Conversion and recovery process from glyphosate wastewater into phosphatic fertilizer on the continuous reaction system

Given the scarcity of phosphorus resources and the growing demand for phosphorus, it is imperative to recycle phosphorus from wastewater phosphorus-containing to ensure its sustainable use. The wastewater from the conventional wet oxidation process still contains a considerable quantity of glyphosate that has not undergone sufficient degradation. This poses a significant environmental risk due to the persistent presence of glyphosate. In this work, we achieved deep degradation of glyphosate effluent into phosphate (PO₄^3-) by PMS (Peroxymonosulfate, HSO₅⁻)/chlorine (Cl^-) system. Finally, phosphorus recovery was achieved by precipitation methods from the degraded effluent. In the conversion of glyphosate to inorganic phosphorus, the reactive chlorine produced by the PMS/Cl^- system is the main reactive species (degradation contribution rate of 70.67–85.5 %), and, to a lesser extent, singlet oxygen (¹O₂) is also an important oxidation pathway (degradation contribution rate of 14.5–29.33 %). Both batch reaction and continuous reaction systems successfully converted glyphosate into PO₄^3-, which was further transformed into phosphatic fertilizer by struvite or other Mg/Ca-P precipitation with > 90 % yield. The recovery of phosphate fertiliser from glyphosate wastewater is not only a technically feasible process, but also economically advantageous.