Wastewater Facilities Expansion

Rendering of Wastewater expansion


The City has continued to grow since the last Facility Upgrade started in 2005. The City's population is projected to increase from a current population of 33,966 to 40,948 in 2030.

The current facility, originally built in 1982 and upgraded in 2005 has outlived its projected lifespan. The new upgrades to the facility, slated to be completed in 2022 will allow the WPCF to better serve the growing community of Sun Prairie. In addition to increase capacity, the new facility complies with new DNR requirements to decrease the levels of phosphorous entering the watershed.

About the project

The City developed and evaluated the Wastewater Facilities Plan along with MSA Professional Services, Inc. and Donohue Associates. The Facilities Plan recommends improvements based on cost effectiveness, new phosphorous requirements set by the DNR, compliance with the City's discharge permit and the City's projected growth over the next 20 years. The total cost of the facilities upgrade is $19.9 million dollars and will be funded by an existing City Fund Contribution and a low-interest loan from the DNR Clean Water Fund.  

C.D. Smith was hired as the General Contractor for improvements to the Sun Prairie Water Pollution Control Facility (WPCF). The project consists of selective demolition and upgrades within 15 existing structures and new construction for eight structures.  The new structures include:  two final clarifiers, two primary clarifiers, one fermenter/gravity thickener, sludge pump room, sidestream pump station, coagulation/floc tank for tertiary filtration, and Vac Truck/debris drying bed.

Major upgrades to existing building and processes are as follows:  new tertiary disc filter to achieve low level phosphorus limits, new fine screen and wash press, four new influent pumps, two new aeration blowers, HVAC upgrades, and effluent water reuse upgrades.

September 2021 Construction Progress


The project is currently progressing as planned and is on budget and on schedule.  Project substantial completion is still on target to meet the December 31st 2021 deadline.  Currently the project is at the 80% + overall completion mark.  The majority of the new structures are complete and several of the new pieces of the equipment have been started up.     

October 2020 Construction Progress

Photo of construction at the Wastewater Treatment Plant

Summary Description

General Contractor:  C.D. Smith

Project Cost:   $19.9 million

Project Detail:  Multiple Buildings

Projected Completion:  June 2022

Engineers:  MSA Professional Services and Donohue Associates

Preliminary Timeline

Revised 09/2018

Submit Design Plans and Specifications9/30/2019
Open Bids for Construction11/12/2019
Construction Progress Report #112/31/2020
Construction Progress Report #212/31/2021
Complete Construction and Achieve Compliance06/2022