In-vessel aerobic composting with leachate recirculation and biochar for enhanced compost quality

Abstract. The increasing generation of municipal solid waste emphasizes the critical necessity for effective waste management strategies, particularly given that a significant fraction of municipal solid waste comprises biodegradable materials that are amenable to composting. The study investigated the potential impact of leachate recirculation, preheating, and biochar as a bulking agent on in-vessel aerobic composting efficiency. Four setups (T1 to T4) were tested over 30 days: T1 (control), T2 (with bulking agent), T3 (bulking agent + preheating), and T4 (bulking agent + preheating + leachate recirculation). The results revealed that T4 significantly enhanced the composting process, leading to a 45% reduction in Total Organic Carbon and a decrease in the C/N ratio from 28:1 to 17:1. Additionally, T4 maintained an optimum pH of 7.6 and moisture content of 55%, conditions favourable for microbial activity. Leachate recirculation in T4 also minimized phosphorus loss (40.75%) and potassium loss (63.31%) compared to the control. These studies show the effectiveness of integrating leachate recirculation, preheating, and biochar as bulking agents to accelerate organic matter degradation and produce nutrient-rich, stable compost.