Dense Nonaqueous Phase Liquids (DNAPLs)

In Situ Oxidation

Halogenated Alkenes

Case Studies: Chlorinated Solvent Mixtures

Controlled Vadose Zone Saturation and Remediation (CVSR) Using Chemical Oxidation
Cronk, G., S. Koenigsberg, B. Coughlin, M. Travers, and D. Schlott.
The 7th International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 24-27, 2010. Battelle Press, Columbus, OH. 8 pp, 2010

CVSR was implemented with ISCO at an active industrial site in Illinois to address PCE, TCE, methylene chloride, ethylbenzene, toluene, and total xylenes in the soil. Alkaline-activated sodium persulfate using sodium hydroxide was applied to shallow soils to a depth of 15 ft. The vadose zone soils were saturated using a combination of vertical injection wells, an infiltration gallery, and horizontal injection wells installed beneath two small buildings. Due to the presence of low permeability silts and clays, the ROI of each vertical injection well was ~10 ft. About 4,700 gallons of sodium hydroxide (25% concentration) and 11,500 lbs of sodium persulfate were injected over a 27-day period in November/December 2008. A second injection of activated persulfate was performed in Area 1 in August 2009. The concentrations of the compounds of concern all decreased by 88 to 99% within 180 days after treatment.

Cooperative Technology Demonstration: Polymer-Enhanced Subsurface Delivery and Distribution of Permanganate
Crimi, M., J.A.K. Silva, and T. Palaia.
ESTCP Project ER-200912, 322 pp, Feb 2013

The use of a water-soluble polymer with permanganate for in ISCO of organic contaminants was demonstrated to improve the sweep efficiency of permanganate through heterogeneous media. In two injection wells at Marine Corps Base Camp Lejeune's TCE-contaminated Site 88, permanganate only was delivered to the control well, while permanganate and the polymers xanthan gum (for improved sweep) and sodium hexametaphosphate (for manganese dioxide by-product control) were delivered to the second well. The sweep efficiency doubled from 37% in the permanganate-only plot to 67% in the permanganate + polymer plot with one pore volume of amendment delivered. With polymer, preferential flow was reduced with no negative impact to injection pressure. Total costs of polymer-amended ISCO above traditional ISCO are estimated at ~$58 per cubic meter of treated media. Additional benefits of implementation can include lower injection volume, less field time, and lower probability of contaminant rebound. Additional information: Project ER-200912 Final Debrief; ESTCP Cost & Performance Report

Cost and Performance Report for Persulfate Treatability Studies
S. Rosansky and A. Dindal.
Naval Facilities Engineering Service Center, Port Hueneme, CA. TR-2333-ENV, 103 pp, 2010

Five persulfate pilot projects at four Navy sites and one Marine Corps site conducted between 2006 and 2009 yielded useful information on the performance of ISCO using different activators and under different site conditions. The demonstrations took place at Naval Air Station North Island (TCE, DCE); NAS Alameda (VC); Alleghany Ballistics Laboratory (TCE, 1,2-DCE, 1,1,1-TCA, methylene chloride, acetone); Marine Corps Base Quantico (1,2,4-trichlorobenzene, TCE, PCE, DCE, VC); and Washington Yard (LNAPL). ISCO at Washington Yard occurred in June 2009 and data were not available for this report. Performance data from the first 4 sites indicate that persulfate application was successful at reducing chlorinated solvent constituents; however, reductions were not uniform across the sites, possibly due to the difficulty of distributing the reagent evenly throughout the target treatment areas. Specific conclusions pertaining to contaminant reduction at the first four sites are provided.

Draft Removal Action Closeout Report: Time-Critical Removal Action, Installation Restoration Site 5, Unit 2, Naval Air Station North Island, San Diego, California
U.S., Department of the Navy, NAVFAC, San Diego, CA. 363 pp, 2003

The removal action was conducted 2002-2003 to mitigate a VOC groundwater plume by the use of ISCO in sequential application of hydrogen peroxide, Fenton's reagent, and potassium permanganate to reduce site contaminant mass to the extent that remediation by natural attenuation is an effective remedy for residual chlorinated aliphatic hydrocarbons in groundwater. Contaminant levels detected in the groundwater included cis-1,2-DCE at 19,000 µg/L, 1,4-dichlorobenzene at 21 µg/L, benzene at 180 µg/L, methylene chloride at 1,900 µg/L, PCE at 1,200 µg/L, TCE at 11,000 µg/L, VC at 48,000 µg/L, 2,4-dimethylphenol at 9,800 µg/L, acenaphthylene at 200 µg/L, and bis(2-chloroethyl)ether at 3,000 µg/L. Hydraulic fracturing was executed to enhance oxidant delivery. Based on the quantity of mass removed (2 tons of VOCs) and identified post-treatment site conditions, the TCRA goal was achieved.

Engineering Evaluation/Cost Analysis: Properties Immediately Adjacent to Marina Cliffs/Northwestern Barrel Site South Milwaukee, Wisconsin
U.S. EPA Region 5, 136 pp, 2006

This report contains information on the implementation and results of a full-scale in situ chemical oxidation (ISCO) pilot study conducted using the BIOX® technology (a proprietary oxidant now known as ChemOx®) in three areas affected by benzene, PCE, TCE, VC, and xylenes.

