TRATAMENTO DE EFLUENTES SUÍNOS POR WETLANDS CONSTRUÍDOS: AVALIAÇÃO DE PARÂMETROS FÍSICO-QUÍMICOS E ECOTOXICOLÓGICOS

Abstract

Pig farming is an intensive activity that generates large volumes of effluents rich in organic matter and nutrients, causing significant environmental impacts. This study evaluated the efficiency of constructed wetlands (CW) in treating swine effluents, using the macrophytes Junco (Juncus effusus) and Biri (Canna indica) at hydraulic retention times (HRTs) of 12, 24, 48, and 72 hours. The experiment was conducted on a pilot scale at the UNICENTRO campus in Irati, Paraná, Brazil, using three beds: two planted with macrophytes and one control without vegetation. The results showed that the planted beds performed better in pollutant removal, with the 24-hour HRT standing out as it balanced efficiency and operational feasibility. At this HRT, COD was reduced by 94% in the planted beds and 88% in the control bed, while ammoniacal nitrogen showed reductions of 78% and 57%, respectively. For total phosphorus, reductions of 80%, 64%, and 73% were achieved in the Biri bed, Junco bed, and control bed, respectively. Other parameters, such as turbidity, true color, and solids, also showed significant improvements, reinforcing the system's efficiency. Toxicological bioassays with Daphnia magna confirmed the reduction in toxicity in the treated effluent, with higher LC50 values observed in the planted beds. It is concluded that CWs are a viable and sustainable alternative for treating swine effluents, contributing to mitigating environmental impacts.