Quail manure as a supplementary feedstock to corn stover: Conjoint effect of alkaline pretreatment and co-digestion approaches on organics solubilization and methane yield

Abstract

To overcome low carbon/nitrogen (C/N) ratio, recalcitrant nature, and enhancement methane production of corn stover, it was co-digested with quail manure along with alkaline pretreatment using NaOH. The best-case scenario was attained when a mixture of 50/50 with 2.5% NaOH pretreated corn stover was employed. As compared to control (mono-digested/untreated corn stover), largest lignin reduction (16%), organics solubiliztion (27.7%), maximum methane yield enhancement (2-fold higher, 296.5 mL CH4 gVSadd−1) was achieved. The most important contributing factor to enhancement was the synergistic effect resulting from ideal C/N ratio applied and hydrolysis rate accelerating. The experimental data obtained were validated using first-order kinetic model. Energy analysis revealed a positive energy balance, with a 6-fold increase in energy output. These results highlight the feasibility of recycling available agricultural wastes into renewable resources rather than just discarding them, with the added benefits of producing clean biogas without the need for expensive high-tech equipment.