Life cycle assessment of biomethane production by anaerobic digestion of soybean molasses: analysis of environmental impacts and comparison with current scenario

• Grant number: 24/06808-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: August 31, 2025
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Giovanna Lovato
• Grantee: Giovana Golin Nicolino
• Host Institution: Escola de Engenharia Mauá (EEM). Instituto Mauá de Tecnologia. São Caetano do Sul , SP, Brazil
• Associated research grant: 22/10615-1 - Consolidation of the biorefinery concept applied to the biological treatment of wastewater and solid wastes, AP.TEM

Abstract

The use of agro-industrial wastes for bioenergy production through anaerobic digestion has been highlighted by the growing push towards a circular economy. Soybean molasses, a by-product of soybean processing, emerges as a promising candidate in this process due to its low added value and high volume generated. Although there is a detailed description in the literature about the methane production process from this residue in anaerobic digestion reactors, currently, the most common destination for soybean molasses is its use in animal feed or direct burning in boilers. Therefore, the present study aims to evaluate the environmental impacts of three scenarios that dispose of soybean molasses: (i) direct burning of soybean molasses in boilers for energy production; (ii) use of soy molasses as animal feed; and (iii) use of soybean molasses as raw material for methane production through anaerobic digestion. To this end, a life cycle assessment (LCA) of the three scenarios will be carried out. This is an environmental management tool that assesses environmental impacts at each stage of a process. ISO 14040 describes the procedures followed. The study boundary is from gate to gate. This means the impacts will be evaluated from the entry of soybeans into the industrial plant to emissions into the air, soil and water after molasses processing. To carry out the project, GaBi® software will be used and the methodology for assessing life cycle impacts chosen was Recipe Midpoint. Based on the results of this study, it will be possible to conclude which scenario is the most environmentally favorable for the fate of soybean molasses.