Experimental and kinetic studies of biogas production from petroleum oily sludge by anaerobic co-digestion with animals’ dung at thermophilic conditions

Abstract

Anaerobic co-digestion technology is widely used for biogas generation from organic wastes. In this study, co-digestion of petroleum oily sludge (POS) for biogas production in bench-scale anaerobic digesters at thermophilic conditions was investigated. The effects of inoculum type on the biogas production were considered. Three types of inoculums were examined individually for the co-digestion of POS which were; poultry manure, cattle manure, and cow dung. The results revealed that the biogas production from poultry manure, cattle manure, and cow dung exceeded its production from uninoculated POS by 64.6, 20.94 and 6.1% respectively. Effect of C/N on the co-digestion process was also considered in this study. Modified Gompertz model was applied to describe the kinetic of the co-digestion process. The predicted and experimental results of biogas generation were fitted well with coefficients of determination > 0.96 indicating appropriate conditions of the co-digestion process. Statistical analysis was performed to estimate if there were significant differences in terms of cumulative biogas yield. A significance level value of < 0.05 was obtained.