Environmental Assessment of Pig Manure Treatment Systems through Life Cycle Assessment: A Mini-Review

The primary aim of this research was to evaluate and compare the environmental impacts, throughout the life cycle, of the main treatment systems employed by the industry, as well as to identify the processes that contribute most to these environmental impacts. To achieve this, a bibliographical search was conducted using the Web of Science Core Collection database platform, utilizing the keywords "life cycle assessment", "pig", "treatment", and "manure" or "slurry". The search was restricted to publications from the last five years (2019-2023), resulting in a total of 66 publications that were then analyzed according to the functional unit (FU) adopted. For the 10 publications whose FUs were expressed in tons or cubic meters of treated manure, a descriptive and quantitative analysis was carried out. It was found that anaerobic digestion has been the most widely used treatment technology for pig manure over the past five years, according to the LCA methodology. These systems, configured as biogas and biofertilizer production facilities, have proven to be environmentally friendly and could play a crucial role in the energy transition and decarbonization of the energy matrix.