title: Use of a byproduct of magnesium oxide production to precipitate phosphorus and nitrogen as struvite from wastewater treatment liquors.
abstract: This paper describes a series of experiments designed to recover phosphorus and nitrogen from sewage in the form of struvite (MgNH(4)PO(4).6H(2)O), a potential fertilizer. Nitrogen and phosphate were recovered from a filtrate of digested sludge dewatered at the Arroyo del Soto Waste Water Treatment Plant (WWTP) (Madrid, Spain). A byproduct of the Spanish magnesite mining and MgO production industry was used as the magnesium source. The precipitating performance of this byproduct was compared to that of conventional chemical reagents such as pure MgO. The precipitates obtained were subjected to chemical, light microscopy, and X-ray diffraction analysis. The findings indicate the precipitate recovered using this byproduct contains several minerals with a predominance of struvite. Optimal purity ( approximately 80% struvite) was achieved using the sieved <0.04 mm grain size fraction of the byproduct at doses corresponding to a molar Mg:P ratio of 1.6.
authors.affiliation: Consejo Superior de Investigaciones Científicas, Centro de Ciencias Medioambientales, C/Serrano, 115-duplicado, 28006 Madrid, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Quintana
authors.forename: Manuel Fco
authors.initials: MF
authors.lastname: Colmenarejo
authors.forename: Jesús
authors.initials: J
authors.lastname: Barrera
authors.forename: Gema
authors.initials: G
authors.lastname: García
authors.forename: Elia
authors.initials: E
authors.lastname: García
authors.forename: Angel
authors.initials: A
authors.lastname: Bustos
mesh_terms: D011232:Chemical Precipitation; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry* / Q000302:isolation & purification; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry* / Q000302:isolation & purification; D012722:Sewage / Q000737:chemistry*; D000069877:Struvite
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D012722:Sewage; D010758:Phosphorus; D008277:Magnesium Oxide; D000069877:Struvite; D009584:Nitrogen