When sewage comes into Cary’s wastewater treatment plant, it goes through a series of tanks, digesters and clarifiers. At times during that process, the water is a nice brown chocolate color with a little bit of foam.
That activated sludge means microbes are breaking down the sewage and absorbing nutrients as a natural way of processing wastewater.
Eventually the water becomes clear and is discharged into the Fox River.
The process might be adjusted or a step might be added at the Cary plant, as the village awaits for new requirements from the Illinois Environmental Protection Agency.
Permits for Cary and Fox River Grove to run their wastewater treatment plants have expired, and they are awaiting their new five-year permits from the IEPA.
The main sticking point for the permits is how much phosphorous the plants will be required to filter out of the wastewater before discharging it into the Fox River. Downstream communities, such as Elgin, filter water from the river to make potable water.
Depending on that requirement, the two villages might have to make upgrades to their wastewater treatment plants.
Amy Dragovich, the Northern Unit manager for the Permit Section of the Bureau of Water of the IEPA, said the agency is considering having a requirement that phosphorous be filtered down to 1 milligram per liter.
Wastewater treatment plants such as Woodstock North, Wonder Lake and Crystal Lake already have the requirement in their permits, Dragovich said.
She added the IEPA hopes to have permits for Cary and Fox River Grove issued by September.
There is a study taking place of the Fox River watershed, and the results of the study will help determine the phosphorous requirements, Dragovich said.
Phosphorous can help lead to algae blooms, which make water for downstream communities harder to filter and use, and make it more difficult for aquatic river life to flourish.
Although Cary has yet to do an analysis of what could be done to the plant and how much it could potentially cost, it put a placeholder in its capital plan of $800,000.
How much that upgrade would cost depends on the method the village decides to use to take out the phosphorous, as the village can use biological or a chemical route.
Using chemicals along the current process to remove phosphorous has continuing costs associated with the new materials, said Assistant Public Works Director Mike Walsh.
Using a biological process, a more natural process, has a higher upfront cost. It would require adding a step to the plant’s filtering process, Walsh said.
Public Works Director Erik Morimoto said the village is preparing to start a feasibility study to determine which route to go.
How the potential upgrades will affect user rates has yet to be determined, especially as the project cost still is unknown. The village does have 3 percent annual increases planned through April 2018 to help cover the cost of operating the plant.
“As we go through the process of determining which preferred option we’re going to go with, then we’ll work with our finance department and our budgetary process to determine that next step,” Morimoto said. “At this point it’s a little too early to determine the impacts on rates.”
He added there is space at the Cary plant in case an expansion is needed, as the plant was designed with future growth in mind. There are extra tanks that can be repurposed to keep the costs down without losing operational efficiency.
“We’re fortunate to have some flexibility with our infrastructure, which will hopefully play in our favor,” Morimoto said.
Fox River Grove last year raised its sewer rates 5 percent to start putting money away for a potential upgrade and other one-time large capital purchases.
“At a certain point, there could be IEPA regulations that require us to do a facility expansion,” Fox River Grove Village Administrator Derek Soderholm said. “How big that expansion is, or what is required depends on what the regulation is. The more stringent it is, the more costs there would be.”
Soderholm said the village is initially estimating an expansion would cost $3 million to $5 million in today’s dollars.
The village anticipates an expansion will eventually have to come, but it may not be required as part of the village’s next five-year permit.
A 2.8 percent rate increase this year was meant to keep up with the costs of running the plant.
Whether the village would have to do an additional large increase in the future will depend on how much it is able to put aside and has to borrow when an expansion or upgrade is carried out.
“We’re doing financial planning to attempt to avoid any large increase [in rates] down the road,” Soderholm said.