A lab-scale biofiltration system for mitigating diluted methane emissions.

Methane (CH4) is a potent greenhouse gas with a global warming potential 27-30 times greater than CO2. Diffuse sources such as livestock facilities, landfills, and coal mines emit methane at low concentrations (<5% v/v), limiting the applicability of conventional mitigation technologies. Biofiltration, which uses methanotrophic bacteria to oxidize CH4 to CO2, offers a sustainable alternative but lacks standardized hardware, resulting in inconsistent designs and limited reproducibility. We present an open-source, modular lab-scale biofiltration system optimized for continuous operation and experimental replication. The system comprises triplicate packed-bed columns constructed from chemically resistant materials, integrated with mass flow controllers for precise gas delivery, humidifiers to maintain moisture, and standardized fittings for leak-free assembly. Its transparent columns enable visual monitoring, and the bottom-up flow design minimizes media compaction. Validation at an inlet concentration of 0.5% CH4 achieved mean removal efficiencies of 89.0 ± 6.7%. Design files, bill of materials, and assembly instructions are provided under a CERN OHL license to facilitate adoption and customization. This hardware supports methane mitigation research and broader applications in gas-phase bioprocessing, enabling reproducible studies and accelerating development of scalable biofiltration technologies.