Brackish water desalination using electrodeionization reversal

Abstract Electrodeionization reversal (EDIR), which is electrodeionization using periodic changes of polarities, was examined in drinking water production from brackish water in this study. Using the characteristic curves of the EDIR process combined with the demineralization rate and energy consumption, the appropriate applied voltages were determined to be 11.0, 13.0 and 19.0 V for the feed total dissolved solids (TDS) of 2000, 3000 and 4000 mg L −1 , respectively. The performance of the EDIR system, was affected by polarity reversal periods, which were determined to be 3.0 h or 2.0 h for different feed TDS. For feed water with TDS in the range of 2000–4000 mg L −1 , varying voltage 11–19 V should be applied to ensure the demineralization rate to be not less than 90.0% at a constant water recovery of 75%, and the energy consumption was 1.04, 1.95 and 3.71 kWh m −3 for feed TDS of 2000, 3000 and 4000 mg L −1 , respectively. The concentration of ions in dilute product water did not exceed the permissible WHO standards and taste quality of the product water was good. Thus, EDIR seems to be the economical desalination process for production of drinking water from brackish water.