REMEDIATION SYSTEM EVALUATION
DOUGLAS ROAD LANDFILL
ST. JOSEPH COUNTY, INDIANA
Report of the Remediation System Evaluation,
Site Visit Conducted at the Douglas Road Landfill Superfund Site
October 29, 2003
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Office of Solid Waste EPA 542-R-04-031
and Emergency Response February 2004
(5102G) www.epa.gov/tio
clu-in.org/optimization
Remediation System Evaluation
Douglas Road Landfill
St. Joseph County, Indiana
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NOTICE
Work described herein was performed by GeoTrans, Inc. (GeoTrans) for the U.S. Environmental
Protection Agency (U.S. EPA). Work conducted by GeoTrans, including preparation of this report, was
performed under Dynamac Corporation Prime Contract No. 68-C-02-092, Work Service Request No. ST-
1-15. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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EXECUTIVE SUMMARY
A Remediation System Evaluation (RSE) involves a team of expert hydrogeologists and engineers,
independent of the site, conducting a third-party evaluation of site operations. It is a broad evaluation
that considers the goals of the remedy, site conceptual model, above-ground and subsurface performance,
and site exit strategy. The evaluation includes reviewing site documents, visiting the site for up to 1.5
days, and compiling a report that includes recommendations to improve the system. Recommendations
with cost and cost savings estimates are provided in the following four categories:
improvements in remedy effectiveness
reductions in operation and maintenance costs
technical improvements
gaining site closeout
The recommendations are intended to help the site team (i.e., EPA, the State, and the site contractor)
identify opportunities for improvements. In many cases, further analysis of a recommendation, beyond
that provided in this report, may be needed prior to implementation of the recommendation. The
recommendations are based on an independent evaluation by the RSE team and represent the opinions of
the RSE team.
The Douglas Road Landfill Superfund Site is located in St. Joseph County just north of Mishawaka,
Indiana. The site consists of a 16-acre capped landfill located on an approximately 32-acre lot (including
the land purchased in 1999 for a wetlands treatment area) that is bordered by farmland and wooded areas
to the west, residential and commercial properties south and east, and the Indiana Turnpike on the north
side. A reinfiltration basin is located in the southwest corner of the property.
Disposal in the landfill occurred between 1954 and 1979. The site team reported that trichloroethene
(TCE) and vinyl chloride were detected in about 10 downgradient residential wells, thereby initiating
investigation work at the site. The site was placed on the NPL on March 31, 1989. The following is a
brief chronology of site activities:
1994 - EPA took over the site lead and then initiated and completed the Remedial Investigation
(RI). The investigation indicated that the groundwater contaminant plume had migrated
about 3,800 feet southwest of the landfill.
1996 - About 95 residences in the area were connected to public water.
1/2000 - The landfill cap was completed.
10/2000 - A P&T system consisting of five extraction wells, treatment in three constructed wetlands
cells, and discharge to both an on-site reinfiltration basin and Juday Creek was
constructed and began full-scale operation.
10/2002 - The landfill gas collection system was activated.
This RSE report pertains to that P&T system and other site conditions that directly affect the performance
of this system.
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Ground water concentrations have decreased substantially since initial sampling in 1994, indicating the
initial success of the remedies. The ground water remedy has continued to extract and treat contaminated
ground water in an attempt to achieve its remediation objectives. The annual costs of operation are about
$177,800 per year.
The site team produces thorough and well prepared annual performance reports, and the RSE team notes
that the project management and reporting budget is very reasonable for the quality of reporting and
management. The proposed annual monitoring well sampling frequency and the analytical parameters are
appropriate for the site. The observations and recommendations contained in this report are not intended
to imply a deficiency in the work of either the system designers or operators but are offered as
constructive suggestions in the best interest of the EPA, the public, and the facility. These
recommendations have the obvious benefit of being formulated based upon operational data unavailable
to the original designers.
The RSE team suggests the following recommendations to improve system effectiveness:
Contaminant levels in monitoring wells are very low. Analysis of groundwater from
individual extraction wells would provide a good indication of contaminant levels in the
general area of the well, and the addition of sampling at the 5 extraction wells is
recommended on an annual basis (such sampling was previously performed form 1999 to
2002). This should require less than $1,500 per year.
A shallow groundwater investigation using direct-push technology in the areas around EXT-5
and MW-1 IS will provide information to the site team that will improve the site conceptual
model and allow better consideration of a site exit strategy. The combined direct-push
investigation, including developing a work plan and producing a report, should be completed
for less than $50,000
The RSE team suggests the following recommendations for cost reduction:
At least 25% of the site analytical program cost is due to the intensive Level IV QA/QC
protocol. With considerable long-term data available there is no need to exceed Level II
standards. Reducing the QA/QC level will save about $10,000 per year.
Discharge to Juday Creek requires an expensive annual sampling and evaluation program,
and alternatives should be considered. Discharge to Juday Creek may be eliminated if the
extraction rate is substantially reduced or if one of the current wetlands cells (which is no
longer needed to meet discharged standards) is converted into an additional reinfiltration
basin. Both of these options are discussed. Savings of approximately $30,000 per year might
be realized if the Juday Creek sampling program could be eliminated.
No recommendations are provided in the technical improvement category. Rather, the RSE team suggests
that emphasis be placed on the site closeout, effectiveness and cost reduction recommendations.
One recommendation is provided with regard to site closeout. The RSE team recommends developing an
exit strategy and provides two potential approaches. The risks that the ROD highlighted as the reasons
for active remediation are no longer present at the site. Therefore, one of the approaches includes
discontinuing the P&T system and monitoring for potential plume migration. Elevated arsenic levels had
not migrated off the site at concentrations of concern prior to P&T operation; therefore, it is highly
unlikely that elevated concentrations would migrate off of the site if the system were shut down. No
VOCs are consistently above PRGs in any monitoring or extraction well. Various VOCs (benzene, 1,2-
11
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DCA, and vinyl chloride) have periodically exceeded PRGs in 3 monitoring wells (MW-3S, MW-6S, and
MW-13S) since 1999. These exceedances are at relatively random levels near the PRO values and do not
represent a definable plume. The site team is encouraged to consider the exit strategy for the site before
implementing modifications to the treatment system.
The second approach includes continuing to operate only EXT-1 and EXT-2 due to the elevated arsenic
level. The site team may want to consider revising the PRG for arsenic to be consistent with the site
effluent standard or MCL if the pump and treat system is to continue operation until the arsenic PRG is
met.
A table summarizing the recommendations, including estimated costs and/or savings associated with
those recommendations, is presented in Section 7.0 of this report.
in
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PREFACE
This report was prepared as part of a project conducted by the United States Environmental Protection
Agency (USEPA) Office of Superfund Remediation and Technology Innovation (OSRTI). The objective
of this project is to conduct Remediation System Evaluations (RSEs) at selected pump and treat (P&T)
systems that are jointly funded by EPA and the associated State agency. The project contacts are as
follows:
Organization
Key Contact
Contact Information
USEPA Office of Superfund
Remediation and Technology
Innovation
(OSRTI)
Jennifer Griesert
1235 Jefferson Davis Hwy, 12th floor
Arlington, VA 22202
Mail Code 5201G
phone: 703-603-8888
griesertjennifer@epa.gov
GeoTrans, Inc.
(Contractor to USEPA)
Doug Sutton
GeoTrans, Inc.
