WORTHINGTON — The Minnesota Pollution Control Agency is continuing to gather public comment on a proposed water quality standard variance for Worthington’s wastewater treatment plant.
The city applied for a variance to the standard for chloride. If approved, the variance will give the city additional time to reduce the amount of chloride (salt) discharged as treated effluent into Okabena Creek.
Worthington Public Utilities has already been working on the process, having proposed to replace its wastewater treatment facility on the city’s north side. The existing treatment plant was built in 1962 and underwent renovations in 1983, 1989 and 2000.
The MPCA notes that while the discharge from the existing plant exceeds water quality standards for chloride, the proposed new facility would also have the potential to exceed chloride standards because current treatment options are too costly.
“Minnesota has a growing salty water problem that threatens its freshwater fish and other aquatic life,” noted Forrest Peterson, MPCA’s Southwest Region communications director. “It takes only one teaspoon of salt to pollute five gallons of water. Once in the water, there is no easy way to remove it.”
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According to the MPCA, wastewater treatment facilities can be major contributors of chloride to lakes and rivers. In the Des Moines River Watershed, the Worthington wastewater treatment plant is among several contributing to a downstream impairment. The variance will not further impair the water, and will put the city on a path to reduce chloride discharging to Okabena Creek.
The facility’s current permit expired March 31, 2016. The MPCA notes the new construction will not change the location of the discharge to Okabena Creek, or the facility’s wet-weather design flow of 4 million gallons per day (mgd). The average dry-weather design flow will increase from 1.45 mgd to 2.15 mgd, but this will not result in an increase of the permitted pollutant load discharged from the facility.
Worthington Public Utilities has worked with Bolton and Menk for approximately three years to evaluate the city’s current wastewater treatment plant. A new facility is planned at an estimated construction cost of more than $21 million. The project will include a new treatment for wastewater that will remove phosphorus and other harmful nutrients from wastewater before discharge.
Final design work is anticipated to be completed late this spring, and it will go out for bid in late May or early June. If all goes as planned, the two-year construction process could begin as early as August.
People who wish to view the city’s draft permit with the MPCA, as well as related documents, may do so by visiting pca.state.mn.us/water/water-quality-variances. Written comments are due by 4:30 p.m. Feb. 12 to ashley.wahl@state.mn.us . Comments must include a statement of the respondent’s interest in the report and the action requested of the MPCA, including specific references to sections of the draft document that should be changed as well as the reasons for those changes.
