Evaluating Options for Regenerant Brine Reuse in Magnetic Ion Exchange Systems

The purpose of this work was to provide an empirical foundation for decisions regarding regenerant brine management in anion exchange systems for the removal of compounds that absorb ultraviolet (UV) light at a wavelength of 254 nm (UV₂₅₄) in drinking water treatment. Regenerant performance was assessed for fresh regenerant brine, reused regenerant brine, and used brine that had been treated with aluminum sulfate (alum) before reuse. Jar tests were conducted to examine the UV₂₅₄ reduction achieved by resins treated with each of these regenerants. Over three regeneration cycles, resin treated with continuously reused regenerant did not display a significant decline in UV₂₅₄ reduction. While treatment with alum was effective for removing UV₂₅₄-absorbing compounds from used regenerant brine, this treatment did not improve the brine's performance as a regenerant. These results demonstrate that regenerant brine may be reused several times without any intermediate treatment, which provides a cost-saving solution for treatment plants seeking to install anion exchange systems.