REMEDIATION SYSTEM EVALUATION
SHORCO SOUTH
MAHWAH, NEW JERSEY
Report of the Remediation System Evaluation
Site Visit Conducted
July 29, 2003
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Office of Solid Waste EPA 542-F-04-030
and Emergency Response September 2004
(5102G) www.epa.gov/tio
clu-in.org/optimization
Remediation System Evaluation
Shorco South
Mahwah, New Jersey
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NOTICE AND DISCLAIMER
The U.S. Environmental Protection Agency (U.S. EPA) funded the preparation of this document by
GeoTrans, Inc. under General Service Administration contract GS06T02BND0723 to S&K Technologies
Inc., Bremerton, Washington and under EPA contract 68-C-02-092 to Dynamac Corporation, Ada,
Oklahoma. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
This report has undergone review by the state site manager and EPA headquarters staff. For more
infomation about this project, contact: Joe Vescio (703-603-0003 or vescio.joseph@epa.gov) or Kathy
Yager (617-918-8362 oryager.kathleen@epa.gov).
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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 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. Note that the recommendations are based on an
independent evaluation by the RSE team, and represent the opinions of the RSE team. These
recommendations do not constitute requirements for future action, but rather are provided for the
consideration of all site stakeholders.
The Shorco South site is located on the southbound side of Route 17 in the Township of Mahwah, New
Jersey. The Shorco South site is downgradient of the Shorco North site, which also has ground water
impacted with petroleum constituents. This RSE focuses on the Shorco South site, and the Shorco North
site is discussed only in relation to its impact on Shorco South. The Shorco South site remediation is
currently being run by NJDEP under the publicly funded cleanup program, while the Shorco North
remediation is still being operated by the responsible party. Ground water flows in a south to southwest
direction across the Shorco South site, towards the Ramapo River.
Dissolved benzene, methyl tertiary butyl ether (MTBE), and tertiary butyl alcohol (TEA) levels are
present in many wells above ground water criteria and are good "indicator parameters" for continuing
impacts at the site. Toluene, ethylbenzene, xylene, and lead only sporadically exceed the criteria, and
occur at wells within the plumes associated with the three indicator parameters (benzene, MTBE, and
TEA). On-site wells located upgradient of on-site sources ("upgradient" wells) are impacted, but at
lower concentrations than the "mid-plume" wells. Impacts at these "upgradient wells" are most likely
due to Shorco North, and concentrations at these wells are decreasing over time. At the "mid-plume"
wells (impacted primarily by sources at Shorco South) the concentrations also appear to be decreasing
overtime, though in some cases concentrations still remain several orders of magnitude above cleanup
criteria. Trends at the "downgradient" wells are not as clear.
A ground water pump and treat system was completed during 1991 which included 6 recovery wells.
Nine well points were added to the system in 1996 to improve containment at the downgradient south
corner of the site. The well points were not effective due to iron fouling problems. In the June 10, 1997
"Evaluation of Existing Remedial Systems" Dan Raviv Associates (Raviv) recommended modifying the
recovery and treatment system because the system was operating below design capacity and below the
rate needed to create hydraulic control. The current pump and treat system consists of an approximately
200 foot long trench 14 to 16 feet deep that was installed in late 2001, but has not operated except for
testing.
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The RSE team observed a system that is not currently operating. Recommendations to improve the
effectiveness of the system once it is operating include the following:
• addition of short-term extraction events from select monitoring wells using a vacuum
truck
• consideration of indoor air sampling
• evaluation of capture effectiveness
Recommendations to reduce costs include the following:
• a suggestion to reduce the frequency of proposed ground water sampling in the first two
years from quarterly to annual at 10 wells (keeping quarterly sampling at 10 other wells)
• give priority be given to negotiating criteria with the POTW that preclude a need for on-
site treatment of TEA
Recommendations for technical improvement include repairing and labeling vaults and well covers, and
repairing the treatment shed roof. All of these recommendations can be easily implemented, and no
prioritization of the recommendations is needed. After several years of operation, the RSE team suggests
that a switch to air sparging or biosparging be considered in lieu of ground water extraction.
A table summarizing the recommendations, including estimated costs and/or savings associated with
those recommendations, is presented in Section 7.0 of this report.
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PREFACE
This report was prepared as part of a pilot project conducted by the United States Environmental
Protection Agency (U.S. EPA) Office of Underground Storage Tanks (OUST) and Office of Superfund
Remediation and Technology Innovation(OSRTI). The objective of this project is to conduct
Remediation System Evaluations (RSEs) of pump and treat systems managed by State UST programs.
The following organizations are implementing this project.
Organization
Key Contact
Contact Information
U.S. EPA Office of Underground
Storage Tanks (OUST)
Joe Vescio
Joseph P. Vescio
EPA Headquarters 5401G
Ariel Rios Building
1200 Pennsylvania Ave, N.W.
Washington, DC 20460
phone: 703-603-0003
fax: 703-603-0175
vescio j oseph@epa.gov
U.S. EPA Office of Superfund
Remediation and Technology
Innovation
(U.S. EPA OSRTI)
Kathy Yager
11 Technology Drive (ECA/OEME)
North Chelmsford, MA 01863
phone: 617-918-8362
fax: 617-918-8427
yager.kathleen@epa.gov
U.S. EPA Office of Superfund
Remediation and Technology
Innovation
(U.S. EPA OSRTI)
Ellen Rubin
5102G
U.S. EPA Headquarters
Ariel Rios Building
1200 Pennsylvania Avenue, N. W.
Washington, DC 20460
phone: 703-603-0141
rubin.ellen@epa.gov
Dynamac Corporation
(Contractor to U.S. EPA)
Daniel F. Pope
Dynamac Corporation
3601 Oakridge Boulevard
Ada, OK 74820
phone: 580-436-5740
fax: 580-436-6496
dpope@dynamac. com
GeoTrans, Inc.
(Contractor to Dynamac)
Doug Sutton
GeoTrans, Inc.
