REMEDIATION SYSTEM EVALUATION
OCONOMOWOC ELECTROPLATING SUPERFUND SITE
ASHIPPUN, WISCONSIN
Report of the Remediation System Evaluation,
Site Visit Conducted at the Oconomowoc Site
14-15 March, 2000
Final Report Submitted To Region 5
August, 2000
(Reformatted, January 24, 2001)
sr,
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NOTICE
Work described herein was performed by GeoTrans, Inc. (GeoTrans) and the United States Army Corps
of Engineers (USAGE) for the U.S. Environmental Protection Agency (U.S. EPA). Work conducted by
GeoTrans, including preparation of this report, was performed under Dynamac Contract No. 68-C-99-
256, Subcontract No. 91517. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
This document (EPA 542-R-02-008b) may be downloaded from EPA's Technology Innovation Office
website at www.epa.gov/tio or www.cluin.org/rse.
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11
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EXECUTIVE SUMMARY
The 10.5 acre Oconomowoc Electroplating Company, Inc. located in Ashippun, Wisconsin,
encompasses a four-acre electroplating site adjacent to a six and one half-acre wetland. The
electroplating facility included a main process building, a wastewater treatment building, wastewater
treatment lagoons, and other miscellaneous storage areas. Drinking water wells are in the vicinity of
the facility in addition to the wetland area. Davy Creek, a small warm water sport fishery, flows
through the wetland area approximately 500 feet south of the site. Untreated wastes containing
volatile organic compounds, and heavy metals from degreasing, plating and finishing operations were
discharged directly to the Davy Creek Wetlands from 1957 to 1972. From 1972 until the site ceased
operations in the!980's waste was discharged to two waste lagoons. Metals contaminated hazardous
wastes and VOC's were found at numerous site locations including the lagoons, storage areas, in and
beneath the plating and water treatment buildings.
The remedy identified in the ROD included multiple removal activities to eliminate the source of
contamination from the site. These included:
excavation and disposal of the lagoon sludge and surrounding soils
excavation and disposal of non-lagoon contaminated soil and debris from the site
excavation and disposal of metals contaminated sediments from the wetlands area
adjacent to Davy Creek.
A groundwater extraction and treatment facility was built to contain and remediate the contaminated
groundwater plume. The EPA RPM indicated the extraction system and treatment plant has operated
successfully the last two years following some initial start up problems.
The source removal activities were successfully accomplished during the early to mid 1990's.
Subsequent to these removal actions, the metals concentrations in the groundwater extraction system
influent to the treatment plant are now present below the current preventive action limits (PALs) for
all constituents with the exception of nickel (which was not a listed COC in the 1990 ROD).
The RSE suggests many potential modifications to the existing pump-and-treat system at this site.
Several key recommendations address effectiveness issues:
a capture zone analysis is strongly recommended to evaluate the adequacy of the
capture zone of the pumping wells, and better understand impacts to the capture zone
due to contribution of water from the adjacent wetlands; and
additional delineation of groundwater contamination west of Eva Street, in a
residential area with drinking water wells, is strongly recommended.
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Other key recommendations address life-cycle cost reductions:
• potential removal of the cyanide treatment process (potential chemical savings over
the operating life-cycle of over $600,000);
• potential removal of the metals precipitation process (potential sludge disposal
savings over the operating life-cycle of over $500,000); and
• removal of these two processes would save approximately $117,000 in annual labor
costs due to reduced staffing requirements at the treatment plant (savings over the
operating life-cycle of over $2,300,000).
Replacement of the current remedial technology, pump and treat, with a permeable reaction wall
would result in a capital cost of approximately $1.5 million, but could result in a life-cycle cost
savings of nearly $7 million.
More than ten other modifications are recommended to improve technical aspects of the existing
pump-and-treat system, and additional recommendations are made to improve the potential for
ultimate site closeout.
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PREFACE
This report was prepared within the context of a demonstration project conducted by the United
States Environmental Protection Agency's (USEPA) Technology Innovation Office (TIO). The
objective of the overall project is to demonstrate the application of optimization techniques to Pump-
and-Treat (P&T) systems at Superfund sites that are "Fund-lead" (i.e., financed by USEPA). The
demonstration project was conducted in USEPA Regions 4 and 5.
The demonstration project has been carried out as a cooperative effort by the following
organizations:
Organization
Key Contact
Contact Information
USEPA Technology Innovation
Office
(USEPA TIO)
Kathy Yager
2890 Woodbridge Ave. Bldg. 18
Edison, NJ 08837
(732)321-6738
Fax: (732) 321-4484
yager.kathleen@epa.gov
GeoTrans, Inc.
(Contractor to USEPA TIO)
Rob Greenwald
GeoTrans, Inc.
2 Paragon Way
Freehold, NJ 07728
(732) 409-0344
Fax: (732) 409-3020
rgreenwald@geotransinc. com
Army Corp of Engineers:
Hazardous, Toxic, and Radioactive
Waste Center of Expertise
(USAGE HTRW CX)
Dave Becker
12565 W. Center Road
Omaha, NE 68144-3869
(402) 697-2655
Fax: (402) 691-2673
dave.j .becker@nwd02.usace.army.
mil
The project team is grateful for the help provided by an EPA Project Liaison in each Region. Kay
Wischkaemper in Region 4 and Dion Novak in Region 5 were vital to the successful interaction
between the project team and the Regional Project Managers (RPM's) during the course of this
project, and both actively participated in one Remediation System Evaluation (RSE) site visit
conducted in their Region.
The data collection phase of this project included interviews with many RPM's in EPA Regions 4
and 5. The project could not have been successfully performed without the participation of these
individuals.
Finally, for the sites where RSE's were preformed, additional participation and substantial support
was provided by the RPM's (Ken Mallary and Ralph Howard in Region 4; Steve Padovani and
Darryl Owens in Region 5), and their efforts are very much appreciated, as are the efforts of the State
regulators and EPA contractors who also participated in the RSE site visits.
in
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TABLE OF CONTENTS
EXECUTIVE SUMMARY i
PREFACE iii
TABLE OF CONTENTS iv
1.0 INTRODUCTION 1
1.1 PURPOSE 1
1.2 TEAM COMPOSITION 1
1.3 DOCUMENTS REVIEWED 2
1.4 PERSONS CONTACTED 2
1.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS 2
1.5.1 LOCATION 2
1.5.2 POTENTIAL SOURCES 3
1.5.3 HYDROGEOLOGIC SETTING 3
1.5.4 DESCRIPTION OF GROUND WATER PLUME 3
2.0 SYSTEM DESCRIPTION 4
2.1 SYSTEM OVERVIEW 4
2.2 EXTRACTION SYSTEM 4
2.3 TREATMENT SYSTEM 5
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE CRITERIA 6
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 6
3.2 TREATMENT PLANT OPERATION GOALS 6
3.3 ACTION LEVELS 6
4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT 8
4.1 FINDINGS 8
4.2 SUBSURFACE PERFORMANCE AND RESPONSE 8
4.2.1 WATERLEVELS 8
4.2.2 CAPTURE ZONES 8
4.2.3 CONTAMINANT LEVELS 9
4.3 COMPONENT PERFORMANCE 10
4.3.1 TREATMENT SYSTEM PERFORMANCE (I.E., DOWN-TIME) 10
4.3.2 WELLS 10
4.3.3 CARBON UNITS 10
4.3.4 ALKALINE OXIDATION CYANIDE REMOVAL SYSTEM 10
4.3.5 METALS PRECIPITATION SYSTEM 11
4.3.6 NEUTRALIZATION 11
4.3.7 TERTIARY FILTRATION 11
4.3.8 AIR STRIPPERS 12
4.3.9 PIPING 12
4.3.10 CHEMICALFEED SYSTEMS 12
4.3.11 SLUDGE HANDLING AND TREATMENT 12
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF COSTS 13
4.4.1 UTILITIES 13
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS 13
4.4.3 LABOR 13
iv
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4.4.4 CHEMICAL ANALYSIS 13
4.4.5 OTHER COSTS 14
4.5 RECURRING PROBLEMS ORISSUES 14
4.5.1 CYANIDE SYSTEM CLEANING 14
4.5.2 SUMP OVERFLOW 14
4.6 REGULATORY COMPLIANCE 14
4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL CONTAMINANT/REAGENT
RELEASES 15
4.8 SAFETY RECORD 15
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT
16
5.1 GROUND WATER 16
5.2 SURFACE WATER 16
5.3 AIR 16
5.4 SOILS 16
5.5 WETLANDS 17
6.0 RECOMMENDATIONS 18
6.1 RECOMMENDED STUDIES TO ENSURE EFFECTIVENESS 18
6.1.1 CAPTURE ZONE ANALYSIS 18
6.1.2 PLUME DELINEATION WEST OF EVA STREET 18
6.1.3 SURFACE WATER SAMPLING FOR COPPER NEAR MW-12D 19
6.2 RECOMMENDED CHANGES TO REDUCE COSTS 19
6.2.1 RE-EVALUATION OF CLEANUP CRITERIA 19
6.2.2 ELIMINATION OF THE CYANIDE REMOVAL SYSTEM 19
6.2.3 ELIMINATION OF THE METALS PRECIPITATION SYSTEM 19
6.2.4 DELISTING METALS PRECIPITATION SLUDGE 20
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT 21
6.3.1 CHANGES TO MONITORING PROGRAM AND DATA EVALUATION PROTOCOLS 21
6.3.2 VERIFICATION OF WELL ELEVATIONS AND DEPTHS 21
6.3.3 ADDITIONAL MONITORING POINTS 21
6.3.4 LOW-FLOW SAMPLING 21
6.3.5 ELECTRONIC DATA MANAGEMENT 22
6.3.6 EXPANSION OF WELL SAMPLING PROGRAM 22
6.3.7 MEDIA REPLACEMENT FOR TERTIARY FILTER 22
6.3.8 CONTROL MODIFICATIONS 22
6.3.9 CONDUIT RELOCATION 22
6.3.10 PIPING MAINTENANCE 23
6.3.11 WELL MAINTENANCE 23
6.3.12 INDEPENDENT REVIEW OF ANALYTICAL DATA 23
6.3.13 TREATMENT PROCESS OPTIMIZATION 23
6.3.14 WASTE SLUDGE STORAGE OPTIONS 23
6.4 MODIFICATIONS INTENDED TO GAIN SITE CLOSE-OUT 24
6.4.1 ESTABLISH CLOSURE CRITERIA 24
6.4.2 ADDITIONAL SOURCE AREA IDENTIFICATION/REMOVAL 24
6.5 OUTSTANDING VALUE ENGINEERING PROPOSAL FOR ADDING A SECOND AIR STRIPPER ... 24
6.6 CHANGES IN CURRENT APPROACH TO SITE REMEDIATION REQUIRING REDESIGN 24
6.6.1 PERMEABLE REACTION WALL 24
6.6.2 ADDITIONAL VOLATILE ORGANIC SOURCE REMOVAL 25
6.6.3 INSTALLATION OF A SUBSURFACE BARRIER 25
7.0 SUMMARY 26
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List of Tables
Table 3-1. Action levels
Table 7-1. Cost summary table
List of Figures
Figure 1-1. Site layout (original)
Figure 1-2. Site layout (current)
Figure 4-1. Observed concentrations, MW-05D
Figure 4-2. Observed concentrations, MW-12D
VI
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1.0 INTRODUCTION
1.1 PURPOSE
The US Environmental Protection Agency's (USEPA) Technology Innovation Office (TIO) and the
US Army Corps of Engineers (USAGE) Hazardous, Toxic, and Radioactive Waste Center of
Expertise (HTRW CX) are cooperating in the demonstration of the USAGE Remediation System
Evaluation process at Superfund sites. The demonstration of the RSE's is part of a larger effort by
TIO to provide USEPA Regions with various means for optimization, including screening tools for
identifying sites likely to benefit from optimization and computer modeling optimization tools for
pump and treat systems, such as the MODMAN code.
