Pilot‐Scale Evaluation of Bicarbonate‐Form Anion Exchange for DOC Removal in Small Systems

Abstract

This article highlights results from an ion exchange (IX) pilot‐plant study that evaluated bicarbonate‐form anion exchange resin (AER) with sodium bicarbonate (NaHCO3) regeneration for dissolved organic carbon (DOC) removal. Sodium chloride (NaCl) is the conventional regeneration salt; however, NaHCO3 could be used as an alternative to reduce the environmental impacts associated with NaCl brine disposal. In a comparison of chloride‐form AER and bicarbonate‐form AER, results indicated that chloride‐form AER and bicarbonate‐form AER have a similar affinity for DOC; chloride‐form AER treats more bed volumes before breakthrough than bicarbonate‐form AER; chloride‐form AER is regenerated 10–48% more efficiently with NaCl compared with bicarbonate‐form AER regenerated with NaHCO3; polyacrylic AER is regenerated more efficiently than polystyrene AER using both NaCl and NaHCO3; and the total cost of using NaCl and NaHCO3 is comparable when brine disposal is considered. Results from this study provide guidance for small water systems considering IX treatment.