2 Paragon Way
Freehold, NJ 07728
phone: 732-409-0344
fax: 732-409-3020
dsutton@geotransinc.com
in
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TABLE OF CONTENTS
EXECUTIVE SUMMARY i
PREFACE iii
TABLE OF CONTENTS iv
1.0 INTRODUCTION 1
.1 PURPOSE 1
.2 TEAM COMPOSITION 2
.3 DOCUMENTS REVIEWED 2
.4 PERSONS CONTACTED 3
.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS 3
1.5.1 LOCATION 3
1.5.2 POTENTIAL SOURCES 3
1.5.3 HYDROGEOLOGIC SETTING 3
1.5.4 RECEPTORS 4
1.5.5 DESCRIPTION OF GROUND WATERPLUME 4
2.0 SYSTEM DESCRIPTION 5
2.1 SYSTEM OVERVIEW 5
2.2 MONITORING PROGRAM 6
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE CRITERIA 7
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 7
3.2 TREATMENT PLANT OPERATION STANDARDS 7
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 PLUME CAPTURE 8
4.2.2 AQUIFER RESTORATION 8
4.3 COMPONENT PERFORMANCE 10
4.3.1 EXTRACTION SYSTEM TRENCH, PUMPS, AND HEADER 10
4.3.2 SEPARATOR AND FILTER 11
4.3.3 AIR STRIPPER 11
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL COSTS 12
4.4.1 UTILITIES 12
4.4.2 NON-UTILITY CONSUMABLES 12
4.4.3 LABOR 12
4.4.4 CHEMICAL ANALYSIS 12
4.5 REGULATORY COMPLIANCE 13
4.6 SAFETY RECORD 13
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT . 14
5.1 GROUND WATER 14
5.2 SURFACE WATER 14
5.3 AIR 14
5.4 SOILS 14
5.5 WETLANDS AND SEDIMENTS 14
iv
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6.0 RECOMMENDATIONS 15
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 15
6.1.1 VACUUM ENHANCED EXTRACTION EVENTS AT MW-8 AND OTHER HOT SPOT WELLS 15
6.1.2 INDOOR AIR ANALYSIS OR CONFIRMATION OF CONTROLS 15
6.1.3 REVIEW CAPTURE EFFECTIVENESS AFTER CONSISTENT OPERATION is ESTABLISHED 15
6.2 RECOMMENDATIONS TO REDUCE COSTS 16
6.2.1 REDUCE WELL SAMPLING 16
6.2.2 AVOID TEA TREATMENT 16
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT 17
6.3.1 HOUSEKEEPING 17
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT 17
6.5 SUGGESTED APPROACH TO IMPLEMENTATION 17
7.0 SUMMARY 18
List of Tables
Table 7-1. Cost summary table
List of Figures
Figure 1-1. Site location map
Figure 1-2. Shorco South Site results of analyses of ground water samples February 2002 sampling program
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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 and OUST are performing a pilot study of conducting RSEs at UST sites. During
fiscal year 2003, RSEs at 3 State-managed UST sites were conducted in an effort to evaluate the
effectiveness of this optimization tool for this class of sites. GeoTrans, Inc., a Dynamac contractor, is
conducting these evaluations, and representatives from EPA OUST 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
A 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 (the responsible party, if one exists, and the
regulators) 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. Note that the recommendations are based on an independent evaluation by the RSE
team, and represent the opinions of the RSE team. These recommendations do not constitute
requirements for future action, but rather are provided for the consideration of all site stakeholders. This
RSE report pertains to conditions that existed at the time of the RSE site visit, and any site activities that
have occurred subsequent to the RSE site visit are not reflected in this RSE report (unless otherwise
noted).
The Shorco South site was selected by EPA OUST, in coordination with State agencies. 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.
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1.2
TEAM COMPOSITION
The team conducting the RSE consisted of the following individuals:
Peter Rich, Civil and Environmental Engineer, GeoTrans, Inc.
Doug Sutton, Water Resources Engineer, GeoTrans, Inc.
Rob Greenwald, Hydrogeologist, GeoTrans, Inc.
The RSE team was also accompanied by the following observers:
Joe Vescio, EPA OUST
Judy Barrows, EPA OUST
Rebecca Jamison (EPA Region II)
Jeanette Daduse (EPA Region II)
EPA-OUST is jointly conducting this RSE Pilot Study for UST sites with EPA-OSRTI.
1.3
DOCUMENTS REVIEWED
Author
H2M Associates
EWMA
Dan Raviv Associates
Dan Raviv Associates
Dan Raviv Associates
Dan Raviv Associates
Sadat Associates
Sadat Associates
Sadat Associates
Sadat Associates
Burde Inc. / Sadat
Associates
Sadat Associates
Date
December 2002
December 2001
October 6, 1999
April 30, 1998
January 20, 1998
June 10, 1997
October 1994
July 7, 1994
May 1994
September 1992
June 26, 1991
July 1990
Title
Recommendations Report
Remedial Action Progress report (Shorco North)
Underground Storage Tank Closure Site
Investigation report (Shorco South)
Groundwater Remedial Action Workplan
Proposed Remedial Action Workplan Schedule and
Groundwater Monitoring Proposal
Evaluation of Existing Remedial Systems
Second and Third Quarterly Progress Report for
1994
Response to the NJDEP Comments on the Soil
Remedial Action Report
Soil Remedial Action Report
Phase II Remedial Investigation/Feasibility Study
Groundwater Treatment System O&M Manual
Remedial Investigation/Feasibility Study
All reports are for both Shorco North and South sites unless noted.
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1.4 PERSONS CONTACTED
Tom Ferrara, the site manager from NJDEP, provided site related information and led the RSE team and
observers on a site tour on July 29, 2003. The completion of this report has been delayed due to a
contractual problem that arose in August 2003 and was resolved in May 2004. Due to the delay,
additional information about the site was obtained from Tom Ferraro and Tom O'Neill of NJDEP during
a conference call on June 9, 2004.
1.5 SITE LOCATION, HISTORY, AND CHARACTERISTICS
1.5.1 LOCATION
The Shorco South site is located on the southbound side of Route 17 in the Township of Mahwah, New
Jersey. The site location is shown on Figure 1-1. The Shorco North site is located northeast of the
Shorco South site across Route 17. The Shorco South site remediation is currently being run by NJDEP
under the publicly funded cleanup program while the Shorco North remediation is still being operated by
the responsible party. This RSE focuses on the Shorco South site, and the Shorco North site is discussed
only in relation to its impact on Shorco South.
