******************************************************* CHEMICAL DECOMPOSITION This profile provides the following general information about chemical decomposition: 1. Description 2. Applicability 3. Limitations 4. Availability and vendor list 5. Performance data and field applications 6. Sources of information for this profile 1. DESCRIPTION Two types of chemical decomposition are generally available for PCB treatment in soil: an alkaline polyethylene glycole (APEG) process and base catalyzed decomposition (BCD). Both treatment processes decompose the PCB molecule and other chlorinated organics. They can be used as stand-alone technologies, or in combination with other technologies. For example, they can be preceded by a separation technology to reduce the volume of waste that requires decomposition. Another technology, catalytic dechlorination (trade name XeChlor), is under development at Princeton University. APEG is a full-scale technology in which an alkaline polyethylene glycol reagent is used to dehalogenate halogenated aromatic compounds in a batch reactor. Potassium polyethylene glycol (KPEG) is the most common APEG reagent. Contaminated soils and the reagent are mixed and heated in a treatment vessel. In the APEG process, the reaction causes the polyethylene glycol to replace halogen molecules and render the compound nonhazardous or less toxic. For example, the reaction between chlorinated organics such as PCBs and KPEG causes replacement of a chlorine molecule and results in a reduction in toxicity. Treatment of the wastewater generated by the process may include chemical oxidation, biodegradation, carbon adsorption, or precipitation. The metal hydroxide that has been most widely used for this reagent preparation is potassium hydroxide (KOH) in conjunction with polyethylene glycol (PEG) (typically, average molecular weight of 400) to form a polymeric alkoxide referred to as KPEG. Sodium hydroxide has also been used in the past, however, and most likely will find increasing use in the future because of patent applications that have been filed for modification to this technology. This new approach will expand the technology"s applicability and efficacy and should reduce chemical costs by facilitating the use of less costly sodium hydroxide. A variation of this reagent is the use of potassium hydroxide or sodium hydroxide/tetraethylene glycol, referred to as ATEG, that is more effective on halogenated aliphatic compounds. In some KPEG reagent formulations, dimethyl sulfoxide (DMSO) is added to enhance reaction rate kinetics, presumably by improving rates of extraction of the haloaromatic contaminants. Previously developed dehalogenation reagents involved dispersion of metallic sodium in oil or the use of highly reactive organosodium compounds. The reactivity of metallic sodium and these other reagents with water presented a serious limitation to treating many waste matrices; therefore, these other reagents are not discussed here and are not considered APEG processes. The reagent (APEG) dehalogenates the pollutant to form a glycol ether and/or a hydroxylated compound and an alkali metal salt, which are water-soluble byproducts. The base-catalyzed decomposition (BCD) process was developed by EPA's Risk Reduction Engineering Laboratory (RREL), in cooperation with the National Facilities Engineering Services Center (NFESC) to remediate soils and sediments contaminated with chlorinated organic compounds, especially PCBs, dioxins, and furans. Contaminated soil is screened, processed with a crusher and pug mill, and mixed with sodium bicarbonate. The mixture is heated to above 330 澧 (630 澹) in a rotary reactor to decompose and partially volatilize the contaminants. These moderately elevated temperatures are similar to those used in thermal desorption, and are lower than temperatures required for incineration. The contaminant is partially decomposed rather than being transferred to another medium. Whereas alkaline polyethylene glycol (APEG) residuals contain chlorine and hydroxyl groups, which make them water-soluble and slightly toxic, the BCD process produces primarily biphenyl and low-boiling point olefins, which are not water-soluble and are much less toxic, and sodium chloride. 