Rare testing opportunity shows positive results
The Minnesota Pollution Control Agency recently released results of testing on the Minnesota River that shows significant improvements in pollution levels in the river.
“It’s often difficult to show environmental gains because it can take decades to show significant progress. Therefore when we have achievements, we need to celebrate them,” says MPCA Commissioner John Linc Stine. “This happy discovery really emphasizes that environmental advances are long term and the resources dedicated are worth it.” Stine says.
Minnesota River Basin: Study area
For three weeks in August, MPCA staff monitored the Minnesota River to see if this hot, dry summer caused low dissolved oxygen in a 20 mile stretch of the river, which has been a problem in the past under similar conditions. The results pleased MPCA scientists because it shows that dissolved oxygen levels are good and supporting fish and other aquatic life even during stressful environmental conditions like low flow and high temperatures.
The testing was important to do because low dissolved oxygen can cause problems for aquatic life when the river is at low flow and the water temperature is higher than normal. These results also point to the effectiveness of a 2004 MPCA plan and a phosphorus reduction permit that affected wastewater treatment plants along the Minnesota River and its tributaries.
According to Glenn Skuta, MPCA water monitoring manager, “Over the past several years, wastewater treatment plants along the affected stretch of the river implemented several phosphorus reduction strategies that are working based on the good dissolved oxygen levels we found in this survey. There were no violations of the dissolved oxygen water quality standard.”
Some of these strategies include:
- Stabilization ponds avoiding discharge from June through September.
- Upgraded wastewater treatment for 12 communities with inadequate sewage treatment.
- Improved phosphorus removal in wastewater treatment that surpassed permitted goals for wastewater phosphorus loading to the basin ahead of schedule.
The permit also established a phosphorus trading program to allow new and existing permitted facilities flexibility in how they comply with wastewater effluent limits.
Skuta is pleased with their efforts, “The wastewater treatment plants covered by the permit collectively achieved the 2015 goal well in advance of the deadline. This is an excellent example of local government collaborating with industrial dischargers to realize an environmental outcome—improved water quality. The cities, businesses, and Metropolitan Council Environmental Services, who have all improved their wastewater treatment, deserve credit for their good work in protecting the river.”
Additionally, further work needs to continue on cleaning up things like sediment and bacteria in the river at higher flows, including agricultural soil and water conservation practices and urban storm water management.