Reclaiming Municipal and Industrial Wastewater using Combined Membrane Bioreactor and Reverse Osmosis

Gippsland Water is implementing the Gippsland Water Factory (GWF) to reclaim 35,000 m3/day (9.2 mgd) of municipal and industrial (pulp and paper) wastewater to a quality matching the pristine quality of the existing raw water supply. Bench- and pilot-scale testing supported multi-criteria analysis to select the most sustainable approach, which consists of separate treatment in parallel treatment trains of the municipal and industrial wastewater using membrane bioreactor (MBR) technology followed by reverse osmosis (RO). Primary treatment is incorporated into the municipal treatment train, while the industrial treatment train includes anaerobic pretreatment. Industrial MBR effluent will be pre-treated by ozone followed by biological activated carbon (BAC) prior to RO to reduce fouling caused by non-biodegradable organics in the industrial MBR effluent. The industrial anaerobic pre-treatment unit is also being used to stabilize primary and waste activated sludge prior to dewatering. Anaerobic pre-treatment of industrial waste helped minimize MBR membrane fouling. Results demonstrate that additional treatment is needed to reclaim the difficult to treat industrial wastewater due to RO membrane fouling. Organics levels must be reduced to allow a chloramine residual to be maintained, as well as to control fouling organics. The project is being implemented using an alliance model. Membranes were selected using monetary and non-monetary criteria. Stage 1, which will reclaim the municipal wastewater, is currently under construction and Stage 2, which will allow reclamation of the industrial wastewater, is being planned. Bench- and pilot-scale testing to refine the Stage 2 facilities is continuing.