas
to the water table and surrounding wetland areas allowed
contaminants to migrate and infiltrate into the surface water and
groundwater. Periodically, contaminated soils were excavated and
dumped at several locations on-site and covered with available
soil. Because very few records exist concerning the waste
products disposed of and the disposal practices, it is difficult
to estimate the volume of waste disposed of at the Site. General
categories of wastes believed to have been disposed of at the
Site include solvents, inks, laboratory Pharmaceuticals.,
manufacturing residues, miscellaneous chemical processing wastes,
and waste oils. •
Site investigations by the State and EPA in the late 1970's and
early 1980's revealed the presence of high levels of organic
contamination in the surface water exiting the Site and in some
of the nearby residential wells. The contaminants detected
include tetrachloroethylene, chloroform, trichloroethylene, and
benzene. These investigations led to the proposed listing of the
Site on the NPL in 1982 and final listing of the Site in
September of 1983. After listing, the State took the initial
lead in investigating the-nature and extent of contamination at
the Site. In order to assist the State with access issues, EPA
took over the lead for project management of the Remedial
Investigation/Feasibility Study in October, 1984.
The Remedial Investigation ("RI"), which was completed in
November of 1986, identified extensive contamination of the soil,
groundwater, sediment, and surface water at the Site. The RI
also identified areas of the Site where drums and other types of
containerized wastes were buried. Contamination of each media
consisted primarily of volatile organic compounds including
tetrachloroethylene, trichloroethylene, ethylbenzene, benzene,
toluene, and xylene.
Contaminants were found in both the shallow overburden aquifer
and the deeper bedrock aquifer. Both of these aquifers were used
by residents near the Site as their sole source of potable water.
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Explanation of Significant Differences
Davi* Liquid Wa«t« Superfund Sit*
July 1996
Currently no public water supply is available. The state of
Rhode Island has been providing bottled water to some of the
residents near the Site since the early 1980's.
B. Response History
Although the disposal activities of the property owner, Mr.
Davis, are believed to have ended by the early 1980's, there were
still numerous drums being stored at the Site at the time the RI
was initiated in 1984. EPA determined that many of these drums,
which were in various stages of decay, still contained hazardous
substances. To address these drums, EPA initiated a removal
action in August, 1985. The removal action consisted of the
sampling, analysis, packing, and disposal of approximately 600
intact and crushed drums.
The remedy identified in the ROD consists of three primary
components: 1) an alternative water supply for residents affected
or potentially affected by groundwater contamination from the
Site, 2) an on-site groundwater extraction and treatment system,
and 3} the excavation and on-site incineration of contaminated
soils and wastes. In July, 1988, EPA initiated work on the
construction of the alternative water supply. Most of the
construction work, including the installation of the transmission
mains, distribution mains, and a storage tank was completed as of
September, 1990. To provide water to this new service area it
was necessary for EPA to modify the Town of Smithfields' existing
water system and design two new booster pump stations and
renovate a third existing pump station. This design work was
completed in August, 1995 and funding for construction was made
available in March, 1996. The construction contract was awarded
in June, 1996 and is expected to take approximately 15 to 18
months to complete once the notice to proceed is issued.
The design of the on-site groundwater extraction and treatment
system is approximately 90% complete and is anticipated to be
completed by the Fall of 1996. Design work for treatment of
contaminated soils and wastes has been delayed because of the
presence of tires stored over these areas.
The Site has been used by-the property owner as a storage and
staging area for discarded tires. Estimates for the number of
tires being stored at the property range from approximately ten
to thirty million. Approximately one-third of these tires are
being stored over areas which EPA believes may contain
contaminated soils. In December of 1994, the Superior Court of
the State of Rhode Island issued an order requiring Mr. Davis to
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Explanation of Significant Differences
Oavi« Liquid Haste Superfund Site
1996
begin removing tires from the Site. During the removal of tires
in early 1995, Mr. Davis notified EPA and RI DEM that he had
discovered approximately nine drums in various stages of decay.
EPA and RI DEM sampled the drums and found that a number of them
contained hazardous substances similar to those detected in the
soil and groundwater at the Site during previous sampling
activities. As a result the drums were disposed of through a
removal action authorized by the EPA Regional Administrator in
April of 1995.
C. Summary of the Remedy as Originally Described in the
ROD
The ROD described in detail each of the alternatives evaluated
for remediating the contamination at the Site and the chosen
alternative for each contaminated media of the Site. The chosen
remedial alternatives are summarized below.
Source Control Component - Excavation of approximately 25,000
cubic yards of raw waste and contaminated soils located in the
unsaturated zone and treatment on-site in a mobile incineration
facility. All soils and wastes with volatile organic
concentrations above 2 ppm would be excavated and treated by
incineration to reduce total volatile organic concentrations to
below the 2 ppm cleanup level. Treated soils would be tested for
EP toxicity. Those soils with concentrations that are below the
EP toxicity levels would be used to back fill excavated areas.
The soils with concentrations above the EP toxicity levels would
be placed in a RCRA Subtitle C landfill on-site. The source
control component of the remedy was anticipated to take one year
to design and construct and two years of operation to treat the
estimated 25,000 cubic yards of material.
Management of Migration Components - l) The design and
construction of an alternative water supply to serve those
residents impacted by groundwater contamination from the Site, as
well as those areas that are down gradient from the contaminated
plume that could potentially be affected. The proposed project
consists of a connection to the existing Town of Smithfield water
supply system, requiring approximately 2,100 feet of transmission
main, 21,000 feet of distribution mains, a storage tank, and a
booster pumping station. The estimated population to be served
ultimately is approximately 475 persons. 2) The active
restoration of the overburden and bedrock aquifers contaminated
with volatile organic compounds using on-site treatment involving
air stripping and carbon adsorption and recirculation of treated
water to the aquifer. Additional components of the treatment
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Explanation of Significant Diff«r«nc«a
D«vi« Liquid Waat* Suparfund Site
July 1996
train may address the removal of oils, floatable solids, and
inorganic compounds. A cleanup level of 5 parts per billion has
been established for benzene, trichloroethylene, and
tetrachloroethylene. EPA estimated in the ROD that this target
remediation level could be achieved within 5 to 10 years.
III. DESCRIPTION OF SIGNIFICANT DIFFERENCES AND THE BASIS FOR
THOSE DIFFERENCES
A. Summary of the Information that Gave Rise to
Significant Differences
On-site low temperature soil treatment {e.g., thermal desorption)
and on-site thermal destruction (e.g., incineration) were both
evaluated as part of the detailed analysis for source control
components in the April 1987, Feasibility Study (FS) for the Site
and the ROD. The technologies were evaluated by EPA for their
performance, technical reliability, implementability and
constructability, safety, compliance with applicable or relevant
and appropriate requirements (ARARs), and protectiveness of human
health and the environment. Also given important consideration
were the overall costs of each alternative.
The principal differences between these two technologies, as
identified in the FS, was that incineration was given a higher
rating for performance and reliability than thermal desorption
(e.g., a rating of high versus medium). It appears that this
difference in rating was based on the fact that at the time of
the FS, the thermal desorption technology was still in its
infancy and there was a limited amount of performance data
available from full-scale operating systems.
Since the FS, thermal desorption has been widely used at
Superfund sites to treat contaminated soils similar to those
found at the Site. The performance data gathered from other
sites since the FS has shown this technology to be very effective
in removing volatile organic compounds and capable of achieving
the cleanup levels proposed for the Site. The effectiveness of
thermal desorption as well as the appropriateness of its use at a
site such as the Davis Liquid Waste Site is further affirmed by
the information and recommendations presented in the September
1993, OSWER Directive 9355.0-48FS Guidance on "Presumptive
Remedies: Site Characterization and Technology Selection for
CERCLA Sites with Volatile Organic Compounds in Soils" (EPA 540-
F-93-048) . The Presumptive Remedy Guidance identifies that for
sites containing VOC-contaminated soil if the material is to be
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Explanation of significant Differences
Davis Liquid Ha«t« Sup«r£und Site
July 1995
excavaced, than thermal desorption is the preferred technology
for treatment.
EPA did consider as part of its development of the ESD the
application of soil vapor1extraction (SVE) at the Site. SVE, an
in-situ treatment process, is one of the other technologies
recommended in the Presumptive Remedy Guidance. Although SVE has
been proven to be effective and appropriate to use at many
Superfund Sites it was not believed to be the most appropriate
technology to be used at this Site because of the presence of
buried raw wastes, drums, and/or containers. These buried
materials are not amenable to treatment using SVE. In order to
ensure that these buried materials will stop contaminating the
groundwater they must be excavated and treated and disposed of.
The excavation and thermal desorption of these wastes provides a
level of protectiveness and certainty which cannot be achieved at
the Site by using SVE.
The other principal factor which at the time of the FS appears to
have affected the selection of incineration over thermal
desorption was cost. The FS identified that the total estimated
present worth cost of on-site incineration and on-site low
temperature soil treatment were $14,912,000 and $16,098,000
respectively. With the increased usage of thermal desorption
since the FS, the cost of implementing this technology has
decreased. As identified in the OSWER Guidance on Presumptive
Remedies, the average cost per ton for treatment using thermal
desorption is $250 and incineration is $400. Thus when the unit
costs are multiplied by the estimated volume of material
requiring treatment (e.g., 25,000.yd3 or 40,500 tons) thermal
desorption could provide a savings of millions of dollars.
A Responsible Party for the Site, after petitioning EPA to reopen
the administrative record, has completed additional pre-design
work including a treatability study of the effectiveness of
thermal desorption on Site soils. The results of the
treatability work confirm the effectiveness of thermal desorption
in achieving the cleanup goals identified in the ROD.
In summary, the use of thermal desorption at the Site would
represent a significant savings and still provide a level of
protection for human health and the environment equal to that
achieved by incineration.
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Explanation of Significant Differences
Davia Liquid Haate Superfund Site
1996
B. Proposed Change in Technology
All contaminated soils and wastes with volatile organic
concentrations at or above 2 ppm will be excavated and treated
on-site using thermal desorption to reduce total volatile organic
concentrations to below the 2 ppm cleanup level. Treated soils
will be tested for their toxicity using the Toxicity
Characteristic Leaching Procedure (TCLP). Those soils with
concentrations that are below the TCLP regulatory levels will be
used to back fill excavated areas. The soils with concentrations
above the TCLP regulatory levels will either be placed in a RCRA
Subtitle C landfill on-site or disposed of off-site at an EPA
approved facility. The source control component of the remedy is
anticipated to take 12 to 18 months to design and construct and
then approximately one year to treat the estimated 25,000 cubic
yards of material.
