For the past several years, the federal EPA and corresponding State EPAs worked to establish phosphorus limits for wastewater for the Great Lakes basin and the Gulf of Mexico.

For Illinois, that includes farmland and municipal sewer system. McHenry County’s Fox River is part of the waterway that feeds the Mississippi River.

Since the City of Cary’s wastewater treatment effluent discharges into the Fox River, they must comply with the new limits.

Phosphorus can wreak havoc on our waterways.

According to the EPA “Phosphorus acts as a nutrient that can cause excessive algae blooms, low oxygen, and nuisance conditions that adversely impact aquatic life, drinking water, and recreational uses of the water.”

Most raw sewage contains about 4-8 mg of phosphorus in each liter of sewage. The new limits require not more than 1 mg/L of treated water discharged into environment.

According to Cary Director of Public Works Erik Morimoto, previous to these new limits, there were no specific limits. That is why Cary recently contracted with experts at Joliet Strand Associates Inc. to improve their water treatment process to meet the new requirements.

Morimoto explained that in addition to the technology needed to control the amount of phosphorus discharged into the Fox River, Cary plans to upgrade the disinfection system from chlorine treatment to ultraviolet light. The projected cost of the upgrades is $167,000. As part of the contract, “Strand will help with the documentation and preparation for low-cost loans from EPA to help defer the costs of the upgrade.”

Cary chose Strand from six interested firms. Strand ranked at the top based on the cost proposed, the result of the feasibility and engineering proposal, and their documentation expertise.

The Illinois EPA has specific steps for what needs to be done. They also review and approve the plan. Part of the permitting process requires testing and analysis of the effluent.

“There will be lots of daily testing” to prove the changes are effective, according to Morimoto.

Cary does not have a combined system for wastewater and storm water, like many other municipalities in the state. The water from storm drains are not treated as waste water. Instead, according to Morimoto, “Storm water requires some treatment like going over vegetative swales,” which help filter the water and slows the progress to rivers and streams. “Cary soils are sand and gravel, ideal for filtration.”

Unlike many older Illinois communities, most of Cary’s infrastructure is relatively new, “A lot of the community was built in the ’80s and ’90s. We have ongoing infrastructure needs, but not of the historical scale of some older communities,” said Morimoto.

Still, it’s important for the public to be aware of the limitations of water treatment facilities. Medications should be disposed at the police station or the local pharmacy and not flushed down the toilet. Only things of a biological nature should be flushed. Rags and disposable wipes wreak havoc on water treatment systems, “even when they are marketed as flushable,” said Morimoto.