Example of measurement of landfill gas concentration distribution and generation at a final waste disposal site

Abstract

The relationship between landfill gas concentration and landfill gas generation was clarified by measuring the landfill gas concentration (sum of methane and bicarbonate concentrations) and landfill gas velocity at the vent pipe in a final waste disposal site where landfill has been completed. It was found that the methane concentration at the outlet air vent of the gas discharge pipe tended to be higher in plots with a shorter period of time since the end of the landfill. The percentage of methane concentration by level at the ventilation pipe outlet showed that the number of ventilation pipes with a methane concentration of less than 5% increased by 50%, from 29% in 2006 to 79% in 2023, indicating that stabilization is progressing. The distribution of carbon dioxide concentration in the gas extraction pipes was classified as flat or curved, with the flat type having the largest amount of landfill gas generation and the curved type having the smallest amount.Furthermore, it was found that the landfill gas concentration must be at least less than 1% in order to satisfy the abolition criterion of less than 1L/min for landfill gas generation.