The present study aimed at maximizing the performance of a standard biotrickling filter (BTF) devoted to the treatment of CH 4 at low concentrations by enhancing the mass transfer using optimum liquid recycling rates and an innovative gas recycling strategy. Internal gas recycling favored CH 4 abatement in the early stages of BTF operation and supported stable elimination capacities (ECs) above 30gm −3 h −1 at an empty bed residence time of 4min and a liquid recycling velocity of 5mh −1 higher than most ECs achieved in single phase BTFs to date. The BTF exhibited a high microbial diversity (Shannon–Wiener indices of 2.5–2.8) dominated by Type I methanotrophs, likely due to the presence of high Cu 2+ concentrations. Mass transfer limitations from the aqueous phase to the microorganisms, attributed to biomass accumulation in the packing material, were identified under the long term operation.