2단계 연속배양과 분해세균에 의한 2,4,6-trinitrotoluene (TNT)의 제거

Degradation of 2,4,6-trinitrotoluene (TNT) by a white rot fungus lrpex lacteus and activated sludge was investigated in two step bench-scale continuous stirred tank reactors. Inoculum for the first reactor was I. lacteus which already showed a high degradation activity for TNT, and activated sludge from a sewage treatment plant was used as an inoculum for the second reactor. The two-step continuous culture experiment was conducted for 150 days using synthetic feed containing different levels of TNT (10 to 300 mg/L) at room temperature. When a hydraulic retention time of 36 h was maintained, the highest TNT removal rates were 1.66 mg/L/h in first reactor and 0.82 mg/L/h in second reactor during the period of 71~100 days from the start-up. These results indicate the application potential of two-step continuous reactor system for treatment of TNT-containing wastewater. Several TNT-degrading bacteria were isolated from the second reactor, and their biodegradation capabilities were examined. TNT was completely disappeared within 6 hours of further incubation when 100 mg/L of TNT was added into 1-day pregrown C1 bacterial culture. However, this bacterium was unable to use TNT as a sole source of carcon. TNT degration might be accomplished by a cometabolic process using glucose as a growth substrate.