(682f) Improving Food Waste Anaerobic Digestion Efficiency with Biochar in Decentralized System

Long-term anaerobic digestion of food waste encounters challenges like feedstock overloading, leading to volatile fatty acids accumulation and process disruption. Although biochar-enhanced anaerobic digestion shows promise in addressing these issues, its effectiveness in small-scale labs limits its adoption in decentralized anaerobic digestion systems. This study investigates the efficacy of biochar supplementation in such a decentralized setting, revealing that a modest biochar quantity (0.055 g/L) improves anaerobic digestion under ambient conditions (29°C). Within 36 days, volatile fatty acids inhibition decreases to a safe level of 1195 mg/L. The normalized specific biogas yield increases by 50% compared to the previous control study, reaching 1.40 ± 0.74 m³/kgVS. After achieving stability, anaerobic digestion at mesophilic conditions (35°C) without biochar sees a further 27.8% yield increase to 1.79 ± 0.83 m³/kgVS. Additionally, methane biogas concentration rises to 60-62%, compared to 56.9 ± 2.9% in the control study. In terms of microbiome composition, biochar enhances Methanosaeta genus methanogens by 30%, facilitating direct interspecies electron transfer and enhancing archaea-bacteria symbiosis. These findings highlight biochar's potential in decentralized biogas facilities and sustainable waste management, offering a replicable model for closing the food waste loop and advancing the bioeconomy.