AWWA WQTC64177

Pilot scale testing of fixed-bed anion exchange for removal of hydrogen sulfide was conducted over a one-year period to evaluate process performance and reliability at four well sites in west-central Florida. Exchangeable anions in the source waters included sulfide ( 1 to 3.2 mg/L), sulfate ( 1 to 50 mg/L), and total organic carbon (TOC) ( 1.5 to 7 mg/L). Supplemental testing was conducted to evaluate the impact of low levels of dissolved oxygen (< 2 mg/L) on the performance of the anion exchange system. Aerobic systems tended to support the growth of sulfur oxidizing bacteria near the top of the anion exchange columns. The byproducts of biological sulfur oxidation, sulfate and elemental (colloidal) sulfur, were removed through anion exchange. In general, the anion exchange systems were effective for removing hydrogen sulfide, sulfate, TOC, and reducing the chlorine demand and disinfection byproduct formation potential associated with each groundwater source. Regeneration of the resin with brine was effective at controlling biomass growth. The main benefit of coupling biological sulfur oxidation with anion exchange was an apparent increase in exchange capacity resulting in about two to three fold longer operating cycles, thus decreasing the frequency of regeneration. Includes 14 references, tables, figures.