Screening of Efficient Hydrocarbon-Degrading Strains and Study on Influence Factors of Degradation of Refinery Oily Sludge

Three kinds of bacterial strains, HJ-1, HJ-2, and HJ-3, were isolated by means of enrichment culture from oily sludge in Shengli oil field. HJ-1 was identified as Bacillus by primary test. The influence of seed age, oil concentration, microbial quantity experimental time, and pH on the degradation ability of the HJ-1 strains was investigated. The results showed that the oil reduction rate was 69.4% for the refinery oily sludge, and the conditions were as follows: 50 mL, pH 9, oil concentration 5 g·L-1 enrichment culture of crude oil, addition of 12 mL of strain HJ-1 at the seed age of 16 h, experimental time 6 days, then evaluate the fermentation of hydrocarbon-degrading strain HJ-1 in a shake flask. The influencing factors of pH, microbial quantity, glucose concentration, salt concentration, rotation speed, and temperature were also studied. The oil degradation rate of HJ-1strains rose from 78.6% to 82.0% for crude oil and from 69.4% to 77.4% for oily sludge from the refinery, as the fermentation bacteria solution was added into the oily sludge under the optimum conditions.