Assessment of temperature dynamics during methane oxidation in a pilot scale compost biofilter

Biological methane oxidation can sustain high temperatures in organic matrices, such as landfill covers and compost biofilters. This study investigates the temperature dynamics, methane removal efficiency, and microbial community responses in a pilot scale compost biofilter under three methane concentrations (2, 4, and 8 % v v^-1 in air) with a 23-minute empty bed residence time. Complete methane removal was achieved at 2 %, with compost bed temperatures reaching 51 °C. At 4 % and 8 %, temperatures exceeded 60 °C, reducing methane removal efficiency to 97 % and 75 %, respectively, with maximum removal rates of 75 g m^-3h^-1. Thermotolerant Methylocaldum dominated at temperatures above 50 °C. Elevated temperatures shifted microbial metabolism from anabolism toward catabolism, likely due to thermal stress, as indicated by outlet gas profiles. These findings highlight the importance of optimizing operating conditions, such as moisture control and heat extraction, to balance thermal performance and microbial activity for effective methane biofiltration.