1.5.2 POTENTIAL SOURCES
Petroleum impacts at the Shorco South site were discovered in 1986. Observations from several
inspections that year included leaks from the eight above ground storage tanks (ASTs), soil staining,
sheens and vapors in the site restaurant basement, product in excavations for septic system installation,
and perforations in USTs. The eight ASTs were removed from the southern corner of the site in April
1987, and 344 cubic yards of contaminated soils were removed at that time. During June and July 1987
the USTs and piping at the pump islands in the middle of the site were replaced. Holes were noted in the
removed USTs and product was seen on the ground water. The RI/FS dated 1990 noted that two
previous USTs were located east of the pump islands. These USTs were apparently removed prior to
1990. A 2000 gallon UST was removed from adjacent to the tire room on the northern portion of the site
in 1992. A small amount (<50 cubic yards) of contaminated soil was removed from two areas on the
western portion of the site in 1993.
Impacted soil within the water table fluctuation zone and possibly shallower soil likely provides a
continuing source to on-site dissolved ground water contamination. In addition, spills, overfills, or
leakage from the existing UST system could potentially be providing continuing source of soil and
ground water contamination. Shorco North, which is hydraulically upgradient of Shorco South, appears
to be a source of ground water impacts to Shorco South.
1.5.3 HYDROGEOLOGIC SETTING
Depth to ground water at the site typically ranges from about 5 to 10 feet below ground surface. The
shallow ground water occurs in a surficial sand and gravel layer that extends to 12 to 23 feet deep at the
site. A silty clay layer has been encountered in all deep site boreholes and is 35 and 50 feet thick at the
two boreholes advanced through the unit. This silty clay layer overlies the deeper aquifer used for local
ground water supply. The most recent analysis of deep ground water (in 1998) indicated no detections of
impacts in downgradient wells located in the deeper aquifer (JOSMW-19D and JOSMW-21D).
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Ground water flows in a south to southwest direction across the site. The site is downgradient of the
Shorco North site, which also has ground water impacted with petroleum constituents. From the Shorco
South site ground water flows towards the Ramapo River (see Figure 1-2). A reported sanitary sewer
installed south of the site in South Houvenkopf Road may provide a preferential shallow ground water
flow path from the southern corner of the site towards well JOSMW-17S (see Figure 1-2).
The hydraulic gradient as measured in 1998 was about 0.01 ft/ft under non-pumping conditions.
Hydraulic conductivity based on pumping test results ranges from 28 to 85 ft/day.
1.5.4 RECEPTORS
The primary potential receptor is the surface water of the Ramapo River about 400 feet southwest of the
site. MTBE and TEA impacts are present in JOSMW-19S about 100 feet from the river.
In addition, Mahwah water supply wells are located about 2,300 feet southwest of the site. A Leggette,
Brashears and Graham (LEG) report dated 1987 evaluated the threat of the Shorco sites to the well field.
The report concluded that the well field is in more direct hydraulic connection with the deeper aquifer
than with the shallow aquifer. The lack of impacts in the deep wells at Shorco South and the fact that no
contaminants had reached the well field indicated that the threat is minimal. The 150 foot deep Shorco
South production well was abandoned to prevent any cross contamination of the deeper aquifer.
1.5.5 DESCRIPTION OF GROUND WATER PLUME
Contaminants of primary concern include benzene, toluene, ethylbenzene and xylene (BTEX), MTBE,
and TEA. Based on the H2M Report (2002) lead concentrations above ground water criteria were also
detected in some wells in 1997 when traditional sampling methods were employed, but not in 1998 when
low-flow techniques were utilized. This suggests the lead impacts in 1997 were likely due to suspended
solids associated with the purging. Benzene, MTBE and TEA are the best indicators of remediation
progress due to the low cleanup criteria for benzene and the high solubility and lack of adsorption of
MTBE and TEA. Figure 1-2 depicts the site monitoring wells and the extent of benzene (1 ug/L
contour), MTBE (70 ug/L contour), and TEA (100 ug/L) dissolved phase plumes in February 2002.
Based on the February 2002 sampling results, ground water impacts are observed at wells located at the
upgradient portion of the Shorco South site (e.g., wells JOSMW-5, RWS-1, MW-9 and RWS-2). These
impacts are likely caused by the Shorco North site, and the impacts are relatively low compared to the
higher concentrations elsewhere on the Shorco South property that likely result from Shorco South
sources. In the central portion of the Shorco South site, liquid petroleum hydrocarbon (LPH) has been
observed in MW-8, and high dissolved concentrations are observed in MW-6. Dissolved levels of
benzene over 100 ug/L and MTBE over 1,000 ug/L extend downgradient to the southern corner of the
site where well points were installed in 1996. Detectable concentrations of MTBE and TEA extend at
least 300 feet off-site to the south and southwest. JOSMW-19S had an MTBE concentration of 300 ug/L
about 100 feet from the Ramapo River.
A review of historical data indicates that MTBE concentrations in ground water in the vicinity of the
Shorco South USTs and pump islands spiked in the 1994, 1995, and 1997 sampling events in comparison
to earlier results (see Section 4.2.2). Maximum dissolved benzene and MTBE concentrations have
subsequently decreased significantly in comparison to the November 1995 and January 1997 sampling
events. The extent of the dissolved benzene and MTBE plumes are similar to the 1995 configurations
except for a substantial MTBE decrease in JOSMW-17S (from 1,500 ug/L in November 1995 to 8 ug/L
in February 2002). The TEA plume is offset slightly south of the benzene and MTBE plumes.
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2.0 SYSTEM DESCRIPTION
2.1 SYSTEM OVERVIEW
A ground water pump and treat system was completed during 1991 which included six recovery wells, an
oil/water separator, bag filters, a packed tower air stripper, and GAC, with discharge to surface water.
