I
DNAPL Remediation: Selected Projects
Where Regulatory Closure Goals Have
Been Achieved
I
STATUS UPDATE
Section
1.0 PURPOSE 1
2.0 OVERVIEW 2
3.0 CHALLENGES OF DNAPL
CHARACTERIZATION AND REMEDIATION 8
4.0 OVERVIEW OF DNAPL REMEDIATION
TECHNOLOGIES 9
5.0 DNAPL REMEDIATION PROJECTS 13
6.0 SUMMARY OF FINDINGS 13
REFERENCES 16
NOTICE AND DISCLAIMER 19
Appendix A: DNAPL Remediation
Project Profiles 20
Appendix B: Suspected DNAPL Threshholds
Based on Solubility Relative to One Percent
of Aqueous Solubility 49
Appendix C: Acronyms and Abbreviations 51
1.0 PURPOSE
The purpose of this paper is to highlight
sites where dense nonaqueous phase liquid
(DNAPL) source reduction has been demon-
strated as an aid in meeting regulatory
cleanup goals.1 The presence of DNAPL in
the subsurface can serve as a long-term
source of dissolved contaminant plumes in
groundwater, making it more difficult to
reach regulatory closure. However, once the
1 A few of the projects documented in this report
are still undergoing verification groundwater-
monitoring to confirm no rebound.
DNAPL source is addressed, residual
groundwater plumes may be more amenable
to treatment, including less aggressive tech-
niques such as monitored natural attenuation
(MNA) or bioremediation (U.S. Environ-
mental Protection Agency [EPA] 1999b).
This paper updates the document, DNAPL
Remediation: Selected Projects Approach-
ing Regulatory Closure, prepared in 2004
(EPA 2004a) by providing more recent in-
formation on technologies and on five addi-
tional selected sites at which DNAPL source
reduction technologies were applied.
The sites were identified by reviewing pro-
ject summaries found on various state and
federal Web sites and selecting those that
met the criteria for inclusion. The sources
also included published and nonpublished
reports, commercial websites, and inter-
views with regulatory staff. The review was
not statistically based, and the sites are pre-
sented for illustrative purposes only.
Ten of the 13 sites summarized in Table 1
and fully profiled in Appendix A have
reached regulatory closure (i.e., a no further
action [NFA] determination has been made).
NFA is defined in this document as (1) no
further active intervention will be required,
(2) there is currently no active remedial ac-
tivity taking place, and (3) the site is suffi-
ciently clean that long term monitoring is
not required or will not be required after
some specified time. At two sites (the confi-
dential chemical manufacturing plant in
Portland, Indiana, and the Avery Dennison
site in Waukgan, Illinois) the remediation
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5203 P)
EPA 542/R-09/008
August 2009
www.CLUIN.org
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was aimed at soil and they have met cleanup
goals and institutional controls are in place
to prevent use of groundwater. The King's
Bay site is in a MNA mode with MCLs be-
ing met at the property line. Since the site is
naturally anaerobic, it is anticipated that
monitoring will end soon. Most of the sites
were addressed under state cleanup pro-
grams, but four were addressed under Super-
fund (31%), and one was addressed as a
state led RCRA corrective action (8%).
The sites profiled illustrate that addressing
DNAPL source areas can lead to regulatory
closure and, as is the case in six sites, unre-
stricted use. As discussed in Section 3.0, the
benefits of DNAPL source reduction, and
especially partial source removal, are still
being debated. Although this paper does not
attempt to resolve this issue, it does provide
information that illustrates instances where
source reduction has contributed to a site
meeting cleanup goals (groundwater maxi-
mum contaminant limits [MCLs] were
achieved at five sites). This paper helps, in
part, to satisfy the recommendation of
EPA's Ground Water Task Force to better
assess and document results achieved by
DNAPL source reduction. The information
provided is also part of a national effort to
better understand current technology capa-
bilities and to illustrate the use of different
cleanup criteria.
This paper is targeted toward project man-
agers, federal and state regulatory staff, site
owners, consultants, and technology provid-
ers with a basic understanding of site reme-
diation approaches and terminology. Refer-
ences and available Web links are cited for
those seeking further information about spe-
cific remedial technologies in the Reference
section (page 16).
2.0 OVERVIEW
The presence of DNAPLs in soil and
groundwater presents unique challenges to
site remediation. DNAPLs have a specific
gravity greater than water, a relatively low
solubility, and a tendency to diffuse into
fine-grained materials in an aquifer. These
properties make DNAPL masses and residu-
als difficult to locate and characterize in the
subsurface, and they can prolong the process
of conventional remedial technologies, such
as groundwater pump-and-treat (P&T).
Due to their specific gravity, DNAPLs tend
to sink in the subsurface. Their migration
pathways tend to be complex and hard to
predict due to the heterogeneous nature of
the underlying soil and fractured bedrock.
As a result, a complicated DNAPL architec-
ture (shape and size) can develop that is
made up of pools, ganglia, and globules in
multiple soil layers and bedrock fracture
zones. And because of their low solubility,
tendency to displace water from larger soil
pores, and tendency to diffuse into silt and
clay, DNAPLs can release dissolved con-
stituents for long periods of time forming
large groundwater plumes. Constituents in
the migrating plume can diffuse into aquifer
materials under certain conditions only to
back diffuse out at a later time.
DNAPLs often are present at electronics
manufacturers, metal plating facilities, dry-
cleaners, solvent recyclers, and other sites
that have used chlorinated solvents. They
also are found at wood treatment facilities
that used creosote and at former manufac-
tured gas plants (MGPs) that produced coal
tar wastes. Chlorinated solvents, such as
tetrachloroethene (PCE) and trichloroethene
(TCE), are the most common types of or-
ganic soil and groundwater contaminants at
Superfund and other hazardous waste sites.
Site owners will likely spend billions of dol-
lars over the next several decades cleaning
up DNAPL-impacted sites (EPA 2000).
The following sections present some of the
challenges to characterizing and remediating
sites with DNAPL contamination and sum-
marize the many technologies that have been
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used to treat the DNAPL source zone. The
13 examples of sites that have successfully
addressed the source zone to meet regulatory
requirements are also summarized, including
information about the extent of contamina-
tion, the cleanup goals, and the treatment
approach. These sites are further detailed in
the profiles contained in Appendix A. For
quick reference to these sites, see Table 1.
For more information: The DNAPL focus
area on EPA's CLU-IN website further ex-
plains their chemistry and behavior as well
as characterization and remediation ap-
proaches:
http: //www .cluin. org/contaminantfocus/defa
ult.focus/sec/Dense_Nonaqueous_Phase_Li
quids (DNAPLsVcat/Overview/
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Table 1. Summary of Selected DNAPL Remediation Projects
(A List of Acronyms is Found at the End of the Table)
Site Name, Location
Technology, Period
of Operation
Media, Quan-
tity Treated
Project Goals, Program
(mg/kg= soil or sediment
u,g/L= groundwater)
Contaminant Concentrations
(Before Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
Contaminant Concentra-
tions (After Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
Project Status,
Comments
IN SITU THERMAL TREATMENT PROJECTS
Confidential Chemi-
cal Manufacturing
Facility, Portland, IN
Avery Dennison Site,
Waukegan, IL
Camelot Cleaners,
West Fargo, ND
(Superfund Removal
Program)
Former MGP Gas-
holder, North Adams,
MA
Former Wood Treat-
ment Area, Alham-
bra, CA
In situ conductive
heating (145
heater/vacuum
wells) 7/97 to 12/97
ERH (95 electrodes/
34 recovery wells)
12/99 to 11/00
ERH (56 multi-zone
electrode vents,
array of horizontal
vapor extraction
wells, and dual vac-
uum extraction
wells) 2/05 to 1/06
In situ conductive
heating (25 thermal
wells on 12-ft cen-
ters) 8/03 to 6/05
ISTD (131 heater-
vacuum wells and
654 heater-only
wells 6/03 to 9/05
(actual heating)
Soil, one area
7,500 ft2 by 18
ft deep and a
second area
600 ft2
by 1 1 ft deep
Saturated and
unsaturated
soil, 16,000yd3
Cleanup foot-
print was
10,300 ft2 and
up to 56 ft
deep, GW oc-
curs 3-5 ft bgs
and tends to be
perched
About 2,000
yd3 of soil,
debris, and coal
tar. Depth of 18
ft bgs.
Soil -16,500
yd3
(Average depth
20 ft bgs;
maximum
PCE - 8 mg/kg, TCE - 25
mg/kg, U-DCE-0.08
mg/kg (IDEM Tier II,
Industrial Land Use),
State Voluntary Cleanup
Program
MC - 24 mg/kg (IEPA
TACO), State Voluntary
Cleanup Program
Reduce VOC levels to
less than 3 mg/kg in soil
and 1 mg/L in GW, EPA
Superfund Removal Pro-
gram
Cleanup goals were to
reduce B(a)P levels to 300
mg/kg, naphthalene to
10,000 mg/kg and TPH to
10,000 mg/kg, MADEP
Total PAHs - 0.065
mg/kg (B(a)P-eq), PCP -
2.5 mg/kg, dioxins -
0.001 mg/kg expressed as
2,3,7,8-TCDD TEQ
PCE - 3,500 mg/kg, TCE - 79
mg/kg, 1,1-DCE - 0.65 mg/kg,
Suspected DNAPL
MC - 50,000 mg/kg (maximum
in soil), MC - 1,900 mg/kg (av-
erage in soil), Suspected
DNAPL
Maximum PCE concentrations
detected in soil 2,200 mg/kg and
in water 89 mg/L, Suspected
DNAPL
Maximum detected B(a)P 650
mg/kg, naphthalene 14,000
mg/kg, and TPH 230,000 mg/kg,
Observed DNAPL
Maximum concentrations: Total
PAHs - 35,000 mg/kg, PCP - 58
mg/kg, dioxins - 0.184 mg/kg as
2,3,7,-TCDD, Suspected
DNAPL
PCE -0.53 mg/kg, TCE -
0.02 mg/kg (average in soil)
1,1-DCE -not available
MC - 2.51 mg/kg (average in
soil)
One small area above 3
mg/kg; the rest were below.
All GW samples total VOCs
under 1 mg/L
16,000 gallons of coal tar
recovered; final concentration
averages were B(a)P 0.33
mg/kg, naphthalene 5.7
mg/kg, and TPH 43. 15 mg/kg
All contaminant concentra-
tions were below project
goals.
IDEM NFA letter
(Date not provided)
IEPA NFR letter
(4/01) required
institutional con-
trols
Unconditional no
further action, ex-
traction and moni-
toring wells were
removed
Site owner filed for
an Activity and Use
Limitation to the
MADEP due to
other unrelated site
problems
Certificate of com-
pletion issued
2/08/07
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Site Name, Location
Southern California
Edison Company
Visalia Pole Yard,
Visalia, CA
(Super-fund NPL)
Technology, Period
of Operation
ISTD(11 injection
and 8 extraction
wells) 5/97 to 6/00
Media, Quan-
tity Treated
depth greater
than 100 ft bgs
Soil and
groundwater
(Maximum
depth 145 ft
bgs)
Project Goals, Program
(mg/kg= soil or sediment
u,g/L= groundwater)
California Expedited Re-
medial Action Program
Pentachlorophenol 17
mg/kg and 1 ug/L ;
Benzo(a)pyrene 0.39
mg/kg and 0.2 ug/L ; and
TCDD equivalent 0.001
mg/kg and 30 pg/L
Superfund NPL with state
lead
Contaminant Concentrations
(Before Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
DNAPL (Creosote) and LNAPL
(diesel with pentachlorophenol)
pools present
Contaminant Concentra-
tions (After Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
All contaminant concentra-
tions were below project
goals.
Project Status,
Comments
Final Remediation
Action Completion
Report approved by
state 12/4/08
1C in place com-
mercial and/or in-
dustrial redevelop-
ment only
Ex Situ Thermal
Southern Maryland
Wood Treating Hol-
lywood, MD
(SuperfundNPL)
Excavation and ex
situ thermal desorp-
tion, P&T
Soil, sediment
270,000 tons of
soil
Surface soil: Total PAHs
-0.1 mg/kg B(a)P-eq
Subsurface soil: Total
PAHs -1.0 mg/kg B(a)P-
eq
Sediment: PCP - 0.4
mg/kg PCP, low molecu-
lar wt. PAHs - 3.2 mg/kg,
high molecular wt. PAHs
- 9.6 mg/kg
EPA Superfund NPL
Maximum concentration of
PAHs in surface soil and sedi-
ment 4,120 mg/kg and 41 ug/kg,
respectively, Observed DNAPL
All cleanup goals were met.
