title: Simultaneous recovery of phosphorus and potassium as magnesium potassium phosphate from synthetic sewage sludge effluent.
abstract: Bench-scale experiments were performed to investigate simultaneous recovery of phosphorus and potassium from synthetic sewage sludge effluent as crystals of magnesium potassium phosphate (MPP or struvite-(K), MgKPO4·6H2O). The optimal pH of MPP formation was 11.5. A phosphorus level of at least 3 mM and K:P molar ratio over 3 were necessary to form MPP, which showed higher content rate of phosphorus and potassium in precipitate. MPP crystallization was confirmed by analysing the precipitates using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) apparatus and an X-ray Diffractometer (XRD). Inhibition of MPP crystallization by iron and aluminium was confirmed by precipitation experiments and SEM-EDX analysis. Potassium ratio against magnesium in precipitate decreased for iron concentrations greater than over 0.2 mM and aluminium concentrations over 0.05 mM.
authors.affiliation: a Osaka City Institute of Public Health and Environmental Sciences , Osaka , Japan.
authors.forename: Satoshi
authors.identifier: http://orcid.org/0000-0002-5909-561X
authors.initials: S
authors.lastname: Nakao
authors.affiliation: a Osaka City Institute of Public Health and Environmental Sciences , Osaka , Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nishio
authors.affiliation: b Graduate School of Engineering, Osaka City University , Osaka , Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kanjo
mesh_terms: D011232:Chemical Precipitation; D008274:Magnesium; D017616:Magnesium Compounds; D010710:Phosphates; D010758:Phosphorus / Q000737:chemistry*; D011188:Potassium / Q000737:chemistry*; D017680:Potassium Compounds; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D017680:Potassium Compounds; D012722:Sewage; D010758:Phosphorus; C013216:potassium phosphate; D008274:Magnesium; D011188:Potassium
keywords: Sewage sludge effluent; exhaustible resource; phosphorus; potassium; struvite-(K)