Nine well points were added to the system in 1996 to improve containment at the downgradient south
corner of the site. The well points were not effective due to iron fouling problems. In the June 10, 1997
"Evaluation of Existing Remedial Systems" Dan Raviv Associates (Raviv) recommended modifying the
recovery and treatment system because the system was operating below design capacity and below the
rate needed to create hydraulic control. The system recovery wells capable of yields over 1 gpm were
located mainly upgradient of the greatest site impacts. The treatment system also had significant iron
fouling problems. Based on the Second and Third Quarterly Progress Report for 1994 the system was
typically treating about 3-5 gallons per minute. Raviv stated that the existing treatment system did not
have adequate capacity to handle the anticipated recovery flow rate of a modified recovery system.
The current pump and treat extraction system consists of an approximately 200 foot long trench 14 to 16
feet deep that was installed in late 2001. The trench has a northwest to southeast alignment on the west
side of the Shorco South site from near JOSMW-1 to near PWS-9 (see Figure 1-2). Raviv predicts a
pumping rate of 5 to 10 gpm to maintain a drawdown of six feet within the trench and intercept the width
of the ground water plume. A submersible pump operated with level controls will pump water from the
trench sump to an underground oil/water separator (reported to be a Highland Tank Model HTC-J
350™). From the separator the water will be pumped to a bag filter (to be installed) and then a "Breeze"
Aeromix™ diffusion air stripper with a 3 HP regenerative blower. Emissions from the air stripper will be
discharged through a stack directly to the atmosphere and treated water will be discharged to the North
Bergen Municipal Utility Authority (MUA) publicly owned treatment works (POTW). The NJDEP and
Handex are currently working to obtain a permit. The treatment system is proposed to have treatment
capacity to 25 gpm. The system will also have failsafes, alarms, and an autodialer to allow unattended
operation. The system has undergone some initial test operation and appears capable of sustaining at
least 5 gpm yield, but continuous operation has been delayed since a discharge agreement has not been
finalized.
This current trench-based system will allow the downgradient plume to go untreated. In the April 30,
1998 "Ground Water Remedial Action Workplan" Dan Raviv Associates proposes "natural remediation"
for the parcels downgradient of the site. Raviv states the "worst-case" Classification Exception Area
(CEA) calculations for MTBE indicate that the plume will not reach the Ramapo River. The Ramapo
River is the nearest sensitive receptor to the site. Based on 2002 sampling data, it is possible that low
concentrations of MTBE and TEA may be discharging to the river. Even if some discharge is occurring
it is likely to have negligible or minimal impact due to dilution.
Ground water upgradient of the trench is not being actively treated, and even if no new contamination is
being introduced into the subsurface, it will take a substantial time period (many years) for existing
impacts to be flushed out.
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2.2 MONITORING PROGRAM
The monitoring program has historically consisted of periodic sampling and analysis at select wells for
BTEX and MTBE. Approximately nine well sampling events have been conducted since 1992.
Raviv proposed in the 4/30/98 Work Plan that 20 Shorco South wells be sampled quarterly with analysis
for BTEX, MTBE and TEA, with 12 additional wells sampled annually. NJDEP is considering that
general approach, with the potential for the quarterly ground water sampling to be reduced to semiannual
after two years. In addition a post-remediation (after system shut-down) sampling plan is proposed that
includes 11 wells to be sampled quarterly for two years. Short-term monthly sampling is also proposed
at system startup.
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3.1
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE
CRITERIA
CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
The NJDEP ground water cleanup criteria that serve as remediation goals for the site are as follows:
Contaminant
Benzene
MTBE
TEA
Toluene
Ethylbenzene
Xylenes
Lead
NJDEP Standard
lug/L
70ug/L
100 ug/L
1,000 ug/L
700 ug/L
1,000 ug/L
10 ug/L
Dissolved benzene, MTBE, and TEA levels are still present in many wells above these criteria and are
good "indicator parameters" for continuing impacts at the site. Toluene, ethylbenzene, xylene, and lead
only sporadically exceed the criteria, and occur at wells within the plumes associated with the three
indicator parameters (benzene, MTBE, and TEA). When the three indicator parameters are successfully
remediated, it is likely that the other parameters will also be remediated.
Natural remediation is planned for the area downgradient of the trench capture zone, where MTBE and
TEA are present at levels above NJDEP standards. A Classification Exception Area (CEA) was
proposed for this downgradient area by Raviv and NJDEP has apparently agreed to this approach. Raviv
also proposes a CEA for the area within the proposed capture zone after a "significant reduction" in
ground water contamination has occurred, but specific concentration levels and a specific time period
have not been established.
3.2
TREATMENT PLANT OPERATION STANDARDS
Initial operational tests of the system accomplished after the RSE visit indicate that the trench will likely
be able to recover about 10 gpm, based on qualitative drawdown observations in the trench sump.
Continuous operation of the system has been delayed due to discharge permitting difficulties, and
therefore standards for the system effluent have not been finalized. System effluent concentrations
during the testing were reported to be 18 ug/L benzene, 525 ug/L MTBE and 16,500 ug/L TEA. NJDEP
reported that the TEA level may be above POTW pretreatment standards.
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4.0 FINDINGS AND OBSERVATIONS FROM THE RSE SITE VISIT
4.1 FINDINGS
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, NJDEP, 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 over time.
4.2 SUBSURFACE PERFORMANCE AND RESPONSE
4.2.1 PLUME CAPTURE
The original ground water extraction system consisted of six recovery wells. Pumping from these wells
did not provide adequate plume capture. Nine well points were placed in the downgradient corner of the
site to augment plume capture, but they were not effective due to solids production and low yields. The
original recovery system has been replaced with a 200 foot long, 14 to 16 foot deep trench located on the
southwest side of the site. Based on calculations by Raviv that utilize previous hydraulic conductivity
estimates, this trench should be effective in maintaining a capture zone across the target area if pumping
of 5 to 10 gallons per minute is achieved (as discussed in Section 3.2, approximately 10 gpm was
achieved in testing done subsequent to the RSE visit). A similar calculation is provided below using
representative parameters that are discussed in Section 1.0 of this report:
Q = CxWxBxKxi = C x 200 ft x 15 fix 50 ft/day x 0.01 = 7.8 gpm
where
Q is the pumping rate (gpm) B is the saturated thickness
C is a conversion factor (0.00518 gal/ft3 min/day) K is the hydraulic conductivity (ft/day)
W is the width of the trench(ft) /' is the hydraulic gradient (ft/foot)
This simple calculation, which is sensitive to the parameters used and a number of simplifying
assumptions, indicates that a pumping rate of 7.8 gpm is required to intercept ground water flowing to the
trench. When evaluating capture, it is often preferable to have a factor of safety of 1.5 to 2.0. Therefore,
although effective capture is possible at 7.8 gpm, based on the parameters used, it would be preferable to
achieve an extraction rate of 10 to 15 gpm.
