Enhancing Biomethane Production from Food Waste Hydrothermal Carbonization Liquid Through Catalyst Addition and Process Optimization

This study investigated the influence of hydrothermal carbonization (HTC) conditions and TiO2/biochar catalyst addition on the biochemical methane potential (BMP) from food waste (FW) hydrothermal carbonization liquid (HL) during anaerobic digestion (AD). Employing central composite design-response surface methodology, HTC conditions were optimized to produce different HL variants, and the impact of TiO2/biochar addition to the HTC system for HL BMP was examined. Variant 3 (T240, RT150, W200, C2) with the highest catalyst addition demonstrated the highest BMP (274.03 mL/gVS), while variant 5 (T240, RT150, W200, C0) without catalyst addition showed the lowest BMP (40.09 mL). The value of variant 5 was lower than the control suggesting inhibition of the AD process. The obtained results suggest that using TiO2/biochar catalyst during HTC is crucial for using HL for methane fermentation and biomethane production. The presented findings show a feasible approach for boosting BMP and the dual utilization of food waste.