Oxidation of hydrogen sulfide in biogas using dissolved oxygen in the extreme acidic biofiltration operation

► We investigated the operation of extreme acidic biofilter that used dissolved oxygen. ► RSM was used in experimental design to give relationship models among key operational parameters. ► The model of H2S removal efficiency has high reliability with R2 0.882. ► CH4 content in the outlet biogas increased because no air-mix into the biogas. ► Acidithiobacullus sp. was predominant in the consortia of this extreme acidic condition.