Improved Wastewater Treatment Facility for City of Little Falls Protects Mississippi River Waters

Challenge

The City of Little Falls wastewater treatment facility was in need of improvements to ensure compliance with a new phosphorus limit laid out in the City's National Pollutant Discharge Elimination System permit, issued in 2016 by the Minnesota Pollution Control Agency. The City’s wastewater facility was originally constructed in 1958, with major renovations taking place in 1985 and 2002. The facility treats an average flow of 1.9 million gallons per day – generated from a population of around 8,700 residents and a few thousand more in close proximity.

Though considered a “small city” given its population, the Mississippi River flows through the heart of Little Falls and the wastewater plant serves approximately 12,000 people in total. The City takes pride in its wastewater management, and is committed to contributing clean water to the Mississippi River and cities it flows through in Minnesota, Wisconsin and beyond.

The City recognized the need for a comprehensive facility renovation in order to meet the aforementioned State regulations and to address aging infrastructure concerns – subsequently seeking an A/E firm to prepare a facility plan, design recommended improvements and then provide construction administration for the project. 

SEH’s relationship with the City and deep rooted experience in both wastewater treatment facility design and construction administration for complex, multi-year projects led to the team’s selection for this $20+ million project.   

Solution

In order to meet the new Minnesota regulations and position the wastewater facility to serve the community for years to come, SEH provided design of renovated lift stations; improved flow equalization; a new preliminary treatment building; retrofitting of aeration basins to anaerobic selectors for biological phosphorus removal; new oxidation ditches; ultraviolet light disinfection; new solids pumping and chemical treatment systems; aerobic digestion; and new mechanical, electrical and controls throughout the plant including a backup generator. Each of these improvements help ensure the reduction of phosphorus entering the Mississippi River.

One of the project team’s primary challenges involved creating a plant that is not only easy and efficient to operate – technologically savvy with automation, for example – but financially feasible. In addition, given the size of this project and financial investments by the City, the renovations needed to stand the test of time in terms of functionality and compliance.

Construction began in fall 2019, with construction requiring a significant amount of tear down and rebuilding of old components that became outdated in light of the new Minnesota regulations. The SEH team is providing construction administration, helping to keep the facility fully operational during this phase. Careful planning went into phasing construction as the improvements are being constructed on the same site as the existing facility. The project is on schedule and within budget, and the City is proud of and excited about the sound, long-term design and soon to be completed wastewater treatment facility improvements.

Of note, SEH helped the City secure $6.9 million in State of Minnesota funding, as well as $8 million in grant funding from the Minnesota Public Facilities Authority – significantly easing the financial burden for the City and its tax payers.

    Project Name
    Little Falls Wastewater Treatment Facility Improvements

    Location
    City of Little Falls, Minnesota

    Client
    City of Little Falls

    Features

    • Improvements at the City's two main pump stations
    • Improved flow equalization
    • New preliminary wastewater treatment building with fine screening and grit removal
    • Retrofitting of aeration basins to anaerobic selectors for biological phosphorus removal
    • Backup chemical phosphorus removal
    • New oxidations ditches
    • Ultraviolet light disinfection
    • New solids pumping systems
    • Aerobic digestion processes
    • Electrical and mechanical improvements
    • Secured $6.9 million in State of Minnesota funding
    • Secured $8 million in grant funding

    Services

    • Architecture
    • Civil engineering
    • Construction services
    • Environmental engineering
    • Geotechnical engineering
    • Mechanical engineering
    • Electrical engineering
    • Structural engineering
    • Survey
    • Wastewater engineering
    • Water resources engineering

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