Electrodialysis for desalination of brackish groundwater in coastal areas of Korea

Electrodialysis (ED) with ion-exchange membranes was applied for desalination of salted groundwaters from three places in coastal areas in Korea. The ED system produced high quality of permeate. However, substantial resistance built-up was identified in one particular groundwater sample. Possible causes of the fouling were sought for better understanding of brackish water desalination. Several model samples with different ion composition, that is, Na2SO4, MgSO4, CaSO4 at the same conductivity condition, that is, 1,200s/cm were tested to understand effects of monovalent and divalent ions on water quality and increases in resistance of the ED system. In addition, organic matter concentrations were compared in the sampled groundwaters. The ED performance of the three model solutions showed similar tendency in operation time and current curve and did not explain the discrepancy of ED performance of the groundwater. Dissolved organic carbon concentration results implied that organic matter in the groundwater played an important role in ED operation.