This page provides links to case studies of ISCO applications, beginning with resources in which multiple case studies have been compiled. The next section lists projects in which treatment was achieved using combinations of oxidants, and it is followed by sections broadly organized by oxidant type: hydrogen peroxide (including catalyzed hydrogen peroxide), ozone, permanganates, and persulfate.

Case Study Compilations

Chemical Oxidation Site Profiles

Information about completed and ongoing applications of in situ chemical oxidation technologies to treat chlorinated solvents, petroleum products, and pesticide compounds in groundwater and soil are captured in this web site. The information is provided in project profiles that summarize relevant site information, contaminants and media, technology design and operation, and cost and performance results, as well as point(s) of contact and references.

Code of Good Practice: In Situ Chemical Oxidation
Ceulemans, P. and V. Labeeuw.
CityChlor, 112 pp, 2013

This code of good practice from the EU's CityChlor project provides an overview of the current theoretical knowledge of ISCO in Section 1. To help environmental practitioners decide whether ISCO is an appropriate soil remediation technique for a particular site, Section 2 offers six example case studies: three case studies of ISCO with activated sulfate, with ozone, and with permanganate and hydrogen peroxide, followed by three more case studies of ISCO with hydrogen peroxide alone.

Critical Analysis of The Field-Scale Application of In Situ Chemical Oxidation for the Remediation of Contaminated Groundwater
Krembs, Friedrich J., Master's thesis, Colorado School of Mines, 226 pp, 2008 [supported by SERDP/ESTCP]

This thesis creates a database from 242 ISCO sites. The thesis analyzes trends for the sites and allows for interactive activity with the user.

Federal Remediation Technologies Roundtable Cost and Performance Case Studies

• In Situ Treatment at Three Dry Cleaner Sites, Various Locations (2004)
  [ozone (1) and modified Fenton's reagent (2)]
• In Situ Chemical Oxidation at Two Drycleaner Sites, Hutchinson, Kansas and Jacksonville, Florida (2003)
  [ozone (1) and hydrogen peroxide (1)]
• In Situ Chemical Oxidation at Six Drycleaner Sites, Various Locations (2001, 2002)
  [permanganate (3), peroxide (2), ozone (1)]

Field Applications of In Situ Remediation Technologies: Chemical Oxidation
EPA 542-R-98-008, 1998

Describes pilot demonstrations and full-scale applications that either treat soil and ground water in place or increase the solubility and mobility of contaminants to improve their removal by other remediation technologies.

In Situ Chemical Oxidation: Lessons Learned From Multiple Sites
Pac, T.J., J. Baldock, B. Brodie, J. Byrd, B. Gil, K.A. Morris, D. Nelson, J. Parikh, et al.
Remediation 29(2):75-91(2019)

This paper compiles a detailed set of in situ chemical oxidation (ISCO) lessons learned pertaining to design, execution, and safety based on global experiences over the last 20 years. While the benefits of a correct application are known, history also provides examples of a variety of incorrect applications that provide an opportunity to highlight recurring themes that resulted in failures. This paper combines a thorough discussion of lessons learned through decades of ISCO implementation throughout all aspects of ISCO projects with an analysis of changes to the ISCO remediation market. By discussing the interplay of these two themes and providing recommendations from collective lessons learned, the future of safe, cost-effective, and successful applications of ISCO can be improved.

The DNAPL Remediation Challenge: Is There a Case for Source Depletion?
EPA 600-R-03-143, 2003

The Bachman Road and Sages sites, summarized in Appendix A, are examples of removing substantial amounts of DNAPL, with subsequent changes to the geochemical environment that enhance biodegradation of the remaining mass of DNAPL. These technologies are not likely to be effective at removing DNAPL present in low permeability source zones, such as fractured systems. At the time this report was written, neither field-scale demonstrations nor full-scale applications of in situ flushing were known to have achieved site closure at a DNAPL source zone.

Combinations of Oxidants

Chemical Oxidation Using Ozone, Hydrogen Peroxide, and Air Injection Systems for Aggressive Remediation of BTEX, MTBE, and TBA
C.B. Whisman.
White paper, 6 pp, 2006

This paper presents two case studies of projects to address BTEX, MTBE, and TBA impact in soil and groundwater (including separate-phase hydrocarbons): 1) ozone and hydrogen peroxide injection using a PulseOx system at an active gasoline service station site, and 2) hydrogen peroxide and air injection using a HypeAir system at an inactive service station site. These aggressive chemical oxidation techniques have been used to remediate BTEX- and MTBE-contaminated soil and groundwater through monthly and short-term (daily/weekly) events at relatively low life-cycle remediation costs ($15,000 to $200,000) in varying lithologies and within different regulatory environments.

Decontamination of Dense Nonaqueous-Phase Liquids in Groundwater Using Pump-and-Treat and In Situ Chemical Oxidation Processes: A Field Test
Xie, T., Z. Dang, J. Zhang, Q. Zhang, R.-H. Zhang, C.-J. Liao, and G.-N. Lu.
RSC Advances, 11:4237-4246(2021)

This field study combined pump-and-treat (P&T) and in situ chemical oxidation (ISCO) to remove DNAPLs from groundwater. Underground water pH, electrical conductivity, dissolved oxygen concentration, and SO₄^2- concentration provided indirect evidence of in situ chemical reactions. The P&T-ISCO process, which used 1.5% sodium persulfate and 0.03% sodium hydroxide, had a remarkable effect on DNAPLs. DNAPL diffusion distance was much higher under pumping conditions than under natural conditions. Pollutant concentration positively correlated with the pH, electrical conductivity, and dissolved oxygen concentration and negatively correlated with the SO₄^2- concentration during remediation.

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.

Expediting Cleanup of a Pump and Treat Site by Use of Chemical Oxidation Technology
G. Cronk and L. Stevens.
Sixth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 19-22, 2008. Battelle Press, Columbus, OH. 11 pp, 2008

At the U.S. Gypsum Company site in La Mirada, CA, a pump-and-treat system has operated for over 10 years (1996 to 2006), successfully reducing the size of two co-mingled contaminant plumes, one with benzene and one with dissolved-phase TCE. To expedite this cleanup, two ISCO technologies were implemented. For the TCE plume, a pilot test using potassium permanganate achieved TCE reductions ranging from 85 to 100% in 120 days, and a full-scale permanganate treatment is planned to address the remaining TCE plume. For the benzene plume, injections of catalyzed hydrogen peroxide and activated sodium persulfate resulted in a reduction in benzene concentrations from a pre-ISCO maximum of 5,500 µg/L to 98 µg/L, a 98% reduction. Other wells have shown benzene reductions from 96 to 99.9%.

In Situ Chemical Oxidation Pilot Test: Design Criteria and Results for Ozone and Hydrogen Peroxide Injection
Pavlik, J.D. and J.P. Gwinn.
The First International Conference on Challenges in Site Remediation, Chicago, Illinois, 23-27 October 2005. 8 pp, 2005

A pilot text was designed and conducted to test ISCO effectiveness, collect design data for full-scale implementation, and develop protocols for future pilot tests for multiple sites affected by total petroleum hydrocarbons, including BTEX, MTBE, and TBA. Originally planned for 8 weeks, the pilot was continued for an additional 4 weeks because TPHg, BTEX, and MTBE concentrations were reduced significantly. By the end of the pilot test, DO exceeded 20 mg/L within a 15-ft radius of the injection points. TPHg and benzene concentrations fell by 2 to 3 orders of magnitude and MTBE concentrations by 1 to 2 orders of magnitude. Additionally, if a pronounced smear zone is present, remediation effectiveness can be increased by (1) injecting peroxide into the capillary fringe, (2) operating the injection system to provide controlled fluctuations of the water table, or (3) operating the system during periods of seasonally high water levels.

