Biogas from Mesophilic Anaerobic Digestion of Cow Dung Using Silica Gel as Catalyst

Biogas originates from bacteria in the process of biological breakdown of organic material under anaerobic conditions. A research work was conducted to investigate the production ability of biogas from mesophilic anaerobic digestions of cow dung (CD) using silica gel as catalyst. Two laboratory scale digesters were constructed to digest cow dung, where one set-up was used for digestion of cow dung without catalyst and the other set-up was used for digestion with catalyst. The digesters were made of glass conical flask of 1-liter capacity each. Cow dung was used 390 gm and water was used 310 gm in each experiment. In the slurry, total solid content was maintained 8% (wt.) for all the observations. The digesters were fed on batch basis. The digesters were operated at ambient temperatures of 27 - 31 degrees C. The total gas yield was obtained about 27.3 L/kg CD for digestion without catalyst and about 30.5 L/kg of CD for digestion with catalyst. The retention time was about 76 days for both the digestions. The gas yields were compared with the previous work of mesophilic digestions of cow dung without catalyst of operating temperatures 18 - 28 degrees C. (C) 2015 The Authors. Published by Elsevier Ltd.