[Performance and Membrane Fouling Properties in an Anaerobic Membrane Bioreactor for Salty Wastewater]

In the research, an anaerobic membrane bioreactor (AnMBR) was used to treat simulated salty organic wastewater, and the effect of salinity on reactor performance and membrane fouling properties was investigated. The results indicated that when the influent salinity increased gradually but was lower than 9.1 g·L^-1, the reactor ran stably and the effluent performance was good. When the salinity increased to 10 g·L^-1, the COD removal-efficiency, gas production, and methane content decreased significantly; meanwhile, the sludge concentration, sludge volume index (SVI), soluble microbial products (SMP), and extracellular polymeric substance (EPS) levels became elevated at first and then declined with the rising salinity. The system developed compact flocs and a high settling ability. The hollow fiber membrane module was run for three cycles in 118 d. The membrane operating cycle was extended from 31 d to 48 d with the increasing salinity, which favored the control of membrane fouling. SEM-EDX analysis results revealed that there were similar crystalline substances in the film membrane foulants, and Na, Mg, Al, Si, Cl, K, Ca, and Fe were the main inorganic elements. Excitation emission matrix (EEM) analysis results demonstrated that proteins and humic acids were the main components of the organic membrane foulants.