Study On The Performance And Sludge Characteristics Of A Strengthen Circulation Anaerobic Reactor Treating Municipal Wastewaer

In this experiment,the self-developed SCAR was used to treat the simulated municipal wastewater,and the feasibility of anaerobic biological treatment of municipal wastewater and the operational characteristics of the reactor were studied.The main topic of this research are as follows.The effects of hydraulic retention time?HRT?and upflow velocity(V_up)on the performance of the reactor were investigated during the experiment.The particle size distribution,the maximum specific methanogenic activity?SMA?,coenzyme F420 and extracellular polymeric substances?EPS?were investigated during the operation of the reactor.And the distribution characteristics and evolution of microbial community under different time and space conditions were analyzed by high throughput sequencing.The results of the experiment demonstrated that the HRT for 6h could be regarded as the key parameters of dominating the efficient operation of SCAR reactor,in which condition the COD removal efficiency was above 75%.The coenzyme F420 and the maximum specific methanogenic activity?SMA?of granular sludge increased with the increasing of the VLR,and the EPS contents,especially TB-EPS in the granule sludge also increased obviously.The results showed that COD removal rate increases with the increase of V_up,but when V_up was beyond a certain range,the increase rate of COD removal rate was small or even decrease,and the effluent sludge flocs and the water content of SS were more.HRT = 6h,V_up = 3.89 m · L-1 can be regarded as the best condition for reactor operation.The content of S-EPS increased with the increase of V_up,and the content of LB-EPS and TB-EPS in the opposite trend except HRT = 12 h.In addition,when V_up increased,the PS of TB-EPS in granular sludge increased significantly at HRT = 12 and HRT=4 h.In the analysis of ?-diversity of bacteria,it was found that the diversity of microorganisms was different under different HRT conditions,but there was no significant difference in microbial diversity in the reactor space under the same HRT condition.the diversity and abundance analysis of bacteria community showed that,under the different load conditions,the predominant bacteria in the phylum distribution of the bacteria were Proteobacteria,Firmicutes,Bacteroidetes and Chloroflexi,And the proportion of the dominant species was more than 85%.In the Classes distribution of the bacteria,the number of species was small and the abundance of dominant bacteria varied greatly.In the genus distribution of bacteria,the number of species was different,and the distribution of dominant bacteria was not uniform.In the analysis of ?-diversity of archaea,the diversity of microorganisms under different HRT conditions was found to be quite different.The diversity of microorganisms in the reactor space distribution at lower load conditions?HRT=12h?had a big difference,but at a relatively high load conditions?HRT=6h?had a small differences.In addition,when the HRT was shortened,the species of archaea in the bottom and top of the reactor decreased,especially at the bottom.The diversity and abundance analysis of archaea community showed that Euryarchaeota was the dominant species in the phylumdistribution of archaea,accounting for more than 89% of the total archaea.Methanomicrobia was the dominant species in the Classes distribution of archaea,accounting for more than 80% of the total archaea except sample a1?66.14%?.In the distribution of genus Archaea,the differences of the dominant species between different samples were significant.The dominant archaea include Methanosaeta,Methanosarcina,Methanolinea and Methanomassiliicoccus,which are the dominant species.