Did you smell something foul overnight in Utica?

Village officials said Wednesday the cause was an algae bloom at the wastewater treatment plant, but the Illinois Environmental Protection Agency pushed back against the village’s statements and said the odor arose from untreated or partially treated sewage discharged into the Illinois River.

Both the village and the EPA agreed there was a foul odor that sparked a complaint and set off an inquiry. After that, however, the stories diverge.

Mayor David Stewart and Village Engineer Kevin Heitz said the smell was from an algae bloom in the lagoon of the village’s wastewater treatment plant. The problem was complicated by low oxygen levels in one of the cells, one of the components in wastewater treatment, officials said.

“I’m going off the information given to me by the department of public works and they said there’s nothing in [the river],” Stewart said early Wednesday. “We’re still waiting for EPA results, but I’m very confident it was not raw sewage.”

Heitz said workers were introducing oxygen into the treatment system to reduce the emission of hydrogen sulfide gas, which was the likely cause of the foul smell. Hydrogen sulfide is a colorless gas known for its “rotten egg” odor.

“Any time you get a little bit of a spike, it can become pungent,” Heitz said.

On Wednesday, both Stewart and Heitz said the IEPA had approved the village’s plan to resolve the situation at the wastewater treatment plant, but later that day, an IEPA spokeswoman disputed the village’s characterization of what happened.

“From the Illinois EPA’s investigation, it appears that the effluent from the Village of North Utica Sewage Treatment Plant is wastewater [sewage] that has not received adequate treatment,” said Kim Biggs, public information officer for the IEPA.

“The Illinois EPA is awaiting the results from samples collected at the sewage treatment plant and in the Illinois River to confirm the level of treatment,” Biggs said. “The discharge from the facility caused a decrease in the level of dissolved oxygen in the Illinois River downstream from the facility’s outfall and offensive conditions in the Illinois River.”

Biggs, who did not have a timeline for the release of the test results, also directly contradicted the village’s conclusion about an algae bloom.

Biggs said the smell coming from the sewage treatment plant was abnormal, and denied that the IEPA had approved a village plan to remediate the low oxygen levels.

“Illinois EPA staff had a conference call with chief wastewater operator and public works director earlier [Wednesday], in which IEPA was told what steps the local officials planned to take to start to fix the broken equipment at the plant. Also discussed were steps that the Village would take to stop the discharge to the river,” Biggs said in a statement.

When advised of the IEPA comment, Stewart issued the following statement:

“The village does not feel it needs to defend its previous statement regarding algae bloom. Algae bloom is the sign of a problem. The village recognizes this, and is taking the necessary steps to remedy the situation.

“Yesterday, there was verbal communication between members of the IEPA and the village superintendent of public Works. Based off that communication, everyone seemed to be in agreement with the village’s action plan.”