DESAFIOS NA OTIMIZAÇÃO DA DIGESTÃO ANAERÓBIA DE DEJETOS SUÍNOS EM BIORREATORES DE PEQUENA ESCALA

Abstract

The growing demand for renewable energy sources and the challenge of sustainable organic waste management make anaerobic digestion a promising alternative, especially in rural systems. This study aims to evaluate the efficiency of different types of anaerobic reactors in the production of biogas from swine manure, focusing on operational stability and the quality of the gas generated. Three types of laboratory bioreactors were used: glass with a stirrer, stationary glass, and PVC tubes, all subjected to controlled temperature conditions (37°C) and monitored over 120 days.

The analyses included weekly measurements of pH, FOS/TAC ratio, and gas composition (CH₄, CO₂, H₂S, O₂, and CO), using the Biogás 5000 equipment. The FOS/TAC ratio was adopted as a stability parameter, indicating the balance between volatile fatty acids and alkalinity of the system. The results showed that the agitated reactors presented greater stability, with FOS/TAC values ​​below 0.3 and consistent methane production, as well as low concentrations of undesirable gases such as H₂S and CO. However, the non-agitated and PVC reactors presented fluctuating indices, with peaks above 0.6. The agitated reactor was the most efficient and stable, favoring substrate homogenization and the activity of methanogenic microorganisms. The use of the FOS/TAC ratio as a monitoring tool proved essential for optimizing biogas production. The results obtained contribute to the improvement of biodigestion technologies in small-scale production, promoting sustainable practices and the reuse of organic waste.