Experimental investigation of biogas production by co-digestion of local vegetable market wastes

The excessive production of vegetable waste near the vegetable market poses a significant threat to the environment. The cost associated with collecting, gathering, and transporting these wastes for disposal over long distances has become prohibitively high. To address this issue, one feasible approach is to utilize anaerobic digestion of biodegradable solid waste, such as cow dung, poultry waste, food waste, and vegetable dumping, to produce methane gas as an environmentally friendly energy source. This study aims to assess the viability of biogas production from vegetable waste in the Perundurai market, located in Erode, India. The experiment was conducted using a lab-scale reactor (0.75 L) equipped with appropriate feeding, gas collection, and residue drainage mechanisms. Biogas generation from the reactors was monitored daily using the water displacement method. For a period of 45 days, the digester setup was fed a mixture of cow dung and vegetable waste with different mixing ratios of 1:1 (R1), 1.5:1 (R2), and 2:1 (R3), at a mesophilic temperature of 35 °C. The results indicated that the highest biogas yield was achieved with the R3 samples, which were approximately 3.9 and 3.0 times higher than those of R1 and R2, respectively. Similarly, the peak methane levels were found to be 66%, 58%, and 53% for R3, R2, and R1, respectively. Moreover, the degradation rate was significantly better for R3 (3.32) compared to R2 (2.93) and R1 (2.24). Based on these findings, it can be concluded that co-digestion of the considered mixtures (vegetable waste + cow dung) in a mesophilic environment could be a promising strategy to enhance biogas production while maintaining nutrient balance and digester stability. The generated biogas can be utilized for various applications, including heating, electricity generation, and as fuel for internal combustion engines, by employing a suitable biogas plant.