An investigation to compare the efficiency of landfill gas collection systems with different well numbers (one,
two or four) and configurations (vertical or horizontal) has been conducted. The study has shown that with an increasing
number of wells, the gas collection rate and efficiency are enhanced and the gas flux at the surface also becomes more
uniform. In addition, the study has also suggested that for wells with the same screen length, a vertical well works better
than a horizontal well in terms of gas extraction rate; however, it may result in a less uniform gas flux through the surface.