Abstract:
Biogas is renewable energy carrier produced by anaerobic digestion of organic substrates and is
considered a Sustainable alternative to fossil based fuels. This study focused on optimizing the
production of biogas by co-digesting cow dung and wheat straw wastes. In this study, production of
biogas from wheat straw (WS) and cow dung (CD) via co-digestion process was evaluated under
mesophilic conditions using a batch digester for 35 days; which had high methane gas under optimum
temperature, pH, and substrate mix ratio. In all treatments, physicochemical parameters such as total
solid, volatile solid, moisture content, carbon to nitrogen ratio, and pH were measured before and after
digestion. The experiment for biogas production by wheat straw and cow dung wastes was conducted
using response surface methodology. Three numeric factors and three- levels Box-Behnken design expert
was employed to study the effect of wheat straw to cow dung mix ratio, pH, and temperature for
produced biogas yield. A total of 17 runs with replicates were performed. Gas production was noticed in
all of the digesters starting from day 4th of anaerobic digestion. The daily biogas production was
subsequently measured by gas syringe for 35 days and the methane gas composition was also analyzed
by a gas analyzer. Cumulative biogas production revealed that substrate in a mix ratio of 75% WS +25%
CD at pH of 7.0, and at temperature of 37.5℃ showed the highest cumulative volume of biogas
production (198mL), and composition of methane gas (62.5%) as an optimal condition. Further
researches have to be done to improve the production of high quality and quantity of production of
biogas
