United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R05-89/109
September 1989
$EPA
Superfund
Record of Decision
Wausau Water Supply, Wl
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50272-101
REPORT DOCUMENTATION i. REPORT NCX *
.PAGE. EPA/ROD/R05-89/109
• •4. TltlaandSdbtJtta
.. SUP ERFUND .RECORD OF DECISION
Waus.au- Water Supply, WI
Second Remedial Action - Final
7. Author<«) . .
9. Performing Organization Name and Address
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M 'Street, S.W.
Washington, D.C. 20460
3. Recipient a Accession No.
5. Report Data
09/29/89
6.
8. Performing Organization Rept No.
10. Project/Task/Work Unit No.
11. Contract(C) or Grant(G) No.
(C)
(G)
13. Type of Report & Period Covered
800/000
14.
15. Supplementary Note*
16. Abstract (Umit: 200 word*)
The Wausau Water Supply site, also known as the Wausau Ground Water Contamination
site, is in Wausau, Marathon County, Wisconsin. The site includes six city ground
water production wells along the east and west sides of the Wisconsin River. These
wells supply drinking water to 33,000 people, and is used for industry in the area.
Three'.primary source areas of ground water contamination have been identified; a
municipal' landfill, the Wausau Chemical Company, and the Wausau Energy Company. The
landfill, which is on the west side of the site, operated from 1948 to 1955 and
accepted almost all commercial, industrial, and residential waste generated within
Wausau.. .The landfill appears to be the predominant source of TCE contamination in the
underlying aquifer. On the east side of the river the Wausau Chemical and Wausau
Energy companies are suspected sources of soil and ground water contamination due to .
spills from past operations. Wausau Chemical, a bulk solvent distributer, was
responsible for spilling 1,000 gallons of PCE-contaminated waste in 1983 alone. Wausau
Energy, a petroleum bulk storage and disposal center, has reportedly contaminated soil
and ground water with petroleum by-products. To provide sufficient water of acceptable
quality EPA temporarily installed a granular activated carbon treatment system on one
well in 1984 and VOC stripping towers at the municipal water treatment plant to treat
water from two contaminated wells. The city has been blending treated water with
uncontaminated water to reduce VOC levels. As an interim remedy. (See Attached Sheet)
17. Document Analyaia a. Descriptor*
Record of Decision - Wausau Water Supply,
Second Remedial Action - Final
Contaminated Media: soil, gw
Key Contaminants: VOCs (TCE, PCE)
b. tdentifiers/Open-Ended Terms
WI
c. COSATI Bold/Group
18. Availability Statement
19. Security Claaa (This Report)
None
20. Security Class (This Page)
None
21. No. of Pages
90
22. Price
(See ANS4-Z39.18)
SM Instruction* on Reverse
OPTIONAL FORff 272 (4-77)
(Formerly NTIS-3S)
Department of Commerce
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EPA/ROD/R05-89/109
Wausau Water Supply, WI
Second Remedial Action - Final
76. Abstract (continued) ••....-.
EPA signed a 1989 Record of Decision (ROD) implementing ground water contamination
controls, which included pumping and treatment at one of the landfill.source areas
followed by discharge into the Wisconsin River, to prevent the contaminant plume from
migrating to the source of the river. The primary contaminants of concern affecting the
soil and ground water are VOCs including PCE and TCE.
The selected remedial action for this site includes treating contaminated soil using an
in situ soil vapor extraction (SVE) system and treating gases emitted from the SVE systen
using vapor phase carbon filters; and continued pumping and treatment of ground water
using existing air strippers with modified pumpage rates. The estimated present worth
cost for this remedial., action is $738,000, which includes present worth O&M costs of
$482,000.
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RECORD OF DECISION
SELECTED REMEDIAL ALTERNATIVE
Site Name and Location
Wausau Groundwater Contamination Site
Wausau, Wisconsin
Statement of Basis and Purpose
This decision document presents the selected remedial action for
the Wausau Groundvater Contamination Site in Wausau, Wisconsin,
developed in accordance with CERCLA, as amended by SARA, and to
the extent practicable, the National Contingency Plan. This
decision is based on the administrative record for this site.
The attached index identifies the items that comprise the
administrative record upon which the selection of the remedial
action is based.
The State of Wisconsin has concurred with the selected remedy.
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, may present current or
potential threat to human health, welfare, or the environment.
Description of the Selected Remedy
The selected alternative for the final remedy will address the
principal threats posed by the site. The remaining concerns
(following implementation of the first operable unit) include
three source areas and the contaminant plume affecting the East
Well Field in the City of Wausau's well f-iald. The specific
components of the selected remedy include:
• Installation of soil vapor extraction (SVE) systems to
remove contaminants from soils at each of the identified
source areas;
• Treatment of off-gases from the SVE system operation using
vapor phase carbon units which will be regenerated off-site;.
and
• Groundwater remediation utilizing the municipal wells and
existing air strippers for expedited removal of contaminant
plumes.
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Declaration
Is required by Section 121(a) of CERCIA as amended by SARA, the
selected remedy is protective of human health and the
environment, attains Federal and State requirements that are
ipplicable or relevant and appropriate for the remedial action,
ind is cost effective. This remedy satisfies the statutory
preference for remedies that employ treatment that reduces
:oxicity, mobility, or volume as a principal element and utilizes
permanent solutions and alternative treatment technologies to the
aaximum extent practicable for this site. Because this remedy
fill not result in hazardous substances remaining on-site above
lealth-based levels, the five-year review will not apply to this
iction.
Valdas/V. Adamku€)
Regional AdminM-Crator
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
WAUSAU GROUNDWATER CONTAMINATION SITE
WAUSAU, WISCONSIN
I. SITE LOCATION AND DESCRIPTION
The City of Wausau is located along the Wisconsin River in
Marathon County, Wisconsin. The Wausau Groundwater Contamination
site encompasses an area in the northern section of the city
which includes the City Well Field and six of its production
wells (See Figures 1 and 2).
The City of Wausau provides drinking water for approximately
33,000 people. The City presently operates seven groundwater
production wells, six of which are located on the north side of
the City. A seventh well, City Well 8 (CW8), is located adjacent
to the Wausau Municipal Airport, on the south side of the City.
The water from CW8 has a high concentration of iron and is used
only during peak demand periods. Production wells CW6, CW7, CW9
and CW10 are located west of the Wisconsin River and are
collectively referred to as the West Well Field. The West Well
Field (Figure 2) is located in a predominantly residential area,
although a few industrial facilities are located in this area.
Production wells CW3 and CW4 are located on the east side of the
Wisconsin River and are referred to as the East Well Field. The
East Well Field is located in a predominantly industrial section
of the City. .
The seven production wells are screened in an aquifer of glacial
outwash and alluvial sand and gravel deposits which underlie and
are adjacent to the Wisconsin River. This unconfined aquifer
supplies nearly all potable, irrigation, and industrial water to
residents and industries located in Wausau and the surrounding
areas. Within the study area the alluvial aquifer ranges from 0
to 160 feet thick, .and has an irregular base and lateral
boundaries. .
II. SITE HISTORY AND ENFORCEMENT: ACTIVITIES
A. Site History ;
The City discovered in early 1982 that its production wells CW3,
CW4, .and CW6 were contaminated by volatile organic compounds
(VOCs). The major contaminants include Tetrachloroethene (PCE),
Trichloroethene (TCE), and 1,2-dichloroethene (DCE). Toluene,
ethylbenzene, and xylene were also detected at CW4. TCE is the
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_J ..—'-«i •^==^_I ,
*"*\ ..K II. Ill .-^ *-Ji^
FIGURE 1 REGIONAL LOCATION MAP
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CW6
WEST
STUDY
ARE
CITY SUPPLY WELL
NOTE:
BASE MAP DEVELOPED FROM U.S.G.S. 15 MIN.
QUADRANGLE MAPS HAUSAU EAST & WAUSAU
WEST DATED 1963, PHOTOREYISED 1978.
north
SCALE: 1" « 1000'
FIGURE 2
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predominant volatile organic compound detected at CW6, although
below method detection limit (BMDL) concentrations for PCE and
(DCE) have also been previously reported (Weston, 1984). Since
the contamination was first detected in early 1982, TCE
concentrations from CW6 have ranged from 70 micrograms per liter
(ug/L) to 260 ug/L. The most recent sampling (August 1988)
indicates TCE concentrations of approximately 160 ug/L. Sample
results from the East Well Field (CW3 and CW4) have indicated
considerable PCE, TCE, and DCE impacts at both wells. CW4 has
generally indicated steadily decreasing concentrations of the
three constituents since February 1984. CW3 has indicated
decreasing PCE and DCE concentrations since the VOCs were
discovered in early 1982. However, TCE concentrations at CW3
have remained relatively constant at concentrations ranging
between 80 ug/L and 210 ug/L.
To reduce VOC concentrations, the City originally instituted a
program where uncontaminated water from CW9 and CW7 was blended
with water from CW3, CW4, and CW6 to dilute the VOC
concentrations. However, increasing VOC concentrations in
groundwater caused this method to be ineffective, and resulted in
then current regulatory limits being exceeded.
In 1983, the United States Environmental Protection Agency (U.S.
EPA) awarded the City of Wausau a federal grant to help fund the
design and installation of a packed tower VOC stripper in order
to provide sufficient water of acceptable quality to City
residents. However, because VOC levels in the distribution
system continued to increase, U.S. EPA's emergency response team
was asked for assistance. As an interim measure in June 1984,
the U.S. EPA installed a granular activated carbon (GAC)
treatment system on CW6. VOC stripping towers were installed in
the Summer and Fall of 1984 at the City water treatment plant to
treat water from CW3 and CW4. Subsequently, the GAC system was
removed from service in October 1984. In December 1985 the
Wausau Groundwater Contamination site was added to the National
Priorities List (NPL) for remedial activities under Superfund.
The City :has been blending water treated for VOC removal with
water from.uncontaminated supply sources (CW7, CW9 and CW10) to
reduce VOC concentrations in the water supply distribution
system. Data indicate that prior to installation of treatment
units (pre-July 1984), drinking water samples taken from various
taps in the City of Wausau consistently contained TCE with
concentrations ranging from detectable levels ( >1 ug/L) to 80
ug/L. Lower levels of PCE and DCE were identified shortly after
discovery of the contamination, probably before blending had
reduced the levels of VOCs. Following installation of the packed
tower VOC strippers, the water supply distribution system has had
relatively low levels of VOC's (generally below detection limits
of 0.5 to 1.0 ug/L). These levels are dependent on continued
effective operation of the treatment system for CW3 and CW4, the
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influent VOC concentration for each well, and continued use of
the three uncontaminated wells (CW7, CW9 and CW10).
B. Previous Studies
Previous investigations have identified several potential point
sources of VOC contamination in the vicinity of City production
wells. Becher-Hoppe Engineers, Inc. was contracted by the City
of Wausau to conduct an investigation of the East Well Field in
the vicinity of CW3. The study concentrated on the Wergin
Construction Co. property, the former site of a City maintenance
garage. Foth & Van Dyke and Associates, Inc. performed a
groundwater investigation at the Wausau Energy Company property
located just south of the above property, in order to determine
the effect of past bulk oil operations at the site. STS
Consultants Ltd. performed groundwater investigations at the
Wausau Chemical Company, also located in the East Well Field, and
instituted a groundwater extraction and treatment system to
remediate effects of past VOC releases from their facility
operations. In addition, approximately 1000 cubic yards of
contaminated soils were excavated from the site. Twin City
Testing and Engineering Laboratory, Inc. conducted investigations
in the East Well Field vicinity on behalf of the Wisconsin
Department of Natural Resources (WDNR). Roy F. Weston Inc.
conducted an investigation of both the East and West Well Fields
as part of the U.S. EPA emergency response action. CI^M Hill
Inc. was contracted by the WDNR to perform a hydrogeologic
investigation of the•abandoned City of Wausau landfill, located
on property presently owned by Marathon Electric Company in the
southern part of the West Well Field. RMT Inc. and Geraghty &
Miller Inc., representing Marathon Electric Corporation and the
City of Wausau, respectively, performed a hydrogeologic
investigation to determine the source of TCE in the groundwater
in the vicinity of CW6. Geraghty & Miller, Inc. also installed
several wells in the East Well Field in order to investigate voc
contamination of CW3. Locations of facilities discussed above
are illustrated in "Figure 3, and a listing of previous studies is
presented in Table 1.
Investigations conducted previously have produced inconclusive
results. Potential sources have been identified, but data gaps
existed on source concentration, release rates, migration routes,
aquifer characteristics, effect of river stage and groundwater
pumping on flow direction, and velocity of groundwater and
contaminants. The conclusions of most of these studies include a
recommendation for further study. At least two studies also
expressed the need for a comprehensive investigation to address
the entire well field. The Remedial Investigation/Feasibility
Study (RI/FS), was initiated by U.S. EPA to fill the data gaps
and determine a cost-effective solution to the groundwater
problem.
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MARATHON ELECTRIC FOUNDRY
•r>r R
CORNERSTONE FURNITURE
AV(
4
MAR/T>«QJ4 ELECTRIC
MARATHON ELECTRIC
MANUFACTURIMQ
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wAUSAU CHEMICAL
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J10JND
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'
SIGN COMPANY
FORMER
CITY
LANDFILL -
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LOCATIONS
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-STEEL FLIHT SCAFFOLDING
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FIGURE 3
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TABLE 1
EXISTING REPORTS ON WAUSAU GROUNDWATER CONTAMINATION SITE
1. Groudwater Investigation, (for City of Wausau), Becher
Hoppe Engineers, Inc., 1983.
2. Subsurface Exploration and Testing Program to Evaluate
Ground Water Quality at the Wausau Chemical Facilities
in Wausau, Wisconsin, (for Wausau Chemical Company),
STS Consultants, Ltd., July, 1984.
3. Hydrogeological Investigation of Volatile Organic
Contamination in Wausau, Wisconsin Municipal Wells,
(for U.S. EPA), Roy F. Weston, Inc., September, 1985.
4. Investigation of an Abandoned City of Wausau Landfill,
(for WDNR), CH2M Hill, February, 1986.
5. Existing Conditions Report and Exploration Program, East
Municipal Well Field, Wausau, Wisconsin, (for WDNR),
Twin City Testing Corporation, August, 1986.
6. VOC Groundwater Investigation at the Former Wausau
Energy Facility in Wausau, Wisconsin, (for Wausau Energy
Corporation), Foth & Van Dyke and Associates, Inc.,
July, 1986.
7. Hydrogeological Investigation of the Alluvial Aquifer
Beneath City Well Six, Wausau, Wisconsin, (for City of
Wausau and Marathon Electric), RMT, Inc., and Geraghty
& Miller, Inc., July, 1987.
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C. Previous Operable Unit
An operable unit ROD to address the vest side contaminant plume,
composed mainly of TCE, was signed in December 1988. Prior to
the summer of 1988, CW6, which the City pumped directly into Bos
Creek as waste (subsequently contaminating Bos Creek), served as
a blocking well to the rest of the West Well Field. The
discharge of CW6 to Bos Creek has resulted in a contaminated
groundwater mound between the source area and CW6. The influence
of the groundwater mound may not have fully penetrated the
glacial outwash aquifer, but Phase I RI data suggest that the
mound served effectively to divide the West Well Field
contaminant plume into northern and southern portions, slowing
contaminant migration from the source area.
In summer 1988 the City of Wausau placed CW6 back in service
after completion of a transport pipe to carry contaminated water
to the air stripper located on the east side of the River.
Because of this, the pumping rate of CW6 has increased
substantially, and the untreated discharge to Bos Creek has been
discontinued. These two factors tend to increase the rate of
migration from the source area toward CW6. Water from CW6 is now
treated for VOC removal using the existing air strippers at the
water utility. However, CW6 continues to serve as an interceptor
well, providing the sole protection for the remaining wells in
the West Well Field.
The scope of the operable unit was limited to the contaminant
plume impacting the West Well Field and CW6, since additional
protection of the West Well Field was possible by preventing or
limiting the extent of future contaminant movement to the north.
Previously, protection was provided due to the apparently slowed
contaminant migration to the north caused by discharge of CW6 to
Bos Creek. Implementation of plume migration controls is
expected to effectively limit the time during which CW6 draws in
contaminants, thereby also limiting the period during which water
consumers are exposed to trace levels of contaminants.
The Phased Feasibility Study (PFS) for the interim remedy
included four alternatives to address the contaminant plume
affecting the West Well Field. The selected remedy calls for the
installation of an extraction well located in the southern
portion of the plume, implementation of a treatment system for
removal of contaminants from extracted water, and discharge of
the treated water to the Wisconsin River. The selected remedy
also includes a provision for an additional extraction well if
necessary to effectively address the contaminant plume.
The remedial design for the operable unit is currently under way.
It is expected that the system will be installed by winter of
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5
1989, and operational by spring of 1990.
D. CERCLA Enforcement
CERCLA enforcement activities began at the site in 1986. U.S.
EPA identified five Potentially Responsible Parties (PRPs) as
having potential responsibility as waste generators and/or
transporters. Notice letters informing PRPs of their potential
liabilities and offering them the opportunity to perform the
RI/FS were sent via certified mail on January 17, 1986 to the
five identified PRPs listed below:
* City of Wausau * Wausau Energy Company
* Marathon Electric Company * Amoco Oil Corporation
* Wausau Chemical Company
Several negotiation meetings were held to discuss technical and.
legal issues of a consent decree for the site. However,
negotiations were unsuccessful, and the PRPs declined to
participate in the RI/FS. The U.S. EPA then contracted with
Warzyn Engineering, Inc. in July 1987 to conduct the RI/FS.
Although the PRPs failed to reach an agreement with U.S. EPA,
they have maintained considerable involvement in U.S. EPA's
study. Two of the five PRPs conducted an investigation of the
West Well Field and all have requested split samples and/or
results of data collected. In addition, two of the PRPs, the
City of Wausau and Marathon Electric, have entered into a consent
decree to perform the operable unit Remedial Design/Remedial
Action (RD/RA).
In November, 1987, (as amended April 1988) U.S. EPA filed suit
for recovery of past costs spent on U.S. EPA's emergency response
actions. A settlement was reached between three of the four
defendant PRPs (Marathon Electric, The City of Wausau, and Wausau
Chemical) for approximately 85% of past costs. A consent decree
was entered in federal district court July 18, 1989. A second
consent decree with Wausau Energy is expected to be lodged with
the court in the near future.
Negotiations with the PRPs for the final RD/RA have been
postponed at the request of the PRP group. This is based on the
fact that two of the PRPs are currently involved in the •
implementation of the operable unit RD/RA based on an agreement
with U.S. EPA to perform the operable unit, and to allow the
final remedy PRP group to organize. Special Notice letters will
be sent following ROD signature to the five PRPs listed above.
Negotiations will proceed according to U.S. EPA's general
guidance and policies.
-------
III. COMMUNITY RELATIONS
An RI/FS "kick-off public meeting was held in September 1987, to
inform the local residents of the Superfund process and the work
to be conducted. Issues raised during the meeting, attended
mostly by PRP agents and City officials, included the cost of the
RI/FS, the estimated time to complete the study, and the number
of previous studies performed for the site.
