Performance evaluation of resin wafer electrodeionization for cooling tower blowdown water reclamation

Abstract

The complicated nexus between water resource and energy consumption poses the problems of water scarcity, safety, affordability and carbon emissions. In the industrial and commercial buildings, the cooling tower is an inevitable system and has been considered to contribute water-energy consumption. Therefore, the high energy efficiency of water recovery technology should be practically developed to minimize the freshwater usage with lower energy consumption. In this study, a robust ion-exchange resin-wafer electrodeionization (RW-EDI) technology was used to demonstrate the desalination of cooling tower blowdown wastewater. Immobilizing the conventional ion-exchange resin into porous material between compartment can enhance ion transportation and significantly reduce the service labor for assembling and maintenance. The removal efficiency for blowdown water reclamation using RW-EDI was evaluated along with energy consumption, productivity, and current efficiency by investigating the key operating parameters including applied voltage and superficial velocity. The experimental design was based on the response surface methodology to statistically elucidate the optimal conditions. Results show that the energy consumption was 0.28 kWh m− 3 and productivity 23.4 L h− 1 m− 2 with around 90% removal of hardness to meet the standard of make-up water for blowdown water reclamation.