United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EP AIROD/R05-91/176
September 1991
71 (
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oEPA
Superfund
Record of Decision:
Zanesville Well Field, OH
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50272-101
REPORT DOCUMENTATION 11. REPORTNO.
PAGE EPA/ROD/R05-91/176
I ~
:s. Redplent'8 ACC888Ion No.
... ThI8 8nd SubtI1Ie
SUPERFUND RECORD OF DECISION
Zanesville Well Field, OH
First Remedial Action - Final
7. Aulhor(e)
5. Report Date
09/30/91
6.
8. Performing Organization Rept. No.
8. Potrformlng Orgelnlzatlon Heme end Add....
10. ProjectlTeekJWork Unit No.
11. Contrect(C) or Grant(G) No.
(C)
1~ 8p0ne0rtng Orgenlzatlon Heme end Addre8a
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
(G)
1:s. Type of Report & PerIod Covered
Agency
800/000
14.
15. Supplementary No...
18. Abenct (UmIt: 200 _Ida)
The 100-acre Zanesville Well Field site is an active manufacturing and municipal well
site in Zanesville, Ohio. The site is composed of the 28-acre United Technologies
Automotive (UTA) facility and the 72-acre City of Zanesville Well Field. Land use in
the area is predominantly residential and industrial. The Muskingum River borders the
manufacturing area on the west and the well field on the east. From 1929 to the
present, the UTA property was used for various types of manufacturing activities.
During the early 1970's, a 10-foot wide, 75-foot deep onsite well was filled in by
using demolition material and approximately 121 steel drums, some of which contained
TCE. Additionally, TCE-based solvents were stored in a bulk storage tank adjacent to
the well, and other waste solvents were stored in drums located near storm sewer
basins. After EPA investigations in 1981 revealed VOC contamination in onsite ground
water, the use of three wells at the Zanesville Municipal Well Field was discontinued.
In 1983, approximately 145 tons of waste were removed from the filled in well by UTA
when the well was properly abandoned and sealed. Two of the three onsite wells are
currently part of a ground water interceptor system, in which extracted contaminated
water is discharged directly to the Muskingum River. This Record of Decision (ROD)
(See Attached Page)
17. Document Analyaia L D88cr1ptol'8
Record of Decision - Zanesville Well Field, OH
First Remedial Action - Final
Contaminated Media: soil" gw
Key Contaminants: VOCs (DCE, TCE), metals (arsenic, chromium, lead), other
inorganics
b. Identilier8/Open-Endeci Tenne
c. COSA T1 ReIdIGroup
18. Avlllebiity Stetement
tI. Security CI..e (Thle Report)
None
20. Security Cle.. (Thle Page)
Non~
21. No. 01 Peges
65
~ Price
(See ANSl-Z38.18)
See tMlrUclioM on ReWf8tl
27214-77
(Formerly NTlS-35)
Department 01 Commerce
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EPA/ROD/R05-91/176
Zanesville Well Field, OH
First Remedial Action - Final
Abstract (Continued)
addresses contaminated soil on and around the UTA facility, contaminated ground water
under and around the Zanesville Well Field and the UTA facility, and the sources of the
ground water contamination. The primary contaminants of concern affecting the soil and
ground water are VOCs including TCE and dichloroethylene; metals including arsenic,
chromium, and lead; and other inorganics.
The selected remedial action for this site includes treating approximately 36,000 cubic
yards of soil and source areas contaminated by VOCs using in-situ vapor extraction,
followed by activated carbon to control off-gases; regenerating the spent carbon from the
air stripping process; treating onsite 1,800 cubic yards of inorganic-contaminated soil
using soil washing; replacing the treated soil onsite; disposing of the concentrated
waste and treatment residuals offsite, with further treatment, if needed; pumping and
onsite treatment of contaminated ground water using air stripping; and implementing site
access restrictions to the UTA property, and to the interceptor wells, discharge pipes,
and treatment facilities located in the Zanesville City Well Field. The estimated
present worth cost for this remedial action is $2,972,450, which includes a present worth
O&M cost of $1,952,300.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific
risk-based levels for a cumulative excess lifetime
HI
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RECORD OF DECISION
SITE NAME AND LOCATION
Zanesville Well Field Site
Zanesville, Ohio
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for
the Zanesville Well Field Site in Zartesville, Ohio, chosen in
accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act of 1986 (SARA), and to
the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision is based on the
administrative record for this site.
The State of Ohio has been consulted and concurs with the selected
remedial action.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Decision (ROD), may present an imminent and
substantial endangerment to public health or the environment.
DESCRIPTION OF SELECTED REMEDY
The selected remedial action for the Zanesville Well Field Site
addresses. the principal threats posed by the conditions at the
site. The major components of the selected remedial action
include:
. Containment/capture of contaminated groundwater and
restoration of the aquifer to clean up levels through
groundwater pumping;
. Treatment of contaminated groundwater by air stripping;
~ Treatment of soil and source areas contaminated with
volatile organic compounds (VOCs) by in-situ vapor
extraction (ISVE);
. Treatment of soil contaminated with inorganic compounds
by soil washing; and
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Fencing of the United Technologies Automotive Inc. (UTA)
property and of the interceptor wells, discharge
pipes and treatment facilities located in the Zanesville
City Well Field.
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that are
applicable or relevant and appropriate to the remedial action
and is cost effective. This remedy utilizes permanent solutions and
alternative treatment or resource recovery technologies, to the
maximum extent pract1cable, and satisfies the statutory preference
for remedies that employ treatment that reduces toxicity, mobility,
or volume as a principal element. Because this re~edy will not
result in hazardous substances on-site above health-based levels,
the five-year review will not apply to this action.
~~
Date
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I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
x.
XI.
XII.
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
ZANESVILLE WELL FIELD SITE
ZANESVILLE, OHIO
TABLE OF CONTENTS
SECTION
PAGE
Site Name, Location, and
Description....................l
site History and Enforcement Activities................ 1
community Relations History........................... 3
scope and Role of Remedial Activities ................. 3
summary of Site
Characteristics ....................... 3
Summary of Site
Risks. . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . . .. 6
Remedial Action
Obj ecti ves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Descriptions of
Alternatives...........................13
Summary of the comparative Analysis of Alternatives....29
The Selected Remedy ...................................38
statutory Determinations...............................40
Documentation of significant Changes ..................42
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I.
SITE NAME, LOCATION AND DESCRIPTION
The Zanesville Well Field Site includes the united Technologies
Automotive, Inc. (UTA) facility and the City of Zanesville, Ohio
Well Field (Figure 1). The 28 acre UTA facility is located
between Linden Avenue and the Muskingum River within the City of
Zanesville. There is residential housing on the west side of .
Linden Avenue and industrial use to the south of the UTA
facility. The 72-acre well field lies across the River from the
UTA facility, and the City currently pumps 5.5 to 6.0 million
gallons per day (mgd) of groundwater from ten unaffected supply
wells in the field. Three of the City's wells no longer supply
water to the system because they have become contaminated. Two
of these wells (W-6,W-12) are currently being used as part of the
groundwater interceptor system. These wells directly discharge
the contaminated water to the Muskingum River. A groundwater
interceptor well system on the west side of the Muskingum River
(UTA's property) currently pumps about 870 gallons per minute
(gpm) and discharges treated water to the Muskingum River.
II.
SITE HISTORY AND ENFORCEMENT ACTIVITIES
There is a long history of manufacturing at the UTA site. Prior
to 1929, a hand dug well ten feet in diameter and forty feet deep
was instal.1ed on the property. The well was extended an
additional 35 feet. The well was located approximately 150 feet
west of the bank of the Muskingum River.
The well was filled in the early 1970s. Rubble from the
demolition of the well pump house and an estimated 121 steel
drums were used to fill in the well. Some of these drums
contained trichloroethylene (TCE) based solvents. TCE is a
chemical commonly used as a solvent and as feed stock in
pharmaceuticals. It is a possible carcinogen. Approximately 145
tons of waste from the well including drums, drum fragments, soil
and bricks were removed by UTA when the well was properly
abandoned (sealed) and closed in 1983.
In addition to the abandoned well, other suspected sources of
contamination at the facility include a former bulk solvent
storage tank located adjacent to the well and two large storm
sewer basins. The basins are referred to as the North and South
Basins. An open area that was used to store drums containing
waste solvents may also have contributed to contamination at the
UTA facility. This storage area is located northwest of the
storm sewer basins (see Figure 1 A).
In 1981, U.S. EPA detected contamination at the Zanesville
Municipal Well Field. During 1981-1982, the u.S. EPA andOEPA
conducted additional sampling in the southern portion of the well
field. Three wells were found to be contaminated with TCE and
dichloroethylene (DCE) , both of which are volatile organic
compounds (VOCs). VOCs have a tendency to evaporate when exposed
to air. Due to this tendency, VOCs evaporate more readily in
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2
surface water than in groundwater. When present in drinking
water, VOCs may pose a potential threat to human health. Since
1983 the city has been performing sampling ahd analysis of the
contaminated wells and plant tap. No additional wells have been
found to be contaminated, and the plant tap has never shown
detectable levels of .VOCs since 1981. .
.The City of Zanesville conducted an investigation of the UTA
facility and the municipal well field to determine the extent and
source of contamination. In 1983, based on the information
gathered about contamination present at its property, UTA
constructed a pump and treat system to deal with contaminated
groundwater. Pumping the groundwater removes contaminants from
the aquifer and contains or delays further spreading of the
contaminants into the well field. The pump and treat system works
by pumping groundwater from groundwater wells to the surface and
treating it by forcing air into the water thus allowing the
contaminants to evaporate. VOC contaminants like TCE and DCE
evaporate readily when exposed to air. This form of treatment is
called air stripping. Once the water has been treated with. this.
system, it is discharged into the river in compliance with the
State of Ohio discharge standards, which meet the substantive
requirements for an NPDES wastewater discharge permit. .
On September 8, 1983, the Zanesville Municipal Well Field site
was listed on the National Priorities List (NPL). The NPL is a
list of top priority hazardous waste sites in the country that
are eligible for investigation and clean up under the Superfund
program. U.s. EPA has that determined UTA is a potentially
responsible party (PRP) at the Zanesville Site. On August 3,
1988, a Consent Agreement was signed between UTA, OEPA and u.S.
EPA whereby UTA agreed to conduct a Remedial Investigation and
Feasibility Study (RIfFS) at the site. Prior to the Consent
Agreement, environmental investigation activities at the UTA
facility were supervised by OEPA.
In January 1989, UTA submitted a summary of the firm's previous
environmental investigations at the site to U.S. EPA and OEPA.
This report was called the Phase I Remedial Investigation (RI).
Findings of these investigations indicated that concentrations of
groundwater contamination appeared on the average to be
decreasing. On January 15, 1990, UTA submitted the Phase II RI
Report. U.S. EPA and OEPA approved the report on September 24,
1990. The Final FS was placed in the public information
repository for public viewing on July 29, 1991.
III. COMMUNITY RELATIONS HISTORY
Environmental issues and concerns were identified based upon
information from EPA files, interviews and public hearings
conducted in Zanesville.
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On June 26 and 27, 1990, U.S. EPA interviewed four individuals,
six local officials, three civic leaders and two environmental
organization leaders, who were residents of Zanesville.
On February 28, 1991, a public availability session was held to
answer questions regarding the RI study. Following completion of
the FS, the U.S. EPA published a notice of the Proposed Plan for
remedial action in a local newspaper on August 9. 1991. The
RIfFS Report, the Proposed Plan for remedial action and the
Administrative Record have been placed in an Information
Repository located at the Muskingum County Public Library.
Consistent with Section 113 of CERCLA, the Administrative Record
includes all documents such as the work plan, data analysis,
public comments, transcripts, and other relevant information used
in developing remedial alternatives for the site.
To encourage public participation in the remedy selection process
consistent with Section 117 of CERCLA, the U.S. EPA set a 30 day
public comment period from August 10, 1991 through September 9,
1991 for the Proposed Plan. The comment period was later
extended until September 16, 1991. A formal public hearing was
held on August 15, 1991 to accept public comments. Interested
parties provided comments on the alternatives presented in the
Proposed Plan and elaborated upon the FS. The remedy for the
Zanesville Well Field Site described herein was selected after a
detailed review of the public comments received. The attached
Re~ponsiveness Summary addresses those public comments received.
IV. SCOPE AND ROLE OF THE RESPONSE ACTION
The scope of the final response action addresses: contaminated
groundwater under and around the Zanesville Well Field and the
UTA facility, the sources of the groundwater contamination and
contaminated soils on and around the UTA facility.
The role of this final response action will be to permanently
reduce the risk to human health and the environment posed by
contamination at the site. This would be performed by extracting
and treating groundwater, remediating soils and any sources to
prevent further contaminant migration to groundwater and to
prevent exposure of humans to soil contaminants.
v. SUMMARY OF SITE CHARACTERISTICS
The quantitative extent and magnitude of contamination was
determined as a result of the Phase II Remedial Investigation
(RI) conducted at the site during the summer of 1989. The Phase
II RI and the FS were performed by Geraghty & Miller on behalf of
United Technologies Automotive, Inc. (UTA), a Potentially
Responsible Party (PRP). Several environmental matrices
(groundwater, soils, sediments) were sampled and analyzed for a
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4
wide variety of parameters. The results of these investigations
are presented in the Phase II RI, which was approved by U.S. EPA
and OEPA on September 24, 1990. UTA has also submitted a Phase I
RI. The Phase I RI is a compilation of previous studies and
reports UTA had performed prior to the Consent Agreement. There
was a lack of quality assurance and quality control documentation
for the Phase I data, thus a Phase II RI was required. The data
in the Phase I RI can be used to show general trends of changes
in concentrations of contaminants in the groundwater. The data
in the Phase I RI is also useful in giving an historical
perspective to the site.
Groundwater Analytical Results
Groundwater samples were collected from monitoring wells on the
UTA property and from monitoring wells and selected production
wells in the municipal well field. TCE concentrations in samples
from the shallow portion of the aquifer ranged from below the
detection limit up to 3,100 parts per billion (ppb) (Figure 2).
DCE concentrations were as high as 770 ppb (Figure 3). The
highest concentrations of TCE .and DCE were detected in monitoring
wells. located in the vicinity of the former dug well and the.
former bulk storage tank. Lower levels of TCE and DCE were
detected in the vicinity of the former drum storage area. In the
intermediate zone of the aquifer the highest concentrations of
TCE and DCE (1,300 ppb and 340 ppb respectively) were also in the
vicinity of the former dug well. In the deep portion of the
aquifer, no TCE or DCE was detected. In addition, no VOCs were
detected in the groundwater from the bedrock. The dimensions of
the plume of TCE was approximately 1600 by 1200 feet where as the
plume of DCE was approximately 1600 by 400 feet.
Groundwater monitoring wells and production wells within the
Zanesville well field were also sampled. Concentrations of TCE
ranged from 5 ppb to 1400 ppb, and concentrations of DCE ranged
from below the detection limit to 65 ppb. Groundwater samples at
the site were also analyzed for metals and cyanide. Although
there were metals present in the groundwater, the concentrations
and sporadic locations indicated that there was not a definable
plume of contamination. Many metals naturally occur in
groundwater and their presence may not be indicators of site
related groundwater contamination.
