Efficacy of Organic Nutritive Additives on the Quantity and Fuel Value of Biogas from Donkey Dung as Alternative Source of Gaseous Fuel

Abstract

Five (5) different slurries of donkey dung were prepared by dissolving 20.00g of ground donkey dung in 125.00cm³ distilled water. Each of the slurries was placed in a 500cm³ Buchner flask (as a reactor).The reactors were made in triplicate and, labeled A, B, C, D and control. A quantity of 0.15g each of blood meal (as source of proteins), ethanoic acid, ground nut oil and sugar was added to A, B, C and D, respectively while the control reactor was kept unaided (without additive).  The slurries were subjected to anaerobic  microbial decomposition at 33^oC for 30 consecutive days.  The biogas (gaseous product) generated in each reactor was collected over brine (28% NaCl) and, the average daily and total volumes of biogas for each reactor was purified by absorption process using appropriate absorbents and subsequently dried by passing over activated silica gel.  The work showed that the mean total volumes of the gaseous product collected from A, B, C, D and control reactor were 49.52dm³, 49.66dm³, 49.88dm³, 52.44dm³ and 48.52dm³, respectively; the percentages of the fuel contents of the mean total columes of biogas collected (based on the respective CH₄ contents of the gaseous products) from A, B, C, D and control wee 60.78%, 60.62%, 60.42%, 64.75% and 60.39%, respectively; the increase in the volumes of the gaseous product in A, B, C and D were 1.00dm³, 1.14dm³, 1.36dm³, and 3.02dm³, respectively and; the percentages of the increase in the fuel value in A, B, C and D were 0.39%, 0.23%, 0.03%, and 4.36%, respectively.

Keywords: Donkey dung; organic nutritive additives; biogas; gaseous fuel;   fuel value.