Phosphate Uptake by Precipitation in Model Animal Wastewaters: Adjusting Ionic Strength and Ionic Composition to Maximize Phosphorus Removal

While phosphorus is a limited resource that essential for agriculture, its release to the environment adversely impacts water quality. At same time, animal wastewaters contain significant quantities of and nitrogen can be recovered beneficial use. Phosphorus uptake experiments were performed with magnesium-treated corn-cob char magnesium silicate prepared using from rice straw at pH 8 9. The concentration dissolved as function total added ammonium chloride (NH4Cl) was determined, chemical equilibrium modeling used investigate trends mineral species. According modeling, carbonate alkalinity exerted demand, approximately half all forming magnesite (MgCO3(s)). As NH4Cl increased, excess Cl− complexed Mg2+ in competition orthophosphate, freeing orthophosphate precipitate, mainly struvite (NH4MgPO4·6H2O(s)). increased by factor ten, measured concentrations decreased meaning ionic composition has potential significantly impact amount