Office of Solid Waste and EPA 540-R-10-012
Emergency Response February 2010
(5102G) www.clu-in.org/optimization
Remediation System Evaluation (RSE)
10th Street Superfund Site, OU2
Columbus, Nebraska
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REMEDIATION SYSTEM EVALUATION
10™ STREET SUPERFUND SITE, OU2
COLUMBUS, NEBRASKA
Report of the Remediation System Evaluation
Site Visit Conducted at the 10th Street Superfund Site
May 12, 2009
Final Report
February 16, 2010
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NOTICE
Work described herein was performed by GeoTrans, Inc. (GeoTrans) for the U.S. Environmental
Protection Agency (U.S. E.P.A). Work conducted by GeoTrans, including preparation of this
report, was performed under Work Assignment #48 of EPA contract EP-W-07-078 with Tetra
Tech EM, Inc., Chicago, Illinois. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
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PREFACE
This report was prepared part of a pilot project conducted by the United States Environmental
Protection Agency Office of Superfund Remediation and Technology Innovation (U.S. EPA
OSRTI). The objective of this pilot project is to conduct independent, expert reviews of soil and
ground water remedies with public funding with the purpose of optimizing the remedy for
protectiveness, cost-effectiveness, and sustainability. The project contacts are as follows:
Organization
Key Contact
Contact Information
U.S. EPA Office of Superfund
Remediation and Technology
Innovation
(OSRTI)
Jennifer Hovis
USEPA Headquarters - Potomac Yard
2777 Crystal Drive
Arlington, VA 22202
phone: 703-603-8888
hovis.jennifer@epa.gov
Tetra Tech EM, Inc.
(Contractor to EPA)
Elizabeth Powell
Tetra Tech EM Inc.
1881 Campus Commons Drive, Suite
200
Reston,VA20191
phone: 703-390-0616
Elizabeth.Powell@ttemi.com
GeoTrans, Inc.
(Contractor to Tetra Tech EM,
Inc.)
Doug Sutton
GeoTrans, Inc.
2 Paragon Way
Freehold, NJ 07728
phone: 732-409-0344
dsutton@geotransinc .com
11
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TABLE OF CONTENTS
NOTICE i
PREFACE ii
TABLE OF CONTENTS iii
1.0 INTRODUCTION 1
1.1 PURPOSE 1
1.2 TEAM COMPOSITION 2
1.3 DOCUMENTS REVIEWED 2
1.4 PERSONS CONTACTED 3
1.5 BASIC SITE INFORMATION AND SCOPE OF REVIEW 4
1.5.1 LOCATION 4
1.5.2 SITE HISTORY, POTENTIAL SOURCES, AND RSE SCOPE 4
1.5.3 HYDROGEOLOGIC SETTING 6
1.5.4 POTENTIAL RECEPTORS 7
1.5.5 DESCRIPTION OF GROUND WATER PLUME 8
2.0 SYSTEM DESCRIPTION 9
2.1 GROUND WATER EXTRACTION SYSTEM 9
2.2 GROUND WATER TREATMENT SYSTEM 9
2.3 OTHER REMEDY COMPONENTS 10
2.3.1 AS/SVE SYSTEM 10
2.3.2 ISCO INJECTIONS 12
2.4 MONITORING PROGRAM 12
3.0 SYSTEM OBJECTIVES, PERFORMANCE, AND CLOSURE CRITERIA 14
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA 14
3.2 TREATMENT PLANT OPERATION STANDARDS 15
4.0 FINDINGS 16
4.1 GENERAL FINDINGS 16
4.2 SUB SURFACE PERFORMANCE AND RESPONSE 16
4.2.1 PLUME CAPTURE 16
4.2.2 GROUND WATER CONTAMINANT CONCENTRATIONS 18
4.3 COMPONENT PERFORMANCE 19
4.3.1 GROUND WATER EXTRACTION SYSTEM 19
4.3.2 GET TREATMENT SYSTEM 20
4.3.3 AS/SVE SYSTEM 20
4.3.4 ISCO INJECTIONS 22
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF ANNUAL COSTS 23
4.4.1 UTILITIES 23
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS 24
in
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4.4.3 LABOR 24
4.4.4 CHEMICAL ANALYSIS 25
4.5 APPROXIMATE ENVIRONMENTAL FOOTPRINTS ASSOCIATED WITH REMEDY 25
4.5.1 ENERGY, AIR EMISSIONS, AND GREENHOUSE GASES 25
4.5.2 WATER RESOURCES 26
4.5.3 LAND AND ECOSYSTEMS 27
4.5.4 MATERIALS USAGE AND WASTE DISPOSAL 27
4.6 RECURRING PROBLEMS OR ISSUES 27
4.7 REGULATORY COMPLIANCE 28
4.8 SAFETY RECORD 28
5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN HEALTH AND
THE ENVIRONMENT 29
5.1 GROUND WATER 29
5.2 SURF ACE WATER 30
5.3 AIR 30
5.4 SOIL 30
5.5 WETLANDS AND SEDIMENTS 30
6.0 RECOMMENDATIONS 31
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS 31
6.1.1 EVALUATE THE NEED FOR FURTHER EVALUATION OF POTENTIAL FOR
VAPOR INTRUSION NEAR OHM FACILITY 31
6.1.2 DISCONTINUE PUMPING AT EW-04 AND SHIFT PUMPING WEST TO EW-03 31
6.1.3 ADDRESS CALIBRATION ISSUES WITH THE FLOW MODEL 32
6.1.4 ADDRESS POTENTIAL PLUME MIGRATION TO THE SOUTHEAST
(DELINEATION AND ICs) AND ASSOCIATED POTENTIAL ACTIONS 32
6.2 RECOMMENDATIONS TO REDUCE COSTS 35
6.2.1 DISCONTINUE ISCO AFTER CONTRACT is COMPLETED 35
6.2.2 CONTINUE TO USE PDBs WITHOUT EXTENSIVE COMPARISONS 35
6.2.3 REDUCTIONS IN MONITORING/REPORTING 35
6.2.4 PROJECT MANAGEMENT AND TECHNICAL SUPPORT MOVING FORWARD 37
6.3 RECOMMENDATIONS FOR TECHNICAL IMPROVEMENT 38
6.3.1 MEASURE AND TRACK SPECIFIC CAPACITY OF WELLS 38
6.3.2 CONSIDER VFDs FOR EXTRACTION WELL PUMPS 38
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE Our 38
6.4.1 CONSIDER ALTERNATE ACTIONS AT OHM FACILITY 38
6.5 RECOMMENDATIONS FOR IMPROVED SUSTAINABILITY 40
Tables
Table 4-1. Energy and Atmosphere Footprint Analysis
Table 6-1. Cost Summary Table
Table 6-2. Sustainability Summary Table for Recommendations
IV
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Attachments
Attachment A - Selected Figures from Previous Site Reports
Attachment B - Assumptions for Estimating the Footprints for Various Potential Actions
Described in Section 6.1.4
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1.0 INTRODUCTION
1.1 PURPOSE
During fiscal years 2000 and 2001 independent reviews called Remediation System Evaluations
(RSEs) were conducted at 20 operating Fund-lead pump and treat (P&T) sites (i.e., those sites
with P&T systems funded and managed by Superfund and the States). Due to the opportunities
for system optimization that arose from those RSEs, EPA OSRTI has incorporated RSEs into a
larger post-construction complete strategy for Fund-lead remedies as documented in OSWER
Directive No. 9283.1-25, Action Plan for Ground Water Remedy Optimization. A strong interest
in sustainability has also developed in the private sector and within Federal, State, and Municipal
governments. Consistent with this interest, OSRTI has developed a Green Remediation Primer
(http://cluin.org/greenremediation/) and as a pilot effort now considers green remediation during
independent evaluations.
The RSE process involves a team of expert hydrogeologists and engineers that are independent of
the site, conducting a third-party evaluation of the operating remedy. It is a broad evaluation that
considers the goals of the remedy, site conceptual model, available site data, performance
considerations, protectiveness, cost-effectiveness, closure strategy, and sustainability. The
evaluation includes reviewing site documents, potentially visiting the site for one day, and
compiling a report that includes recommendations in the following categories:
• Protectiveness
• Cost-effectiveness
• Technical improvement
• Site closure
• Sustainability
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
consideration by the Region and other site stakeholders.
The 10th Street Superfund Site was selected by EPA OSRTI based on a nomination from EPA
Region 7. The site is located in Columbus, Nebraska. Ground water contamination consists of
VOCs, primarily PCE, TCE and cis-l,2-Dichloroethene (cis-l,2-DCE). Elevated levels of arsenic
also have been detected in some ground water samples, but arsenic is believed to be naturally
occurring in soils at the site and is not addressed by the remedial actions. There are three active
components of the ground water remedy: 1) a ground water extraction and treatment (GET)
system located in the southern (i.e., downgradient) part of the site; 2) an air sparge/soil vapor
extraction (AS/SVE) system located at the One Hour Martinizing (OHM) source area in the
northern (i.e., upgradient) part of the site; and (3) in situ chemical oxidation (ISCO) treatment at
the OHM source area and also at locations between the OHM source area and the GET system.
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The RSE provides an opportunity for an independent third-party review of these remediation
efforts.
1.2 TEAM COMPOSITION
The RSE team consisted of the following individuals:
Name
Doug Sutton
Rob Greenwald
Affiliation
GeoTrans, Inc.
GeoTrans, Inc.
Phone
732-409-0344
732-409-0344
Email
dsutton@geotransinc.com
rgreenwald@geotransinc.com
In addition, the following individuals from EPA Headquarters participated in the RSE
site visit.
• Jennifer Hovis
• Jennifer Edwards
1.3 DOCUMENTS REVIEWED
The following documents were reviewed. The reader is directed to these documents for
additional site information that is not provided in this report.
• 2008 GET System Annual Performance Summary Report - HGL and COM, April 2009
• 2008 AS/SVE Annual System Performance Summary Report - HGL and CDM, April
2009
• January 2009 GET System Quarterly Report - HGL, April 8, 2009
• October 2008 GET System Quarterly Report - HGL, January 26, 2009
• January 2009 Quarterly Sample Results for the One Hour Martinizing Source Area Air
Sparging/Soil Vapor Extraction System - HGL, April 21, 2009
• October 2008 Quarterly Sample Results for the One Hour Martinizing Source Area Air
Sparging/Soil Vapor Extraction System - January 26, 2009
• Operations and Maintenance Manual, GET System, Revision 2 - Arrowhead, August
2004
• Operations and Maintenance Manual for the OHM Source Area AS/SVE and ART Well
Systems, Revision 2 - HGL and CDM, July 2008
• ISCO Injection Completion Report, Option Year 1 Round 1 - Lee and Ryan, August 11,
2008
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ISCO Injection Completion Report, Base Year Round 1 - Lee and Ryan (no date
provided)
• ISCO Injection Completion Report, Contingent Round, One Hour Martinizing Area -
Lee and Ryan, November 20, 2007
• Post-Injection Monitoring Report for Chemical Oxidant Injection, Round 1 - HGL,
September 19, 2007
• Report on Final Chemical Oxidation Treatability Study Sampling Results for In Situ
Chemical Oxidation Remedial Design - HGL, December 27, 2006
• Removal Assessment, Phase 3 Report - Ecology and Environment, June 2000
• Removal Assessment, Phase 2 Report - Ecology and Environment, September 1999
• Interim Remedial Action Report - EPA Region VII, June 13, 2007
• Revised Remedial Process Optimization Report Air Sparging/Soil Vapor Extraction
System, One Hour Martinizing Source Area - HGL, November 3, 2006
• Draft Treatability Study Report for In Situ Chemical Oxidation Remedial Design - HGL,
August 4, 2006
• Chemox Costs - Word File provided by RPM prior to RSE site Visit
• 10th Street Cost Analysis - PDF file provided by RPM after RSE site visit
• Electric Bills for AS/SVE System - Various months for 2008
• City of Columbus Costs for GET System, 2005-2009 - City of Columbus (Binder)
1.4 PERSONS CONTACTED
The following individuals associated with the site were present for the visit:
Name
Nancy Swyers (RPM)
Charlene Sundermann
Laura Splichal
Marc Schlebusch
Bill Mehnert
Bob Kloke
Chuck Thomerson
Affiliation
U.S. EPA Region 7
NDEQ
COM
COM
Hydrogeologic
City of Columbus
City of Columbus
Phone
913-551-7703
Email
Swvers.nancv(@,epa.gov
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Hydrogeologic Inc. (HGL) is contracted to EPA. CDM Federal Programs Corporation (CDM) is
a subcontractor to HGL. The GET system is currently being operated by the City of Columbus
through a cooperative agreement with EPA, and both HGL and CDM provide engineering
support to the City as needed.
1.5 BASIC SITE INFORMATION AND SCOPE OF REVIEW
1.5.1 LOCATION
The 10th Street Site is located in the City of Columbus in Platte County, Nebraska (see Figure 1.1
from the 2008 GET Annual Report, included in Attachment A of this report). The 10th Street Site
is composed of two operable units (OUs) illustrated on that figure:
• OU1 is located in the southern part of the site including the southern municipal well field
where ground water contamination was originally detected. Initially it was thought that
the ground water contamination detected in this portion of the site originated at two dry
cleaning locations (Liberty Cleaners and Jackson Services) located south of the railroad
tracks (see Figure 1.2 from the 2008 GET Annual Report, included in Attachment A of
this report).
• OU2 is a larger area that is the focus of the combined remedial measures currently
conducted at the site. Ground water sampling conducted after the initial contamination
was detected indicated an extended area of contamination to the north (i.e., upgradient) of
the original investigation. OU2 extends northward to the OHM dry cleaning property.
The site is an area consisting of both commercial and residential land use. The Loup River is
located approximately one-half mile south of the site. The ground water extraction wells and
treatment building associated with the GET system are located in the southern portion of OU2.
Several components of the remedy, including AS/SVE and ISCO injections, are conducted at the
OHM property, which is bordered by 23rd Street to the north, an alley to the south, a fast-food
restaurant to the west, and 25th Avenue to the east.
1.5.2 SITE HISTORY, POTENTIAL SOURCES, AND RSE SCOPE
According to the 2008 GET System Annual Report (April 2009), VOCs were detected in 1983
during a routine sampling event of the City's municipal wells. Follow-up analysis of the
municipal wells also detected elevated TCE concentrations. In April 1987, the site was referred
to EPA for investigation. The 10th Street Site was proposed for the NPL in October 1989 to
provide emergency response, as well as long-term cleanup. The site was placed on the NPL in
August 1990.
Initial investigations focused on the vicinity of the southern municipal well field, and a ROD was
signed for the site in February 1995 consisting of sampling of municipal and monitoring wells
plus institutional controls, plus a contingency for extraction of contaminated ground water with
treated water discharge to the Loup River. Subsequent ground water monitoring by EPA in 1997
to 1998 indicated higher concentrations of PCE and TCE in the northern portion of the existing
monitor well network, and further investigation of soil and ground water to the north revealed that
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significant VOC contamination appeared to originate from the OHM dry cleaning business. In
September 1999 EPA installed additional monitoring wells upgradient of the initial study area.
Through a Fund-Lead removal action, EPA implemented an AS/SVE system at the OHM
property in October 2000, and this system continues to operate (a dry cleaning business also
continues to operate at the OHM site). The AS/SVE system was declared operational and
functional by EPA and NDEQ in 2004.
EPA issued an interim action ROD for OU2 of the 10th Street Site in September 2001 to protect
the southern municipal well field, and it included the following interim remedy elements:
• Extraction of contaminated ground water at municipal well W-l
• Additional extraction of contaminated ground water upgradient of the southern municipal
well field
• Treatment (if necessary) of extracted ground water, with the following discharge options:
the City storm sewer system; the City municipal water treatment system; or potential re-
use
• Continued operation of the AS/SVE system at the OHM source area
The GET system was designed so that effluent would meet the influent requirements for the
City's water treatment plant, so that the water can then be included in the City water supply. If the
City has too much potable water such that storage capacity is exceeded, the treated water from the
GET system can be discharged to surface water via the City storm sewer system. The location of
well EW-03 was modified from the original design so that it would not capture ground water
contamination from a former manufactured gas plant (FMGP) site located in the vicinity.
Construction of the GET system began in September 2003 and was completed in March 2004.
The system began full-scale operation and discharge to the City storm sewer system in April 2004
(with discharge of backwashed water after acid treatments made to the City sanitary sewer), and
the system began providing treated water to the City's south water treatment plant in May 2005.
EPA installed an additional extraction well (EW-04) in July 2005 to extend the capture area of the
GET system to the east. The GET system was declared Operational and Functional (O&F) on
January 11,2006.
EPA issued a final ROD in September 2005 to address site-wide ground water contamination,
which included the following active remedy components:
• Continued operation of the AS/SVE system at the OHM source area
• Continued operation of the GET system
• ISCO upgradient of the GET system to supplement site-wide ground water remediation
In 2006 a treatability study of ISCO was conducted using potassium permanganate (KMnO4)
injections, and subsequently a design package for ISCO injections was developed. Lee & Ryan
Environmental Consulting, Inc. was awarded a contract and had conducted three rounds of ISCO
injections by the end of 2008 at a variety of locations (Liberty Cleaners, "mid-plume", and at the
OHM parking lot). At the time of the RSE visit a fourth round of ISCO was occurring (at Liberty
Cleaners and "mid-plume"), and there were plans to complete the ISCO contract work with 120
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additional injections to be started later in 2009 (some of which would likely occur at the OHM
facility).
This RSE includes a holistic third-party review of overall site remedy.