Since the ROD there has been some additional sampling at the Site
which may indicate that the volume of material requiring
treatment is greater than that estimated in the ROD. However,
the sampling has" been limited by the presence of tires over much
of the Site. Therefore, until these tires are removed a more"
definitive estimate of the volume of soil requiring treatment can
not be made.
The successful application of thermal desorption at Superfund
sites has been demonstrated over the past 10 years and has
included extensive evaluations under the EPA Superfund Innovative
Technology Evaluation program. Thermal desorption is considered
by EPA as a proven means for removing volatile organics from
soils, sludge, and sediments and can achieve the desired removal
needed to meet the cleanup goals for the Site. Thermal
Desorption is identified as the preferred technology for
treatment in the EPA Presumptive Remedy Guidance for sites
containing VOC-contaminated soil requiring excavation.
Incineration and thermal desorption are similar in that they both
use heat to remove contaminants from the soil. The technologies
differ by the amount of heat that is applied. Incineration heats
VOCs to the point where they are destroyed or decomposed while
thermal desorption uses a lower temperature to physically drive-
off and remove contaminants from the media being treated. The
contaminants removed must then be collected and treated
separately. In many instances this treatment occurs at a
separate off-site location.
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Explanation of Significant Differences
Davii Liquid Waste Superfund Site
July 1996
Thermal desorptior. is more limited as to the size of the material
it can treat and therefore will require a more extensive
materials separation process than incineration. In addition,
thermal descrptior. will be unable to treat any drums or large
containerized wastes encountered during excavation. Therefore,
these materials will either have to be shredded and treated on-
site or taken to an off-site location for disposal. The quantity
of material identified in the ROD as needing off-site disposal i.s
estimated to be 2,500 cubic yards. Even with the additional
costs of having to dispose of this material, the cost savings for
employing thermal desorption over incineration are nonetheless
expected to be substantial.
IV. SUPPORTING AGENCY COMMENTS
The Rhode Island Department of Environmental Management Division
of Site Remediaticn has participated with EPA in developing the
change to the selected remedy which are described herein and
concurs with the approach adopted by EPA.
V. AFFIRMATION OF THE STATUTORY REQUIREMENTS
EPA has determined that the selected remedy specified in the ROD,
with the above-described changes, 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 as identified in the ROD, and is cost-
effective. In addition, the revised remedy uses permanent
solutions and alternative treatment technologies to the maximum
extent practicable for this Site.
VI. PUBLIC PARTICIPATION ACTIVITIES
This BSD, accompanied by supporting information and analysis, was
made available for public review and comment for 30 days at the
locations and times listed in Section E., above. During the 30-
day time period EPA received two sets of comments. At the
request of one of the individuals commenting, the comment period
was extended by an additional 23 days during which time one set
of supplemental comments was received by EPA.
A copy of the comments and EPAs' responses to the comments are
attached to the BSD as Appendices C and B, respectively. All of
the comments submitted came from representatives of parties who
10
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Explanation of Significant Differences
Davis Liquid Hast* Superfund site
July 1996
are involved in dontribution litigation with respect to the Site.
In general the comments were supportive of changing the method of
on-site treatment from incineration but all sets of comments
expressed a preference for using soil vapor extraction {SVE) over
thermal desorpcion as the technology of choice. EPA has
identified in Section III.A., of the BSD and Appendix B to the
ESD the reasons why it selected thermal desorption in lieu of SVE
for the Site.
In accordance with Section 117 (d) of CERCLA, this ESD will become
part of the Site's Administrative Record which is available for
public review at both the-EPA Region I Record Center at 90 Canal
Street in Bostsn, Massachusetts (617/573-5729) and at the
Smithfield Town Clerk's Office at 64 Farnum Pike in Smithfield,
Rhode Island (401/233-1000).
11
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APPENDIX A
RI DEM Concurrence on the Draft ESD
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STATE OF RHODE ISLAND AND PROVIDENCE PLANTATIONS
Department of Environmental Management
DIVISION OF SITE REMEDIATION
291 Promenade Street
Providence. fU. 02908-5767
7 March 1996
Ms. Linda Murphy, Director
Office of Site Remediation and Restoration
U.S. Environmental Protection Agency - Region 1
John F. Kennedy Federal Building (HSV-CAN5)
Boston, MA 02203-2211
RE: Davis Liquid Waste Superfund Site, Smithfieid, Rhode Island
Dear Ms. Murphy,
This Division has conducted a review of the Draft Explanation of Significant Differences (ESD)
for the source control component of the remedy at the Davis Liquid Waste Superfund She. As
a result of this review, our agency has generated the attached review comments. With the
incorporation of our enclosed technical comments, the Division is hi favor of proceeding within
the framework of this ESD.
If you have any questions regarding these issues, please feel free to contact me at (401) 277-
3872, extension 7100.
Sincerely,
Tertence Gray, P.E.,
Division of Site Renn
cc: J. Fester, RIDEM-DSR
R. Boynton, USEPA-Region 1
dzva&convindd
Tclrphone {-JO I) 277-3872 / FAX 277-2017
TcVcomimvnicauon Device tor the Deaf 277-6800
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Davis Liquid Waste Superfund Site
Draft Explanation of Significant Differences (Version 1)
January 1996
Division of Site Remediation Comments:
SPECIFIC COMMENTS:
1. Page 7, Section Q. (Q Summary of Remedy as Originally Described in the ROD:
Sentence 1, Paragraph 1:
"The active restoration of the overburden and bedrock aquifers contaminated with volatile
organic compounds using onsite treatment involving air stripping and carbon adsorption
and recirculation of treated -water to the aquifer."
It should be clarified that treated water will be discharged into a nearby surface water,
not injected back into the aquifer.
2. Page 10, Section V, Affirmation of the Statutory Requirements:
Paragraph 1:
"... complies with Federal and State requirements that are applicable or relevant and
appropriate to this remedial action, and is cost-effective."
It should be made clear in this section that the ESD also meets all ARARs identified at
the time the original ROD was signed.
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APPENDIX B
Response to Comments Received Pursuant to the
Draft Explanation of Significant Differences
for Changing the Method of Treating Contaminated Soils and Wastes
from On-site Incineration to On-Site Thermal Desorption
Davis Liquid Waste Superfund Site
Smithfield, Rhode Island
July 1996
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TABLE OF CONTENTS
I. INTRODUCTION
II. SPECIFIC COMMENTS AND RESPONSES 1
A. Procedural Comments ............. 1
B. General Comments 4
C. Technical Comments 6
ATTACHMENT #1 THERMAL DESORPTION COST ESTIMATE
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I. Introduction
On April 9, 1996 EPA issued for public comment a draft
Explanation of Significant Differences (BSD) between the remedial
action to be undertaken at the Davis Liquid Waste Superfund Site
(the "Site") and the remedial action as set forth in the September
29, 1987 Record of Decision (ROD) for the Site. The change
consists of using on-site thermal desorption as the means of
treating contaminated soils and wastes at the Site in place of on-
site incineration.
During the 30-day public comment period EPA received two sets of
comments on the draft ESD. At the request of one of the
individuals commenting, the comment period was extended by an
additional 23 days during which time one set of supplemental
comments was received by EPA. A copy of the comment letters are
included as Appendix C to the ESD, and will be referenced herein,
respectively, as 1) Brenan, 2} BFI-RI, and 3) Brenan Supplemental.
All of the comments submitted came from representatives of parties
who are involve'd in contribution litigation with respect to the
Site. In general the comments were supportive of changing the
method of on-site treatment from incineration but both sets of
comments expressed a preference for using soil vapor extraction
(SVE) over thermal desorption as the technology of choice.
It should be noted that EPA's responses to comments are confined
co those comments or portions of comments which deal with the
changes being discussed in the proposed ESD. Therefore, comments
outside of the scope of the proposed ESD, such as those dealing
with the management of migration components of the overall site
remedy, are not addressed. To the extent that comments overlap or
reiterate similar concerns, EPA has attempted to group these
comments together and provide one comprehensive response.
II. Specific Comments and Responses
A. Procedural Comments
1. EPA'a comment period provides inadequate time for the
litigants in the Davis case to review, consider, and evaluate all
of the documentation and data identified in the original ROD
Administrative Record and the Proposed Administrative Record for
the ESD. (Brenan, Brenan Supplemental)
Section 300.435 (c) of the NCP and Section 117 (c) of the
Comprehensive Environmental Response, Compensation and Liability
Act of 1980 (nCERCLAn) clearly identify the public participation
and community relations requirements for an ESD. To summarize, the
requirements consist of 1} the publication of a notice in a major
local newspaper of general circulation briefly summarizing the ESD
and the reasons for proposing the change and 2} making the ESD and
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supporting information available to the public as part of the
administrative record established under Section 300.815 in the
local information repository. These requirements were met on April
9, 1996 when EPA published a notice of the proposed ESD in the
Providence Journal and made the ESD as well as supporting
information available to the public at the local repository in the
Smithfield Town Hall.
In an effort to increase the level of public involvement and
participation with respect to the ESD, EPA at its discretion
initiated a 30-day comment period during which it accepted comments
from the public on the proposed ESD. No comments were received
from the public during this time period other than those provided
by counsel representing two parties (out of approximately 129
parties) involved in contribution litigation with respect to the
Site. It was at this time that one of the individuals commenting
(i.e., Brenan) requested additional time to review and respond to
the proposed ESD. EPA, although not required to do so; agreed to
extend the comment period by another 23 days and received one set
of additional comments during that time (i.e., Brenan
Supplemental). A Freedom of Information Act request was also
submitted on behalf of Mr. Brenan during the extended comment
period requesting copies of documents from EPA related to the
proposed ESD. The request was responded to by EPA and documents
provided -within the time prescribed by law.