Fast-Track Remedial Design of Full-Scale ISCO Application Using Pilot Scale Testing and Field Screening Parameters
Dombrowski, P.M., B.A. Weir, K.M. Kelly, and J. Brown.
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy 15(16):169-194(2010)

At the Ottati and Goss Superfund Site in Kingston, NH, soil and groundwater contaminated with chlorinated VOCs, BTEX, and 1,4-dioxane were addressed with base-activated persulfate. This paper describes pilot test planning, performance monitoring, and full-scale design using data collected from the 2007-2008 pilot test for this fast-track remediation. The full-scale application was completed between July and September 2008. Additional information: Ottati & Goss/Kingston Steel Drum, Kingston, NH.

Final Report for Demonstration of In Situ Oxidation of DNAPL Using the Geo-Cleanse Technology
K.M. Jerome, B. Riha, and B.B. Looney.
WSRC-TR-97-00283, NTIS: DE98050456, 83 pp, 1997

In April 1997, in situ oxidation (Fenton's chemistry) was demonstrated at the A/M Area of the Savannah River Site to address a small groundwater plume and 600 lbs of DNAPL (TCE and PCE) in a 64,000 cubic ft soil treatment zone. A destruction efficiency of 94% was achieved in this small-scale test.

In Situ Chemical Oxidation at Four Dry Cleaner Sites, Various Locations
Federal Remediation Technologies Roundtable Cost & Performance Database, 2005

ISCO using either sodium or potassium permanganate was conducted at 4 dry cleaner sites—Former Cowboy, Springvilla, Rummel Creek, and Niles Finest—contaminated with chlorinated ethenes (primarily PCE and TCE) and some ethanes. The concentration of contaminants in groundwater varied by site with levels of PCE as high as 110,000 µg/L and TCE as high as 610 µg/L. Full-scale ISCO was implemented at all four sites. Reductions in contaminant concentrations following treatment were observed at all the sites except Niles Finest Cleaners, where PCE concentrations rebounded in both soil and groundwater after the injection of oxidant. Excavation has been proposed for the contaminated soil as an alternative to chemical oxidation. A lesson learned with this application is that when utilizing ISCO, rebound or increase of chlorinated solvents in groundwater should be carefully monitored, even where contamination in soil was the only initial concern.

In Situ Treatment at Three Dry Cleaner Sites, Various Locations
Federal Remediation Technologies Roundtable Cost & Performance Database, 2004

At the Former Market Place site, ISCO with ozone (ozone air sparge and C-sparging with ozone injection) was implemented in 2002, followed by MNA to address groundwater PCE contamination. At the Denver Colorado Dry Cleaner site, ISCO using ISOTEC's modified Fenton's reagent was implemented in 2 phases in 2001: 2 direct-push injection events inside the former dry cleaner building to treat the PCE/TCE source and 3 direct-push injection events to treat the entire groundwater plume. A total of 26,987 gallons of ISOTEC reagents was injected through 244 temporary injection locations. At the United Cleaners #1973 site, in situ heat-enhanced SVE was implemented in 2002 to address PCE, TCE, 1,1,1-TCA, VC, and 1,1-, cis-1,2-, and trans-1,2-DCE. A series of in-ground coils transferred heat, increased volatility of organic contaminants, and facilitated vapor extraction of volatile solvents from the soil.

Mass Reduction verses Mass Movement of Chlorinated Aliphatic Hydrocarbons During In Situ Chemical Oxidation Pilot Test
J. Shiple, R. Wong, M. Bonsavage, and W.E. Collins.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

A 3-injection event ISCO pilot test using traditional Fenton's chemistry resulted in significant reduction of chlorinated organics and other VOCs in an unconfined aquifer at a former liquid-waste disposal site. The shallow aquifer is contaminated with VOCs (e.g., cis-1,2-DCE, VC, and aromatic hydrocarbons) at concentrations greater than 100 ppm. Site soils also contain the above VOCs, as well as naphthalene and trichloropropane. Chemicals applied through a single injection well during the test were hydrochloric acid for pH adjustment, ferrous iron sulfate as a catalyst, and hydrogen peroxide as oxidant. Contaminant mass in groundwater calculated over the entire 30-ft radial pilot test area from groundwater samples taken before and after the test showed a decrease of 57%, about a 2.8 kg reduction, indicating mass destruction rather than migration. The calculated dilution effect of injected fluids within the 30-ft radius ranged from 6 to 11% over the course of the study. The results indicate that although movement of contaminant mass from the sorbed to dissolved and vapor phases apparently occurred in response to chemical injection, contaminant mass reduction was the predominant phenomenon occurring as a result of ISCO implementation at the site.

