A shallow gas well for use at landfills having a gas-producing waste pile includes a lower geocomposite positioned over the gas-producing waste pile and a protective layer of soil positioned over the lower geocomposite. An upper geocomposite is positioned over the protective layer of soil such that the protective layer of soil is positioned between the lower and upper geocomposites. An impermeable geomembrane is positioned over the upper geocomposite and a shallow gas well collector is positioned within the protective layer of soil.

A gas collection grid for use at landfills having a gas-producing waste pile, including a lower geocomposite positioned over the gas-producing waste pile, a protective layer of soil is positioned over the lower geocomposite. An upper geocomposite is positioned over the protective layer of soil such that the protective layer of soil is positioned between the lower and upper geocomposites. An impermeable geomembrane is positioned over the upper geocomposite. A cruciform gas collector conduit grid is positioned within or atop the protective layer of soil and has a plurality of collection orifices formed adjacent the vertical openings formed in the protective layer of soil. The impermeable geomembrane is non-perforated adjacent the collection orifices and the cruciform gas collector conduit grid is adapted for delivering collected gas laterally from beneath the geomembrane rather than vertically through the geomembrane.

A gas vent for a landfill includes a sub-surface gas collection manifold for collecting sub-surface gas from beneath a geomembrane. Preferably, the collection manifold includes a plenum for receiving sub-surface gas. A conduit is connected to and extends upwardly from the plenum, with the conduit communicating with the interior volume of the plenum and having an upper discharge end. The conduit is adapted and provided for communicating sub-surface gas from within the interior volume of the plenum through the geomembrane. An activated charcoal filter disposed adjacent the discharge outlet of the hood removes odors from the gas as it is discharged from the discharge outlet.

Devices and techniques related to landfill gas extraction are disclosed. A technique for controlling extraction of landfill gas from a landfill through a gas extraction system is described. The method may include measuring a plurality of values indicating conditions associated with the landfill; computing, based at least in part on the plurality of values and on a model of the landfill, a predicted future state of the landfill; determining, based at least in part on the predicted future state of the landfill, one or more control parameters for one or more respective control devices configured to control operation of the gas extraction system; applying the one or more control parameters to the one or more respective control, and with the one or more control devices, controlling extraction of the landfill gas from the landfill based, at least in part, on the one or more respective control parameters.

Devices and techniques related to landfill gas extraction are disclosed. A technique for controlling extraction of landfill gas from a landfill through a gas extraction system is described. The method may include measuring a plurality of values indicating conditions associated with the landfill; computing, based at least in part on the plurality of values and on a model of the landfill, a predicted future state of the landfill; determining, based at least in part on the predicted future state of the landfill, one or more control parameters for one or more respective control devices configured to control operation of the gas extraction system; applying the one or more control parameters to the one or more respective control, and with the one or more control devices, controlling extraction of the landfill gas from the landfill based, at least in part, on the one or more respective control parameters.

A low-profile fluid collection conduit includes an elongate outer cover having an upper portion and a lower portion generally opposite the upper portion, with the outer cover being much wider than it is tall and defining an interior volume. An elongate rigid spacer is fitted within the interior volume of the elongate outer cover, with the elongate spacer allowing the majority of the interior volume to be unfilled so as to permit the flow of fluid along and within the elongate outer cover. The collection conduit is used with a fluid-impermeable membrane as part of a landfill fluid collection and conveyance system.

The invention provides a method for efficiently adjusting existing landfill gas well head control devices in a manner which reduces the overall air migration into the landfill's gas collection systems in a short period of time. The method also provides for mapping out hydrogen sulfide concentration areas of landfills; allowing for efficient evaluation and selective reduction of hydrogen sulfide.

A control system for controlling extraction of landfill gas from a landfill via a gas extraction system, the gas extraction system comprising well piping for coupling a plurality of wells to a gas output. The control system comprises a controller configured to: obtain a value indicating measured energy content of landfill gas collected at the gas output from the plurality of wells; determine whether the measured energy content is different from a target energy content; and in response to determining that the measured energy content is different from the target energy content: control a plurality of valves disposed in the well piping to change flow rates of landfill gas being extracted from at least some of the plurality of wells at least in part by changing degrees to which the plurality of valves are open.

Described herein are embodiments of a control system that automatically (1) determines whether a gas extraction system is in a state in which landfill gas is being released into the atmosphere, and (2) automatically controls landfill gas flow to mitigate, prevent and/or stop the release of landfill gas. The control system may control a valve to control flow of landfill gas through well piping of the gas extraction system. The pressure of landfill gas in the well piping at a location upstream of the valve may indicate whether there is a risk of landfill gas being released into the atmosphere. The control system may adjust a position of the valve in response to determining that the pressure at the location upstream of the valve indicates that there is a risk of landfill gas being released into the atmosphere.

Devices and techniques related to landfill gas extraction are disclosed. A technique for controlling extraction of landfill gas from a landfill through a gas extraction system is described. The method may include measuring a plurality of values indicating conditions associated with the landfill; computing, based at least in part on the plurality of values and on a model of the landfill, a predicted future state of the landfill; determining, based at least in part on the predicted future state of the landfill, one or more control parameters for one or more respective control devices configured to control operation of the gas extraction system; applying the one or more control parameters to the one or more respective control, and with the one or more control devices, controlling extraction of the landfill gas from the landfill based, at least in part, on the one or more respective control parameters.