The Oconomowoc Electroplating Company Superfund site was chosen based on initial screening of
pump and treat systems managed by USEPA Region 5 and represented a site with relatively high
operation cost and a long projected operating life. One or two sites in Regions 4 and 5 will be
evaluated with RSE's in the first phase of this demonstration project. A report on the overall results
from these demonstration sites will also be prepared and will identify lessons learned, typical costs
savings, and a process for screening sites in the USEPA regions for potential optimization savings.
The RSE process is meant to identify cost savings through changes in operation and technology, to
evaluate performance and effectiveness (as required under the NCP, i.e., and "five-year" review),
assure clear and realistic remediation goals and exit strategy, and verify adequate maintenance of
Government owned equipment. This report provides a brief background on the site and current
operations, a summary of the observations made during a site visit, and recommendations for changes
and additional studies. The cost impacts of the recommendations are also discussed.
1.2 TEAM COMPOSITION
The team conducting the RSE included:
Lindsey K. Lien, Environmental Engineer, USAGE HTRW CX
Dave Becker, Geologist, USAGE HTRW CX
Kathy Yager, HQ EPA TIO
Rob Greenwald, HSI GeoTrans (EPA TIO's contractor)
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1.3
DOCUMENTS REVIEWED
Author
US EPA
Dames and Moore
B & V Waste Science
and Technology
Group
St. Paul District Corps
of Engineers, and
Analytical Process
Laboratories
Ebasco Services
Incorporated
APL Environmental
APL Environmental
APL Environmental
Date
9/20/90
9/28/92
??
12/22/98
6/1/90
2/15/90
2/15/00
9/96-6/97,
7/98-12/99
Title/Description
Record of Decision, Oconomowoc Electroplating
Company Superfund Site, Ashippun, Wl, September
20, 1990 (and two non-applicable ESDs)
Predesign Engineering Report, Oconomowoc
Electroplating Company Superfund Site, Ashippun, Wl
Final Plans and Specifications, and Design Analysis,
Oconomowoc Electroplating Company Superfund Site,
Ashippun, Wl,
Purchase Order DACW37-99-M-0057
Draft Feasibility Study, Oconomowoc Electroplating
Company Superfund Site, Ashippun, Wl
Monthly Operation and Maintenance Report for
January, 2000
Monthly Monitoring Report for January, 2000
Tabulated Sampling Results
1.4 PERSONS CONTACTED
Craig Evans, Project Manager, USAGE St. Paul District
Steve Brossart, USAGE St. Paul District, Winona Area Office
James Chang, Program Manager, APL Environmental
Dean Groleau, Plant Superintendent, APL Environmental
Tony Goodman, Plant Operator, APL Environmental
Paul Kozol, Wisconsin Department of Natural Resources
Steve Padovani, RPM, EPA Region V
Dion Novak, RPM, EPA Region V
1.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS
1.5.1 LOCATION
The site is located at 2572 Oak Street, Ashippun, Wisconsin, an unincorporated town approximately
7 miles north of the city Oconomowoc and 40 miles west-northwest of Milwaukee. The site occupies
4 acres between Oak and Elm Streets and is bounded on the northwest by Eva Street and on the
southeast by the maintenance yard for the Town of Ashippun. Davy Creek and associated wetlands
lie southwest of the site across Elm Street and approximately 6.5 acres of these wetlands were
originally impacted by site operations. The site is now relatively flat except for linear berms on the
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northwest, northeast and southeast sides of the site, and slopes gradually toward Davy Creek. The
original and current site layouts are shown on Figures 1-1 and 1-2.
1.5.2 POTENTIAL SOURCES
The Oconomowoc Electroplating Company operated at the site from 1957 to 1991. The company
performed metal cleaning and plating operations involving the use of solvents, cyanide, chromium,
cadmium, nickel, tin, zinc, and copper. Process wastes were discharged at various locations around
the plant, into low areas between the plant and the town's Maintenance Yard, through wastewater
lagoons in the western part of the site, and into the wetlands southwest of the plant. As a result of
the waste disposal activities, contaminated soil, sediment, and ground water were widely detected
around the site and in the neighboring wetlands. Between 1991 and 1994, various removal actions
were conducted to remove the plant buildings, lagoon contents (including supernatant and sludge),
contaminated soils, and contaminated sediments from the wetlands.
1.5.3 HYDROGEOLOGIC SETTING
Ground water occurs in glacial till composed of unconsolidated sands and silty sands with occasional
sandy silts and silty clay layers. Bedrock is encountered between 25-50 feet below grade and is
comprised of shale or dolomite of the Maquoketa Shale Group. Hydraulic conductivities of the
unconsolidated materials based on slug tests ranged from 2E-4 to 7E-3 cm/sec and transmissivity
based on the pump test conducted during the Pre-Design Investigation was 1.7 sq. cm/sec. The
hydraulic conductivity based on the pump test, assuming an aquifer thickness of 20 feet was 2.8E-3
cm/sec. Depths to water range from approximately 8 to 0.5 feet below the surface. Ground water
flow varied from south to west prior to extraction system operation. Flow directions under pumping
conditions have not been documented, but are expected to be somewhat radial to the extraction wells
based on the relatively flat background hydraulic gradient. Gradients under non-pumping conditions
range from 0.001 to 0.006. Ultimately, ground water discharges to the wetlands of the Davy Creek
floodplain.
1.5.4 DESCRIPTION OF GROUND WATER PLUME
The ground water plume was defined during the Remedial Investigation and in the Pre-Design
Investigation and consisted primarily of various chlorinated organics, including trichloroethene
(TCE), perchloroethene (PCE), 1,1,1 trichloroethane (1,1,1 TCA), and breakdown products of those
solvents. Maximum levels of TCE at that time exceeded 10,000 ug/L along the southeast boundary
of the site and southwest of the site near the wetlands. Nickel, cadmium, and cyanide were also
present at significant levels at the time the RI was completed. The plume extended from the
northeast side of the site southwest into the wetlands and from the Town of Ashippun Maintenance
Yard west toward the residences along Elm Street northwest of Eva Street. Currently, maximum
concentrations typically range between 2,000 and 3,000 ug/L total VOCs. TCE, 1,1,1 TCA, and their
breakdown products predominate and the highest levels are found in the central part of the former
Oconomowoc Electroplating site near EW-4 and EW-5. Following extensive excavation of site soils
and impacted sediments in the wetlands in the mid-1990s, concentrations of metals in ground water
have declined. Sporadic occurrences of nickel, copper, and lead above standards are noted in various
wells (see section 5.2), though it should be noted that samples are not filtered.
