Research on submerged membrane bioreactor and its membrane fouling in treating dioscorea zingiberensis wastewater

A membrane bioreactor (MBR) process was used to treat the dioscorea zingiberensis wastewater. The wastewater treatment station had put in operation for 8 months. The normal sludge concentration in MBR was more than 8000 mg/L. The results showed that the removal rates of pollutants were high, and the MBR could better resist impacting loading. But the COD concentration of effluent was not very low, so the wastewater should be treated by anaerobic or anoxic process at fist. The MBR process had the good effect to removal rate of NH₃-N, indicating that the long sludge retention time in MBR made that nitrobacteria accumulated. Terminal restriction fragment length polymorphism (T-RFLP) was used to analyze the microbial community structure on the surface of membrane in order to study the biofouling of membrane of MBR. The results indicated that the biofilm formation induced the membrane fouling and that some specific phylogenetic group of bacteria, the Pseudomonas sp. probably played a major role in leading to the severe irreversible membrane biofouling.