1.5.3
HYDROGEOLOGIC SETTING
Site reports refer to the following three aquifer horizons:
Aquifer
Designation
shallow aquifer - upper portion
shallow aquifer - lower portion
middle aquifer
Well
Designation
"A" level
"B" level
"C" level
Description
~ 15-20 ft bgs (near water table)
~ 50-60 ft bgs
-95-105 ft bgs
"bgs" = below ground surface
Depth to water is typically on the order of 10 to 15 ft bgs. A clay layer located approximately 65
feet bgs is continuous beneath a portion of the site. The clay varies in thickness depending on
location but is considered a confining layer that separates the shallow and middle aquifers. The
"C" level wells are finished in the middle aquifer just below this clay layer. Site reports indicate
that the middle aquifer consists of sand and gravel units down to bedrock. Note that VOC
impacts are found in all three aquifer horizons.
The most recent potentiometric surface maps provided to the RSE team are from January 2009.
However, the October 2008 event is a more comprehensive event, and potentiometric surface
maps from the October 2008 GET Quarterly Report are included in Attachment A of this report
(for A, B and C level wells). Background flow appears to be to the south towards the Loup River
in all three aquifer horizons. However, the flow system is clearly modified by the extraction
wells. Based on the shape of the plume (discussed later) as well as water level maps from before
the GET system implementation, it appears that background flow is generally to the southeast, but
historical pumping at the southern municipal well field (at rates that existed prior to the remedy)
caused the plume to migrate more to the southwest as it approached the railroad tracks.
Based on the water level maps from October 2008, there appears to be very little vertical head
difference between the A level wells and B level wells, except in the immediate vicinity of
extraction wells. The same appears to be the case between the B and C wells in locations away
from the extraction wells, but there is a significant downward vertical head difference (on the
order of 5 ft) between the B and C wells in the vicinity of EW-02C. Based on site reports
provided to the RSE team the extraction wells are screened as follows:
Extraction Well
EW-01R
EW-02C
EW-03
EW-04
W-l
Screen Interval (ft bgs)
53-73
100-120
52.5-82.5
50.5-70.5
34-59, 79-109, 119-124
Aquifer Horizons Screened
B
C
B
B
B,C
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The following parameter value information was estimated from pump tests, according to reports
provided to the RSE team:
• Shallow aquifer pump test at EW-01R
o T= 17,763 ft2/d
o K = 295 ft/d (appears to assume saturated thickness of 60 ft)
o S = 0.16 (indicative of unconfmed conditions)
• Middle aquifer pump test at EW-02C
o T = 5,399 ft2/d
o K = 77 ft/d (appears to assume saturated thickness of 70 ft)
o S = 0.0018 (indicative of semi-confined to confined conditions)
The RSE team provides the following calculation of ground water velocity in the shallow aquifer,
using approximate values of 0.0015 for hydraulic gradient (based on water level maps) and 0.2
for porosity (estimate for sand):
V = ki/n = 295 ft/d * 0.0015 / 0.2 = 2.2 ft/d * 365 d/yr = ~ 800 ft/yr
The OHM facility is on the order of 5,000 ft from the southern extent of the plume. Thus, the
calculated ground water flow velocity is consistent with a release at the OHM facility serving as
the source of the VOC plume in the shallow aquifer that extends to the City well field.
1.5.4 POTENTIAL RECEPTORS
The City of Columbus southern municipal well field is partially located in the southern portion of
the site. The southern municipal well field consists of seven wells located near the City's south
water treatment plant on 10th Street (W-l, W-2, W-4, W-8, W-l 1, W-12, and W-13). VOCs
have historically been detected in at least five of the seven municipal wells of the southern
municipal well field. W-l pumps as part of the GET remedy, and the others continue to pump for
water supply purposes, though at a lower combined rate than existed prior to the remedy due to
additional wells in other parts of the City that also provide water for public distribution.
Impacted water that is extracted and treated by the GET system is generally discharged into the
City's water treatment plant for subsequent use as water supply within the City's water
distribution system (the treated water from the GET system can optionally be discharged to
surface water via the City storm sewer). The City has one additional area from which it can draw
ground water, municipal well W-15. W-l 5 is located 2.2 miles east of the City.
According to the 2008 GET Annual Report, the Columbus Institutional Control Area (CICA) was
established by the City in 2003 to provide for institutional controls. The CICA is bounded by
Mahood Drive/24th Street on the north, the Loup River on the south, 33rd Avenue on the west,
and 16th Avenue on the east. This ordinance allows existing private wells within CICA to remain
in place if reasonable safeguards are implemented so that there is no unreasonable likelihood of
human contact with the contaminants in the ground water. In addition, this ordinance prohibits the
installation of new water wells within the CICA.
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1.5.5 DESCRIPTION OF GROUND WATER PLUME
The most recent plume maps provided to the RSE team are from January 2009. However, the
October 2008 event is a more comprehensive event, and combined plume extent maps from the
October 2008 GET Quarterly Report are included in Attachment A of this report (for A, B and C
level wells). These maps illustrate the extent of TCE, PCE, and cis-l-2-DCE above ground water
standards in each of the three aquifer horizons. Site reports for the GET system also present more
detailed maps with values posted for each of the three constituents in each of the three aquifers (9
maps), and AS/SVE reports similarly present maps focused on the vicinity of the OHM facility
for each of these three constituents for multiple depth horizons. All of those maps are not
included in this report, but key observations are noted below:
• At the OHM facility there are PCE concentrations exceeding 1,000 ug/L in multiple
locations and at all depth intervals sampled (17-20 ft bgs, 30 ft bgs, and 50 ft bgs). At the
OHM facility the TCE and cis-l,2-DCE concentrations are much lower than the PCE
concentrations.
• In the A wells PCE concentrations above standards extend approximately 1000 ft
downgradient of the OHM facility, but TCE and cis-l,2-DCE concentrations above
standards persist much further to south/southeast suggesting that PCE is degrading to
TCE and subsequently cis-l,2-DCE with distance from the OHM facility. Vinyl chloride
is generally not detectable in ground water, suggesting that the cis-l,2-DCE is not further
O J O " OO O ?
degrading to vinyl chloride.
• There is PCE contamination just north of extraction well EW-03 in the B zone at well
MW-18B (-150 to 300 ug/L) and in the C zone at wells MW-3 IB (-150 to 300 ug/L) and
MW-18C (-50 to 200 ug/L). In this area the PCE concentrations are somewhat higher
than concentrations of TCE and cis-l,2-DCE (such as at the OHM source area).
However, since there does not appear to be a source in this area, the RSE team assumes
the PCE in this area is due to historical transport of VOCs from the OHM facility, and the
gap in PCE currently observed between the OHM source area and this other area further
downgradient is likely due to remedial measures such as the AS/SVE system, and/or due
to Leaky Underground Storage Tank sites present in the northern portion of the site
(particularly at the Emerson School) that have likely provided a carbon source that has
contributed to the degradation of PCE in this area.
• The plume shape as it approaches the railroad tracks (and further south) likely reflects the
historical impact on flow directions from pre-remedy pumping at the City wells. Since
much of the City well field pumping has now been replaced by pumping at the GET
extraction wells and other supply wells, the flow directions have changed relative to those
that existed when the plume originally migrated to the City wells. An example of a pre-
remedy water level map is included in Attachment A.
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2.0 SYSTEM DESCRIPTION
There are three active components of the ground water remedy:
• The GET system located in the southern (i.e., downgradient) part of the site
• The AS/SVE system located at the One Hour Martinizing (OHM) source area located in the
northern (i.e., upgradient) part of the site
• ISCO treatment at the OHM source area and also at locations between the OHM source area and
the GET system
Details regarding these components of the remedy are provided below.
2.1 GROUND WATER EXTRACTION SYSTEM
The ground water extraction system consists of the following wells (locations are illustrated on Figure 1.2
from the 2008 GET Annual Report, included in Attachment A of this report):
. EW-OlR(lOHPpump)
. EW-02C (30 HP pump)
. EW-03(10HPpump)
. EW-04 (added in July 2005, 10 HP pump)
• municipal well W-l (50 HP pump)
These wells were designed to pump a combined 1,400 gpm (with a design maximum rate of 1,820 gpm).
The well vaults for the EW wells are designed to extend significantly above ground surface
(approximately five feet) per Nebraska Department of Human Health System (NDHHS) regulation. The
pumps are constant speed pumps that are controlled by throttling back a gate valve in the well vault.
Pumping rates are monitored via magnetic signal flow meters (paddle wheel). There is a float valve in the
control vault that will trigger a high-level alarm at the treatment plant (via fiber optic cable). HOPE
piping brings the water to the treatment plant.
2.2 GROUND WATER TREATMENT SYSTEM
A simple process flow diagram of the treatment system (from the 2008 GET Annual Report) is included
in Attachment A of this report. The treatment plant consists of the following components:
• A phosphate-type dispersant (AQ-5010 was the name provided during the RSE site visit) is added
to water entering the treatment plant (via chemical metering pump CMP-1). This is intended to
prevent iron and manganese fouling of the air stripper. The water then enters a 12,000 gallon
influent tank.
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• Water is transferred to the air stripper via a feed pump (50 HP) controlled with a variable
frequency drive (VFD) set at a frequency of 54 Hz. The system originally included bag filters
before the air stripper, but after the initial startup period the turbidity levels decreased to the
point that the bag filters were not needed, and they were subsequently taken off-line. There is a
magnetic flowmeter (paddle wheel) prior to the air stripper.
• The air stripper is a packed column design (Jaeger 3.5-inch tripack). It utilizes a 20 HP blower.
• Acid washing of the air stripper utilizes a 15 HP pump, and occurs approximately every 3 months
(requires approximately 3 days).
• Treated water is discharged to either the City's south water treatment plant (across the street from
the GET plant) via a pump (50 HP) controlled with a VFD (set at a frequency of 36 Hz) through a
12-inch line, or to the City storm sewer system via gravity flow if potable demand is exceeded.
Water that is discharged to the City's south water treatment plant is blended with other water
pumped from the southern municipal well field, which is then treated by the City by adding
fluoride, chlorination, and a sequestering agent for copper. That water is then used for public
water supply. There are plans for a new City water treatment plant to replace the south water
treatment plant, to be constructed next to the GET treatment plant.
• Controls include an Allen-Bradley PLC connected to a computer, which connects via Ethernet to
the GET system building control panel and via fiber optic cable to the extraction well control
panel. The PLC also has a connection to the City's SCADA system.
2.3 OTHER REMEDY COMPONENTS
2.3.1 AS/SVE SYSTEM
The AS/SVE system is located at the OHM source area. A pilot-scale system was installed in April 2000
and operated in May 2000. The full-scale system was installed in July through September 2000. Figures
from the 2008 AS/SVE Annual Report are included in Attachment A that illustrate the process flow
diagram for the AS/SVE system, the locations of the wells, and a cross-section illustrating the shallow
clay and underlying sand (and typical screen interval of the various types of wells).
The intent of the AS/SVE system is to inject air into the saturated zone, which should strip VOCs from
the ground water as the air percolates upward to the unsaturated zone, where the vapors are removed and
treated. This system consists of the following wells for injection and extraction of air:
• 46 vertical clay vapor extraction (CVE) wells (screened approximately 2-7 ft bgs) combined with
the 3 horizontal extraction wells (approximately 5-10 ft bgs) intended to remove VOCs from the
shallow clay layer.
• 9 vertical sand vapor extraction (SVE) wells (screen approximately 7-20 ft bgs) intended to
contain the injected air from sparge wells, and to remove VOCs from the sand underlying the clay
(as well as from the water table). Because the SVE wells are screened across the ground water
table, they are also used to measure ground water levels and concentrations.
• 26 air sparging wells with 5-ft screens (generally screened from 65 to 70 ft bgs).
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• 7 combined injection and extraction well clusters (PCIX and CIX). The PCIX-1 and PCIX-2 well
clusters each consist of one sparging well screened at 70 feet bgs, one SVE well screened at 18
feet bgs, and two monitoring points at 30 feet bgs and 50 feet bgs. The PCIX-5 well cluster
consists of one sparging well screened at 70 feet bgs and three monitoring points (18 feet bgs, 30
feet bgs, and 50 feet bgs). PCIX-3 and PCIX-4 consist of four monitoring points only with no
sparging or SVE. The two CIX wells each have four screened intervals, with the deepest (70 ft
bgs) used for air sparging.
• The Accelerated Remediation Technology (ART) well was pilot tested at the OHM source area as
a remediation well to enhance the effectiveness of the AS/SVE system. The ART system is a
proprietary in-well remediation system that combines in-situ air stripping, sparging, and water
circulation (water comes in the bottom and out the top). It also promotes recirculation of
permanganate as a side-benefit, but this was not the primary purpose. The ART well was
installed at a depth of approximately 65.5 feet bgs with a screened interval from 12-65 ft bgs.
The treatment building adjacent to the OHM facility includes the following equipment:
• Two compressors (50 HP each) for the air sparging system (for the sparge, PCIX, CIX, and ART
wells). Only one compressor operates at a time. Air flows through an air dryer system before
entering the sparge piping. An oil water separator collects a mixture of oil and water from this
compressor air stream. The separated oil is collected for disposal, and the water is discharged to
the City of Columbus sanitary sewer system.
• Blowers consisting of high vacuum system (for the CVE wells and the ART well) and a low
vacuum system (for the SVE, PCIX, and CIX wells).
o The high vacuum system consists of a liquid/vapor separator (knockout tank), blower,
and a heat exchanger. The blower is 75 HP. An AMT pump transfers the water from the
separator to the liquid phase carbon system.
o The low vacuum system consists of a liquid/vapor separator (knockout tank) and two
regenerative blowers. Each of the two blowers is 10 HP, and only one blower operates at
a time. An AMT pump transfers the water from the separator to the liquid phase carbon
system. The low vacuum system is used for wells screened in the more permeable sand,
and the low vacuum also reduces water entrainment because the SVE wells are screened
across the water table.
• Liquid-phase GAC to treat condensate from the two knockout tanks (two 200-pound vessels in
series), which is then discharged through the City sanitary sewer system.
• Vapor-phase GAC with three 5,000-pound vapor-phase GAC vessels (two in series to treat the air
stream from the high vacuum system, and one vessel to treats the air stream from the low vacuum
system).
The AS/SVE has operated inconsistently for the last few years for a variety of reasons (discussed in
Section 4 of this report).
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2.3.2 ISCO INJECTIONS
The locations of the ISCO injections completed prior to the RSE site visit are summarized below:
• Mid-Plume Injections
o The first round (January to May 2007) was on 20th Street between 22nd Avenue and 24th
Avenue. It included 68 locations (10 ft spacing) with potassium permanganate
continuously injected into three intervals (65-49 ft bgs, 48-32 ft bgs, and 31-15 ft bgs).
Approximately 275 pounds of potassium permanganate was injected per location.
o The second round (August to September 2007) was on 16th Street between 20th Avenue
and 22nd Avenue. It included 59 locations (10 ft spacing) with potassium permanganate
injected into two intervals (65-40 ft bgs and 40-15 ft bgs). Approximately 275 pounds of
potassium permanganate was injected per location.
o The third round (September to October 2008) included 70 injections (10 ft spacing) with
potassium permanganate injected in two intervals (65-40 ft bgs and 40-15 ft bgs) in the
following areas: Liberty Cleaners parking lot on 10th Street (20 points), and the
intersection of 20th Street and 22nd Avenue (22 points). Approximately 275 pounds of
potassium permanganate was injected per location.
• OHM Facility Injections
o The first round (September to October 2007) included 50 locations with potassium
permanganate continuously injected into three intervals (65-50 ft bgs, 50-35 ft bgs, and
35-15 ft bgs). Approximately 19,250 pounds of potassium permanganate were injected.
o The second round (May to luly 2008) included 72 locations with potassium
permanganate continuously injected into two intervals (65-40 ft bgs and 40-15 ft bgs).
Approximately 19,800 pounds of potassium permanganate were injected.
o The third round (September to October 2008) included 28 locations with potassium
permanganate continuously injected in two intervals (65-40 ft bgs and 40-15 ft bgs).
Approximately 7,700 pounds of potassium permanganate were injected.
At the time of the RSE visit a fourth round of ISCO was occurring (20 injections at Liberty Cleaners
south of the GET extraction wells and 52 "mid-plume" injections on 20th street), and there were plans to
complete the ISCO contract work with 120 additional injections to be started later in 2009 (locations to be
determined, though it was stated during the RSE site visit that some of these locations would be at the
OHM facility).
2.4 MONITORING PROGRAM
Monitoring at the site includes the following:
• There are 91 site-wide monitoring wells that are sampled annually, along with 11 Former
Manufactured Gasification Plant (FMGP) wells, and two treatability study (TS) wells that are
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sampled to provide additional data in the vicinity of the Columbus FMGP. All of the FMGP wells
and TS study wells are sampled quarterly, along with approximately 50 of the site-wide
monitoring wells. There are an additional 25 wells at the OHM facility that are sampled quarterly.
The OHM well list is the same regardless of whether it is an annual or quarterly event. Thus, the
total number of wells sampled annually is 129. The approximate number of wells sampled during
the other three quarters is 88 per quarter. Wells sampled annually are sampled in October, so
results for October events represent the most comprehensive ground water sampling. Analysis is
for VOCs. Results for many wells are reported in the GET system reports, but results for some
of the wells located near the OHM site are reported in the AS/SVE reports.
• For GET system "process monitoring", quarterly sampling of water is performed at the 14
locations with analysis for VOCs:
o 5 GET extraction wells (including City well W-l)
o 6 additional City wells
o GET influent
o GET effluent
o City water distribution sample
• For the AS/SVE system, "process monitoring" includes quarterly air sampling for VOCs
collected from the influent and effluent vapor-phase GAC adsorption treatment vessels via
summa canisters, for the low vacuum and high vacuum systems (i.e., 4 samples per quarter, plus a
field blank), and also includes one liquid carbon effluent sample each quarter to monitor
discharge to the City sanitary sewer system and determine when liquid-phase carbon change out
is required.
