EC Microbiology

This research is aimed at biogas production from bioaugmented and biostimulated animal dungs using custom-built bioreactor of 20 liter capacity in the anaerobic digestion process. Piggery and poultry dung were used as feedstock while sodium carbonate solution, Shigella flexneri, Bacillus paramycoides, bovine blood, charcoal water, magnesium sulphate solution, zinc nitrate solution, protein extract, pH 8 solution and natural water which serve as control were used as treatments. After 21 days of batch anaerobic digestion, bioreactors with NaCO₃, Shigella sp, Bacillus sp, bovine blood, protein extract, charcoal water, zinc nitrate, natural water, MgSO₄ and pH of 8 gave gas production of 80.6g, 95.5g, 100.3g, 232.2g, 63.9g, 58.3g, 7.4g, 90.0g, 139.2g and 100.0g respectively. Bioreactors with bovine blood and magnesium sulphate gave the highest gas production because the blood was nutrient-rich and the magnesium sulphate which turned the water hard encouraged wide range of bacterial growth and sustenance of pH of the reaction environment. Zinc nitrate reacted with water in the slurry to form nitric acid which turned the internal reactor environment to be acidic which doesn’t favour methanogens. Also, the gas from the feedstock amended with Magnesium sulphate, bovine blood and charcoal water showed a significant increase in methane production. The gas from the feedstock amended with charcoal gave the lowest percentage composition of carbon dioxide, which showed that the charcoal was responsible for adsorption of the carbon dioxide. This research work recommends that measured amount of bovine blood should be used to supply nutrient to the indigenous bacteria. Calculated amount of Magnesium sulphate should be used to buffer the pH. Finally, charcoal water should be used in slurry preparation to remove the ammonia and carbon dioxide by adsorption as gas production commences.

 Keywords: Biodigester; Modelling; Isolation; Fermentation; Slurry

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