Field-scale operation of methane biofiltration systems to mitigate point source methane emissions

Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH(4)). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH(4) to carbon dioxide (CO(2)) and water (H(2)O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH(4) emissions using an MBF at a natural gas monitoring station. A new comprehensive three-dimensional numerical model was developed incorporating advection-diffusive flow of gas, biological reactions and heat and moisture flow. The one-dimensional version of this model was used as a guiding tool for designing and operating the MBF. The long-term monitoring results of the field MBF are also presented. The field MBF operated with no control of precipitation, evaporation, and temperature, provided more than 80% of CH(4) oxidation throughout spring, summer, and fall seasons. The numerical model was able to predict the CH(4) oxidation behavior of the field MBF with high accuracy. The numerical model simulations are presented for estimating CH(4) oxidation efficiencies under various operating conditions, including different filter bed depths and CH(4) flux rates. The field observations as well as numerical model simulations indicated that the long-term performance of MBFs is strongly dependent on environmental factors, such as ambient temperature and precipitation. (C) 2011 Elsevier Ltd. All rights reserved.