An overview of anaerobic membrane bioreactors: Current developments, fouling problems, and future prospects

Abstract

Anaerobic membrane bioreactors (AnMBRs) have become more popular in industrial wastewaters treatment since they are a less expensive alternative to aerobic procedures. AnMBRs are effective in chemical oxygen demand (COD) decreasing and favored the conversion of organic matter into a useful energy in form of biogas. AnMBRs generate effluent with less sediments and nutrients, and free of pathogens all these advantages in a small footprint. The biomass retention by the membrane increases the AnMBRs performance in case of substrates with high inhibitory or toxic concentration compounds. However, other problems persisted, such as membrane fouling and flux reduction at the membrane outlet, not forgetting ineffectiveness at lower temperatures as AnMBRs tend to operate best at high temperatures as the case of mesophilic or thermophilic growth. High dissolved and suspended particles, oil, fats, transmembrane pressure “TMP”, and flux have all been described as key contributors to membrane fouling, depending on the effluent strength. Lowering hydraulic retention time, removing nutrients, removing micro-pollutants, establishing a quantifiable mass and energy/economic balances, and including recovery of dissolved methane with high efficiency are all areas where more research is needed. The applications, limits, and future prospects of AnMBRs are summarized, and appraised in this brief review, with an emphasis on industrial wastewaters treatment. In addition, the AnMBRs are related to other wastewater treatment systems, which currently on used in the market.