Ready for Reuse
determination is-
sued by EPA on
11/18/04. Unre-
stricted use of site
ISCO PROJECTS
Former Southern
California Edison
MGP Site, Long
Beach, CA
Former Cowboy
Cleaners Site,
Broomfield, CO
In situ ozonation
and excavation 1998
to 2001
Potassium perman-
ganate 9/01 to 8/02
Soil and GW,
340 ft by 230 ft
Soil and GW,
65,340 ft2 (1.5
acre) plume
B(a)P-eq- 1.75 mg/kg
(Site-specific risk-based
cleanup level), California
DTSC
Project goals not identi-
fied; State Voluntary
Cleanup Program
Total PAH - 2,484 mg/kg >100
mg/kg B(a)P-eq (maximum in
soil), Suspected DNAPL
PCE - 1,900 ug/L (maximum in
GW), Suspected DNAPL
B(a)P-eq - 1 .4 mg/kg (aver-
age in soil), PAH concentra-
tions in GW reduced to ND
PCE - 48 ug/L (source area)
California DTSC
will issue a Certifi-
cate of Completion
once deed restric-
tions are recorded
NFA letter issued
by State of Colo-
rado (2/03) requires
commercial use
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Site Name, Location
Dry Clean USA
#11502, Orlando, FL
Naval Submarine
Base Kings Bay, Site
1 1 , Camden County,
GA
Former Sta-Lube Site
Rancho Dominguez,
CA
Technology, Period
of Operation
SVE: 4/99 to 12/00,
P&T: 4/99 to 1/01
and 2/01 to 11/02,
Hydrogen peroxide:
10/05
P&T: 1993 to 1999
Fenton's reagent:
6/99 to 11/01
Biostimulation,
MNA: ongoing
P&T: 1997-2003
SVE: 2000-2001
Excavation: 2003
Catalyzed hydrogen
peroxide and so-
dium persulfate:
06/05 to 06/08
Media, Quan-
tity Treated
Full-scale
deepest con-
tamination was
68 ft bgs,
plume was 800
ft long and 300
ft wide
GW plume
estimated to be
700 ft by 200 ft
and 30 to 40 ft
deep
Soil and GW,
GW plume
estimated at
200 ft by 80 ft
Project Goals, Program
(mg/kg= soil or sediment
u,g/L= groundwater)
Meet contaminant target
cleanup goals: 3 ug/L
PCE, 30 ug/kg PCE, 30
Hg/kg TCE, 400 ng/kg
cis-DCE, 700 ug/kg trans
DCE, and 7 ug/kg vinyl
chloride, State Drycleaner
Program
Georgia DNR MCLs,
RCRA Corrective Action
50 ug/L MC, California
RWQCB Los Angeles
Region
Contaminant Concentrations
(Before Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
PCE - 27,300 ug/L in GW and
3.9 mg/kg detected in soil, Sus-
pected DNAPL
Total chlorinated hydrocarbons -
nearly 200,000 ng/L, Suspected
DNAPL
MC - as high as 2,600,000 ng/L,
Suspected DNAPL
Contaminant Concentra-
tions (After Treatment)
(mg/kg= soil or sediment
u,g/L= groundwater)
10/05 to 10/06 PCE ranged
between 1 .7 and 3 ug/L
Total chlorinated hydrocar-
bons^ 1 to 13.9 ng/L
MC - <50 ug/L
Project Status,
Comments
State Rehabilitation
Order (NFA) issued
2/16/07
Awaiting status of
monitoring and
MNA
Final closure
granted 06/08
OTHER
Pasley Solvents and
Chemicals, Inc.,
Hempstead, NY
(Superfund NPL)
SVE/AS 11/97 to
10/02
Surface soil and
subsurface soil,
and GW, Site is
about 75-ft
wide by 275-ft
long with a 60-
ft wide and
400-ft long
contaminant
plume
Clean up site to residential
risk levels and contami-
nant MCLs, EPA Super-
fund NPL
Maximum detected concentra-
tions were:
Surface soil: total VOCs - 603
mg/kg, total SVOCs - 204
mg/kg
Groundwater: Total VOCs - 37
mg/L, TCE - 320 ug/L, Sus-
pected DNAPL
All contaminants of concern
under 1 mg/kg in soil and GW
concentrations ranged from
NO to 4 ug/L
2006 NFA with
discontinuing of
GW monitoring
activity, No institu-
tional control re-
strictions
Source: Project profiles in Appendix A
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Notes:
ug/L micrograms per liter ISTD
bgs below ground surface MADEP
B(a)P benzo(a)pyrene
B(a)P-eq benzo(a)pyrene equivalent MC
DCE dichloroethene MCL
DNAPL dense non-aqueous phase liquid nig/kg
DTSC Department of Toxic Substances Control nig/L
EPA U.S. Environmental Protection Agency MGP
ERH electrical resistive heating MNA
ft foot or feet ND
ft2 square foot or feet NFA
ft cubic foot or feet NFR
GW groundwater NPL
HRC® Hydrogen Release Compound P&T
1C institutional controls PAH
IDEM Indiana Department of Environmental PCE
Management REEL
IEPA Illinois Environmental Protection Agency RCRA
in situ thermal desorption SCE
Massachusetts Department of Environ- S VE
mental Protection SVOC
methylene chloride TACO
maximum contaminant level (EPA)
milligrams per kilogram TCA
milligrams per liter TCDD
manufactured gas plant TCE
monitored natural attenuation TCEQ
non-detectable
no further action TPH
no further remediation TRRP
National Priorities List VC
pump and treat VOC
polycyclic aromatic hydrocarbon yd3
tetrachloroethene
risk-based exposure level
Resource Conservation and Recovery Act
Southern California Edison
soil vapor extraction
semivolatile organic compound
tiered approach to correction action
objectives
trichloroethane
2,3,7,8 tetrachlorodibenzodioxin
trichloroethene
Texas Commission on Environmental
Quality
total petroleum hydrocarbons
Texas Risk Reduction Program
vinyl chloride
volatile organic compound
cubic yard
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3.0 CHALLENGES OF DNAPL CHAR-
ACTERIZATION AND REMEDIA-
TION
As noted above, the physical and chemical
properties of DNAPLs hinder their charac-
terization and remediation. This section fur-
ther explains some of the challenges.2
Locating and Verifying the Presence
of DNAPLs
DNAPLs tend to migrate along the path of
least resistance in the subsurface. Because of
difficulties characterizing a heterogeneous
subsurface, DNAPL source zones are often
difficult to locate, and their size and spatial
distribution difficult to define. Techniques
that can be effective in locating and charac-
terizing DNAPLs include membrane inter-
face probes, ribbon NAPL samplers (e.g.,
the FLUTe™ membrane system), partition
interwell tracer testing, and direct push va-
dose zone and groundwater profiling. In ad-
dition, cone penetrometers can be equipped
with fluorescence detection systems to help
locate creosote and coal tar; Raman spec-
troscopy to identify contaminants and
DNAPL in situ; or GeoVIS to help visually
identify NAPL through downhole video im-
aging.
It is usually difficult to verify the presence
of DNAPLs through direct observation, even
with downhole video imaging. However,
dyes that change color when they encounter
a DNAPL mass or partition into them (e.g.,
Sudan IV) have been used to help identify
the presence of clear DNAPLs. Dyes can be
used during continuous soil coring with a
direct push rig in order to pinpoint DNAPL
masses. The FLUTe™ system, which in-
volves deploying a fabric dye-treated tube
down a borehole, may be used, both in soil
Mention of trade names or commercial prod-
ucts in this report does not constitute endorse-
ment or recommendation for use.
and bedrock, to provide information on the
presence and location of the DNAPL.
The presence of a DNAPL can sometimes
be inferred based on groundwater concentra-
tion data and the "1% of solubility" rule of
thumb (EPA 1992). Under this approach,
DNAPL is suspected to be present when the
concentration of a chemical in groundwater
is greater than 1% of its pure-phase solubil-
ity. For example, when the dissolved phase
of PCE is greater than 1,500 micrograms per
liter (|ig/L)—which is 1% of its pure-phase
solubility of 150,000 (ig/L-PCE is inferred
to be present as a DNAPL. This is a very
conservative estimate since many DNAPL
residual architectures produce plumes with
thin, highly concentrated cores that can be
diluted by conventional monitoring well
construction and sampling techniques. Ap-
pendix B lists the values of 1% solubility
concentrations for several DNAPLs. Note
that for chemical mixtures the solubility of
an individual chemical may be lower than its
pure phase solubility.
For more information: The Interstate Tech-
nology and Regulatory Council's (ITRC)
report, Technology Overview: An Introduc-
tion to Characterizing Sites Contaminated
with DNAPLs (ITRC 2003a), discusses
characterization approaches, data collection
techniques, and investigation methods for
sites contaminated with DNAPLs. EPA's
report, Site Characterization Technologies
for DNAPL Investigations (EPA 2004b),
describes geophysical and non-geophysical
technologies that are useful in locating,
quantifying, and verifying the presence of
DNAPLs.
DNAPL as a Continuing Contaminant
Source and Dissolved Plume Man-
agement
Because DNAPLs slowly dissolve as they
migrate and diffuse into silt and clay, they
can act as continuing sources of groundwa-
ter contamination. The combination of
DNAPL migration and slow dissolution into
groundwater, make DNAPLs difficult to
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eliminate using pump and treat extraction
technologies. Although P&T and other
methods may contain and recover or treat
the dissolved fraction of the contaminant
mass, this fraction can be very small com-
pared to the amount of DNAPL sorbed to
soil or pooled in the source area. It can take
many years or decades for the majority of
the contamination to be recovered by con-
ventional means; thus, cleanup goals can be
difficult to attain when even small amounts
of DNAPL are present at a site.
Debate Over Effectiveness of Partial
Source Removal
DNAPL source zones are hard to locate and
verify; thus, DNAPL source reduction may
achieve only a partial removal of the source
mass. There is an ongoing debate within the
remediation community regarding the utility
of partial source removal or reduction,
where some, but not all, of the DNAPL
source is removed or destroyed. Recent re-
ports have emphasized the need for histori-
cal performance data to better predict the
effectiveness of DNAPL remediation ef-
forts. For example, EPA convened an ex-
pert panel to examine four issues regarding
DNAPL source zone management and
treatment. In its report, The DNAPL Reme-
diation Challenge: Is There a Case for
Source Depletion? (EPA, 2003), the expert
panel concluded that partial mass depletion
from DNAPL source zones has been a vi-
able strategy at certain sites and is likely to
provide benefits at a number of other sites.
However, barriers to more widespread use
of DNAPL source-zone technologies persist.
Additional theoretical analysis and assess-
ment tools, improved monitoring techniques
(site characterization; performance assess-
ment), and field-scale demonstrations that
elucidate benefits of partial source depletion
are needed to provide a more informed basis
for decision-making on whether to under-
take DNAPL source-zone depletion at both
sites with a containment remedy in place
and at new DNAPL sites.
Variation in Cleanup Levels and Clo-
sure Criteria
Cleanup levels and closure criteria vary at
sites contaminated with DNAPL. These cri-
teria include a wide range of quantitative
goals as well as goals that specify qualitative
objectives. Examples of remedial action ob-
jectives established as qualitative criteria
include: "Clean up groundwater to the extent
practicable for the source area;" "Clean up
the source area to the extent practicable;"
and "Remove the source area, then conduct
monitored natural attenuation."
Some state agencies, such as the Illinois
EPA (IEPA), follow a tiered approach to
developing remediation objectives for con-
taminated soil and groundwater. lEPA's
remediation objectives emphasize the pro-
tection of human health, but also take into
account site-specific conditions and land use
to provide flexibility to site owners and op-
erators in developing site-specific remedia-
tion objectives. Each successive tier of the
three-tiered approach is more involved than
the previous tier, with Tier III conducted at
sites where remediation possibilities are lim-
ited due to physical barriers or at complex
sites requiring full-scale risk assessments or
alternative modeling.
4.0 OVERVIEW OF DNAPL REMEDIA-
TION TECHNOLOGIES
In situ technologies being used to remediate
DNAPL sources include:
• In situ thermal technologies,
• In situ chemical oxidation,
• Surfactant/co-solvent flushing,
• In situ bioremediation, and
• Zero valent iron.
Other technologies that have been used to
treat DNAPL sources include direct pump-
ing of DNAPL, dual-phase extraction, exca-
vation, soil vapor extraction (SVE)/air
sparging, containment (e.g., engineered
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slurry walls and permeable reactive zones),
and stabilization/solidification. P&T may be
successful in treating small residual DNAPL
source zones in very permeable soil, but is
not generally cost-effective for treating lar-
ger pools of DNAPL, or large or hard-to-
reach areas of residual DNAPL contamina-
tion because of the long time frames in-
volved.
In general, successful source remediation
depends largely on the location and architec-
ture of the DNAPL. For example, large deep
pools of DNAPL or discharges of DNAPL
to bedrock are especially difficult to address
due to limited accessibility to treatment.
However, small, shallow areas of residual
DNAPL are relatively easy to remediate by
excavation, SVE, or even—as mentioned
above—P&T. The time to reach an NFA de-
cision can be greatly reduced if the source
area and associated highly contaminated
pore water are treated directly, rather than
addressing the dissolved plume only. While
there may be some dispute over the value of
treating a complex source zone, especially if
the goal is to reach maximum contaminant
levels (MCLs), there is general agreement
that targeting the source zone usually can
help clean up a site in a shorter time frame.
Cleanups of the some of the sites profiled in
this report, for example, the Dry Clean USA,
Former Southern California Edison MGP,
Pasley Solvents and Chemicals sites, were
able to achieve MCLs onsite. Others, such
as the Former Cowboy Cleaners and Naval
Submarine Base Kings Bay Site 11, ob-
tained MCLs at a point of compliance.
This section provides an overview of se-
lected technologies that have been used to
treat DNAPL sources, including the use of
combined remedies. The project profiles in
Appendix A illustrate the use of several of
these technologies to achieve site cleanup
goals.3
For more information: More information
about in situ treatment is available in In Situ
Treatment Technologies for Contaminated
Soil (EPA 2006) and the FRTR's compila-
tion of remediation technology assessment
reports
(http://www.frtr.gov/multisitereports.htm).
Also, the DNAPL focus area on EPA's
CLU-IN website contains information.
http: //www .cluin. org/contaminantfocus/defa
ult.focus/sec/Dense Nonaqueous Phase Li
quids (DNAPLsVcat/Treatment Technologi
es/
In situ thermal treatment technologies
employ heat in the source zone to volatilize
or sometimes decrease the viscosity of
DNAPLs to increase their mobility toward
vapor and groundwater extraction wells. In
some applications, such as methylene chlo-
ride contamination, high temperature condi-
tions may destroy DNAPLs through pyroly-
sis or enhanced hydrolysis; however, the
emphasis of thermal remediation is to re-
cover the contaminants from the subsurface
for subsequent destruction , not to try to de-
story them in place.
Various thermal approaches can be used,
including:
• Injection of steam (also referred to as
"steam-enhanced extraction"), or hot wa-
ter to heat the source area.
• Three-phase and six-phase electrical resis-
tive heating (ERH), which applies an
electrical current via electrodes to heat the
source area.
• Thermal conduction (also referred to as
"in situ thermal desorption"), which sup-
plies heat to the soil through steel wells in
the case of deep contamination or with a
blanket that covers the ground surface in
the case of shallow contamination.
Mention of trade names or commercial prod-
ucts in this report does not constitute endorse-
ment or recommendation for use.
For more information: In situ thermal
treatment technologies are described in more
detail in In Situ Thermal Treatment ofChlo-
10
-------
rinated Solvents: Fundamentals and Field
Applications (EPA 2004c).
In situ chemical oxidation (ISCO) tech-
nologies typically inject chemical oxidants
and some times other amendments directly
into the source area where they react with
the contaminants at the dissolved-phase/
liquid-phase interface. This reaction de-
stroys the dissolved-phase DNAPL constitu-
ents and speeds up the dissolution of the
DNAPL at the water/NAPL interface by
keeping the concentration of the dissolved
phase below the DNAPL solubility limit.
Although injection of oxidants is the most
common delivery method, certain circum-
stances such as subsurface heterogeneity,
deep contamination, or low hydraulic gradi-
ent may require other methods to enhance
the delivery of oxidants to the contaminant.
These methods include recirculation, deep
soil mixing, or soil fracturing. Oxidants that
are delivered in the dissolved phase to the
contaminant will not attack the DNAPL di-
rectly.
Four of the more common chemical oxidants
used for DNAPL treatment are sodium and
potassium permanganate, hydrogen peroxide
(when used with iron catalysts, this is gener-
ally referred to as Fenton's chemistry or
Fenton's reagent), ozone, and persulfate (ac-
tivated with either iron, hydroxide, or heat).
The oxidants react with the dissolved-phase
contaminant, breaking chemical bonds and
yielding degradation products, such as car-
bon dioxide, water, and chloride ion, when
the DNAPL is chlorinated.
Surfactant-enhanced ISCO (S-ISCO™) uses
a proprietary nonionic surfactant to help
solubilize DNAPL thus enhancing oxida-
tion.
For more information: ISCO is described
in greater detail in Engineering Issue: In
Situ Chemical Oxidation (EPA 2006) and
Technical and Regulatory Guidance for In
Situ Chemical Oxidation of Contaminated
Soil and Groundwater (ITRC 2001). In ad-
dition, the Environmental Security Technol-
ogy Certification Program and Strategic En-
vironmental Research & Development Pro-
gram are funding a number of bench- and
field-scale studies related to ISCO, as well
as funding development of a technology
practices manual. Summaries of these pro-
jects can be found at http://www.serdp-
estcp.org/ISCO.cfm.
Surfactant and co-solvent flushing tech-
nologies enhance DNAPL removal through
injection and subsequent extraction of
chemicals to solubilize and/or mobilize
DNAPL constituents. Typically, the chemi-
cals used are aqueous surfactant solutions,
which may include electrolytes that aid in
contaminant solubilization or co-solvents
(including alcohols, such as ethanol or iso-
propanol) that lower the interfacial tension.
