Many landfills are still using hand-held monitoring of methane “hot spots” for compliance purposes while relying on models to estimate LFG emissions. Although technological developments in optical remote sensing and other methods offer significant improvements to measuring actual surface emissions from landfills, no single technology or method has risen to the top of the scientific hierarchy, gained universal acceptance, and achieved regulatory approval. Clearly, the technological advances provide more comprehensive methods for measuring methane concentration, identifying methane hot spots and leaks, and providing better coverage of the entire landfill surface. However, some technology falls short in their ability to provide accurate, consistent, and repeatable methane flux or emissions measurements.
As monitoring technology evolves, so have the various ways SCS takes measurements, from source level, drones, and high-altitude aircraft, to satellites. This paper presented at A&WMA by Patrick Sullivan and Raymond Huff summarises and provides details on the following methods:
• First order decay (FOD) modeling for landfills without active LFG collection systems.
• Non-FOD modeling for landfills without active LFG collection systems.
• FOD modeling with measured LFG collection.
• Non-FOD models with various site-specific data input.
• Measured LFG collection with estimated collection efficiency.
• Surface emission monitoring for compliance purposes.
• Ground-based or low-altitude imaging for concentration or hot spot measurement.
• Satellite and aerial imaging for concentration or hot spot measurement.
• Flux chamber testing.
• Ground-level plume measurement.
• Stationary path measurement.
• Reverse air dispersion modeling.
• Tracer studies.
• Low or high-altitude imaging.
• Hybrid methods.