Although it appears that the plume of contamination is contained,
the plume of contamination could potentially migrate to the
northern portion of the City of Zanesville Well Field. The
population that could be affected are the residents living in and
around Zanesville currently using municipal water. and/or a
resident drinking water from a future well within the plume of
contamination. .
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5
In addition, although the VOCs have never been detected in the
Muskingum River, the contamination plume could potentially
migrate to the Muskingum River. '
Soil Boring Analytical Results
There was no TCE, DCE or inorganic (metal) contamination detected
in the soil samples from within the Zanesville Well Field area.
On UTA property, only those borings which were located near the
former dug well, the former bulk solvent storage tank and the
former drum storage area, exhibited significant levels of VOCs.
The soil gas survey also showed areas of high TCE and DCE
concentrations near the Southeast side of the main manufacturing
building, which is likely associated with the clay tile system.
The TCE concentration was as high as 170,000 ppb and the DCE
level was 16,000 ppb. The highest concentrations were
encountered between 0 and 6 feet below the land surface, which
were located in the area of the former dug' well, bulk storage
tank and north catch basin. Only a few samples were collected
between ,6 and 24 feet in depth which resulted in data gaps. In
deeper borings subsequent samples were only taken at deptps of
approximately 24 to 26 feet below the land surface. Therefore,
the lowest depth of elevated concentrations are not known. In
the vicinity of the former drum storage area the highest levels
of TCE and DCE were 4,500 ppb and 1,900 ppb respectively. The
highest levels were found within the upper 8 feet, however this
area also has some data gaps. The total estimated volume of VOC
contaminated soils is 36,000 cubic yards. VOCs are very mobile
in soils and the soils could be a source of VOCs for groundwater.
The FS also concluded that a currently undetermined source of
VOCs may be contributing VOC contamination to the groundwater.
Results of analyses of soil samples for inorganic parameters
indicate that aluminum, antimony, barium, cadmium, chromium,
cobalt, copper, lead, magnesium, manganese, mercury, vanadium and
zinc were found significantly above background samples in at
least one soil sample from the UTA property. The inorganic
parameters substantively above background were generally found at
a depth of up to 12 feet, however many data gaps exist. The
former drum storage area, the vicinity of the former dug well and
the north catch basin showed elevated levels of inorganic
parameters. The total estimated volume of inorganic contaminated
soil is 1800 cubic yards.
The population that could be exposed to soils contaminated with
VOC or inorganic contamination include the workers of the UTA
facility and any future residents that live on the site.
Muskinqum River Water and Sediment Sampling
Surface water and sediment samples were collected and analyzed.
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6
No trends in the data were detected and neither TCE or DCE were
detected in any of the water or sediment samples. As a
consequence of computer modeling of groundwater flow conditions,
desorption of VOCs from riverbed sediments to groundwater was
assumed to occur at the site in order for the model to
approximately simulate observed site conditions. Additional
information will be collected during the pre-design phase of this
remedial action to determine if river bed sediments are adding
VOCs to the groundwater. This additional information may include
additional monitoring wells in the well field, determination of
actual pumping rates of the municipal wells and/or re-sampling of
riverbed sediments.
VI. SUMMARY OF SITE RISKS
A quantitative risk assessment that examined present and future
potential human health and environmental risk posed by current.
site conditions was presented in chapter 5.0 of the Phase II RI
r~ort. .
HUMAN HEALTH RISK.
Two organic compounds and twelve inorganic compounds were
identified as potential chemicals of concern in various
contaminated media. They are:
Orqanic Chemicals of Concern
. Trichloroethylene
. 1,2 - Dichloroethylene (cis- and trans- isomers)
Inorqanic Chemicals of Concern
Arsenic
Barium
Cadmium
Chromium
Copper
Cyanide
Iron
Lead
Manganese
Mercury.
Silver
Zinc
In order for a risk to exist, a pathway from the chemicals of
concern to a potential receptor must be present.
Two Human Health Risk exposure scenarios were developed: 1)
worker exposure scenario to air releases from groundwater.
treatment, soil and non-potable groundwater; and 2) residential
exposure scenario to drinking water, showering, soil, fish
ingestion and swimming. Non-carcinogenic and carcinogenic risks
.were evaluated from calculated exposures to the chemicals of
concern in various media. Standard exposure assumptions were
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used, as specified in the u.s. EPA Risk Assessment Guidance for
Superfund(1989).
Currently, the site land use is industrial with workers being the
population at risk due to potential exposure to contaminated
soil, and workers and local residents at risk due to potential
exposure to VOC vapors. The residents currently using Zanesville
municipal water are also at risk due to potential exposure to
contaminated groundwater, if the plume of contamination migrates
northward and contaminates the municipal water supply.
The goal of the risk assessment was
health and the environment posed by
factors (CPFs) are used to quantify
humans. Reference Doses (RfDs) are
noncarcinogenic risks to humans.
to assess the risks to human
the site. Cancer potency
the carcinogenic risks to
used to quantify the
Cancer potency factors (CPFs) have been developed by EPA's
carcinogenic Assessment Group for estimating excess lifetime
cancer risks associated with exposure to potentially carcinogenic
chemicals. CPFs, which are expressed in units of (mg /kg-day) -1 ,
are multiplied by the estimated intake of a potential carcinogen,
in mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake
level. The term "upper bound" reflects the conservative estimate
of the risks calculated from the CPF. Use of this approach makes
underestimation of the actual cancer risk highly unlikely.
Cancer potency factors are derived from the results of human
epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been
applied.
Reference doses (RfDs) have been developed by EPA for indicating
the potential for adverse health effects from exposure to
chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units of mg/kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals.
Estimated intakes of chemicals from environmental media (e.g.,
the amount of a chemical ingested from contaminated drinking
water) can be compared to the RfD. RfDs are derived from human
epidemiological studies or animal studies to which uncertainty
factors have been applied (e.g., to account for the use of animal
data to predict effects upon humans). These uncertainty factors
help ensure that the RfDs will not underestimate the potential
for adverse noncarcinogenic effects to occur.
The residential exposure scenario was considered appropriate
because of the close proximity of the residential land use to the
UTA facility and the desirability of potential future residential
building on the UTA bluff setting. Residential housing in this
area commonly have basements. During construction, soil from
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8
depth could be brought to the surface resulting in an exposure to
residents. It would be unlikely, however, that residents would
be exposed to soil deeper than 15 feet under normal
circumstances.
The results of the baseline risk assessment (i.e., risk that will
remain if no action was taken at the site) determined that there
is an unacceptable risk at the Zanesville Well Field Site. u.S.
EPA has determined an acceptable range of risk for carcinogens to
be 104 to 10~ excess lifetime cancer risk (ELCR) and a Hazard
Index less than 1 for non-carcinogens. u.S. EPA guidance risk
criteria were exceeded at the site when a residential exposure
was considered. The risk criteria were exceeded for carcinogens
using the mean and maximum site concentrations, and for non-
carcinogens, using the maximum detected site concentrations
(i.e., the soil hot spots). The maximum contaminant
concentrations for soils and. groundwater were determined to be
the reasonable exposure scenario. .
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare or the environment.
The total non-carcinogenic and carcinogenic site risk under these
different scenarios are as follows:
Risk Scenario
Hazard Index
Max Mean
10 0.04
50 0.3
50 0.3
Excess Cancer
Residential Exposure
30 years.
Max Mean
2X10.s 1X10~
1X10.3 2X10-s
3X10-3 4X10-s
Worker Exposure
Residential Exposure
70 years
ENVIRONMENTAL RISKS
A preliminary ecological assessment was performed at the site.
The only identified potential environmental exposure pathway to
contamination at the site is through groundwater discharge to the
Muskingum River with aquatic life being the receptors. TCE and
DCE concentrations in the River were calculated in the risk
assessment. The estimated concentrations to which aquatic life
could be exposed were well below both Federal and state of Ohio
standards for protection of aquatic life. Therefore, the risk
assessment concluded that TCE and DCE pose a minimal potential
hazard to aquatic life in the River.
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A preliminary biological survey conducted at the UTA site
concluded that it has little potential to support a terrestrial
or semi-aquatic community. It was therefore concluded that the
chemicals detected did not likely pose a hazard to the existing
terrestrial environment.
VII.
REMEDIAL ACTION OBJECTIVES
The remedial action objectives are the media-specific goals that
must be achieved to protect human health and the environment.
'Principal threats are those source materials considered to be
highly toxic or highly mobile that generally cannot be reliably
controlled and that present a significant risk to human health or
the environment. They include liquids, highly mobile materials
(e.g., solvents) or high concentrations of toxic compounds
(inorganics). The principal threats to b~ addressed at this site
are the sources of groundwater contamination, soils, and the clay
tile system. The source of the contamination is a principle
threat because it continues to contaminate the groundwater. The
soils are principal threats at this site because of potential
direct contact with the soils,' and the soils' impact on the
groundwater. The clay tile system is a principal threat because
of the potential impact on the soils, the groundwater, and the
potential for direct contact.
There are four response objectives that have been developed in
order to remediate the principal threats. The four response
objectives are:
1)
Contain/capture contaminated groundwater and restore the
aquifer by remediating contaminated groundwater to
achieve groundwater clean up levels throughout the
contamination plume.
Contain/capture contaminated Groundwater
U.s. EPA proposes to contain/capture the contaminated groundwater
through a network of interceptor wells installed within the plume
of contamination. They will be utilized to pump groundwater in
order to force a hydraulic barrier. This hydraulic barrier, if
designed correctly, will be able to prevent the further spread of
the plume of contamination. These same interceptor wells can be
used to capture the contaminated groundwater by pumping it from
the aquifer to the surface for treatment.
Restoration of Aquifer
The National Oil and Hazardous Substance Contingency Plan (NCP)
states that the U~S. EPA groundwater policy is to rapidly restore
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10
aquifers (when practicable), that are currently being used as a
drinking water source. The NCP gives a range of 1 to 5 years for
very rapid restoration, to relatively extended restoration of
perhaps several decades. u.s. EPA's goal for the Zanesville Well
Field Site is rapid aquifer restoration.
A limiting factor in clean up time is likely to be the additional
contribution of VOCs from the source, in addition to the
limitations of groundwater pumping. Source reduction will reduce
loading of VOCs into the groundwater. It is believed reduced
loading of VOCs will shorten the time frame for aquifer
restoration.
There are many physical parameters, unknowns, and heterogeneities
that may extend the clean up time frame. It is important to note
that a failure to restore the aquifer within the NCP rapid
restoration goal time frame is not a failure of the remedy. The
FS states that source control, such as in-situ vapor extraction
(ISVE), can be used to significantly shorten the aquifer
restoration time frame~ Additional techniques such as pulse
pumping and additional interceptor wells and/or higher capacity
pumps in the heart of the plume may also shorten the restoration
time frame. .
Groundwater Clean Up Levels
Maximum Concentration Limits (MCLs) are promulgated standards for
chemical constituents in tap water that are considered protective
of public drinking water. Health based cleanup standards take
into account the adverse effect a chemical can have on human
health. Carcinogenic (cancer-related) and non-carcinogenic
effects from the chemicals of concern in groundwater were
evaluated in the Phase II RI Risk Assessment. TCE and arsenic
were the only carcinogens detected in the groundwater. TCE was
detected at a concentration above the MCL of 5 ppb. Arsenic was
only detected below the MCL of 50 ppb. Therefore it was not
further considered. TCE has both carcinogenic and non-
carcinogenic characteristics. The non-carcinogenic chemicals of
concern found above MCLs are TCE, cis-DCE, trans-DCE, iron and
manganese. The MCL for cis-DCE is 70 ppb and for trans-DCE it is
100 ppb. Iron and manganese exceeded secondary MCLs, which are
standards for chemical constituents that affect taste, odor and
the appearance of the water. A new MCL for lead of 5 ppb is
being proposed. Two monitoring wells on the UTA property
exhibited levels of lead in groundwater above the proposed MCL.
For the Zanesville Site, groundwater cleanup levels for TCE, cis-
DCE and trans-DCE are 5 ppb, 70 ppb and 100 ppb respectively.
After groundwater remediation is complete, all MCLs and health
based cleanup standards will be met for all of the chemicals of
concern in groundwater. The health criteria of a cumulative
excess lifetime .cancer risk (ELCR) for groundwater within the
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acceptable risk range of 1x104 to 1X10~, and a cumulative Hazard
Index for groundwater less than 1, will be m~t after remediation
is complete.
- 2)
Remediate source areas or prevent migration from source
areas which cause groundwater to be contaminated in
concentrations that exceed ARARS or risk-based levels.
Source Remediation
The groundwater being pumped .by the four UTA interceptor wells
has shown a general declining trend in the concentrations of
VOCs. Concentrations of VOCs in interceptor well 1-4 have not
decreased as readily as in interceptor wells 1-1, 1-2 and 1-3.
Interceptor well 1-4 was installed three years after the other
three interceptor wells. Interceptor well 1-4, which is located-
between the plant and the other three interceptor wells and
furthest from the river, removes on the average 1.7 pounds per
day of VOCs from groundwater. Also, the soil vapor extraction
system located at 1-4 has consistently removed between 0.3 to 1
pound per day of VOC vapors. The Feasibility study concluded
that a currently undetermined source of VOCs may be contributing
to the concentrations observed in interceptor well 1-4. It is
suspected that the aquifer, or the saturated zone, and the
unsaturated zone above the water table may be acting as a source
for VOCs in this area. During Remedial Design additional studies
will be performed to determine the location and extent of the
source. The soil cleanup alternative will be adjusted as
necessary to include this possible source.
3)
Remediatesoils
groundwater, or
with soils that
excess of MCLs,
to prevent contaminant migration to
direct contact, ingestion, or inhalation
contain contaminant concentrations in
ARARs, or risk-based levels.
Soil Clean up Levels Based on Leaching
There is a potential for contaminated soils to leach constituents
into groundwater in concentrations that exceed the groundwater
clean up levels. Therefore, the clean up level for soils, based
on leaching, will be the minimum soil concentration that will not
leach constituents into groundwater above their respective MCLs.
Given a known groundwater clean up level, the groundwater
concentration of a given constituent which desorbs from the soil
is used to back-calculate the allowable soil concentration. The
VOCs are the constituents most likely to migrate through the
soils and affect the groundwater. Using the conservative Summers
model, the calculated values for soil clean up levels protective
of groundwater for TCE, cis- DCE, and trans- DCE are 6.3 ppb,
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34.3 ppb and 59.0 ppb respectively. These values were calculated
using limited available site specific data and typical text book
values for many of the required equation parameters. Additional
site specific data will be collected during the pre-design to
better determine the clean up values. The additional data will
include: total organic carbon (TOC), Kd, soil moisture and other
required soil parameters for all the soil types at the site.
After soil values are determined, the Summers model or the more
sophisticated Multi-Med model will be used to calculate the
actual clean up concentrations.
soil Clean up Levels Based on direct contact,inqestion, or
inhalation.