The chemicals are injected into a system of
wells designed to flood the DNAPL zone
within the aquifer. The chemical "flood" and
the solubilized or mobilized DNAPL are
extracted from the subsurface and separated
and treated above ground. S-ISCO™ com-
bines elements of flushing technology with
ISCO. As noted above, S-ISCO™ may en-
hance chemical oxidation through use of a
proprietary surfactant, which helps solubi-
lize the DNAPL.
Surfactant/co-solvent flushing technology is
described in greater detail in Technical and
Regulatory Guidance for Surfactant/Co-
Solvent Flushing of DNAPL Source Zones
(ITRC 2003b).
In situ bioremediation technologies engi-
neer subsurface conditions to enhance the
biological activity of subsurface microbial
populations. Typically, electron donor sub-
strates, such as lactate or molasses, are in-
troduced into the subsurface using injection-
only or recirculation configurations. The
substrates provide a carbon source which
creates anaerobic conditions that stimulate
native microbes to degrade chlorinated con-
taminants through the process of reductive
dechlorination. Advances are being made in
designing longer-lived substrates (e.g.,
emulsified vegetable oil) that may be more
11
-------
effective in higher-concentration source
zones. Where sufficient populations of the
necessary bacteria are lacking, non-
indigenous microbes can be introduced into
the subsurface (referred to as "bioaugmenta-
tion").
Although more commonly applied to dis-
solved-phase plumes, in situ bioremediation
has been used at sites to treat DNAPL
sources.
For more information: In situ bioremedia-
tion is described in greater detail in Engi-
neered Approaches to In Situ Bioremedia-
tion of Chlorinated Solvents: Fundamentals
and Field Applications (EPA 2000) and
Overview of In Situ Bioremediation of Chlo-
rinated Ethene DNAPL Source Zones (ITRC
2005). Additional detail on design, opera-
tion, and performance monitoring is con-
tained in In Situ Bioremediation of Chlorin-
ated Ethene DNAPL Source Zones (ITRC
2008).
Zero valent iron technologies deliver nano
or micro scale ZVI suspended in a carrier
fluid or as a powder into the subsurface so
they can make contact with the contaminant
of concern. Fluids are usually injected, while
powders are mixed in the soil by augering or
by direct placement in a trench below the
water table. Pneumatic and hydraulic frac-
turing is sometimes used to improve deliv-
ery and distribution of suspended ZVI. In-
troduction of ZVI into the subsurface pro-
motes the chemical reduction of many chlo-
rinated solvents. Use of ZVI to reduce chlo-
rinated solvents has been studied in perme-
able reactive zones that treat the dissolved-
phase contaminants present in the ground-
water plume. An innovative variant of ZVI
technology developed by the National Aero-
nautics and Space Administration emulsifies
the ZVI in vegetable oil. The vegetable oil is
miscible with the DNAPL source and at-
tacks it directly while forming a coating that
prevents it from dissolving without first go-
ing through the oil with its reactant iron.
For more information: More information
on the use of ZVI to treat source zones can
be found on the DNAPL focus area of
EPA's CLU-IN website at http://www.clu-
in.org/contaminantfocus/default.focus/sec/D
ense_Nonaqueous_Phase_Liquids_(DNAPL
s)/cat/Treatment Technologies/p/6. A fact
sheet on nanotechnology is also available at
htto://www.clu-in.org/542f08009.
A combined remedy is a combination of
treatment technologies used simultaneously
or in sequence (also known as a "treatment
train"). There is increasing evidence that
combined remedies can be useful in cleaning
up a site in a much shorter time frame than
traditional methods alone. For example,
SVE plus thermal remediation is more effec-
tive in low-permeability formations than
SVE alone and may eliminate back diffusion
rebound that is often associated with the
remediation of contaminated silts and clays.
A combined remedy approach is also useful
for sites with operating cleanup systems be-
cause one part of the approach is to continu-
ally evaluate if an existing system is still
suited to the site conditions and whether a
more efficient system is available. System
optimization and continuous evaluation
should be an integral part of any operation
and maintenance program.
For more information: A discussion of
combined remedies can be found in Guid-
ance for Optimizing Remedy Evaluation,
Selection, and Design (NAVFAC 2004).
EPA is interested in identifying additional
sites where DNAPLs are present, a reme-
dial technology has been used, and the site
has since reached regulatory closure or is
approaching closure. Please contact Linda
Fiedler at EPA's Office of Superfund Re-
mediation and Technology Innovation to
discuss further, at (703)-603-7194, or e-
mail fiedler.linda@epa.gov.
12
-------
5.0 DNAPL REMEDIATION
PROJECTS
Thirteen remediation projects illustrating
how treatment of the DNAPL source zone
expedited attainment of cleanup goals are
profiled in this report. DNAPL was reported
to have been observed at 3 sites and sus-
pected at 10 sites, based on elevated con-
taminant concentrations in groundwater. At
each site:
• A destruction or removal technology was
used to address the DNAPL source zone;
and
• Regulatory closure was reached with no
long-term monitoring required; or regula-
tory goals have been met, but groundwa-
ter monitoring is still ongoing with the in-
tention that it will not be long term (i.e.,
rebound has not occurred but the regula-
tors want to be sure before abandoning
the monitoring wells).
For quick reference, Table 1 summarizes
information about the remediation projects
profiled in Appendix A. These projects are
not necessarily representative of the range of
DNAPL sites and the treatment projects be-
ing performed today.
In addition to the project profiles, the fol-
lowing sources provide further information
about specific DNAPL-contaminated sites
where aggressive in situ treatment technolo-
gies have been used:
• In Situ Bioremediation of Chlorinated
Ethene DNAPL Source Zones: Case Stud-
ies. ITRC. April 2007.
(http://www.itrcweb.org/Documents/bioD
NPL Docs/BioDNAPL-2.pdf)
• In Situ Treatment of Groundwater Con-
taminated with NAPL Contamination:
Fundamentals and Case Studies. Proceed-
ings of meeting sponsored by EPA and
ITRC, December 2002.
(http://cluin.org/studio/napl 121002/1
• In Situ Thermal Treatment database
(http://cluin.org/products/thermal')
• In Situ Chemical Oxidation database
(http://cluin.org/products/chemox)
• FRTR Cost and Performance Case Stud-
ies (http://www.frtr.gov/costperf.htm)
• State Coalition of Drycleaner Case Stud-
ies (http://www.drycleancoalition.org)
6.0 SUMMARY OF FINDINGS
The following general and technology-
specific findings about DNAPL characteri-
zation and remediation are based on avail-
able information on the field technology
applications highlighted in this paper.
General Findings
The 13 sites profiled in Appendix A include
3 drycleaning establishments, 4 manufactur-
ing or chemical processing facilities, 2
MGPs, and 3 wood treatment sites, as well
as 1 landfill. The majority of the sites (8)
were suspected to have had chlorinated sol-
vents (e.g., PCE, TCE, and/or methylene
chloride) and, in some cases, their degrada-
tion products, in the form of DNAPL or a
dissolved plume. The remaining 5 sites (the
MGP and wood treatment sites) were con-
taminated with creosote or coal tar DNAPL
and in some cases diesel range hydrocarbons
used as carrier for the creosote or penta-
chlorophenol. .
The types of treatment used to address the
DNAPL sources included:
• In situ thermal technologies (six sites)
• Ex situ thermal technologies (one site)
• In situ chemical oxidation (five sites)
• SVE and air sparging (one site)
Source removal through the excavation of
contaminated soil was conducted at three
sites in addition to the subsequent treatment
application. The time span from commenc-
ing in situ treatment to receiving a closure
letter at these sites varied from about one to
eight years.
13
-------
Of the 13 sites examined 7 had restrictions
or conditions placed on closure. For exam-
ple:
• The NFA letter for the Avery Dennison
Site, Illinois, required implementation of
institutional controls.
• The NFA letter for the Former Cowboy
Cleaners Site, Colorado, permitted only
commercial land use.
• The Certificate of Completion for the
Former Southern California Edison MGP
will be signed pending deed restrictions
that prohibit residential use.
Of the 7 sites where groundwater contami-
nation was treated , six had MCLs as goals
and 5 achieved the MCLs. For example:
• Following oxidation treatment the former
Sta-Lube site achieved methylene chlo-
ride concentrations of less than the 50
jig/L MCL goal.
• At the Dry Clean USA site PCE levels
which started out with a maximum de-
tected of 27,300 ng/L were in the ND to
3 (ig/L levels (MCL 5 (ig/L) following
treatment.
• Using SVE and groundwater air sparging
at the Pasley Solvents and Chemicals,
Inc. site total VOCs and TCE were re-
duced from 37 mg/L and 320 ug/L re-
spectively to between ND and 4 (ig/L.
The MCL for TCE is 5 ug/L.
Technology-Specific Findings
In Situ Thermal Treatment - Full-scale in
situ thermal treatment was implemented at
six sites: two manufacturing facilities, one
drycleaner, one MGP, and two wood treat-
ment facilities. Three of the sites were
treated using thermal conduction, two with
ERH, and one with steam injection. The
treated soils primarily were a stratified mix
of relatively low-permeability units such as
silts, clays, and silty sands. One site con-
tained coarser-grained fill material compris-
ing sand, gravel, and cobbles. Volumes
ranging from approximately 50,000 to
500,000 ft3 were treated. The deepest con-
tamination treated was over 145 ft below
ground surface (bgs). Three sites received
closure letters within less than two years of
commencing thermal treatment. Overall,
these projects showed that in situ thermal
treatment was able to remediate sites with
varying subsurface conditions in both the
saturated and unsaturated zones to satisfy
regulatory requirements.
• The Confidential Chemical Manufactur-
ing Facility, Portland Indiana, used in situ
thermal conduction to treat two contami-
nated areas comprising a total volume of
about 135,000 ft3 of saturated and unsatu-
rated soil. The goal was to reduce TCE,
PCE, and 1,1-DCE concentrations from
more than 3,500 mg/kg to less than state
risk-based cleanup goals for industrial
land use (25 mg/kg for TCE, 8 mg/kg for
PCE, and 0.08 mg/kg for 1,1-DCE) in five
months. These goals were met and a NFA
letter was issued by the state.
• The Avery Dennison Site, Illinois, used
ERH to treat approximately 16,000 ft3 of
saturated and unsaturated soil. The goal
was to reduce methylene chloride (MC)
concentrations from more than 50,000
mg/kg to less than the state risk-based
cleanup goal (24 mg/kg) in 11 months.
While institutional controls were imposed
the average soil concentration of .51
mg/kg MC met cleanup goals.
• The Camelot Cleaners Superfund site in
North Dakota used an ERH system to
treat approximately 370,000 ft3 of soil and
groundwater with the deepest zone tar-
geted at 56 bgs. Cleanup goals (3 mg/kg
in soil and 1 mg/L total volatiles in
groundwater) were largely met with one
small area having levels above 3 mg/kg.
The heating and extraction system oper-
ated for 11 months.
• A Former MGP Site in Massachusetts
used in situ thermal conduction to recover
16,000 gallons of coal tar and clean up
about 54,000 ft3 of contaminated soil and
fill in an abandoned gasholder. The goal
to clean up the soil to meet state cleanup
14
-------
levels for unrestricted use was met; how-
ever, the site has institutional controls as a
whole because there are other areas at the
site that could not be cleaned up because
of their proximity to operating equipment
and pipelines. The gas holder project
lasted approximately two years from ini-
tial construction to demobilization.
• In situ thermal desorption was used to
treat about 450,000 ft3 of soil at the For-
mer Wood Treatment Area, California.
The goal was to treat soil containing up to
35,000 mg/kg PAHs and 58 mg/kg PCP to
levels of 0.065 mg/kg (expressed as
benzo(a)pyrene equivalents [B(a)P-eq])
and 2.5 mg/kg PCP. Cleanup goals were
met and the site is open for unrestricted
use.
• Steam with injected air was used at the
Visalia Pole Yard to treat about 300,000
pounds of contaminants. DNAPL (creo-
sote) and LNAPL (diesel range hydrocar-
bons were present at the site. The cleanup
goals of 17 mg/kg and 1 (ig/L penta-
chlorophenol, 0.39 mg/kg and 0.2 (ig/L
benzo(a)pyrene and 0.001 mg/kg and 30
pg/L TCDD equivalent were all achieved
by the end of an air sparging and biovent-
ing polishing step following the steam ap-
plication.
In Situ Chemical Oxidation - The five
ISCO projects were conducted at two dry-
cleaning facilities, a former MGP, a former
chemical manufacturing plant, and a landfill.
A variety of oxidants were used:
• Fenton's reagent (2 sites)
• Permanganate (1 site)
• Sodium persulfate (1)
• Hydrogen peroxide (1 site)
• Ozone (1 site)
The geology at the ISCO sites range from
fine- to medium-grained sand to stiff clay.
Several of the projects involved multiple (up
to four) phases of chemical injection and the
ozone remediation pulsed ozone and oxygen
into the subsurface over a two year period .
Three of the sites received closure letters,
and one will receive a Certificate of Com-
pletion once deed restrictions are recorded.
The landfill site has not yet received an NFA
determination. Although MCLs have been
met at the point of compliance (the site
boundaries) and the onsite plume is ap-
proaching MCLs, groundwater monitoring is
continuing at the landfill to determine when
the onsite plume has met cleanup standards
and ensure compliance.
• The Former MGP Site, Southern Califor-
nia Edison used excavation and in situ
ozonation to reduce total polycyclic aro-
matic hydrocarbons (PAHs) concentra-
tions in soil from 2,500 mg/kg to less than
1.75 mg/kg as B(a)P-eq (the site-specific
risk-based cleanup goal) in approximately
three years. Cleanup goals in groundwater
and soil were met except for an inaccessi-
ble area around a highway foundation.
• The Former Cowboy Cleaners Site, Colo-
rado, used potassium permanganate to re-
duce PCE concentrations in groundwater
from 1,900 (ig/L to 48 (ig/L in approxi-
mately one year. This was sufficient for
the state to issue a NFA with site uses re-
stricted to commercial.
• Dry Clean USA #11502, Florida, used a
combination of P&T, SVE, and hydrogen
peroxide to treat a groundwater plume ap-
proximately 800 ft by 300 ft and up to 68
ft deep. The goal was to reduce PCE con-
centration in the groundwater to 3 (ig/L,
or less. The P&T and SVE systems oper-
ated about 3.5 years. They were followed
by a one-month application of peroxide
for polishing. One year PCE concentra-
tions varied between 1.7 and 3 (ig/L and
the state issued an NFA with unrestricted
use.
• Four injections of Fenton's reagent were
conducted from 1998 to 2001 at the Naval
Submarine Base Kings Bay, Site 11,
Georgia. Groundwater P&T to contain the
groundwater plume (700 ft by 200 ft and
30 to 40 ft deep) within the site bounda-
15
-------
ries had failed, and modeling suggested
that if the plume concentrations were
lowered to 100 ug/L total chlorinated hy-
drocarbons, MNA would treat the remain-
ing dissolved contaminants. ISCO re-
duced levels to the target, but made the
aquifer aerobic in the injection areas and
some distance downgradient. To return
the now aerobic section of the aquifer to
reducing conditions, subsequent injections
of emulsified oil were made and these
created the necessary anaerobic condi-
tions for degradation. As of 2004, the lev-
els have been reduced to less than 13.9
ug/L. MNA is the final corrective action
for remaining groundwater contamination
at the site. MCLs have been met at the site
property line for all contaminants having
them.
