Analysis On Microbial Community Structure Of SUFR Reactor And Isolation Of Phosphorous Accumulating Organisms

Nitrogen and phosphorous element are the limiting and main factors made eutrophication of water body, removal of nitrogen and phosphorous element is the primary ways to prevent eutrophication of water body. Nowadays, biological nitrogen and phosphorus removal from wastewater is an important water pollution control technology. In order to optimize the construction and operating parameters of biological dephosphorizing and denitriding processes, it is important to investigate microbial community structure of the processes. As a new biological dephosphorizing and denitriding process, SUFR has the quality of effectively removing nitrogen and phosphorous from wastewater. The microbial community structure in the reactor certainly has close relationship with the function of the reactor. In this paper, we used ERIC-PCR fingerprinting to investigate the variation of microbial community structure during the start-up running process of the reactor, and the microbial community structure of the reactor at low temperature. PAOs(Phosphorous accumulating organisms) were isolated from the activated sludge of the SUFR reactor.It was demonstrated that: non-functioning bacteria reproduct vigorously after a pause of the reactor. In the beginning time, the reactor cannot effectively removing the nitrogen and phosphorous from wastewater. After a period of mediating, the non-functioning bacteria were gradually replaced by functional bacterial groups, the reactor begin to work steadily. In the 9th day, removal efficiency of TN and TP respectively reached 80.7% and 91.3%. In the following days, the reactor work steadily, there was little variations of microbial community structure, Cs matrix values were between 70% to 90%.Analysis on the microbial community structure of activated sludge in SUFR reactor at low temperature. The results indicated that microbial community structure in SUFR reactor distributed in a high level of diversity at low temperature, and predominate bacterial community was obvious. When the temperature was 5℃, removal efficiency of TN and TP still reached 72.35% and 93.28% respectively, which maintained the normal function of SUFR reactor. At this period, the diversity of bacterial community decreased and the number of predominant bacteria become poor, even so, the single predominant bacteria maintained the function of the reactor. Along with the temperature clime up, normal bacterial community resumed which enhanced the function of the reactor.PAOs(Phosphorous accumulating organisms) is an important kind of bacteria in the process of biological nitrogen and phosphorus removal. By excessively absorbing phosphorous than their own need, the PAOs remove the phosphorous from wastewater. Members of several different bacterial divisions of microorganisms have been proposed as PAOs. These include the Actinobacteria,Lampropedia,Microlunatusphosphovorus,Rhodocyclus et al. In this study, four different kinds of bacteria were isolated which have the characteristic of anaerobic phosphorus release and aerobic phosphorus absorb. The four different kinds of bacteria were named as PAO-12,PAO-23,PAO-44 and PAO-48. PAO-12 has the best quality of phosphorous removal, the efficiency of phosphorus removal could be 6.907mg/l. Sequence analysis of 16S rDNA identifies that the four bacteria belong to Microbacterium(PAO-12), Bacillus (PAO-23), Tsukamurella (PAO-44) and Tsukamurella (PAO-48).The bacteria of these four genus hadn't been reported as PAOs. Data presented here add further supports to the view that EBPR may be mediated by different microbial populations under different conditions of process configuration and wastewater composition. The perfect technological characters of SUFR provide different kinds of PAOs ecological environment to survive, which exert function of removing phosphorous from wastewater efficiently.