The residential exposure scenario was considered appropriate
because of site specific conditions, including the close
proximity of. the residential land use to the site, the
desirability of the UTA bluff setting, and current U.S. EPA
guidance. A future residential scenario was used to develop .the
clean up levels. Residential housing in this area commonly. have
basements. During construction, soil from depth could be brought
to the surface resulting in an exposure to residents. Under this
scenario, contaminated soil will be remediated to a maximum depth
of approximately 15 feet. It would be unlikely that residents
will be exposed to soil deeper than 15 feet under normal
circumstances.
The soil clean up levels for the inorganic chemicals of concern
represent concentrations which yield a cumulative hazard index
less than 1, and the cumulative excess lifetime cancer risk
(ELCR) less than 1x10~. Table 1 summarizes the calculated soil
concentrations that achieve the soil clean up levels. The actual
soil concentrations of the chemicals of concern may vary during
remedy implementation due to heterogeneity in the soil. If the
calculated clean up concentrations for soils cannot be met, U.S.
EPA may allow new clean up concentrations to be calculated for
individual chemicals as long as the overall soil clean up level
is met. For example, after soil remediation samples indicate
that the soil concentration of the inorganic chemicals of concern
yield a cumulative hazard index less than 1, a cumulative ELCR
less than lxlO~, and the VOC soil concentrations will not
contribute additional VOCs to groundwater above MCLs, the soil
remediation should be considered complete.
4)
Prevent inhalation of air which contains contaminant
concentrations in excess of ARARs or risk-based levels.
Air Response objectives
The last objective is to prevent inhalation of air which contains
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contaminant concentrations in excess of ARARs or health based
levels of concern.. state of Ohio air emissiQn standards will be
met by the remedy.
VIII.
DESCRIPTION OF ALTERNATIVES
During the FS, U.s. EPA and OEPA identified and evaluated a
number of alternatives that could be used to address the threats
and/or potential threats identified at the site. A range of
potential technologies were examined to meet the response
objectives. For convenience, soil and'groundwater technologies
were examined separately. Although the interaction between soil
and groundwater is important when considering site-wide
alternatives, the general response actions for soil and
groundwater were established separately, leading to groups of
Remedial Technologies, and finally Specific Process Options.
After the' process options, specific technologies were assembled.
Each technology was evaluated with respect to its ability to meet
the response objectives. Based on the retained process options
applicable to the general response action, alternatives were
developed which present a reasonable range of options for each of
the environmental media considered (soil, groundwater, and air).
It is convenient to consider soil alternatives as source control
options for the chemicals of concern, while groundwater
alternatives involve plume .containment or active restoration of
the aquifer.
Institutional Controls
All of the alternatives will include institutional controls to
prevent residential exposure until the remedial action objectives
have been met. The affected area is owned by three entities
(UTA, the adjacent railroad, and the City of Zanesville). UTA
site access will be minimized by maintaining the fence around the
UTA facility. Warning signs will also be posted. Access will be
restricted at the city well field for specific areas
encompassing the interceptor well system. A fence or similar
device with warning signs will be used to minimize access to the
interceptor wells, the discharge pipes, and any treatment system.
Restrictions will be sought on the UTA property deed to control
future use of the site until soil clean up levels have been met
and to control the use and placement of wells in the affected
area until groundwater cleanup levels have been met. The local
permit process may also be used to limit future installation of
groundwater wells in the area of contamination.
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Groundwater containment Alternatives
A series of interceptor wells are installed' in or down gradient
of the contaminated area in typical groundwater containment
networks. They are utilized in order to pump contaminated
groundwater from the aquifer to the surface for treatment and
subsequent discharge to a surface water body or a Publicly Owned
Treatment Works (POTW).
Four different groundwater containment alternatives have been
evaluated. One alternative is the no action alternative that is
required by the NCP. The three remaining alternatives consider
various numbers of interceptor wells. A Pre-Design study will be
conducted to determine the exact number and location of
interceptor wells.
The response objectives for the three active containment
alternatives are to contain/capture the contaminated groundwater
plume utilizing interceptor wells. Continued groundwater
extraction will be utilized for aquifer remediation to achieve
clean up levels throughout the' contamination plume. Since there
are sOme data gaps, the exact number of interceptor wells and'
their location cannot be determined until the pre-design study is.
completed. For cost purposes, three different alternatives were
developed for achieving containment/capture and rapid aquifer
restoration. Alternative GWC-2 used the existing four UTA
interceptor wells, and two city wells W-6, W-12, and possibly W-7
to capture/contain the plume. Alternative GWC-3 uses all wells
described in GWC-2 plus two additional interceptor wells.
Alternative GWC-4 uses all wells described in GWC-2 plus 5
additional interceptor wells.
Pre-Design study
A computer groundwater model was developed by the Geraghty and
Miller modeling group and presented in the FS to evaluate the
existing groundwater flow conditions and to predict future TCE
and DCE concentrations in groundwater. During the comparison of
the groundwater data generated during the RI and the groundwater
data produced by modeling, several data gaps became apparent.
The model predicted the contamination may be flowing toward one
of the city wells and was not being completely contained. None
of the city wells currently show any evidence of contamination.
Several monitoring wells will be added in and between the known
area of contamination and the city drinking water wells in order
to confirm that no contamination is moving toward the city
drinking water wells. Data on the direction of groundwater flow
can also be obtained from these wells.
Another important data gap is the rate (gallon per minute) that
each city well is pumping. The model estimated the rate based on
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the overall pumping from the whole city well field. There is
also a public concern that additional contamination is entering
the city well field from an old closed landfill. Additional
monitoring wells will be installed on the east side of the well
field to confirm or deny this possibility.
This additional data will be used to determine if containment of
the plume is being achieved. If containment is not being
achieved the data will help determine the number of additional
interceptor wells and their location in order to achieve
containment of the plume. The additional data will also help
determine the number of additional interceptor wells that best
achieves the u.s. EPA goal of rapid aquifer restoration for this
site. The current groundwater model indicates a range of clean
up time from 10 years to less than 10 years. This range is based
on no additional interceptor wells affecting the sources and no
additional ISVE wells affecting the sources. The FS states that
source control, such as in-situ vapor extraction (~SVE), along
with pulse pumping and additional interceptor wells in the heart
of the plume can significantly shorten the aquifer restoration
time frame.
The field work will include additional groundwater monitoring
wells, additional sampling and analyses of the groundwater
monitoring wells and contaminated or potentially contaminated
city wells at the well head and at the final point of discharge
of W-6 and W-12, installation of flow meters on the City of
Zanesville water wells to determine the rate of flow,
the Muskingum River sediments may also be required to sampled and
analyzed, and the addition of monitoring wells east of the city
interceptor wells.
This data will be used to determine removal efficiency of the
City's present treatment process, its mass loading of VOCs to the
air, and its mass loading of VOCs to the Muskingum River to
determine if further treatment is necessary and if air emission
controls are necessary. Also this data will be used to determine
if the Muskingum River is a significant source of VOCs.
Based on the results of the additional field data and groundwater
model runs, it will be determined which groundwater containment
alternative effectively captures/contains the contaminant plume
and if system modifications are necessary to rapidly achieve
clean up levels. Modifications may include different pumping
rates or additional interceptor wells. This evaluation of the
system effectiveness will continue on a yearly basis until clean
up is achieved. After the groundwater clean up levels have been
met and the u.s. EPA allows the containment system to be shut
off, groundwater will be monitored to ensure the clean up levels
are maintained.
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In order to evaluate a pump and treat system, groundwater quality
data from monitoring wells is essential. The frequency of
sampling, the chemical parameters to be analyzed and the number
of monitoring wells to be sampled could be modified as cleanup
progresses. Initially, monitoring wells will be sampled on a
quarterly basis to establish a data base. The effectiveness of
the remedy will be evaluated on the data base and not solely on
simulated modeling results.
Alternative"GWC-1: No Action
Under this alternative, no response action would be taken and the
interceptor wells at the UTA facility and the city well field
would be turned off. The purpose of this alternative is to
examine the consequences of no action from a public health and
environmental standpoint. Groundwater beneath the UTA facility
exceeds MCLs and with no interceptor wells in operation the plume
of TCE and DCE would move northward and contaminate Zanesville
wells currently being used for drinking water. This could result
in contamination of a major portion of the aquifer currently used
by the City of Zanesville. There is no direct cost associated
with the No Action alternative.
Alternative GWC-2: utilize Existinq Interceptor Wells
operation of the four interceptor wells at the UTA facility and
Municipal wells W-6, W-12 and possibly W-7 would be continued
under this alternative. Regular operation and maintenance (O&M)
would continue in order to ensure the effectiveness of the system
until clean up levels are met. O&M activities would include well
and pump maintenance, repair, monthly sampling and flow
measurements, and quarterly inspection and evaluation of the
entire system.
As with all of the containment alternatives, the Pre Design study
discussed above will be performed.
The yearly evaluation of the system effectiveness will continue
until clean up is achieved. After the groundwater clean up
levels have been met and the U.s. EPA allows the containment
system to be shut off, groundwater would be monitored to ensure
the clean up levels are maintained.
The estimated cost of this alternative is:
capital Cost
Present Worth of Annualized O&M
Total Present Worth 10 Years @ 5%
$ 0
$487.200
$487,200
~
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Alternative GWC-3: Install Two Additional Interceptor Wells
This alternative is similar to Alternative GWC-2, but includes
two additional interceptor wells located north and south of the
existing system in order to enhance plume capture based on
groundwater modeling results. The actual locations would be
. determined in pre-design. The groundwater model predicted that
GWC-3 appears to capture/contain more of the TCE, DCE plume than
GWC-2 would, however it may not completely capture/contain the
plume. The model also predicted that it would take less than 10
years to remediate the aquifer and achieve groundwater clean up
levels, however, an accurate number of years could not be
determined due to limitations with the current model.
The pre-design study will have to be performed in order to
determine if this alternative achieves all clean up objectives.
The yearly evaluation of the system effectiveness will continue
until clean up is achieved. After the groundwater clean up
levels have been met and the u.s. EPA allows the containment
system to be shut off, groundwater would be monitored to ensure
the clean up levels are maintained. . .
The estimated capital and O&M costs for the alternative is:
capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 Years @ 5%
$ 75,000
$602.000
$677,000
Alternative GWC-4: Ins~all Five Addi~ional In~erceptor Wells
This alternative is similar to alternative GWC-2, but includes
five additional interceptor wells located around the UTA
facility. Two of the wells would be in the same location as in
alternative GWC-3 in order to enhance plume containment. The
three additional wells serve to accelerate the rate of removal of
affected groundwater. Based on groundwater modeling results,
GWC-4 appears to capture/contain more of the TCE and DCE plume
than GWC-2 or GWC-3, however, it may not completely contain the
plume. Alternative GWC-4 has the fastest rate of groundwater
remediation of the alternatives.
The pre-design study will have to be performed in order to
determine if this alternative achieves all of the clean up
objectives.
The yearly evaluation of the system effectiveness will continue
until clean up is achieved. After the groundwater clean up
levels have been met and the u.s. EPA allows the containment
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system to be shut off, groundwater would be monitored to ensure
the clean up levels. are maintained.
The estimated capital and O&M costs for the alternative is:
capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 Years @ 5%
$ 168,600
$ 950.300
$1,118,900
Groundwater Treatment Alternatives
UTA has operated an interceptor well and treatment system at its
facility since 1983. All of the containment alternatives assume
the four UTA interceptor wells and the city wells.W-6, W-12 and
possibility W-7 would continue pumping and discharging
to the Muskingum River. Discharges to the Muskingum River would
meet the state of Ohio discharge standards, which meet the
substantive requirements of an NPDES permit.
Four process options for ground-water treatment are examined in
detail: 1) air stripping (with and without air emission
controls); 2) UV/oxidation; 3) biological treatment; and 4)
liquid phase activated carbon. Each alternative assumes that the
existing air stripper would continue to operate under existing
flow and discharge conditions.
In order to adequately determine preliminary sizing for the
treatment systems that are being assessed, appropriate ground-
water treatment parameters have to be established. Since a new
treatment system would be used in combination with either ground-
water collection Alternative GWC-3 or Alternative GWC-4, th~ flow
rate into the system would be dictated by the amount of flow
produced by the respective interceptor wells. The expected flow
rates are estimated to be 400 gpm for Alternative GWC-3 and 1,000
gpm for Alternative GWC-4. Thus, for each new treatment system
being assessed these two design cases need to be considered.
A contingent alternative was developed to. treat excess flow from
the existing interceptor well I-1. In the event that VOCs in
the direct discharge of groundwater from I-1 to the Muskingum
River exceed State of Ohio discharge standards, then available
capacity of the existing air stripper system will be exceeded and
an additional treatment system will be required. The direct
discharge of well I-1 would not be allowed if it failed to meet
the state of Ohio discharge standards, which meet the substantive
requirements of an NPDES permit. The preliminary hydraulic
capacity.of the new system will need to be about 270 gpm.
Therefore, the contingent treatment system has been preliminarily
sized to treat a flow rate of 300 gpm.
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A second contingent alternative was developed in the event that
the direct discharge from the city interceptor wells requires
treatment because it exceeds the state of ohio discharge
standards, which meet the substantive requirements of an NPDES
permit. An air stripper was considered for this treatment.
Alternative GWT-1A: Air stripper Without Emission Controls
Under this alternative, an additional air stripper would be
constructed to treat additional flow as a result of the
implementation of Alternative GWC-3 or GWC-4, at the design flow
rates of 400 gpm and 1000 gpm respectively. The air stripper
would be a counter-current type, and constructed of fiberglass
reinforced plastic or epoxy coated steel. Randomly dumped
packing material (plastic or ceramic) wo~ld be used as the
stripping media inside of the tower. Groundwater from the
interceptor wells would be pumped to the top of the tower and
allowed "to flow by gravity against an air stream supplied by a
blower mounted near the bottom of the air stripper. The air
stripper would be designed to "remove TCE and DCE so that its
discharge will meet state of Ohio discharge standards, which meet
the substantive requirements of an NPDES permit. The air
stripper would be built on a concrete slab, but no building would
be constructed for weatherization. Galvanized discharge piping
would be used, and piping would be insulated or heat traced as
required to prevent freezing. Iron fouling of the packing media
in the existing air stripper is a known problem, because ferrous
iron (Fe+2) is present in extracted groundwater. Fouling
problems lead to increased operating costs due to an excessive
pressure drop in the tower, and reduced removal efficiency due to
reduced air water contact area, and channeling effect.
Therefore, an integrated acid wash/chlorination system would be .
designed into the tower in order to clean the packing material'
without the need for disassembly.
No treatment of the discharge air stream would occur under this
alternative. Assuming a 99% removal efficiency and the average
concentrations to the air stripper over the past year, the
estimated VOC mass emission rate is 2.7 lb/day to 6.6 lb/day, for
a groundwater flow rate of 400 gpm to 1000 gpm respectively. In
order to ensure that the air stripper efficiency is optimized,
regular operation 'and maintenance activities would be required.