• Following large-auger excavation of the
source area, persulfate catalyzed with hy-
drogen peroxide was injected at the Sta-
Lube site, California, to treat a methylene
chloride plume. Due to the presence of
DNAPL, a 80-ft by 30-ft plume beneath
the building was not treated by the previ-
ous SVE and P&T systems. Concentra-
tions were reduced from a maximum of
18,000 ug/L to the cleanup goal of 50
ug/L within 5 months. Final closure was
granted in June 2008.
SVE and Air Sparging - Contamination at a
solvent transfer facility was cleaned up prin-
cipally by SVE and air sparging.
• The Pasley Solvents and Chemicals
Superfund Site in New York used
SVE/AS to treat soil source zones (total
VOCs up to 603 mg/kg) and a 60-ft by
400-ft-long chlorinated solvents plume
(TCE up to 320 ug/L). All cleanup goals
were met including Maximum
Contaminant Levels (MCLs) for
groundwater contaminants. A NFA letter
was issued with no institutional controls
requirements. The remediation took 60
months with 18 months of subsequent
groundwater monitoring.
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http: //www .e step. org/documents/techdocs/IS
O_Report.pdf
Ruling, Scott and Bruce Pivetz. 2006. Engi-
neering Issue: In-Situ Chemical Oxidation,
EPA/600/R-06/072.
http://www.epa.gov/ada/download/issue/600
R06072.pdf
ITRC. 2001. Technical and Regulatory
Guidance for In Situ Chemical Oxidation of
Contaminated Soil and Groundwater.
http://www.itrcweb.org/Documents/ISCO-
2.pdf
Watts, R., Frank Loge, and Amy Teel. 2006.
Improved Understanding of Fenton-Like
Reactions for the In Situ Remediation of
Contaminated Groundwater Including
Treatment of Sorbed Contaminants and De-
struction of DNAPLs. Strategic Environ-
mental Research and Development Program.
http://docs.serdp-estcp.org/viewfile.cfm7Do
c=ER 1288 FRpdf
In Situ Surfactant/Co-Solvent
Flushing
ITRC. 2003b. Technical and Regulatory
Guidance for Surfactant/Co-Solvent Flush-
ing of DNAPL Source Zones.
http://www.itrcweb .org/gd DNAPLs.asp
In Situ Thermal Treatment
EPA. 2004c. In Situ Thermal Treatment of
Chlorinated Solvents - Fundamentals and
Field Applications. EPA 542-R-04-010.
http://cluin.Org/techfocus/default.focus/sec/T
hermal_Treatment:_In_Situ/cat/Application/
Davis, E. 1998. Ground Water Issue: Steam
Injection for Soil and Aquifer Remediation.
EPA 540/S-97/505, 16pp.
http://www.epa.gov/ada/download/issue/stea
minj .pdf
Davis, E. 1997. Ground Water Issue: How
Heat Can Enhance In-Situ Soil and Aquifer
Remediation: Important Chemical Properties
and Guidance on Choosing the Appropriate
Technique. EPA 540/S-97/502, 18 pp.
http://www.epa.gov/ada/download/issue/hea
tenh.pdf
Gavaskar, Arun, Mohit Bhargava, and
Wendy Condit. 2007. Final Report: Cost and
Performance Review of Electrical Resis-
tance Heating (ERH) for Source Treatment.
18
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Naval Facilities Engineering Service Center,
TR-2279-ENV, 133 pp.
http://costperformance.org/remediation/pdf/
Navy-ERH Review.pdf
Zero-Valent Iron Injection
EPA, 2008. Nanotechnology for Site Reme-
diation. EPA 542-F-08-009.
http://www.clu-in.org/542f08009
EPA. 2004. Demonstration Injection of In
Situ Dehalogenation of DNAPL through
Injection of Emulsified Zero-Valent Iron at
Launch Complex 34 in Cape Canaveral Air
Force Station Florida: Innovative Technol-
ogy Evaluation Report. EPA/540/R-07/006.
http://www.epa.gOv/nrmrl/pubs/540r07006/5
40r07006.pdf
U.S. Department of the Navy. 2003. Final
Cost and Performance Report - Feroxsm In-
jection Technology Demonstration Parcel C,
Remedial Unit C4, Hunters Point Shipyard,
San Francisco, California, July 11, 2003.
DS.A013.10177
http://costperformance.org/pdf/20040701 3
52.pdf
Combined Remedies
NAVFAC. 2004. Guidance for Optimizing
Remedy Evaluation, Selection, and Design,
User's Guide. UG-2060-ENV.
http: //www .clu-in. org/download/remed/
Navv-OPT-doc-UG-2060-OPT.pdf
NOTICE AND DISCLAIMER
Preparation of this report has been funded
wholly or in part by EPA under Contract
Number 68-W-03-038. Mention of trade
names or commercial products does not con-
stitute endorsement or recommendation for
use. A PDF version of this report is avail-
able for viewing or downloading from the
Hazardous Waste Cleanup Information (Clu-
In) web site at http://clu-in.org. For more
information regarding this report, contact
Linda Fiedler of EPA's Office of Superfund
Remediation and Technology Innovation, at
(703)603-7194 or fiedler.linda@,epa.gov.
19
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Appendix A
DNAPL Remediation Project Profiles
The DNAPL remediation projects profiled quantity of DNAPL originally present. Most
here were conducted as full-scale remedia- of these sites have reached regulatory
tion projects rather than research demonstra- cleanup goals and require no further action
tions, and the sampling efforts typically with no further monitoring.
were not sufficient to establish the exact
20
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Confidential Chemical Manufacturing
Facility, Portland, Indiana
Technology Used: In situ conductive heat-
ing and vacuum (in situ thermal desorption)
Regulatory Program: State Voluntary
Cleanup Program
Project Duration: July to December 1997
Information Last Updated: 2008
Site Information: The 16-acre chemical
manufacturing facility is located in the
southern portion of Portland, Indiana, south-
east of the Salamonie River. Since 1886, the
area has been used as a lumberyard for the
manufacture of wheels, hard rubber products
used in automobiles, and plastic exterior
automobile parts. The site has four buildings
including a north plant building that is cur-
rently being used part-time for the rework-
ing of automotive parts. A sampling event
conducted in June 1994 revealed the pres-
ence of volatile organic compounds (VOCs)
in soil and groundwater. Additional investi-
gations performed from July 1995 to Febru-
ary 1996 confirmed the presence of VOCs in
subsurface soil of two areas near the north
plant building. Contamination in one area
covered 150 ft by 50 ft to a depth of 18 ft,
and the contamination in the other extended
to an area of 30 ft by 20 ft to a depth of 11
ft.
Contaminants: Chlorinated solvents (PCE,
TCE, and 1,1-DCE) were detected in the
unsaturated zone at levels up to 3,500
mg/kg, 79 mg/kg, and 0.65 mg/kg, respec-
tively. The elevated concentration of PCE
suggested the presence of DNAPL. VOCs
were not found above the cleanup goals in
groundwater after treatment.
Hydrogeology: The facility overlies a het-
erogeneous combination of fill, clayey sand,
and construction debris, to a depth of about
7 ft. Tills, consisting of moist, silty clay ex-
tend to a depth of 18 to 19 ft bgs. Fine to
coarse gray sand with some gravel are found
beneath the till at depths greater than 19 ft
and extending to a maximum of 30 ft. The
estimated hydraulic conductivity of the till
was 10"8 cm/s. Groundwater occurs at ap-
proximately 22 ft bgs.
Project Goals: Soil cleanup goals were es-
tablished based on the Indiana Department
of Environmental Management (IDEM) Tier
II Cleanup Goals for Industrial Land Use
http://www.in.gov/idem/5516.htm
Cleanup Criteria for Confidential Chemi-
cal Manufacturing Facility, Portland,
Indiana (Tier II)
Contaminant
1,1 -DCE
TCE
PCE
Tier II Cleanup
Level for Soil
(mg/kg)
0.080
25
8
Cleanup Approach: Site investigations be-
gan in 1994. The in situ conductive heating
system began operation in July 1997 to treat
contaminated soil in two source areas. A
total of 130 heater/vacuum wells were in-
stalled on a 7.5-ft triangular spacing in the
first source area to a depth of 19 ft. Fifteen
heater/vacuum wells were installed on a 7.5-
ft triangular spacing to depths of 12 ft in the
second source area. The heaters in these
wells operated at a temperature of 1,400 -
1,600°F, to raise the subsurface tempera-
tures within the treatment zone to an average
of275°F.
The heater/vacuum wells also extracted soil
gas. Off-gases were treated with a flameless
thermal oxidizer, cooled by a heat ex-
changer, and then passed through a carbon
adsorption bed. Off-gases were monitored
for hydrogen chloride, which was used as an
indicator of the decomposition of chlorin-
ated solvents. Off-gases were treated with an
1800 standard cubic feet per minute (scfm)
flameless thermal oxidizer with an operating
temperature range of 1,800-1,900°F, cooled
by a heat exchanger, then passed through a
carbon adsorption bed.
21
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To determine the effectiveness of the treat-
ment system, about 50 soil samples were
collected from the coldest locations within
the treatment zone farthest from each heater
well and analyzed for VOCs. Based on the
results, heating was discontinued in Decem-
ber 1997. Confirmation sampling was con-
ducted after monitoring the soil tempera-
tures for six months.
Project Time Line:
1994 - 1996 Site investigations performed
7/97 - 12/97 In situ conductive heating per-
formed
Project Results: Following treatment, re-
sults of confirmation sampling showed that
PCE and TCE concentrations were below
the cleanup goals. No confirmation samples
were available for the smaller, 1,1-DCE con-
taminated zone area. The table below shows
contaminant concentrations at locations that
had relatively higher concentrations before
treatment. Based on the results, the IDEM
issued a NFA letter for this property. Infor-
mation about the date or conditions of the
NFA letter was not available.
Comparison of Selected Pre-Heating and Post-Heating Contaminant Concentrations in Soil
Sampling Location
SA 13
GP31
SA4
SB 20
SB 19
Depth
(ft)
9-10
15-16
4-5
4-5
12-14
Contaminant Concentration (mg/kg)
Before Treatment
PCE
3,500
570
23
2.9
76
TCE
79
Not sampled
0.25
0.67
1.6
After Treatment
PCE
0.011
0.18
0.530
0.046
0.048
TCE
0.020
0.008
ND
ND
ND
ND - non-detect (detection limits not provided)
Source: Federal Remediation Technologies
Roundtable. 2003. "Cost and Performance
Report: In situ Conductive Heating at the
Confidential Chemical Manufacturing Facil-
ity, Portland, Indiana."
http://costperformance.org
22
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Avery Dennison Site, Waukegan, Illinois
Technology: ERH
Regulatory Program: Illinois EPA Site
Remediation Program
Project Duration: December 1999 to No-
vember 2000
Information Last Updated: 2008
Site Information: The Avery Dennison site
is located in the Waukegan-Gurnee Indus-
trial Park in Waukegan, Illinois. Film coat-
ing operations were performed at this site
from 1975 to 1992. MC was used in these
operations and transferred to above-ground
storage tanks via underground piping. Site
investigations showed the occurrence of MC
in the soil and groundwater in several areas
of the site.
Contaminants: Approximately 16,000 ft3 of
soil was contaminated with MC to depths as
great as 24 ft bgs. Concentrations of MC
ranged to a high of 50,000 mg/kg and aver-
aged 1,900 mg/kg. Information about the
concentration of MC in groundwater was not
available.
Hydrogeology: The geology underlying the
two-acre site is predominantly heterogene-
ous silty-clay glacial till to a depth of about
180 ft bgs. An 8-ft-thick running sand unit
occurs around 22 ft bgs. Groundwater is
typically found around 25 ft bgs with
perched water units encountered at as shal-
low as 6 ft bgs. Bedrock is found at depths
ranging from 180 to 270 ft bgs.
Project Goals: The remediation objective at
the Avery Dennison site was to reduce the
concentration of MC in the soil to below 24
mg/kg, based on lEPA's Tiered Approach to
Corrective Action Objectives.
Cleanup Approach: The treatment area
was divided into 20 treatment cells. For each
treatment cell, electrodes were installed
around the perimeter to a depth of 24 ft. A
total of 95 electrodes were installed includ-
ing six below an active street, and 16 inside
the existing building. Two thermocouples
were installed in the center of each treatment
cell, at the shallowest (4 ft bgs) and deepest
levels of contamination (24 ft bgs). In addi-
tion, 34 vacuum extraction wells and five
horizontal wells were installed to extract soil
vapor and steam. The designed power input
was 1,250 kilowatts (kW). After six months
of operation, target soils reached an average
temperature of 80°C, with central areas
reaching boiling temperatures.
Project Time Line:
1985 - Removal Action
1988 - Installation of grout curtain around
the former bulk storage area
1991-1994 - Soil vapor extraction per-
formed at former bulk storage area. This was
ineffective and discontinued at the end of
1994.
1992-1994 - Pump and treat of groundwater
1994-1998 - Air sparging of groundwater
12/99 - ERH initiated in western portion
6/00 - ERH initiated in eastern portion
11/00 - ERH completed
4/01 - IEPA issued NFR letter
Project Results: Very little MC was recov-
ered by the vacuum systems. Analysis of
soil samples collected in areas of known
high MC concentrations had high concentra-
tions of chloride ions indicating that the MC
was destroyed in place by hydrolysis. A total
of 125 soil samples were collected and ana-
lyzed for MC. The average MC concentra-
tion in soil was reduced to 2.51 mg/kg,
which is below the cleanup goal. Based on
the confirmatory sampling results, in April
2001, the IEPA issued a NFR letter, which
specified several engineering and institu-
tional controls, including a prohibition on
installing and using potable water supply
wells in a specified area around the site. Re-
development was restricted to industrial/
commercial reuse, and the site was subse-
23
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quently redeveloped into an office and Federal Remediation Technologies Round-
warehouse park, table. 2003. "Cost and Performance Report:
Electrical Resistive Heating at the Avery
Sources: Current Environmental Solutions Dennison Site, Waukegan, Illinois."
website: http://www.cesiweb.com. http://costperformance.org.
24
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Camelot Cleaners, West Fargo, North
Dakota
Technology: ERH
Regulatory Program: U.S. EPA, Region 8
Superfund
Project Duration: June 2004 to July 2006
Information Last Updated: 2008
Site Information: Camelot Cleaners is an
operating drycleaner that uses PCE as its
cleaning solvent. The cleanup footprint is
about 10,300 ft2 with depths of the contami-
nation ranging to 56 ft bgs. The area in-
cludes part of the yard of an occupied resi-
dence.
Contaminants: PCE and its degradation
products (TCE and DCE) were detected in
soil and groundwater. PCE concentrations
were up to 2,200 mg/kg in soil and 89 mg/L
in groundwater. The contaminated volume
of soil was estimated to be about 370,000 ft3
with the deepest zone targeted at 56 bgs.
Hydrogeology: Camelot Cleaners is under-
lain by low-permeability clay with goethite
infilling of joints and fractures. Groundwater
occurs between 3 and 7 ft bgs and tends to
be perched. The regional aquifer is at ap-
proximately 60 to 70 ft bgs.
