This report presents cost and performance data for the application of on-site incineration at the Times Beach Superfund site in Times Beach, Missouri. A rotary kiln incinerator was operated from March 1996 through June 1997 as part of a remedial action. The contaminant of concern at the site was 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).
The Times Beach site served as a central incineration facility for 27 TCDD-contaminated sites across the state of Missouri. Soil and debris at these sites were contaminated with TCDD in the 1970s by waste generated in the production of hexachlorophene by a pharmaceutical and chemical company. This waste was mixed with waste oil and sprayed on roads as a dust suppressant by a private firm.
The contaminated debris from the 27 sites included home insulation, furniture, flooring, carpet, and mattresses; scrap metal; and tree stumps and brush. Contaminated soil contained rocks, asphalt, gravel, and sawdust . The geometric mean of TCDD concentrations measured during the remedial investigation was 79 µg/kg.
In 1990, EPA and the State of Missouri entered into an agreement with the Responsible Party (RP). A Record of Decision (ROD) signed in September 1988 established a destruction and removal efficiency (DRE) of 99.9999% for TCDD.
The RP conducted remedial activities including the operation of the rotary kiln incinerator. The incineration system used at Times Beach was comprised of a solid waste feed system; a countercurrent, controlled-air, rotary kiln with an oxygen-enhanced burner; a secondary combustion chamber (SCC); a wet gas cleaning system (GCS); and a treated material handling system .
Soil and debris were collected in bags, drums, and boxes, and transported to the Times Beach incinerator. To prepare the feedstock, soil was mixed with lime to reduce moisture content and debris was shredded to an acceptable size for the incinerator. Prepared material was fed to the incinerator by an enclosed conveyor.
Resulting ash from the incinerator was removed and cooled with water, while off-gas was drawn into the SCC. The SCC was a down-fired steel shell that provided further combustion of contaminants in the off-gases. Both the incinerator and SCC were fueled by natural gas.
Treated gas was then drawn into the GCS, which consisted of a quench contactor, a gas conditioner, two Hydro-Sonic® scrubbers, and a vane separator. The GCS cooled the gas from the SCC and was designed to remove particulate matter, metals, and acid gases before discharge to the atmosphere. Ash collected from the incinerator and GCS was sampled and analyzed; if it met the treatment criteria it was landfilled on site. Ash that failed to meet criteria was re-incinerated.
During its 16 months of operation, the incinerator processed approximately 265,000 tons of contaminated material. Treatment performance and emissions collected during this application indicate that all performance standards and emissions were achieved.
The actual cost for remediation
using the incineration system was approximately $110,000,000.
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