Mitigating methane emissions from landfills, a significant contributor to greenhouse gases, is critical for Canada’s support to the Global Methane Pledge. Passive methane oxidation biosystems (PMOBs) are considered cost-effective solutions to reduce fugitive CH4 emissions that are not captured by gas collection systems. The objective of this study was to design, construct and monitor a PMOB capable of abating fugitive CH4 emissions from a closed landfill in a cold climate environment. This thesis presents key design considerations and features, PMOB monitoring equipment and practices, and assesses the PMOB efficiency. Methane oxidation efficiencies between 73 and 100% were achieved during the monitoring period. Overall, the PMOB construction and monitoring results supported evidence that the designed PMOB was capable of abating fugitive CH4 emissions.