Dense Nonaqueous Phase Liquids (DNAPLs)

Combined Remedies

Examples for the Class of Halogenated Alkenes

General Information

Coupling Surfactants/Cosolvents with Oxidants for Enhanced DNAPL Removal: A Review
Dugan, P.J., R.L. Siegrist, and M.L. Crimi.
Remediation Journal, Vol 20 No 3, p 27-49, 2010

This paper provides a critical review of peer-reviewed scientific literature, non-reviewed professional journals, and conference proceedings that discuss the use of surfactants/cosolvents and oxidants, either concurrently or sequentially, for DNAPL mass removal. Longer abstract Additional information is available in a slide presentation.

Efforts to Improve Coupled In Situ Chemical Oxidation with Bioremediation: A Review of Optimization Strategies
Sutton, N.B., J.T.C. Grotenhuis, A.A.M. Langenhoff, and H.H.M. Rijnaarts.
Journal of Soils and Sediments 11(1):129-140(2011)

The purpose of this review is to integrate recent results on coupled ISCO and bioremediation with the goal of identifying parameters necessary to an optimized biphasic treatment and areas that require additional focus.

Halogenated Alkene Mixtures

Activated Peroxygens for Remediation of Contaminated Soil and Groundwater
Bennedsen, Lars Ronn, Ph.D. thesis, Aalborg University Esbjerg, Denmark. ISBN: 978-87-90033-78-1, 99 pp, 2011

This thesis deals with several aspects of the use of modified Fenton's reagent (MFR) and activated sodium persulfate (ASP) for remediation of contaminated soil and groundwater at the largest contaminated site in Denmark, Kaergard Plantation, one of the most difficult remediation challenges in Scandinavia. Pharmaceutical wastewater, legally disposed of on the site the between 1956 and 1973, contained inorganic and organic acid salts, sulfonamides, barbiturates, aniline, pyridine, phenols, benzene, toluene, lithium, mercury, and cyanide. Chlorinated solvents are also found in the groundwater. This thesis describes the use of MFR at pilot scale in Kærgaerd Plantation, with a discussion of the results for destruction of PCE, TCE, toluene, and benzene. Subsequent addition of a buffer (carbonate/hydrogen carbonate) and electron donor (Newman zone, emulsified soybean oil) rapidly converted the subsurface environment to conditions favorable for biological remediation with enhanced reductive dechlorination. Signs of reductive dechlorination were observed shortly after addition of electron donor and subsequent bioaugmentation.

Clarian Corporation (formerly Sandoz Chemicals) (RCRA)
U.S. EPA Region 2, Mar 2005
Contact: Shane Nelson, 212- 637-3130, nelson.shane@epa.gov

The EI determination states that this 13.5-acre facility was used to mine sand and gravel to groundwater depth (~30 feet bgs) and later for chemical manufacturing of textile/paper softeners, optical brighteners, and dyes. Operations included an UST, now closed. More recently, the site supported a leather/textile laboratory. Remedial investigations have been underway since 1989 to address surface/subsurface soil and groundwater contaminants identified in 1992 (Cr, DCB, chlorobenzene, MTBE, PCE, TCE, methylene chloride). Excavation and off-site soil disposal was conducted, and NFAs were proposed for selected AECs. Air sparging/soil vapor extraction has operated since 1995 to address soil and groundwater at the former UST farm area, a ventilation trench, and a former lime pit. The 1994 phase II investigations indicated DNAPL in the area of an unconsolidated aquifer, and DNAPL was later confirmed in apparently connected and fractured Passaic bedrock. An area approximately 270 feet by 240 feet within the saturated zone soil and shallow unconsolidated aquifer, including off-site locations, is suspected to be impacted by DNAPL. An undated Clarian Corporation fact sheet indicates chemical oxidation was/is considered.

Demonstration of Resin Adsorption Technology for Treatment of VOCs in Groundwater
G. Prior, W. Lowe, J.P. Gross, and C. Murphy.
WEFTEC 2004: Water Environment Federation Annual Conference and Exposition, 2 - 6 October 2004, New Orleans, LA. Technical Paper #0403, 22 pp, 2004

PCE, TCE, and their breakdown products are the primary contaminants of concern in the East Canal Creek Area plume at Aberdeen Proving Ground. The Record of Decision specified precipitation and filtration to remove iron and manganese, followed by synthetic resin adsorption with on-site steam regeneration to remove VOCs. A pilot test was conducted to confirm the effectiveness of the resin to remove VOCs to levels suitable for potable water beneficial reuse, to define the capacity of the medium after multiple exhaustion and regeneration cycles, and to provide data for the design of the groundwater treatment plant. The pilot treatment system consisted of pretreatment equipment to remove iron and manganese from the ground water, followed by two columns, in series, of Ambersorb® 563 media operating in lead-lag mode to increase the treatment run length. After construction of the pilot plant, eight column exhaustion and nine regeneration cycles were completed during the testing program. The results demonstrate that with proper control of the service cycle and regeneration of the media, this treatment train will produce water containing no detectable VOCs for extended periods. The facility has been in full-scale operation since April 2003. In the first 11 months of full-scale operation, about 71 million gallons of contaminated groundwater were treated with an average total VOC removal efficiency of 96%.