In Situ Chemical Oxidation in Clays Using Hydraulic Fracturing
Bures, G.H., T.J. Williams, E. Mance, and C. Clark.
Proceedings of the Seventh International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2010). Battelle Press, ISBN: 978-0-9819730-2-9, Paper & presentation D-085, 8 pp & 21 slides, 2010

A soil fracturing program was conducted at a former dry cleaning facility to mitigate PCE and its daughter products to risk-based soil and groundwater remediation criteria by enhancing the zone of influence of peroxidants injected through permeable sand fractures in the clay subsoil. Following two unsatisfactory applications of modified Fenton's reagent into the fracture network (32% PCE decrease on average), potassium permanganate slurry was injected into the fracture network on six occasions during 2007, followed by 12 injections of sodium permanganate in 2008 and 2009. Sampling results as of August 27, 2009, indicated that PCE concentrations had decreased on average by 95% in wells inside the perimeter of the plume and 78% in wells centered in the core of the plume. With a general decrease in soil PCE concentrations, the quantity of soil classified as hazardous fell by ~62% across the site. Ongoing peroxidant injections are anticipated to destroy chlorinated constituents that leach from core area clays into the fracture network.

In-Situ DUOX^TM 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 Site Evaluation (SITE) Program, Washington, DC.
EPA 540-R-05-008, 45 pp, 2005.

The DUOX™ technology uses a combination of persulfate and permanganate to destroy unsaturated chlorinated solvents. The major benefit of the process, as compared to single-phase oxidation technologies, is in the treatment of impacted media with significant soil oxidant demand. Because the media evaluated during this study did not exhibit significant soil oxidant demand, the full utility of the process was not demonstrated.

In-Situ Remediation of Dissolved Metals Plume — From Concept to Full-Scale Remediation
Beveridge, M. | REMTECH 2021: The Remediation Technologies Symposium, Banff, AB, Canada, 13-15 October, 19 slides, 2021 [Abstract]

An innovative approach using injected ferrous iron followed by in situ oxidation to precipitate hydrous ferric oxide (HFO) was developed to remediate an inaccessible dissolved metals plume at a commercial property discharging to an adjacent freshwater aquatic receptor. HFO successfully decreased dissolved metals concentrations via coprecipitation and/or adsorption in the aquifer. Preliminary post-injection groundwater sample results indicate up to a 98% decrease in dissolved metal concentrations compared to baseline. Phases of work included assessing and delineating the plume, geochemical modeling, bench scale testing, and pilot testing, followed by full-scale implementation. The technology is adaptable to a wide range of site conditions, limitations, and constraints and can remediate a wide suite of common metal contaminants, including As, Cu, Cd, Cr, Pb, Ni, and Zn. Additional information: Slides

Investigative Area 12 Operable Unit-2 Interim Remedial Measure Progress Report Hoffmann-La Roche Inc. Site, 340 Kingsland Street, Nutley, New Jersey
Hoffmann-La Roche Inc., 21 pp, 2019

Operable unit (OU) 2 of the Hoffman-La Roche Inc. site was contaminated with >1,000 to <10,000 µg/L PCE and its degradation products (PCE+) in groundwater to a depth of approximately 50 ft below ground surface. A successful pilot study from October 2014-January 2015 evaluated the effectiveness of and established design parameters for treating PCE+ in groundwater using in-well air stripping (IWAS) enhanced with in situ chemical oxidation (ISCO). A full-scale system that encompassed ~46,000 ft² in the central portion of IA-12 was subsequently installed as an interim remedial measure. (IRM) Three separate treatment systems operated from July 2016 through 2017. Seventy-eight ISCO wells injected ozone in all areas and supplemental activated sodium persulfate was injected in one area. Twenty-five IWAS wells and 16 vapor extraction trenches along the perimeter of the main injection treatment areas were installed to promote additional vapor recovery and capture sparged gases. Groundwater sampling results through October 2018 showed a significant overall reduction in PCE+ concentrations. An overall 69% reduction in PCE+ concentrations was achieved at system shutoff in December 2017. Only minor rebound/recontamination was observed with an overall 55% reduction in PCE+ concentrations was attained 10 months after cessation of IRM.

Low Carb ISCO Site Remediation Using I-SAV© Technology
Dannwolf ǀ AquaConSoil 2021, 15-17 June, virtual, abstract only, 2021

ISCO using i-SAV© technology was pilot-tested to remediate remaining PCE/TCE contamination at a site following six years of operating a pump and treat system. A total of 2.53 t of Na₂S₂O₈, persulfate (PS) and permanganate (PM) were injected using a direct push system in one borehole. Spatial monitoring of the artificially-generated fractures was conducted using tiltmeters. Measurements of the groundwater potential at three groundwater monitoring wells located around the injection borehole indicated that existing fissures were (re)activated and filled with reagents. A total of 25 fractures were generated, increasing the permeability of the affected area and local groundwater flow and influencing the distribution of the emplaced reagent. At least 25% of the injected PM was available in the subsoil two months after the injection. Gas generation in the monitoring wells showed that PS and/or PM were active 15 months after injection. Remediation goals in the test area were met after ~2 years of monitoring. The CO₂ footprint for the remediation of 163 kg CHC was calculated, including and excluding the PM production. During i-SAV remediation, 15.3 kg CO₂/kg CHC were produced, and 88 kg CO₂ /kg CHC were generated when the CO₂ produced during the manufacturing process of the PM was included in the calculation. The CO₂ footprint of the i-SAV remediation technology is low compared to other remediation technologies, and the overall footprint depends on the CO₂ produced during the manufacturing process of the remediation reagent.

Pilot Field Evaluation and Laboratory Development of Controlled Release Technologies for Groundwater Remediation
Carpenter, A., J. Darcy, D. Meyer, J. Haselow, M. Haselow, and W. Storm.
29th Annual David S. Snipes/Clemson Hydrogeology Symposium, 21 October, Clemson, SC, 22 minutes, 2021

Lab and pilot field deployment of RemRx™ Controlled Release Polymer (CRP) permanganate and persulfate formulations designed to mitigate contaminant rebounding were conducted at two sites. The first site is a PCE-impacted municipal site where injection-based ISCO was not permitted due to issues with daylighting. CRP Permanganate pellets were packed into slotted canisters and suspended in existing monitoring wells. Permanganate release was sustained for >1 yr after deployment and created a radius of influence between 1-7 ft in the tight clay area. At the second site, CRPs were deployed following the excavation of impacted soil at a former gas station where elevated BTEX levels in groundwater remained after UST removal. A >90% decrease in BTEX concentrations was observed in the CRP placement area. Persulfate levels remained elevated up to 1 year after deployment and were measured up to 30 ft down gradient, indicating the CRPs achieved sustained release, and release mechanisms effectively treated downgradient areas. Sulfate and an increase in oxidation-reduction potentials were detected >30 ft downgradient of CRP placement, indicating that decreases in contaminant concentration can be attributed to persulfate oxidation. Site considerations to guide future deployments of CRP. The presentation also discusses preliminary lab studies demonstrating the use of the controlled release matrices to harness the oxidative potential of percarbonate. Considerations for using RemRx CRP percarbonate for pilot field testing are also presented.