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2.0 SYSTEM DESCRIPTION
2.1 SYSTEM OVERVIEW
The remediation system consists of:
5 extraction wells
extraction pumps
transfer piping to the treatment facility
20,000 gallon equalization tank
a cyanide removal system consisting of a two stage alkaline chlorination system
metals precipitation consisting of a 350 gallon rapid mix tank, 1050 gallon
flocculation tank, followed by an inclined plate clarifier with 288 square feet of
settling area
a pH adjustment tank
a continuous backwash, 4 feet diameter, 12 feet high tertiary sand filter and 525
gallon storage tank
a six tray stacked air stripper
2-1000 pound granular activated carbon adsorbers operated in series
a 3000 gallon effluent storage tank
an NPDES composite sampler monitoring station
a 30 cubic feet center feed recessed plate filter press, and 10,000 gallon sludge
holding tank, and 6000 gallon press filtrate holding tank
discharge to an infiltration gallery in the wetland area located in the floodplain of
Davy Creek
The system was designed to treat a flow rate of 35 gpm from the five extraction wells including 5
gpm from the plant processes such as filter backwash and filter press filtrate. The actual flow rate
from the well field ranges from 20 to 30 gpm, and with recycle flows, generally averaging
approximately 30 gpm. Iron bacteria fouling problems in the extraction well network has
intermittently reduced flow to the plant. Excessive scale formation in the alkaline chlorination
cyanide destruction process has also resulted in treatment downtime due to the need to clean the
scale formed on the tank walls approximately every two weeks.
2.2 EXTRACTION SYSTEM
The extraction system includes five wells, four of which were installed during construction of the
treatment plant. These four wells are 6-inch diameter and have approximately 30 feet of screen,
extending from approximately seven feet below the surface to a five-foot-long sump set into bedrock.
The other well was installed for a pump test conducted during the Pre-Design Investigation. This
well is significantly shallower - only 15 feet deep. The wells are connected to the treatment plant by
a common header of 1 to 1.5-inch pipe inside 4-inch containment pipe. Each well is supplied with a
Grundfos submersible pump. The well head is completed above grade inside a hinged, locked, and
insulated fiberglass housing. The connections to the extraction piping, flow-control valve, flow
meter, and sample port are all contained inside the housing. Power and control lines are run in
below-grade conduits parallel to the collection piping.
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2.3 TREATMENT SYSTEM
Groundwater is extracted from a series of five wells and discharged to a 20,000-gallon equalization
storage tank. This tank also functions as a sump discharge tank where the recycle stream from the
treatment facility sump, as well as granular activated carbon (GAC), filter press filtrate, and sand
filter backwash water. Flow is then pumped via diaphragm pumps to the first stage of the alkaline
cyanide oxidation process. In the first stage of the process (CRT 201), sodium hydroxide is added to
adjust the pH to approximately 9 concurrently with the addition of sodium hypochlorite. Following a
retention time in CRT 201 of approximately 30 minutes at a flow rate near 30 gallons per minute, the
overflow is directed to a second tank (CRT 211) with a detention time of approximately 70 minutes
where additional sodium hypochlorite is added and the pH is further adjusted to approximately 10.5
using sodium hydroxide. The final step of the cyanide removal takes place in a third basin with a
detention time of 35 minutes at 30 gpm, where additional sodium hydroxide is added to complete the
pH adjustment to >11. This allows the noncomplex cyanide to escape from the solution while
providing a favorable environment to precipitate metal hydroxides from solution. Cyanide gas is
removed from the covered basins via a small induced draft fan, and discharged to the atmosphere.
Polymer is added to the water in a flash mix step and then allowed to slow mix for 30 minutes prior
to settling in a 288 square foot inclined plate clarifier. Sludges produced are transferred to a sludge-
settling tank and allowed to consolidate in the bottom of the unit prior to being pumped to a 30 cubic
foot plate and frame filter press. The sludge cake was analyzed and found to be below TCLP
concentrations for metals and the organics listed in Table 3-1. The State of Wisconsin considers the
sludge to be a listed F006 waste (due to the historical use of the site as an electroplating facility),
which requires disposal at a RCRA Subtitle C landfill. Following pH adjustment with sulfuric acid,
the water is filtered through a 4-foot diameter continuous backwash sand filter, before being
processed through a 6-tray low profile air stripper (AS) for volatile organics removal. The AS
effluent is treated through 2 GAC units in series, each containing 1000 pounds of GAC. The effluent
is then discharged via a 3-inch force main to a percolation bed located below the surface water level
in the wetland area in the floodplain of Davy Creek.
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3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE
CRITERIA
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
The goal of the treatment system, as documented in the ROD, is to both contain and remediate the
ground water to preventive action limits (PALs). The plant is required to meet discharge standards
set in Wisconsin Department of Natural Resources wastewater discharge permit DOCb 44976. The
treated water is discharged via a subsurface infiltration gallery. It is not clear what the bases are for
the values set in the permit, since the required levels for a few parameters are lower than the PALs
(e.g., cadmium, lead) If the limits are based on the potential aquatic (surface water) impacts in the
wetlands, it should be noted that the levels currently observed in the ground water under the
wetlands, in some cases, greatly exceed these values. The current limits for operations requires CN
concentrations be reduced to less than 40 ug/L in treated water, however it was stated during the site
visit that the state regulator was requiring a more stringent discharge level for CN in the plant
discharge of 10 ug/L. Metals concentrations are consistently below the PALs with the exception of
nickel, which generally occurs at an influent concentration of 40 ug/L, well above the 20 ug/L PAL
but well below the current state enforcement standard of 100 ug/1. No points of compliance have
been identified for the groundwater. There are potential users of ground water in the immediate
vicinity of the plume, across Eva Street. The ultimate future receptor of the contaminated water, if
not removed by pumping, is Davy Creek and the associated wetlands.
3.2 TREATMENT PLANT OPERATION GOALS
The current contract for operations calls for the plant to operate 24 hours per day, seven days a week
while treating water from all designated active extraction wells. Two personnel attend the facility for
one shift Monday through Friday, and one individual is present during a single shift on Saturday and
Sunday.
3.3 ACTION LEVELS
Discharge/Clean-up standards as identified in the ROD are as shown in Table 3-1:
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Table 3-1. Action Levels
PH
TSS
Arsenic
Barium
Cadmium
Lead
Mercury
Iron
Manganese
Nickel
Selenium
Silver
Thallium
Copper
Cyanide
Cyanide Free
Chromium Total
Zinc
1,1-Dichloroethane
1,1-Dichloroethene
1,2-Dichloroethane
1,2-Dichloroethene
1,2-Dichloroethene Cis
1 ,2-Dichloroethene Trans
Ethylbenzene
Methylene Chloride
Tetrachloroethene
1,1,1-Trichloroethane
1,1,2-Trichloroethane
Trichloroethene
Toluene
Xylenes Total
Vinyl Chloride
Ammonia Nitrogen
COD
Phosphorus Total
Nitrate + Nitrite
Permit
Standards
(ug/L)
monitor
monitor
5.0
400
0.5
1.5
0.2
monitor
monitor
20.0
10
10
0.4
monitor
40
monitor
10.0
monitor
85
0.7
0.5
7
20
140
0.5
0.5
40
0.5
0.5
68
124 ug/L
0.2 ug/L
monitor
monitor
monitor
monitor
PALs
(1990 ROD)
(ug/L)
5
1
5
0.2
25
500
40
5
2500
85
.024
.05
10
0.1
40
0.06
0.18
0.0015
Latest
PALs
Effective
1-1-1999
(ug/L)
5
400
0.5
1.5
0.2
150
50
20
10
10
0.4
130
40
10
2500
85
0.7
0.5
7
20
140
0.5
0.5
40
0.5
0.5
200
1,000
0.02
2.000
Enforcement
Standard
(1990 ROD)
(ug/L)
50
10
50
2
50
1,000
200
50
5,000
850
.24
.5
100
1
200
0.6
1.8
0.015
Enforcement
Standard
1-1-1999
(ug/L)
50
2,000
5
15
2
300
25
100
50
50
10
1,300
200
100
5,000
850
7
5
70
100
700
5
5
200
5
5
1,000
10,000
0.2
10.000
MW12B in December 1999 far exceeds any other value and should be verified.
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4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT
4.1 FINDINGS
In general, the RSE team found the system to be well operated and maintained. The observations and
recommendations given below are not intended to imply a deficiency in the work of either the
designers or operators, but are offered as constructive suggestions in the best interest of the EPA and
the public. These recommendations obviously have the benefit of the operational data unavailable to
the original designers.
4.2 SUBSURFACE PERFORMANCE AND RESPONSE
Currently, analytical and water level data are received on paper from the lab of field and the data is
manually entered to tables on the computer at the treatment plant. The time necessary for this
tedious effort is significant. In using the compiled analytical data, it became apparent that there may
be data quality issues, transcription errors, and transposition of results in the tables. Some results
may also simply be outliers. For example, September 1998 monitoring well data included results for
recoverable hexavalent chromium. Several of the concentrations were extremely high (>20 ppm)
although total chromium was low. In the December 1998 sampling results, the values for MW14D
and MW15D may have been switched. Switching the reported concentrations back would result in
levels in both wells that are more consistent with the historical levels of contaminants. Finally, the
13-ppm value for nickel in
4.2.1 WATER LEVELS
Wells included in the late 1999 monitoring round were MW02D, MW05D, MW12B, MW12D,
MW13S, MW14D, MW15D, and MW-16S. Several other wells have been checked but found to be
dry. In March 2000, water levels were high enough to yield measurements from MW03S, MW05S,
MW06S as well as the those listed above. The water levels taken from monitoring wells have not
clearly indicated a capture of the contaminant plume. In particular, there are significant questions
regarding the capture of the chlorinated organic plume west of the site near MW15. In both the May
1999 and December 1999 water level measurements, there seems to be inadequate evidence of
capture in this area. Water levels in MW15 are lower than in MW06, which suggests a flow
component away from EW-2.
