Anaerobic and Aerobic Degradation of Aromatic Hydrocarbons Using In-Situ Bioreactors at an Unleaded Gasoline Spill Site

摘要

Unleaded fuel has leaked from an underground storage tank and spread 100 M radially in the saturated and unsaturated zone under a clay cap of soil. The estimated amount of fuel spilled in the saturated zone is 10,000 L. Four bioreactors have been installed in the ground at the site, one dedicated to aerobic and three to separate anaerobic conditions: methanogenic, nitrate- reducing and sulfate-reducing. The bioreactors are stainless steel cylinders filled with contaminated zone soil and contain approximately 84 L. Contaminated groundwater is pumped through each bioreactor in an upward flow. Influent and effluent levels of the aromatic hydrocarbons benzene, toluene, ethylbenzene, 1, 2,4- and l,3,5-trimethylbenzene, and m/o/p-xylene were examined. In addition, preliminary studies have suggested anaerobic degradation of these aromatic hydrocarbons, although the biochemical regime remains to be ascertained.