Temperature effect on bioremediation of diesel fuel contaminated clay

Bioremediation kinetics of a diesel fuel-contaminated heavy clay soil under simulated landfarming conditions was studied to determine the effect of temperature on the process. Experiments were run at 3, 10, 16 and 22 degrees C; maximum biodegradation rates in soil microcosms were measured by monitoring headspace oxygen concentration and 14CO2 evolution from the mineralization of 14C-octadecane. Gas chromatographic analysis of n-alkanes from biologically active abiotic and fresh unweathered soil samples indicated that abiotic losses increased at higher temperatures. The maximum amount of biodepletion was observed at 10 degrees C. The reduction in abiotic losses was offset by increased biodegradation and similar total n-alkane depletion over the 10 to 22 degrees C temperature range. The implication of this result is that overall n-alkane depletion will be similar irrespective of the temperature, as long as the landfarming operation occurs in the 10 to 22 degrees C range