Underway: MPCA environmental review of Owatonna's wastewater treatment expansion

Contact: Cathy Malakowsky, 507-206-2608

Owatonna wastewater treatment facilityTo accommodate a growing population and reduce pollution in several rivers, the City of Owatonna in southern Minnesota is proposing to expand and upgrade its wastewater treatment facility. The city plans to nearly double its treatment capacity from 5 million to 9.1 million gallons of wastewater per day.

The treated wastewater is discharged to the Straight River. To protect the river and downstream waters, the Minnesota Pollution Control Agency (MPCA) has drafted a permit for the discharged wastewater that would limit several potential pollutants. The MPCA is proposing two stricter limits in the permit, one for phosphorus and one for hexavalent chromium.

Under the proposed new limits, the facility would need to decrease the amount of phosphorus it discharges by 27 percent, from 7.6 tons to 5.5 tons per year. Less phosphorus in the river and downstream Lake Byllesby would help curb excess algae, which is detrimental to fish, other aquatic life, and recreation.

The MPCA also proposes lowering the limit for hexavalent chromium, a chemical used in many industrial processes such as metal plating, from the current limit of 39 parts per billion a day to 29 parts per billion a day. Hexavalent chromium can be toxic to human and aquatic life if ingested at high levels.

The Straight River, which flows 56 miles from south to north, through Owatonna and Medford, and into the Cannon River in Faribault, is designated as a state water trail for recreational uses. Scientists have found that the river has several water quality challenges, including levels of sediment and bacteria too high at times to meet water quality standards. Improving wastewater treatment in the watershed is an important strategy to reducing pollutants in the Straight River and downstream waters, including the Cannon River, Lake Byllesby, Lake Pepin, and the Mississippi River.

Lake ByllesbyUnder state rules, Owatonna’s wastewater treatment expansion requires an environmental assessment worksheet, a tool that government units use to gather information for deciding whether a more extensive environmental impact statement is needed. The worksheet describes the project’s potential effects on nearby land uses, geography, bodies of water or groundwater, and wildlife and habitat. It also details air and vehicle emissions, dust, traffic, noise, and odors that the project might produce. The MPCA is asking for public comments on the worksheet through May 3.

The city will add one building and several new components to the facility at its current location northeast of the intersection of Hoffman Drive Northwest and State Avenue. The site is bordered by farmland to the north; commercial areas to the west and south; and the Straight River, commercial areas, and residential areas to the east. Construction is expected to start in 2022 and last 24-30 months. The city will continue to use its existing treatment system during construction. In addition to increasing its treatment capacity and meeting new state limits on pollutants, the project will address the problem of aging infrastructure.

No impact is expected to the North Straight River Parkway, a 2.3 mile recreational trail that runs between the facility’s east property line and the Straight River.

The environmental assessment worksheet is available on the MPCA website. The project requires an updated wastewater discharge permit, available online at MPCA's Public notes web page (scroll to March 1), which will also be open for comment at the same time. Comments on both, which must be in writing, are due by 4:30 p.m. on Monday, May 3 to:

  • Environmental assessment worksheet: Kim Grosenheider (651-757-2170) MPCA, 520 Lafayette Road N., St. Paul, MN 55155-4194 or.
  • Wastewater discharge permit: Holly Mikkelson (218-316-3860), 7678 College Road, Suite 105, Baxter, MN 56425