Bioremediation of Soil Contaminated with Multiple Petroleum Products by Soil Microorganisms

摘要

The purpose of this study is to investigate the biodegradation characteristics of the BTEX and TPH by petroleum-degrading bacteria that were separated from soil contaminated with petroleum products, and the optimum biodegradation conditions according to the type of soil texture. The optimum culture conditions for petroleum-degrading bacteria showed 1～2 g/L of cell concentration, 500 mg/L and below of substrate concentration, 30℃ of culture temperature and pH 6～8. The removal efficiencies of benzene, toluene, ethyl-benzene and xylene in soil contaminated with multiple petroleum products by the mixed gasoline- and diesel- degrading bacteria were 100.0%, 89.2%, 76.4%, 60.8% after 9 days respectively, and thus they were clearly distinguished from the control group. The removal efficiencies of TPH for 37 days by the mixed gasoline- and diesel-degrading bacteria were 76.7% at 1.0 L/min of air flow rate and 89.4% at 5.0 L/min for sandy clay loam, and 87.2% at 0.25 L/min and 91.7% at 2.0 L/min for sandy loam, and they were higher than the control group (42.3%) and proved the petroleum-degrading bacteria are available. The removal efficiency was increased along with the higher air flow rate and permeability but the preventive action for the reduction of soil moisture contents and the volatilization of BTEX according to the increase of air flow rates was needed. The removal rate of TPH for sandy loam that is a typical soil texture in South Korea showed above 90.0% at 2.0 L/min and below of air flow rate.