Carbon Footprint of Oil Extraction from Spent Coffee Grounds Using Ultrasound-Assisted Extraction

Spent coffee grounds, SCG, are a waste product generated in significant quantities due to the large and widespread consumption of coffee worldwide. Current waste treatment options are not the best, as they do not consider the potential of SCG as a raw material for a variety of high-value products, from a bio-refinery perspective, while contributing to a more circular economy. In a biorefinery, several processes must be considered that need to be optimized, not only from an economic point of view, but also from an environmental point of view, such as ultrasound-assisted solvent (hexane) extraction process of oil from SCG biomass, which is the focus of this work. Hence, in this work, the carbon footprint of this process is analyzed based on a Design of Experiments results and following the Life Cycle Assessment methodology from a "cradle-to-gate" perspective. The functional unit is 1 g of extracted oil. The IPCC methodology implemented in RECIPE is used and the calculations were performed in the Simapro V8.5.2 software. The results show that it is the ratio of liquid (solvent) to solid (SCG) that most influences the carbon footprint of the extraction process.