Bioremediation of oil-contaminated soil by three strains of petroleum degrading and its kinetics

摘要

This paper is dedicated to the effect of adding high-efficiency hydrocarbon-degrading bacteria into the petroleum-polluted soil on its bioremediation process, with the soil in Yan an, north Shanxi as the research object. Three strains degrading crude oil separated from oil-contaminated soil through concentrated culture. The paper studied and appraised their physiological-biochemical features initially through experiments. In the biological recondition model experiment on petroleum contaminated soil, we added SY22, SY23, SY42 separately as well as their mixture to the soil samples. The research also left a control assay for contrast. This study evaluated all five treatments on the degradation of total petroleum hydrocarbons(TPH)in soil. In addition, the number of petroleum-degrading micro-organisms presented and microbial activity as indexed by the dehydrogenase assay were monitored. A 50-day's biodegradation experiment under natural mode showed that after the addition of highly petroleum -degrading bacteria, control, addition SY22, addition SY23, addition SY42, and addition three mixture had TPH decreases of 11%, 26 %, 65 %, 60 %, 38 %,respectively, the bacteria amount increased to 109. What's more, the quantity peaked its top twenty-two days later of a number notably higher than in origin soil. Instead of inhibition effect, it increased the number of bacteria. Each of the dehydrogenase activity in processing added with SY22, SY23, SY42 and their mixture was separately 2.54, 23.3, 14.8, 7.3 folds higher than that of the blank assay. Evidently, almost all kinds of microorganism in soil can be promoted in activity of their dehydrogenase after the addition of superior bacteria. Half -life of treatment added SY23 shorted to 32.7d.