2 Paragon Way
Freehold, NJ 07728
(732) 409-0344
Fax: (732) 409-3020
dsutton@geotransinc.com
IV
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TABLE OF CONTENTS
EXECUTIVE SUMMARY i
PREFACE iv
TABLE OF CONTENTS v
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 SITE LOCATION AND HISTORY 2
1.5.3 HYDROGEOLOGIC SETTING 4
1.5.4 RECEPTORS 4
1.5.5 DESCRIPTION OF GROUND WATERPLUME 4
2.0 SYSTEM DESCRIPTION 6
2.1 SYSTEM OVERVIEW 6
2.2 EXTRACTION SYSTEM AND INJECTION SYSTEM 7
2.3 TREATMENT SYSTEM 7
2.4 MONITORING PROGRAM 8
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE CRITERIA 9
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 9
3.2 TREATMENT PLANT OPERATION STANDARDS 10
4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT 11
4.1 FINDINGS 11
4.2 SUBSURFACE PERFORMANCE AND RESPONSE 11
4.2.1 WATERLEVELS 11
4.2.2 CAPTURE ZONES 11
4.2.3 CONTAMINANT LEVELS 12
4.3 COMPONENT PERFORMANCE 13
4.3.1 EXTRACTION SYSTEM WELLS, PUMPS, AND HEADER 13
4.3.2 CONSTRUCTED WETLAND 13
4.3.3 RElNFILTRATION BASIN 13
4.3.4 JUDAY CREEK DISCHARGE 13
4.3.5 CAP AND LFG SYSTEM 14
4.3.6 SYSTEM CONTROLS 14
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF O&M COSTS 14
4.4.1 UTILITIES 14
4.4.2 INFILTRATION BASIN MAINTENANCE 14
4.4.3 LABOR 15
4.4.4 CHEMICAL ANALYSIS 15
4.5 RECURRING PROBLEMS OR ISSUES 15
4.6 REGULATORY COMPLIANCE 15
4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL CONTAMINANT/REAGENT RELEASES
16
4.8 SAFETY RECORD 16
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT . 17
5.1 GROUND WATER 17
5.2 SURFACE WATER 17
5.3 AIR 17
5.4 SOILS 18
5.5 WETLANDS AND SEDIMENTS 18
6.0 RECOMMENDATIONS 19
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 19
6.1.1 SAMPLE EXTRACTION WELLS ANNUALLY 19
6.1.2 INVESTIGATE OFF-SITE SOURCES AND REMAINING DOWNGRADIENT IMPACTS 19
6.2 RECOMMENDATIONS TO REDUCE COSTS 20
6.2.1 REDUCE ANALYTICAL QA/QC REQUIREMENTS 20
6.2.2 CONSIDER CONVERTING THE WETLAND POLISHING CELL TO AN INFILTRATION BASIN . 20
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT 20
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT 20
6.4.1 DEVELOP AN EXIT STRATEGY 20
6.5 SUGGESTED APPROACH TO IMPLEMENTATION 21
7.0 SUMMARY 22
List of Tables
Table 7-1. Cost summary table
List of Figures
Figure 1 -1. Site Location Map
Figure 1-2. The Douglas Road Landfill, Surrounding Area, and Well Locations.
Figure 1-3. Monitoring Locations where Arsenic Exceeded PRGs in May 2003
Figure 1-4. Monitoring Locations where VOCs Exceeded PRGs and/or MCLs in May 2003
VI
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1.0 INTRODUCTION
1.1 PURPOSE
During fiscal years 2000, 2001, and 2002 Remediation System Evaluations (RSEs) were conducted at 24
Fund-lead pump and treat (P&T) sites (i.e., those sites with pump and treat systems funded and managed
by Superfund and the States). Due to the opportunities for system optimization that arose from those
RSEs, EPA OSRTI has incorporated RSEs into a larger post-construction complete strategy for Fund-lead
remedies. GeoTrans, Inc., an EPA contractor, is conducting these evaluations, and representatives from
EPA OSRTI are attending the RSEs as observers.
The Remediation System Evaluation (RSE) process was developed by the US Army Corps of Engineers
(USAGE) and is documented on the following website:
http://www.environmental.usace.armv.mil/library/guide/rsechk/rsechk.html
An RSE involves a team of expert hydrogeologists and engineers, independent of the site, conducting a
third-party evaluation of site operations. It is a broad evaluation that considers the goals of the remedy,
site conceptual model, above-ground and subsurface performance, and site exit strategy. The evaluation
includes reviewing site documents, visiting the site for 1 to 1.5 days, and compiling a report that includes
recommendations to improve the system. Recommendations with cost and cost savings estimates are
provided in the following four categories:
improvements in remedy effectiveness
reductions in operation and maintenance costs
technical improvements
gaining site closeout
The recommendations are intended to help the site team (i.e., EPA, the State, and the site contractors)
identify opportunities for improvements. In many cases, further analysis of a recommendation, beyond
that provided in this report, might be needed prior to implementation of the recommendation. The
recommendations are based on an independent evaluation by the RSE team, and represent the opinions of
the RSE team.
The Douglas Road site was selected by EPA OSRTI based on a recommendation from the associated EPA
Region. 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 consisted of the following individuals:
Rob Greenwald, Hydrogeologist, GeoTrans, Inc.
Peter Rich, Civil and Environmental Engineer, GeoTrans, Inc.
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The RSE team was also accompanied by the following observer:
Jennifer Griesert from EPA OSRTI
1.3
DOCUMENTS REVIEWED
Author
US EPA
US EPA
CH2M Hill
US EPA
CH2M Hill
CH2M Hill
CH2M Hill
Date
7/13/1995
5/3/1996
9/2000
9/1 1/2002
1/2003
9/2003
10/2003
Title
Record of Decision, OU1
Record of Decision, OU2
Interim Remedial Action Report, Volume 1& 2
First Five Year Review Report for Douglas Road
Landfill Superfund Site
Long-Term Remedial Action 2002 Performance
Report
Long-Term Remedial Action 2003 Performance
Report
Excel Spreadsheet of Sampling Data (updated
through September 2003)
1.4 PERSONS CONTACTED
The following individuals associated with the site were present for the visit:
Dion Novak, RPM, EPA Region 5
Kevin Herron, Indiana DEM
Dan Plomb, Project Manager, CH2M Hill
Roger Shields, Site Operator, CH2MHill
1.5
1.5.1
SITE LOCATION, HISTORY, AND CHARACTERISTICS
SITE LOCATION AND HISTORY
The Douglas Road Landfill Superfund Site is located in St. Joseph County just north of Mishawaka,
Indiana. The site consists of a 16-acre capped landfill located on an approximately 32-acre lot (including
the land purchased in 1999 for a wetlands treatment area) that is bordered by farmland and wooded areas
to the west, residential and commercial properties south and east and the Indiana Turnpike on the north
side. A reinfiltration basin is located in the southwest corner of the property. The location of the site and
the surrounding area are depicted in Figure 1-1. The site layout including monitoring wells, extraction
wells and pipelines is shown on Figure 1-2.
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In the early 1950s the landfill area was excavated and the gravel removed for use in the construction of
the turnpike. Uniroyal Plastics, Inc. leased the gravel pit and used it as a disposal repository between
1954 and 1979. From 1954 to 1971, the landfill was used to dispose of solvents, fly ash, paper, wood
stock, rubber and plastic scrap, and from 1971 to 1979, the landfill was used to dispose of fly ash only. In
December 1979 the landfill was closed. Site contamination was first discovered when trichloroethene and
vinyl chloride were detected in about 10 residential wells downgradient of the landfill.
1986 - The EPA nominated the site for inclusion on the National Priorities List.
1989 - The EPA placed the site on the NPL list and Uniroyal agreed to perform an RI/FS.
1991 - Uniroyal filed for bankruptcy and discontinued work on the RI/FS.
1994 - EPA took the site lead and completed RI work.
1995 - A Record of Decision (ROD) was issued for OU=1. The ROD selected remedy included
installation of a composite cap, collection of landfill gas, collection of surface water
drainage and groundwater, and source area monitoring.
1996 - A Record of Decision (ROD) was issued for OU2. The ROD selected remedy included
groundwater extraction, treatment by artificial wetland, and a combination of
reinfiltration and surface water discharge.