These activities include continued sampling of influent, and
effluent, maintenance of pumps, blowers, and other mechanical
equipment, and a regular schedule of air stripper packing
cleaning and replacement, as necessary.
The estimated capital and O&M cost for Alternative GWT-1A are
shown below:
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,Design Case 1: In combination with Alternative GWC-3 (400 gpm)
capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 88,900
$256.600
$345,500
Design Case 2: In combination with Alternative GWC-4 (1000 gpm)
capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$149,700
$302.800
$452,500
Alternative GWT-l B: Air stripper with Emission Controls
Alternative GWT-1B is identical to Alternative GWT-1A except that
the air stripper vapor emissions would be treated with granular
activated carbon (GAC) prior to discharge to the atmosphere. One
GAC absorber with an 8000 lb carbon capacity would be used for
the,400 gpm design case, and two absorbers in parallel would be
used for the 1000 gpm design case. A preheater would be used to
raise the temperature and lower the relative humidity of the air
stream prior to vapor phase treatment. The heater would increase
the efficiency of the activated carbon. The estimated capital
and O&M costs for Alternative GWT-1 B are shown below:
Design Case 1: In combination with Alternative GWC-3 (400 gpm)
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$126,400
$764.800
$891,200
Design Case 2: In combination with Alternative GWC-4 (1000 gpm)
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 225,900
$1.239.600
$1,465,500
Alternative GWT-l Bl
Groundwater extracted from interceptor well 1-1 may need to be
treated, instead of ,the current practice of being directly
discharged to the river, in order to meet the state of Ohio
discharge standards, which meet the substantive requirements of
an NPDES permit. If treatment is required an air stripper or an
equal or superior technology would be implemented. Therefore a
contingent air stripper alternative has been developed to handle
excess flow from the existing interceptor well. If additional
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interceptor wells are added, this contingent alternative would
not be implemented since the treatment for the new wells would be
designed to accommodate any excess flow from the existing system.
For cost estimating purposes, the assumed design flow rate of
this system is 300 gpm, which is approximately the flow rate.
currently being bypassed to the river. The estimated capital and
O&M cost for Alternative GWT-1 B1 is:
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$108,300
$751.300
$859,600
Alternative GWT-1 c: Utilize Existing Air stripper
Under this alternative, the existing air stripper system would
continue to operate without increased or decreased flow. It .
would be implemented with the existing containment Alternative
GWC-2. No additional equipment would be installed, although
operation and maintenance activities would continue in order to
maintain the system effectiveness. Alternative GWT-lB1 may also
be required to be implemented to treat interceptor well 1. There
are no capital Costs associated with Alternative GWT-1 C. The
estimated O&M costs are shown below:
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 0
$256.600
$256,600
Alternative GWT-2: UV/oxidatioD
Alternative GWT-2 would utilize ultraviolet light in combination
with chemical oxidation (UV/oxidation) for groundwater treatment.
The particular process equipment evaluated is manufactured by
Ultrox International, Santa Ana, California. A typical UltroxR
system consists of an oxygen or air source, an Ozone (03)
generator, a hydrogen peroxide (H202) feed system, a UV/oxidation
reactor, an Ozone (03) decomposition unit. Influent from the
interceptor wells would first enter a tank and be mixed with H202
then pumped into the reactor, sparged with 03 gas, and
simultaneously exposed to UV light. Unreacted 03 would be
decomposed by a catalytic unit downstream of the UV/oxidation
reactor. Treated water would be discharged to the Muskingum
River via the North Catch Basin.
Groundwater at the UTA site is classified as very hard because of
the high concentrations of divalent cations. H202 and 03 are
strong oxidants which can oxidize the dissolved iron in the
groundwater to a relatively insoluble precipitate. This
precipitate can coat the UV lamps, decreasing their intensity,
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and thus decreasing the overall treatment system efficiency.
Pretreatment of the extracted groundwater (such as lime
softening) would be necessary in order to prevent excessive
maintenance shut downs due to poor treatment efficiency from
scaling and oxidation of iron and manganese in the extracted
ground-water.
Another approach to prevent iron fouling involves the addition of
a sequestering agent in order to keep the iron in solution as the
groundwater undergoes treatment.
UV/oxidation is an attractive technology because it destroys
oxidizable chemicals. Therefore, the risk of exposure to these
chemicals would be permanently eliminated. During operation
there would be no treatment residuals or atmospheric discharges
of chemicals of concern from the reactor. However a pretreatment
system for hardness would be re~uired. This may generate an
estimated 1000 yd3/yr to 2500 yd/yr of non hazardous waste that
would have to be disposed. The estimated capital and O&M cQsts
for Alternative GWT-2 are:
Design Case 1: In combination with Alternative GWT-2 (400gpm)
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$1,017,500
$ 957.400
$1,974,400
Design Case 2: In combination with Alternative GWC-4 (1,000 gpm
for 9 years)
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$2,033,900
$1. 417 . 300
$3,451,200
Alternative GWT-3: Biological Treatment
Biological treatment of groundwater at the UTA site can
potentially be accomplished through treatment in an above ground
biological reactor containing bacteria and nutrients. The
bioreactor evaluated for this application is a fixed-film
reactor. This technology utilizes the growth of organisms on a
biofilm. A healthy biofilm is grown within the bioreactor using
a supplemental feed of organic carbon. When the biofilm has
sufficiently matured, the waste stream to be treated is fed" into
the reactor. with typical total organic chemical concentrations
in the groundwater at around 600 ug/L, the bioreactor's effluent
can potentially achieve the state of Ohio substantive
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requirements of an NPDES permit. A pilot test will be required
to confirm the effluent concentrations. The estimated capital
and O&M costs for Alternative GWT-3 are:
Design Case 1: In combination with Alternative GWC-3 400 gpm
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 930,000
$1.254.500
$2,184,500
Design Case 2: In combination with Alternative GWC-4 1000 gpm.
Capital Cost
Present Worth of Annualized O&M
Total Present Worth (9 years, 5%)
$1,802,500
$2.836.000
$4,638,500
Alternative GWT-4: Activated Carbon
Alternative GWT-4 would use granular activated carbon for the
removal of TCE and DCE from the recovered groundwater. Activated
carbon functions to remove organic compounds from solution
through an adsorption process in which compounds enter molecular
size pores in the carbon and remain there due to molecular
attraction. Activated carbon is a proven treatment technology
that is used extensively for removing soluble organic compounds,
as well as some inorganic compounds, from solution. The carbon
in the system would need to be replaced approximately three to
four times per year. Once the adsorption capacity of the
activated carbon is exhausted, the spent carbon would be
reactivated, and the TCE and DCE would undergo complete thermal
destruction. The carbon can then be reused. Treated groundwater
would be discharged to the Muskingum River in compliance with the
state of Ohio discharge standards, which meet the substantive
requirements of an NPDES permit. The estimated capital cost and
O&M costs for Alterative GWT-4 are:
Design Case 1: In combination with Alternative GWC-3 (400gpm)
capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 284,000
$1.066.900
$1,350,900
Design Case 2: In combination with Alterative GWC-4 (1000gpm)
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 9 years @ 5%
$ 511,000
$2.339.200
$2,850,200
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Alternative GWT-S: Air stripper Treatment in the Zanesville Well
Field
Under this alternative, an air stripping system would be
constructed at the Zanesville Well Field, if the extracted
groundwater from the existing well system (W-6 and W-12 or
possibly W-7) exceed the state of Ohio discharge standards, which
meet the substantive requirements of an NPDES discharge permit.
These wells currently discharge using a simple aeration device
directly to the Muskingum River. Prior to implementing this
remedy, a sampling effort would be undertaken in order to
determine contaminant concentration in the groundwater being
discharged to the Muskingum River using the existing system. If
the discharge is below the state of Ohio discharge standards',
which meet the substantive requirements of an NPDES discharge
permit, no treatment would be required. ~f a new treatment
system is necessary, each extraction well would be piped to a
central location, and groundwater would be pumped to the top of
an air stripping tower. The air stripper must be evaluated
pursuant to the BAT requirements outlined in OAC 3745-31-05 prior
to the determination that air emission controls are required.
Air emissions from the air stripper would be treated using
activated carbon vessels. Treated groundwater would be
discharged to the Muskingum River below the state of Ohio
discharge standards, which meet the substantive requirements of
an NPDES permit.
The estimated capital cost and O&M cost for Alterative GWT-5 are:
capital Cost $265,700
Present Worth of Annualized O&M $282.600
Total Present Worth 4 years @ 5% $548,300
SOIL REMEDIATION ALTERNATIVES
There are a limited number of areas which currently exceed soil
clean up levels. All of the areas requiring soil remediation are
on the UTA facility. Isolated "Hot spots" of soil affected by
inorganic constituents were identified during the Phase II RI.
TCE was detected above the clean up level in several soil borings
and one soil sample contained DCE above the clean up level. The
areas where contaminants above cleanup levels were detected are
around the former drum storage area, the north catch basin area
(including the northeast corner of the building), and the former
above ground bulk storage tank. However, additional. remediation
may be required around the areas associated with the clay tile
system. .
The groundwater being pumped by the four UTA interceptor wells
has shown a general declining trend in the concentrations of
VOCs. Concentrations of VOCs in interceptor well I-4 have not
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2S
decreased as readily as in interceptor wells I-1, I-2 and I-3.
Interceptor well I-4 was installed three years after the other
three interceptor wells. Interceptor well I~4, which is' located
between the plant and the other three interceptor wells and
furthest from the river, removes on the average 1.7 pounds per
day of VOCs from groundwater. Also the soil vapor extraction
system located at I-4 has consistently removed between 0.3 to 1
pound per day of VOC vapors. The Feasibility Study concluded
that a currently undetermined source of VOCs may be contributing
to the concentrations observed in interceptor well I-4. It is
suspected that the aquifer, or the saturated zone, and the
unsaturated zone above the water table may be acting as a source
for VOCs. During Remedial Design, additional studies will be
performed to determine the location and extent of the source.
The soil cleanup alternative will be adjusted as necessary to
include this possible source.
It is believed that remediation of this possible source area
would significantly decrease the time frame to achieve the
remediation of the groundwater.
Alternative 8-1: No Action
Under Alternative S-l, no further action would be undertaken to
remediate soils at the site and minimal actions such as
additional monitoring may be undertaken. Only natural
attenuation mechanisms would be responsible for changes in
concentrations of VOCs. There are no direct costs associated
with the No Action alternative.
Alternative 8-2: Multi-Media Cap
Under Alternative S-2, a multi-media cap will be placed over the
area affected by both inorganic and organic constituents. The
purpose of such a cap is to eliminate the potential for direct
contact with affected soils and minimize surface water
infiltration which may leach constituents into groundwater. The
multi-media cap would be designed and constructed to meet the
technical requirements described in 40 CFR Part 264. These
requirements include a minimum 2-foot thick vegetative layer, a
minimum 12-inch thick drainage layer, and a low permeability
layer of compacted clay with a synthetic liner. The estimated
capital and O&M costs for Alternative S-2 are:
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 30 years @ 5%
$133,300
S 76.900
$210,200
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26
Alternative S-3: Excavation and Off-site Landfill Disposal
Alternative S-3 is directed at eliminating potential sources
which may affect groundwater quality. Soil exceeding the clean
up levels will be excavated and transported off-site, to an off-
site RCRA/CERCLA compliant Subtitle C (hazardous waste) landfill.
Clean soil would be brought from outside sources and used as
backfill to restore the excavated area to original grade. The
estimated capital and O&M costs of Alternative S-3 are shown:
Capital Cost
Present Worth of Annualized O&M
Total Present Worth
$8,325,000
$ °
$8,325,000
Alternative S-4(A): Vapor Extraction
organic contaminant Treatment
Alternative S-4(A) is a source control alternative consisting of
active remediation of VOCs in the unsaturated soils using in-situ
vapor extraction (ISVE). Inorganic constituents of concern will
have to be treated by another soil Alternative such as S-4(B)
limited excavation and disposal, or S-6 soil washing. Several
areas were identified for vapor extraction: south of the former
drum storage area (near the north east corner of the main
facility building); North Catch Basin area; and portions of the
clay tile system. These areas were selected by comparing
analytical results from soil and soil gas samples with calculated
clean up levels. Based on this comparison, the constituents of
concern are TCE and DCE. Although the exact depth limit of soil
contamination is not known it is believed to be within the upper
half of the 40 foot unsaturated zone. The extracted VOCs will be
adsorbed onto activated carbon. The activated carbon will be
reactivated and reused by thermally destroying the VOCs.
A major area also requiring ISVE is believed to be the source
area. The source area will be further defined and located
through the pre-design studies. It is believed that rapid
remediation of this source area would significantly reduce the
time frame to reach the groundwater clean up levels. Rapid
source area remediation will be an ISVE design requirement.
The application of ISVE is appropriate for these areas based on
the following considerations: 1) TCE has a Henry's Law constant
that favors partitioning into air-filled soil pore spaces; 2) The
sand-silt soils are anticipated to be permeable enough to .
accommodate typical air flow rates and applied vacuum conditions;
and 3) ISVE influences a broad area, and its effectiveness is not
affected by local concentration variations within the area.
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Prior to design and construction of a ISVE system, a pilot study
will be conducted to develop site specific information as a basis
for the establishment of system design criteria. The pilot study
will develop information based on specific site variables, such
as depth to ground-water, soil permeability, moisture content,
stratigraphy, porosity, and the vertical and horizontal
concentration of VOC vapors in the soils. This information will
. be used to design the system and specify the number of wells,
their locations, depths, zone of influence, and rate of vapor
extraction. During the pilot study, the need for a temporary cap
to enhance the rate of VOC extraction would be evaluated. The
length of time to achieve clean up levels would be from 7 to 29
years. For cost estimating purposes, an estimate of 10 years was
used.
The estimated capital and O&M costs of Alternative S-4(A) is
Total Capital Cost
Present Worth of Annualized O&M
Total Present Worth 10 Years @ 5%
$193,750
$286.500
$480,250
Alternative S-4(B): Limited Excavation and Disposal
Inorganic Treatment
There are several areas preliminarily identified as potentially
requiring excavation and disposal due to inorganic constituents
of concern above the calculated clean up levels. These areas are
north and south of the former drum storage area, around the
former bulk storage tank, and around the former dug well. This
would be implemented after ISVE has been completed. For cost
estimating purposes, the total volume of soil to be excavated was
estimated based on an assumed 15 foot radius of excavation and
the maximum depth at which constituents of concern greater than
the clean up levels were detected. Based on these calculations,
the estimated volume of soil for excavation and disposal is 1800
cubic yards. Additional soil .borings will be completed in these
areas in order to better define the horizontal and vertical
extent of affected soil. All soil taken off site will meet the
state of Ohio requirements for solid or hazardous waste.
The estimated capital and O&M costs for Alternative S-4-B are:
Capital Cost
Present Worth of Annualized O&M
Total Present Worth
$416,250
$ 0
$416,250
Alternative 8-5: Excavation and Off-site Incineration
Alternative 5-5 is similar to Alternative 5-3 (excavation and
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28
landfilling) with substitution of incineration for landfilling.
