Avaliação do ciclo de vida das etapas de construção e operação de sistemas de manejo de dejetos suínos

Abstract

The intensified swine production in Brazil brings the need to evaluate, develop and apply alternative management technologies that minimize negative impacts to the environment. Thus, the main objective of this study was to compare the environmental aspects and potential impacts of the construction and operation phase of three manure management systems (aerobic composting, anaerobic biodigesting and anaerobic pig slurry storage) from the swine industry using the methodology of Life Cycle Assessment (LCA). The LCA was performed through individual analysis and system comparison, using Simapro 8.2.3 software and the ReCipe method. The boundaries of the system included the collection of waste in the dwelling until its transformation into final product as fertilizer, and the functional unit was 1m³ of treated waste. Hence, in the individual analysis of the systems, the results showed that the most striking impact categories in the construction phase are marine ecotoxicity (ECM) and freshwater ecotoxicity (EAD) for the composting and biodigesting, and for the manure are the fossil depletion (DF) and ECM. In the composting and biodigesting systems the material with the greatest impact was steel, representing 98.73% and 98.73%, and 99.63% and 99.62%, respectively in each category. The high density polyethylene (HDPE) represented 89.28% in the DF category and 69.09% in the ECM category. When comparing these systems, both in terms of impact categories and in terms of damage categories, the results were equivalent, where the construction of the pig slurry storage presented the best environmental performance, followed by biodigesting and composting. In the phase of operation, the analysis of the Climate Change (CC) category showed that the "Compounds C, B and E" (elements related to gaseous emissions) were responsible for the major of impacts, representing 53.95%, 48.28% and 100 %, respectively. Finally, when comparing the operation phases (categories of impacts and damages), biodigesting for energy purposes was found with the best environmental performance, followed by the pig slurry storage, non-energetic biodigesting and composting.