COHASSET — Excavation and pumping are ongoing at Boswell Energy Center in Cohasset in response to the coal ash wastewater spill reported earlier this month.
According to the most recent update from the Minnesota Pollution Control Agency, two sump pumps are pumping the released material back into the facility’s wastewater system at a rate of 40 to 50 gallons per minute. An estimated 18,000 gallons had been removed as of Thursday, July 25.
A U.S. Environmental Protection Agency update said soil excavation began July 20. Over 250 tons of soil was removed as of July 22.
The size of the spill is estimated to be 5.5 million gallons after an apparent leak from an underground pipe.
A portion of that wastewater flowed into Blackwater Creek and Blackwater Lake, both of which are connected to the Mississippi River and Pokegama Reservoir system.
Tests have confirmed increased levels of sulfates within the creek near the lake, according to environmental contractor Barr Engineering.
The primary contaminants of concern are sulfates, chlorides and boron.
In the field, responders have been using tools to learn where the released materials are and to monitor where they may potentially migrate.
MPCA said results are fluctuating daily and are up to four days behind due to lab turn-around times, but the agency also noted that vegetation near the wastewater spill is not showing signs of stress.
The ongoing sampling and monitoring will help determine how widespread or severe the impacts are and what tools and technology will be most effective to minimize impacts.
Actions already taken to help stop the spread of pollutants include deep-skirted booms and silt curtains.
Funding for this environmental story was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources (LCCMR).