Project Goals: The project goals were to
reduce PCE levels to less than 3 mg/kg in
soil and total VOCs to less than 1 mg/L in
groundwater.
Cleanup Approach: The deployment of the
six-phase electrical heating system included
56 multi-zone electrode/vent assemblies and
several horizontal soil vapor extraction
wells. In especially clayey horizons, the ex-
traction wells were augmented with dual
vacuum extraction wells. Soil temperature
was recorded at ten temperature monitoring
piezometers. Nine multi-level monitoring
wells were installed around the perimeter of
the site to monitor existing conditions and
cleanup success, and to ensure that any sub-
surface migration of contaminants would be
detected. The system removed about 5,188
pounds of contaminants.
Project Time Line:
6/04 - Site construction began
2/05 - Heating began
11/05 - Heating was stopped and the hori-
zontal extraction well system was turned off
1/06 - Dual vacuum extraction well system
was turned off following cool-down period
7/06 - EPA removed the electrode and vent
assemblies, and after discussion with the
North Dakota Department of Health, the
groundwater monitoring wells were aban-
doned.
Project Results: A total of 5,188 pounds of
VOC mass was removed within one year of
ERR operation. EPA confirmation sampling
indicated that soil contamination had been
reduced by 99.96 to 100% and groundwater
concentrations had been reduced by 99.98%.
Only one area had concentrations of PCE
over 3 mg/kg, and all the groundwater sam-
ples were under 1 mg/L. The site is now in a
no further action, no further groundwater
monitoring required status.
Sources: DNAPL Remediation In Low
Permeability Clays Camelot Cleaners Super-
fund Site Fargo, ND
http://www.cesiweb.com.
Personal communication with Joyce Acker-
man, U.S. EPA Region 8, April 27, 2007
and April 28, 2008.
25
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Former MGP Gasholder, North Adams,
Massachusetts
Technology: Thermally enhanced free
product recovery, in situ thermal solidifica-
tion (ISTS), and in situ thermal desorption
(ISTD)
Regulatory Program: Massachusetts De-
partment of Environmental Protection
Project Duration: August 2003 to June
2005
Information Last Updated: 2008
Site Information: The former MGP in
North Adams, Massachusetts, operated from
the 1860s to the 1950s. When the 18-ftdeep,
62-ft-diameter gasholder was decommis-
sioned, it was backfilled with soil and debris
enclosing a volume of approximately 2,013
yd3. Based on limited soil investigations
within the gasholder, residual coal tar was
present throughout the soil. The bottom four
feet of soil were saturated with coal tar
DNAPL.
Contaminants: The contaminants of con-
cern at the site are semivolatile organic
compounds associated with coal tar. The
maximum concentrations of some of the
contaminants detected were: benzo(a)pyrene
(650 mg/kg), naphthalene (14,000 mg/kg),
benzene (6,200 mg/kg), and TPH (230,000
mg/kg).
Hydrogeology: The contents of the gas-
holder comprise a mixture of sand, gravel,
cobbles, and other fill material. The regional
aquifer is located beneath. Perched ground-
water was found within the gasholder at 3 ft
bgs.
Project Goals: The project goals, derived
from a human health risk assessment, de-
pended on the depth. Within 6 to 15 ft bgs,
the goals were to eliminate DNAPL and re-
duce contaminants below the Massachusetts
Contingency Plan's upper concentration lim-
its for a potential construction worker expo-
sure scenario, e.g., benzo(a)pyrene (300
mg/kg), naphthalene (10,000 mg/kg), ben-
zene (2,000 mg/kg), and TPH (10,000
mg/kg). Within the bottom of the gasholder
(15 to 18 ft bgs), the goal was to eliminate
DNAPL so that there would not be a risk of
future release of DNAPL to groundwater.
The regional aquifer occurs below the base
of the gasholder.
Cleanup Approach: Three levels of heating
were conducted: 1) Low-temperature heat-
ing for thermally enhanced free product re-
covery of coal tar from the gasholder; 2)
Moderate-temperature heating for ISTS of
coal tar at the bottom of the gasholder; and
3) High-temperature heating and ISTD in
the midsection of the gasholder (6-15 ft
bgs).
Twenty-five thermal wells—19 heater-only
wells and 6 heater-vacuum wells—were in-
stalled to the base of the gasholder. Prior to
heating, 100,000 gallons of water were
pumped from the gasholder and treated by
passing it through an oil/water separator fol-
lowed by clay-carbon media and activated
carbon.
Next, low-temperature heating was con-
ducted to remove free-flowing coal tar
DNAPL. Air was injected into each thermal
well to maintain oxidizing conditions within
the lower part of the gasholder throughout
the remediation process. Thermocouple ar-
rays were used to ensure that subsurface
temperatures within the treatment zone
reached target goals.
The temperature was then raised to or
slightly above the boiling point of water to
eliminate 16,000 gallons of additional
DNAPL via ISTS. The temperature was
raised again to 325°C to volatilize, boil, py-
rolize, and oxidize the remaining contami-
nants through ISTD. Vapors were treated
using a regenerative thermal oxidizer with a
vapor phase activated carbon unit for
backup.
26
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Project Time Line:
11/03 - Site construction
2/04 - Dewatering tar recovery
7/04 to 3/05 - Full power heating
6/05 - Demobilization
Project Results: The intermediate heating
recovered 16,000 gallons of coal tar. Within
the upper portion of the gasholder (6 to 15 ft
bgs), full heating brought average concentra-
tions of all constituents of concern below the
Massachusetts upper concentration limits.
The final averages were: 0.33 mg/kg
benzo(a)pyrene, 5.7 mg/kg naphthalene,
0.35 mg/kg benzene, and 43.15 mg/kg TPH.
Within the bottom of the gasholder (15 to 18
ft bgs), full heating reduced concentrations
of benzene to 0.95 mg/kg and naphthalene to
70 mg/kg. In the process, the previously liq-
uid coal tar was thermochemically solidified
to material that had the appearance of as-
phalt and no longer a DNAPL consistent
with the findings of Hayes (2002).
All goals for the project were met. The
owner filed for an Activity and Use Limita-
tion to the Massachusetts Department of
Environmental Protection, rather than a No
Further Action Determination, because un-
restricted use was not obtainable for the site
as a whole. Elsewhere on the MGP property,
contaminants were allowed to remain in
place beneath a cap.
Sources: Fact sheet. Commercial Project—
MGP Gasholder. TerraTherm® Inc.
http: //www .terratherm .com
Baker, Ralph S., et al. In Situ Thermal De-
struction (ISTD) of MGP Waste in a Former
Gasholder: Design and Installation.
http://www.terratherm.com/resources/TechP
apers/Terratherm%20Paper%205 5 6%20-
%20Monterev.pdf
Baker, Ralph, et al. Demonstration of Three
Levels of In-Situ Heating for Remediation
of a Former MGP Site.
http://www.terratherm.com/resources/TechP
apers/Baker%20et%20al.%202006%20Mont
erev%20MGP.pdf
Hayes, Thomas D. 2002. Development of In
Situ Thermochemical Solidification for the
Risk Based Treatment of Coal-Derived
Dense Nonaqueous Phase Liquids. GRI-
04/0215. Prepared by Gas Technology Insti-
tute, Des Plaines, IL for Gas Research Insti-
tute.
27
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Former Wood Treatment Area, Alham-
bra, California
Technology Used: In situ thermal desorp-
tion (ISTD)
Regulatory Program: Voluntary action
under California Department of Toxic Sub-
stances Control (DTSC) Expedited Reme-
dial Action Program
Project Duration: May 2002 - February
2007
Information Last Updated: 2008
Site Information: Southern California Edi-
son's 3 3-acre facility in Alhambra currently
is used for storage, maintenance, and em-
ployee training. A portion of the facility, the
2-acre former wood treatment area, was
used from approximately 1922-1957 to treat
utility poles by immersing them in creosote.
Pentachlorophenol (PCP) was also used
briefly before operations were shut down.
Spills and/or leaks led to the contamination
of underlying soil.
Contaminants: PAHs and PCP were pre-
sent in site soil at maximum concentrations
of 35,000 mg/kg and 58 mg/kg, respectively,
and mean concentrations of 2,306 mg/kg
and <1 mg/kg. Dioxins, expressed as
2,3,7,8-tetrachlorodibenzodioxin (TCDD)
Toxic Equivalency Quotient (TEQ), were
present at a maximum concentration of
0.194 mg/kg and mean concentration of
0.018 mg/kg. The PCP used at the site is
believed to be the source of the dioxins. Ap-
proximately 16,500 yd3 of contaminated soil
required treatment.
Hydrogeology: The facility is underlain by
fill and silty sand interbedded with sand, silt,
and clay. The water table is greater than 240
feetbgs.
Project Goals: The following table shows
the soil remediation standards for the treat-
ment area.
Cleanup Criteria for the Former Wood
Treatment Area
Contaminant
Total PAHs
Pentachlorophenol
Dioxins
Soil Remediation
Standard (mg/kg)
0.065*
2.5
0.001**
*Expressed as (B(a)P-eq)
** Expressed as 2,3,7,8-TCDD TEQ.
Cleanup Approach: The ISTD process in-
volved simultaneous application of thermal
conduction heating and vacuum to treat the
contaminated soil in situ. A total of 785
thermal wells (131 heater-vacuum and 654
heater-only wells) were installed on a hex-
agonal grid within the 31,430 ft2 target
treatment zone. The heater-vacuum wells
were installed at the center of each hexagon,
and the heater-only wells were installed at 7-
ft intervals on center. The wells ranged from
7 to 102 ft in depth.
To avoid exceeding the local power supply,
treatment proceeded in two phases. Prior to
Phase 1 of heating, a light aggregate cement
surface was poured over the wellfield for
insulation and to provide a vapor seal that
prevented steam and vapor loss to the at-
mosphere. To improve the insulation during
Phase 2, a similar cement was poured above
and below a layer of insulation board.
The target soil temperature of 620°F was
attained in approximately 6 months of Phase
1 heating and was maintained for three days.
Gases emerging from the heated soil were
collected under vacuum and conveyed to an
air quality control system, which consisted
of a thermal oxidizer, heat exchanger to cool
the gases, and vessels of granular activated
carbon in series. Following wellfield cool-
down, Phase 2 heating was initiated. Con-
tinuous emissions monitoring, vapor sam-
pling, and source tests were used to monitor
system performance.
28
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Project Time Line:
00 - Treatability study and selection of con-
ductive heating
6/02 - 4/04 Phase 1 In Situ Thermal Desorp-
tion treatment
7/04 - 9/05 Phase 2 In Situ Thermal Desorp-
tion treatment
3/06 - Demobilization from site
2/8/07 - DTSC issues Remedial Action
Completion Report Approval and Certifica-
tion
Project Results: The site-wide mean
benzo(a)pyrene equivalent and 2,3,7,8
TCDD TEQ concentrations in soil were re-
duced from 30,600 ug/kg and 18 ug/kg, re-
spectively, to 59 ug/kg and 0.11 ug/kg.
These concentrations are below their respec-
tive 65 ug/kg and 1 ug/kg cleanup goals.
The mean PCP soil concentration was 1.25
mg/kg. PCP was not detected in any of the
soil samples at or above the remediation
goal of 2.5 mg/kg.
Dioxin emissions were 0.0084 ng TEQ/dsm3
compared to the 0.2 ng TEQ/ dsm3 standard.
In February 2007, the California Department
of Toxic Substances Control issued a Reme-
dial Action Completion Report Approval
and Certification stating that the treatment
area had been remediated to allow for unre-
stricted land use and that no further action
was required. The cost of treatment was es-
timated to be 40% lower than the cost for
excavation.
Sources: Fact sheet: Former Wood Treat-
ment Area. TerraTherm® Commercial Pro-
ject-California.
http: //www .terratherm .com/Case Studie s/WS
%20Final%20Alhambra%20Sheet.pdf
Baker, Ralph S. Devon Tarmasiewicz, and
John M. Bierschenk (TerraTherm, Inc.),
Jennie King and Tony Landler (Southern
California Edison), and Doug Sheppard
(Lopez and Associates Engineers). 2007.
Completion of In-Situ Thermal Remediation
of PAHs, PCP, and Dioxins at a Former
Wood Treatment Facility. Presented at IT3
'07 Conference, May 14-18, 2007 in Phoe-
nix, AZ.
http://www.terratherm.com/resources/TechP
apers/07-A-88-AWMA-IT3-
Baker%20rev%20a.pdf
29
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Visalia Pole Yard, Visalia, California
Technology Used: Grout wall, pump and
Treat (P&T), in situ thermal desorption
(steam), and excavation
Regulatory Program: US EPA Superfund
NPL site with state lead
Project Duration: 1976 to 2008
Information Last Updated: February 2009
Site Information: Southern California Edi-
son operated a 20 acre fabrication yard
(Visalia Pole Yard) to produce wooden
poles for use in the distribution of electricity
throughout the utility's service territory from
1925 to 1980. Western red cedar trees were
logged and transported to the yard, de-
barked, shaped, and chemically preserved,
Until 1968, chemical preservation consisted
of immersion of the poles in heated bulk
creosote. From 1968 to cessation of opera-
tions, a solution of pentachlorophenol and
diesel was substituted as the wood preserva-
tive (DTSC 2005).
Contaminants: Substantial releases of creo-
sote which contains numerous polycyclic
aromatic hydrocarbons including benzo(a)-
pyrene, pentachlorophenol (PCP), which
contains polychlorinated dibenzo-p-dioxin
and furan impurities, and diesel fuel used as
a carrier fluid for the PCP have occurred.
Other contaminants of concern include chry-
sene, 2-methylnaphthalene, naphthalene, and
phenanthrene (EPA 1994).
Hydrogeology: The sediments underlying
the VPY are composed of alluvial-fan de-
posit from the Kaweah River and its di-
stributaries. The important hydrostrati-
graphic units beneath the site are as follows:
the shallow aquifer (30 to 50 feet bgs; dewa-
tered since the 1980s), the shallow aquitard
(50 to 75 feet bgs), the intermediate aquifer
(75 to 100 feet bgs), the intermediate aqui-
tard (100 to 125 feet bgs), and the deep aqui-
fer (125 to about 180 feet bgs). Aquitards
generally consist of silty materials whereas
aquifers are composed of sand. Testing of
the intermediate aquifer indicated a trans-
missivity of approximately 50,000 gallons
per day per foot (gpd/ft) and the shallow
aquitard restricts vertical movement of the
groundwater when saturated. Short-term
pumping from the deeper aquifer affects
water in the intermediate aquifer (DTSC
undated).
Project Goals: The following table shows
the remediation goals for several of the con-
taminants of concern.
Cleanup Goals
Parameter
Pentachlorophenol
Benzo(a)pyrene
TCDDequivalent1
Soil
17 mg/kg
0.39
mg/kg
0.001
mg/kg
Groundwater
lug/L
0.2 ng/L
30pg/L
1 Dioxin concentration expressed as 2,3,7,8-
tetrachlorodibenzodioxin
Source:DTSC 2005
Cleanup Approach: Excavation and dis-
posal of affected soils has occurred on nu-
merous occasions beginning in 1972.