A second public meeting was held in October 1988 to discuss the
findings of the Phase I RI and PFS, and to present the proposed
plan for an operable unit at the site. Two formal public
comments were received during the public meeting and written
comments were also received during the public comment period.
All comments received during the comment period and U.S. EPA's
responses were included in the responsiveness summary for the
Interim ROD.
Information repositories have been established at Wausau City
Hall, 407 Grant Street, and the Marathon County Public Library,
400 First Street, Wausau, Wisconsin. In accordance with section
113(k)(l) of CERCLA, the administrative record for che site is
available to the public at these locations. The draft FS and the
proposed plan were available for public review and comment from
August 14, 1989 to September 12, 1989.
A public meeting to discuss the findings of the RI/FS and to
present U.S. EPA's preferred alternative for the final remedy was
held August 22, 1989 in the Wausau City Hall. Four formal public
comments were received during the public meeting. All of the
comments were in support of U.S. EPA's preferred alternative.
One additional comment was received during the remainder of the
public comment period. All comments will be addressed in the
responsiveness summary of this document. The provisions of
sections 113(k)(2)(i-v) and 117 of CERCLA relating to community
relations have been satisfied.
IV. SCOPE AND ROLE OF RESPONSE ACTION
The scope of this response action is to address the remaining
concerns (principal threats) at the site. As discussed, a
previous operable unit action at the site addresses the
contaminant plume originating from the former landfill/Marathon
Electric source area which affects CW6.
During development of the final FS, it was determined that the
deep plume which originates from the former City landfill area
and migrates under the River to CW3 would best be addressed by
purging groundwater at the same location as the interim remedy
extraction system. Therefore, it was determined that an increase
in the minimum pumping rates called for in the extraction system
-------
and modifications to the monitoring plan would provide the most
effective remediation for this contaminant plume. It was also
assumed that the City would continue to use CW3 as a supply well
and thus continue to remove contaminants from the most eastern
portion of the plume.
The selected alternative for the final phase of the Wausau
project, in conjunction with the operable unit, will address all
concerns at the site. Remaining concerns include three source
areas and the shallow east side groundwater contaminant plume
originating from the Wausau Chemical source area. The identified
source areas include; former City landfill/Marathon Electric
property, Wausau Chemical property, and Wausau Energy property.
The final remedy for the site is intended to address the entire
site with regards to the principal threats to human health and
the environment posed by the site as indicated in the risk
assessment for the site. The findings of the risk assessment are
included in the RI Report and are summarized in a later section
of this document.
V. CURRENT SITE STATUS AND SITE CHARACTERISTICS
A. Current Site Status
The RI/FS was completed in August 1989 for U.S. EPA by its
contractor, Warzyn Engineering, Inc. The RI entailed two phases
of field sampling events. Phase I of the RI field work was
conducted from August through January 1987, results of which are
summarized in the April 1988 technical memorandum. Phase II of
the RI field work was conducted from June to September 1988.
Results of both phases of work are included in the RI report for
the site.
The FS details the development and evaluation of an array of
remedial action alternatives to address the entire Wausau
Groundwater Contamination site and sources impacting it.
B. Site Characteristics
1. Hydrogeology
The City production wells are located within glacial outwash and
alluvial sediments underlying and adjacent to the Wisconsin
River. The aquifer is located within a bedrock valley which is
underlain and laterally bounded by relatively impermeable igneous
bedrock. Groundwater flow within the unconfined glacial aquifer
has been drastically changed by the installation of the
production wells. Under non-pumping conditions, groundwater
flows toward the Wisconsin River and its tributary (Bos Creek).
Groundwater naturally discharges at the surface water bodies.
-------
8
However, under pumpage conditions, groundwater flows toward the
production wells. The natural groundwater flow directions are
frequently reversed due to City well pumping which induces
recharge of surface water into the aquifer. The horizontal flow
in the vicinity of the well field is indicated by the
potentiometric contours shown in Figure 4.
The potentiometric surface map also indicates that the cone of
depression from the East Well Field appears to affect groundwater
flow below and to the west of the Wisconsin River. Monitoring
well nests located at Marathon Electric indicate very slight
downward gradients adjacent to the Wisconsin River. Below the
Wisconsin River, the East Well Field production well pumpage has
induced surface water recharge of the aquifer, causing flow
downward through the river bed and toward CW3.
Aquifer hydraulic conductivity tests performed during the Phase I
RI investigation indicated hydraulic conductivity values ranging
from 1.7 x 10~4 cm/sec to 8.1 x 10"2 cm/sec. The overall average
hydraulic conductivity of the outwash aquifer is approximately
2.2 x 10~2 cm/sec, based on test data at monitoring wells.
2. Chemical Characteristics
a. Groundwater Quality
Groundwater quality sampling conducted during both phases of the
field investigation has identified a vertical and lateral
distribution of total chlorinated ethenes which suggests that a
minimum of three sources are affecting the City well field. The
estimated areal distribution of total chlorinated ethenes is
shown in Figure 5. The distribution is based on a combination of
data obtained from laboratory VOC analyses of Rounds 1, 2, and 3
groundwater samples (October 1987 to September 1988), and field
laboratory analyses of groundwater samples collected during
drilling (October and November 1987).
West side monitoring wells delineate a deep (greater than 100
foot) north-south trending TCE plume. Based on the vertical
distribution of TCE throughout the aquifer in the vicinity of the
old City landfill and the presence of TCE in the unsaturated zone
in this area, a source appears to be located within the northern
portion of the former City landfill/Marathon Electric property.
The plume appears to have migrated northward, under influence of
pumpage from CW6. The highest TCE concentration (4200 ug/L) in
the plume was detected approximately 550 feet south of CW6.
TCE was also observed in the shallow aquifer between Bos Creek
and CW6. This plume is shown on Figure 5 by the lightly shaded
contours between Bos Creek and CW6. The shallow aquifer TCE
contamination appears to result from the induced infiltration of
-------
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-------
surface water from Bos Creek, which has been contaminated by the
discharge from CW6. The induced surface water recharge of the
aquifer is evident from the downward vertical gradients at
monitoring well nests in that area. Based on laboratory analyses
of samples collected during the RI field work, TCE
concentrations adjacent to the CW6 discharge were above 100 ug/L.
TCE concentrations in the ponded area downstream were
approximately 70 ug/L. TCE was not detected in surface water
samples collected upstream of the CW6 discharge, nor was it
detected at the point of discharge of Bos Creek to the Wisconsin
River.
The distribution of TCE in monitoring wells located between the
Wisconsin River and CW3 suggest eastward migration of a deep TCE
plume below the Wisconsin River also from the vicinity of the
former City Landfill (refer to Figure 5). TCE appears to be
vertically distributed throughout the aquifer in the vicinity of
the old City la. -ifill. Slight vertical downward gradients were
observed in monitoring wells in the area. The highest
concentrations of TCE were detected at a depth of approximately
115 feet. After moving into the deeper portion of the aquifer, a
portion of the plume appears to migrate eastward under the
influence of pumpage from CW3 (refer to Figure 4).
East side monitoring wells indicate three plumes within the East
Well Field area, one from the west side originating from the
former City landfill/Marathon Electric property (discussed above)
and two originating southwest of CW3. These two plumes are
restricted to the shallow portion of the aquifer (upper 40 feet),
and consist of primarily PCE, TCE, and DCE. Both of these plumes
have resulted from releases of PCE from the Wausau Chemical
facility.
A large widely dispersed VOC plume extending eastward from the
Wausau Chemical property was identified during the three sampling
rounds. The highest concentrations of VOCs in this plume were
detected in the vicinity of the Wausau Chemical storage area
behind the southern- part of the building.
A second plume was detected north of the Wausau Chemical facility
in the vicinity of the northern loading dock. This plume was
differentiated from the other plume by the relative absence of
PCE degradation products (TCE, 1,2-DCE, etc.). Analyses
conducted for Round 3 samples (May 1988) indicate a PCE
concentration of approximately 2000 ug/1. Based on the
differences in plume composition and areal distribution, the two
shallow aquifer impacts appear to be the result of separate
release events from one or more sources at the Wausau Chemical
facility.
Comparison of VOC concentrations and pumpage rates at CW3 and CW4
suggests that both wells have experienced multiple impacts from
-------
10
the same source area; the extent of impact being dependant on
pumping schemes of the City's supply wells, river stage, and the
strength of the source. Total VOCs at both CW3 and CW4 have been
decreasing over time indicating a possible reduction in source
intensity. However, TCE concentrations at CW3 have remained
relatively consistent which is attributed to the TCE plume
migrating under the River from the west side.
b. Sources of Contamination
Contamination source areas were identified and characterized
based on results of field sampling of soils, landfill contents
(using test pits and soil borings), groundwater, surface water,
sediment and soil gas media. Based on sampling activities
conducted during the RI, four source areas of VOCs were
identified. Two of these sources are located oh the west side of
the Wisconsin River (the former City landfill and Bos Creek) and
two sources are located on the east side (Wausau Chemical and
Wausau Energy). . ' :
The former City landfill/Marathon Electric property occupies a
former sand and gravel pit located on the west bank of the
Wisconsin River. The landfill, Which consists of approximately
4.5 acres, operated between 1948 and 1955 and\accepted almost all
commercial, industrial, and residential waste generated within
the City of Wausau. The majority of the landfill is currently
covered by a bituminous pavement parking lot, however the
southern portion is vegetated.
The predominant source of TCE contamination to CW6 and CW3
appears to be the former City landfill/Marathon Electric
property. Elevated concentrations of TCE were detected in
groundwater, soil, and soil gas samples obtained from the
northern portion of the landfill. Soil gas concentrations within
the landfill range from below minimum detection limits (1.0 ug/L)
to approximately 107 ug/L. Soil samples obtained from borings in
the vicinity of the landfill contain concentrations of
approximately 200 ug/kg* Groundwater samples obtained from the
water table in the vicinity of the landfill indicate TCE
concentrations ranging from 16 ug/L to approximately 1900 ug/L.
Also detected in the vicinity of the landfill were 1,1,1-
trichloroethane (TCA), 1,2-dichloroethene, chloroform, and carbon
tetrachloride at concentrations generally below 100 ug/L.
In addition to VOCs, contaminants identified in landfill
soil/waste samples include polycyclic aromatic hydrocarbons
(PAHs) and metals. PAHs were found throughout the fill, with the
highest concentrations observed in the center of the fill area.
Heavy metals were distributed throughout the fill. Chromium,
zinc, and nickel were also detected in groundwater samples from
•beneath the fill. These metals appear to be restricted to the
immediate vicinity of the landfill and have not been detected in
-------
11
groundwater samples outside of the fill area.
Based on calculations performed for the. RI, the total amount of
VOCs remaining in the unsaturated soils in the northern portion
of the landfill is estimated to be approximately 300 pounds.
This is considered an estimate and could vary considerably if
contamination exists beneath the fill and/or if areas of
undetected high concentrations or non-aqueous phase of
contaminants exist. : ,
As discussed previously, low levels of TCE were also detected in
samples from shallow monitoring wells on the west side in the
vicinity of Bos Creek (see Figure 5),. \ The shallow contamination
appears to be a result of infiltration, of TCE contaminated water
to the aquifer from CW6 discharging; to the Creek.
The Wausau Chemical Company is located between CW3 and CW4 on the
east bank of the Wisconsin River. The facility, established in
1964, is a bulk solvent distributor and ai transfer station for
shipment of waste chemicals and solvents from area businesses.
The facility experienced two documented PCE spills in 1983
totaling more than 1000 gallons, and has been cited for general
poor 'housekeeping' practices. As early as 1975, workers at the
adjacent water filtration plant reported "noxious odors" in
excavated soils during expansion of the plant.
Solvents released from the Wausau Chemical source areas are
responsible for a large percentage of the shallow groundwater
contamination in the East Well Field. Soil gas and soil boring
data reflecting the distribution of VOCs in unsaturated soils
were collected as part of the soil gas survey and during soil
boring for source characterization. Results of this data
indicate higher concentrations of contaminants are located in the
southern portion of the site with decreasing concentrations
within an elongated contaminant zone trending toward the east-
northeast. However/elevated concentrations of PCE were also
found in unsaturated soils near the north loading dock. The
highest levels of PCE in soil gas was reported from the southern
end of the facility at a concentration of 4080 ug/1. Analyses of
soil samples indicate 3500 ug/kg of PCE in the vicinity of the
north loading dock, and 1000 ug/kg at the south end of the
property.
Based on calculations performed for the RI, the total amount of
VOCs remaining in the soils at Wausau Chemical is approximately
300 pounds. This is considered an estimate and could vary
considerably if contamination exists beneath either the
filtration plant or the Wausau Chemical building.
The Wausau Energy property located directly south of CW3 was also
identified as a source for groundwater contamination. The
facility operated as a petroleum bulk storage and distribution
-------
12
center from the late 1940's until 1983. Previous property owners
include Amoco Oil and Rush Distributing. Historical data
indicate that at least seven above ground storage tanks were
located on the southern half of the property and contained
various petroleum products.
Soil gas and unsaturated soil samples have been conducted at the
property. Results indicate various petroleum by-products,
commonly referred to as BETX (benzene, ethylbenzene, toluene, and
xylenes) in unsaturated soils and groundwater beneath the site.
PCE was detected at low levels in isolated soil samples and soil
gas samples at depth. The maximum BETX concentration reported in
on site soils was 25,100 ug/kg. The maximum concentration of PCE
found in soils was 8,600 ug/kg (from a previous study-Foth & Van
Dyke) and 17.4 ug/kg found in soil gas samples from the property.
VI. SUMMARY OF SITE RISKS
CE3CLA requires that U.S. EPA protect human health and the
environment from current and potential exposure to hazardous
substances found at the site. An Endangerment Assessment was
conducted as part of the RI in order to assess the current and
potential risks from the site. This section summarizes the
Agency's findings concerning the risks from exposure to
groundwater and air emissions at this site.
Assessment of site related risks involved the identification of
contaminants of most concern, routes of contaminant migration and
populations potentially exposed to the contaminants. This
information was then used to estimate exposure from contaminants
for the population, which was then compared to chemical toxicity
to arrive at an estimate of health risks for the site.
A. Identification of Contaminants of Concern
More than 50 compounds were identified from the RI data as being
present at the site (Table 2). A subset of the total number
identified was selected based on which compounds pose the
greatest health risks, the concentrations and frequency of
detection, and the physical properties relating to mobility and
persistence.
Based on the above criteria, the following indicator chemicals
were considered to be representative of site contamination and to
pose the greatest potential health risk.
-Tetrachloroethene (PCE)
-Trichloroethene (TCE)
-1,2-Dichloroethene (DCE)
-------
TABLE 2
Medium
GROUNDWATER
All Locations
Production Wells
CW3, CW4, CW6
TARGET COMPOUND LIST CHEMICALS DETECTED
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE '
WAUSAU, WISCONSIN
Chemical Concentration
Chemical Minimum
Volatile uq/L
Chloromethane 4
Vinyl chloride 3
Metnylene chloride 1
Acetone 2
1,1-Oichloroethene
1,1-Oichloroethane
1,2-Dichloroethene (total) 1
Chloroform 2
2-Butanone '--
1,1,1-Trichloroethane 1
Carbon tetrachloride 2
Trichlorethene 1
1,1,2-Trichloroethane 2
Benzene 18
4-Methy1-2-pentanone
Tetracnloroethene 1
Toluene 2
Chlorobenzene 2
Ethyl benzene 3
Xylenes (total) 16
Semivolatile uo/L
Phenol
Naphthalene
2-Methylnaphthalene
Fluor'ene
Pentachlorophenol
Phenanthrene
8is(2-ethylhexyl)phthalate 3
Pesticide/PCB
None Detected
Metal/CNb
Barium
Chromium
Iron
Manganese
Zinc
Volatile
Acetone
1,2-Dichloroethene (total)
Trichloroethene
Tetrachloroethene
Chlorobenzene
Semivolatile
Hone Detected
Pest1cide/PCB
None Detected
uq/L
206
28
169
69
2750
uq/L
1
53
7
Maximum
uq/L
7
6
190
3070
2
3
1300
44
5
53
69
4200
4
310
2
2440
890
54
440
2000
uq/L
2
22
23
4
6
4
19
uq/L uo/L
325
594
18100
6100
2860
16.
20
150
14
15
Geometric
Mean
uo/L
5
4
8
11
20
11
3
19
29
2
125
45
46
7
53
428
uq/L
259
77
1800
937
2800
uq/L
9
100
13
Number Locafic~s
Sampled for A-a'/s•s
Total
134
Positive
fj A • a /- • ' ^r
16
31
31
32
-------
Medium
SURFACE SOILS
Table 2
(Continued)
': , Chemica]. /.
'. ' . ': Metal /CN'
.:'.-•' -Iron .•;
"Manganese
-S '-, Volatile.
Methylene chloride
1, 1, IrTrichloroethane
TetrachToroethene
Xyl.enes (total)
Semi volatile
Phenol
4-Me thy 1 phenol
'Benzoic' acid
Naphthalene
2-Methyl naphthalene
Aceriapnthy lene
Acenaphthene
Dibenzofuran
Fluorene
Phenanthrene
Anthracene
Flouranthene
Pyrene -.•••'.
Butyl'benzylph thai ate
Benzo(a):antnracene
Bis (2-ethylhexyl)phtha late
Chrysene
Oi-n-octylphthalate
Benzb(b]fluoranthene
Benzoikjfluoranthene
Benzo(a)pyrene
Indenof 1 , 2 , 3-cd) pyrene
Dibenz (a, h) anthracene
8enzo(g,h, i)perylene
Pesticide/PCB
Not Analyzed
MetaT/CN
Hot Analyzed
Chemical
Minimum
uo/L
957
1610
uo/Vq
6&
..
..
--
uo/kg
89
37
,32
2
51
38
100
2CO
32
200
150
59
110
150
390
250
..
100
210
230
Concentration
Maximum
ua/L
5300
2920
uqAq
190
3
3
4
uq/kq
93
200
160
720
770
110
69
180
120
2500
480
6600
2900
390
2400
1600
3200
380
5400
1600
2700
1200
390
1400
Geometric
Mean
uq/L
2110
2110
uq/Vq
110
..
..
--
uq/kg .
90
192
264
22
59
82
109
651
155
1300
910
150
749
489
861
1380
..