4.2.2 CAPTURE ZONES
The capture zone of a well pumping 6 gpm in a 25-foot-thick aquifer with a hydraulic conductivity of
2.8E-3 cm/sec (based on the pre-design pump test) and a natural gradient of 0.001-0.006 should be
1000-6000 feet wide (assuming no impacts from hydrogeologic barriers). In that case, the stagnation
point would range from 160 to 950 feet downgradient of the extraction well. Calculations are
attached as Appendix A. Given the great distance to the stagnation point projected for the aquifer
relative to the short distance from the extraction wells to the adjoining wetlands, it is almost certain
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that the extraction wells are drawing significant amounts of water from the adjacent wetlands. This,
coupled with any contribution to the extraction wells from the bedrock and infiltration, would limit
the capture zone width to values much less than the 1000-6000 feet per well projected by the simple
analysis. To address this, an analysis was performed using an equation from Bear (1979) to
determine the proportion of water contributed from an injection image well an equal (but opposite)
distance from the edge of the wetland. This analysis indicated that, assuming a distance of 30 feet
from well to the wetland, between 63% to 81% of the extracted water may be derived from the
wetland. This would reduce the capture zone width to between 360 and 1100 feet per well. This is
still large relative to the plume size.
4.2.3 CONTAMINANT LEVELS
Ground water samples are currently obtained from monitoring wells MW02D, MW05D, MW06S,
MW12B, MW12D, MW14D, MW15D, and MW16D. If not dry, samples are also obtained from
MW03S and MW05S. Although hydropunch sampling done during the pre-design investigation
indicated the limits of the plume, the plume is not well defined by the current monitoring system.
The primary concern appears to be chlorinated organics in ground water. The extent of the organics
plume is not clearly defined east of EW-3, MW05D, and EW-5, and is also not clearly defined west
of MW15D (within a residential neighborhood where wells are used for water supply). Levels of
TCE in MW15D, which is screened within the shallow aquifer, have consistently measured near 30
ug/L in this residential area. Residential wells are screened in the deeper bedrock aquifer, and
detections of TCE of approximately 0.5 ug/1 at these residential wells were mentioned during the site
visit. Monitoring well MW05D has consistently shown levels of a number of organics, particularly
TCE, above the PALs. Although concentrations in MW15D have been quite stable, there is evidence
for decreasing concentrations of TCE and 1,1 dichloroethane in MW05D as shown in Figure 4-1.
Monitoring results from monitoring wells in the wetlands, including wells MW16S and MW12D,
indicate that chlorinated organics (including 1,1,1 trichloroethane, 1,1 dichloroethane, 1,1
dichloroethene, trichloroethene, 1,2 dichloroethene, and vinyl chloride) exist under the wetlands at
levels significantly above the PALs. The concentrations have had a modest increasing trend, as
illustrated on Figure 4-2. These contaminants likely discharge to the surface water of the wetlands or
Davy Creek. The levels of vinyl chloride, dichloroethene, and 1,1 dichloroethane (degradation
products of TCE and/or 1,1,1 TCA) strongly suggest that the chlorinated organics are being actively
degraded in this (wetland) environment. Degradation and volatilization of chloroethane and vinyl
chloride may be rapid once the contaminants reach the surface water. This contamination is very
unlikely to be captured by the extraction system. The extraction system is, however, limiting the
amount of additional chlorinated organics reaching the wetlands. Metals do not appear to be a
significant problem at the site with a few exceptions. These include elevated copper in monitoring
well MW12D (>1 ppm) and levels of nickel in monitoring wells MW12D, plus MW-13S and
MW16S (in the wetland). Sporadic concentrations of nickel and selenium above PALs are observed
from other wells at the site, but other than the three monitoring wells cited above, there is no
consistent trend or pattern to their occurrence. Iron and manganese are usually present at levels
above other metals, especially in the wetland. The samples are not filtered and low-flow sampling
methods are not used at the site.
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4.3 COMPONENT PERFORMANCE
4.3.1 TREATMENT SYSTEM PERFORMANCE (I.E., DOWN-TIME)
The system does not have a contractual requirement for the plant to continuously treat water from all
active extraction wells for some minimum time percentage. The system has been up and running
about 85-90% of the time. Most of the downtime has been due to unscheduled maintenance events
such as cleaning biofouled wells, cleaning the scale from the cyanide removal system, and excess
filter backwashes caused by chemical feed problems.
4.3.2 WELLS
The extraction and injection wells have generally performed acceptably, although periodic
rehabilitation is necessary to maintain performance. The extraction wells have experienced fouling
due to biological growth. The extraction wells are periodically (every 3-6 months) rehabilitated
when total extraction flow rates drop significantly from the expected 25-30 gpm. The flows from
individual extraction wells are evaluated to determine which well(s) have lost the most capacity.
Extraction well 2 has recently been most plagued with fouling problems, but other wells have shown
problems. Rehabilitation has consisted of pump removal and cleaning, well swabbing, and
disinfection with hypochlorite. Rehabilitation is conducted by treatment plant staff. Electrical
outlets have been installed at each extraction wellhead to facilitate the process. Wellhead vaults
appear in excellent shape. A limited number of monitoring wells are included in the sampling and
water level measurement program. In part, this is due to some monitoring wells (MW03S, MW05S,
and MW06) being dry. In inspecting the monitoring wells, it was noted that several wells have
protective casings that have been bent (MW05S, MW01S, MW02D). It is not clear that the well
integrity has been compromised. Two wells (MW08, MW07) have evidence for frost "jacking"
which has lifted the concrete pad out of the ground. Plant personnel indicated that well MW04D has
a bailer stuck in the screen.
4.3.3 CARBON UNITS
Carbon run times have been shorter than expected. The reasons are not clear. Since the GAC is
regenerated, it may have been through numerous cycles and subsequent losses per regeneration cycle
may have reduced the capacity, or unexpected non-hazardous organic compounds (TOCs) may be
using up the GAC adsorption sites. Without expending significant effort, the cause is difficult to
ascertain. A value engineering proposal to add a second air stripper was recently submitted to which
would allow removal of the GAC component from the treatment process.
4.3.4 ALKALINE OXIDATION CYANIDE REMOVAL SYSTEM
The cyanide removal system has been an ongoing source of problems for the plant operations staff
since plant start up. The cyanide reaction tanks CRT 201/211 require isolation, draining and
cleaning due to CaCO3 scale buildup on the reaction vessel walls, floors and mixing equipment. The
scaling is so severe the units have to be taken out of service approximately every two weeks for
cleaning. The cleaning process involves draining the tanks, pressure cleaning the walls, floors and
mixers, then doing a confined space entry to physically scrape the scale from the walls, floors and
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other components in the vessels. Flow is diverted around the cyanide treatment equipment for a
minimum of one full shift during the semiweekly cleaning exercise. Cyanide effluent standards have
not been exceeded during these outages.
4.3.5 METALS PRECIPITATION SYSTEM
In general, the metals precipitation unit has been operating well with proper scheduled maintenance,
and has experienced few upsets. The primary problems associated with its operation have been
related to the chemical feed system probes fouling and low solids content in the sludge. The influent
contaminant concentrations have been very low, generally below the PALs, with the exception of
nickel which has consistently been 40 ug/L, or approximately twice the 20 ug/L PAL (but well below
the enforcement standard of 100 ug/1). The levels identified are suspect since the samples are
generally not filtered prior to analysis, and therefore may be related to sample turbidity. The sludge
handling system was designed for sludge with a much greater density than is currently produced by
the metals precipitation unit. Since the solids content is so low, management of the sludge blanket
has proven difficult. The existing sludge pumps and control system used to transfer settled sludge
from the parallel plate clarifier makes it difficult for the operators to maintain the fragile sludge
blanket using the existing pumps. The operators generally manually pump the sludge for a period of
time at the beginning of each occupied shift to reduce the potential for upsets. The sludge thickener
tank was sized for a higher solids sludge, which results in the need for the operators to decant the
liquid from above the sludge in the tank to the sump, which discharges to the influent tank EQT-100.
This allows the operators to accumulate approximately 4 feet of sludge depth in the thickener over a
two-week period allowing the operators to maximize the solids captured in the filter press. Prior to
this operational change the thickener had sludge capacity for one-half the filter press capacity.
Decanting a large volume of water through the sump and eventually back to the EQT-100 tank has
resulted in a sludge build-up within it that requires periodic removal via equipment designed with the
plant.
4.3.6 NEUTRALIZATION
Following the metals precipitation step, the pH is adjusted to <9 to neutralize the polymer previously
added, reduce the potential for scaling, redissolve any residual hydroxide precipitates, and reduce the
volume of acid needed for the final pH adjustment prior to discharge.
