Effect of Bio-activator Addition and Stirring on Biogas Production from Rice Husks and Cow Dung

¹ Environmental Engineering Department, Faculty of Engineering, Hasanuddin University, Makassar - Indonesia
² Mechanical Engineering Department, ATI Polytechnic Makassar, Makassar - Indonesia

^* Corresponding author: asiyanthi@unhas.ac.id; asiyanthi@gmail.com

Abstract

Indonesia as the world’s third-largest paddy producer generates abundant agricultural wastes. Approximately, 20% of those wastes obtained in the rice milling process are rice husks that have not been fully utilized. Rice husks contain cellulose, hemicellulose, and lignin. Therefore, it can be used as an alternative source of energy. In addition, an increase in the cattle population has increased the waste produced. Disposal of livestock manure, that has not been handled properly, has caused environmental pollution. The abundance of cow dung is an energy potential which is very beneficial for the community. Therefore, rice husk, cow dung, and bio-activator EM-4 were used as the main material in this study. The objectives of this study were to analyze the volume of biogas produced from (1) each composition of rice husk and cow dung, (2) addition of bio-activator EM-4, and (3) the amount of stirring in the digester. The ratio of rice husk and cow dung waste is 70%: 30% with a solid and water ratio of 10%: 90% and 20%:80%. The addition of EM-4 and stirring frequency is made with various composition aimed to accelerate the rate of increase in biogas, which can be used as alternative energy in society.