Wastewater testing proposal approved

MARSHALL — Marshall is still having issues with pollutants in its city wastewater, city staff members said Tuesday. But if the city can figure out what the source of the pollutants are, it might be able to work on a solution to the problem.

At their regular meeting, Marshall City Council members voted to approve a proposal to conduct tests to help determine the reason city wastewater is failing tests for toxicity.

City staff said the Marshall wastewater treatment facility has failed past toxicity tests and is currently in a toxicity reduction evaluation with the Minnesota Pollution Control Agency.

“There is something in the effluent causing toxicity,” said Marshall wastewater treatment superintendent Bob VanMoer. VanMoer explained that in tests, aquatic life like water fleas and minnows failed to survive in water released from the city treatment facility. It’s possible that a salty discharge is the reason for the failed tests, he said. It could also be other pollutants.

High salt levels in wastewater isn’t a new topic for the city. Council members, city staff and Marshall Municipal Utilities have all been part of discussion and planning to cut back on chlorides in Marshall wastewater. City staff said the main culprit behind the chloride levels is the heavy use of water softener salt by Marshall residents. MMU is trying to secure grant funding for a project to pre-soften its raw water, in hopes of cutting back on the need for softener salt.

VanMoer said the engineering firm of Bolton & Menk had a proposal for testing Marshall wastewater to determine the source of toxins.

A set of mock tests would also soften samples of city water and wastewater to try and determine if the plan to pre-treat Marshall water would cut down on the toxicity.

Figuring out what’s causing the toxicity will be crucial in order for Marshall to get back in compliance with its wastewater permit, city staff said.

The total estimated cost of the testing, including Bolton & Menk’s proposal and other testing fees, would be $32,376.

Council members voted 6-1 to approve the testing proposal. Council member Steven Meister cast the vote against.

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