Gas Measurement in Landfills

Landfill gas falls into five basic monitoring categories: soil gas, near surface gas, emissions, ambient air, and facility air. Surface and ambient air monitoring are accomplished by grab samples or portable organic vapor analyzer‐flame ionization detectors. Soil gas, emissions, and facility air are environments suited for thermal mass flow devices.

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Landfill Gas Metering Applications

Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Collection Port
The combined off-gas is measured for methane content, filtered and collected as fuel to be used in energy production (cogeneration).

Gas Characteristics:
Varying, Condensing
Flare Gas
Excess landfill gas not used in power production (cogeneration) is sent to the flare. Precise monitoring of gas constituents and volume is crucial to meet emissions requirements.

Gas Characteristics:
Condensing
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow
Off-Gas Vents
Biogas seeps up from landfill cells and is collected in recovery wells. The gas composition varies widely based on time of day, rainfall and material being biodegraded. Moisture condenses from the gas and collects on pipe walls and meter sensors.

Gas Characteristics:
Varying Composition, Condensing, Low Flow

Landfill Gas Metering Instruments

Condensing Gas

Landfill decomposition gases have low flow rate and high moisture content. The amount of moisture can be affected by the decomposition process, the ambient temperature and rain soaking into the ground. All the gas is collected and filtered to separate the methane and moisture condensation is a perpetual factor. The amount of moisture condensation is unpredictable and varies day to day. Condensing gas in landfills is low flow, may contain hydrogen sulfide and other compounds

Flare Gas

Gases from buried waste matter seep into collection pipes at varying rates. Excess biogas collected from the landfill that cannot be stored or used in power production (cogeneration) is sent to the flare tip to be burned. Flaring is minimized because biogas is valuable and because it is a dangerous greenhouse emission. The biogas flow rate is extremely low and its moisture level is high.