4.3.7 TERTIARY FILTRATION
The continuous backwash filters were designed to remove precipitate carryover from the metals
precipitation step, which will prevent plugging of down stream units. Unfortunately, short filter
cycles have plagued the tertiary filters. Sodium hydroxide crystallization in the NaOH pump suction
lines has resulted in low pH levels in the metals precipitation unit. The low pH results in poor metals
precipitation and consequently, poor solids removal in the sedimentation unit. The unsettled solids,
as well as high concentrations of polymer added to aid in the sedimentation, carry over into the
tertiary filter which causes binding within the filter, and eventually plugging. Due to the high
concentration of unused polymer binding the filter media, additional high flow rate back wash cycles
are needed. These backwash cycles are not normally required and generate excessive additional
volumes of backwash water that must be processed through the plant. The filter backwash flow is
discharged directly to the building sump that discharges to equalization tank EQT-100. During
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periods of excessive backwash frequency, equalization tank EQT-100 fills to the high level and shuts
down the extraction system and building sump pumps. Unfortunately the remaining equipment
including treatment facility feed pumps TFP 110/111, the tertiary filters and backwash pumps
continue operating and discharging to the sump, eventually causing an overflow onto the plant floor.
4.3.8 AIR STRIPPERS
The existing air stripper is functioning well with few unexpected problems. The unit is a Carbonair
model STAT 80, six tray air stripper which consistently reduces volatile organic contaminant
concentrations to below effluent limits, with the exception of TCE. TCE is reduced to below 2 ug/L
prior to polishing in the GAC units, which consistently reduce the concentration to below the 0.5
ug/L effluent standard. The strippers were designed to reduce TCE levels from approximately 1300
ug/L to < 2.0 ug/L while operating at a flow rate of 35 gpm, and an air to water ratio of 75:1.
Currently the TCE concentration into the unit is approximately 600 ug/L. The only unscheduled
maintenance is the need to inspect, and remove scale and precipitates from the trays every six months
which takes approximately 8 total hours of labor. Sulfuric acid is being fed upstream from the
stripper to reduce the pH <8, which prevents precipitation in the piping, stripper and GAC. Scaling
or fouling within the stripper has not been a problem.
4.3.9 PIPING
Piping within the plant subjected to acidic pH water was recently replaced with polyvinyl chloride
piping. The iron process water piping failed because the acidic pH leached the iron out of the piping.
No further problems within the plant have been experienced since the pipe replacement. The well
discharge collection piping has experienced numerous plugging problems caused by iron bacteria
accumulation within the lines. The lines are systematically cleaned when head loss in them exceeds
a predetermined value. The cleaning method consists primarily of high velocity flushing.
4.3.10 CHEMICAL FEED SYSTEMS
The chemical feed systems for the most part are operating properly with occasional unscheduled
maintenance required to maintain optimum operation. There are four primary chemical feed systems
in use at the Oconomowoc plant; acid, caustic, sodium hypochlorite, and polymer feed. Occasionally
the 20 percent sodium hydroxide solution forms crystals in the NaOH pump suction lines and
strainers. When this occurs, inadequate caustic is fed to the CN removal, and metals removal
processes. The metals precipitation unit does not form a hydroxide floe, and consequently when
polymer is added, no interparticle binding occurs. The excess polymer is discharged to the tertiary
filters where the polymer attaches to the sand media, which binds together, resulting in the formation
of "mud balls", that eventually plug the filter. Generally when sand filters are subjected to high
polymer dosages, the media must be replaced. Following some improvements to the polymer feed
system and polymer dilution system by the operating contractor, the system has worked well.
4.3.11 SLUDGE HANDLING AND TREATMENT
The sludge handling systems primary purpose is to dewater the sludge generated by the metals
precipitation system. The metals precipitation process is discussed in paragraph 4.3.5. The primary
components in the system are the 30 cubic foot plate and frame filter press, a 10,000 gallon sludge
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holding tank (ST-820), a 6,000 gallon press filtrate holding tank (PFT-820). The concentration of
solids in the sludge is lower than expected which requires the staff to periodically decant a portion of
the supernatant from above the sludge accumulation. After the sludge depth reaches approximately
four feet, an adequate volume of sludge is available for one filter pressing cycle. Enough sludge is
generated from the metals precipitation process to facilitate a press cycle once every other week.
The cake is dropped into a roll off dumpster located below the press. Cake is accumulated on site for
90 days, which is in accordance with RCRA regulations, prior to disposal at a Subtitle C approved
facility in Illinois for $350 per ton. The disposal of this material as a listed waste is based on the
previous electroplating activities at the site, and not because of any constituent levels in the material.
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
COSTS
4.4.1 UTILITIES
Heat and Electricity costs for the USAGE contract period 1 November 1998 to 30 October 1999 were
$5,000 and $13,000 respectively, or $18,000 annually.
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS
Based on the contract period 1 November 1998 to 30 October 1999 are as follows:
Chemicals
Polymer $ 1,700
SulfuricAcid $19,000
Sodium Hydroxide $13,000
Sodium Hypochlorite $ 3.500
Subtotal Chemical Costs $37.200
Granular Activated Carbon $13.000
Sludge Disposal
Total Annual Cost Non-Utility Consumables
4.4.3 LABOR
The staff consists of a plant superintendent and one operator. Annual operation costs are
approximately $280,000 including overtime.
4.4.4 CHEMICAL ANALYSIS
Sampling of approximately 10 monitoring wells occurs quarterly. Treatment plant influent/effluent
concentrations are determined weekly. Analysis for VOC's is by methods 8260. Arsenic, barium,
cadmium, chromium, lead, mercury, nickel, selenium, silver, thallium, and zinc are by SW-846
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methods. Cyanide is analyzed by method 624. Estimated annual cost for these analyses is $70,000.
The existing staff conducts sampling.
4.4.5 OTHER COSTS
Total annual O&M costs now exceed $471,000. Other items beyond those listed above such as
office supplies, safety equipment, and quick turn around sampling are approximately $28,000.
4.5 RECURRING PROBLEMS OR ISSUES
4.5.1 CYANIDE SYSTEM CLEANING
The cyanide reaction tanks CRT 201/211 require isolation, draining and cleaning due to CaCO3 scale
buildup on the reaction vessel walls, floors and mixing equipment. The scaling is so severe the units
have to be taken out of service approximately every two weeks for cleaning. The cleaning process
involves draining the tanks, pressure cleaning the walls, floors and mixers, then doing a confined
space entry, to physically scrape the scale from the walls, floors and other components in the vessels.
Flow is diverted around the cyanide treatment equipment for a minimum of one full shift during the
semiweekly cleaning exercise.
4.5.2 SUMP OVERFLOW
Short filter runs have plagued the tertiary filters. Sodium hydroxide crystallization in the NaOH
pump suction lines has resulted in low pH levels in the metals precipitation unit. The low pH results
in poor metals precipitation and consequently, poor solids removal in the sedimentation unit. The
unsettled solids, as well as high concentrations of polymer added to aid in the sedimentation, carry
over into the tertiary filter causing very short filter runs. Due to the high loading on the filter,
excessive volumes of backwash water are generated which must be processed through the plant. The
filter backwash flow is discharged directly to the building sump that discharges to the head of the
plant, equalization tank EQT-100. Equalization tank 100 then fills up and shuts down the extraction
system and building sump pumps, but not the treatment facility feed pumps TFP 110/111 which
causes the plant to continue operating and the sump to continue to fill, and eventually flood the plant.
4.6 REGULATORY COMPLIANCE
There are no known exceedances of regulatory criteria for treatment and disposal. All sludge is
transported to a RCRA facility. Many of the analytical parameters measured in the influent,
however, are below the treatment standards.
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4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL
CONTAMINANT/REAGENT RELEASES
Based on information made available to the team, there have been a few controlled releases of
contaminated water within the facility during operation of the plant. On several occasions, the sump
pumps shut down after overfilling the equalization tank (EQT 100). When power to the sump pumps
is interrupted the pumps from EQT 100 continue to operate, as do the filter backwash pumps, the
latter of which discharge to the sump resulting in plant flooding.
4.8 SAFETY RECORD
The plant appears to have had an excellent safety record.
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
The concentrations of TCE in MW15D (typically on the order of 30 ug/1) suggest that a portion of
the plume is present in the shallow aquifer below the nearby residences. Furthermore, there is not
convincing evidence to suggest that the groundwater plume in the vicinity of MW15D is delineated,
nor is there convincing evidence that this area of contamination is captured by the extraction system.
The domestic wells in the area produce water from the deeper bedrock aquifer and, to the extent
allowed by the residents, the wells are sampled.
5.2 SURFACE WATER
There may be current ecological exposure to ground water or surface water contaminated with metals
and chlorinated organics in the wetlands southwest of the site. The chlorinated organic
concentrations are unlikely to be significant in the aquatic environment and do not exceed freshwater
screening levels. Note that constructed wetlands similar to the natural wetlands adjacent to the site
are used to treat water contaminated with organics. Also, it does not appear that the intent of the
current system was to remediate the VOC's within the wetlands southwest of the site. With respect
to metals, levels of copper in ground water from MW12D do significantly exceed freshwater criteria
(screening levels are typically lower than 10 ug/L and Ambient Water Quality Standard is 11) and
exceed the PAL (130 ug/L) and Enforcement Standard (1300 ug/L) for ground water. It is possible
that the copper will be removed with the formation of iron hydroxides or by complexing with humic
acids. Also note that these elevated copper concentrations are generally restricted to one monitoring
well located within the wetlands, and these concentrations in groundwater would be subject to
significant dilution within the wetlands.