2. APPLICABILITY The target contaminant groups for glycolate dehalogenation are halogenated SVOCs and pesticides. The technology can be used but may be less effective against selected halogenated VOCs. APEG dehalogenation is one of the few processes available other than incineration that has been successfully field tested in treating PCBs. The technology is amenable to small-scale applications. The target contaminant groups for dehalogenation (BCD) are halogenated SVOCs and pesticides. The technology can be also used to treat halogenated VOCs but will generally be more expensive than other alternative technologies. 3. LIMITATIONS Factors that may limit the applicability and effectiveness of the APEG process include: - The technology is generally not cost-effective for large waste volumes. - Media water content above 20% requires excessive reagent volume. - Concentrations of chlorinated organics greater than 5% require large volumes of reagent - Factors that may limit the applicability and effectiveness of the BCD process include: - High clay and moisture content will increase treatment costs. 4. AVAILABILITY AND VENDOR LIST Chemical decomposition has been demonstrated at full-scale to effectively treat PCBs, and is commercially available. SDTX Technologies (APEG) 609-452-0955 USEPA RREL (BCD) 513-569-7626 Separation & Recovery (BCD) 714-261-8860 ETG (BCD) 610-832-0700 SoilTech (BCD) 219-929-4343 RUST (DeChlor KGME) 708-947-3762 Princeton University 609-258-3926 (Catalytic Dechlorination, XeChlor) Xetex (XeChlor) 212-599-3131 A.L. Sandpiper Corp. 614-486-0405 5. PERFORMANCE DATA AND FIELD APPLICATIONS Chemical decomposition has been selected or applied at the following sites: ________________________________________________________ Site Meyers Property Superfund Site, NJ ROD 2/28/90 Status Remedy Dechlorination followed by soil washing. Media 49,000 cy soil and 1000 cy sediment Contaminants SVOCs( hexachlorobenzene), Pesticides (DDT, DDE, DDD) and Dioxins (2378-TCDD) Source Pesticide manufacturer Lead Agency PRP lead, federal oversight. M&E Contact John Prince 212-264-1213. _________________________________________________________ Site Wide Beach Development Superfund Site, NY ROD 9/30/85 Status Remediation complete; operational 10/90 to 6/91 Remedy APEG dechlorination combined with Thermal Desorption (SoilTech) Media 40,000 c.y. soil Contaminants PCBs Source Roads, driveways and ditches sprayed with contaminated oil for dust control Lead Agency Federal lead Contact Herb King 212-264-1129 _________________________________________________________ Site Saunders Supply Co., OU 1, VA ROD 9/30/91 Status Treatability studies in progress 3/95. Operation planned for spring 96. Remedy Dechlorination for sludge, thermal desorption for soil. Media Sludge and soil Contaminants dioxin, PCP, arsenic Source wood preserving Lead Agency Federal lead Contact Andy Palestini 215-597-1286 _________________________________________________________ Site Smiths Farm Brooks, OU 1, KY ROD 9/30/91 Status Remediation completed Spring 95 Remedy BCD: Dechlorination combined with thermal desorption (soil phase only) Media 16,000 c.y. soil Contaminants PCBs Source drum storage, disposal Lead Agency PRP lead Contact Tony D'Angelo 404-347-7791 _________________________________________________________ Site Signo Trading, Mt. Vernon, NY ROD Action Memo date 12/19/86 Status Completed; operational during October 1987 Remedy Dechlorination (Galson Research Corp, sub to OHM) Media 15 gallons sludge Contaminants Dioxins (2378 TCDD-laden herbicides) Concentration 135 ppb before treatment, less than 1 ppb after treatment Source Waste Management Facility Warehouse Lead agency Federal lead Contact Charles Fitzsimmons 201-321-6608 _________________________________________________________ Site Fruitland Drum, NM ROD Action Memo date 9/8/90 Status Remedy Dechlorination Media 150 gallons liquid Contaminants VOCs, pesticides, dioxins (235-T), PAHs Source Operation, maintenance facility Lead agency Federal lead (EPA Region 6) Contact Craig Carlton 214-665-6444 (main) _________________________________________________________ Site Crown Plating ROD Action memo date 8/29/89 Status completed; operational from Oct-Dec 1989 Remedy Dechlorination Media 55 gallons liquid Contaminants Pesticides (silvex, 245 TP) Source Electroplating Lead agency Federal lead Contact Mark Roberts 913-236-3881 _________________________________________________________ Site US Public Works Center, Guam (Taylor et al, 1989) Status Operational Remedy Dechlorination (BCD- Battelle) Media 5500 cy soil Contaminants PCBs Source Federal Facility Lead Agency Contact _________________________________________________________ Site Koppers Company Superfund Site, Morrisville, NC Status SITE Demonstration complete Remedy BCD (ETG, SRS SAREX Therm-O-Detox) for soil Media Soil, groundwater