1996 - A city waterline was extended to provide water to about 95 homes that were impacted or
could potentially be impacted by site contamination.
1999 - Pumping was initiated in the downgradient extraction well EXT-5 to provide water for
wetland planting and acclimation.
2000 - Construction of the cap and P&T system was completed, and the P&T system began
operating.
2002 - Active landfill gas collection was initiated (the vents had been connected during cap
construction) after elevated methane levels were found on the east side of the landfill.
This RSE report pertains to the operating P&T system and other site conditions that directly affect the
performance of this system.
1.5.2 POTENTIAL SOURCES
According to site documents, Uniroyal disposed of approximately 302,400 gallons of liquid waste
including methyl ethyl ketone, acetone, tetrahydrofuran, toluene, hexane, and xylenes at the landfill. The
landfill has been capped, limiting leaching by precipitation, but the waste may periodically be in contact
with groundwater. The landfill gas system is removing methane as well as VOCs from the landfill waste.
Based on the concentrations of contaminants in groundwater adjacent to the landfill (both pre- and post-
cap) it appears that minimal contaminant source mass, if any, is reaching ground water. Monitoring well
MW-1 IS, located about 1,250 feet west of the landfill and slightly north of the historic plume location,
has had consistently higher tetrachloroethene (PCE) concentrations than any other monitoring wells and
no detections of any other VOCs. Additionally, PCE has not been detected in the landfill gas extraction
system effluent. No alternative contaminant source has been identified for the contamination at this well,
but no investigation has been conducted upgradient from MW-1 IS. Therefore, a source of PCE may exist
upgradient of MW- US.
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1.5.3
HYDROGEOLOGIC SETTING
The site overlies the prolific sand and gravel outwash deposits of the St. Joseph surficial aquifer. An
intermediate clay till deposit separates the aquifer into upper (shallow and intermediate) and lower (deep)
zones. Private water supplies and the public supplies for South Bend and Mishawaka rely on the St.
Joseph aquifer.
Groundwater at the site is typically present between 10 and 20 feet below ground surface. Monitoring
wells at the site are screened in shallow (about 15 to 30 feet bgs), intermediate (about 35 to 55 feet bgs)
and deep (about 90 to 100 feet bgs) zones. There is no confining unit between the brown sand of the
shallow zone and the brown sand and gravel of the intermediate zone. The gray sand and gravel of the
deep zone is separated from the upper zones by a 5 to 15 foot thick silty clay layer. Site groundwater
impacts have been found only in upper zone wells. A potentiometric surface map generated during the
May 2003 groundwater sampling suggests a shallow zone hydraulic gradient for the site of approximately
0.003 feet per foot directing ground water flow to the west. In the area of the landfill and wetlands, the
flow direction has a southerly component. The average hydraulic conductivity is reported to be 215 feet
per day. Using an average porosity of 0.30 results in a groundwater velocity of about 800 feet per year.
1.5.4
RECEPTORS
The primary potential receptors are residential water supply wells. Residential well and monitoring well
sampling from the RI indicated impacts as far as 3,800 feet southwest of the landfill. A water line was
extended to provide water to about 95 residences, including about 10 that had VOCs detected in their
wells. Residential wells are still in use downgradient of the landfill, outside of the plume area. Well and
surface water sampling indicates that VOCs did not reach Juday Creek.
1.5.5
DESCRIPTION OF GROUND WATER PLUME
In May 2003, the following wells had contamination exceeding the proposed remediation goals (PRGs).
Well
MW-6S
MW-3S
MW-4S
MW-10S
MW-13I
MW-13S
Contaminant Exceeding
Standard
Arsenic
1,2- Dichloroethane
Benzene
Arsenic
Arsenic
Arsenic
Arsenic
Arsenic
May 2003
Concentration (ug/L)
29
10
4.4
15
4.3
5
2.1
2.1
PRG (ug/L)
2
1
2.8
2
2
2
2
2
Note: The extraction wells were not sampled in May 2003.
Figure 1-3 presents the extent of arsenic above PRGs based on the May 2003 sampling event. The most
significant arsenic impacts are at MW-3S (15 ug/L), which is located less than 100 feet downgradient of
the landfill, and MW-6S (29 ug/L), which is located less than 500 feet downgradient of the landfill. The
arsenic impacts at MW-6S and MW-3S are relatively stable, and the other arsenic impacts are above the
PRGs but are below 5 ug/L (the MCL is 10 ug/L).
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In addition to the VOCs listed in the above table, tetrachloroethene (PCE) was detected at 35 ug/1 in MW-
1 IS (May 2003) and TCE was detected at 7.5 ug/L at EXT-5 (last sampled December 2000). Although
there is no PRO for PCE, the US EPA MCL for PCE is 5 ug/1. The PRO for TCE is 5 ug/1 (equal to the
US EPA MCL). Both the PCE and TCE impacts may be from an off-site source. The PCE
concentrations at MW-1 IS, which is located approximately 1,250 feet west (side-gradient) of the north
boundary of the landfill, have gradually decreased since 2000.
Figure 1-4 presents the monitoring locations where VOCs were above PRGs and/or MCLs based on the
May 2003 sampling event. VOC concentrations have remained relatively stable at MW-6S. Historical
sampling of monitoring wells indicates a significant decrease in VOC concentrations in MW-3S, which
previously had the highest concentrations found at the site. Total VOC concentrations (not including
tetrahydrofuran) have decreased from 61.6 ug/1 in November 1999 and 128 ug/1 in November 2000 to 4.2
ug/1 in May 2003.
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2.0 SYSTEM DESCRIPTION
2.1
SYSTEM OVERVIEW
The original alternative selected in the ROD included extraction from five wells (EXT-1 through EXT-5)
at a combined rate of 830 gallons per minute. The actual extraction rate from the system was about 300
gpm in 2003. The extraction has been focused on EXT-1 and EXT-2 (about 150 gpm combined)
immediately downgradient of the historical landfill contaminant source and EXT-5 (about 150 gpm)
downgradient in the area of the former residential well impacts. Wells EXT-3 and EXT-4 are located
downgradient of the site reinfiltration basin and were located there to potentially intercept infiltrated
water if treatment was not sufficient. Pumping from these two wells has since been determined to be
unnecessary since the infiltrating water and groundwater in the wells meets cleanup criteria.
The treatment system consists of two parallel lined constructed wetland cells followed by a lined
constructed wetlands polishing cell. The combined wetland area is 8.8 acres. The treated water is
discharged to a reinfiltration basin adjacent to the polishing cell and a vegetated "filter strip" adjacent to
Juday Creek. These features are indicated on Figure 1-2. Emergency discharge to the City of Mishawaka
POTW is available if it is ever needed. The reinfiltration basin was designed to be 1.8 acres but was
constructed at about one half that size. The discharge of treated groundwater, precipitation, and surface
water runoff to the filter strip is limited to 225 gpm, and the remaining water is infiltrated. The system is
automated to prevent high levels in the cells by shutting off extraction wells. This typically occurs during
heavy precipitation events.
The monthly sampling of the combined extraction system influent from January to September 2003
showed only one detection in the influent above the effluent criteria (arsenic at 5.2 ug/1 in May 2003).
TCE was detected in three samples at 1 to 1.5 ug/1, arsenic was detected in all 9 samples at 2.1 to 5.2 ug/1,
and toluene was detected in three samples at 1 to 2.4 ug/1. TCE has not been detected in any monitoring
well since 2000 but was found in EXT-5 at 4 ug/1 and EXT-2 at 1.4 ug/1 in 2002. The following table
summarizes the contaminant concentrations in the plant influent for 2003. The maximum 2003 influent
concentration and the effluent standards are provided.
