U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)

Treatment Technologies

Thermal Processes: In Situ

Electrical Resistance Heating

Halogenated Alkenes

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General Resources | Case Studies: Chlorinated Solvent Mixtures | Case Studies: PCE | Case Studies: TCE | TCE: Abstracts

General Resources

Adobe PDF LogoIn Situ Thermal Treatment of Chlorinated Solvents: Fundamentals and Field Applications
U.S. EPA. EPA 542-R-04-010, 145 pp, 2004

Contains information about the use of in situ thermal treatment technologies to treat chlorinated solvents in source zones containing free-phase contamination or high concentrations of contaminants that are either sorbed to soil or dissolved in groundwater in the saturated or unsaturated zone.

Case Studies: Chlorinated Solvent Mixtures

Adobe PDF LogoCost and Performance Review of Electrical Resistance Heating (ERH) for Source Treatment: Final Report
A. Gavaskar, M. Bhargava, and W. Condit.
Naval Facilities Engineering Service Center, TR-2279-ENV, 133 pp, 2007

The five projects examined in this review took place at four Navy sites and one NASA site, all affected primarily by one or more chlorinated solvent DNAPLs:

  • Naval Weapons Industrial Reserve Plant Bedford (primarily TCE, plus 1,1,1-TCA, PCE, and breakdown products);
  • Naval Complex Charleston (PCE and breakdown products);
  • Former Naval Air Station Alameda (vinyl chloride, DCA, 1,2-DCA, 1,1-DCE, trans-1,2-DCE, cis-1,2-DCE, 1,1,1-TCA, 1,1,2-TCA, TCE, and PCE);
  • Marine Corps Base Camp Lejeune (1,1,2,2-PCA and TCE); and
  • Cape Canaveral Air Station (TCE and PCE).
  • 2008 Addendum: U.S. Naval Station Annapolis (TeCA, TCE, 1,1,2-TCA)Adobe PDF Logo

Adobe PDF LogoInnovative Technology Summary Report: Six Phase Soil Heating
U.S. DOE, DOE/EM-0272, 31 pp, 1995

Discusses a demonstration of six-phase resistive heating at DOE's Savannah River M Area site. Key results: 99.7% of contaminants were removed from within the electrode array. Outside the array, 93% of contaminants were removed at a distance of 8 feet from the array. This difference indicates that heating accelerates the removal of contaminants. Temperatures within the array were elevated to 100°C after 8 days of heating and were maintained for 17 days. Eight feet outside the array, temperatures were elevated to 50°C. Clays were heated more rapidly than the adjacent sands. The efficiency of contaminant removal increased with increased soil drying due to heating. 19,000 gallons of condensed steam were removed from the extraction well, indicating substantial drying of the soil. Offgas concentrations showed little change during heating, most likely because the soil vapor extraction system affected an area of influence greater than the area of heating.

Contact (2007): Rosemarie Caraway,, 415-972-3158

Pemaco is a former chemical mixing facility located in a light industrial and residential area in Maywood, CA. Hazardous substances known to have been used at the facility since the late 1940s included chlorinated solvents (PCE, TCE, TCE, and DCA), aromatic solvents, and flammable liquids. The remedy selected for the site calls for (1) a soil cover and revegetation for the surface and near-surface soils; (2) a high-vacuum, dual-phase extraction system for the upper vadose soils and perched groundwater with UV Ox and GAC for water treatment and flameless thermal oxidation (FTO) and GAC for treatment of vapors; and electrical resistance heating with vapor extraction for the lower vadose soils and groundwater, vacuum-enhanced groundwater extraction, groundwater pump and treat, and monitored natural attenuation.

