Wastewater Digester Lid & Miscellaneous Improvements

Wastewater Digester Lid & Miscellaneous Improvements

Project Manager

Water Utilities Engineering / David Barth, P.E.

SUA Project No. 16SG01

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What We're Doing

The City of Stillwater and Stillwater Utilities Authority is making improvements to multiple facilities at the Wastewater Treatment Plant. These include: two digesters, an automatic transfer switch, a gas collection system used for fueling the heat generation system, grease handling system, basin drains, fencing and roofing. 

Anticipated Milestones

  • Anticipated Date (Design): Design began FY2017
  • Anticipated Date (Construction): Construction began August 2018
  • Anticipated Date (Completion): November 2020

Benefits of the Project

Sludge digestion produces corrosive gases that have led to the deterioration of Digester A and B lids. 

Budget & Funding

  • Year Funded: FY2017
  • Funding Source: Wastewater Fund
  • Project Budget: $2.7 Million
  • Expenditures to Date: $340,000

Project Management


May 12, 2017: The design kickoff meeting between the City and Freese and Nichols was held on May 8th. The study phase is expected to last five months.

November 15, 2017: Bid Opening for the Automatic Transfer Switch phase occurred November 18th.

January 22, 2018: The study phase for the miscellaneous improvements at the WWTP is now complete and we are moving into final design to include:

  • New fixed cover for Digester A,
  • Gas collection/handling and safety equipment for all three digesters,
  • Aeration basin access and drainage improvements,
  • New perimeter fencing surrounding the sludge fields and plant facilities, and
  • New roofing on four buildings at the WWTP.

Construction on the Automatic Transfer Switch will begin end of January 2018.

February 27, 2018: Notice to Proceed has been issued to Dane & Associates Electric Co. for the automatic transfer switch replacement.

May 23, 2018: Design Engineer submitted preliminary design for the Digester Lid.

November 19, 2018: Final design is underway and expected to be submitted by February 2019. Bidding and Construction phase will soon follow.

May 31, 2019: Final design is nearly complete. Advertisement for bids is scheduled for June 2019. Construction will likely begin in the fall and is anticipated to last 14 months.

August 20, 2019: Bid for the Digester Lid replacement was awarded to BRB Contractors, Inc.

Actions authorized by Stillwater Utilities Authority (SUA):

  • 4.17.14  | SUA-17-08 |  Authorization of Professional Services Agreement

  • 12.04.17| SUA-17-42 |  Bid Recommendation

  • 1.22.18  | SUA-18-05 |  Professional Services Contract Amendment


View showing the poor condition of the digester lid at the waste water treatment plant