• For the ISCO injections, "process monitoring" for the early injection rounds included some
ground water samples from direct push borings analyzed for VOCs. However, current
monitoring of the ISCO effectiveness is performed with the site-wide ground water monitoring
program.
Passive diffusion bags (PDB) have been implemented at some of the ground water monitoring locations
where there is no dedicated pump. Additional monitoring has been performed to compare results of the
PDB samples to results using pumps. The comparison has been favorable in most cases but not favorable
in a few cases.
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3.0 SYSTEM OBJECTIVES, PERFORMANCE, AND
CLOSURE CRITERIA
3.1 CURRENT SYSTEM OBJECTIVES AND CLOSURE CRITERIA
The goals of the selected remedy in the 2005 ROD include the following:
• Prevent human exposure to contaminated ground water and soil
• Ensure protection of the City's southern municipal well field
• Further reduce contaminant concentrations at the OHM source area
• Reduce the highest ground water contaminant concentrations using a treatment that does not
require intensive operation and maintenance
The remedial action objectives (RAOs) for OU2 are to:
• Control migration of soil contaminants into ground water
• Reduce risks associated with PCE and TCE in soil at source areas
• Reduce concentrations of PCE and TCE in ground water at the source areas and the core
contamination of the ground water plume north of the GET system extraction wells
• Intercept and control the migration of the ground water contaminant plume
• Prevent domestic exposures to private drinking water wells within the ground water contaminant
plume
• Prevent the development and use of the three source properties for residential housing, schools,
child care facilities, and playgrounds
• Restrict the construction or installation of any new water wells on the three source properties to
ground water monitoring wells or remediation wells
• Prevent the excavation of soils on OHM property except by prior written approval from EPA and
NDEQ and ensure that any excavations are conducted in accordance with appropriate worker
protection and soil disposal requirements
According to the 2008 GET annual report, EPA has adopted the following remediation goals:
• 60 micrograms per kilogram (ug/kg) for PCE in soil at the OHM source area
• 60 ug/kg for TCE in soil at the OHM source area
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• 5 ug/L for PCE in ground water
• 5 ug/L for TCE in ground water
• 70 ug/L for cis-l,2-dichloroethene (cis-l,2-DCE) in ground water
The ground water criteria are consistent with federal MCLs, which are the cleanup goals stated in the
ROD.
3.2 TREATMENT PLANT OPERATION STANDARDS
For the GET system, the Nebraska drinking water standards are the basis for the effluent limits (these
standards are located in a table of Title 118, Chapter 4, Narrative and Numerical Standards). The
pertinent limits are:
• 5 ug/L for PCE
• 5 ug/L for TCE
• 70ug/Lforcis-l,2-DCE
• 100 ug/L for trans-1,2-DCE
• 2 ug/L for vinyl chloride
There is also a limit for maximum pH of 9 for the effluent from the GET system.
For the AS/SVE system, the influent and effluent from the vapor carbon units is monitored and provides
data for calculating mass removal. However, the RSE team has not seen reference to standards or permit
values for the effluent air in the site reports it has reviewed.
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4.0 FINDINGS
4.1 GENERAL FINDINGS
The observations provided below are not intended to imply a deficiency in the work of the system
designers, system operators, or site managers but are offered as constructive suggestions in the best
interest of the EPA and the public. These observations have the benefit of being formulated based upon
operational data unavailable to the original designers. Furthermore, it is likely that site conditions and
general knowledge of ground water remediation have changed over time.
4.2 SUBSURFACE PERFORMANCE AND RESPONSE
4.2.1 PLUME CAPTURE
The RSE team reviewed several different types of capture zone evaluations provided in site documents:
• The 2008 GET Annual Report discusses hydraulic containment based on results of previous
simulation modeling, and also presents a summary of a recent modeling update.
• The GET quarterly reports discuss hydraulic containment with regard to head difference pairs that
were selected based on previous modeling efforts, and they conclude that many of these paired
locations show that inward flow predicted by modeling is not actually achieved in the A and B
zones based on observed water levels.
The RSE team has serious reservations regarding the effectiveness of the present system to achieve
hydraulic containment in the A and B zones, and also has serious reservations about the predictive
capability of the current model. Some of these concerns were raised in the latest site modeling report
(Appendix D of the 2008 GET System Annual Performance Report, April 2009) which identified that full
capture is not occurring in the area between EW-03 and EW-04, and that contaminant migration continues
between these wells to the southeast. That modeling report further identified that pumping rate increases
at EW-03 and EW-04, or installation of an additional well is needed to address this issue, and that current
pumping rates are maintained to prevent drawing in nonstrippable ground water contaminants associated
with the Columbus FMGP and Deyke and Pollard Oil sites.
Specific observations by the RSE team regarding plume capture include the following:
• The analyses of head differences presented in the quarterly reports clearly illustrate that the
observed conditions do not match the simulated conditions. This suggests the modeling results
are not accurate. This model limitation was also identified in the April 2009 modeling report.
• This potential lack of model accuracy is further confirmed by comparing the potentiometric
surface maps for the A and B zones (e.g., for October 2008 presented in Attachment A of this
report) with the particle tracking results presented in Appendix D of the 2008 GET Annual
Report (one example of particle tracking is provided in Attachment A). The predicted particle
tracks from the modeling suggest flow patterns that do not match the observed conditions.
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Examples include the following:
o The modeling suggests that flow south of W-l is from the Loup River north towards W-
1, whereas the actual potentiometric surface maps indicate flow in that area is to the
southeast away from W-l. The modeling report also indicated some issues with the flow
model calibration in this area.
o The modeling suggests that water flowing through a gap in capture between EW-03 and
EW-04 generally then flows west towards EW-01R, whereas the actual potentiometric
surface maps suggest flow through this gap will then be to the south or southeast away
fromEW-OlR.
• The model calibration hydrographs presented as part of Appendix D in the 2008 GET annual
report clearly illustrate that the model predicts water levels that are too low at most of the
observation wells after 2006 (one example is presented in Attachment A). Also, at critical
locations near extraction wells the simulated versus observed head differences do not match well,
suggesting the predictions of drawdown due to pumping may not be accurate (examples include
MW-18B to MW-15B and MW-32A to MW-37A). The match of simulated versus observed
conditions is generally better in the initial time period close to the system startup (i.e., 2004 to
2006).
As discussed later in Section 4.2.2, increasing VOC concentrations have been observed at the MW-202
and MW-203 clusters, located in the gap between EW-03 and EW-04. The particle traces from the
modeling suggest that this could occur, but also suggest that much of this water will ultimately be
captured to the west by EW-01R. However, observed flow patterns from actual water level
measurements illustrated on site potentiometric surface maps suggest that water flowing through a gap
between EW-03 and EW-04 will continue flowing to the south or southeast and will not be captured.
The site team indicated during the RSE site visit that a gap in capture between EW-03 and EW-04 was
planned from the outset because of a desire not to pull in ground water impacted by the Dykes and Pollard
oil sites that are located between these extraction wells. Ground water impacts from those sites include
BTEX compounds and PAH compounds, and there is concern that these compounds (particularly the
PAHs) could impact the GET treatment operations. Nevertheless, EW-04 seems to be poorly located.
The plume maps presented in Attachment A of this report indicate that EW-04 pumps water that is not
very impacted, and in fact all VOCs have been below criteria at EW-04 since April 2008. The RSE team
believes that, had EW-04 been located a few blocks north of the Dykes and Pollard oil sites (rather than a
few blocks east), it would have provided much more effective capture. Unfortunately, the current
location of EW-04 provides little benefit, and may actually make it more likely that impacted water flows
beyond the capture zone of EW-03.
With respect to the potentiometric surfaces presented in site reports, the RSE team notes that there are
some locations where no cone of depression is indicated near an extraction well where one likely exists
(e.g., near EW-03 in the A and B zones and near EW-04 in the B zone). This is due to lack of
measurement points in the vicinity of the extraction wells (the site team correctly does not use water
levels measured at the extraction wells). As per "A Systematic Approach for Evaluation of Capture
Zones at Pump and Treat Systems" (EPA 600/R-08/003, January 2008) EPA recommends installation of
water level measurement points near extraction wells to address this issue (these points need not also be
monitored for water quality).
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4.2.2 GROUND WATER CONTAMINANT CONCENTRATIONS
Evaluating concentration trends over time at this site is complex due to a variety of factors:
• There are multiple aquifer zones, with varying degree of connection in different locations (i.e.,
the C zone appears to be in poor connection with the overlying A and B zones near EW-02C and
to the south, but appears to be better connected to the north as evidenced by ground water impacts
observed in the C zone between the OHM facility and the railroad tracks).
• Multiple remediation technologies have been employed in different locations and at different
times (AS/SVE, GET, ISCO)
• There appears to have been a significant change in ground water flow direction over time that is
related to change in pumping patterns at the City's southern municipal well field. Previous site
reports illustrate that before the year 2000 the southern municipal well field caused flow near the
railroad tracks to bend to the west towards the southern municipal well field, rather than follow
the natural flow direction that is to the southeast. This explained the shape of the contaminant
plume. However, when pumping at the City well field was cut back, flow directions shifted to a
more southeasterly direction, as illustrated on more recent potentiometric surface maps.
The RSE team provides the following observations regarding concentration trends:
• There continue to be ground water impacts emanating from the OHM facility, but these impacts
are greatly reduced compared to pre-remedy impacts. For instance, PCE concentrations up to
49,000 ug/L and TCE concentrations up to 6,400 ug/L were detected at MW-26A (immediately
downgradient of the OHM facility) in 1999-2001, compared to more recent concentrations that
are close to 20 ug/L for PCE and 10 ug/L for TCE. This suggests that remediation efforts at the
OHM facility have provided improvements in water quality. However, concentrations of PCE in
ground water above 1,000 ug/L continue to be found sporadically at all three elevations where
data are collected (17-20 ft bgs, 30 ft bgs, 50 ft bgs) at the OHM facility, and sometimes very
high concentrations are detected (such as 75,000 ug/L of PCE at PCX-ID in April 2007 or 10,000
ug/L at PCX-5B in April 2008). This suggests there is sufficient source strength remaining at the
OHM facility to impact ground water with VOC concentrations above standards for many years if
it is not more fully remediated or contained, and it is possible that VOC concentrations
immediately downgradient of the OHM facility could increase above current levels in the future,
especially if source area remediation is not continued.
• A slug of higher VOC concentrations appears to be migrating to the south towards the gap in
capture between EW-03 and EW-04. At MW-31A, TCE concentrations greater than 500 ug/L
were observed in 2004 but have decreased substantially since to less than 50 ug/L (with a related
increase in cis-l,2-DCE). This declining trend pre-dates ISCO injections, and likely results from
positive impacts of the AS/SVE system and resulting reduction in source strength emanating from
the OHM facility. With that conceptual model, one would expect subsequent concentration
declines at MW-18 (further downgradient), and in fact TCE concentration at MW-18A has
declined significantly since 2006 (from 510 ug/L in April 2006 to ~10 ug/L recently). Over that
same period, TCE concentration at MW-15B (further downgradient) has been increasing from
approximately 20 ug/L in 2004 to more than 150 ug/L recently. These trends support the concept
of a slug of VOC impacts migrating to the south. Note that MW-15B is located downgradient of
EW-03, but it is not clear if it is located inside or outside the capture zone of EW-03.
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At the next downgradient sampling locations from MW-15B (i.e., MW-202 and MW-203
clusters) the TCE concentrations have noticeably increased during the last several quarterly
sampling events. These two monitoring well clusters are located in the gap in capture between
EW-03 and EW-04 discussed earlier. At MW-203B the most recent TCE concentration (January
2009) was up to 27 ug/L. It is quite possible that higher VOC concentrations exist east of the
MW-202 and MW-203 clusters. There is the potential that concentrations of VOCs may continue
to increase at the MW-202 and MW-203 clusters (and/or east of those clusters) over the next
several years, and that VOC impacts may spread further to the southeast into an area where there
are no current monitoring wells or institutional controls (which end at 16th Avenue).
As noted in site reports, vinyl chloride is detected at only two locations in the October 2008
sampling: MW-32A (0.98 ug/L) and MW-37A (5.5 ug/L). These monitoring wells are located in
the area downgradient of the Deyke and Pollard oil sites, and BTEX compounds are also detected
at these wells. It appears likely that the contamination from the Deyke and Pollard oil sites
enhances bioremediation of PCE/TCE beyond cis-l,2-DCE to vinyl chloride in this area.
VOC concentrations at many wells close to the southern municipal well field have declined
significantly overtime. Examples include MW-9A/9B, MW-13A/13B/13C/13D, and MW-8A.
This is perhaps due to effectiveness of the GET system, but may also be due to the changing flow
patterns associated with reduced pumping at the southern municipal well field over the last
decade discussed in Section 4.2.1 (i.e., the well field no longer pulls contamination that far to the
west, unlike historical pumping conditions that led to the well field being impacted).
4.3 COMPONENT PERFORMANCE
4.3.1
GROUND WATER EXTRACTION SYSTEM
Design rates and actual rates achieved in 2008 are summarized below:
EW-01R
EW-02C
EW-03
EW-04
W-l
Total
Design Rate (gpm)
200
500
150
150
400
1,400
Design Max Rate (gpm)
240
600
200
180
600
1,820
Avg Flow 2008 (gpm)
209
457
143
127
591
1,528
*from Table 1-2 of 2008 GET annual report
The site team indicated during the RSE site visit that the specific capacity of the pumping wells is not
calculated or tracked over time. No major issues have been reported with well fouling during the RSE
site visit, but the operators did mention iron build-up on one of the extraction wells.
During RSE visit it was mentioned that the pumps at the extraction wells are throttled with valves, not
VFDs.
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4.3.2
GET TREATMENT SYSTEM
The GET treatment system has relatively low influent concentrations, and meeting the effluent standards
has not been an issue. Recent influent and effluent concentrations are indicated below:
PCE
Standard: 5 ug/L
TCE
Standard: 5 ug/L
Cis-l,2-DCE
Standard: 70 ug/L
Trans- 1,2-DCE
Standard: 100 ug/L
Vinyl Chloride
Standard: 2 ug/L
Oct-07
Jan-08
Apr-08
Aug-08
Oct-08
Oct-07
Jan-08
Apr-08
Aug-08
Oct-08
Oct-07
Jan-08
Apr-08
Aug-08
Oct-08
Oct-07
Jan-08
Apr-08
Aug-08
Oct-08
Oct-07
Jan-08
Apr-08
Aug-08
Oct-08
Influent Cone (ug/L)
0.76
0.87
0.5 U
0.5 U
0.5 U
32
17
8.2
0.5 U
9.10
24
24
7.7
0.5 U
22
0.5 U
2.3
0.93
0.5 U
1.7
0.5 U
0.5 U
0.5 U
0.5 U
Effluent Cone (ug/L)
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5
0.74
0.5 U
1.2
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
0.5 U
The treatment system is clean and well-maintained. Historic problems with manganese fouling have
generally been addressed by modifying the chemical addition, acid washing the air stripper packing on a
quarterly basis (a 3-day event each quarter), and cleaning the paddle flow meters approximately three
times per year.
The City generally uses all of the treated water (approximately 735 million gallons per year) for water
supply except the water that is used during the acid wash events. The water from the acid washing events
(approximately 12,000 gallons total for all four acid wash events) is neutralized and discharged to the
City sanitary sewer system. This appears to be an efficient use of resources.
4.3.3
AS/SVE SYSTEM
The AS/SVE and the source area ISCO injections (see below) have been relatively effective at reducing
VOC mass in the source area. However, AS/SVE system operation has been intermittent over the past
few years, and continued operation of the AS/SVE in its current configuration would likely have marginal
effectiveness in remediating the source area to standards. Between August 2007 and December 2008, the
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AS system operated approximately 50% of the time, the low vacuum SVE system operated approximately
37% of the time, and the high vacuum system operated approximately 49% of the time. The following
limitations to system performance are noted:
• Approximately the first 10 ft of the subsurface is clay, and when the water table rises as high or
higher than the bottom of this clay, it becomes impractical for the SVE system to extract vapors
derived from the air sparging. As a result, the AS/SVE system is not operated during periods
with a high water table. The small diameter SVE wells may also complicate vapor extraction
during periods of high water. Approximately 50% of the recent low vacuum SVE system down
time is attributed to shutdowns during periods with a high water table.
• To prevent mounding and surfacing of potassium permanganate during source area ISCO
injections at the OHM facility, operation of the AS/SVE system is discontinued during and
immediately following ISCO events at the OHM facility. Approximately 35% of the recent down
time is attributed to ISCO injections. The ART well continued to operate during the ISCO
events.
• Air sparge points and SVE wells in the source area have been focused in the open areas on the
property, primarily the parking lot, sidewalks, and surrounding alleys. Significant source material
is likely located beneath the facility, and thus has not and cannot be addressed with the current
system configuration.
• The air sparge points and SVE wells are each configured into common distribution headers,
which makes it difficult to target specific areas that may historically receive inadequate flow.
• A number of leaks have been identified in the AS and both SVE systems, reducing air delivery
and air extraction, and possibly biasing sampled vapor concentrations with atmospheric air. The
November 2006 Revised Remedial Process Optimization Report and the 2008 AS/SVE Annual
report discuss many of the operational problems. Mass removal has reportedly decreased (as
would be expected as mass is removed); however, given the various issues described in these
documents, it is unclear if the mass removal rate has decreased due to leaks (i.e., reduced air
delivery via the sparge system and reduced air recovery and/or dilution of the SVE systems).
