Optimization of Process Conditions for the Production of Biogas from Cow Dung

Abstract

Biogas recovery from animal waste could be the key to unlocking the financial and environmental benefits of managing manure produced by livestock operations as well as organic waste from food processing sectors. There is no doubt that in the near future, the world’s energy supply market will be dominated by renewable and sustainable energy, since there is no alternative. While combustion is the most common method to gain energy from biomass such as wood and wood chips, the high content of water in animal slurry suits anaerobic digestion/fermentation for conversion to energy, in that direct combustion is not appropriate for most animal manures. However, biogas production is the technology that converts animal manure and other biomasses into viable fuel, recycling the carbon resource of animal slurry. This study critically evaluated the process conditions for biogas production yields from cow dung. The cow dung was pretreated and characterized, after which its proximate analysis were determined. Effects of process variables (cow dung/water ratio, catalyst dosage, and time) on the biogas yield were evaluated and optimized using the response surface methodology (RSM). The proximate analysis of the cow dung revealed that the moisture content falls within the acceptable limit of not more than 10% for long-term storage, an ash content of 5.52% was recorded; indicating a high mineral content of the cow dung sample and the volatile matter content value of 77.21% signifies the raw material suitability for biogas production. Furthermore, the results of the optimization of biogas production in this research work were found to have significance with the process parameters, thus, the optimum biogas yield of 51.97% was obtained at cow dung/water ratio of 0.46g/ml, catalyst dosage of 0.98g and time of 3days.