Hydrogen sulfide removal using granular activated carbon biofiltration inoculated with Alcaligenes faecalis T307 isolated from concentrated latex wastewater

A novel biofiltration of pure culture was developed for H2S removal from synthetic biogas using Alcaligenes faecalis T307 immobilized on granular activated carbon (GAC) as packing materials. The effect of operating parameters, including inlet H2S concentration, H2S flow rate, air flow rate, and height of media on the removal efficiency, was evaluated, together with a product analysis during long-term operation. Besides, the kinetics analysis of biofiltration was also studied. The experiment was performed in three biofilters. Biofilters A and B were packed with 20 and 40 cm of A. faecalis T307 immobilized GAC, respectively. Biofilter C as a control set was packed with 40 cm of the GAC without cell immobilization. The result showed that H2S removal efficiency of biofilters with A. faecalis T307 immobilized GAC was higher than 95% at high inlet concentrations (200–4000 ppm). Moreover, the complete H2S removal (100%) was found in biofilters A and B at H2S and air flow rate of 35 and 5.86 l h−1, respectively. Product analysis of biofilters with A. faecalis T307 immobilized GAC was performed during the long-term operation (60 days). It was found that the major product was elemental sulfur and there was only a little of sulfate ions formed. In addition, the height of media did not significantly affect the H2S removal efficiency when the oxygen was sufficient at air flow rate of 5.8 l h−1. Furthermore, in kinetic analysis, the maximum removal rate and saturation constant of H2S were calculated to be Vm = 1.1 kg m−3 s−1 and Ks = 5.2 g m−3, respectively.