Electrical Resistive Heating (ERH) and Biosparging at the ICN Pharmaceuticals Incorporated Site, Portland, Oregon
Federal Remediation Technologies Roundtable Cost & Performance Database, 2007

After removal of the building and associated structures from the site in 1993 and 1994, site investigations found TCE, DCE, VC, benzene, and toluene in the ground water in the vicinity of a former dry well. Concentrations of chlorinated organics >1% of their solubility suggested the presence of DNAPL. ERH was implemented in conjunction with SVE at the site to treat the DNAPL source and dissolved-phase organics in the ground water. Following cessation of ERH treatment in December 2001, residual concentrations remained above Oregon's MCLs (i.e., 5 µg/L TCE, 70 µg/L DCE, 2 µg/L VC, and 5,600 µg/L toluene). Biosparging was conducted intermittently between December 2002 and October 2003 to address this remaining contamination. Results from April 2005 indicated that only a few wells remained above MCLs and concentrations generally were declining. Ground-water monitoring continues in accordance with the long-term monitoring plan approved by the Oregon DEQ.

Gold Mills Incorporated (RCRA): Fact Sheet
and
Gold Mills Inc. Documentation of Environmental Indicator Determination
U.S. EPA Region 3, Jan 2007
Contact: Victoria Ioff, 215-814-3415, ioff.vickie@epa.gov

The 33-acre site on the banks of Schuylkill Creek was used for tanneries and later for synthetic fabric dying and finishing. The site is affected by TCA, TCE, PCE, Pb, and Cd. Contaminated soil (63,000 tons) was excavated in 1988, and an additional 900 tons were removed in 1998. A portion of the facility, including an area of the main plant building, was capped with asphalt. A 2,000,000 gal/day P&T with activated carbon system at 3 on-site wells has been used since 1992, and 2006 data show significant PCE reduction. A full-scale SVE system began operating in 2003, to be followed by MNA. Bi-monthly monitoring indicates the plume is not migrating.

In Situ Chemical Oxidation, Soil Vapor Extraction, and In Situ Bio-Stimulation at Hanner's Dry Cleaners, Pompano Beach, Florida
Federal Remediation Technologies Roundtable Cost & Performance Database, 2007

A site assessment showed contamination in both soil and groundwater at the facility with a plume of halogenated organic constituents extending beyond the boundaries of the site. PCE in soil was detected at concentrations as high as 37,200 µg/kg, with TCE up to 3,320 µg/kg. Concentrations of total chlorinated ethenes as high as 225,589 µg/L were detected in the core of the groundwater plume. Concentrations of PCE in this area also exceeded 20% of solubility (200,000 µg/L), indicating the likely presence of residual DNAPL. Initial site remediation consisted of limited excavation of accessible contaminated soil, with SVE of the remaining soils from April 2001 to May 2002, when a determination was made that no further action was required for the site's soil. ISCO was implemented to reduce ground-water contamination in the core plume area. After three full-scale ISCO injection events between May 2001 and April 2002, the overall size of the ground-water plume had decreased from 36 acres to 0.2 acre, and concentrations of PCE and TCE were lower in the source area by an order of magnitude. In June 2004, additional soil excavation was conducted in the source area to remove DNAPL contamination, and an in situ biostimulation pilot test was conducted in the excavated area. Four full-scale lactate injection events were conducted between February 2006 and April 2007. Subsequent monitoring indicated that all concentrations of concern in the ground water were below the cleanup target levels except for VC. Recommendations included continuing in situ biostimulation treatment on a monthly basis, plus additional excavation to remove contaminated soil beneath the concrete floor slab.

