Anaerobic membrane bioreactors (AnMBRs) are to integrate anaerobic digestion with membrane separation, such as membrane bioreactors (MBRs). Anaerobic digestion (AD) is more sustainable than aerobic treatment processes (e.g. AS process) due to the lack of oxygen supply, less excess sludge production, and methane recovery. Despite of these benefits, the challenges of long SRT control and poor sludge settling in AD do not allow us to use AD for diluted wastewater treatment (e.g. municipal wastewater); in some cases effluent standards to industrial wastewater effluents are so strict that AD cannot meet the reinforced standards. Membrane enables us to easily control SRT and produce treated water lacking particles, which can facilitate AD application to diluted wastewater treatment.
We have operated submerged AnMBRs shown in the right figure. The feed and permeate production through membrane are synchronized with timed pump operation. The accumulated biogas and the bulk solution are recirculated into the reactor for scouring membrane. Reactor status is regularly monitored in terms of pH, temperature, daily biogas production, permeate production and trans-membrane pressure. Our group has worked on AnMBRs for treating municipal and food wastewaters. Main research themes are currently to understand dissolved methane behaviors in AnMBRs and characterize soluble microbial products (SMPs) and extracellular polymeric substances (EPS) of anaerobic microorganisms in AnMBRs.