PRODUCTION OF BIOGAS FROM Ricinus communis L. Leaves THROUGH ANAEROBIC CO-DIGESTION WITH COW DUNG

Abstract

Production of biogas through anaerobic digestion of organic waste materials provides an alternative eco-friendly renewable energy source. With the aim of biogas production from codigestion of Cow dung and Ricinus communis leaves, a series of experiments were carried out under mesophilic conditions at 38 ºC using batch fermentation for 30 days. Anaerobic fermentation were carried out by mixing the substrates in five different proportions to obtain suitable mix ratio for maximum biogas production from co-digestion of Cow dung with Ricinus communis leaves having 8% TS. All measured of physico-chemical parameters of each substrate significantly varied between before and after anaerobic digestion. The results indicated that, highest pH value, percentage of total and volatile solid was observed in treatment with 100% CD, whereas the lowest values was observed in 100% RCL with the same percentage of total solid content. Before the anaerobic digestion the pH values of all substrate types were in the range of 6.80 to 7.16. Comparison of pH values after anaerobic digestion showed that it significantly increased for all treatments. Moreover, total solid and volatile solid content were decreased after anaerobic treatment as compared to before anaerobic digestion. In addition to this, organic carbon, total nitrogen and carbon to nitrogen ratios were analyzed, the results revealed that highest organic carbon (45.10±.001), TN (1.78±.001) and C: N (25.34:1) ratio were observed in 100% RCL and lowest value in 100%CD before AD. During the assessment of cumulative biogas production revealed that the substrate in a mix ratio of 1:3 CD and RCL showed the highest (2054.13ml) biogas production, suggesting this mix ratio of the two substrates is an optimal to yield better amount of biogas. From this experimental study the result showed that co-digested substrates of the three mix ratios (i.e. B, C and D) produces higher amount of biogas than the two individual substrate (E and A).