Electrical Resistive Heating at Poleline Road Disposal Area (PRDA), Arrays 4, 5, and 6, Fort Richardson, Alaska
Federal Remediation Technologies Roundtable Cost and Performance Database, 2003

The Poleline Road Waste Disposal Area (PRDA) was used as a disposal area from 1950 to 1972. Results of a site investigation that soil and groundwater has been contaminated with chlorinated solvents, including TCE, PCE, and TCA. A field demonstration was conducted to evaluate the effectiveness of ERH in reducing the concentration of chlorinated solvents in groundwater. The estimated mass of TCE, PCE, and TCA removed in the off-gas was 1,385 lbs. The ERH system reduced groundwater concentrations of TCA, PCE, and TCE an average of 49, 75, and 56%, respectively, but at the end of the demonstration, concentrations of TCA, PCE, TCE, and cis-1,2-DCE were above the remedial action objectives. The ERH system reduced soil concentrations of TCA and PCE to below the remedial action objectives; however, TCE concentrations remained above the remedial action objectives.

Adobe PDF LogoThermal Remediation: Two ERH Case Studies
Waldron, J.
In-Situ Thermal Remediation Workshop, 13-14 June 2012, Westford, MA. Northeast Waste Management Officials' Association (NEWMOA), 22 slides, 2012

During the recycling of hazardous chemicals, mainly chlorinated VOCs, at the Silresim site (Lowell, MA), the site became contaminated with VOCs, SVOCs, pesticides, and PCBs. An ERH system for source removal was completed July 2011, comprising 204 electrodes, 50 vapor extraction wells, and 77 multiphase extraction wells. Operation of the ERH system in shallow and deep overburden from July 2011 through February 2012 used 9.6 million Kwh of electricity to remove an estimated 40,000 to 86,000 pounds of VOCs, including 3,480 lbs of NAPL. [Note: Groveland Wells 1 & 2 is the other case study in this presentation.] Additional information: 2011 Preliminary Closeout ReportAdobe PDF Logo; Superfund Site Progress Profile

Adobe PDF LogoU.S. Army Fort Richardson Alaska: Interim Remedial Action Report Operable Unit B - Poleline Road
U.S. Army Corps of Engineers - Alaska District, 55 pp, 2003

Historical information describes how relatively shallow (8 to 10 ft) trenches were dug and used for the disposal of a wide variety of debris, including chemical agent identification sets. During disposals, a layer of bleach/lime was laid in the bottom of the trench, and the disposal materials were placed on a pallet in the trench. Diesel fuel was poured on the materials and ignited with thermal grenades. After burning was complete, a mixture of either bleach or lime, combined with chlorinated solvent carrier (TCE, PCE, and 1,1,2,2-PCA), was poured over the materials to neutralize any remaining chemical material. The remedy used a high-vacuum soil vapor extraction system and ERH to reduce contaminant levels in selected hotspots. In the treatment area, approximately 99.9% of the 1,1,2,2-PCA present before treatment was removed from the soil. Removal of PCE ranged from 79.5 to 99.6%. Removal of TCE ranged from 68.5 to 97.2%.

Case Studies: PCE

Camelot Cleaners, West Fargo, North Dakota
DNAPL Remediation: Selected Projects That Have No Further Action Status, Status Update
Contact (2007): Joyce Ackerman,, 303-312-6822

The site is an operating drycleaners that uses PCE as its cleaning solvent. The cleanup foot print is about 10,300 square ft with depths ranging to 56 ft bgs. The area includes part of the yard of an occupied residence. Deployment of the electrical heating system included 56 multi-zone electrode/vent assemblies and several horizontal soil vapor extraction wells. In especially clayey horizons, the extraction wells were augmented with dual vacuum extraction wells. Soil temperatures were measured with temperature monitoring piezometers. Nine multi-level monitoring wells were installed around the perimeter of the site to monitor existing conditions, cleanup success, and ensure that any subsurface migration of contaminants would be detected. The system removed about 5,188 pounds of contaminants. EPA confirmation sampling indicated that soil contamination had been reduced by 99.96 to 100% and groundwater concentrations by 99.98%. Only one area had concentrations of PCE over 3 mg/kg and all the groundwater samples were under 1 mg/L. The site is now in a no further action/no further groundwater monitoring required status.

Adobe PDF LogoEnhanced In Situ Biodegradation of PCE Following Electrical Resistance Heating at a DNAPL Source Area
C. Hudson, D. Williamson, and G. Beyke.

