A review of anaerobic membrane bioreactors for municipal wastewater treatment with a focus on multicomponent biogas and membrane fouling control

Among the various anaerobic digestion technologies developed for wastewater treatment and resource recovery, the anaerobic membrane bioreactor (AnMBR) stands out as a viable alternative to traditional processes. However, the practical use of the AnMBR to treat a huge amount of low to moderate strength wastewater, like municipal wastewater (MWW), at ambient temperature, remains a challenge due to the membrane fouling issue and a low bioenergy recovery efficiency. In this review, the basics of the AnMBR process regarding membrane and bioreactor configurations are introduced. Then, the performance of the AnMBR with regard to pollutant removal and biogas production is discussed with special emphasis on analyzing the origin and fate of multicomponent biogas in the liquid-gaseous phases based on theoretical predictions and reported experimental results. A review of the studies on the mechanisms of membrane fouling is included together with an overview of the commonly used fouling control measures to support long-term sustainable AnMBR operation. Lastly, the technical challenges in enhancing AnMBR development from a number of different perspectives are pointed out. Applying AnMBR for the treatment of low-strength wastewater should be further optimized to enhance the techno-economic feasibility for full-scale operation, and more research attention should be given to the redirection of organics and nutrients to achieve a more economical process with improved environmental benefits.