Wastewater Treatment Plant Disinfection and Ammonia Removal Improvements

Wastewater Treatment Plant Disinfection and Ammonia Removal Improvements
Cutting edge technologies such as high speed turbo blowers reduce energy consumption and provide air to the bioreactors in the most efficient way possible.
Wastewater Treatment Plant Disinfection and Ammonia Removal Improvements
To efficiently treat the full future flow of the plant, a UV disinfection system with the ability to turn off and on was designed to fit inside an existing tank.
Wastewater Treatment Plant Disinfection and Ammonia Removal Improvements
To reduce future O&M and painting costs, a secondary clarifier mechanism was installed in full corrosion-resistant stainless steel.
Wastewater Treatment Plant Disinfection and Ammonia Removal Improvements
Special visual mitigation was provided to match new infrastructure with existing facilities.
City of Great Falls
Great Falls, Montana, USA

Maximizing the Potential

In order to anticipate challenges and quickly solve problems for the city's wastewater treatment plant, it was imperative to plan ahead of pending regulations imposed on the plant's discharge to the Missouri River. Regulatory requirements through Great Falls' new Montana Pollutant Discharge Elimination System (MPDES) permit, required improvement designs that would bring critical discharge permit limits for metals discharge, flow metering, ammonia, and E.coli into compliance.

Even before new disinfection and ammonia removal designs to meet the regulations started, an extensive baseline river sampling survey both upstream and downstream of the outfall was developed. With this baseline sampling done, the metals limits could be eliminated as a concern. The design of new facilities needed to maximize treatment technologies for disinfection and ammonia removal were used to get the desired discharge permit requirements while providing for accurate influent and effluent flow measurement.

Design improvements included reconfiguration of existing aeration basins into two biological reactors (bioreactors) for reduction of ammonia and nitrogen and a new ultraviolet (UV) light disinfection system within the existing disinfection tank. The bioreactors were designed so that a single sensor controls oxygen feed to both reactors, minimizing the need for expensive analytical and controls equipment. This process also utilizes denitrification, the use of oxygen in nitrate, to minimize the amount of dissolved oxygen required to achieve treatment limits. The implementation of the denitrification process optimized energy usage and cost.

Additional considerations were also taken to visually blend the new facilities since the wastewater treatment plant is located adjacent to an active pedestrian trail. Designers matched brick fascia elements to blend into existing infrastructure while masking the industrial nature of the facility.

Award

  • 2015 - First Place, Best Projects Award, Engineering News-Record Mountain States
  • Professional Services: Nutrient Management & Reduction, Regulatory Compliance
  • Project Type: Wastewater Treatment, Water
  • Related Projects: Wastewater, Water