As can be seen by the activities described above, EPA more than
complied with the spirit as well as the letter of CERCLA for
providing public participation in the ESD process. The
administrative process pursued here by EPA clearly conforms with
the discussion provided in the Preamble to the NCP [See Section
300.435(c)(2)] and attempts to balance the public's continuing need
for information about, and input into, post-ROD remedial action
decisions, with the agency's need to move forward expeditiously
with design and implementation of the remedy after fundamental
decisions have been made in the ROD; EPA has provided more than
sufficient time for the individuals commenting to review, consider,
and evaluate the documentation and data identified in the original
ROD Administrative Record and the Proposed Administrative Record
for the ESD.
It is worth noting that in 1991, the parties represented by the'
individuals commenting were named as third party Defendants in cost
recovery litigation related to the Site. Since then, there has
been sufficient time for the litigants to review the documentation
and data contained in the Administrative Record for the Site.
2. The proposed Administrative Record for the BSD appears to be
incomplete in that documents including the draft Scope of Work for
the soil remedy submitted by one party as well as related documents
and/or deliverables such as the Preliminary Remedial Design for the
soil remedy have not been included. EPA needs to. provide the
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public with the status of the remedial action, the coats incurred
to date, the projected costs, and an explanation of the
appropriateness of the 1987 ROD remedy given the current conditions
at the site nearly 10 years later in 1996. (Brenan)
In conformance with CERCLA and the NCP, EPA made available as part
of the Administrative Record all of the supporting information
which formed the basis of the decision to issue the proposed ESD.
The specific documents mentioned or the additional information
requested by the commenter did not form, and were not needed to
form the basis of EPA's decision and therefore were not included in
the Administrative Record.
3. The public is entitled to know EPA's beat current estimation
as to the volumes of contaminated soils and/or waste at the site
which may have to be remediated, the extent and current conditions
of groundwater contamination including whether that contamination
has diminished or increased or any longer poses a potential riskf
and the projected time frame for addressing both soil and
groundwater contamination, fBrenan)
The information requested by the commenter regarding the extent of
contamination and estimated volume of contaminated soils and/or
wastes is included in "Pre-Design Engineering Report I" and "Final
Pre-Design Engineering Report II" which are included as part of the
Administrative Record, for .the proposed ESD. The projected time for
EPA to treat the soils and wastes at the Site using thermal
desorption is approximately 12 to 15 months, similar to that
estimated for on-site incineration in the ROD.
4. The proposed BSD appears to be influenced by factors other
than technical and scientific concerns. We are concerned that the
proposed BSD is, at least in significant part, a product of
settlement negotiations and financial tradeoffs between the United
States and certain litigants rather than a reasoned decision with
respect to the costs and benefits of technologies available in
1996. In this regard, there is correspondence from July 24, 1995,
which is not in the Administrative Record but should be, which sets
forth the United States' positions on pump and treat, soil vapor
extraction, and low temperature thermal desorption. (Brenan, Brenan
Supplemental)
EPA has clearly stated in the ESD the basis for proposing the ESD.
The change in the remedy described in the ESD is solely based on
sound scientific, technical, and economic reasoning. Based on such
reasoning, EPA has concluded that the use of thermal desorption at
the Site will provide a level of protection for human health and
the environment equal to that achieved by incineration, and will do
so in a more cost-effective manner.
The correspondence referred to by the commenter was from the
Justice Department to certain parties to the litigation for
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purposes of settlement discussions. The correspondence set forth
the intentions of Justice Department trial counsel and EPA staff
regarding negotiations, and their understanding of certain of
CERCLA's requirements as it related to the negotiations. As such
the correspondence did not form any basis for EPA's decision and
therefore was not included in the Administrative Record,
B. General Comments
1. The BSD, aa proposed, is too narrow in focus and fails to
consider appropriate remedial technologies. For on-site soils
where VOCs are the constituents of concern, EPA's presumptive
remedy is soil vapor extraction (SVE) and this technology should,
at a mi rtf ****** f have been evaluated. (Brenan, BFJ-RT, Brenan
Supplemental)
EPA evaluated the use of SVE in the Feasibility Study (FS) and
again reconsidered its use more recently during EPA's development
of the proposed BSD. EPA' believes that SVE is certainly an
effective and appropriate technology to use at many Superfund Sites
but does not believe it is the most appropriate technology to be
used at this Site. The primary reason for this is that during the
Remedial Investigation (RI) EPA found that there were portions of
the Site in which raw wastes and drums/containers were buried.
These areas, which are scattered across the Site, are not amenable
to treatment using SVE. In order to ensure that these raw wastes
and drums/containers will stop contaminating the groundwater, they
must be excavated and treated or disposed of. Therefore, the
excavation and thermal desorption of these wastes provides a level
of protectiveness and certainty which cannot be achieved at the
Site by using SVE.
An additional concern regarding the use of SVE on the remaining
portions of the Site relates to its ability to meet cleanup levels.
The concern arises partially from the close proximity of the water
table to the ground surface and the reduced effectiveness of SVE
under such conditions. The application of SVE in these areas will
at best delay the clean up process and may ultimately mean that
cleanup levels can not bfe achieved using SVE alone. If SVE were
attempted, and then failed, any hoped for cost savings could well
be eliminated if another source control remedial technology had to
be employed.
For these reasons, it is not in the best interests of the public or
environment to use SVE to cleanup the Site or portions of the Site.
SVE does not achieve the same overall level of protectiveness and
reliability that EPA believes can be achieved at the Site through
excavation and the use of thermal desorption as proposed in the
BSD.
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2. The BSD is flaved and its conclusions are in error because the
proposed BSD presents an inaccurate comparison of the coats of
incineration to the costs of its selected option, low temperature
thermal desorption. The'use of unit costs, as presented in the
presumptive remedy guidance is far too gross an estimate to be used
when millions of dollars are under consideration. A cost estimate,
at least as detailed as that presented in the ROD and FS, needs to
be presented. (Brenan)
While EPA believes that unit costs alone provide a sufficient basis
for comparing thermal desorption to incineration costs, EPA has
prepared a more detailed cost estimate for the on-site construction
and implementation of thermal desorption at the Site (See
Attachment #1} . The pre-treatment and post-treatment activities
for thermal desorption are similar to those of incineration. Both
technologies require mobilization and demobilization to and from
the Site, have similar processing area requirements, and involve
the excavation, sorting, and disposal of treated materials. The
costs for these activities are therefore expected to be similar
with the exception of the costs associated with the disposal of
materials unsuitable for treatment. Thermal desorption is expected
to incur higher disposal costs for these materials given the
limitations on the size and types of materials that it can treat.
These disposal costs have been accounted for in the attached cost ,•
estimate.
The major cost difference between the two technologies is reflected
in the unit cost of treatment as shown in Item 5 of Attachment #1.
Based upon the average cost of treatment (e.g., $250/ton) as
identified in the Presumptive Remedies Guidance (EPA 540-F-93-048)
the cost to treat contaminated materials at the Site using thermal
desorption is estimated to be approximately $9.1 million (See Item
5 of Attachment #1) . The corresponding cost of incineration would
be approximately $16.2 million based upon the average cost (e.g.,
$400/ton) identified in the Presumptive Remedies Guidance. Even
with the inclusion of the off-site disposal costs of approximately
$3.2 million (See Item 6 of Attachment #1), and the assumption that
incineration would entail no off-site disposal costs, the use of
thermal desorption is expected to provide an overall cost-savings
of approximately $4 million.
It should be noted that the cost of treatment for both technologies
is volume dependent. Because the unit cost of thermal desorption
is less than that of incineration the cost savings will increase or
decrease roughly in proportion to any increase or decrease in the
volume of material requiring on-site treatment.
The more detailed cost estimate supports EPA's conclusions as set
forth in the proposed ESD,' i.e., that the use of thermal desorption
versus incineration at the Site will provide a more cost-effective
means for the cleanup of the Site without sacrificing the
protectiveness and reliability of the remedy.
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C. Technical Comments
1.. The BSD does not describe nor summarize the 'information and
data generated since the issuance of the September 29, 1987 ROD, "
nor does it indicate the sources of this information which formed
the basis of EPA's proposed BSD. (Brenan)
EPA, in conformance with CERCLA and the NCP, has included all of
the information which formed the basis of its decision to issue the
proposed BSD, including pertinent post-ROD data, in the
Administrative Record for the BSD. The sources of such information
are indicated on the documents contained in the Administrative
Record. Although some of the documents may contain additional data
pertaining to other components of the overall site remedy it is the
data which relates to the'source control component of the overall
site remedy that is being considered here.
2. the statement by EPA that 'EPA has selected on-site thermal
desorption as the means of treating contaminated soils and waste at
the Site" is not entirely accurate. As indicated in the ESD, there
are approximately 2500 yd? of "waste* estimated to still be on site
which are not treatable by thermal desorption. The ESD fails to
consider the cost for treatment of this material and therefore, the
performance and cost of LTTD have not been appropriately;
considered. (Brenan) '•
Contrary to what the commenter has stated, the costs associated
with the off-site treatment and disposal of the estimated 2500 yd3
of "waste" which may not be"amenable to thermal desorption have
been factored into EPA's cost analysis (See Item 6 of Attachment
#1) and overall decision to propose this change. Even with the
"waste" disposal cost included, the use of thermal desorption still
provides a significant cost-savings over incineration without
sacrificing any of the protectiveness or reliability. It should be
noted that, depending on which thermal desorption technology is
selected, the volume of drums or large containerized wastes
requiring off-site treatment and disposal may be significantly
reduced from the quantity shown above, thereby providing additional
cost savings.
3 . There appears to be a discrepancy between the si te size in the
ROD (15-acres) and in the ESD (10-acres). There is no explanation
in the ESD as to which 5 acres have been eliminated for the
purposes of the ESD or why. (Brenan)
The size of the site identified in the ROD is different from that
identified in the BSD because the ROD language, which was taken
from the Remedial Investigation Report, refers to the approximate
size of the area studied by EPA during the Remedial Investigation
(RI) . The size of the site identified in the ESD encompasses the
approximate area where excavation and activities to support the
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excavation and treatment will take place, an area expected to be
smaller in size than the area studied during the RI.
