Montrose’s $33.6 million wastewater treatment plant expansion is moving forward, with major concrete work completed on a new anaerobic basin and installation underway on an upgraded UV disinfection system.
Construction is moving forward on the City of Montrose’s $33.6 million Wastewater Treatment Plant expansion, with major concrete work on a key treatment basin nearing completion.
Utilities Director David Bries updated City Council on the multi-year project during the June 2 council meeting, outlining recent progress on the facility’s new anaerobic basin, ultraviolet disinfection system, and related infrastructure upgrades.
The project is designed to modernize aging equipment, improve treatment performance, and prepare the plant for future nutrient regulations under Colorado Regulation 85.
According to Bries, the city has spent approximately $6.26 million so far, or about 18 percent of the total project budget.
Construction began after a March 16 groundbreaking ceremony, with excavation work starting almost immediately afterward.
One of the largest early milestones has been construction of the new anaerobic basin, a critical part of the plant’s upgraded nutrient removal process.
“Major progress was made on that,” Bries told council members.
Crews poured the final section of concrete for the basin floor on May 27. In total, the basin floor required more than 1,000 cubic yards of concrete.
Work has now shifted to building the basin walls. Crews are installing reinforcing steel for walls that will stand 17 feet tall and measure 18 inches thick.
“It will take several weeks to complete that process,” Bries said.
Additional upgrades are also moving forward elsewhere at the facility.
Crews are installing a new ultraviolet, or UV, disinfection system. Once testing and final inspections are complete, the upgraded equipment will be brought online.
The new self-cleaning UV system is one of several improvements planned as part of the expansion. The project also includes replacement of aging pumps and aeration equipment, upgrades to sludge handling systems, and construction of the new anaerobic basin to improve phosphorus removal.
Bries also told council members about a power outage that affected the treatment plant over Memorial Day weekend.
Electrical service was restored within a few hours using temporary above-ground power lines. Permanent replacement power lines are expected to be installed later this year.
“This reinforces the aging infrastructure needs that we have at the wastewater treatment plant,” Bries said.
The facility was originally commissioned in 1984 and underwent a major expansion in 2009, increasing its treatment capacity to 4.32 million gallons per day.
While the plant remains within its permitted capacity, city officials have said the current expansion is needed because of aging infrastructure, future growth, and anticipated regulatory requirements tied to nutrient removal.
At the March groundbreaking ceremony, Bries said the project is an important investment in a system that operates largely out of public view but plays a critical role in public health and community growth.
“For more than four decades, the City of Montrose’s Wastewater Treatment Plant has operated continuously, protecting public health and supporting the community’s growth,” Bries said. “These improvements represent an important investment in maintaining the reliability and performance of this essential system.”
The city is delivering the expansion through a progressive design-build partnership with Burns & McDonnell and Moltz Construction. That approach is intended to improve coordination between design and construction teams and streamline delivery of the complex infrastructure project.
Design work began in January 2025. Construction is expected to continue through fall 2027.
City officials said additional updates will be provided as work progresses. More information is available through the city’s Wastewater Treatment Plant Improvement Project webpage.
