Operating Bicarbonate-Form versus Chloride-Form Ion Exchange Resins without Regeneration for Natural Organic Matter Removal

Abstract

Ion exchange (IX) is a promising drinking water treatment process for natural organic matter (NOM) removal. However, standard IX processes require frequent regenerations with concentrated NaCl solution, producing a brine that requires costly and complicated disposal methods. To alleviate the burden of IX brine, we previously proposed operating IX with infrequent regeneration to favor biomass development on the resins and thus benefit NOM removal through biomass contribution, a process referred to as biological ion exchange (BIEX). The objective of the present study is to evaluate the performance of BIEX filtration for NOM removal from primary IX to complete exhaustion using bicarbonate-form and chloride-form IX resins. Parallel pilot-scale bicarbonate-form and chlorideform BIEX were fed with surface water (dissolved organic carbon (DOC) = 7 mg C/L) for 9 months without regeneration. The results demonstrated that bicarbonate-form BIEX achieved a marginally lower DOC removal (median: 49% vs 53%), a higher biodegradable DOC (BDOC) removal (average: 50% vs 33%) and a similar disinfection byproduct precursor removal compared to chloride-form BIEX. Overall, BIEX filtration using bicarbonate-form and chloride-form IX resins offers a similar NOM removal efficiency and eases spent brine management.

Application of a carbon dioxide regenerated ion-exchange process for removing sulphate from drinking water: a simple approach to estimate process performance

“…Frequent regeneration with carbonic acid prevents any significant growth of a biological active biofilm comparable to BIEX – B iologically active I on EX change. 20,21 The strong discoloration of the anion exchanger material indicates partial DOC adsorption that cannot be reversed via carbonic acid regeneration. In Fig.…”

“…Frequent regeneration with carbonic acid prevents any significant growth of a biological active biofilm comparable to BIEX -Biologically active Ion EXchange. 20,21 The strong discoloration of the anion exchanger material indicates While the lab-scale plant was designed so that preferential flow was minimized, equal fluent distribution during the regeneration procedure could not be ensured. Although the lab-scale service cycles showed great replicability, the manual operation of the plant made it more error-prone than the automated pilot-scale plant.…”

Progress of Ultrafiltration-Based Technology in Ion Removal and Recovery: Enhanced Membranes and Integrated Processes

“…14,15 However, most ion exchange resins and adsorbents are not effective when treating wastewater with high concentration, and the regeneration of ion exchange resins and adsorbents is problematic. 16 Therefore, it is necessary to find more efficient and cleaner technologies for ion removal.…”

Revealing the effect of anion exchange resin conditioning on the pH and natural organic matter model compounds removal mechanisms

“…Researcher are looking for alternatives on the classical regeneration procedures to the Clform using brine to, with the aim to e.g. reduce brine generation or lower the risk of (pitting) corrosion caused by the released Cl-ions into the treated water [33][34][35][36]. The cationic and anionic resins applied in a water demineralization unit, are in the H + , resp.…”