Hydrogen sulfide removal in biotrickling filter system by Halothiobacillus neapolitanus

Hydrogen sulfide (H2S) in biogas, is both toxic and damaging to the environment, to the human health, and also damages machines and engines by contributing substantially towards corrosion. It can be removed from the biogas before being used by utilizing biological or physiochemical processes. A new bacterial strain of obligately chemolithoautotroph, Halothiobacillus neapolitanus NTV01 (HTN) with ability to remove H2S from gas stream was screened, purified, and inoculated in a biotrickling filter system with counter current gas/liquid flows. Maximum sulfur oxidation activity and cell growth were found in the culture medium consisting of 10 g/L of thiosulfate and 52 mM phosphate buffer pH 7. HTN is able to tolerate higher sulfate concentrations (8.35 g/L) than reported previously. In the biotrickling filter operation with biogas fed to the system, pH appeared to be a highly important factor to affect the H2S removal. Liquid recirculation required a fresh replacement every 48 h and controlled pH 7 to achieve the optimum performance of H2S removal. H2S was efficiently removed 95–100% when the initial concentration in the range of 45–255 ppmv.