Study On The Microbiological Of Controlling Effect To MBR Membrane Bio-fouling Of Operational Conditions

MBR has its unparalleled features in sewage treatment field. Membranefouling problem increases the running costs of the process and it limits itsdevelopment in real applications. One kind of common membrane pollutions is theirreversible membrane fouling which caused by microbial activities.In this study,two sets of parallel A/O-MBR reactors were used to analyse the changing situationand the succession of microbial community structure and the correlation betweenmicrobial community evenness and membrane pollution process from the fivestages of speeding membrane fouling up and slowing membrane fouling downrespectively.The changing situation of membrane fouling cycle under different operationalconditions of MBR was explored. Also the production and accumulation of EPSwere detected during the different membrane fouling processes. The results showthat changing operating conditions have an important inffluence for changingmembrane fouling cycle and increasing EPS concentrations in cake layer as well asSMP in A/O-MBR system. The goal that membrane fouling cycle had beingspeeding up and slowing down, respectively was achieved.. The accumulation ofEPS concentrations was about8～10mg/gMLSS at end of membrane pollutioncycle. With TMP getting rising, the concentration of SMP tended to its maximumvalue. Membrane pollution process may get exacerbated by the accumulation ofSMP.During the process of membrane fouling, microbial community structure is in arelatively stable state. Microbial community succession is in a state of regularity.Affected by the operational conditions, the dominant species of mixed liquor duringthe process of the membrane fouling rate speeding up under five differentoperational running stages is Xanthomonas sp., Nitrospira, Thiothrix Eikelboomiiand so on. The dominant species of cake layer is Thiothrix Eikelboomii, γ-Proteobacterium., Cytophaga sp., Rhizobiales Bacterium, Anaeromyxobacter,Zoogloea Ramigera, Saprosiraceae and so on. The dominant species of membranesilk surface is Cytophag sp., Gamma Proteobacterium, ZoogloeaRamigera, Comamonadaceae and so on; The dominant species of mixed liquor during theprocess of the membrane fouling rate slowing down under five different operationalrunning stages is Saprospiraceae, Nitrospira, Comamonas sp., RhizobialesBacterium, Deltaproteobacterium, Burkholderia sp.and so on. The dominant speciesof cake layer is Myxobacterium, Thiothrix Eikelboomii, Rhizobiales Bacterium,Anaeromyxobacter and so on. The dominant species of membrane silk surface isNitrospira, Gamma Proteobacterium, Saprospiraceae, Rhizobiales Bacterium,Anaeromyxobacter and so on. Operational conditions have a decisive influence formicrobial community succession process.The microbial community evenness of cake layer and membrane silk surfacegets regularly during the membrane fouling process. Uniformity of microbialcommunities gets worse, the membrane fouling rate gets lower, and even reacheszero membrane pollution. Microbial communities tend to be more uniform,membrane fouling turn to more severe and the effluent flux decreases.