Study on reclamation method for a sanitary landfill with environmental problem by semi-aerobic structures

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This research examines to measure temperatures and landfill gas components in passive landfill gas extraction wells of a closed landfill and evaluate the effect of the wells for accelerate the stabilization of the landfill. Several wells show the high temperature profile and low methane gas concentration. Especially the temperatures rose up to 60 degrees and high concentration of carbon dioxide was detected. This means active aerobic biodegradation occurred. Then the temperature declined and the gas composition was 71% of nitrogen and 29% of oxygen (like as the air). So the area around this well has stabilized. However, most of the wells show the high concentration of methane (more than 10%) and low temperatures (less than 25 degrees) and anaerobic biodegradation is dominant. Through observations of temperatures and landfill gas components passive landfill gas extraction wells hardly contribute to active aerobic biodegradation in this landfill body. Landfill gas profile in several wells shows the higher concentration of methane and the lower concentration of oxygen in vertical direction.Finally landfill gas transport phenomena simulated by numerical method. The method includes convection, diffusion and generation of landfill gas. Landfill gas profile is well presented by this simulation. The well may contribute to extraction of landfill gas generated in the landfill body. Nearly 10m in radial direction is the area of landfill gas collection by the well. The simulation shows the concentration of methane may decrease and the concentration of carbon dioxide may increase by the well.