Jan 21, 2021

Chloride Pollution in Wastewater Treatment Discharges to Local Lake in Minnesota

Industrial leaders have pledged to do what they can to help the flow of chloride into Minnesota's Lake Winona.

minnesota water

Industrial leaders have pledged to help the flow of chloride into Minnesota's Lake Winona during the first meeting of a citizen’s chloride committee on Jan. 19.

“We want to be a sustainable partner in this and a good steward of the land,” said Joe Gerhardt, plant manager of SunOpta. 

SunOpta is one of the industrial customers that discharge softened water into the Alexandria Lake Area Sanitary District system, reported the Echo Press. 

The committee formed to advise the sanitary district on how to handle the chloride problem. Possible solutions could result in sewer customers paying significantly more each month, however. This could also mean the removal of home water softeners. 

One possible solution involves softening city water with lime, according to the committee.

Lakes Winona, Henry and Agnes contain more salt than the state considers safe. Testing revealed another big jump in salt levels from 2019 to 2020 in Lake Winona, according to Tracy Ekola, a consultant from Hazen and Sawyer, a water quality firm hired to help the sanitary district with controlling chloride.

According to Ekola, the problem has been building for years, reported the Echo Press.

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“It took us a while to get into this and it’ll take us a while to get out,” said Ekola. “We need to get this right. Chloride is a big issue.”

It is not the fault of the plant that salt is getting into the lakes, but it requires a federal permit to discharge into Winona and it received its current permit on the condition that it lead efforts to deal with the problem.

The sanitary district plant is only supposed to discharge treated water with a salt level of 250 milligrams per liter and it is now at 652 milligrams per liter.

Efforts are focused on preventing salt from entering the sewer system in the first place and this means reducing the amount of chloride used in industry, institutions, in homes and by road crews.

“As you can see, we have a long way to go,” said Scott Gilbertson, sanitary district executive director, reported the Echo Press.

The effort does not address other pollutants that also pass through the wastewater plant, including prescription drugs and compounds.

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