Remediating Contaminated Groundwater with an Aerated, Direct-Push, Oxidant Delivery System
Reece, J., M. Christenson, A. Kambhu, Y. Li, C.E. Harris, and S. Comfort.
Water 12:3383(2020)

A novel aerated, slow-release, oxidant delivery system continuously bubbled air beneath a slow-release oxidant in situ to create an airlift pump. The pump disperses water and oxidant from the top of the outer screen and draws it in at the bottom, creating a continuous circulation pattern around each drive point. This facilitates the spreading of the oxidant as it slowly dissolves from the wax matrix. Given that the aeration rate controls the outward flow of oxidant from the outer screen in all directions, the radius of influence around each drive point is largely a function of the outward velocity of the oxidant exiting the screen and the advection rate opposing the upgradient and lateral spreading. Results from temporal sampling from three field sites treated with the aerated oxidant system show that contaminant concentrations typically decreased 50-99% within 6-9 months after installation. Supporting flow tank experiments that demonstrate oxidant flow patterns and treatment efficacy are also presented.

Revised Work Plan and Trial Management Plan: Surfactant Enhanced In Situ Chemical Oxidation (S-ISCO®) & Surfactant Enhanced Product Recovery (SEPR™), Block 5 and Hickson Road, Barangaroo, Pilot Trial
New South Wales Office of Environment and Heritage, Australia. 355 pp, 2011

From 1840 to 1921, sections of the Barangaroo site were used to manufacture gas. Portions of the contaminated former gas works infrastructure remain in place beneath the current slab surface and adjacent roadway. This work plan describes the contaminated areas, explains in detail the workings of the innovative SEPR™ and S-ISCO® technologies, provides design information for the pilot test and the injection and SVE systems, and discusses performance measures and the monitoring, health and safety, and waste management plans. S-ISCO® is designed to solubilize contaminants rather than mobilize them. The co-eluted surfactant/co-solvent and oxidant fronts move through the subsurface together and solubilization and oxidation occur simultaneously, such that the contaminants (i.e., TPH, BTEX, PAHs, coal tar) are destroyed in place. The system incorporates water, activator (Fe-TAML and/or sodium hydroxide), VeruSOL® surfactant, and oxidant (hydrogen peroxide and/or sodium persulfate).

Western Sector In-Situ Chemical Oxidation Project: Additional Injection Pilot Testing Supplemental Results
McFalls, S. and S.A. Goodlove. Savannah River National Lab, SRNS-STI-2020-00048, 77 pp, 2021

ISCO was employed to remove VOCs and a recovery well was installed to contain a high-concentration VOC groundwater plume in the Western Sector of the M-Area Hazardous Waste Management Facility (HWMF). DNAPLs migrated from the M-Area Settling Basin along geologic strata resulted in a high TCE and PCE-concentration groundwater plume in the Western Sector. Pump-and-treat has hydraulically controlled the primary plume sources in addition to soil vapor extraction, dynamic underground stripping, groundwater recirculation wells, and bioremediation. The ISCO project utilized the gradient induced by the recovery well to plan injection and monitoring locations. Combining ISCO and the recovery well helped control the plume and maximize remediation efforts. An initial round of sodium persulfate and potassium permanganate injections was performed in 8 injection wells with 4.6-m screen zones. Dual oxidant treatment effectively destroyed chlorinated ethenes in the treatment area, oxidants were not well distributed vertically across all aquifer horizons, and the injections had little impact on the upper portion of each geologic horizon. The injection strategy was refined to address this limitation in a second round of injections that included new injections wells with shorter screens to better target specific zones of the treatment area. An injection scheme similar to the first round was employed using different oxidant volumes. The activity will help further assess the viability of full-scale remediation using ISCO to treat PCE, TCE, and daughter products present in M-area groundwater. Additional information: Supplemental Results

Hydrogen Peroxide

A New Foam-Based Method for the (Bio)Degradation of Hydrocarbons in Contaminated Vadose Zone
[Abstract]

An innovative foam-based method to deliver Fenton reagents (FR) and bacteria was assessed at field-scale to remediate a petroleum hydrocarbon (HC)-contaminated unsaturated zone. After surfactant foam injections, reagent solutions were delivered and propagated through a network of foam lamellae with a piston-like effect. Bench-scale experiments demonstrated the feasibility of the various treatments with HC removal efficiencies as high as 96%. Compared to the direct injection, the foam-based method led to larger radii of influence and a more isotropic delivery, and no detrimental effect regarding HC oxidation. Average degradation rates were increased by 20% despite 25% of HCs being expelled from the treated zone due to foam viscosity. Foam and reagent solutions injections in soil were tracked both using visual observation and differential electric resistivity tomography at field-scale. The latter demonstrated the controlled delivery of the reactive solutions using the foam-based method.

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.

Challenges of Soil Mixing Using Catalyzed Hydrogen Peroxide with Rotating Dual Axis Blending Technology
Kakarla, P., F. Symmes, M. Temple, V.D. Russo, E. Hall, W. Caldicott, and A. Hoffman.
Remediation Journal 27(3):45-54(2017) [Abstract]

At the Kearsarge Metallurgical Superfund Site in New Hampshire, an enhanced catalyzed hydrogen peroxide (CHP) modified Fenton's reagent (MFR) was applied using an innovative rotating dual-axis blender to mix the MFR into low-plasticity silt and clay soils to remediate residual 1,1,1-TCA, 1,1-DCE, and 1,4-dioxane. The remediation program was designed to treat ~3,000 cu yd of residual source area soil in situ by aggressively mixing in MFR from 7 to 15 ft bgs. The use of stabilizing agents along with careful calculation of the peroxide dose helped to ensure vapor-free conditions in the vicinity of the soil mixing operation. Post-treatment test results showed 1,1,1-TCA and 1,1-DCE concentrations at nondetect or below their cleanup goals of 150 µg/kg 1,1,1-TCA and 60 µg/kg 1,1-DCE, with these results verified at 6 and 12 months post-treatment. Additional information: Remedial Action Completion Report

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.

Federal Remediation Technologies Roundtable Cost and Performance Case Studies

• In Situ Chemical Oxidation, Soil Vapor Extraction, and In Situ Bio-Stimulation at Hanner's Dry Cleaners, Pompano Beach, Florida (2007)
• Soil Vapor Extraction and In Situ Chemical Oxidation at Swift Cleaners, Jacksonville, Florida (2007)
• Soil Vapor Extraction, Pump and Treat, and In Situ Chemical Oxidation at Dry Clean USA No. 11502, Orlando, Florida (2007)
• In Situ Chemical Oxidation Using Hydrogen Peroxide at Four Dry Cleaner Sites (2005)
• In Situ Treatment at Three Dry Cleaner Sites, Various Locations (2004)
  1) OZONE and 2) ISOTEC's
• In situ Chemical Oxidation Using Fenton's Reagent at Naval Air Station Pensacola, Florida (2001)
• In Situ Chemical Oxidation Geo-Cleanse Process at the Naval Air Station Pensacola Florida, Operable Unit 10, Pensacola, Florida (2000)
• In situ Chemical Oxidation Using Fenton's Reagent at Naval Submarine Base Kings Bay, Site 11, Camden County, Georgia (2000)

Field Evidence of Dissolution and Degradation Rates Enhancement During ISCR and ENA Treatments of Chlorinated Solvents
Barnier, C., C. Palmier, and O. Atteia.
Remediation Journal 23(1):123-137(2013)

Pilot tests were conducted to compare two methods of chlorinated solvent treatment at an automobile factory where two PCE sources had created two chlorinated solvent plumes. In situ reduction (EHC^®) was applied at the first source and enhanced natural attenuation (sodium propionate, sodium citrate, and sucrose) at the second. Despite an efficient treatment, the PCE and TCE concentrations remained virtually unchanged, whereas degradation rates increased. The authors estimate the dissolution enhancement during the two types of treatment and analyze the influence of each treatment on the increase of degradation kinetics. [This paper is Open Access via the "Get PDF" link.]