Parameter
Arsenic
Lead
Chloroethane
Vinyl Chloride
Trichloroethene
1,2 Dichloroethane
Benzene
1,1 Dichloroethane
Toluene
Maximum 2003 Influent
Concentration
(ug/L)
5.2
<3.0
1.1
not reported
1.5
<1.0
<0.5
<1.0
2.4
Effluent Standard
(ug/L)
5.0
Not listed
No limit
2.0
5.0
5.0
5.0
90.0
Not listed
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Given these low influent concentrations and an extraction rate of 300 gpm, the maximum mass loading to
the treatment system is about 0.02 pounds of VOCs per day and about 0.02 pounds of arsenic per day. In
comparison the landfill gas extraction system has removed about 0.4 pounds of VOCs (-75% toluene) per
day since it was activated in October 2002.
2.2 EXTRACTION SYSTEM AND INJECTION SYSTEM
The current extraction system includes EXT-1 (also referred to as EXT-1A, EW -1, EXT-01), near MW-
6S about 400 feet downgradient of both the capped landfill and MW-3S. EXT-2 is about 350 feet directly
south of EXT-1. EXT-3 and EXT-4 are located along the same north-south axis at the south end of the
reinfiltration basin. EXT-5 is about 3,600 feet downgradient of the landfill, southwest of the middle of
the capped landfill. Each well is 10 inches in diameter and about 55 feet deep with 22 to 27 feet of
stainless steel screen. The wells are outfitted with 7.5 to 15 HP pumps, and the wellheads are completed
in 3 foot square underground vaults. Flow control valves are used to maintain continuous flow from the
well pumps. An HDPE header pipe connects the wells and runs to the head of the wetland cells. Two
control panels with separate autodialers are utilized: one for EXT-5 and one for the other wells. The
panels have controls for each pump and flow rate readouts from the pumps and outfall.
2.3 TREATMENT SYSTEM
The constructed wetlands system consists of 8.8 acres of wetlands in three cells. Cells 1 and 2 are parallel
primary treatment cells each handling half of the extracted flow. Cell 3 is a polishing cell for the effluent
of both cells. The wetland system was designed with consideration for precipitation for a hydraulic
residence time (HRT) of 4 days assuming a 2-foot operating depth. The actual HRT in 2003 has ranged
from 5 to 18 days due to the lesser groundwater extraction rates in comparison to the design. The system
design (Interim Remedial Action Report; September 2000) estimated a VOC and arsenic removal rate of
about 15%, and all estimated influent concentrations during design, except vinyl chloride (2.1 ug/1 versus
2.0 ug/1), were below the proposed discharge limits. Both vinyl chloride and arsenic estimated influent
and effluent concentrations were above the proposed remediation goals (PRGs).
The actual VOC removal rate in 2003 is difficult to estimate since TCE was the only VOC detected and it
was detected in the influent in only 3 out of 9 months, but the VOC removal rate appears to be over 30%,
and the arsenic removal rate in 2003 has been about 40%. Influent and effluent concentrations have been
below the discharge limits since operation began except for the influent in May 2003, but both the
influent and effluent have typically been above the PRGs.
The reinfiltration basin allows about 100 gpm of treated water back into the aquifer. This is significantly
less than the design rate (reported to be 6 inches per hour, which translates to more than 2,000 gpm for
0.9 acres) . The low reinfiltration rate, combined with the Juday Creek surface water discharge flow
maximum, limits the extraction well operation. The volume reinfiltrating has been limited due to
sediment buildup and algae growth. Annual dredging of the basin is conducted to maintain the infiltrating
capacity, but even with corrective action the infiltration rate is an issue, particularly when precipitation
generates significant runoff.
The landfill gas collection system consists of a 1 horsepower blower and a knockout tank. The collected
gas is discharged directly to the atmosphere at a rate of about 90 scfm. The methane content of the vapor
in 2003 has been 2.6% to 3.5 %. The total VOC concentrations have ranged from 25,750 ug/m3 to 54,650
ug/m3. Toluene has been 67% to 74% of the total VOCs. Other VOCs, including 1,1,1 TCA; 1,1 DCA;
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benzene; chloroethane; cis-l,2-DCE; ethylbenzene; methylene chloride; xylenes; TCE; and vinyl chloride
have been detected in the vapor in 2003.
2.4 MONITORING PROGRAM
All 33 current site monitoring wells (16 shallow, 15 intermediate, and 2 deep) are sampled semi-annually
(future monitoring well sampling will be on an annual schedule). The combined system influent and
effluent is sampled monthly. Individual extraction wells were sampled annually from 1999 to 2002.
Monitoring wells are sampled by purging three well volumes with dedicated pneumatic QED sampling
pumps then collecting VOC samples at a low flow rate directly from discharge tubing and dissolved
metals samples through an inline field filter. Extraction wells are purged for about 5 minutes of pumping
and samples are taken without field filtering Analysis is conducted for VOCs, arsenic, and lead. The
resulting data are presented in a semi-annual groundwater monitoring report. A detailed surface water,
sediment, and aquatic biota sampling is conducted annually in Juday Creek. QA/QC Level IV protocol is
used for sample analysis. The results of these sampling programs are presented in annual Long-Term
Remedial Action Reports.
The 18 landfill gas monitoring stations and the landfill gas collection system effluent vapor are checked
for methane concentrations on a quarterly schedule, and the collection system vapor is also analyzed for
VOCs.
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3.1
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE
CRITERIA
CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
There are two RODs for the site, and a waterline extension was completed as a time critical emergency
removal action. Components for the RODs for each operable unit are as follows:
OU1 (July 13, 1995) - installation of a composite barrier cap, collection of landfill gas, surface water
drainage, and groundwater monitoring
OU2 (May 3, 1996) - groundwater extraction for containment, groundwater treatment by artificial
wetlands, discharge, and monitoring
The OU2 ROD states that the objective of the action is to remediate contaminated groundwater, both on-
site and off-site. Groundwater remediation would be expected in 20 to 60 years of operation.
The proposed remedial goals (PRGs) for the primary contaminants of concern that remain at the site as of
the RSE are summarized in the following table.
Contaminant Exceeding Standard
Arsenic
Chloroethane
Vinyl Chloride
1 ,2-Dichloroethane
Benzene
Trichloroethene
1 , 1 -Dichloroethane
Proposed Remedial Goal (ug/L)
2
2,085,700
1
1
2.8
5
3,530
Iron was included as a contaminant of concern in the ROD with a PRG of 380 ug/1; however, it was
subsequently dropped due to its ubiquity in the area. Lead is not included as a contaminant of concern
but lead concentrations are monitored. Tetrachloroethene (PCE) is not included as a contaminant of
concern even though MW-1 IS has had PCE concentrations consistently above the MCLs. The exclusion
of PCE from the contaminants of concern is probably because the PCE is likely from an upgradient, off-
site source.
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3.2
TREATMENT PLANT OPERATION STANDARDS
The effluent standards for the constituents of concern for discharge to Juday Creek are provided in the
following table. The effluent standards for the infiltration basin are presumably the PRGs presented
above.
Parameter
Arsenic
Chloroethane
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
Benzene
Trichloroethene
Lead
Vinyl chloride
Effluent Standard
(ug/L)
5
No limit
90.0
5.0
5.0
5.0
Not listed
2.0
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4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT
4.1 FINDINGS
The RSE team observed a site where the landfill capping and landfill gas collection remedies have been
implemented, and a groundwater extraction and treatment system has been operating for 3 years. Ground
water concentrations that were relatively low initially, have decreased substantially, indicating the initial
success of the remedies. The ground water concentrations observed in monitoring wells and the treatment
system influent indicate minimal remaining groundwater impacts at the site. The site team is beginning to
consider what operations indicators or time frame should be considered for suspending and terminating
active remediation. The observations provided below are not intended to imply a deficiency in the work
of the system designers, system operators, or site managers but are offered as constructive suggestions in
the best interest of the EPA and the public. These observations obviously have the benefit of being
formulated based upon operational data unavailable to the original designers. Furthermore, it is likely
that site conditions and general knowledge of ground water remediation have changed overtime.
