Microcosm experiments to enhance the bioremediation of a No.2 fuel oil-contaminated soil

Abstract

Soil microcosm experiments were conducted to identify soil amendments which enhance the biodegradation of a No. 2 (diesel) fuel in soil. Microcosm amendments in Phase 1 included yeast extract, acetate, methane, and activated sludge. Combinations of these amendments resulted in 16 different treatments. Phase 2 soil microcosms contained combinations of methane and methanotroph additions resulting in four different treatments. Gas chromatography was used to determine the time and treatment-dependent concentration of C12-C18 n-alkanes during Phase 1 and, C14-C19 n-alkanes during Phase 2. Results from Phase 1 indicated that the most extensive biodegradation occurred in methane and activated sludge-supplemented microcosms. Acetate and/or yeast extract inhibited biodegradation by soil and/or activated sludge microorganisms. Addition of methane relieved inhibition by these amendments. Methane and/or methanotroph additions to Phase 2 microcosms did not enhance biodegradation relative to unamended microcosms. In general, n-alkanes longer than n-C12 were equally degraded in soil microcosms.