Biogas Quantity and Quality from Digestion and Co-Digestion of Food Waste and Cow Dung

Abstract

The aim of this study is to assess the quantity and quality of biogas produced from single substrate digestion of food waste and cow dung as well as co-digestion of food waste and cow dung. Laboratory sized 25 litre plastic biodigesters were used in this study and the digestion processes was carried out for a 30 day retention period. The results revealed that the cumulative biogas production for the single substrate digestion of cow dung was 7,975 ml, the cumulative biogas produced for the single substrate digestion of food waste was 7,742.5 ml while the cumulative volume of biogas produced for the co-digestion of cow dung and food waste was 16,482.5 ml. The results also showed that the total volume of methane produced for the single substrate digestion of cow dung was 955 ml while the total methane produced for the single substrate digestion of the food waste was 765. The total production of methane for the co-digestion of cow dung and food waste was found to be 2,655 ml. This study revealed that though the co-digestion process improved biogas quantity and quality, the percentage methane present in the biogas very low. There would be a need to stimulate the digestion and co-digestion process in order to improve the quality of biogas produced.