Chemically Enhanced Primary Treatment of Municipal Wastewater with Ferrate(VI).

Chemically enhanced primary treatment (CEPT) with ferrate(VI), a multifunctional treatment agent, was investigated for treatment of municipal wastewater in a laboratory-scale study. The treatment performance was evaluated at different ferrate(VI) doses (0.0-9.0 mg/L) and pH (6.0 and 7.5). The optimal removals of total suspended solids (TSS) (52%), total chemical oxygen demand (COD) (34%), and total phosphorus (47%) were achieved at the highest ferrate(VI) dose (9.0 mg/L) and the weakly alkaline condition (pH 7.5). The pollutant abatements principally ascribed to formation of large-sized aggregate and ensuing sedimentation fell within the reported ranges of CEPT with traditional coagulants. However, different from conventional CEPT, ferrate(VI) appreciably removed recalcitrant dissolved organic phosphorus (49%) and simultaneously inactivated total coliform (3.30 log removal) and E. coli (3.67 log removal) at 9.0 mg/L Fe(VI) and pH 7.5. The CEPT with ferrate(VI) offers an innovative alternative for improving municipal wastewater treatment.