PRODUCTION OF BIOGAS FROM GROUNDNUT SHELL (Arachis hypogaea) CO-DIGESTED WITH COW DUNG THROUGH ANAEROBIC DIGESTION

Abstract

Biogas is an alternative eco-friendly renewable energy source that produced by methanogenic bacteria through anaerobic digestion of organic materials. In this research, biogas production from co-digestion of the cow dung (CD) and groundnut shell (GS) with five mix ratios (T1 100%CD,T2 75%CD+25%GS,T3 50%CD+50%GS,T4 25%CD +75%GS,T5 100%GS) was evaluated under mesophilic conditions (38ºC) using batch fermentation for 21 days. The substrates were prepared with different total solid percentage such as 4, 6, and 8%. In all the treatments, physico-chemical parameters such as total solid (TS), volatile solid (VS), % organic carbon, nitrogen and pH were measured before and after digestion. The daily biogas production was subsequently measured by water displacement method for 21 days. The results were revealed that all measured physico-chemical parameters were significantly varied between before and after AD. As per the experimental results 8 % total solid with mixed ratio of 75%CD + 25%GS showed the maximum reduction of volatile solids and total solid content was observed. There was a significant difference in % organic carbon reduction was observed in between before and after AD. On the other hand, in all the treatments % of organic nitrogen content were increased after anaerobic digestion. In addition to this, C/N ratios were analyzed, the results were revealed that highest C/N ratio was observed in 8% total solid with 100% CD and lowest value in 8% total solid with 100%GS. Among the different proportion of the total solid, 8%, total solid with mix ratio of 25%GS+75%CD showed highest production of biogas compared with all other treatments. Over all the results of this study indicate that the increase in biogas yield and reduction in volatile solids and total solids can be significantly enhanced when cow dung (CD) is co-digested with groundnut shell in 75%:25% mix ratio.