Avaliação do tratamento de águas residuárias de suinocultura em biodigestores do tipo tubular e lagoa de estabilização e posterior uso como biofertilizante

Abstract

Swine farming is an activity that has expanded due to the increase in the demand for meats and their derivatives. However, this growth implies an increase in the amount of waste that presents polluting characteristics to the environment, especially when ha ndled incorrectly. Given the above, the objective of this work was to evaluate the treatment of swine residues in tubular model biodigesters followed by stabilization pond for later application as a biofertilizer in the corn crop. The wastewater was collected in the equalization tank (which precedes the treatment system), at the exit of the two biodigesters and in the stabilization pond. The following variables were analyzed: pH, total and thermotolerant coliforms, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total solids (ST), fixed solids (SF), volatile solids (SV), total nitrogen NTK), ammoniacal nitrogen (N-NH3) and total phosphorus (Ptotal). The treated effluent was applied to corn plants grown in pots under greenhouse conditions. The experiment consisted of five treatments with five replicates. Soil samples were collected in a dystrophic Red Latosol (LVd), at a depth of 0 to 20 cm, located at the Campus of UFLA. Subsamples were removed from several points in order to obtain a composite sample of soil for physical and chemical determinations. The accumulation of dry mass and the levels of macro and micro nutrients in corn shoot and in soil samples were analyzed. The results showed that the analyzed treatment system was efficient in reducing the organic load, in which a reduction of 80% of BOD and 79% of COD was observed. The application of wastewater from swine to the soil favors improved soil attributes and increased corn nutrition.