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. Additional information: DOE/EM-0484(1999)

Full Scale Pilot Test of a New UV/H₂O₂-Remediation Technique "RemUVe®" for Removal of Chlorinated Solvents and Pesticides to Reduced Usage of GAC on Remediation Facilities
Rahbek, R., M. Schouw, and M. Bymose.
AquaConSoil 2021, 15-17 June, virtual, abstract only, 2021

A full-scale pilot test using the new UV-technology RemUVe was conducted on the Grusgraven pump & treat (P&T) facility to reduce N,N-dimethylsulfamide (DMS) and chlorinated solvents in the water, decrease operating costs for existing and future P&T plants, and reduce activated carbon consumption. RemUVe is an advanced oxidation process created by combining UV light energy with very small amounts of hydrogen peroxide. The UV system has a unique reflection technique that lowers the energy consumption compared to traditional UV systems. The pumping rate of the system is ~20 m³/h. A part of the water stream, ~5 m³/h, went through the mobile RemUVe® system. Mapping with multiple settings of UV energy and H₂O₂ dosing were conducted to find the best combination dose to treat the water. The treatment goal was to reduce DMS to a level below the groundwater criteria at 0.1 µg/l. In the process, chlorinated solvents were reduced from 85-99%. The RemUVe system was set on continuous operation for 6 weeks with treatment monitoring. Results show that due to the reduction in chlorinated solvents and DMS, there is a potential to expand the lifetime of the GAC filters from 6 months to 4-5 years.

In-Situ Chemical Oxidation via Ozone at a Multiple-Remedy UST Site
F.R. Coll and R.A. Moore.
WM2009: Waste Management Conference, 1-5 March 2009, Phoenix, Arizona. Paper 9124, 12 pp, 2009

A multiple-remedy corrective action for BTEX and MTBE contamination at a former leaking underground storage tank site was complicated by its current occupation by an active retail establishment. ISCO via a patented combined ozone-hydrogen peroxide process was implemented in the former source area, replacing an SVE system. The remedial technology and design implemented resulted in significant reduction of source area concentrations and the associated development of subsurface conditions conducive to bioremediation. Additional remedial measures undertaken at the site include passive oxygen addition and plume cut-off.

Independent Review of the X-701B Groundwater Remedy, Portsmouth, Ohio: Technical Evaluation and Recommendations
B.B. Looney, C. Eddy-Dilek, J. Costanza, J. Rossabi, T. Early, K. Skubal, and C. Magnuson.
SRNL-STI-2008-00424, 83 pp, 2008

The review team (1) assessed the performance of an ongoing oxidant-based treatment technology that uses lances to inject catalyzed hydrogen peroxide, (2) provided specific recommendations for DOE and Ohio EPA to consider if oxidant injections are to be continued, and (3) recommended alternatives to the current remediation strategy for the X-701B TCE plume.

Independent Technical Review of the X-740 Groundwater Remedy, Portsmouth, Ohio: Technical Evaluation and Recommendations
B.B. Looney, D.G. Jackson, B.D. Riha, R. Ramirez, L. Whitehurst, and C.A. Eddy-Dilek.
SRNL-STI-2010-00176, 53 pp, 2010

Two technologies implemented at this site—phytoremediation using a stand of hybrid poplar trees from 1999-2007 and ISCO using modified Fenton's Reagent from 2008-2009—have proven ineffective in achieving remedial action objectives. The contaminated aquifer zone (the Gallia) is currently dominated by slow release of TCE from formations above, below, and within the Gallia itself. The review has indicated that the slow release of TCE from clay and sandstone into the Gallia represents a long-term source of TCE that can re-contaminate the Gallia in the future; hence, otherwise effective technologies that do not leave residual treatment capacity in the system are unlikely to achieve the cleanup goals. The review team classified 3 technologies as potentially viable: (1) enhanced anaerobic bioremediation using long-lived electron donor and low-pressure liquid deployment; PRBs; and passive upgradient drains to divert water around the contaminant source zone and plume.

Lessons Learned About the Nature of Groundwater Contamination by PAHs: A Case History-Based Discussion
Brassington, R.
Remediation Journal 23(1):103-121(2013)

This case study concerns the investigation and in situ chemical oxidation remediation of a water supply borehole contaminated by PAHs (fluoranthene, benzo-1,12-perylene, benzo-11,12-fluoranthene, benzo-3,4-fluorathene, and benzo-3,4-pyrene) originating from carbon black used in manufacturing. Two attempts were made to destroy the contaminants using hydrogen peroxide following different procedures. Results are reviewed to determine possible explanations for the observed behavior and to assess the effectiveness of the treatment methods. [This paper is Open Access via the "Get PDF" link.]

Multiphase Approach to Remediation Using Subsurface Fracturing, Surface Extraction and Modified Fenton Chemistry
Owens, D.C., Oxy Teknologies.
REMTECH 2010: The Remediation Technologies Symposium, Banff, AB, Canada, 20-22 Oct 2010. Environmental Services Association of Alberta, Edmonton, AB (Canada), 14 slides, 2010

ISCO with modified Fenton chemistry in conjunction with subsurface fracturing and surface extraction was conducted to remediate 11,325 cubic meters of diesel- and gasoline-contaminated soil and groundwater at a trucking terminal operated 24 hour per day without disrupting terminal operations. Free-phase liquid petroleum hydrocarbons (LPH) covered an area extending ~1,100 square meters. Subsurface fracturing was effective in about half the contaminated area and showed no significant results in the other half. Costs were high compared to the added value of the fracturing. The unpredictability of fracturing routes and fracture diffusion also are problems with this technology. Surface extraction of LPH was limited by cold surface conditions, limited fracturing effectiveness, and seasonality of the water table; overall, the method gave results equal or superior to pump and treat at significantly lower costs. ISCO with stabilized hydrogen peroxide was very effective in degrading the LPH in free, dissolved, and absorbed phases. The limiting factor was the ability to get the oxidant into contact with the LPH due to the tight soil conditions. Working conditions were difficult. Undermining the asphalt during ISCO was an ongoing problem but was handled with spot repairs. Winter conditions were also a limiting factor because of the difficulty of locating injection wells in snow and ice. The methods used in this remediation project resulted in cost savings of roughly $2.3 million when compared to standard dig and haul, plus an additional $3.6 million in potential relocation and lost business costs for a total savings of $5.9 million. In 10 months of treatment, the average thickness of LPH decreased 94%, while total dissolved-phase PHCs fell by 96%, demonstrating that a multi-phased remediation approach can provide remediation without disruption to an operating facility.

