Lab-scale and economic analysis of biogas production from swine manure

The current study presents a technical and economic evaluation of biogas production from swine manure in the Southern of Minas Gerais, Brazil. For the study, laboratory-scale experiments were performed by digesting the local samples in Anaerobic Sequencing Batch Reactors to evaluate the energy potential and economic feasibility for the entire enterprise in two scenarios. An environmental analysis, involving a matrix of environmental impact assessment and CO2 emissions avoided, was also performed. Scenario 1 resulted in Net Present Value greater than 0 for about 1,300 heads by including the sale of biofertilizer, while scenario 2 became economically viable from 10,468 heads, whose power was 14.69 kW. The economic viability of the system was ensured by the sale of organic fertilizer which accounted for approximately 72% of the revenue and highlighted the importance of its value in the implementation of the project. Most environmental impacts analyzed were positive, direct and permanent and CO2 emissions ranged from 2.81 to 27.10 tCO2eq/yr for 1,300–12,552 heads. Although the present study is applied to a specific enterprise, the methodology and the observed results can be applied in other national and international agricultural projects, contributing to the expansion of this technology.