Contaminants PCP, dioxin, furan Contact Diane Barrett 1-800-435-9233 or 404-347-7791 _________________________________________________________ Site Re-Solve Superfund Site, MA ROD 9/24/87 Status Complete: Remedy Soil was treated with thermal desorption, then a demonstration of chemical dechlorination was performed on the concentrated liquid by-product. (RUST Remedial Services, RUST Federal Services, XTRAX and DeChlor/KGME) Media 22,500 cy soil Contaminants PCBs Source chemical reclamation facility Lead agency PRP lead Contact John Lemay 617-573-9622 _________________________________________________________ Site Sol-Lynn, Texas ROD March 1988 _________________________________________________________ Site Montana Pole, Butte, MT (des Rosiers, 1986) ROD 1986 Remedy Glycolate dechlorination of oil Media 10,000 gallons oil Contaminants dioxins, furans Concentration up to 83,923 ppb before treatment, less than 1 ppb after treatment _________________________________________________________ Site Western Processing, Kent WA (Tieman, 1989) ROD 1986? Remedy Glycolate dechlorination of liquid and sludge Media 7500 gallons liquid and sludge Contaminants dioxin Concentration 120 ppb reduced to less than 0.3 ppb _________________________________________________________ Site Benart & Memel, Buffalo, NY (Novosad, 1987) Remedy Dechlorination Media 52 drums of soil (55-gal each) Contaminants PCBs Concentration 1008 ppm reduced to less than 27 ppm _________________________________________________________ Site Economy Products, Omaha, NE ROD 1987? Remedy Dechlorination Media 20 gallons liquid Contaminants TCDD, 24-D, 245-T Concentration TCDD: 1.3 ppm reduced to ND 2,4-D: 17,800 ppm reduced to 334 ppm 2,4,5-T 2,800 ppm reduced to 55 ppm _________________________________________________________ This technology uses standard equipment. The reaction vessel must be equipped to mix and heat the soil and reagents. A detailed engineering design for a continuous feed, full-scale PCB treatment system for use in Guam is currently being completed. It is estimated that a full-scale system can be fabricated and placed in operation in 6 to 12 months. The concentrations of PCBs that have been treated are reported to be as high as 45,000 ppm. Concentrations were reduced to less than 2 ppm per individual PCB congener. PCDDs and PCDFs have been treated to nondetectable levels at part per trillion sensitivity. The process has successfully destroyed PCDDs and PCDFs contained in contaminated pentachlorophenol oil. For a contaminated activated carbon matrix, direct treatment was less effective, and the reduction of PCDDs/PCDFs to concentrations less than 1 ppb was better achieved by first extracting the carbon matrix with a solvent and then treating the extract NFESC and EPA have been jointly developing the BCD process since 1990. Data from the Koppers Superfund site in North Carolina are inconclusive regarding technology performance because of analytical difficulties. There have been no commercial applications of this technology to date. The BCD process has received approval by EPA's Office of Toxic Substances under the Toxic Substances Control Act for PCB treatment. Complete design information is available from NFESC, formerly NCEL and NEESA. Predeployment testing was completed at Naval Communications Station Stockton in November 1991. The research, development, testing, and evaluation stages were planned for Guam during the first two quarters of FY93. A successful test run with 15 tons of PCB soil was conducted in February. 6. Source: Marks, Peter J., Walter J. Wujcik and Amy F. Loncar, October 1994. REMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE, SECOND EDITION. DOD Environmental Technology Transfer Committee. NTIS No. PB95-104782. Reproduced for the Bloomington, Indiana PCB Superfund Sites Bulletin Board with the permission of USAEC, SFIM-AEC-ETD, APG, MD. Supplemented by MVA Consulting, Inc. Based on communication with technology vendors, EPA technical personnel and project managers, and the following documents: US EPA, November 1994. Superfund Innovative Technology Evaluation Program Technology Profiles, Seventh edition, EPA/540/R-94/526. US EPA, 1994. Innovative Treatment Technologies: Annual Status Report, sixth edition. (Summarizes Superfund decisions and actions through end of 1993.) Other references noted within this file are listed in the comprehensive reference file on this BBS. The entries in the reference file are organized by topic and by author. **********************************************************