Superfund Innovative Technology Evaluation (SITE)
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Geotech, Inc. - Cold Top Ex-Situ Virtification SystemInnovative Technology Evaluation Report
A Superfund Innovative Technology Evaluation (SITE) technology demonstration was conducted in February and March 1997 to evaluate the potential applicability and effectiveness of the Geotech Development Corporation (Geotech) Cold Top ex-situ vitrification technology on chromium-contaminated soils. The demonstration was conducted using the vitrification furnace at Geotech's pilot plant in Niagara Falls, New York.
Chromium-contaminated soil from two state Superfund sites in the Jersey City, New Jersey area was collected, crushed, sieved, dried, mixed with carbon and sand, and shipped to the Geotech pilot plant. The SITE demonstration consisted of one vitrification test run on soil from each site. During each test, solid and gas samples were collected from various locations in the Cold Top system and analyzed for several chemical and physical parameters. In addition, process monitoring data were recorded. During the demonstration, the Cold Top system treated about 10,000 pounds of soil contaminated with trivalent and hexavalent chromium and other metals.
One primary and five secondary objectives were identified for the SITE demonstration. The primary objective was to develop test data to evaluate whether waste and product streams from the Cold Top vitrification system pilot plant were capable of meeting the U.S. Environmental Protection Agency (EPA) Resource Conservation and Recovery Act (RCRA) definitions of a nonhazardous waste, based on the stream's leachable chromium content. Secondary objectives were to determine the following: (1) partitioning of chromium and hexavalent chromium from the contaminated soil into various waste and product streams; (2) the ability of the vitrified product to meet New Jersey Department of Environmental Protection (NJDEP) criteria for use as fill material (such as road construction aggregate); (3) the system's ability to meet applicable compliance regulations for air emissions of dioxins, furans, trace metals, particulates, and hydrogen chloride; (4) uncontrolled air emissions of the oxides of nitrogen, sulfur dioxide, carbon monoxide, and total hydrocarbons from the vitrification unit; and (5) projected operating costs of the technology per ton of soil.
Observational demonstration results showed that the Cold Top system vitrified chromium-contaminated soil from the two New Jersey sites, yielding a product meeting RCRA toxicity characteristic leaching procedure (TCLP) standards. From soil excavated at one of the New Jersey sites, the system yielded a potentially recyclable metallic product referred to as "ferrofurnace bottoms" that also met the RCRA TCLP chromium standard. Demonstration results also showed that the chromium content of the vitrified products did not differ significantly from that of the untreated soils, but that the baghouse dusts were higher in chromium content than the untreated soils. Hexavalent chromium concentrations in the untreated soil were generally not detected (reduced at least two to three orders of magnitude) in the vitrified product and ferrofurnace bottoms. The hexavalent chromium concentration in the baghouse dust was about the same as that in the untreated soil.
Results of emissions modeling indicate that the concentration of metals in stack emissions depend on soil characteristics, the APCS, and detection limits of various analytes. Analysis of operating costs indicates that Cold Top treatment of chromium-contaminated soil, similar to that treated during the SITE demonstration, is estimated to cost from $83 to $213 per ton, depending on disposal costs and potential credits for sale of the vitrified product.
The results of all sample analyses and quality assurance and quality control data from the SITE demonstration were evaluated with respect to the project objectives specified by the quality assurance project plan (QAPP). The conclusions of the demonstration are being reported as observational, meaning that although the authors feel the conclusions are supported, some data are not statistically valid at the levels specified in the original data quality objectives.