Record of Decision: Valmont TCE Superfund Site, Luzerne County, Pennsylvania
U.S. EPA Region 3, 151 pp, 2011

In situ treatment of the entire groundwater plume (TCE predominating) will be done by batch injection of a chemical oxidant (e.g., potassium or sodium permanganate) into the bedrock. EPA conducted a pilot study at the site between 2008 and 2010 to evaluate ISCO effectiveness as a stand-alone remedy by injecting a high volume (26,000 lbs) of potassium permanganate slurry into the fractured bedrock. Permanganate was injected as a slurry to increase oxidant residence time within the bedrock fractures and allow continued reaction with VOCs diffusing from the bedrock matrix. Delivery of the slurry was facilitated through pathways opened by hydraulic fracturing. The fracturing process dilated existing bedrock fractures and flushed fine-grained material from the fractures, thus allowing greater volumes of slurry to enter. Results indicated that the residence time of permanganate in the aquifer exceeded 6 months and achieved significant destruction of VOCs in the source area and in the plume. The radius of influence of slurry injection exceeded 160 ft. Additional information: Technology News & Trends, Dec 2010

SRS Data Report for Lynntech Soil Ozone Treatment Demonstration Adjacent to the 321-M Solvent Storage Tank Pad
K.M. Vangelas, B. Riha, B.B. Looney, W.K. Hyde, J.L. Simmons, and R. Raymond.
WSRC-TR-2000-00255, 29 pp, 2000

The 2000 demonstration of ozone oxidation involved treating a small vadose zone DNAPL plume in the A/M Area over a 29-day period. An active SVE system in this immediate area had achieved decreasing concentrations of DNAPL (PCE and TCE) over a 10-yr period. During ozone injection, the SVE unit removed an estimated 2,390 lbs of PCE. The treatment zone was defined as the vertical distance between 30 ft bgs and 40 ft bgs and a 15 ft radius around the center injector. The estimated pre-test mass of DNAPL in the treatment zone was 319 lbs, and the estimated post-test mass of DNAPL was 24.3 lbs, indicating a 92% destruction rate for the treatment zone. The 295 pounds of DNAPL removed from the treatment zone were either removed through the SVE unit or destroyed by the ozone. Based on the data collected, it was not possible to determine the method, either removal or destruction.

Xpert Design And Diagnostics' (XDD) In Situ Chemical Oxidation Process Using Potassium Permanganate (KMNO₄): Innovative Technology Evaluation Report
U.S. EPA, National Risk Management Research Laboratory.
EPA 540-R-07-005, 96 pp, 2007

ISCO with potassium permanganate was evaluated at the former MEC Building site in Hudson, NH, for treatment of PCE, TCE, cDCE, 1,1,1-TCA, and 1,1-DCA as DNAPL at 23 to 25 ft bgs and as dissolved-phase VOCs in soil and groundwater, primarily from 6 to 25 ft bgs. Three saturated stratigraphic zones, occurring between 6 and 25 feet bgs and within a 1,200 sq ft area, were targeted for ISCO treatment. Although little (320 lb) potassium permanganate could be injected into the shallow, gravelly, sandy zone, 1,500 lbs were injected into the intermediate peat and 1,860 lbs into the deep, silty sand layers. The average soil concentrations of PCE fell by 96% in the peat and 88.5% in the deep layers. The average soil TCE concentrations fell by 92% in the peat and 98% in the deep layers. cDCE showed little change (+1%) in the peat and strong increase (+2,570%) in the deep layers. The average final groundwater concentrations of 746, 612, and 3,090 µg/L PCE, TCE, and cDCE, respectively, fell below the specified remediation performance standards.

Case Studies: PCE

Barb & Ron's Cleaners, Appleton, Wisconsin

ISCO with sodium permanganate was selected for soils contaminated with PCE and breakdown products located beneath a building. Pilot-scale ISCO took place in December 2004, part of the full-scale implementation in April 2005, and the remainder in June 2005. Full-scale implementation was interrupted to allow for permanganate to react. One month post injection, PCE in source area soil had decreased from 4,900 ppm to 2,900 ppm, and source area groundwater fell from 110 ppm to 1 ppm.

Behavior of a Chlorinated Ethene Plume following Source-Area Treatment with Fenton's Reagent
F.H. Chapelle, P.M. Bradley, and C.C. Casey.
Ground Water Monitoring & Remediation, Vol 25 No 2, p 131-141, 2005

Six years of monitoring data show that a plume of chlorinated ethene-contaminated groundwater has contracted significantly following treatment of the contaminant source area with in situ oxidation using Fenton's reagent. Prior to treatment in 1998, concentrations of PCE exceeded 4,500 µg/L in a contaminant source area associated with a municipal landfill in Kings Bay, GA. Vinyl chloride concentrations exceeded 800 µg/L in the plume emanating from the source area. In situ oxidation lowered PCE concentrations in the source area below 100 µg/L, and PCE concentrations have not rebounded above this level since treatment. VC concentrations in the plume fell significantly in the 6-year monitoring period.

