SODIUM-FREE ION EXCHANGE: PILOT TESTING INNOVATIVE ION EXCHANGE PROCESSES FOR ARSENIC REMOVAL

摘要

Pilot plant studies of two new ion exchange treatment processes, advanced ion exchange operations (AIXO) and indefinite brine recycling (IBR), were conducted with groundwaters in Scottsdale and Tucson, Arizona. These two processes make ion exchange a more practical treatment alternative for arsenic removal. The AIXO pilot plant successfully produced a finished water with <10 μg/L arsenate by accumulating the arsenate within the ion exchange columns for the 7,000 BV of operation. Subsequently, physical difficulties with the unit caused all previously retained arsenate to elute out of the unit in the next 2,000 BV. High sulfate concentrations in the influent make conventional ion exchange impractical in many cases. The IBR's process significantly extended the use of brine regenerant by replenishing the chloride concentration in the brine while simultaneously removing interfering sulfate anions from solution.