title: Recovery of struvite from animal wastewater and its nutrient leaching loss in soil.
abstract: Contaminants in swine wastewater were recovered in the form of struvite, a crystal of magnesium ammonium phosphate (MAP), using a newly designed process, and the leaching loss of MAP in soil was examined. The continuous flow process was operated under optimal conditions: 1.0 molar ratio of magnesium (Mg) addition with respect to orthophosphate (OP) and an aeration rate of 0.73 L/L min. Five treatments were performed with three replications for soil pH and nutrient leaching loss tests. It was found that 93% of the OP in the swine wastewater was crystallized, and the MAP crystal formation was verified by X-ray diffraction (XRD) and scanning electron microscope (SEM) analyses. The analyses revealed that the pattern of pH change and N leaching losses for MAP-treated soil were remarkably different from those for fused super phosphate (FSP)-urea-treated soils. The pH levels for the control and FSP-urea-treated soils after a five-week experiment were unchanged or slightly decreased, whereas an increase in pH was observed in the MAP-treated soils. Leaching loss of N was higher in FSP-urea treatments, with MAP treatments showing N losses of only 1.93 and 2.05%, respectively, while FSP-urea treatments showed N losses of 7.82 and 6.47%, respectively, during the same period. Phosphate (P) leaching was very slow in both MAP- and FSP-treated groups.
authors.affiliation: Laboratory of Livestock Environment, College of Animal Life Science, Kangwon National University, Chunchon 200-701, South Korea.
authors.forename: Md M
authors.initials: MM
authors.lastname: Rahman
authors.forename: YingHao
authors.initials: Y
authors.lastname: Liu
authors.forename: Jung-Hoon
authors.initials: JH
authors.lastname: Kwag
authors.forename: ChangSix
authors.initials: C
authors.lastname: Ra
mesh_terms: D000383:Agriculture; D000818:Animals; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000032:analysis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000032:analysis; D010710:Phosphates / Q000032:analysis* / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis*; D012995:Solubility; D000069877:Struvite; D013552:Swine; D014865:Waste Disposal, Fluid / Q000379:methods*; D014961:X-Ray Diffraction
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D012989:Soil Pollutants; D010758:Phosphorus; D000069877:Struvite; D009584:Nitrogen