5.3 AIR
Although there is no treatment of the off gas from the air stripper and process tanks, this discharge to
the atmosphere is very small. At 30 gal/min and 900 ug/L VOC's, atmospheric loading is only 0.15
kg/day. It seems unlikely that the air discharge poses a risk to the nearby population.
5.4 SOILS
It appears the sources identified in the ROD that have been removed under the previous operable
units have effectively removed the source of the contamination. The concentrations of metals and
cyanide in the aquifer appear to be under control. Concentrations of metals in the plant influent are
under the preventative action limits (PALs) with the exception of nickel, and occasionally total
chromium.
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5.5 WETLANDS
Contaminated sediments in the wetlands were previously excavated and the wetlands were
subsequently restored. Healthy vegetation and clear surface water was observed at the time of the
site visit. It appears that generally the action was successful.
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6.0 RECOMMENDATIONS
6.1 RECOMMENDED STUDIES TO ENSURE EFFECTIVENESS
6.1.1 CAPTURE ZONE ANALYSIS
A formal capture zone analysis should be performed on the basis of measured water levels, plus
additional hydrogeologic analysis (i.e., analytical tools and/or a simple groundwater flow model).
The goal is to better understand the capture zone dynamics at the site and evaluate the adequacy of
the current capture zone. This should include an assessment of the contribution of water from the
wetlands and the subsequent impact on the capture zone.
It is recommended that this analysis also include simple response (pump) tests for a couple of
representative extraction wells, including EW-2, EW-4 and/or EW-5. These wells are constructed
differently than the pump test well (EW-4) and are screened over a longer interval. The tests should
be conducted following a system shutdown (done for other reasons such as maintenance) and the
recovery of ground water levels to a "static" condition. The test should just consist of the restarting
of the pump and the simultaneous monitoring of the draw down response, on a logarithmically
increasing interval, in nearby monitoring wells over the course of 1-3 days. For EW-2, suggest that
MW06, MW03, and MW02S be monitored. For EW-3, suggest that MW05 and MW05D be
monitored and for EW-5 suggest that MW09S be monitored. Based on the draw down response, the
transmissivity and storage coefficient should be computed for the location. Any indication of a
boundary effect (i.e. the wetlands) should also be identified. These results can be used to predict the
aquifer response and capture zone for each well compared to the existing plume.
These tests could be done with existing treatment plant personnel at a cost of approximately $800 per
well (8 hrs * $45/hour * 2 persons + $80/day rental of recorder/transducers). Data analysis for would
need to be done by a hydrogeologist or engineer at an estimated cost of approximately $2,000 (32
hours * $60/hour). Total cost of the pump tests would therefore be approximately $5,000. Costs of
the additional hydrogeologic analysis (i.e., analytical solutions, simple groundwater modeling) to
evaluate system-wide capture zones would cost approximately $10,000 additional.
The additional information on the site hydraulic conductivities provided by the simple pumping tests
will be invaluable in determining, by whatever means, what flow rates are necessary to capture the
contaminants most efficiently. The costs for the pump tests are extremely small compared to annual
costs for operations. A numerical ground water model could be used very effectively to determine
the optimal pumping configuration and to perform "what-if' analyses, especially if one were to
consider alternatives such as a permeable reaction wall or sheet pile.
6.1.2 PLUME DELINEATION WEST OF EVA STREET
As noted above, the concentrations of TCE in MW15D suggest that a portion of the plume is present
below the nearby residences, and there is no evidence that this is captured by the extraction system.
Additional delineation of groundwater contamination should be performed in this area through the
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installation of a few new monitoring wells at an estimated cost of $l,800/well. In addition,
groundwater sampling history from domestic wells should be compiled and evaluated. A more
formal sampling schedule for domestic wells in that area should be considered.
6.1.3 SURFACE WATER SAMPLING FOR COPPER NEAR MW-12D
Based on the observed high concentrations of copper in well MW12D, recommend that surface water
samples be collected near MW12D, if filtered samples suggest the copper to be dissolved, to
determine if copper concentrations in ground water may cause elevated levels in surface water.
Costs for conducting the surface water sampling and analysis would be less than $300.
6.2 RECOMMENDED CHANGES TO REDUCE COSTS
6.2.1 RE-EVALUATION OF CLEANUP CRITERIA
The RSE team recommends that the project staff document the discharge standards for the on site
treatment facility. An exit strategy needs to be established for each site treatment process.
6.2.2 ELIMINATION OF THE CYANIDE REMOVAL SYSTEM
The cyanide removal system can be removed with no impact to the environment or the remainder of
the remediation system. The existing alkaline oxidation cyanide removal system designed to remove
cyanide in the ionic (CN) or hydrogen cyanide (HCN) form, designated as free cyanide. Based on
data collected during January 2000, and conversations with the operators, the total cyanide
concentration in the influent is generally the below the discharge standard of 10 ug/L (the published
ROD effluent concentration was 500 ug/L, and the current PAL is 40 ug/L). Free cyanide was not
detected in the influent. The continued absence of free cyanide in the influent suggest that the
cyanide is present as a ferro or ferric cyanide form which is insoluble in water, very stable, and not
susceptible to oxidation .-This insoluble fraction is most likely being removed in the sand media filter
system, or potentially in the metals removal system. The cyanide removal efficiency in the filter
system should be evaluated at the site through the development of a strategic performance sampling
plan to prove to the state regulators the cyanide is not being discharged. Cost of additional cyanide
sampling would be approximately $2,000. Projected net annual chemical cost savings for deletion of
the cyanide oxidation system is $30,000, ($32,000 gross savings less $2000 in additional sampling
costs). Potential hazards afforded by the confined space entry into the equipment, and doing
strenuous work for prolonged periods in a confined space used as a reaction vessel for a chlorine
compound poses a greater safety hazard than the HTW cleanup, and offer further reason to remove
this treatment process.
6.2.3 ELIMINATION OF THE METALS PRECIPITATION SYSTEM
The chemical precipitation metals removal system is an expensive part of the overall system,
provides very little environmental benefit, and can probably be entirely removed in its present form
with little or no impact to the environment. The only metal consistently present in the influent
above the current PAL is nickel, which is usually present between 30 and 40 ug/L, compared to the
PAL limit of 20ug/L and an enforcement level of 100 ug/1. The 1990 ROD did not identify a clean
up level for nickel or identify it as a contaminant of concern. During January 2000, trivalent
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chromium was present in one influent sample at 20 ug/L, compared to the PAL of lOug/L, and an
enforcement standard of lOOug/L. The one excursion above the PAL was quite likely related to
sample turbidity. Iron is present in nuisance levels of 1.0 to 2.5 mg/L as is manganese, which is
present at approximately 0.2 mg/L. Iron and manganese at these levels tend to result in precipitates
forming that may foul treatment processes such as air strippers, sand filters and carbon adsorption
systems such that they require more frequent maintenance. Discussions with equipment vendors
indicate their equipment should be able to function properly with iron and manganese at these levels.
The existing system efficiently removes metals identified as COC's, down to the standards required
by the ROD, as well as nuisance chemicals such as iron and manganese to manageable levels, but
also removes a portion of the volatile organics in the liquid stream. Current estimated VOC removal
is 50%, based on verbal communications from the site operators. Disadvantages of the sludge
removal system include large quantities of chemicals must be purchased, fed, reacted with unwanted
inorganics, and handled safely and effectively prior to dewatering and disposal. These tasks prove to
be expensive and are the most hazardous activities at the treatment facility. The cost savings
allocated to this process includes only the cost of disposal. Based on 1 November 1998 to 30 October
1999 data, eliminating the current precipitation system could save approximately $25,000 in sludge
disposal costs annually. In order to maximize the use of existing plant equipment, and continue to
derive benefits from its use while reducing the volatile loading and fouling potential of downstream
units, other treatment options should be evaluated. These include:
a) Using the tanks and mixers as is without chemical addition, hoping the agitation
within the unit will allow for significant volatilization to reduce VOC
concentrations, and sufficiently oxidize the iron and manganese to below nuisance
levels. Cost for this option is essentially zero.
b) Incorporate option a, and in addition replace the existing mixers with a diffused
aeration system within existing CRT 201 and 211. Cost of this option is
approximately $15,000.
c) Enhance iron and manganese oxidation through the use of KMnO4. Capital cost for
this modification would be approximately $3,750. Costs include a new chemical
feed pump, KMnO4 storage, application point and mixer. Annual cost for a supply of
6 percent KMnO4 would be approximately $15,000.
d) Bypass the equipment. Minor piping modifications should cost about $1000. This
option would rely on air stripping and/or carbon to remove the VOC's to acceptable
levels and the tertiary filter remove complexed cyanide, nickel and trivalent
chromium that might be related to the influent turbidity.
6.2.4 DELISTING METALS PRECIPITATION SLUDGE
A petition meeting the formal de-listing procedure under 40 CFR 260.20 and 40 CFR 260.22 must be
filed to delist the sludge. The petitioner must prove the waste contains no constituents for which the
waste was initially listed by EPA, and the waste does not exhibit a characteristic under 40 CFR 261
Subpart C. The petition may be considered an administrative requirement or a substantive
requirement. However, since the waste is ultimately going to be managed off-site, it is suspected that
all administrative requirements would need to be met. A minimum of four rounds of existing or
future analytical data for the sludge will be required. The process is outlined in detail within the
above referenced regulations. The Regional Administrator has final authorization to approve a
petition to delist the sludge. A de-listed sludge could be managed off-site in a subtitle D landfill at a
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cost of $50 per ton versus the present cost of $350/ton at a RCRA subtitle C landfill. Potential
disposal cost savings afforded by delisting the sludge is approximately $17,000 annually, assuming
the cyanide and/or metals removal systems remain operational.
