Potential of electrodialytic techniques in brackish desalination and recovery of industrial process water for reuse

Abstract

Large demands for water in industry and consumer markets have led to the development of seawater desalination plants worldwide. Electrodialysis allows the removal of ions at a much lower specific energy consumption than pressure-driven systems and holds the potential to move the desalination industry to greater water yields, lowering the degree of water wasted and energy required for separations. This study investigates the use of traditional electrodialysis as well as electrodeionization for the removal of contaminant ions from brackish water as well as samples from industrial sources. Results indicated that conventional electrodeionization can successfully remove ion contaminants from brackish water at specific energy consumptions of approximately 0.9–1.5kWh/m3 water recovered with high water productivity at 40–90L/m2h. Ion-exchange resin wafer electrodeionization showed greater promise with specific energy consumption levels between 0.6–1.1kWh/m3 water recovered and productivity levels between 10–40L/m2h. From these results, electrodialysis and electrodeionization have demonstrated viability as alternatives to pressure-driven membrane systems for brackish water desalination.