Tucson proposes landfill upgrade to avoid $300K fine

Tucson officials proposed late Friday upgrading the region’s major landfill to avoid a nearly $300,000 fine for allowing excessive methane emissions.

The excessive emissions at Los Reales Landfill were discovered more than a year ago but city and county officials are still grappling with what to do about it. Methane, a natural byproduct of the decomposition of garbage, is a very potent greenhouse gas whose emissions are directly linked to the continued increase in global temperatures.

People with sensitive lungs can suffer breathing problems from excessive methane exposure. Methane is also a flammable gas in high enough concentrations, but county officials say the methane concentrations at the city’s Los Reales Landfill, at 5300 E. Los Reales Road on the city’s southeast side, haven’t reached flammable levels.

Friday — their deadline to avoid an immediate fine — city officials gave county environmental regulators a plan to upgrade the landfill’s methane gas collection system, to try to avoid being fined by the Pima County Department of Environmental Quality.

The city proposes to spend a little more than the potential fine — $358,000 — to install four new wells to boost a methane gas collection system that county environmental officials say is now inadequate.

An April 2024 inspection of the landfill by PCDEQ and U.S. Environmental Protection Agency officials found significant violations of county emission limits for methane.

Since then, the county agency has formally informed the city Department of Environmental Services that the landfill is violating the emission limits, and the two agencies have spent considerable time discussing possible fixes.

City officials say they have made repairs at the landfill following the issuance of the violation notice to bring current emissions into compliance with county limits.

“The city understands the importance of preventing landfill gas emissions above regulatory limits and the air quality degradation caused by the emissions discovered on April 10, 2024,” Assistant City Manager Kristin Swallow wrote PCDEQ officials Friday, in submitting the city proposal.

“The city is committed to ensuring continued compliance with its permit requirements and further improving the existing gas collection and control system,” through its proposed upgrade, Swallow wrote.

County officials say the city needs to do more to upgrade the system to insure a rerun of the violations doesn’t occur. They say the new city proposal still isn’t acceptable but they will keep talking with city officials rather than fine them now.

Methane plume

The landfill isn’t adequately capturing “fugitive” emissions — emissions that have no common point source and form all over the landfill, PCDEQ officials say.

“The goal is to insure they are being captured and flared” harmlessly into the atmosphere, said Natalie Shepp, a PCDEQ spokeswoman.

Flaring converts the methane into a carbon dioxide-water compound. The CO2 is not nearly as potent a greenhouse gas as methane, although it survives longer in the atmosphere.

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Nationally, landfills are the third largest source of human-related methane emissions in the U.S., accounting for 14.4% of all methane emissions in 2022, the EPA says.

Los Reales, the only active landfill currently owned and run by the Tucson, accepts garbage delivered by city trash trucks as well as by private commercial haulers who collect trash from homes and businesses outside city limits.

Several air samples taken during the April 10, 2024 inspection exceeded the 500 parts per million methane limit, “with a few of them showing more than 1,000 parts per million, from several thousand to over 10,000” parts per million, Pima County Environmental Quality Director Scott DiBiase said in a recent interview.

A map of the landfill area from the time the violation occurred showed a giant blue blog encompassing the landfill site, illustrating the methane plume there. It was prepared by Carbon Mapper, a nonprofit group that uses satellite and other remotely sensed data to pinpoint high methane and CO2 concentration hotspots around the world.

Why it has taken so long

PCDEQ issued a formal notice last October that the landfill is violating its air quality permit from the county. The violation notice came six months after the site inspection because it took time on the technical side to coordinate a clear message to the city, DiBiase said.

EPA “is working on their own assessment in terms of compliance enforcement,” the county’s DiBase said. Asked about this, EPA replied through a spokesman, “EPA does not comment on any possible investigation or ongoing enforcement.”

The city Environmental Services Department pledged in November to upgrade its landfill methane collection system to prevent such violations from re-occurring. It also said it had taken other steps to prevent violations and that the landfill was now complying with the emission limits.

“The actions that inevitably led to this violation were largely due to a gap in knowledge for key City personnel,” City Environmental Services Administrator Frank Bonillas wrote the county environmental agency in November. He pointed to loss of employees due to people retiring or seeking other opportunities, combined with “hiring challenges since the pandemic in 2020.”

The city has addressed some issues to get adequately trained “boots on the ground” — people to conduct periodic assessments of the gas capture system, DiBiase said. But city officials haven’t addressed “fundamental issues with the gas capture system itself,” he said earlier this month.

Besides installing new gas extraction wells, the city says it will perform a comprehensive landfill gas wellfield assessment and repairs, if needed, of 42 existing gas extraction wells, Swallow wrote to the county.

Park envisioned at site

At some point, city officials would like to turn an area adjacent to the landfill into a 42-acre city park, complete with eight lit soccer, football, lacrosse and rugby fields. The city Parks and Recreation Department has started design work on a Los Reales Park and has said a master planning process will determine what other amenities the public desires there.

Parks on this scale typically also include a splash pad, sports courts, a dog park, a skate park, and/or walking paths, parks officials say.

But the city has only raised $3 million so far for the park development, when parks of that scale typically cost far more to develop. County environmental officials have expressed strong concerns about the park proposal because of the methane’s presence at the landfill.