OPTIMIZATION SUPPORT EVALUATION
GREENWOOD CHEMICAL SITE
NEWTOWN, VIRGINIA
Report of the Optimization Support Evaluation,
Site Visit Conducted at the Greenwood Chemical Site
August 7, 2003
-------
This page is intentionally left blank.
-------
Office of Solid Waste EPA 542-R-04-032
and Emergency Response April 2004
(5102G) www.epa.gov/tio
clu-in.org/optimization
Optimization Support Evaluation
Greenwood Chemical Site
Newtown, Virginia
-------
This page is intentionally left blank.
-------
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 S&K Technologies Prime Contract No. GS06T02BND0723 and under Dynamac
Corporation Prime Contract No. 68-C-02-092, Work Assignment ST-1-08. Mention of trade names or
commercial products does not constitute endorsement or recommendation for use.
-------
EXECUTIVE SUMMARY
An Optimization Support Evaluation (OSE) involves a team of expert hydrogeologists and engineers,
independent of the site, conducting an 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. In the case of interim remedies (such as this site), an OSE provides recommendations
that are applicable to the interim remedy and are considerations for a final remedy. 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. For an interim remedy, 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
• considerations for a final remedy
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 and represent the opinions of the evaluation team. These recommendations do
not constitute requirements for future action, but rather are provided for the consideration of all site
stakeholders. This OSE report pertains to conditions that existed at the time of the OSE site visit, and
any site activities that have occurred subsequent to the OSE site visit are not reflected in this OSE report.
The Greenwood Chemical Site ("site") is an inactive chemical manufacturing facility located in
Newtown, Albemarle County, Virginia on VA Route 690 approximately 0.75 miles west of the town of
Greenwood, Virginia and approximately 20 miles west of Charlottesville. The area of the Site associated
with chemical manufacturing and waste disposal activity comprises approximately 18 acres. A number
of removal and remedial actions have occurred to address buried drums and contaminated lagoons. Two
lagoons remain at the site, and a ground water P&T system has been implemented as an interim remedy
to extract and treat contaminated ground water and to manage the water levels in the remaining lagoons.
The site is in the Remedial Investigation/Feasibility Study stage, and a number of items, including plume
delineation, remain prior to implementing a final remedy at the site.
In general, the OSE team found a smoothly operating, well-organized treatment plant. 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. These recommendations
have the obvious benefit of being formulated based upon operational data unavailable to the original
designers.
The recommendations to improve effectiveness in protecting human health and the environment include
the following:
• The residential wells and surface water that are near and/or downgradient of the site should be
sampled. Sampling of the residential wells since the Remedial Investigation, if any, is not well
documented. This sampling should help determine if continued migration has allowed
contamination to reach these receptors.
-------
• The plume needs further delineation, particularly at the downgradient edge of the plume. Up to
six locations for new monitoring wells have been recommended to provide this delineation.
• Once delineation is complete a target capture zone should be developed and capture zone
analysis should be conducted. This analysis will help determine the effectiveness of the current
remedy and the potential need for additional extraction points.
• A 1,000-pound vapor GAC unit has been used to treat the vapors that gather in the head space of
the process tanks. This unit has not been changed or sampled since the plant began operation. If
it was deemed important to include this unit in the original design, it is likely important to sample
and determine if breakthrough has occurred. A recommendation is made to sample the influent
and effluent with a PID.
Implementing these recommendations might cost $200,000 to $250,000 in capital costs and $4,000 to
$8,000 in annual costs. However, these costs may be offset by implementing cost reduction
recommendations. The cost reduction recommendations are as follows:
• The treatment plant should be able to run effectively with one full-time operator and minimal
support from a part-time technician. This would be consistent with other similar Fund-lead sites.
Implementing this reduction should reduce costs by approximately $50,000 per year with no
capital costs.
• The lagoon sediments should be addressed so that solids loading to the treatment plant can be
reduced. Although this will not directly reduce costs, it is the first step in allowing the system to
potentially operate without metals precipitation. If metals precipitation can be eliminated, O&M
costs might decrease by another $75,000 to $100,000 per year.
• The UV/Oxidation system may be another reason why metals precipitation is required, but the
UV/Oxidation system provides little benefit in addressing site contaminants. The GAC units
currently provide the bulk of the contaminant removal. The site team should strongly consider
bypassing the UV/Oxidation unit, particularly if it will allow metals precipitation to be
discontinued. In addition, bypassing the UV/Oxidation system may save an additional $20,000
per year.
• The ground water monitoring program includes redundant sampling. Recommendations are
provided that could reduce the monitoring costs by approximately 50%, which might save
approximately $20,000 per year.
• The project management, technical support, and reporting costs and scopes of work should be
reviewed by the site team to determine if any items can be cut to reduce costs without sacrificing
effectiveness. Cost savings for this recommendation are not quantified due to the uncertainty in
the current costs and scopes.
The recommendations for technical improvement are primarily focused on improving data management,
data analysis, and reporting. The considerations for a final remedy include strategies for continuing to
use P&T for plume capture and to use monitoring to demonstrate that capture is adequate. Suggestions
regarding aggressive remediation are made in case the site stakeholders are considering this approach for
the final remedy. Also provided is a cost-effective alternative to the currently proposed RCRA cap
(potentially saving as much as $1.5 million).
11
-------
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
-------
PREFACE
This report was prepared at the request of EPA Region 3 as part of a project to optimize the Region's
pump and treat (P&T) systems that are jointly funded by EPA and the associated State agency. The
effort was made possible with the help of the Office of Superfund Remediation and Technology
Innovation. The project contacts are as follows:
Organization
Key Contact
Contact Information
USEPA Office of Emergency and
Remedial Response
(OSRTI)
Kathy Yager
11 Technology Drive (ECA/OEME)
North Chelmsford, MA 01863
phone: 617-918-8362
fax: 617-918-8427
yager.kathleen@epa.gov
USEPA Region 3
Kathy Davies
USEPA REGION 3
1650 Arch Street
Philadelphia, PA 19103-2029
215-814-3315
davies.kathy@epa.gov
USEPA Region 3
Norm Kulujian
USEPA REGION 3
1650 Arch Street
Philadelphia, PA 19103-2029
215-814-3130
kulujian.norm@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
-------
TABLE OF CONTENTS
EXECUTIVE SUMMARY i
PREFACE iv
TABLE OF CONTENTS v
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 5
1.5.3 HYDROGEOLOGIC SETTING 6
1.5.4 RECEPTORS 8
1.5.5 DESCRIPTION OF GROUND WATERPLUME 8
2.0 SYSTEM DESCRIPTION 10
2.1 SYSTEM OVERVIEW 10
2.2 EXTRACTION SYSTEM 10
2.3 TREATMENT SYSTEM 11
2.4 MONITORING PROGRAM 11
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE CRITERIA 13
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 13
3.2 TREATMENT PLANT OPERATION STANDARDS 14
4.0 FINDINGS AND OBSERVATIONS FROM THE OSE SITE VISIT 15
4.1 FINDINGS 15
4.2 SUBSURFACE PERFORMANCE AND RESPONSE 15
4.2.1 WATER LEVELS 15
4.2.2 CAPTURE ZONES 15
4.2.3 CONTAMINANT LEVELS 17
4.3 COMPONENT PERFORMANCE 17
4.3.1 EXTRACTION SYSTEM WELLS, PUMPS, AND HEADER 17
4.3.2 EQUALIZATION/INFLUENT TANK 17
4.3.3 UV/OXIDATION SYSTEM 18
4.3.4 GAC 18
4.3.5 EFFLUENT TANK AND DISCHARGE 19
4.3.6 SOLID WASTE HANDLING SYSTEM 19
4.3.7 SYSTEM CONTROLS 19
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF MONTHLY COSTS 19
4.4.1 UTILITIES 19
4.4.2 NON-UTILITY CONSUMABLES 20
4.4.3 LABOR 20
4.4.4 CHEMICAL ANALYSIS 20
4.5 RECURRING PROBLEMS OR ISSUES 20
4.6 REGULATORY COMPLIANCE 20
-------
4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL CONTAMINANT/REAGENT RELEASES
20
4.8 SAFETY RECORD 21
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT . 22
5.1 GROUND WATER 22
5.2 SURFACE WATER 22
5.3 AIR 22
5.4 SOILS 22
5.5 WETLANDS AND SEDIMENTS 23
6.0 RECOMMENDATIONS 24
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 24
6.1.1 SAMPLE RESIDENTIAL WELLS AND SURFACE WATER 24
6.1.2 DELINEATE THE CONTAMINANT PLUME 24
6.1.3 DETERMINE A TARGET CAPTURE ZONE AND CONDUCT A CAPTURE ZONE ANALYSIS ... 25
6.1.4 CONSIDER SAMPLING INFLUENT AND EFFLUENT TO VAPOR PHASE GAC THAT is USED FOR
TREATING VAPORS IN HEAD SPACE OF REACTION TANKS 26
6.2 RECOMMENDATIONS TO REDUCE COSTS 26
6.2.1 REDUCE OPERATOR LABOR 26
6.2.2 ADDRESS REMAINING LAGOON SEDIMENTS AND DISCONTINUE EXTRACTION FROM
LAGOONS ON AN EXPEDITED SCHEDULE 26
6.2.3 CONTINUALLY AIM TO ELIMINATE METALS REMOVAL AND THE UV/OXIDATION SYSTEM
26
6.2.4 OPTIMIZE GROUND WATER MONITORING PROGRAM 27
6.2.5 EVALUATE PROJECT MANAGEMENT/TECHNICAL SUPPORT/REPORTING COSTS 29
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT 29
6.3.1 IMPROVE REPORTING BY INCLUDING UPDATED FIGURES , TECHNICAL ANALYSIS , AND A
SUMMARY 29
6.3.2 TABULATE GROUND WATER MONITORING DATA AND MANAGE DATA ELECTRONICALLY
30
6.4 CONSIDERATIONS FOR A FINAL REMEDY 30
6.4.1 A SUGGESTED APPROACH FOR USING P&T AS A FINAL REMEDY 30
6.4.2 AN ALTERNATIVE TO THE PROPOSED RCRA CAP 31
6.5 SUGGESTED APPROACH TO IMPLEMENTATION 32
7.0 SUMMARY 33
List of Tables
Table 1 -1. Summary of Recent Ground Water Monitoring Results for VOCs
Table 1 -2. Summary of Mean VOC Values
Table 7-1. Cost summary table
List of Figures
Figure 1-1. The Greenwood Chemical Site and Well Locations
Figure 1-2. Extent of VOC Contamination
VI
-------
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 Region 3 is expanding efforts to optimize its Fund-lead remedies. Region 3 requested that
GeoTrans conduct RSEs at two of its Fund-lead P&T systems: Havertown PCP and Greenwood
Chemical. Because GeoTrans has a business relationship with Tetra Tech, the contractor at these two
facilities, Optimization Support Evaluations (OSEs) were conducted in place of the RSEs. The OSE
process is identical to the RSE process, but the name change indicates the business relationship between
GeoTrans and Tetra Tech.
The Remediation System Evaluation (RSE) process (and therefore the OSE 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 Optimization Support Evaluation (OSE) involves a team of expert hydrogeologists and engineers,
independent of the site, conducting an 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. In the case of interim remedies (such as this site), an OSE provides recommendations
that are applicable to the interim remedy and are considerations for a final remedy. 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. For an interim remedy, 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
considerations for a final remedy
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 and represent the opinions of the evaluation team. These recommendations do
not constitute requirements for future action, but rather are provided for the consideration of all site
stakeholders. This OSE report pertains to conditions that existed at the time of the OSE site visit, and
any site activities that have occurred subsequent to the OSE site visit are not reflected in this OSE report.
The Greenwood Chemical site was selected by EPA Region 3 based on the potential to improve the
effectiveness of the remedy to protect human health and the environment and/or to reduce the annual
costs of operating the remedy. 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 OSE consisted of the following individuals:
Peter Rich, Civil and Environmental Engineer, GeoTrans, Inc.
Doug Sutton, Water Resources Engineer, GeoTrans, Inc.
Ken Tyson, Hydrogeologist, GeoTrans, Inc.
The OSE team was accompanied by Kathy Davies and Norm Kulujian from USEPA Region 3.