4. By selecting the LTTD process, the EPA apparently has
concluded that semi-volatile organd.cs and metals are not critical
for selecting the primary treatment processes. If this is, in
fact, the case, other treatment processes that were originally
screened out during the FS review because they were capable of
treating only VOCs, should Jbe evaluated, such as in-situ soil vapor
extraction. Numerous in-situ technologies are now available for
treatment of VOC contaminated soil that are far less costly than
incineration or LTTD. These technologies do not require excavation
of contaminated soils and, therefore, do not release VOCs into the
atmosphere. Releases or emissions of VOCs to the atmosphere caused
by excavation activities were not considered in the BSD or the FS.
(Brenan)
As clearly identified in the ROD the primary reason for treating
the raw waste and contaminated soils at the Site is to reduce the
toxicity and mobility of the contaminants contained therein and
thereby reduce their impacts on the groundwater. The ROD further
identifies volatile organic compounds (VOCs) as the contaminants of
primary concern because they contribute the greatest potential risk
to the groundwater. Therefore, for people nearby the Site who are
dependent-on the groundwater as a drinking water source, VOCs pose;
the greatest potential risk. Some semi-volatile organic compounds
and metals were found in the soils at the Site. However, because
of the differences in physical properties (e.g., solubility,
partitioning coefficient) and concentrations detected of these
compounds, they do not present the same risks to the groundwater as
VOCs do.
VOCs in the soil continue to be EPA's principle contaminant of
concern. Thermal desorption will be effective in treating and
removing VOCs and will also provide more effective ancillary
treatment of semi-volatile compounds. This is an additional
benefit of implementing thermal desorption.
As part of its evaluation of thermal desorption in the FS and the
BSD, EPA did consider the potential impacts that emissions could
have. EPA has concluded that through the use of available and
commonly used engineering controls and appropriate air monitoring
the risks posed by any fugitive emissions can be minimized. The
long-term benefits of removing the contaminated soils, raw wastes,
drums and/or containers outweigh any short-term risks posed by
emissions during excavation.
5. The analytical data from the site investigation and
characterization is limited and does not adequately segment areas
of soil contamination. Rather *-bf*n develop one overall site-wide
remedy, EPA should have considered remedies applicable to
particular areas of concern. (Brenan)
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EPA believes that the extensive sampling and monitoring performed
during the Remedial Investigation and Pre-Design field work have
adequately characterized the nature and extent of contamination at
the Site for the purposes of this BSD. The most recent sampling of
the soil at the Site during the Pre-Design field work in the fall
of 1991 identified the continued presence of high concentrations of
contaminants in and around the areas where dumping took place and
drums were stored or discarded. The types of contaminants found in
these areas were similar and consisted primarily of VOCs. Of the
technologies available to treat VOCs and achieve the certainty and
reliability needed, EPA identified thermal desorption as being the
most appropriate one for this Site. Please refer to EPA's General
Comments Response #1 for a further explanation of why EPA did not
select SVE for the Site or portions of the Site.
6. In proposing a change to the remedy, EPA should have
considered making changes to the groundwater remedy for several
reasons. (Brenan)
This proposed BSD addresses only the source control component of
the overall site remedy discussed in the ROD. At this time EPA
does not believe that changes to other components of the remedy are
warranted.
7. The JSSD acknowledges that EPA does not know the quantity and
kind -of contaminated soils needing remediation. EPA should
quantify the volumes and nature of contaminated material, if any.
At this point, while it is clear that incineration is
inappropriate, opposed by the public, and not in keeping with
current EPA thinking, there is not enough information available to
confirm that the LTTD alternative, as opposed to SVE or some
combination of innovative technologies, is the most cost-effective
alternative for remediation of on-site contaminated soils. (Brenan)
EPA will certainly agree that there are areas of the Site about
which EPA has more information than it does about others. However,
the information contained"in the Administrative Record supporting
the ROD and this proposed ESD demonstrates that EPA has in its
possession sufficient information to select the proposed cleanup
technology. Regardless of how much sampling is done up front there
will always be a level of uncertainty as to the extent and volume
of materials requiring treatment which will only be eliminated by
the actual performance and completion of the work. EPA believes
that it has reached the appropriate balance among the quantity of
data, time and money expended in gathering data, and the level of
certainty needed to make this change. Further study would only
delay addressing public health and environmental risks while
yielding only small incremental benefits, if any. Furthermore, as
discussed above and in the ESD, the data gathered clearly indicate
that thermal desorption is the most appropriate technology for the
Site, and that SVE would be less effective and protective of human
health and the environment at the Site.
8
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8. The ESD needs to clearly state that there are no federal or
Rhode Island cleanup standards for VOCa in soils. The cleanup
level of 2 ppm was selected to achieve an acceptable level of risk
as calculated in the 1986 risk assessment under the "premise" of
future residential land use for the site. The ESD should have
recognized that the land use of this property has not been and
presumably will not be for residential development, particularly
since the site has been used for industrial purposes including as
a tire recycling center for a number of years and continues to be
used for this purpose. Finally, the ROD allowed treated soils to
be backfilled so long as they passed the EP toxicity test. In
changing the remedy, the EPA should have recognized there is no
reason to excavate any soils at all that pass EP toxicity criteria.
(Brenan)
The commenter is correct that there are no national cleanup
standards for VOCs in the soil. The variability of conditions and
site-specific factors renders such an approach inappropriate. EPA
notes that the State of Rhode Island has recently promulgated draft
soil screening cleanup levels which do not apply at this Site as
they were not promulgated at the time the ROD was issued.
Similarly to the approach EPA takes at other Superfund sites to
determine soil cleanup levels, EPA used site-specific information
and assumptions to set cleanup levels for the Davis Liquid Waste
Site. The ROD clearly identifies that the soil cleanup levels were
determined based on the risks posed by the soil leaching
contaminants into the groundwater above allowable drinking water
standards. As part of the analysis in the RI and ROD EPA did
consider the current use of the Site and surrounding areas (e.g.,
portions covered with tires and other areas undeveloped) as well as
make a reasonable assumption for the future use of the Site and
surrounding areas (e.g., residential). The future use assumption
is still reasonable and applicable given such developments-as the
increased growth in the number of residences nearby the Site and
tires being removed from the Site by the property owner under a
State Superior Court Order. Therefore, the information already
provided in the ROD is sufficient to explain the basis for EPA's
establishment of the soil cleanup level and no further change to
the text of the ESD is warranted.
It appears that the commenters' last two statements misapprehend
the basis in the ROD for when EPA would apply the EP toxicity
criteria to soils at the .Site. The ROD identifies that soils at
the Site exceeding a concentration of 2 parts per million (ppm) for
total VOCs will be excavated and treated. Treatment of such soils
will continue until the levels are below the cleanup standard of 2
ppm. It is only after achieving this cleanup standard that soils
are to be tested for the EP toxicity criteria. The toxicity
testing was a means of determining what further treatment or
precautions were necessary, if any, for the final disposition of
the treated soils and wastes.
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The BSD modifies the testing by using the Toxicity Characteristic
Leaching Procedure (TCLP) in place of the EP toxicity criteria.
Those soils with concentrations that are below the TCLP regulatory
levels will be used to back fill 'excavated areas. The soils with
concentrations above TCLP regulatory levels will either be placed
in a RCRA Subtitle C landfill on-site or disposed of off-site at an
EPA approved facility.
9. The statements "A cleanup level of 5 parts per billion has
Jbeen established for benzene, trichloroethylene, and
tetrachloroethylene. EPA estimates that this target remediation
level can be achieved within 5 to 10 years." is inconsistent with
current government findings. The time frame postulated for cleanup
in the ESD, ROD, and FS of 5-10 years is not substantiated by any
modeling of the groundwater or contaminant fate and transport.
(Brenan)
The statements referenced above and made in the ESD regarding the
management of migration component were taken from the remedy as
originally described in the ROD. The information was included in
the ESD for background purposes only. This proposed ESD addresses
only the scurce control component of the overall site remedy
selected in the ROD. At this time EPA does not believe that
changes to other components of the remedy are warranted.
10. The proposed change from the ROD permitting off-site disposal
of treated soils requires an explanation from EPA. Off-site
disposal of such soils appears to contradict the original intention
of the FS and the ROD. (Brenan)
EPA's intent for including such language is to provide some
flexibility if, for example, there is only a very small volume of
treated material which does not pass the TCLP test. Under such
circumstances it may not be in the best interests of the public and
environment to construct an on-site RCRA Subtitle C landfill.
11. There are several technical differences between incineration
and LTTD that are not adequately addressed in the ESD.
Specifically: incineration oxidizes VOCs, SVOCs, and vaporizes some
metals while LTTD without an afterburner merely vaporizes VOCs, but
generally does not treat or reduce SVOC and metals contamination.
The ESD should explain the differences between incineration, LTTD
and SVE and explain why these differences do or do not
significantly change and/or fundamentally alter the overall remedy
with respect to cost and performance. (Brenan)
The text of the ESD and the supporting Administrative Record ,
adequately explain the difference between incineration and thermal
desorption. Please refer to EPA's General Comments Response #1 and
Technical Comments #4 for further explanation of why thermal
desorption is the technology of choice for the Site.
10
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12. EPA needs to clarify what IB meant by the following statements
in the ESD " The contaminants removed must be collected and treated
separately. In many instances this treatment occurs at a separate
off-site location." At a minimum, the ESD must identify the
contaminants, how they are going to be collected, and the location
of any off-site treatment. (Brenan)
The statements above were made in the context of explaining the
difference between the ultimate fate of VOCs when using
incineration versus thermal desorption. In incineration the high
temperatures cause the destruction of VOCs while in thermal
desorption the VOCs are physically driven out of the soil.
Depending upon the type of off-gas treatment on the thermal
desorption unit the VOCs can be destroyed through the use of an
afterburner or other type of oxidative unit or transferred to
another medium such as activated carbon and then treated and
disposed of either on-site or off-site {depending upon the
concentration of VOCs in the off-gas).
