Investigation on two integrated membrane systems for the reuse of electroplating wastewater

A pilot study was done on a nanofiltration (NF)-reverse osmosis (RO) and RO-NF integrated membrane system about the feasibility of membrane for electroplating rinse wastewater treatment in concentrate stage configuration. Nickel sulphate solution was used as a synthetic wastewater. Water recovery, metal rejection and specific entropy production (SEP) were investigated under different operation pressure, feed temperature and feed concentration. The results showed water recovery of RO-NF system was more than 10% higher than NF-RO system but the SEP was 14.47% lower than NF-RO system. The detailed analysis on economic cost and environmental impact of two systems was conducted based on a certain operation condition. Results indicated that the cost of RO-NF system was 0.46 $/m(3), which was lower than NF-RO system, and the prevention cost of RO-NF system was 11.46% lower than NF-RO system. Generally, RO-NF system was better than NF-RO system.