1.3
DOCUMENTS REVIEWED
Author
EBASCO
USEPA
USEPA
CH2M Hill
Sunil Pereira - CH2M Hill
CH2M Hill
CH2M Hill
Ogden Remediation Services
CH2M Hill
CH2M Hill
CH2M Hill
USEPA
Norfolk District USAGE
Date
8/1990
12/1990
3/24/1994
2/1995
11/28/1995
4/30/1996
7/2/1996
10/1996
10/30/1996
8/20/1997
1/1997
1/23/1998
10/19/1999
Document No./Title
Remedial Investigation
Superfund Record of Decision: Greenwood Chemical,
VA
Explanation of Significant Differences, Greenwood
Chemical Site, Albemarle County, VA
Greenwood Chemical Site Data Acquisition Summary
Report for the Remedial design for Groundwater
Fax Message
Bedrock Monitoring Well and Extraction Well
Installation, Greenwood Chemical Superfund Site,
Newtown, VA
Preliminary Analysis of the Bedrock Aquifer Test
Results, Greenwood Chemical Superfund Site, Newton,
VA
Final Project Report
Greenwood Data from April - June, 1996
Greenwood Chemical Remedial Design WA No. 90-45-
3NP5, Final Design Cost Estimate and Schedule
Final Preliminary Design Report, Interim Groundwater
Treatment Remedy, Operable Unit 2, Greenwood
Chemical Site
Five-Year Review Report, Greenwood Chemical
Superfund Site, Albemarle County, VA
Scope of Work, Line Item 001 1 Wastewater Treatment
Plant Operation, Contract DACW65-98-C-0024,
Engineering During Construction, Greenwood Chemical
Superfund Site, Newtown, VA
-------
Author
USEPA Region III
CH2M Hill
USAGE
USAGE
NA
NA
USAGE
Tetra Tech, Inc
OHM Remediation Services
Corporation
Date
1/18/2000
1/31/2000
6/2001
1/2002
NA
NA
1/23/2003
3-5/2003
9/23/1993
Document No./Title
Memorandum Re: Greenwood Chemical, Addendum:
Revised Ground Water Cleanup Levels
Memorandum - Greenwood Chemical Site OU2 -
Comparison of Proposed O&M Costs Vesus Design Phas
Annual O&M Cost Estimate
Operation and Maintenance Manual, Greenwood
Chemical Superfund Site Groundwater and Lagooon
WastewaterTreatment Facility
OU-4 Focused Feasibility Study Report, Greenwood
Chemical Company Superfund Site, Newton, Albemarle
County, VA
Statement of Work for Operation and maintenance,
Greenwood Chemical Site, Albemarle County, VA
Well Completion Logs (BR-1 through BR-6, OB-1
through OB-8) and Well Completion Diagrams (MW-22,
MW-23,BR-7, andBR-8).
Draft Remedial Action Report for Greenwood Chemical
Superfund Site, OU2 Groundwater and Lagoon, Water
Treatment Facility, Newton, VA
Monthly O&M Reports, February - May 2003
Final Report for Greenwood Chemical Site, Greenwood,
Virginia
1.4
PERSONS CONTACTED
The following individuals associated with the site were present for the visit:
Phil Rotstein - Remedial Project Manager (RPM), USEPA Region 3
Trish Taylor - Community Relations, USEPA Region 3
Chris Quann - OMI
Gary Funkhouser - OMI
In addition, Eric Newman, who replaced Phil Rotstein as the RPM after the OSE site visit, provided
feedback on the draft OSE report during a meeting on February 10, 2004.
1.5
1.5.1
SITE LOCATION, HISTORY, AND CHARACTERISTICS
LOCATION, HISTORY, AND OPERATIONAL DESCRIPTION
The Greenwood Chemical Site ("site") is an inactive chemical manufacturing facility located in
Newtown, Albemarle County, Virginia on VA Route 690 approximately 0.75 miles west of the town of
-------
Greenwood, Virginia and approximately 20 miles west of Charlottesville. The area of the Site associated
with chemical manufacturing and waste disposal activity comprises approximately 18 acres. According
to the 1998 Five Year Review, the entire parcel of land owned by the Greenwood Chemical Company
comprises approximately 34 acres. A site plan that shows current site features and monitoring well
locations is provided in Figure 1-1.
A specialty chemical manufacturing plant operated on the site from approximately 1946 to 1985. Site
features included up to six process buildings and five disposal lagoons. Starting in 1946, Francis O.
Cockerille purchased the property that had formerly been used for agricultural purposes and began
operating a small scale batch chemical manufacturing plant at the Site specializing in pharmaceutical
intermediates. Dye and paint intermediates, plant growth regulators, and photographic chemicals were
also manufactured during plant operations. In April 1985 a toluene vapor leak and fire destroyed one of
the process buildings and led to the death of four plant employees. Manufacturing activities ceased
following the fire although Greenwood Chemical Company continued to operate a small scale chemical
brokerage business at the site for a number of years.
The Site was placed on the National Priorties List (NPL) in 1987 because of potential environmental and
human health risks. These risks were associated with numerous on-site lagoons, pits and trenches used
for the disposal of hazardous substances generated during plant operations. Between 1986 and 1991,
EPA conducted two removal actions that included the removal of drums and smaller containers of
chemicals (both buried and surface), the removal and treatment of some lagoon water and sludges, and
the installation of erosion and sedimentation controls. In August 1990, EPA completed a Remedial
Investigation (RI) for the site to characterize the nature and extent of contamination of soils and/or
sediments, ground water, and surface water associated with the site. These investigations included
geophysical surveying as well as sampling of surface water, ground water (on-site and off-site), soils, and
sediments. They also included collection and analysis of soil boring samples at various depths within the
lagoon and drum disposal areas, installation and sampling of additional monitoring wells, sampling of
residential wells and surface water, and an assessment of hydrogologic conditions.
The site has been divided into four operable units (OUs), as follows.
• OU1 includes contaminated soils associated with seven discrete disposal areas. This remedial
action was completed in the Fall of 1996.
• OU2 includes interim action for contaminated ground water and lagoon water. This interim
remedy is ongoing.
• OUS addresses the dismantlement and off-site disposal of former Process Buildings A, B, and C.
This remedial action was completed in the Spring of 1993.
• OU4 includes surface and subsurface soils other than those addressed in previous OUs plus final
action for ground water. This remedial action will be addressed in an upcoming ROD.
Construction of the P&T system for OU2 began in 1998 and operation began in May 2000. The P&T
system serves as an interim remedy that will operate until a final remedy can be implemented. This
optimization support focuses primarily on this OU2 P&T system but also includes considerations for a
final remedy that will be selected as part of the OU4 ROD.
-------
1.5.2 POTENTIAL SOURCES
The contaminants detected at the site are believed to have originated from poor environmental practices
employed during the forty years of chemical operations at the site. Liquid waste was discharged through
floor drains in the process buildings that drained into unlined pits adjacent to the buildings. Chemical
waste generated by cleaning out process vessels with toluene and other solvents between batch
manufacturing operations were flushed out of the buildings through piping and drainage ditches to the
waste disposal lagoons. Direct spills to the ground occurred during material handling and manufacturing
activities. In addition to these liquid waste disposal practices, drums with hazardous substances were
systematically buried on the plant property.
The primary routes of subsurface discharge and the associated impacted media were the following:
• direct discharge via floor drain leakage beneath the process buildings (soils and ground water
beneath the buildings)
• seepage from the five unlined treatment lagoons (sediments, soils, and ground water beneath the
lagoons)
• overflows from the unlined treatment lagoons (soils and ground water downgradient of the
lagoons)
• discharge from approximately 400 deteriorating buried drums (soils and ground water beneath
the burial pits).
A significant amount of source removal work has been completed at the site. Contaminated soils were
removed from seven discrete disposal areas as part of the remedy for OU1. Contaminant sources
associated with the process buildings (including shallow soils beneath the buildings) were removed
during the implementation of the OU3 remedy. The remaining sources of ground water contamination
include deep soils (i.e., those soils beneath the practical excavation depths achievable during the OU1
and OU3 remedies) and the sediments associated with the remaining treatment lagoons 4 and 5.
The primary constituents of concern at the site (which may be refined as part of the OU4 ROD) are as
follows:
VOCs
Acetone
Benzene
Carbon Tetrachloride
Chlorobenzene
Chloroform
1,4-dichlorobenzene (1,4-DCB)
1,2-dichlorobenzene (1,2-DCB)
1,2-dichloroethane (1,2-DCA)
Methylene Chloride
Cis-1,2-dichlorethene (cis-1,2-DCE)
Tetrachloroethene (PCE)
Trichloroethene (TCE)
Toluene
Vinyl Chloride
-------
SVOCs
Naphthalene
Bis(2-chloroethyl)ether
Metals/Inorganics
Aluminum
Arsenic
Cyanide
Other contaminants, including tentatively identified compounds, are also present at the site.
1.5.3 HYDROGEOLOGIC SETTING
The site is located on the southeastern edge of the Blue Ridge physiographic province and west of the
Piedmont physiographic province. The topography of the Site slopes toward an unnamed tributary of
Stockton Creek in the southeastern portion of the site. Ground water is present in both the overburden
and fractured bedrock aquifers. The saturated thickness of the overburden generally ranges from less
than one foot at MW-11 north of the Drum Disposal Area to about 80 ft at the MW-17 well cluster near
the former northern warehouse. Within the bedrock, ground water is limited to the interstitial spaces
associated with the well-developed bedrock fracture system. There is essentially no intergranular
porosity (or primary porosity) in the bedrock. The vertical extent of this fracture system beneath the site
could not be determined on the basis of the bedrock NX coring that was done for a select suite of the
bedrock wells. The degree of fracturing reportedly decreases significantly below depths of 300 ft below
ground surface (bgs). The resource potential of ground water in the site vicinity is probably limited to
shallower than 300 ft bgs.
The water table at the site occurs in the overburden, at depths varying from less than 5 feet bgs to more
than 35 feet bgs. An exception occurs at well MW-11, where the water table has historically fallen
below the bedrock-overburden contact. The position of the water table surface is largely controlled by
the local topography, which slopes generally to the southeast. Localized variations in permeability have
also created small areas with perched water tables, primarily in the lagoon area and beneath the process
buildings. March 2001 water elevation data from the MW-17 and MW-21 clusters suggest that the
hydraulic gradient in the overburden at the site is relatively steep at approximately 0.07 feet per foot in a
southeasterly direction. The hydraulic gradient in bedrock appears to be approximately 0.02 to 0.03 feet
per foot in a southeasterly direction. In general, the vertical ground water flow patterns are downward
from the overburden into the shallow bedrock in the northern portions of the site near the former process
buildings, and upward in the southern portions of the site where wetlands occur and the water table
intersects the ground surface. Within the bedrock, the overall vertical ground water flow pattern is
upward from the deep to the shallow zones, indicating that the deep fractured bedrock aquifer may be fed
from recharge at higher elevations up-slope from the site.
The hydrogeologic and hydraulic characteristics of both the overburden and bedrock aquifers have been
defined on the basis of extensive testing and evaluation activities completed during the RI and earlier
investigations. The overburden component consists of saturated soil and saprolite material. Ground
water in the overburden occurs primarily in the intergranular pore spaces but can also be found in relict
fractures that were present in the parent bedrock material. Hydraulic conductivity (K) values for the
overburden vary by two orders of magnitude, as shown below. The lowest K values were associated with
wells screened in the upper portion of the overburden. Wells screened just below or across the
weathered rock-overburden contact yielded the maximum K values but in general were highly variable,
ranging from a low of 1.9* 10"5 cm/sec at MW-19 to a high of 4.3x 10"3 cm/sec at MW-11. The chemical
-------
weathering of the Pedlar Formation produces a sandy clay material rich in kaolinite with the sand
fraction consisting of quartz. Coarse gravel and other residual boulders are also present. For a given
profile, the highest permeability should occur near the base of the weathered rock zone, where fracture
apertures are likely to still be open. Also at this level, because of the reduced weathering and chemical
alteration, the saprolite is likely to have sandy texture with little or no clay.
