According to the DNR, groundwater samples from around the ponds have shown concentrations of boron above state groundwater quality standards and elevated levels of arsenic and sulfate.

Wisconsin law does not require testing for mercury at coal ash landfills.

There are no wells within a half-mile radius that aren’t owned by Alliant, but Wannier said if contaminated groundwater finds its way into surface water Alliant should be subject to DNR authority.

Bill Skalitzky, Alliant’s manager of environmental services, said the company is in the “preliminary phases” of exploring dry-ash handling for Columbia. He said a dry-ash system will need to be in place by 2023, when Alliant must stop using the settling ponds to comply with a different set of federal rules.

Alliant estimates there is up to 1.1 million cubic yards of ash and wastewater stored in the main settling pond and a second inactive pond, according to the company’s plans for closing the ponds.

Skalitzky said while dry ash handling systems cost more to install they also have advantages, including less down-time for boilers. Alliant has installed dry-handling systems at two of its plants.

But Wannier said without enforcement by the DNR there’s no guarantee that Alliant wouldn’t continue handling the ash with water and transporting it somewhere else for treatment.

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