Jones Chemicals, Inc. Record of Decision (2000)
and
Jones Chemicals, Inc. (Superfund)
U.S. EPA Region 2, Oct 2006
Contact: George Jacob, RPM, 212-637-4266, jacob.george@epa.gov

The 10-acre site was used for chemical manufacturing and repackaging of chlorine, anhydrous ammonia, various acids, chlorinated solvents, and petroleum products. It is now used to produce sodium hypochlorite and continues packaging chlorine, sulfur dioxide, mineral acids, and other chemicals. Tanks were removed, and in 1996 a P&T pilot began to remove PCE, TCE, DCE, and other VOCs (toluene, methylene chloride, chloroform) from groundwater via air stripping, achieving 99% contaminant removal. Treated water is used in current manufacturing and discharged into on-site lagoons. Since the 2000 ROD, cleanup involves SVE for soil around a former aboveground tank, continued P&T, in situ chemical injections for groundwater hot spots, and MNA. To date, air stripping has treated 500 million gallons and the SVE system has removed 94 pounds of PCE/breakdown products. The source is still unidentified, so an air stripper was added to the local municipality's water supply.

MacKenzie Chemical Works (Superfund)
October 2006
Contact: Mark Granger, 212-637-3351, granger.mark@epa.gov

This 1.4-acre site was used to manufacture chemical products, including fuel additives and metal acetylacetonates, which were released from/at tanks, drums, lagoons, cesspools, and storm-water drywells. Site contaminants include TCP, PCE, TCE, SVOCs, PAHs, and metals. The 2003 ROD states that DNAPL is likely present. Remedy construction began in 2004. Limited excavation and off-site soil disposal was conducted. VOC-contaminated soil is treated via thermally enhanced SVE, which is anticipated to continue through 2011. In situ ground-water treatment began with injections of a light oxidant (ozone), but progressed to a stronger oxidant (sodium persulfate) after successful pilot studies in 2006.

Ogallala Ground Water (Superfund)
U.S. EPA Region 7, May 2003
Contact: Diane Easley, 913-551-7797. easley.diane@epa.gov

This site along the South Platte River contains 2 OUs: OU1 resulted from past manufacturing of electrical equipment, and OU2 is associated with dry cleaning solvents. Contaminants include TCA, PCE, TCE, CT, and BTEX. For OU1, the 1999 ROD selected continuation of an extraction and treatment system and potential MNA. For OU2, SVE began operating in 2002 and removed 114 pounds of PCE by year's end, nearly reaching cleanup goals for soil. In 2003, chemical oxidation was implemented in the most contaminated part of plume. The 2006 ROD specified chemical oxidation for the entire plume.

Optimization of a Chemical Oxidation Treatment Train Process for Groundwater Remediation
G. Cronk.
The 5th International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 2006, Monterey, California.

A novel combined peroxide/persulfate strategy for in situ chemical oxidation (ISCO) is effective for the cleanup of volatile organic contaminants in ground water, especially at sites with high levels of adsorbed mass. The ISCO treatment train begins with Fenton's reaction. Heat and hydroxyl radicals given during the reaction then activate sodium persulfate. At the optimum temperature range of 140 to 180 degrees F, hydroxyl radicals and superoxide radicals are generated without excessive decomposition of the hydrogen peroxide. The combined effect of the free radicals and elevated temperatures is very effective for the desorption of contaminants from soil particles and the mass transfer of contaminants into a dissolved phase. Because the Fenton's reaction lasts only 4 to 10 hours, it may be expended before the dissolved-phase contaminants are destroyed, but when used with activated persulfate, which is active for up to 30 days, the sulfate radicals continue to attack the residual dissolved mass. The combined use of activated persulfate and catalyzed hydrogen peroxide can result in substantial cost savings by eliminating the contaminant rebound effect and the repeated applications often required when performing conventional ISCO treatment. This ISCO treatment train has been used successfully on petroleum hydrocarbons, chlorinated hydrocarbons, MTBE, methylene chloride, 1,4-dioxane, PCBs, and PAHs. A list of completed ISCO treatment train projects appears at the end of the paper.

Pemaco (Superfund)
U.S. EPA Region 9
Contact: Rosemarie Caraway, 415-972-3158, caraway.rosemarie@epa.gov

Pemaco is a 1.4-acre site formerly used for chemical mixing operations that used numerous aboveground USTs and other storage vessels. Contaminants include PCE, TCE, TCA, DCA, VC, toluene, and xylenes. Removal actions were taken in 1997 following an extensive fire. Early cleanup involved SVE, thermal oxidation, and GAC filters. The 2005 ROD selected (1) a soil cover and revegetation for the surface and near-surface soils; (2) a high-vacuum, dual-phase extraction system with UV oxidation and GAC for water treatment and flameless thermal oxidation and GAC for vapors from the upper vadose soils and perched groundwater; and (3) electrical resistance heating (ERH) with vapor extraction, vacuum-enhanced groundwater extraction, P&T, and MNA for the lower vadose soil and exposition groundwater. UV oxidation and GAC will be used for water treatment and flameless thermal oxidation and GAC for vapors. ERH design was scheduled for completion in 2006, along with treatment startup for groundwater and vapors.

