Study On Using Integrated Anaerobic Fluidized Bed Membrane Bioreactor For Sewage Treatment

With the rapidly development of economic and gradually increasing of urbanpopulation, China has faced the shortage of water and energy resource. A amount ofmunicipal sewage emission seems to be a significantly thorny issue of the low carbonsystem, therefore, sewage recycling is one of the present promising for experts andscholars. This research was to make municipal sewage up to the low-carbon standardemission and recover energy efficiently by the new integrated Anaerobic Fluidized-bedMembrane Bioreactor （iAFMBR）.The new iAFMBR reactor takes the membrane into the anaerobic fluidized bed andseparates the main part by cylindrical partition. Sewage would be purged by thecombined action of membrane and the tube. This study considered the effect of differentHRT and temperature on the removal efficiency of sewage including the removal oforganic pollutant、the accumulation of volatile fatty acid and the production of energygas.After two months’ start-up period it is showed that the system have reached a stableoperation with the efficiency of organic removal and the production of the energy gasunder the8hours’ HRT at35℃,the efficiency of COD removal is about75%with theeffluent below100mg.L^-1and the methane production is maintained at more than400mL/d.The change of HRT has a great impact on the running state of this iAFMBR reactor.When the HRT is more or equal to6hours, the efficiency of organic pollutants removalis almost above74%, and the accumulation of volatile fatty acid is low; when the HRTturned down to4hours, the removal rate of COD decreased and the volatile fatty acidaccumulated more obviously. During the HRT is6hours the highest volume of methanegas has conversed by every unit of influent CODs with the average daily production is1013.3ml. At this time, the rate of energy recovery is highest and the membrane foulingcycle is24d. When the membrane fouled the main microbial metabolites is EPS in themixture and filter mass, by the way, the content of protein is higher than that ofpolysaccharide. In addition, membrane fouling would be reduced by dosing GAC intothe inner cylinder.Temperature changes have a significant impact on iAFMBR processingperformance. With the temperature getting down the removal rate of the organicpollutants would be decreased, the effluent mount of volatile fatty acid would beincreased and daily production of energy gas would be reduced. At a low temperatureindex changes high, however, iAFMBR still shows some advantages compared with the conventional anaerobic process based on its fluidized bed system and inner cylinderfunction. In addition, the highest volume of methane gas has conversed by every unit ofinfluent CODs at25℃, at this time, the membrane fouling cycle up to25d.The cost of building this sewage treatment plant is1.15times for a A₂O process iftake this iAFMBR into an actual engineering, but the cost of running would bedecreased by24.7%, and save83.3%room for construction. In addition, the effluentused for irrigation would be back to262,800yuan while the energy gas productionvalues of45,700yuan per year. In total, iAFMBR process release the shortage of waterand energy resource, makes a value of economic and have a extensive wide uses onsewage treatment in the long run.