Numerical simulation of gas emission in a sanitary landfill equipped with a passive venting system

The gas emission in a sanitary landfill equipped with a passive venting sys tem was investigated numerically. The Darcy's law was employed to simulate the gas flow in the landfill. We used the first order biodegradation rate i n modeling the waste biodegradability. The results show that more than 43.3 % gases produced from the waste will emit from the landfill surface for R = 30 m, where R is the half of the well spacing. These indicate that the inf luence radii (between 30 to 50 m) were overestimated in the designing of th e gas collection systems in the Sanjuku and the Taichung City sanitary land fills in Taiwan. This might pose a potential of air pollution and raise cha nces of fires under such designing.