A number of different types of thermal desorption units (with an
equal number of means for off-gas control) may be applicable to
this Site. Each type of thermal desorption unit may have different
capabilities in terms of the type and size of drums or other
containerized wastes that can be treated. Because of this range of
capabilities as well as the possibility that new thermal desorpticn
technologies will be developed in the interim, EPA has not
specified in the ESD the particular type of thermal desorption unit
and off-gas treatment to be applied at the Site. EPA has also net
specified the off-site location for any wastes requiring further
treatment or disposal as this will be dependent on the capabilities
of thermal desorption technology selected. EPA believes that the
approach it is taking will provide the greatest flexibility during
the contractor selection process and allow for the selection of the
most appropriate thermal desorption vendor for the Site.
11
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ATTACHMENT //I
THERMAL DESORPT1ON COST ESTIMATE
QUANTITY UNITS® UNIT COST TOTAL COST
TASK/ITEMS
COMMENTS
I. DIRECT CAPITAL COSTS
1. ADVANCE SITEWORK
CONSTRUCT TD OPERATIONS AND SOIL STAGING AREA
CLEAR AREA 1 acre $5,000
LINER 21760 sq ft $1
BUILD BASE 2420 cu yds $8
2. MOBILIZE TD
TRANSPRT/SETUP 1 lump sum $350,000
UTILITIES 1 lump sum $30.000
3. EXCAVATION AND TRANSPORT OF SOIL
EXCAVATION
ENCLOSURE
MOVE ENCLOSURE
AIR MONITORING
AIR TREATMENT
4. SIEVING SOIL
SIEVING
TRANSPORT
ENCLOSURE
AIR MONITORING
AIR TREATMENT
5, TREATMENT OF SOILS WITH TD UNIT (1)
OPTIMIZATION STUDY 1 lump sum $125,000
TREATMENT 30450 tons $250
AIR MONITORING 200 days $200
$5,000
$21.760
$19,360
$46,140
$350,000
$30.000
$380.000
25000
5000
5
200
. 1
cuyds
sqft
move
days
lump sum
$15
$20
$33,000
$400
$75,000
$375,000
$100.000
$165,000
$80,000
$75.000
$795,000
200
200
2000
200
1
days
days
sqft
days
lump sum
$300
$500
$20
$400
$75,000
$60.000
$100,000
$40,000
$80.000
$75,000
$355.000
$125,000
$9,112,500
$40,000
$9,277,500
Size estimated for staging and stockpile area
Estimate 0,5 acres (or staging/operating area
Clean (III to be hauled In from off-site, placed
and compacted to a depth of 2' In cleared area
Vendor estimates ranged from $50K to $400K
Assumption Is that utilities will be run to site
for GWTP prior to this, so only minor work needed
Assume $15/yd due to Level C work
Assume steel framed tension structure (50'xlOO')
Structure has wheels but still 5 moves req'd
Assume four samples/day @ $100 each
Assume air from enclosure Is treated
with vapor phase carbon
Rental and maintenance of screen-all
Use of small rubber lire loader
Assume stee) framed tension structure
Assume four samples/day @ $100 each
Assume afr from enclosure Is treated
with vapor phase carbon
Based on cost range identified In EPA 540-F-93-04B
Assume two samples/day at $100 each
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TASK/ITEMS QUANTITY UNITS® UNIT COST
6.
7.
a.
TREATMENT OF BURIED DEBRIS (2)
TREATMENT 4050 tons $800
STOCKPILE AND TEST TREATED SOIL
VERIFICATION 250 samples $1,000
TRANSPORT 200 days $500
TREATMENT OF LARGE PARTICLES (3}
MATL HANDLING 70 days $350
STEAM CLEAN 190 days $300 '
SUBTOTAL, DIRECT CAPITAL COSTS
II.
INDIRECT CAPITAL COSTS
ENGINEERING 15 % of $14,525,140
CONTINGENCY 15 %of $14,525,140
TOTAL COST
$3,240.000
$3,240,000
$250.000
$100.000
$350.000
$24,500
$57,000
$81,500
$14.525.140
$2.178.771
$2.176,771
COMMENTS
Assume off-site Incineration of drums
and miscellaneous burled debris
Sample collection rate decreases with time
Assume separate small rubber tire loader
Assume treatable quantity generated every 3rd day
Assume that 10% of 36,450 cu yds requires steam
cleaning; therefore 3.645 cu yds cleaned at 1
cu yd/half hour
% consistent with those Identified In FS for Incineration
SUBTOTAL. INDIRECT CAPTIAL COSTS
$4.357.542
TOTAL ESTIMATED PRESENT WORTH COST
$16,882,682
Notes: (1) Assumed TO would be operating 24 hours per day, 7 days per week (w/approxlmately 20%
down time), assumed a unit throughput of 10 tons/hr for a total operational time of 200 days.
Estimated cost range In EPA 540- F- 93- 048 document is $200 to $300 per ton (avg. $250).
Did not Include bulking factor in volume estimate which could Increase volume by 20%
Density of soil assumed to be 120 Ibs/cu ft for conversion from cu yds to tons.
(2) Assumed that technology to be used for disposal of debris (i.e., drums, paint cans) would Involve
off-site incineration. Cost shown for ROD est volume Is based on disposing of a solid waste.
(3) Assumed that MOM groundwater treatment system would be In operation at the site and that waste
water generated during large particle decontamination would be treated In that facility.
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APPENDIX C
Comments Received Pursuant to the
Draft Explanation of Signficant Differences
for Changing the Method of Treating Contaminated Soils and Wastes
from On-site Incineration to On-Site Thermal Desorption
Davis Liquid Waste Superfund Site
Smithfield, Rhode Island
July 1996
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2000 Ore Lagan Squire
Philacdcna, PA 19103^993
215463-3000
Fas 215-563-S299 COL'SSELofti \ 7 L\w
Morgan, Lewis
sBockius UP
May 9, 1996
Neil Handler
Remedial Project Manager
U.S. EPA, Office of Site
Remediation and Restoration
JFK Federal Building (HBO)
Boston, Massachusetts 022Q3
Re: Comments Upon EPA's Proposed Explanation
of Significant Differences for the Davis Liquid
Superfand Site in Smithfield. Rhode Island
Dear Mr. Handler:
On April 9, 1996, EPA published a notice in the Providence
Journal Bulletin that it intended to issue an Explanation of
Significant Differences ("BSD") recommending'what it describes
as a significant change for the remedy previously selected in
the 1987 Record of Decision ("ROD") for the Davis Liquid '
Superfund Site in Smithfield, Rhode Island ("Davis Site"). The
ROD was based upon data and analyses in the Remedial
Investigation (RI) and Feasibility Study (FS) and their
appendices. In compliance with the newspaper notice, which we
did not learn about until substantially later, requiring that
public comments be postmarked no later than May 9, 1996, we, on
behalf of our client, a litigant, hereby provide the following
comments:
Washirjjjn Mew rent Los Angeles Miami Hamstxug Princeton London Bruss*3 Frankfut Tokyo
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Neil Handler
May 9, 1996
Page 2
Procedural Comments
P.I. EPA has failed to provide our client and others similarly
situated with adequate notice and -opportunity to comment on the
proposed SSD. The parties most interested in and most likely
to submit comments on EPA's proposed ESD are those named as
defendants and third-party defendants in the ongoing lawsuit
with regard to the Davis Site, United states of America v.
William M. Davis, et al. . (D.R.I. C.A. £90-0484-P). EPA's
failure to directly notify the litigants in that lawsuit is not
in compliance with the'spiriz or intent of § 117(d) of the
Comprehensive, Environmental, Restoration, Compensation and
Liability Act ("CERCLA") and unfairly penalized them by
providing inadequate time to prepare and submit comments on the
complex environmental issues presented by EPA's proposed ESD.
P. 2. EPA's failure to provide prompt notice and a reasonable
opportunity to comment to litigants who are currently required
to defend themselves at the Davis Site and who, therefore, are
at risk for remedial response costs incurred at the site is
especially troubling for those parties which were never
provided with notice or an opportunity to comment upon the
remedial action originally selected by EPA for the Davis Site
in the 1987 ROD.
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P.3. EPA's comment period provides inadequate time to review,
consider, and evaluate all of the documentation and data
identified in the proposed Administrative Record for the ESD.
This procedural defect is magnified because EPA ignored or
failed to timely respond to Freedom of Information Act ("FOIA")
requests submitted with regard to this site. To comment upon
the proposed change, a party must understand the proposed
remedy change in light of the original remedial decision. Even
the full 30 day comment period is inadequate to review and
analyze all of the information in the original Administrative
Record and the new proposed ESD Administrative Record.
P.4. The proposed Administrative Record for the ESD appears to
be incomplete. We understand that documentation which was
before the Agency and was instrumental in the Agency's decision
to issue an ESD has not yet been made available to the public
and is not included in the proposed Administrative Record for
the ESD. Those documents include the draft Scope of Work for
the soil remedy submitted by one party as well as related
documents and/or the deliverables such as the Preliminary
Remedial Design for the soil remedy.
P.5. Furthermore, the limited written comment period fails to
provide an adequate opportunity for public response to the
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Neil Handler
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proposed ESD. In light of the passage of nearly ten years
since the RI/FS was performed and the ROD remedy selected and
ZPA's acknowledgement that it is making a significant change to
the ROD remedy, and the restricted time available to provide
comments and pose questions to the Agency, pursuant to EPA's
OSWER Guidance on Preparing Superfund Decision Documents
9355.3-02, along with the proposed ESD EPA needs to provide the
public with the status of the remedial action, the costs
incurred to dare, the projected costs, and an explanation of
the appropriateness of the 1987 ROD remedy given the current
conditions at the site nearly 10 years later in 1996.
P. 6, The public is entitled to know EPA's best current
estimation as to the volumes of contaminated soils and/or waste
at the site which may have to be remediated, the extent and
current conditions of groundwater contamination including
whether that contamination has diminished or increased or any
longer poses a potential risk, and the projected time frame for
addressing both the soil and groundwater contamination. In
light of the eight year delay in the construction of the public
waterline, it is critical that EPA provide the public with this
information.
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ILLP
Neil Handler
May 9, 1996
Page 5
p. 7. The proposed ESD appears to be influenced by factors
other than technical and scientific concerns. We are concerned
that the proposed ESD is, at least in significant part, a
product of settlement negotiations and financial tradeoffs
between the United States and certain litigants rather than a
reasoned decision with respect to the costs and benefits of
technologies available in 1996. In this regard, there is
correspondence from July 24, 1995, which is not in the
Administrative Record but should be, which sets forth the
United States' positions on pump and treat, soil vapor
extraction, and low temperature thermal desorption.
