Forward-osmosis anaerobic-membrane bioreactors for brewery wastewater remediation

Since most of the water used for brewing becomes wastewater, the reduction of wastewater streams is of great importance for the brewing industry. Anaerobic membrane bioreactors incorporating forward osmosis membranes (FO-AnMBRs) could provide an energy-efficient solution for the treatment of brewery wastewater, while recovering water and simultaneously producing biogas. The start-up period of two lab-scale FO-AnMBRs fed with real (R_real) and synthetic (R_synth) brewery wastewater was assessed and compared to continuous stirred tank reactor operation without membranes. During reactor start-up, the hydraulic retention time (HRT) of the reactors was reduced from 20 to 2.5 days while increasing the organic loading rate. The CH₄ production of R_synth and R_real increased up to nine-fold when the membranes were integrated, demonstrating the principle that FO-AnMBR can be used for brewery wastewater treatment. However, process stability decreased with decreasing HRT, possibly due to shear stress and the inadequate C/N ratio of the wastewater.