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Abstract Background and objectivesWet milling (WM) plants contribute to both point source and nonpoint source phosphorus (P) pollution by concentrating P in the coproduct corn gluten feed (CGF), the majority of which is undigested when consumed by ruminants, leading to manure management concerns. Phosphorus runoff from the manure consequently causes eutrophication in the water bodies downstream. This study investigates the economic feasibility of recovering the phosphorus at the front end from light steepwater to reduce P in CGF. FindingsThe amount of phosphorus in CGF was observed to reduce from 11.94 mg/g (db) to 2.44 mg/g (db), with phosphorus removal in the recovery unit calibrated with laboratory experiments. Direct fixed capital cost of $6.9 MM was estimated for the phosphorus recovery unit in an existing WM plant. ConclusionsWith a phosphorus recovery rate of 0.17 MT/hr, the operating cost of P recovery at the front end was estimated to be $1.23/kg‐P removed. Significance and noveltyRamifications of excess phosphorus in CGF on environment are an important understudied area. This study provided economic and technical feasibility of phosphorus recovery from CGF in WM industry, consequently producing a new coproduct and reducing the environmental burden. 

Abstract The economic viability of corn biorefineries depends heavily on the sale of coproducts as animal feeds, but elevated phosphorus (P) contents can exacerbate manure management issues. Phosphorus removal from light steep water and thin stillage, two concentrated in‐process aqueous streams at wet milling and dry‐grind corn biorefineries, could simultaneously generate concentrated fertilizer and low‐P animal feeds, but little is known regarding how differences in stream composition affect removal. To address this data gap, we show that the solubility of P in light steep filtrate (LSF) and thin stillage filtrate (TSF) exhibits distinct sensitivity to calcium (Ca) and base addition due to differences in P fractionation and protein abundance. In LSF, P was primarily organic, and near‐complete removal of P (96%) was observed at pH 8 and a Ca/total P (TP) ratio of 2. In TSF, TP removal was lower (81%), and there was more equal distribution of organic and orthophosphate, indicating that the Ca requirements of inorganic P precipitation were a limiting factor. The C/H/N ratio, elemental characterization, and crude protein analysis of the precipitated solids indicated that coprecipitation of amorphous solids containing Ca, Mg, and K with soluble proteins facilitated removal of P, particularly in LSF. Although the removal mechanisms and solubility limits differed, these results highlighted the magnitude (40–70 mM) and efficacy (80–96%) of P recovery from two biorefinery streams.