This system has made a significant contribution to limiting the amount of mass that migrates from the
source area. However, given that ground water concentrations are still widely present above 1,000 ug/L
(and even above 10,000 ug/L in some locations) after 8 years of system operation, it does not appear that
cleanup levels will be reached in the near term using this approach. In the B and C monitoring well
intervals, the plume appears to be detached from the source area (see figures in Attachment A),
suggesting that significant contaminant mass has not migrated from the source area in these intervals for
several years. In the A monitoring well interval, the plume is still attached to the source area but the
concentrations in wells downgradient of the source area (e.g., MW-26A) are substantially lower than they
were historically. For example, MW-26A had a PCE concentration of 41,000 ug/L in December 1999.
The concentrations at MW-26A and other shallow monitoring wells downgradient of the source area have
decreased substantially since AS/SVE system operation began. By January 2005, the PCE concentration
at MW-26A was below 100 ug/L, and the concentration has been below 40 ug/L for eight consecutive
quarters. However, given the sporadic high ground water concentrations that continue to be detected at
the OHM facility, it appears reasonable to conclude that this system, as it currently operates, will not
restore ground water to concentrations below cleanup levels. It is unclear how high concentrations in
ground water downgradient of the AS/SVE system may increase, if system operation were discontinued.
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4.3.4 ISCO INJECTIONS
During the RSE visit, it was stated that the ISCO was not expected to restore the aquifer to cleanup
criteria. Rather, the goal of the ISCO was to reduce VOC concentrations in the source area(s) and mid-
plume to an extent that operation of the GET system might be shortened.
OHM Injections
The results of the OHM ISCO injections are mixed and difficult to interpret given the intermittent
operation of the AS/SVE system between ISCO injection events. The ground water monitoring results
from the PCIX-1 and PCIX-2 wells indicate that concentrations generally decreased in the shallow zone
(PCIX C and D intervals, which are 20 feet and 30 feet deep respectively) but increased substantially in
the deep zone (PCIX B interval, which is approximately 50 feet deep). The October 2008 monitoring
results had the highest TCE concentrations in PCIX-1B and PCIX-2B since 2004 or earlier. The TCE
concentration at PCIX-1B was approximately 2,500 ug/L and the TCE concentration at PCIX-2B was
approximately 10,000 ug/L. The ART well also experienced significant increases in TCE concentrations
over the duration of the ISCO injection events. These results suggest that contamination may have been
pushed and/or mobilized into the vicinities of these sampling locations rather than remediated by either
the air sparging from PCIX-1 and PCIX-2 or the ISCO injections.
The results at the MW-44 cluster show the opposite result. The shallow TCE concentrations increased to
approximately 500 ug/L, but the deeper TCE concentrations decreased from as high as 5,000 ug/L to
under 20 ug/L.
Some locations showed notable improvement, such as SVE-3, in which concentrations decreased from
1,100 ug/L to under 50 ug/L over the course of the two 2008 injections. The MW-45 cluster (both
shallow and deep) also showed positive results. TCE concentrations in the shallow zone decreased from
4,300 ug/L to under 20 ug/L.
The mixed results appear indicative of subsurface heterogeneity and the difficulty in evenly distributing
the oxidant such that it contacts all of the contamination. The ISCO injections have been successful at
reducing contaminant mass, but based on the current data do not seem to have made meaningful progress
in restoring the source area.
Mid-Plume Injections
The mid-plume injections were originally intended to address the portion of the plume that would take the
longest to migrate to and be extracted by the GET system. The injections appear to have provided little
benefit to overall plume remediation as described below.
The first and third round of injections was conducted upgradient of the MW-23 and MW-41 clusters. A
review of the data suggests that low level TCE and PCE concentrations were generally remediated in the
vicinity of these wells by the ISCO injections; however, TCE concentrations in MW-23B were generally
unaffected and concentrations in general were already declining due to source area remediation
(AS/SVE). The cis-l,2-DCE concentrations in the vicinity of these wells did not appear to be
significantly affected by the ISCO injection. PCE appears to continue to migrate at low levels from the
source area, so recontamination of the area partially remediated by the first and third mid-plume ISCO
events is a possibility.
There are no monitoring wells immediately downgradient of the second round of mid-plume ISCO
injections. MW-18 is the closest monitoring well to this injection location and is located over 600 feet
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downgradient. There may have been a slight response in the TCE concentrations at MW-18A to the
ISCO injection, but in general, there was no apparent benefit for any constituent at the MW-18B and
MW-18C intervals. PCE concentrations remain above 200 ug/L at MW-18B as late as January 2009.
4.4 COMPONENTS OR PROCESSES THAT ACCOUNT FOR MAJORITY OF
ANNUAL COSTS
The RSE team has estimated the approximate annual O&M costs based on information provided by CDM
and the City of Columbus.
Item Description
Routine project management (HGL + CDM)
Engineering Support (HGL + CDM)
O&M Labor
Electricity
Supplies & routine maintenance
Ground water sampling (129 wells annually, ~88
wells in other three quarters, for approximately 400
samples per year)
Quarterly and annual reporting for the GET and
AS/SVE systems, ISCO injections, and all ground
water monitoring
Lab Analysis**
Total Estimated Annual Cost
Approximate Annual Cost
$ 75,000 (GET + AS/SVE + ISCO)
$ 200,000 (GET + SVE+ISCO)
$120,000 (GET)
$ 40,000 (AS/SVE)
$ 50,000 (GET)
$ 25,000* (AS/SVE)
$ 105,000 (GET)
$ 20,000 (AS/SVE)
$185,000***
$185,000***
$ 2,000 (GET)
$1,007,000
*when all components operating
**most lab analysis is performed by contract lab and is not billed to the site.
*** based on the total of sampling/reporting of approximately $370,000 per year provided to the
RSE team and using the RSE team's professional experience with costs for labor, equipment
and travel associated with sampling
In addition, the expected total ISCO injections costs (2007 to 2009), including injections still to
be performed after the RSE visit, is approximately $710,000.
Note that the system provides some avoided costs to the City of Columbus, which uses most of
the water pumped and treated at the GET system for public water supply. For instance, wellhead
maintenance and electricity costs for those wells are covered as part of the ground water remedy,
such that those costs are not borne by the City. Thus, some additional benefit to the community is
provided by this system.
4.4.1
UTILITIES
Electricity cost for the GET system is incurred by the City of Columbus and estimated to be
approximately $4,000 per month ($48,000 per year), primarily for well pumps, treatment system blower,
treatment system transfer pumps, and electric heaters in the GET building. Electricity cost for the
AS/SVE system is incurred by CDM and is estimated to be approximately $2,000 per month when the
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system is operating as intended, primarily for the compressors and blowers. Based on the Loup Power
District (electrical utility) rate schedules, the average cost per kWh is approximately $0.03 per kWh for
the GET system and approximately $0.07 per kWh for the AS/SVE system. The difference is based on
the different power consumptions of the two facilities. A number of other fees apply, including a demand
charge for the GET system. Other utilities such as water and phone are very minor relative to the overall
costs.
4.4.2 NON-UTILITY CONSUMABLES AND DISPOSAL COSTS
For the GET treatment system, the largest cost in this category is for chemicals, which appear to cost on
the order of $75,000 per year. These chemicals include the polyphosphate-type chemical added to
prevent fouling of the air stripper, as well as acid used for the acid washes of the air stripper. The
polyphosphate is added to the public water supply prior to distribution regardless of the treatment for
VOCs. Other costs in this category include equipment maintenance and supplies (approximately $30,000
per year).
For the AS/SVE system, the liquid phase GAC for the condensate from the knockout tanks is estimated to
be replaced once per year, and the vapor phase GAC was reportedly changed out approximately 2 years
ago. These changeout frequencies may be heavily influenced by system down time.
4.4.3 LABOR
There are multiple entities associated with the operation of the current remedy:
Hydrogeologic (HGL)
HGL is EPA's contractor and is responsible for the following with respect to routine O&M for the GET
and AS/SVE systems:
• Overall project management
• Weekly O&M visits to the AS/SVE system (~1.5 hrs per visit for one person)
• Participation in quarterly long term monitoring (LTM) events (shared between HGL and CDM)
• Review reports generated by CDM
For special projects, HGL directly subcontracts for drillers and other contractors (rather than CDM) to
avoid a double-markup.
It was indicated during the RSE site visit that the October monitoring event requires a four person crew
for approximately 10 days, and the other events generally require a four person crew for 8 to 9 days.
There has been a continuing evaluation of the use of PDBs at 13 wells without dedicated pumps. The
PDB data have not matched low-flow results well at the OHM wells but have matched the low-flow data
well at the 11 FMGP wells and two TS wells. The current plan is to use PDBs to sample the FMGP and
TS wells, which will save about a day worth of labor for four samplers, but revert to low-flow sampling at
OHM. No further comparisons of the PDB and low-flow datasets are planned.
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COM
CDM is a subcontractor to Hydrogeologic. CDM was the original design contractor for the GET system.
CDM provides services for routine O&M including the following:
• Project management and reporting
• Engineering and technical support to the City
• Modeling updates
• Quarterly reports for the GET system
• Quarterly reports for the AS/SVE system and ISCO injections
• Participation in quarterly monitoring events (shared between HGL and CDM)
CDM also provides engineering design services for special projects associated with the remedy (e.g.,
pipeline relocation, and management and technical support of the ISCO injections), and CDM shared
responsibility for engineering design services on the ART well design.
City of Columbus
The City of Columbus operates under a cooperative agreement with EPA and expenses associated with
the remedy are funded through an EPA grant. The City is responsible for:
• Extraction well maintenance
• Operation of the GET system treatment plant operation
The operators reportedly spend approximately 2 hrs per day seven days a week for routine operation, plus
3 days per quarter for acid wash of the GET system.
4.4.4 CHEMICAL ANALYSIS
Chemical analysis is generally provided by the Contract Laboratory Program and is not billed to the site.
If the costs were billed to the site, it is estimated that the analytical costs would be on the order of $10,000
annually for the current process monitoring program and on the order of $50,000 annually for long-term
monitoring of ground water. The effluent from the GET system is sent to the State Lab and is billed to
the project, and there is minor cost expended in field kits (e.g., Hach kits).
4.5 APPROXIMATE ENVIRONMENTAL FOOTPRINTS ASSOCIATED WITH
REMEDY
4.5.1 ENERGY, AIR EMISSIONS, AND GREENHOUSE GASES
Based on the annual electricity cost of $48,000 and the schedule of fees and rates for the Loup Power
District (electric utility), approximately 1.5 million kWh of electricity is used on an annual basis by the
GET system. This usage compares closely to electricity usage estimated from motor sizes and VFD
settings. The annual electrical usage from the AS/SVE system is more difficult to calculate due to the
intermittent and unpredictable operation of the system. Based on a survey of 2008 electricity bills, the
electrical usage for 2008 was approximately 278,000 kWh, which is significantly smaller than the usage
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that would occur if the system were operating at capacity for the whole year. If the system were operating
at full capacity for a whole year, electricity usage would likely be three to four times higher. The
electricity provided by the Loup Power District is generated from a hydroelectric facility that was
constructed in the 1930s. As a result, the incremental environmental footprint of the electricity consumed
by the GET and AS/SVE systems is minimal. Table 4-1 provides the estimated electrical usage at the site
over a 10-year period and includes an emission factor of 0 for the hydroelectric power.
Other direct energy usage associated with the site is for gasoline and diesel. Gasoline is associated with
transportation to and from the site for a variety of activities, and diesel is associated with freight of the
ISCO to the site, equipment operation for the ISCO injections, and transportation of ISCO injection
equipment to the site. Table 4-1 summarizes the gasoline and diesel usage for the site. The usages
associated with the GET and AS/SVE systems are on an annual basis. The usage for the ISCO injections
is for the life-cycle of the ISCO injection project.
Air emissions of greenhouse gases and other pollutants would result from manufacturing of the chemicals
used at the site and from other services (e.g., laboratory analysis) associated with site activities. Estimates
of emissions from these are provided in Table 4-1. Ground water monitoring, although it applies to all
remedial activities, was included under the GET system footprint.
A review of Table 4-1 shows that the footprint of 10 years of operation of the GET and AS/SVE systems
combined is approximately to the footprint for the entire ISCO project, and the ground water monitoring
program comprises approximately 60% of the GET system footprint. This comparison highlights the
environmental benefit of using renewable hydroelectric power for power-intensive remedies. Had the
electricity been provided by fossil fuels, the annual footprint for the GET system would have been almost
three times the footprint for the full ISCO project.
With respect to criteria pollutants (e.g., ozone, nitrogen oxides, sulfur dioxide, lead, particulate matter,
and VOCs), Columbus is located in Platte County, and criteria pollutant air quality monitoring data for
Platte County is not available from the EPA Air Data website. The data for nine Nebraska counties are
included, and eight of the nine counties had Air Quality Indexes below 100 indicating good or moderate
air quality. The remaining county is Douglas County, the most populous county in the State (where
Omaha is located). Based on the results from these nine counties, it is presumed that Platte County has
good to moderate air quality. It is further noted that most of the emissions associated with the remedy are
not local to the site (i.e., they are for materials manufacturing or transportation). As a result, the
emissions primarily occur at the locations of the chemical/material manufacturing or along the highways
between the consultant/contractor offices and Columbus. As such, the criteria pollutants are not expected
to have significant adverse affects on the local or regional environment. The primary emissions
associated with the site are the VOCs emitted from the air stripper off-gas. As calculated and discussed in
Section 5, the emission rate is very low compared to the requirements for a minor source of hazardous air
pollutants (HAPs). This suggests that the air stripper off-gas would not significantly affect regional air
quality. More local effects on Columbus residents have not been quantified.
4.5.2 WATER RE SOURCES
Approximately 735 million gallons per year are extracted, treated, and provided to the City as potable
water. Water for the acid washing (approximately 12,000 gallons per year) and water from the AS/SVE
knockout tanks (difficult to quantify, but relatively low in volume) are treated and disposed of to the City
sanitary sewer system. Water used for the make-up of the potassium permanganate solution for the ISCO
injections is returned to the aquifer and therefore does not represent a net removal of water from the
aquifer.
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The polyphosphate chemicals that are added to the water prior to treatment by the air stripper and
distribution to the public contribute to phosphorous loading to natural waters. It is unlikely that the
current wastewater treatment facility effectively removes phosphorous, so it is expected that the
phosphorous will enter the receiving water body. This could increase the potential for eutrophication in
this receiving water body. The RSE team did not quantify the amount of phosphorous entering the
system or the potential for eutrophication (which may be insignificant) because the chemicals are added
to the water for public distribution and this RSE is not intended to be a review of the water supply and
wastewater treatment provided by the City of Columbus.
4.5.3 LAND AND ECOSYSTEMS
The entire remedy is confined to the urban, commercial, and residential sections of the City of Columbus.
The GET system occupies space immediately surrounding other water treatment infrastructure for the
City, and the AS/SVE system was constructed in an attachment to the dry cleaning facility and is likely
unnoticeable by the community. The ISCO injections are the aspect of the remedy that likely creates the
most disturbance to the community. The injections involve running diesel equipment in commercial and
residential areas, which results in incremental noise and exhaust. However, the site team and contractors
have done a good job of planning and executing the ISCO injections to minimize inconvenience and
nuisance to the community.
4.5.4 MATERIALS USAGE AND WASTE DISPOSAL
Materials comprise one of the larger components of the remedy footprint, but waste disposal is fairly
minimal. Primary materials usage includes GAC for treating the off-gas and knockout tank water from
the AS/SVE system, potassium permanganate for the ISCO injections, and chemical additives for the
GET system. The GAC is regenerated, which requires energy but fosters materials reuse and reduces
waste disposal. The potassium permanganate is injected into the aquifer and generates relatively little
waste on-site (typically buckets and personal protective equipment used during the injection process).
Waste is likely generated during the manufacturing process and associated supply chain for the potassium
permanganate but is not quantified or accounted for here due to lack of manufacturing-specific
information. Similar to potassium permanganate, the chemical additives for the treatment plant do not
generate any on-site waste but some waste (not quantified or characterized as part of this report) is likely
generated in the manufacturing process and supply chain. However, the RSE team understands that some
of this chemical usage introduced as part of the GET system reduces that amount of chemicals required
for other water treatment provided by the City in order to provide water of suitable quality to the
community.
4.6 RECURRING PROBLEMS OR ISSUES
There have been issues with shut-downs of extraction wells due to electrical storms and power failures.
In 2008 a surge suppressor was installed on all extraction wells to protect the flow meters.
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4.7 REGULATORY COMPLIANCE
During the RSE process, the site team (including the City) did not report any exceedances of discharge
standards or other compliance related standards.
4.8 SAFETY RECORD
During the RSE process, the site team (including the City) did not report any health and safety concerns
or incidents related to the remedial activities.
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5.0 EFFECTIVENESS OF THE SYSTEM TO PROTECT HUMAN
HEALTH AND THE ENVIRONMENT
5.1 GROUND WATER
There continues to be a continuing source of ground water impacts at the OHM facility. Concentrations
of PCE in ground water above 1,000 ug/L continue to be found sporadically at all three elevations where
data are collected (17-20 ft bgs, 30 ft bgs, 50 ft bgs). Sometimes very high concentrations are detected
(such as 75,000 ug/L of PCE at PCX-ID in April 2007 or 10,000 ug/L at PCX-5B in April 2008) with
much lower values detected before and after. It is likely that the combined efforts of AS/SVE and ISCO
have provided some (and perhaps substantial) concentration reductions, but it is apparent that these efforts
have not entirely remediated this source area. The sporadic nature of the high concentration values
suggests that there may be localized changes to the shallow ground water flow system that occur due to
the AS/SVE operations and/or the ISCO injections. It is also possible that sporadic nature of the high
concentration values could be due to pulses of new contamination being released to the ground water
system due to rainfall events and/or a rising and falling water table. The concentrations of PCE and
daughter compounds immediately downgradient of the OHM facility appear to be lower than historical
ground water concentrations observed between the OHM facility and the railroad tracks. This potentially
suggests that remediation efforts to date (including AS/SVE and ISCO) have reduced the strength of the
continuing source at the OHM facility. Nevertheless, the RSE team believes there is sufficient source
strength remaining at the OHM facility to impact ground water with VOC concentrations above standards
for many years if it is not more fully remediated or contained.