Cleanup of the groundwater began in 1975
with the installation of a pump and treat sys-
tem. In 1977 a slurry wall was built and
keyed into the shallow aquitard to about 60
feet bgs (DTSC undated).
In 1997 it was decided to use in situ steam
desorption as a means for remediating the
source zones. The system applied steam and
air to the subsurface and the steam front was
monitored using electrical resistance tomo-
graphy. The steam remedy operated in two
phases, between May 1997 and June 2000.
Phase 1 operations focused on the interme-
diate aquifer, with injection and extraction
wells screened between 80 and 100 feet bgs.
Phase 2 operations began in November 1998
and included steam injection and extraction
below the intermediate aquitard, with injec-
tion wells screened between 125 and 145
feet bgs. Phase 2 operations continued until
June 2000, when a precipitous drop in the
30
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rate of removal of WTCs was measured
(DTSC undated).
Following cessation of the steam treatment,
the enhanced biological degradation system
was installed and operated (SCE, 2001) to
augment existing physical processes that
were initiated by the steam treatment and to
encourage natural biological processes to
flourish. This system was in operation from
June 2000 until March 2004. It included va-
dose zone bioventing and saturated zone
biosparging, coupled with continued
groundwater pump-and-treat operations.
Construction completion of the enhanced
Project Time Line:
1972—onward Excavation and removal ac-
tivities
1975—2004 Pump and treat
1976-1977—Placement of slurry wall
May 1997—June 2000 Two phase steam
injection
June 2000—March 2004 Enhanced biologi-
cal degradation system
July 2006 Removal of PCP hotspot (ap-
proximately two-thirds cubic yard)
May 2007 Covenant to Restrict Use of
Property Environmental Restriction
Project Results: While the cleanup did not
leave the land open to unrestricted
use, soil cleanup goals were met in
the first ten feet of the subsurface.
This is the interval considered nec-
essary for construction purposes of
commercial or industrial properties
(SCE 2008).
An Aerial View of the Visalia Site. Injection Wells are Shown
in Magenta circles. Extraction Wells are Yellow squares.
Conrtesv: DOE
biological degradation system was docu-
mented in the 2001 Preliminary Close Out
Report (DTSC undated).
A post-remediation soil investigation of the
surface soils was conducted at this site in
November 2004. Tetrachlorodibenzo-p-
dioxin (TCDD) was detected slightly above
the cleanup standards at four locations. As a
result of the 2005 Five-Year Review, con-
taminated surface soil (soil between zero
and ten feet below grade) was removed in
July 2006 and verified with confirmatory
sampling to be below the cleanup standards
prescribed in the ROD (DTSC undated).
The steam remediation effort re-
moved approximately 1,330,000
pounds of organic chemicals from
the subsurface (SCE 2008).
The pump and treat system com-
bined with the bio enhancement
system polished the groundwater to
an extent that risk based concentra-
tion goals were met as well as the three
MCL values (DTSC undated).
The City of Visalia has indicated an interest
in purchasing the property, following delist-
ing, for an expansion of their current Gen-
eral Services operations (DTSC undated).
Sources: DOE. 2000. Hydrous Pyrolysis
Oxidation/Dynamic Underground Stripping,
EM-0504, 26 pp.
http://www.osti.gov/bridge/product.biblio.js
p?osti id=766922
31
-------
DTSC. undated. Final Close Out Report
Southern California Edison Visalia Pole
Yard Superfund Site Visalia, Tulare County,
California, 11 pp.
http: //www .envirostor. dtsc. ca. gov/public/pro
file report.asp?global id=54490002
DTSC. 2005. Southern California Edison
Company, Visalia Pole Yard Superfund Site,
5-Year Review, 14 pp.
http://www.envirostor.dtsc.ca.gov/public/pro
file report.asp?global id=54490002
EPA. 1994. Record of Decision: Southern
California Edison Co. (Visalia Poleyard),
EPA ID: CAD980816466, OU 01, Visalia,
CA, 06/10/1994, 13 pp.
http://cfpub.epa.gov/superrods/index.cfm7fu
seaction=data.siterods&siteid=0902061
EPA Region IX. 2001.
Out Report, Southern
Visalia Pole Yard.
Preliminary Close
California Edison
Southern California Edison Company
(SCE). 2001. Visalia Steam Remedial Ac-
tion Plan, Construction Complete Report.
http://www.envirostor.dtsc.ca.gov/public/pro
file report.asp?global id=54490002
Southern California Edison Company. 2008.
Remedial Action Completion Report 2008, 9
pp.
http://www.envirostor.dtsc.ca.gov/public/pro
file report.asp?global id=54490002
32
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Southern Maryland Wood Treating Site,
Hollywood, Maryland
Technology Used: Excavation and ex situ
thermal desorption with some offsite dis-
posal, P&T
Regulatory Program: Superfund
Project Duration: Construction of the
thermal desorption units began in October
1997 and treatment was completed by Octo-
ber 2001.
Information Last Updated: 2008
Site Information: The Southern Maryland
Wood Treating facility was owned and op-
erated by the Southern Maryland Wood
Treating Company from 1965 to 1978.
Wood treating operations were conducted on
approximately 25 acres of the 94-acre prop-
erty. Wood was pressure-treated using creo-
sote and PCP, and the liquid process wastes
were disposed in six unlined lagoons. Seep-
age from the lagoons contaminated the un-
derlying soil and groundwater. Contami-
nated groundwater discharged to an onsite
pond contaminating surface water and sedi-
ments. In addition, groundwater and pond
water discharges to Old Tom's Run con-
taminated the stream sediments. Contami-
nated ground-water was not detected in pe-
rimeter monitoring wells or nearby private
drinking water wells. Storage of treated
wood onsite contaminated surface soil.
Contaminants: PAHs and benzene with
DNAPL well below the surface of the shal-
low groundwater table.
Hydrogeology: Silty and clayey sand ex-
tends to a maximum depth of 40 ft bgs at the
site. The sand is underlain by a low-
permeability, dense blue clay that is ap-
proximately 20 ft thick. DNAPL was ob-
served atop this clay layer in the area below
the lagoons. The drinking water aquifers of
the underlying Chesapeake Group are lo-
cated approximately 285 to 600 ft bgs.
Drinking water wells in the area were not
found to be contaminated.
Project Goals: The remedy required that
soil and groundwater be cleaned up to resi-
dential standards. PAHs in surface and sub-
Before: Floating Contamination on Pond,
Summer 1999
surface soil were to be cleaned up to 0.1
mg/kg (B(a)P-eq), and 1.0 mg/kg (B(a)P-
eq), respectively. The cleanup goals for
After: Restored Wetland Swale,
Spring 2001
sediment were 0.4 mg/kg PCP, 3.2 mg/kg
low molecular weight PAHs and 9.6 mg/kg
high molecular weight PAHs.
Cleanup Approach: Contaminated soil and
sediment were excavated from the site and
placed into one of two onsite thermal de-
sorbers equipped with vapor recovery sys-
tems. The lagoon area was dewatered prior
33
-------
to excavation, and the water was treated on-
site. Approximately 270,600 tons of con-
taminated soil and sediment were treated
and backfilled onsite. Highly contaminated
soil and sediments not readily treated by
thermal desorption were shipped offsite for
proper disposal.
Surface water from the onsite pond was
pumped and treated until the source soil and
sediment were cleaned up.
The site was regraded and revegetated with
a diverse mixture of wildflowers and grains
suitable for wildlife habitat.
Project Time Line:
3/14/85 First removal action (excavation of
contaminated pond sediment)
6/10/96 Site placed on the National Priori-
ties List
6/29/93 Second removal action (included
construction of an underflow dam to reduce
flow of contaminants from the pond to the
stream)
10/7/97 Construction activities began
2/00 Excavation of stream began
1/17/01 Soil and sediment treatment com-
plete
8/01 Remedial Action Completion Report
issued
2003 Two years of groundwater monitoring
complete
11/18/04 Ready for Reuse determination
issued by EPA for unrestricted use of site
4/5/05 Site deleted from NPL
Project Results: All cleanup goals were
met. Two years of groundwater monitoring
that followed soil and sediment cleanup
verified that the cleanup was a success. In
2004, a Ready for Reuse determination was
issued by EPA for unrestricted use of the
site.
Sources: U.S. EPA, 2004. Ready for Reuse
Determination Southern Maryland Wood
Treating Superfund Site, November 18.
U.S. EPA, 1999. Five-Year Review Report:
Southern Maryland Wood Treating Super-
fund Site, Hollywood, Maryland. September
30.
http://cfpub.epa.gov/fivevear/index.cfm7fus
eaction=fyrsearch.showSitePage&id=03003
05
U.S. EPA, 1995. EPA Superfund Record of
Decision: Southern Maryland Wood Treat-
ing, EPA ID: MDD980704852, OU 2, Hol-
lywood, Maryland. (EPA/ROD/R03-95/197)
September 8.
http://cfpub.epa.gov/superrods/index.cfm7fu
seaction=data.siterods&siteid=0300305
34
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Former Southern California Edison
Manufactured Gas Plant (MGP) Site.
Long Beach, California
Technologies: ISCO (ozonation), excava-
tion
Regulatory Program: Voluntary action
under DTSC's Expedited Remedial Action
Program
Project Duration: 1998 to 2003
Information Last Updated: 2003
Site Information: The Former Southern
Edison MGP site produced gas from oil and
coal from 1902 to 1913, and contaminated
soil and groundwater with PAH and TPH.
The 340-ft by 230-ft strip of land is wedged
between a freeway and the Los Angeles
River flood control channel. A dense infra-
structure of power transmission cables, un-
derground utilities, and elevated bridges
made conventional treatment difficult.
Contaminants: The initial concentrations
of soil contaminants measured at the site
were 2,484 mg/kg total PAH and 27,800
mg/kg TPH. The chemicals of potential
concern identified for soil included seven
carcinogenic PAHs, nine noncarcinogenic
PAHs, and TPH. A benzo(a)pyrene equiva-
lent (B(a)P-eq) value was calculated for
each carcinogenic PAH and summed to-
gether to estimate the total B(a)P-eq con-
centration. Prior to treatment, B(a)P-eq in
soil was slightly higher than 100 mg/kg.
Dissolved concentrations in groundwater
were as high as 912 ug/L TPH, 4.82 ug/L
benzene, 20 ug/L naphthalene, and 0.34
ug/L benzo(a)-pyrene.
Hydrogeology: The site is underlain by a
thin layer of fill overlying poorly sorted
medium- to fine-grained sand. The water
table is approximately 10 ft bgs.
Project Goals: The remedial strategy for the site
was to meet an industrial cleanup objective of
1.75 mg/kg B(a)P-eq in soil.
Cleanup Approach: ISCO through ozonation
was conducted to treat soil and groundwater. In
October 1998, 33 vertical sparging wells were
installed in the contamination plume. The
sparging wells were made of Teflon tubing for
most of their length, and stainless steel rods
wrapped with stainless steel wire mesh over the
lower 25 ft for the distribution of ozone. In addi-
tion, a single horizontal sparging well with a
135-ft screened section was installed through the
center of the plume approximately 6 ft below the
water table.
Ozone was pulsed into the wells in both the satu-
rated and vadose zones to promote chemical
oxidation and enhanced biodegradation. Ozone
generation was initiated in January 1999 and
continued until system shutdown in January
2001. Approximately 19,100 pounds of ozone
and 280,000 pounds of oxygen were generated
and injected. An SVE system was used to pre-
vent unreacted ozone from reaching the surface.
Approximately 215 yd3 of highly contaminated
soil were excavated and disposed offsite.
Project Time Line:
10/98-11/98 - In situ ozonation system con-
structed
12/98 - Pilot test conducted
1999-2003 - Ozone generation conducted
11/22/05 - Site removed from Expedited Reme-
dial Action Program
Project Results: Groundwater concentrations
were reduced below detectable levels after the
first quarter of ozone treatment. The concentra-
tion of benzo(a)pyrene was reduced to less than
the 0.2 ug/L MCL. Site-wide soil concentrations
were reduced from more than 100 mg/kg to 1.4
mg/kg of B(a)P-eq. PAH and TPH concentra-
tions in groundwater were reduced to non-detect
levels after the first injection. A thin lens of con-
taminated soil that contains up to 105 mg/kg of
B(a)P-eq remains at depth. Because of the posi-
tion of highway foundations, the lens could not
35
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be treated. DTSC will issue a Certificate of
Completion once deed restrictions are re-
corded for the property.
Sources: In-Situ Oxidative Technologies,
Inc. Case Study: Former MGP Site. South-
ern California Edison. Undated.
http: //www. insituoxidation. com/image s/C A
SE-21 %20MGP%20Site.%20California.pdf
Department of Toxic Substances Con-
trol, Edison/Long Beach II MGP (Ocean
Blvd), Envirostor.
http: //www. envirostor .dtsc. ca. gov/public
/profile report.asp?global id=19490213
Dablow, Jay, Mark Seaman, and Bruce
Marvin, IT Corporation, 2001. In Situ Ozona-
tion to Remediate Recalcitrant Organic Con-
tamination. Paper presented at the 2001 In-
ternational Containment & Remediation
Technology Conference and Exhibition, Or-
lando, FL.
http://www.containment.fsu.edU/cd/content/p
df/352.pdf
36
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Former Cowboy Cleaners Site, Broom-
field, Colorado
Technology: ISCO (potassium permanga-
nate)
Regulatory Program: Colorado Voluntary
Cleanup Program
Project Duration: 2001 to 2002
Information Last Updated: 2003
Site Information: The Former Cowboy
Cleaners site is located in Broomfield,
Colorado, near Denver. A site investigation
revealed soil and groundwater contamina-
tion. The approximate 1.5-acre plume oc-
cupied portions of five separately owned
properties and crossed beneath a street.
Small portions of the plume also flowed
beneath a retail building and a residence.
The remediation was handled under the
Colorado Voluntary Cleanup Program.
Contaminants: Groundwater at the site is
contaminated with PCE. Maximum initial
concentration of PCE was 1,900 (ig/L (sus-
pected DNAPL).
Hydrogeology: The site is underlain by a
stiff clay to silty (sometimes sandy) clay at
3 ft bgs and a sandy clay layer at 8 ft bgs.
Groundwater is at 25 bgs.
Project Goals: The State of Colorado de-
termined that the low risks to potential re-
ceptors justified a remediation of the source
areas, allowing the groundwater plume to
clean up naturally overtime.
Cleanup Approach: A system of 12 nested
injectors was installed in the source area.
Semi-permanent injectors constructed of
one-inch diameter PVC screen and riser
were installed to allow the controlled injec-
tion of permanganate reagent directly into
the contaminated area. Each injector was
installed with a sand pack to just above the
screen, and grouted to the surface.
Once the grout set, a charge of permanganate
was pressure-injected into each injector. A 10%
by weight solution of permanganate was intro-
duced into each injector, with as much volume
as each injector would take, to a maximum of
100 gallons. The injectors were then connected
to each other in ranks, and to a head tank by
PVC piping. Continuous gravity feeding to all of
the injectors was then started. Each injector was
equipped with valves to control flow, and the
system was kept in balance for about four to five
months. Up to 300 gallons per day of 1-2% solu-
tion were fed into the system during remedia-
tion.
Most of the injectors were completed above the
water table to avoid drainage of reagent directly
into groundwater without extensive soil contact.
