In a press release sent out Wednesday, the city of Ann Arbor announced an estimated 75,000 gallons of “partially treated wastewater” had overflowed into the Huron River from the city of Ann Arbor’s Waste Water Treatment Plant. According to the City, staff at the treatment plant discovered what they reported as an “overflow of plant effluent water from the tertiary filter backwash wet well” at 5:30 a.m.
“The overflow, which received full treatment, except for final ultraviolet disinfection, flowed into the Huron River via a stormwater outfall,” the press release said.
During the same timeframe as the overflow, the total discharge in the Huron River was about 36 million gallons, the City explained.
The Ann Arbor Water Quality Manager Jennifer Lawson said recent heavy rains increased flow to the wastewater plant, MLive reported.
According to records from the National Weather Service, there was more than one inch of rain in Ann Arbor from Tuesday at 7 p.m. to 8 a.m. on Wednesday. The National Weather Service has issued a flood watch in Washtenaw County and other counties in Southeast Michigan from Thursday at 4 p.m. to Friday at 10 a.m.
The press release stated City staff worked quickly to address the issue. As per regulatory protocol, the City confirmed it has reported the overflow to the Michigan Department of Environment, Great Lakes and Energy.