An additional area of concern is an apparent gap in hydraulic capture between GET system extraction
wells EW-03 and EW-04. As discussed in Section 4.2.1, the latest site modeling report (Appendix D of
the 2008 GET System Annual Performance Report, April 2009) identified that full capture is not
occurring in the area between EW-03 and EW-04, and that migration continues between these wells to the
southeast. That modeling report further identified that pumping rate increases at EW-03 and EW-04, or
installation of an additional well, is needed to address this issue, and that current pumping rates are
maintained to prevent drawing in nonstrippable ground water contaminants associated with the Columbus
FMGP and Deyke and Pollard Oil sites. During the RSE site visit it was stated by the site team that,
although some VOC impacts appear to extend south or southeast beyond the reach of the extraction wells,
these impacts appear to not be increasing significantly (i.e., a "steady-state" condition). The RSE team
does not fully agree with this assessment. As discussed in Sections 4.2.1 and 4.2.2, a slug of higher VOC
concentrations appears to be migrating to the south towards (and through) this gap between EW-03 and
EW-04. It is quite possible that higher VOC concentrations exist east of the MW-202 and MW-203
clusters. There is the potential that concentrations of VOCs may continue to increase at the MW-202 and
MW-203 clusters (and/or east of those clusters) over the next several years, and that VOC impacts may
spread further to the southeast into an area where there are no current monitoring wells. The site team
may need to more fully address the potential ramifications of these observations.
The water supply provided by the effluent of the GET system consistently meets drinking water
standards. Furthermore, there appear to be institutional controls in place to generally prevent
consumption of impacted water. However, the RSE team notes that the eastern boundary of the
institutional controls (16th Avenue) may not be sufficient south of the railroad tracks. As discussed above,
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it is possible that the plume is migrating to the southeast in this area, and it is possible the VOC
concentrations above standards may be detected now or in the future east of 16th Avenue.
5.2 SURFACE WATER
No impacts to surface water have been observed or are anticipated.
5.3 AIR
Emissions from the AS/SVE system are treated with vapor carbon, so no significant impacts are
anticipated from that system. For the GET system, VOC influent concentrations are quite low (generally
less than 50 ug/L), resulting in only minor emissions of VOCs to the atmosphere.
1500gal 3.785L 0.05 mg 1kg 2.2Ibs 1440 min 365 day 328Ib
2—X X -X — X X X =
min gal L 10 mg kg day yr yr
By comparison, the criteria for a minor source under the NDEQ air quality operating permit program is 5
tons per year (or 10,000 pounds per year) of any one hazardous air pollutant (F£AP). PCE, TCE, and
vinyl chloride are listed as F£APs (cis-l,2-DCE is not).
With respect to vapor intrusion, during the RSE site visit the RSE team inquired if potential for vapor
intrusion has been evaluated in the immediate vicinity of the OHM facility, such as at residences
immediately to the south. It was stated that there has been some evaluation regarding the potential for
vapor intrusion throughout the plume, but it was not clear if there had been specific evaluation of vapor
intrusion immediately adjacent to the OHM facility. After the RSE site visit, information regarding
previous vapor intrusion studies was provided by the RPM, including some analysis at the OHM facility
using a PID (there were detections of VOCs) and an analysis performed on a time-integrated summa
canister sample from the basement of one residence on 22nd Street located downgradient of the OHM
facility. At the residence there was PCE detected in the air sample (1.1 ug/m3), but this concentration was
below the EPA Region 9 criteria of 3.3 ug/m3 for PCE in ambient air. The site has indicated that the
potential need for additional evaluation of the vapor intrusion pathway will be considered during the next
Five-Year Review which is due in 2010.
5.4 SOIL
At the OHM facility there is the potential for PCE product to be present above the water table below the
dry cleaner building in the clays immediately below ground surface. This represents a potentially
continuing source of ground water impacts, and it cannot be fully investigated or remediated while dry
cleaning operations continue at the site.
5.5 WETLANDS AND SEDIMENTS
These media are not affected or potentially affected by site contamination.
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6.0 RECOMMENDATIONS
Cost estimates provided herein have levels of certainty comparable to those done for CERCLA Feasibility
Studies (-30%/+50%), and these cost estimates have been prepared in a manner generally consistent with
EPA 540-R-00-002, A Guide to Developing and Documenting Cost Estimates During the Feasibility
Study, July, 2000. The costs and sustainability impacts of these recommendations are summarized in
Tables 6-1 and 6-2.
6.1 RECOMMENDATIONS TO IMPROVE EFFECTIVENESS
6.1.1 EVALUATE THE NEED FOR FURTHER EVALUATION OF POTENTIAL FOR VAPOR
INTRUSION NEAR OHM FACILITY
Although some evaluation of the potential for vapor intrusion near the OHM facility was provided to the
RSE team, it is recommended that the sufficiency of those evaluations be considered by the site team, and
that the potential need for additional evaluation of the vapor intrusion pathway in the vicinity of the OHM
facility should be evaluated by the site team. The site team has indicated that the potential need for
additional evaluation of the vapor intrusion pathway will be considered during the next Five-Year
Review, which is due in 2010. No cost has been estimated for this recommendation because it is planned
to be included within the Five-Year Review.
The affect on the environmental footprints of this recommendation are not quantified since no specific
action beyond discussions and reporting is made at this time.
6.1.2 DISCONTINUE PUMPING AT EW-04 AND SHIFT PUMPING WEST TO EW-03
As discussed in Section 4.2.1, EW-04 extracts water that is currently below standards for VOCs, and it
potentially increases the potential for water to escape capture to the east of EW-03. It makes sense to
terminate extraction at EW-04, and increase extraction at EW-03 to the extent possible (perhaps requiring
a larger pump to be installed at EW-03) if piping can accommodate more water at EW-03 than the current
pump can generate, and if there is adequate available drawdown to support the increased pumping rate.
To the extent that water currently pumped at EW-04 cannot be allocated to EW-03, some could be also
allocated to EW-01R. The RSE team notes that the site team is concerned that increased pumping at EW-
03 could cause PAHs from adjacent sites to extracted, and if necessary, a simple pre-treatment unit with
GAC to treat the PAHs could be implemented for water from this well before it is combined with water
from the other wells. This recommendation should have a relatively insignificant cost to implement,
unless a new pump is required at EW-03 or pre-treatment for EW-03 is in fact needed (there may be a
need to periodically monitor MW-3 for PAH's, but this extra cost will likely be offset by saved electricity
from not pumping EW-04).
The environmental footprint of this recommendation is relatively minor given that the pump in EW-04 is
powered by renewable hydroelectric power and that the chemicals that are added to the extracted water
are added anyway prior to distributing the water to the public.
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6.1.3 ADDRESS CALIBRATION ISSUES WITH THE FLOW MODEL
As discussed in Section 4.2.1, comparison of simulated versus observed conditions (including
observations already noted in the GET quarterly reports) suggests that the existing model does not
accurately represent the flow system under current pumping conditions. The RSE team believes this
model is an important tool for assisting with capture zone evaluation and future decisions regarding
pumping locations/rates. In particular, some of the re-calibration should include comparison of simulated
versus observed drawdown over time caused by pumping at specific extraction wells. These data can be
collected by doing short-term shutdown tests at individual extraction wells (e.g., for several days, one
extraction well at a time) and measuring changes in water level over time at nearby monitoring wells
before and during the shutdown tests with transducers (plus at a well beyond the influence of that
extraction well to serve as a control). Previous pump test data from EW-01R may also be available for
this type of analysis. Also, shut-down of EW-04 is recommended above, and changes in water level
resulting from that action could also be monitored to provide the information required. This type of
transient calibration near extraction wells, in response to changed pumping stresses, is important because
the ability of the model to accurately predict capture depends on the ability of the model to predict
drawdown due to pumping. Re-calibration should also address the overall match of water levels versus
time (as noted in Section 4.2.1, many of the hydrographs from the recent model update indicate that
simulated water levels are too low after GET extraction began, especially in the latter part of the
calibration period). The RSE team believes the fieldwork associated with several shutdown tests could be
collected for less than $15,000, and updating the existing model could be performed for less than $40,000.
The environmental footprints of this recommendation are not quantified as they are expected to be
relatively low and minor in comparison to the benefits of the recommendation with respect to remedy
protectiveness.
6.1.4 ADDRESS POTENTIAL PLUME MIGRATION TO THE SOUTHEAST (DELINEATION
AND ICs) AND ASSOCIATED POTENTIAL ACTIONS
As discussed in Sections 4.2.1 and 4.2.2, the VOC concentrations have been increasing at the MW-202
and MW-203 clusters, higher concentrations could exist to the east of those clusters, and this portion of
the plume may continue to grow in extent to the southeast beyond MW-202 and MW-203. The RSE team
notes that there are no monitoring wells to the east or southeast of MW-203 to provide for delineation
now or in the future. Furthermore, the institutional controls that are in place are bounded to the east by
16th Avenue, and it is possible that VOCs above standards have migrated (or will migrate) east of 16th
Avenue south of the railroad tracks. The RSE team recommends that the site team develop and implement
a strategy for addressing additional plume delineation and extending the boundary of the institutional
controls.
One approach for delineation would be to collect direct push samples from intervals corresponding to the
A and B zones, with sampling for VOCs, followed by installation of several permanent wells clusters.
Approximately 3 days of direct push sampling in the region south and east of MW-203 would likely be
appropriate, at an approximate cost of $40,000 (including a brief work plan, field work, analysis at the
contract lab, and a short report). If relatively low VOC concentrations are determined throughout the area
(e.g., similar to those at the MW-202 and MW-203 clusters) then subsequent addition of two clusters of
monitoring wells with two intervals (A and B zones) would likely be appropriate to monitor
concentrations over time to make sure concentrations do not get significantly worse. These four wells
might cost on the order of $50,000 to install, and an additional $10,000 per year to sample quarterly with
analysis for VOCs. If much higher VOC concentrations are found east or southeast of the MW-203
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cluster, then additional permanent wells may be needed for delineation and tracking of concentration
trends over time. The RSE team has no basis for estimating the cost of extending the institutional
controls to the east, but assumes it could be accomplished for less than $15,000.
Assuming that plume expansion to the southeast is occurring, the need to address that expansion with
remedial measures will need to be evaluated by the site team. The outcome of that evaluation may
depend on the results of the delineation activities suggested above. However, the RSE team provides the
following thoughts regarding pros and cons of various potential alternatives.
• Additional Extraction Well. It is conceivable that a new extraction well could be added, perhaps
in the vicinity of MW-203. The water could be piped to the existing pipeline north of the railroad
tracks, or in a separate pipeline south of the railroad tracks (along 10th Street). This location
would be more conducive to creating an overlapping zone of capture with EW-03 than the current
location of EW-04. If the well is placed near the MW-203 cluster, then the MW-203 cluster
would provide for water level measurements in the close proximity of the new extraction well.
This new well might draw in mobile BTEX compounds from the upgradient Deyke and Pollard
oil sites, but those compounds should be readily addressed by the air stripper in the GET system.
It is less likely that PAHs would be drawn in to this new well at substantial concentrations
because PAHs are generally less mobile than VOCs, but if necessary, a simple pre-treatment unit
with GAC to treat the PAHs could be implemented for water from this well before it is combined
with water from the other wells. This option is relatively straightforward to implement and would
eliminate the gap in capture that currently exists between EW-03 and EW-04. A disadvantage is
that new infrastructure is required. It is also possible that updated modeling could show that the
gap in capture between EW-03 and EW-04 could be addressed with higher rates at those wells. If
that is the case, pre-treatment might also be required to address the PAHs from the other nearby
sources.
• Enhanced Bioremediation. The presence of vinyl chloride downgradient of the Deyke and
Pollard oil sites suggests that it is possible to drive reductive dechlorination beyond cis-l,2-DCE
if the aquifer is driven to more reducing conditions. Injections of electron donor material (e.g.,
emulsified vegetable oil, molasses, lactate) could be implemented throughout a treatment zone
(with addition of microbes if needed) in the area south of the railroad tracks not captured by the
GET extraction system. The injection approach would be similar to the IS CO injections
previously performed. However, unlike ISCO which is consumed rapidly, the enhanced
bioremediation approach generally provides for a treatment period of up to a year or more before
needing to be fortified. An advantage of this approach is that it does not require additional
infrastructure. A disadvantage is that there is a chance the full reductive dechlorination will not
be accomplished if insufficient donor is added. The site team also noted that it is generally
difficult to adequately stimulate bioremediation for treating ground water where total VOC
concentrations are less than 100 (ig/L at the start of treatment. This is due to the inability to grow
large quantities of dechlorinating biomass at low contaminant concentrations. Therefore,
conducting enhanced bioremediation at the toe of the plume may not be feasible.
• Monitoring Only. This would only be appropriate if it can be determined that, based on modified
extraction rates at EW-04 and EW-03 recommended above, sufficient capture is then provided
and that any contamination already beyond the modified capture zone will attenuate over time
and will not negatively impact potential receptors. This would obviously be a lower cost
alternative if it could be justified from an effectiveness standpoint.
33
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The RSE team estimates that evaluating these and other potential alternatives after the plume delineation
activities are performed might require on the order of $50,000. The actual implementation costs cannot
be estimated at this time.
There is a significant difference in the environmental footprints of these three options. Assuming the
monitoring only option is considered a baseline or reference approach (because it would likely be a
component of each option), the analysis can focus on the incremental footprints associated with the
additional extraction well and the enhanced bioremediation options. The following table reflects the
incremental carbon footprint of these two options. An arbitrary but reasonable operational period of 5-
years is assumed. The assumptions used in completing the table are presented in Attachment B.
Energy
Electricity*
Diesel
Gasoline
Units
kWh
gallons
gallons
CO2 equiv.
Emission
Factor
Obs)
0
22
19
Energy Subtotal
Materials
Steel
HOPE
EVO
Other
pounds
pounds
pounds
2
2
3.5
Materials Subtotal
Total
Additional Extraction Well
Quantity
400,000
410
0
5,000
11,200
0
20% mark-up
C02e
(Ibs)
0
9,020
0
9,020
10,000
22,400
0
6,500
38,900
47,920
Enhanced Bioremediation
Quantity
0
11,400
4,400
0
0
500,000
10% mark-up
C02e
(Ibs)
0
250,800
83,600
334,400
0
0
1,750,000
175,000
1,925,000
2,259,400
EVO = emulsified vegetable oil
* Emission factor for electricity is assumed to be zero due to the use of renewable hydroelectric power
Other Environmental Footprints
The additional extraction well would require the materials as described in Attachment B (and other
materials and equipment that were not specified). In addition, some disposal or materials recycling would
be required for the asphalt and/or concrete removed during the trenching process, and the drill cuttings
and mud from drilling and developing the well. There would be a negligible effect on local water
resources given that all of the water extracted would be for beneficial purposes. There would be an effect
on the local commercial and residential neighborhoods from construction activities, but the effect on local
ecosystems would be negligible given the urban/suburban setting of the project.
The enhanced bioremediation approach would require the materials described in Attachment B (and other
materials and equipment that were not specified). In addition, some disposal would be required for
disposables used during the injection process. There would be a negligible effect on local water resources
given that all of the water extracted for make-up water would be reinjected. Water quality would
generally be improved during the 5-year period and the lingering effects of the in-situ bioremediation
should attenuate before the remaining VOCs. There would be an effect on the local commercial and
residential neighborhoods from injections activities, but the effect on local ecosystems would be
negligible given the urban/suburban setting of the project.
34
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As a general note, the carbon footprint of the additional extraction well is very small relative to the
enhanced bioremediation option because of the renewable hydroelectric power that is used to power the
pump. In the absence of quantifying other environmental footprints, the carbon footprint can be used as
an indicator, assuming that other pollutants, waste, and raw materials usage would generally scale with
the carbon footprint.
6.2 RECOMMENDATIONS TO REDUCE COSTS
6.2.1 DISCONTINUE ISCO AFTER CONTRACT is COMPLETED
As discussed in Section 4.3.4, the ISCO injections have likely reduced some VOC mass and
concentrations at the OHM facility and at the mid-plume injection locations, but the ISCO has not
provided complete remediation of VOCs in either area, and it is not clear that the ISCO injections will
provide any benefit with regard to the overall remediation timeframe. This recommendation to
discontinue the ISCO injections technically will not save any money since the site team already plans to
discontinue the ISCO injections, but rather this recommendation is intended to convey the RSE team's
concurrence with that approach.
The environmental footprint for the ISCO project is substantial relative to the footprints of the other
(arguably more effective) components of the remedy.
6.2.2 CONTINUE TO USE PDBs WITHOUT EXTENSIVE COMPARISONS
The PDB data have not matched low-flow results well at the OHM wells but have matched the low-flow
data well at the 11 FMGP wells and two treatability study (TS) wells. The current plan is to use PDBs to
sample the FMGP and TS wells, which will save about a day worth of labor for four samplers, but revert
to low-flow sampling at OHM. RSE team concurs with this approach assuming extensive comparisons
with data from low-flow sampling be curtailed to save on sampling costs and reporting effort. The site
team has indicated that no further comparisons of the PDB and low-flow datasets are planned. If PDB
results are to be used for important remediation decisions or comparison to cleanup standards, then those
specific results could be confirmed with samples obtained by low-flow sampling. No specific cost
savings are quantified herein since this is a continuation of the current practice, but some savings will
clearly be achieved by curtailing the comparisons between samples from PDBs versus low-flow sampling.
This recommendation has a negligible effect on the environmental footprint of the remedy.
