Patent ID: 7972082
Filing Date: 2011-07-05
Classification: B09B,Y02W

Abstract:
1. A method of collecting biogas from a landfill having waste and an outer surface contacting the atmosphere, wherein the landfill contains (i) at or near the outer surface contacting the atmosphere a gas-containment layer that has low gas permeability; and (ii) a gas-permeable layer toward the interior of the landfill from the gas-containment layer and toward the exterior of most of the landfill waste mass, the gas-permeable layer having at least 10 times the gas-permeability of the gas-containment layer; the method comprising: (a) collecting biogas from the landfill from a location toward the interior of the landfill from the gas-permeable layer with at least one gas-collection well that collects biogas from an extraction location toward the interior of the landfill from the gas-permeable layer and separated by waste from the gas-permeable layer and draws it to the surface, the well comprising a biogas-collecting wellhead at the extraction location and a conduit linking the wellhead to the surface to draw biogas from the wellhead to the surface; wherein step (a) comprises collecting biogas at a maximal rate for at least one hour and a minimal rate for at least one hour in the same day, wherein the maximal rate of biogas collection in a day is at least 20% more than the minimal rate of biogas collection in the same day for at least two consecutive days.