604
614
655
SURFACE WATER
8os Creek
Volatile uq/L
1,2 Oichloroethene (total) 1
Trichloroethene 1
Tetrachloroethene 1
1
41
2
Number Locations
Sampled -fsr £na'vs•' s
. ' Pbs-tive
•Detection
12
10
2
Semlvolatile
Not analyzed
Pesticide/PCB
Not Analyzed
Metal/CN
Not Analyzed
-------
Table 2
(Continued)
Chemical Concentration
.Medium-
•'••'• Chemical Minimum
Wisconsin 'River Volatile uq/L
SEDIMENT
Bos Creek
SUBSURFACE
1,2-Oichloroethene (total)
Chloroform 1
Tetrachloroethene
. . , '• Semivdlatile
'• : Not Analyzed
; Pesticide/PC3
: Not Analyzed
•:•' ' Metal /CN
•:- No.t Analyzed
• '•.. ; Volatile ug/kq
Acetone ...... jg
: ','.:. ;'.!'. 2-Oichloroethene (total) 6
; Trichloroethene 6
Toluene
Semi volatile uq/kq
None Detected
.'• Pesticide/PCB
None Detected
'•Metals
Not Analyzed
SOILS
• Volat i IP nn/tn
* w i a w i i c UU/KU
Methylene chloride 1
Tricnloroethene . 4
Tetrachloroethene 1
To 1 u P n ^ 1
1 W 1 Ud 1^ I
"Ethylbenzene 4
Xylenes (total) 2
Semi volatile uq/kq
Phenol •-
Naphthalene
2-Methylnaphtalene
Oimethylphthalate 110
Fluorene 63
Phenanthrene 63
Anthracene 48
Di-n-butylphthalate 58
Flouranthene 30
Pyrene 31
Benzo(a)anthracene 98
Chrysene 130
Bis(2-ethylhexyl)phthalate 45
Geometric
Maximum .Mean
uq/L uq/L
1
4 2
6
uq/kq uq/kq
190 58
200 51
17 59
7
uq/kq uq/kq
uq/kq uq/kq
2000 43
10 6
3500 77
46 5
2900 37
21000 22
uq/kq uq/kq
320
4900
16000
140 120
1600 320
2600 260
120 85
76 66
1400 220
1300 210
660 250
750 290
&4 60
Number Loca-t :"<•-;
Sa.-npied far Jna7-/;'^
Positive
Oetec:::.-
11
29
29
12
9
•5
7
2
2
11
6
2
15
12
6
6
5
-------
Medium
LANDFILL REFUSE
Table 2
(Continued)
Chemical Concentration
Chemical
Benzofb fluoranthene
Benzofk fluoranthene
8enzo(a pyrene
Indeno(l, 2 ,3-cd) pyrene
Dibenz (a, h) anthracene
Benzo(g, h, i)perylene
Pesticide/PCS
Not Analyzed
Metal/CN
Copper
Volatile
Hethylene chloride
Acetone
1,2-Oichloroethene (total)
Trichloroethene
Toluene
Ethyl benzene
Xylenes (total)
Semivolatile
Phenol
2-Chlorophenol
1,2-Dichlorobenzene
2-Methyl phenol
4-Methy] phenol
Isophorone
1.2,4-Trichlorobenzene
Naphthalene
4-Chloro-3 -methyl phenol
2 -Methyl naphthalene
2-Chloronabhthalene
Acenaphthy lene
Acenaphthene
Dibenzofuran
Fluorene
Pentachlorophenol -
Phenanthrene
Anthracene
Fluoranthene
fyrene
.Butylbenzylphthalate
Benzo(a) anthracene
Bis(2-ethy1hexyl)phthalate
Chrysene
Benzo(b) fluoranthene
Benzoi k) fluoranthene
Benzo(a) pyrene
Indenofl, 2. 3-cd) pyrene
Dibenz (a ,h) anthracene
Benzo(g.h, i)perylene
Pesticide/PCB
Arochlor 1260 :;
Minimum
110
100
120
130
130
mq/kq
--
uq/kg
•r 9
71
21
36
3
2
4
uq/kg
..
.
-
-
-
*
*
49
65
--
45
19
82
820
170
19
60
63
130
420
110
54
410
430
480
640
280
560
uq/kg
850
Maximum
680
760
750
680
74
800
mq/kq
107
uq/kq
1900
160
220
160000
750
4
24
uq/kq
2200
2200
210
75
830
130
1200
1300
2300
890
170
130
730
330
500
32000
15000
2200
45000
49000
2300
24000
54000
25000
25000
25000
25000
31000
1200
14000
uq/kq
2300
Geomet-ic
Mean
220
210
250
220
270
mq/kq
—
uq/kq
. 70
100
67
680
60
3
13
uq/kq
..
--
--
• --
--
..
150
150
.-
180
63
186
2900
1100
250
1600
1700
500
1400
860
970
1700
1400
1200
940
490
1600
uq/kq
1400
Number Locations
Sampled for i.iaivs-is•
Total
15
15
Positive'
Detection
1C
9
• 3
6
1 .
i
i
-------
Medium
Table2
(Continued)
Chemical Concentration
Chemical
Hetal/CNC
Arsenic
Chromium
Copper
Mercury
Zinc
Minimum
mqAq
107
0.5
323
Geometric
Maximum Mean
mq/ko
76
1130
1410 383
1.9 1.2
3260 2160
Number Locaflcns
Sampled for AnaivS'S
Total
14
Detection
-------
13
These compounds have been used to evaluate toxicity, exposure
pathways, and potential health risks for the site.
B. Exposure Assessment
Groundwater in the area is the current source of drinking water
for the City of Wausau which provides potable water to
approximately 33,000 people. The aquifer of concern is a class I
aquifer (sole-source aquifer without a viable alternate source of
supply) and is highly vulnerable to contamination. The City of
Wausau treats water prior to distribution through the use of two
air strippers. The air strippers effectively reduce VOC
concentrations to below the detectable levels. Historical data
indicate that during the period of 1982 through mid-1984, levels
of VOCs in the City supply ranged from 10 ug/1 to 100 ug/1.
However, it is not known how long, prior to 1982, the City's
water supply contained elevated levels of VOCs. Therefore, the
exposure scenario for drinking water did not address possible
exposures prior to 1982.
Currently there are no known private wells used for drinking
water within the study area. In addition, there is a City of
Wausau ordinance requiring residents to utilize the municipal
supply for domestic purposes. However, in developing
hypothetical exposure scenarios for groundwater, institutional
controls were not considered adequate for protection from
potential future use of private wells.
Stripping tower treatment of contaminated groundwater is
currently occurring at the City water treatment plant and at
Wausau Chemical. In addition, the effluent from the extraction
well proposed for the interim remedy will also involve dispersion
of VOC emissions to the air. Indicator contaminants dispersed
into the air from groundwater treatment pose a potential exposure
pathway to employees of companies and residents near the sources
of air emissions.
The potential exposure pathways for the site are listed below and
summarized in Table 3. Potential health risks were evaluated for
the following exposure pathways and potentially exposed
population.
- Residents using municipal water assuming they are exposed to
contaminant concentrations equal to the laboratory detection
limits of 0.5ug/l for PCE and TCE, and 1.0 ug/1 for DCE.
- Hypothetical users of private well water assuming a private
well is installed within the contaminated aquifer in the
future. It was assumed that a user would be exposed to the
highest concentrations found in groundwater, approximately
4300 ug/1, to obtain the worst case scenario for this
-------
TADIE3
POTENTIAL EXPOSURE PATHWAYS
FEASIBILITY STUDY
WAUSAU UATER SUPPLY NPL SITE
UAUSAU, WISCONSIN
Environmental
HediuH
Groundwater
Exposure
Point
Municipal water
supply
Private well
water
Exposed
Receptors
Uausau residents
Uausau residents
with private wells
Routes
Exposure
Ingestion,
inhalation,
dermal absorption
Ingestion.
inhalation.
dermal absorption
Pathway
Complete?
Yes
No: currently no
private we)Is in
contaminated aquifer.
However potential
for future private
wells exists
Exposure
Potential
Very low; air
stripping has
reduced contaminant
concentrations to
below detection limits
Hone; currently.
Moderate; future
private well users
could be exposed to
untreated water
Risk
Quantified?
Yes
Yes
Surface soils
Surface water
and sediments,
Bos Creek and
Wisconsin River
Subsurface soils
and landfill
refuse
Air
Direct contact Uausau residents
Direct contact Children playing
in creek or river
Aquatic organisms,
terrestrial
wildlife
None; subsurface
location
•ininizes
contact potential
Direct contact
Direct contact,
volatilization
from soils or
landfill refuse
Direct contact.
emissions from
air strippers
Uausau residents
Remediation
workers
Watisau residents,
company employees
Uausau residents,
company employees
Dermal absorption,
incidental
ingestion
Dermal absorption,
incidental
ingestion
Bioconcentration,
bioaccumulation
Dermal absorption,
incidental
ingestion
Dermal absorption,
incidental
ingestion
Inhalation
Inhalation
Not determined
No, contaminated
water no longer
discharged to
Bos Creek
No, contaminated
water no longer
discharged to
Dos Creek
No
Not determined
No significant
volatilization
not occurring
Yes
Very low; not No
considered to be
above background
None NO
None No
None No
Very low, workers No
assumed to be
utilizing
protect ive gear
None NO
Moderate dispersion of Yes
VOC emissions may expose
Uaiisau residents and
employees of companies near
tin: sources
-------
14
exposure pathway.
Residents and company employees exposed via air emissions
in the vicinity of the emission sources. Estimated
contaminant emissions from the source areas were calculated
assuming continuous operation of the air strippers and a
constant rate of loading of VOCs.
The contaminant intake, and thus risk that an individual would
likely incur from exposure to an indicator chemical was estimated
for the exposure pathway of concern by incorporating standard
exposure assumptions of 70-kg man,ingestion of two liters of
water per day, inhalation rate of 1.3 m3/hr and a skin surface
area of 18,200 cm2 for water, and an inhalation rate of 20m3/day
for air emissions.
C. Toxicity Assessment
Based on toxicological studies performed on laboratory animals,
both PCE and TCE are classified as probable human carcinogens.
Scientific data collected to date are not sufficient to classify
DCE as to its carcinogenic potential. Therefore, no cancer
potency factor could be derived for DCE and thus, DCE was not
included in the calculation of site risks. PCE is also assigned
a reference dose value. This value represents the levels to
which humans can be exposed on a daily basis without adverse
effects. The critical toxicity values (i.e., cancer potency
factor and reference dose) for PCE and TCE are listed in Table 4.
The U.S. EPA considers individual excess cancer risks in a range
of 10~4 to 10~7 as protective; however, the 10~6 risk level is
used as a point of departure for setting cleanup levels at
Superfund sites. A 10~6 is considered appropriate as a point of
departure for setting cleanup levels at this site considering
that groundwater is currently used for drinking water and is the
sole-source of drinking water for the residents of Wausau.
D. ?MTONfly"y of Risk Characterization
Under current water use conditions, a potential carcinogenic risk
of approximately one in one million (1 x 10~6) was calculated for
users of municipal water for the combined effects of PCE and TCE.
These risk levels are based on undetectable levels of VOCs
present in the treated water within the City water distribution
system. The short-term carcinogenic risks to health associated
with PCE and TCE contamination would appear to be minimal under
current water usage practices. The long-term cancer risk
associated with City water use was calculated to be 1.5 x 10~6
based on a life time of 70 years (see Table 5).
-------
TABLE 4
CRITICAL TOXiCiT-' VALUES FOR INDICATOR CONTA-. iNANT-s
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
ndicator
'ontaminant
etrachloroethene
(PCE)
richloroethene
(TCE)
,2-Oichloroethene
Total) (OCE.)
Reference Dose (ma/kg/dav)
Oral
Inhalation
Subchronic
Chronic
l.OE-02
Subchronic Chronic
EPA
Weight of
Evidence
Carcinogen;
Potency Factor
(mq/Vc/aav)-1
Class
i f icationb
82
82
0
Oral
5.10E-02
1.10E-02
Ir.na: atic'r.
3.2CE-02
1.2E-02
* Values obtained from Integrated Risk Information System (IRIS) (4/89).
3 Group A (Human Carcinogen) Sufficient evidence from epidemiologic studies to support a causal association
between exposure cancer.
Group 81 (Probable Human Limited evidence of carcinogenicity in humans from epidemioloqical studies
Carcinogen)
Group 82 (Probable Human Sufficient evidence of carcinogenicity in animals, inadequate evidence of
Carcinogen) carcinogenicity in humans.
Group C (Probable Human Limited evidence of carcinogenicity in animals.
Carcinogen)
Group 0 (Not Classified) Inadequate evidence of carcinogenicity in animals.
Group E (NO Evidence of No evidence for carcinogenicity in at least two adequate animal tests or m
Carcinogenicuy both epidemiologic and animal studies.
in Humans)
-------
15
The U.S. EPA has set a Maximum Contaminant Level (MCL) of 5 ug/1
TCE for drinking water. An MCL of 5 ug/1 for PCE is under
consideration for proposal in the near future. MCLs are
enforceable standards promulgated under the Safe Drinking Water
Act. Because PCE and TCE are carcinogenic and are not considered
to be without hazard below a given threshold, the U.S. EPA has
set a non-enforceable Maximum Contaminant Level Goal (MCLG) of
zero for TCE in drinking water and is considering the same MCLG
for PCE. Because it is not possible to accurately measure levels
of these compounds below the minimum detection li:ait, a future
health risk may exist to individuals consuming w._er over a
prolonged period of time during which PCE and TCE are present,
but below detectable limits.
In addition, protection of residents from exposure to the
contaminants of concern is dependent on adequate treatment of the
water. The potential for exposure exists in that failure of the
treatment system could result in an exposure pathway through the
City's drinking water. Based on the possibility of failure of
the air strippers, a potential future risk of exposure to PCE and
TCE via drinking water ingestion exists at the site.
The calculated potential carcinogenic risks for future use of
private well water were approximately 1000 times higher than
those calculated for users of municipal water, assuming users
would be exposed to maximum contaminant concentrations identified
in groundwater at the site (see Table 5). Because institutional
controls were not considered adequate for protection from private
well usage, it was determined that a potential future risk of
exposure via groundwater exists at the site.
The potential cancer risk to individuals inhaling contaminated
air emanating from the stripping towers was estimated based on
modeling of the combined contaminant plumes from the City's air
strippers and the Wausau Chemical air stripper. Model results
for a worst case scenario for exposure of receptors to air borne
contaminants estimated a cancer risk of 1.7 x 10~6. The
estimated current risk level is not considered to present an
appreciable health risk to residents. However, all alternatives
evaluated in the FS include treatment of off-gases to eliminant
any additional VOC emissions. In addition, the selected
alternative calls for elimination of the Wausau Chemical air
stripper, which will reduce the level of contaminants in the
contaminant plume.
VII. DESCRIPTION OF ALTERNATIVES
A. Response Objectives
The feasibility study was initiated to evaluate alternatives for
remediation of the groundwater contamination and source areas at
the site. Based on the risk assessment, three primary site-
-------
TABLE 5
MAXIMUM CONCENTRATIONS AND RESULTING POTENTIAL CANCER RISKS
FOR CONTAMINANTS AND PATHWAYS OF CONCERN
AT THE WAUSAU GROUNDWATER CONTAMINATION SITE
EXPOSURE PATHWAY/ MAXIMUM POTENTIAL
CONTAMINANT OF CONCERN CONCENTRATION CANCER RISK
1) MUNICIPAL WATER SUPPLY*
PCE .5 ug/1 8.9 x 10~7
TCE .5 ug/1 6.3 x 10~7
Exposure Pathway/Risk Total: 1.5 x 10~6
2) GROUNDWATZR (PRIVATE WELLS)b
PCE 2440 ug/1 4.5 XlO"3
TCE 4200 ug/1 5.2 X 10~3
Exposure Pathway/Risk Total: 9.6 x 10~3
3) AIR EMISSIONS FROM STRIPPERS
PCE 1.3 ug/m3 4.8 x 10~7
TCE .37 ug/m3 1.2 x 10"6
Exposure Pathway/Risk Total: 1.7 x 10"6
a: Concentrations of indicator contaminants in the municipal
system were assumed to be equal to laboratory analytical
method detection limits.
b: Concentrations of indicator contaminants used in the private
well scenario were the maximum concentrations detected in
groundwater at the site.
-------
16
specific response objectives were identified; 1) reduction of
long-term exposure to low levels of VOCs from 'ingestion-of
drinking water; 2) protection from potential future use of
private wells in contaminated grouridwater; and, 3) protection
from emissions of contaminants from proposed water treatment
systems that release VOCs to the atmosphere.
B. Development of Alternatives
In developing alternatives for this site several initial
assumptions were made regarding base line conditions at the site.
It was assumed that the west side extraction system would be
installed and operated as described in the Interim ROD. It was
also determined, based on computer modeling of the site, that the
deep TCE plume moving under the Wisconsin River to CW3 would best
be addressed at the same location as the proposed extraction well.
at the former landfill source. Therefore, it was determined that
an increase in the proposed minimum pumping rates called for in
the west side extraction system and modifications to the
monitoring plan would provide the most effective remediation of
this contaminant plume.
As discussed, the remaining areas of concern for the site include;
the source areas and the shallow east side contaminant plume
originating from the Wausau Chemical source area. The three
identified source areas include the former City landfill, the .
Wausau Chemical property, and the Wausau Energy property.
At the Wausau Energy site, petroleum derived compounds have been
found in groundwater samples directly below the site. Although
toluene, ethylene, and Xylene were previously detected in CW4,
no off-site migration of contaminants was been detected during
the RI/FS, although toluene, ethylene and xylene were previously
detected in CW4. Because off-site monitoring does not indicate
groundwater impacts from the Wausau Energy source at present,
groundwater remediation at Wausau Energy is not addressed as
part of the final remedy. However, contaminated soils found at
Wausau Energy will be addressed under the discussion of source
control.
A variety of technologies to address response objectives were
identified for further consideration including several for
remediation of source areas. However, considering the nature of
the source areas, and the contaminants present, only one source
control technology (soil vapor extraction) was retained from the
screening of technologies.
Following screening of technologies, alternatives were developed
and screened for appropriateness based on response objectives.
Five alternatives remained after screening and were subjected to
detailed analysis using the nine evaluation criteria developed
under the National Contingency Plan (NCP). Table 6 lists the
-------
17
five alternatives.
TABLE 6
REMEDIAL ACTION ALTERNATIVES
Alternative 1 No Action :
Alternative 2 Groundwater Extraction and Treatment
with Air Stripping and Discharge to the
Wisconsin River
Alternative 3 In-Situ Bioreclamation with Partial
Above Ground Treatment and Discharge
to the Wisconsin River .
Alternative 4 In-Situ Bioreclamation
Alternative 5 Active Source Control-Soil Vapor .
Extraction
C. Alternatives " ' . .
Alternative 1 - No Action .
The No Action Alternative is evaluated as required by the NCP.
Under this alternative, no response action would be taken beyond
the Interim remedy.
The interim remedy extraction well will provide a barrier to
contaminant migration from the landfill source to CW6, ultimately
resulting in the elimination of contaminant impact at this well.
The time to achieve protection of CW6 under this alternative
depends on the rate of aquifer purging provided by Well CW6
pumping. Computer simulation of the No Action alternative for
the landfill source shows that a groundwater divide would be
present in the vicinity of the ponded area in Bos Creek between
CW6 and the landfill extraction well. Contaminants on either
side of this divide would migrate north to CW6 or south to the
extraction well. Given the pumping rates assumed for these
simulations and the initial mass distribution, a time period of
approximately 10 years is estimated to be necessary to achieve
contaminant concentrations below the MCL for TCE (5 ug/L) at CW6.
