Estudo da codigestão anaeróbia de dejetos bovinos e suínos: análise da viabilidade técnica e econômica

Abstract

The growth in bovine and swine productivity is the result of the modernization of intensive confinement production systems. However, the accumulation of waste, in the absence of sanitation, impacts the environment and favors the proliferation of diseases. The objective of the present work was to carry out a theoretical study of the energy utilization of biogas from the co-digestion of bovine and swine manure in anaerobic digesters, converting an environmental liability into a source of clean energy and production of digested organic matter, a natural biofertilizer. The mixture of two or more types of substrates aims to optimize the functionality of anaerobic digesters in the qualitative and quantitative aspects, providing continuous processes for the production of biogas. The analysis was made using theoretical data from the literature of daily production of manure per animal in which the best quantitative methane generation was the ratio of 4 parts of cattle manure to 1 part of pig manure. After analyzing the biogas production of the substrate, a technical and economic feasibility study was carried out using the investment projection tools Net Present Value (NPV), Internal Rate of Return (IRR) and Levelized Energy Cost (LCOE), as well as the mapping of the identified codigestion potential and the study of avoided emissions of Greenhouse Gases (GHG) associated with this application. The results showed that enterprises of biogas plants resulting from the co-management of manure become viable from 1,410 heads of cattle and 2,350 heads of pigs. This quantity of animals and proportion of waste results in a methane flow of 163,41 m³ ∙ d-1, which corresponds to an energy potential of 128 MWh ∙ year-1, classifying the project as distributed microgeneration according to the resolutions of the National Electric Energy Agency No. 482 / 2012 and No. 687/2015. The present study showed that biodigesters are important sanitation mechanisms for rural areas and ag