4.2.2 AQUIFER RESTORATION
Concentration data (benzene, MTBE, and TEA) at selected monitoring wells are presented on the
following page. These wells were selected to illustrate concentration trends in three portions of the site:
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• on-site wells located upgradient of the on-site sources ("upgradient")
• on-site wells located near current and historic USTs and pump islands ("mid-plume")
• downgradient of the "mid-plume" wells, both on-site and off-site ("downgradient")
The locations of the selected wells are presented in Figure 1-2, and dissolved concentrations for February
2002 are also presented in Figure 1-2.
Monitoring
Well
Date
NJDEP Standard
MTBE (ug/L)
70
Benzene (ug/L)
1
TEA (ug/L)
100
Upgradient Wells
RWS-1
JOSMW-5
Apr. 1992
Aug. 1993
Sep. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
Apr. 1992
Aug. 1993
Sep. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
260
2,400
15,000
12,000
19,000
550
1,300
28
150
ND
ND
ND
30
1,200
293
91
520
940
1,100
67
45
142
97
ND
590
400
340
400
190
15
22
5
ND
ND
1,400J
30
ND
ND
ND
7
Mid-Plume Wells
MW-6
MW-7
Apr. 1992
Jul. 1993
Sep. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
Aug. 2003
Aug. 1993
Sep. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
Aug. 2003
1,100
5,100
86,000
140,000
50,000
15,500
16,300
1,600
97
95
ND
19,000
860
8,300
13,500
570
3,500
510
980
ND
3,200
2,200
1,160
1,280
900
10
320
11
1,900
980
661
644
36
60
ND
ND
ND
36,000
ND
ND
24
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Monitoring Well
Date
NJDEP Standard
MTBE (ug/L)
70
Benzene (ug/L)
1
TEA (ug/L)
100
Downgradient Wells
PWS-4
JOSMW-17S
JOSMW-19S
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
Aug. 2003
Apr. 1992
Jul. 1993
Aug. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
Apr. 1992
Jul. 1993
Aug. 1994
Nov. 1995
Jan. 1997
Feb. 1998
May 1998
Feb. 2002
2,300
1,500
3,960
4,550
2,200
580
270
143
39
1,500
800
109
270
8
ND
ND
39
250
174
77
97
300
380
8
110
89
280
5
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
15,000
ND
ND
ND
260
110
152
73
9.3
Sampling results since 1992
On-site wells located upgradient of on-site sources ("upgradient" wells) are impacted, but at lower
concentrations than the "mid-plume" wells. Impacts at these "upgradient wells" are most likely due to
Shorco North, and concentrations at these wells are decreasing over time. At the "mid-plume" wells
(impacted primarily by sources at Shorco South) the concentrations also appear to be decreasing over
time, though in some cases concentrations still remain several orders of magnitude above cleanup
criteria. Trends at the "downgradient" wells are not as clear.
MW-8 was the only remaining well with free product in 2002.
free product was found in the well.
In the August 2003 sampling round no
4.3
COMPONENT PERFORMANCE
The new treatment system has only operated for short term tests, so performance information is based on
design estimates and test data provided by NJDEP. System effluent concentrations during the testing
were reported to be 18 ug/L benzene, 525 ug/L MTBE and 16,500 ug/L TEA. Although these effluent
levels are in excess of ground water criteria, these concentrations may meet POTW pretreatment
standards (which have not yet been finalized). If not, more effective treatment will be required.
4.3.1
EXTRACTION SYSTEM TRENCH, PUMPS, AND HEADER
Initial tests indicate that the extraction trench will yield about 10 gpm. No problems with the
submersible extraction pump or level controls were noted.
10
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4.3.2 SEPARATOR AND FILTER
Extracted ground water is transferred to an underground oil/water separator. The separator model is
reported to be a Highland Tank HTC-350™. This is a 350 gallon volume unit rated for up to 35 gallons
per minute. Given that free product is not accumulating in monitoring wells at the site, little or no
product should be expected to be collected in the separator.
The current plan is to pump the water from the separator to a bag filter system to remove suspended
solids prior to the air stripper. The bag filter system had not been installed at the time of the RSE site
visit. An appropriate bag filter opening size will be determined to minimize solid loading to the air
stripper while not requiring excessive operator attention to change-out bags.
4.3.3 AIR STRIPPER
The air stripper is a "Breeze" Aeromix™ unit with a three horsepower regenerative blower. The H2M
report states that at the 25 gpm design capacity, about 90% removal of BTEX compounds and 70%
removal of MTBE is predicted with this stripper. Removal efficiency increases with the lower flow rates
anticipated at Shorco South. For example, at 10 gpm, the removal rate of MTBE may be 90%.
Information was not available for removal of TEA.
The Aeromix™ air stripper is relatively inefficient for volatiles removal due to its use of diffusers in a
water column. However, this type of air stripper is less prone to fouling than more efficient packed tower
and tray stripper units. If the Aeromix™ stripper effluent meets POTW pretreatment standards, then it is
very appropriate for use at this site.
The system test effluent analysis reported by NJDEP indicated effluent concentrations of 18 ug/L
benzene, 525 ug/L MTBE and 16,500 ug/L TEA. Based on the predicted system efficiencies (90% for
BTEX and 70% for MTBE), system influent levels are estimated at >180 ug/L benzene and >1,750 ug/L
MTBE. These estimated influent levels are consistent with the high end of the monitoring well analytical
results from the August 2003 sampling event for wells in the vicinity of the trench. Influent
concentrations (and therefore mass removal) are expected to decrease once continuous pumping begins.
