Primary study on the bio-remediation of oil contaminated soil of Karamay oilfield

The optimal launch conditions were investigated by study on the bio-remediation of oil contaminated soil of Karamay oilfield, and the changes of soil physicochemical properties, microbiological characteristics, oil components were also studied during the soil bioremediation. The results showed that the main factors of bioremediation were the bacteria dosage, moisture content and manure dosage. The optimal launch conditions were as follows: microbial dosage per 1 kg oil polluted soil of 200 mL, moisture content of 15%, chicken manure of 20 g, wheat bran of 50 g and surfactant of 30 mL. The oil degradation rate reached 56.31% after 75 d bioremediation under above condition. The physicochemical properties and microbiological characteristics of the soil were significant changed at different stages of bioremediation, the urease, dehydrogenase activities decreased and catalase activity increased. The four components separation test and simulation distillation experiments for oil sample from oil polluted soil after bioremediation showed that the degradation ability order of the hydrocarbon components by microbe from high to low was saturated, aromatic, resin and asphaltene. The short chain n-alkanes (C12-C14) were first degraded by bacteria, which could not be detected after 70 d degradation. The GC peak shape of n-alkanes changed greatly, from symmetrical to left slow, right steep, and the relative content of isoparaffin increased, the base line of GC was significantly elevated.