A Minnesota Pollution Control Agency investigation is under way into a fish kill in West Fork Beaver Creek south of Danube in Renville County.
The M-P-C-A believes the cause of the low dissolved oxygen is the biological breakdown of organic material, a process that uses up oxygen in the water. The impacts of the low dissolved oxygen were evident for about 10 miles downstream. Investigators do not believe that toxic chemicals were present.
On Friday, the Minnesota Duty Officer received a report from the Southern Minnesota Beet Sugar Cooperative near Renville, stating that a valve in its wastewater treatment system had been left open the evening of Wednesday, August 14, resulting in a discharge of “non-treated water” into county ditch thirty-seven, which goes into West Fork Beaver Creek. The amount released was estimated to be more than 4,000 and less than 20,000 gallons.
The cooperative’s facility holds a water quality permit from the M-P-C-A. Discharge of untreated wastewater is not authorized by the permit.
The cooperative is working to install treatment measures, such as placing pumps to aerate water in the stream to increase dissolved oxygen levels. Other possible measures include pumping contaminated water from the stream and spreading it on land.
Treatment activities and water sampling are expected to continue over the weekend as the Minnesota Pollution Control Agency continues to investigate the incident.