Residuals Management & Recycle Pump Station

Residuals Management & Recycle Pump Station at Water Treatment Plant

Project Manager

City Engineering / David Barth, P.E.

SUA Project No. 20WT03

Visit the GIS Infrastructure Map to see where city infrastructure projects are happening.

What We're Doing

The City of Stillwater and the Stillwater Utilities Authority will evaluate the management and disposal of liquid and solid residuals at the Water Treatment Plant. These residuals are by-products of the treatment process. The condition and performance of the on-site lagoons, the recycle water pumping system, the overall solids handling processes and the long-term residuals plan will be reviewed.

Expected outcomes of this project include the following:

  • The Recycle Water Pump Station, which is currently in disrepair, will be replaced. The pump station is used to convey water from the lagoons to the raw water tank for treatment. The recycle process allows the City to benefit from a significant volume of water that would otherwise be acquired from Kaw Lake, a more expensive conveyance system. This represents an economic savings to the City of Stillwater as well as an environmental benefit.
  • Hydraulic assessments will be conducted for the recycle pump station intakes and discharge lines as well as for the wasting process from the filters and solids contact units to the lagoons.
  • Laboratory testing will be conducted on the City's residuals to determine settling and thickening ability.
  • Alternatives for rehabilitation of the lagoons will be developed and evaluated. The lagoons are in poor condition, and action is required to extend their service life.
  • Alternatives for long-term disposal or re-use of both the liquid and solid residuals will be explored. 
  • A Residuals Management Plan will be prepared for DEQ to describe how the City manages residuals produced from the Water Treatment Plant.

Anticipated Milestones

  • Anticipated Date (Study): 2020-2021
  • Anticipated Date (Design): 2021-2022
  • Anticipated Date (Construction): 2022-2023
  • Anticipated Date (Completion): 2024

Benefits of the Project

The new recycle pump station will allow us to better manage the recycle water process and recycle as much water as allowed by the state. This improvement along with the anticipated rehabilitation and improvements to the lagoons will help us better manage the overall residuals process and plan for future growth of our system.

Budget & Funding

  • Year Funded: FY2020
  • Funding Source: Water Capital Fund
  • Project Budget: $380,000 for design
  • Expenditures to date: $54,000

Project Management


February 4, 2020: Stillwater Utilities Authority approved a Professional Services Agreement with Carollo Engineers to evaluate the residuals management process at the WTP, design a new Recycle Water Pump Station, develop lagoon rehabilitation alternatives, develop an engineering report of their findings and prepare a Residuals Management Plan.

April 8, 2021: Carollo hosted a workshop for the City in March 2021 to present initial findings during the study phase. 

Actions Authorized by Stillwater Utilities Authority (SUA)

  • 2.3.20  | SUA-20-02 |  Professional Services Agreement


Aerial of the Water Treatment Plant showing the lagoons on the west side.

recycle pump station showing rusted and old pumps