Using Ambient Methane Concentrations to Estimate Total Landfill Emissions 

Background:

Although some modern landfills capture and use much of the methane gas produced, a non-negligible amount of methane is emitted to the atmosphere. Quantifying the amount of methane arising from landfills is a key point in GHG mitigation. In addition, measurements of methane emissions can allow the assessment of the efficiency of landfill gas recovery systems before and after improvement actions. An accurate measurement of methane emissions can also assess the efficacy  of any other mitigation technologies such as biocovers.

Measurement techniques for fugitive landfill methane emissions include: static and mobile plume measurement methods using tracer gas, radial plume mapping (RPM) using optical remote sensing (ORS) by means of laser infrared radiation emissions,  differential absorption light detection and ranging (LiDAR) and inverse plume modeling. 

Amongst all currently available methods, the tracer release based estimates of total emissions is considered to be the most accurate method, but it tends to be very expensive. We have the capacity to perform mobile and stationary tracer release testing and would like to use it to “ground-truth” other less expensive technologies. 

Objectives:

The primary objective of the proposal is to make a significant contribution in the efforts of converting ambient air methane concentrations monitoring, acquired via SEM, Drones, or even satellites, to estimates of methane emissions flux, in mass per time. The scope of the project consists of one-week field testing campaign:

•        Task 1 and Task 2: Perform controlled acetylene release experiments at Waste Management Inc. landfill and monitor acetylene and methane concentrations on the landfill surface to characterize plume dispersion at the micro-scale (under landfill conditions) and collect ambient air methane and acetylene concentrations measured via Surface emissions monitoring (SEM) campaigns, and (2) drone emissions monitoring (DEM) campaigns

•      Task 3: Use the collected data in Task 1 and 2 to calibrate the inverse plume modeling approach in identifying and locating hotspots approach and in estimating source strength in our methodology.

•       Task 4: Perform mobile and stationary Tracer correlation tests to obtain “most likely estimate” of true total emissions from the landfill during SEM, and DEM

•     Task 5: Use mobile tracer results to verify the methodology and develop approaches to determine independent estimates of total methane emissions from the landfill using SEM, and DEM.

•       Obtain USEPA, SWICS and CALMIN emissions estimates using the data from the site and compare them to measured emissions.