Removal of H2S in biogas using biotrickling filter: Recent development

The presence of hydrogen sulfide (H2S) in biogas negatively affects human health and corrodes metal. Therefore, the removal of H2S from biogas before using is an essential requirement in many cases. Recently, biotrickling filters (BTFs) have been widely applied to the treatment of H2S on both laboratory and industrial scales. However, BTFs method also has some drawbacks such as low mass transfer efficiency, clogging the bed filter due to further elemental sulfur (S) excess accumulation, and biogas dilution. This paper reviews the recent development of aerobic BTF systems and solutions for those limitations during the H2S oxidation process in biogas. In addition, the factors affecting H2S removal efficiency, including sulfur-oxidizing bacteria, biofilm, packing material, pH, dissolved oxygen (DO), empty bed retention time (EBRT), ingredients of nutrients for the growth of bacteria, trickling liquid and gas velocity, are also discussed. Finally, the current strength of research in the field of H2S removal in biogas using BTF and its future prospects are also suggested. Some of highest elimination capacity (EC) of 78.57 g H2S/m(3)h, 144 g H2S/m(3)h, 228.6 g H2S/m(3)h were obtained from previous experiments. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.