SIMULATION FACILITY FOR LANDFILL EMISSION EXPERIMENTS (SIMFLEX)
For our upcoming controlled release study due for the end of September 2024, we invite you to click here.
National snapshot survey to see how much Canadian landfills emit
Canada wishes to regulate landfill emissions, and to guide the sector towards a 50% reduction in methane emissions by 2030. We lack validation data on current emissions levels, and need reliable data so we can make the right decisions. And since regulations won’t take effect until 2025, there is increased pressure to get the regulations right the first time.
So, in 2022 we conducted a field measurement study funded by Environment and Climate Change Canada, and the United Nations Environment Program International Methane Emissions Observatory, that took us to landfills from Vancouver Island to Newfoundland. In all we made nearly 150 landfill measurements, about three quarters of which were successful. We are still identifying root causes – What are the methane sources and how do they change over time?
We next undertook a major field study of landfills to understand sources and variability. Working at 12 landfills, in 3 different climate zones, we used trucks, tripods, and drones, onsite and offsite, to determine what was emitting and how much. We measured each site daily for a week and repeated the measurements in different seasons.
Our study revealed that active faces of landfills, where new waste is added, emit significant amounts of methane, and more than is accounted for in most models. We also observed considerable variability in source emissions over time, with higher rates in colder seasons and lower rates in summer, highlighting the need for continuous measurements to accurately estimate total emissions and further research to unravel the complexities of landfill methane dynamics. Our study helps point toward the active face as an area for mitigation. Technologies are available and new ones could be developed, but they aren’t yet being pursued in Canada.
Papers under development!
How can we improve the models used for the Canadian inventory?
To estimate landfill emissions Canada uses a model originally developed by the UN. Landfill models are developed for the average case and may substantially over- or under-estimate at individual sites. Our model optimization study is establishing parameters that increase modelled coherence with measured values. The study involves a super-computer and a huge number of model runs using different initialization values to see which combinations produce model results that fit consistently with measurements. We’ve found some interesting patterns thus far. Stay tuned! A huge thanks to Natural Resources Canada for supporting this project.
Papers under development!
Controlled release testing of measurement technologies
There is a variety of technologies that landfill operators can use to find leaks and measure leakage rates. But few of them are well validated.
In November 2023 we hosted the landfill measurement methane Olympics (unofficially).
Commissioned by the North American waste industry via the Environmental Research and Education Foundation, we built an experiment in which we invited vendors to come and see if they could blindly measure methane that we were emitting – on purpose. We had 10 computer-controlled release points situated on a closed WM landfill in southern Ontario, from which we were releasing methane at rates occasionally as high as 300 kg/hr. The release points were distributed over 30 acres. Many of the truck, drone, satellite, aircraft, and continuous emission measurement technologies performed well, although there were a few surprises. Look for the preprint soon!
We’re preparing follow-up studies! Watch for the announcement for the upcoming fall 2024 redux!
Can hyperspectral cameras detect area-source emissions?
Hyperspectral imagers are now commonly used on aircraft and satellites to detect methane. Mostly their application has been in oil and gas, where emissions come from pipes and small orifices. In these situations, the imagers can readily see the concentrated methane. But what happens when we disperse the emission, and spread it out over a much larger space – even acres? Hyperspectral imagers struggle to resolve the plumes and quantification algorithms may not work correctly.
In solid waste, agriculture, and natural environments, many methane sources are areal in nature. So, we have some work to do. We’re collaborating with researchers at the University of Waterloo on an NSERC Alliance Missions project to understand how we can better use a Telops hyperspectral camera system, from tripod and aircraft, to better measure area-source emissions.
Papers under development!
Drone TDLAS column sensors study
Walking is the normal way leaks at landfill sites are found. But a landfill might be 20 to 30 km on foot, with repeated up and downs, across uneven ground that can twist ankles, and can’t include active areas, which are methane hot spots. Drone surveys using TDLAS column sensors promise to replace walking surveys, but the overall methodology performed less well than we expected in our FluxLab-EREF controlled release study. So, we’re working with several organizations including Environment and Climate Change Canada, the US Environmental Protection Agency, Republic Services, and various manufacturers and vendors, to focus on application development of the technology.
No one previously did applications development work, and the sensors went straight from the shelf into commercial field environments using “best guess” work practices. We’re using sensors in real landfill settings, and in parallel highly controlled tests on the StFX campus, to understand work practice issues. Our goal is to help the technology make a good showing at the upcoming 2024 controlled release study in southern Ontario. We’re excited about the potential of these sensors.
Papers under development!
Landfill CFD modelling
With large hills and bumps on the landscape, air moves around landfills in interesting ways. Winds at the top can sometimes be several times higher than the base level, and at other times they might be similar. Winds can even circulate in different directions on each side of the landfill, with eddy currents creating complex flow, carrying emissions downwind in unexpected ways. These factors all create challenges for effective measurement. We are conducting CFD modelling of the southern Ontario controlled release site in hopes of better understanding air flows at the site, and why some measurement technologies perform better than others.
Papers under development!
