Effect of Bamboo Biochar on Process Performance and Microbial Community Composition in Continuous Anaerobic Digestion of Liquid Dairy Biomass

The utilization of liquid dairy biomass (LDB) as an energy source has attracted growing attention, but its high organic content can hinder anaerobic digestion (AD) efficiency. This study investigated the effects of conductive materials on AD performance under high organic loading rates (OLR). After batch screening, granular activated carbon (GAC) and bamboo biochar (BBC) were introduced into continuous stirred tank reactors. At an OLR of 4.80 kg-COD/m3/d, BBC showed the highest methane yield (0.141 m3/kg-COD), outperforming GAC and the control. Microbial analysis revealed that BBC enriched Methanomassiliicoccaceae and altered hydrogen utilization pathways, indicating a shift in methanogenic metabolism. These results suggest that conductive materials, particularly BBC, significantly enhance the efficiency and stability of AD for LDB treatment, making them promising additives to improve LDB processing.