Precipitação de estruvita em lixiviado de compostagem para uso como fertilizante.

Nutrient recovery from agro-industrial effluents as precipitate minerals for use as fertilizers in agriculture is a promising strategy to reach sustainability. Struvite precipitation (MgNH4PO4.6H2O) is one of the most studied methods for phosphorus (P) recovery from waste waters; its use as a slow-release fertilizer has been often tested. This method also allowed the potassium (K) recovery as K-struvite (MgKPO4 .6H2O). The leachate has been considered as a major threat of composting facilities to the environment - due to its high biochemical oxygen demand and nutrient content (K, N e P). The leachate from a composting of horse bedding manure and left vegetables from an agro-processing industry showed high content of K (2,256 mg L -1), and low levels of ammoniacal nitrogen (217 mg L-1) and P (83 mg L-1). Adding soluble sources of phosphorus (H 3PO4) and magnesium (MgCl2) followed by pH adjusting (8 to 10), we reached the simultaneous formation of NH 4-struvite and K-struvite, as evidenced by X-ray diffraction. Besides composting leachate, struvite precipitation might be a feasible route to other agro-industrial waste waters with high K and N. Este estudo objetivou avaliar a composição de nutrientes do lixiviado da compostagem de esterco de cavalo e sobras de hortaliças de uma agroindústria de processamento mínimo e o potencial para a recuperação de nitrogênio amoniacal (NH 4+) e potássio (K) na forma de estruvita em condições de laboratório.