Enhancing Biogas Production: Pre-Treatment of Lignocellulosic Biomass Using Biogas Plant Digestate

Pre-treatment of lignocellulosic biomass is a necessary step to improve the degradability of these materials when used as substrates for biogas production, due to their resistance resulting from their complex composition and structural properties. The effect of using digestate for the pre-treatment of maize waste to enhance biogas production in an anaerobic digestion process was assessed through biogas potential tests and long-term operation of an anaerobic reactor model. The biogas potential tests confirmed the positive effect of soaking maize waste in digestate for pre-treatment compared to soaking it in water, as higher specific biogas production rates of 17%, 18%, and 29% were achieved after soaking it in digestate for 1 day, 2 days, and 5 days, respectively. The results from monitoring the long-term operation of the anaerobic reactor demonstrated the suitability of using digestate-soaked maize waste as a co-substrate to maize silage, which may significantly reduce the dependence on maize silage in practical applications. Stable operation of the reactor was also achieved during anaerobic treatment of the pre-treated maize waste itself, with an average specific biogas production of 403 mL/g VS.