Beschreibung:
This study demonstrated the remarkable potential of electrolytic system type for industrial reverse osmosis concentrate (ROC) treatment on effluent quality and energy requirements. Following their individual system optimization, the required current density decreased from 20 mA cm −2 for the batch system during 4 h of electrolysis, to 5 mA cm −2 for a continuous-flow system (CFS) without effluent recirculation (CFS-A), and 3 mA cm −2 for a CFS system with a rear (CFS-B) or front (CFS-C) buffer tank for effluent recirculation ( R = 1). The effluent chemical oxygen demand and NH 4 + −N levels markedly decreased from 31 and 0.4 mg L −1 , respectively, in the optimized CFS-A system and 24 and 0.56 mg L −1 in the optimized batch system to 5.7−8.1 and 0.24−0.34 mg L −1 in the optimized CFS-B and -C systems. The optimized CFS-B and -C systems achieved the highest pollutant removal, treatment capacity, and energy efficiency, as well as the lowest effluent toxic organic byproduct levels; however, they exhibited elevated effluent perchlorate levels. The optimized CFS-C system was recommended for future engineering implementation because of the lowest effluent active chlorine species (ACS) level. The inherent mechanisms affecting effluent quality and energy savings included the homogeneous diffusion characteristic, the reutilization of long-lived ACS oxidants in electrolytic effluent, and the low flow rate into the electrochemical cell