Isolation Of High-efficiency Oil-degrading Bacteria In Emulsion Wastewater And Its Application In Basic Research

Steel industry discharges plenty of waster waters into the environment. Thewastewater is complex in water quality, chemical stable, difficult to degrade and itcontains a lot of oil emulsion. Traditional physical and chemical method can not get abetter removing result, so the biological method is more often combined with physicaland chemical method. The microorganisms in sludge was not the dominant species.Therefore, to screen and cultivate the dominant species of microorganisms to degradethe oil emulsion in steel industry wastewater is of great importance.Present study focused on the degrading bacteria used to degrade the oil waste wateremulsified by SDS. The SDS was selected as emulsion in this study. Method of enrichand cultivate the degrading bacteria was established. The influence of degrading speedand pathway induced by temperature and pH were investigated. Communitycharacteristic of this bacterial were analysis by RFLP. The conclusions of the researchwere shown as follows:(1) SDS was choose from5kinds of surfactants, after standing30s and10min,the emulsification rates of SDS were79.87%and32.36%. In the course of theexperiment, the detection of30s emulsification rate using secondary extraction, andthe detection of10min emulsified using an extraction rate. In a certain range,30s and10min emulsion emulsification rates are increased with the rise of temperature,30semulsification was easier influenced by temperature than10min. As a result28℃wasselected as the experimental control temperature.(2) A screen and cultivate means of a rolling oil degrading microbial was establish.Under the condition of25~28℃, pH7.5~8.5, DO2~5mg/L, the microorganismwith a certain ability to efficiently degrade the oil was filtered out with the increasing ofthe oil after26d of cultivation. During the culture, pH, DO, SV and SVI and otherindicators are regular changed. The best degrading effect of bacteria was occurred at pH8.2, temperature28~33℃. The microorganism obtained could degrade the in oilemulsion adequately. After72h treatment, the degradation rate was above60%.(3) The RFLP method was used to analyzed the characteristics of degrading bacteria.16S rDNA clone library contains84clones dividing into19OTUs and itscoverage is78.57%. Shannon index (H ’) was2.67, Simpson index (D) is0.90, richness(R) was4.06, evenness (E) is0.91. Constructed clone library of efficient degradationbacteria bacterial contains most of the population, which represent that the sample wasof microbial diversity.(4) The sequencing results was contrast with known16S rDNA. The highestsimilarity strains distributed in8gates,11classes,13orders,15families and15genera,of which, the proteobacteria was dominant (52.38%). This results are similar with thedomestic and foreign research that the Proteobacteria was the most dominant bacteria.Also, a strain that was similar to Thermoleophilum album (similarity of100%) wasfounded. They can degrade different kinds of oils and present a better prospect in oilemulsion degradation.