Flow Equalization Basin Improvements

Flow Equalization Basin Improvements

Project Manager

Water Resources / Peter Armans, P.E.

SUA Project No. 12SG08

What We're Doing

The City of Stillwater and Stillwater Utilities Authority is making improvements to the flow equalization basin (FEB) at the Wastewater Treatment Plant. The plant cleans the city’s sewer (wastewater) to a point where the effluent water can be discharged to a stream. The project consists of cleaning and removing all sludge, debris and grit from the FEB, replacing a sluice gate, adding new valves and sealing joints and cracks in the FEB walls.


The FEB plays an important role at the plant, providing 750,000 gallons of temporary storage for excess wastewater entering the plant during high flow periods, particularly during heavy rains. After the high-flow period subsides, the wastewater in the FEB is treated through the plant processes. 

The project started in September 2015.  



June 1, 2016: Phase 1 construction is complete. Sludge and debris were removed from the FEB, the sluice gate was replaced and a new valve was installed. Phase 2 is in design and will include joint and crack repair to the walls of the FEB, as well as upgrades to the existing liner. 

February 3, 2017: Design efforts for Phase 2 are complete. The final corrections to the documents and assembly of contract are being conducted by the City's engineer.

June 16, 2017: Bids from Contractors have been received and staff are evaluating the submittals before making a selection.

August 10, 2017: Wynn Construction Co., Inc. was awarded the construction contract.

November 15, 2017: FEB has been drained for Restek to begin sealing cracks.

December 18, 2017: Construction has begun on the FEB's new concrete liner.

Concrete Liner being poured into the FEB

February 27, 2018: The FEB liner is complete. Contractor is currently working on the sludge beds.

image of the FEB with the finished poured concrete liner

April 27, 2018: The Project is substantially complete. The Contractor is currently working in final touch-ups and restorations.

Actions Authorized by Stillwater Utilities Authority (SUA)

  • 6.15.15  | SUA-15-48 |  Recommendation of Bid

  • 8.1.16  | SUA-16-39 |  Amendment to Professional Services Agreement


Flow Equalization Basin (FEB) at the Wastewater Treatment Plant.

Flow Equalization Basin at the Wastewater Treatment Plant filled with water.

Cleaning of basin.

Cleaning of the Basin. Man in basin wearing waders.