Free Press Staff Writer

Mankato and North Mankato are considering a contribution toward a lawsuit against the Minnesota Pollution Control Agency to fight a new phosphorus regulation that won’t affect them but is one they argue will set a bad precedent.

It would impose a flat rule of phosphorus discharge from water treatment plants — of 1 milligram of phosphorus per liter of water. That may not seem like a lot, but the most polluted lake in the state has about .09 milligrams of phosphorus per liter.

Both cities share a treatment facility that is more than able to meet the new standard, slated to go into effect May 1.

“Phosphorus is not an immediate concern for Mankato/North Mankato,” North Mankato City Administrator Wendell Sande said. “The precedent set by this kind of standard is.”

He said the city is considering a donation of up to $3,000 toward the lawsuit from the sanitary sewer fund, supported by residents’ utility bills.

That amount will be lower if Mankato goes in as well, a decision it expects to make next month.

The Coalition of Greater Minnesota Cities, a lobbying and advocacy group, is considering the lawsuit because of the high cost cities bear in improving wastewater treatment, said Joe Sullivan, an attorney for the coalition.

And the standard, he said, is an across-the-board, unscientific measure that will levy unnecessary costs on cities not in danger of polluting a vulnerable watershed.

“Our issue is the rather arbitrary process of rule-making, that they don’t seem to follow the science of the rule-making,” Sullivan said.

As it stands, cities are only limited in their phosphorus pollution if the chemical will affect a downstream body of water, typically a lake, that has been declared “impaired” by the state, said Dennis Wasley, an MPCA scientist who sets phosphorus limits.

Mankato is included because the Minnesota River empties into the Lake Pepin watershed, which has been declared impaired.

But Mankato’s water treatment plant operates below its current mandate, and actually sells the right to pollute — called phosphorus “credits” — to an ethanol plant run by Granite Falls Energy.

This new standard wouldn’t affect those credits.