Superfund Innovative Technology Evaluation (SITE)
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Canonie Environmental Services, Inc.'s Low Temperature Thermal Aeration (LTTA® ) Process thermally desorbs organic compounds from contaminated soil without heating the soil to combustion temperatures. The technology removes organic contaminants from contaminated soils into a contained air stream, which is extensively treated to collect or thermally destroy the contaminants. A direct-fired rotary dryer heats an air stream which, by direct contact, desorbs water and organic contaminants from the soil. The process soil is quenched to reduce temperature and mitigate dust problems. The processed soil is then discharged into a stockpile. The hot air stream that contains vaporized water and organics is treated by one of two air pollution control systems. One system removes the organic contaminants from the air stream by adsorptoin on granular activated carbon (GAC) and includes the following units in series: (1) cyclones and baghouse for particulate removal; (2) wet scrubber for acid gas and some organic vapor removal; and (3) GAC adsorption beds from organic removal. The transportable system consists of six major components assembled on nine flat-bed trailers and five auxiliary support trailers. The LTTA® system was demonstrated at a confidential abandoned pesticide mixing facility in western Arizona in September 1992. During the demonstration, the LTTA® system treated site soils contaminated primarily with seven pesticides: toxaphene; 4,4'-dichlorodiphenyltrichloro-ethane (DDT); 4,4'-dichlorodiphenyldichloroethane (DDD); 4,4'-dichlorodiphenyldi-chloroethene (DDE); dieldrin; endosulfan I; and endrin. Based upon the SITE demonstration, the LTTA® (1) can process a wide variety of soils with differing moisture and contaminant concentrations; (2) can remove VOCs from soil to below detection limits; (3) can substantially decrease SVOC concentrations in soil; (4) can remove pesticides from soil to below or near detection limits (removal efficiencies range from 82.4 to grater than 99.9 percent); and (5) did not produce dioxins and furans.