title: Optimization of struvite precipitation in synthetic biologically treated swine wastewater--determination of the optimal process parameters.
abstract: A sustainable way to recover phosphorus (P) in swine wastewater involves a preliminary step of P dissolution followed by the separation of particulate organic matter. The next two steps are firstly the precipitation of struvite crystals done by adding a crystallization reagent (magnesia) and secondly the filtration of the crystals. A design of experiments with five process parameters was set up to optimize the size of the struvite crystals in a synthetic swine wastewater. More than 90% of P was recovered as large crystals of struvite in optimal conditions which were: low Mg:Ca ratio (2.25:1), the leading parameter, high N:P ratio (3:1), moderate stirring rate (between 45 and 90 rpm) and low temperature (below 20 °C).These results were obtained despite the presence of a large amount of calcium and using a cheap reactant (MgO). The composition of the precipitates was identified by Raman analysis and solid dissolution. Results showed that amorphous calcium phosphate (ACP) co-precipitated with struvite and that carbonates were incorporated with solid fractions.
authors.affiliation: IRSTEA/Cemagref, 17 avenue de Cucillé, CS 64427, 35044 Rennes Cedex, France. aurelie.capdevielle@irstea.fr
authors.forename: Aurélie
authors.initials: A
authors.lastname: Capdevielle
authors.forename: Eva
authors.initials: E
authors.lastname: Sýkorová
authors.forename: Béatrice
authors.initials: B
authors.lastname: Biscans
authors.forename: Fabrice
authors.initials: F
authors.lastname: Béline
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Daumer
mesh_terms: D000641:Ammonia / Q000737:chemistry; D000818:Animals; D002118:Calcium / Q000737:chemistry; D011232:Chemical Precipitation; D003460:Crystallization; D005308:Fertilizers; D008274:Magnesium / Q000737:chemistry; D017616:Magnesium Compounds / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry; D059027:Recycling / Q000379:methods*; D000069877:Struvite; D013552:Swine; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*
chemical_list: D000641:Ammonia; D002118:Calcium; D005308:Fertilizers; D008274:Magnesium; D017616:Magnesium Compounds; D009584:Nitrogen; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D062065:Wastewater