The period during which CW6 draws in contaminants from the
landfill source is estimated to be approximately 20 years under
projected pumping conditions.
The No Action simulation for the landfill source shows that the
extraction well at the landfill would also stop additional
-------
18
migration of contamination beneath the Wisconsin River to CW3.
A period of approximately 6 years is estimated to obtain
contaminant concentrations at CW3 less than 5 ug/L.
The simulated groundwater piezometric surface contours for the
East Well Field are shown on Figure 6. The map indicates an area
of hydraulic influence which extends south of the Wausau Chemical
property due primarily to pumping of CW3. With no CW4 pumping,
the shallow east side contaminant plumes lie within this area of
influence. The simulation shows the contaminant mass reaching
CW3 from the Wausau Chemical sources would,result in
concentrations consistently less than 5 ug/L after approximately
6.3 years.
The time during which CW3 would draw in contaminants from either
east side or west side sources is estimated to be approximately
15 years. It was assumed that the Phase I remedy extraction well
north of the landfill would he in operation, and that
contaminants in unsaturated zone soils at Wausau Chemical would
represent a grourtdwater contaminant source that declines in.
strength over an approximately 8-year period.
Probable ARARs for the No Action alternative are summarized in
Table 7. Chemical-specific ARARS identified include those
related to drinking water, groundwater, surface water and air
quality. Drinking water MCLs for VOCs can be met by stripping
tower treatment, as evidenced by actual performance data. The No
Action alternative would not comply with Chapter NR 140
requirements for responses where enforcement standards are
exceeded. Air emission limits are not anticipated to be exceeded
by any of the identified sources.
The only location-specific ARAR identified involves potential
future requirements that may be implemented under a wellhead
protection area program. No area has been designated to date and
no requirements have been identified. Action-specific ARARs
identified relate to property use at the landfill and
uncontrolled emission of toxic organics from source areas.
There is no cost or operation and maintenance (O&M) associated
with the No Action Alternative. Annual costs to operate the
present air stripper were not considered as O&M under this
alternative.
Alternative 2 - Groundwater Extraction/Above Ground Treatment
Alternative 2 involves installation of a groundwater extraction
system to address the shallow groundwater contamination in the
East Well Field originating from the Wausau Chemical facility. A
groundwater extraction and treatment system would be installed on
the Wausau Chemical property to extract contaminated water in
-------
I/
.- »_, J*. y ».!• ' *
7 maaK\>mt\r f / f
J~\ \I /i f'r-i
/
zvv
I ' /
-h-h-l-
Alternative 1
No Action
Alternative 3
Bloreclamatlon
Groundwater Extraction - 500 gpm
Source Area Recharge - 200 gpm
... LEGEND
" -v ^IIMO— Slmi»llO MIAO CONIOUII
/ rMOUCIION Mill CM) li PUVIK »l I.I <:'• («•« »<»l
/ fW IKU SUU-AIIM1.
Allernallve 2
Groundwater Extraction
Expanded ^xlracl|on System
Bloreclamatlon
Groundwater Extraction - 200 gpm
Source Area Recharge - 200 gpm
0 125 250
LAAJ 1
SCALE IN FEET
FIGURE 6
-------
TABLE 7
PROBABLE-ARARs: ALTERNATIVE 1
. - FEASIBILITY STUDY
WAUSAU WATER' SUPPLY NPL SITE
WAUSAU, WISCONSIN
Probable AM3
'Subject
Requirement/Compl i ance
CHEMICAL-SPECIFIC.
Federal
40 CFR 141.
40 CFR 264.94
National Primary Drinking Water
Standi-ds
Groundwater Concentration Limits
State
NR 109 WAC
NR 140 WAC
Safe Drinking Water
Groundwater Quality
NR 104 WAC
NR 105 WAC
NR 445 WAC
Uses and Designated Standards for
Interstate Waters
Surface Water Quality Criteria
for Toxic Substances
Control of Hazardous Pollutants
.Enforceable numerical -standards- for -pub! ic w-a'ter
.•supplies.' .Standards for VOCs. .can. be met using. ;*:ke:
'tower stripping treatment. '.••'. . : . . . .-
..Enforceable limits for substances in groundwater' .
' .released from a solid waste management unit-perrit:e:
• under RCRA. May be considered relevant and 'acprcpria-t?
:for.the former City Landfill. Anticipate .meeri-g. i --its
.in the long term as a result of aquifer purging :.y
existing production and remediation wells.
..Establishes drinking water-standards for'public .ater
supply. Applies to Wausau Water Utility. State,
standards are not more stringent than. Federal; "CLs. . .
'Standards for VOCs can be met by the water-u.til-ity.
Establishes numerical standards for c: - rsntrati-sh cf :
-.substances in groundwater. Different -levels' of -: r «;:'::-
.- are .appropriate when .Preventive Action Limits (• ?-A-'L•;..:-'
.'. Enforcement Standards; (ES.) are exceeded. - Anticipate•'
•continually lower contaminant concentrations in t.-.e\
"aquifer'as a result of existing production and .-'
•remediation (including Phase I remedy) -wells':-. Lac< :•'
.additional active groundwater remediation.may net :
-------
TABLE 7 (Continued)
PROBABLE ARARs: ALTERNATIVE 1
FEASIBILITY STUDY
UAUSAU WATER SUPPLY NPL 'SITE.
UAUSAU. WISCONSIN .
Probable
Subiect
Recui refnent/Comoliance
ACTION-SPECIFIC
Federal
40 CFR 264.117
State
NR 400-499
NR 500-520
Post-Closure Property Use
Air Quality Management.
Solid and Hazardous'. Waste
Management. . .. . •'
May be relevant and appropriate for former City
No restricted uses are proposed.
Source area emissions may be subject to requirer.srts :.'.
emissions under No'Action are not anticipated t: excee:
established limits. . '!.'...
Final property use requirements may apply for the fcr-r.er
City Landfill performance and operational criteria
regulate emissions of toxic substances to air. Air
emissions under No Action do not appear to exceei H--. r.s.
-------
19
close proximity to the area of greatest soil contamination (see
Figure 7). The system would include a cluster of wells designed
to extend the zone of influence beneath the City filtration plant
and the Wausau Chemical building, as well as to the east of the
facility where contaminants have migrated due to the effects of
aquifer recharge from the Wisconsin River.
Extracted water would be pumped to an air stripper for treatment
of VOCs prior to discharge to the Wisconsin River. Off-gas
treatment would be included in the treatment process and would
involve vapor phase activated carbon units to treat gases and off
site regeneration of carbon and destruction of contaminants. It
is estimated that the system flow rate would be approximately
300-500 gpm.
Implementation of this alternative is expected to limit migration
of contaminants from Wausau Chemical to CW3. Contaminant
transport simulations of this alternative shows that at total
system pumping rates of 200 and-500 gpm, contaminant
concentrations at CW3 resulting for migration form the Wausau
Chemical source would be less than 5 ug/L in approximately 5.2
years. However, complete restoration of the aquifer on the east
side of the river would require 12 years.
Contamination in the deep groundwater plume originating at the
former City landfill/Marathon Electric source area is not
anticipated to be influenced by pumping of the east side
extraction well system. Thus, the time to achieve protection of
CW3 under this alternative is not anticipated to be substantially
different from that estimated under the No Action alternative,
because the time to achieve aquifer purging under both
alternatives is determined by the time required to remediate the
deep TCE plume. However, the magnitude of contaminant
concentrations affecting Production Well CW3 is expected to
decrease, because the contribution of contaminants from the east
side source will be reduced.
Costs for Alternative 2 are summarized in Table 12. Major
capital cost items include groundwater extraction wells and
header system, pumps, controls, stripping tower and discharge
line. Major operation and maintenance items include energy
costs, sampling and monitoring, analytical laboratory, routine
systems inspection and maintenance, and reporting. Capital costs
are estimated to be $480,000. Annual operation and maintenance
costs are estimated to be approximately $120,000. The 10-year
present worth (10% discount rate) associated with the above costs
is $1,330,000.
Probable ARARs for Alternative 2 are summarized in Table 8.
Chemical-specific ARARs include drinking water, groundwater,
surface water and air quality standards, criteria or limits.
These include drinking water MCLs and NR 140 standards. Drinking
-------
WISCONSIN RIVIH
LEGEND
. IANH
STORAtit AREA
NORTH RIVER DRIVE
WATER
TREATMENT
PLANT
EXISTIN
STRIPPING TOWER
4, 4* \^ EXISTING SURGE TANK
STRIPPING TOWERS—-<•
>v ^-PROPOSED STRIPPING TOWER
GROUNOWATER
I EXTRACTION HEADER
'
WAUSAU
ENERGY
SECOND STREET
WERGIN
CONSTRUCTION
I
fWMStO UMMOUAUI IllUCIln Mil IOU1IM
I1ISIIM MMICIMI. nOOUCHM MU LOUIIM
timiNG IMWIIIIU. fMOUCIION MU lOCAIIOK
CMli SICIIO* IOC11I(M
NOfOifO OISCMMU UM
— IIU CIISIINC STORM S£WU
O HAJUKjlt
,CWJ
200
THIRD S1HEET
FIGURE 7
-------
TABLE 12
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 2
FEASIBILITY STUDY
. WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
. CAPITAL COSTS
Item • ' .• • ' . Cost
Groundwater Extraction System '..'[.'•' $ 70,000
.Stripping Tower and Appurtenances '••',: . ' $110,000
Vapor Phase Carbon Unit and Appurtenances $ 50,000
Discharge System . •;.. . $ 40,000
Utilities, Excavation Spoils Management . $ 15,000
: Capita! •Faci-Hties Subtotal $285,000
Engineering Design (15S) . . . . ; : $ 45,000
Contract and Project Administration (25%) $ 70;,OOP
•"'••:' ...: Capital Subtotal $400,000
Contingencies (20%) . ; •"•'.•''•;-;'/ $ 80,000.
. \ '/-. Capital Total $480,000
\ • ANNUAL OPERATION.AND.MAINTENANCE COSTS . .
•.'••'' ••'' .' Y. ;' .First Year . Subsequent Yea-s
Water Levels . $ 5,000 $ 5/0'QO
Water Quality • . $26,000 $ V8,000
Flow Monitoring . •'"•'. $ 3,000 $ 3,000
Energy. $ 6,000 $ 6,000
General O&M Labor . .. : $ 20,000 . $ 20,000
Reporting and Administration $ 30,000 $ 30,000
Carbon Purchase and Regeneration $ 30,000 . $. 30,000
O&M-Subtotal $120,000 .$102,000
Contingencies (20X) $24.000 . $20.000
O&M Total $144,000 . :.. $122,000
r -"... • ' ' ..•;'..'•
12-YEAR PRESENT WORTH .- ..-'•'
Present Worth of Capital (not discounted) .• . . ..$480,000
Present Worth of 0 & M (10% discount rate) . $850..OOP
Present Worth Total.. . . . $1,330,000
-------
20
water MCLs for VOCs can be met by the water utility. The proposed
groundwater response actions would satisfy response requirements
of NR 140. Meeting water quality-based effluent limits
established to meet water quality criteria should be feasible
using packed tower stripping. Meeting compound-specific limits
for VOC emissions to air would be feasible based on anticipated
concentrations and pumping rates, regardless of whether or not
off-gas controls are used.
Location-specific ARARs include possible wellhead protection
requirements, and flbodplain activity requirements. Action-
specific ARARs include requirements for well construction and
plumbing system standards, treatment system plan review,
obtaining a surface water discharge permit, VOC emissions limits
and construction and industrial safety. No difficulties in
achieving compliance with any of these have been identified.
Implementation of this alternative is not expected to be a
problem. The technology is readily available, conventional, and
well demonstrated. Construction is straight forward and no
unusual features are anticipated to be required for the system.
Coordination between U.S. EPA and the City of Wausau will be
required to accomplish implementation of the system.
Alternative 3 - In-Situ Bioreclamation With Partial Treatment and
Discharge
Alternative 3 is an in-situ method for remediation of the shallow
east side groundwater contaminant plume. Groundwater would be
extracted, a portion would be treated and discharged to the
Wisconsin River and the remainder would be supplemented with
nutrients and recharged to the aquifer to enhance microbially-
mediated degradation of contaminants in-situ.
A line of groundwater extraction wells would be installed around
the north and east portions of the Wausau Chemical property. A
conceptual system layout is shown on Figure 8. The placement of
barrier wells is intended to surround the section (downgradient
of the Wausau Chemical sources) of the plume where volatile
chlorinated hydrocarbon concentrations greater than
approximately 200 ug/L were observed. Extracted groundwater
would be pumped to a common header. The header would convey
water back toward the treatment system. The flow would be split
between the treatment system and recharge to groundwater.
For a groundwater extraction rate of 500 gpm, approximately 300
gpm would be treated using VOC stripping and discharged to the
Wisconsin River. A VOC stripping tower with.off-gas controls
would be used for treatment. Carbon adsorption would be provided
ifor off-gas treatment. . .
-------
WISCONSIN RIVER
LEGEND
EXISTING EXTRACTION
WELLS (TVP.)
FORMER TANK
STORAGE AREA
TREATMENT
PLANT
EXISTING
STRIPPING TOWER
EXISTING SURGE TANK
PROPOSED STRIPPING TOWER
STRIPPING TOWERS—0
o
GROUNOWATER
EXTRACTION
HEADER
WAUSAU
ENERGY
SECOND STREET
WERGIN
CONSTRUCTION
CMUNMATU IINWIIUI MIL lOUIIUI
[11ST IK HWICIfJU. MtOUCtUm MIL LOCAIION
(•) HISIIM IMUSTtlAl rMOUCIIM MIL IOUIIM
HOTOSIO OlSOMKf II*
—• KOMJfO IIIMCTIIM NCAMI
•» rtorosu mrmuiiM KUOU
Or
CB05S SfCIKM LOCAIICm
IIIiTIMC 5IOM UWU
HANHOLf
200
THIRD STREET
FIGURED
-------
TABLE 3
PROBABLE ARARs: ALTERNATIVE 2
FEASIBILITY STUDY
UAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN .
Probable ARAB
Subject
Requi rement/Compli ance
Federal
40 CFR 141
40 CFR 264.94
CHEMICAL-SPECIFIC
National Primary Drinking Water
Standards
Groundwater Concentration Limits
CWA Sec. 304(a)(l) Ambient Water Quality Criteria
40 CFR 50.6
National Primary and Secondary
Ambient Air Quality Standards
Enforceable numerical standards for public water
supplies. Standards for VOCs can be met using packed
tower stripping treatment.
Enforceable limits for substances in groundwater
released from a solid waste management unit permitted
under RCRA. Anticipate meeting limits in the long tera
as a result of aquifer purging by production and
remediation wells.
Concentration values considered to be protective of
aquatic species, based on reported bioassay results.
Available limits can be met with treatment.
Participate standards may apply to dust-generating
construction activities. Standard control practices
should be effective.
State
NR 109 WAC
NR 140 WAC
Safe Drinking Water
Groundwater Quality
NR 102 WAC
NR 104 WAC
NR 105 WAC
NR 106 WAC
NR 445 WAC
Surface Water Quality Standards
Establishes drinking water standards for public water
supply. Standards for VOCs can be met by the water
utility. State standards are not more stringent than
Federal MCLs.
Establishes numerical standards for concentration of '
substances in groundwater. Different levels of response"
are appropriate when Preventive Action Limits (PAL) cr
Enforcement Standards (ES) are exceeded. Anticipate
continually lower contaminant concentrations in the
aquifer due to purging wells. Proposed system
accelerates overall contaminant removal rate.
Establishes water quality standards for streams. Applies
to the Wisconsin River. Stream standards can be
maintained.
Uses and Designated Standards for Mandates that the Wisconsin River shall meet
Interstate Waters criteria for fish and aquatic life and recreational use.
Criteria can be net with a treated discharge.
Surface Water Quality Criteria
for Toxic Substartces
Control of Hazardous Pollutants
Establishes numerical water quality criteria for
toxic substances. NR 106 specifies methods for
calculating water quality-based effluent limits, Limits
can be met with a treated discharge.
Establishes hourly or annual emission rate limits for
specific substances. Estimated stripping tower emissions
are lower than identified limits.
LOCATION-SPECIFIC
Federal
Executive Order
11988
SDWA Sec. 1428
Floodplain Management
Wellhead Protection Areas
Requires that federal agencies identify and evaluate
potential effects of actions on floodplains. HO
appreciable adverse effects have been identified.
Requirement for states to develop program for
establishing wellhead protection areas. No specific
requirements are known at this time. Construction and
operation^of groundwater extraction and treatment system
should not conflict with possible future requirements.
-------
Probable ARAR
TABLE 8 (continued)
PROBABLE ARARs: ALTERNATIVE 2
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
UAUSAU, WISCONSIN
Subject
Requirement/Corneliance
State
Chapter 30,
Statutes
Federal
CWA Section 301;
.40 CrR 122. /.
.40 CFR .264.117
29. CFR 1910-
State . .•
NR 108 'WAC
NR -200 WAC
NR. 219 WAC
NR 220 WAC
NR 400-499
Protection of Floodplains
Regulates construction in floodplains. Some construction
may take place within floodplain boundary. Outfall
construction is specifically allowed. Obtaining approval
for extraction wells or pipelines is considered feasible.
ACTION-SPECIFIC
Protection of Surface Water
Quality
Post-Closure Property Use
Protection of Hazardous Waste
Site Workers
Technology-based effluent limits may apply
to surface water discharge.
In general, use must not be allowed to disturb the
integrity of the final landfill cover. Deed restrictions
may be appropriate to limit use of landfill property.
Establishes requirements for training, protective
equipment, waste handling, personnel monitoring, and
emergency procedures for hazardous waste site workers.
Establishes procedures for submittal and review of
plans and specifications for treatment facilities.
No problems are anticipated.
Establishes requirements for design and
construction of wells and appurtenances. Compliance with
requirements is not anticipated to present difficulties.
Application for Discharge Permits Establishes procedures for WPDES permit application. No
. problems are anticipated.
Requirements for P.lans and
Specifications for Wastewater
Facilities
Well Construction and Pump
Installation
Analytical Test Methods and
Procedures
Categories and Classes of Point
Sources
.Air Quality Management
ILHR 81-84 WAC State Plumbing Co'de
ILHR 50-53 WAC. . State.Building Code
Establishes acceptable methods for analyzing
samples from point sources discharging to surface water.
Standard procedures are appropriate for the remedy.
Establishes categories of point sources. Surface
water discharge from treatment system would likely be
subject to 8ATEA requirements. VOC stripping tower
treatment should satisfy this requirement.
HR 400 series regulations covers the range of Wisconsin
air qt/ality requirements. Estimated VOC emission rates
from stripping tower are estimated to be lower than
limits where controls would be required.
Design, construction and materials for piping, plumbing
and sewer connection associated with extraction system
and discharge must comply with requirements. State
review and approval is required.
Design and construction of structures must comply with
requirements.
IND 1 WAC
INO 6 WAC .
General Industrial Safety
Construction and operation must comply with safety
requirements.