At the estimated influent concentrations and an average flow rate of 10 gpm, 0.02 pounds/day of benzene
and 0.21 pounds/day of MTBE will be removed from the site ground water and discharged to the
atmosphere or the POTW.
10 gal. 180 ug benzene 3.785 L 1440 min. 2.2 Ibs _ 0.02 Ibs benzene
• X X X X
min. L gal. day 109 ug day
10 gal. 1,750 ug MTBE 3.785 L 1440 min. 2.2Ibs 0.21 Ibs MTBE
•X X X X —
min. L gal. day 10 ug day
11
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4.4
COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
ANNUAL COSTS
The treatment system is not currently being operated, so the cost breakdown provided below is based on
estimates for the proposed scope and information provided by NJDEP. NJDEP plans to contract with
Handex to run the new treatment system. The total cost for the system O&M is planned at about
$100,000 per year, including sampling costs and POTW fees. Electrical costs are not included since the
service station pays the electrical bills.
Item Description
System operation and maintenance
PM and Reporting
Sampling and well gauging
Electricity
POTW (reported to decrease to $21K/yr after 1st year)
Laboratory analysis
Total Estimated Cost
Estimated Cost
per Year
$30,000
$12,000
$23,000
Paid by others
$26,000
$12,000
$103,000
4.4.1
UTILITIES
The main site utility paid by NJDEP is for POTW discharge. NJDEP reports that fees during the first
year will be $26,000 and for additional years fees will be $21,000. A per gallon cost rate was not
provided but it appears to be less than $0.01 per gallon, which is reasonable compared to other rates we
have seen in New Jersey.
4.4.2
NON-UTILITY CONSUMABLES AND DISPOSAL COSTS
Disposal costs will consist mainly of the disposal of filter bags (assuming GAC is not used), and those
costs will be minimal (not quantified).
4.4.3
LABOR
Operator labor will consist of periodic site visits to clean the air stripper and other system components,
and to replace bag filters. We assume 50 hours per month at $50 per hour for the cost estimate. Project
management and reporting costs are expected to be about $1,000 per month. Well sampling costs are
estimated at $250 per sample with 92 total samples per year.
4.4.4
CHEMICAL ANALYSIS
Chemical analysis costs are assumed to be $100 per well sample, plus $700 per quarter for POTW
required analysis.
12
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4.5 REGULATORY COMPLIANCE
The Second and Third Quarterly Progress report for 1994 noted NPDES permit exceedances for TOC,
TPHC and toluene. Iron fouling of the packed tower air stripper media was the reported cause of the
elevated effluent values. Because the POTW (proposed for future discharge) has less stringent standards,
these issues should not be a problem with the new system, although the POTW criteria have not been
finalized.
4.6 SAFETY RECORD
The site team did not indicate any reportable incidents.
13
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
Based on the current site conceptual model, site contamination in ground water will likely not impact the
Mahwah Well Field. There are no other potable supply wells in the vicinity of the site. The on-site
supply well was apparently abandoned in the mid 1990s.
5.2 SURFACE WATER
Calculations in the Raviv Groundwater Remedial Action Workplan indicate that the ground water
impacts will not reach the Ramapo River. Even if low levels of MTBE or TEA were to reach the river,
dilution and volatilization would likely render these constituents undetectable.
5.3 AIR
The on-site service station related buildings are the only structures over the site ground water plume.
Indoor air impacts were considered qualitatively in site inspections in the late 1980s. Our review did not
find any analysis of indoor air, discussion of ongoing building venting, or recent complaints regarding
indoor air quality. Given that service station tank and piping conditions have improved, and ground
water contaminant concentrations are declining overtime, it is likely that any indoor air impacts (if any)
are reduced from previous levels. However, it may be prudent for NJDEP to analyze indoor air quality
and/or inspect any venting systems, to determine if any additional remediation efforts are warranted.
5.4 SOILS
Varying amounts of contaminated soils have been removed in several efforts at the site. Contaminated
soil may be a continuing source of ground water contamination at the site but the site is covered with
paving and buildings so that any exposure to impacted soils is limited except during excavating.
5.5 WETLANDS AND SEDIMENTS
MTBE and TEA are the constituents most likely to migrate to surface water. We did not specifically
evaluate these media, but the concentrations reaching surface water in wetlands would likely be quite low
and subject to subsequent volatization. The constituents of concern at the site do not typically sorb to
sediments.
14
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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 VACUUM ENHANCED EXTRACTION EVENTS AT MW-8 AND OTHER HOT SPOT WELLS
Aquifer restoration with the current system may take a considerable amount of time, considering that the
trench is located about 100 feet from wells that have high levels of dissolved contamination (e.g. MW-8)
and vadose zone soil impacts may continue to serve as a source of dissolved ground water impacts. One
approach to speed restoration might be sparging, but introducing air into the subsurface by sparging
while the ground water recovery system is operating may cause significant iron fouling. A more
conservative approach that may succeed is short-term extraction (about 2-4 hours per well) of liquid and
vapor from hot-spot wells with a vacuum truck. We recommend considering such events quarterly for
one year at 2-4 monitoring wells on the site with the greatest concentrations. This should require about
$2,000 per one day event, or approximately $8,000 for one year. In addition to speeding site restoration,
this approach may reduce influent concentrations to the treatment system, which might make it easier to
meet effluent standards required by the POTW.
6.1.2 INDOOR AIR ANALYSIS OR CONFIRMATION OF CONTROLS
NJDEP should consider verifying that indoor air ventilation is adequate or analyze indoor air within
occupied structures at the site. Assuming four samples are taken and analyzed, this effort would require
about $5,000 for a one time event.
6.1.3 REVIEW CAPTURE EFFECTIVENESS AFTER CONSISTENT OPERATION is ESTABLISHED
The water budget analysis suggests that the trench extraction rate is comparable to the rate at which
ground water flows through the target capture zone. However, given uncertainties in the parameters used
to conduct the water budget analysis, results are not sufficiently conservative to conclude that capture is
provided. Additional lines of evidence such as the use of potentiometric surface maps and concentration
trends in downgradient wells should also be used.
