Removal of high strength hydrogen sulfide gas using a bioreactor immobilized with Acidithiobacillus ferrooxidans and a chemical absorption scrubber

To treat a waste gas containing a high strength H₂S, the two-stages microbial desulfurization process that consisted of a bioreactor immobilized with Acidithiobacillus ferrooxidans and a chemical absorption scrubber has was proposed. After 4 times repeat of batch cultures, the immobilized bioreactor has been stabilized and the rate of iron oxidation reached 0.89 kg·m^-3·h^-1 at steady state. The two-stages microbial desulfurization process was able to be operated for a long term over 54 days. The removal efficiencies of H₂S were 97-99% at a space velocity of 70 h^-1 and a inlet concentration of 37,000 ppmv. The maximum elimination capacity of H₂S was approximately 3.3 kg S·m^-3·h^-1. In the bioractor, the concentrations of the Fe³⁺ and the immobilzed cell were constantly maintained during the desulfurization.