title: Recovery of phosphorus as struvite from sewage sludge ash.
abstract: Phosphorus (P) is an element vital for all living organisms, yet the world's reserves of phosphate rock are becoming depleted. This study investigated an effective P recovery method from sludge ash via struvite precipitation. Results showed that more than 95% of the total P content was extracted from sludge ash by applying 0.5 mol/L HCl at a liquid/solid ratio of 50 mL/g. Although heavy metal leaching also occurred during P extraction, cation exchange resin efficiently removed the heavy metals from the P-rich solution. Orthogonal tests showed that the optimal parameters for P precipitation as struvite would be a Mg:N:P molar ratio of 1.6:1.6:1 at pH 10.0. X-ray diffraction analysis validated the formation of struvite. Further investigations revealed that the harvested precipitate had a high struvite content (97%), high P bioavailability (94%), and low heavy metal content, which could be considered a high quality fertilizer.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Huacheng
authors.initials: H
authors.lastname: Xu
authors.forename: Pinjing
authors.initials: P
authors.lastname: He
authors.forename: Weimei
authors.initials: W
authors.lastname: Gu
authors.forename: Guanzhao
authors.initials: G
authors.lastname: Wang
authors.forename: Liming
authors.initials: L
authors.lastname: Shao
mesh_terms: D011232:Chemical Precipitation; D017745:Incineration; D017616:Magnesium Compounds / Q000302:isolation & purification*; D010710:Phosphates / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry* / Q000302:isolation & purification; D012722:Sewage / Q000737:chemistry*; D000069877:Struvite
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D012722:Sewage; D010758:Phosphorus; D000069877:Struvite