Sangamo-Weston, Inc./Twelve Mile Creek/Lake Hartwell PCB Contamination Superfund Site, Pickens, Pickens County, South Carolina
U.S. EPA Region 4, Superfund Information System.

The land-based source areas of OU-1 include the Plant site and six satellite disposal areas, as well as contaminated groundwater associated with the land-based source areas. From December 1995 through May 1997, ~40,000 cubic yds of PCB-impacted material was removed from the satellite disposal areas and consolidated on the Plant site for treatment by low-temperature thermal desorption (to ~2 mg/kg PCBs) and then backfilled on site. Two pump-and-treat systems installed at the Breazeale and Plant sites collectively have recovered 215 million gallons of groundwater and removed 1,480 pounds of chlorinated solvents (mainly PCE and TCE) and 17.6 pounds of PCBs (primarily Aroclor 1248). In 2008, 9 pilot SVE wells were installed at suspected residual source areas on the Plant site, and their VOC removal efficiencies will be evaluated to determine if full-scale SVE is warranted. In 2007, pilot studies were implemented at the Breazeale site to evaluate ozone sparging and potassium permanganate as possible ISCO technologies to reduce the VOC plume. Based on the results, a ROD amendment was signed and full-scale ISCO using potassium permanganate was conducted in September 2009. SVE Pilot Study ISCO Pilot Study Sediment MNR.

Second Five-Year Review Report for Tibbetts Road Superfund Site, Town of Barrington, Strafford County, New Hampshire
U.S. EPA Region 1, Boston, MA. 79 pp, 2008

EPA completed the first 5-year review in September 2003. Monitoring continues at the site to assess the effectiveness of the reduction of ground-water contaminants (acetone, toluene, benzene, xylenes, PCE, TCE, MIBK, PCBs, and metals) by a vacuum-enhanced recovery system for hot-spot remediation, phytoremediation via 1,600 poplar trees, and intrinsic biodegradation. An ISCO pilot injection program began in November 2003 with the injection of 100 gal of sodium permanganate, followed by injection of 55 gal in December 2003. The initial ISCO pilot treatment successfully reduced many of the chlorinated and non-chlorinated organics, but benzene was not reduced significantly; future injections would require longer reaction times. A second phase of ISCO pilot injections took place in June and November of 2006. EPA's second 5-year review of the remedy confirms that progress is being made in site cleanup and that the soil and ground-water remedies already in place continue to be protective, but the restoration timeframe to attain the interim cleanup levels likely will take longer than the 2012 estimate.

USA Defense Depot Memphis
U.S. EPA Region 4 Web site.

The most consistently detected VOC group of chemicals at concentrations above comparison criteria in the site media are CVOCs, such as TCE, PCE, 1,1,2,2-PCA, carbon tetrachloride, and chloroform. The final ROD (2004) for Dunn Field calls for excavation and off-site disposal of the contents of pits and burial trenches, SVE of principal-threat waste in the unsaturated subsurface soils, treatment of the groundwater CVOCs via injection of ZVI, and installation of a ZVI PRB to address high groundwater concentrations downgradient of Dunn Field. SVE operation began in the VOC-contaminated sand and gravel layer beneath source areas in July 2007. In situ thermal desorption (ISTD) began in the VOC-contaminated silty clay zone (top 30 ft) in May 2008. VOC removals for all remedies to date (soil and groundwater) totals ~9,000 pounds. A revised proposed plan and ROD amendment are planned for 2009 to document changes undertaken to achieve the remedial action objectives of the original ROD.

Use of Large-Scale Electrokinetic and ZVI Treatment for Chlorinated Solvent Remediation at an Active Industrial Facility
Athmer, C.J.
Remediation Journal 24(4):41-51(2014)

A Lasagna™ system, which combines electrokinetic and ZVI technologies, uses a direct current electrical field to mobilize contaminants via electroosmosis and soil heating. The contaminants are intercepted and reduced in situ using treatment zones containing ZVI. Lasagna™ was implemented for soils contaminated with chlorinated solvents, including DNAPL, at an active industrial site in Ohio . The remediation systems were placed in tight clay soils beneath traffic areas without interruption to facility production. In the moderately contaminated soils around the actively treated source areas, a grid of ZVI-filled boreholes was installed for passive treatment of residual contamination. The active systems removed 80% of the TCE mass, while the passive ZVI borings continue to reduce the TCE. Cleanup goals have been met, and the site is now in monitoring-only mode to track contaminant attenuation. Additional information: 35 slides