Affected soils will. be excavated and transported to a RCRA/CERCLA
compliant off site commercial incinerator. .Clean soil would be
utilized for backfill to restore the excavated area. The volume
of soil to be excavated and incinerated is 36,000 cubic yards.
The estimated capital and O&M costs of Alternative S-5 are:
capital Cost
Present Worth of Annualized O&M
Total Present Worth
$10,575,000
S 0
$10,575,000
Alternative S-6: soil Washinq
Inorqanic Treatment
Under this alternative, soils which exceed the inorganic
constituent soil clean up levels, (the same areas as Alternative
S-4(B) Limited Excavation and Landfilling) will be excavated and
. treated in an above ground washing system. The areas to be
treated are north and south of the former drum storage area, the
former bulk storage area, and the abandoned dug well. Please.
refer to section VII, REMEDIAL ACTION OBJECTIVES of this ROD, for
more information on the cleanup levels. Soils contaminated with
VOCs would be treated using the Organic Tr~atment Alternative s-
4(A) ISVE. Soil washing of soils containing inorganics (e.g.
lead & mercury, etc.) would occur after completion of the ISVE
portion of the remedy in order to limit VOC emissions during the
required excavation activities.
Typical soil washing techniques operate by excavating all soils
exceeding the clean up levels and staging the soils in working
piles for processing. Each pile may be placed on mechanical
vibrating screens in order to remove any oversized materials.
Hydraulic separation may then be performed in hydrocyclones,
followed by gravity separation in order to produce coarse and
fine grained materials. Actual soil washing may be accomplished
in floatation cells, the end products of which are concentrated
waste and filter cake from generated sludge which requires
further processing (i.e. off-site disposal or further off-site
treatment).
Soil testing will be performed prior to excavation to determine
if site soils are a RCRA characteristic hazardous waste. If the
soils are a characteristic hazardous waste, they will be treated
to meet land disposal restriction standards, as well as the
hazardous waste requirements listed below prior to replacement.
If the soils are a hazardous waste, any interim waste pile will
comply with Ohio Administrative Code (OAC) section 3745-56-50
through 3745-56-60. If the soils are not a hazardous waste, the
working piles will be made to minimize wind dispersal and run-on
/run-off of liquids. The concentrated waste and filter cake will
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be tested per 40 CFR 261.20 to determine if it is hazardous
waste. If it is a hazardous waste or a solid waste, it will be
handled according to all applicable OAC and CFR requirements.
All waste water will be managed in compliance with all applicable
state and Federal requirements.
Clean soil material may be replaced in the ground if it is not
considered a solid waste pursuant to ORC 3734.01(E) or if it
qualifies for an exemption pursuant to ORC 3734.02(G). Process
water would be recycled through the soil washing system. A pilot
test will be necessary to ensure that soil washing would be
effective for the soil and chemical constituents found at the
site. If during pilot studies, it is determined that the soils
are considered a solid waste and do not qualify for a solid waste
exemption, other treatment and disposal options will be
evaluated.
The estimated capital and O&M costs of Alternative S-6 are:
capital Cost
Present Worth of Annualized O&M
Total" Present Worth 5 years @ 5%
$625,000
S 42.000
$667,400
Alternative 8-7: Zn-8itu vitrification
Alternative S-7 would eliminate potential source areas by
utilizing In-Situ Vitrification technology (ISV). The ISV
process uses high temperature electric melting to treat the soil
matrix. Organic constituents are destroyed and inorganics, with
the exception of mercury, are immobilized into a glassified
residual product. Mercury vapor and other off gasses would be
treated by a surface system. An array of electrodes would be
placed around the area to be treated, and driven to the target
~epth. An electric pot7ntial would be af,plied to the electrodes
~n order to heat the so~l to about 2,000C. At these
temperatures organic constituents would be pyrolyzed and rise to
the surface of the vitrified zone where they would combust at the
surface in the presence of oxygen. An off-gas hood would be
placed over the vitrified zone during operation. "
The same location considered for treatment in Alternative S-3 is
included in this alternative using the same assumptions. The
volume of soil to be treated is 36,000 cubic yards. In addition,
the cost of treating only the inorganic constituents of concern
such as alternative S-4-B and S-6 (approximately 1800 cubic
yards) was evaluated in the event that ISV is combined with
alternative S-4(A) ISVE. "
The estimated capital and O&M costs for Alternative S-7 are:
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Case 1: 36,000 cubic yards of soil
Capital Cost
Present Worth of Annualized O&M
Total Present Worth 5 years @ 5%
"$29,243,800
$ 42.400
$29,286,200
C~se 2: 1,800 cubic yards of soil
capital Cost
Present Worth of Annualized O&M
Total Present Worth 5 years @ 5%
$1,670,000
$ 42.400
$1,712,400
IX.
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The alternatives were evaluated according to the following nine
criteria which are used by the U.S. EPA to provide the rational
for the selection of the final remedial action at a site.
A.
The Nine Evaluation Criteria
THRESHOLD CRITERIA
* Overall Protection of Human Health and the Environment
addresses whether or not the remedy provides adequate protection
and describes how risks are eliminated, reduced or controlled
through treatment, engineering controls, or institutional
controls.
* Compliance with ARARs address whether or not the remedy will
meet all of the applicable or relevant and appropriate
requirements of other environmental statutes and/or provide
grounds for invoking a waiver.
PRIMARY BALANCING CRITERIA
* Long-Term Effectiveness and Permanence refers to the ability
of a remedy to maintain reliable protection of human health and
the environment over time once clean up goals have been met.
* Reduction of Toxicity, MObility, or Volume through treatment
assesses to what degree the remedial alternatives, by utilizing
treatment technologies, will permanently and significantly reduce
the toxicity, mobility or volume of the hazardous substances at
the site. .
* Short-Term Effectiveness involves the period of time needed to
achieve protection and any adverse impact on human health and the
environment that may be posed during the construction and
implementation period until clean up goals are achieved.
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* Implementability is the technical and administrative
feasibility of a remedy including the availability of goods and
services needed to implement the chosen solution.
*
Cost includes capital and operation and maintenance costs.
MODIFYING CRITERIA
* Support Aqency Acceptance indicates whether, based on its
review of the RI/FS and Proposed Plan, the .support agency
concurs, opposes, or has no comment on the preferred alternative.
* community Acceptance will be assessed in the Record of
Decision following a review of the public comment received on the
RI/FS Report and the Proposed Plan.
B.
ComDarative Analvses of Alternatives
Threshold criteria must be met in order for an alternative to be
eligible for selection. Primary balancing criteria are used to
assess the technical and administrative trade-offs between
alternatives. As a result of the assessment of primary balancing
criteria, u.s. EPA determines which alternatives satisfy the
statutory requirement for cost-effective and permanent solutions
which utilize treatment to the maximum extent practicable.
Comments received during the public comment period will form the
basis for evaluating the alternatives relative to the modifying
criteria described above.
Overall Protection of Human Health and the Environment:
Groundwater Containment Alternatives
All of the groundwater containment alternatives, except for the
no action alternative, will provide some degree of protection of
human health and the environment because the contaminated
groundwater plume will be captured/contained and will not impact
the city drinking water wells. GWC-4 and GWC-3 provide slightly
more containment than GWC-2. The pre-design will determine the
exact number and location of wells needed to capture/contain the
plume of TCE and DCE.
Groundwater Treatment Alternatives
All of the groundwater treatment alternatives provide some degree
of protection of pUblic health and the environment. The primary
site risk of ingestion of groundwater is eliminated by .
implementing the groundwater containment alternative. Each
treatment alternative will discharge to the Muskingum River and
will be able to reduce the constituents of concern to
concentrations at or below state of Ohio discharge standards,
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which meet the substantive requirements of an NPDE5 water
discharge permit.
soil Treatment Alternatives
Alternative 5-6, remediation of inorganic constituents, provides
a high degree of protection by removing the inorganic
constituents from the soils and further treating or disposing the
treatment sludge. Alternative 5-3 and 5-4(B) will eliminate the
potential for exposure at the site but will transfer the
excavated material to a land disposal facility, where cross-media
impacts may occur.
Alternatives 5-3 and 5-5 will increase worker and residential
exposure due to the generation of dust and volatile emissions"
during excavation. Alternative S-4(B) and Alternative S-6 may
also increase worker and residential exposure due to the
generation of dust, but to a lesser degree since the volume of
soil removed is considerably less. No volatile emissions will
occur because Alternative S-4(A) will first remove the VOCs
before 5-4(B) or 5-6 is implemented. "
compliance with ARARs: SARA requires that all remedial "actions
meet legally applicable or relevant and appropriate requirements
of other environmental laws.
Groundwater containment Alternatives
Maximum Contaminant Levels (MCLs), and to a certain extent,
Maximum contaminant Level Goals (MCLGs), drinking water standards
promulgated under the Safe Drinking Water Act (5DWA), apply at
the tap to public water supplies servicing 25 or more people. At
the Zanesville Site, MCLs and MCLGs are not applicable, but are
relevant and appropriate, since the aquifer is used as a drinking
water supply by the City of Zanesville. MCLGs are relevant and
appropriate when the standard is set at a level greater than zero
(for non-carcinogens), otherwise, MCLs are relevant and
appropriate. The Groundwater containment Alternatives will
achieve these ARARs by pumping and subsequently treating the
affected groundwater until the ARARs are achieved.
The NCP, 55 Federal Register 8753, provides that groundwater
cleanup standards should generally be attained throughout the
contaminant plume or at and beyond the edge of the waste
management area when waste is left in place. The pre-design will
determine the exact number and location of wells needed to
capture/contain the plume of TCE and cis- and trans- DCE such
that MCLs (and MCLGs) are met throughout the plume. "
Groundwater Treatment Alternatives
The Clean Water Act requires the State to promulgate state water
quality standards for surface water bodies, based on the
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designated uses of the surface water bodies. CERCLA remedial
actions involving surface water bodies must ensure that
applicable or relevant and appropriate state water quality
standards are met. ORC Chapter 6111 establishes Ohio EPA's
authority to set water quality standards (Section 6111.041) and
to regulate water pollution sources. Regulations developed and
implemented by Ohio EPA under the authority contained in ORC
Chapter 6111 are in part, found at OAC Sections 3745-1-03 through
3745-1-07, inclusive, 3745-1-24, 3745-31-05, 3745-32-05 and 3745-
33-05.
At the Zanesville Site, the Groundwater Treatment Alternatives
involve treatment and discharge of groundwater to the Muskingum
River. The alternatives will meet the substantive requirements
of ORC Chapter 6111 and OAC Sections 3745-1-03 through 3745-1-07,
inclusive, 3745-1-24, 3745-31-05, 3745-32-05 and 3745-33-05.
Attachment 1 contains the State of Ohio effluent limitations for
the Zanesville Well Field Site. Additional effluent monitoring
requirements will be developed to meet the substantive
requirements of these Ohio regulations.
GWT-1B will comply with OAC 3745-31-05 because any
stripper constructed at the site will be evaluated
the BAT requirements outlined in OAC 3745-31-05 to
whether air emission controls are required.
new air
pursuant to
determine
Soil Treatment Alternatives
RCRA requirements are not applicable unless RCRA-listed or
characteristic hazardous wastes are excavated and managed
(treated, disposed or stored).
Alternative S-6 (soil washing) involves excavation, treatment and
replacement of the soils at the Site. The contaminated soils
will be tested prior to excavation to determine if the soils are
a characteristic hazardous waste. If the soils are determined to
be a characteristic hazardous waste, certain RCRA requirements,
including RCRA Land Disposal Restrictions, would be applicable.
If the soils are determined to be a characteristic hazardous
waste, Alternative S-6 would meet OAC 3745-56-50 through 3745-56-
59 for any waste piles created during interim handling
procedures. In addition, treated soils would meet LDR treatment
requirements prior to replacement and any concentrated waste and
filter cake generated by this alternative would be tested by the
TCLP test to determine if they are hazardous and treated or
disposed of off-site in compliance with RCRA.
Alternative 5-6 may also invoke State of Ohio Solid Waste
regulations. Under alternative S-6, treated soil will be
replaced in the ground only if it is not considered a solid waste
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pursuant to ORC 3734.01(E) or if it qualifies for an exemption
pursuant to ORC 3734.02(G).
The Alternative S-4(A) air emission control device would meet
applicable state of Ohio regulation OAC 3745-15-07 and OAC 3745-
16-02. The carbon adsorption filters will be re-cycled according
to the applicable federal regulations of 40 CFR 264.600 sub part
x. The Alternative S-7 air emission control off-gas hood device
will meet applicable state of Ohio regulation OAC 3745-15-07, OAC
3745-16-02. Any carbon adsorption filters will be re-cycled
according to the applicable federal regulations of 40 CFR 264.600
sub part X.
Lonq-Term Effectiveness and Permanence:
Groundwater containment Alternatives
All of the alternatives, except for no action, achieves a high
degree of long-term effectiveness and permanence by extracting
groundwater affected by chemicals of concern to a treatment
system (Alternative GWT 1 through GWT-4).
Groundwater Treatment Alternatives
Alternative GWT-l-B, GWT-2, GWT-3, GWT-4 and GWT-5 achieve the
highest level of long term effectiveness because the groundwater
constituents of concern are ultimately destroyed. Alternatives
GWT-1-A and GWT-1-C will transfer the bulk of volatile
groundwater constituents into the atmosphere. It is anticipated
that none of the alternatives will require long term operation or
monitoring after ARARs are achieved in order to maintain their
effectiveness.
soil Treatment Alternatives
Each alternative, with the exception of Alternative S-l (No
Action), provides some degree of long-term effectiveness and
permanence. Alternative S-l will allow continued leaching of
constituents to groundwater and potential exposure of residents
to contaminated soils.
The effectiveness and permanence of Alternative S-2 assumes the
multi-media cap is not disturbed in the long-term. Alternative
S-3, S-4(B), S-5 and Alternative S-6 provide the greatest degree
of long-term effectiveness and permanence because the affected
soils are removed from the site or treated. Alternative S-4(A)
provides a moderate to high degree of permanence through the in-
situ removal of VOCs in the soil. Alternative S-4(A) also
provides the most effective treatment of the source areas.
Alternative S-7 also provides a high degree of long-term
effectiveness and permanence by destroying organic constituents
and transforming the metals and soils into a vitrified mass.
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Reduction of Toxicity, MObility, or Volume:
Groundwater containment Alternatives
This criterion relates to treatment aspects of an alternative and
is therefore not applicable to the containment alternatives.
Groundwater Treatment Alternatives
Alternative GWT-1B, GWT-2, GWT-3, GWT-4, and GWT-5 will provide
the highest degree of reduction of chemical toxicity, mobility,
or volume by destroying extracted organic chemicals in the
identified groundwater plume. Alternatives GWT-1-A and GWT-1-C
do not provide any reduction of the mObility, toxicity, or volume
of the contaminants because it transfers volatile constituents
into the atmosphere. However GWT-l-A and GWT-l-C will provide
significant reduction of contaminant loading to groundwater and
subsequently the groundwater toxicity, mobility, and volume.