4.2 SUBSURFACE PERFORMANCE AND RESPONSE
4.2.1 WATER LEVELS
Depth to water measurements are collected semi-annually, these measurements are converted into water
elevations and presented in the semiannual reports. The potentiometric maps do not indicate a capture
zone associated with the extraction wells; however, the location of the monitoring wells and water level
measurements is not conducive to determination of capture.
4.2.2 CAPTURE ZONES
The Five Year Review (September 11, 2002) states that groundwater is being contained at the site. It was
reported that groundwater modeling had been done, but the RSE team did not review any documents that
indicated that containment was feasible at the actual groundwater extraction rates, which are less than
40% of the design values.
A water budget analysis as shown below provides an indication of containment effectiveness. A water
budget analysis calculates the amount of ground water entering the site from upgradient and compares
this value to the amount extracted. In general, the amount extracted should exceed the amount entering
from up gradient by a factor of 1.5 or 2.0 for effective capture. As stated in Section 1.5.3 of this report,
the hydraulic gradient is approximately 0.003 feet per foot and the hydraulic conductivity estimated at
approximately 215 feet per day. This translates to a Darcy velocity of 0.65 feet per day. The saturated
thickness from the water table to the bottom of the upper zone is approximately 30 feet, and a
representative width of contamination is approximately 700 feet (i.e., from MW-6S south of EXT-2). This
yields a total cross-sectional area of approximately 21,000 square feet (30 feet deep by 700 feet across) to
contain. Therefore, approximately 13,700 cubic feet per day (0.65 feet per day times 21,000 square feet)
enter the site from upgradient during non-pumping conditions. This is equivalent to approximately
102,000 gallons per day. The pumping rate from EXT-1 and EXT-2 is approximately 150 gpm combined
(approximately 216,000 gallons per day), so the amount of ground water extracted from EXT-1 and EXT-
2 is approximately a factor of 2 times greater than the amount of ground water flowing through that
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portion of the site based on the reported hydraulic data. A water budget analysis, therefore, supports that
capture is provided.
An evaluation of water quality data from monitoring wells downgradient of the expected capture zone is
inconclusive for determining capture zone effectiveness because a VOC plume was never clearly
delineated by monitoring wells. However, the TCE concentrations at downgradient extraction well EXT-
5 and the combined system influent have decreased since full-scale pumping began in October 2000. The
TCE concentration at EXT-5 was 7.5 ug/1 in November 2000 and 4 ug/1 in December 2002. The
combined influent TCE concentrations were 4.7 ug/1 to 6.3 ug/1 in the first three months of operation and
have been below 1 ug/1 for the past five months (May to September 2003). This again supports that
capture is provided.
4.2.3
CONTAMINANT LEVELS
Ground water contamination at the site has decreased substantially since the RI. The RSE team attributes
this decrease to a productive aquifer augmented by the recent groundwater extraction. The following
table provides maximum ground water concentrations prior to remediation (i.e., from the 1994 RI and
other sampling prior to full-scale groundwater extraction in October 2000) and the maximum
concentrations from the May 2003 sampling event.
Contaminant Exceeding
Standard
Maximum
Pre-Remediation
Concentration(ug/L)
Maximum May 2003
Concentration
(ug/L)
Chloroethane
1 ,2-Dichloroethane
1 , 1 -Dichloroethane
Tetrahydrofuran
Tetrachloroethene (PCE)
Trichloroethene (TCE)
Benzene
91 (MW-3)
16 (MW-3)
8.3 (MW-3)
15,000 (MW-3)
110(MW-11S)
7.5 (EXT-5)
55 (MW-3)
39 (MW-6S)
10 (MW-6S)
<1
<2
35(MW-11S)
<1
4.4 (MW-6S)
Arsenic
35 (MW-3S)
29 (MW-6S)
As is evident from the table, most contaminant concentrations have decreased significantly. They are,
however, not low enough to meet the cleanup standards at all wells (see Section 1.5.6) and conditions
have been nearly stable for the past three sampling events since May 2002.
The site-related contaminantion found in MW-3S (and MW-6S) appears to be limited to the source area
and the area immediately downgradient of the source area because the wells further downgradient
between the source area and EXT-5 (MW-9S,-9I,-10S, and -101) do not have (and have not recently had)
significant impacts.
TCE is the main contaminant of concern detected in downgradient well EXT-5. TCE is not detected in
EXT-1 and is less than 2 ug/1 in EXT-2 so it is unclear if the containment provided at the landfill by these
2 wells helps reduce downgradient TCE concentrations. Therefore, the TCE impacts found in
groundwater extracted from EXT-5 could be from an unidentified source possibly south of the site.
Because concentrations at EXT-5 are decreasing, any additional TCE source is likely minimal.
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PCE is not a constituent of concern, and the PCE contamination in MW-1 IS appears to be from an off-
site source. MW-1 IS is side-gradient of the landfill and the chemical signature at MW-1 IS very different
from the other site wells. None of the other site wells have or have had detectable PCE concentrations,
and MW-1 IS has undetectable concentrations of other site-related contaminants. These impacts are
outside of the extraction well capture zones and appear to be decreasing with time. The site team intends
to allow these concentrations to further attenuate without remedial action.
4.3 COMPONENT PERFORMANCE
4.3.1 EXTRACTION SYSTEM WELLS, PUMPS, AND HEADER
The extraction wells continue to operate effectively. Pumping has appropriately been focused on EXT-1
(October 2002-2003 average rate of about 50 gpm), EXT-2 (about 79 gpm) and EXT-5 (about 132 gpm).
Pumping at EXT-3 and EXT-4 has averaged less than 20 gpm each. Pumping rates are limited by the
infiltration basin capacity but the extraction rate appears to be sufficient for containment of groundwater
under the northern portion of the landfill where historical impacts were found. Pumping at EXT-5
captures groundwater from an extensive downgradient area. There were no problems reported with the
pumps or PVC and HDPE piping.
4.3.2 CONSTRUCTED WETLAND
The 8.8 -acre constructed wetlands are operating at less than 50% of the design capacity. The system has
a capacity of about 4.3 million gallons at a 2-foot operating depth. The design hydraulic residence time
of 4 days accommodates over 650 gpm of influent (about 4.5 inches/day hydraulic loading rate). The
system has operated in 2003 with monthly hydraulic loading rates ranging between 1.0 to 3.9 inches per
day with an average of 2.04 inches per day. The treatment efficiency for VOC and arsenic removal,
which is greater than 30% and about 40% respectively, has been higher than the design of 15%. The
influent to the system has been below the effluent standards for all but one month (arsenic at 5.2 ug/1
versus the 5.0 ug/1 standard in May) in 2003, so that typically no treatment is required. An algae growth
problem has been addressed by the application of barley straw.
4.3.3 REINFILTRATION BASIN
The reinfiltration basin has been the limiting process in the extraction/treatment/discharge system. The
basin was constructed smaller than originally designed due to property availability and has had algae and
sediment fouling problems. The basin has allowed a groundwater outflow of about 80 gpm in 2002 and
116 gpm in 2003, which is reduced from the initial 2001 rate of about 230 gpm. Dredging and
mechanical scraping of the basin floor has been used to maintain capacity. With the additional Juday
Creek discharge capacity, the available extraction rate has likely been sufficient for hydraulic containment
of the northern portion of the site.
4.3.4 JUDAY CREEK DISCHARGE
The allowable discharge rate to the filter strip adjacent to Juday creek is 225 gpm. The approximately
500-foot long by 60-foot wide filter strip contains 5 perforated drains in a vegetated, bermed area. The
city is maintaining the filter strip as part of the agreement with the site team. Annual sampling and
studies have not indicated impacts from the Douglas Road site from the filter strip discharge.
