Performance and Economic Evaluation of Resin Wafer Electro-Deionization for Cooling Water Blowdown Desalination

Sustainable water management is the critical issue in dealing with circular water economy and water scarcity, for further overcoming drought in the future. Industrial cooling tower systems consume about 70% of total fresh water use, especially in semiconductor industries of Taiwan. The development of high energy efficiency technology for cooling water blowdown reclamation can minimize the water and carbon footprint, which is beneficial to the environment and the economy. In this study, resin wafer electro-deionization (RW-EDI), utilizing immobilized conventional ion exchange resin in porous material to enhance ion mobility, was used to demonstrate the desalination of cooling water blowdown from an incineration plant in north Taiwan. With a feed total dissolved solids (TDS) concentration of 900 mg/L, RW-EDI exhibits an excellent performance; more than 99.75% of salts can be removed. The energy consumption was 0.26–0.49 kW · h/m3, with productivity increases from 9.1–15.9 L/(h m2) of the desalination process under various applied voltages. For economic evaluation of the RW-EDI process, the levelized cost of water was from 0.31 to 0.43 USD/m3, where the material costs were far greater than the operational energy cost. Briefly, it can be concluded from the results that the RW-EDI process is a crucial component in the portfolio of water supply options by providing impaired-water reclamation.