Colorado launches first-of-a-kind landfill-methane monitoring program

Landfills are the third-largest source of methane, a super-pollutant greenhouse gas that traps 80 times more heat than carbon dioxide over a 20-year period. While the U.S. Environmental Protection Agency places caps on methane and other emissions from landfills, experts say that monitoring and enforcement is largely on an honor system. An analysis published earlier this year found that 95 percent of landfills across eight states had at least one violation of EPA safe limits.

Colorado is aiming to change that. State officials are launching a large-scale initiative to reduce greenhouse gas emissions that includes plans to implement cutting-edge technologies for monitoring methane emissions from the state’s 80 landfills. The program, funded by a $129 million Climate Pollution Reduction Grant from the EPA, is the first of its kind and could set a precedent for other states, said Suzanne Jones, the executive director of Eco-Cycle, a Colorado-based nonprofit that promotes the development of zero-waste communities.

“Methane is an incredibly potent greenhouse gas. If we can address releases of methane, we can buy ourselves some time in the race to get climate impacts under control,” Jones said. ​“First, it’s important to have the data so that you can do something about it.”

To limit methane emissions from landfills, operators around the country are required to maintain extraction systems that collect and burn gases produced by decomposing trash. Tarps covering the landfill trap methane, while networks of pipes transport the gas to flares. Soil and plant cover can further prevent methane from leaking. But over time, tarps degrade and pipes crack, causing methane to seep out across the landfill’s face or billow out in plumes. Ideally, emissions monitoring allows landfill operators to identify and address problems with the way waste is handled. In reality, however, the most common monitoring practices provide only a patchwork picture of methane emissions.

In the United States, landfill operators must perform quarterly ​“walking” surveys, in which they or a third party use a handheld analyzer to measure methane concentrations at various sites across a landfill, said Daniel Cusworth, a data scientist at Carbon Mapper, a nonprofit that uses remote sensing to visualize methane emissions. These surveys — in addition to being infrequent and often self-reported — don’t typically cover the whole landfill. ​“Landfills are complex and dangerous to walk,” Cusworth wrote in an email. For example, the area where trash is actively being dumped, called ​“the working face,” usually doesn’t get checked because of safety issues — but it’s also a large source of a landfill’s methane emissions. Additionally, walking surveys detect only whether a particular point on a landfill exceeds EPA requirements at any given moment — they don’t actually do real emissions monitoring, which would reveal just how much methane is leaking out over time, Cusworth said.

Newer technologies — like drones, aircraft, and satellites equipped with methane-detecting components — make it possible to spot leaks and quantify their true scale. These technologies can provide data at an incredibly high resolution, ​“on the scale of meters to tens of meters,” Cusworth said. That allows the state and operators to quickly respond to the root cause of methane leaks and seepage.

Colorado has been using these instruments for years to spot leaks from oil and gas infrastructure. This track record puts it in a unique position to lead the way on landfill methane monitoring, Eco-Cycle’s Jones said. ​“Colorado is at the forefront of methane monitoring when it comes to oil and gas development,” Jones said. ​“The same technologies could and should be used to monitor landfills.”

Some organizations are already doing this. Carbon Mapper, for instance, conducts flyovers in planes equipped with special cameras that can detect methane plumes from landfills. When it identifies super-emitting events — plumes emitting more than 100 kilograms of methane per hour — the organization notifies state agencies and landfill operators. Carbon Mapper has found that nearly half the time, these giant plumes had gone completely undiscovered prior to its survey.

But when it comes to landfill monitoring, these technologies ​“have not traditionally been used in regulatory environments,” Cusworth said. In other words, they’ve mostly been used on a voluntary basis. Colorado’s new initiative includes funding to start deploying them as a regulatory tool.

Exactly what technologies the state will make use of hasn’t yet been decided. A technical working group needs to hammer out those details in a six-session rulemaking process that wraps up in December. However, this working group ​“has an eye towards more robust drone- and satellite-monitoring technologies,” Jones said. ​“That would put Colorado on the map as a leader.”

While other states, including Maryland, Washington, Oregon, and California, have developed their own emissions standards that are stricter than national requirements, all use manual monitoring. That allows super-emitting landfills to fall through the regulatory cracks. ​“We are hoping that the Colorado Department of Public Health and Environment will be proposing a strong draft rule that will include nation-leading requirements around monitoring and leak detection using satellites,” Jones said.