A Study On Microbiology Of ASBR Reactor Treating Thermal Hydrolysis Sewage Sludge

Mesophilic and thermophilic ASBR(anaerobic sequencing batch reactor ) dealing with thermo-hydrolyzed sewage sludge was investiagted in the paper.On the stage of start-up and of different loads in two ASBR,the operating results were discussed.The bacterial and archaea community structures were examined in the ASBR reactors by DGGE(Denaturing Gradient Gel Electrophoresis ) as the main means.The study on quick start-up of the mesophilic and thermophili ASBR indicated that:(1) using sequencing-batch operation mode,quick-start could be achieved in the mesophilic ASBR reactor in 52d.In stable stage,the average removal efficiencies of TCOD and SCOD of the mesophilic ASBR which dealing with thermo-hydrolyzed sewage sludge were 94.2% and 89.2%respectively.Results of DGGE and SEM showed that micro-organisms changes had taken place in the start-up stage of mesophilic ASBR.There were 4 kinds of predominated bacteria and 4 kinds of predominated archaea in the stable stage,most of which were rods and cocci.(2) using sequencing-batch operation mode and by the method of gradient increased temperature,quick-start could be achieved in the thermophilic ASBR reactor in 131d.In stable stage,average removal efficiencies TCOD SCOD of the thermophilic ASBR that dealing with thermo-hydrolyzed sewage sludge were 63.8%and 83.3%respectively.Analysis of DGGE and SEM indicated that micro-organisms changes had taken place in the start-up stage of thermophilic ASBR reactor.There were 3 kinds of predominated bacteria and 5 kinds of predominated archaea,which were rods and cocci. Methanosarcina(Methanosarcina) was one of the dominant strains.The organic loading rates of mesophilic and thermophili ASBR were improved gradually from 1.050kgCOD/m³Â·d,2.098kgCOD/m³Â·d,4.196kgCOD/m³Â·d to 7.762kgCOD/m³Â·d,the micro-organisms characteristics were studied under different loads.The results indicated that, (1) micro-organisms in thermophilic ASBR were unitary,most of which were rod-shaped, especially brevibacterium;micro-organisms in mesophilic ASBR were relatively rich,which were cocci,rods,filamentous,spirillum and so on.(2) Analysis of DGGE indicated that mesophilic and thermophilic ASBR had there predominated bacteria respectively. Methanosarcina was one of predominated archaea in the mesophilic and thermophilic ASBR; in thermophilic ASBR,the predominated brevibacterium was Methanobacterium thermoau trophicum.(3) With the increasing of organic loading rates,EPS in mesophilic and thermophilic ASBR increased,and the change was greater than 50mg/1.Content of EPS changed meanwhile.Mesophilic and thermophilic ASBR sludge activities also increased by 1.1 times and 1.2 times.Methods of T-RFLP,FISH were also explored to examine the microbial communities in the mesophilic and thermophilic ASBR under loading 7.762 kg·m^-3·d^-1.The results indicated that biomass and species richness of mesophilic ASBR were larger than that of thermophilic ASBR.