Control of Gas Flow from Sanitary Landfills

Organic refuse materials deposited in a sanitary landfill undergo a process of decomposition that generates various gases, e.g., methane, carbon dioxide, hydrogen sulfide, etc., as well as other liquid and solid by-products. The gases of decomposition can flow out into adjoining soil formations and through the landfill cover. Methane, a major component of these gases, can form an explosive mixture with the air at volumetric concentrations of 5%–15%, and can pose serious fire and explosion hazards to buildings constructed on or near landfills. A gas control system based on forced ventilation of gases from the soil pore space is examined in this paper. Analytical solutions are presented for the flow problem and results of these solutions are compared with the observed field data. Solutions presented here can be used for determination of optimal spacing of ventilation wells based on measured flow rates and pressures in a single test well.