Discusses the remediation of a PCE DNAPL and associated plume at a former dry cleaner at the Charleston Naval Complex. The electrical resistance heating was successful in removing source zones; application of potassium lactate following the heating indicated that biostimulation would be effective in a polishing step.

Electrical Resistive Heating at Charleston Naval Complex, AOC 607, North Charleston, South Carolina
Federal Remediation Technologies Roundtable Cost and Performance Database, 2005

Charleston Naval Complex area of concern (AOC) 607 consisted of a former dry cleaning facility. PCE was one of the primary chemicals used, stored, disposed of, and accidentally released at the site. A RCRA Facility Investigation conducted in 1996 and 1997 detected dissolved-phase chlorinated solvents in the saturated zone, including PCE, TCE, cis-1,2-DCE, 1,1-DCE, and VC. In addition, PCE in the form of DNAPL appeared to have migrated into the shallow saturated zone. Initial maximum contaminant concentrations were 18,000 µg/L of total VOCs and 8,090 µg/L of PCE. In general, ERH resulted in a decrease in the area of the plume and a decrease in the number of high concentration zones. In March 2004 (22 months after ERH shutdown), PCE was detected in a monitoring well at a concentration of 283 µg/L. This suggested a 95% reduction in concentration compared to the pre-treatment baseline. Total VOCs concentration decreased by 83%. Total CVOCs and PCE mass recovered during ERH system operation was calculated at 247 and 234 lbs, respectively.

Adobe PDF LogoRemoval Action Completion Report: Electrical Resistance Heating in Source Area, Former Mercury Cleaners Site Area, 1419 16th Street, Sacramento, California
California Regional Water Quality Control Board, Central Valley Region, 1102 pp, 2018

Soil and groundwater treatment to remediate the impacts of petroleum-based Stoddard Solvent and of PCE and its daughter products at the Mercury Cleaners site began in 2015 with an SVE system pilot test, which is still operating. A source area removal action was implemented in an area ~40 ft by 40 ft in November 2016 using an in situ ERH thermal desorption system comprising 15 electrode/vapor recovery wells located within the source area and connected to the SVE system. The ERH system discontinued operation on July 7, 2017. Although source area cleanup goals were not met completely, significant PCE mass was removed from the source area.

Case Studies: TCE

Adobe PDF LogoDemonstration of Resistive Heating Treatment of DNAPL Source Zone at Launch Complex 34 in Cape Canaveral Air Force Station, Florida. Final Innovative Technology Evaluation Report
Gavaskar, A., et al.
Report No: EPA 540-R-08-004, 133 pp + 241 pp of Appendices, Aug 2008

Adobe PDF LogoFinal Enlarged Electrical Resistive Heating Application Construction and Performance Report, Building 181 Trichloroethene Source Area, Air Force Plant 4, Fort Worth, Texas
Air Force Center for Environmental Excellence, 2004

Describes the installation and operation of an electrical resistance heating system at Building 181, concluding that remedial action objectives were met. Also includes cost data and lessons learned.

Adobe PDF LogoGroveland Wells Numbers 1 and 2 Superfund Site — Operable Unit 2: Final Remedial Action Report
U.S. EPA Region 1, 115 pp, 2011

Construction of an electro-thermal dynamic stripping process (ET-DSP(tm)) system, which combined ERH with SVE and multiphase extraction, was completed in four contiguous in situ thermal treatment areas in August 2010 and operated until February 2011 under EPA and Massachusetts DEP oversight. In total, the cleanup system operated for 192 days, removed 1,300 pounds of VOCS from the vadose and saturated zones, recovered over 18 gallons of pure TCE, pumped and treated over two million gallons of contaminated water and condensate, and extracted over 311 million cubic feet of gaseous vapors. Additional information: Superfund Site Progress Profile; FRTR Cost & Performance Report (2013)

In Situ Soil and Groundwater Decontamination Using Electric Resistive Heating Technology (Six-Phase Heating)
CL:AIRE Technology Demonstration Project Bulletin 26 (TDP 26), 6 pp, 2008

This bulletin describes the UK's first use of six-phase heating to accomplish source removal of contaminants resulting from historic contamination of a former tools manufacturing site. Investigations at the 2-hectare site showed high levels of dissolved, adsorbed, and free-phase chlorinated hydrocarbons, primarily TCE and vinyl chloride in the soil and TCE in the groundwater. Post-remediation validation sampling results showed final reductions in adsorbed and dissolved-phase TCE concentrations in excess of 98 and 99%, respectively, at the end of 20 weeks. System redesign and continuous close monitoring and optimization throughout the project maintained elevated contaminant extraction rates and allowed considerable savings.