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT
6.3.1 CHANGES TO MONITORING PROGRAM AND DATA EVALUATION PROTOCOLS
It was not apparent that the responsibility for evaluating the subsurface performance of the system is
clearly assigned. Recommend that the project team use the EPA data quality objective process or the
USAGE Technical Project Planning process (refer to USAGE Engineer Manual EM 200-1-2,
available at http://www.usace.army.mil/inet/usace-docs/eng-manuals/em200-l-2/toc.htm) to refine
the strategy for monitoring performance at this site. Suggest that specific criteria for subsurface
performance be developed and a monitoring program to verify attainment of these criteria also be
assembled. The USAGE HTRW CX can advise on this process.
6.3.2 VERIFICATION OF WELL ELEVATIONS AND DEPTHS
Recommend also that sampling personnel sound the bottom of the wells to verify the depths of the
wells so that the wells' labels reflect the correct construction. For those wells that have shown signs
of frost jacking of the concrete pad, recommend that the top of casing in these wells be resurveyed,
and the wells be checked for internal damage by downhole camera if the surveys show impact to the
well casing itself. The costs for this would be less than $1,000.
6.3.3 ADDITIONAL MONITORING POINTS
Measurement of the water levels should be conducted in all available monitoring wells at the site,
including MW07, MW07, MW01S and D, MW09S, MW02S and D, MW04S and D (if the bailer
stuck in the well can be retrieved), and if possible, the fire well at the corner of Oak and Elm Streets.
Additional water level monitoring points would be useful, especially east of EW-3 and EW-5 and in
the central part of the site. The additional labor hours required for this activity would be minimal. If
some of the monitoring wells are typically dry, it may be useful to install slightly deeper replacement
wells. Estimated cost per shallow well is approximately $1,800. Therefore, 5 new wells for
purposes of water level measurements could be installed for approximately $9,000. Furthermore,
water level measurements (in feet above MSL) should be plotted for the shallow aquifer, at least
quarterly for one year, to evaluate the capture zone of the system under pumping conditions. This
should be compared to the potentiometric surface for pre-pumping conditions, which should also be
prepared. These analyses can be performed by a hydrogeologist or engineer for approximately
$3,000.
6.3.4 LOW-FLOW SAMPLING
Recommend that samples be obtained by low-flow sampling methods in accordance with EPA/540/S-
95/504, April 1996, Low-Flow (Minimal Drawdown) Ground-Water Sampling Procedures (available
on the web in Adobe format at http://www.epa.gov/ada/issue.htmn. If this is not feasible,
recommend that both filtered and unfiltered samples be obtained for one or two sampling rounds to
better identify the component of the total metals concentrations derived from leaching of metals in
suspended solids. This would double the costs for metals analysis for those rounds.
21
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6.3.5 ELECTRONIC DATA MANAGEMENT
Recommend that analytical data for both process and subsurface monitoring be managed
electronically through the use of a database, or better, a geographic information system. The current
operator is proposing the development of such a system and we support the effort. The electronic
transfer of analytical results from the lab to the database should be investigated.
6.3.6 EXPANSION OF WELL SAMPLING PROGRAM
Recommend that additional sampling for one or two rounds be conducted from other wells at the site
to expand the horizontal and vertical definition of the plume, including the upgradient side of the
extraction system. The additional sampling should include wells MW02S, MW03D, MW09S,
MW04S or MW04D, and MW01S or MW01D. This would increase sampling costs by an estimated
$2,500 per round, including labor and analyses.
6.3.7 MEDIA REPLACEMENT FOR TERTIARY FILTER
The tertiary filter media is likely partially fouled due to excess polymer fed to the unit during caustic
feed malfunctions to the cyanide and metals removal treatment equipment. Cost for this modification
is approximately $3,250.
6.3.8 CONTROL MODIFICATIONS
Remote System Monitoring. Because of the frequent alarms the RSE team recommends a remote
monitoring system tied to the existing in plant computer monitoring system to be installed. This
improvement will allow on-call staff to evaluate the severity of the alarms prior to mobilizing to the
site for corrective action. Cost for this change should be approximately $3000, but will depend upon
the computer purchased, and the cost of the software (modem communications, and process
monitoring software).
Shut Down Control Modifications. The treatment feed pumps (TFP 110/111) should be deactivated
either when the equalization tank (EQT-100) level or the sump level within the plant reaches the high
level. This will eliminate the current problem of overflowing the sump during frequent filter
backwashing caused by high headless in the filters. Other equipment such as polymer and chemical
feed pumps should be evaluated to determine if it would be beneficial to switch them off if a high-
high level alarm activation event occurs. Cost of this modification should be approximately $2,000.
6.3.9 CONDUIT RELOCATION
Control conduits located in front of the granular activated carbon adsorbers should be removed and
relocated overhead and the control boxes relocated so the skid mounted units can be removed as
designed. This will give the contractor the option to store additional 1000 pound GAC units on site
for change out, or simply allow the delivery and replacement as necessary when breakthrough occurs,
whichever is the lowest cost. This is much simpler than the present labor intensive removal and
replacement process the operators currently use to manually remove and replace the GAC from a
spent column, and place it in drums to send off site for regeneration. Cost of the conduit relocation
will be approximately $2000. The cost of using portable exchangeable granular activated carbon
units is approximately equal to the cost of the existing system, assuming only a single carbon column
is changed out. Presently both columns are changed out each time a carbon delivery is made. This
22
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practice results in some savings due primarily due to labor savings and the need to replace the carbon
contactors after approximately 5 years of service.
6.3.10 PIPING MAINTENANCE
Piping between the wells and treatment plant should be cleaned periodically based upon past history.
6.3.11 WELL MAINTENANCE
Recommend that the maintenance program for the wells be developed that includes a preventative
maintenance approach. Refer to USAGE Engineer Pamphlet 1110-1-27 (Jan 2000). A copy can be
accessed at http://www.usace.army.mil/inet/usace-docs/eng-pamphlets/eplllO-l-27/toc.htm.
Suggest that the use of the blended heat and chemical treatment (BHCT) process be considered for
well rehabilitation. Draft guidance on well rehabilitation is in preparation at the USAGE HTRW CX
and a copy of the current draft of the guidance will be provided as soon as a draft-final version is
available.
6.3.12 INDEPENDENT REVIEW OF ANALYTICAL DATA
The chemical data from site and process monitoring should be subject to independent review for
usability and compliance with contract requirements. The USAGE can arrange for this support.
Typical costs for such a review would be $1500.
6.3.13 TREATMENT PROCESS OPTIMIZATION
The RPM should consider procuring the services of an independent contractor to look at optimizing
the treatment system, particularly the metals removal system, and explore potential technology
alternatives based upon the clearly defined discharge standards and compared to Table 3-1.
6.3.14 WASTE SLUDGE STORAGE OPTIONS
Evaluate the substantive RCRA Part B permit requirements for storage of hazardous waste in excess
of the 90 day criteria for a large quantity hazardous waste generator (LQG). An analysis should be
conducted to determine if the facility does in fact meet the definition of a large quantity generator (>
1000 kg/month) vs. small quantity generator (> 100 kg/month, < 1000 kg/month). Small quantity
generators can store up to 180 days (270 in certain situations). If the facility is a LQG, it may be
practical to meet additional substantive requirements to store the listed waste sludge on-site for up to
one (1) year. If substantive requirements can be met, then sludge can the aggregated over the course
of a year and consolidated transportation and disposal can be conducted on an annual basis, thereby
reducing the transportation related costs associated with quarterly shipments as a large quantity
generator. A review of the requirements under 40 CFR 264 should be evaluated to determine if any
requirements necessary under the standard are not being met by the facility. A cost analysis should be
conducted to determine any shortcomings to the 264 standards and what "cost of compliance" will
be. Modification of existing plans and any potential additional construction (i.e. secondary
containment for containers etc.) should be evaluated to determine if long-term storage is a cost
23
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effective option. It is anticipated the vast majority of requirements for "permitted storage" are
already being met. A cost for this task has not been formulated.
6.4 MODIFICATIONS INTENDED TO GAIN SITE CLOSE-OUT
6.4.1 ESTABLISH CLOSURE CRITERIA
The Oconomowoc treatment facility RPM and the State of Wisconsin must clearly define the closure
criteria. The RPM and State of Wisconsin must also evaluate and clearly document if the treatment
facility discharge standards are surface water or groundwater based.
6.4.2 ADDITIONAL SOURCE AREA IDENTIFICATION/REMOVAL
It is not clear that the soil removal previously completed at the site fully addressed the sources of the
VOC's. Recommend that the extent of the VOC's in the vadose zone be evaluated, through a careful
analysis of data generated during the soil removal, the remedial investigation, and pre-design
investigation. If there are areas of known VOC concentrations in soil outside of the soil removal
areas, recommend that soil gas sampling be conducted in those areas to confirm current presence. A
soil gas survey of areas not previously tested, but which appear to be consistent with the extent of
high levels of VOC's in ground water, would also be warranted. Based on these results, a decision
should be made as to the need for VOC source removal. Soil vapor extraction (SVE) would be the
most likely applicable technology. The shallow depths to water may require extraction trenches or a
surface cover (i.e. sealed asphalt cover directly on the soil). A soil gas survey could be conducted at
the site for approximately $5,000.
