Preliminary Study on Microbial Desulfurization: Targeting H 2 S Removal from Biogas with a Bioscrubber

Abstract

Bio-desulfurization generally involves the oxidation of sulfide to sedimented, sulfur compounds in microaerobic conditions and is applied at biogas power plants by the palm oil industry. In this work, microbes were screened from various sources, including microalgae, coal waste, Palm Oil Mill Effluent (POME), and cow manure. Screening of potential microbes was conducted using synthetic chemical reagent as the sulfur source. Decomposition of sulfur sources, like Na₂S₂O₃, has been observed through microbial process whereas sulfur was separated into sedimented other sulfur compounds. Screenings were first conducted in modified growth media followed by screening with selective media for Thiobacillus. With the selective media, the treatment was continued with the addition of a sulfur source to see if the microbes are able to convert the sulfur to sulfuric acid or other sulfur compounds as sediment. The preferred microbe would be chosen and applied to the bioscrubber system at Terantam, Indonesia. This work could also be applicable to biogas generation from POME where H₂S content is more than 1,200 ppm, which is corrosive to the biogas engine. Finally, we propose a two-step desulfurization in which H₂S is absorbed by an alkali solution followed by sulfur separation.