Soil Treatment Alternatives
Alternative S-5 and S-7 provide the greatest degree of reduction
in toxicity, mobility, or volume through treatment, followed
closely by Alternative S-6. Alternative S-5 will thermally
destroy volatile constituents and slightly reduce the vol~me, but
inorganic constituents (metals) will concentrate in an ash.
Alternative S-7 will also thermally destroy organic constituents
(in-situ) and will immobilize inorganic chemicals in the soil by
creating a vitrified mass. Alternative S-4(A) will contain VOC
vapors on carbon, then thermally destroy the organic constituents
achieving a major reduction of toxicity, mobility or volume
through treatment.
Alternative S-l, S-2, S-3, and S-4(B) do not provide any
treatment of the affected soil, nor do they provide any reduction
in toxicity, mobility, or volume.
Short-Term Effectiveness:
Groundwater Containment Alternatives
Construction related adverse impacts will be minor for all of the
containment alternatives since a relatively small amount of
subsurface material containing chemicals of concern require
handling.
The U.S. EPA groundwater policy as described in the NCP states
that the EPA's preference is for rapid restoration, when
practicable, of contaminated groundwater that is currently a
drinking water source. It also states that reasonable
restoration time periods may range from very rapid, 1 to 5 years,
to relatively extended, perhaps several decades. The U.S. EPA
proposes aggressive source control through ISVE in combination
with aggressive containment and achievement of clean up levels.
This will, therefore satisfy both the NCP preference for rapid
restoration and overall site objectives.
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Alternative GWC-4 offers the greatest degree of short-term
effectiveness with the addition of five interceptor wells.
Alternatives GWC-3 and GWC-2 offer short-term effectiveness in
descending order, respectively. GWC-3 provides for two
additional interceptor wells and GWC-2 provides continued
operation of the existing interceptor system.
The exact number of years to achieve ARARs could not be
determined at this time based on limitations within the
groundwater model. Also, the model did not adjust the source for
additional interceptor wells or aggressive source control using
ISVE. .
Groundwater Treatment Alternatives
All of the treatment alternatives have approximately the same
degree of short-term effectiveness since this factor is
controlled by the groundwater containment alternative.
Construction related adverse impacts will be minor for each
alternative. .
soil Treatment Alternatives .
Alternatives S-3, S-4(B), S-5, and S-6 will cause slight to
moderate adverse impacts to on site personnel and the surrounding
residents due to air emissions during excavation. Alternative 5-
4(A) will present only a slight adverse impact during
construction and implementation. Alternative S-6 and S-7 will
cause slight adverse impacts during construction and may
inconvenience employees at the UTA facility because of space
requirements during construction implementation. Estimated time
for construction, and time to reach clean up levels and ARARs for
each alternative are shown below:
Alternative
Time to Construct
Time to Meet ARARS/Clean UD
5-1
5-2
S-2
S-3
5-4a
S-4b
S-5
S-6
S-7
NA
1 week
1 week
1 week
4 weeks
1 week
1 week
4 weeks
4 weeks
NA
NA
1 week
10 years
NA
1 week
4 weeks
4 weeks
Implementability:
Groundwater containment Alternatives
All of the containment alternatives are readily implementable
because they use standard construction techniques and commonly
available material and labor.
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Groundwater Treatment Alternatives
All of the alternatives are implementable, although GWT-1-A, GWT-
1-B, GWT-1-C, GWT-4, and GWT-5 are most readily constructed and
operated because they utilize conventional, proven methods. The
implementability of GWT-2 and GWT-3 is fair because of the
requirement for trained operators and significant maintenance
,activity in order to maintain their effectiveness.
Soil Treatment Alternatives
The technical feasibility of each soil alternative is very good,
with the possible exception of Alternative S-6 and Alternative
S-7. Soil washing and vitrification are relatively new
innovative technologies for waste treatment. Although these
alternatives will require pilot testing to assess their
effectiveness, theNCP states a preference to consider innovative
technologies when they offer comparable or superior treatment
performance. Any delays due to pilot testing of the Inorganic
Alternative will have little effect since the alternative will
not be implemented until Alternative S-4(A) nears completion.
Alternatives S-2, S-6 and S-4(A) can be easily modified in the
event of remedy failure. If Alternative S-7 were to fail,
implementation of additional remedial actions may be difficult
due to the nature of the vitrified mass. If it is determined
after the ISVE pilot study and the pre-design study that S-6 will
not be effective or able to meet ARARs, other treatment
alternatives will be evaluated.
Cost:
Groundwater containment Alternatives
The present worth cost of each alternative is shown below:
Alternative CaDital Cost O&M (PW) Present Worth
GWC-1 $ 0 $ 0 $ 0
GWC-2 $ 0 $ 487,200 $ 487,200
GWC-3 $ 75,000 ~ 602,000 $ 677,000
GWC-4 $ 168,600 $ 950,300 $1,118,900
The no action alternative will have the lowest cost, however, the
remedial action objectives will not be met. The existing
interceptor wells system has a cost of $487,200 however, it is
uncertain based on the model if the remedial action objectives,
and goal of rapid restoration will be met. The addition of two
interceptor wells have a cost of $ 677,000 and the addition of
five interceptor wells have a cost $1,118,900. These two'
alternatives have a higher degree of certainty of achieving the
remedial action objectives and rapid restoration.
Groundwater Treatment Alternatives
The Present Worth' Cost of each alternative is presented below:
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38
Alternative Capital O&M (PW) Present Worth
GWT-1A(400 gpm) $ 88,900 $ 256,600 $ 345,500
GWT-1A(1,000 gpm) $ 149,700 $ 302,800 $ 452,500
GWT-1B(400 gpm) $ 126,400 $ 764,800 $ 891,200
GWT-1B(1,00 gpm) $ 225,900 $1,239,600 $1,465,500
GWT-1B1 (300 gpm) $ 108,300 $ 751,300 $ 859,600
GWT-1C(400 gpm) $ 0 $ 256,600 $ 256,600
GWT-2(400 gpm) $1,017,500 $ 957,400 $1,974,400
GWT-2(1,000 gpm) $2,033,900 $1,417,300 $3,451,200
GWT-3(400 gpm) $ 930,000 $1,254,500 $2,184,500
GWT-3(1,000 gpm) $1,802,500 $2,836,000 $4,638,500
GWT-4(400 gpm) $ 284,000 $1,066,90'0 $1,350,900
GWT-4(1,000 gpm) $ 511,000 $2,339,200 '$2,850,200
GWT-5(1,000 gpm) $ 265,700 $ 282,600 $ 548,300
soil Treatment Alternatives
The estimated present worth of the soil alternatives are shown
below.
Alternative Capital O&M Present Worth
5-1 $ 0 $ 0 $ 0
5-2 $ 133,000 $ 76,900 $ 210,200
5-3 $ 8,325,000 $ 0 $ 8,235,000
5-4 (A) $ 193,750 $286,500 $ 480,250
S-4(B) $ . 416,250 $ 0 $ 416,250
5-5 $10,575,000 $ 0 $10,575,000
5-6 $ 625,000 $ 42,400 $ 667,400
5-7 $29,243,800 $ 42,400 $29,286,200
state Acceptance: The state of Ohio concurs with the selected
remedial alternative. A letter from the OEPA indicates this
\ support.
community Acceptance: U.S. EPA solicited input from the community
on the Proposed Plan for the Zanesville Well Field site. Verbal
comments received during the public meeting indicated full
support of the selected remedial alternative. written comments
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39
received during the public comment period also indicated full
support of the selected remedial alternative..
x.
THE SELECTED REMEDY
u.s. EPA believes the preferred alternative as described in the
Record Of Decision of GWC-3, GWT-1B, GWT-1C, S-4, and S-6 is the
most appropriate solution for the remediation at the Zanesville
Well Field Site because of its performance against the nine
evaluation criteria previously discussed. The major components
of the selected remedy include the following:
Pre-Design Work;
Groundwater Containment (Modified GWC-3 - installation of
additional interceptor wells if required after further
study); .
Groundwater Treatment Alternative
meeting BAT requirements of OAC
additional wells are installed,
stripper); .
Organic Soil Remediation Alternative S-4(A) (in-situ vapor
extraction (ISVE»; and .
Inorganic Soil Remediation Alternative S-6 (soil washing).
The exact number of interceptor wells needed to completely
capture/contain the plume of TCE and DCE and me~t groundwater
clean up objectives within a rapid time frame will be determined
in pre-design. Following pre-design, it. will be determined
whether less or more than two additional interceptor wells will
be needed. The u.S. EPA has identified the potential need for
additional interceptor wells based on the results of the
groundwater model. Since additional information is required to
increase the accuracy of the model, it cannot be determined at
this time if the existing four interceptor wells and the two city'
interceptor wells are completely containing. the plume of TCE and
DCE, and will meet the groundwater clean up objectives within a
rapid time frame Therefor, u.S. EPA has chosen a modified GWC-3
Alternative, which requires that after the pre-design study is
completed, the necessity, the number of interceptor wells and the
location of the wells will be determined.
*
*
*
GWT-1B (air stripper
3745-31-05) only if
with GWT-1C (existing
*
*
The capture/containment system will be evaluated yearly to
determine the systems effectiveness. The u.S. EPA will determine
based on the results of the evaluation if any modifications of
the capture/containment system are required in order to ensure
complete capture of the contaminate plume and if the system will
meet the groundwater clean up objectives within a rapid time
frame. .
The groundwater capture/contain system will continue to operate
until the MCLs and health based clean up standards of all the
chemicals of concern have been met.
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40
Institutional Controls such as fences will be used to restrict
access to the UTA facility, the city interceptor wells and their
discharge pipes. (Deed restrictions will be sought to control
future use of the UTA facility until soil clean up levels have
been met and to control the use and placement of wells in the
affected area until groundwater cleanup levels have been met.)
Additional groundwater monitoring wells will be installed east of
the city interceptor wells to determine if a source of
contaminants other than those attributable to UTA's facility are
entering the city well field. Available data indicates that the
major source of VOCs is from the UTA facility. However, there
are some data gaps on the east side of the well field. The
additional wells will identify if there are.other sources of
contaminants entering the city well field.
The appropriate size air stripper was chosen to treat the total
flow rate from GWC-3. Any new air stripper constructed at the
site (i.e. on UTA's property or in the well' field) must be
evaluated pursuant to the BAT requirements in OAC 3745-31-05 to
determine air emission controls requirements.
Discharge from Interceptor well I-1 will require additional
treatment if it fails to meet the state of Ohio discharge
standards, which meet the substantive requirements of an NPDES
permit. Discharge from the city interceptor wells will require
additional treatment if it fails to meet the state of Ohio
discharge standards, which meet the substantive requirements of
an NPDES permit.
The soils contaminated with VOCs will be treated with ISVE. The
extracted vapors will be treated using carbon absorption. The
soils contaminated with inorganics will be treated by soil
washing. The clean soils may be replaced in the ground. The
concentrated waste and filter cake will be taken off site for
further treatment/disposal.
cost ot Selected Remedial Alternative:
Alternative caDital Cost O&M (PW) Present Worth
GWC-3 $ 75,000 $ 602,000 $ 677,000
GWT-1B (400 gpm) $ 126,400 $ 764,800 $ 891,200
GWT-1C $ 0 $ 256,600 $ 256,600
S-4(A) $ 193,750 $ 286,500 $ 480,250
S-6 $ 625,000 $ 42,400 $ 667,400
TOTAL $1,020,150 $1,952,300 $2,972,450
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41
XI.
STATUTORY DETERMINATIONS SUMMARY
1.
Protection of Human Health and the Environment
The selected remedy provides a sufficient degree of overall
protection of human health and the environment, by
containing/capturing the groundwater contamination plume,
restoring the aquifer to MCL cleanup levels, treating the soils
and any source to prevent additional groundwater contamination,
treating the soils to prevent human exposure to contaminated
soils, and minimizing contaminant air emissions. Institutional
controls will be implemented during remediation to assure
protection until confirmation sampling and analyses indicate that
a health based clean-up has been achieved. .
2.
Attainment of ARARs
The selected remedy will attain all Federal and state applicable
or relevant and appropriate requirements as described in section
IX of this Record of Decision. In addition, the selected remedy
will attain all Federal and state "To Be Considered" requirements
as described in Section IX of this Record of Decision.
The following specific ARARs will be met by the selected remedy:
Air
ORC Chapter 3704 provides statutory authority for the regulations
of air pollution control in the State of Ohio. The Ohio EPA air
pollution control regulations developed on the basis of Chapter.
3704 of the ORC can be found in Chapters 3745-15 to 3745-26, .
3745~31, 3745-35, 3745-71, 3745-73 and 3745-75.
Groundwater
Maximum contaminant Levels (MCLs) and Non Zero contaminant Level
Goals (MCLGs) established under the Safe Drinking Water Act
(SDWA) in 40 CFR 141 and 56 Fed. Reg. 3526.
Surface Water
National Pollutant Discharge Elimination System (NPDES)
Requirements
ORC Chapter 6111 establishes Ohio EPA's authority to set water
quality standards and to regulate water pollution sources.
Regulations developed and implemented by Ohio EPA under the
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42
authority contained in ORC Chapter 6111 are in part, found at OAC
Chapter 3745-1-03 through 3745-1-07, inclusive, 3745-1-24,3745-
31-05, 3745-32-05 and 3745-33-05.
soil
~CRA Land Disposal Restrictions (40 CFR 268)
ORC Chapter 3734 provides statutory authority for the regulations
of solid and hazardous waste activities in the state of Ohio.
The Ohio EPA hazardous waste regulations developed on the basis
of Chapter 3734 of the ORC can be found in ORC Chapters 3745-50
to 3745-59.
It may be noted that the selected alternative may involve sending
materials excavated from the site to an off-site landfill. These
activities will be conducted in compliance with the u.s. "EPA Off-
Site policy (OSWER Directive No. 9834.11) and Section 121. (d) (3)
of SARA.
3.
Cost-Effectiveness
The selected remedy provides overall cost-effectiveness because a
high degree of permanence is achieved by treatment, via pumping
and treating the groundwater, treating the soils and any sources,
and treating the air emissions. The selected soil remedy can be
implemented at a cost far less than complete off-site disposal,
off-site incineration, or in-situ vitrification. Although soil
washing is slightly more costly than limited off-site disposal
for the treatment of the inorganic contaminated soils, soil
washing provides for reduction of volume through treatment.
Limited"off-site disposal does" not provide for any treatment.
4. utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum
Extent Practica~le "
The selected remedy provides the best balance with respect to the
nine evaluation criteria as described in section IV of this
Record of Decision. Permanent solutions are obtained through a
combination of groundwater restoration using interceptor wells
and complete treatment of all soil contaminants and any source
(preventing additional groundwater contamination), using ISVE and
soil washing. Treatment technologies are utilized to the maximum
extent practicable by treating the air emissions of any new!y
required air strippers and air emissions of the ISVE, treating
both the organic and inorganic soil contaminants using ISVE and
soil washing. .
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43
s.
