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

Abstract: 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.