Periodic Review: Dexter Horton Building, Facility Site ID#: 68766933, 710 2nd Avenue, Seattle, Washington
State of Washington, Northwest Region Office, Toxics Cleanup Program, 27 pp, 2011

ISCO treatment with hydrogen peroxide was conducted under the Dexter Horton Building to remediate soil contaminated with Bunker C fuel oil in July and August 2005. Subsequent soil sampling showed that the ISCO treatment had reduced TRPH concentrations in soil from a pre-injection concentration of 18,000 mg/kg TRPH to a post-injection concentration of 400 mg/kg. A 'No Further Action' letter was issued February 16, 2006, with registration of a deed restriction owing to a small area of residual contamination that remains beneath the foundation.

State Coalition for Remediation of Dry Cleaners: Drycleaner Site Profiles

• City Hall (Former Swift Cleaners), Jacksonville Beach, Florida (2002)
• Daisy Fresh Dry Cleaners, College Park, Georgia (2002)
• Denver Colorado Dry Cleaner, Denver, Colorado (2001)
• Park Avenue Cleaners, Richardson, Texas (2000)
• Spin City Dry Cleaners, Plano, Texas (2000)

Ozone

BTEX Remediation under Challenging Site Conditions Using In-Situ Ozone Injection and Soil Vapor Extraction Technologies: A Case Study
Bhuyan, S.J. and M.R. Latin.
Soil and Sediment Contamination, Vol 21 No 4, 545-556, 2012

Remediation was completed successfully at a petroleum-contaminated site using ozone sparging combined with SVE for ~18 months, followed by one year of post-remediation monitoring at a site with high levels of BTEX contamination in dissolved, adsorbed, and free phases. The presence of fine-grained soil, shallow groundwater, and smear-zone contamination posed challenging cleanup conditions. During active and post-remediation periods, biodegradation also played a role in reducing the contaminant levels and bringing the site to closure. The cost of this remediation approach was estimated to be $72.08 per cubic meter. Longer abstract

Cleanup Update: Bay Shore Former Manufactured Gas Plant, Site 1-52-172, Bay Shore, NY
New York State Dept. of Environmental Conservation, Manufactured Gas Plant Program Fact Sheet, 9 pp, 2014

Substantial remediation progress has been made since major construction began in 2007 to support the cleanup activities in Bay Shore. National Grid has conducted or continued remedial activities at all four of the site's operable units. Although cleanup is not complete, contaminant levels for BTEX and PAHs are down sharply throughout the site, and this trend is expected to continue. All major construction is complete. The work entailed excavation of source areas to ~16-25 ft based on field conditions; removal and off-site thermal desorption of contaminated soil; in situ chemical oxidation using ozone to treat residual contamination beneath the excavated areas; installation of a subsurface barrier wall at the downgradient edge of OU-1 with in situ groundwater treatment immediately upgradient of the barrier; recovery of mobile water gas tar and DNAPL via extraction wells where practicable; and extensive use of oxygen injection (including injection of a chemical oxygen-releasing compound) to enhance bioremediation. See the Bay Shore Works website for project reports and other information, including progress videos. Additional Resources:

• The Chemical Oxidation of Polycyclic Aromatic Hydrocarbons at a Former Manufactured Gas Plant in Bay Shore, New York

Field Pilot Study of In Situ Chemical Oxidation Using Ozone and Hydrogen Peroxide to Treat Contaminated Groundwater at the Cooper Drum Company Superfund Site
U.S. EPA Region 9, 272 pp, 2006

A pilot-scale field evaluation was carried out to assess the effectiveness of ISCO using ozone, with and without hydrogen peroxide, to remediate 1,4-dioxane and chlorinated VOC in groundwater at the Cooper Drum Company site in Los Angeles County, CA. The pilot study took place between July 2005 and June 2006 for a period of 321 days, and results showed that ozone alone, as well as ozone combined with hydrogen peroxide, was effective in destroying up to 90% of all contaminants of concern.

Hampton Hotel (T0607900034), Cambria, California
California State Water Resources Control Board, GeoTracker Database, Nov 2012

The underground tanks, fuel piping, and dispenser of a former retail gasoline service station were removed in January 1994, and the Central Coast Water Board became the lead agency for investigation and cleanup of the hotel property. Remedial efforts included periodic 15-day dual-phase extraction events between May 2001 and January 2003, and again between June 2004 and April 2006. These activities removed soil vapors, ~25,615 gallons of fuel-contaminated groundwater, and about 8,548 pounds of hydrocarbons. A total of 1,873 lbs of ozone was injected across the groundwater plume through 18 ozone sparging well points between January 2008 and February 2011 with no significant rebound in concentrations after system shutdown.

Innovative Technology Pilot Program Remediation Summary Report: Strickland Contracting Company, Quincy, Gadsden County, Florida
Florida Department of Environmental Protection, Bureau of Petroleum Storage Systems, Tallahassee, FL. 17 pp, 2007

In March 2005, operation of the pilot system began using low flow-rate ozone and oxygen injection to initiate chemical oxidation of petroleum compounds (2 distinct areas of diesel and gasoline) and enhance their biodegradation by elevating DO concentrations in the groundwater. Soil and groundwater remediation success was achieved during a 10-month period of operation in subsurface conditions of tight soil with low groundwater transmissivity.

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.

Successful Ozone Applications with Petroleum Hydrocarbons
Piper, J. and J. Salvage.
IPEC 2012: Proceedings of the 19th International Petroleum & BioFuels Environmental Conference, October 29 - November 1, 2012, San Antonio, Texas. 44 slides, 2012

Four case studies (one ex situ and three in situ) illustrate successful implementation of ozone injection to reduce No. 6 fuel oil, LNAPL, PAH, BTEX, VOCs, and TPH. Some case studies indicate ozone influence over more than triple the commonly accepted radius of influence. Designs include utilizing ozone as a curtain or barrier to eliminate off-site migration, hot spot treatment, and site polishing.

Permanganates

A Full-Scale Demonstration of In Situ Chemical Oxidation through Recirculation at the X-701B Site
West, O.R., 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. Additional information: Innovative Technology Summary Report, DOE/EM-0496

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

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

Delineation to Delivery: Optimization of ISCO with Hydraulic Fracturing at the Hemphill Road TCE Superfund Site
Fulkerson, M., C, Allen M. Perlmutter, T. Williams, D. Seadler, and B. Bentowski. DCHWS East 2024 Spring Symposium, 10-12 April, Philadelphia, PA, 13 slides, 2024

Recycling of chemical drums by emptying their residual contents on the ground surface, and then burning and crushing the drums resulted in TCE-contaminated groundwater at the Hemphill Road Superfund site. To accelerate and optimize the restoration process, EPA prepared an Interim Action Record of Decision that included a phased remedial action to address the areas with TCE concentrations >300 µg/L first and the residual groundwater plume (TCE concentrations >5 µg/L) later. Following pilot tests, ISCO was selected as the remedial approach, with potassium permanganate injected into the partially weathered rock (PWR) and saprolite overburden using hydraulic fracturing technology. The target treatment zone extended from the groundwater table (~30 ft bgs) to the top of the bedrock (~60 ft bgs). A baseline groundwater sampling event and a dynamic plume delineation investigation were conducted to confirm the area requiring treatment and finalize the ISCO design. Permanganate injections were conducted using proprietary hydraulic fracturing technology to distribute 182,000 lbs of RemOx-S at 26 locations throughout the plume on 30-ft centers. Fractures were created approximately every five vertical ft from the water table, at ~ 30 ft bgs, to bedrock. Performance monitoring will be conducted at 1, 3, and 6 month intervals post-injection to evaluate the effectiveness of the remedy and inform the need for additional injections.

