Evaluation of Capacitive Desalination Technology for Drinking Water Treatment in Rural Alaska

One emerging technology with potential for application in rural Alaska and other small communities is capacitive desalinization. This technology utilizes electrodes made from activated carbon fabric coated with a conductive material. When these electrodes are layered into a capacitive cell and a DC power supply is applied, the individual electrodes are charged. Dissolved ions in the water are attracted to the electrode of opposite polarity, thus removing the dissolved ions from solution. These dissolved ions accumulate in the electrode pore structure and are discharged as a concentrated waste stream by shorting the electrodes to ground. Capacitive desalination systems are solid state devices with few moving parts and no requirement for chemical addition. These characteristics suggest that this technology may have the potential for application in rural Alaska. This paper summarizes the preliminary results from a study conducted with an Electronic Water Purifier (EWP) capacitive desalination system manufactured by Sabrex, Inc., on water from Goose Lake (Anchorage, Alaska) and Oscarville, Alaska. Experiments were performed to evaluate the ability of the EWP system to remove the high concentrations of natural organic material (NOM), dissolved inorganics, and organics present in the source waters.