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Abstract Due to its toxicity and corrosiveness, removal of hydrogen sulfide (H2S) from landfill biogas is essential in terms of environmental impacts and biogas valorization. This study evaluates the performance of a chemical-biological oxidation process for the purification of biogas. The treatment process consists of two separate phases. The first phase targets the elimination of 50 ppmv H2S concentration from the gaseous stream by ferric sulfate solution in the chemical absorption/oxidation reactor. This technique was 100% efficient for removing the H2S at 15 g L−1 ferric iron concentration and empty bed residence time of 7 min. The model validation indicated that the mass transfer limitation is the rate-determining phase in the chemical treatment process. Then, in the second phase, biological oxidation of the produced ferrous sulfate into ferric sulfate took place. The oxidation rates of up to 1 g Fe2+ L−1 h−1 and 0.8 g Fe2+ L−1.h−1 were achieved in the biological oxidation process with and without adding 0.1% w/v glucose, respectively.

Hydrogen sulfide (H 2 S) is one of the main contaminants found in biogas, which is one of the end products of the anaerobic biodegradation of proteins and other sulfur-containing compounds in solid waste. The presence of H 2 S is one of the factors limiting the valorization of biogas. To valorize biogas, H 2 S must be removed. This study evaluated the performance of a pilot-scale biotrickling filter system on H 2 S removal from landfill biogas. The biotrickling filter system, which was packed with stainless-steel pall rings and inoculated with an H 2 S-oxidizing consortium, was designed to process 1 SCFM of biogas, which corresponds to an empty bed residence time (EBRT) of 3.9 min and was used to determine the removal efficiency of a high concentration of hydrogen sulfide from landfill biogas. The biofiltration system consisted of two biotrickling filters connected in series. Results indicate that the biofiltration system reduced H 2 S concentration by 94 to 98% without reducing the methane concentration in the outlet biogas. The inlet concentration of hydrogen sulfide, supplied to the two-phase bioreactor, was in the range of 900 to 1500 ppmv, and the air flow rate was 0.1 CFM. The EBRTs of the two biotrickling filters were 3.9 and 0.9 min, respectively. Approximately 50 ± 15.7 ppmv of H 2 S gas was detected in the outlet gas. The maximum elimination capacity of the biotrickling filter system was found to be 24 g H 2 S·m −3 ·h −1 , and the removal efficiency was 94 ± 4.4%. During the biological process, the performance of the biotrickling filter was not affected when the pH of the recirculated liquid decreased to 2–3. The overall performance of the biotrickling filter system was described using a modified Michaelis–Menten equation, and the K s and V m values for the biosystem were 34.7 ppmv and 20 g H 2 S·m −3 ·h −1 , respectively.