Produção de bioestruvita como estratégia de recuperação de fósforo a partir de águas residuárias

Abstract

The precipitation of struvite (MgNH4PO4•6H2O) is an environmental technology aimed at addressing the issues of eutrophication in water bodies. Furthermore, it enables the recovery of phosphorus and nitrogen to be used as fertilizer, potentially contributing to the demands of the agricultural sector. Its biological production is considered promising, as it proves to be more sustainable than physicochemical production. In this manner, the production of biostruvite by B. pumilus was assessed in synthetic media derived from two effluents: residual water from potato processing, post-anaerobic treatment, and hydrolyzed human urine. The assays were monitored over 0, 3, 5, 7, and 10 days, maintained at 30°C under agitation at 100 rpm. The crystals were characterized through scanning electron microscopy analysis, accompanied by energy-dispersive X ray spectroscopy and X ray diffraction. Incubation of synthetic urine yielded the highest microbial performance, resulting in the removal of 98% of acetate and 86% of phosphate, likely favored by the higher substrate concentration compared to the synthetic potato effluent. Crystals from both media exhibited quality characteristics compatible with their application as inorganic fertilizers. It was concluded that, based on the absence of precipitates in abiotic tests and pH values below 8.4 in the reactors, the struvite crystals are of biological nature.