Operation optimization of Thiobacillus thioparus CH11 biofilter for hydrogen sulfide removal

Members of the autotrophic species, Thiobacillus thioparus CH11, were isolated from swine wastewater and immobilized with Ca-alginate to produce pellet packing materials for a novel biofilter system that controls hydrogen sulfide emission. The effect of operating parameters, including retention time, temperature, and inlet gas concentration, on the removal efficiency and capacity was evaluated. Criteria necessary for a scale-up design of the biofilter were established and the sulfur balances at various loadings were tabulated. High and satisfactory H₂S removal efficiency levels were maintained during operation and the optimal retention time was found to be 28 s corresponding to a H₂S removal efficiency greater than 98%. The pH drop was insignificant in this biofilter. The optimal inlet S-loading can be noted as 25 g m^-3 h^-1 that is at the upper end of linear correlation between inlet loading and removal capacity. We suggest that the Thiobacillus thioparus CH11 immobilized with Ca-alginate is a potent method to control hydrogen sulfide emissions.