Effects of feed wastewater characteristics and recovery rate on industrial wastewater reuse by reverse osmosis process

The rapid growth of industrial zones has increased wastewater generation and placed pressure on industrial water supplies. This study evaluated the performance, membrane fouling, and energy consumption of a lab-scale RO system at different wastewater sources and recovery rates for potential reuse. The results showed that the quality of after membrane bioreactor (MBR) effluent achieved higher permeate quality than that after physicochemical 2 (PC2), with overall removals of about 90 - 96% for EC, TDS, Ca 2+ , and total hardness, except for total Fe and color. As the recovery increased from 40 to 80%, removal efficiencies decreased slightly (≤5%), with the highest overall removal at 60%. The specific energy consumption (SEC) of the RO system when operating with after-MBR effluent was 0.96 kWh/m 3 —about 8% higher than that of after PC2 effluent—and decreased from 0.68 to 0.58 kWh/m 3 when the recovery rate increased from 40% to 80%. Furthermore, the membrane fouling index when operating with after-MBR effluent was 1.1 times lower than that after-PC2 effluent and increased with increasing recovery. Therefore, the quality of feed wastewater and recovery rate should be considered when RO systems are applied effectively to wastewater reuse purposes. • MBR effluent produced higher RO permeate quality than after-PC2. • Over 90% removal achieved for EC, TDS, Ca 2+ , hardness, Fe, and color. • Optimal RO performance occurred at a 60% recovery rate. • MBR–RO system enables sustainable industrial wastewater reuse.