Análise do potencial bioquímico do metano em sistemas de mono e co-digestão a partir da vinhaça e resíduos da pecuária

Abstract

Finding renewable energy sources linked to more sustainable waste treatment practices can bring benefits to both the environmental and energy sectors. Vinasse, resulting from ethanol and sugar production, stands as one of the main effluents in the system and requires proper treatment. Similarly, livestock waste causes environmental impacts and should undergo treatment before final disposal. From this perspective, anaerobic digestion emerges as an effective alternative for treating these wastes, especially due to its ability to generate by-products that can be utilized for energy, such as biogas. This study examines the integration of the sugarcane and livestock sectors through mono-and co-digestion of vinasse and bovine manure. Characterization was conducted through physical-chemical analysis of solid content (SVT), pH, and alkalinity of eight different conditions regarding the variation in the proportion of vinasse and manure in the digestion tests. These conditions included positive control, negative control, 100% vinasse, 100% manure, 80% vinasse with 20% manure, 90% vinasse with 10% manure, 95% vinasse with 5% manure, and 98% vinasse with 2% manure. The assays lasted 165 days, and at the end of the experiment, an evaluation of the biochemical methane potential was conducted, reaching 65% in all experiments. The modified Gompertz model was identified as a suitable fit for most experimental results. The proportion of 90% vinasse and 10% manure showed the highest BMP value (1095.1 ml CH4/g SVT), suggesting potential for practical application during a possible sugarcane offseason. However, it was emphasized to consider the specific characteristics of the residues and local conditions to effectively optimize the co-digestion process in different scenarios.