Laboratory and pilot-scale phosphate and ammonium removal by controlled struvite precipitation following coagulation and flocculation of swine wastewater
ABSTRACT To reduce the suspended solids load to a trickling filter installation, raw swine effluent was pre-treated with ferric chloride and a cationically charged polyacrylamide coagulant resulting in unexpected struvite accumulation downstream of this post-separation process. Using this pre-treated swine manure, struvite precipitation studies were carried out as a function of pH at laboratory and pilot batch and continuously operated scales. An optimal reaction time of 30 min was established for struvite precipitation in the pre-treated swine wastewater at pH 8.5, minimizing the co-precipitation of interfering minerals. Ferric chloride addition resulted in magnesium solubilization, such that no external additional source of magnesium was required for struvite formation. Aeration alone did not result in significant pH increases, so base addition was required for pH adjustment. X-ray diffraction revealed that the only crystalline phase produced was struvite. Removal of phosphate and ammonium attained 98% and 17% respectively in laboratory scale experiments. At the pilot-scale, removal attained 99% and 15% of phosphate and ammonium in both batch and continuously HRT = 1h) operated reactors.
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ABSTRACT: Swine wastewater containing high concentration of phosphorus (P) and nitrogen (N) was treated by struvite precipitation method. The pH showed to have strong influence on N and P removal, whereas the excess of ammonia in the reaction medium did not show influence. The precipitated crystals were identified and analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and surface area (BET) revealing that there was the formation of a pure and crystalline phase mesostructured at pH 9.5 with an average crystal size in nanometric scale.Desalination and water treatment 03/2013; 51(13-15):2776-2780. DOI:10.1080/19443994.2012.749378 · 0.99 Impact Factor
Environmental Engineering Science 04/2014; 31(4):167-175. DOI:10.1089/ees.2013.0313 · 0.93 Impact Factor
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ABSTRACT: To address the issues of wastewater treatment and depleting phosphorus (P) resources, the present review focuses on the very wide interest in P recovery from wastewater, with scientific research underway in countries across the globe. The study describes the growing concern for diminishing P resources and then the chemical principle of magnesium ammonium phosphate (MAP) precipitation, factors influencing MAP crystallization, and various developments achieved through bench, pilot and full scale MAP reactors. A brief description is given of MAP purification and dissolution to economically exploit MAP as a phosphate and magnesium source. Experience in re-use of recovered MAP as a sustainable agriculture fertilizer is discussed including pot and field trials. © 2012 Society of Chemical IndustryJournal of Chemical Technology & Biotechnology 02/2013; 88(2). DOI:10.1002/jctb.3936 · 2.49 Impact Factor