Industrial Safety.for Trenches Construction must comply with safety requirements.
and Excavation
-------
21
The 200 gpm not treated above ground and discharged would be
supplemented with nutrients and recharged over the southern end
of the Wausau Chemical property. Infiltration trenches filled
with gravel would effectively distribute water over the area.
Nutrients such as nitrogen or phosphorus would be added. Where
aerobic conditions are desired, hydrogen peroxide would be fed.
A carbon and energy source such as a methanol may be required to
support heterotrophic growth.
Laboratory and field study would be required to confirm
feasibility at the site and determine the required operating
environment and conditions. It is anticipated that planning,
execution and analysis of laboratory studies could be
accomplished within a 6-month period, and that planning,
execution and analysis of field pilot testing program could be
accomplished within a 1.5-year period, depending on the scope and
complexity of studies and on the outcome of early test phase
activities. Overall, a two-year period could be required for
testing and demonstration.
Technologies described in this alternative are expected to
provide protection of CW3 by creating a barrier to the migration
of most of the contaminants in the shallow east side plume, in
addition to aquifer restoration. This alternative is not
expected to affect the deep contaminant plume originating on the
west side.
Computer simulation of the alternative shows that the proposed
line of extraction wells can create an effective hydraulic
barrier to contaminant migration to CW3 if pumping rates are high
enough. The simulated head contour map shown on Figure 6 shows
this occurs at a total system pumping rate of 500 gpm and an
infiltration rate of 200 gpm at the source. Contaminant
transport simulation shows that PCE concentrations at CW3 would
decrease below 5 ug/L after approximately 2.5 years. Complete
aquifer purge time for the east side groundwater under this
alternative could not be estimated using the contaminant
transport model. The simulation shows that the groundwater mound
resulting from the'recharge may force a small amount (<1%) of
contamination to migrate around the east side of the extraction
system. However, the mass not captured is not likely to result
in detectable concentrations at CW3. Pumping at lower rates or
with widely spaced wells may not provide the desired hydraulic
control.
Costs for Alternative 3 are summarized in Table 13. Major
capital cost items include laboratory and field testing programs,
system review and approval, extraction well and header system,
stripping tower, carbon adsorber, foundations, nutrient feeding
system, recharge trench and piping, controls and utilities and
discharge piping. Major operation and maintenance cost items
include energy costs, sampling and monitoring, analytical
-------
TABLE 13
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 3
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
CAPITAL COSTS
Item Cost
Groundwater Extraction System $ 95,000
Stripping Tower and Appurtenances $110,000
Vapor Phase Carbon Unit and Appurtenances $ 50,000
Discharge System $ 40,000
Infiltration/Nutrient System $ 90,000
Utilities and Excavation Spoils Management $ 10,000
Lab and Pilot Testing $200.000
Capital Facilities Subtotal $595,000
Engineering Design (15%} $ 90,000
Contract and Project Administration (25%) $150,000
Capital Subtotal $825,000
Contingencies (20S) $165,000
Capital Total $990,000
ANNUAL OPERATION AND MAINTENANCE COSTS
First Year Subsequent Years
Water Levels $ 5,000 $ 5,000
Water Quality $ 26,000 $ 8,000
Flow Monitoring . $ 5,000 $ 5,000
Energy $ 6,000 $ 6,000
General O&M Labor $ 40,000 $ 40,000
Reporting and Administration $ 30,000 $ 30,000
Chemicals, Carbon and Regeneration $ 40.000 $ 40,000
O&M Subtotal $152,000 $134,000
Contingencies (20%) $ 30.000 $ 27.000
O&M Total $182,000 $161,000
6-YEAR PRESENT WORTH
Present Worth of Capital (not discounted) $990,000
Present Worth of 0 & M (10X discount rate) $720.000
Present Worth Total $1,710,000
-------
22
laboratory, routine systems inspection and maintenance, and
reporting. For costing purposes, it is assumed a time period of
six years would be required. Capital costs are estimated to be
$990,000. The annual operation and maintenance costs are
estimated to be approximately $160,000. The 6-year present worth
(10% discount rate) associated with the above costs is
$1,710,000.
Probable ARARs for Alternative 3 are summarized in Table 9.
Chemical-specific ARARs for drinking water, groundwater, surface
water and air were identified for this alternative. These
include drinking water MCLs and NR 140 groundwater standards.
Drinking water MCLs can be met by stripping tower treatment at
the water utility. The aquifer restoration effort would be
consistent with NR 140 requirements for remedial responses to
groundwater contamination. Surface water criteria compliance
would be feasible using stripping tower treatment to meet water
quality-based effluent limits for water discharged to the
Wisconsin River. VOC emission rate limits for specific compounds
would be attainable for the stripping tower emissions.
Location-specific ARARs include floodplain and possible wellhead
protection area requirements. Action-specific ARARs for the
groundwater extraction, treatment and discharge systems are the
same as for Alternative 2. No particular compliance difficulties
are anticipated. To achieve compliance with State requirements
regarding introduction of materials into groundwater or on land
(including injection well and infiltration system restrictions),
a demonstration that significant adverse effects will not result
would be required.
Implementation of the extraction wells and above ground treatment
portion of this alternative is not expected to be a problem. The
major uncertainty with this technology is related to the ability
to stimulate bacteria to degrade the compounds of concern. The
technology is not well demonstrated for the contaminants found at
the site.
Alternative 4 - In-Situ Bioreclamation
Alternative 4 is an in-situ method for remediation of the shallow
east side groundwater utilizing biodegradation of contaminants in
the groundwater. Alternative 4 is similar to Alternative 3,
except all extracted groundwater would be recharged back to the
aquifer. This alternative provides for rapid restoration of the
aquifer and eliminates the costs associated with above ground
treatment as with Alternative 3.
Under Alternative 4, groundwater would be extracted, supplemented
with nutrients and recharged to the aquifer to enhance
microbially-mediated contaminant degradation in-situ. A line of
-------
TABLE 9
PROBABLE ARARs: ALTERNATIVE 3
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
UAUSAU, WISCONSIN
Probable ARAR
Subject
Requireinent/Compi iance
CHEMICAL-SPECIFIC
Federal
40 CFR 141
40 CFR 264.94
National Primary Drinking Water
Standards
Groundwater Concentration Limits
CWA Sec. 304(a)(l) Ambient Water Quality Criteria
40 CFR 50.6
National Primary and Secondary
Ambient Air Quality Standards
Enforceable numerical standards for public water
supplies. Standards can be met using stripping tower
treatment.
Enforceable limits for substances in groundwater
released from a solid waste aanagement unit permitted
under RCRA. Anticipate continually decreasing
contaminant concentrations in the aquifer as a result of
pumping wells and in-situ contaminant degradation.
Concentration values considered to be protective of
aquatic species, based on reported bioassay results.
identified criteria can be met with treated discharge.
Particulate standards may apply to dust-generating
construction activities. Standard control measures
should be effective.
State
NR 109 WAC
NR 140 WAC
NR 102 WAC
NR 104 WAC
NR 105 WAC
NR 106 WAC
NR 445 WAC
Safe Drinking Water
Groundwater Quality
Surface Water Quality Standards
Establishes drinking water standards for public water
supply. VOC standards can be met using stripping tcwer
treatment.
Establishes numerical standards for concentration of
substances in groundwater. Different levels of response
are appropriate when Preventive Action Limits (PAL) or
Enforcement Standards (ES) are exceeded. Anticipate
continually decreasing contaminant concentrations in the
aquifer as a result of pumping wells and in-situ
contaminant degradation.
Establishes water quality standards for streams.
Standards can be maintained with a treated discharae.
Uses and Designated Standards for Mandates that the Wisconsin River shall meet
Interstate Waters . criteria for fish and aquatic life and recreational use.
Criteria can be met with a treated discharge.
Surface Water Quality Criteria
for Toxic Substances
Control of Hazardous Pollutants
Establishes numerical water quality criteria for
toxic substances. NR 106 specifies methods for
calculating water quality-based effluent limits.
Criteria can be met with a treated discharge.
Establishes hourly or annual emission rate limits for
specific substances. Estimated VOC emission rates for
stripping tower are lower than limits where controls
would be required.
LOCATION.SPECIFIC
Federal
Executive Order
11988
Floodplain Management
Requires that federal agencies identify and evaluate
potential effects of actions on floodpjains. No
appreciable adverse effects have been identified.
-------
TABLE 9 (Continued)
PROBABLE ARARs: ALTERNATIVE 3
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
Probable A
Subject
Reauirement/Compliance
SDWA Sec. 1428
State
Chapter 30
Statutes
NR 115-117 MAC
Federal
CWA Section 301;
40 CFR 122
40 CFR 264.117
40' CFR 147
29 CFR 1910
State
NR 108 WAC
NR 112 WAC
NR 200 WAC
NR 214 WAC
NR 219 WAC
NR 220 WAC
Wellhead Protection Areas
Protection of Floodplains
Requirement for states to develop program for
establishing wellhead protection areas. No specific
requirements have been identified at this time.
Regulates construction in floodplains. Some construction
may take place within floodplain boundary. Outfall
construction is allowed. Obtaining approval for wells,
pipelines and recharge systems is considered feasible.
ACTION-SPECIFIC
Protection of Surface Water
Quality
Post-Closure Property Use
Underground Injection
Protection of Hazardous Waste
Site Workers
Technology-based effluent limits may apply
to surface water discharge. The proposed stripping tower
treatment should satisfy requirements.
In genera.1, use must not be allowed to disturb the
integrity of the final landfill cover. Deed restrictions
may Be appropriate to limit use of the landfill property.
Wisconsin underground injection control program prohibits
the use of injection wells except for heat .pump return
flow. Federal code reflects the State's general
prohibition.
Establishes requirements for training, protective
equipment, waste handling, personnel monitoring, and
emergency procedures for hazardous waste site workers.
Requirements for Plans and
Specifications for Wastewater
Facilities
Well Construction and Pump
Installation
Establishes procedures for submittal and review of
plans and specifications for treatment facilities.
No difficulties in meeting requirements are anticipated.
Establishes requirements for design and
construction of wells and appurtenances. Establishes
specific prohibitions on well use, including well
disposal of solid waste, sewage or surface water
drainage. Various sections apply to groundwater
extraction wells and extraction/ injection systems.
Approval for the proposed activities is considered
feasible under existing code provisions.
Application for Discharge Permits Establishes procedures for WPOES permit application. No
difficulties are anticipated for surface water discharge.
Approval for groundwater discharge may be time-consuming.
Land Application and Disposal of
Liquid Industrial Wastes and
By-Products
Analytical Test Methods and
Procedures
Categories and Classes of Point
Sources
Establishes design and construction criteria for
land disposal systems. Prohibits discharge of
toxic pollutants or hazardous waste to land (without
demonstration that no pollution will result). Prohibits
underground injection of pollutants, surface drainage or
clear water waste through a well. Prohibits location of
land disposal system in a floodway. Approval for the
proposed activities is considered feasible under existing
code provisions.
Establishes acceptable methods for analyzing
samples from point sources discharging to surface waten
Standard procedures would be appropriate for routine
system monitoring.
Establishes categories of point sources. Surface
water discharge from treatment system would likely be
subject to BATEA requirements. Stripping tower treatment
would likely meet this requirement.
-------
TABLE 9 (Continued)
PROBABLE ARARs: ALTERNATIVE 3
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
Probable ARAR
Subject
Reauireitient/Conipl iance
NR 400-499 WAC
NR 500-520 WAC
ILHR 81-84 WAC
ILHR 50-53 WAC
I NO 1 WAC
INO 6 WAC
Air Quality Management
Solid and Hazardous Waste
Management
State Plumbing Code
State Building Code
General Industrial Safety
Industrial Safety for Trenches
and Excavation
NR 400 series regulations covers the range of Wisconsin
air quality requirements. Estimated VOC emission rates
from stripping tower are below limits where controls
would be required.
NR 500 to 520 regulations cover the range of Wisconsin
solid waste management requirements. Landfill
performance and operational criteria regulate emissions
of toxic substances to air. VOC emissions from the
landfill were not identified as a health risk.
Design, construction and materials for piping, plumbing
and sewer connection associated with extraction system
and discharge must comply with requirements. State
review and approval is required. No difficulties in
meeting requirements are anticipated.
Design and construction of structures must comply with
requirements.
Construction and operation must comply with safety
requirements.
Construction must comply with safety requirements.
-------
23
groundwater extraction wells would be installed around the
northern and eastern portions of he Wausau Chemical property.
The conceptual extraction and recharge system layout is the same
as that developed for Alternative 3 (Figure 8). The
groundwater extraction and recharge rates and considerations
regarding the addition of nutrients and other enhancements to
recharge water are the same as those discussed for Alternative 3.
Computer simulation of the alternative shows that the proposed
line of extraction wells can not provide complete hydraulic
control of the extraction/recharge system at any pumping rate.
Contaminant transport simulation shows that PCE concentrations at
CW3 would decrease below 5 ug/L after approximately 2.5 years.
As with Alternative 3, complete aquifer purge time for the east
side groundwater under this alternative could not be estimated
using the contaminant transport model.
The simulation also shows that the groundwater mound resulting
from the recharge causes approximately 5% of the contaminant mass
to migrate around the east side of the extraction system to CW3 •,
(see Figure 6). The actual recapture efficiency will depend on
such factors as the specific system configuration, localized
variations in aquifer properties, extraction/recharge rates and
operating conditions, and local hydrologic factors, such as
precipitation, runoff and infiltration rates. Achieving a 100
percent recapture efficiency is not considered feasible.
Costs for Alternative 4 are summarized in Table 14. Major
capital cost items include laboratory and field testing programs,
system review and approval, extraction well and header system,
nutrient feeing system, recharge trench and piping, controls and
utilities. Major operation and maintenance cost items include
energy costs, sampling and monitoring,, analytical laboratory,
routine systems inspection and maintenance, and reporting. As
with Alternative 3, remediation period estimates were not
obtained using the contaminant transport model. It was assumed
that Alternative 4 would require more time than Alternative 3,
and less time than Alternative 2 (due to in-place contaminant
degradation) to achieve remedial objectives. A period of 9 years
was assumed for costing purposes. Capital costs are estimated to
be $710,000. The annual operation and maintenance costs are
estimated to be approximately $112,000. The 9-year present worth
(10% discount rate) associated with the above costs is
$1,380,000.
Probable ARARs for Alternative 4 are summarized in Table 10.
Chemical-specific ARARs for drinking water, groundwater, surface
water and air were identified for this alternative. These
include drinking water MCLs and MR 140 groundwater standards.
The aquifer restoration effort would be consistent with
requirements for responses to groundwater contamination under KR
140.
-------
TABLE 10
PROBABLE ARARs: ALTERNATIVE 4
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU. WISCONSIN
Probable ARAR
Subject
Requi rement/Coflioliance
CHEHICAL-SPECIFIC
Federal
40 CFR 141
40 CFR 264.94
National Primary Drinking Water
Standards
Groundwater Concentration .Limits
CWA Sec. 304(a)(l) Ambient Water Quality Criteria
40 CFR 50.6 National Primary and Secondary
Ambient Air Quality Standards
Enforceable numerical standards for public water
supplies. Standards can be met using stripping tower
treatment.
Enforceable limits for substances in groundwater
released from a solid waste management unit permitted
under RCRA. Anticipated continually decreasing
contaminant concentrations in the aquifer as a result
pumping wells and in-situ contaminant degradation.
Concentration values considered to be protective of
aquatic species, based on reported bioassay results.
Particulars standards may apply to dust-generating
construction activities. Standard control measures
should be effective.
of
State
NR 109 WAC
NR 140 UAC
NR 102 WAC
NR 104 UAC
NR 105 WAC
NR 106 WAC
NR 445 WAC
Safe Drinking Water
Groundwater Quality
Surface Water Quality Standards
Uses and Designated Standards for
Interstate Waters
Surface Water Quality Criteria
for Toxic Substances
Control of Hazardous Pollutants
Establishes drinking water standards for public water
supply. VOC standards can be met using stripping tower
treatment.
Establishes numerical standards for concentration of
substances in groundwater. Different levels of response
are appropriate when Preventive Action Limits (PAL) or
Enforcement Standards (ES) are exceeded. Antic:sate
continually decreasing contaminant concentrations in the
aquifer as a result of pumping wells and in-situ
contaminant degradation.
Establishes water quality standards for streams.
Standards can be maintained with a treated discharge.
Mandates that the Wisconsin River shall meet
criteria for fish and aquatic life and recreational use.
Criteria can be met with a treated discharge.
Establishes numerical water quality criteria for
toxic substances. NR 106 specifies methods for
calculating water quality-based effluent limits.
Criteria can be met with a treated discharge.
Establishes hourly or annual emission rate limits 'or
specific substances. Estimated VOC emission rates fcr
stripping tower or soil gas extraction systems are icwer-
than limits where controls would be required.
Federal
Executive Order
11988
Floodplain Management
LOCATION-SPECIFIC
Requires that federal agencies identify and evaiu
potential effects of actions on floodplains. NO
appreciable adverse effects have been identified.
-------
TABLE 10 (Continued)
PROBABLE ARARs: ALTERNATIVE 4
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
Probable ABAR
Subject
Requirement/Corcpliance
SOWA Sec. 1428
State
Chapter 30
Statutes
NR 115-117
Wellhead Protection Areas
Protection of Floodplains
Requirement for states to develop program for
establishing wellhead protection areas. No specific
requirements have been identified at this time.
Regulates construction in floodplains. May apply.
to remedial construction activities. Some construction
may take place within floodplain boundary. Outfall
construction is allowed. Obtaining approval for wells,
pipelines and recharge systems is considered feasible.
ACTION-SPECIFIC
Federal
CWA Section 301;
40 CFR 122
Protection of Surface Water
Quality
40 CFR 264.117 Post-Closure Property Use
40 CFR 147
29 CFR 1910
State
NR 103 WAC
NR 112 WAC
NR 200 WAC
NR 214 WAC
NR 219 WAC
Underground Injection
Protection & Hazardous Waste
Site Workers
Requirements for Plans and
Specifications for Wastewater
Facilities
Well Construction and Pump
Installation
Application for Discharge Permits
Land Application and Disposal of
Liquid Industrial Wastes and
By-Products
Analytical Test Methods and
Procedures
Technology-based effluent limits may apply
to surface water discharge. The proposed stripping tow=r
treatment should satisfy requirements.
In general, use must not be allowed to disturb the
integrity of the final landfill cover. Soil gas''
extraction system should not be a prohibited use. Deed
restriction may be appropriate to limit use of the
landfill area.
Wisconsin underground injection control program prohibits
the use of injection wells except for heat pump return
flow. Federal code reflects the State's general
prohibition.
Establishes requirements for training, protective
equipment, waste handling, and emergency procedures for
hazardous waste site workers.
Establishes procedures for submittal and review of
plans and specifications for treatment facilities.
No difficulties in meeting requirements are anticipated.
Establishes requirements for design and
construction of wells and appurtenances. Establishes
specific prohibitions on wen use, including well
disposal of solid waste, sewage or surface water
drainage. Various sections apply to groundwater
extraction wells and extraction/ injection systems.
