Screening Of Low Temperature Resistant Bacteria And The Study Of Disposal In Mimic Wastewater Treatment

According to the National Statistics.more than80%of the sewage was treated by the biological activated sludge technology and its derivative products.Because this kind of technology mainly depends on the bacterium strains which have their optimum reaction temperature,so they are greatly affected by environment temperature.When the temperature is below10℃.their activity decrease sharply.So,in the winter of China,the efficiency of sewage processed equipments which depended on biological activated sludge technology were affected seriously.In this study,we screened8low temperature resistance bacterial strains who can live at4℃from the4-8℃environment of winter.By cultivated at15℃100rpm,we tested these strains’efficiency of process high concentration sewage.6days later,we found that the strain B2had the highest efficiency (87%),while the Y7strain had the lowest efficiency (63.4%).All the screening strains were mixed according to their own sewage process efficiency,then we tested the sewage process efficiency of these combinations strains in high concentration sewage.The highest efficiency was80%and the lowest efficiency was73.6%.Although the efficiencies of combination strains was lower than some pure strains,but they waved slightly.So we thought the combinations strains were more fit for sewage process than pure strains in actual environment.we cloned the genes related to fatty acid dehydrogenation enzyme from those8screening strains by molecular biology technology,and then analysis these genes’ evolution relationship by bioinformatics methods.We revealed the activity amino acid His114,Glulll,Glu76,His200,Glul97and Glul64which combined by iron ion in Flavobacterium psychrophilum。 Further,we found the HRRHH、HNFHH activity His region which combined by iron ion,which is consistent with the HxxxxH,HxxHH,HxxHH activity His region found in other species.For the application of screened stains,we simulated the actual sewage aeration process by homemade10L reaction pool,which drumming gas by electromagnetic air pump and fixing the bacterium using dimension elastic material of polyolefin and aldehyde fibers。When the average reaction temperature is15℃and after6days process,the combination of the third mixed bacterium and the material number2had the best performance.Its COD degration efficiency was70.9%and phenol removal rate was92%which was much higher than other combinations.After the analysis of the sewage process effects of single-factors,we confirmed that the combination and the third mixed bacterium and the material number2is the best combination for sewage process.At the20℃environment,we analysis the influencing factors in the sewage process of the best combination. When aeration, the COD degradation rate was91%after2days,and nearly reached to100%after3days.At the same time,the phenol degradation rate also reached to94.7%.The result was much better than without aeration.Even the aeration reaction pool which only has the material number2,its COD and phenol degradation rate also has a great improved.After simulating the actual sewage process for the best combination (the third mixed bacterium and the material number two),we found it has the best performance at20℃.Even in the15℃,the degradation for COD and phenol can reach70.9%and92%respectively.All these result showed the feasibility application of this combination in the actual sewage process.Conclusion:we screened8low temperature resistance bacterial strains who can grow at4℃.By cultivated at15℃,we tested the sewage process efficiency of these sceened strains in high concentration sewage,the maximun process efficiency was86%,The highest efficiency of mixed bacteria was80%and relatively stable.Screening and studied the significant effect of the combination of themixed bacterium3and the material2in wastewater treatment,for its practical application in wastewater treatment to lay the foundation.