Demonstration of ISCO Treatment of a DNAPL Source Zone at Launch Complex 34 in Cape Canaveral Air Station
2002. A. Gavaskar and W. Yoon, Battelle Memorial Inst., Columbus, OH. AFRL-ML-TY-TR-2003-4522, NTIS: ADA414447, 295 pp.

Details for Site ID 3222, Springvilla Dry Cleaner
Oregon Department of Environmental Quality (DEQ), Environmental Cleanup Site Information Database.

DEQ, with cooperation from the owner, McKay Investment Company, conducted a removal action in August and September 2004 to address the PCE in source soils present beneath the former dry cleaner building. McKay removed the cleaner's building and temporarily supported the adjacent building to allow DEQ's contractor to excavate about 150 cubic yards of soil from the former dry cleaning operation and treat it on site by SVE with vapor-phase carbon filtration to below residential risk-based levels. During excavation, the contractor installed subsurface piping near the water table to allow for injection of chemical or biological agents. In September 2004, 1,100 gallons of 4% sodium permanganate solution were injected into the gallery to address residual hot-spot soil and groundwater contamination. A groundwater bioremediation project was implemented in August 2007 to reduce levels of VOCs at and downgradient of the former dry cleaner. In August 2009, DEQ injected emulsified oil into direct push borings in a grid array beneath the adjacent building as part of the removal action to reduce VOC concentrations in underlying shallow groundwater and to mitigate potential vapor intrusion issues. Groundwater recirculation ended in late August 2009.
Additional information:

• State Coalition for Remediation of Drycleaners Site Profile (2006)
• Former Springvilla Dry Cleaners 2006 Interim Removal Action Measure Report (ISCO)
• Large Scale Bioremediation Using Multiple Electron Donors (2009)
• Optimizing Remediation Strategies for a Former Dry-Cleaner Site (2010, abstract only)
• Former Springvilla Dry Cleaners 2009 Interim Remedial Action Measure Data Summary Report (Biostimulation)

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.

Federal Remediation Technologies Roundtable Cost and Performance Case Studies

• Remediation of DNAPL through Sequential In Situ Chemical Oxidation and Bioaugmentation (2010)
• Using Electrical Resistivity Imaging to Evaluate Permanganate Performance During In Situ Chemical Oxidation Treatment of a RDX-Contaminated Aquifer (2010)
• In Situ Chemical Oxidation at Four Dry Cleaner Sites, Various Locations (2005)
• In Situ Chemical Oxidation (ISCO) Treatment of DNAPL Source Zone at Launch Complex 34, Cape Canaveral Air Force Station, Florida (2003)
• Pump and Treat, In Situ Chemical Oxidation, and Soil Vapor Extraction at the Union Chemical Company Superfund Site, South Hope, ME (2001)
• In Situ Chemical Oxidation Using Potassium Permanganate at Portsmouth Gaseous Diffusion Plant, X-701B Facility (2000)

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.

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. More information about this cleanup]

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.

Remediation System Evaluation: 10th Street Superfund Site, OU2, Columbus, Nebraska
U.S. EPA, Office of Superfund Remediation and Technology Innovation (OSRTI).
EPA 540-R-10-012, 77 pp, Feb 2010

Groundwater contamination at the 10th Street Superfund Site consists primarily of PCE, TCE, and cis-1,2-DCE. Three active components provide the groundwater remedy: 1) a groundwater extraction and treatment (GET) system; 2) an AS/SVE system located at the One Hour Martinizing (OHM) source area; and 3) ISCO treatment at the OHM source area and also at locations between OHM and the GET system. Optimization recommendations are provided in four primary categories: effectiveness, cost reduction, technical improvement, and sustainability.

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

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.

Sites 2 and 12 In-Situ Oxidation Pilot Study Report, Former Fort Ord, California
2003. Harding Engineering & Environmental Services, Novato, CA. 45 pp.

A pilot study was conducted to evaluate site-specific conditions associated with in situ chemical oxidation using potassium permanganate for vinyl chloride in ground water and to establish preliminary design and performance criteria for full-scale implementation.

Stabilizing the NAPL Threat: In-Situ Biogeochemical Stabilization and Flux Reduction Using Catalyzed Permanganate
J. Mueller, J. Moreno, M. Dingens, and P. Vella.
Pollution Engineering, Mar 2007

Creosote and pentachlorophenol were found over an 11,000 cubic meter volume in consolidated shallow alluvium deposit at an operating wood treatment facility in Colorado. In pilot-scale field studies of in situ biogeochemical stabilization initiated in 2002, 24,050 gallons of a 3% aqueous potassium permanganate solution were injected into 13 locations within a test area, achieving rapid and complete stabilization of NAPL, contaminant mass reduction of 10 to 79%, and flux reduction of 56 to 99%. Regulators approved a full-scale application of the technology at the site.

State Coalition for Remediation of Dry Cleaners: Drycleaner Site Profiles

• American Cleaners, St. Peters, Missouri (2005)
• Barb & Ron's Cleaners, Appleton, Wisconsin (2004)
• Former Cowboy Cleaners, Broomfield, Colorado (2001)
• One Hour Martinizing, Darlington, South Carolina (2003)
• Paramount Cleaners, Florissant, Missouri (2003-2004)
• Quick-N-Easy Wash-O-Mat and Artistic Cleaners, Wichita, Kansas (1999)
• Rummel Creek Shopping Center, Houston, Texas (2001)

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

Successful Unsaturated Zone Treatment of PCE with Sodium Permanganate
J.R. Hesemann and M. Hildebrandt.
Remediation Journal, Vol 19 No 2, p 37-48, 2009

A pilot test of ISCO with permanganate to reduce PCE soil concentrations within the source area was conducted at an active dry cleaner located in Topeka, Kansas, where a relatively small area of residual contamination adjacent to the active facility building was identified as the source of a large, site-wide groundwater contamination plume with off-site receptors. The pilot-test approach consisted of injecting aqueous sodium permanganate using direct-push technology with a sealed borehole, and ~12,500 pounds of sodium permanganate was injected at a concentration of ~3% (by weight). Confirmation soil sampling conducted after the injection event indicated PCE reductions ranging from 79 to >99%. After additional injection of 6,200 pounds of sodium permanganate to address residual soil impacts in the soil source zone, confirmation sampling indicated a PCE reduction of >90% at the most heavily contaminated sample location and additional reductions in four of the six samples collected.

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 the chemical oxygen demand of the sediments themselves is an important factor in planning a remedial action.

Using Electrical Resistivity Imaging to Evaluate Permanganate Performance during an In Situ Treatment of a RDX-Contaminated Aquifer
S. Comfort, V. Zlotnik, and T. Halihan.
Environmental Security Technology Certification Program (ESTCP), Project ER-0635, 132 pp, 2009

Electrical resistivity imaging (ERI) is a geophysical technique that can infer subsurface water and soil electrical properties, providing a spatially extensive, high-density, high-quality model of subsurface conditions. ERI was used to monitor an injection of sodium permanganate to mineralize RDX at the former Nebraska Ordnance Plant. [RDX and TCE were commingled in the plume, but TCE is not discussed.] ERI showed that the permanganate injection flowed against the regional groundwater gradient, and that the solution was able to sink below the monitoring well screens. Without geophysical observations, no information would have been available to explain the permanganate and RDX concentrations observed in the wells. The same data were used to guide the boring of additional holes. See also the ESTCP Cost and Performance Report.