Butler Cleaners (#1), Jacksonville, Florida
State Coalition for Remediation of Dry Cleaners, 2000

For cis-1,2-DCE, PCE, TCE, and VC in a treatment area about 10 ft x 40 ft x 30 ft deep, 3 initial injection events of 5,000 gal potassium permanganate were conducted at a concentration of 7.7 g/L per injection event. The process involved 9 well clusters with five monitoring/injection wells (1-in. diameter). Two clusters initially were used as injection wells with other wells converted to injection wells based upon permanganate and contaminant distribution.

Butler Cleaners (#2), Jacksonville, Florida
State Coalition for Remediation of Dry Cleaners, 2001

An initial potassium permanganate pilot test was conducted at this site to address PCE, cis-1,2-DCE, ethylbenzene, toluene, trans-1,2-DCE, TCE, VC, and xylenes. An SVE system installed during the oxidation pilot test was operated from October 1999 to June 2000. In May 2001, co-oxidation was implemented for a second pilot test. The injection fluids were heated to increase the amount of permanganate available for oxidation and injected into one well. Heated potable water (with and without permanganate) for over-flood was injected into two wells. The pilot test also used an SVE system during the injection of heated water to minimize any potential of mobilization of chlorinated VOC vapors in the vadose zone. Tertiary butyl alcohol (TBA) was used as a co-solvent. About 550 gallons of TBA and 450 gallons of water were injected in the lower zone. The concentration of permanganate was approximately 120 g/L water, for a final concentration of ~54 g/L of permanganate in the finished Co-Ox solution. A total of ~450 pounds of permanganate was injected—a maximum theoretical destruction capacity of 236 pounds of PCE. About 8,000 gallons of fluids were extracted following injection. Full-scale implementation began in May 2002. A total of 550 gallons of TBA was injected, a concentration of 55% by volume. Co-Ox fluid was re-circulated and re-injected for approximately 18 hours following initial injection. The Co-Ox solution was left in the aquifer for 12 days before the extraction of ~3,800 gallons of solution and groundwater over a 34-hour period.

Chemical Oxidation of Tetrachloroethene (PCE) Contamination in a Fractured Saprolitic Bedrock Aquifer Using Fenton's Reagent and Sodium Permanganate
P.G. Werner.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

Describes the progressive remediation of a PCE contaminant plume using two separate chemical oxidizers in a fractured saprolitic bedrock aquifer in Rockville, MD. Initial source area remediation with Fenton's reagent-based ISCO was followed by significant rebound. A few months later, 11,000 lbs of liquid sodium permanganate were injected into the aquifer at 50 locations, resulting within one month in an 89.3% average PCE reduction in the aquifer with an average concentration of 909 µg/L.

City Hall (Former Swift Cleaners), Jacksonville Beach, Florida
State Coalition for Remediation of Dry Cleaners, 2007

Two ISCO injections of Fenton's reagent were completed in 2002 to address PCE, TCE, VC, and cis-1,2-DCE at this site. The shallow water table, the conductivity and chemistry of the aquifer, and the accessibility for direct injection of the target area allowed for easy application. Post-injection soil sampling indicated a potential source area, which was excavated and removed in 2004. Concentrations decreased considerably following the 2 injections; however, levels consistent with the baseline-sampling event had rebounded within 2 years, possibly due to residual source material that remained in the unsaturated zone.

CleanOX® In Situ Chemical Oxidation of Groundwater: Fact Sheet
ESTCP, 2006

An ISCO demonstration occurred in a 2,500 sq ft area of Solid Waste Management Unit (SWMU) 45, the location of a former dry cleaning facility at the Marine Corps Recruit Depot, Parris Island, SC. Groundwater PCE concentrations measured immediately before the demonstration exceeded 10 mg/L in some locations. Four injection wells were installed in the impacted area, assuming an injection radius of influence of 15 ft. Six monitoring wells also were installed to aid performance tracking. Treatment consisted of gravity injecting an acidified ferrous sulfate solution (328 gal) over the first 2 days, followed by 8 days of gravity injecting peroxide (3,400 gal, 17.5% by wt.). Groundwater was monitored for routine parameters during chemical application and was sampled for chemical analysis 2 weeks and 6 weeks after treatment. The analytical results did not confirm significant and permanent reduction in chlorinated aliphatic hydrocarbon concentrations in the application area. Potential reasons for this performance include incomplete site characterization, poor chemical distribution within the subsurface, and inadequate mass of injected oxidant.

Fenton-Based Remediation of a Chlorinated Solvent Groundwater Plume Using Segmented Injection Wells: a Field Study
E. Heijn, P. Kakarla, B. Hartsfield, and B. Koenig.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

A Fenton-based chemical oxidation pilot test was performed at a former dry cleaning facility in South Florida to evaluate possible full-scale use of ISCO for a groundwater plume consisting of dissolved-phase PCE, TCE, cis- and trans-1,2-DCE, and VC. Six injection wells were installed in the apparent source area, spaced no more than 15 ft from one another to achieve overlapping radial influences. Each 4-inch-diameter PVC injection well was screened from 6 to 30 feet bgs, with 2-foot-thick bentonite seals constructed in the annular space to create separate screened intervals at 6 to 12 ft, 14 to 20 ft, and 22 to 30 ft. The segmented well allows the use of a specially-designed injector, equipped with K-packers that coincide exactly with the bentonite seals, to direct chemical oxidant to a specific depth interval. Two injection events 6 weeks apart reduced contaminant levels overall by 63%, with PCE and TCE concentrations reduced by 95 and 97%, respectively.