Monitoring Well
MW-1
MW-2S
MW-2D
MW-2D**
MW-3
MW-4
MW-5
MW-7S
MW-7D
MW-10
MW-10D
MW-11*
MW-12S
MW-14S
MW-14S**
MW-14D
MW-16S
MW-16D
MW-17S
MW-19*
MW-20S**
Geometric Mean
Geometric Mean
Unit
OB
OB
OB
OB
OB
OB
OB
OB
OB
OB
OB
Rock
Rock
Rock
Rock
Rock
Rock
Rock
OB
OB
OB
OB
Rock
Well Depth
(ft)
42
36
76
-
40
42
17
19
41
40
59
41
44
108
-
209
72
202
45
46
28
Hydraulic Conductivity (K)
ft/day
1.17
1.37
0.74
0.21
0.40
0.21
0.21
0.27
0.24
0.11
0.05
12.33
7.37
1.17
3.28
0.27
10.45
1.22
0.01
0.05
0.11
0.26
2.75
Note: All results are based on rising or falling head slug tests unless otherwise indicated
* Well is screened just below or across the weathered bedrock and overburden contact
** Data derived from short-term pump test
OB = Overburden well
Rock = Bedrock well
The geometric mean hydraulic conductivities and hydraulic gradients in the overburden and bedrock
combined with a representative porosity suggest a ground water seepage velocity of approximately 0.05
to 0.15 feet per day, with the velocity in the bedrock at the upper end of this range and the velocity in the
overburden at the lower end of this range.
Ground water at the site discharges to ground surface at various seeps along the southern portion of the
property, discharges to West Stream, and/or continues to flow beneath West Stream and further
downgradient. While the existing hydrogeologic characterization of the site is in general quite good, it is
hampered by the fundamental complexity of the bedrock fracture network. As a result, it has not been
possible to conclusively identify discrete primary contaminant flow paths in the bedrock and the fate of
all contaminated ground water at the site.
-------
1.5.4 RECEPTORS
South Pond, East Pond, and West Stream (a tributary to Stockton Creek that runs along the southern
boundary of the site) were receptors of contaminated overland flow, but, as discussed above, previous
removal actions have addressed the sources of contamination to overland flow and have virtually
eliminated this pathway. During the RI, site-related contamination was found in South Pond, but not in
the off-site surface water bodies (i.e., East Pond and West Stream). These surface water bodies,
however, remain potential receptors of contaminated ground water.
Residents in the vicinity of the site rely on private wells to supply potable water for both domestic and
agricultural uses. Approximately 29 supply wells are located within 1 to 2 miles of the site. With one
reported exception northeast of the site (upgradient), all of these wells are completed in the bedrock.
Completion data are not available for most of these wells, but the RI indicates that most of the wells are
completed in bedrock and that the depths typically range from 75 to 250 ft bgs. The RI indicates
approximately 5 private wells that are located downgradient (i.e., southeast of the site). The remaining
wells, although closer to the site are located in upgradient or side-gradient directions. Water quality
monitoring of these wells during the RI did not indicate site-related contamination. Detectable
concentrations of some organic contaminants were found, but these analyses were disqualified due to
laboratory contamination. A detectable concentration of cyanide (14 ug/L) resulted from one sampling
event during the RI but was disqualified based on later sampling with a more appropriate detection limit
(5 ug/L).
Therefore, although there is potential for ground water to contaminate private wells, no conclusive
evidence was found that such contamination had occurred. Sampling of these wells since 1989, if it has
been done, is not well documented.
1.5.5 DESCRIPTION OF GROUND WATER PLUME
The contaminants of concern at the site are primarily VOCs, SVOCs, and metals. The VOC ground
water data from September 2002 through lune 2003 are shown in Tables 1-1 and 1-2 and VOCs are
depicted on Figure 1-2. SVOCs, inorganic compounds, and tentatively identified compounds are not
shown. Ground water quality data are not routinely tabulated as part of the site activities. Tables 1-1 and
1-2 were compiled by the optimization support team to provide the basis for analysis in this report.
These data have been reviewed and are of sufficient quality for use in this report, but the optimization
support team recommends that these data be thoroughly reviewed using a more rigorous QA/QC
protocol.
Table 1-1 provides the water quality data for detectable ground water VOC concentrations from
September 2002 through lune 2003. In order to simplify the depiction of the distribution of these
constituents, the mean VOC totals have been calculated in Table 1-2 and posted on Figure 1-2. Figure 1-
2 shows that the downgradient extent of the constituent plume extends at least as far as MW-21S and that
the exact downgradient plume boundary cannot be determined from these data. Table 1-2 and Figure 1-2
indicate that relatively high VOC concentrations occur at MW-23, MW-18D2, MW-18S, OB-5, and OB-
4.
The extent of cyanide and arsenic impacts is limited compared to the impacts from VOCs. Groundwater
monitoring data collected in four sampling events between September 2002 and lune 2003 indicate that
only three wells had cyanide concentrations above the federal MCL of 200 ug/L, and only five wells had
arsenic impacts above the future arsenic MCL of 10 ug/L. No wells had arsenic concentrations above the
current MCL of 50 ug/L. The extent of aluminum impacts is more difficult to evaluate because there is
-------
no federal MCL or other standard for comparison. For reference, however, approximately 10 wells have
had concentrations of aluminum exceeding 1,000 ug/L, and eight of these 10 wells are in the overburden.
It should be noted that MCLs are used here for reference only. They have not necessarily been chosen as
the cleanup standards for the site. The cleanup standards will be set in the OU4 ROD.
The transport of contaminants vertically into the bedrock likely occurred due to infiltration of the
contaminated water from the lagoons that caused ground water mounding and a downward driving force.
Now that the dissolved contamination from the lagoons has been removed and the water in Lagoons 4
and 5 is managed, this downward driving force is likely no longer present.
-------
2.0 SYSTEM DESCRIPTION
2.1
SYSTEM OVERVIEW
The ground water extraction system recovers ground water from five bedrock extraction wells (BR-2,
BR-6, BR-7, BR-8, and MW-23) that are depicted in Figure 1-1. Each well is piped to the plant
separately with a flow meter on each line. In addition, a floating pump assembly allows for extraction
from Lagoon 5 (Lagoon 4 is hydraulically connected to Lagoon 5) to prevent overflow during
precipitation events. The treatment system provides for metals and solids removal, destruction of organic
contaminants via UV oxidation, and sorption of remaining organic contaminants to GAC. Treated
effluent is discharged to the West Branch of Stockton Creek, located south of the site.
2.2
EXTRACTION SYSTEM
Consistent with the function of an interim remedy, the wells are not specifically positioned for plume
capture. Rather, they are positioned and designed for the purpose of mass removal in the high-
concentration areas of the ground water plume. Information on the extraction system is summarized in
the following table, including average extraction rate and VOC mass removal rate.
Extraction
Well
BR-2
BR-6
BR-7
BR-8
MW-23
Lagoon
Total
Extraction Interval
Top
(ftbgs)
37
52
107
51
94
Bottom
(ftbgs)
77
70
126
112.4
122.8
Total
(ft)
40
18
19
61.4
28.8
Average
Extraction
Rate*
(gpm)
3.7
3.0
2.3
0.5
1.2
0.3
11
Mean Total VOC
Concentration**
(ug/1)
34
644
300
226
2,311
Mass
Removal
Rate
(Ibs/day)
0.002
0.023
0.008
0.001
0.033
% Mass Removed
3.0%
34.3%
11.9%
1.5%
49.3%
512***
0.067
100%
* Average extraction rate is for the operating period of January through May 2003 calculated by taking the total gallons
extracted and dividing by the total time during that 151-day period.
** Indicated concentrations are averages of results from four sampling events between September 2002 and June 2003.
*** This blended concentration accounts for different flow rates from different wells.
As is evident from the above table, the VOC mass removal rate was approximately 0.07 pounds per day
or 26 pounds per year. The majority of this contaminant mass is carbon tetrachloride and chloroform.
Based on data from the same period, removal of inorganics and SVOCs is substantially lower. For
example, metals removal from the extraction wells is approximately 0.002 pounds per day (primarily
aluminum), and removal of cyanide (0.0005 pounds per day) and arsenic (undetectable) is even more
negligible. Based on the average flow rate above and average blended influent concentrations from
February through May 2003, the removal of aluminum is approximately 0.03 pounds per day, with the
increase presumably due to pumping from the lagoon. Also based on the influent data, the removal of
bis(2-chloroethyl)ether is approximately 0.002 pounds per day.
10
-------
2.3 TREATMENT SYSTEM
The treatment plant was designed for a flow rate of 50 gpm and a maximum hydraulic capacity of 60
gpm. The treatment plant consists of the following components for treatment of the extracted ground
water.
• One 12,600 gallon flow equalization tank
Two tanks in series for chemical addition, pH adjustment, and flocculation
One inclined plate clarifier with a sludge thickening compartment, and pumps to both recirculate
and waste sludge
One gravity dual-media filter
One UV oxidation system with hydrogen peroxide addition
Two GAC units in series to remove hydrogen peroxide and organic contaminants not removed by
the UV oxidation system
An effluent/backwash storage tank
One plate-and-frame filter press and sludge holding tank for dewatering solids settled out in the
clarifier
Chemical feed systems including: caustic and sulfuric acid for pH adjustment, ferric chloride for
enhancing iron co-precipitation, polymer for enhancing floe formation, body feed for solids
handling, and hydrogen peroxide for oxidation in the UV system
Instrumentation and electrical panels, including telemonitoring and control systems
A pre-engineered building to house the entire treatment system
The influent is combined in the 12,600-gallon equalization tank. From the equalization tank water is
pumped to the rapid mix and flocculation tank where ferric chloride, caustic, and polymer are added.
The water then flows to a plate clarifier for solids settling and then through three auto-backwashing
gravity filters in series. Following the gravity filters the water flows to a final pH adjustment tank, to the
30 KW UV/Ox unit, and then to two 2,000-pound GAC units in series. Following the GAC units,
process water flows to a final effluent/backwash storage tank and then by gravity to the surface water
outfall (West Branch of Stockton Creek). System sludge is collected in a 4,600 gallon tank and
dewatered with a filter press. System tanks are vented through vapor phase GAC units.
2.4 MONITORING PROGRAM
Treatment process monitoring is conducted monthly at the following locations along the treatment train
for the specified parameters:
11
-------
SL-1: Influent (VOCs, SVOCs, metals)
• SL-2: Clarifier effluent (metals)
SL-3: Filter effluent / UV oxidation influent (VOCs, SVOCs, metals)
SL-4: UV Oxidation effluent / GAC influent (VOCs, SVOCs)
Effluent (VOCs, SVOCs, metals)
Ground water monitoring is conducted monthly at the extraction locations and quarterly at 23 well
locations, including the extraction wells. The wells are sampled for VOCs, SVOCs, and metals.
Periodic sampling might also be conducted at the local residential wells, but this sampling, if it is done, is
not well documented. All samples are shipped to an off-site laboratory for analysis. The process
monitoring data are reported in the O&M Reports, and remaining data are reported in quarterly
monitoring and/or periodic reports.
12
-------
3.0 SYSTEM OBJECTIVES, PERFORMANCE AND CLOSURE
CRITERIA
3.1
CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
According to the OU-2 ROD (1990), the primary objectives of the OU-2 interim remedy are as follows:
initiate the reduction of toxicity, mobility, and volume of ground water contaminants
minimize the migration of the ground water contaminants toward residential wells
obtain information about the response of the aquifer to remediation measures in order to define
ground water cleanup goals that are practicable for the site and a time-frame for meeting those
goals
restore water quality in Lagoons 4 and 5
Because the final ground water cleanup goals (and the time frame for meeting those goals) could not be
determined in time for the issuance of the OU2 ROD, the ground water pump and treat system was
designated as an interim remedy. A ROD selecting the final remedial action for ground water at the site
will be issued in the future to define the ground water cleanup goals and to modify the remedy as
necessary. Based on information provided during the site visit, the final ROD will specify ARARs for
the site. Because the site-specific ARARs have not yet been developed, this report uses for reference the
Federal MCLs and the site-specific risk-based criteria defined in a January 2000 Region 3 memo.
Neither of these reference concentrations will necessarily be the ARARs.
Contaminant
Acetone
Arsenic
Benzene
Bis(2-chloroethyl)ether
Bis(2-ethylhexyl)phthalate
Carbon tetrachloride
4-Chloroaniline
Chlorobenzene
Chloroform
Cyanide
1 ,2-Dichloroethane
Di-n-butyl phthalate
Methylene Chloride
Napthalene
Federal MCLs
(ug/L)
-
10*
5
-
-
5
-
-
-
200
-
-
-
-
Risk-Based Criteria
(ug/L)
172.07
0.01
0.29
-
0.42
-
31.29
27.79
0.12
103.24
0.11
249.95
1.58
10.96
13
-------
Contaminant
Napthaleneacetic Acid
Tetrachloroethene
Tetrahydrofuran
Toluene
Trichloroethene
2,4,6-Trichlorophenol
Xylene
Original ROD
Cleanup Levels
(ug/L)
-
5
-
1,000
5
-
10,000
Revised Cleanup
Levels (Risk-based)
(ug/L)
7.82
0.09
344.14
53.22
0.87
1.08
10,324.29
* effective January 23, 2006
3.2
TREATMENT PLANT OPERATION STANDARDS
The treatment plant discharges to a drainage swale which drains into West Stream, a tributary of
Stockton Creek. In accordance with its National Pollutant Discharge Elimination System (NPDES)
permit, the plant operators are required to sample the effluent on a monthly basis, and the effluent must
meet the following surface water discharge criteria as reported in the Discharge Monitoring Reports for
select compounds.
