Catalytic effect of the use of biochar particles in the treatments of high organic load waste through anaerobic digestion

This study investigates the catalytic effect of different particle additions on the anaerobic digestion (AD) of pig manure with a high organic load in a batch system. Over the course of 50 days, experiments were conducted to compare Fe3O4, Calpech, biochar, graphite, and Bio-Fe particles at two concentrations (5 and 15 mg/g VS) with a control essay. Kinetic characteristics were analyzed using the Gompertz model, which produced negative lag phases and strong regression coefficients (R2 >96%), indicating a good model fit and a rapid start to production for all samples. By Day 29, the control stopped producing biogas. Although Bio-Fe had the shortest lag phases and the highest biomethane production rate (up to 35.98 mL CH4 /g VS.d), its production ceased on Day 32. Biochar showed the highest cumulative biogas production (up to 667.4 mL/g VS) by maintaining activity for the entire 50 days. Additionally, Fe3O4 maintained production at higher rates. Interestingly, graphite produced significant inhibition at higher concentrations (R=16.31 mL CH4 /g VS.d). This study demonstrates the potential of Bio-Fe to speed up initial processes and emphasizes the improved long-term catalytic stability of biochar for anaerobic digestion treatment of waste with a high organic load.