P.8. Finally, we are providing the following general and
technical comments but are requesting an extension of the
comment period to allow all parties to supplement their
comments once they have had a fair opportunity to review and
consider all relevant data.
General Comments
G.l. We concur with EPA's decision to modify the ROD for the
Davis site as related to remediation of on-site soils and
further concur that current state-of-the-art remedial
technologies for volatile organic compounds (VOCs), the
contaminants of concern for the site, exist that are
substantially more cost effective than incineration. However,
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EPA's decision to review and significantly change the decisions
made by the ROD in 1987 in light of current remediation science
requires reevaluation of the conclusion drawn not only in the
ROD but also in the remedial investigation, and feasibility
study as well.
G.2. The ESD, as proposed, is too narrow in-focus and fails to
consider appropriate remedial technologies. For on-site soils
where VOCs are the constituents of concern, EPA's presumptive
remedy is soil vapor extraction (SVE) and this technology
should, at a minimum, have been evaluated. Furthermore, the
length of time since the RI/FS was conducted and the additional
data collected (particularly in the groundwater) when coupled
to recent governmental findings on the cost and ineffectiveness
of pump and treat remedies, suggest that EPA's groundwater
remedies also be revisited.
G.3. The ESD is flawed and its conclusions are in error
because the proposed ESD presents an inaccurate comparison of
the costs of incineration to the costs of its selected option,
low temperature thermal desorption. The use of unit costs, as
presented in the presumptive remedy guidance, is far too gross
an estimate to be used when millions of dollars are under
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Neil Handler
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Page 7
consideration. A cost estimate, at least as detailed as that
presented in the ROD and FS, needs to be prepared.
G.4. There is insufficient data upon which to base the
proposed BSD. The ESD, as well as the ROD, FS, and RI, all
recognize the imprecision of the site characterization data
which is being used as the basis for evaluating and selecting a
renedial alternative. These uncertainties are now compounded
by the age of most of the data. Moreover, as set forth below,
there are uncertainties as to the volumes of material to be
treated and further uncertainties as to various cost
projections and comparisons.
Technical Comments
T.I. Pg. 1, 53 states: "Because the adjustments to the remedy
selected in the ROD are significant but do not
fundamentally alter the overall remedy with respect to
scope, performance, or cost."
Comment. While we agree that the 1987 ROD should not be
implemented, the ESD contains inadequate documentation to
support its conclusion as to the similarity of scope,
performance, and cost of the proposed alternative remedy.
These individual items are discussed further in our comments to
the ESD.
T.2. Fg. l, 55 states: "Based on the information and data
generated since the issuance of the 29 September 1987 ROD,
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one portion of the remedy as described in the ROD has been
modified.11
Comment. The BSD does not describe nor summarize the
"information and data generated," nor does it indicate the
sources of this information. Without inclusion (or, at the
very least, a summary) of the specific data referenced, it is
not possible to evaluate the reasonableness of EPA's conclusion
that only one portion of the ROD should be modified. For
example, we understand that additional groundwater and
residential well sampling was conducted subsequent to the ROD
yet that information is not referenced in the ESD and it -is not
clear that it was considered in the development of the ESD.
Since the ROD is being revisited for the purpose of reviewing
the source control alternatives, all data, including data
i
relevant to groundwater and residential water, should be
reviewed to determine the appropriateness of changing the ROD
remedy.
T.3. Pg* 2, fll states: "EPA has selected on-site thermal
desorption as the means of treating contaminated soils and
waste at the site."
Comment. This statement is not entirely accurate. As
discussed in several of the comments below, the FS, ROD, and
even Pg. 9, 54 of the ESD clearly indicate that approximately
2500 yd3 of "waste11 estimated to still be on site are not
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treatable by low temperature thermal desorption (LTTD).
Significantly, the FS estimated off-site treatment of waste
material would cost $6.2 million or 48% of the total capital
costs of the LTTD option as evaluated in the FS. The ESD fails
to consider this cost from the FS. Therefore, the performance
and cost of LTTD have not been appropriately considered.
Moreover, the ESD, ROD, and FS do not define exactly what
constitutes this "waste,11 a serious omission considering the
proportion this cost contributes to the estimated project
costs.
T.4. Pg. 1, 52 discusses "The approximately 10-acre site..."
Comment. There appears to be a discrepancy between the site
size in the ROD and in the ESD. The ROD identifies the site as
being 15-acres. There is no explanation in the ESD as to which
5 acres have been eliminated for the purposes of the ESD or
why.
T.5. Pg. 3, Jl states: "The use of thermal ... will
significantly reduce the overall cost..."
Comment. Although we believe there are adequate soil remedies
much less costly than incineration, the conclusion that thermal
desorption will significantly reduce costs is not supported by
any data in the ESD and is, therefore, speculative.
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Neil Handler
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Page 10
T.6. Pg. 3, 32. states: "Because thermal desorption, like
incineration, removes contaminants through a theraal
process, the use of thermal desorption does not
fundamentally alter the remedy selected in the ROD."
Comment. EPA bases this argument on the fact that both
technologies are thermal processes. There are, however,
significant differences between incineration and LTTD'.
Incineration operates at considerably higher temperatures than
LTTD. Incineration destroys volatile organic compounds (VOCs)
as well as semivolatile organic compounds and volatilizes some
metal constituents. The LTTD process volatilizes the VOCs but
does not remove most senivolatile organic compounds or metals
from soils. Zven the VOCs volatilized by LTTD are destroyed in
the air stream only if an afterburner is employed. The use of
an afterburner in the proposed LTTD process is included in the
FS but is not mentioned in the ESD and, in fact, may not be
necessary.
By selecting the LTTD process, the EPA apparently has concluded
that semivolatile organics and metals are not critical for
selecting the primary treatment processes. If this is, in
fact, the case, other treatment processes that were originally
screened out during the FS review because they were capable of
treating only VOCs, should be evaluated, such as in-situ soil
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Neil Handler
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Page 11
vapor extraction (SVE). ' Indeed, SVE is EPA's primary
presumptive remedy at VOC contaainated sites.
Numerous in-situ technologies are now available for treatment
of VOC contaminated soil that are far less costly than
incineration or LTTD. Indeed, the EPA's Superfund Innovative
Technology Evaluation (SITE) program has provided the proving
ground for innovative in-situ technologies, including SVE, the
primary prescriptive remedy for VOC contaminated sites, that
may be applicable to this site. Furthermore, these
technologies do nor require excavation of contaminated soils
and, therefore, do not release VOCs into the atmosphere. The
release of VOCs during excavation and in soils handling is well
documented (Air/Superfund National Technical Guidance study
Series Estimation of Air Emissions from Cleanup Activities at
Superfund sites), and potentially can contribute to short-term
risks. Releases or emissions of VOCs to the atmosphere caused
by excavation activities were not considered in the ESD or the
FS.
T.7. Pg. 4, 53 states: "The Remedial Investigation...identified
extensive contamination of the soil, groundwater,
sediment, and surface water at the site."
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Neil Handler
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Comment. The analytical data from the site investigation and
characterization is limited and does not adequately segment
areas of soil contamination. The remedial investigation (RI)
completed in 1986 contains data that contamination in the soils
on site was localized in several discrete areas and identified
those areas by the nature of suspected materials disposed in
each. Rather than develop one overall site-wide remedy, EPA
should have considered remedies applicable to particular areas
of concern. AOC specific remedies such as stabilization and/or
capping (e.g., for metals), aay be appropriate and cost-
effective technologies for specific AOCs.
T.8. Pg. 4, 54 states: "Contaminants were found in both the
shallow overburden aquifer and the deeper bedrock
aquifer."
Comment. In proposing a change to the remedy, EPA should have
considered making changes to the groundwater remedy for several
reasons. The ROD remedy, a pump-and-treat system is based on
data gathered from pre-1986. The ROD and RI/FS indicated that
contaminants in groundwater decreased during the course of the
site investigations. Because more than 10 years have passed
from the time of the RI sampling on which the ROD was premised,
and since the contaminant concentrations and/or profiles will
have changed, there are serious questions about whether the
groundwater remedy selected in 1987 is cost-effective. The
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National Resource Council (NRC) and EPA have recognized the
serious technical limitations of pump-and-treat remedies,
especially in bedrock aquifers. The NRC criticized the
inability of many pump-and-treat systems to reach health-based
cleanup goals (NRC, Alternatives for Groundwater Cleanup,
1994). A survey of pump-and-treat remedies instituted at a
number of Superfund sites indicated that original FS operation
and maintenance (O&M) cose projections were generally greatly
exceeded by in-place systems because expected levels of cleanup
were not being achieved in the time frames projected, thus
requiring many more years of treatment. (Travis, Curtis C.,
and Doty, Carolyn B. 1990. "Can Contaminated Aquifers at
Superfund Sites Be Remediated?" Environmental Science and
Technology 24(10) : 1464-66.
T.9. Pg. 5, 55 states: 'Estimates for the number of tires
being stored at the property range from approximately 10
to 30 million. Approximately one-third of these tires are
being stored over areas which EPA believes may contain
contaminated soils."
Comment. The ESD acknowledges that EPA does-not know the
quantity and kind of contaminated soils needing remediation.
EPA should quantify the volumes and nature of the contaminated
material, if any. At this point, while it is clear that
incineration is inappropriate, opposed by the public, and not
in keeping with current EPA thinking, there is not enough
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Page 14
information available to confirm that the LTTD alternative, as
opposed to SVE or scae combination of innovative technologies,
is the most cost-effective alternative for remediation of on-
site contaminated soils.
T.10. Fg. 6, 53 states: "All soils and wastes with
volatile organic concentrations...would be excavated
to below the 2 ppm cleanup level...These
soils...below the EP toxicity levels...backfill
excavated areas. The soils with concentrations above
the EP toxicity levels would be placed in a RCRA
Subtitle C landfill on-site."
Comment. The ESD needs to clearly state that there are no
federal or Rhode Island cleanup standards for VOCs in soils.