Contaminant
Discharge Levels
(ug/L)
Inorganic Compounds
Aluminum
Copper
Cyanide (total)
Zinc
87
9.2
7.6
65
Contaminant
Discharge Levels
(ug/L)
Organic Compounds
Benzene
Bis(2-chloroethyl)ether
Carbon tetrachloride
Chlorobenzene
Chloroform
1,2-Dichloroethane
Methylene Chloride
Napthalene
Tetrachloroethene
Toluene
Trichloroethene
77.5
1.4
90.8
21,000
NL
NL
1,600
90.7
NL
256
NL
*NL means not listed
It should be noted that the discharge criteria for many compounds are greater than the MCLs and/or risk-
based criteria. Although the MCLs and the risk-based criteria will not necessarily be the site cleanup
levels, this finding suggests the possibility that the future site cleanup levels will be lower than the
discharge levels.
14
-------
4.0 FINDINGS AND OBSERVATIONS FROM THE OSE SITE VISIT
4.1 FINDINGS
In general, the OSE team found a smoothly operating and well-organized treatment plant. 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. 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
Although water levels from the site monitoring wells are collected and reported on a monthly basis, they
are not used to generate potentiometric surface maps. Therefore, it is difficult to evaluate ground water
flow patterns under current pumping conditions. Water elevation data from the tables in the monthly
reports, however, can be used to provide a preliminary look at the hydraulic gradients at the site. As
stated in Section 1.5.3 of this report, the water levels from March 2001 under pumping conditions
(chosen because none of the monitoring wells were dry) indicate a hydraulic gradient in the overburden
to the southeast with a magnitude of approximately 0.07 feet per foot and in the bedrock to the southeast
at approximately 0.02 to 0.03 feet per foot. These estimates of the horizontal gradients should be
verified, however, by developing and evaluating potentiometric surface maps. The water elevation data
from 2001 also show upward vertical gradients throughout the site.
4.2.2 CAPTURE ZONES
Although one of the goals of this interim remedy is to minimize the migration of site-related
contamination toward residential wells, this interim system is not designed to provide extensive or
complete capture of the plume. Nevertheless, it is useful to evaluate the degree of capture, especially
when considering a final remedy. Much of the information needed to evaluate a capture zone at this site
has been collected, but those data have not been processed, plotted, or analyzed in submitted reports.
At this site, the plume has not been fully delineated and a target capture zone has not been established.
As indicated in Figure 1-2, contamination is present above site-specific standards (and above MCLs) at
MW-21S and MW-21D. Contamination (albeit at low concentrations) is also present in BR-2, which is
an extraction well that marks the furthest downgradient sampling point (in recent sampling events) on the
western side of the property. Many of the deep wells at the site also have contamination with no deeper
wells to provide delineation. MW-7D and MW-21D are examples of such wells. The concentrations at
MW-7D and MW-21D are higher than at MW-7S and MW-21S (respectively), and it is possible that
concentrations below MW-7D and MW-21D might actually increase with depth. The MW-14 cluster,
which is adjacent to the MW-7 cluster, has bedrock wells which are deeper than those of the MW-7
cluster, but the sampling data from the past year (4 quarters) indicate that the MW-14 cluster has not
been sampled.
15
-------
Pumping tests have been conducted at bedrock extraction wells BR-6, BR-7, and BR-8 in 1996 as part of
the design effort. Drawdown was observable in downgradient wells, however, this information is not
sufficient to evaluate capture. First, drawdown in an observation well does not confirm that capture is
provided at that well. Second, the extraction wells are pumped at substantially lower extraction rates
during P&T operation than they were during the pump tests.
A water budget analysis might provide the best preliminary indication of the degree of capture at this
site. The following parameter values are relevant.
• The hydraulic gradient at the site is approximately 0.02 (bedrock) to 0.07 (overburden) feet per
foot. To be conservative, the higher value is used.
• The geometric mean of the hydraulic conductivity is 2.75 feet per day (bedrock) and 0.26 feet per
day (overburden). To be conservative, the higher value is used, especially since the pumping is
occurring within the bedrock.
• The saturated thickness is approximately 50 feet, and the width of the site and known extent of
contamination is approximately 800 feet.
• On average, approximately 1 1 gpm (2,100 ft3 per day) is extracted from the site extraction wells.
Assuming infiltration from precipitation and/or from the underlying formation is accounted for in the
observed hydraulic gradients, the amount of water extracted is equal to the amount of water flowing
through a given cross-section of the aquifer:
Q = KiWb
where K is the hydraulic conductivity, /' is the hydraulic gradient, Wis the width of the cross-section, and
b is the saturated thickness. This equation can be rearranged to solve for the width.
_ _Q ___ 2,100 ft3/day
~ Kib ~ 2.75fdayx 0.07 x 50ft
This result suggests that the width of capture is approximately 220 feet; however, this result is based on a
number of the simplifying assumptions. The above calculation suggests that capture of all ground water
flowing through the site may not be provided, but given the simplifying assumptions that were made,
further analysis is merited.
Potentiometric surface maps generated during pumping conditions would be helpful in evaluating ground
water flow directions toward extraction wells. Such maps have not been generated, however.
Concentration trends in wells downgradient of the expected capture zone can be used to evaluate capture
if sufficient data have been collected to provide a trend. A review of data from quarterly ground water
monitoring from September 2002 through June 2003 suggests increasing concentrations for individual
VOCs in MW-21D. If MW-21D is beyond the capture zone of BR-6, then this increase is a likely
indication that capture is not provided. On the other hand, if MW-21D is within the capture zone of BR-
6, then the increase would indicate that contamination is passing through MW-21D on a path toward BR-
6. Additional data (beyond four quarters) is likely necessary before attempting to establish a trend.
16
-------
Capture is difficult to evaluate, particularly in bedrock aquifers and aquifers with varying hydrogeologic
zones (e.g., overburden and bedrock). A preliminary analysis of site data (a water budget analysis and
preliminary look at concentration trends) suggests that capture may not be complete and that
contamination is potentially migrating downgradient beyond MW-21D and perhaps in other locations.
4.2.3 CONTAMINANT LEVELS
Comparing the ground water monitoring results that are discussed in the 1990 ROD with recent ground
water monitoring results suggests that the contaminant concentrations in site monitoring wells have not
changed substantially since the RI phase. The highest concentrations are found in both the overburden
and bedrock in the former lagoon area. Downgradient of the lagoons, concentrations are approximately
an order of magnitude lower than concentrations in the former lagoon area, but concentrations generally
increase at depth (MW-7D vs. MW-7S and MW-21D vs. MW-21S). The one year of quarterly data
reviewed during this evaluation did not show a significant trend in influent concentrations, though a
significant trend would not necessarily be expected over a one-year period. Influent concentrations,
however, appear similar to the expected concentrations sampled during the design phase in 1996.
Based on the configuration of the plume, the average extraction rate, and the average influent
concentration, it appears that the interim P&T remedy is doing little to restore the aquifer (i.e., extracting
less than 0.1 pounds per day of contaminant mass).
4.3 COMPONENT PERFORMANCE
4.3.1 EXTRACTION SYSTEM WELLS, PUMPS, AND HEADER
Each of the five extraction wells includes a 0.5 horsepower submersible centrifugal pump that can be
controlled both at the well or at the plant, high and low level set points, individual HOPE piping to the
treatment plant, and an electromagnetic flow meter. During the evaluation site visit, the site team did not
reference any problems with fouling or other complications associated with the ground water extraction
system.
The extraction system also includes a floating extraction assembly for Lagoon 5. Lagoons 4 and 5 are
hydraulically connected, and pumping from the floating assembly prevents the lagoons from overflowing
during precipitation events. The ground water extraction data presented in Section 2.2 of this report
suggest that the extraction from the lagoons (approximately 0.3 gpm) only accounts for approximately
3% of the total treatment system influent, but at any one time, the flow rate from the lagoons may be as
high as 9 gpm and may comprise closer to 50% of the total system influent. Extraction from the lagoons
will likely continue until the sediments are excavated or are demonstrated to meet cleanup standards.
4.3.2 EQUALIZATION/INFLUENT TANK AND METALS REMOVAL SYSTEM
Extracted ground water and lagoon water flows into the 12,600-gallon equalization tank before being
pumped to the rapid mix and flocculation tanks. Blended influent samples are collected from the
equalization tank. The tank has both high and low level controls that shut off and restart the extraction
system, respectively.
The metals removal system consists of a rapid mix tank, flocculation tank, clarifier, multimedia gravity
filters, and pH readjustment. Caustic and ferric chloride are added to the rapid mix tank. The pH is
maintained around 8.0 and the ferric chloride addition ranges between 10 mg/L and 70 mg/L with an
17
-------
average of around 25 mg/L. Both caustic and polymer are added to the flocculation tank, and pH in that
tank is maintained at around 8.5. Sludge from the clarifier is removed approximately twice a week. The
effluent from the clarifier is gravity fed through three multimedia filters that are aligned in series. These
filters are backwashed automatically every 4 to 5 hours when extraction is occurring from the lagoons
and every 8 to 10 hours when no extraction is occurring from the lagoons. After the filters, the pH is
readjusted with the addition of sulfuric acid.
The metals removal system, and specifically the rapid mix tank, is the rate-limiting step of the entire
treatment plant. Although the system was designed with a hydraulic capacity of 60 gpm, the maximum
flow rate achievable is actually about 35 gpm due to limited capacity of the metals removal system.
Head space from these tanks is vented through a 1,000-pound vessel of vapor phase GAC that has not
been sampled or replaced since the system began operation in May 2000.
4.3.3
UV/OXIDATION SYSTEM
The UV/Oxidation system includes one 30 kW UV lamp and the addition of approximately 50 mg/L of
hydrogen peroxide. Although this unit is designed to provide the primary removal of organics, the
removal efficiency for carbon tetrachloride, chloroform, 1,2-dichloroethane, and bis(2-chloroethyl)ether
is generally quite low. The following table represents the average removal efficiencies for each of these
compounds over a four month period in 2003.
Contaminant
Carbon tetrachloride
Chloroform
1,2-Dichloroethane
bis(2-chloroethyl)ether
Average Removal Efficiency
(2/2003 - 5/2003)
20%
23%
69%
79%
As is evident from the above table, the majority of the mass of carbon tetrachloride and chloroform is not
removed by the UV/Oxidation system. In fact, during two of the four months more carbon tetrachloride
was removed due to aeration in the equalization and metals removal tanks than was removed by the
UV/Oxidation system. According to design documents, chloroform and 1,2-dichloroethane were not
expected to require treatment, and the relatively low removal efficiencies were expected for both carbon
tetrachloride and bis(2-chloroethyl)ether.
4.3.4
GAC
There are two 2,000-pound GAC units aligned in series. The first unit is used primarily for destruction
of residual peroxide from the UV/Oxidation step, and the second unit is used for removal of organics.
The second unit is replaced approximately every 8 months when the chloroform and carbon tetrachloride
concentrations reach approximately 25 ug/L each. This set concentration is a compromise between
extending the life of the GAC and meeting the discharge requirements. There is no discharge limit for
chloroform, and the discharge limit for carbon tetrachloride is 90.8 ug/L.
18
-------
4.3.5 EFFLUENT TANK AND DISCHARGE
Prior to discharge to surface water under a NPDES permit, the process water empties into an effluent
tank (8,550 gallons) where it can be sampled or returned to the head of the plant. The effluent tank water
also serves to backwash the multimedia filters and the GAC units.
4.3.6 SOLID WASTE HANDLING SYSTEM
The solid waste handling system includes a 6,000-gallon waste tank for collecting backwash waste, a
4,000-gallon sludge holding tank, a filter press, and associated pumps. The filter press has a 10 cubic
foot nominal capacity and dewaters sludge to approximately 35% solids.
4.3.7 SYSTEM CONTROLS
System controls include a programmable logic controller (PLC), a computer, and an autodialer. Over 16
alarms are designed to activate the autodialer.
