Landfill Methane Flow (Scholl Canyon)
Computes the methane flow generated by one batch of landfilled waste using the Scholl Canyon first-order decay model, Q = k × L₀ × M × e^(−k×t), where M is the mass of that batch, L₀ is the total methane potential per tonne, k is the annual decay constant and t is the age of the batch. The model assumes generation peaks right after placement and falls exponentially from then on, with k between 0.04 and 0.09 per year in wet climates and L₀ typically 50 to 170 m³ of methane per tonne of wet waste, 170 being the LandGEM default. Since the model is linear in mass, a real landfill is summed batch by batch, each with its own age. Enter the decay constant, the methane potential, the waste mass and the age of the batch.
Result
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Landfill Methane Flow with the Scholl Canyon Model
Before deciding whether a landfill can carry a gas engine, a high-temperature flare or just a passive burner, somebody has to estimate how much methane that buried mass still produces each year. The same figure feeds greenhouse gas inventories, carbon credit projects and the sizing of blowers and extraction wells. The Scholl Canyon model is the de facto standard for that estimate, used by LandGEM and by inventory methodologies, precisely because it needs only two fitted constants.
The flow is Q = k × L₀ × M × e^(−k×t): the peak happens right after placement and equals k × L₀ × M, decaying exponentially with the age of the batch. With the default values — k of 0.05 per year, L₀ of 100 m³ of methane per tonne, 500 thousand tonnes and an age of 5 years — the peak would be 2,500,000 m³ per year and the five-year figure is 1,947,002 m³ per year, roughly 222 m³ of methane per hour, or close to 2.2 MW of thermal input in an engine. One check outside the point formula: integrating the flow over all time gives exactly L₀ × M, here 50 million m³, whatever k may be.
The result is generation, not capture. What reaches the flare passes through the efficiency of the extraction system, typically 50 to 90 percent, and part of what escapes still gets oxidised in the cover layer. The model assumes an instant peak in year zero, ignoring the aerobic phase and the lag until methanogenesis settles, so it overstates the early years. Composition, moisture, climate and cover design all hide inside k and L₀: moving k from 0.04 to 0.09 shifts the five-year flow by 75 percent, and published L₀ values span a factor of three. The page computes one batch at a time, with no landfill-wide summation and no stored results.
Frequently asked questions
How do I estimate a whole landfill instead of one batch?
Which values of k and L₀ should I adopt?
Is the calculated flow what the engine will receive?
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.