Investigation continues into the source and identity of hazardous material in the sanitary sewer system near the University of Minnesota. Two recent incidents have prompted evacuations at the University’s Twin Cities campus and in surrounding neighborhoods.
Investigators are assessing whether the material was directly discharged into the City of Minneapolis sewer system or the regional system, which is owned and operated by the Metropolitan Council. Both have sewer pipes near the university showing signs of black oily liquid or odor. These lines merge and carry sewage to the Metropolitan Wastewater Treatment Plant in Saint Paul.
The Met Council is leading the investigation in coordination with the Minnesota Pollution Control Agency (MPCA). The two agencies are collecting samples for lab analysis and analyzing information from interagency monitoring, emergency responders, public works officials in Minneapolis and Saint Paul, hired contractors, and observations on incoming sewage to the Metro Plant.
“We have more wastewater samples from the second incident than we did the first,” said Ned Smith, who is overseeing the Met Council’s search for answers. “We are following up with industries in the area and at locations with large storage tanks for petroleum or other hazardous liquids."
Industrial users of the wastewater system are required to have permits and periodic monitoring with the Met Council’s Industrial Waste and Pollution Prevention group. Storage tanks are regulated through the MPCA.
Smith says anyone with information about a large disposal of a hazardous material into the sewer system is urged to contact the Met Council at 651-602-4511 or the Minnesota Duty Officer at 651-649-5451. Anyone who smells gas or chemical odors should call 911.
The June 30 incident became evident when an explosion and fire occurred at a University Avenue fraternity house. Met Council crews followed reported odors and vapor readings from the university to an area near Fridley.
The Aug. 2 incident revealed itself when Met Council contractors working north of the Huntington Bank Stadium experienced eye irritation and low oxygen. Emergency responders traced odors and vapor readings north along Hennepin Avenue to Stinson Blvd. in Minneapolis.
In each case, crews worked to mitigate vapor levels and odors.
The region’s wastewater collection and treatment system includes 640 miles of sanitary sewers and nine treatment plants. Wastewater flows from homes and businesses, heads down a pipe away from the properties to a sewer pipe maintained by a city or township. That pipe then connects to a regional sanitary sewer that brings the used water to the wastewater treatment plant to be cleaned and released back into the environment.