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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Page la.
&J/22/89
ucss/rms PIGSS sm     Tint
                          advises the USEPl,thit
                          they it intends to
                          negotiite a-resolution
                          ot its 'purported'
                          responsibility in
                          connection mi tht
                          site.

                          Idditioaal MM tor  the
                          site's IPL Site
                          tlternitites.

                          Contents  on the Iqencj
                          Reriev Suit  SI.
                                                    mmsmrivs :
                                                                  S,  VISCOUS!*
Hichtllt
OeBrock-Oveas-vm
Xichelle
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                                                                                                                             urns-.
            23S  55/07/31 tnlaatioa ot 3io-
                         reiediition ot Ground
                         facer it the Yausau ntt
                         ilonq vith reports is
                         tentioned in the
                         enlattion.
Dick Scilt-HSiPA  lerr    .UtrgirekGuerriero-HSSPlt  Correspondence-
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                 W/0&/Q1 Cotients on the  igencj
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                         ftisibilitj Study.
              4  iS/QS/OC  'Viaim fell  feisibilitj
                          Stadj. '

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                         Xetorandui
              1  Si/12/16 Kir lequlitions concerning
                         tht proposed Stripping
                         twer in the Vausau  JfPL
                         Sitt Phased feasibility
                         Study.

              1  M/tS/lt Couent on the lltermtires
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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
            I I
      wAUSAU CHEMICAL
                          STORAGE BUILDING
                           J10JND
                                 IIIIIIK IIKIIM
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                                          «
                                                                           CAST j;,«W». JI
                                                                                   '
       SIGN COMPANY
                                             FORMER
                                             CITY
                                             LANDFILL -
      PCE SPILL
      LOCATIONS
ILTRhTION PLANT
                                                                    SCHOFIELD PARK
                                                    AKE WAUSAU OdAMTE
                                              HURO
                                              TEST
                                              WELL
                                       -STEEL FLIHT SCAFFOLDING
                                                                                             lOUIIOI • IMICIMl Mill I
                                                                                             IKMIIIM ta
                                                                                                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.

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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

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                                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

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                                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

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                                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)

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                                                       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

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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

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                                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

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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.

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                                  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

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                                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

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                                                                                   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.

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                                                                                   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% .      .

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                                                                                   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.

-------
                                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

-------
                                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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