Wastewater Projects

These projects include sewer main replacements and other sewer system infrastructure projects to repair old, failing sewer mains or to increase the wastewater system’s capacity. Also included are projects at the Resource Recovery Facility and at Garden City Compost.

We will provide regular updates here and on Facebook as schedules are finalized or change. For more information, email Andy Schultz, City Engineer for Utilities, at SchultzA@ci.missoula.mt.us or call (406) 552-6758.

Resource Recovery Facility Solar Project—Completed

UPDATE—April 20, 2023:  Mayor Jordan Hess "flipped the switch" to celebrate completion of the solar array, which will provide 20 percent of the power needed to operate the City's wastewater treatment plant. 

Description:  As the City of Missoula moves toward its carbon emissions goals of net neutrality by 2025, the Public Works & Mobility Department has been working on a project for the last year that will result in the installation of 1,000 solar panels on the ground at the Resource Recovery Facility.

The solar array is expected to produce about 20% of the electricity needed to operate the wastewater treatment plant portion of the facility and offset about 700 metric tons of carbon dioxide, which is about 3% of the City’s overall emissions.

Pie chart of Municipal Emissions by Sector from the August 2021 report "City of Missoula Greenhouse Gas Emissions Municipal Inventory"The “City of Missoula Greenhouse Gas Emissions Municipal Inventory” report revealed that the City’s water and wastewater facilities account for 58% of the City’s overall emissions. As the Public Works & Mobility Department works to comply with City Council’s clean energy goals, staff considered the use of solar energy to reduce emissions.

Bozeman-based OnSite Energy conducted a feasibility study to determine what results could be achieved by installing solar at the Resource Recovery Facility. OnSite expects the panels will produce 650 kilowatt hours of power during the first year. Due to the array’s size and capacity, as well as other factors, the system will be non-export, meaning energy produced will be used exclusively at the plant and will not be made available for other electricity users.

The remaining 80% of annual power demands needed to operate the treatment plant will continue to come from NorthWestern Energy.

Benefit:  The solar array project helps reduce the City’s carbon emissions by producing solar power that will provide about 20% of the electricity needed to operate the wastewater treatment plant. This is a step toward achieving the Public Works & Mobility Department’s goal of reducing department emissions by 10% over the next five years.

Project Funding:  The City will pay for the project using a third-party funding model, which involves entering into an agreement with Ameresco to finance the project. Ameresco was selected through the City’s request for proposals process. City staff are currently working out an agreement with Ameresco to sign a 25-year power purchase agreement.

Ameresco will pay for the facility up front, reducing the City’s financial risk. The Wastewater Utility will purchase the electricity produced by the solar array from Ameresco instead of from NorthWestern Energy. After six years, the City can choose to purchase the depreciated equipment or continue under the 25-year power purchase agreement.

Missoula County also used a third-party funding model when it installed the state’s largest solar rooftop array at the Missoula County Detention Center in 2021. For more information on the County’s solar project, visit https://www.missoulacounty.us/government/community-development/community-planning-services/sustainability-and-community-resiliency/detention-center-solar-array-faqs-17001.

More Information:

For information on how Missoula residents can “go solar,” visit www.ci.missoula.mt.us/2275/Going-Solar.

Energy and Climate Team meeting—Resource Recovery Facility Solar Project Presentation, Feb. 10, 2022
YouTube video: https://www.youtube.com/watch?v=9IIwWYd1oC4
Presentation Slideshow (pdf)

In the News:  

KPAX, Solar panels to bring Missoula's emissions down by 3%, April 24, 2023

Missoulian, New solar array energizes Missoula, April 20, 2023

NBC Montana, Missoula takes step toward clean energy, April 20, 2023

PV Magazine article, "Montana city flips switch on 545 kW municipal solar facility", April 21, 2023 

Missoula Current article at https://missoulacurrent.com/city-solar-array

Project Contact:   Ross Mollenhauer, Engineering Manager, 406-552-6764 or  MollenhauerR@ci.missoula.mt.us

Miscellaneous Wastewater Improvement Projects

Utility Engineering staff held a public meeting on April 5, 2022, at 6:00 p.m. that included a presentation of the planned improvements to the City wastewater infrastructure. These improvements will take place at the wastewater treatment facility, Garden City Compost, and to the wastewater collection system at various locations around Missoula. Project goals, strategies, priorities, and funding will be presented for public input and comment. The Public Works & Mobility Department is pursuing a State Revolving Fund loan to pay for these improvements. 

Meeting Slideshow Presentation (pdf)

Presentation Video Recording

If you have any questions or comments after viewing the presentation, please email Adam Marsh at marsha@ci.missoula.mt.us. We will hold more informational public meetings for the individual projects once the projects are fully designed and funded.