There may be a sufficient number of wells and piezometers to collect enough information to provide an
informative potentiometric surface. A potentiometric surface map developed with water levels from each
available well/piezometer on the Shorco South site should be used to generate a potentiometric surface
map and interpret ground water flow directions. Such analyses would be helpful on a quarterly basis for
one to two years and annually thereafter.
In general, the concentrations in wells that are downgradient of the trench and trench capture zone should
decrease over time if capture is sufficient. However, substantial contamination remains in place
downgradient of the trench. Concentrations in the more contaminated downgradient wells should
15
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decrease overtime; however, concentrations in some of the less contaminated downgradient wells may
increase over time if the contamination that is already downgradient of the trench migrates over time.
Analysis of capture effectiveness based on trench yield, water level measurements, and concentration
trends in monitoring wells downgradient of the trench should be routinely conducted as part of the O&M
contract. Assuming the necessary field work is already included in the contract, this review could cost
about $5,000 in the first year. In subsequent years, the capture zone analyses would be done as part of
preparing the annual reports, and the cost would be included in the cost of preparing those annual reports.
6.2 RECOMMENDATIONS TO REDUCE COSTS
It is difficult to make recommendations for costs savings because system operations have yet to begin and
the RSE team has not reviewed the contractor's scope and cost breakdown. In addition, the level of total
annual cost reported by NJDEP is relatively low. NJDEP should consider reviewing system operational
data after one year of continuous operation to determine if the system is achieving containment and
treatment goals and if progress is seen towards aquifer restoration. Costs should also be reviewed at that
time to determine if any unexpected operational changes or difficulties have increased cost components.
If any cost items are significantly different than those estimated in Section 4.4, NJDEP may want to
determine the reason for the differences.
6.2.1 REDUCE WELL SAMPLING
The proposed monitoring well sampling program (Raviv, 1998) includes 20 wells sampled quarterly plus
12 additional wells sampled annually for the first two years of system operation, with the quarterly
sampling frequency reduced to semiannual thereafter. NJDEP should consider reducing the number of
wells sampled quarterly to about 10 key wells (for example, those included in the table in Section 4.2.2)
with the remainder sampled annually for the first two years of system operation. Thereafter a semiannual
sampling frequency is reasonable. With over 15 years of ground water monitoring trends available,
collecting a large quantity of quarterly data is unlikely to be productive for decision making. Brief
quarterly reports should be produced to note monitoring data, and system operation including POTW
discharge compliance. Annual reports should be produced describing ground water concentration trends,
recovery and treatment system operational details such as volume pumped, mass removed, and system
effectiveness as indicated by water level measurements, influent and effluent analysis, and uptime
percentage. This would reduce the total number of well samples by 30 for the first two years and by 10
thereafter for an assumed eight additional years of system operation. Based on our estimates this
represents a potential savings of $10,500 for the first two years and $3,500 per year thereafter.
6.2.2 AVOID TEA TREATMENT
Separate TEA treatment costs are not currently included in system cost estimates. However TEA levels
in the system influent may require treatment depending on the final agreement with the POTW. TEA
concentrations at the high levels seen in the system tests should be readily treated by the typical
biological treatment at a POTW, and we recommend that NJDEP pursue further negotiations perhaps to
include paying additional fees to the POTW, rather than using GAC or another technology to attempt to
remove TEA on-site. While GAC systems often remove TEA due to biological growth within the vessel,
filtering prior to the GAC to prevent fouling may require considerable capital and/or operating expense
for additional bag filters and changeouts or iron precipitation. NJDEP may need to evaluate potential
treatment options if further TEA treatment is required and GAC does not provide the desired results.
Other possible alternatives include more efficient air stripping, UV/Oxidation, and fluidized bed
16
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bioreactors (using GAC as the fixed growth media). Any of these options would have associated capital
costs and iron fouling issues to consider.
It should also be noted that TEA concentrations should decline over time due to the remedy (particularly
if remediation is accelerated by the actions recommended in Section 6.1.1), and the need for treatment of
TEA (if any) may only be for the short-term.
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT
6.3.1 HOUSEKEEPING
The remediation system is in generally poor condition (including the investigation and remediation
related construction). NJDEP should consider making the effort to repair and label vaults and well
covers. More importantly, the treatment system shed roof needs to be repaired. These improvements may
already be planned. The RSE estimates that approximately $5,000 could significantly improve site
conditions.
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT
The system will likely provide capture of the plume upgradient and slightly downgradient of the trench.
However, the contaminant mass removed by the trench will likely have a minimal impact on cleaning up
the site. Based on the concentration trends from 1995 to 2002 it is likely that natural remediation
processes are the most significant factor in cleaning up the site. As discussed in Section 6.1.1, if NJDEP
desires to accelerate the site cleanup beyond what will occur with natural processes, short-term extraction
(about 2-4 hours per well) of liquid and vapor from hot-spot wells with a vacuum truck is suggested. An
air sparging or biosparging approach could also be considered in lieu of ground water extraction after it
is determined that hydraulic containment of site ground water is no longer necessary (sparging would
likely cause fouling of an operating extraction system).
6.5 SUGGESTED APPROACH TO IMPLEMENTATION
The recommendations included in Section 6.1 to 6.3 are straightforward and could be implemented in the
first year of system operation. We recommend the consideration of a sparging approach as discussed in
Section 6.4 after several years, as a possible alternative in lieu of continued extraction.
17
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7.0 SUMMARY
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 and the public. These recommendations have the obvious benefit of being
formulated based upon operational data unavailable to the original designers.
The RSE team observed a system that is not currently operating. Recommendations to improve the
effectiveness of the system once it is operating include the addition of short-term extraction events from
select monitoring wells using a vacuum truck, consideration of indoor air sampling, and making sure that
capture effectiveness is evaluated. Recommendations to reduce costs include a suggestion to reduce the
frequency of proposed ground water sampling in the first two years from quarterly to annual at 10 wells
(keeping quarterly sampling at 10 other wells). It is also suggested that priority be given to negotiating
criteria with the POTW that preclude a need for on-site treatment of TEA. Recommendations for
technical improvement include repairing and labeling vaults and well covers, and repairing the treatment
shed roof. All of these recommendations can be easily implemented, and no prioritization of the
recommendations is needed. After several years of operation, the RSE team suggests that a switch to air
sparging or biosparging be considered in lieu of ground water extraction.