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
MONTHLY COSTS
The annual O&M costs were reported to be approximately $450,000 per year. A breakdown of the O&M
costs is provided in the following table.
Item Description
Labor: Project management, technical support, and reporting
Labor: Plant operator (two full-time operators)
Labor: Ground water monitoring
Utilities: Electricity
Non-utility consumables (GAC)
Non-utility consumables (UV/Oxidation accessories and chemicals)
Chemical Analysis
Routine maintenance
Discharge fees and waste disposal
Total Estimated Cost
Estimated Cost
$100,000 per year*
$200,000 per year
$50,000 per year**
$35,000 per year
$7,500 per year
$28,000 per year**
N/A***
$25,000 per year**
less than $5,000 per year**
-$450,000
* Estimated by the evaluation team based on other reported costs and approximate total cost.
** Estimated by the evaluation team based on approximate scope and/or professional judgment.
*** Analyses are provided by the Contract Laboratory Program, and costs are not incurred by the site.
4.4.1 UTILITIES
Electricity is the primary utility, and the UV/Oxidation unit comprises approximately half of the
electricity usage. On an average month, approximately 45,000 to 50,000 kWh is used at the site at a cost
of approximately $0.06 per kWh. The UV/Oxidation unit has a 30 kW lamp that operates continuously,
using approximately 21,000 kWh per month. The remaining electrical usage is for extraction and process
pumps, ventilation, and the air compressor for the sludge handling.
19
-------
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS
Non-utility consumables consists of chemical usage, GAC replacement, and accessories for the
UV/Oxidation unit. More than 80% of the cost for chemical usage is likely due to caustic, ferric
chloride, sulfuric acid, and polymer associated with the metals removal. The remainder is for hydrogen
peroxide. GAC replacement costs approximately $5,000 per replacement of a 2,000-pound GAC unit
every 8 months. The accessories for the UV/Oxidation unit cost approximately $8,000 per year.
Therefore, the total cost for operating the UV/Oxidation unit (electricity and accessories) is
approximately $25,000 per year for electricity, accessories, and hydrogen peroxide.
There is no direct charge for discharging the treated water to surface water, and charges for solid waste
disposal are likely low because the waste is classified as non-hazardous.
4.4.3 LABOR
Only the labor costs associated with the two plant operators were provided. The labor costs and scopes
of work associated with project management, reporting, and ground water sampling were not provided
during the site visit because the contractor was not present. Based on the total O&M cost of
approximately $450,000, the costs for the other O&M items, and the scope of the ground water
monitoring program, the evaluation team assumes that project management, technical support, and
reporting might cost $100,000 per year and that ground water monitoring might cost $50,000 per year.
The $100,000 and $50,000 cost estimates by the OSE team, therefore, are not entirely based on scope.
They are largely based on the total O&M cost that was provided.
4.4.4 CHEMICAL ANALYSIS
Chemical analysis is provided by the Contract Laboratory Program. Therefore, the costs are incurred by
EPA but are not directly assigned to the site.
4.5 RECURRING PROBLEMS OR ISSUES
The site team did not highlight any recurring problems or issues associated with O&M.
4.6 REGULATORY COMPLIANCE
The treatment plant regularly meets its discharge criteria.
4.7 TREATMENT PROCESS EXCURSIONS AND UPSETS, ACCIDENTAL
CONTAMINANT/REAGENT RELEASES
No excursions or accidents were reported during the evaluation site visit.
20
-------
4.8 SAFETY RECORD
The site team did not report any accidents or injuries at the site.
21
-------
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
Ground water at the site (and likely downgradient of the site) remains contaminated, and potential
exposure routes to this contamination include using the water for drinking or other purposes, discharge of
water to the surface where direct contact would be possible, and potentially contaminant vapors that may
volatilize and travel through the vadose zone to the surface. The site is currently open space that is
surrounded by fencing. Therefore, drinking contaminated water, direct contact with contaminated water,
and vapor issues should not be a problem within the confines of the site. Off-site, residential supply
wells and West Stream are likely the potential receptors that are at the greatest risk. Sampling of
residential wells and West Stream during the RI did not reveal the presence of site-related contamination,
but a number of years may have passed since this sampling was completed. The most downgradient
wells at the site are contaminated, and the extent of contamination further downgradient of these wells is
not known.
It is understood that this is an interim remedy, but the potential for impacts to receptors demonstrates the
need for evaluation and potential modifications of the interim remedy until a final remedy is selected and
implemented.
5.2 SURFACE WATER
As of the RI, surface water had not been impacted with site-related contamination. However, this
sampling took place approximately 15 years ago. With continued migration of contamination, the
potential still exists for impacts to surface water or to ground water discharging to the surface in seeps.
The original primary threat to surface water contamination (overland flow of contaminated water) has
been eliminated from previous removal actions and maintenance of the water level in the remaining
lagoons.
5.3 AIR
Although site contaminants include VOCs, it is unlikely that above-ground air quality is compromised
because the site and the area downgradient is open space and any vapor contamination that migrates to
the surface would attenuate due to mixing in the atmosphere and exposure to sunlight. Limitations on the
use of space overlying the plume would likely be sufficient at protecting human health and the
environment in the future, if implemented.
5.4 SOILS
Soil contamination is primarily addressed through other operable units at this site. The OSE team
understands that much of the soil contamination has been removed, but that some arsenic contamination
in limited areas may remain as indicated by dead vegetation. Because the site is fenced exposure to this
22
-------
contamination has likely been prohibited. Solutions to remaining contamination could include removing
the surficial contamination or covering the contamination to prevent direct contact. The site team is
suggesting the application of a RCRA subtitle C cap over a 6 to 7 acre area. The OSE provides another,
more cost-effective option in Section 6.4 of this report.
5.5 WETLANDS AND SEDIMENTS
The sediments of many of the lagoons have been excavated and the lagoons have been backfilled. Future
plans include addressing the remaining contamination in Lagoons 4 and 5. This course of action appears
to be protective of human health and the environment.
23
-------
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 RESIDENTIAL WELLS AND SURFACE WATER
Based on the documents reviewed as part of this optimization effort and discussions during the OSE visit,
the OSE team cannot determine the frequency that residential wells and off-site surface water have been
sampled since the RI. It has been more than 15 years since the RI, which is a sufficient amount of time
for substantial contaminant migration to potentially occur. As a result, we recommend that residential
wells (particularly those downgradient of the site), off-site surface water, and on-site seeps be sampled
for both VOCs and inorganics and that this sampling be documented. To be conservative, it may be
worthwhile to sample select residential wells every year or two years. For cost estimating purposes, a
total of 15 residential well samples and 10 surface water samples are assumed on an bi-annual basis (i.e,
every two years). However, this is only an assumption, and the site team may determine more
comprehensive or simplified program. Reviewing site documents and developing a work plan for this
effort might cost $10,000 and collecting samples might cost $8,000 for each event. The data would be
summarized in periodic reports that are further discussed in Section 6.3. It is assumed that the Contract
Laboratory Program will be used for analysis, though it may be prudent to use an alternative (at least for
the first event) that can provide a faster turnaround time. If residential wells are impacted, point-of-entry
treatment systems may be required.
6.1.2 DELINEATE THE CONTAMINANT PLUME
The primary objective of the final remedy should include containment of contaminated ground water so
that further contaminant migration can be prevented. However, before this can be accomplished, the
extent of contamination needs to be determined. Of primary importance is the contamination found at
MW-21S and MW-21D. There are contaminant concentrations at these wells that are above MCLs, and
the concentrations increase with depth. Therefore, the downgradient edge of the plume has not been
determined and the depth of the plume at MW-21D (which is completed to 53 feet bgs) has not been
determined.
We recommend installing additional monitoring wells for delineation. Two clusters of monitoring wells
at three depths should be installed downgradient of MW-21D (perhaps 200 to 400 feet downgradient
depending on accessibility). The shallow and intermediate wells in each of these clusters might be
completed to depths that are comparable to MW-21S and MW-21D. The depths of the deeper wells in
each of the clusters would likely need to be determined in the field, but sampling MW-14D prior to the
drilling event may provide useful information. MW-14D is located approximately 200 feet upgradient of
MW-21D but the elevation of the base of the screen for MW-14D is 140 feet deeper than that of MW-
21D. The data reviewed by the OSE team suggested that MW-14D has not been sampled recently.
Depending on the results from MW-14D, the site team might consider drilling to a depth of 100 to 200
24
-------
feet bgs, using a straddle-packer assembly to isolate and sample various fracture intervals, sending
samples off-site for analysis, and then installing a screen at an appropriate interval. Ideally, these deeper
wells would provide the necessary delineation at depth. The suggested depth of 100 to 150 feet will
hopefully be sufficient. These wells should be sampled for VOCs and inorganics in an attempt to find
the downgradient edge of the plume. We estimate that installing these wells, including a work plan,
oversight, sampling (two events), and a small report, might cost approximately $150,000 to $200,000
depending on the depths of the wells. Future sampling of these wells is discussed in Section 6.2.4 of this
report.
Additional deep wells could be added near the heart of the plume, but at this stage of the remedy, if
contamination is not migrating off-site at depth near MW-21D or the other clusters that are recommended
above, additional deep wells in the heart of the plume are likely not necessary. The OSE team might
recommend adding additional deep delineation wells at the heart of the plume if aquifer restoration were
an immediate goal. However, the OSE team believes that the current focus should be placed on capture.
6.1.3 DETERMINE A TARGET CAPTURE ZONE AND CONDUCT A CAPTURE ZONE ANALYSIS
Once the plume has been delineated near MW-21D, the site team should have enough information to
determine an appropriate target capture zone. Capture at MW-21D may or may not be required,
depending on the outcome of the delineation activities suggested in 6.1.2.
The new wells suggested in Section 6.1.2 should help determine an appropriate target capture zone. In
addition to evaluating capture for the entire site, the site team may wish to evaluate capture near the
plume "hot spot" near MW-23 and the MW-18 cluster. By containing this contamination, it may
eventually allow the downgradient portion of the plume (near the MW-7 and MW-21 clusters) to clean
up. If these downgradient areas eventually reach ARARs, then it may be possible to discontinue the
extraction from BR-6 at that time.
Evaluations such as those discussed in Section 4.2.2 can be used to evaluate capture. Site data can be
reviewed to conduct a more thorough water budget. Ground water elevations can be plotted and
potentiometric surface maps developed to analyze ground water flow directions and interpret capture
zones. All historic water quality data (rather than just the four quarters reviewed as part of this report)
can be used to develop trend analysis in various wells. Ground water modeling and particle tracking
could be used but should be postponed until the above steps are taken and existing data is fully evaluated.
The site team could use hydrogeologists from the EPA Ground Water Forum for assistance. A good
starting point is Elements for Effective Management of Operating Pump and Treat Systems (EPA 542-R-
02-009).
Once the target capture zone has been determined and actual capture has been interpreted, the site team
can determine if additional extraction is needed and how to achieve that additional extraction. Given the
poor productivity of the site extraction wells, additional extraction wells may be required. The costs for
additional extraction wells or redevelopment of the current wells is not provided. The cost for the
capture zone analysis, including development of an appropriate target capture zone, may be as high as
$40,000. Future capture zone analyses and the associated costs are discussed in Section 6.3.1.
25
-------
6.1.4 CONSIDER SAMPLING INFLUENT AND EFFLUENT TO VAPOR PHASE GAC THAT is USED
FOR TREATING VAPORS IN HEAD SPACE OF REACTION TANKS
The plant operators indicated that there is a 1,000-pound vapor phase GAC unit that is used to treat the
contaminant vapors that accumulate in the equalization and reaction tanks. This unit has been in place
since the plant began operating and has not been sampled. If it was deemed important to include this unit
in the original design, it would be prudent to sample the influent and effluent air stream through this unit
once or twice per year with a PID to determine if breakthrough has occurred. This recommendation
could be easily implemented by plant operator at no additional cost.
6.2 RECOMMENDATIONS TO REDUCE COSTS
6.2.1 REDUCE OPERATOR LABOR
Current operator labor includes two full-time operators at a cost of about $200,000 per year. This
amount of labor should not be necessary. Other, similar treatment systems that are not as well designed
or automated require only one full-time operator, with occasional help from a part time technician. The
Selma Pressure Treating Site in Region 9 and the Havertown PCP site in Region 3 are primary examples.
The Greenwood system is very similar to the one found at Groveland Wells in Region 1, and only one
operator is required at that site. The OSE team suggests reducing operator labor to one full-time operator
with part-time support (perhaps 8 hours per week) from a technician. This reduction in labor should
reduce costs by approximately $50,000 per year or more.
