Ferrate(VI)\nTransformation of Nitrogen in Secondary\nWastewater Effluent: Implications for Water and Nutrient Management

Ferrate(VI) is a promising chemical agent for wastewater\ntreatment.\nWhile targeting various contaminants, it can inevitably react with\ndifferent water matrix constituents such as nitrogen (N) species.\nHowever, the reactions of ferrate(VI) with wastewater N compounds\nremain poorly understood. This study explores ferrate(VI)-mediated\ntransformations of different N species in a secondary wastewater effluent.\nFerrate(VI) oxidation minimally abated total dissolved nitrogen (TDN),\nwhile oxidizing dissolved organic nitrogen (DON) into dissolved inorganic\nnitrogen (DIN), primarily nitrate nitrogen (NO<sub>3</sub><sup>–</sup>–N), without noticeably altering ammonia nitrogen (NH<sub>3</sub>–N) levels. Consequently, ferrate(VI) treatment increased\nthe fraction of bioavailable, soil-leachable NO<sub>3</sub><sup>–</sup>–N while lowering the portion of less bioaccessible DON. This\nstudy reveals the ability of ferrate(VI) to retain overall nitrogen,\nimprove its bioavailability, mitigate the precursors of harmful nitrogenous\ndisinfection byproducts, and enhance nitrogen leachability in soil.\nThese insights highlight the complex impacts of ferrate(VI)-enabled\nwastewater treatment on human and environmental health, water supply,\nand nutrient management in agriculture reuse.