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4.3.5
CAP AND LFG SYSTEM
The landfill cap has minimized leaching of contaminant from the landfill and allowed the landfill gas
extraction system to effectively remove VOC mass from the landfill. The landfill gas system, consisting
of 15 extraction points and a 1 HP blower discharging about 90 cfm, has recovered over 20 times more
VOC mass than the groundwater extraction system in the year that it has been in operation. In addition
the landfill gas system has successfully alleviated a gas migration issue. The state will be taking over cap
and landfill gas system maintenance by the end of 2003.
4.3.6
SYSTEM CONTROLS
The system has high level alarms, flow meters and pump on/off controls at two separate panel locations
(at EXT-5 and a location near the site for the other four extraction wells) that the plant operator can
monitor to determine and adjust system parameters. These control panels each have an autodialer to
contact the operator during off hours.
4.4
COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
O&M COSTS
The budgeted annual costs for system O&M are approximately $177,800 per year for 2004. This is
reduced from about $200,000 per year in 2002 and 2003 due to the planned reduction from semi-annual
to annual groundwater monitoring frequency. A breakdown of the budget costs is provided in the
following table and subsections based on information provided by the contractor project manager during
the RSE site visit. It should be noted that this annual cost exceeds the ROD estimate of $86,000 by more
than 100% but appear appropriate relative to other Fund-lead P&T systems.
Item Description
Labor: Project management, technical support, reporting
Labor: Groundwater and Juday Creek sampling
Labor: Plant operator, process sampling
Analytical: Monitoring wells
Analytical: Process
Analytical: Juday Creek
Utilities: Electricity
Infiltration Basin Maintenance/Dredging
Total Estimated Cost
Estimated Cost
$41,300 per year
$28,700 per year
$45,800 per year
$8,300 per year
$9,300 per year
$20,200 per year
$16,700 per year
$7,500 per year
$177,800
% of Total Cost
23%
16%
26%
5%
5%
11%
9%
4%
4.4.1
UTILITIES
At any given time, the treatment system has approximately 30 HP of pumps operating. The contractor
project manager indicated that utilities cost approximately $16,700 per year, which is consistent with a
unit electrical cost of approximately $0.06 per kWh.
4.4.2
INFILTRATION BASIN MAINTENANCE
Regular annual dredging of the infiltration basin has been necessary to remove sediment and algae to
maintain infiltration flow. The cost per dredging event is $7,500.
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4.4.3 LABOR
Labor is the largest component of annual costs, contributing over 65% of the costs. The plant operator
works part time checking the system at least 3 times per week. This totals less than 20 hours per week
including responding to alarm calls. System operating labor is budgeted at a reported cost of $45,800 per
year. With respect to project management, technical support, and reporting, a reported cost of $41,300
per year and an estimated hourly rate of $100 per hour, including overhead, should translate to
approximately 413 hours per year, or approximately 8 hours in a 40-hour week. The cost for sampling
labor of $28,700 per year includes annual sampling of the 33 monitoring wells, 3 surface water and
sediment locations, and fish tissue. In addition, habitat and aquatic community assessments are
completed.
4.4.4 CHEMICAL ANALYSIS
The budget for analytical costs in 2004 is about $37,800. This expense has recently been reduced by
reducing the monitoring well sampling frequency and obtaining updated laboratory prices. Monitoring
well analysis costs are budgeted at $8,300 for analysis of 33 well samples plus QA/QC samples for
VOCs, arsenic, and lead. Process analysis includes a total of 24 system influent and effluent samples plus
QA/QC samples for the same parameters as the monitoring wells at a cost of $9,300 per year. Juday
Creek surface water, sediment, and fish tissue sample analysis includes a wide range of parameters and
extensive QA/QC analysis at a cost of about $20,200 per year. The Juday Creek sampling program is
considered to be excessive by the site team, but it was a condition desired by the public to obtain the
surface water discharge permit. The Level IV QA/QC protocol used for sampling analysis accounts for
over 25% of the analytical costs. For long-term system O&M Level IV QA/QC is not required at many
Superfund Sites and the RSE team could not identify any reasons why it should be continued at Douglas
Road.
4.5 RECURRING PROBLEMS OR ISSUES
The contractor reports the following recurring problems.
Algae Growth: This was a problem in both the constructed wetlands and the infiltration basin. As
the wetland vegetation has become established the algae has been less of a concern.
Development of an algae mat on the floor of the infiltration basin has continued to be an issue
limiting the basin capacity. The use of barley straw to reduce algae in late 2002 and 2003 has
helped the problem; however, annual dredging of the basin is still planned.
Stormwater Run-off: With the infiltration basin infiltrating capacity limited (in part due to algae
growth) to about 100 gpm from an initial capacity of about 250 gpm and a higher design capacity,
the available infiltrating rate controls the amount of groundwater that can be extracted. In periods
of heavy precipitation, groundwater extraction must be reduced or suspended.
4.6 REGULATORY COMPLIANCE
The treatment system has consistently met effluent standards and stayed within the maximum discharge
flow limit.
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4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL
CONTAMINANT/REAGENT RELEASES
No reagent releases or accidents were reported to the RSE team.
4.8 SAFETY RECORD
No reagent releases or accidents were reported to the RSE team.
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
The ROD indicates that at the time of the risk assessment, carcinogenic risk associated with exposure of a
hypothetical adult resident to contaminated groundwater at the site was as high as 3.8* 10~3 due to bis(2-
ethyl hexyl phthalate, arsenic, dibenzo (a,h) anthracene, vinyl chloride and indeno(l,2,3-c,d) pyrene.
Carcinogenic risk due to off-site exposure was as high as 3.2x 10~4 due to vinyl chloride, arsenic, and
TCE. Of these compounds only arsenic, TCE, and vinyl chloride are considered site contaminants of
concern. In the most recent groundwater sampling event only arsenic (MW-3S, MW-4S, and MW-6S)
and 1,2-Dichloroethane (MW-6S) were found at levels above proposed remediation goals.
It appears that the remedy has largely been protective with respect to site-related contamination. Based
on the limited hydraulic information available, it appears that the capture zone is likely sufficient to
prevent further migration of site-related contamination. Site-related contamination may have been able
to migrate off site prior to initiation of groundwater extraction. This migration may be combined with
migration from unidentified off-site contaminant sources including that indicated by PCE impacts at MW-
1 IS. The remedy, in its current form, is incapable of providing complete capture of the contamination at
MW-11S.
It is beyond the scope of the RSE to evaluate the current risks associated with the site. However, it
appears that risks have been reduced. The site has been capped and fenced, city water line was extended
to impacted and neighboring residences, and contaminant concentrations have decreased in monitoring
wells and extraction wells over time. Residential wells, however, are still in use downgradient of EXT-5
and may be potentially at risk if plume capture is interrupted or is not sufficient.
5.2 SURFACE WATER
The closest downgradient surface water is Juday Creek, located approximately 1,600 feet south of the
site. Impacts to Juday Creek have not been identified.
5.3 AIR
The primary route for impacts to the air is from the landfill gas system off-gas. The VOC levels are well
below the threshold requiring vapor controls. Site wells do not indicate elevated levels of ground water
contamination. Therefore, VOC vapor intrusion in this area is not likely an issue requiring attention. The
landfill gas collection system has been effective in preventing gas migration to the east of the site
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5.4 SOILS
The soil contamination associated with the site has been capped with a composite barrier and fenced. No
further protectiveness issues related to soil are expected.
5.5 WETLANDS AND SEDIMENTS
Sediments sampling in Juday Creek has not indicated any impacts from the site. The main treatment
component at the site is lined constructed wetlands.
