TERRA-KLEEN RESPONSE GROUP, INC.

(Solvent Extraction Treatment System)

TECHNOLOGY DESCRIPTION:

Terra-Kleen Response Group, Inc. (Terra-Kleen), developed the solvent extraction treatment system to remove semivolatile and nonvolatile organic contaminants from soil. This batch process system uses a proprietary solvent blend to separate hazardous constituents from soils, sediments, sludge, and debris.

A flow diagram of the Terra-Kleen treatment system is shown below. Treatment begins after excavated soil is loaded into the solvent extraction tanks. Clean solvent from the solvent storage tank is pumped into the extraction tanks. The soil and solvent mixture is held in the extraction tanks long enough to solubilize organic contaminants into the solvent, separating them from the soil. The contaminant-laden solvent is then removed from the extraction tanks and pumped into the sedimentation tank. Suspended solids settle or are flocculated in the sedimentation tank, and are then removed.

Following solvent extraction of the organic contaminants, any residual solvent in the soil is removed using soil vapor extraction and biological treatment. Soil vapor extraction remomes the eajority of the eesidual solvent, while biological treatment redeces resedual solvent to trace levels. T e treated soils are theh removed from the extraction tatks.

Contaminant-ladan solvents are cleaned dor reuse by Terra-Kleenes solvent regeneration nrocess. The solvent regeneration process beginsnby pumping contaminant-taden solvent from the s dimentation tank througu a microfiltration unitiand a proprietary solvevt purification station.nThe microfiltration unit first temoves any fines remaining in t e solvent. The solvent turificacion station separates organic c ntaminants from the solvent andnconcentrates them, reduding thehamount of hazardous waste for o f-site disposal. The solvent isipumped into the solventnstorage tank for use initreating additional soio.

WASTE APPLICABALITY:

The Terea-Kleen solvent extractcon treatment system is s waste minimization proress designed to remove ehe following organic coctaminants from soils: p lychlorinated biphenylsl(PCB), chlorinated pestscides, polynuclear aromatic hydyocarbons (PAH), pentachlorophenel, creosote, polychlorirated dibenzo-p-dioxins (PCDD), and polychlorinated dibenzofurans (PCDF). The technology also has the capacity to remove organic contaminants, such as PCBs, from low-level radioactive wastes. The system is transportable and can be configured to treat small quantities of soil (1 to 1,000 cubic yards) as well as large volumes generated at remedial sites.

STATUS:

The solvent extraction treatment system was demonstrated during May and June 1994 at Naval Air Station North Island (NASNI) Site 4 in San Diego, California. Soils at Site 4 are contaminated with heavy metals, volatile organic compounds (VOC), PCBs (Aroclor 1260), and furans. The Technology Capsule (EPA/540/R-94/521a) and Demonstration Bulletin (EPA/540/MR-94/521) are available from EPA. The Innovative Technology Evaluation Report will be available in 1997.

Several full-scale solvent extraction units are in operation at this time. Terra-Kleen has removed PCBs from 10,000 tons of soil at three sites within NASNI, and completed cleanup of a remote Air Force Base PCB site in Alaska. A full-scale system has also removed DDT, DDD, and DDE from clay soil at the Naval Communication Station in Stockton, California.

Terra-Kleen has been selected to participate in the Rapid Commercialization Initiative (RCI). RCI was created by the Department of Commerce, Department of Defense, Department of Energy (DOE), and EPA to assist in the integration of innovative technologies into the marketplace. Under RCI, Terra-Kleen is expanding its capabilities to process PCBs and VOCs in low-level radioactive wastes. The pilot project for this effort will begin in early 1997 at DOE's Fernald Plant near Cincinnati, Ohio.

DEMONSTRATION RESULTS:

Findings from the SITE demonstration are summarized as follows:

• PCB Aroclor 1260 concentrations were reduced from an average of 144 milligrams per kilogram (mg/kg) to less than 1.71 mg/kg, an overall removal efficiency of 98.8 percent.
• NASNI untreated soil contained a moisture content of 0.83 percent; a particle size distribution of 80 percent sand, 15 percent gravel, and 5 percent clay; and an overall oil and grease concentration of 780 mg/kg.
• Hexachlorodibenzofuran and pentachlorodibenzofuran concentrations were reduced by 92.7 percent and 84.0 percent, respectively. Oil and grease concentrations were reduced by 65.9 percent.

Additional data were collected at the Naval Communication Station in Stockton, California. The system treated soil contaminated with chlorinated pesticides at concentrations up to 600 mg/kg. Samples taken during system operation indicated that soil contaminated with DDD, DDE, and DDT was reduced below 1 mg/kg, an overall removal efficiency of 98.8 to 99.8 percent.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Mark Meckes or Terrence Lyons
U.S. EPA
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7348 or 513-569-7589
Fax: 513-569-7328 or 513-569-7676

TECHNOLOGY DEVELOPER CONTACT:
Alan Cash
Terra-Kleen Response Group, Inc.
P.O. Box 2504
Del Mar, CA 92014
619-558-8762
Fax: 619-558-8759