Solid waste teams are being asked to quantify methane emissions more accurately while improving operational efficiency and community transparency. Yet traditional tools only show part of the picture. To explore better options, the Environmental Research and Education Foundation (EREF) conducted a field study comparing current methane monitoring practices against measurement-based technologies developed by Bridger Photonics, including Gas Mapping LiDAR® (GML) and Flux Curtain.
The goal: understand whether these modern approaches can give operators more accurate insights into emissions across the entire landfill as well as whole-site emissions totals.
Rethinking How We Measure Landfill Methane
Methane remains a core operational challenge for landfills: it drives compliance obligations from state and federal regulations, and affects community perception. Yet, today’s standard tools for quantifying emissions have limitations, miss individual leaks, and often overestimate modeled annual whole-landfill emissions estimates, leading to incorrect placement in regulatory tiers and adding unnecessary costs.
Most operations still rely on:
- EPA Method 21 surface emission monitoring (SEM) — effective at detecting small leaks, but slow, labor-intensive, and limited to paths walked and risk missing significant leaks
- Whole-landfill estimates using the tracer correlation method (TCM) — highly sensitive to assumptions that rarely reflect real-world landfill variability
As a result, operators often lack a full picture of where emissions are occurring and how actual performance compares to modeled expectations. This EREF study took place at the Yolo County Landfill in Davis, California to compare these traditional methods with:
- Bridger’s GML technologyAerial methane detection with complete spatial coverage, quantified emission rates, pinpointed emission sources, and geolocated plume imagery
- Bridger’s Flux Curtain technologyA drone-based approach for measuring whole-landfill emissions, measured on the downwind side of the facility
A blind controlled methane release at a nearby wastewater facility provided a key accuracy check.
Landfill Emissions Detection Results Using Bridger’s Technology
High-Resolution Emission Mapping Using GML
One of the clearest results of the study was the difference in coverage and emissions detection between traditional SEM using Method 21 and GML.
While Method 21 crews walked one section of the landfill over the course of several mornings, GML scanned the entire 900-acre facility in under an hour per pass. Instead of Method 21’s 100-foot grid line spacing, the LiDAR system provided a spatially continuous aerial view of methane concentrations, revealing plume shapes, sizes, and origins that are impossible to discern from ground-based measurements alone.
Researchers found agreement where both methods detected the same emissions, but also many cases where GML identified localized emission hotspots that were missed between Method 21 grid lines. The visual clarity of the LiDAR data made it easy to trace these plumes back to precise source points, whether from seeps, digesters, or equipment.
Accurate Whole-Landfill Measurement Using Flux Curtain
The study also evaluated Bridger’s Flux Curtain method, which uses LiDAR to measure methane concentrations and wind speeds along a vertical plane downwind of the site. By scanning this plane repeatedly, researchers were able to calculate a whole-landfill emission rate grounded in actual, observed plume behavior.
Flux Curtain produced consistent estimates across measurement locations, reflecting the method’s ability to capture the vertical structure of methane plumes—something traditional models cannot do. The Flux Curtain total emissions measurement differed significantly from TCM (Flux Curtain measurement indicated less total emissions than TCM), and demonstrated a strong, defensible capability for quantifying total site emissions.
Controlled Release Validation
To independently validate the detection method, the research team conducted a blind controlled methane release at a nearby wastewater treatment plant. The true release rate was unknown to the measurement team during testing.
Flux Curtain estimated the release within ~10% of the actual value, confirming its quantitative accuracy.
What Does This Mean for Landfill Operators?
Taken together, the findings from EREF’s Yolo County Landfill study point to a meaningful shift in how landfill operators can manage methane. For the first time, they have access to a technology that delivers both high-resolution surface mapping for individual leaks, and defensible full-facility measurement, all in a format that operators can interpret quickly.
This matters because operators are being asked to do more with their methane data: Demonstrate compliance, justify operational decisions, respond to community concerns, and prepare for more measurement-driven regulations. Traditional tools give only partial visibility into what’s happening across the site.
GML provides a complete, map-based picture of surface emission sources and plume locations, helping teams pinpoint exactly where methane is escaping, and how large the individual emissions are.
At the same time, Flux Curtain offers a path toward true whole-landfill quantification. For operators facing model-based overestimates and resulting inflated regulatory tiers and costs, having a defensible, measurement-based emissions rate for an entire facility can meaningfully influence planning, budgeting, and compliance.
In short, the study demonstrates that landfill methane management no longer has to rely solely on assumptions, sparse transects, or outdated monitoring practices. With modern tools like GML and Flux Curtain, operators gain the ability to see the full landscape of emissions, understand how methane moves across their site, and make decisions grounded in real, observable data.
Learn More About Landfill Emissions Mapping and Measurement
The Yolo County Landfill study makes it clear that measurement-based methane monitoring is not only possible for landfills but practical, scalable, and ready for real-world operations.
If you want to explore the findings yourself, the full EREF-funded report is available to read online and offers a deep technical look at how each method performed under actual field conditions.
For landfill teams evaluating new approaches to methane detection, our Gas Mapping LiDAR for Landfills solution brings the same capabilities validated in the study and widely adopted across the global oil and gas value chain to landfills.
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