6.5 OUTSTANDING VALUE ENGINEERING PROPOSAL FOR ADDING A
SECOND AIR STRIPPER
The operations contractor has proposed removing the GAC units at the plant and installing a second
2 tray low profile air stripper similar to the 6 tray stripper currently at the facility. The existing 6
tray unit currently removes VOC's to below detection limits with the exception of TCE. The initial
concentration into the stripper is approximately 600 ug/L, and the effluent is approximately 2 ug/L.
The second stripper would reduce the TCE concentration to approximately 0.1 ug/L if installed, and
would reduce the dependence of the plant on the GAC for final polishing. The RSE team feels it is
too early to endorse this proposal until the other options, primarily the metals removal options are
fully evaluated.
6.6 CHANGES IN CURRENT APPROACH TO SITE REMEDIATION
REQUIRING REDESIGN
6.6.1 PERMEABLE REACTION WALL
The current use of pump and treat technology could be replaced by the use of a permeable reaction
(iron filings) wall installed along Elm Street. Given the low natural ground water flow rate, the
shallow depth to water and bedrock, and the predominance of chlorinated organics as the
contaminants currently of concern at this site, a PRW would be feasible at this site. Assuming a 24-
inch-thick wall with a length of 500 feet and a 25-foot depth, an estimated cost would be
approximately $ 1,500,000. Based on a $470,000/year O&M cost for the current system, less
$50,000/year for monitoring, which would still be required, a payback time (based on avoided costs
24
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of operating the treatment plant) of less than 4 years is indicated.
6.6.2 ADDITIONAL VOLATILE ORGANIC SOURCE REMOVAL
It is not clear that the soil removal previously completed at the site fully addressed the sources of the
VOC's. A soil gas survey of areas not previously tested, but which appear to be consistent with the
extent of high levels of VOC's in ground water, would be warranted. Based on these results, a
decision should be made as to the need for VOC source removal. Soil vapor extraction (SVE) would
be the most likely applicable technology. The shallow depths to water may require extraction
trenches or a surface cover (i.e. sealed asphalt cover directly on the soil). An SVE system to
remediate a one-half acre area adjacent to the southwest corner of the water treatment facility would
cost approximately $62,000 to install and have annual operating expenses of $6,000. Anticipated
treatment time would be approximately 2 years.
6.6.3 INSTALLATION OF A SUBSURFACE BARRIER
A sheet pile or slurry wall could be installed to prevent capturing water from wetlands and processed
by the pump-and-treat system. This could potentially cut total pumping rate by 50% or more. This
may be cost effective if the metals precipitation and cyanide systems could be eliminated. The
remaining volatile organics could most likely treated by GAC or air stripping alone. No costs have
been developed for this option due to its dependence upon implementation of other
recommendations.
25
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7.0 SUMMARY
In general, the RSE team found the system to be well operated and maintained. The system
cost effectiveness is subject to some questions. It appears contaminants are continuing to travel
towards the wetlands adjacent to the site and may continue to migrate in the shallow glacial till
aquifer into a nearby residential neighborhood served by individual (deep) domestic wells only
limited reductions of contaminant concentrations in ground water have been observed. A number of
changes in the remedial approach or the operations of the system are suggested to possibly reduce
future operations and maintenance costs and are summarized in the following Cost Summary Table
(Table 7-1).
The RSE team recognizes the difficulties in implementing changes to the permit under which
the system operates and the costs for obtaining regulatory acceptance. If the changes to the treatment
process and monitoring program could be proposed as a package to the State of Wisconsin, then
some time and cost efficiencies could be realized.
Table 7-1. Cost Summary Table
Recommendation
Capture Zone Analysis
Groundwater Modeling
Plume delineation west of
Eva Street (New Well)
Surface water sampling
for copper near MW-12D
Eliminate cyanide
treatment
Eliminate metals
precipitation 1
Alternate Metals Removal
Technologies for Fe, Ni &
Mn (select one)
a. no chemical addition
b. Aeration
c. KMn04
d. Bypass tankage
Alternate Sludge Disposal
(Use Subtitle D Landfill)2
Reason
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Cost reduction
Cost reduction
Cost reduction
Cost reduction
Additional
Capital
Costs
($)
$5,000
$10,000
$20,000
$300
$ 0
$15,000
$ 3,750
$ 1,000
$0
Estimated
Change in
Annual
Costs
($/yr)
$0
$0
$1,000
$0
($30,000)
($25,000)
$ 0
$ 0
$15,000
$ 0
($17,000)
Estimated
Change
In Lifecycle
Costs
($)*
$5,000
$10,000
$40,000
$300
($600,000)
($500,000)
$ 0
$ 15,000
$303,750
$ 1,000
($340,000)
26
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Table 7-1. Cost Summary Table (cont.)
Recommendation
Reduce Staffing 4
to three visits per week
(42% reduction)
Sound Bottom of Wells
Additional Water Level
Monitoring Points
Expand Well Sampling
Program
Replace Tertiary Filter
Media
Control Modifications
a. Emergency Stop
b. Remote Monitoring
Revise Carbon System
a. conduit relocation
b. change containers
with GAG
Analytical Data Review
Soil Gas Survey
Permeable Reaction Wall
SVE System3
Re-evaluate cleanup
criteria
Reason
Cost reduction
Technical
Improvement
Technical
Improvement
Technical
Improvement
Technical
Improvement
Effectiveness
Cost reduction
Technical
Improvement
Cost reduction
Technical
Improvement
Site Close-out
Site Close-out
Site Close-out
Site Close-out
Additional
Capital
Costs
($)
$3,000
$1,000
$12,000
$2,500
$ 3,250
$ 2,000
$ 3,000
$ 2,000
$ 0
$ 1,500
$5,000
$1,500,000
$62,000
$5,000
Estimated
Change in
Annual
Costs
($/yr)
($117,000)
$ 0
$ 0
$ 2,500
$ 0
$ 0
$ 0
$ 0
$ 0
$1,500
$ 0
($420,000)
$6,0003
$ 0
Estimated
Change
In Lifecycle
Costs
($)*
($2,337,000)
$1,000
$12,000
$52,500
$ 3,250
$ 2,000
$ 3,000
$ 2,000
$ 0
$ 31,500
$ 5,000
($6,900,000)
$74,000
$ 5,000
*estimated change in life-cycle costs assumes 20 years, no discount rate. Costs in parenthesis
imply a cost reduction.
1 Assumed savings is for sludge disposal
2 Assumed savings is for use of an alternate sludge disposal site and the metals precipitation unit is
still being used
3SVE costs based upon RACER cost estimating program, assume 2 years of operation
4Two staff personnel will visit the facility for 8 hours approximately three times per week. The
existing cyanide and metals removal systems are no longer required. $3000 reflects the cost for a
computer and software for remote monitoring when the site is not occupied.
27
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Figures
-------
Figure 1-1. Site layout (original).
V S
* I I 5 I I
I HHfs
if! ;=. n !.i h J
-------
J \ J \
F *S
UW-04D
t'
~a
50 E"™1
35 pISl
I
i
JCC
1-fIW
®
Tf latM.
®
^-e-'
-SB.
UUMC
«M
i * lj»-T
1-
MW-12B
W-I2S
®
®
MW-1«:
LEGEND
® = MONITORING WELL TREATABILITY SAMPLE LOCATIONS
® -' WETLAND SEDIMENT TREATABILITY SAMPLE LOCATIONS
® = LAGOON WATER TREATABILITY SAMPLE LOCATIONS
O = DEEP MONITORING WELL
* - SHALLOW MONITORING WELL
O = BEDROCK MONITORING OR OBSERVATION WELL
» = PUMP TEST WELL
S = MONITORING WELL INSTALLED BY EBASCO .
• - SHALLOW OBSERVATION WELL (PVC)
75
150
300
SUR\C* PREWREO ffr GLOBETROTTERS ENGINCERMG CORP. (OCT. "Sl-l
SCALE IN FEET
OCONOMOWOC ELECTROPLATING SUPERFUND SITE
ASHIPPUN, WISCONSIN
FIGURE 1-
DRAWN BY; MAB
DATE: JULY 1992
I DWG NO.: 13474011.US150103
I DAMES & MOOHE
OQ
to
O
-------
Figure 4-1. Observed concentrations, MW-05D
si---2=3
Figure 4.1
MW05D
i — chloroethane
1,1, DCA
1,1 DCE
n c1,2, DCE
A t1,2, DCE
»— TCE
Figure 4-2. Observed concentrations, MW-12D.
180
Figure 4-2
MW12D
1,1, DCA
1,1, DCE
o c1,2, DCE
t1,2, DCE
A 1,1,1,TCA
TCE
Vinyl Chloride
-------
Solid Waste and
Emergency Response
(5102G)
542-R-02-008b
October 2002
vwwv.clu-in.org/rse
www.epa.gov/tio
U.S. EPA National Service Center
for Environmental Publications
P.O. Box 42419
Cincinnati, OH 45242-2419
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