Effects of Green Bio-Catalysts and Ferric Oxide in Cryo-Mesophillic Temperature Biogas Production

Abstract

Biogas production at low temperature regimes is annoyingly slow and yields low biogas volumes. Most biogas supplements are expensive and substrate-specific. The effects of two bio-catalysts Saccharomyeces spp. and Acanthaceae spp. and an inorganic catalyst ferric oxide on biogas production using cow dung slurry was investigated. 1.5L batch anaerobic digester operating in unstirred cryo-mesophilic temperature regime of 20.0 -24.5 0C were utilized. The substrate underwent mild synergistic pre-treatment by steaming with 1% sodium hydroxide solution. The alkalinity and volatile acids of the substrates were insignificantly perturbed by inclusion of the additives. Additives Saccharomyeces spp. and Acanthaceae spp. stabilized digestion temperature while ferric oxide stabilized pH drifts. The overall biogas yields produced in the 100-day retention period were in the order of 4615ml (990.34ml/g-Volatile solids) for ferric oxide, 2335ml (494.08ml/g-Volatile solids) for Saccharomyeces spp., 1750ml (328.94ml/g-Volatile solids) for Acanthaceae spp. and 1030ml (212.37ml/g-Volatile solids) for the control sample. Use of these additives would thus optimize biogas production in cold countries.