Preference for Treatment as a Principal Element
The selected remedy eliminates the principal threats at this site
by the use of treatment, via ISVE of the organic contaminated
soils and soil washing of the inorganic contaminated soils. The
selected remedy also treats any new air emission using activated
carbon filters.
XII.
DOCUMENTATION OF SIGNIFICANT CHANGE
Section 117(b) of CERCLA requires that the final remedial action
plan be accompanied by a discussion of any significant changes in
the Proposed Plan. The selected remedy as described in this ROD
is the U.S. EPA final remedial action plan for this site. The
U.S. EPA has determined that there are no significant changes
from the Proposed Plan.
The Responsiveness Summary attached hereto addresses the public
comments received during the 40 day public comment period on the
Proposed Plan.
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Table 1.
Summary of Calculated organic and Inorganic soil Clean Up Levels
Organic Constituent
Clean Up Level
DDb
TCE
6.3
cis-DCE
34.3
trans-DCE
59.0
Inorganic Constituent Clean Up Level
mg/ka
Barium 77
Cadmium 4
Copper 315
Lead 12
Manganese 771
Mercury 3
Zinc 1,410
-------
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APPROXIMATE SCALE IN FEET
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-------
A1TACHMENI' 1
ErnlJENI'LIMITATIONS - ZANrSVILLE SITE
A. 1 Effluent Limitations - Outfall - 001
(ff;.UENT CHARACTERISTIC DlSOtARGE LIMITATIONS fiOI I TOR I NG
Con--Anfr..-t I on Loedl nt- R£OU IREMENTS
IWpoI"t I ng Oth8r Units (Sp8cJfy) kgld8y MMs. S.I.
Code UN I TS PARAMETER SO cI.y Dally M.x. SO day Dally Max. Fr-tIQ. Twe
00550 JG/L ..,I., Tot.-
Monfllfer.le 50 .., 83' 208 IlMaftth &rib
~ HG/I. 011 ~d ......, Tot.1 15 20 8 91 II'Marrtt. erAb
00719 tell Cyen i., free - /MCIn'ttI er.&,
010'2 UGIl Coppe,., Tot.1 - /MCIn'ttI ,,..
0104' ueIl Iron, Tot. I 11Mon1'tl. 6,.-
01077 U$/l SII-.r, To+.1 IlMon1'tl Cr-
~1092 UGIl Zinc, Tot.1 53' Z.~3 l/Month ,...&,
,..546 UGlL 1,2-Tr.ns-DJchloro8thylent
Tot. I 25 66 0.01. 0.50 11Mon'"- Cr.a.
39180 UGIL T r i dllol"08thy lent,
Tot.. 26 69 0.012 0.51 I IMcInth &r.b
50050 MSD fl. Rrie D811V 24 Hr. Tot. I
71900 U;/I. "*rcury . /Month C,.8b
. Effluent loading limitations have b.en est&bliah.d u.lnt a flow value of
1.2 HGD.
B.l. Th~ pH CReportinc Code 00400) shall not b. 1... than 6.5 S.U. nor creater
than 9.0 S.U. and shall be monitored l/month by ~rab sample.
-
-------
-
-- -
A.2 Effluent Limitations - CX1tfall - 002
ttEI.UE1fT 04AAACTEIUST'C DISCHARGE l'MIT~rIONS ~~
Canc:8ntr.t I on loedi n~ REOU I RfIllfNTS
R.pcri i '" ' Other Units (Specify) kg/.s.y ....s. S8sIple
Cod. UN ITS ftARAM£TER 50 d.v Dallv M.x. 50 d8v 0.1 Iv ~. 'rea. TVD8
00530 8ClL Re.idue, Tot.,
Nonfllterabl. 50 4' " 103 1/Mon+tI 4ir.
00550 8&IL 01' end $roM-, 1crt.1 15 20 ]4 46 l/Month Gr.
G07" Mill Cyen'., rree IIMortttI era
Olo.u U6IL Copper, Tcrt.1 ,/Month Sr.b
01~5 UGIL Iran, Tot.1 IIMortttI Srab
0.077 UGIL Silver, TCIt.' IIMon1'h C,..
01~2 UGIL Z~ftC, Tcrt.1 555 1.22 ' IMon11'i 'rab
S4~ UGlL ',2-Tr.ns-Olchloro.thyt.ne
Tot. I 25 1;6 0.057 0.1' 8/Month Grab
"'SO uri/L TrlchlorGeihy'.ne,
Tot. I 26 69 0.059 0.16 l/Month Grab
50050 N;D F' I CIiI RIte o.lly 201 Hr. Tot..
71900 U8IL "'rClUry l/Month Gr.
* %ffluent 10841n& limitatIon. have bean establiShed usial 8 flow value of
').604 JlGD.
1.2. the pH CReportlnl Code OO~OO)'lhall not be less than 6.5 S.U. nor Iraatar
than 9.0 S.U. and shall b. monitored l/month by crab sample.
-
-------
.~
.;
A.3 Effluent Limitations - Outfall 003
£m.uEWT ~ISTIC DISCHARGE LIMITATIONS tPlITORIH6
Conc8n'trMtian a.o.d I nG* REOU I REMOn'S.
...... i lit Other Unit. (Sp8clfy) "I/o.y "'.1. s.pl.
~ UNITS pAIW'ETER 50 o.v o.lIv Ma". 50 o.v Dai Iv MP. fNQ. Twe
00550 f51L .,idue. Tcrtal
Ilanfllter-.l. 30 e 58 87 IIMonttI Sr-
00550 tGIl 011 and 8,...... Tcrt.1 15 2D 2t " l/Month &rab
00719 Ml81L Cyan I.. ,,.. I /MoIIth Qreta
0100U USIL eopp.r. Tcrt.1 l/Month $rib
010.5 UGIL Iron. Total - l/Month erab
01077 USIL Sliver. Tcrtal l/Month Cr.
01092 UliIL Zinc. Tot.1 5" 1.03 l/Month 8r.
3Cs.6 u&Il 1.2-Traftl-Dlehloro8thylene
Tcrtal 25 " 0.0&8 0.13 1 /Month Crab
39180 UGIL Trichloroethylene.
Tote I 26 69 0.050 0.13 1/MonttI ..ab
50050 - fl. Rete 0.1 ty 24 Hr. Teri.1
71900 UGIL Mercury IIMon'I'b 5r'eb
4tfo
. Bff1uent limitations bave been e.tablished udns a flow value of 0.510 HGD.
B.'. tbe pH (Reportlns Code 00400) eball Dot be less tban '.5 S.U. nor sreater
than 9.0 S.U. and shall be monitored l/month by srab sample.
Outfall 001 samples shall be taken of sroundwater from Interceptor Well.
11, 12, 13 and 14 (on the east side of United Technolosies Automotive'.
property), after air strippins and before discharse into the Kuskinsum
aiyer.
Obtfall 002 samples of city well W-6 contaminated. sroundwater shall be
t1ken at final point of discharse to the Kuskinsum River.
Outfall 003 samples of city well W-12 contaminated sroundwater shall be
taken at final point of discharse to the Kuskinsum River.
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. M
-
Effluent limitations may be revised in order to meet vater quality
standards afte~ a stream use determlnation and vasteload allocation. are
completed and approved. These limitations and discharse requirements may
be modified to comply vith any applicable vater quality effluent
limitations. .
1;
~ecial Conditions:
!he effluent shall, at all times, be free of substances:
A.
In amounts that viII settle to form putrescent, or otherwise.
objectionable, sludse deposits; or that viII adversely affect
aquatic life or vater fowl;
B.
Of an oily, sreasy, or surface-active nature, and of other floatins
debris, in amounts that will form noticeable .ccumulations of scum,
foam or aheen;
c.
In ~ounts that will alter the natural color or odor of the
receivins water to such desree as to create a nuisance;
D~
In amounts that either sinsly or in combination vitb otber
substancel are toxic to buman, animal, or aquatic life;
E.
In amounts that are conducive to the srowth of: aquatic weeds or
alsa8 to the extent that such srowths become inimical to more
desirable forms of aquatic life, or create conditions that are
unsightly, or constitute a nuisance in any other fashion;
F.
In amounts that will impair delisnated instream or downstream water'
uses.
Samples and measurements taken as required herein shall be
representative of the volume and nature of the monitored flow. Test
procedures for the analysis of pollutants shall conform to resulation
~o eFR 136, "Test Procedures For the Analysis of ?ollutants" unless
other test procedures have been specified in this permit. Also
periodically calibrate and perform maintenance procedures on ail
monitorins and analytical instrumentation at intervals to insure
accuracy of measurements.
-
-------
..
_.~. --- 4-
- - ......-
-
Definitions:
A. The "daily load limitation" i8 the total discharse by weisht durins
an, calendar day. If only one sample i8 taken durins . day, the
weiSht of pollutant di8charse calculated from it is the daily load.
B. !be wdailvconcentration limitation" .eans the arithmetic averase
of all the determinations of concentration made durins the day. If
onl, one sample is taken durins the day, it. concentration is the
daily concentration~
C. 1'I1e -30-dav load limitation- i8 the total d18charce by weisht
durins any 30-4ay period divided, by the number of days in the
30-4ay period that the facility was in operation. If onl, one
8ample 1. taken in a 30-4ay period, the weisht of pollutant
dbcharse calculated from it is the 30-4ay load. If more than one
sample 18 taken durins one 30-4ay period, the 30-4a1load i8
calculated by determinins the daily load for each da, 8ampled,
total inS the daily loads for the 30-4ay period and dividinS by the
DUmber of days sampled.
D. The -30-dav concentration limitation" .eans the arithmetic averese
(weiShted by flow) of all the determinations of daily concentration
made durins the 30-day period. If only one sample is taken durins
. the 30-4ay period, 1t. concentration 1s the 30-4ay concentration
for that 30-4ay period.
.
I. Absolute limitations. Compliance with limitations havins
descriptions of "shall not be Ie.. than," "nor sreater than,-
"sball not exceed," "minimum,- or "maximum" shall be determined
from any sinsle value for effluent samples and/or measurements
collectad.
F.
1. -KGD" means million sallons per da7.
2. "m~/l" means mUlisrams per liter.
3. "u~/l".means microsrams per liter.
G.
"Bypass" means the intentional diversion of waste. from any portion
of a treatment faeility.
H.
"Severe ~ro~erty dama~e" means substantial physical damace to
property, damase to the treatment facilities which would cause them
to become inoperable, or substantial and permanent loss of natural
resources which can reasonably be expected to Occur in the absence
of a bypass. Severe property damase does not mean economic loss
caused by delaY8 in production.
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zanesville Well Field Site
Zanesville, ohio
..........................
Responsiveness Summary
Introduction
The United states Environmental Protection Agency (U.S. EPA), the
Ohio Environmental Protection Agency (OEPA) and United Technologies
. Automotive, Inc (UTA) entered into a Consent Order whereby UTA
agreed to undertake a Remedial Investigation and Feasibility Study
(RIfFS) at the Zanesville Well Field Site. The RIfFS activities
have been completed. Information was collected on the nature and
extent of contamination at the Zanesville Site Well Field (RI) and
alternatives for appropriate remedial action at the Zanesville Well
Field Site were developed and evaluated (FS and Proposed Plan).
Throughout this process, public meetings have been held near the
site at which U.S. EPA and OEPA were available to discuss the RIfFS
and exchange information with the public. At the conclusion of the
FS, a Proposed Plan was finalized by,U.S. EPA in consultation with
OEPA, which recommended an alternative for remedial action at the
Zanesville Well Field Site. U.S. EPA conducted a 37 day public
comment period on U.S. EPA's Proposed Plan and FS from August 8,
1991 to September 16, 1991. On August 15, 1991, U.S. EPA' presented
its Proposed Plan for the Zanesville Well Field Site at a public
meeting. .
The purpose of this responsiveness summary is to document the
comments received during the public comment period, and the U.S.
EPA's responses to the comments. All of the comments summarized in
this document were considered prior to U.S. EPA's final decision
embodied in the Record of Decision for the Zanesville Well Field
Site.
The responsiveness summary is divided into the following sections:
. .
I. Responsiveness Summarv Overview. This section briefly
outlines the proposed remedial alternatives as presented in the
Proposed Plan, including the recommended alternative.
II. Summarv of Public Comments Received Durina the Public Comment
and U.S. EPA Responses.
1.
Responsiveness Summary Overview
On August 10, 1991, U.S. EPA submited the FS and the Proposed Plan
for the Zanesville Well Field Site to the public for review and
comment. The alternatives for remedial action described methods
for cleaning the contaminated groundwater, soils and any source
areas. U.S. EPA's Proposed Plan described four groundwater
containment alternatives, five groundwater treatment alternatives
and seven soil remediation alternatives. The proposed remedial
alternatives included the fOllowing:
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Groundwater containment
- No action
Existing Interceptor Wells
Two Additional Interceptor Wells
Five Additional Interceptor Wells
Groundwater Treatment
- No Action
Existing Air Stripper
Additional Air Striper No Emission
Control
Additional Air stripper Emission Controls
UVjOxidation Treatment
Biological Treatment
Activated Carbon Treatment
Air Stripper in City Well Field
Soil Remediation
- No Action.
Multi-media Cap
Off-site Landfill Disposal of Soils
In-Situ Vapor Extraction of Soils
Limited Excavation and Off-site Disposal
Off-Site Incineration of Soils
Soil Washing
In-Situ Vitrification of Soils
After careful evaluation of the RI and FS the U.S. EPA recommended
the following remedy:
*
*
Pre-Design Work;
Groundwater Containment (Modified GWC-3 - installation of
additional interceptor wells if required after further
study);
Groundwater Treatment Alternative GWT-1B (air stripper
meeting BAT requirements of OAC 3745-31-05) only if
additional wells are installed, with GWT-1C (existing
. stripper) ;
Organic Soil Remediation Alternative S-4(A) (in-situ
vapor extraction (ISVE»; and
Inorganic Soil Remediation Alternative S-6 (soil
washing). . .
*
*
*
II.
SUMMARY OF COMMENTS RECEIVED DURING PUBLIC COMMENT PERIOD AND
U.S. EPA'S RESPONSE TO COMMENTS.
Comments raised during the Zanesville Well Field Site Proposed Plan
public comment period are summarized below.
1) Comment Mike Wyatt - citizen
More groundwater monitoring wells should be installed and sampled
on the eastern side of the well field in addition to the monitoring
wells proposed by U.S. EPA. These wells will help to determine if
any additional contamination is entering the well field from
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sources other than UTA's source of contamination. Prior to House
Bill 592 the well field was completely surrounded by landfills.
The additional wells are required to determine if there is an
additional source of contamination to the well field. .
1) ResTJonse
The exact number of groundwater monitoring wells required to assess
any additional sources of contamination was not determined in the
proposed plan. U.s. EPA determined that the most appropriate time
to determine the number of wells required is during the development
of the work plan to perform the Remedial Action. U.s. EPA will
require enough monitoring wells to adequately determine if there is
an additional source of contamination to the well field.