In Situ Chemical Oxidation at Six Drycleaner Sites, Various Locations
Federal Remediation Technologies Roundtable Cost & Performance Database, 2001, 2002

ISCO was conducted at six sites—Butler Cleaners #1 and #2, Former Quick-N-Easy Wash-O-Mat, Former Artistic Cleaners, Hanner's Cleaners, Swift Cleaners, and Paul's classic—contaminated with chlorinated solvents from drycleaning operations, primarily TCE and PCE contamination in groundwater. Solutions of potassium permanganate were injected into the subsurface at 3 sites, hydrogen peroxide and catalyst were injected at 2 sites, and an ozone in-well air sparging system was installed at 1 site. Only Swift Cleaners reporting achieving remediation goals. Other sites reported that contaminant concentrations were not significantly reduced or that cleanup goals were not met.

In Situ Chemical Oxidation at Two Drycleaner Sites, Hutchinson, Kansas and Jacksonville, Florida (2003)
Federal Remediation Technologies Roundtable Cost & Performance Database, 2003

Full-scale ISCO was conducted at Ineeda Cleaners and Swift Cleaners to address groundwater contaminated with TCE and PCE. PCE ranged from 4,400 to 10,000 µg/L and TCE from 24 to 382 µg/L. Reported plume areas ranged from 300,00 sq ft to 12,000,000 sq ft, and reported plume depths ranged from 50 to 56 bgs. At Ineeda Cleaners, ozone was injected into the subsurface, and at Swift Cleaners, hydrogen peroxide and catalyst (Fenton's chemistry) were injected into the subsurface. After up to 3 rounds of injection, the cleanup goal of EPA MCLs was not met at either site. At Ineeda Cleaners, this was attributed to problems with the KVA C-Sparger wells. At Swift Cleaners, rebound concentrations of PCE were observed, and 3 additional phases proceeding downgradient will be conducted at this site. 2007 Update of ISCO at Swift Cleaners

In Situ Chemical Oxidation of a Perchloroethene Source Area Using Potassium Permanganate
M.J. Salvetti, B.R. Nwokike, and W.A. Murray.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

A 5-month pilot-scale application of potassium permanganate to a PCE source area at the Naval Training Center in Orlando, FL, oxidized residual PCE and dramatically reduced PCE concentrations in groundwater. About two-thirds of the 80-ft by 200-ft by 30-ft-deep source area is located beneath a former laundry building. Three groundwater extraction/injection well pairs were used to create a 65-foot-long recirculation cell. Groundwater was extracted, dosed with permanganate, retained in mixing tanks to allow the PCE in the extracted groundwater to oxidize, and then injected. PCE concentrations were reduced from concentrations as high as 24,300 µg/L to concentrations near or below MCLs.

In Situ Chemical Oxidation Using Fenton's Reagent at Naval Submarine Base Kings Bay, Site 11, Camden County, Georgia
Federal Remediation Technologies Roundtable Cost & Performance Database, 2000

Site investigations found the groundwater in the Site 11 area to be contaminated with PCE as well as its breakdown products (TCE, DCE, and VC). The Navy selected the Geo-Cleanse process (ISCO using Fenton's reagent) to reduce groundwater contaminant concentrations in the source area, followed by natural attenuation to address residual contamination. For Phase 1, a total of 12,045 gallons of solution was applied through 23 injectors in two injection events. During Phase 2, the system was expanded to add 21 injectors, and a total of 11,247 gallons was applied in two injections of Fenton's reagent. Subsequently, total contaminant concentrations decreased to below the cleanup goal of 100 µg/L in all but one well with unacceptable DCE levels located downgradient of the area of concern. In August 1999, elevated concentration levels were found in an injector located to the east of the area of concern, indicating the presence of an additional contamination source area in the shallow soil. The soil in this area has been excavated and the Navy plans to use ISCO to polish the groundwater. Additional information.

In Situ Chemical Oxidation Using Hydrogen Peroxide at Four Dry Cleaner Sites
Federal Remediation Technologies Roundtable Cost & Performance Database, 2005

ISCO was conducted at 4 dry cleaner sites contaminated primarily with PCE and its breakdown products (TCE, DCE, and VC). At Daisy Fresh, ISOTEC's chemical oxidation process was used to address TCE, PCE, DCE, VC, chloroform, and other organics. At the former Alpine Cleaners, an aqueous solution of ferrous sulfate and hydrochloric acid was injected initially in 1999, followed by hydrochloric acid, and a 35% solution of hydrogen peroxide. In August and September of 2001, 135 gallons of a 5.5% solution of potassium permanganate were injected at the site. At the Park Avenue Cleaners, a biodegradable surfactant and 310 gallons of a proprietary catalyst solution were injected at each injection point, as well as a mixture of a proprietary acid and a hydrogen peroxide solution. At the Spin City Cleaners, a biodegradable surfactant and 116 gallons of a proprietary catalyst solution were injected at each point, plus a mixture of a proprietary acid and a hydrogen peroxide solution. Contaminant concentrations at all four sites were reduced following treatment, with percentage reduction ranging from 33 to 100%. At the Daisy Fresh site, concentrations of VOCs decreased at first and then increased in two wells, which was attributed to the desorption of solvents from the soil. Cost data were not provided for any of the projects.