Adobe PDF LogoNew 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.

Technology Cost and Performance: Electrical Resistive Heating at a Former Manufacturing Facility, Skokie, Illinois
Federal Remediation Technologies Roundtable Cost and Performance Database, 2000

A former electronics manufacturing facility located in Skokie, IL, began operations in 1958 and included machining, electroplating, heat-treating, silk screening, silicon chip production, and research and development. TCE and 1,1,1-TCA were chemicals associated with various manufacturing processes. Chlorinated solvents (TCE and 1,1,1-TCA, as well as degradation products cis-DCE and trans-DCE, 1,1-DCE, 1,1-DCA, vinyl chloride, and chloroethane); sampling indicated that DNAPLs were present in clays at depths of five to eight feet bgs, and in the soil pores from the water table (7 feet bgs) to depths of 18 to 20 feet bgs. Concentrations in ground water at the initiation of ERH for cis-DCE were as high as 160,000 µg/L, as high as 130,000 µg/L for TCE, and as high as 150,000 µg/L for 1,1,1-TCA. The ERH system initially consisted of a network of 107 electrodes, with 85 of the electrodes constructed beneath the floor of a warehouse building. After five months of operation, the system was shut down for about one month, while 78 more electrodes were installed (185 electrodes total). All electrodes were designed to be electrically conductive throughout a depth interval of 11 to 21 feet bgs and to increase the subsurface temperature in the depth interval of five to 24 feet bgs to the boiling point of water. A network of 37 soil vapor extraction wells, screened to five feet bgs, were used to capture vapors. The off-gas system consisted of a vacuum extraction blower and a steam condenser. The ERH process operated at the Skokie site from June 4, 1998, to April 30, 1999. Tier III cleanup goals were achieved for the three constituents of concern in all seven monitoring wells. In addition, contaminant concentrations in other wells were reduced to more stringent Tier I cleanup levels. For example, the Tier I cleanup level for 1,1,1-TCA was met in all seven wells, for cis-1,2-DCE in one well, and for TCE in two wells. The IEPA issued a letter on July 29, 1999, granting the site's request for No Further Action.

Adobe PDF LogoElectrical Resistive Heating at the ICN Pharmaceuticals Incorporated Site, Portland, Oregon
Federal Remediation Technologies Roundtable Cost and Performance Database, 2007

The ICN Pharmaceuticals site was used as a clinical laboratory from 1961 to 1980. Wastes from laboratory operations were disposed of in a 20 ft deep dry well. Results of sampling conducted in the vicinity of the former dry well showed elevated concentrations of VOCs, including TCE, cis-1,2-DCE, vinyl chloride, benzene, and toluene in the groundwater. The initial ERH system (May 2000 to May 2001) contained 60 electrodes with each capable of directing power to three zones 20-30 ft bgs, 34-44 ft bgs, and 48-58 ft bgs. The electrodes were placed in hexagonal arrays of 6 electrodes each, with a seventh neutral electrode in the middle of each array. The annular borehole spaces were packed with steel shot to improve conductivity and covered with an impermeable material. An SVE system, consisting of 53 vapor extraction wells, was used to recover the steam and contaminant vapors from the unsaturated region immediately above the heated region (5-10 ft bgs). As of December 2001, maximum groundwater contaminant concentrations in the Overbank layer had been reduced from 150,000 µg/L to 100 µg/L for TCE, from 370,000 µg/L to 1,300 µg/L for DCE, and from 24,000 µg/L to 50 µg/L for VC. Groundwater monitoring conducted in April 2005 indicated that U.S. EPA drinking water levels (MCLs) were exceeded in only a few of the shallow and intermediate OD monitoring wells located in the southwest portion of the site, and in one TGA monitoring well in the same area. The exceedances were slight and concentrations appeared to be declining. Evidence indicates that remaining groundwater contaminants are being eliminated by an active microbial population.

