title: Precipitation of liquid swine manure phosphates using magnesium smelting by-products.
abstract: Swine manure contains considerable amounts of total (P) and soluble phosphorus (PO(4)-P) which may increase the soil P content when applied in excess to crop requirements and, consequently, risk water eutrophication. The feasibility of using magnesium (Mg) from the by-product of electrolysis and foundries (BPEF) for the removal of P from liquid swine manure was studied by adding up to 3 g of Mg as BPEF per liter of nursery (NU) and grower-finisher (GF) swine manure in 25-L plastic buckets. Changes in P and other elements were monitored for up to 360 h. Small amounts of Mg as BPEF (0.5 and 1.0 g Mg L(-1) manure) reduced the total P concentration of the liquid fraction by 70 to 95% of both manure types with respect to the control treatment of mixed raw manure. A settling period of 8 h or more was necessary to significantly reduce the liquid fraction's total P concentration for both manure types. Reduction of PO(4)-P varied from 96 to 100% in the liquid fractions for both manure types, which along with natural settling, explains most of the total P reduction in that fraction. The addition of BPEF did not influence the N content of manure. The low P liquid fraction can be safely applied to saturated P soils whereas the high P solid fraction offers the opportunity of transporting manure to agricultural soils deficient in P. Since N is conserved, both liquid and solid fractions could be valuable fertilizer manure by-products.
authors.affiliation: Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd., Quebec, QC, Canada G1V 2J3. parentg@agr.gc.ca
authors.forename: Gaétan
authors.initials: G
authors.lastname: Parent
authors.forename: Gilles
authors.initials: G
authors.lastname: Bélanger
authors.forename: Noura
authors.initials: N
authors.lastname: Ziadi
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Deland
authors.forename: Jean
authors.initials: J
authors.lastname: Laperrière
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D011232:Chemical Precipitation; D004572:Electrolysis; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008274:Magnesium / Q000032:analysis / Q000737:chemistry*; D008372:Manure / Q000032:analysis*; D008669:Metallurgy; D009584:Nitrogen / Q000032:analysis; D010710:Phosphates / Q000032:analysis / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D013552:Swine
chemical_list: D007220:Industrial Waste; D008372:Manure; D010710:Phosphates; D010758:Phosphorus; D008274:Magnesium; D009584:Nitrogen; D002118:Calcium