Wastewater Treatment

After its permit was placed on hold, one of Union’s two wastewater treatment plants got a reprieve for at least four years from the Missouri Department of Natural Resources.

The department was reevaluating the permit after mussels were killed downstream from the plant in the Bourbeuse River.

“They’re going to reopen that permit and re-evaluate it to determine if they need to do anything further on,” City Administrator Jonathan Zimmermann told the board of the Union Development Corp. (UDC) at a Thursday, Jan. 7, meeting.

That could have required expensive upgrades to the plant, Zimmermann said.

But Zimmermann got an email after that meeting telling him about the permit being issued. The change means Union won’t have to deal with repairs for at least four years.

“This is really good news,” he told the board of aldermen at their Monday, Jan. 11, meeting. “It gives us another cycle.”

The likely reason for the change is because the Department of Natural Resources is holding off while the state considers new phosphorus limits. But Zimmermann said Union has been preparing for that.

“We’ve been sampling for it to see where we are,” he said.

In a November email, Sam Buckler, environmental program analyst with the Missouri Department of Natural Resources, told Jeff Voss, Union’s water and wastewater superintendent, that excessive amounts of nitrogen and phosphorus were found in the Bourbeuse. And the Union West Treatment Plant, located off South Highway 47, was identified as one of the sources for excessive nutrients.

The plant was last improved in 2007, Zimmermann said Thursday.

“You typically get 15 to 18 years out of a treatment plant before you have to start improving, modifying, things of that nature,” he said.

Had the west plant been limited by the state, the city has plenty of capacity available at its east plant, which goes through about 250,000 gallons of its 800,000 gallons per day capacity, Zimmermann said. But that could change.

“If you get another large water user, that capacity goes away quickly,” he said. “If you get somebody who’s using 100,000 gallons a day, then you’ve just lost 100,000 gallons of capacity.”

The state is working on a statewide total phosphorus limit for all facilities that discharge more than 1 million gallons of water each day, since nutrients are increasingly being found to be a source of water quality impairments statewide, Buckler wrote.

This is the second time in recent months mussels have become a key issue for the city. Union had to pay for a mussel study in the area of a bridge for the planned Union Expressway, which would connect the north and south portions of Highway 47. No mussel beds were found in the area of the planned bridge.

The Bourbeuse River is considered one of the state’s leading rivers as a home to endangered mussel species.