Food Waste Landfill Methane Calculator

What This Calculator Estimates

Food waste decomposes anaerobically in landfills and can generate methane. This calculator estimates the potential methane from one year of landfilled food waste, then subtracts methane recovery and cover oxidation to estimate emitted methane. It is best used for education, rough planning, and comparing diversion scenarios.

The timeline bars use a simple first-order decay curve to show timing. Formal greenhouse gas inventories usually model many years of waste deposits rather than only the lifetime potential of one annual deposit.

Assumptions and Sources

• The food-waste DOC default is 15% of wet weight, matching the IPCC default for food waste in municipal solid waste.
• The DOCf default is 0.5, the IPCC default fraction of degradable organic carbon that ultimately decomposes under anaerobic landfill conditions.
• Landfill MCF presets follow IPCC solid waste disposal site classes: 1.0 managed anaerobic, 0.5 semi-aerobic, 0.8 unmanaged deep, 0.4 unmanaged shallow, and 0.6 uncategorized.
• The methane fraction default is 0.5, the IPCC default for generated landfill gas.
• The oxidation default is 10% for a covered, well-managed landfill. Set it to 0% where cover oxidation is unknown or unsupported.
• The GWP100 default is 28; EPA describes current IPCC AR6 methane GWP100 values as a 27-30 range and notes that GWP20 values are much larger.

References: IPCC 2006 Guidelines Volume 5, Chapter 2, IPCC 2006 Guidelines Volume 5, Chapter 3, and EPA Understanding Global Warming Potentials.

Limit: this is not a regulatory inventory, landfill design model, or climate claim. Document local data before using results in formal reports.

FAQs

How much methane does food waste make in a landfill?

It depends on the amount of food waste, degradable organic carbon, landfill management, methane capture, cover oxidation, moisture, and decay rate. The calculator makes each of those assumptions visible and editable.

Why does the calculator show current and target landfill shares?

That comparison estimates how much methane could be avoided if less food waste goes to landfill. It does not assign emissions to composting, anaerobic digestion, animal feed, or prevention pathways.

Why is recovered methane subtracted before oxidation?

IPCC guidance applies oxidation after methane recovery, because only unrecovered methane can pass through landfill cover where oxidation may occur.

Should I use GWP20 or GWP100?

GWP100 is commonly used in greenhouse gas inventories. GWP20 emphasizes methane's nearer-term warming effect. You can change the GWP input if your project uses a different horizon.

Does the calculator include biogenic CO2 from food waste?

No. It focuses on methane. IPCC waste guidance generally treats carbon dioxide from biomass-derived waste as biogenic, while methane is counted because it has a stronger warming effect.