Xerox Corporation, Joseph C. Wilson Center for Technology-Webster (RCRA)
U.S. EPA Region 2, Sep 2003
Contact: Rachel Chaput, 212-637-4116, chaput.rachel@epa.gov

The 1,000-acre site was used for research, development, and manufacturing and/or refurbishing of electrostatic copying machines and associated consumables. It encompasses 106 SWMUs, 80 of which require NFA but the others each have VOCs (TCE, TCA, DCE, DCA, toluene, vinyl chloride) and some have metals (Cr). Major activities involve 7 areas. Treatment includes P&T, blasting of bedrock trenches to enhance groundwater recovery, two-phase (water/vapor) extraction, and soil excavation in source areas. Groundwater recovery activities initiated in 1986 included several two-phase extraction systems (at one point, using 65 wells), which are being phased out due to diminishing mass-recovery returns and replaced by groundwater P&T. During 2002, 39,000,000 gallons of contaminated groundwater and 87,000,000 cubic feet of aspirated air were recovered and treated, resulting in the removal of 330 pounds of contaminant mass. A corrective measures study should be at/near completion to select the final, single remedy for the entire site.

PCE

Combined ISCO, ERD, and Biobarrier Strategy for DNAPL Site at Camp Lejeune
Propst, B., M. Fulkerson, C. Bozzini, D. Cleland, and C. Rychak.
Eighth International Conference on Remediation of Chlorinated & Recalcitrant Compounds, Monterey, California, May 21-24, 2012. Poster, 2012

Dry cleaning activities at Site 88 released PCE, which resulted in a DNAPL plume along with a 0.75-mile groundwater plume. The PCE source area was treated successfully using soil mixing with addition of ZVI and clay. From October through December 2010, the groundwater plume was treated using ISCO with 2.5% potassium permanganate at a depth of 50 ft, and enhanced reductive dechlorination with SRS(r) and bioaugmentation at a depth of 100 ft. In addition, an injected biobarrier containing Three-Dimensional Microemulsion (3DMe(tm)) with bioaugmentation was installed to intercept and treat the downgradient groundwater flow. The anticipated treatment ROI was not met, but where substrate or chemical oxidant was distributed, promising results were observed.

Coupling Aggressive Mass Removal with Microbial Reductive Dechlorination for Remediation of DNAPL Source Zones: A Review and Assessment
J.A. Christ, C.A. Ramsburg, L.M. Abriola, K.D. Pennell, and F.E. Loeffler. Environmental Health Perspectives, Vol 113 No 4, p 465-477, 2005

This article reviews available laboratory and field evidence that supports the development of a treatment strategy that combines aggressive DNAPL source-zone removal technologies with subsequent promotion of sustained microbial reductive dechlorination. The focus here is on PCE.

Demonstration of Bioaugmentation to Enhance Chemical Oxydation [sic] Results [abstract only]

Effects of the Nonionic Surfactant Tween 80 on Microbial Reductive Dechlorination of Chlorinated Ethenes [abstract only]

Field Evaluation of the Solvent Extraction Residual Biotreatment (SERB) Technology
S.C. Mravik and A.L. Wood.
Research Brief, 2 pp, 2003

Enhanced source remediation by in situ flushing and bioremediation by reductive dechlorination were combined in a treatment train to address PCE contamination at the site of a former drycleaner.

Successful Pilot Test of Electrokinetic-Enhanced Bioremediation (EK-BIO) as an Innovative Remedial Approach for PCE DNAPL Source Area
Riis, C., M. Bymose, E. Cox, J. Wang, D. Gent, and M. Terkelsen.
NORDROCS 2012: 4th Nordic Joint Meeting on Remediation of Contaminated Sites, International Conference, September 18-21, 2012, Oslo, Norway. 4 pp paper and 23 slides, 2012

Electrokinetic (EK) injection presents an alternative for efficient and uniform delivery of bioremediation additives (e.g., bacteria, nutrients) into low-permeability soil. A successful 74-day pilot study of this EK-bio technique for remediation of PCE DNAPL was conducted at a site in Skuldelev, Denmark. Paper and Slides

Soil Vapor Extraction, Pump and Treat, and In Situ Chemical Oxidation at Dry Clean USA No. 11502, Orlando, Florida
Federal Remediation Technologies Roundtable Cost and Performance Database, 2007

