title: Recovering phosphorus as struvite from the digested swine wastewater with bittern as a magnesium source.
abstract: Recovering nitrogen and phosphorus through struvite (MgNH4PO4 6H2O) crystallization from swine wastewater has gained increasing interest. However, swine wastewater contains complex compositions, which may hinder the formation of struvite crystal and affect the purity of the precipitates by forming other insoluble minerals. In this work, experiments were carried out to evaluate struvite precipitation in the anaerobically digested swine wastewater, with dosing bittern as a low-cost magnesium source. Exceeded 90% phosphate removal and 23-29% ammonium reduction were obtained. FTIR, XRD and mass balance analysis were combined to analyze the species of precipitated minerals. Results showed that the precipitates were struvite, mixed with amorphous calcium phosphate (ACP) and brucite. The presence of Ca2+ diminished the percentage of struvite and gave rise to ACP formation. Controlling pH below 9.5 and bittern dosage above 1% (w/w) could inhibit ACP precipitation and harvest a highly pure struvite crystal product.
authors.affiliation: Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, Fujian 361021, China.
authors.forename: Zhi-Long
authors.initials: ZL
authors.lastname: Ye
authors.forename: Shao-Hua
authors.initials: SH
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Shi
authors.forename: Li-Feng
authors.initials: LF
authors.lastname: Lin
authors.forename: Shu-Mei
authors.initials: SM
authors.lastname: Wang
mesh_terms: D000818:Animals; D008274:Magnesium / Q000032:analysis*; D017616:Magnesium Compounds / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000302:isolation & purification*; D013055:Spectrophotometry, Infrared; D000069877:Struvite; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D008274:Magnesium