Analysis Of Microbial Diversity Of Biotrickling Filter In Municipal Wastewater Treatment Plants And Isolation Of Efficient Desulfurization Strains

In recent years, with the continuous expansion of city size, urban sewage treatment plants are settled in residential areas surrounded by malodorous gases generated in the sewage treatment process,which will not only affect the health of employees and working environment of the sewage treatment plant, but also bring serious harm to the normal life of the residents around. Therefore, the sewage treatment plant is imperative to configure the appropriate deodorizing process system.Biological air pollution control began in the1950s, initially with soil to govern sewage plants wrenching smell of gas. Due to the advantages of the biological air pollution control,which is economic,efficient and environmentlly friendly,it has been widely used.And a lot of research on the process, fillers and various elments affecting the processing efficiency (such as temperature, pH, nutrients, etc.)are carried out. Subject to the influence of various environmental factors, the growth of microorganisms in the processing system and the interaction between microbial population structure and microbiological and environmental factors are needed to be deeply studied, in order to adjust the operating parameters,improve process, and keep moderate growth of microorganisms,thereby improving the efficiency and performance of the the biological treatment of malodorous gases.In this paper, microbial diversity of Shanghai Minhang Water Purification Plant biological filter tank filler is studied using conventional microbial counts, clone library, molecular biology methods.And several efficient desulfurization bacteria are screened and identified in the research. The following conclusions:(1) Heterotrophic bacteria occupied the largest number in the the Biofilm.WIth the MPN counting method,it is showed that sulfur oxidation bacteria has the greatest number among ammonia oxidation bacteria, nitrite oxidation bacteria and sulfur oxidation bacteria. And the number of nitrite oxidation bacteria is larger than ammonia oxidation bacteria.(2) The microbial diversity of the bilfims in2#and3#biotrickling filter are different.Proteobacteria and Bacteroidetes are found in2#biotrickling filter,and Gammaproteobacteria bacteria is found in3#biotrickling filter as a main culture.(3)19desulfurization bacteria are purified from1#,2#,3#biological trickling filter.By comparing the sulfate rate, we can draw a highly efficient desulfurization The ability of the strains order J3, J10, J13,J7, J8, J9,j2, J1, J11, J17, J14, these desulfurizing bacteria in the process of desulfurization reaction the use of sodium thiosulfate and sulfate formation rate not less than0.0085g/(L·h).(4) By colony morphology observation and molecular biology techniques, the separated efficient desulfurization bacteria were identified. They are divided into four genera:genus Thiobacillus, Halothiobacillus, Pseudomonas genus, genus Dyella. There are three strains of sulfur bacteria, two strains of Halothiobacillus,4strains of Pseudomonas and two strains of Xanthomonas.(5) By the shake-flask experiments,the growth curve of the of J3(Halothiobacillus neapolitanus) is studied out, as well as the optimal culture conditions. It can be concluded that the optimum growth temperature range is25-30°C, optimum growth pH range of6.5-7.0.