GEOTECH DEVELOPMENT CORPORATION
(Cold-Top Ex Situ Vitrification of Chromium-Contaminated Soils)
Geotech Development Corporation (Geotech) claims that the Cold-Top ex situ vitrification technology coverts quantities of contaminated soil from a large number of particles into an essentially monolithic, vitrified mass. According to Geotech, vitrification will transform the physical state of contaminated soil from assorted crystalline matrices to a glassy, amorphous solid state comprised of interlaced polymeric chains. These chains typically consist of alternating oxygen and silicon atoms. It is expected that chromium (both trivalent and hexavalent) can readily substitute for silicon in the chains. According to Geotech, such chromium should be immobile to leaching by aqueous solvents and, therefore, biologically unavailable and nontoxic.
This technology has been successfully used to process municipal solid waste incinerator ash, fly ash or bottom ash, asbestos-containing materials, and various slag materials. The developer claims that the technology can also be used to incorporate heavy metals, such as cadmium or chromium, rendering them unleachable by the toxicity characteristic leaching procedure (TCLP).
This technology was accepted into the SITE Program in December 1994. The SITE demonstration will occur during the second phase of a two-phase New Jersey Department of Environmental Protection-funded research project that is being coordinated by the New Jersey Institute of Technology, Hazardous Substance Management Research Center.
A bench-scale study in 1994 established the performance of the process based on leachability of chromium and the concentration of free hexavalent chromium in the glass product. The study included the collection and subsequent analysis of soils from nine chromium-contaminated sites in northern New Jersey. The soils were analyzed for total chromium and total hexavalent chromium; the soils also underwent TCLP analyses for chromium. The concentrations of hexavalent chromium were as high as 4,800 milligrams per kilogram in untreated soil. The results of the evaluation indicated that concentrations of chromium in the leachate from TCLP analyses were generally less than 1 milligram per liter (mg/L), and that the concentrations of chromium in all samples were below the regulatory threshold concentration of 5 mg/L.
During the SITE demonstration, 3-ton samples from the Colony Diner site and the Liberty State Park site in Jersey City, New Jersey will be vitrified. Cold-Top ex situ vitrification will attempt to render hexavalent chromium unleachable, and destroy other trace organics found in soil from the New Jersey sites. In addition, the vitrified product will be tested for potential reuse in road construction. The SITE demonstration is expected to occur in 1997.
EPA PROJECT MANAGER:
Marta K. Richards
U.S. EPA
National Risk Management Research
Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7692
Fax: 513-569-7676
TECHNOLOGY DEVELOPER CONTACTS:
Thomas Tate
Geotech Development Corporation
1150 First Avenue, Suite 630
King of Prussia, PA 19406
610-337-8515
Fax: 610-768-5244
William Librizzi
Hazardous Substance Management
Research Center
New Jersey Institute of Technology
138 Warren Street
Newark, NJ 07102
201-596-5846
Fax: 201-802-1946