Effect of temperature and pH variation on anaerobic digestion for biogas production

Abstract

A comparative analysis study of pH and temperature effects on the anaerobic digestion process of different agricultural wastes was carried out during the production of biogas. The investigation was in two phases. Phase one involved the use of a single substrate of cow dung, cassava peels, yam peels and pineapple peels while the second involved co-digestion of the substrates with cow dung. The composition of gas produced by a single substrate and a mixture of these substrates were determined. The feedstock for each experiment was a 1:1 mixture of the substrates with water. For the co-digestion, one part of the substrate and one part of cow dung were used with two parts of water, making the ratio 1:1:2. Routine measurements of pH and temperature of the feedstock were taken and the composition of the produced biogas was determined. It was deduced that cow dung co-digested with cassava peels gave a higher yield with methane content of 65.3% followed by cow dung only, co-digestion of cow dung and yam peels, cassava peels only, yam peels only and pineapple peels with 63.4%, 51.4%, 46.2%, 42.3% and 0.0%, respectively. Therefore co-digestion, with cow dung and cassava peels is most efficient for biogas production.