Reducing Methane Emissions from Landfills: The Potential of Biocover Systems

Published

2026

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Landfills are responsible for approximately 11% of anthropogenic methane emissions and consequently a significant source of anthropogenic methane. This contribution to greenhouses gases (GHG) is rising, mainly due to increasing amounts of waste that accumulate on managed and unmanaged sites in large parts of the world, which emit methane decades after disposal. However, this trend can be reversed. Measures to reduce landfill methane emissions include landfill gas capture and treatment and biocovers. They come with additional health and air quality benefits. Well-designed methane oxidation covers not only reduce methane emissions but can also reduce odour and the emission of Volatile Organic Compounds (VOCs) and other toxic substances.

The report addresses the emerging technology of one bio-mitigation system which is of increasing interest for policymakers, researchers and investors in dealing with landfill-based emissions.

It addresses:

How suitability of biocovers in different contexts can be assessed
What complementary actions need to be taken, including from policymakers
What the methane reduction impact could be
What the costs are and how biocovers can be effectively designed, financed, constructed and maintained.

This document intends to demonstrate options for mitigation actions that can be done in most country contexts, and how to maximize impact with limited means.

Landfills are a major and long-term source of methane emissions.

Landfills contribute approximately 11% of global anthropogenic methane emissions, and methane production continues for decades after waste disposal ends. The report’s methane generation curve shows emissions rising during landfill operation, peaking around closure, and then slowly declining over many decades. This matters because landfill methane is both a major climate driver and a persistent emissions source, meaning mitigation solutions must function long after landfill closure to have meaningful climate impact.

Biocovers can significantly reduce methane emissions, especially at unmanaged landfills.

Biocovers use naturally occurring bacteria to oxidize methane into less harmful carbon dioxide and water. The report shows that biocovers can reduce methane emissions by nearly 50% at unmanaged landfills and provide meaningful reductions even at managed sites. This matters because unmanaged dumpsites are widespread globally, and biocovers offer a practical, scalable solution where more complex gas capture infrastructure is not feasible.

Biocovers are most effective when methane generation rates are relatively low.

The report’s modeled methane generation graphs demonstrate that unmanaged or shallow landfills produce methane at lower rates that fall within the oxidation capacity of biocovers. This makes biocovers particularly suitable for older, closed, or unmanaged landfills where methane generation is moderate rather than extreme. This matters because it shows biocovers can be targeted strategically to sites where they deliver the greatest emissions reductions relative to cost.

Biocovers are a relatively low-cost methane mitigation option.

Biocover construction and operation costs are relatively modest compared to other methane mitigation technologies, with construction typically costing $50,000 to $250,000 per hectare and mitigation costs ranging from $5 to $15 per tonne of CO₂-equivalent. This matters because cost-effective mitigation technologies are essential for widespread adoption, especially in developing countries where financial and technical resources may be limited.

Proper design and layering are essential for biocovers to function effectively.

Biocovers consist of multiple engineered layers—including gas distribution, methane oxidation, and topsoil layers—that work together to ensure methane flows evenly and is fully oxidized. The diagram illustrates how gas moves upward through the system and is converted by microbial activity. This matters because poor design or maintenance can significantly reduce effectiveness, meaning engineering quality is critical to achieving real methane reductions.