6.2.2 ADDRESS REMAINING LAGOON SEDIMENTS AND DISCONTINUE EXTRACTION FROM
LAGOONS ON AN EXPEDITED SCHEDULE
Until the sediments from Lagoons 4 and 5 are fully addressed (i.e., removed, remediated, or determined
clean), pumping from the lagoons will need to continue. This lagoon pumping substantially increases the
amount of solids entering the treatment plant as is evidenced by the increased backwashing frequency
during lagoon pumping. This increased solids means that more solids need to be removed both to meet
discharge standards and to protect the UV/Oxidation system. Because solids removal (particularly the
metals precipitation aspect) requires substantial labor, chemical usage, and disposal, it is expensive and
should be eliminated when possible. Addressing the lagoon sediments, backfilling the lagoons, and
discontinuing the lagoon pumping is the first stage in potentially eliminating metals precipitation and the
associated costs. Filtration alone might be sufficient to meet discharge standards if the lagoon pumping
is discontinued. The costs and cost savings for this recommendation is not quantified.
6.2.3 CONTINUALLY AIM TO ELIMINATE METALS REMOVAL AND THE UV/OXIDATION
SYSTEM
If metals precipitation were not required, labor costs could be further reduced (from those mentioned in
Section 6.2.1) by another $75,000 to $100,000 per year. Other smaller reductions may result from
decreased use of chemicals. Therefore, it is in the best interest of EPA to avoid metals precipitation, if
possible. Currently, metals removal is required for two reasons. The first is to meet discharge standards
for aluminum, and the second is to protect the UV/Oxidation system.
As mentioned above, influent aluminum concentrations will likely decrease when lagoon pumping is
discontinued. Although pumping from other locations (perhaps to enhance capture) might temporarily
increase aluminum concentrations, overtime, these concentrations will likely decrease. This decrease
26
-------
generally results because the oxidative state of the aquifer near the new extraction wells changes,
favoring precipitation of the metals in-situ. The OSE team has witnessed a number of treatment plants
where metals precipitation was originally incorporated but was not necessary after only a few months or
years of operation. The Oconomowoc Electroplating and Claremont Polychemical Sites are examples.
Even if influent aluminum concentrations are above discharge standards, it is possible that metals
precipitation may not be necessary and filtration alone will reduce these concentrations. Filtration does
not have the same labor requirements as metals precipitation, especially when the backwashing is
automated as it is at the Greenwood plant.
Solids removal is often required for UV/Oxidation units because the turbidity associated with the solids
interferes with the associated photochemical reactions. The OSE team has seen treatment plants where
UV/Oxidation systems operated effectively without metals removal, but it is possible that metals removal
may be required at the Greenwood Chemical site for the sole purpose of protecting the UV/Oxidation
unit. For this reason, the OSE team suggests that the site team evaluate the need for the UV/Oxidation
system. Currently, that system provides very little mass removal given the chemicals and energy it needs
to operate. Section 4.3.3 provides a table of the poor removal efficiencies associated with this unit and
shows that the GAC provides the bulk of the mass removal. Even if influent concentrations were to
increase, it is difficult to argue that UV/Oxidation is the appropriate treatment technology for the site.
GAC is currently replaced due to carbon tetrachloride and chloroform breakthrough, but bypassing the
UV/Oxidation system would not likely substantially increase this replacement frequency given that the
removal efficiency for those two contaminants by UV/Oxidation is only about 20%. Eliminating the
UV/Oxidation system would remove another reason for metals precipitation and would also save
approximately $20,000 per year (even after the conservative assumption that the GAC replacement
frequency would double).
The OSE team understands that UV/Oxidation was originally included because of its ability to destroy a
wide range of contaminants and that some unknown chemicals might be present at the site. If the
possibility exists for discontinuing metals precipitation at the site, and protection of the UV/Oxidation
system is the only reason why metals precipitation cannot be eliminated, it would be more cost effective
to further research the constituents in the influent than it wold be to continue with UV/Oxidation.
Furthermore, chloroform and carbon tetrachloride are two primary examples that relying on
UV/Oxidation to treat unknown chemicals is not necessarily protective.
6.2.4 OPTIMIZE GROUND WATER MONITORING PROGRAM
The ground water monitoring program currently consists of quarterly sampling at 23 wells including the
five extraction wells. Although Section 6.1.2 discussed the need for additional sampling locations for
plume delineation, much of the current sampling appears redundant. The OSE team has the following
recommendations with regard to optimizing the monitoring program.
• MW-17S and MW-17D are upgradient wells that have had undetectable concentrations in all
sampling events reviewed as part of this evaluation effort. Given that there are no known
upgradient sources, it is reasonable to eliminate sampling of these two wells or to reduce
sampling to once every year or two years.
MW-10S, MW-10D, OB-4, OB-5, MW-18S, MW-18D1, and MW-18D2 are monitoring wells in
the hot spot. The concentrations in these wells are expected to decrease as contaminant mass is
removed from the subsurface, but as is documented earlier in this report, that mass removal is
exceptionally small. Aquifer restoration, if it does occur, will occur over decades. Furthermore,
water quality monitoring of these points would not be used for evaluating capture. Tracking
27
-------
progress at these wells, therefore, can be accomplished on an annual basis rather than a quarterly
basis. Sampling at these 7 locations should be reduced to annual.
• OB-1 and OB-2 are similar in nature to the seven locations above but are part of a different hot
spot (i.e., the drum disposal area). The sampling at these wells should be reduced to annual.
OB-7, MW-7S, MW-7D, MW-21S, and MW-2ID are in good locations to evaluate capture. OB-
7, MW-7S, and MW-7D should show a continuous decline in concentrations toward background
if capture of upgradient contamination by BR-8 and MW-23 are successful. MW-2 IS and MW-
2 ID should provide insight into capture provided by BR-6. Therefore, sampling at these
locations should continue on a relatively frequent basis, but semi-annual sampling (not quarterly
sampling) is sufficient. If further trend analysis suggests that MW-2 IS and/or MW-2 ID are in
the capture zone of BR-6, then sampling at these locations can be reduced to annual in the future,
and the evaluation of capture could be left to the downgradient wells that are proposed in Section
6.1.2. It should be noted that changes in the extraction system might change the monitoring
wells that are most suitable for evaluating capture.
• MW-4 and MW-6 have undetectable or extremely low concentrations of contaminants and may
be helpful in continuing to evaluate capture from upgradient extraction. Sampling of these wells,
like others useful for evaluating capture can be sampled semi-annually, without losing valuable
information about the site.
• The seven wells recommended in Section 6.1.2 should be added to the monitoring program.
They should be monitored quarterly in the first year and semi-annually thereafter. The two
additional sampling events that would provide quarterly sampling in the first year are included in
the costs of implementing Section 6.1.2.
• Monitoring of the extraction wells could continue quarterly. This sampling does not require
substantial labor since the wells are continuously purged, the data are useful in evaluating what
each well is contributing to the plant influent, and laboratory analysis is provided at no cost to
the site.
• Although no cost savings would result for the site, the site team could consider reducing the
sampled parameters at various wells to VOCs only. Relative to the other classes of contaminants
at the site, VOCs have the highest concentrations relative to federal MCLs (or other potential
reference standards). VOCs are also very mobile in the subsurface. Therefore, for evaluating
capture, analyzing downgradient locations for VOCs would likely should be sufficient. Sampling
for SVOCS and/or inorganics may need to continue at some locations such as the extraction
wells and those monitoring wells where these constituents are a concern.
The above sampling program represents a decrease from approximately 72 monitoring well samples per
year (18 monitoring wells quarterly, excludes extraction wells) to approximately 37 monitoring well
samples per year. This marks a nearly 50% decrease in sampling and should therefore allow a nearly
50% decrease in sampling labor and supplies. If the OSE team estimated cost for current ground water
sampling of $50,000 per year is correct, implementing this recommendation should result in a cost
savings of approximately $20,000 per year or more.
Monitoring of water levels in all site wells should proceed semi-annually. The resulting data should be
used to develop potentiometric surface maps that can be used for analyzing capture and marking potential
changes in ground water flow due to changes in pumping and/or infiltration.
28
-------
6.2.5 EVALUATE PROJECT MANAGEMENT/TECHNICAL SUPPORT/REPORTING COSTS
The OSE team was not provided with project management, technical support, and reporting costs or
general scopes of work for the site. It does appear, however, that the plant operates consistently with
little or no technical problems and that there are few other complications or ongoing evaluations directly
associated with the P&T system. The site team should likely review the scopes of work and costs
associated with project management, technical support, and reporting to determine if there are items that
can be eliminated or optimized to save costs without sacrificing effectiveness. The OSE team hesitates to
include any specific estimates of any immediate potential cost savings associated with this
recommendation. It is hoped, however, that reduced costs can result in one to two years.
6.3 MODIFICATIONS INTENDED FOR TECHNICAL IMPROVEMENT
6.3.1 IMPROVE REPORTING BY INCLUDING UPDATED FIGURES, TECHNICAL ANALYSIS, AND
A SUMMARY
Monthly reports are provided on treatment system operations. These reports include daily logs, process
monitoring data, work summaries, extraction rates, the Discharge Monitoring Reports, various
operational parameters throughout the treatment system, and ground water elevations at site monitoring
wells. This information is important to share, but the reports could be modified to improve readability
and value to EPA. Reporting for the site could be divided into two separate types of reports: monthly
O&M reports and semi-annual or annual ground water reports.
The monthly reports should include information associated with the treatment plant, including the
Discharge Monitoring Reports, process monitoring data, and flow rates. Some text should accompany
these reports to summarize the highlights, such as problems encountered, changes made to the treatment
plant, etc. Treatment plant upsets or discharge exceedances should be highlighted, and actual mass
loading of contaminants to the treatment plant from extracted ground water should be compared to design
specifications, and where possible, treatment efficiencies should be calculated. In addition, tables should
be added that summarize historical process monitoring. The text and tables should draw EPA's attention
to any noteworthy issues.
The ground water monitoring report could be submitted semi-annually in association with each ground
water sampling event. The reports should include tables of water quality data that indicate both current
and historical data. Samples that have concentrations above cleanup levels should be highlighted. The
new data should also be used to develop a plume map similar in nature to Figure 1-2 of this report. The
plume map should include the target capture zone. Water levels should be used to develop
potentiometric surface maps to indicate ground water flow, and if possible, the interpreted capture zone
should be indicated as well. In addition to evaluating capture, these maps could be used to identify data
gaps and present potential locations for piezometers. To augment the evaluation of capture,
concentration trends at key wells expected to be downgradient of the capture zone should be plotted and
included in each semi-annual report. Finally, the semi-annual ground water report should include a
discussion regarding the performance of the remedy relative to its objectives.
For more information on what should be included in reports, the site team is referred to Elements for
Effective Management of Operating Pump and Treat Systems (EPA 542-R-02-009). The estimated cost
of implementing this recommendation is approximately $15,000 in capital costs to develop templates for
figures and tables and $45,000 per year for compiling the reports and providing the necessary data
analysis. However, it appears that the current project management/reporting and ground water sampling
29
-------
costs should accommodate the improved reporting scope without additional funding. In the future, it may
be possible to move from semi-annual to annual reporting. This might reduce the annual cost by
approximately $10,000 per year.
6.3.2 TABULATE GROUND WATER MONITORING DATA AND MANAGE DATA
ELECTRONICALLY
The ground water monitoring data from this site should be managed electronically and tabulated for easy
reference and data analysis. The ground water monitoring data provided to the OSE team was in hard
copy laboratory reports. As a result, the data from each sample and from each event were on a different
page. This made it extremely difficult to evaluate concentration trends in wells and to compare
concentrations from different wells. The OSE team generated a table from four quarters of data that were
provided as part of this optimization effort. This table is provided along with this report and can be used
as a starting point. Although tabulation of data is discussed in Section 6.3.1, this issue is sufficiently
important to mention as a separate item. The cost for implementing this change is already provided in
Section 6.3.1.
6.4 CONSIDERATIONS FOR A FINAL REMEDY
6.4.1 A SUGGESTED APPROACH FOR USING P&T AS A FINAL REMEDY
Cleanup standards have not been developed for the site, but if the risk-based standards that are presented
in Section 3.1 (or similarly low standards) are adopted, it will make it extremely unlikely that the existing
technologies could be used to restore the aquifer to beneficial use in a reasonable time frame (i.e., many
decades). In particular, standards such as 0.29 ug/L for benzene, 0.09 ug/L for PCE, and 0.01 ug/L for
arsenic would be particularly difficult to achieve. An appropriate remedial strategy for this site would
likely involve P&T to provide hydraulic capture and monitoring to demonstrate that capture is adequate.
