A technique for remediating contaminated soil in-situ was investigated at laboratory scale. The objective of this investigation was to develop and validate low temperature oxidation for in-situ treatment of soils contaminated with heavy hydrocarbons. The basis for this process is conversion of hydrocarbon contaminants to a coke-like material using air heated to moderate temperatures (160 ℃ - 200 ℃). The intent is to reduce the mobility and toxicity of these contaminants. As applied in the field, contaminated soils would be remediated in situ, i.e., without excavation, using injection wells to introduce heated air to the contaminated soil. The method of investigation consisted of laboratory experiments in a plug flow reactor to determine the effect of various parameters on the treatment of contaminated soil samples. These parameters include; temperature, air flow rate, initial hydrocarbon concentration and initial water content. Five test runs of 14 days each were completed. Results were produced for each test run indicating conversion to coke and off-gas generated. Treated soil was analyzed for extractable hydrocarbon by extraction in toluene and for toxic compounds by TCLP. Toxicity was also evaluated by bio-assay using earthworms. It was demonstrated that hydrocarbons were substantially converted to coke and the soil toxicity was significantly reduced.
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