(176a) Techno-Economic Assessment of Food Waste to Biofuel By Integrated Hydrothermal Liquefaction with Microbial Electrolysis Cells

According to the United States Department of Agriculture (USDA), over 30% of the U.S. food supply is wasted or lost. A significant amount of this food waste ends up in landfills, contributing to greenhouse gas emissions and other environmental issues. Therefore, it is appealing to convert food waste into green energy in an environmentally friendly and efficient manner. Hydrothermal liquefaction (HTL) combined with microbial electrolysis cells (MEC) can effectively convert food waste into biocrude oil while treating the HTL aqueous phase to produce hydrogen for biocrude upgrading. In this study, a high-fidelity HTL/MEC process model was developed based on experimental data. A comparative techno-economic assessment (TEA) was then conducted to compare the performance of the HTL process with the traditional anaerobic digestion (AD) process for food waste at different plant scenarios. System-level analyses show that MEC can provide the necessary hydrogen for biocrude upgrading with 90% chemical oxygen demand (COD) removal efficiency. Additionally, the treatment cost of the HTL aqueous phase by MEC is comparable to the direct sewer discharge fee for high COD and NH3. The minimum fuel selling price (MFSP) for a 500 dry ton per day HTL/MEC process is $4.3/gasoline gallon equivalent (GGE). When compared to AD pathways in terms of levelized cost of disposal, the results show that AD pathways have a cost advantage at the community scale due to lower capital expenses. However, the integrated HTL/MEC process is cost-competitive with AD above 50 TPD scale.