Increasing water recovery rate of membrane hybrid process on the petrochemical wastewater treatment

Abstract

Abstract The objective of this work is to increase the recovery of water through a Reverse Osmosis + Electrodialysis Reversal (RO-EDR) hybrid process, where the EDR is used to recover water from the reject produced by the RO technology. The wastewater used in the experiments was collected in a petrochemical industry, located in southern Brazil, after conventional treatment (biological and stabilization ponds). The RO tests were carried out in a pilot equipment, having a spiral membrane module, with a membrane area of 7.2 m2. For the EDR tests, it was used a pilot equipment, with 300 ion-selective membranes, with a total membrane area of 28.8 m2. The results show that the application of EDR technology was adequate for the treatment of the RO reject, obtaining a removal efficiency above 90% for chlorides and alkalinity. The recovered water comply with standards for reuse in cooling towers. In addition, the full recovery of the treated water was satisfactory, reaching a recovery rate of 87.3%, turning the EDR-RO hybrid process as a prominent one.