Application of Anaerobic Membrane Bioreactor to the Treatment of Low-Strength Municipal Wastewater

An anaerobic membrane bioreactor (AnMBR) was employed for the treatment of low-strength municipal wastewater in this study. The membrane filtration performance and pollutant removal efficiency were investigated. A series of measurements, i.e., three dimensional excitation-emission matrix (EEM) analysis, gel filtration chromatography (GFC), Fourier transform infrared (FTIR) analysis, characterization of membrane foulant components, were systematically carried out. Test results showed that the AnMBR could achieve good chemical oxygen demand (COD) removal. Total nitrogen (TN) was also eliminated by 25-30% by the reactor. Under temperature above 20°C, the AnMBR could be successfully operated for 86 days without any cleaning at membrane flux 5-10 L/(m² h). It was also found that the membrane fouling was mainly caused by the sludge cake layer formed on membrane surfaces. The major components of foulants were sludge particles; however, the biopolymers, such as proteins, polysaccharides, humic substances, etc., especially organic matters with high molecular weight (MW), also played an important role in the membrane fouling.