Joliet plans $112 million upgrade at wastewater treatment plant

Joliet plans to spend $112 million to expand capacity and make other improvements at its west side wastewater treatment plant.

The plant was built in 1972, and the last major upgrade for the facility was in 2002, Utilities Director Allison Swisher told the City Council at its Sept. 17 meeting.

“We are due for significant work on that facility,” Swisher said.

Her presentation preceded a council vote approving a $6.2 million contract with Strand Associates, which will design the plant upgrades and expansion.

Construction costs alone are expected to be $97 million.

The cost of the plant upgrades has been factored in to future Joliet water and sewer rates, which will pay for the project, Swisher said.

Construction still is a couple of years away. The plan is to seek construction bids in October 2026 on a schedule that would have the upgrades completed by June 2030.

Swisher said the project is needed to increase treatment capacity, keep up with regulatory standards for wastewater and replace equipment nearing the end of its useful life.

The upgrades will increase treatment capacity from 14 million gallons a day to 18 million gallons a day when the project is done. The plant now typically handles 12 million gallons of wastewater a day.

The increased capacity will equip the plant to handle future growth in the area it serves, Swisher said.

“We need to move now so by 2030 we have that capacity,” Swisher said.

The west side plant, in addition to serving a large section of the city, also provides treatment for wastewater from the villages of Shorewood and Channahon, per agreements made with those municipalities.

The plant is located in an industrial area off of Route 6 in the vicinity of Interstate 55. It is one of three wastewater treatment plants in Joliet.