Keywords: agricultural waste, anaerobic digestion, biogas, greenhouse gases, global warming, Jatropha curcas seed cake, methane, organic loading rate
Optimum organic loading rate for semi-continuous operation of an anaerobic process for biogas production from Jatropha curcas seed cake
This paper reports on biogas production by anaerobic digestion of Jatropha curcas seed cake in semi continuous flow at 30°C, focusing on increasing the organic loading rate (OLR) of seed cake by investigating levels of 1.25, 1.67, 2.5, 3.33 and 5 kg Chemical Oxygen Demand (COD)/m³ day. Reactors were fed at flow rates of 125, 167, 250, 333 and 500 ml/day, yielding Hydraulic Retention Times (HRTs) of 40, 30, 20, 15 and 10 days. Increasing the OLR decreases the organic digestion. The highest methane yield (340 l at STP/kg COD degraded) was obtained at the OLR of 1.25 kg COD/m³ day.