ABSTRACT
Many communities and sites throughout the US and the world have a need for improving water quality but have no access to electrical grid power. Reclamation set out to develop a solar photovoltaic-powered electrodialysis reversal (PV/EDR) desalting system that could be used at these remote sites and communities. Electrodialysis (ED) was chosen because it can use the DC power provided by photovoltaic arrays. Electrodialysis is a membrane separation process that utilizes DC current to move and separate dissolved minerals in water. Cations and anions are displaced by an electric field through transfer-selective membranes leaving demineralized product water. The separation of minerals occurs in individual membrane units called cell pairs, which consist of an anion transfer membrane, a cation transfer membrane, and two spacers. The complete assembly of cell pairs and electrodes is called the membrane stack. The solar pumping system has been operating continuously since September 1992 and has pumped almost 900,000 gallons with only minor interruptions for well maintenance.