If a P&T remedy is selected as the final remedy for the site, the following considerations would be
particularly relevant.
The OSE team suggests that a P&T remedy focus on achieving and maintaining cost-effective capture
over the long term. Focusing on mass removal would likely increase overall cost but probably would not
substantially reduce the cleanup time. It may be effective to include extraction wells near the source area
(i.e., near MW-23), but the primary benefit would likely be containment of that source area rather than
mass removal. Containing the source area may allow the downgradient portions of the plume to reach
ARARs faster and allow the possibility of discontinuing pump from some extraction wells.
To help minimize costs over the long term, all efforts should be made to rely on GAC and to avoid metals
precipitation and the use of UV/Oxidation. The monitoring program, project management, and data
analysis should also be streamlined as much as possible. If the system is substantially simplified (i.e.,
rely on filtration and GAC only) it may be possible to reduce total O&M costs to approximately
$200,000 per year. However, the ability to reach this level of simplification is not yet known due to
uncertainties in the result of implementing the other recommendations.
If the site team moves forward with aggressive source removal technologies the best approach might be
the use of targeted pumping events at hot spot wells. Because a treatment system is on site, the extracted
water could be fed into the equalization system and treated at minimal cost. In-situ chemical oxidation
would not likely be beneficial. As has been demonstrated by the UV/Oxidation system, some of the
contaminants with the highest concentrations (i.e., carbon tetrachloride) are quite resistant to oxidation.
30
-------
Bioaugmentation or nano-scale iron injection might address some of the chlorinated compounds, but
would not address other compounds. Air sparging would not be appropriate given the fractured bedrock
environment.
6.4.2 AN ALTERNATIVE TO THE PROPOSED RCRA CAP
During the site visit, EPA indicated that there is a plan to place a RCRA cap across 6 to 7 acres of the site
to reduce exposure to remaining soil contamination and reduce infiltration. This plan might require
approximately $2 million. A better approach would likely be to remove the remaining surface
contamination (which is reportedly approximately 2 acres) or to provide a geotextile fabric and a 3-foot
to 5-foot layer of clean material over the contamination and stabilize it with vegetation or material that is
conducive to anticipated future land uses. The purpose of these efforts would be to prevent direct contact
with soil contamination, and for this purpose, this covering would be as effective as the RCRA cap. The
cost for this approach might be approximately $500,000, an estimated potential savings of approximately
$1.5 million.
With regard to infiltration and other issues, the OSE team provides the following information for
consideration:
• If selection of ARARs and the final remedy suggest that a P&T system will likely operate
indefinitely, there is little reason to prevent infiltration across the site because an effective P&T
system would capture contamination that is leached by infiltration. A RCRA cap would reduce
leaching associated with infiltration of precipitation, but changes in the water table (caused by
infiltration of rain upgradient of the site) might also cause ground water to come into contact
with contaminated soil even if a cap is present.
• A RCRA cap would reduce the amount of infiltration in the area of the plume and therefore the
amount of ground water that requires containment. The RI states that the site receives
approximately 44 inches of precipitation each year. For a 7-acre area, this translates to an influx
rate of approximately 16 gpm, but much less (perhaps about 25%) probably infiltrates to ground
water. Even if all 16 gpm entered the aquifer and required extraction and treatment (which is
unlikely), the overall difference in the cost of operating the P&T system would not likely offset
the extra cost of installing the RCRA cap. Even if differential in the cost of operating the P&T
system with and without the presence of the RCRA cap was $60,000 per year (a conservative
value), it would take approximately 25 years to pay off the RCRA cap. If the comparison is
made considering net present value, the payoff time would be even longer. A more realistic
value for an increase in annual costs due to increased extraction of 16 gpm is likely under
$35,000, which would result in a pay off time for the RCRA cap of 40 years or longer. An
increase in annual costs due to increased extraction of about 4 gpm (25% of 16 gpm) would be
negligible in comparison with the cost of the RCRA cap.
• Construction of this cap will cause substantial sediment runoff issues during construction, and it
would alter the amount of surface runoff in the future. By choosing the alternative approach
suggested above, these environmental problems and the large associated costs can be avoided.
Allowing infiltration to continue will actually help clean soils at the site and transfer remaining
contamination to the ground water for remediation (albeit over a number of years/decades).
The OSE team therefore recommends that the site team better understand the final ground water remedy,
target capture zone, hydraulic requirements for capture, and the various cost implications for either cap
option before proceeding with the RCRA cap.
31
-------
6.5 SUGGESTED APPROACH TO IMPLEMENTATION
Implementation of the recommendations in Section 6.1 are of primary importance and should be
implemented first. Implementation of recommendations in Section 6.2.1, 6.2.2, and Section 6.2.4 should
also be given a relatively high priority as well as Section 6.3.1 and 6.3.2, but not at the expense of the
recommendations in Section 6.1. The recommendations from Section 6.2.3 and 6.2.5 will be somewhat
contingent on the results of implementing other recommendations and should therefore be postponed
until more information is available.
The ideas in Section 6.4 are for consideration and assistance in planning the final remedy. These ideas
should likely be considered prior to developing the ROD for the final remedy, but there are no specific
recommendations to be implemented.
32
-------
7.0 SUMMARY
In general, the OSE team found a smoothly operating well organized treatment plant. 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. These recommendations
have the obvious benefit of being formulated based upon operational data unavailable to the original
designers.
The recommendations to improve effectiveness include sampling at known potential receptors,
delineating the plume, evaluating capture, and the sampling the effluent process air from a vapor GAC
unit that treats the vapors in the head space of the reaction tanks. The recommendations to reduce cost
include reducing operator labor to one full-time operator with minimal support from a part-time
technician, addressing the lagoon sediments in order to reduce solids entering the treatment plant,
continually evaluating the need for metals removal and UV/Oxidation, optimizing the ground water
monitoring program, and evaluating costs associated with project management/technical
support/reporting. The recommendations for technical improvement are directed at improving reporting
and data management. The considerations for the final remedy include a suggested approach for using
P&T and a cost-effective alternative to constructing a 6-7 acre RCRA cap.
Table 7-1 summarizes the costs and cost savings associated with each recommendation. 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.
33
-------
TABLES
34
-------
Table 1-1. Summary of Recent Ground Water Monitoring Results for VOCs (Part 1 of 2)
Monitoring
Well
MCL*
RBC*
Units
BR-2**
BR-6**
BR-7**
BR-8**
MW-23**
OB-1
OB-2
OB-4
OB-5
OB-7
Formation
Screened
Bedrock
Bedrock
Bedrock
Bedrock
Bedrock
Overburden
Overburden
Overburden
Overburden
Overburden
Date
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
6/2003
9/2002
12/2002
3/2002
6/2003
9/2002
12/2002
6/2003
Acetone
_
172.07
ug/L
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
2600
ND
54.0
890.0
120
ND
ND
ND
ND
6.4
J
J
J
Benzene
_
0.29
ug/L
0.27
0.31
0.89
ND
20.0
18.0
16.0
23.0
ND
ND
ND
ND
ND
ND
ND
ND
240.0
190.0
200.0
200.0
2.4
65.0
96.0
120.0
86.0
64.0
310
220
0.64
110.0
46.0
12.0
ND
22.0
18.0
9.7
J
J
J
J
J
J
J
J
Carbon
tetrachloride
5
-
ug/L
6.4
15.0
10.0
30.0
140.0
300.0
180.0
220.0
150.0
250.0
400.0
340.0
40.0
31.0
20.0
20.0
1500.0
2100.0
1900.0
1500.0
ND
ND
1.7
3.9
3.2
ND
ND
ND
ND
640.0
ND
ND
110.0
64.0
47.0
J
J
J
Chloro benzene
_
27.79
ug/L
0.91
2.0
3.1
0.28
91.0
79.0
81.0
120.0
ND
ND
4.1
ND
12.0
6.8
11.0
2.1
230.0
170.0
180.0
160.0
8
77.0
140.0
190.0
150.0
93.0
630
470
2.3
820.0
640.0
590.0
440.0
150.0
130.0
84.0
J
J
J
J
J
J
J
Chloroform
_
ug/L
ND
12.0
11.0
13.0
160.0
150.0
110.0
190.0
8.8
5.7
10
11
11.0
6.1
4.2
5.0
92.0
ND
88.0
100.0
260.0
1110.0
32.0
31.0
ND
ND
ND
ND
ND
74.0
53.0
35
ND
21.0
20.0
12.0
J
J
J
J
1,2-DCB
600
-
ug/L
ND
ND
ND
ND
ND
13.0
13.0
ND
ND
ND
ND
ND
11.0
4.9
6.4
3.8
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
220.0
210.0
240.0
190.0
21.0
0.70
J
J
J
1,2-DCA
_
0.11
ug/L
ND
ND
0.33
ND
50.0
36.0
41.0
51.0
ND
ND
ND
ND
110.0
40.0
60.0
33.0
47.0
ND
38
27
ND
ND
ND
ND
ND
ND
ND
ND
0.78
580.0
340.0
230.0
120.0
88.0
81.0
52.0
J
J
J
J
cis-
1,2-DCE
70
ug/L
ND
ND
ND
0.31
25.0
20.0
20.0
36.0
ND
ND
ND
ND
38.0
4.6
22.0
14
ND
ND
ND
ND
2.7
ND
6.3
7.9
9.3
6.4
ND
ND
ND
ND
ND
ND
ND
20.0
20.0
17
J
J
J
J
J
PCE
_
0.09
ug/L
1.2
1.8
1.9
1.8
13.0
12.0
9.9
16.0
ND
ND
ND
ND
15.0
14.0
11.0
9.4
29.0
30.0
25.0
18
12.0
17.0
16.0
22.0
16.0
9.5
ND
ND
ND
20.0
28.0
27
52
13.0
8.0
6.1
J
J
J
J
J
J
TCE
_
0.87
ug/L
3.1
3.4
3.9
2.6
98.0
62.0
71.0
78.0
ND
ND
ND
ND
100.0
91.0
66.0
74.0
57.0
42.0
42
29
29.0
28.0
28.0
29.0
10.0
8.8
ND
ND
1.1
710.0
920.0
1400.0
2000.0
190.0
140.0
100.0
E
J
Toluene
1,000
-
ug/L
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
1.0
ND
ND
ND
ND
21000.0
17000.0
2.3
1200.0
270.0
13
ND
ND
J
J
VC
2
ug/L
ND
ND
ND
ND
2.0 J
1.7 J
ND
2.6 J
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
50.0 J
45.0 J
39 J
ND
ND
ND
0.68 J
ND indicates sample was "not detected" above a detection limit of 1
J indicates "estimated value"
Values above the cleanup standard are bold
Oug/1
* MCLs and RBCs (risk-based criteria) are provided for reference only. Actual cleanup standards have not been determined.
** Well is used as an extraction well
Table prepared by OSE team. Data should be reviewed thoroughly prior to use in making further site decisions.
