Enhancing Biogas Purification Efficiency Through Microbial Intervention: A Comparative Analysis of Carbon Dioxide and Hydrogen Sulfide Removal in Anaerobic Digestion Systems

Biogas purification remains a significant challenge in renewable energy production. This study investigates the application of Effective Microorganisms (EM) for biogas refinement, focusing on the removal of carbon dioxide (CO2) and hydrogen sulfide (H2S). A novel experimental setup utilizing polyethylene terephthalate (PET) bottles was designed to produce and purify biogas. The system incorporated an anaerobic digester, raw biogas storage, and purification components including shock dose and maintenance dose reactors containing EM solutions at various concentrations (1%, 5%, and 10%). Over a 60-day period, biogas production and purification were monitored. Results showed that the 10% EM setup consistently demonstrated the highest removal efficiency for CO2 and H2S, followed by the 5% and 1% EM setups. The control setup using water scrubbing exhibited decreasing efficiency over time. While the control setup achieved the highest methane concentration in purified biogas (78.94<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup>), the EM setups showed superior performance in removing impurities. The study highlights the tradeoff between impurity removal and methane retention, emphasizing the need to balance these factors for optimal biogas quality and energy efficiency. The EM setups also influenced methane production patterns, with peak production occurring after an initial 13-day growth phase. This research contributes to our understanding of microbial interventions in biogas refinement and their implications for improved biogas production and purification. The findings could have significant implications for developing sustainable, cost-effective, and environmentally friendly biogas refinement technologies, particularly for small-scale and household applications.