2) Comment Philip Schutte - citizen
The addtion of three interceptor wells (in addtion to the
interceptor wells required in the Proposed. Plan) on the UTA side of
the river would lower the water table. This would force
contaminated groundwater back to the UTA facility preventing it
from crossing under the river into the well field. The three
additional wells should be placed as close to the abandoned well as
possible, or where ever the highest concentration of the
contaminant is found.
2) Response The U.S. EPA recommended containment al ternati ve
allows for as many interceptor wells as is required to completely
contain the plume of contamination and restore the aquifer in a
rapid restoration time frame. After the completion of the pre-
design study, U.s. EPA will be able to determine the exact number
and location of interceptor wells required. The interceptor wells
will prevent additional contamination from crossing under the
river.
3) Comment Doyle strain - citizen
The U. S. EPA recommended al ternati ves should be taken, and the
suggested actions would appear to correct the contamination as well
as possible. The old Zanesville landfill should be. surrounded with
moni toring wells. The residents of Zanesville deserve to know what
is leaching from the old Zanesville landfill to the groundwater and
the direction of its migration.. .
3) ResTJonse
The U.S. EPA recommended alternative requires groundwater
monitoring of the eastern side of the well field to determine if
additional contaminants are entering the well field. If it is
determined that there is another source of contamination to the
well field, the location of the source will be investigated.
4) Comment - Frederick J. Grant III, PE. PS.
Public Service Director, City of Zanesville
signs and Fencing. The City has maintained warning signs at each
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well discharge to the Muskingum River since 1981. In addition, the
City has generally isolated the area by blocking off the access
road, chain link fencing and gates, wooden guard posts and
extending discharge piping well away from the river bank. The City
has not fenced individual discharge points because they would
collect debris during normal seasonal rise and fall of the river
creating a maintenance problem.
The City has not experienced a problem with intrusion into these
areas in the past, and feels addi tional fencing measures are
unnecessary.
Additional Monitoring Wells. During the initial investigations by
the City for the source of pollution, the City installed monitoring
wells toward the old City owned landfill. These wells showed no
evidence of contamination from the old landfill and were removed.
The old landfill was owned and operated by t~e City and used to
landfill domestic municipal. waste not industrial or commercial
waste and was closed in the late 1960's. Any leachate discharge
would be. 1200 feet down stream from the polluted well #6. The
leachate drains over land directly to the river and not into the
aquifer because of the relative impervious overburden in this area.
The. City is not aware of any leachate problems from this old
landfill either now or during the time it was active.
The City feels monitoring the old landfill
remediation program would be a waste of funds.
as
part
of
the
Interception by 2 Municipal wells. currently, the City plans to
utilize only one municipal well for interception. Existing levels
of pollution are such that operation of one well will prevent any
migration of pollution northward. Levels of pollution have fallen
dramatically since 1981 in the south end of the well field and
modeling studies indicate one active well in this area will be
adequate to prevent migration.
4) ReSDonse
Signs and Fencing. At a number of the public meetings, citizens
have expressed concern to u.s. EPA that the waste water discharge
pipes are located within a public park and that there is nothing to
restrict access to the pipes. Several citizens stated that they
have seen children swimming directly below the outfall of the
pipes. Therefore, U~S. EPA is still very concerned that the access
to the pipes be restricted. u.s. EPA is aware of the maintenance
problems of installing a fence on the banks of a river that floods.
Therefore, the ROD may allow other devices, in lieu of a fence,
that will restrict access to the outfall but not have the same
maintenance problems. However, if other devices fail to prevent
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access, U.S. EPA will require fencing and it's required periodic
maintenance as a requirement of the remedial action
Additional Monitoring Wells. In every public meeting, citizens of
Zanesville have expressed concern over the possibility that the old
Zanesville landfill may be adding contaminants to the City Well
Field. Currently, there are no groundwater monitoring wells in the
area which could detect contamination coming .from the direction of
the old landfill. Because of a lack of laboratory quality
assurance documentation of UTA's groundwater data collected before
U.S. EPA's involvement, U.S. EPA was not able to use the data to
make decisions on remediation~ Likewise the data collected by the
City of Zanesville does not have the laboratory quality assurance
documentation required to make decisions on remediation. Therefore
the additional monitoring wells will be required.
Interception by 2 Municipal Wells. U.S. EPA agrees with the City
of Zanesville that the levels of pollution have fallen dramatically
since 1981. There are still high concentrations of TCE .of up to
1400 ppb within the well field. These high concentrations may
present an imminent and.substantial endangerment to public health.
After extensive studies, U.S. EPA had determined that wells 6, 12,
and possible well 7 will be required to be used as iriterceptor
wells in order to completely contain the plume of TCE and DCE and
remediate the aquifer in a rapid restoration time frame. The use
of these wells as interceptor wells is considered a part of the
Remedial Action selected by U.S. EPA.
U.S. EPA will allow identified potentially responsible
parties(PRPs) the opportunity to enter in to an agreement with U.S.
EPA to undertake the Remedial Design and Remedial Action (RD/RA).
Should the PRP elect not enter into an RD/RA agreement with U.S.
EPA, U.S. EPA may order the PRPs under section 106 of CERCLA to
design and implement the RA, and/or use Superfund monies to design
and implement the RD/RA and later seek to recover these monies from
the PRP. Currently, UTA is the only party U.S. EPA has identified
as a PRP.
5) Comment
Julie M. Walawender, Senior Environmental Services
Specialist, united Technologies Automotive, Inc.
Potentially Responsible Party (PRP)
GROUNDWATER CONTAINMENT Alternative GWC-3 was recommended by U.S.
EPA since, "it cannot be determined at this time if the existing
four interceptor wells and the two city interceptor wells are
completely containing the plume of TCE and DCE." (p. 29 of the
Proposed Plan). This possibility was documented as requested by
U. S. EPA throughout the FS, which led to the agreement for
additional data collection to better define the existing
ground-water capture zone. Therefore, selection of a particular
number of interceptor wells is premature. U.S. EPA's containment
alternative is termed "modified" (p. 29) based on the appropriate
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number of interceptor wells, and the selected remedy under this
scenario could actually become Alternative GWC-2 (utilize existing
interceptor wells). The ROD should be explicit regarding the
potential for pre-design data to alter the selected remedy.
GROUNDWATER TREATMENT Air stripping treatment for interceptor
Well I-1 contingent upon revised NPDES limits was developed in
the FS (po 95). In the June 27, 1991 letter from Paul Novak of
the Ohio Environmental Protection Agency to UTA, the proposed
30-day average NPDES limits for TCE and 1,2-DCE were 26 ug/L and
25 ug/L, respectively, based on an average flow rate of 1.15
million gallons per day (about 800 gallons per minute). Given the
sample variability over time, it appears that the existing air
stripper will not consistently meet the proposed limits.
However, as a result of source control action (vapor extraction),
the mass loading to the aquifer may be significantly reduced.
Therefore, an evaluation should be conducted regarding the
predicted mass loading to the air stripper while the vapor
extraction system is operating. Such an evaluation should occur
after completion of the vapor extraction design test to det~rmine
if the existing stripper tower (in combination with soil vapor
extraction) can meet the revised discharge limits.
According to the Proposed Plan, air emission controls
(activated carbon) are required for the proposed groundwater
treatment system at UTA, "because of state emission limits"
(page 29). Specific air discharge limits were not available
(identified as ARARS) at the time the FS was prepared. The
current permitted discharge rate is 20 lbs/day, which is being
consistently met by the existing air stripper. Table 25 of the FS
provides estimated mass emission rates to the atmosphere for
various groundwater flow rates. Using average influent
concentrations of trichloroethylene and dichloroethylene, these
calculations indicate that the maximum mass loading to the
atmosphere would be about 10 lbs/day (assuming a groundwater flow
rate of 1,500 gallons per minute). It is not known whether the
state emission limits referred to in the Proposed Plan relate to
a revised numerical standard, a requirement for emission controls
regardless of the nature of the source, an assumed discharge rate
from a new source based on particular design assumptions, or some
other factor. Regardless of the reason, U.S. EPA and/or Ohio EPA
should explain this statement prior to issuance of the ROD, since
it potentially represents an ARAR which was not identified during
the FS process.
SOIL TREATMENT FOR INORGANIC CONSTITUENTS OF CONCERN Soil
washing (alternative 5-6) was recommended by U.5~ EPA presumably
due to the additional treatment afforded by this technology.
relative to off-site disposal in a landfill. Since the Agency
determined that remediation of hot spots at depth was required
(as a result of the residential exposure scenario), the FS
included recommendations for additional soil borings and sampling
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(pps. 40, 130) in order to better define the actual volume of
soil requiring reme~iation. This data may indicate that the
volume is significantly less than 1,800 yd3, -as assumed in the
FS. In addition, it is likely that most of the affected soil
could be disposed of as non-hazardous waste. These two factors
(reduced volume and lower disposal cost) could significantly
reduce the cost excavation and off-site disposal. For example,
the estimated cost for disposal of 1,800 yd of non-hazardous
waste is $20-S0/yd3 compared to $140-200/yd3 for the same volume
of hazardous waste. The ROD should contain language which
acknowledges the need for the collection of additional soil
samples for inorganic constituent analysis and should outline-the
general criteria for potential remedy changes. Such criteria
should include the percent change in the assumed soil volume -
requiring disposal or treatment which would require revisiting
the detailed analyses in the FS. Documenting decision criteria
in the ROD is critical, to allow the flexibility necessary to
make changes in the remedy as additional data warrants.
In addition, the FS and the Proposed plan both indicate concerns
regarding the feasibility of soil washing. This is due, in part,
to the very limited number of available vendors for this -
technology. Technical feasibility is further weakened due to the
small amount of soil to be treated. Above-ground soil washing
systems are normally feasible for a minimum 20,000 yd3 of
material. The average throughput of soil washing systems is 20
tons per hour. Therefore, if the technology were applied to the
small volume of soil (approx. 1,800 tons) at UTA, very little
time would be available to fine tune the system, which could lead
to reprocessing and other system inefficiencies. It may also be
difficult to locate a vendor interested in bidding on such a
small scale job.
SOIL CLEAN-UP LEVELS
Table 1 of the Proposed Plan lists calculated cleanup levels for a
residential exposure scenario. However, these numbers differ from
the levels calculated in the FS (Tables 13 and 16). It is unclear
how the cleanup levels in the Proposed Plan were calculated. Based
on the levels indicated in the Proposed Plan, several inorganic
chemicals assumed to be constituents of concern in the FS should no
longer be considered for remediation (barium, cadmium, copper,
manganese, and zinc), since the maximum detected concentrations of
these constituents (Table 11 of the FS) are below U.S. EPA cleanup
levels. The use of the proposed cleanup levels provides additional
support for excavation and off-site disposal since the volume of
soil requiring remediation will be substantially smaller than
assumed in the FS.
ADDITIONAL MONITORING WELLS UTA agrees that the installation of
additional groundwater monitoring wells east of the city
interceptor wells may provide useful information about additional
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sources of contamination. However, since the purpose of these wells
is to determine if a nearby landfill is affecting city wells (and
to alleviate public concern). UTA cannot commi t to bear the
financial responsibility for their installation. .
5) ResDonse
Groundwater containment. The Proposed Plan stated that the exact
number of interceDtor wells needed to completely capture/contain
the plume of TCE and DCE and meet the groundwater clean up
objectives within a rapid time frame will be determined in Dre-
desiqn (emphasis added). For RA cost estimation, purposes U. S. EPA
identified the expected number of wells. U.S. EPA identified the
potential need for additional wells based on the results of the UTA
developed groundwater model which predicte~ that the plume was not
being completely contained and that the groundwater clean up
objectives would not be met within a rapid time frame, and observed
site conditions which suggested that the existing interceptor
system may not meet the groundwater clean up objectives within a
rapid .time frame. .
Groundwater Treatment. U.S. EPA in consultation with OEPA, would.
consider making a determination concerning the effects of the ISVE
system on the loading of the air stripper. If it can be
demonstrated that after the completion of the ISVE pilot test and
one year of implementation of the full-scale ISVE system, the
existing stripper tower in combination .with ISVE can meet the
discharge limi ts contained in the ROD; then the U. S. EPA in
consultation with OEPA, may allow treatment of the water from well
I-l using an equal or superior technology (in place of air
stripping) which would meet discharge limits contained in the ROD.
The. air emissions of any new air strippez: constructed on the
site(i.e. on UTA's property or in the well field) must be evaluated
pursuant to the BAT requirements outlined in OAC 3745-31-05 prior
to the determination that air emission controls are required. This
ARAR was identified in the FS process.
soil Treatment For znorqanic Constituents of Concern. The FS
included recommendations for additional soil borings and sampling
because of an inadequate number of soil borings and sampling during
the 'RI which resulted in data gaps. Although it may also be true
that additional sampling will indicate that the volume is
significantly less than 1,800 yd3 as assumed in the FS it may also
be true that additional sampling could indicate a significant
increase in the volume of soils to be treated(over 1,800 yd3).
Neither the FS nor the comment from UTA suggest any scientific
reason why the volume of soils could be less than 1,800 yd3. During
the review of the RI U.s. EPA presented UTA with a scientific set
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of calculations that can be used to estimate the depth to which
soils should be cleaned up. This calculation demonstrates that the
depth to which soils should be cleaned may be deeper than what the
FS assumed.. Therefore the total volume of soils required to be
treated could be well above 1,800 yd3. UTA also does not give any
data to support the assumption that most of the affected soil could
be disposed of as non-hazardous waste instead of hazardous waste as
the FS determined. Therefore U.S. EPA has no bases to modify the
recommended alternative of soil washing based on percent change of
soil volume requiring treatment.
The feasibility of soil washing is considered fair not infeasible.
It is considered fair because of a limited number of venders and
the volume of soil to be treated. There is a limited number of
venders due to fact that soil washing is a relatively new
innovative technology. The number of venders will most likely
increase in the future. Since soil washing may not be implemented
for ten years, there should be a greater number of venders
available at that time. A carefully conducted and controlled soil
washing pilot test stUdy, should be able to fine tune the soil
washing system. This should prevent the reprocessing of the soils
and limit other system inefficiencies.
Soil Clean Up Levels UTA's comment notified U. S. EPA that the
Proposed Plan contained typographical errors concerning the
calculated clean up levels based on residential child direct
contact, ingestion, or inhalation. The errors were contained on
Table 1. The text of the Proposed Plan on page 11 did contain the
correct clean up level based on residential child direct contact,
ingestion, or inhalation ("The soil clean up level for the
inorganic chemicals of concern represent concentrations which yield
a cumulative hazard index less than 1, and the cumulative excess
lifetime cancer risk (ELCR) less than 1X10-6.,,). Table 1 only
summarized calculated soil concentrations that achieve the soil
clean up levels. In fact the actual clean up concentration for the
soil contaminate may change after the soils remediation as long as
the over all risk yield a cumulative hazard index less than 1, and
the cumulative excess lifetime cancer risk (ELCR) less than 1X10-6.
ADDITIONAL MONITORING WELLS U. S. EPA has determined that the
additional monitoring wells are necessary for the RA. The party
that is responsible for the installation and sampling of the wells
does not concern the selection of the remedy, therefore, there is
no response to this comment.
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