Financial viability and carbon intensity of hydrothermal waste valorization systems for bio-based asphalt binder

This study evaluated the economic and environmental performance of converting food waste into bio-based asphalt binders and coproducts via hydrothermal liquefaction (HTL). Two deployment configurations were considered, including centralized HTL (c-HTL) and decentralized HTL (d-HTL) with upgrading processes to produce biobinders and biofuel additives. Five HTL aqueous phase (AP) management strategies were considered incorporating electrochemical (EC, EC H 2 , EC Future), disposal to centralized facilities (No EC), and fungal treatment. Techno-economic analysis (TEA) and life cycle assessment (LCA) showed that with an optimal feedstock, a highly cost-competitive biobinder could be produced with net negative emissions (<−$0.4/kg minimum selling price [MSP] with ~ − 6.3 kg CO 2 e/kg GWP 100 ) in the No EC scenario. These promising results were due to the diversion of food waste from landfills (credits from tipping fee and avoided emissions), the high biocrude yield, and simplified biocrude upgrading and HTL AP management processes. On the other hand, current EC-based systems had high MSPs (> $5.5 per kg) and GWPs (>0.9 kg CO 2 e/kg) due to the large capital and electricity requirements, whereas fossil-based binders report slightly lower GWP 100 emissions (0.64 kg CO 2 e/kg). Sensitivity analysis identified internal rate of return, electricity price, and electrode cost as key cost drivers, which was used in subsequent analyses, where the EC Future scenario demonstrated the potential to close economic and environmental performance gaps with expected technological and infrastructure improvements. Additional analyses on biocrude yield confirmed its significant impacts on system performance, and plant size analysis revealed that based on size >140 U.S. cities could support cost-competitive biobinder and biofuel production with high-yield food waste alone. • Valorizing food waste via HTL unlocks low-cost binders and fuels • Centralized vs decentralized HTL infrastructure compared • Current electrochemical processes raise MSP and emissions • Future EC improvement could close economic and environmental performance gaps • Mid-sized U.S. cities can support cost-competitive biobinder and biofuels production