What is the main operational difference between horizontal and vertical landfill gas collection wells?

The main operational difference between horizontal and vertical landfill gas collection wells lies in the area of influence and the method of installation. Vertical wells extract gas from a relatively small, cylindrical area surrounding the well, requiring a greater number of wells to effectively capture gas from the entire landfill. Horizontal wells, on the other hand, extract gas from a larger, more linear area, potentially reducing the number of wells needed, especially in areas with complex geometry or where vertical drilling is difficult. Installation methods also differ significantly; vertical wells are drilled vertically into the landfill, while horizontal wells are typically installed by trenching or directional drilling, allowing them to be placed at specific depths and along specific contours within the waste mass. Horizontal wells are often used in areas with steep slopes or where there is a shallow depth to groundwater, making vertical well installation problematic. While vertical wells are simpler and less expensive to install initially, horizontal wells can offer improved gas collection efficiency and reduced long-term maintenance costs in certain situations. Vertical wells are typically used in new cells, whereas horizontal wells are often installed in closed or existing landfill areas.