Metropolitan Wastewater Treatment Plant (WWTP) Secondary Renewal Project
Project Update - November 29, 2022 (PDF)
The aeration process is the heart of a wastewater treatment plant (WWTP). This is where waste is broken down and converted into inert organic material by microorganisms. The aeration process at the Metropolitan WWTP has not been rehabilitated since its installation in 2000.
As the largest WWTP in Minnesota, the Metropolitan WWTP aeration process is the work horse of MCES system and serves over 1.8 million people. It is responsible for treating over 170 million gallons of daily wastewater.
This project is needed to replace the existing aeration equipment at the Metropolitan WWTP and modernize its control and materials to industry standards of process performance and efficiency. Photo 1: Existing aeration diffuser grid at the Metropolitan WWTP, to be replaced during this project.
The scope focuses on the replacement of the aeration system equipment with a few additional minor replacements in secondary treatment that support the aeration process. Below is the full scope of the project items.
- Aeration Tank Diffuser Replacement: the project will remove existing aeration equipment and replace it with new in all 16 aeration tanks. The plant will be switching from ceramic diffusers to membrane diffusers during this upgrade. This will help decrease the maintenance requirement for the 340,000 diffusers at the Metro Plant.
- Aeration Control Upgrades: The project will increase the number of remotely controlled aeration valves and upgrade system monitoring equipment. This will help plant staff better control plant processes and lead to improved energy efficiency.
- Final Settling Tank Backfill Gates: The project will be adding backup gates to the final settling tanks, allowing for gates to be repaired and replaced without taking tanks out of service.
- Underdrain and Meter Pit Rehabilitation: The project will be rehabilitating the meter pits and underdrains. These areas have not been touched since the 1960s and help the plant control groundwater levels.
- Air Header Gasket Repair: The large diameter pipe that provides air to the aeration process has a series of leaks. This project will test out a novel repair method that would allow staff to address leaks without taking down the aeration process.
- Revit Model: The project also includes creating a 3D model of the aeration tanks as well as meter pits and underdrains. This model will help operations and maintenance activities and future project work.
Notice to proceed was issued on February 22, 2021.
Substantial completion of the project is tentatively scheduled for August 2025, with the final completion following in October 2025.
Project Update - October 27, 2022 (PDF)
Project Update - September 2022 (PDF)
Project Update - August 30, 2022 (PDF)
Project Update - June 2, 2022 (PDF)
Project Manager: Mark Lundgren, Senior Engineer, Plant Engineering
Council's Authorized Representative: Mike Olerich, Principal Contract Administrator, Construction Services
For information, please contact:
Principal Contract Administrator, Construction Services
Phone: 651.602.8908 (office)
Senior Engineer, Plant Engineering
Phone: 651.302.1868 (office)