Approval for the proposed activities is considered
feasible under existing code provisions.
Establishes procedures for WPOES permit application. No
difficulties are anticipated for surface water discnar:e.
Approval for groundwater discharge may be time-consuming.
Establishes design and construction criteria for
land disposal systems. Prohibits discharge of
toxic pollutants or hazardous waste to land (without
demonstration that no pollution will result). Prohibits
underground injection of pollutants, surface drainage or
clear water waste through a well. Prohibits location of
land disposal system in a floodway. Approval for the
proposed activities is considered feasible under existing
code provisions. • '
Establishes acceptable methods for analyzing
samples from point sources discharging to surface water.
Standard-procedure would be appropriate for routine
system monitoring.
-------
TABLE 10 (Continued)
PROBABLE ARARs: ALTERNATIVE 4
FEASIBILITY STUDY
WAUSAU UATER SUPPLY NPL SITE
WAUSAU. WISCONSIN
Probable ARAR
Subject
Reouirement/Comoliance
NR 220 WAC
NR 400-499
NR 500-520
ILHR 50-53 WAC
INO 1 WAC
I NO 6 WAC
Categories and Classes of Point
Sources
Air Quality Management
Solid and Hazardous Waste
Management
ILHR 81-84 WAC State Plumbing Code
State Building Code
General Industrial Safety
Industrial Safety for Trerrches
and Excavation
Establishes categories of point sources. Surface
water discharge from treatment system would likely be
subject to BATEA requirements. Stripping tower treatment
would likely meet this requirement.
NR 400 series regulations covers the range of Wisconsin
air quality requirements. Estimated VOC emission rates
for stripping tower or soil gas extraction systems are
below limits where controls would be required.
NR 500 to 520 regulations cover the range of Wisconsin
solid waste management requirements. Landfill
performance and operational criteria regulate emissions
of toxic substances to air. VOC emission from the
landfill would be controlled, but actual emission rates
would likelv be higher than would be the case under the
No Action alternative.
Design, construction and materials for piping, plumbing
and sewer connection associated with pump house and
discharge must comply with requirements. State review
and approval is required. No difficulties in meeting
requirements are anticipated.
Design and construction of structures must comply with
requirements.
Construction and operation must comply with safety
requirements.
Construction must comply with safety requirements.
-------
TABLE 14
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 4
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
CAPITAL COSTS
Item Cost
Groundwater Extraction System $120,000
Utilities and Excavation Spoils Management $ 10,000
Infiltration/Nutrient System $ 90,000
Lab and Pilot Study $200.000
Capital Facilities Subtotal $420,000
Engineering Design (15%) $ 65,000
Contract and Project Administration (25%) $105,000
Capital Subtotal $590,000
Contingencies (202) $120.000
Capital Total $710,000
ANNUAL OPERATION AND MAINTENANCE COSTS
First Year Subsequent Years
Water Levels $ 5,000 $ 5,000
Water Quality $ 26,000 $ 8,000
Flow Monitoring $ 5,000 $ 5,000
Energy $ 5,000 $ 5,000
General O&M Labor $ 30,000 $ 30,000
Reporting and Administration $ 30,000 $ 30,000
Chemicals $ 10.000 $ 10.000
O&M .Subtotal $111,000 $93,000
Contingencies (20Z) $ 22.000 $ 19.000
O&M Total $133,000 $112,000
9-YEAR PRESENT WORTH
Present Worth of Capital (not discount) $ 710,000
Present Worth of 0 & M (10X discount rate) $ 670.000
Present Worth Total $1,380,000
-------
26
Costs for Alternative 5 are summarized in Table 15. Major
capital cost items include soil gas extraction and air recharge
veils, header pipe line, blower, motor, controls and a shelter
to protect equipment. Major operation and maintenance cost items
include carbon, electricity, monitoring and analytical laboratory
costs, routine systems inspection and maintenance, and reporting.
Capital costs are estimated to be $252,000. Operation costs are
estimated to be $222,000. Present worth costs are estimated to
be $474,000. An 18-month operating period was assumed and costs
were not discounted.
Use of the City production wells as part of the remedy requires
that the cost of operating and maintaining the wells and
stripping towers be considered part of the cost of the remedy.
Costs were developed based on operating the 8-ft diameter tower
at the Wausau Water Utility. Major items include energy costs
for pumping wells and stripping towers, and operation and
maintenance of stripping towers. It was assumed that for each
City production well, the time until no more contaminants are
drawn in to a well represents the time of operation. The
estimated present worth of the City operating the two City wells
and treating the water is $260,000. Operating CW6 and treating
its water for VOC removal for 14 years accounts for $180,000.
The corresponding cost for CW3 for a 6-year operating period is
$80,000. The estimated total present .worth cost of Alternative 5
is $734,000.
Probable ARARs for Alternative 5 are summarized in Table 11.
Chemical-specific ARARs addressing drinking water, groundwater
and air quality standards were identified for Alternative 5.
These include drinking water MCLs and NR 140 groundwater
standards. Drinking water standards for VOCs can be met at the
water utility using VOC stripping tower treatment. This
alternative would meet the requirements for response under
Chapter MR 140. Meeting State emission limits can be achieved
without controls for specific organic compounds.
Location-specific ARARs include requirements related to
activities within floodplains and wellhead protection areas.
Action-specific ARARs include landfill property use restrictions.
Compliance with possible future requirements should not be a
problem.
Implementation of this alternative is not expected to be a
problem. The technology is readily available and well
demonstrated. No unusual features are anticipated with
implementation and operation of the system.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
-------
TABLE. 11
PROBABLE ARARs: ALTERNATIVE 5
FEASIBILITY .STUDY
'JAUSAU WATER SUPPLY NPL.SITE
WAUSAU. WISCONSIN
Probable ARAR
Subject
Requirement/Compliance
Federal
40 CFR 141
CHEMICAL-SPECIFIC
National Primary Drinking Water
Standards
Enforceable numerical standards for'public water
supplies. Standards for VOCs can be met at this water
utility using packed tower stripping treatment. :.
40 CFR 264.94 Groundwater Concentration Limits
40 CFR 50.6 National Primary and Secondary
Ambient Air Quality Standards
Enforceable limits for substances in grouridw'ater
released from a solid waste management unit permitted
under RCRA. Anticipate meeting limits-in the long term
as a result of aquifer purging by existing' production and
remediation (including Phase I remedy) wei'ls'..
Particulate standards may apply to dust-generating
construction activities. Standard control measures
should be effective. Extensive excavation is hot
planned. . ,
State
NR 109 WAC
NR 140 WAC
Safe Drinking Water
Groundwater Quality
NR 445 WAC
Control of Hazardous Pollutants
Establishes drinking water standards for public water
supply. State standards are not more stringent'than
Federal HCLs. Standards for VOCs can be met by -the »aitf
utility.
Establishes numerical standards for concentration of
substances in groundwater. Different levels of resoonse
are appropriate when Preventive Action Limits (PAL) or
Enforcement Standards (ES) are exceeded,. Values may be
used as remedial objectives. Anticipate-continually
lower contaminant concentrations in the aquifer as a
result of aquifer purging by existing production and
remediation (including Phase 1 remedy) wells.
Establishes hourly or annual emission rate limits for
specific substances. Emission rates on the order of 1
ib/day for individual systems would meet limits.
Federal
Executive Order
11988
SDUA Sec. 1428
State
Chapter 30
Statues
LOCATION-SPECIFIC
Floodplain Management
Wellhead Protection Areas
Protection of Floodplains
Requires that federal agencies identify and evaluate
potential effects of actions on floodplains. NO
appreciable adverse effects have been identified.
Requirement for states to develop program for
establishing wellhead protection areas. NO sDec"''c
requirements are known at this time. Implementation of
soil gas extraction systems should not conflict -itn
possible future requirements.
Regulates construction in floodplains. Proposes systems
do not appear to lie within floodplain.
-------
TABLE 11 (Continued)
PROBABLE ARARs: ALTERNATIVE 5
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
HAUSAU, WISCONSIN
Probable ARAR
Subject
Requi rement/Compliance
ACTION-SPECIFIC
Federal
40 CFR 264.117.
29 CFR 1920
State
NR 181 WAC
NR 400-499 WAC
NR 500-520 WAC
ILHR 50-53 WAC
I NO 1 WAC
INO 6 WAC
Post-Closure Property Use
Protection of Hazardous Waste
Site Workers
Hazardous Waste Management
Air Quality Management
Solid and Hazardous Waste
Management
State Building Code
General Industrial Safety
Industrial Safety for Trenches
and Excavation
In general, use. must not be allowed to disturb the
integrity of the final landfill cover. Proposed soil gas
extraction system does not appear to be a prohibited
activity.
Requirements for training, protective equipment, waste
handling, personnel monitoring, and emergency procedures
for hazardous waste site workers.
Off-gas treatment process residuals may require
management as hazardous waste.
NR 400 series regulations covers the range of Wisconsin
air quality requirements. VOC emission rates are
anticipated to be below levels where controls would be
required.
NR 500 to 520 regulations cover the range of Wisconsin
solid waste management requirements. Landfill -
performance and operational criteria regulate emissions
of explosive gases and toxic substances to air.
Explosive gases are not anticipated due to the nature of
the landfilled material. Extraction of VOCs will provide
control of emissions, but likely would increase the rate
over that expected to occur under No Action.
Design and construction of structures must comply with
requirements.
Construction and operation must comply with safety
requirements.
Construction must comply with safety requirements.
-------
24
Location-specific ARARs include floodplain and possible wellhead
protection area requirements. Action-specific ARARs for the
groundwater extraction, treatment and discharge systems are the
same as for Alternative 3.
Implementation of the extraction wells, trenching, and discharge
portion of this alternative is not expected to be a problem. The
major uncertainty with this technology is related to the ability
to stimulate existing bacteria to degrade the compounds of
concern in the groundwater. This technology is not well
demonstrated for the contaminants found at the site.
Alternative 5 - Active Source Control-Soil Vapor Extraction
Alternative 5 is a source control alternative utilizing In-situ
soil vapor extraction (SVE). to remove contaminants from
unsaturated soils thereby reducing the potential for future
contaminant releases to groundwater. Contaminants vacuumed froin
the soil, in the vapor phase, would be treated using vapor phase
carbon units, prior to release to the atmosphere. The scope of
Alternative 5 includes remediation of unsaturated soils at the
former City landfill/Marathon Electric property, Wausau Chemical
and Wausau Energy.
For the former landfill area, soil gas extraction wells would be
installed within the limits of the fill in the northern portion
of the landfill where the highest VOC concentrations have been
observed. A conceptual system layout is shown on Figure 9. A
header pipe would be installed to connect the wells to an
induction fan blower. The blower and control panel would be
housed in a small shed. It is anticipated that air recharge wells
would be required and are included in the design & cost of the
alternative.
A similar type of soil gas extraction system would be installed
on the Wausau Chemical property. Soil gas would be extracted
near the former tank storage area. This area is near the center
of high soil gas VOC concentrations observed at the site. A
second extraction area would be located near the north end of the
building. A header would connect the extraction wells to a
common blower. Air recharge wells would also be anticipated for
this system. Conceptual layout is shown on Figure 10. Pilot
study results indicate a radius of influence of approximately 85
ft. was obtained at a gas extraction rate of 72 scfm. A soil gas
extraction system would also .be installed at the Wausau Energy
property on the south side of the building. Soil types
encountered in on-site borings were similar to those encountered
at several Wausau Chemical site borings and it is therefore,
assumed that the radius of influence would be sufficient to cover
the entire facility.
-------
MARATHON ELECTRIC
FOUNDRY
APPROXIMATE
LIMITS OF FORMER
CITY LANDFILL
O
2
in
O
J
t
(
V
.LEGEND
ill
PAVEO
P
e
P80MSIO SOIL GAS (IIMCUM Mill LOCAIIM
FKOPOUD All UCMAttt UCLL LOCAIKM
C«OSS UUION IOCAIIOM
-SIM f mi ING STORK SCUIB . .
O HANHOLC
*
SUCTION
HEADER
V^'V
• J.
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—
*
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i
• .
MARATHON ELECTRIC
MANUFACTURING .
<— BLOWER. MOTOR.
^.^ J CONTROL SHEO
•*•
PROPOSED PHASE I
GHOUNDWATER
EXTRACTION
WELL
0 100
LTLTLT-
SCALE IN FEET
200
-------
WISCONSIN RIVER
STM UISIING SIMM SCHI
O HANHOU
EXISTING EXTRACTION
WELLS (TVP.)
FORMER TANK
STORAGE AREA
NORTH RIVERJ3NJVE
BLOWEH>4JOTOR.
AND CONTHOtTSHtO
WATER
TREATMENT
PLANT
EXISTING
STRIPPING TOWER
EXISTING SURGE TANK
STRIPPING TOWERS—"
BLOWER, MOTOR.
AND CONTROL SHED
SECOND STREET
WERGIN
CONSTRUCTION
morasco sou CAS [IIWCIIM MCLI IOCATIM
PHOfOilO All HCHAJ1CI MIL IOCAIION
[IISIINC MUNICIPAL PUttUCIK* MIL LOCAIION
(IISIINC INOUSIIIAL rMMCIIOM WLl LOU1IM
MOSS SCCIION IOCATIM
KCWJ
THIRD STREET
-------
25
Technologies described in this alternative would reduce the time
required to meet response objectives for groundvater clean-up,
because there will be a reduction in contaminant loading to the
aquifer, by reducing contaminant levels in the unsaturated zone
soils. However, substantial reductions in existing contaminant
concentrations in groundwater would not be expected to occur as a
result of vapor extraction at the source.
Based on computer simulations during development of the FS, it
was shown that extraction of groundwater on the east side in the
vicinity of the Wausau Chemical source area would create a
groundwater divide where contaminants would get "hung up" due to
competition for water between CW3 and the extraction system (see
discussion under Alternative 2). Because of this phenomenon,
extracting groundwater at the source results in a longer period
to purge the aquifer than allowing contaminants to flow to the
currently,operating City supply wells. It was, therefore,
determined that City supply wells CW6 and CW3 would be
incorporated into the source control alternative as the means for
addressing groundwater contamination remediation.
Computer modeling of this alternative was performed by decreasing
the contaminant loading rates from soils to zero after 1.5 years
to simulate removal of the sources. Two different computer
simulations were performed to determine the optimum pumpage rates
for the City's supply wells CW3 and CW6. It was determined that
increased pumpage of the supply wells result in a reduced time
period for remediation under this alternative.
Based on the simulation, a TCE concentration of less than 5 ug/L
could be achieved at CW6 after approximately 4.5 years. TCE
concentrations at CW3 resulting from migration from the landfill
would be less than 5 ug/L after approximately 4 years. Wells CW3
and CW6 would continue to draw in contaminants from the landfill
for 6 and 14 years, respectively. PCE concentrations at
Production Well CW3 would be reduced to less than 5 ug/L after
approximately 3.3 years and Well CW3 would no longer draw in
contaminants from the Wausau Chemical sources after approximately
5 years.
It is not anticipated that VOC emissions from the water utility
stripping towers would be higher than those assumed for modeling
of air emissions. No off-gas controls are proposed for the water
utility stripping towers considering that their operation would
produce emissions within the acceptable risk level of 10"6 and
therefore are considered representative of baseline conditions.
The soil vapor extraction systems would represent new sources.
Based on preliminary risk calculations, risks associated with new
VOC emissions in the area would need to be addressed. Vapor
phase carbon is therefore included for off-gas treatment for
these systems.
-------
TABLE 15
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 5
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
CAPITAL COSTS
Item Cost
Wells, Header and Appurtenances $ 90,000
Blower House, Controls, Utilities $ 60,000
Off-Gas Treatment (Carbon) $ 25.000
Capital Facilities Subtotal $175,000
Engineering Design (20%) $ 29,000
Contract and Project Administration (25%) $ 36.000
Capital Subtotal $210,000
Contingencies (20X) $ 42.000
Capital Total $252,000
OPERATION AND MAINTENANCE COSTS
Monitoring • $ 15,000
Energy $ 5,000
General O&M Labor $ 30,000
Reporting and Administration $ 45,000
Carbon Purchase and Treatment $ 90.000
Vapor System 18 Month O&M Subtotal $185,000
Contingencies (20X) $ 37.000
Vapor System 18 Month O&M Total $222,000
Well CW3 and Stripper - Energy $ 15,000
- O&M $ 3,000
Well CW6 and Stripper - Energy $ 21,000
-O&M $ 3.500
City Well and Stripper Annual O&M Total $42,500
PRESENT WORTH
Present Worth of Vapor System Capital (not discounted) $252,000
Present Worth of Vapor System O&M (not discounted) $222.000
Vapor System Present Worth Total $474,000
Present Worth of CW3 Cost (6 years) $ 80,000
Present Worth of CW6 Cost (14 years) $180.000
City Well and Stripper Present Worth Total $260,000
Alternative 5 Present Worth Total $734,000
-------
27
In order to determine the most appropriate alternative that is
protective of human health and the environment, attains ARARs, is
cost-effective, and utilizes permanent solutions and treatment
technologies to the maximum extent practicable, alternatives were
evaluated against each other. Comparisons were based on the nine
evaluation criteria outlined in SARA. A summary of the
comparison is provided in Table 16. Following is a discussion of
each of the criteria and a summary of the alternatives'
performance against each of these.
1. Overall Protection of Human Health and the Environment:
Each of the alternatives (except No Action) will achieve
reduction of risks from contaminants and pathways of concern
; identified for the site. However, the alternatives differ in the
time needed to purge the aquifer of contaminants, and thus time
to reduce risks from drinking water, groundwater, and air
emissions. Alternative 1 requires the longest time to achieve
clean-up. Alternative 2 requires the next longest period.
Alternatives 3 and 4 require similar periods for remediation of
the east side contaminant plume which is expected to be shorter
than pump and treat under Alternative 2. However, as with
.Alternative 2, Alternatives 3 and 4 do not provide any reduction
in time for purging of the deep plume migrating under the River
to CW3. This results in a significantly long time period for
contaminants to remain in the aquifer. In addition, there is
some uncertainty as to whether in-situ bioreclamation would
perform as predicted for the contaminants present at the site.
Alternative 5 achieves source reduction which results in a
substantial reduction in time for remediation of contamination in
the aquifer. Increased pumpage of City supply wells as called
for under this alternative, further reduces the time for
remediation of the site.
2. Compliance with ARARs; All applicable or relevant and
appropriate requirements under Federal and State environmental
regulations are met by Alternatives 2, 3, 4 and 5. Alternative l
(No Action) would not comply with Wisconsin NR 140 requirements
for response when groundwater quality standards are exceeded.
Therefore, the No Action alternative will not be included in the
discussions that follow pertaining to evaluation of alternatives
against the remaining criteria.
Superfund monies may not be able to be used at the Wausau Energy
source area if it is determined that contaminants from this
source are strictly derived from a petroleum source. However,
the Wisconsin Hazardous Substances Spill Law does include a
provision to address such spills and would be pursued.
