Phosphorus fractionation and protein content control chemical phosphorus removal from corn biorefinery streams

Samuel Aguiar, Linhan Yang, Manying Zhang, Navneet Sharma, Vijay Singh, Roland D. Cusick

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Pages (from-to)220-227
Number of pages8
JournalJournal of Environmental Quality
Volume49
Issue number1
DOIs
StatePublished - Jan 1 2020

ASJC Scopus subject areas

  • Environmental Engineering
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Management, Monitoring, Policy and Law

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