The good news is that groundwater in Washington County is being cleaned up.
The bad news is that the cleanup effort will consume more water — up to 9.2 million gallons a day — than Woodbury and Cottage Grove, combined, typically use on a winter day.
The two cities are asking if there is some way to re-use the water before dumping it into the Mississippi River.
The volume of wasted water is huge, said Cottage Grove city engineer Jennifer Levitt.
“It’s hard to fathom, when you think about Woodbury and Cottage Grove serving almost 80,000 residents, and all those businesses,” she said. “The water being pumped should serve a purpose.”
The cleanup by 3M Co. was ordered by state officials in order to remove traces of perfluorochemicals from groundwater.
The company is currently pumping at several sites, but its plans to dig new wells in Cottage Grove are raising concerns.
The expected level of water usage would put the cleanup operation in the same league as entire cities. Woodbury and Cottage Grove, combined, use about 6.5 million gallons a day in the winter.
Officials worry that such volumes of removed water might lower the underground water levels.
“Which well is going to dry up?” county commissioner Myra Peterson asked Thursday. “There is not an inexhaustible supply of water.”
In a March 30 letter, Woodbury and Cottage Grove officials asked three state agencies — the Minnesota Pollution Control Agency, the Department of Health and the Department of Natural Resources — to form a working group to look at water re-use.
The pumped-out water might not be clean enough to drink, but ideas for re-use include large-scale irrigation or manufacturing.
3M spokesman Bill Nelson said the company was complying with an agreement made with the Pollution Control Agency.
He wouldn’t speculate about the company’s response to the calls for water re-use. The focus of 3M, he said, is removing PFCs from water. “If there is a public interest here, it is to be sure those remediations happen,” said Nelson.
That has also been the goal of state officials.
Gary Krueger, the pollution agency’s project manager of the Superfund program, said the purpose of the new wells in Cottage Grove is to keep PFCs out of the Mississippi.
Krueger said that for at least 30 years, 3M has been cleaning various pollutants out of groundwater at a former dumpsite in Woodbury. The company currently removes about 3 million gallons a day at that site.
The water is piped to another site in Cottage Grove, where it’s combined with water from other pump-out wells. The water is used to cool machinery in various 3M plants before being piped into the river.
David Jessup, Woodbury director of engineering and public works, said no increase in pumping is expected at the Woodbury site. But in Cottage Grove, 3M recently added two more wells, and it plans to dig two or three more in the next 18 months.
“We need to look at the long-term impact of taking that much water out of aquifers,” Jessup said.
The company manufactured PFCs starting in the 1940s, for use in household products such as Teflon and Scotchgard stain repellent.
It dumped PFCs into local landfills, ending in the 1970s, and traces of the chemicals were found in drinking water in 2005. The company agreed to clean the chemicals out of water in Oakdale, Lake Elmo, Woodbury and Cottage Grove.
Woodbury’s Jessup wasn’t critical of 3M. “They are attempting to be good, environmentally. Everything is being done under the permit of the MPCA,” he said.
But Peterson was critical. She links the water usage issue with other 3M environmental problems — including PFCs in water and a plan to expand use of an incinerator in Cottage Grove.
“This only adds to the idea of what 3M was before and what it is now — and that is not a good neighbor,” Peterson said.