By Shereen Siewert

WAUSAU — The Wisconsin Department of Natural Resources won’t fine the city of Wausau following a sanitary sewer overflow that dumped an estimated 3.7 million gallons of raw sewage into the Wisconsin River, according to a news release issued late Friday.

Workers had originally thought the pipe, which carries wastewater from the southeast side across Lake Wausau and into the city’s sewer treatment plant, was cracked or broken after a large sewer overflow was discovered on Jan. 23. Utility crews later discovered the pipe was not cracked after all, but was plugged.

Crews worked steadily through the night pumping wastewater into tanker trucks that transported the waste to the sewage treatment plant. A high pressure jetter cleared the jam and the line was placed back in service the next day.

The overflow occurred through a safety bypass that re-routed the sewage down the East embankment of the Wisconsin River, according to a DNR report.

The DNR is requiring the city to provide an inventory of similar bypass structures in the collection system that could cause future overflows and develop modifications to those structures. City officials say they are already working to address these issues.

Because of the city’s rapid response to stop the overflow, no fine will be assessed, according to Public Works Director Eric Lindman.