Abstract:
Energy is one of the most important factors for human development and to global prosperity.Biogas is a versatile renewable energy source, which can be used for replacement of fossil fuels in power and heat production. Therefore, this research was initiated to utilize biomasses such as Vernonia auriculifera leaves (VA) and cow dung (CD) for biogas production. In this study, biogas production from co-digestion of the VA and CD in five mix ratios (100% VA, 70% VA: 30% CD, 50% VA: 50% CD, 30% VA: 70% CD and 100% CD mix) were evaluated by incubating at 38º using batch fermentation after the substrates were pre-treate with temperature of 600C and 80°C separately. . In all treatments, physico-chemical parameters such as total solid (TS), volatile solid (VS), organic carbon, total nitrogen, carbon to nitrogen ratio and pH were measured before and after anaerobic digestion (AD). The daily biogas production was subsequently measured by water displacement method for 30 days. Higher daily mean biogas amount was produced at day 11th and 12th for all substrates which were thermally pre-treated under 80 and 60°C, respectively and went down to zero at about the 30th days almost in both thermal pre-treated substrates. Out of the five treatments, treatment 4 (T4=70% CD: 30% VA mix ratio) has produced high cumulative amount of biogas in both 60 and 80°C thermal pre-treatments (1112.22 and 1383.79 mL, respectively). Better cumulative biogas yield was observed on the treatments pre-treated under 80°C than 60°C. Highest reductions of TS (18.39%) and VS (9.87%) were recorded in T4 pre-treated at 80°C. The result also revealed that impact of temperature pre-treatments on biogas yield of vernonia auriculifera leaves co-digested with cow dung in anaerobic condition. Generally, the T4 was the best mix among all other treatments which produced high cumulative biogas in 80°C thermal pre-treatment (1383.22 mL).
