Devices and techniques relating to landfill gas extraction

A 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 system comprising:

• at least one multi-well controller configured to:
• perform a global control method comprising:
• obtaining, at the gas output, a measure of a concentration of nitrogen in landfill gas collected from at least some of the plurality of wells, the at least some of the plurality of wells including a first well;
• determining, for one or more wells of the at least some of the plurality of wells, using the concentration of nitrogen in the landfill gas collected from the at least some of the plurality of wells and a first measure of concentration of at least one constituent gas in landfill gas collected from the first well, whether to adjust respective flow rates of landfill gas being extracted from the one or more wells, the one or more wells including the first well;
• and
• when it is determined to adjust the flow rate of landfill gas being extracted from the first well, adjusting the flow rate of the first well;
• and
• at least one first single well controller configured to:
• perform a local control method comprising:
• obtaining, at the first well, a second measure of a concentration of at least one second constituent gas in landfill gas collected from the first well;
• determining, using the second measure of the concentration of the at least one second constituent gas in the landfill gas collected from the first well, whether to adjust the flow rate of the first well;
• and
• when it is determined to adjust the flow rate of the first well, adjusting the flow rate of the first well.

At least one non-transitory computer-readable medium having instructions encoded thereon, that, when executed by at least one controller, cause the at least one controller to perform a method 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 method comprising:

• performing, using a multi-well controller, a global control method comprising:
• obtaining, at the gas output, a measure of a concentration of nitrogen in landfill gas collected from at least some of the plurality of wells, the at least some of the plurality of wells including a first well;
• determining, for one or more wells of the at least some of the plurality of wells, using the measure of concentration of nitrogen in the landfill gas collected from the at least some of the plurality of wells and a first measure of concentration of at least one constituent gas in landfill gas collected from the first well, whether to adjust respective flow rates of landfill gas being extracted from the one or more wells, the one or more wells including the first well;
• and
• when it is determined to adjust the flow rate of landfill gas being extracted from the first well, adjusting the flow rate of the first well;
• and
• performing, using at least one first single well controller, a local control method comprising:
• obtaining, at the first well, a second measure of a concentration of at least one second constituent gas in landfill gas collected from the first well;
• determining, using the second measure of the concentration of the at least one second constituent gas in the landfill gas collected from the first well, whether to adjust the flow rate of the first well;
• and
• when it is determined to adjust the flow rate of the first well, adjusting the flow rate of the first well.