Biofiltration for Reducing Methane Emissions from Modern Sanitary Landfills at the Low Methane Generation Stage

摘要

The performance of a lab-scale model biofilter system was investigated to treat CH₄ gas emitted from modern sanitary landfills using landfill cover soil as the filter bed medium. From the batch experiment to measure the influence of moisture content and temperature of the filter medium on CH₄ removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10–15% by weight and 25–35°C, respectively. From the model biofilter experiment to measure the influence of inlet CH₄ concentration and landfill gas inflow rate on CH₄ removal capacity of a biofilter system, it was found that the removal percentage of CH₄ increased as the inlet CH₄ concentration decreased. Up to a landfill gas inflow rate of 1,000 mL min−1 (empty bed retention time = 7.7 min), the CH₄ removal efficiency of the biofilter was able to reach 100%. Up to CH₄ loading rate of 278.5 g CH₄ m−3 h−1, the ratio of elimination capacity to CH₄ loading rate was 1 while they were 0.68 and 0.34 at CH₄ loading rate of 417.8 and 557.1 g CH₄ m−3 h−1, respectively. The CH₄ removal by biofilter was also confirmed by measuring the change of temperature and moisture content of the filter medium in the model biofilter. The results demonstrated that the installation of a properly managed biofilter system should be effective to reduce atmospheric CH₄ emissions from modern sanitary landfills at the low CH₄ generation stage.