Brewery wastewater treatment by anaerobic membrane bioreactor

The micro-brewery business has been subjected to a rapid growth within the last decade. Many brewers are seeking reliable on-site treatment methods because of expensive wastewater compliance bills. Anaerobic membrane bioreactors (AnMBR) can achieve a high quality effluent that is free of suspended solids and exhibit a great performance stability under loading shocks. To date, there have been limited studies on the performance of AnMBRs for brewery wastewater. In this study, a state-of-the-art AnMBR lab-scale system (supplied by GE Water and Process Technologies) was used to investigate the performance and capacity of AnMBR for the treatment of brewery wastewater. The system was subjected to a 230 days of continuous operation with both synthetic and real brewery wastewater at organic loading rates (OLRs), ranging from 3.5 to 11.5 kg COD/m³/day. During all tested OLRs, the AnMBR system demonstrated an excellent COD removal efficiency (>98%) and produced an effluent with a less than 300 mg/L COD concentration and a stable methane yield at 0.31 m³ ChVkg COD (35 °C). While the system demonstrated an excellent biological performance, it was found that the efficiency of the AnMBR was limited by membrane fouling, which reduced the membrane permeability and caused an unstable membrane filtration performance. The results showed that AnMBRs should be operated at an OLR below 6.5 kg COD/m³/day and a filtration flux of 7 L/m²/hour (LMH) to achieve a long-term stable membrane filtration for the treatment of brewery wastewater.