Abstract
Among the different alternatives for the production of biofuels, food waste could be a favorable bioenergy source. Using food waste as a feedstock has the potential to meet the expectations of the second generation of biofuels, in terms of environmental savings and revenue-generation, and which, along with other valuable co-products, can contribute to biorefinery profits. This study aimed to investigate the early stages of life-cycle assessment (LCA) for restaurant food waste processed into bioethanol, biomethane, and oil, split over different scenarios. Based on a life cycle inventory analysis, the environmental impacts were assessed using an IMPACT 2002+ methodology. The characterized impacts were then normalized against the average impacts, and the normalized results were weighted and aggregated to provide single score LCA results. The overall findings showed that electricity consumption and condensates included VFAs, as well as enzymes, yeast, and n-hexane, were the main contributors to the environmental burdens in all impact categories. Considering the sensitivity analysis, the results demonstrated that the enzyme dosage loading in the hydrolysis process and n-hexane utilization in the fat extraction process can change the environmental performance, along with the process efficiency. This study can provide an approach to foresee environmental hotspots in the very early developmental stages of food waste valorization into biofuels, and for highlighting drawbacks connected to the implementation of conversion processes at pilot and industrial scales.