In-Situ Duox™ Chemical Oxidation Technology to Treat Chlorinated Organics at the Roosevelt Mills Site, Vernon, CT: Site Characterization and Treatability Study Report
U.S. EPA, Superfund Innovative Technology Evaluation Program.
EPA 540-R-05-008, 45 pp, 2005

The DUOX technology utilizes a combination of potassium permanganate and sodium persulfate to destroy unsaturated chlorinated solvents. Material from a source area of pure-phase PCE existing as distinct globules beneath the Roosevelt Mills building in the upper 1-3 ft of the foundation fill material was subjected to a treatability test. The 2 oxidants were applied separately, in sequence, and in combination. Permanganate, alone and in combination with persulfate, successfully reduced the PCE-contaminated groundwater from a starting concentration of ~130 µg/L to less than 5 µg/L over the 120-hour test, but persulfate alone did not reduce the PCE to less than 5 µg/L. Owing to the lack of significant soil oxidant demand at this site, the treatability study at Roosevelt Mills was not able to demonstrate fully the potential of the DUOX technology. Other sites having significant soil oxidant demand might benefit from a DUOX approach.

OU III Building 96, Recommendation for Source Area Remediation
Holzmacher, J.R. and Brookhaven National Laboratory, 28 pp, 2009

In 2005, an initial round of potassium permanganate was injected to address a PCE groundwater source area at Building 96 (AOC 26B) at Brookhaven National Laboratory (BNL). Following two additional injections, one performed in 2005 and one in 2006, monitoring data indicated that PCE concentrations were rebounding to pre-injection levels. In 2007, Cr(VI) was detected in well influent at concentrations up to 124 µg/L, and elevated levels of Cr(VI) were detected immediately downgradient of the source area, correlating to areas treated with permanganate. Manganese oxide is a byproduct of the potassium permanganate treatment process, which oxidizes Cr(III) to Cr(VI). In 2008, additional soil characterization identified a discrete area of PCE soil contamination 25 x 25 ft in the unsaturated zone from just below the surface to a depth of 15 feet bgs and not below the water table. PCE soil concentrations reached a maximum of 1,800,000 µg/kg. The unsaturated zone was also characterized by interbedded thin silt layers. These findings explained the lack of success of the permanganate injections. BNL recommended optimization of the Building 96 remedy through the excavation of contaminated soil (~350 cubic yds) with off-site disposal. [Additional note: BNL published an Explanation of Significant Differences in July 2009, and the New York DEC and EPA agreed to the excavation remedy in August 2009.]

Pilot-Scale Demonstration of In Situ Chemical Oxidation Involving Chlorinated Volatile Organic Compounds: Design and Deployment Guidelines, Parris Island, SC, Marine Corps Recruit Depot, Site 45 Pilot Study
Huling, S.G., B.E. Pivetz, K. Jewell, and S. Ko.
EPA 600-R-16-383, 176 pp, 2016

A portable, low-cost, direct-push injection system was designed, constructed, and deployed at Site 45 to address PCE and daughter products via pilot-scale ISCO using sodium permanganate. After three injection events, significant reductions were observed in post-oxidation CVOC concentrations in groundwater and soil, and a 92% and 76% reduction in total CVOC mass flux in shallow and deep micro-wells, respectively. CVOC rebound was determined in 3 of the 38 wells, and post-oxidation PCE concentrations in one well indicated the presence of DNAPL. Results of this study are intended to provide details and guidelines for use by EPA and DoD remedial project managers planning ISCO remediation at other sites.

Technical and Regulatory Guidance for In Situ Chemical Oxidation of Contaminated Soil and Groundwater
Interstate Technology & Regulatory Council (ITRC). ISCO-1, 67 pp, 2001

Although this guidance has been superseded, Appendix B contains 8 case studies of ISCO implementation, 6 of them (dry cleaners, a manufactured gas plant, and a wood treatment facility) at DNAPL-contaminated sites. Only the wood treater case study is replicated in the 2005 guidance.

Use of In Situ Chemical Oxidation with Permanganate in PCE-Contaminated Clayey Till with Sand Lenses
Jirij Hønning Technical University of Denmark, Ph.D Thesis, 76 pp, 2007

This thesis discusses the interaction of permanganate with sedimentary reductants and suggests that that the chemical oxygen demand of the sediments themselves are an important factor in planning a remedial action.