6.2.3 REDUCTIONS IN MONITORING/REPORTING
This is a complex site where flow conditions have changed and multiple remedial approaches have been
implemented. Nevertheless, the total estimated cost of $375,000 per year for sampling and reporting for
the combined GET and AS/SVE system is an extremely large number, and an attempt to reduce the
sampling and reporting cost is merited.
The RSE team makes the following suggestions:
• Currently there are two separate quarterly reports (GET system, AS/SVE plus ISCO), plus two
separate annual reports (GET system, AS/SVE plus ISCO). This results in 10 report submittals
35
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per year. It is recommended that this be reduced to one annual comprehensive report per year for
all current or future components of the remedy (i.e., a reduction from ten submittals per year to
one submittal per year). This will significantly reduce duplication in reporting. In addition, all
data will be reported in the same place. Currently, for instance, ground water quality data for
wells at the OHM facility are reported in the AS/SVE reports and water quality for the other site
wells are reported in the GET reports. Providing all the data in a unified report would be
preferable.
The site team has done a commendable job of sampling wells in "clean" areas annually rather
than quarterly. The RSE team suggests changing some of the wells currently sampled quarterly
to either semi-annually or annually.
o For the 25 wells currently sampled quarterly at the OHM facility, it is suggested that
sampling associated with long-term monitoring be performed annually. This will result
in 75 fewer samples taken per year. If an aggressive remediation approach is
implemented at the OHM facility (see Section 6.4.1) then this annual LTM sampling
schedule might be augmented by additional process monitoring samples for a limited
time while the aggressive remedy is conducted, but that should be considered as part of a
OO J ' r
specific remedy option and not a component of LTM.
o For the remainder of the site, it is suggested that quarterly sampling be reserved for the
portion of the plume from the MW-26 cluster to the southeast towards the MW-203
cluster. This area is of greatest concern with respect to changing concentration over time
given the current flow directions (which are more to the southeast than was the case when
the plume developed), the continuing potential source at the OHM facility, and the
potential expansion of the plume to the southeast discussed earlier. It is suggested that the
28 wells (listed below) be sampled semi-annually rather than quarterly. This will result in
56 fewer samples taken per year.
MW-1A
MW-6A
MW-17A
MW-3B
MW-9B
MW-2A
MW-8A
MW-206A
MW-4B
MW-11B
MW-3A
MW-11A
KV-5
MW-5B
MW-13B
MW-4A
MW-13A
MW-1B
MW-6B
MW-14B
MW-5A
MW-14A
MW-2B
MW-8B
MW-17B
MW-206B KV-4 MW-13C
It is suggested that comprehensive water levels be collected semi-annually rather than quarterly,
with both water level maps presented in the annual report.
It is suggested that plume maps for the comprehensive sampling round (October) be presented in
the annual report. If there are significant deviations from those data in samples collected in other
quarterly or semi-annual events, those can be explained in the text of the annual report.
For sampling rounds other than the comprehensive sampling round, it is suggested that sampling
results be processed and reviewed by the consultant when they are received (e.g., update
concentration trend plots), and if any of the results are unexpected and significant with respect to
a potential short-term decision, then that could be reported in a short memo to the EPA RPM.
Similar treatment could be given to an issue with a component of the remedy that requires timely
attention.
36
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The RSE team believes that implementing the monitoring and reporting recommendations above should
provide significant cost savings. Reducing the number of samples taken by approximately 131 per year
as described above (plus some related QA/QC sampling), and reducing the water level events from
quarterly to semi-annual, might save on the order of $60,000 per year on sampling labor plus equipment
and travel. We estimate that an annual reporting budget of $100,000 per year should be sufficient for
generating a comprehensive annual report plus any interim data processing as the year progresses,
resulting in savings on reporting on the order of $85,000 per year. Thus, the RSE team estimates that the
annual costs for sampling and reporting could be reduced by approximately $145,000 per year if these
recommendations are implemented. The RSE team notes that the City of Columbus has expressed some
concern about reducing the sampling frequency to less than quarterly.
Based on the emission factors presented in Table 4-1, reducing the analysis by 131 samples per year (plus
some related QA/QC sampling) might reduce the carbon footprint by approximately 13,000 pounds of
carbon dioxide per year. The amount of materials usage and disposal by the laboratory associated with
this site would also be reduced. The reduction in the sampling effort should also reduce the carbon
footprint but not by a significant amount given that the majority of the footprint (as calculated) is based
on travel to and from the site from the consultant/contractor offices, and roughly the same amount of
travel would still need to occur.
6.2.4 PROJECT MANAGEMENT AND TECHNICAL SUPPORT MOVING FORWARD
As presented in Section 4.4, the following annual costs were estimated based on information provided to
the RSE team:
• Project Management - $ 75,000 per year (GET + AS/SVE + ISCO)
• Engineering Support - $200,000 per year (GET + AS/SVE + ISCO)
These represent combined cost estimates for HGL and CDM. The manner in which the costs were
provided to the RSE team makes it difficult to determine how much of the costs pertain to each
component of the remedy (GET, AS/SVE, ISCO). However, on a move-forward basis, the ISCO support
should end after 2009, and it is possible that operation of the AS/SVE system will also be terminated
based on recommendations in this RSE report. Since the GET system is expected to operate for an
extended period of time, the RSE team recommends that project management and engineering support
costs for the GET system be clearly documented and managed independently from other investigation or
remediation activities. For the GET system alone these costs are expected to be substantially lower than
the amounts provided above, and based on experience of the RSE team reviewing other Fund-lead sites, a
budget of $50,000 per year for project management and $50,000 per year for engineering support should
be adequate for the GET system. With respect to other potential investigations, remedial actions, or
special projects (such as a GeoProbe investigation, extending institutional controls, evaluating options for
the OHM facility, etc.) the cost for associated project management and/or engineering support should be
treated as independent "one-time" or "annual" tasks that are completely separate items from annual O&M
of the GET system. In this manner, the long term costs of the GET system can be tracked and managed.
Therefore, the RSE team believes move-forward project management and engineering support costs for
the GET system alone should be approximately $175,000 per year less than the costs estimated in Section
4.4 for the combined GET plus AS/SVE plus ISCO remedies. The cost impacts from other items beyond
the GET system will depend on what items are performed, and if those are "one-time" or "annual" cost
items.
37
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6.3 RECOMMENDATIONS FOR TECHNICAL IMPROVEMENT
6.3.1 MEASURE AND TRACK SPECIFIC CAPACITY OF WELLS
During the RSE site visit it was stated that the specific capacity of the extraction wells is not measured or
tracked. The specific capacity of each extraction well is calculated as the pumping rate divided by the
drawdown at that extraction well (i.e., gpm per ft of drawdown). The value of tracking this parameter is
that a decline in specific capacity indicates well fouling and can serve as an indicator for performing well
rehabilitation. The measurement of drawdown (i.e., versus a non-pumping condition) at an individual
well can be complicated by several factors, such as regional water level changes and interference from the
other extraction wells. However, corrections can be made for background water levels based on changes
in water level far away from the extraction wells, and the interference between wells is a relatively minor
impact especially if extraction rates remain relatively consistent over time. Therefore, adding this to the
routine monitoring at the site will only involve measuring depth to water at each extraction well when
other site water levels are measured, and then performing a few simple calculations. This is not expected
to have any impact on annual costs.
6.3.2 CONSIDER VFDs FOR EXTRACTION WELL PUMPS
The extraction well pumps (totaling 90 HP) contribute significantly to the overall electricity usage of the
GET system, and the pumps are throttled to reduce flow. The flow could be more efficiently controlled
with VFDs, and this would reduce electricity usage and electrical costs. At the time the GET system was
designed it was determined that the cost for installing variable frequency drives (VFDs) was not justified.
It was determined at that time to regulate the flow rate with a manual valve at the well head. The
electricity used by the facility is renewable hydroelectric power, reducing electrical usage with VFDs
would not significantly reduce the environmental footprint of the remedy. Similarly, because the
electrical rates are so low (approximately $0.03 per kWh), the cost savings would not be as significant as
they would be at many other locations in the country. If hydroelectric power capacity in the region is
recognized as being relatively limited, the site team might consider installing VFDs to help conserve that
capacity. The RSE team estimates that installing VFDs might reduce electrical usage on the order of
150,000 kWh to 200,000 kWh per year. Purchasing and installing the five VFDs might cost
approximately $25,000, and savings of approximately $5,000 per year might result. The site team has
indicated that use of VFDs for the extraction wells will be considered by EPA and the City of Columbus
if automated flow adjustment is desired.
6.4 CONSIDERATIONS FOR GAINING SITE CLOSE OUT
6.4.1 CONSIDER ALTERNATE ACTIONS AT OHM FACILITY
As discussed earlier in this report, the RSE team believes that the combined efforts of AS/SVE and ISCO
at the OHM facility have provided some (and perhaps substantial) concentration reductions, but it is
apparent that these efforts have not entirely remediated this source area. Furthermore, there are areas
beneath the existing dry-cleaning building that cannot be fully investigated or addressed by the current
remedial approaches. Remaining subsurface impacts at the OHM facility could be a source of dissolved
ground water impacts downgradient of the OHM facility for many years.
38
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The RSE team recommends that a "remedy alternatives" report for the OHM facility be prepared, for an
estimated cost of approximately $50,000 (no field work is assumed for preparing this report). The
following potential options should be evaluated (all except the second bullet below assume that operation
of the AS/SVE system would be discontinued):
• Separate P&T System at the OHM Facility - This would presumably consist of one new
extraction well, treatment via a tray-stripper, and discharge to ground water a short distance
downgradient of the extraction well (in several injection wells or a trench located just beyond the
expected capture zone of the extraction well). An advantage of this approach is that it would
provide reliable hydraulic containment of the source area if properly designed and implemented,
eliminating the potential for new ground water impacts to occur downgradient of the OHM
facility. This option would not require any further investigation of the OHM facility, and would
not require the cleaning business to be relocated. Also, the City could likely operate this system
very cost-effectively as an addition to the existing operation of the GET system. A disadvantage
is that this would be a long-term cost item that would likely operate indefinitely, and that new
infrastructure would be required. This option would likely require a modification to the ROD.
• Augment extraction locations for AS/SVE. This would presumably consist of continued operation
of the AS/SVE system with additional locations added for air injection and withdrawal. The
advantage is that some additional mass removal might occur, and the use of existing
infrastructure would be maximized. However, this option would be subject to the same
limitations of the existing AS/SVE system, which include difficulties due to subsurface
heterogeneities, high water tables, and inaccessible areas under the building (unless the existing
dry cleaning business is relocated). The likelihood of eliminating the source area with this
approach is relatively low.
• Enhanced Bioremediation - This would presumably involve injections of electron donor material
(e.g., emulsified vegetable oil, molasses, lactate) throughout a treatment zone (with addition of
microbes if needed) at the OHM facility. The injection approach would be similar to the ISCO
injections previously performed. However, unlike ISCO which is consumed rapidly, the
enhanced bioremediation approach generally provides for a treatment period of up to a year or
more before needing to be fortified. An advantage of this approach is that it does not require
additional infrastructure. A disadvantage is that there is a chance the full reductive dechlorination
will not be accomplished if insufficient donor is added. As with AS/SVE and ISCO, the existing
business provides a limitation to accessible areas unless that business is relocated. This option
would likely require a modification to the ROD.
• Thermal Treatment - This could include use of resistive heating or steam. An advantage of this
approach is that subsurface heterogeneities might not be as much of a limitation compared to
ISCO, bioremediation, or AS/SVE. Precautions would need to be implemented to address
potential impacts to neighboring businesses and residences. The high water table would cause
potential issues with collection of vapors (some form of ground water pumping might be required
to lower the water table, which may not be practical given the high hydraulic conductivity of the
shallow aquifer and the need to subsequently treat/discharge that water). This option would
require relocation of the existing dry cleaning business, and would likely be rather expensive to
implement. This option would likely require a modification to the ROD.
• Excavation - This would presumably include excavation to the water table which includes mostly
clay. This would require relocation of the existing dry cleaning business. During the RSE site
visit it was stated that this option was previously considered, but the AS/SVE was selected
because the contractor convinced the site team that AS/SVE could quickly eliminate the source
39
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area. This option would include significant cost and disruption. Another disadvantage is that it
would not address any residual DNAPL that might be present below the water table.
• More ISCO - This has not proven to be fully effective at eliminating the VOCs in the treatment
areas, so this alternative would likely not be favored from an effectiveness standpoint.
• No-Action - Given the potential for continued impacts to ground water downgradient of this
source area, this is likely an unacceptable option with respect to protectiveness.
The environmental footprints for the above options are not specifically estimated. Rather the remedial
options are classified into two different categories: "relatively low environmental footprint" and
"relatively high environmental footprint".
The P&T, continued AS/SVE, and thermal remediation options all are considered to have relatively low
environmental footprints, primarily because the primary resource that will go into the remedies is
hydroelectric power, which has a very small environmental footprint (given that the hydroelectric facility
has already been constructed). All of the remedies would involve construction, but it is likely that the
construction activities will be fairly similar. The P&T system would likely include the installation of a
new extraction well, installation of an air stripper or additional GAC units, piping, and controls.
Continued AS/SVE would need to include additional sparge and extraction points to be effective, but the
remainder of the system could likely remain the same. The thermal remedy would likely include the most
significant construction activities, but because of the short-term nature of the project much of the
materials and equipment would be reused at other facilities. Although the thermal remedy would likely
require extended closing or relocation of the facility, the environmental footprint of this would likely be
comparable to the P&T system or AS/SVE system continuing to occupy the treatment building on the
property for many years.
The ISCO, bioremediation, and excavation options are considered to have relatively high environmental
footprints. The ISCO and bioremediation options are in this category because they depend on the
manufacturing of a significant amount of material in other parts of the country. The manufacturing
facilities likely do not use a high proportion of renewable energy, and the materials must be transported to
the site and injected. The injection activities alone would likely have a similar footprint to the "relatively
low footprint" options mentioned above, and the materials (e.g., potassium permanganate or EVO) would
all be additional to the footprint. The excavation option would involve fairly extensive construction
activities and would also likely involve transport and disposal of material, which occupies landfill space.
It would also require relocation of the facility and demolition of the existing building.
In summary, the evaluation of these options in the "remedy alternatives" report should include the
reliability of containing or remediating the source area, the up-front and life-cycle costs, the impacts to
the community (visual, noise, odor, etc.), and the need to relocate the existing business (which has a
financial cost and would require substantial administrative effort). A small P&T system may ultimately
be preferred, even though it does not eliminate the subsurface impacts immediately beneath the OHM
facility and it might operate for an indefinite period.
6.5 RECOMMENDATIONS FOR IMPROVED SUSTAINABILITY
No specific recommendations are provided in this category, but sustainability has been considered during
the development of the above specific recommendations. One general recommendation is to note the very
high environmental footprint associated with the ISCO injections relative to the P&T and AS/SVE
40
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activities at this site, and to recognize the "environmental value" of implementing remedies that utilize the
renewable energy provided locally through hydroelectric power rather than implementing remedies that
depend on chemical manufacturing in other parts of the country. The electricity used by this remedy is
provided from a hydroelectric facility with a very limited environmental footprint (given that the
hydroelectric facility has already been constructed).
41
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Table 4.1 Energy and Atmosphere Footprint Analysis
P&T Svstem (over 10 years)
Energy
Electricity
Diesel
Gasoline
Energy subtotal
Materials
Polyphosphate dispersant
Hydrochloric acid
Materials subtotal
Other Services
Process monitoring analysis
Groundwater monitoring analysis
Disposal of acid wash residuals
Other services subtotal
Quantity
15,000,000
0
2,000
NA
16,000
$100,000
$50,000
NA
Unit
kWh
gallons
gallons
NA
gallons
dollars
dollars
NA
CO2 equiv
emission
factor
(Ibs/unit)
0
0
19
NA
3.2
1
1
NA
P&T Subtotal (Ibs over 10 years)
total (Ibs)
0
0
38,000
38,000
0
51,200
51,200
100,000
50,000
0
150,000
239,200
%of
Total
0%
0%
4%
4%
0%
5%
5%
10%
5%
0%
14%
23%
ISCO Applications
Energy
Diesel
Gasoline
Energy subtotal
Materials
Potassium Permanganate
Materials subtotal
Values for ISCO are for Life of ISCO Project
3,600
1,500
$450,000
gallons
gallons
dollars
22
19
1
ISCO Subtotal (for life of ISCO project)
79,200
28,500
107,700
450,000
450,000
557,700
8%
3%
10%
43%
43%
54%
AS/SVE (over 10 vears)
Energy
Electricity
Gasoline
Energy subtotal
Materials
GAC
Materials subtotal
Waste Disposal
Diposal of water from knockout tanks
Disposal subtotal
2,780,000
5,500
70,000
NA
kWh
gallons
pounds
NA
0
19
2
NA
AS/SVE Subtotal (Ibs over 10 years)
0
104,500
104,500
140,000
140,000
0
0
244,500
0%
10%
10%
13%
13%
0%
0%
23%
Remedy Total Over Nominal 10-yr Period (Ibs)
1,041,400
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Usage and Emission Factor Notes for Table 4-1.
Except where otherwise noted, information regarding emission factors was obtained from EPA Climate
Leads Program, the National Renewable Energy Laboratory life-cycle inventory at www.nrel.gov/lci, or
the EUROPA Reference Life-Cycle Database. Costs used in deriving emission factors are consistent with
costs during Spring 2009. The emission factors developed here are rough approximations based on
simplifying assumptions. They are intended to provide only approximate environmental footprints to
help understand the affects potential changes to the remedy may have on the footprint of the remedy.
