Life cycle assessment of swine manure management: A comparison of different management systems with Montecarlo simulation

Abstract

The agricultural industry deeply impacts in the environment due to methane, an important greenhouse gas (GHG), and ammonia emissions that causes acidification and eutrophication. Recognising the urgency of addressing the environmental impact, this study analyses different manure management strategies coupled with diverse energy sources. The principal analytical tool employed was Life Cycle Assessment (LCA), with a focus on evaluating environmental impacts and discerning the most sustainable approach within this context. In addition, Monte Carlo Analysis (MCA) was applied to explore how emissions may fluctuate in response to variations of manure composition. This research contributes to ongoing efforts to align agricultural practices with sustainability goals and reduce the environmental impact. Five scenarios proposed on the swine manure management, based on biogas and solar energy, demonstrate a substantial positive impact on the climate change category when an anaerobic digestion stage is incorporated into the process. Conversely, the impacts related with ammonia emissions were not significantly reduced with the introduction of renewable technologies in the farming. The MCA revealed a high dependence on the chemical composition of the manure for the impacts climate change and acidification in case of the simplest scenarios studied, without biogas production. The application of a solar energy system improves the energy balance and consequently reduce the overall environmental impact. In this sense, hybrid panels that simultaneously generate thermal and electric energy presented the highest energy recovery but significantly higher impacts on eutrophication, toxicity and resource use, due to the higher complexity of materials of these systems.