Qualitative And Quantitative Analysis Of Functional Microbes In Simultaneous Denitrification And Methanogenesis System

Simultaneous denitrification and methanogensis system (SDM) was finished by two different types of functional microorganisms in physio-biochemical characteristics. The changes of operating parameter affect bioactivity observably. It is highly significant to link the change of microbial ecological information and the variations of reactor performance.In this assay, effects of COD/NO3--N, organic loading rate (OLR) and nitrogen loading rate (NLR), hydraulic retention time (HRT), nature of carbon source, nitrogen species (nitrite/nitrate) and cultivating way on SDM performance and microbial community structure were studied by building batch assay and continuous flow experiment provided sole-carbon-source using molecular biology methods amplifed ribosomal DNA restriction analysis and quantitative polymerase chain reaction. The main conclusions are as follows:(1) In batch assay, the effect of nitrogen species (nitrite/nitrate) on SDM and methanogens were studied. The results showed that the variation of methanogen structure was same in the environment of same concentration of NO3--N/NO2--N. The inhibited strength on methanogenesis increased and the inhibited duration of methanogenesis become longer with the concentrations of NOx-N increase.(2) In continuous flow experiment, the effect of COD/NO3--N, HRT, OLR and NLR on SDM and methanogens were investigated. It was confirmed that the sugar-feed system was more tolerant than the acetate-feed system and the structure of methanogenic community in sugar-feed system was more stable than this in acetate-feed system when COD/NO3--N, HRT, OLR and NLR changed.(3) With sucrose and sodium acetate as the carbon source, keeping the concentrations of carbon source constant, the effect of COD/NO3--N on microbes were studied. The results showed that when the concentrations of carbon sources were constant, the numbers of bacteria increased and the numbers of archaea decreased with the decrease of COD/NO3--N.(4) The effect of HRT on archaea in SDM with a single carbon source was investigated. The results showed the number of archaea increased and the the relative abundance of different methanogens almost unchanged with the decrease of HRT.