Electricity
Quantity
• GET System -1.5 million kWh based on electricity bills, motor sizes, and VFD settings
• AS/SVE System - 278,000 kWh based on 2008 electricity bills, recognizing that the system
operated intermittently
Emission Factor - A negligible emission factor is assumed given that the power is generated from a
hydroelectric facility and that typical activities for maintaining that hydroelectric facility and the
transmission lines are fundamental aspects of operation and are not incremental as part of the GET and
AS/SVE system operation.
Diesel
Quantity - Diesel usage results from operating the ISCO injection equipment, transportation of the ISCO
injection equipment to the site, and delivery of the potassium permanganate. Estimates are derived as
follows:
• Approximately 135 days of injections are assumed based on an average rate of four ISCO
locations per day (which is consistent with the pace at the site) and a total of 539 injection
locations by the time the ISCO work is completed in 2009. The ISCO operator reported that
approximately 12 gallons of diesel is used per day of injection. Therefore, diesel usage for the
injections is approximately 1,620 gallons.
• The ISCO equipment is housed in Indianapolis, which is approximately 700 miles from the site.
The round trip will have been made approximately 8 times by the conclusion of the ISCO
contract, and fuel usage of 10 miles per gallon is a reasonable approximation to fuel usage for the
rig used for the injections. The diesel usage for transportation is therefore approximately 1,120
gallons.
• A diesel usage rate of 0.023 gallons per ton mile and a transport distance of 500 miles are
assumed for estimating the diesel used for transporting potassium permanganate to the site. Over
the course of the contract (through 2009) the total mass of potassium permanganate injected will
have been approximately 150,000 pounds (75 tons). This translates to approximately 860 gallons
of diesel.
Emission Factor - 22 pounds of carbon dioxide per gallon of diesel (Climate Leaders.
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Gasoline
Quantity - Gasoline is used for transportation to and from the site and to power the ISCO injection pump.
The ISCO injection pump requires approximately 10 gallons per week or 270 gallons over the course of
the project. Gasoline usage for transportation is estimated as follows:
• For two support vehicles for the ISCO contractor (assuming 700 miles each way, 8 round trips
over the course of the project, and 15 miles per gallon), gasoline usage is approximately 1,500
gallons over the course of the project.
• For routine AS/SVE maintenance, one trip per week for 52 weeks per year, at a distance of 160
miles roundtrip, and an average fuel economy of 15 miles per gallon, estimated gasoline usage is
approximately 550 gallons per year.
• For CDM's participation in the quarterly sampling, one trip per quarter for four quarters per year,
at a distance of 600 miles roundtrip, and an average fuel economy of 15 miles per gallon,
estimated gasoline usage is approximately 160 gallons per year.
• For HGL's participation in the quarterly sampling, one trip per quarter for four quarters per year,
at a distance of 160 miles roundtrip, and an average fuel economy of 15 miles per gallon,
estimated gasoline usage is approximately 40 gallons per year.
Emission Factor - 19 pounds of carbon dioxide per gallon of gasoline (Climate Leaders).
Granular Activated Carbon
Quantity - 7,000 pounds per year based on the change out of one 2000-pound liquid phase GAC unit per
year and two 5,000-pound vapor phase GAC unit every two years.
Emission Factor - 2 pounds of carbon dioxide per pound of GAC, see Attachment B.
Potassium Permanganate
Quantity - Based on the reported usages, approximately 150,000 pounds (75 tons) of potassium
permanganate has been used throughout the injection program.
Emission Factor - 1 pound of carbon dioxide per dollar of chemicals, based 10% of the cost of the
materials resulting from the direct use of fossil fuels or electricity derived from fossil-fuels, and
approximately 10 pounds of carbon dioxide emitted per $1 of fossil fuels consumed. 10 pounds would
represent a blend of natural gas, diesel, gasoline, and coal. The cost of the permanganate is assumed to be
approximately $3 per pound for a total cost of $450,000 for the life of the ISCO project.
Other Treatment Chemicals
Quantity - Approximately $75,000 per year is spent on a variety of chemicals for the treatment plant;
however, the majority of these chemicals (including the dispersant for iron and manganese) are already
added for supplying water to the public. Only the hydrochloric acid and disinfectant for acid washing and
disinfecting the air stripper are "additional" for the purposes of evaluating environmental footprints. Acid
washing is conducted once a quarter and uses approximately 400 gallons of 30% hydrochloric acid for a
total usage of approximately 1,600 gallons of 30% hydrochloric acid per year. Relatively minor amounts
-------
of sodium hydroxide and sodium hypochlorite are used to neutralize the acid washing waste and to
disinfect the air stripper. The specific gravity of 30% hydrochloric acid is 1.14. Given the density of
water is approximately 8.34 pounds per gallon, one gallon of 30% hydrochloric acid solution includes
approximately 2.85 pounds of hydrochloric acid. This translates to a usage of approximately 4,600
pounds of hydrochloric acid per year.
Emission Factor - Hydrochloric acid can be produced by combining the hydrogen and chlorine gas
generated as intermediates in the production of sodium hypochlorite and dissolving the resultant hydrogen
chloride gas in water. With the hydrogen and chlorine combined, the sodium hydroxide would remain
unused and available for distribution. Assuming the footprint for sodium hypochlorite production is
evenly distributed among the intermediate products of sodium hydroxide, hydrogen, and chlorine gas, the
footprint for each intermediate would be the same (approximately 1.1 pounds of carbon dioxide per pound
of hydrochloric acid). This translates to a total of approximately 5,100 pounds of carbon dioxide for the
1,600 gallons of 30% hydrochloric acid or 3.2 pounds of carbon dioxide per gallon of 30% hydrochloric
acid.
Other Services
Quantity - For disposal of the acid wash residual to the POTW, the carbon and other air emission
footprints is assumed to be non-additional (NA) because the volumes discharged are extremely small
compared to the capacity of the POTW. No operational changes are made as a result of this discharge and
no operational changes would be made if the discharge was discontinued. For laboratory services, a
breakdown of materials and energy are not directly quantified. The emission factor used is based on a
percentage of service cost directed toward energy from fossil fuels. Approximately $60,000 in laboratory
analysis is assumed and likely includes fuel for transport, electricity for operating the laboratory and
equipment, chemicals and disposables associated with sample preparation and analysis, and disposal.
Emission Factor - 1 pounds of carbon dioxide per dollar spent on the service, based on 10% of the cost
resulting from direct use of fossil fuels and approximately 10 pounds of carbon dioxide per $1 of fossil
fuels consumed. 10 pounds of carbon dioxide would represent a blend of natural gas, diesel, gasoline,
and coal.
References
Climate Leader GHG Inventory EPA-430-K-08-004, May 2008
National Renewable Energy Laboratory (NREL), Life-Cycle Inventory Database (www.nrel.gov/lci)
maintained by Alliance for Sustainable Energy, LLC.
-------
Table 6-1. Cost Summary Table
Recommendation
6.1.1 Evaluate the Need
for Further Evaluation of
Potential for Vapor Intrusion
Near OHM Facility
6.1.2 Discontinue
Pumping at EW-04 and Shift
Pumping West to EW-03
6.1.3 Address
Calibration Issues with the
Flow Model
6.1.4 Address Potential
Plume Migration to the
Southeast (Delineation and
ICs) and Associated
Potential Actions
6.2.1 Discontinue ISCO
After Contract is Completed
6.2.2 Continue to Use
PDBs Without Extensive
Comparisons
6.2.3 Reductions In
Monitoring/Reporting
6.2.4 Project
Management and Technical
Support Moving Forward
6.3.1 Measure and Track
Specific Capacity of Wells
6.3.2 Consider VFDs for
Extraction Well Pumps
6.4.1 Consider Alternate
Actions at OHM Facility
Reason
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Cost-
Effectiveness
Cost-
Effectiveness
Cost-
Effectiveness
Cost-
Effectiveness
Technical
Improvement
Technical
Improvement
Site Closeout
Additional
Capital Costs
($)
$0
Negligible
$55,000
$155,000
$0
(already
planned)
Not
quantified
$0
$0
$0
$25,000
$50,000
Estimated
Change in
Annual Costs
($/yr)
$0
Negligible
$0
$10,000
$0
(already
planned)
Not
quantified
($145,000)
($175,000)***
$0
($5,000)
$0
Estimated
Change in Life-
Cycle Costs
$*
$0
Negligible
$55,000
$355,000
$0
(already
planned)
Not
quantified
($2,900,000)
($3,000,000)***
$0
($100,000)
$50,000
Estimated
Change in Life-
Cycle Costs
(net present
value)
$**
$0
Negligible
$55,000
$304,000
$0
(already
planned)
Not quantified
($2,160,000)
($2,608,000)***
$0
($50,000)
$50,000
Costs in parentheses imply cost reductions
* assumes 20 years of operation with a discount rate of 0% (i.e., no discounting)
** assumes 20 years of operation with a discount rate of 3% and no discounting in the first year
*** does not include "one-time" or "annual costs" associated with project management or engineering
support for items other than GET system operation, which should be tracked separately and not as
part of routine annual O&M
-------
Table 6-2. Sustainability Summary Table for Recommendations
Recommendation
6.1.1 Evaluate the Need for
Further Evaluation of Potential
for Vapor Intrusion Near OHM
Facility
6.1.2 Discontinue Pumping at
EW-04 and Shift Pumping West
to EW-03
6.1.3 Address Calibration
Issues with the Flow Model
6.1.4 Address Potential
Plume Migration to the
Southeast (Delineation and ICs)
and Associated Potential Actions
6.2. 1 Discontinue ISCO After
Contract is Completed
6.2.2 Continue to Use PDBs
Without Extensive Comparisons
6.2.3 Reductions In
Monitoring/Reporting
6.2.4 Project Management
and Technical Support Moving
Forward
6.3.1 Measure and Track
Specific Capacity of Wells
6.3.2 Consider VFDs for
Extraction Well Pumps
6.4.1 Consider Alternate
Actions at OHM Facility
Reason
Effectiveness
Effectiveness
Effectiveness
Effectiveness
Cost-Effectiveness
Cost-Effectiveness
Cost-Effectiveness
Cost-Effectiveness
Technical
Improvement
Technical
Improvement
Site Closeout
Effects on Sustainability
Minor
Minor
Minor
Minor
Minor (already planned)
Minor
Minor
Minor
Minor
Minor
Varies depending on option selected
-------
ATTACHMENT A
-------
2008 GET System Annual Performance Summary Report - 10th Street OU2 Site, Columbus, Nebraska
: n" '.. ..'.' .=== Operable Unit 2 Limits j^-
n
O3ZLT
-.-• Q
Municipal
Well Field
0.25
0.5
0.75
SCALE IN MILES
Filename: Y:\...\GETS-PSR\...Fig1-1.dwg
Task Order Number: 3370-002
Revised: 4/7/09 MMG
Source: USGS 7.5 minute Topographic Map
Columbus, NE, 1958, photorevised 1976.
V HGL
COM
Legend
KEY TO COUNTIES
Platte County
Figure 1.1
Site Location Map
U.S. EPA Region 7
-------
2008 GET System Annual Performance Summary Report - 10th Street OU2 Site, Columbus, Nebraska
HH
CHEZ:
HHHHBH
Filename: Y:\CAD\Tenth\GETS-PSR\SiteMap_Fig1-2.dwg
Task Order Number: 3370-002
Revised: 4/7/09 MMG
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— HydroGeoLogic, Inc
® Municipal Well Location
© Monitoring Well Nests
9 Extraction Well Location
Operable Unit 1 Limits
^^~ Operable Unit 2 Limits
^M Source Area
Legend
Figure 1.2
Site Map
U.S. EPA Region 7
-------
C:\CAD\10th Street\0uarterly Sampling\2008-10\AseriesGW.dwg 01-23-09 10:19
10th Street OU2 Site, Columbus, Nebraska
en n en
HHHHBH
SCALE IN FEET
Filename: Y:\...\QuarterlySampling\2008-10\AseriesGW.dwg
Task Order Number: 3370-002
Revised: 1/23/09 KBR
Y HGL
™ HydroGeoLogic. Inc
•- I
® Municipal Well Location
© Monitoring Well Nests
• Extraction Well Location
<8> FMGP Monitoring Well Location
-
-------
C:\CAD\10th Street\0uarterly Sampling\2008-10\BseriesGW.dwg 01-07-09 16:42
10th Street OU2 Site, Columbus, Nebraska
na
i - - | _
HHHHBH
SCALE IN FEET
Filename: Y:\...\QuarterlySampling\2008-10\BseriesGW.dwg
Task Order Number: 3370-002
Revised: 1/23/09 KBR
Y HGL
™ HydroGeoLogic. Inc
•- I
® Municipal Well Location Legend
© Monitoring Well Nests
• Extraction Well Location
® FMGP Monitoring Well Location
W$ML Potential Source Areas
1428.62 Groundwater Level at B-Level Wells (feet amsl)*
NA Not Applicable
NM Not Measured
Figure 2
"B" Level WeUs
Potentiometric Surface
Shallow Aquifer
October 2008
U.S. EPA Region 7
-------
C:\CAD\10th Street\Quarterly Sampling\2008-10\CseriesGW.dwg 01-07-09 16:32
10th Street OU2, Columbus, Nebraska
SCALE IN FEET
Filename: Y:\-..\QuarterlySampling\2008-10\CseriesGW.dwg
Task Order Number: 3370-002
Revised: 1/07/09 MMG
v HGL
^^ 11 yd ro Geologic, Inc
•• •
® Municipal Well Location
© Monitoring Well Nests
• Extraction Well Location
® FMGP Monitoring Well Location
-$- Piezometer
HHi Potential Source Areas
1428.62 Groundwater Level at C-Level Wells (feet amsl)
NM Not Measured
NA Not Applicable
Legend
Figure 3
"C" Level Wells
Potentiometric Surface
Middle Aquifer
October 2008
U.S. EPA Region 7
-------
i/ ] q ")*%, /cl h
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_i—I —A-U 1U. . .—_l—i L-..I - .