Dry Clean USA No. 11502 operated from 1988 to 1998. PCE was detected at a maximum concentration of 27,300 µg/L in the groundwater, indicating the possible presence of DNAPL. The area of the plume was estimated to be 70,000 sq ft. Site investigations conducted in 1997 accurately defined the source area at the facility and assessed the horizontal and vertical extent of chlorinated solvents in the subsurface. These investigations indicated that an area of elevated concentrations of chlorinated solvents existed in the soil and groundwater, extending ~300 ft east-southeast of the facility. After a successful pilot test in April 1998, SVE was chosen to remediate the contaminated site soil. P&T using an aboveground air stripper was selected to contain the contaminant plume and remediate the groundwater. The SVE system operated from April 1999 to December 2000, and the P&T system operated until November 2002. MNA was the remedy at the site after deactivation of the P&T system. In July 2004, increased concentrations of PCE were detected in samples from one source area well. In situ chemical oxidation with hydrogen peroxide was used to address PCE in the vicinity of the well to expedite remediation of this hot spot.

Streamlined Remediation System Evaluation, Wash King Laundry Superfund Site, Pleasant Plains Township, Michigan
U.S. EPA, Office of Superfund Remediation and Technology Innovation.
EPA 540-R-11-019, 55 pp, 2011

Placed on the NPL in 1983, remedy implementation to address PCE and its breakdown products began in 1999. The pump-and-treat (P&T) and SVE systems were fully operational in 2001. In situ bioremediation of the groundwater and saturated soils in the vicinity of the former laundry began in January 2010 using the Oppenheimer Formula CL product, which involves injection of microorganisms, a biocatalyst, and nutrients. Each of six injection arrays received 250 lbs of product mixed with 2,000 gals of water. The injections were repeated in September 2010, with a similar bioremediation event scheduled for 2011. This streamlined RSE focuses on the P&T and SVE systems, in situ bioremediation project, and site-wide monitoring program.

TCE

Air Force Plant 4 (Superfund)
U.S. EPA Region 6, Feb 2006
Contact: Robert Sullivan, 214-665-2223, sullivan.robert@epa.gov

Manufacturing and degreasing processes resulted in waste oils, waste fuels, paint residues, used solvents, and process chemicals in soil and groundwater. Drinking water wells show no contamination but contaminants were detected in 2 on-site creeks. Contaminants were found in the shallow Terrace Alluvium Aquifer and the upper Paluxy Aquifer. An SVE system in Building 81 began operating in 1994 and has since expanded. To enhance TCE DNAPL recovery, about 22,000 sq ft of soil below the building were heated to 90 degrees C by 73 electrodes at depths of 35 feet over 8 months. From 1993 to 2002, a vacuum-enhanced vapor/groundwater recovery system operated, and presently a full-scale P&T system operates at a parking lot. In addition, operation of a PRB (1,170 ft long, 2 ft wide, 35 ft deep) at the leading edge of the TCE plume occurred in 2002, achieving a 1,500-ft plume retraction.

Combining Low-Energy Electrical Resistance Heating With Biotic and Abiotic Reactions for Treatment of Chlorinated Solvent DNAPL Source Areas
Macbeth, T., M.J. Truex, T. Powell, and M. Michalsen.
ESTCP Project ER-200719, 383 pp, 2012

Low-temperature subsurface heating was combined with either ZVI or in situ bioremediation to enhance DNAPL remediation performance through both increased degradation reaction rates and contaminant dissolution. Moderate heating and minor operational costs enhanced efficiency and effectiveness of in situ treatment of TCE. Capture and treatment of contaminated vapor—a major cost element of standard thermal treatment—was not needed as the heating infrastructure was limited to subsurface electrodes and a power control unit. See also the 2015 ESTCP Cost & Performance Report

Commodore Semiconductor Group (Superfund)
U.S. EPA Region 3, Dec 2006

The site was formerly used to manufacture computer chips, and waste solvents (TCE) were stored in 2 USTs later found leaking. Air strippers have been used since 1984 to treat groundwater affecting nearby drinking-water wells. Household carbon units were installed at high-risk residences and construction of municipal water-line extensions was initiated. In 2000, a P&T system began treating groundwater at a rate of 85 gal/min. In 2003, P&T enhancement involved full-scale vapor extraction to remove vapors from soil and bedrock, and chemical oxidation to treat residual contaminants in soil near and beneath the building. Phase II focused chemical oxidation on contaminants in shallow bedrock that are sources of continuing contamination. Chemical oxidant injection into the deeper portions of the aquifer is expected to demonstrate that the technique can be used to clean groundwater in place to depths of 100 feet. The 2005 5-year review determined that P&T will continue until goals are met, supplemented by institutional controls. In 2006, carbon filters were installed on 2 drinking water wells in case chemical oxidant reaches the wells during injection, but the filters were suspected of causing increased copper concentrations in the drinking water and subsequently removed.

