Archived News Release: October 5, 2022 - At approximately 1:30 p.m. on Tuesday, Oct. 4, 2022, staff at the City of Ann Arbor Wastewater Treatment Plant discovered a discharge of partially treated wastewater due to low water levels in the ultraviolet disinfection channels, thereby causing a system shutdown to protect the equipment. The low water levels were caused by maintenance activities. The partially treated wastewater, which received all treatment except disinfection, flowed directly into the Huron River via the outfall. Plant staff worked quickly to close the outflow to the river and restore water levels to the ultraviolet disinfection system, which was completed by 2:05 p.m.
The discharge was determined to have begun at 11 a.m. and resulted in an estimated total discharge of 1,375,000 gallons. Staff is investigating adding notification alarms should this type of event happen again.
In accordance with regulatory protocols, City of Ann Arbor staff has notified the Washtenaw County Health Department and Michigan Department of Environment, Great Lakes and Energy.
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Media Contact Information
Water Recovery Unit/Wastewater Treatment Plant Manager
734.794.6450 ext. 43822
Ann Arbor has 123,851 residents, spans 28.97 square miles and is frequently recognized as a foremost place to live, learn, work, thrive and visit.
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