Bioremediation of petroleum contaminated soil

Two kinds of polyacrylamide(HPAM)-degrading bacteria S1, S2, which can use HPAM as only nitrogen source and the sole carbon source, were isolated from petroleum-contaminated soil of Daqing Oilfield. The bioremediation for treating petroleum contaminated soil by immobilized microorganisms can improve the effect on biodegradation for pollutants in oil fields and reduce the loss of bacteria. The degradation ability of five kinds of embedding immobilization methods on soil pollutant was investigated. The experimental results showed that the immobilized microbial granules, which used polyvinyl alcohols (PVA) and sodium alginate as coagulant, activated carbon as coagulant-support, exhibited good mechanical strength, operated easily, be not breakable and low cost. Experiments results showed that after treatment using this kind of immobilized microbial granules, the HPAM concentration declined from 500 mg.L-1 to 102 mg.L-1 in 48 hours. The degradation rate of HPAM reached 79.6%. At the same time crude oil content decreased from 733.21 mg.L-1 to 9.5 mg.L-1. These immobilized microbial granules can remove 98.7% oil from the petroleum-contaminated soil in 48 hours.