Lead and Zinc Smelting Wastewater Treatment and Reclamation by Coagulation-Flocculation-Sedimentation, Ultrafiltration and Reverse Osmosis Technique

Abstract

The typical smelting wastewater is with characteristics of high concentration of TDS, conductivity, heavy metal ions, and low concentration of COD. The ultrafiltration (UF) and reverse osmosis (RO) is an attractive technology to reclaim and reuse this kind of wastewater. In this work, Coagulation-flocculation-sedimentation (CFS) and multi-media filter (MMF) was used as the pretreatment processes. UF, RO and concentration RO (CRO) processes was applied as the advanced treatment processes to reclaim the smelting wastewater. To enlarge the recovery of RO and CRO units, the influences of increasing the feed temperature by waste heat from the smelting plant and the feed pressure by change the operating frequency of the high pressure pumps were investigated. The optimize operation parameters of RO and CRO units were obtained. To understand the operation CIP cycle time of UF, RO and CRO membrane units in a long term operation, the trans-membrane pressure (TMP) and permeate flux difference were investigate. Good system operation stability, permeate flux recovery after CIP and qualified treated water were obtained in the recommend operation parameters. The results of this work can benefit to the designing of reclaiming the smelting wastewater by UF-RO-CRO approach within the Lead and Zinc smelting industrial application.