Intensified Enrichment and Leaching Strategy of Phosphorus in Sewage Sludge via Species-Targeted Conversion

Le résumé fourni par la source

Wet-chemical method for extracting phosphorus (P) from sludge incineration ash suffers from great P loss in the incineration and P-leaching stages due to the multidirectional migration of diversified P species. Existing single-process optimizations are difficult to meet the diverse and often conflicting needs of the two upstream and downstream processes to recover different P species. Herein, we developed a system-oriented strategy, HyperPhos Ⓟ, to synergistically address multiprocess requirements. It employs a specially designed one-pot pretreatment to create a unique reaction window for the most recoverable Fe/Al–P, achieving the targeted transformation of unstable P species into homogeneous Fe/Al-orthophosphate of 85.6% in proportion. These compounds exhibited remarkable thermal stability during incineration, with volatilization loss of only 60% of conventional technical route (Conv-Tech) even at 1000 °C. Subsequently, these parts of P were completely leached out using H 2 C 2 O 4 or NaOH through redox reaction and chelating displacement, with the solvent concentration and the codissolution amounts of heavy metals less than half of the mean levels in the literature. Techno-economic analysis showed that HyperPhos Ⓟ obtained 1.1–2.4 times more P than Conv-Tech, while the unit cost was reduced by up to 49.5%. These findings provide new opportunities to close the P-cycle in a sustainable, economical, and environmentally friendly approach.

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