Semi-continous anaerobic co-digestion of cow manure and banana waste: effects of mixture ratio

Anaerobic co-digestion of cow manure (CM) and banana waste (BW) was investigated. The experiments have been carried out and were tested for different mixture ratios of CM: BW in terms of volatile solids : 100: 0, 80: 20, 60: 40, 50: 50, 40: 60, 20: 80 and 0: 100 with the aim to maximize methane yield and methane production from the anaerobic co-digestion of cow manure and banana waste. The results obtained show that a maximum methane yield of 229 mL _STP/g VS added was obtained at a (CM): (BW) ratio of was 40: 60 with a biodegradability of 86% for an organic loading rate in the range of 1.49-3.57 kg waste mixture/(m³d). The pH and alkalinity for all experiments were controlled and kept within an optimum interval of 7.1-7.6 for pH and 2-4 g CaCO₃/L for alkalinity. It was shown that banana waste and cow manure could easily be degraded by anaerobic co-digestion under mesophilic conditions, resulting in methane yields sufficient for commercial production of methane.