Tratamento de água cinza visando o desenvolvimento sustentável da agricultura familiar.

Abstract

Family farming has great economic and social importance linked to the supply of food for the domestic market, the generation of jobs, and exports. For the development of this activity, water is a determining resource. The reuse of gray water is a viable alternative for the production and sustainable development of family farming. This work aimed to evaluate the efficiency of physical, chemical and biological treatments of gray water generated in a public laundry in the municipality of Cabaceiras, PB, for use in irrigation, aiming at the sustainable development of family farming. The research was carried out with gray water from the public laundry of the rural community of Ribeira, located in the municipality of Cabaceiras, state of Paraíba.The physical treatment was carried out using a hydrocyclone. For the chemical and biological treatments, the concentrations of 1 g/L, 3 g/L and 5 g/L of the chemical coagulant aluminium sulfate and the biological coagulant of Moringa oleífera, respectively, were used in powder. Physical treatment resulted in a 30% reduction in turbidity and 44% in Chemical Oxygen Demand (COD). The chemical treatment with aluminium sulfate reduced 67% and 48% of the turbidity, respectively for the concentrations (1 g/L and 3 g/L) and the Electrical Conductivity (CE) increased by 32%. There was a small reduction of 12% in COD with a concentration of 5g / L and the pH was acid (4.5-3.8), not recommended for agricultural irrigation. The biological treatment with Moringa oleifera reduced 21% of EC with a concentration of 1g/L and 79% of turbidity with a concentration of 3g/L. Regarding COD, the concentration of 1g/L of Moringa oleifera decreased by 50%. The water treated by physical and biological processes fits the parameters for irrigation in family farming, and the most recommended concentration of Moringa oleifera was 1 g/L.