New Integrated Processes for Treating Cold-Rolling Mill Emulsion Wastewater

Two new integrated processes, gas-energy-management (GEM)—electrochemical catalytic oxidation (ECO)—membrane bioreactor (MBR) and ultrafiltration (UF)—ECO—MBR, in industrial-scale test for treating cold-rolling mill emulsion wastewater with water quantity of 200 L/h to 3000 L/h were studied. The former was put forward firstly and the latter was applied initially in this field. The operation conditions and mechanisms of each module in the integrated processes were analyzed and the influences of operational parameters of two processes on chemical oxygen demand (COD Cr) removal efficiency were comparatively investigated. The test results showed that the ultimate water quality from the two processes after treatment could meet the requirement for reuse. However, the quality of effluent treated by GEM—ECO—MBR was more stable than that of UF—ECO—MBR.