Variation in methane concentration produced from anaerobically digested vegetables

Anaerobic fermentation is a highly promising technology for converting biomass waste into methane, which then may directly be used as an energy source. Attempts have been made to optimize various parameters in order to determine the most favorable recipe for maximum biogas production from fermented vegetable waste. The biogas production from many types of vegetable waste such as zucchini, orange peel, tomato, potato, and rice was studied in batch digesters. The effect ofadding chicken dung and sludge to vegetable waste on the concentration of methane in the produced biogas was investigated. The experiments were conducted at room temperature (20°C) and at 35°C. The results revealed that methane concentration goes through maximum value with time. This maximum value is obtained faster when the rate of digestion is faster. The concentrations of methane in the biogas produced are ranked as follows: potato>rice>tomato>zucchini>orange peels. The concentrations of methane gas increased as chicken dung and sludge were mixed with the vegetables. Themaximum value of methane concentration is reached faster in a mixture of chicken dung and sludge. For both chicken dung and sludge, the maximum value is reached at the same time.