-------
Table 1-1. Summary of Recent Ground Water Monitoring Results for VOCs (Part 2 of 2)
Monitoring
Well
MCL*
KBC*
Units
MW-4
MW-6/6R
MW-7S
MW-7D
MW-10
MW-10D
MW-17S
MW-17D
MW-18S
MW-18D1
MW-18D2
MW-21S
MW-21D
Formation
Screened
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Bedrock
Overburden
Bedrock
Bedrock
Overburden
Bedrock
Date
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
6/2003
6/2003
9/2002
12/2002
6/2003
9/2002
12/2002
6/2003
3/2003
6/2003
3/2003
6/2003
9/2002
12/2002
9/2002
12/2002
3/2003
6/2003
9/2002
12/2002
3/2003
6/2003
Acetone
_
172.07
ug/L
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
14.0
ND
ND
ND
ND
ND
ND
Benzene
_
0.29
ug/L
ND
ND
ND
ND
ND
2.7
1.6
3.1
4.5
29.0
23.0
14.0
ND
8.8
ND
ND
ND
ND
ND
39.0
36.0
13.0
16.0
45.0
ND
1.8
0.55
ND
1.3
1.8
2.6
5.2
5.9
J
J
Carbon
tetrachloride
5
-
ug/L
ND
ND
ND
ND
ND
30.0
27.0
41.0
67.0
220.0
190.0
110.0
ND
ND
ND
ND
ND
6.7
ND
10.0
15.0
11.0
28.0
ND
ND
ND
0.35
1.2
7.6
13.0
14.0
J
J
J
Chloro benzene
_
27.79
ug/L
ND
0.3
0.4
ND
ND
22.0
13.0
25.0
32.0
120.0
100.0
77.0
0.33
1100.0
710.0
ND
ND
ND
ND
470.0
370.0
180.0
230.0
570.0
430.0
21.0
4.2
ND
25.0
14.0
22.0
52.0
52.0
J
J
J
Chloroform
_
ug/L
ND
0.32
0.41
1.1
0.78
5.9
5.4
7.9
11.0
29.0
23.0
14.0
ND
ND
ND
ND
ND
67.0
60.0
12.0
9.0
21.0
25.0
4.0
2.6
1.0
2.3
1.5
6.0
12.0
12.0
J
J
J
J
1,2-DCB
600
-
ug/L
ND
ND
ND
ND
ND
5.8
3.7
5.8
ND
22.0
17.0
ND
ND
13
11
ND
ND
84.0
73.0
1.2
35.0
83.0
52.0
12.0
1.1
ND
13.0
4.9
5.2
11.0
ND
J
J
J
1,2-DCA
_
0.11
ug/L
ND
ND
ND
ND
ND
11.0
6.0
13.0
7.5
59.0
48.0
38.0
ND
ND
6.0
ND
ND
ND
ND
680.0
540.0
190.0
230.0
620.0
380.0
13.0
5.8
ND
14.0
3.0
12.0
41.0
36.0
J
cis-
1,2-DCE
70
ug/L
ND
0.43
0.96
1.2
0.87
0.43
ND
0.63
1.1
18.0
18.0
16.0
ND
ND
ND
ND
ND
ND
ND
ND
ND
76.0
97.0
190.0
170.0
17.0
8.8
1.2
18
24.0
9.8
8.7
9.2
J
J
J
J
J
J
J
J
PCE
_
0.09
ug/L
ND
0.62
1.2
1.1
1.0
0.033
0.058
0.78
1.6
6.8
5.8
5.1
19.0
ND
ND
ND
ND
ND
ND
15
16
13.0
23.0
39.0
39.0
37.0
3.2
0.46
22.0
17.0
7.3
7.1
6.7
J
J
J
J
J
J
J
J
J
TCE
_
0.87
ug/L
ND
0.55
0.74
0.87
1.6
6.1
3.7
5.1
8.7
55.0
50.0
35.0
ND
ND
ND
ND
ND
ND
ND
190.0
230.0
140.0
260.0
480.0
420.0
20.0
5.1
0.97
16.0
14.0
43.0
93.0
110.0
J
J
J
J
Toluene
1,000
-
ug/L
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.20
ND
ND
J
VC
2
ug/L
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
8.9 J
11 J
3.5
7.2 J
8.1 J
7.9 J
2.1
0.92 J
ND
1.9 J
3.0
1.5
1.3 J
ND
ND indicates sample was "not detected" above a detection limit of 1.0 ug/1
J indicates "estimated value"
Values above the cleanup standard are bold
'* MCLs and RBCs (risk-based criteria) are provided for reference only. Actual cleanup standards have not been determined.
** Well is used as an extraction well
Table prepared by OSE team. Data should be reviewed thoroughly prior to use in making further site decisions.
-------
Table 1-2. Summary of Total Mean VOC Values
Monitoring
Well
MCL*
RBC*
Units
BR-2"
BR-6"
BR-7"
BR-8"
MW-23"
OB-1
OB-2
OB-4
OB-5
OB-7
MW-4
MW-6
MW-7S
MW-7D
MW-10
MW-10D
MW-17S
MW-17D
MW-18S
MW-18D1
MW-18D2
MW-21S
MW-21D
Formation
Screened
Bedrock
Bedrock
Bedrock
Bedrock
Bedrock
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Overburden
Bedrock
Overburden
Bedrock
Bedrock
Overburden
Bedrock
Acetone
172.07
ua/L
0.5
0.5
0.5
0.5
0.5
0.5
0.5
884.8
252.8
2.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
3.9
0.5
Benzene
0.29
ua/L
0.49
19.25
0.5
0.5
207.50
33.7
91.50
176.9
52.2
16.6
0.5
0.5
3.0
22.0
0.5
4.7
0.5
0.5
37.5
14.5
22.8
1.0
3.9
Carbon
tetrachloride
5
ua/L
15.35
210.00
285.00
27.75
1750.00
0.5
2.33
213.7
73.7
0.5
0.5
41.3
173.3
0.5
0.5
0.5
0.5
3.6
12.5
19.5
0.5
9.0
Chlorobenzen
e
27.79
U2/L
1.57
92.75
1.40
7.98
185.00
42.5
143.25
367.4
622.5
121.3
0.5
0.4
23.0
99.0
0.33
905.0
0.5
0.5
420.0
205.0
500.0
12.7
35.0
Chloroform
ua/L
9.13
152.50
8.88
6.58
70.13
685.0
16.00
0.5
40.6
17.7
0.5
0.7
7.6
22.0
0.5
0.5
0.5
0.5
63.5
10.5
23.0
2.5
7.9
1,2-
Dichlorobenzen
600
ua/L
0.5
6.75
0.5
6.53
0.5
0.5
0.5
0.5
215.0
10.9
0.5
0.5
4.0
13.2
0.5
12.0
0.5
0.5
78.5
18.1
67.5
6.7
5.4
1,2-DCA
0.11
ua/L
0.46
44.50
0.5
60.75
28.13
0.5
0.5
0.6
317.5
73.7
0.5
0.5
9.4
48.3
0.5
3.3
0.5
0.5
610.0
210.0
500.0
8.3
23.0
cis-l,2-DCE
70
ua/L
0.45
25.25
0.5
19.65
0.5
1.6
7.48
0.5
19.0
0.5
0.9
0.7
17.3
0.5
0.5
0.5
0.5
0.5
86.5
180.0
11.3
12.9
PCE
0.09
ua/L
1.68
12.73
0.5
12.35
25.50
14.5
15.88
0.5
31.8
9.0
0.5
1.0
0.6
5.9
19.0
0.5
0.5
0.5
15.5
18.0
39.0
15.7
9.5
TCE
0.87
ua/L
3.25
77.25
0.5
82.75
42.50
28.5
18.95
0.7
1257.5
143.3
0.5
0.9
5.9
46.7
0.5
0.5
0.5
0.5
210.0
200.0
450.0
10.5
65.0
Toluene
1000
ua/L
0.5
0.5
0.5
0.5
0.5
0.8
0.5
12667.4
370.9
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.4
0.5
vc
2
ua/L
0.5
1.70
0.5
0.5
0.5
0.5
0.5
0.5
33.6
0.6
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
10.0
5.4
8.0
1.4
1.6
Total Mean
VOCs
ua/L
34.4
643.7
299.8
226.3
2311.3
827.1
297.9
14100.4
3408.0
488.6
6.0
7.4
96.8
449.2
24.3
963.5
6.0
6.0
1450.1
781.5
1810.3
74.6
174.1
* MCLs and RBCs (risk-based criteria) are provided for reference only. Actual cleanup standards have not been determinei
Listed concentrations are averages of concentrations presented in Table 1-1.
A value of 0.5 ug/L is used for all NDs
Table prepared by OSE team. Data should be reviewed thoroughly prior to use in making farther site decisions.
-------
Table 7-1. Cost Summary Table
Recommendation
6.1.1 Sample Residential
Wells and Surface Water
6.1.2 Delineate the
Contaminant Plume
6.1.3 Determine a Target
Capture Zone and Conduct a
Capture Zone Analysis
6.1.4 Consider Sampling
Influent and Effluent to Vapor
Phase GAC that is used for
Treating Vapors in Head
Space of Reaction Tanks
6.2.1 Reduce Operator Labor
6.2.2 Address Remaining
Lagoon Sediments and
Discontinue Extraction from
Lagoons on an Expedited
Schedule
6.2.3 Continually Aim to
Eliminate Metals Removal
and the UV/Oxidation System
6.2.4 Optimize Ground Water
Monitoring Program
6.2.5 Evaluate Project
Management/Technical
Support/Reporting Costs
6.3.1 Improve Reporting by
Including Updated Figures,
Technical Analysis, and a
Summary
6.3.2 Tabulate Ground Water
Monitoring Data and Manage
Data Electronically
6.4.1 A Suggested Approach
for Using P&T as a Final
Remedy
6.4.2 An Alternative to the
Proposed RCRA Cap
Reason
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Cost
Reduction
Cost
Reduction
Cost
Reduction
Cost
Reduction
Cost
Reduction
Technical
Improvement
Technical
Improvement
Site Closeout
Site Closeout
Additional
Capital
Costs
($)
$10,000
$150,000
to
$200,000
$40,000
$0
$0
Not quantified
$0
$0
Not quantified
$0
$0
Not quantified
($1,500,000)
Estimated
Change in
Annual
Costs
($/yr)
$8,000
$0
$0
$0
($50,000)
Not quantified
possibly
($120,000)
($20,000)
Not quantified
$0
$0
Not quantified
$0
Estimated
Change
In Life-cycle
Costs
($)*
$250,000
$150,000
to
$200,000
$40,000
$0
($1,500,000)
Not quantified
possibly
($3,600,000)
($600,000)
Not quantified
$0
$0
Not quantified
($1,500,000)
Estimated
Change
In Life-cycle
Costs
($)**
$139,000
$150,000
to
$200,000
$40,000
$0
($484,000)
Not quantified
possibly
($1,937,000)
($323,000)
Not quantified
$0
$0
Not quantified
($1,500,000)
Costs in parentheses imply cost reductions.
* assumes 30 years of operation with a discount rate of 0% (i.e., no discounting)
** assumes 30 years of operation with a discount rate of 5% and no discounting in the first year
35
-------
FIGURES
-------
FIGURE 1-1. THE GREENWOOD CHEMICAL SITE AND WELL LOCATIONS.
*
MW-17S
'MW-17D
LEGEND:
MW-11 EXISTING MONITORING
® WELL
MW-23
EXTRACTION WELL
MW-11.
MW-2S
MW-2D'
_MW-10D
MW-10S „ MW-23
»
OB-5
MW-19
' GROUNDWATER
: TREATMENT PLANT
MW-6 MW-13
4s
MW-6R
MW-21D
BMW-16S
MW-16D
:MW-9'
BR-5
200
400
SCALE IN FEET
(Note: This figure is taken from the Overall Site Plan in the Final Preliminary Design Report, CH2M Hill, January 1997).
-------
FIGURE 1-2. EXTENT OF VOC CONTAMINATION.
LEGEND:
MW-11 EXISTING MONITORING
® WELL
MW-23
•
•
o
o
o
EXTRACTION WELL
>1,000 ppb
100 ppb to 1,000 ppb
10 ppb to 100 ppb
<10 ppb
SYMBOLS ARE BASED ON THE SUM
OF THE REPRESENTATIVE
CONCENTRATIONS FOR THE
FOLLOWING CONSTITUENTS:
ACETONE
BENZENE
CARBON TETRACHLORIDE
CHLOROBENZENE
CHLOROFORM
1,2-DICHLOROBENZENE
1,2-DCA
CIS-1.2-DCE
PCE
TCE
TOLUENE
VINYL CHLORIDE
FORMER DRUM
DISPOSAL AREA
THE REPRESENTATIVE CONCENTRATION
FOR EACH CONSTITUENT IS DETERMINED
BY AVERAGING FOUR QUARTERS OF
DATA FROM SEPTEMBER 2002 THROUGH
JUNE 2003. A VALUE OF 0.5 ppb
WAS USED FOR SAMPLES WITH
NON-DETECTS BELOW 1.0 ppb.
200
SCALE IN FEET
(Note: This figure is taken from the Overall Site Plan in the Final
Preliminary Design Report, CH2M Hill, January 1997, and the Overall
Site and Control Plan modified in October 2001, CH2M Hill. Some of the
well locations in these referenced figures conflict with eachother. The well
locations shown here are approximate and shold be verified by a survey.)
EXISTING 3" GRAVEL
CRUSHED STONE ROA
EXISTING CHAIN
LINK FENC
FORMER CHEMICAL
FACILITY
EXISTING
LAGOON 4/«W-18S
18D
EXISTING LAGOON 5
VMW-7S —OB~7
GROUNDWATER
TREATMENT PLANT
400
------- |