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, Cincinnati, OH.
EPA 540-R-07-005, 96 pp, 2007

Describes an evaluation of the XDD ISCO process using potassium permanganate at a site in Hudson, NH, to address chlorinated volatile organics, including PCE, TCE, cDCE, 1,1,1-TCA, and 1,1-DCA.

Persulfate

Case Study Comparison of Multiple Activation Methods for Sodium Persulfate ISCO Treatment
G. Cronk.
Sixth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 19-22, 2008, Monterey, California. Battelle Press, Columbus, OH. 8 pp, 2008.

Six brief in situ chemical oxidation (ISCO) case studies (full and pilot scale) from sites in California illustrate the use of different methods--hydrogen peroxide, ferrous or chelated iron, alkaline conditions (high pH)--for persulfate activation. Good to excellent contaminant reductions (generally >85%) were achieved in all 6 cases for contaminants such as 1,4-dioxane and chlorinated solvents (2), a mixed chlorinated solvent plume (1), methylene chloride DNAPL (1), gasoline-range hydrocarbons (1), and benzene (1).

Coal Tar Contamination Remediation
Collins, J.
Pollution Engineering 44(5):26-30(2012) [a Pollution Engineering white paper]

At a New York City brownfield, site of a former roofing products manufacturer, a surfactant-enhanced ISCO (S-ISCO) system was implemented to remediate coal tar present as residual NAPL held within the pore spaces of the predominately sandy and silty soil, which included lenses of silt and silty clay. A patented, plant-based surfactant/co-solvent mixture and alkaline-activated sodium persulfate were delivered into the subsurface using a pressure-pulsing injection enhancement technology. Between October 2010 and March 2011, the supplier conducted five months of S-ISCO injections that destroyed >90% of coal tar-related contaminants—PAHs, naphthalene, and BTEX—in the targeted interval. Additional information: See another paper on this cleanup by Dahal et al. in Remediation Journal 26(2):101-108(2016)

Combined Remedy Treatment of Multi-Chemical Solvent Plume in Low Permeability Clay
Brab, B. ǀ 10th Annual AIPG Michigan Section Technical Workshop, 15-17 June, virtual, abstract only, 2021

A phased approach utilizing combined remedies was selected to remove contaminants, including halogenated solvents, methylisobutyl carbinol (MIBC), and NAPL in soil and groundwater at a former chemical plant. Remedies included 1) an off-site in-situ permeable reactive barrier utilizing Trap & Treat® BOS 100® to capture dissolved impacts and 2) shallow soil mixing using activated persulfate to mitigate unsaturated soil impacts. Trap & Treat® BOS 100® + ERD was utilized to mitigate saturated source mass soil and groundwater impacts and off-site sources during Phases 1 and 2. CAT 100 injections were also conducted in the source area. The presentation discusses the development of the CSM and the remedial action, including characterizing and injecting products into tighter units. Investigative efforts evolved to accommodate expansive clays during drilling and manage exposure to NAPL concentrations in the site source area soil. The use of a new and cutting-edge application of cometabolic synergy: granular activated carbon impregnated with metallic reactive iron coupled with an enhanced reductive chlorinating biological component is also discussed. Improved in-situ injection techniques were developed to increase effectiveness and installation throughout all planned phases. Site geology dictated multiple point installation to permit dissipation of injection pressure following completion of each injection interval.

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.

Cost And Performance Report for a Persulfate Treatability Study at Naval Air Station North Island
Gavaskar, A. and W. Condit, Battelle Memorial Institute, Columbus, OH.
NAVFAC Engineering Service Center, Port Hueneme, CA. TR-2306-ENV, 28 pp, 2008

A pilot treatability study of persulfate was conducted at Operable Unit 20, Naval Air Station North Island, between November 2006 and June 2007. The groundwater treatment targeted the removal of chlorinated VOCs (primarily TCE) located at a depth of up to 54 ft bgs.

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.

Evaluation of Lime and Persulfate Treatment for Mixed Contaminant Soil from Plum Brook Ordnance Works (Sandusky, OH)
V.F. Medina, S.A. Waisner, A.B. Morrow, C.C. Nestler, and M. Jones.
ERDC/EL TR-07-19, 116 pp, 2007

Soil contaminated with TNT, DNT, a PCB (Aroclor 1260), PAHs, and lead was addressed with a series of chemical-based treatments, i.e., application of lime to treat the explosives, advanced oxidation (persulfate and Fenton's reagent) for treatment of PCBs and PAHs, and use of phosphate for stabilizing lead. Lime treatment degraded 98% of TNT, 75% of DNT, and 80% of PCBs, with minimal removal (41%) of PAHs. Similar removal levels were found for persulfate treatment and lime followed by persulfate. Treatments of the most contaminated soil did not meet preliminary remediation goals for explosives or PCBs.

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.

Focused In-Situ Chemical Oxidation of Chlorinated VOCs and 1,4-Dioxane Using Sodium Persulfate in Fine-Grained Soils
K.S. Houston, J. Horst, and G. Wroblewski.
Pollution Engineering, 8 pp, Mar 2009

At a former machining and metal working site where the groundwater is affected by PCE, TCE, 1,1-DCE, and 1,4-dioxane, focused ISCO using sodium persulfate was considered for discrete source mass treatment to expedite mass removal and decrease the operational timeframe, but lab treatability tests indicated that strategic oxidant dosing would achieve the remediation goal. In a field pilot test, effective 1,4-dioxane and VOC treatment was achieved, likely the result of naturally occurring reduced metals (e.g., ferrous iron) that facilitated sulfate radical formation, which also showed that oxidant field loading based solely on lab-determined total oxidant demand of site soil and groundwater slurries can overstate the mass of oxidant required to achieve effective treatment.

In Situ Stabilization and Solidification (ISS) + ISCO: Benefits of Adding Sodium Persulfate to S/S Binders
East Land Quality Forum Webinar, 30 minutes, 23 July, 2020

This presentation reviews the advantages and limitations of combining ISCO and ISS to treat contaminated soil from petroleum hydrocarbon sites. Current literature is reviewed as well as bench and field data demonstrating the successes of ISCO-ISS as a combined remedy. Activated sodium persulfate was found to have chemically oxidized a significant portion of the contaminants of concern (COC) for all the ISCO/ISS treatments, and the mass of COCs oxidized increased with increasing dose. The lowest molecular weight contaminants were preferentially oxidized. For the same Portland cement dose, combined ISCO/ISS treatment was more effective in reducing contaminant leachability than ISS treatment alone because of the COC removal achieved by the ISCO (activated sodium persulfate) component. More Information: Slides ; Sollerod Gasaerk MGP project ; Bolzano, Italy site

In-Situ Chemical Oxidation to Address Residual VOC Plumes on the Savannah River Site
Seaman, J.C., B. Kramer, J. Kupar, M. Malin, and P.C. Knapp.
Proceedings of the 2011 Georgia Water Resources Conference, April 11-13, 2011, University of Georgia. Abstract only, 2011

