MANKATO, Minn. (KEYC) — According to the Mankato City Council and the Minnesota Pollution Control Agency, sections of the Minnesota River are currently impaired due to low dissolved oxygen.
One cause is excess phosphorous in the river.
“Elevated levels of phosphorous does aid to the growth of algae and other forms of biological life that eat off of phosphorous in there,” said Josh Gad, superintendent at the City of Mankato Water Resource Recovery Facility.
According to the city council, to mitigate this impact, the MPCA has assigned phosphorus limits. In order to assist those communities that were not able to meet the phosphorus requirements, the City of Mankato trades the excess phosphorus as credits to those who need it.
That’s where phosphorous trading comes in.
“The basins that are behind me are where we have bacteria that removes nutrients such as phosphorous from the wastewater treatment stream,” Gad said.
Gad, who runs the facility, says phosphorus trading has both environmental and economic benefits.
“For example, some of the small towns that we trade phosphorus with would have to spend tens of millions of dollars in order to remove the phosphorus that we trade with them at a much lower fiscal rate,” stated Gad.
The Mankato City Council has recently renewed phosphorous trading agreements with five cities and entities, including the City of Granite Falls, the Lower Sioux Indian Community and the City of Walnut Grove.
“And in doing that, it frees up state funds to allocate towards state projects that have a much larger impact on water quality than the Minnesota River,” Gad concluded.