Biogas Generation and Nutrient Recycling from Sugarcane Distillery Residues through Anaerobic Digestion

Press mud and raw spent wash or vinasse, are the two main high strength organic wastes from the sugarcane sector that anaerobic digestion is known to be an efficient and sustainable method of treating. Due to their significant organic loading and improper disposal techniques, these by-products are handled independently and pose a major environmental risk. In order to evaluate current trends in biogas generation and nutrient recovery, the origin, properties, and biomethane potential of both press mud and raw spent wash were investigated in this study. Methane generation has been observed to range from around 0.24 L/g volatile solids in the case of press mud to 0.45–0.55 Nm³ per kilogram of COD removed for spent wash, despite a satisfactory removal efficiency of COD ranging from 65% to 85%. Depending on the mixing ratio, co-digestion of these wastes boosts methane generation by 12–59%, improves biodegradability, optimizes the carbon–nitrogen balance, and lessens inhibitory effects. In order to assist and strengthen circular economy activities, this article also evaluated how anaerobic digestion fits into the operations of a sugarcane distillery. Reusing press mud and Biomethanated Spent Wash (BMSW) as organic fertilizers greatly increases crop output while lowering the quantity of chemical fertilizers used. While yields increased by about 5% for BMSW and 15% for press mud, field observations showed a decrease in the amount of DAP and urea utilized. In summary, the results have demonstrated that anaerobic digestion combined with agricultural reuse creates a regenerative cycle that increases the economic feasibility and environmental sustainability of sugarcane-based biorefineries by converting waste into renewable energy and biofertilizers.