Enhancing phosphorus bioavailability in sewage sludge through co-hydrothermal treatment with biomass

Effect of process parameters on phosphorus conversion pathways during hydrothermal treatment of sewage sludge: A review

“…The effect of HT temperature increase on the increase in P, Ca, Fe, Al, and Mg contents of solid products has been observed in many studies [7,47,50,58,67,76,79,90], and their results appear to confirm that temperature promotes P recovery in solid product via OP mineralization to orthophosphates followed by metal phosphate precipitation. Additionally, results from X-ray photoelectron spectroscopy (XPS) analysis also indicate that OP can hydrolyze into ortho-P/pyro-P during HT treatment [91,92], and that Fe 3+ ions from iron oxides and Al 3+ ions can combine with free orthophosphates to form FePO 4 and AlPO 4 [92].…”