The cleanup level of 2 ppm was selected to achieve an
acceptable level of risk as calculated in the 1986 risk
assessment under the "premise" of future residential land use
for the site. The ESD should have recognized that the land use
of this property has not been and presumably will not be for
residential development/ particularly since the site has been
used for industrial purposes including as a tire recycling
center for a number of years and continues to be used for this
purpose. Furthermore, the proposed construction of a Subtitle
C landfill on the Davis property is in direct conflict with
the ROD'S assumption that the property may still be used in the
future for residential development. The ESD also needs to
recognize that the ROD cleanup levels may be excessive in light
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of EPA1 s current policy which, as presented in the OSWER
Directive No. 9355.7-04 (Land Use in the CERCIA Remedy
Selection Process), is to develop remedial action objectives
based on a reasonably anticipated future use of the land for
commercial/industrial purposes. Finally, the ROD allowed
treated soils to be backfilled so long as they passed the EP
toxic ity test. In changing the remedy, the EPA should have
recognized there is no reason to excavate any soils at all that
pass EP toxicity criteria.
T.ll. Pg. 7, fll states: "A cleanup level of 5 parts per
billion has been established for benzene,
trichloroethylene, and tetrachloroethylene. EPA
estimates that this target remediation level can be
achieved within 5 to 10 years."
Comment. This statement, adopting EPA's old 1987 ROD estimate,
is inconsistent with current government findings. The time
frame postulated for cleanup in the ESD, ROD, and FS of 5-10
years is not substantiated by any modeling of the groundwater
or contaminant fate and transport. To continue to suggest that
5-10 years is the expected time frame in the absence of such
modeling or documentation is inappropriate in light of recent
GAO and NRC findings that pump-and-treat schemes installed at
Superfund sites have not accomplished the cleanup objectives •
established nor the time frame proposed. The time necessary to
achieve cleanup with pump-and-treat schemes has indeed been
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found to be substantially longer than estimated in the past/ if
it could be achieved at all, adding significantly to the costs
to remediate. This finding was particularly true for pump and
treat applied to fractured bedrock aquifers such as the bedrock
aquifer at this site. See "The Effectiveness of Groundwater
Pumping as a Restoration Technology" NTIS, May 1991 and
"Alternatives for Groundwater Cleanup," NRC, June 1994.
Furthermore, the nature of the VOC contaminants at issue (PCE,
TCE, DCE, vinyl chloride) suggest that even at the time of the
RI, natural degradation was taking place. This degradation
would continue to alter the nature and extent of groundwater
contamination; these changes need to be reviewed now prior to
continuing or finalizing a groundwater remedial plan. Finally,
the impact of the soil source control measures on the time to
remediate groundwater has not been adequately addressed and may
have significant bearing on the selection of an appropriate
groundwater remedy.
T.12. Pg. 7, 53 and 4 states that at the time of the ROD
n...the thermal desorption technology was still in
its infancy and there was a limited amount of
performance data available from full-scale operating
systems.11 "Since the FS, thermal desorption has been
widely used at Superfund sites to treat contaminated
soils similar to those found at the Site ... (and)
has shown this technology to be very effective in
removing volatile organic compounds ...' "The
Presumptive Remedy Guidance identifies that for sites
containing voc-contaminated soil if the material is
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to be excavated, (then) thermal desorption is the
preferred technology for treatment."
Comment. The ESD is deficient in that it fails to acknowledge
that other technologies, less costly that either incineration
or LTTD, have also been proven effective in the last ten years.
SVE technology (introduced in the FS report as "soil venting*
[see pages 3-5 of FS report]) was screened out in the FS as an
applicable technology because it was not fully proven and was
only capable of removing volatile compounds. However, as
discussed earlier, the proposed ESD selected LTTD as the
alternative technology over incineration implying that
semivolatiles and metals are not of primary concern. Based on
that same rationale, the feasibility of using SVE to treat
contaminated soils needs to be evaluated and compared to LTTD
using, at a minimum, the evaluation criteria presented in the
FS, namely, technical feasibility (performance, reliability,
implementability/constructability, and safety), institutional
requirements, public health and environmental impacts, and
costs. The Presumptive Remedy Guidance document, OSWER
Directive 9355.0-48FS cited by the ESD identifies SVE as the
remedy of choice for VOC-contaminat.ed soils and several
disposal areas on site may be suitable for this in situ
remedial application. The Seventh Edition of the Innovative
Treatment Technologies: Annual Status Report. 1995, indicates
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that SVE has been utilized at 130 sites since the publication
of the 1987 ROD and that SVE appears to be the source control
remedy of choice in EPA Region I being used at 15 of 22 sites
documented in the report. Indeed, the Administrative Record
for the ESD identifies a petition by another party proposing
that SVE be considered as an appropriate alternative to the
selected remedy but EPA has not yet provided a formal, public
response to this petition.
T.13. Pg. 8, 52 states: "With the increased usage of
thermal desorption since the FS, the cost of
implementing this technology has decreased. As
identified in the OSWER Guidance on Presumptive
Remedies, the average cost per ton for treatment
using thermal desorption is $250 and incineration is
$400. Thus the use of thermal desorption could
provide a savings of millions of dollars."
Comment. EPA's use in the ESD of unit costs from the
presumptive remedy guidance is inappropriate and insufficient
to document the reported savings of millions of dollars. The
ESD should provide a line-by-line cost estimate as was done in
the FS in order to properly attribute costs and/or savings.
According to the FS, $6.2 million of the $12.9 million in total
capital costs or 48% of the total capital cost for LTTD, were
allocated toward the off-site disposal of wastes that could not
be handled in the LTTD process. The cost that was allocated
toward the operation of the thermal desorption treatment unit
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was $1.8 million, only 14% of the total cost. Without a
detailed cost estimate that identifies quantities of treatable
soil and quantities of untreatable waste, it is not possible to
define any cost savings from the use of LTTD. Comparable
consideration of SVE would likely show even greater savings for
that remedy since the unit cost for SVE in the Presumptive
Remedy Guidance is $50/ton. See also, comments T.4 and T.7.
T.14. pg. 8, 55 states: "The soils with concentrations
above the TCLP regulatory levels will either be
placed in a RCRA Subtitle C landfill on-site or
disposed off^site at an EPA approved facility."
Comment. The proposed change from the ROD permitting off-site
disposal requires explanation from EPA. Off-site disposal of
such soils appears to contradict the original intention of the
FS and the ROD.
T.15. Pg. 8, fl6 states: "Since the ROD there has been some
additional sampling at the site that may indicate
whether the volume of material requiring treatment is
greater than that estimated in the ROD ..* Therefore,
until these tires are removed a more definitive
estimate of the volume of soil requiring treatment
cannot be made."
Comment. See comments T.8 and T.ll. It is premature for EPA
to select LTTD as a treatment alternative when in fact a
reasonable estimate of the quantity of soils requiring
treatment has not yet been determined. The ENSafe Review of
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Record of Decision incorporated as part of the proposed
Administrative Record for the ESD suggests that 38,000 to
50,000 cubic yards or more may need to be excavated. If
increased volumes of soils must be treated, other alternatives
• • „"".,-
(such as SVE or SVE in combination with LTTD) may well prove to
be' much more cost effective than LTTD alone.
T.16. Pg. 9, 52 states: "Thermal desorption is identified
as the preferred technology for treatment in the EPA
Presumptive Remedy Guidance for sites containing VOC-
contaminated soil requiring excavation."
Comment. At the outset, EPA's statement is improper because it
assumes that all contaminated soils must be excavated. There
is no evidence in the FS and the ROD to support that
assumption. Furthermore, in the Presumptive Remedies Guidance,
EPA has determined that SVE is the primary presumptive remedy
for VOC-contaminated soil present at CERCLA sites. Thermal
desorption and incineration are second and third respectively
on this prioritized list of presumptive remedies. Site data
suggests that SVE is a feasible remedy for much of the Davis
site.
Because the ESD's primary focus for soil remediation is to
/ ,
remove the VOCs, SVE technology should be considered and
evaluated for use at this site. At an average cost of $50/ton
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for SVE, as compared to $250/ton for LTTD (as presented in the
Presumptive Remedy Guidance), the overall cost savings and
reduced remediation time could be significant if SVE is
implemented.
SVE is an in-situ technology, "performed with minimum
disturbance to the soil and surrounding environment. In-situ
technologies are generally favored over technologies that
require soil excavation (referred to as ex-situ technologies)
because of the potential time and cost savings. The use of in-
situ technologies at the site was discussed in the FS (Pg. 3-
5), which states "in-situ treatment applications are
potentially preferable over on-site or off-site treatment
because excavation and corresponding site restoration
activities are not required and minimal disruption of hazardous
constituents occurs.11 Furthermore/ the short term -
environmental impacts of the remedy (such as significant air
emissions) are greater for excavation and treatment, than for
in-situ treatment.
T.17. pg. 9, 53 states: "Incineration heats VOCs to the
point where they are destroyed or decomposed while
thermal desorption uses a lower temperature
to...drive off and remove contaminants (physically)
from the media being treated.
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Comment. There are several technical differences between
incineration and LTTD that are not adequately addressed in the
BSD. Specifically: incineration oxidizes VOCs, SVOCs, and
vaporizes some metals while LTTD without an afterburner merely
vaporizes VOCs, but generally does not treat or reduce SVOC and
metals contamination. SVE also vaporizes VOCs. The BSD should
explain the differences between incineration, LTTD and SVE and
explain why these differences do or do not significantly change
and/or fundamentally alter the overall remedy with respect to
cost and performance.
T.18. ' Pg. 9, 53 states: "The contaminants removed must be
collected and treated separately. In many instances
this treatment occurs at a separate off-site
location."
Comment. EPA needs to clarify what is meant by this statement
in the ESD. At a minimum, the ESD must identify the
contaminants, how they'are going to be collected, and the
location of any off-site treatment.
T.19. Pg. 9, 5* states: "Thermal desorption will be unable
to treat any drums or large containerized wastes
encountered during excavation. Therefore, these
materials will either have to be shredded and treated
on-site or taken to an off-site location for
disposal.
Comment. See comment T.14. In addition, the ESD does not
specify the location of this newly proposed off-site location
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Lewis
Neil Handler
May 9, 1996
Page 23
or provide cost estimates to support the conclusion that the
cost of this newly proposed off-site disposal option will not
significantly affect the project's capital costs.