A field-scale demonstration was conducted to evaluate ISCO for residual TCE on DOE's Savannah River site. TCE concentrations in the plume ranged from 10 to 40 mg/L. Catalyzed persulfate was injected intermittently over a 10-day period as 10 oxidant batches (~230 g sodium persulfate/L) totaling 4,800 gallons (18,168 L). Quantifiable concentrations of persulfate were detected in observation well 1 (OW1) ~2 weeks after injection, peaking at ~150 mg/L and then slowly decreasing over 295 days of monitoring. Subsequent lab experiments confirmed the somewhat limited mobility of persulfate in the SRS subsurface environment due to sorption in Fe-oxide rich materials. Batch results confirmed the continued effectiveness of persulfate in degrading VOCs in the absence of an activating agent at the relatively low persulfate concentrations (< or = 192 mg/L) observed in OW1. Additional information: 21 slides about this project Laboratory and Modeling Efforts

In-Situ Remediation Pilot Study Report Area of Concern I (AOC I): Atlantic Fleet Weapons Training Area, Vieques Former Naval Ammunition Support Detachment, Vieques, Puerto Rico
Naval Facilities Engineering Command Atlantic, 930 pp, 2013

This report summarizes the activities performed and data obtained during the ISCO and EISB pilot study conducted at AOC I, a former asphalt plant that operated from the 1960s through 1988. The pilot addressed benzene, bis(2-ethylhexyl)phthalate, 1,2-dichloroethane, 1,2-dichloropropane, 2-methylnapthalene, and naphthalene contamination in the groundwater. The pilot was implemented in a two-step systematic approach—ISCO using injection of sodium persulfate (sodium hydroxide alkaline-activated Klozur) directly followed by EISB (oxygen-releasing compound "socks")—to oxidize organics and then increase the intrinsic biodegradation rate to reduce the attenuation time needed to achieve acceptable contaminant concentrations in groundwater. The baseline monitoring and ISCO injection were initiated in March 2010, followed by a post-injection monitoring event, application of EISB, and then three additional post-injection performance monitoring events, with the last monitoring event completed in November 2012.

Non-Invasive Survey Technology for Estimating the Distribution of Oxidant Solution: A Pilot Injection Study
Tsai, Y.-J., T.-N. Wu, C.-H. Lee, S.-L. Lin, and W.-H. Tsai.
Journal of Contaminant Hydrology 239:103779(2021) [Abstract]

Magnetometric resistivity was applied to survey the distribution of an injected oxidant during an in situ chemical oxidation (ISCO) application. Sodium persulfate was applied via four pulse injections from one injection well at a 10 m x 10 m test site. A magnetic field survey coupled with conventional monitoring was performed before the initial injection and after each pulse injection. While groundwater samples from six observation wells and seven direct-push electrical conductivity, loggings did not provide sufficient data to quantify the distribution and flow behavior of the injected oxidant, the magnetic field survey visually showed the dynamic distribution of the injected oxidant. Flow pathways and flow behavior were assessed accordingly. Overall, the magnetic field survey combined with the monitoring of the well samples helped explain abnormal changes in the electrical conductivity of the observation wells and supported the use of the magnetic field survey technology to monitor ISCO injections.

Optimizing Injection-Based Remediation in Bedrock: Lessons from DNAPL Remediation by Chemical Oxidation
Dombrowski, P. | DCHWS 2021 Design and Construction at Hazardous Waste Sites Virtual Symposium, 29-30 March and 1 April, Virtual, 19 slides, 2021

Presentation describes an application of ISCO to treat bedrock groundwater contamination. It looks at the lessons learned over four injections of sodium persulfate to treat bedrock contaminated with PCE DNAPL.

Revisiting a Closed Site: Expedited Treatability Testing and High Pressure Injection of Activated Sodium Persulfate to Move Site toward Closure, Again
Jacobs, J.A., A. Adini, and D. Rao.
The 20th International Conference on Soils, Sediments, Water and Energy, March 15-18, 2010, San Diego, California. Poster presentation, 2010

A 3,000-gallon gasoline underground storage tank in the Charnock Sub-Basin in Los Angeles was removed and remediation was considered complete in 1997, but the case was reopened in 2000 following MTBE discoveries in the area. In 2007, treatability testing was performed for ISCO using Fenton's reagent and sodium persulfate with three activators. A one-week ISCO pilot test in April 2008 used 10 closely spaced probe-driven injection ports to inject 10,000 gallons of treatment chemicals using computer-controlled, high-pressure injection equipment. The pilot achieved average soil concentration reductions of TPH-g, BTEX, and MTBE >60%. Average shallow groundwater concentrations in nearby groundwater wells showed reductions of over 99% for TPH-g and benzene. Full-scale treatment took place in April 2009, when 12,000 gallons of sodium persulfate and iron EDTA Catalyst with no pH adjustment were injected into a closely spaced injection matrix of 12 ports in the treatment zone.

Sodium Persulfate with Integrated Activator Destroys >99% Of Trichlorethylene in 5 Weeks at a Manufacturing Facility in the Netherlands
Mueller, M., H. Opdam, and J. van Doren.
AquaConSoil 2021, 15-17 June, virtual, abstract only, 2021

Klozur® CR was successfully applied at a former petrol station in northern Italy characterized by groundwater contamination, including hydrocarbons (C<12 ~2,000 µg/L), benzene (~500 µg/L), ethylbenzene (~ 380 µg/L) and MtBE (~ 13,000 µg/L). A total of 4,800 kg of Klozur CR (in a 25% aqueous solution) were injected in two events conducted 15 months apart. Following 18 months after the first application, contaminant concentrations were below the remediation goals in monitoring piezometers in the treatment area. TPH was reduced by >80%, while MtBE was reduced by >90 %. Monitoring data confirmed sustained elevation of oxidation-reduction potential and dissolved oxygen as necessary subsurface conditions to support treatment.

Source Area MIP Investigation and Pilot-Scale Groundwater Remediation Using Activated Persulfate
Rees, A. and T. Taylor.
AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California. Poster, Search and Discovery #80246, 2012

An ISCO pilot test was performed at a site in Southern California in 2010 to address residual gasoline free product and high concentrations of BTEX and MTBE. High-resolution results from a membrane interface probe investigation to characterize the lithology and total VOCs in the source area were used to design the ISCO injection grid. A mixture consisting of 6,600 lbs of sodium persulfate mixed with 660 pounds of iron EDTA and water was injected across the top 10 ft of the saturated zone using direct-push methods. Persulfate distribution and oxidation were achieved within the injection zone, 20 ft cross-gradient, and 35 ft downgradient. Although the iron-activated persulfate effectively reduced dissolved-phase VOC concentrations, rebound was observed.

Sustained In situ Chemical Oxidation (ISCO) of 1,4-Dioxane and Chlorinated VOCs Using Slow-Release Chemical Oxidant Cylinders
Evans, P., J. Hooper, M. Lamar, D. Nguyen, P. Dugan, M. Crimi, and N. Ruiz.
ESTCP Project ER-201324, 576 pp, 2018

Slow-release chemical oxidant cylinders were applied to the treatment of a plume containing 1,4-dioxane and chlorinated VOCs (1,2-DCE, 1,1-DCA, cis-1,2-DCE, and TCE) in a technology demonstration conducted at Naval Air Station North Island, Calif. The objectives were to demonstrate and evaluate the technology's effectiveness, sustainability, longevity, oxidant transport and destruction, implementability, secondary water quality impacts, and technology reproducibility. Unactivated persulfate embedded in a slow-release paraffin wax formulation was emplaced in two 4-inch wells housed inside 18-inch diameter boreholes. The majority of the project's performance objectives were met. The oxidant cylinders are commercially available, but equipment for suspending cylinders in wells or reactive gates is not standardized and will require engineering design and possible custom fabrication. Additional information: ESTCP Cost and Performance Report .