Performance of mesophilic and thermophilic anaerobic digestion of food waste at varying organic loading rate: Methane production, pathogens reduction, and dominant microbial community dynamics

Anaerobic digestion (AD) is a promising technology for treating food waste by converting it into methane while mitigating environmental impacts. This study examined the impact of organic loading rate (OLR) on methane generation, pathogen reduction, and microbial community dynamics in thermophilic and mesophilic food waste AD. Results indicated that increasing the OLR from 2.5 to 5.5 g VS/(L center dot d) improved methane generation, with thermophilic reactor outperforming mesophilic one. However, an excessive OLR of 6.5 g VS/(L center dot d) inhibited the process. Pathogen removal efficiencies exhibited complex relationships with OLR, with higher removal rates for Escherichia coli at lower OLR and Salmonella at higher OLR. Additionally, thermophilic reactor exhibited advanced pathogen reduction compared to mesophilic reactor. Microbial community analysis revealed compositional variations linked to OLR changes, impacting both methane yield and pathogen levels. These findings offer insights for optimizing AD processes and provide valuable data support for safe treatment of food waste fermentation digestate.