By Shereen Siewert
WAUSAU — A January sewer backup that dumped about 3.7 millions of gallons of raw sewage into the Wisconsin River is attracting additional review from state officials who say that the leak also resulted in hundreds of pounds of phosphorous being added to the waterway, according to city documents.
The news comes at a time when the Wisconsin Department of Natural Resources is taking aim at phosphorous in the Wisconsin River basin, tightening restrictions to improve water quality in the river and Lake Wausau. The DNR first announced a massive statewide cleanup initiative in February, while more detailed plans were announced just this week. Scientists believe phosphorus runoff contributes to algae blooms that can sicken people and kill animals.
Eric Lindman, Wausau’s director of public works and utilities, on Jan. 29 released a detailed report about the backup. Lindman said the DNR would be testing water samples to determine any potential health risk to the community but would not be issuing a fine.
Newly released water sample results, included with the DNR’s notice to the city this month, show the discharge resulted in about 600 pounds of additional phosphorous above the city’s water quality standard permit limit going into the river. As a result, the DNR is requesting the city to consider potential short- and long-term phosphorous reduction projects to improve water quality.
City officials are required to submit a response to the DNR by June 30 outlining their immediate response to the discharge, opportunities for mitigating phosphorous impacts on the river and a list of changes being planned in operations and management.
The DNR has not made a final determination on additional enforcement, according to DNR Environmental Enforcement Specialist Pamela Buss.
The overflow event, first reported on Jan. 23, is being blamed on a production run error Jan. 17 at Kraft Heinz that allowed about 670 pounds of anhydrous milkfat to be discharged into the sewer system. Anhydrous milkfat is a manufactured food material similar to butter that solidifies at room temperature.
According to a June 14 letter to the city from the Wisconsin Department of Natural Resources, city officials first learned of the error at the plant on Wednesday, Jan. 17, and immediately checked manholes from Kraft Heinz, located on Townline Road, to Grand Avenue. With no obvious malfunctions or problems in operations, city officials by Friday, Jan. 19 believed there was no cause for concern.
But on Tuesday, Jan. 23, a resident contacted the city to report a strong odor, leading to the discovery of the backup on the bank of the Wisconsin River, according to city documents. 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.
Crews worked steadily through the night pumping wastewater into tanker trucks that transported the waste to the sewer treatment plant.
Then on Wednesday, Jan. 24, utility crews discovered the pipe was not cracked after all, but was plugged, city officials said. A high pressure jetter cleared the jam, and the line was placed back in service that afternoon. About 25 percent of the city’s flow comes from the line that was plugged, according to the DNR.
Too much phosphorus in the water causes algae to grow faster than ecosystems can handle, according to the Environmental Protection Agency. Significant increases in algae harm water quality, food resources and habitats, and decrease the oxygen that fish and other aquatic life need to survive. Large growths of algae can severely reduce or eliminate oxygen in the water, leading to illnesses in fish and the death of large numbers of fish, according to the EPA.
Some algal blooms are harmful to humans because they produce elevated toxins and bacterial growth that can make people sick if they come into contact with polluted water, consume tainted fish or shellfish, or drink contaminated water.
Wausau is in the process of evaluating the city’s wastewater treatment facility and is developing a plan with Donahue & Associates that will encompass phosphorous reduction estimates.
The city spent $51,600 investigating and remediating the discharge, according to the DNR. No fish were killed as a result of the backup, the DNR letter states.DNR Letter