A critical review of prospects and operational challenges of microaeration and iron dosing for in-situ biogas desulfurization

Abstract

Anaerobic digestion is a widely used waste valorization method that produces methane-rich biogas. Notably, biogas upgrading to renewable natural gas has attracted considerable attention. However, extensive desulfurization is required for its upgrading due to the presence of various impurities like hydrogen sulfide and volatile organosulfur compounds in biogas. Recently, in-situ biogas desulfurization technologies, particularly microaeration and iron dosing, have received significant attention, with a few successful full-scale demonstrations. A few reports suggested that these two technologies can be economically competitive with ex-situ biogas desulfurization technologies. This article comprehensively reviews the in-situ desulfurization efficiency of these processes during AD. This review covers mechanisms and desulfurization pathways, process parameters, process control, and operational challenges of these technologies. Moreover, the economic feasibility of microaeration and iron dosing approaches were highlighted. Finally, based on the literature review, key research gaps, challenges, and future research perspectives are outlined to guide the prospects for future studies.