Identification of Sulphur Oxidizing Bacteria on Charcoal Made of Salak Fruit Seeds for Hydrogen Sulfide Removal in Biogas

Abstract

Alternative energy sources to substitute fossil fuels have been developed, biogas being one of them. However, H2S needs to be removed in biogas because it promotes corrosion in the equipment using biogas. The H2S can be removed from biogas by biological processes. H2S was removed by biofiltration, in which H2S degrading bacteria immobilized on the packing material inside a column. This study aimed to determine the genera of microorganisms that degrade H2S in biogas. Moreover, this research aimed to investigate the ability of these microorganisms to degrade H2S. The novelty of this research is the use of charcoal from salak fruit seed as a packing material for immobilization the microorganisms in the biofilter; therefore, the packing material is more durable and does not rot. The isolated sludge taken from liquid wastewater treatment in the tofu industry was tested for sulfide degradation. Then, the best of bacteria to degrade sulfide was immobilized on the surface of charcoal made of salak fruit seeds and after acclimatization and the bacteria grew well. We tested their capability of forming biofilms on the surface of the charcoal of salak fruit seeds. Further identification showed that the isolate was Bacillus cereus with a similarity value of 98%. An experiment to remove H2S of biogas using a biofilter column with immobilized Bacillus cereus bacteria on the surface of the charcoal of salak fruit seeds showed that the Bacillus cereus bacteria could degrade H2S of biogas that flew in the biofilter through the surface of charcoal of salak fruit seeds. The highest removal efficiency was obtained for H2S (RE) at the packing height of 80 cm; 97.15% of which was achieved at a biogas flow rate of 30 L/hour, the H2S concentration was 142.48 ppm for 4 hours.