Case Studies: TCE

Comparison of EHC, EOS, and Solid Potassium Permanganate Pilot Studies for Reducing Residual TCE Contaminant Mass
Marks, C.
E2S2: Environment, Energy Security and Sustainability Symposium and Exhibition, 9-12 May 2011, New Orleans, Louisiana. Presentation 12621, 30 slides, 2011

At the Defense Distribution Depot San Joaquin-Sharpe (DDJC-Sharpe) site, Lathrop, CA, three treatment technologies were evaluated for their potential to increase TCE mass removal in the saturated zone. Introduction of emulsified oil (EOS) in the North Balloon began in April 2008, injection of solid potassium permanganate in the South Balloon began in May 2008, and injection of a redox compound (EHC, complex organic carbon plus ZVI) in the Central Area began in August 2008. Where the amendment was able to contact the contaminant, all three amendments reduced TCE concentrations to <5 ug/L (the cleanup level). All three amendments continued to distribute/diffuse horizontally after injection and had secondary water quality impacts. Solid potassium permanganate was selected as the preferred amendment because it distributed/diffused significantly more in fine-grained soils than the other two amendments, destroyed TCE more quickly without formation of daughter products, and was cost effective because multiple injections were not necessary. The pilot study results also showed that hydraulic fracturing increased the distribution of the amendment in fine-grained soils when compared to gravity-fed injection wells. Additional information: Longer Abstract; DDJC-Sharpe 2009 5-Year Review

Demonstration of ISCO Treatment of a DNAPL Source Zone at Launch Complex 34 in Cape Canaveral Air Station: Final Innovative Technology Evaluation Report
A. Gavaskar and Y. Woon-Sang.
Interagency DNAPL Consortium, 117 pp, 2002

At least half (49 to 84%) of the initial total TCE mass and possibly 76% of the DNAPL mass in the source zone were removed by ISCO using permanganate. Much of this removal can be attributed to destruction of TCE by oxidation, as indicated by the chloride buildup in the plot. The sharp increase in carbon dioxide and, consequently, alkalinity levels in the groundwater, is another sign of considerable oxidation of TCE and natural organic matter occurring in the aquifer. Post-demonstration sampling indicated that the levels of breakdown products (cis-1,2-DCE and VC) in many parts of the plot declined considerably as well. Some rebound in concentrations was evident 9 months after the demonstration, after re-equilibration occurred between the remaining DNAPL and dissolved TCE concentrations, but the rebound levels were still considerably below the pre-demonstration levels.

Destruction of TCE DNAPL Using KMnO₄: Delivery with Direct-Push Technology and Distribution Under Density Driven Advection and Diffusion
C.S. Bourne, B.L. Parker, and J.A. Cherry.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

A potassium permanganate solution was delivered to the DNAPL zone inside a sheet pile enclosure over a 2-day period using moderate pressures and flow rates. The results of this field trial demonstrated the effectiveness of the inject-and-leave approach for distribution of permanganate solution along a DNAPL pool. The approach relied on density-driven advection and diffusion. A single injection of 4,000 liters achieved a permanganate spread of 12 to 15 ft after 2 weeks with minimal additional spreading in a zone where TCE was consuming permanganate as it spread across the top of the DNAPL layer. Manganese oxide observed in cores collected 7 weeks after injection and high chloride concentrations (>5,000 mg/L) confirm the large consumption of TCE. Complete TCE destruction was accomplished in local zones, while thicker DNAPL zones would require additional loading of permanganate solution to achieve complete destruction.

EPA Superfund Record of Decision: Newton County Wells, OU 01, Joplin, MO
Missouri Department of Natural Resources, Jefferson City, MO.
EPA ROD-R07-04-655, 102 pp, 2004

A Removal Action required under the 1998 Consent Decree began in 2002 to address the principal waste threat. The contractor used ISCO with potassium permanganate to destroy the TCE DNAPL present in a pipeline trench, injecting ~35,000 gallons of 3% potassium permanganate solution. The contractor conducted monitoring over an extended period of time to determine the complete removal of the contaminant source. ISCO was limited to the pipeline trench area, where nearly 20 gallons of DNAPL was destroyed. About 4 gallons of TCE remain distributed in the overburden soils, the uppermost groundwater, and the Mississippian Aquifer site area.

A Full-Scale Demonstration of In Situ Chemical Oxidation through Recirculation at the X-701B Site
O.R. West, et al.
ORNL/TM-13556, 110 pp, 1997

In 1997, the Department of Energy undertook a month-long, field-scale treatability study using in situ chemical oxidation through recirculation (ISCOR) technology at a Portsmouth Gaseous Diffusion Plant site where TCE contaminates groundwater and sediments.

