Name: NICHOLAS ALEXANDRE BERGER BENTO
Publication date: 14/12/2023
Examining board:
Name |
Role |
|---|---|
| PAULO SERGIO DA SILVA PORTO | Advisor |
Summary: This study investigated the nutritional potential of struvite (MgNH4PO4·6H2O), a fertilizer composed of magnesium, ammonium, and phosphate, obtained synthetically and from an industrial effluent. In addition to contributing to the recovery of water bodies by reducing concentrations of ammonium and phosphate, and preventing eutrophication, this precipitation technique results in a commercially valuable product due to the growing demand for fertilizers. The objective of the study was to evaluate the nutritional potential of struvite synthesized in an air-lift reactor in the cultivation of microalgae, based on determining the most efficient and economically viable struvite precipitation condition using synthetic effluent. Variations in molar ratios (without excess Mg; 25% and 50% excess Mg) and air agitation velocities (3, 4.5, and 6 L.min-1) in the fluidized bed, as well as reaction supersaturation based on ammonium concentration (125, 250, and 375 mg.mL-1), were analyzed. The evaluated responses included the removal of ammonium, phosphate, and magnesium, as well as struvite precipitation and the content of precipitate formation. He results indicate a 95% precipitate yield, highlighting the influence of ammonium concentration on the removals of Mg2+, NH4+, and PO43-. In Nannochloropsis oculata cultures, conducted with 'Guillard medium,' 'Guillard enriched with synthetic struvite,' 'Guillard enriched with industrial struvite,' and 'only struvite,' cultivation with only struvite demonstrated potential as a nutritional source, achieving a cell density of 2.57x107 cells.mL-1. The comparison between synthetically produced struvite and struvite from an industrial effluent revealed similar cellular growth behavior, suggesting equivalence in nutritional potential. It is concluded that, under the studied experimental conditions, the results are satisfactory, allowing to production of a fertilizer by the used air-lift reactor and effective application of struvite as a nutritional source in the cultivation of the microalga Nannochloropsis oculata.
