Demineralization of geothermal water reverse osmosis (RO) permeate by electrodeionization (EDI) with mixed bed configuration

• Demineralization of RO permeate of geothermal water by EDI
• The mixed bed configuration of EDI
• The effect of applied potential on demineralization
• The effect of membrane thickness on demineralization
• The effect of process parameters on system performance

For demineralization, the reverse osmosis (RO) permeate of geothermal water was further treated with an electrodeionization (EDI) system where the ion exchange resins were filled in the mixed bed configuration into the central compartment. The effect of the process parameters such as applied voltage and membrane type on the quality of the product water was examined. The results show that the conductivity of the product water increased when a high potential is applied to the system. When a voltage of 25 V was applied to the system, the conductivity of feed water decreased from 15 μS/cm to 0.6 μS/cm. At 40 V of applied voltage, conductivity of feed water increased from 15 μS/cm to 28 μS/cm. The thickness of the membrane was also an important parameter for the quality of product water obtained. When the thin membranes (Neosepta-AMX and Neosepta-CMX) were used, the conductivity of the product water increased from15 μS/cm to 24 μS/cm.