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6.0 RECOMMENDATIONS
Cost estimates provided herein have levels of certainty comparable to those done for CERCLA Feasibility
Studies (-307+50%), and these cost estimates have been prepared in a manner consistent with EPA 540-R-
00-002, A Guide to Developing and Documenting Cost Estimates During the Feasibility Study, July 2000.
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS
6.1.1 SAMPLE EXTRACTION WELLS ANNUALLY
The extraction wells were sampled annually from 1999 to 2002, but not in 2003. Analysis of
groundwater from individual extraction wells provides a good indication of contaminant levels in the
general area of the well. For example EXT-5 had TCE concentrations of 7.5 ug/1 in 2000 and 4.0 ug/1 in
2002. Sampling of EXT-5 on a regular basis would determine if TCE concentrations continue to decline
and remain below PRGs. Sampling of EXT-1 and EXT-2, the focus of on-site containment efforts, will
also be useful to determine the trends of contaminants of concern. This sampling should be considered
part of the effort to develop an exit strategy. Sampling of the 5 extraction wells on an annual basis is
recommended and should require less than $1,500 per year. The RPM indicates that these wells will be
sampled in Spring 2004.
6.1.2 INVESTIGATE OFF-SITE SOURCES AND REMAINING DOWNGRADIENT IMPACTS
Based on the ROD, PCE is not a contaminant of concern at the site but it is present at MW-1 IS at
concentrations consistently above the MCL, unlike any other VOC at the site. PCE has not been detected
at any other monitoring well at the site or in landfill gas analysis. The site team recognizes that MW-1 IS
is outside of the capture zones of the system extraction wells and plans no active remediation in the area.
The PCE impact in MW-1 IS is very likely from an unidentified source north of the site. The RSE team is
concerned that the unidentified source could present a greater human health risk than the Douglas Road
landfill impacted groundwater at this time. Although investigation of the potential source and delineation
of impacts is likely beyond the defined scope of the EPA effort at Douglas Road, we recommend a
groundwater investigation with direct-push sampling be conducted to characterize the level and extent of
PCE impacts in this area. Conceptually, the investigation would be initiated with a historical map review
and site walk to determine if any former dry cleaners or other solvent use facilities were/are present
within one mile upgradient of MW-1 IS. Based on the initial findings, shallow groundwater samples
would be taken with a geoprobe at accessible locations northeast of MW-1 IS and near any potential
downgradient receptor. About 5 to 10 shallow samples would be taken for VOC analysis, so the expense
of the effort would be relatively low.
The extent and level of TCE remaining in the area around EXT-5 is not well understood and the TCE
(and to a lesser extent vinyl chloride) impacts at EXT-5, MW-14S, MW-15S, MW-16S and former
residential wells in the area do not show a clear connection (in current or 1994 plume maps) to
groundwater impacts near the landfill. TCE is present in the landfill gas and the landfill may well have
been the source of the downgradient TCE impacts, but cometabolism of TCE near the source area may
have removed the TCE from ground water. The RSE team recommends groundwater samples be taken
with a direct-push methods along Douglas Road east of EXT-5 and also north and west of EXT-5.
Another 5 to 10 shallow samples would be taken for VOC analysis. At a minimum this sampling would
indicate the extent and degree of the remaining TCE impacts in this area.
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The investigation in these two areas will provide information to the site team that will improve the site
conceptual model and allow better consideration of a site exit strategy. The combined investigation,
including developing a work plan and producing a report should be completed for less than $50,000.
6.2 RECOMMENDATIONS TO REDUCE COSTS
6.2.1 REDUCE ANALYTICAL QA/QC REQUIREMENTS
At least 25% of the site analytical program cost is due to the intensive Level IV QA/QC protocol. With
considerable long-term data available there is no apparent need to exceed Level II standards. Reducing
the QA/QC level will save about $10,000 per year. Many Superfund sites in long-term O&M stages do
not perform the rigorous QA/QC found at this site.
6.2.2 CONSIDER CONVERTING THE WETLAND POLISHING CELL TO AN INFILTRATION BASIN
Discharge to Juday Creek requires an expensive annual sampling and evaluation program, and
alternatives should be considered. If the existing treatment system were to continue operation at the
present rate (extraction potentially over 300 gpm), additional infiltration capacity would be necessary to
eliminate the need for surface water discharge to Juday Creek. The existing polishing cell of the
treatment system is not needed to meet effluent standards (no treatment at all is typically required). The
current polishing cell, at 1.8 acres, could provide over 200 gpm of additional infiltrating capacity based
on the performance of the current basin. To convert the cell to an infiltration basin the liner and sediment
would require removal and disposal and piping modifications would be necessary. Based on the cost of
dredging the existing basin, converting this cell to an infiltration basin should require $100,000 or less. If
the Juday Creek sampling program could be eliminated, approximately $30,000 per year might be saved.
Therefore, this recommendation appears cost-effective if the remedy is expected to operate for three more
years at an extraction rate greater than the capacity of the infiltration basin. If operation is expected for a
number of years, but extraction can be reduced below the capacity of the infiltration basin, then discharge
to Juday Creek (and the associated costs) could likely be eliminated without any capital expenditures.
Implementation of this recommendation should be delayed until the recommendations in Section 6.4.1 are
considered.
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT
No specific recommendations are provided in this category. Rather, the site team is encouraged to focus
on the recommendations in the other categories.
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT
6.4.1 DEVELOP AN EXIT STRATEGY
Although the remedy has not yet achieved its specific objectives (i.e., restoration to applicable standards),
the risks that originally required active remediation are no longer present. It may therefore be appropriate
to discontinue the P&T system now or in the near future and rely on other mechanisms to reach the
cleanup goals. The RSE team suggests the following potential approaches that could be adopted as the
basis for the remedy exit strategy.
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Option 1: Continue operating the P&T system until all contaminants of concern are at or below
background concentrations
Given that arsenic concentrations have not substantially decreased over the past four to five years in MW-
6S with the current P&T system, this approach will likely take many years to be successful, and might not
ever be successful. This approach would provide continued capture at the landfill with EXT-1 and EXT-
2. Downgradient groundwater extraction at EXT-5 could likely be terminated, especially if the
contamination in and around EXT-5 remains below PRGs as it currently is. The sampling recommended
in Section 6.1.2 might further confirm that concentrations near EXT-5 are sufficiently low to discontinue
pumping from this location. This approach would likely eliminate the need for discharge to Juday Creek
and would therefore reduce annual operating costs to below $150,000 if the Juday Creek sampling
program could be discontinued.
Option 2: Discontinue the P&T system to determine if contamination will migrate offsite above specified
concentration criteria
Under this approach, the site managers would discontinue the P&T system but would continue monitoring
to verify that the remaining, relatively low-level contamination does not migrate offsite at concentrations
that would be of concern. Elevated arsenic levels had not migrated off the site at concentrations of
concern prior to P&T operation, and it is highly unlikely that elevated concentrations would migrate off
site if the system were shut down. No VOCs are consistently above PRGs in any monitoring or extraction
well. Various VOCs (benzene, 1,2 DCA, and vinyl chloride) have periodically exceeded PRGs in 3
monitoring wells (MW-3S, MW-6S, and MW-13S) since 1999. These exceedances are at relatively
random levels near the PRG values and do not represent a definable plume. To proceed with shutting
down the system, the site team should develop a set of criteria that, if exceeded when the system is shut
down, would cause the P&T system to be restarted. The criteria should include sampling locations,
concentrations for each contaminant of concern at those locations, and the number of samples with
elevated concentrations that would be needed to justify restarting the P&T system.
The landfill gas system would continue to operate, and the site team would continue with its monitoring
program to 1) monitor for attainment of the cleanup criteria and 2) monitor for contaminant migration to
determine whether or not the P&T system should be restarted. Developing this exit strategy should cost
approximately $20,000, but annual O&M would likely consist only of monitoring, data analysis, and
reporting. The annual O&M cost could likely be under $75,000 per year.