3. Long-term Effectiveness; The alternatives differ in the time
required to achieve various objectives, but in the long-term,
each of the action alternatives is expected to achieve compliance
-------
TABU 16
SUHHART OF ALTERNATIVES (VALUATION
FEAsieum STUDI
UAUSAU UAKR SUPPU NPL SITE
UAUSAU. WISCONSIN
Page I of 4
Evaluation
factor
Short-Term
Effectiveness
Alternative I
No Action
No additional protection of
community and workers is
required.
No additional risks beyond
baseline conditions.
Approximately 20 years of
purging norIhern portion of
west side flume by Well CU6.
long-Tern
Effectiveness
Can achieve NCLs and
contaminant levels
approaching state
groundwater standards in
aquifer.
Alternative 2
broundwater Extraction
and Treatment
Risks to Horkers during
implementation addressed by
standard controls and
personal protection
equipment. Community risks
considered to be minimal.
Stripping tower off gas
controls are provided to
control potential additional
exposure risks.
Approximately 20 years of
purging northern portion of
west side plume by well CU6.
Achieves protection through
contaminant removal and
above-ground treatment.
Alternative 3
Groundwater Extraction
and Treatment with
In-SItu Btoreclamation
Risks to workers during
implementation addressed by
standard controls and
personal protection
equipment. Community risks
considered to be minimal.
Stripping tower off-gas
controls are provided to
control potential additional
exposure risks. Possible
migration of contaminants
from recharge area is
controlled by extraction rate
greater than recharge rate.
Approximately 20 years of
purging northern portion of
west side plume by well CU6.
Achieves protection through
combination of contaminant
removal, above ground
treatment, and in-situ
groundwater treatment.
Can achieve NCLs and
contaminant levels
approaching stale groundwater
. standards in aquifer.
Groundwater extraction and
treatment technologies are
reliable. Repair or
replacement in relatively
short time is feasible, in
the event of failure.
Alternative 4
In-Sttu Horec tarnation
Risks to workers during
implementation addressed by
standard controls and personal
protection
equipment. Community risks
considered to be minimal.
Possible migration of contami-
nants from recharge area Is
anticipated. Quantity can be
limited by controlling the
blorectarnation system
recirculation rate.
Approximately 20 years of
purging northern portion of
west side plume by well CU6.
Achieves protection through In-
situ groundwater treatment.
Can achieve HCLs and
contaminant levels
approaching state groundwater
standards in aquifer.
Groundwater extraction, and
treatment technologies are
reliable. Infiltration
technology is reliable but
potentially subject to
footing, limitations can be
managed with sound operation
and maintenance strategies.
bioreclamation aspect 11
reliable if desired bacterial
populalions can be
maintained. In worst case
Idi lure mode, system can
operate as conventional pump
anil treat system.
Can achieve NCls and
contaminant levels approaching
state groundwater standards in
aquifer.
Groundwater extraction
technology is reliable.
Infiltration technology is
reliable but potentially
subject to fooling.
limitations can be managed with
sound operation and maintenance
strategies. Bioreclamation is
reliable if desired bacterial .
populations can be maintained.
Alternative S
Active
Source Control(l>
Risks to workers during
Implementation addressed by
standard controls and
personal protection
equipment. Community risks
considered to be minimal.
Vapor extraction system off-
gas controls are provided
to control potential
additional exposure risks.
Approximately 20 years of
pure Ing northern portion of
we*! side plume by well CU6.
Achieves protection
prlmarltbv preventing
additional contaminant
loading to .the aquifer as a
result of soil vapor
extraction.
Can achieve HCls and
contaminant levels
approaching state
groundwatesttndards In
aquifer.
Vapor extraction technology
Is reliable. Repair or
replacement In relatively
short time Is feasible In the
event of failure.
-------
IABIE 16
(Continued) .
SUItlARI OF ALTERNATIVES EVALUATION
FEASIBILITY STUDY
WAUSAU WAIF.R SUPPLY NPl SITE
UAUSAU. WISCONSIN
Page 2 of 4
Evaluation
Factor
Alternative I
Ho Action
long-term management
consist) of monitoring Hater
quality and aquifer purging
effectiveness by existing
wells.
Reduction of None
Ton(city. Nobility.
Volume
Implementablllty
Technical feasibility
considerations are not
applicable.
Coil
Hay not be administratively
feasible due to lack of
additional responses.
No additional services
required.
No direct monetary cost
Alternative 2
Groundtiater Infraction
and Treatment
long-term management consists
of Monitoring water levels,
water quality, discharge
quality and routine system
maintenance.
Voluae and toxicity reduction
through carbon adsorption and
thenul regeneration.
Groundnater extraction,
treatment and discharge
technologies are
conventional. System
effectiveness and performance
are readily monitored.
Coordination between U.S. EPA
and UDNR for plan review and
approval. Coordination with
local agencies may be
required. Coordination with
PRP representatives will be
required. No apparent
administrative difficulties.
Required technologies and
services are available.
Off-site services including
POtW and sanitary landfill
may be required, and are
considered to be available.
Capital: $480.000
Annual Olfl: H2?,000
Present yorlh: $l.))0.000
Discount Period; I? years
Disc mini Nate: IU\
Alternative 3
Groundwater Extraction
and Treatment with
In-Situ Bioreclamation
long-term management consists
of monitoring water levels,
water quality, discharge
quality and routine system
maintenance.
Toxic Ity reduction through
contaminant degradation.
Volume and loiIcIty'reduction
through carbon adsorption and
thermal regeneration.
Groundwaler extraction
treatment discharge and
Infiltration technologies are
all conventional Hydraulic
control of the area appears
feasible. Bioreclamation
appears feasible. Full site-
specific assessment will
require testing. System
effectiveness and performance
are readily monitored.
Coordination between U.S. EPA
and UONR for plan review and
approval. Coordination with
local agencies will be
required. Coordination with
PRP representatives will be
required. No apparent
administrative difficulties.
Required technologies and
services are available.
Off-site services including
POIW and sanitary landfill
may be reauired. and are
considered (o be available.
Capital: 1990,000
Annual Olh 1I6IDOO
Pitiful Worth: ll.710.000
Discount Period: 6 years
Discount Half: I0\ "'
Alternative 4
In-Sttu tloreclamatlon
long-term management consists
of monitoring water levels,
water quality, recharge water
quality and routine system
maintenance.
Toxtclty reduction through
contaminant degradation.
Groundwaler extraction and
technologies are conventional.
Complete recapture and
recharged water is not
feasible. Bioreclamation
appears feasible. Full
site-specific assessment will
reauire testing. System
effectiveness and performance
are readily monitored.
Coordination between U.S. EPA
and UONR for plan review and
approval. Coordination with
local agencies will be
required, coordination with
PRP representatives will be
required. No apparent
administrative difficulties.
Required technologies and
services are available.
Off-site services including
POTW and sanitary landfill may
be required, and are considered
to be available.
Capital: 1710.000
Annual OU1: $112.000
Present Worth:- $1.380.000
Discount Period: 9 years
Discount Rate: 101
Alternative S
Active
Source Control(II
Vapor extraction has a short
operation period. Long-term
management consists of
monitoring as In
Alternative 1.
Volume and toxlclty reduction
through carton adsorption and
thermal regeneration.
Vapor extraction technology
is conventional. System
effectiveness and performance
are readily monitored.
Coordination between U.S. EPA
and UONR for plan review and
approval. Coordination with
local agencies may be
required. Coordination with
PRP representatives will be
required. No apparent
administrative difficulties.
Required technologies and
services are available.
Off-site services Including .
POW and sanitary landfill
may be required, and are •
.considered to be available.
Capital: J2S6.000
OIN: $482.000
Present Worth: $7)6.000
Discount Period: 14 years
Discount Rate: 10% . .
-------
IABIC 16
(Continued)
SUHHAR* Of ALTERNATIVES EVALUATION
fEASIBILIU SIUDI
UAUSAU WATER SUPPU NPl SITE
MAUSAU. WISCONSIN
rage 1 01
Evaluation
factor
Compliance with
ARARs
Alternative 2
Groundwater Extraction
and Treatment
NCU achieved for Municipal ' HCl* achieved for Municipal
Mater itudy. water study.
Alternative I
Mo Action
likely would not comply with
NR 140 requirement for
response due to Itch of
source area control and no
additional groundwater
remediation.
HCls and State groundwater
standards could be achieved
in the aquifer in the long
ten.
Compliance with VOC
emissions limits can be
achieved.
Overall Protection
of Human Health and
the Environment
HCLs are met by VOC removal
dt City water treatment
plant.
No additional source or
groundwater controls.
Approximately ten years to
meet ICE HCl at well CW6.
Would likely comply with
NR 140 requirement for
response as a groundwater
control measure.
Alternative )
Groundwater Extraction
and Treatment with
In-Situ Bloreclamation
HCls achieved for municipal
water study.
Would likely Comply with
NR 140 requirement for
response as a groundwater
control measure.
HCls and State groundwater
standards could be achieved
in the aquifer in the long
term.
Compliance with VOC emissions
limits can be achieved.
Effluent standards can be met
for surface water discharge.
Compliance with action-
specific ARARs related to
design, approval,
construction and monitoring
can be met.
HCls are met by VOC removal
at City water treatment
plant.
Alternative 4
In-SItu Bioreclamatlon
HCls achieved for municipal
water study.
Would likely comply with NR 140
requirement for response as a
groundwater control measure.
HCls and State groundwater
standards could be achieved
in the aquifer In the long
term.
Compliance with VOC emissions
limits can be achieved.
Effluent standards can be met
for surface water discharge.
Compliance with action-
specific ARARs related to
design, approval,
construction and monitoring
can be met.
HCls are met by VOC removal
at City water treatment
plant.
HCLs and State groundwater
standards could be achieved In
the aquifer in the long term.
Compliance with VOC emissions
limits can be achieved.
Alternative S
Active
Source Controldt
HCls achieved for municipal
water study.
Would Ilkelv comply with
NR 140 requirement for
response as a source control
measure.
HCls and State groundwater
standard* could be achieved
in the aquifer In the long
term.
Compliance with VOX emissions
limits can be achieved.
Compliance with action-specific
ARARs related to design,
approval, construction and
monitoring can be met.
HCls are met by VOC removal at
City water treatment
plant.
Groundwater controls only. Groundwater controls only. Groundwater controls only.
Approximately ten ye<
meet TCE HCL at well
years to
ICE HCL at well CU6.
Approximately ten years to
meet TCE HCL at well CW6.
Approximately ten years to meet
TCE HCL at well CV6.
Compliance with action-
specific ARARs related to
design, approval,
construction and monitoring
can be met.
HCLs are met by VOC removal
at City water treatment
plant.
Source controls only.
Approximately ten years to
meet TCE HCl at well CW6.
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TABU 16
(Continued)
SUHHARV OF ALTERNATIVES EVALUATION
FEASIBILITY STUD*
UAUSAU UATER SUPPl» NPL SITE
UAUSAU. WISCONSIN
Page 4 of 4
Evaluation
factor
Alternative I
No Act ton
Alternative 2
Groundwater Eitfiction
and treatment
Approximately 20 ye«n until Xpproxlmately 20 years until
contMintnti «re no longer contaminants »re no longer
drawn in by well CU6. drum in by veil CU6.
Approximately 9.7 years to
•eel TCf MCI at Production
Well CU6.
Approximately 6 years to
Met TCE HCL it Hell CW3
(Und(i)l source).
Approximately 6.) years to
•eet PCE NCL at well CM]
(Uausau Chemical Source).
Approximately I) years until
contaminants from landfill
source are no longer drawn
in by well CUJ.
Approximately IS years until
contaminants from Uausau
Chemical are no longer drawn
In by well CU).
Would not comply with all
identified ARARs.
State and Community
Acceptance
Specific c
addressed in
Decision.
int* to be
the Record of
Approximately 9.7 years to
Met TCE HCL at Production
Uell C6.
Approximately 6 years to meet
TCE HCL at well CU3 (landfill
source).
Approximately S years to Met
PCE HCL at well CU3 (Uausau
Chemical Source).
Approximately 13 years until
contaminants from landfill
source are no longer drawn in
by well CUJ.
Approximately 12 until .
contaminants from Uausau
Chemical are no longer drawn
in by well CUJ.
Uould comply with all
identified ARARs.
Specific comments to be
addressed in the Record of
Decision.
Alternative 3
Groundwater Extraction
and Treatment with
In-Situ Bipreclamatlon
Approximately 20 years until
contaminants are no longer
drawn in by well CU6.
Approximately 9.7 years to
Met TCE HCL at Production
Uell CU6.
Approximately 6 years to meet
TCE HCL at well CUJ (landfill
source).
Approximately 2.S years to
Met PCE HCL at well CU3
(Uausau Chemical Source).
Approximately 13 years until
contaminants from landfill
source are no longer drawn In
by well CUJ.
Aquifer purging time could
not be estimated for this
alternative with the existing
contaminant transport model.
Uould comply with all
identified ARARs.
Specific comments to be
addressed in the Record of
Decision.
Alternative 4
In-Sttu Bioreclamatlon
ApproiiMtely 20 yean until
contaminants are no longer
drawn In by well CU6.
Approximately 9.7 years to Met
TCE HCL at Production Hell CU6.
Approximately 6 years to Met
TCE HCL at well CU) (landfill
source). . :
'ears to I
lauttu
eet
Approximately 2.S yean
PCE HCL at well CUJ (U,
Chemical Source).
Approximately 13 years until
contaminants from landfill
source are no longer drawn In
by well CU3.
Aquifer purging HM could not
be estimated for the
alternative with the existing
contaminant transport model.
Uould comply with all
identified ARARs.
Specific comments to be
addressed in the Record of
Decision.
Alternative 5
Active
Source ControUl)
Approximately 14 yean
unttlcontaminants are no
longer drawn In by well CU6.
Approximately 4.S years to
Met TCE HCL at Production
Well CU6.
Approximately 4 years to
MCTCE HCL at well CU3
(landfIt source).
Approximately 3.) yean to
Met PCE HCL at Mil CUJ
(Uausau Chemical Source).
Approximately C year* until
contaminants from landfill
source art no longer drawn
in by well 013.
Approximately 5 years until
contaminants fro* Uausau
Chemical are no longer drawn
in by well CU3.
Uould comply with all
identified ARARs.
Specific comments to be
addressed in the Record of
Decision.
(I) Remediation lines shown for Alternative S are based on computer simulations of source control used in conjunction with increased pumping rates at Production Uells CU3
and CU6. and at the Phase 1 reMdy nlraction well.
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28
with MCLs and State groundwater standards (NR 140) in the
aquifer. Table 16 lists the time period requirement for each of
the alternatives.
4. Reduction of Toxicity. Mobility or Volume; Alternatives 3
and 4 provide toxicity reduction as a result of contaminant
degradation. Volume and toxicity reductions are provided by
Alternatives 2, 3 and 5 as a result of contaminant adsorption on.
vapor phase carbon and subsequent destruction during thermal
regeneration of the carbon.
5. Short-Term Effectiveness; The short-term risks associated
with implementation are not expected to be a problem for any of
the alternatives. All of the alternatives (including the Phase I
Remedy) will result in contaminated material being brought to
the surface, however no appreciable risks to residents are
expected, and workers can use conventional personnel protective
gear.
Short-term risks associated with operation of the alternatives
vary. Carbon treatment of off-gases generated by stripping of
VOCs is planned for Alternatives 2,5, and the pump and treat
portion of Alternative 3. Alternative 4 and the bioreclamation
portion of alternative 3 do have potential risks associated with
the additives necessary for contaminant breakdown and the
transformation products from the process. Risks from these
alternatives would result if the contaminants were not broken
down completely before reaching CW3, or if additives from the
process were to reach CW3.
The alternatives differ in the time needed to purge the aquifer
of contaminants. Alternative 2 requires the longest time to
achieve aquifer purging. This is because pumping of extraction
wells at Wausau Chemical in conjunction with CW3 would create a
groundwater divide that would actually cause contaminants to be
held up longer in the aquifer. In addition, this alternative
would not reduce the time frame during which contaminants would
continue to impact CW6 on the west side of the River.
Alternatives 3 and 4 require similar periods for remediation of
the east side contaminant plume which is expected to be shorter
than pump and treat under Alternative 2. However, as with
Alternative^, these alternatives do not provide any reduction in
time for purging of the deep TCE plume migrating under the River
to CW3. Alternative 5 results in a substantial reduction in time
for remediation of contamination in the aquifer because it
addresses the source areas on both sides of the River. Added
controls on pumping rates of City supply wells further reduces
the time for remediation under this alternative.
6. Implementability; Technologies used for Alternatives 2 and
5, and part of 3, are conventional and well demonstrated.
Bioreclamation as proposed for Alternative 4 and part of
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29
Alternative 3 is not conventional or well demonstrated for the
types of chemicals found at the site. In addition, U.S. EPA's
Office of Research and Development (ORD) has reviewed the
potential for In-situ Bioreclamation and has expressed concern
over the uncertainties regarding whether this technology would
work for the contaminants found at the site. Implementation
would require fairly extensive laboratory and field testing prior
to start-up. It is estimated that approximately two years would
be required prior to full scale operation of a bioreclamation
system at the site.
Administratively, Alternative 5 would require the least amount of
coordination. Alternatives 2, and the above ground portion of 3
require additional coordination because of treatment and
discharge system. Alternative 4 and the in-situ portion of 3
would be administratively difficult because the technology is
relatively unknown, and requires reinjection of water back into
the ground.
There are no difficulties anticipated in obtaining materials for
any of the alternatives. Materials/are available and considered
conventional and readily available.
7. Cost; Comparison of present worth costs for the alternatives
indicates that Alternative 5 is the least costly at $738,000.
This is due to the shorter operation time of the source control
action and the reduced O&M costs associated with the City air
strippers due to the reduced time required for their use.
Alternative 2 has the next lowest present worth cost at
$1,330,000. Alternative 4 is somewhat higher at $1,380,000 and
the present worth cost for Alternative 3 is highest at
$1,710,000 due to the combination of systems used. Alternative 1
has no associated costs.
8. State Acceptance; The State had expressed interest in a
bioreclamation alternative if one showed promise for the site.
However, because of the need for extensive laboratory and field
pilot studies, the .State has agreed that a bioreclamation
alternative should not be pursued for the site. The State
supports Alternative 5 due to its ability to reduce aquifer purge
times at a low cost.
9. Community Acceptance; The City of Wausau, Marathon Electric,
and Wausau Chemical, all of which are PRPs, have expressed a
preference for Alternative five. The community in Wausau has not
expressed a preference for any alternative. Specific comments
received during the public comment period and at the public
meeting for the proposed plan are addressed in the responsiveness
summary included with this document.
