The active face of landfills emit unchecked methane
Methane, a potent greenhouse gas, is emitting from the active face of landfills…and there’s no federal air emissions regulation in place to stop it.
Landfills produce methane emissions, as organic waste decomposes under anaerobic conditions. Under the Clean Air Act, since 1996 the EPA has overseen federal emissions requirements for certain large landfills that are aimed at reducing emissions. But a gap in current EPA emissions regulations is in addressing the active or working face of the landfill: the area where new waste is deposited. That gap in regulations means:
There is no required monitoring for methane emissions in the active or working face. This made sense years ago, as the EPA’s sanctioned method of a person walking on a landfill with a detection device in hand would be impractical and dangerous in an active area, with heavy equipment and unstable trash heaps to navigate. But today there are other available technologies like drones that the EPA could look at incorporating into their monitoring framework.
Gas control and capture systems, which would minimize emissions by capturing methane, are not required for the active face area. Federal regulations exempt it.
There are no federal air emissions regulations that dictate the type or timing of daily, intermediate or final cover. There is a separate federal regulation that provides standards for cover—the Resource Conservation and Recovery Act—but that’s aimed at debris and odor management, not practices that reduce methane emissions.
The active face is a blind spot for EPA methane emissions regulation. But just because the EPA doesn’t measure it, doesn’t mean the methane doesn’t exist. Thanks to modern technology, namely remote sensing, we can better understand where the emissions are coming from in a landfill area. Using Next Generation Airborne Visible/Infrared Imaging Spectrometer, (AVIRIS-NG) the California Methane Survey did overflights over 270 landfills and 166 organic waste facilities repeatedly over the time period of 2016 to 2018. Below is an example of methane plumes from the active face of the Potrero Hills landfill where they estimated active face emissions comprised 11%–21% of this landfill’s emission during the study period. Emissions from the active face are actually not that surprising when you remember that gas collection isn’t required and the cover on an active face is not as good as the final cover (see my previous post, The Type of Landfill Cover Matters).
Source: Using remote sensing to detect, validate and quantify methane emissions from California solid waste operations, Environmental Research Letters, April 29, 2020.