To control PCE that was mobilized into
groundwater from the soil source area, a line of
injectors (curtain wall) was installed down
stream. These injectors were operated at very
low volumes, and controlled based on the results
of a monitoring well immediately downgradient.
Project Time Line:
09/01 - Application of permanganate
01/02 - Post-treatment monitoring
08/02 - Post-treatment monitoring complete
02/03 - NFA Determination letter issued by
Colorado Department of Public Health and En-
vironment
Project Results: One month into the remedia-
tion process, the PCE concentration had dropped
to 926 (ig/L and decreased further to 48 (ig/L in
about a year. Downgradient PCE concentrations
decreased from 40 ug/L to 15 ug/L within a
year. Quarterly monitoring showed PCE concen-
trations in source-area groundwater were re-
duced by 99% and downgradient concentrations
were less than the Colorado drinking water
MCL. In February 2003, the State of Colorado
issued a NFA Determination Approval, stating
that the property could be used for commercial
purposes, and did not pose an unacceptable risk
to human health and the environment.
37
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Sources: Colorado Department of Public Viellenave, J.H., J.P. Lauer, and J.V. Fontana.
Health and Environment. 2003. NFA Ap- 2002. Using Risk Based Cleanup Goals for
proval. James Viellenave. December 16, ISCO of PCE in Vadose Zone Soils Under a
2003. Voluntary Cleanup Program. Paper presented at
IPEC 2002.
E-mail to Raji Ganguli, Tetra Tech EM, http://ipec.utulsa.edu/Conf2002/viellenave_lauer
Inc. providing information on the Former fontana 66.pdf
Cowboy Cleaners Site in Broomfield, Colo-
rado.
38
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Dry Clean USA No. 11502, Orlando, Flo-
rida
Technologies: ISCO (hydrogen peroxide),
P&T, SVE
Regulatory Program: Florida Department
of Environmental Protection's Dry cleaning
Program
Project Duration: April 1999 to October
2005
Information Last Updated: 2008
Site Information: The Former Dry Clean
USA operated in a shopping plaza in Or-
lando, Florida, from 1988 to 1998. Investi-
gations indicated that PCE was released to
the soil beneath the floor slab of the facility
in the area where the drycleaning machine
was located. Releases also occurred from the
sanitary sewer line.
SVE and P&T systems were run between
April 1999 to November 2002 with only 9.8
Ibs of VOCs recovered through SVE and a
negligible amount of VOCs recovered
through P&T.
Contaminants: PCE was detected at con-
centrations of up to 27,300 (ig/L in ground-
water and 3.9 mg/kg in soil. The contami-
nant plume extends to about 68-ft bgs and is
800-ft long and 300-ft wide.
Hydrogeology: The site is underlain by a
slightly silty, fine- to medium-grained sand
to a depth of 47 ft bgs. This unit is in turn
underlain by a 6-ft-thick, slightly sandy clay
followed by a 20-ft-thick, fine- to medium-
grained sand that is interbedded with clayey
sand. A 4-ft-thick fine to coarse sand with
shell fragments overlays a hard, phosphatic,
limestone bedrock that occurs 93 to 94 ft
bgs. The depth to groundwater is 8 to 10 ft
bgs.
Project Goals: The goal was to treat PCE to
the Florida MCL of 3 (ig/L for groundwater
and 30 (ig/kg (leachability) for soil.
Cleanup Approach: SVE for soil contami-
nation and P&T for groundwater were suc-
cessful in reducing groundwater contamina-
tion levels to <10 (ig/L. Rebound did occur
near the source area, so a 1% hydrogen per-
oxide solution was used as a polishing step.
Project Time Line:
4/99 - SVE and P&T systems start
12/01/00-SVE turned off
1/17/01 - P&T system shut down
2/26/01 - P&T system restarted because of
rebound
11/02 - P&T system turned off
10/04/05 - 10/05/05 - Peroxide injections
2/07 - Site Rehabilitation Completion Order
signed
Project Results: One year of post oxidation
groundwater monitoring showed concentra-
tions of PCE ranging from non-detect to 3
(ig/L. The Site Rehabilitation Completion
Order was signed February 16, 2007, and all
wells were abandoned.
Sources: State Coalition for Remediation of
Dry cleaners profile. Dry Clean USA
#11502. June 2008.
http://www.drvcleancoalition.org/profiles/di
splay.cfm?id=24
Personal communication with William Linn,
May 8, 2007.
39
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Naval Submarine Base Kings Bay Site 11,
Camden County, Georgia
Technologies: P&T, ISCO (Fenton's re-
agent), biostimulation, MNA
Regulatory Program: RCRA Corrective
Action
Project Duration: 1993 to present
Project Last Updated: 2004
Site Information: Site 11, the former Cam-
den County Landfill, is located on Kings
Bay Naval Submarine Base. The 25-acre site
was used for municipal waste disposal from
1973 until 1980. Trenches 2-3 m deep were
excavated, filled with trash, and covered.
Contaminants: Chlorinated solvents that
were disposed in the landfill are the source
of a groundwater contaminant plume esti-
mated to be 700-ft long, 200-ft wide, and
30- to 40-ft deep. Measured concentrations
of the contaminants of concern ranged as
high as 8,500 ug/L PCE, 550 ug/L TCE,
1,300 ug/L cis-DCE, and 4,500 ug/L vinyl
chloride. Profiling with direct push equip-
ment identified two localized DNAPL
source areas.
Hydrogeology: Site 11 is underlain by mar-
ginal marine sediments of barrier island and
back-barrier lagoon origin. The most perme-
able sand underlying the site is between 32
and 42 ft bgs. This permeable zone is under-
lain and overlain by a finer-grained sand and
clay unit, which is characterized by lower
hydraulic conductivity. A layer of organic-
rich sand overlies the aquifer. As precipita-
tion infiltrates this organic layer, it becomes
anaerobic, thereby forming a naturally oc-
curring anaerobic biodegradation system.
Groundwater is encountered at about 6 ft
bgs. An important feature of the groundwa-
ter chemistry is that the sulfate-reducing
conditions predominate near the landfill
while iron-reducing conditions exist further
downgradient. The sulfate reducing condi-
tions favor degradation of PCE, TCE, and
Organic rich layer at outcrop
Courtesy USGS
DCE, while the iron-reducing conditions
favor degradation of vinyl chloride.
Project Goals: The goal of remedial action
at the landfill was to reduce contaminant
concentrations in the groundwater plume to
levels below the MCLs established by the
Georgia Department of Natural Resources
(GDNR).
Cleanup Approach: P&T was chosen to
contain and treat the groundwater plume
with UV oxidation. The P&T system, which
was installed in 1993, was expected to oper-
ate for at least fifty years to meet GDNR's
cleanup goals. This projection was based on
Approximate Extent
ofpre-1998
Contaminant Source
Area
Vinyl Chloride Plume before Cleanup
Courtesy: USGS
40
-------
Approximate Exlenl
of the Fenton's
Reagent Treatment
Vinyl Chloride Plume after Cleanup
(January 2004)
Courtesy: USGS
the high concentrations of chlorinated com-
pounds at the site and their low solubility,
and on P&T performance data.
The July 1998 corrective action plan called
for containment of the plume at the Navy
property line. Containment would be facili-
tated with extraction wells at the perimeter
of the installation. The extraction wells
would operate until contaminant concentra-
tions were low enough for MNA to be effec-
tive on any off site contamination.
ISCO was selected to treat total VOCs in the
source area to below 100 ug/L. Since it was
not considered possible to achieve zero lev-
els of contamination in the source area, the
corrective action plan relied on the reason-
able expectation that after removal of the
source material, the downgradient plume
would attenuate. The USGS used natural
attenuation software to calculate the levels
of residual contamination in the source area
that would allow downgradient attenuation
to meet the remediation goals. These calcu-
lations provided rational performance stan-
dards for the source removal contractors.
The treatment area consisted of an estimated
3,000 tons of contaminated soil and 80,000
gallons of contaminated groundwater.
In November 1998, two extraction wells and
six process monitoring wells were installed
along with 23 specially designed injection
wells that were placed in and around the
source area. The monitoring wells were
sampled twice daily and analyzed for pH,
specific conductance, alkalinity, iron, sul-
fate, sulfide, dissolved hydrogen, and dis-
solved oxygen as well as any change in con-
taminant concentrations.
Injection Well
Courtesy U.S. Navy
Fenton's reagent containing 50% hydrogen
peroxide was injected twice. The first injec-
tion focused on the central part of the con-
taminant plume, while the second focused
on the downgradient areas that were not
treated during the first injection. Following
the second injection, during which 21 new
injectors were added, elevated contaminant
concentrations (1,700 ug/L) were detected
near one injector indicating the presence of a
previously unidentified source area. Thus,
two more injections were conducted with the
final injection in November 2001.
Since adding Fenton's reagent to an aquifer
can change both the geochemistry and the
microbial population, monitoring was per-
formed. Measurements in one monitoring
well showed an increase in dissolved oxygen
from non-detect before injection to over 7
mg/L after injection. Also, microbial activity
decreased after each injection. Dissolved
hydrogen concentrations indicated that the
injection of the ferrous iron activator had
41
-------
Courtesy: U.S. Navy
shifted the microbial activity from sulfate-
and iron-reducing to a more purely iron-
reducing environment. To reverse this trend,
biostimulation was conducted by injecting a
solution of emulsified vegetable oil (35%
soybean oil with lecithin and 65% water)
into the aquifer after the third and fourth
injections to return the subsurface to an an-
aerobic environment and restore some of the
sulfate-reducing activity that increases PCE
and TCE degradation. Microbial activity
generally rebounded within a few months of
each Fenton's reagent injection.
In all, about 48,000 gallons of 50% hydro-
gen peroxide solution and a similar volume
of ferrous sulfate catalyst were injected into
the aquifer—principally in the more perme-
able zone between 32 and 42 ft bgs. In addi-
tion, about 25,000 gallons of the emulsified
soybean oil solution were injected following
the third and fourth injections of Fenton's
reagent application.
Project Time Line:
1993—Began P&T containment system
November 1998 to February
1999-Performed first ISCO treatment
June 1999 to July 1999-Performed second
ISCO treatment
Fall 1999-Shut down P&T system
July 1999 to January 2001-Performed third
ISCO treatment
November 2001—Performed fourth and final
ISCO treatment
Project Results: Levels of total chlorinated
hydrocarbons in the most contaminated area
decreased from nearly 200,000 ug/L in 1999
to 120 ug/L in 2002. As of 2004, they
ranged from <1 to 13.9 ug/L. The plume
size shrank by about 70%.
The USGS modeling, supported by field
data, indicated that when the concentrations
of total chlorinated hydrocarbons in
groundwater were lowered to about 100
ug/L, MNA would complete cleanup of the
plume in about three years. As of May 2003,
no exceedances of MCLs occurred in any of
the offsite monitoring wells, and many of
the onsite monitoring wells had no measur-
able levels of contaminants. As a result, the
P&T system was shut off two months after
the second ISCO treatment, and MNA has
been implemented as the final corrective
action for the landfill. There was no need for
further treatment with UV oxidation. Shut-
ting down the P&T system slowed the trans-
port rate of contaminants downgradient,
which increased the effectiveness of the bio-
degradation process.
The estimated cost of the remedial action
from 1991 to 1997 was $9.8 million. The
estimated cost for the ISCO and biostimula-
tion is approximately $5 million. This repre-
sents a $9 million savings over the estimated
$15 million that the P&T system would have
cost.
42
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Sources: Chapelle, F.H. and P.M. Bradley.
1999. Selecting remediation goals by assess-
ing the natural attenuation capacity of
ground-water systems. Proceedings of the
Technical Meeting Charleston, South Caro-
lina. March 8-12, 1999, Volume 3 of 3 Sub-
surface Contamination From Point Sources,
Water-Resources Investigations Report 99-
4018C. U.S. Geological Survey
http://toxics.usgs.gov/pubs/wri99-
4018/Volume3/kevnote/3102 Chapelle/inde
x.html
Chapelle, F.H., P.M. Bradley, and C.C. Ca-
sey. 2005. Behavior of a chlorinated ethene
plume following source-area treatment with
Fenton's reagent. Ground Water Monitoring
& Remediation, Vol. 25 No 2, p 131-141,
Spring
Chapelle, F.H. and M. Singletary. 2006.
Combining Source Area Treatment with
Monitored Natural Attenuation, NSB Kings
Bay. PowerPoint presentation from Federal
Remediation Roundtable meeting
http://www.frtr.gov/pdf/meetings/may07/cha
pelle presentation.pdf
FRTR. 2000. In situ Chemical Oxidation
Using Fenton's Reagent at Naval Submarine
Base Kings Bay, Site 11, Camden County,
Georgia. Federal Remediation Roundtable
http://costperformance.Org/pdf/KingsBav.P
DF
Spinner, J. 2004. Groundwater Almost
Clean. The Periscope April 29, 2004
http://www.kingsbavperiscope.eom/stories/0
42904/kin groundwaterOOl .shttnl
NAVFAC SOUTHDIV. Undated. Site 11,
Old Camden County Landfill, Remedial Ac-
tion Operation, Summary Report: Remedial
Action Operation Optimization. U.S. Navy,
8pp
http://costperformance.org/pdf/KingsBav C
hemOx.pdf
43
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Former Sta-Lube Site, Rancho Domin-
guez, California
Technologies: SVE, P&T, large-diameter
auger excavation with offsite disposal, ISCO
(catalyzed hydrogen peroxide to activate
sodium persulfate)
Regulatory Program: California Regional
Water Quality Control Board (RWQCB),
Los Angeles Region
Project Duration: June 2005 to June 2008
Information Last Updated: 2008
Site Information: The former Sta-Lube site
occupies 2.8 acres. From 1968-1986, Sta-
Lube, Inc. manufactured paint, varnish re-
mover, and fuel additives and blended and
packaged hand cleaners, greases, and petro-
leum-based lubricants.
Contaminants: Past industrial activities at
the site used a variety of chemicals, includ-
ing petroleum hydrocarbon derivatives and
solvents such as methylene chloride. Site
investigations indicated that soil and
groundwater were contaminated with vola-
tile organic compounds; methylene chloride
was the main contaminant of concern. A
past release of methylene chloride from a
leaking UST caused extensive contamina-
tion. In 1995, the dissolved plume measured
200-feet long by 80-feet wide. By 2005, the
size of the plume had been reduced to 80-
feet long by 30-ft wide, most of which was
under the building. The highest concentra-
tion of methylene chloride detected in the
groundwater was 2,600,000 ug/L, well ex-
ceeding the 1% solubility limit of 200,000
ug/L.
A membrane interface probe (MIP) survey
later indicated that methylene chloride
DNAPL was trapped in sandy stringers
within the clayey soil underlying the build-
ing.
Hydrogeology: The site is located within
the Central Groundwater Basin, which is
part of the Los Angeles Coastal Plain. The
near-surface sediments at the site are part of
the Bellflower Aquiclude, a portion of the
Recent Alluvium primarily comprising silts
and clays. These fine-grained sediments are
found beneath the Sta-Lube site to a depth of
approximately 45 feet bgs. The depth to the
water table is approximately 40 feet bgs.
Using the MIP, an 8-foot thick clay zone
with thin sand stringers (4-8 inches) was
delineated between 40 to 48 feet bgs, while
coarse sand is found from 48 feet to over
130 feet bgs.