Electrical Resistive Heating Treatment of DNAPL Source Zone at Launch Complex 34, Cape Canaveral Air Force Station, Florida
Federal Remediation Technologies Roundtable Cost and Performance Database, 2003

A 1998 site investigation at the Cape Canaveral Air Force Station in Florida identified a large DNAPL source at Launch Complex 34. Chlorinated solvents, including TCE, were used in cleaning operations. ERH reduced the mass of TCE and DNAPL in the soil in the demonstration test plot by 90 and 97%, respectively, exceeding the target of 90% mass removal.

Adobe PDF LogoTechnical Performance Evaluation for Phase I of the C-400 Interim Remedial Action at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky
U.S. DOE, Portsmouth/Paducah Project Office.
DOE/LX/07-1260&D1, 190 pp, Aug 2011

Phase I implementation of ERH was conducted as the C-400 IRA remedy to remove VOC contamination, mainly TCE, from subsurface soils. Full operation began at the end of March 2010, and heating ended at the end of October 2010, while SVE continued until all system operations ended on December 4, 2010. Post-operational sampling results show average percent reductions in contaminant concentrations of 95% for soil and 76% for groundwater in the east area, and 99% for both soil and groundwater in the southwest area. Target temperatures were not attained in the electrically resistive deep regional gravel aquifer due to groundwater flow velocity, formation resistivity, and heat loss by convective flow.

Adobe PDF LogoTreatment Using Electrical Resistance Heating (ERH) of Source Area CVOCs at a Former Manufacturing Facility, Newtown, CT
Taddeo, A.
In-Situ Thermal Remediation Workshop, 13-14 June 2012, Westford, MA. Northeast Waste Management Officials' Association (NEWMOA), 31 slides, 2012

The remedial strategy for chlorinated VOCs at a former metal tubing manufacturing facility located next to a railroad line in a suburban woodland/wetland area called for ERH in the source area and in situ bioremediation for the adjacent area and off-site plumes. ERH treatment was designed for a minimum duration of 4 months, with at least 30 days at 100 degrees C to reach 760 ppb or less TCE (reduction of 99.9% or greater) at an all-inclusive cost of $120/cy. Post-treatment residual TCE mass is very low, and the TCE mass flux has fallen below the TCE mass flux associated with the cleanup goal for the site. Additional information: ERH permitting concerns by the Connecticut DEEPAdobe PDF Logo

Adobe PDF LogoUse of Electrical Resistive Heating for the Remediation of CVOC and Petroleum Impacts in Soil and Groundwater, New York City, New York
Nichols, H.
In-Situ Thermal Remediation Workshop, 13-14 June 2012, Westford, MA. Northeast Waste Management Officials' Association (NEWMOA), 14 slides, 2012

ERH was implemented at a former industrial property located in New York City to address both petroleum and chlorinated VOC impacts. The targeted treatment depths varied between 25 and 40 ft below grade in an area of one-quarter acre, an estimated treatment volume of ~13,750 cubic yds. Shallow treatment was intended to address the area affected only by petroleum hydrocarbons, with intermediate treatment for the area affected by TCE and daughter products. During 283 days of ERH operation, the system removed over 3,200 lbs of VOCs from the site, including 2,800 lbs of TCE (equivalent to ~230 gallons of pure product). VOC groundwater concentrations were reduced over 99.99%.

TCE: Abstracts

Characterization and Remediation of a TCE Source Area Using Electrical Resistance Heating (ERH): Glendive, Montana
R. Dunning and J. Norris. 2007 Railroad Environmental Conference, October 23-25, 2007: Presentation abstracts. Illinois Railroad Engineering Program, p 17, 2007 [abstract only]