The Rochelle City Council unanimously approved a $136,300 engineering agreement with Willett, Hofmann & Associates on March 23 for design of an addition to Rochelle Municipal Utilities’ wastewater treatment plant needed for chemical phosphorus removal and replacing a domestic lift station control panel.
By 2030, the city anticipates a phosphorous limit that it will not be able to meet with its current infrastructure. The addition to the current structure will house bulk tank and day tank(s), all necessary piping, a phosphorus analyzer and SCADA upgrades. The upgrade for chemical phosphorus removal will be the backup to the plant’s current biological phosphorus removal.
The current lift station control panel has electrical issues and one drive to operate three pumps, RMU Superintendent of Water/Water Reclamation Adam Lanning said. The new lift station control panel will include operational upgrades.
The city has completed two phases of upgrades to its wastewater treatment plant over the past five years, which included adding biological phosphorus removal. Phosphorus will be newly regulated by the Illinois Environmental Protection Agency starting in 2030, and it can be removed biologically or chemically.
“Biologically is a process that doesn’t cost any additional money other than an upfront capital cost,” Lanning said. “There is no ongoing operating cost. Chemical treatment involves adding chemicals, so there is an upfront cost and an annual chemical cost. In addition to biological removal, as a backup and safety net we’re going to have chemical treatment incorporated starting this year.”
Lanning hopes to see the chemical phosphorus removal addition completed by summer 2027, which would give RMU two years to perfect the process before the 2030 deadline. He anticipates the improvements will cost between $1 million and $2 million.
“Construction will consist of adding large storage tanks to store the chemical and a system to inject it into the water,” Lanning said. “There’s not a large capital investment needed for that infrastructure. It will be the chemicals that will cost the most after that. The city will be prepared to meet those phosphorus regulations for the life of the plant.”
Phosphorus removal has been required in other states in the region for decades, Lanning said. The Mississippi River watershed, consisting of Wisconsin, Iowa and Illinois, sees all of its treated wastewater end up in the Gulf of Mexico, where issues are being seen with water quality due to phosphorus. Lanning said he and his team have made trips to treatment plants in cities in Wisconsin that utilize the practice to bring knowledge back to Rochelle.
The RMU wastewater department works to follow ever-changing IEPA regulations closely so it can stay ahead of requirements. The first wastewater treatment plant upgrade phase was completed in 2020 and included biological phosphorus removal.
“I wanted to split that upgrade into two phases so we could learn from our mistakes in the first phase,” Lanning said. “We’ve implemented it and done it well ahead of our required timeline and then we’re doing the last stage of it in chemical removal. Staying ahead and understanding these regulations gets us ahead of the deadline for removing phosphorus.”
Lanning said he’s been “very happy” with the results of the recent improvements at the wastewater treatment plant. Once the chemical phosphorus removal system is added, he’s confident RMU will meet the limits and be within compliance for “a long time.”
RMU’s wastewater treatment plant was built in the 1990s. It has seen about $20 million in investment in recent years, Lanning said, with replacement of almost all mechanical components.
“We won’t have to worry about any large-scale improvements at the wastewater treatment plant for the next 20-plus years,” Lanning said. “With this last little phase for chemical phosphorus removal, it’s going to be minor upgrades for a long time, like rehabbing a lift station here and there. With the collection system, we’ve done miles of lining of sewers and manholes and now we’ve put about $20 million into the wastewater treatment plant. Our wastewater infrastructure will be in good shape for 20-plus years.”
If a municipality’s water or wastewater infrastructure becomes out of compliance with the IEPA, the state organization has the authority to demand a town build a new treatment plant and increase billing rates to pay for it. That has not been the case in Rochelle.
“We’ve been in perfect compliance for years,” Lanning said. “And that’s important. We don’t have the IEPA demanding or dictating that we build a new plant or add something to the plant, which would reflect on homeowners’ water bills. It’s very important. We do everything we can to keep the rates low and make the investments to stay ahead and out of trouble with the IEPA.”