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

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 degrees 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.