T.20. Pg. 9, 54 states: "Even with the additional costs of
having to dispose of this material, the cost savings
for employing thermal desorption over incineration
are nonetheless expected to be substantial."
Comment. This BSD statement is unsubstantiated. it is
premature to forecast a "substantial" cost savings when, in
fact, there is considerable uncertainty regarding (1) the
volume of materials at the site that are contaminated, (2) the
amount of waste requiring off-site disposal, (3) the location
of any off-site disposal facility, (4) the specifications or
location of any on-site landfill, and (5) the restrictions on
the types of waste that can be disposed in such a landfill.
T.21. Pg. 10, 51 states EPA has determined the revised
remedy is "cost effective1* and "uses permanent
solutions and alternative treatment technologies to
the maximum extent practicable for this site."
Comment. The ESD has not documented that LTTD is cost
effective given the uncertainties highlighted in previous
comments regarding waste quantities, disposal options, and the
extent of remaining contamination in soils and groundwater.
Moreover, alternative technology does not appear to be used to
the maximum extent practicable. According to the Presumptive
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Morgan. Lewis
> or
Neil Handler
'May 9, 1996
Page 24
Remedy Guidance, SVE, not LTTD, is the primary presumptive
remedy for VOC-contaminated soils, such as those present at the
site. The SVE technology is proven and can be combined with
other appropriate technologies such as capping, selective
source removal, and/or in-situ stabilization to achieve cleanup
levels established in the ROD.
Very truly yours,
Denis V. Brenan
7 ' • f.'"S""^
i •
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2000 Ora Login Sauira
PtMtipnto. PA 19103-6993
215-963-5000
rax: 215-963-5299
Morgan, Lewis
sBockius LLP
COUNSELORS \T LAW
RISUPERFUND SECTION
Denis V. Brenan
215-363-5407
May 31, 1996
Neil Handler
Remedial Project Manager
U.S. EPA - Office of Site Remediation and Restoration
J?K .Federal Building (HSO)
Boston, MA 02203
Re: Supplemental Comments Upon EPA's Proposed Explanation
of Significant Differences for the Davis Liquid Superfund
Site in Smithfield, Rhode Island
2ear Mr. Handler-.
As set forth in our original comments, on April 9, 1996, EPA
published a notice in the Providence Journal Bulletin that it
intended to issue an Explanation of Significant Differences
("SSD") recommending what it describes as a significant change
for the remedy previously selected in the 1987 Record of
Decision ("ROD") for the Davis Liquid Superfund Site in
Sitdthfield, Rhode Island ("Davis Site") . The ROD was based
upon data and analyses in the Remedial Investigation (RI) and
Feasibility Study (FS) and their appendices. On May 9, 1996,
we, on behalf of our client, a litigant, provided procedural,
general, and technical comments on the proposed BSD. Pursuant
to communications with Kathleen Woodward, Esq. of USEPA Region
I, we received permission to submit these supplemental comments
to be post-marked by May 30, 1996.
Supplemental Comment T.3.
As we noted on May 9, 1996, EPA's comment period provides
inadequate time to review, consider, and evaluate all of the
documentation and data identified in the original ROD
Administrative Record and the Proposed Administrative Record
for the BSD. In order to comment upon the proposed changes, a
party must understand the proposed remedy change in light of
the original remedial decision. At the time of our initial
comments, we intimated that the real rationale behind the ESD
appeared to be an undisclosed settlement between the United
States of America and one of the litigants in the case of the
United States v. William Davis, et al. in particular, United
P-n*J«pha WasMngnxi NewYort Los Angeles Miami Hwrnburg Prnestnn London Bruss«*i Frankfurt Tokyo
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Moran, Lewis
S
Neil Handler
May 31, 1996
Page 2
Technologies Corporation ("DTC"). Recent developments have
made i~ clear that there exists a settlement in principle
between UTC and the United States and that this settlement is
integrally related to and inseparable from the proposed remedy
change. Accordingly, EPA should immediately reveal the terms
and conditions of that settlement including buc not limited to
all che terms and conditions which affect the remedy to be
implemented at the Davis Site and should then provide an
adequate time to review, consider, and evaluate the settlement
terms in light of the remedy proposed in the ESD.
Supplemental Technical Comments
Supplemental Comment T.6.
As ncced in. our May 9, 1996 comments, the use of an af^er
burner in the proposed LTTD process is included in the FS but
is net mentioned in the ESD. Subsequent review of the
Trea-ability Study Report by ENSAFE," 1995, demonstrates that
there is no mention of the use of an afterburner in that
document either. Recognizing that the afterburner may not in
fact be necessary, it is important to note the apparent
deletion of the afterburner from the LTTD process makes the
LTTD process more similar to soil vapor extraction ("SVE") than
to incineration and underscores the importance of reconsidering
SYS as the ^resumptive and cost-effective remedy for soil
remediation at the Davis Site. In addition, the last sentence
of our May 9 comments stated that "release or omissions of VOCs
in the atmosphere -caused by excavation activities were not
cons idered in the ESD or the FS." Subsequent review of the
Treatability Study Report indicates that VOC loss was
experienced during ENSAFE's Treatability Study at significant
levels. Specifically, VOC concentrations fell by over 50%
after soil homogenization. Presumably this loss is the result
of fugitive emissions. A continuing VOC release to the
atmosphere of comparable scale is to be expected if soil is
excavated and handled in an ex situ process as is now
contemplated by the ESD. Control mechanisms' to handle such
fugitive emissions can be more readily and cost effectively
applied if SVE were the chosen technology'as opposed to LTTD.
Supplemental Comment T.8.
As we pointed out in comment G.2. on May 9, 199S, the ESD, as
proposed, is too narrow in focus and fails to consider
appropriate remedial technologies, especially in light of the
technological advances in the past ten years. The evaluation
and discussion of alternative technologies presented in the ROD
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Lewis
Neil Handler
May 31, 199€
Page 3
is severely outdated and needs to be revisited and modified to
include assessment of technologies currently available,
including but not limited to biodegradation, surface sealing,
grour.dwater barriers, horizontal air spargirig, and the like.
It seems incontestable that current technologies would help
reduce costs and accelerate the remedial project. These
comments are especially applicable to the grcundwater remedy at
the site. There are several alternatives to using a
conventional pump-and-treat system that may be more cost
effective. These include innovative technologies that treat
contaminated groundwater in place, such as air sparging or
technologies that enhance pump-and-treat system performance,
such as chemical and/or thermal enhancements. Technologies
that treat contaminated soil and groundwater simultaneously,
such as dual phase extraction, were not even evaluated in the
ROD cr the ESD. 3y failing to consider the use of these
current innovative technologies, EPA is improperly precluding
their use at the site simply because they were not available at
the time the FS was drafted more than ten (10) years ago. All
current technologies, including technology enhancements, need
to be evaluated and' compared to conventional pump-and-treat
systems at this time.
Since the May 9, 1996 comments, analyses of the soil,
groundwater, and residential well data presented in the Final
Pre-Design Engineering Report prepared for the tJ.S, Department
of the Army Corps, of Engineers by Woodward Clyde in 1993 has
been subject to further review. The results of this report
indicate a 10 fold to 100 fold reduction in total volatile
organic concentrations in the overburden aquifer that occurred
between 1985 and 1991. These results confirm that through
natural attenuation the levels of toxic constituents in the
overburden have been considerably decreased. Moreover, there
has undoubtedly been further significant decrease since the
last sampling events five years ago in 1991. Moreover, these
natural processes will continue to alter the nature and extent
of groundwater contamination. Accordingly, the effects of
natural attenuation should be reconsidered and the role of
volatilization and biodegradation should be reviewed prior to
embarking on groundwater remediation.
These comments are intended solely and exclusively to
supplement the comments previously made on May 9, 199S. They
are"not intended and should not be read to withdraw, diminish,
or revoke any comments made on May 9, 1996.
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Denis V. Brenan
DVB/mec
End.
cc: Kathleen Woodward, Esq.
.Lewis
iur
Neil Handler
May 31, 1996
Page 4
Very truly yours,
'
/ V
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AUSTIN"
1722 EYE STSEEX, N.W.
X, D.C. 2OO06
™,,- ~,
CH1C.AOO
- TELEPHONE 202: 73Q-8OOQ
LOS AXOEies TELEX 89-463
YORK FACSIMILE 2O2: 733-8711 TOKYO
isae
ncBCB
(202) 736-8547
- 9 596
May 8, 1996
m sOPgRFUNDSCTON
via Facsimile
and Federal Cypress
Mr. Neil Handler
Environmental Engineer
Waste Management Division
U.S. Environmental Protection Agency
JFK Federal Building
One Congress Street
Boston, MA 02203
Re; Explanation of Sigrrifirflnt Differences - Pavis TJquid Wasta
Soperfiinrf Site
Dear Mr. Handler:
I submit this comment letter on the Explanation of Significant Differences
("ESD") for the Davis Liquid Waste Site ("Site") on behalf of Browning-Ferris
Industries of Rhode Island, Inc. ("BFI-RI").
BFI-RI agrees that the soil component of the remedial action for the Site
should be changed from cm-site incineration. The ESD specifies, however, that the soil
contamination consists primarily of volatile organic compounds (" VOCs"). ESD at 4.
Yet, consistent with EPA guidance, soil vapor extraction ("SVE") would be the
preferred, cost-effective, and efficient remedy for removing VOCs from soils at this
Site, consistent with the national contingency plan. Sec Presumptive Remedies: Site
Characterization and Technology Selection For CERCLA Sites With Volatile Organic
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SIDLEY & AUSTIN WASHINGTON, D.C
Mr. Neil Handler
May 8, 1996
Page 2
Compounds in Soils (Sept. 1993). SVB is in place at numerous sites around the
country, including several in Region 1.
In short, EPA should revise the soil component of the remedial action for
the Davis Liquid Waste Site. However, it should be changed to SVE, not low
temperature thermal desorption.
Thank you for your consideration of these comments.
Sincerely,
Samuel B. Boxerman
/gra
cc: Michael Miller
Donna Kolar
0006508.01 M*y 8, 1996 (4:23pm)
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