Evaluation of cattle manure state on biogas production: a low-cost-oriented approach

This work uses a low-cost approach to study the effect of the physical conditions of cattle manure (dry and wet manure) on biogas production yield. In this research, two biodigesters were installed based on a 20-L bidon containing dry and wet cattle manure, respectively. All the bidons were coupled to a transparent plastic hose to pass the gas. A "U" shaped manometer was made through the graduated flexible plastic silicone tube to measure the amount of gas produced by the water displacement in the tube. As the water moved in the pipe, the difference between the gas produced by the dry manure and the wet manure was estimated. The effect of temperature and pH on biogas production in biodigesters was also evaluated. The flammability test was also done in proximity to the gas produced by the flame. The results show that dry cattle manure resulted in a larger biogas production, having moved the water inside the manometer until reaching a volume of 120 mL at a temperature of 34 °C and pH of 7.51 than wet cattle manure, with a maximum value of 15 mL of water displacement for the gas produced at 29 °C and pH of 7.38. The flammability test revealed a higher and more stable flame using dry cattle manure than wet. This study allows for expanding the accessibility of biogas production technology in society and encouraging the use of locally available raw materials to increase the rate of production of this gas, thus promoting the concept of sustainability in the use of resources.