SUMMARY OF COMPARISON
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30
Under Alternative 1 (no action), contaminants would be purged
only through pumping of the supply wells and the west side
extraction well. Nothing would be done to reduce contaminant
loading to the aquifer from source areas nor to expedite removal
of contaminants in the East Well Field. Given the nature and
location of the site, this alternative is not consistent with the
objectives for remedial action at the site and is therefore not
considered a viable option for the site. In addition, Wisconsin
groundwater standards under NR 140 would not be met under this
alternative. NR 140 has been determined to be an ARAR for the
site. /.. •'.',•.•.•••:- ' •..-.'; •. - . -' ; . - -
Although all of the other alternatives will achieve aquifer '
purging in the long-term, there are significant differences in
the time to purge the groundwater. Alternatives 2, 3, and 4 are
groundwater remediation alternatives that do not address
remediation of source areas, in addition, they do not provide
any reduction in the timeto.remediate the deep plume originating
from the landfill. This results in a significant time period to
achieve the response objectives. In addition, the actual time
frame for aquifer purging under the bioremediation alternatives
cannot be determined, so an estimate is based on groundwater
flow. Alternative 5, source control, requires the shortest time
period for remediation of the site because it eliminates the
continued addition of contaminants to the groundwater and
provides for the removal of remaining contaminants in groundwater
through pumping of CW3 and CW6. Alternative 5 also provides for
a reduction in time to purge the deep west side plume by
removing the source and specifying pumping rates for the city's
supply wells CW3 and CW6.
All of the alternatives (other than No Action) provide a
reduction in toxicity of contaminants. Alternatives 2, 5 and the
pump and treat portion of 3 provide a reduction in volume as
well. Alternatives 2 and 5 use proven technologies that can
easily be implemented and have a low potential for failure/ and
the proposed actions will have no problem complying with Federal
and State ARARs. Alternatives 3 and 4 use a technology that may
not be completely effective on the contaminants present at the
site. In addition, some of the required additives needed to
enhance biodegradation, could exceed the State's NR 140
groundwater standards for those substances.
Costs and implementation times for alternatives vary as well.
Alternative 5, source control, is the least costly and requires
the shortest time period to implement and complete the remedial
action. Alternative 2 has the next lowest cost and requires a
similar implementation period. Alternatives 3 and 4 have the
highest costs associated with them due to the bioreclamation
technology proposed. These alternatives also require the
longest implementation time. A period of 2 years to begin the
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31
process will be required due to the need for extensive testing
prior to start up.
IX. SELECTED REMEDY AND STATUTORY DETERMINATIONS
Section 121 of SARA required that all remedies for Superfund
sites be protective of human health and the environment, comply
with ARARs, be cost-effective, and utilize permanent solutions
and alternate treatment technologies to the maximum extent
practicable. Alternative 5 is believed to provide the best
balance of trade-offs among alternatives with respect to the
criteria used to evaluate remedies. Based on the evaluation of
the alternatives, U.S. EPA and the State of Wisconsin believe
that Alternative 5 would be protective, attain ARARs, be cost-
effective, and will utilize permanent solutions and alternate
treatment technologies or resource recovery technologies to the
maximum extent practicable.
The selected remedy entails:
- Installation of soil vapor extraction (SVE) systems to
remove VOCs in soils at each of the three identified source
• areas; '• •''•'. • •.'•..'••..;.' '. . •".
- Treatment of off-gases from the SVE operation using vapor
phase carbon units which will be regenerated at an off-site
RCRA approved facility; and
- Groundwater remediation utilizing specified pumpage rates of
the municipal supply wells in order to expedite removal of
the groundwater contaminant plumes affecting these wells.
- Treatment of groundwater utilizing existing City air
strippers
The response objectives for the final remedy are to eliminate
risks to groundwater by reducing the source of contaminants in
source areas' soils, and to minimize VOC emissions to air from
the existing and proposed treatment processes. The performance
standards for the SVE in source soils will be determined using a
mass-flux groundwater model to determine what cleanup levels are
needed in soils to achieve cleanup of the aquifer. These cleanup
levels will be based on the requirement to attain Wisconsin KK
140 groundwater standards for PCE, 1.0 ug/1, and TCE, 1.8 ug/1 at
the source boundary. Attainment of cleanup levels will be
confirmed through sample analysis of groundwater at the boundary
of the source areas.
The final remedy incorporates the interim remedy such that the
west side extraction system is considered part of the overall
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32
site remediation. It is expected to address the TCE
contamination originating from the former City landfill/Marathon
Electric source area which migrates to both CW6 and CW3. It also
includes a provision for an additional extraction well if
required to obtain the desired performance objectives. The
interim ROD did not specify a time period for operation of the
west side extraction system because contaminant transport
modeling had not been completed at the time. It is now
anticipated that this system will be required to operate for
approximately 14 years; until levels of TCE are not detected
above the Wisconsin NR 140 Standard of 1.8 ug/1 at specified
points of compliance.
The costs estimated for Alternative 5 do riot include costs for
operating the interim remedy extraction well. Five years of
operation and maintenance costs for the interim remedy were
estimated in the Interim ROD. It is now estimated that the
system will be required to operate for approximately 14 years.
This will require an additional 9 years of 0 & M and will result
in additional costs for that system. Estimated costs for 0 & M'
of the interim system were estimated to be $140,000 per year.
However it is expected that actual O & M costs for the system
will be somewhat less due to overlap of monitoring requirements
for the remaining portions of the site.
The final remedy also will require that existing groundwater
extraction systems currently operating in the East Well Field,
other than City supply well CW3, cease operation once the SVE
system is installed. This is necessary in order to obtain the
desired result of purging contaminants from the aquifer utilizing
CW3. Groundwater modeling performed during the FS indicated that
competing extraction systems could cause contaminants to get
trapped at the groundwater divide created by multiple pumping
systems, and require longer purge time to remediate the aquifer.
As stated above, the remedy is considered the most cost-effective
remedial action. It complies with Federal and State ARARs. It
is protective of human health and the environment by reducing the
time period during which water consumers are exposed to trace
levels of contaminants in drinking water, by eliminating future
potential risk to private well users, and by preventing increased
VOC emissions to be released to the atmosphere. Requirements of
Section 121(b)(1)(A-G) which have been determined to be
applicable to this operation are discussed below.
1. Protection of Human Health and the Environment
Based on the risk assessment developed for the site, long-term
exposure to low levels of VOCs in drinking water, potential
exposure through the use of private wells, and exposure to air
emissions from existing VOC treatment systems are the identified
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33
risks associated with the site. Implementation of SVE systems at
the source areas and treatment of off-gases, as called for under
Alternative 5, provides protection to human health and the
environment through volatilization of VOCs from contaminated
soils, and expedited removal of contaminants from groundwater by
increased pumpage of municipal veils.
Volatilization of VOC-contaminated soils will eliminate the
source of continued loading of VOCs to the aquifer; thus reducing
the time during which residents are exposed to trace levels of
VOCs. Implementation of Alternative 5 will not pose any
unacceptable short-term risks or .cross-media impacts to the site,
the workers, or the community. No environmental impacts have
been identified for the site. This is largely due to the fact
that impacts from the site have be'en to groundwater, and soils in
industrial areas.
2. Attainment of Applicable or Relevant and Appropriate
.Requirements of Environmental Laws
..•''•• ..' • • • ..'.''•.-.- • ' >
Alternative 5 will be designed to meet all applicable or relevant
and appropriate requirements (ARARs) of Federal and more
stringent State environmental laws* Tables 7-11 list the ARARs
that apply to each of the action alternatives and the following
discussion provides the details of the ARARs that will be met by
Alternative 5. The Land Ban requirements of RCRA do not apply to
this remedial action.
a. Federal; Safe Drinking Water Act fSDWAl / State;
Chapter NR 109 Wisconsin Administrative Code (WAC)
The SOWA and corresponding State standards specifies maximum
contaminant levels (MCLs) for drinking water at public water
supplies. Since TCE is regulated under the SDWA MCLs,
requirements for achieving MCLs are relevant and appropriate for
this remedial action. PCE is under consideration for a proposed
MCL of 5 ug/1 in the near future. Therefore, the likely proposed
MCL for PCE is a TBC (to be considered) for this remedial action.
b. State; Chapter NR 140 WAC
Wisconsin groundwater protection Administrative Rule, Chapter NR
140 WAC, regulates public health groundwater quality standards
for the State of Wisconsin. The enforceable groundwater quality
standard for TCE is 1.8 ug/L. Groundwater quality standards as
found in NR 140 WAC are ARARs for this remedial action.
c. Federal; Clean air act fCAAl
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34
The CAA identifies and regulates the release of pollutants to
air. Section 109 of the CAA identifies those pollutants for
which Ambient Air Quality Standards (AAQS) have been established.
Section 112 outlines criteria for pollutants for which there are
no applicable AAQS. Emissions from existing and proposed
treatment systems are not expected to exceed the AAQSs for any of
the compounds present in groundwater.
d. State; Chapter NR 445 WAG
Wisconsin Chapter NR 445 establishes hourly or annual emission
rate limits for specific contaminants. Emissions rates on the
order of 1 lb/day for individual systems are estimated and would
be expected to meet the limits.
3. Cost-effectiveness
Alternative 5 affords a high degree of effectiveness by providing
protection from chronic low level exposure of TCE for production
wells CW3 and CW6, providing protection from potential exposure
to future private well users, and preventing further discharge of
VOC emissions. Alternative 5 is the least costly alternative
that is protective of human health and the environment.
Therefore, Alternative 5 is considered to be the most cost-
effective alternative that- is protective.
4. Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum
Extent Practicable
U.S. EPA and the State of Wisconsin believe the selected remedy
represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective
manner for the final remedy at the Wausau site. Of the
alternatives that are protective of human health and the
environment and comply with ARARs, U.S. EPA and the State have
determined that the selected remedy provides the best balance of
tradeoffs in terms of long-term effectiveness and permanence,
reduction in toxicity, mobility or volume achieved through
treatment, short-term effectiveness, implementability, cost, also
considering the statutory preference for treatment as a principal
element and considering State and community acceptance.
Although all of the alternatives that are protective and comply
with ARARs will achieve reduction of risks, there are significant
differences in the time required to achieve this goal.
Alternatives 2, 3, and 4 are groundwater remediation alternatives
that do not address source areas. This results in contamination
from source area soils loading to the .aquifer for several
additional years. In addition, none of these alternatives
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35
provide any reduction in time to remediate the deep TCE plumes
originating from the former landfill source area. This also
results in a significant time period to achieve reduction of
risks. Alternative 5 requires the shortest time period for
remediation of the site because it eliminates the continued
loading of contaminants to the groundwater, and it provides for
reduction in time to purge the deep TCE plumes by removing the
source and increasing removal rates of contaminants at the
Municipal supply wells.
The selection of a treatment technology for remediation of
contaminated soils is consistent with the Superfund program
policy that the highly toxic and mobile wastes are a priority for
treatment and to ensure permanence and long-term effectiveness of
the remedy. Under the selected remedy, treatment of groundwater
will not provide a reduction of toxicity, mobility, or volume
(TMV). However, it will reduce contaminant levels in groundwater
and thus reduce the risks associated with ingestion of
groundwater, which has been determined to be a greater risk
than inhalation of air emissions. While other alternatives v
evaluated provided treatment to achieve TMV reductions in
groundwater, these alternatives had other difficulties.
Alternative 2 required almost twice as long to purge
contaminants. Alternatives 3•and 4 propose a technology that has
not been shown to work on contaminants present in groundwater at
the site and thus would require extensive testing that would
delay full scale operation of the system for an estimated two
years. Based on these factors, it was determined that
Alternative 5 would provide the shortest time period during
which receptors would be exposed to contaminants in drinking
water. In addition, based on air modeling, release of emissions
from the municipal air strippers do not contribute a greater than
1 x 10~6 risk level to receptors.
Since treatment of groundwater will not achieve a reduction in
toxicity, mobility or volume, the major trade-offs that provide
the basis for this selection decision are long-term
effectiveness, short-term effectiveness, implementability, and
cost. The selected remedy can be implemented and completed more
quickly with less difficulty and at less cost than groundwater
treatment alternatives, thus reducing the exposure time for
pathways of concern. Alternative 5 is therefore considered to be
the most appropriate solution to contamination at the site
because it provides the best trade-offs with respect to the nine
criteria and represents the maximum extent to which permanent
solutions and treatment are practicable.
5. Preference for Treatment as a Principal Element
By treating the VOC-contaminated soils using SVE with carbon
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36
absorption of off-gases with regeneration of the carbon, the
selected remedy satisfies the statutory preference for remedies
that employ treatment of the principal threat which permanently
and significantly reduces toxicity, mobility, or volume of
hazardous substances as a principal element. Treatment of
groundvater to reduce toxicity, mobility, or volume would also
seem to be desirable to satisfy the statutory preference.
However, treatment of groundwater to permanently and
significantly reduce toxicity, mobility, or volume of
contaminants was not found to be practicable or cost-effective
for remediation of the site.
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RESPONSIVENESS SUMMARY: WAUSAU GROUNDWATER CONTAMINATION SITE
WAUSAU, WISCONSIN
PURPOSE
This responsiveness summary is developed to document community
involvement and concerns during the development of the
feasibility study (FS) for the Wausau Groundvater Contamination
site, Wausau, Wisconsin. Comments received during the public
comment period were considered in the selection of the remedial
action for the site. The responsiveness summary serves two
purposes: It provides U.S. EPA with information about community
preferences and concerns regarding the remedial alternatives, and
it shows members of the community how their comments were
incorporated into the decision-making process.
This document summaries the oral comments received at the public
meeting held August 22, 1989, and one written comment received
during the public comment period of August 14 to September 12,\
1989.
OVERVIEW
The preferred alternative for the Wausau Groundwater
Contamination (Wausau) site was announced to the public just
prior to the beginning of the public comment period. The
preferred alternative includes:
- Installation of soil vapor extraction (SVE) systems to
remove VOCs in soils at each of the three,identified source
areas;
- Treatment of off-gases from the SVE operation using vapor
phase carbon units which will be regenerated at an off-site
RCRA approved facility; and
- Groundwater remediation utilizing specified pumpage rates of
the municipal supply wells in order to expedite removal of
the groundwater contaminant plumes affecting these wells.
- Treatment of groundwater utilizing existing City air
strippers
Judging from the comments received during the public comment
period, all parties support the selected remedy. However,
concern has been expressed over the amount of money spent to date
at the site by all parties involved.
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SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES
The public comment period was held from August 14 to September
12, 1989 to receive comments concerning the draft feasibility
study (FS) . Because of the similarities, individual comments
have been summarized and grouped where appropriate.
A. Comment • The Mayor of Wausau, the Wausau City Council
President, Wausau Chemical Corporation, and Marathon Electric
Corporation all expressed support for the Agency's selected
alternative. However, all parties also expressed concern over
the amount of money that has been spent on the site to date.
Specifically, for the Remedial Investigation/Feasibility study
(RI/FS) conducted by U.S. EPA's contractor, and the expenses
incurred by each of the involved parties for actions relating to
the contamination problem.
A. Response; U.S. EPA wishes to extend thanks to all parties for
their support of its selected remedial alternative for the site.
It is hoped that an expedited agreement can be reached and the
remedial action implemented in a timely manner. While U.S. EPA
understands the concern over costs that have been spent to date/
it also recognizes that the incurred costs could not have been
avoided. Studies of the nature required to fully identify the
extent of contamination at the site tend to be quite expensive.
The cost of the RI/FS for this site is within the average range
for an RI/FS. The costs incurred by individual parties related
to the contamination have, for the most part, been necessary to
address the more immediate problems posed by the contamination of
the City's well field.
B. CoTW^n^t Wausau Chemical Corporation has' requested specific
direction from U.S. EPA and WDNR be included in the ROD as to the
future operation of its groundwater extraction system in light of
the fact that the selected alternative does not include the
continued pumpage of groundwater in the vicinity of the Wausau
Chemical property.
B. Response ; The selected remedy calls for the removal of all
groundwater extraction systems, other than City Well 3, from the
East Well Field. This will include the Wausau Chemical
extraction system. This subject is also addressed in Section IX-
The Selected Remedy, of the ROD and is quoted below:
The final remedy also will require that existing groundwater
extraction systems currently operating in the East Well
Field, other than City supply well CW3, cease operation once
the SVE system is installed. This is necessary in order to
obtain the desired result of purging contaminants from the
aquifer utilizing CW3. Groundwater modeling performed
during the . FS indicated that competing extraction systems
could cause contaminants to get trapped at the groundwater
divide created by multiple pumping systems, and require
-longer purge time to remediate the aquifer.
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:SOLID UflSTE TO'- 9505395 SEP 29, 1989 8:39flM P.07
State Of Wisconsin \ DEPARTMENT OF NATURAL RESOURCES
Btttdny,
Box 7921
-' . _ Marfton, WTteont/n 53707
TELEFAX NO. C08-267-3579
TOO HO. tOO-267-eBi7
September 28, 1989 IN REPLY REFER TO: 4440
Mr. Valdus Adamkus, Regional Administrator
U.S. Environmental Protection Agency, Region V .
230 South Dearborn Street
Chicago, IL 60604
SUBJECT: Selected Superfund Remedy
Wausau Groundwater Contamination Site
Wausau, Wisconsin
Dear Mr. Adamkus:
Your staff has requested this letter to document our position on the final
remedy for the Wausau Groundwater Contamination Site. The proposed final
remedy, identified as Alternative No. S, is discussed fully in the Record of
Decision and includes:
* Installation of Soil Vapor Extraction (SVE) systems to remove volatile
organic compounds (VOCs) in soils at each of the three identified source
'•;•"' 'areas- .-. :
• Treatment of off•gases from the SVE operation using vapor phase carbon
units which will be regenerated at a off-site RCSA-approved facility; and
• Groundwater remediation utilizing specified pumpage rates of the
municipal supply wells in order to expedite removal of the groundwater
contaminant plumes affecting these wells.
The costs of the selected remedy are estimated to be
• Capital costs - $252,000
• Operation costs • $222,000
An eighteen month operating period was assumed and the costs were not
discounted.
Based upon our review of the public comment Feasibility Study received on
August 14, 1989, and the draft Record of Decision received on
September 8, 1989, our agency concurs with the selection of this remedy.
We understand that your staff and contractors, or the potentially responsible
parties will develop the major design elements of the soil vapor extraction
systems, the off»gas treatment system and the groundwater remediation system
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:SOLID UWSTE TQ:. 9505395 .. SEP 29, 1989 B''4Qf*\ p.
Mr. Valdus Adamkus - September 28, 1989 j> .
in close consultation with my staff during the predesign and design phases of
the project. We also . ^understand that if the potentially responsible parties
do not agree to fund the remedy, the State of Wisconsin will contribute 10% of
the remedial action costs. In addition to cost sharing on the remedy we
acknowledge our responsibility for operation and maintenance of this system
once the remedy is constructed. ;
As always, -thank you for your support and cooperation in addressing the
contamination problem ae this site. If you have any questions regarding this
natter, please contact Kr. .Paul Didier, Director of the Bureau of Solid &
Hazardous Waste Management Jaf (608) 266-1327.
Sincerely,
C. D. pesadny
Secretary
CDB:SB:ab33
d: \8910\sv9vsclt . sxb
cc: Lyman Wible - AD/5
Paul Didier - SW/3
Mark Ciesfeldt • SW/3
Gary Kulibert - NCD
Rene Sanf ord • FN/1
Horm Niedergang - EPA Region V
Margaret Cuerriero - EPA Region V
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