The Development Research On The Repairment Of Microbial Agents About Ground Crude Oil Contaminated Soil

With the problem ofenvironmental pollution become more and more worse, the problem of crude oil contaminated soil has become increasingly serious either.This paper is based on screening、isolating and building efficient compound bacterium strain in order to prepare for the efficient composite microbial remediation agent. From the experiment can obtain the best biodegradation conditions、best preparation process and key factors, which ensured the remediation of ground crude oil contaminated soil had the best effect. The conclusion is as follows:(1)Selected four strains from the ground crude oil contaminated soil which can degree the oil in the soil were named as DB-1, DB-2, DB-3 and DB-4 respectively. From the preliminary identification of colony morphology and physiological and biochemicalexperiments, it can be concluded that the DB-1 belongs to Pseudomonas sp., DB-2 belongs to Bacillus sp., DB-3 belongs to Rhodococcus sp., and DB-4 belongs to Pseudomonas sp.(2)Under the experiment of the effect on the different conditions to the degradation rate can come to a conclusion that the best culture time was nine days, which the degradation rate was 45.3%. When the oil concentration was 500mg/L, the effect was best as the maximum degradation rate reached 65.4%. The maximum degradation rate was 73.8% when the p H value was 7. When the inoculums was 6%,the maximum degradation rate was 63.2%. When the concentration of Na Cl was 2%,the degradation rate was 68.3%.In peptone as N source, the highest degradation rate was 72.3%,take yeast powder as auxiliary N source,the maximum derradation rate can reached 69.1%.(3)By four strains inoculated with different proportion of four factors and three level orthogonal test could be obtained that the best degradation effect for agent composite was A3B3C1D2,from which the composite degradation rate can be as high as 82.7%.To the best preparation technology of composite inoculants for the three factors and three levels of orthogonal test,the optimum conditions of preparation temperature is 40°C,the best p H value was 8,the carrier(wheat bran,straw) mass ratio of the percentage is3:1,the crude oil degradation rate reached the maximum72.1%.(4)Indifferent add conditions on microbial remediation inocula and dehydrogenase activity test, compound inoculants on oil content is 2% for the oil degradation in soil was the highest. Comprehensive dehydrogenase activity test investment plus the amount of oil lowering effect of 10% compound microbial inoculum best was 74.7%. The maximum oil drop rate of fortieth days was 73.4% when combined with dehydrogenase test.