Climate Change Impact of Diverse Food Waste Valorization Processes beyond Anaerobic Digestion

For the beneficial utilization of food waste (FW), valorization processes that output high-value products including carbon source alternatives for biological nutrient removal, biochar, or refuse-derived fuels (RDF) are reported to be technically and economically beneficial, while the climate change impact of these emerging valorization technologies is unclear and lacks a benchmark for comparison. In this study, the climate change impacts of six diverse valorization scenarios for FW were evaluated through a life cycle assessment and compared with that of incineration and anaerobic digestion (AD). Six valorization scenarios all exhibit better climate change benefits than incineration (−40.8 kgCO₂-eq/t), and hydrolysis for the carbon source alternatives production coupled with thermal drying-RDF scenario and thermal drying-RDF scenario achieves the best (−276.8 kgCO₂-eq/t) and the second-best (−224.2 kgCO₂-eq/t) climate change benefits beyond AD with digestate incineration (−149.1 kgCO₂-eq/t). Sensitivity analysis implies that the diverse total solid content of FW, biodrying efficiency, hydrolysis efficiency, dewatering efficiency, and energy efficiency of biomass power plants are key parameters affecting the global warming potential results. This study provided the data basis and insight for estimating the climate change relating to FW valorization decision-making.