In Situ Chemical Oxidation Geo-Cleanse Process at the Naval Air Station Pensacola Florida, Operable Unit 10, Pensacola, Florida
Federal Remediation Technologies Roundtable Cost & Performance Database, 2000

The Geo-Cleanse process used Fenton's reagent (hydrogen peroxide (50%) and an equivalent volume of ferrous iron catalyst) and was conducted in two phases. Phase I injected 4,089 gallons of hydrogen peroxide and similar volumes of reagents through 14 injection wells at a depth of 10 to 40 ft bgs. Phase 2 injected 6,038 gallons of hydrogen peroxide and similar volumes of reagent through 10 injection wells, totaling 10,127 gallons; phosphoric acid was added to the reagent mix to stabilize the hydrogen peroxide. Over the two phases, the concentration of TCE fell from 3,600 µg/L to <5 µg/L, as measured in a source area monitoring well. Elevated concentrations of ferrous iron in the groundwater, due to a historic sulfuric acid spill, limited the effectiveness of the first phase of injections. In Phase 2, phosphoric acid was added to the reagent mix to help stabilize the hydrogen peroxide in the presence of elevated ferrous iron concentrations. The actual costs for the demonstration were $178,338, and additional injections were not planned for this site.

In Situ Chemical Oxidation Through Lance Permeation at the Portsmouth Gaseous Diffusion Plant (PORTS)
M.Z. Martin and O.R. West.
ORNL/TM-2002/272, 37 pp, 2002

Sodium permanganate was delivered to the subsurface using vertical lance-like injectors deployed at relatively close spacing in TCE-contaminated sediments in a field demonstration conducted in July-August 2000 at DOE's Portsmouth Gaseous Diffusion Plant. The demonstration was not completed due to an accident that caused a worker serious injuries. Although the performance assessment data are limited, the study highlights important health and safety issues that must be considered when implementing ISCO.

In Situ Chemical Oxidation Using Fenton's Reagent at Naval Air Station Pensacola, Florida
Federal Remediation Technologies Roundtable Cost & Performance Database, 2001

ISCO using Fenton's reagent involved pressurized injection of concentrated hydrogen peroxide and ferrous iron catalyst to oxidize TCE and its breakdown products in groundwater. In the first phase, a total of 4,089 gallons of 50% hydrogen peroxide and a similar volume of ferrous iron catalyst was injected into the former sludge drying bed over 5 days in December 1998. In the second phase, 6,038 gallons of 50% hydrogen peroxide and a similar volume of catalyst, along with phosphoric acid, were injected over 6 days in May 1999. Pump and treat had been ongoing at the site since February 1987. In 1995, a data review showed that contamination was limited to one monitoring well at an intermediate depth. The number of recovery wells was reduced from 7 to 3, and as of 2000, the Florida DEP was allowing pump and treat to be discontinued and monitored natural attenuation to be implemented.

In Situ Chemical Oxidation Using Potassium Permanganate: Innovative Technology Summary Report
U.S. DOE. DOE/EM-0496, 35 pp, 1999

ISCO was used in a demonstration project to treat TCE present as DNAPL and as a dissolved-phase plume at the X-701B facility at the Portsmouth Gaseous Diffusion Plant in the spring of 1997. Horizontal recirculation wells were used and the oxidant reduced TCE significantly in some areas, but resistivity data indicated nonuniform progression of the permanganate during the demonstration, likely due to heterogeneities in the aquifer,

Permanganate In-Situ Chemical Oxidation of TCE in a Fractured Bedrock Aquifer
D. Bryant, T. Battey, K. Coleman, D. Mullen, and R. Wood.
International Containment & Remediation Technology Conference & Exhibition, 10-13 June 2001, Orlando, Florida.

An ISCO treatability study was conducted in a bedrock aquifer at Site N7, NASA Dryden Flight Research Center, Edwards Air Force Base. In an area 100 ft by 50 ft by 100 ft deep, 7,450 gallons of 1.8% potassium permanganate solution were injected serially into 8 screened wells and 2 boreholes over 5 days. TCE and cDCE remained non-detectable (reduced from 6,500 µg/L and 710 µg/L, respectively) for 60 days after injection in the treatment zone. Temporary acetone and metals increases observed in groundwater following treatment attenuated rapidly. Only chromium and nickel remained elevated 60 days after treatment, though neither is stable in alkaline aquifers and is expected to attenuate as the permanganate degrades. The purple color imparted to groundwater by permanganate will persist as long as permanganate concentrations remain >0.5 mg/L, ~283 days based upon permanganate degradation measurements. The treatment appeared to offer a viable remedial alternative for chlorinated solvents dissolved in the fractured bedrock aquifer at Edwards AFB.

Status Report on Remedy Effectiveness: Hookston Station, Pleasant Hill, California
California Regional Water Quality Control Board, San Francisco Bay Region. 142 pp, 2017

To address impacts associated with the presence of TCE and daughter products, five ISCO injection events were implemented between 2008 and 2010 to remediate B-Zone groundwater. Performance monitoring showed successful distribution of potassium permanganate throughout the targeted treatment area. VOC concentrations within the core of the on-site source area are lower than pre-remediation results by up to two orders of magnitude. No additional ISCO treatment is needed. Since installation in 2009 of a ZVI PRB to remediate A-Zone groundwater, TCE concentrations declined significantly. Only a handful of wells remain above the cleanup standards, and CVOC concentration trends in soil vapor are decreasing. Additional information: CRWQCB Project Page

Abstracts of Journal Articles

A Case Study on Enhanced Reductive Dechlorination Resulting from a Chemical Oxidation Pilot Test