Abstract
The aim of this paper was to investigate the effect of yeast on the biomethane yield of an anaerobic digester with cow dung feedstock. The biochemical methane potential (BMP) test was conducted on three different substrates for the production of biomethane. The BMP test was carried out using batch digesters at a temperature of 37 ℃. The substrates were divided into three parts: cow dung alone, yeast alone and the last involved the digestion of the mixture of cow dung and yeast. The maximum volume of the biomethane produced was observed from the samples containing yeast alone with a volume of 675.97 Nml Biogas/g VS. The lowest volume of biogas occurred on the samples containing the mixture of cow dung and yeast with 15 g of yeast and had a volume of 266.0 Nml Biogas/g VS. The sample containing cow dung alone produced a volume of 364.29 Nml Biogas/g VS. The results obtained for the digestion of yeast alone indicated that the higher yield of biogas was obtained when little amount of yeast was added on the substrate and that the addition of yeast on the anaerobic digestion of cow dung improves the yield of biogas; with the optimum biogas yield occurring at the ratio of 1:2 (yeast: cow dung).