Tres Rios Renewable Gas Center Celebrates One Year Anniversary and Contributions to Reaching Pima County Emissions Goals

Category: Arizona
October 24, 2022
TUCSON, Ariz. – The Pima County Regional Wastewater Reclamation Department (RWRD) and Southwest Gas Corporation (Southwest Gas) are marking the one-year anniversary of the opening of the Tres Rios Renewable Gas Center (Tres Rios) biogas cleaning facility.
Located at the Tres Rios Water Reclamation Facility (WRF), this innovative facility was the first of its kind in Arizona connected to the gas pipeline to deliver clean-burning renewable natural gas (RNG) made from biogas to homes and businesses throughout the Pima County community. This partnership advanced innovative solutions to reduce emissions and produce a cleaner-burning fuel.
In terms of greenhouse gas emissions, Tres Rios’ impact is equivalent to removing 2,500 vehicles from the road or generating energy for 5,500 homes, thus both bringing significant benefits to the environment and complementing Pima County’s ongoing efforts to preserve unique desert environments and reach carbon reduction emissions goals by 2030.
The Tres Rios facility was connected on Oct. 21, 2021 and has been sending 550-600 standard cubic feet per minute (SCFM), or 440 MMBtu/day, of renewable natural gas (RNG) into the Southwest Gas pipeline. Since the facility opened, Southwest Gas has purchased nearly 100,000 dekatherms of RNG from Pima County.
Previously, the biogas—a byproduct of the secondary wastewater treatment process—would have been flared off into the atmosphere. The refinery now recovers up to 99.5 percent of the methane; the process removes impurities, moisture and carbon dioxide, leaving a clean burning, low-carbon fuel that is estimated to emit 95 percent less carbon emissions than processes that produce diesel and gasoline.
“RNG is a powerful solution for a balanced energy future that is part of a suite of sustainable energy sources that are helping to transform how we fuel lives, homes and businesses while honoring our commitment to environmental stewardship for long-term change,” said Dr. Laura S. Nelson, vice president of sustainability and public policy at Southwest Gas.
Tres Rios WRF serves the metropolitan Tucson area and is the centralized biosolids treatment location for all of Pima County’s eight water reclamation facilities. Operating 24 hours a day, 365 days a year, the facility treats approximately 50 million gallons of wastewater daily.
“Southwest Gas is committed to employing sustainable technologies to assist our communities in achieving their environmental and climate goals. This project is an example of this commitment to partnering with our communities on projects that enhance the quality of life in our service territories,” Nelson said.
Tres Rios is now just one of four Southwest Gas RNG partnership facilities in operation throughout Arizona.

Media Contact – Southwest Gas:
Sean Corbett, Manager Corporate Communications