6.5 SUGGESTED APPROACH TO IMPLEMENTATION
The RSE team suggests implementing recommendations 6.1.1 and 6.2.1, which would provide for more
comprehensive aquifer sampling while reducing annual O&M costs to approximately $170,000. The site
team should then focus on the exit strategy as described in Section 6.4.1. The investigation discussed in
Section 6.1.2 may be necessary to determine how to implement the exit strategy and provide verification
that it is appropriate.
With respect to recommendation 6.4.1, the RSE team suggests proceeding with the second option:
discontinuing the P&T system, monitoring the potential for plume migration, and restarting the system if
migration occurs at unacceptable levels. The RSE team further suggests adopting the selected exit
strategy and approach by the end of calendar year 2004. If the P&T system is not discontinued, then
recommendation 6.2.1 should be considered.
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7.0 SUMMARY
The RSE team observed a site where the soil remedy had effectively contained soil contamination and
landfill gas collection is removing source area mass, which had been providing a continuing source of
dissolved ground water contamination. Ground water concentrations have decreased substantially,
indicating the initial success of the remedies. The ground water remedy has continued to extract and treat
contaminated ground water in an attempt to achieve its remediation objectives. The observations provided
below are not intended to imply a deficiency in the work of the system designers, system operators, or site
managers but are offered as constructive suggestions in the best interest of the EPA and the public. These
observations obviously have the benefit of being formulated based upon operational data unavailable to
the original designers. Furthermore, it is likely that site conditions and general knowledge of ground
water remediation have changed overtime.
Recommendations to improve effectiveness in protecting human health and the environment include
sampling extraction well influent on an annual basis as well as investigating the potential for off-site
sources and the extent of remaining site impacts. Recommendations to reduce costs include reducing
analytical QA/QC requirements and potentially converting an unnecessary treatment system component
into an infiltration basin so that discharge to Juday Creek (and possibly the expensive Juday Creek
sampling program) can be terminated. No recommendations are provided for technical improvement.
Instead, emphasis should be placed on implementing the other recommendations. For site closeout, the
RSE team recommends developing an exit strategy and provides two potential approaches for
consideration. The risks that the ROD indicates as the reason for active remediation are no longer
present. Therefore, the recommended approach includes discontinuing the P&T system and monitoring
for potential plume migration.
Table 7-1 summarizes the costs and cost savings associated with each recommendation in Sections 6.1
through 6.4. Both capital and annual costs are presented. Also presented is the expected change in life-
cycle costs over a 30-year period for each recommendation both with discounting (i.e., net present value)
and without it.
22
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Table 7-1. Cost Summary Table
Recommendation
6. 1. 1 Sample Extraction Wells
Annually
6.1.2 Investigate Off-Site
Sources and Remaining
Downgradient Impacts
6.2.1 Reduce Analytical
QA/QC
6.2.2 Consider Converting
Cell 3 to an Additional
Infiltration Basin
6.4. 1 Develop and Exit
Strategy
Reason
Effectiveness
Effectiveness
Cost
Reduction
Cost
Reduction
Site Closeout
Additional
Capital
Costs
($)
$0
$50,000
$0
$100,000
$20,000
Estimated
Change in
Annual
Costs
($/yr)
$1,500
$0
($10,000)
($30,000)
$0
to
($95,000)3
Estimated
Change
In Life-cycle
Costs
(S)1
$15,000
$50,000
($100,000)
($200,000)
$0
to
($950,000)3
Estimated
Change
In Life-cycle
Costs
($)2
$12,000
$50,000
($81,000)
($143,000)
$20,000
to
($750,000)
Costs in parentheses imply cost reductions.
1 assumes 10 years of operation with a discount rate of 0% (i.e., no discounting)
2 assumes 10 years of operation with a discount rate of 5% and no discounting in the first year
3 this change in costs is in addition to any changes associated with 6.1.1 and 6.2.1
23
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FIGURES
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FIGURE 1-1. SITE LOCATION MAP.
-N-
0
2000
SCALE IN FEET
4000
QUADRANGLE
LOCATION
INDIANA
(Note: This figure is was developed from U.S.G.S. Quadrangle, South Bend East, IN (1992).
-------
FIGURE 1-2. GROUNDWATER MONITORING WELL AND EXTRACTION WELL LOCATIONS AND GROUNDWATER PIPING LAYOUT.
-N-
MW-11S *'X
T~r
MW-m,//7 i 1
// CONSTRUCTED ^^Jl
WETLANDS TĢ>-^
PRIMARY i ^ŧ
TREATMENT CELLS
MW-12SŪ//
//~\ MW-121 ,/7 MW-06S-.
X\ ''/ \9
\N
Nv, _ - - - EXT-1A/
\ \ '
' v \
i
i MW
! MW
'A
i
i
i
' .// EXT-2JIA
I! // MW-10S Ŧ
// MW-101 MW-U/b
// MWIUI MW-071
// MW 17S
ŪMW-17I REINFILTRATION -.
BASIN
EXT-3
$
i
i
j.
!
>tA
MW-9S MW-13SJ
MW-9I MW-131*!
f
t
i
, ^ EXT-5
MW-14S
MW-141
"Tj! j 1 ^--^ [MW-OIS
f ~~! MW-02S
' iMW-021
i
-03S|
-031 ]
* ! CAPPED
] LANDFILL
i
i
i
'MW-04S
lMW-041
JMW-04D
i
i
i
1
i
^^^ i
i ~~~ ^^
i ^^
i
i
T 1
i ' ^^i.
r [ ^~ Mw-011
H TI LMW-OID
S
r1
r1
h
^
j
r
^J
ppnnnDTY
BOUNDARY
CONSTRUCTED
WETLANDS
POLISHING
|A !ŧ _| CELL
Lw-o5s4 " ''
j MW-051 !|jj
^
TIE IN TO-1
MISHAWAKA
SANITARY
SEWER
0
60Q
SCALE IN FEET
12QO
Ū
A
LEGEND
MONITORING WELL
EXTRACTION WELL
GROUNDWATER PIPING
PROPERTY BOUNDARY
(Note: Figure based on one produced by CH2MHILL.)
-------
FIGURE 1-3. MONITORING LOCATIONS WHERE ARSENIC EXCEEDED PRGs IN MAY 2003.
i
' r^'i
!MW-05SLJ|1
! MW-05lC_J!j
w
600
SCALE IN FEET
1200
Q ARSENIC BELOW PRGs
O ARSENIC ABOVE PRG BUT BELOW
ARSENIC ABOVE BOTH PRG AND MCE
31 OE 10 ug/L
(Note: Figure based on one produced by CH2MHILL.)
NOTE: THE MAXIMUM ARSENIC CONCENTRATION.
IN MAY 2003 WAS 29 ug/L AT MW-6S.
MONITORING WELL
A EXTRACTION WELL
GROUNDWATER PIPING
PROPERTY BOUNDARY
-------
FIGURE 1-4. MONITORING LOCATIONS WHERE VOCs EXCEED PRGs AND/OR MCLs TN MAY 2003.
I
-N-
(Note: Figure based on one produced by CH2MHILL.)
MONITORING WELL WITH SITE-RELATED VOCs BELOW PRGs
MONITORING WELL WITH SITE-RELATED VOCs ABOVE PRGs
MONITORING WELL WITH PCE ABOVE MCE
EXTRACTION WELL WITH TCE ABOVE PRO (SAMPLED 12/20,00)
MOTE: PCE AT MW-11S AND TCE AT EXT-5
ARE LIKELY FROM AN OFF-SITE SOURCE,
MONITORING WELL
EXTRACTION WELL
GROUMDWATER PIPING
PROPERTY BOUNDARY
------- |