With 3M Co. dumping more than 5 million gallons of water a day into the Mississippi River from its plant in Cottage Grove, city residents are asking for more time to scrutinize a new permit regulating how that wastewater is treated.
The Minnesota Pollution Control Agency (MPCA) opened a 30-day comment period last month on renewing 3M's wastewater treatment permit.
The comment period for the permit is to end Wednesday. After that, the decision on the permit will go to the MPCA commissioner, MPCA Citizens Board or, possibly, an administrative law judge.
New MPCA Commissioner Paul Aasen will ultimately decide on extending the comment period.
The permit lays out strict limits on the levels of chemicals, metals and other materials 3M can dump into the river in its treated water. It covers water used in manufacturing of things such as abrasives, resins, polymers, tapes, insulation and ceramics. It also covers water used for scrubbing 3M's massive hazardous waste incinerator, which destroys waste from all of 3M's operations in North America.
The proposed new permit includes two significant changes, Scott Knowles, staff engineer for the MPCA, told a crowd of about 50 people at a public meeting on the plan Wednesday in Cottage Grove.
First, it will regulate discharges of millions of gallons of tainted groundwater being pumped out of sites in Washington County where 3M dumped perfluorochemicals, or PFCs, decades ago. PFCs were produced at the Cottage Grove plant from the 1940s to 2002.
Second, the new permit targets a particularly harmful kind of PFC -- called perfluorooctane sulfonate, or PFOS -- to keep it from further impairing the Mississippi River.