Table 7-1 summarizes the costs and cost savings associated with each recommendation in Sections 6.1
through 6.4. Both capital and annual cost estimates are presented. Also presented is the expected change
in life-cycle costs over a 10-year period for each recommendation both with discounting (i.e., net present
value) and without it.
18
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Table 7-1. Cost Summary Table
Recommendation
6.1.1 Vacuum-enhanced
extraction events for one year
6. 1.2 Indoor air analysis
6.1.3 Initial capture evaluation
6.2. 1 Reduce well sampling
6.2.2 Avoid TEA treatment
6.3.1 Housekeeping
6.4. 1 Recommendations for
site closeout
Reason
Effectiveness
Effectiveness
Effectiveness
Reduce Costs
Reduce Costs
Technical
Improvement
Gain
Site/System
Closeout
Additional
Capital
Costs
($)
$8,000
$5,000
$5,000
not quantified
$5,000
not quantified
Estimated
Change in
Annual
Costs
($/yr)
($10,500)
yrl-2
($3,500)
yr3-10
not quantified
not quantified
Estimated
Change
In Life-cycle
Costs
(S)1
$8,000
$5,000
$5,000
($49,000)
not quantified
$5,000
not quantified
Estimated
Change
In Life-cycle
Costs
($)2
$8,000
$5,000
$5,000
($42,000)
not quantified
$5,000
not quantified
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
19
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FIGURES
-------
FIGURE 1. SITE LOCATION MAP
SHORCO NORTH
-
SHORCO SOUTH
SCALE IN FEET
(Note: This figure is taken from Ramsey, NJ-NY U.S.G.S. Quadrangle, 1955.
Quadrangle Location
-------
FIGURE 2. SHORCO SOUTH SITE RESULTS OF ANALYSES OF GROUNDWATER SAMPLES FEBRUARY 2002 SAMPLING PROGRAM.
MW-7
SCREEN INTERVAL: 3'-18' BGS
BENZENE 36 ug/L
RWS-3
SCREEN INTERVAL: 6'-21' BGS
BENZENE ND
MTBE 3.7 ug/L
570 ug/L
24 ug/L
JOSMW-5
SCREEN INTERVAL: 3'-18' BGS
BENZENE 5 ug/L
MW-10
SCREEN INTERVAL: 3'-18' BGS
BENZENE ND
MTBE 220 ug/L
TBA 33 ug/L
MW-13
SCREEN INTERVAL: 3'-18' BGS
BENZENE 2 ug/L
MTBE 86 ug/L
TBA 10 ug/L
LOTS
BLOCK 26
SHORCO
SOUTH
RWS-1
SCREEN INTERVAL: 5.6'-20.6' BGS
BENZENE ND
MTBE 28 ug/L
30 ug/L
RWS-6
SCREEN INTERVAL: 5.5'-20.5' BGS
BENZENE ND
MTBE 15 ug/L
TBA ND
JOSMW-1 8D®
JOSMW-18S®
SHORCO
NORTH
RWS-5
SCREEN INTERVAL: 5'-20' BGS
BENZENE ND
MTBE 27 ug/L
TBA 16 ug/L
9 x
MW-8 /RWS-1
MW-9
SCREEN INTERVAL: 3'-1B' BGS
BENZENE 6 ug/L
36 ug/L
610 ug/L
JOSMW-4
PWS-4
MW-6
SCREEN INTERVAL: 3'-19' BSS
BENZENE 900 ug/L
1,600 ug/L
36,000 ug/L
JOSMW-19S
SCREEN INTERVAL: 13'-23' BGS
BENZENE ND
MTBE 300 ug/L
TBA 9.3 ug/L
RWS-2
SCREEN INTERVAL: 4'-14' BGS
BENZENE ND
MTBE 82 ug/L
TBA 1,700 ug/L
MW-4
SCREEN INTERVAL: 2'-17' BGS
BENZENE ND
MTBE 21 ug/L
53 ug/L
NOTES:
ND: NOT DETECTED
ALL RESULTS FOR COMPOUNDS DETECTED
ABOVE GROUNDWATER QUALITY CRITERIA ARE
SHOWN. (MTBE AND TBA INTERIM GROUND
WATER QUALITY CRITERIA ARE 70 ug/L AND
100 ug/L).
THE FOLLOWING WELLS WERE NOT SAMPLED:
MW-8, MW-11, MW-12, MW-14, PWS-2,
PWS-3, PWS-5, PWS-7, PWS-8, PWS-9,
JOSMW-1, JOSMW-3, JOSMW-4, JOSMW-17M,
JOSMW-18S, JOSMW-18D, JOSMW-19D,
JOSMW-20S, JOSM-021S, JOSMW-21D,
JOSMW-22S, RWS-4, JOSPZ-1, JOSPZ-2,
JOSPZ-3, JOSPZ-4.
MTBE: METHYL TERTIARY BUTYL ETHER
TBA: TERTIARY BUTYL ALCOHOL
INFORMATION SHOWN IS FROM A SCANNED
IMAGE AND IS APPROXIMATE.
PWS-4
SCREEN INTERVAL: UNKNOWN
BENZENE 280 ug/L
MTBE
TBA
2,200 ug/L
15,000 ug/L
/JOSMW-17M
V
PWS-6
SCREEN INTERVAL: UNKNOWN
BENZENE 570 ug/L
MTBE 230 ug/L
TBA 33,000 ug/L
JOSMW-1 7S
SCREEN INTERVAL: 6'- 16' BGS
BENZENE ND
MTBE 8 ug/L
TBA 260 ug/L
150
SCALE IN FEET
300
LEGEND
GROUNDWATER MONITORING WELL
RECOVERY WELL OR WELL POINT
• PROPERTY LINE
RECOVERY TRENCH
APPROXIMATE
' ALIGNMENT
APPROXIMATE
DIRECTION
GROUNDWATER FLOW
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