ABSTRACT
Anaerobic membrane bioreactor (AnMBR) for sewage treatment was operated for 650days with the decrease of temperature from 25°C to 10°C. At higher temperature >15°C, COD removal was above 94% while sewage treatment efficiency and relevant CH4 production decreased below 15°C. The effluent COD at 10°C was 134mg/L at HRT of 16h. Moreover, low temperature can result in a higher membrane fouling rate due to the microbial self-protection behavior in coping with the temperature decrease by releasing soluble microbial products (SMP) and extracellular polymeric substances (EPS). The contribution of pore blocking to membrane fouling caused by protein from SMP and EPS increased from 17% to 45% and that of cake layer decreased from 81% to 53% at 25°C and 15°C respectively. The inhibition to hydrolysis and acidification process was responsible to the decrease of sewage treatment at lower temperature.
Subject(s)
Bioreactors , Sewage , Anaerobiosis , Membranes, Artificial , TemperatureABSTRACT
Influence of cellulose as suspended solid (SS) on the performance of submerged anaerobic membrane bioreactor (SAnMBR) was evaluated at 25°C using two types of synthetic sewage (SS contained or not). During the 110days operation, COD and BOD removal, CH4 gas recovery and cellulose accumulation were investigated in detail. The influence of cellulose as SS in sewage on the SAnMBR performance was not significant at HRT longer than12h and 65-72% of the influent COD was recovered as methane gas at HRT of 12h. At HRT of 6h, the quality of effluent got worse and the accumulation of cellulose was found in reactor. 16S rRNA analysis revealed that the microbial diversity distribution including Archaea and Bacteria changed due to the addition of SS in sewage and specific microbe for cellulose degradation such as Proteobacteria was detected. Sludge in SAnMBR could acclimate to characteristics of sewage by self-adaptation.
