The effects of crude glycerol addition on biogas production

Abstract

Abstract Crude glycerol is a by-product of biodiesel production in which the number increases every year and is quite an expensive purification process to meet the technical standards required by consumer industries. To overcome this, it is important to find alternatives for crude glycerol utilization to increase the economic feasibility of the biodiesel industry. This study aimed to evaluate the technical feasibility of biogas production with the addition of crude glycerol from a Palm Oil Plant. The glycerol was introduced into 500mL Anaerobic Digester (AD) as a carbon source and energy source for the growth of methanogenic bacteria along with cow dung and Distilled Water with a ratio of 1:1. The addition of crude glycerol was 5% wt (GL5), 10% wt (GL10) dan 15% wt (GL15), and one control reactor without crude glycerol addition (GL0). AD was operated in a batch system at mesophilic conditions for 30 days. The highest biogas yield was obtained in the experimental set GL10 as much as 380 mL/g VS and was formed on the 3rd day but the highest percentage of methane gas (CH4) was obtained from the control set GL0 as much as 60.2%. In addition to the identification of bacteria, it was found that the type of Bacillus sp in the GL10 treatment was the most biogas producer, and based on the results of its bio-slurry analysis it could be used as organic fertilizer and soil improvement for agriculture and degraded soil.