Research On The Relationship Of Microbial Community Structure And Membrane Fouling In Anmbr Under Different Temperature

Anaerobic membrane bioreactor more applications in high concentration organicwastewater treatment process, but in low temperature area is not widely used inmunicipal wastewater treatment process.On the other hand membrane fouling problemrestricts the development of anaerobic membrane bioreactor, although people throughdifferent methods to study the main reasons of membrane fouling, but microbialcommunity structure and metabolic product of research are rare.An anaerobic membrane bioreactor was run at a room temperature to investigatethe relationship between microbial community structure and membrane fouling.Changes in the microbial community structure of membrane surfaces were studied byterminal restriction fragment length polymorphism analysis (T-RFLP) technology. Therelationship between the microbial community structure and soluble microbialproducts (SMP), extracellular polymeric substances (EPS) were also investigated. Theresults showed that membrane fouling period was18d at a room temperature, and theremoval rate of COD was approximately93%. The succession of microbialpopulations made the concentration of microbial metabolites gradually increased andaccelerated the process of membrane fouling. The dominant microbial species ofmembrane surface were Raoultella, Owenweeksia when film pressure was slowlyrising. When the pressure rose steadily, the dominant bacteria changed intohongkongensis, Delftia acidovorans, Halothiobacillus neapolitanus. At last, themicrobe of bp78became the climax community. When the membrane fouling isthrough the slow rising period and steady rising period, the pressure and the diversityof microbial community structure showed a significant positive correlation. Whenmembrane fouling was in the rapid rising stage, top community appeared on thesurface of the membrane silk, and microbial community diversity decreasedsignificantly. At this point, the diversity of microbial community structure showedweakly related with the membrane pressure. The evenness of microbial community onmembrane surface increased firstly and then decreased as membrane pressure rose, andthe microbe continued to adhere on the membrane surface firstly, and then competedwith each other until the top community appeared. In the medium temperature state ofmembrane pollution cycle is about23d, the removal rate of COD is about90%,Microbial metabolites concentration as the succession of microbial population showed a trend of rising, speeded up the process of membrane pollution; Mixture ofmicroorganism advantage bacterium group for Halothiobacillus and Pirellula staleyi,and with the increase of membrane pressure in Cake layer, Halothiobacillus andPirellula staleyi gradually became the dominant fungi genera.