The groundwater beneath the Sta-Lube site
correlates regionally with the Gaspur Aqui-
fer. The bottom of the Gaspur Aquifer is
approximately 140 feet beneath the Sta-
Lube site. Beneath this aquifer, several clay-
lens aquitards limit vertical migration of the
contaminant to the Silverado and Sunnyside
Aquifers, which are at depths of approxi-
mately 450 to 700 feet bgs. These deeper
aquifers are considered high-quality drink-
ing water aquifers.
The California Water Company has indi-
cated that the closest active drinking water
well is located 1,750 feet to the southwest of
the Sta-Lube site. The well screen is set at
301 to 650 feet bgs and penetrates the Sil-
verado and Sunnyside Aquifers. The
groundwater flow direction in the upper
saturated zone is towards the southwest
placing the well downgradient of the site.
However, the Sta-Lube plume is located at
40 to 60 feet bgs, which is the upper 20 feet
of the saturated zone beneath the site.
Project Goals: After 6 years of SVE, P&T,
and a large-diameter auger excavation, the
overall goal of implementing ISCO was to
quickly attain closure of the site from the
RWQCB. The cleanup goal was to attain
concentrations less than 50 ug/L of methyl-
ene chloride in groundwater.
Cleanup Approach: A P&T system was
operated at the Sta-Lube site starting in 1997
to treat the dissolved-phase plume. The P&T
system operated until 2003. An SVE system
44
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supplemented with hot air injection was op-
erated at the site starting in May 2000 and
continuing until October 2001. Concentra-
tions of methylene chloride in groundwater
from the pumping wells were below 100
ug/L, and the soil and groundwater were
close to attaining closure from the RWQCB.
However, when the systems were turned off,
the concentrations of methylene chloride
rebounded significantly suggesting presence
ofDNAPL.
A supplemental site investigation conducted
using MIP revealed DNAPL source zones in
sandy stringers trapped within clayey zones
at depths of 40 to 48 feet. To remove the
DNAPL, these source zones were excavated
to a depth of 48 feet using large-diameter
augers. The excavated soil, which was con-
taminated (266 cubic yards), was staged and
disposed of offsite. Despite these efforts,
groundwater contamination levels still re-
mained high (Table 1). Further investigation
revealed methylene chloride had migrated
into the clayey soil beneath the building and
was slowly seeping out and contaminating
the groundwater.
Table 1. Groundwater Contaminant
Concentrations Measured June 14, 2004
Contaminant
Acetone
Benzene
Toluene
Bromochloromethane
1,1 -DCA
1,1 -DCE
Trans-l,2-DCE
Bromoform
Dibromochloromethane
Chloroform
Methylene Chloride
1,1,2,2-TCA
Concentration
Range (jig/L)
ND - 220
ND - 6.7
ND-34
ND-110
ND-27
ND-89
ND-73
ND- 16
ND- 11
ND-88
ND - 18,000
ND-25
ND = non-detect
On December 15, 2004, the RWQCB ap-
proved ISCO using catalyzed hydrogen per-
oxide activation of sodium persulfate
(Kloziir®) for groundwater remediation.
Activated sodium persulfate is a strong oxi-
dant that creates sulfate radicals, which are
effective in treating dissolved recalcitrant
contaminants. The catalyzed hydrogen per-
oxide (a Fenton's type reaction) attacks con-
taminants directly with the hydroxyl radicals
that are produced. The Fenton's reaction is a
highly exothermic reaction that helps to strip
the sorbed contaminants from the soil and
convert them to the dissolved phase.
A total of 23 application wells were installed
at the site-16 inside and 7 outside the build-
ing (Figure l)-with an estimated radius of
influence of 8 to 12 feet. The target ground-
water remediation zone was 40 to 48 feet
below grade surface.
Figure 1. ISCO Application Wells
Courtesy: Gary Cronk
Approximately 7,700 gallons of 22% so-
dium persulfate solution was injected over
the course of six days. This was followed by
an injection of 12,044 gallons of 17.5% hy-
drogen peroxide for 14 days to activate the
persulfate. Downhole thermocouples moni-
tored the temperature underground to ensure
a temperature of 120 to 160°F for optimum
generation of hydroxyl radicals with mini-
mal decomposition of the hydrogen perox-
ide. Logistical challenges included the use
of angled wells to minimize disruption of
business operations in the building and
safely performing injections inside an active
facility. The reaction of catalyzed peroxide
produces hydroxyl radicals, heat, and oxy-
gen which tend to force treated groundwater
and vapor up to the ground surface via con-
45
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duits (e.g., soil crevices, abandoned borings,
utility lines, etc.). Therefore, the flow of the
injectants had to be optimized to control the
reaction.
Project Time Line:
1997-2003—Operation of pump and treat
system to treat dissolved-phase plume.
2000-2001-Operation of SVE and hot air
injection to treat the vadose zone soils.
2003—Large-diameter auger excavation of
DNAPL source area and disposal of con-
taminated soil offsite. Subsequent discovery
of additional DNAPL beneath the building.
December 15, 2004- RWQCB approves use
of ISCO to treat contaminated soil beneath
building and the groundwater contaminant
plume emanating from it.
June 2005—Persulfate and peroxide injected
into treatment area.
November 2005—Cleanup goal of 50 ug/L
methylene chloride is reached.
2005-2008—Quarterly monitoring
June 2008-California RWQCB grants final
closure of site.
Project Results: Monitoring results indi-
cated that ISCO reduced methylene chloride
levels by 94% to 97% within 4 months fol-
lowing treatment and below the 50 ug/L
cleanup goal within 5 months (Figure 2).
The most significant reduction observed was
a decrease from 15,000 to 18 ug/L in one
well. Quarterly monitoring followed and in
June 2008, the site obtained final closure
from the California RWQCB.
100,000 i
10,000
ll.OOO
0
1 100
5 10
<;
^15,000
^/3,200
/ ^V11° 110 140
/ ^NJf " "
*'^WV^V
-^MW-1A
— MW-9A
MW-11
MW-12
flT^IO
Figure 2. Methylene Chloride Concentra-
tions in Groundwater During ISCO
Courtesy: Gary Cronk
Sources: Personal communication with
Gary Cronk, September 18, 2007.
Cronk, Gary. 2006. Optimization of a
chemical oxidation treatment train process
for groundwater remediation" Presentation
at the Battelle 5th International Conference
on Remediation of Chlorinated and Recalci-
trant Compounds. May 25, 2006. Monterey,
CA.
http: ll\ agconsultinggroup.com/uploads/Full
Paper - Cronk Battelle 2006.pdf
California Regional Water Quality Control
Board, Los Angeles Region. Letter from
Executive Officer, Jonathan S. Bishop, to
Judi Proetel of Sta-Lube, Inc.
FMC Environmental Solutions. Klozur™
Resource Center. Project Description In-Situ
Chemical Oxidation, Activated Persulfate
Treatment of Methylene Chloride Chemical
Plant in Los Angeles, CA.
http://www.envsolutions.fmc.com/Portals/
fao/Content/Docs/Remediation%20of%20M
ethvlene%20Chloride%20Plume%
20Using%20H2O2%20Catalvzed%20Persul
fate MECX.pdf
46
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Pasley Solvents and Chemicals, Inc.,
Hempstead, New York
Technologies: SVE, air sparging
Regulatory Program: U.S. EPA Superfund
Project Duration: November 1997 to Au-
gust 2003
Information Last Updated: 2007
Site Information: Pasley Solvents and
Chemicals, Inc., is a former tank farm that
stored oils, solvents, and other chemicals in
above-ground tanks prior to transferring
them to 5 5-gallon drums for delivery to cus-
tomers. The property is about 75 ft wide and
275 ft long. Poor housekeeping and spills
have contaminated soil and groundwater
with VOCs and semivolatile organic com-
pounds (SVOCs).
Contaminants: The contaminants of con-
cern at the site were 1,1-DCA, 1,1-DCE,
trans-DCE, chloroform, TCE, toluene,
chlorobenzene, ethylbenzene, and xylenes.
The highest concentration of total VOCs
(mostly PCE and trans-\,2-DCE) and
SVOCs detected in surface soil was 603
mg/kg and 204 mg/kg, respectively. The
maximum concentration of total VOCs
measured in groundwater was 37 mg/L
(mostly trans-].,2-DCE). The highest TCE
concentration was 320 ug/L, well higher
than the 5 ug/L MCL. The 60-ft by 400-ft
groundwater contaminant plume extended
beyond the site boundary.
Hydrogeology: The site is underlain by 60
ft of glacial outwash deposits consisting of
unconsolidated sand and gravel. These de-
posits are underlain by the Magothy Aqui-
fer, a 400- to 500-ft thick formation consist-
ing of fine sand with discontinuous layers of
silt and clay. Public water supply wells for
the nearby Town of Hempstead draw water
from the Magothy Aquifer.
Project Goals: The project goals were to
clean up the site to residential risk levels and
MCLs.
Cleanup Approach: Chemical source areas
in the vadose zone were treated with SVE,
and the groundwater plume was treated us-
ing air sparging wells to encourage aerobic
bioremediation and volatilization.
For the onsite contamination, 19 2-inch PVC
air sparging wells screened 50 to 52 ft bgs;
eight shallow 2-inch PVC SVE wells,
screened 5 to 10 ft bgs; eight 4-inch PVC
SVE wells, screened 15 to 20 ft bgs; and
five monitoring well clusters were installed.
To treat the offsite plume, 15 2-inch PVC air
sparging wells, screened 50 to 52 ft bgs; five
2-inch PVC SVE wells, screened 15 to 20 ft
bgs; and six monitoring-well clusters were
installed. Collected vapors were treated with
activated carbon. In accordance with the
Consent Decree and O&M Manual, the
O&M period was to be performed for a
minimum of five years followed by post-
remediation monitoring.
Project Time Line:
6/97 - Construction of the remedy begins
10/97 - Remedy construction completed
11/97 - Remedy becomes operational
10/02 - SVE/AS system shut down to test
for rebound
July 2000 and April 2003 - Confirmation
soil sampling
2004 - Remediation equipment removed
from site
2004-2006 - Semi-annual groundwater
monitoring
2006 - NFA discontinue groundwater moni-
toring
Project Results: Soil confirmation sampling
indicated that residential cleanup values (all
under 1 mg/kg for the contaminants of con-
cern) were met. Concentrations of total
VOCs in monitoring wells also met ground-
47
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water treatment goals. Within two years of
air sparging operation, concentrations of
total VOCs in onsite monitoring wells
ranged from non-detect to 4 (ig/L, which
was down from original concentrations
ranging as high as 7,496 ug/L. After five
years, concentrations in offsite monitoring
wells were all below MCLs for 12 straight
quarters.
Sources: Personal communication with
Sherrel Henry, U.S. EPA Region 2, April 2,
2007.
U.S. EPA. 1992. Record of Decision: Pasley
Solvents & Chemicals, Inc. EPA ID:
NYD991292004, OU 01 Hempstead, NY.
http://www.epa.gov/superfund/sites/rods/full
text/10292171.pdf
U.S. EPA. 2004. Five-Year Review Report
Pasley Solvents and Chemical Site Town of
Hempstead Nassau County, New York.
http://www.epa.gov/superfund/sites/fivevear
/F04-02026.pdf
48
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Appendix B
Suspected DNAPL Thresholds Based
On Solubility Relative to One Percent of
Aqueous Solubility
49
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Suspected DNAPL Thresholds Based on Solubility
Relative to 1% of Aqueous Solubility
Chlorinated Solvent (CAS Number)
PCE (127-18-4)
TCE (79-0 1-6)
cw-DCE( 156-59-2)
frans-l,2-DCE (156-60-5)
,1-DCE (75-35-4)
,1,1-TCA (71-55-6)
,1,2-TCA (79-00-5)
,2-DCA (107-06-2)
,1-DCA (75-34-3)
Carbon Disulfide(75-15-0)
Carbon Tetrachloride (56-23-5)
Chlorobenzene (108-90-7)
Chloroform (67-66-3)
Hexachlorobutadiene (87-68-3)
Methylene Chloride (75-09-2)
1,1,2-Trichlorofluoromethane (75-69-4)
1 , 1 ,2-Trichlorotrifluorethane (76-13-1)
Aqueous Solubility
Gig/L@20°C)
150,000
1,100,000
3,500,000
600,000
400,000
1,360,000
4,500,000
8,690,000
5,500,000
2,100,000
800,000
500,000
8,000,000
2,550
20,000,000
1,100,000
200,000
1% of Aqueous Solubility
Gig/L@20°C)
1,500
11,000
35,000
6,000
4,000
13,600
45,000
86,900
55,000
21,000
8,000
5,000
80,000
25
200,000
11,000
2,000
Notes:
1. The source for all Aqueous Solubility and 1 Percent Rule except 1,2 cis DCE: Cohen, R.
and J. Mercer. 1993. DNAPL Site Evaluation, EPA 600/R-93/022.
http://www.cluin.org/download/contaminantfocus/dnapl/600r93022.pdf
2. Source for 1,2-cis DCE solubility datum: Howard, P. (ed.).1989. Handbook of Environ-
mental Fate and Exposure Data for Organic Chemicals. Lewis Publishers.
3. DCA (dichloroethane), DCE (dichloroethene) PCE (tetrachloroethene), TCA (trichloro-
ethane), TCE (trichloroethene)
If the chemicals are part of a mixture, then their solubility will be less than the solubility of the
pure substances. The effective solubility of each component can be estimated using Raoult's
Law and is equal to the mole fraction of the component in the NAPL times its pure form solubil-
ity (Cohen and Mercer 1993).
50
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Appendix C
Acronyms and Abbreviations
51
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(ig/L micrograms per liter
bgs below ground surface
B(a)P benzo(a)pyrene
B(a)P-eq benzo(a)pyrene equivalent
CEAM Conceptual Environmental Assessment Model
COC certificate of completion
DCE dichloroethene
DNAPL dense non-aqueous phase liquid
DTSC Department of Toxic Substances Control
EPA U.S. Environmental Protection Agency
ERH electrical resistive heating
ft foot or feet
ft2 square foot or feet
ft3 cubic foot or feet
gpm gallons per minute
GW groundwater
HRC® Hydrogen Release Compound
1C institutional controls
IDEM Indiana Department of Environmental Management
IEPA Illinois Environmental Protection Agency
ISTD in situ thermal desorption
L liter
MADEP Massachusetts Department of Environmental Protection
MC methylene chloride
MCL maximum contaminant level (EPA)
mg/kg milligrams per kilogram
mg/L milligrams per liter
MGP manufactured gas plant
MNA monitored natural attenuation
ND non-detectable
NFA no further action
NFR no further remediation
NPL National Priorities List
P&T pump and treat
PAH polycyclic aromatic hydrocarbon
PCE tetrachloroethene
REEL risk-based exposure level
RCRA Resource Conservation and Recovery Act
SCE Southern California Edison
scfm standard cubic feet per minute
SVE soil vapor extraction
SVOC semivolatile organic compound
TACO tiered approach to correction action objectives
1,1,1-TCA trichloroethane
TCE trichloroethene
TCEQ Texas Commission on Environmental Quality
TPH total petroleum hydrocarbons
TRRP Texas Risk Reduction Program
VC vinyl chloride
VOC volatile organic compound
yd3 cubic yard
52
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