Domestication of Oil-Degrading Strains and Bioremediation of Oil-Contaminated Soil in Daqing Oilfield

Oil-degrading strains were domesticated and enriched using the medium recycling method. Then the microorganisms were used in bioremediation of oil-contaminated soil from Daqing Oilfield, China. The laboratory study showed that the addition of enhanced microorganism and medium can make the oil degrading efficiency reach to more than 90% after 150 days degradation. The activity of the predominant microorganism could be measured by the test of TTC-dehydrogenase, which reached the maximum value at day 30 and then declined with the drop of oil content. The GC-MS analysis of the oil-contaminated soil showed that the most components in oil were among C10-C36. From the gas chromatograph analysis of the carbon chains during the degradation, every oil composition was degraded obviously after 150 days and the molecule chains longer than 28 C nearly disappeared. The field study in Daqing Oilfield was affected by air temperature and after 300 days treatment, 80-93% of degrading efficiency was obtained.