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Monitoring Well Nest -1999
RA Monitoring Well Location
Monitoring Well Nest - 1990
RI/FS Monitoring Well Location
10th Street Site
Columbus, Nebraska
TDD: S07-9906-014
PAN: 1278TSSFXX
Prepared by B. Barron
May 2000
Figure 2-7: Water Level Elevation Contour Map - A-Series Monitoring Wells (December 1999)
J4S M401
-------
C:\CAD\10th Street\Quarterly Sampling\2008-10\AseriesCombo.dwg 01-07-09 10:35 10th Street OU2 Site, Columbus, Nebraska
Detailed Source Area Plume Map
and Oxidant Injection Locations
Shown in Quarterly AS/SVE Repo
MW-27
i i\
Filename: Y:\...\2008-10\AseriesCombo.dwg
Task Order Number: 3370-002
Revised: 1/07/09 MMG
"A" Level Wells
Combined Contaminant Plume
Shallow Aquifer
October 2008
cis-1,2-DCE>70ug/L
v HGL
U.S. EPA Region 7
-------
C:\CAD\10th Street\Quarterly Sampling\2008-10\BseriesCombo.dwg 01-07-09 12:23 10tfl Street OU2 Site, ColumbUS, Nebraska
SCALE IN FEET
Filename: Y:\...\2008-10\BseriesCombo.dwg
Task Order Number: 3370-002
Revised: 1/07/09 MMG
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*»
Municipal Well Location
Monitoring Well Nests
Extraction Well Location
FMGP Monitoring Well Location
Potential Source Areas
Legend
c^
TCE > 5 ug/L
PCE > 5 ug/L
cis-1,2-DCE>70ug/L
Figure 11
"B" Level Wells
Combined Contaminant Plume
Shallow Aquifer
October 2008
U.S. EPA Region 7
-------
C:\CAD\10th Street\Quarterly Sampling\2008-10\CseriesCombo.dwg 01-07-09 13:30 10th Street OU2 Site, Columbus, Nebraska
Filename: Y:\...\2008-10\CseriesCombo.dwg
Task Order Number: 3370-002
Revised: 1/07/09 MMG
Municipal Well Location
Monitoring Well Nests
Extraction Well Location
FMGP Monitoring Well Location
Potential Source Areas
Figure 14
"C" Level Wells
Combined Contaminant Plume
Middle Aquifer
October 2008
v HGL
U.S. EPA Region 7
-------
FEED TOTE
(BIODISPERSANT)
BIODISPERSANT
METERING PUMP
Q
ai
QH
ll
II
§§
DISCHARGE
TO ATMOSPHERE
DISCHARGE TO
SANITARY SEWER
SMP-1
SUMP PUMP
FLOW
EQUALIZATION
TANK
BAG FILTER
BF-1
AIR STRIPPER
FEED PUMP
ACID CLEANING SOLUTION/
DISINFECTION
RECIRCULATION PUMP
ACID CLEANING/
DISINFECTION
RECIRCULATION LINE
BLOWER AIR INLET
- GRAVITY DISCHARGE TO STORM SEWER
-DISINFECTANT/ACID CLEANING SOLUTION
AS-1
PACKED COLUMN
AIR STRIPPER
pH TURBIDITY
AITYAr
DISCHARGE TO
MUNICIPAL WATER
TREATMENT PLANT
RECIRCULATION LINE
FLUORIDE
ADDITION
CHLORINE
ADDITION
SEQUESTRANT
ADDITION
DISCHARGE TO
CITY OF COLUMBUS
POTABLE WATER
DISTRIBUTION SYSTEM
EMERGENCY
SHOWER/EYEWASH
STATION
MUNICIPAL WATER
' TREATMENT PLANT
POTABLE
WATER
MUNICIPAL
WELLW-1
Y
PLUME INTERCEPTION
EXTRACTION WELLS
2008 GET System Annual Performance Summary Report
10th Street OU2 Site, Columbus, Nebraska
Figure 1.5
GET System Process Flow Diagram
AF-l
AIT-1
AIT-2
AS-1
B-l
BF-1
CFT-1
CMP-1
ESS-1
EW-01R
EW-02C
EW-03
EW-04
H-l
P-l
P-2
P-3
SMP-1
T-l
W-l
U.S. EPA
Region 7
Legend
BLOWER AIR FILTER INLET
pH ANALYSIS
TURBIDITY ANALYSIS
AIR STRIPPER
AIR STRIPPER BLOWER
BAG FILTER
CHEMICAL FEED TOTE
CHEMCIAL METERING PUMP
EMERGENCY SHOWER/EYEWASH STATION
UNCONFINED AQUIFER EXTRACTION WELL
CONFINED AQUIFER EXTRACTION WELL
UNCONFINED AQUIFER EXTRACTION WELL
UNCONFINED AQUIFER EXTRACTION WELL
DUCT HEATER
TRANSFER PUMP
EFFLUENT DISCHARGE PUMP
DISINFECTION RECIRCULATION PUMP
TREATMENT BUILDING SUMP PUMP
FLOW EQUALIZATION TANK
MUNICPAL WELL W-l
Filename: Y:\CAD\Tenth\GETS-PSR-2008\ProcessFlowDia_Fig1-5.dwg
Task Order Number: 3370-002
Revised: 4/7/09 MMG
HGL
~ HydroGeoLogic, Inc
-------
FROM SVE
WELLS
LIQUID
LINE
LVB1
LVB2
LOW-VACUUM SYSTEM
LTP1
FROM CVE WELLS
AND ART SYSTEM
LIQUID
LINE
AIR
AIR
HVB
HIGH- VACUUM SYSTEM
AIR
I
Fl F2 F3
AIR SPARGE SYSTEM
LINE
SUMP
TO
ATMOSPHERE
TO
CITY OF COLUMBUS
SANITARY SEWER
SYSTEM
TO
ATMOSPHERE
TO AIR
SPARGING WELLS
AND ART SYSTEM
2008 AS/SVE System Performance Summary Report
10th Street OU2 Site, Columbus, Nebraska
Figure 1.3
AS/SVE Process Flow Diagram
AD
ART
COMP
CVE
F
FM
HVB
HX
KO
LPGAC
LTP
LVB
OWS
SUMP
SVE
VPGAC
U.S. EPA
Region 7
Legend
AIR DRYER
ACCELERATED REMEDIATION TECHNOLOGIES
INTEGRATED REMEDIATION SYSTEM
AIR COMPRESSOR
CLAY VAPOR EXTRACTION
OIL FILTER
FLOW METER
HIGH VACUUM BLOWER
HEAT EXCHANGER
KNOCKOUT TANK
LIQUID PHASE GRANULAR ACTIVATED
CARBON TANK
LIQUID TRANSFER PUMP
LOW VACUUM BLOWER
OIL WATER SEPARATOR
SUBMERSIBLE PUMP
SAND VAPOR EXTRACTION
VAPOR PHASE GRANULAR ACTIVATED
CARBON TANK
Filename: Y:\CAD\Tenth\ASSVE-PSR\ProcessFlowDia_Fig1-3.dwg
Task Order Number: 3370-002
Revised: 3/27/09 MMG
v HGL
™ HydroGeoLogic, Inc
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-------
I
3
S
£
STORM SEWER INLET
-PCIX-1
-~^Y
AS-1
CVE-1
iSVE-1
E_2 I CV-E-4 jgj
AcVE-3 icVE-
AS-23
.SVE-2
SVE-3-
MW-47
-I I
PCIX-2 CC—' CVE-12 CVE-13
SCIX-2 m
Fast
Food
Restaurant
SVE-4
*^
CVE-27
^^
CVE-26
-STREET LIGHT
m
PCIX-3 PCIX-4
PCIX-5
»a i
AVMP-05
CVE-22 ^VE-23
04\AS-20 SVE;-6/ AS-19
VMP-03^
Treatment
Building
. CVE-31 T^-30 T
CVE-
AS-10
®CIX-3
CVE-24
nAAS-22
MW-44
—^«CVE-25
AS-18
^AAS-16
I*:
C fE-43
CVE+40
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-SVE-8
-15
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12
JAS-13 ^-91AS-
AS-11
SVE-7
CVE-36 CVE-37 CVE-38
i MW-26A
2008 AS/SVE System Performance Summary Report
10th Street OU2 Site, Columbus, Nebraska
Figure 1.4
OHM Source Area Site Layout
U.S. EPA
Region 7
Legend
ffi
»
Monitoring well (MW)
Sand Vapor Extraction (SVE) well (-20' Deep)
CE Pilot Combined Injection and Extraction (PCIX) well
+ Accelerated Remediation Technologies (ART) Integrated
Remediation System well
• Clay Vapor Extraction (CVE) well (~G Deep)
A Air Sparge (AS) well (-70' Deep)
HVE Horizontal Vapor Extraction well
Combined Injection and Extraction well
CIX
A VMP— 01
Vapor Monitoring Point (VMP)
Note:
1 . At each location 2 soil vapor monitoring points were
installed. One vapor monitoring point is screened at 6 feet
bgs and the other at 12 feet bgs.
Filename: Y:\CAD\Tenth\ASSVE-PSR-2008-SystemLayout_Fig1-4.dwg
Task Order Number: 3370-002
Revised: 3/27/09 MMG
y HGL
~ HydroGeoLogic, Inc
••I
-------
FEED TOTE
(BIODISPERSANT)
BIODISPERSANT
METERING PUMP
Q
ai
QH
ll
II
§§
DISCHARGE
TO ATMOSPHERE
DISCHARGE TO
SANITARY SEWER
SMP-1
SUMP PUMP
FLOW
EQUALIZATION
TANK
BAG FILTER
BF-1
AIR STRIPPER
FEED PUMP
ACID CLEANING SOLUTION/
DISINFECTION
RECIRCULATION PUMP
ACID CLEANING/
DISINFECTION
RECIRCULATION LINE
BLOWER AIR INLET
- GRAVITY DISCHARGE TO STORM SEWER
-DISINFECTANT/ACID CLEANING SOLUTION
AS-1
PACKED COLUMN
AIR STRIPPER
pH TURBIDITY
AITYAr
DISCHARGE TO
MUNICIPAL WATER
TREATMENT PLANT
RECIRCULATION LINE
FLUORIDE
ADDITION
CHLORINE
ADDITION
SEQUESTRANT
ADDITION
DISCHARGE TO
CITY OF COLUMBUS
POTABLE WATER
DISTRIBUTION SYSTEM
EMERGENCY
SHOWER/EYEWASH
STATION
MUNICIPAL WATER
' TREATMENT PLANT
POTABLE
WATER
MUNICIPAL
WELLW-1
Y
PLUME INTERCEPTION
EXTRACTION WELLS
2008 GET System Annual Performance Summary Report
10th Street OU2 Site, Columbus, Nebraska
Figure 1.5
GET System Process Flow Diagram
AF-l
AIT-1
AIT-2
AS-1
B-l
BF-1
CFT-1
CMP-1
ESS-1
EW-01R
EW-02C
EW-03
EW-04
H-l
P-l
P-2
P-3
SMP-1
T-l
W-l
U.S. EPA
Region 7
Legend
BLOWER AIR FILTER INLET
pH ANALYSIS
TURBIDITY ANALYSIS
AIR STRIPPER
AIR STRIPPER BLOWER
BAG FILTER
CHEMICAL FEED TOTE
CHEMCIAL METERING PUMP
EMERGENCY SHOWER/EYEWASH STATION
UNCONFINED AQUIFER EXTRACTION WELL
CONFINED AQUIFER EXTRACTION WELL
UNCONFINED AQUIFER EXTRACTION WELL
UNCONFINED AQUIFER EXTRACTION WELL
DUCT HEATER
TRANSFER PUMP
EFFLUENT DISCHARGE PUMP
DISINFECTION RECIRCULATION PUMP
TREATMENT BUILDING SUMP PUMP
FLOW EQUALIZATION TANK
MUNICPAL WELL W-l
Filename: Y:\CAD\Tenth\GETS-PSR-2008\ProcessFlowDia_Fig1-5.dwg
Task Order Number: 3370-002
Revised: 4/7/09 MMG
HGL
~ HydroGeoLogic, Inc
-------
2008 Groundwater Model Update Memorandum - 10th Street OU2 Site, Columbus, Nebraska
Southern Municipal
Well Field
Note:
Plumes shown are from October 2008
Filename: Y:\CAD\Tenth\AseriesCombo_Summer_Fig1.dwg
Task Order Number: 3370-002
Revised: 4/20/09 MMG
v HGL
— HydroGeoLogic, Inc
Legend
® Municipal Well Location
0 Monitoring Well Nests
0 Extraction Well Location
(8) FMGP Monitoring Well Location
^^^ Source Area
f^~ ) Particle Tracks
TCE > 5 ug/L
CD
PCE > 5 ug/L
cis-l,2-DCE>70ug/L
Figure 1
Capture Zone 'A' Level
Remediation Pumping (Summer)
U.S. EPA Region 7
-------
Modeled and Observed Water Level Data Well # 2 MW-01B
1433
1432
1431
1430
c
.2 1429
re
0)
LU
SJ
0)
ts
1428
1427
1426
1425
1424
1
observed
-modeled
1/1/2004
1/1/2005
1/1/2006
1/1/2007
Date
1/1/2008
1/1/2009
1/1/2010
-------
ATTACHMENT B
-------
Assumptions for Estimating the Energy Usage and Greenhouse Gas Emissions for the Additional
Extraction Well Option
Project Assumptions:
• New 10-inch extraction well installed approximately 2,000 feet from the treatment plant
• Extraction well has similar design to that of EW-4 (including a 10-inch steel casing)
• Extraction well replaces capacity pumped from EW-4
• Activities include burying 6-inch HDPE SDR 11 pipe in to a depth of 4 feet in a 2-foot wide,
2,000-foot long trench
• Burying 2-inch HDPE conduit and electrical cable
• Local oversight can be provided to minimize travel.
Footprint Assumptions:
• A trenching production rate (including inefficiencies) of approximately 20 cubic yards per hour
for trenching and similar time frames for backfilling and compacting, approximately 90 hours of
equipment operation (three machines each operating for 30 hours) would be required to dig, bed,
backfill and compact the trench. Assuming an average equipment horsepower of 100 HP,
average operation at rated 70% load, and a brake specific fuel consumption at this load of 0.05
gallons per HP-hr, the diesel fuel usage would be approximately 315 gallons.
• Drilling a 125-foot deep 10-inch well would likely take two days and require approximately 24
gallons of diesel.
• Additional diesel usage (not quantified) would be required for asphalt cutting and surface repair.
• Native material is suitable for bedding and backfill
• 6-inch SDR 11 HDPE is approximately 5 pounds per foot. For 2,000 feet, the total weight is
10,000 pounds.
• Equivalent 2-inch SDR 11 HDPE (for conduit) is approximately 0.6 pounds per foot. For 2,000
feet, the total weight is 1,200 pounds.
• For the well casing, 10-inch steel casing is approximately 40 pounds per foot. For 125 feet, the
total weight is 5,000 pounds.
• Equivalent carbon dioxide emission factor for HDPE is approximately 2 pounds of carbon
dioxide per pound of HDPE (based on values derived from www.nrel.gov/lci for electricity,
natural gas, diesel, and other fuels in developing the raw materials and then manufacturing the
HDPE at the plant)
• Equivalent carbon dioxide emission factor of for steel is approximately 2 pounds of carbon
dioxide per pound of steel (based on values derived from www.nrel.gov/lci for electricity, natural
gas, diesel, and other fuels in developing the raw materials and then manufacturing the HDPE at
the plant)
• An additional 20% "mark-up" on the diesel and materials accounts for the other activities and
materials not specifically mentioned, including asphalt, copper wire, well vault, pump,
instrumentation, etc.
-------
• Operating the well would likely require approximately 80,000 kWh of electricity per year, but
would have a minimal carbon footprint given that the electricity is provided from hydroelectric
power.
Assumptions for Estimating the Energy Usage and Greenhouse Gas Emissions for the Enhanced
Bioremediation Option
Project Assumptions:
• Use direct-push injections of emulsified vegetable oil (EVO) to establish a biobarrier that is 1,000
feet wide, 60 feet deep, and 30 feet long.
• Maintain the biobarrier for a period of 5 years to address the highest concentrations
• Approximately 300 injection locations (per year) would be required to evenly distribute the EVO,
and parameters for ISCO injection process (for injections, transportation, and material delivery)
apply to the bioremediation injections
• EVO requirements is based on a soil adsorptive capacity of 0.0005 pounds of EVO per pound of
soil
• Soil is approximately 110 pounds per cubic foot
• Calculated EVO requirement is approximately 100,000 pounds per year for 5 years (500,000
pounds total)
• The carbon dioxide and methane produced from the degradation of the EVO is either negligible
or non-additional in that it will remain in the subsurface for a long period of time and is derived
from organic matter that would have decayed anyway.
• Bioaugmentation of microbes would be required for the first injection event only
Footprint Assumptions:
• The emission factor for EVO product is not readily available, but the LCA Food database
www.lcafood.dk suggests approximately 3.5 pounds of carbon dioxide equivalents per pound of
product.
• Approximately 75 rig-days would be required for injections per year resulting in approximately
900 gallons of diesel per year for the injections.
• Approximately 600 gallons of diesel and 800 gallons of gasoline would be required for
transportation (i.e., usages for ISCO injections scaled by 75 days for bioremediation divided by
135 days for ISCO)
• Approximately 575 gallons of diesel per year would be required for delivering 50 tons of product
from a distance of 500 miles per year (i.e., usages for ISCO injections scaled by 75 days for
bioremediation divided by 135 days for ISCO)
• A 10% correction factor applies to account for microbe injections and additional monitoring that
might be conducted for this approach that is not conducted for competing approaches.
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Attachment B References
Climate Leader GHG Inventory EPA-430-K-08-004, May 2008
National Renewable Energy Laboratory (NREL), Life-Cycle Inventory Database (www.nrel.gov/lci)
maintained by Alliance for Sustainable Energy, LLC.
(EUROPA) European Reference Life Cycle Database (ELCD core database), version II compiled under
contract on behalf of the European Commission - DG Joint Research Centre - Institute for Environment
and Sustainability with technical and scientific support by JRC-IES from early 2008 to early 2009.
(http ://lca.j re .ec .europa.eu/lcainfohub/datasetArea.vm)
Footprint for vegetable oil obtained from Nielsen PH, Nielsen AM, Weidema BP, Dalgaard R and
Halberg N (2003). LCA food data base, www.lcafood.dk
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Derivation of Estimated Carbon Footprint for GAC
Information from Literature
Use of Adsorbents for the Removal of Pollutants from Wastewaters, by Gordon
McKay, published by CRC Press, 1995, ISBN 0849369207
Table 8.1
Granular Carbon Regeneration Process Energy Requirements
(15,000 kg/day Regeneration Rate)
System
Electric infrared furnace
Multiple-hearth furnace
Rotary Kiln
Fluid bed furnace
Fuel, kJ/kg
0
18,600
23,300
11,700
Electricity, kWh/kg
0.36
0.10
0.07
0.11
Steam, kg/kg
0
1.0
1.0
0.8
1.2
0.5
0.7
0.27
14
1.34
Ib CO2e/lb
Ib CO2e
Ib CO2e
Specific gravity of coal (www.engineeringtoolbox.com)
Specific gravity of GAC (Westates/Siemens)
Fraction of coal that is carbon
(http://www.eia.doe.gov/cneaf/coal/quarterly/co2 article/co2.html)
Carbon footprint of extracting and delivering 1 Ib of coal to a plant
(EUROPAELCD- Hard Coal)
Carbon footprint of natural gas, including natural gas production (per
therm) (NREL)
Carbon footprint of electricity (per kWh) (EGRID, US Average)
Assumptions:
Use fuel and electricity requirements for multiple hearth furnace to estimate energy required
for regeneration
Assume energy requirements for regeneration is the same as they are for initial
activation
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Calculations for Virgin Coal:
Carbon Footprint
2.4
1.68
1
0.68
2.5
0.65
8,920
1.2
0.045
0.061
4.5
Ib CO2e
Ib CO2e
Btus
Ib CO2e
kWh
Ib CO2e
Ib CO2e
Pounds of coal required to produce one pound of GAC
Pounds of that coal that is carbon
Pounds of carbon in one pound of GAC
Pounds of carbon from coal emitted to atmosphere
Pounds of carbon dioxide emitted for burning off coal (measured
pounds of CO2)
as
Pounds of CO2e emitted during coal extraction
Fuel required to activate one pound of GAC (2.2 pounds per kg and
1.055 kJ/btu)
Pounds of CO2e emitted for combustion of natural gas during
activation (100,000 btus per therm)
Electricity required to activate one pound of GAC (2.2 pounds per
kg)
Pounds of CO2e emitted for electricity generation
Total CO2e emitted for carbon activation
Energy Footprint
2.4
1440
8,920
0.045
470
10,800
Btus
Btus
kWh
Btus
Btus
Pounds of coal required to produce one pound of GAC
Energy required during coal extraction
Fuel required to activate one pound of GAC (2.2 pounds per kg and
1.055 kJ/btu)
Electricity required to activate one pound of GAC
Energy required to generate that electricity (3,413 btus/kWh and 33%
thermal efficiency)
Total energy required for virgin carbon activation
Calculations for Regenerated Coal
Footprint per Regeneration Cycle (including 10% virgin GAC to make-up for loss)
Energy
8,920 H
h 10% x 10,800 =
10,000
CO2e
1. 2 + 0.061 + 10% x 4.5 = 1.7
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Footprints over 10 Regeneration Cycles
Cycle
1
2
3
4
5
6
7
8
9
10
Energy
10,800
10,400
10,300
10,200
10,200
10,100
10,100
10,100
10,100
10,100
CO2e
4.5
3.1
2.6
2.4
2.2
2.1
2.1
2
2
1.9
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