Biogas production by co-digestion of sodium hydroxide pretreated Napier grass and food waste for community sustainability

Abstract

ABSTRACT Community agricultural waste-to-energy management, especially in developing countries, can respond to sustainable development goals by the United Nations. Co-digestion techniques for waste from phytomass in fields as Napier grass (NP) and debris from consumption in the community as food waste (FW) into biogas production by conventional anaerobic digestion technology contribute to sustainable energy communities. However, lignocellulose requires proper pretreatment of the material type. Therefore, low sodium hydroxide (NaOH) concentration for Napier grass pretreatment and varying the co-digestion ratio with food waste from the community under conventional batch conditions were optimized to be economically cost-effective with elementary technology. The results showed the highest methane yield at 0.285 m3/kg VSadded at the 4% concentration of sodium hydroxide pretreatment with significant content of FW added with biomass. The best conditions of co-substrates can increase methane yields by up to 3.54 times compared to a single substrate. The energy and cost estimation based on energy consumption and chemical input cost showed that co-digestion with NaOH pretreatment could achieve the net benefits by increasing the biogas production (242 US$/tonne TS). This study confirms the application of waste management in agricultural communities that can be used as fuel in households to increase biogas and economic value. The authors expect this work to be a successful case study for further results that lack government financial support and limitations of advanced technology for a sustainable community.