Predominant Bacteria Evaluation By Fluorescent In Situ Hybridization In A Gravel Contact Oxidation Reactor

Excess biomass produced within the processes is creating environmental challenges due to expensive ultimate disposal options, such as landfills and/or incineration. It is necessary to develop an innovative technology for removal of more organic loading by enriching the activated biomass and meanwhile, reducing the amount of excess biomass.In order to achieve excess sludge reduction, physical, chemical and biological methods were discovered. It has been certificated that the simplest and most economy method without secondary pollution is biological method. According to the micro-organisms metabolism and the relationship among them, the hypotheses of excess sludge reduction include energy uncoupling, death and lysis of bacteria, micro-fauna's predation and the dominating slow growers. It is particularly important to study microbial diversity, predominant bacteria and its growth dynamics for excess sludge reduction.Five bacteria genus,β-proteobacteria,ε-proteobacteria, bacteroides, Leptothrix discophora and Xanthomonas, were detected by fluorescence in situ hybridization (FISH) technology in biological gravel contact oxidation reactor (BGCOR) and a conventional activated sludge reactor (ASR) used as comparison, subjected to illustrate the probable functions of the micro-ecosystems structure, as well as the dominated bacteria species and number to excess sludge reduction in BGCOR.In order to indicate the predominant bacteria correlated with excess sludge reduction, the predominant bacteria community is analyzed in detail. Meanwhile, it is important for improving the efficiency of organic pollutants degraded by bacteria.The central limit theorem and the maximum likelihood estimation theorem were used in bacteria amount count. The results illustrate thatε-Proteobacteria in BGCOR is 3.5 times more than ASR, and the bactericides in BGCOR is 2 times more than ASR. The unique bacteria community structure in biofilm and porous of carrier seems to be a function of excess sludge reduction in BGCOR. Further, more detailed studies of selected physiological groups, including the investigation of their activity, their metabolism relationship with substrate and each other, are necessary to link their survival environment physical and chemical variability.