Comparison on the removal of hydrogen sulfide in biotrickling filters inoculated with Thiobacillus thioparus and Acidithiobacillus thiooxidans

Emissions of hydrogen sulfide (H₂S) by industrial activities is frequent cause of corrosion and unpleasant odours. Treatment of gaseous emissions contaminated with H₂S by biotrickling filters inoculated with single cultures of sulfur oxidizer bacteria exhibit several advantages over physicochemical methods, such as shorter adaptation times and higher removal ability. Biofilms of Thiobacillus thioparus and Acidithiobacillus thiooxidans have proved to exhibit high removal capacities, yet no comparative studies between them have been reported. This article reports the efficiency of biotrickling filters inoculated with T. thioparus and A. thiooxidans under similar conditions excepting the pH, that was the optimal for the bacterial growth, for the removal of H₂S. The support was selected by determining the respirometric coefficients of the biomass. The maximum removal capacity of the biofilter inoculated with T. thioparus, operating within the range of pH (5.5-7.0) was 14 gS m^-3 h^-1, lower the value obtained for the biotrickling filter inoculated with A. thiooxidans; 370 gS m^-3 h^-1. Therefore, it is concluded that acid biotrickling filter inoculated with A. thiooxidans constitute the best strategy to remove H₂S, with the advantage that the system not require an exhaustive pH control of the liquid media.