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 chloride-form 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.