Start-up of non-bioaugmented pumice biofilters in flow-through and recirculating flow regime for Mn removal

Abstract Biofilters are effectively used for drinking water treatment. However, the long ripening time of virgin media manganese (Mn) removal is a major concern. In this study, influence flow regime on pumice medium was investigated. For purpose, pilot-scale experiments were performed to compare start-up flow-through and recirculating filter columns using inherent inoculation with same groundwater source. The systems operated at 2 m·h−1 gradual increments up 5 avoiding Fe-loading. Effective Mn (>90%) in achieved after 8 23 days, respectively. Flow-through reached compliance local criterion (Mn < 0.1 mg·L−1) 15 cm depth 11 days. Recirculating required 32 days reach 30 depth. recirculation resulted consumption reduction about 50% compared regime. intermittent provision Mn-loading impacted Mn-oxidizing bacteria (MOB) concentration stone medium. Both regimes similar total (0.16 0.11 kg·Mn·m−2, respectively), suggesting that limiting factor pumice.