Fourth Five-Year Review Report for Outboard Marine Corporation Superfund Site, Waukegan, Lake County, Illinois
U.S. EPA Region 5, Chicago, IL. 71 pp, June 2012

The 2009 ROD for groundwater and DNAPL cleanup called for (1) soil mixing to incorporate ZVI and bentonite clay into the TCE DNAPL plume to accomplish in situ contaminant destruction; (2) injection of a soluble substrate (e.g., sodium lactate) into five VOC-contaminated source areas over multiple years to enhance in situ anaerobic bioremediation; (3) installation of an air sparge curtain to prevent off-site migration of dissolved chlorinated VOCs in groundwater; and (4) post-construction MNA and ICs until final cleanup levels are reached. EPA commenced air sparging in 2011, and Illinois EPA will take over system O&M in 2012. ZVI-bentonite mixing in the DNAPL plume area was completed in December 2011. Because of the location of one of the five identified VOC source areas, the in situ bioremediation remedy there was modified to a single ISCO injection (sodium permanganate) in May 2012. The other bioremediation injections will be conducted after evaluation of the effect of ISCO and any changes in groundwater flow following site building removal.

Impacts of Co-Solvent Flushing on Microbial Populations Capable of Degrading Trichloroethylene
V. Ramakrishnan, A.V. Ogram, and A.S. Lindner.
Environmental Health Perspectives, Vol 113 No 1, p 55-61, 2005

This study assessed the impact of ethanol flushing on the numbers and activity potentials of TCE-degrading microbial populations present in aquifer soils taken immediately after and 2 years after ethanol flushing of a former dry cleaners site.

New Advancements for In Situ Treatment Using Electrical Resistance Heating
T. Powell, G. Smith, J. Sturza, K. Lynch, and M. Truex.
Remediation, Vol 17 No 2, p 51-70, 2007

At the Fort Lewis, Washington, East Gate Disposal Yard, chlorinated solvents (primarily TCE) and petroleum products are being treated in situ in several contaminant source areas using electrical resistance heating (ERH) and multiphase extraction. This paper updates the progress of the project and discusses data that provide insights into the biotic and abiotic degradation processes observed throughout the range of operating temperatures.

North Penn Area 5 (Superfund)
U.S. EPA Region 3, Feb 2007
Contact: Kelley Chase, 215-814-3124, chase.kelley@epa.gov

The 35-acre facility manufactured electronic communication systems and mechanical equipment. Solvents and degreasers were used extensively, and TCE, PAHs, and hazardous inorganics have been detected in site soil and groundwater. In 1981, 125 cubic yards of contaminated soil from an UST area was removed and disposed of off site. P&T began the same year, initially with treatment at a nearby sewage treatment plant but with air stripping beginning in 1986. The final 2006 work plan calls for chemical oxidation while controlling further migration of contaminated groundwater though P&T at OU1 and OU3. Additional investigation is necessary for OU2. Field work should begin in Spring 2007.

The Potential for Reductive Dechlorination After Thermal Treatment of TCE-Contaminated Aquifers
Anne Kirketerp Friis
Technical University of Denmark, PhD Dissertation 74 pp, 2006

This thesis presents the results of an investigation of �the potential for reductive dechlorination after thermal treatment of TCE-contaminated aquifers� with focus on reductive dechlorination of trichloroethene (TCE) after electrical resistance heating (ERH).

Remediation of DNAPL through Sequential In Situ Chemical Oxidation and Bioaugmentation
D. Major.
ESTCP Project ER-0116, 92 pp, 2009

This project was conducted to assess the technical feasibility of sequential application of in situ chemical oxidation (ISCO) and in situ bioremediation (ISB) and to identify the optimal timing of the transition from ISCO to ISB. The field demonstration was conducted at Launch Complex 34, Kennedy Space Center, Florida, where an extensive TCE DNAPL source is present in the groundwater. In 1999, a demonstration of ISCO using potassium permanganate at LC-34 was completed in a 75 ft x 50 ft test plot. Construction of a groundwater recirculation treatment system was initiated and completed in 2003, and injections of ethanol (ISB, or biostimulation) and KB-1 (bioaugmentation) took place in 2004. The system was operated between June 2003 and August 2004. Electron donor addition (ISB) after ISCO resulted in partial biodegradation of TCE, with complete biodegradation observed after bioaugmentation. ESTCP Cost and Performance Report

Sol Lynn Site (Superfund)
U.S. EPA Region 6, Mar 2007
Contact: Gary Miller, 214-665-8318, miller.gary@epa.gov

The 0.75-acre site, about one-quarter mile from the Astrodome, formerly was used for scrap-metal and electrical-transformer salvaging and chemical manufacturing. Shallow groundwater is at 20 feet bgs, and 9 water-bearing zones are above a depth of 200-feet. The top 4 water-bearing zones, which are contaminated, generally flow 17 to 68 ft/yr. PCBs and solvents were dumped on site. TCE in groundwater reached 790 ppm, and PCBs in soil reached 357 ppm; ~2,400 cubic yards of soil and 12 million gallons of groundwater were contaminated. Chemical dechlorination was initially chosen as the soil remedy, but field tests failed. Following a 1992 ROD amendment, 2,281 cubic yards of soil was excavated and disposed of off site, and soil cleanup was deemed complete. The initial ROD for groundwater involved P&T, which began in 1993. A total of 15.5 million gallons of groundwater was recovered before P&T was shut down in 2000, when it was determined that P&T would not achieve goals. The plume currently is expanding and migrating downgradient. A 1994 ROD amendment called for in situ bioremediation with MNA and institutional controls. Bioremediation beginning in Summer 2007 will involve injection of lactate, phosphate, and ammonia to a depth of 40 feet, followed by microbial injection.

Successful ISCR-Enhanced Bioremediation of a TCE DNAPL Source Utilizing EHC® and KB-1®
Peale, J.G.D., J. Mueller, and J. Molin.
Remediation Journal, Vol 20 No 3, p 63-81, 2010

Successful full-scale implementation of in situ chemical reduction (ISCR)-enhanced bioremediation of a TCE DNAPL source zone was conducted at an operating facility in Portland, OR. In the demonstration, concentrations of TCE were reduced rapidly to below the maximum contaminant level in less than 6 months following ISCR implementation using EHC® and bioaugmentation with the KB-1® consortium. EHC is a hydrophilic carbon/ZVI blend that promotes degradation of aliphatic hydrocarbons via microbial and abiotic pathways. The remedial action objective for the source area--TCE concentrations below 1% of the solubility limit, or 11,000 µg/L—was achieved in less than 12 months.

Using a Treatment Train to Optimize DNAPL Source Zone Remediation
P.J. Favara, M.A. Singletary, B. Nwokike, and S. Tsangaris.
Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey Callifornia, May 2006. Battelle Press, Columbus, OH.

Although individual technologies can be successful in removing significant amounts of mass from a DNAPL source zone, it is unusual for a single technology to achieve site closeout. A sequential combination of technologies or different technologies applied to various target treatment zones within the contaminated area is more likely to meet remedial action objectives. The authors discuss the cleanup of DNAPL (primarily TCE) contamination at the former Orlando Naval Training Center, Study Area 17 site and describe the remedial process optimization approach used to assess the effectiveness of in situ chemical oxidation followed by natural attenuation in one zone and enhanced reductive dechlorination in the other zone to meet remedial action objectives.

Vestal Water Supply Well 1-1 (Superfund)
U.S. EPA Region 2, Aug 2006
Contact: Sharon Trocher, RPM, 212-637-3965, trocher.sharon@epa.gov

The site encompasses a single water-district well on the bank of the Susquehanna River and adjacent to an industrial park with marshy areas and drainage ditches. Soils in the industrial park contained significant levels of VOCs (TCA and TCE) in two locations. Well 1-1 now is used as an extraction well to treat contaminated groundwater through an air-stripping facility. Soil at 1 of 2 target areas underwent SVE treatment from 1997 until 2000, when treatment was determined to be complete. A total of approximately 1,046 pounds of VOCs were removed, and approximately 17,000 cubic yards were treated. Cleanup goals were achieved. Construction of an SVE system in the 2nd area began in 2003. By November 2005, high levels of VOCs remained in deeper soil, the capillary zone, and in groundwater. Supplemental treatment will be needed since the SVE system is removing VOCs only from the vadose zone and not from the saturated zone. The SVE system was scheduled to shut down in January 2006 and will restart when a treatment system for the saturated zone is installed, which is expected to occur by the Summer of 2007. From June 2003 through January 2006, SVE at this area resulted in removal of a total 2,100 pounds of VOC mass. Groundwater monitoring is conducted to determine the need for future treatment for heavy metals. Across the site, the groundwater pump-and-treat air-stripping facility treated a total of 2.8 billion gallons of contaminated groundwater over 9 years of operation. A 5-year review of the site was conducted in 2003.