MPCA Media Contact:
Nancy Miller (507) 280-3590
City of Mankato Contact:
Shelly Schulz (507) 387-8516
Mankato Energy Center Contact:
John Flumerfelt (207) 671-1621
Mankato, Minn. ¾ The Minnesota Pollution Control Agency recently re-issued a National Pollutant Discharge Elimination System permit to the city of Mankato Wastewater Treatment Facility. Though the permit is consistent with existing rules and regulations for municipal wastewater treatment facilities, it is unique in that it highlights a unusual partnership between the city of Mankato and Calpine Corporation.
Calpine, an energy production company based in California, and Mankato have entered into an agreement to construct and operate a new water reclamation facility adjacent to the city’s existing wastewater treatment plant. The outflow, or effluent, from the existing wastewater treatment plant will enter the water reclamation facility for additional treatment before being routed to Calpine’s Mankato Energy Center, a power plant currently under construction. The Calpine plant will use the reclaimed water for processing and cooling. The agreement is the first of its kind in Minnesota.
The water reclamation facility will be designed to provide two additional stages of treatment to effluent from the existing wastewater plant. The first stage involves supplemental phosphorus removal that will reduce the phosphorus concentration to 0.9 parts per million. The second stage includes additional filtration and chlorination to ensure that the water will meet a standard typically reserved for crop irrigation.
Gene Soderbeck, a Municipal Wastewater Supervisor for the Minnesota Pollution Control Agency states, “The city of Mankato and Calpine partnership represents a win/win for industry and the environment. The water reclamation facility will create a beneficial re-use of treated effluent while ultimately reducing the amount of phosphorus entering the Minnesota River – a true success story for the State of Minnesota.”
In addition to reducing the total phosphorus load to the Minnesota River, the water reclamation facility offers a variety of other environmental and economic benefits. Calpine’s use of reclaimed water replaces the more typical practice of using of surface or ground water for processing and cooling.
Use of reclaimed water also eliminates the need for Calpine to introduce new water collection or discharge points along the Minnesota River. The partnership also provides cost-sharing benefits to Calpine and the city as well as economic growth opportunities for the region.
“Calpine is pleased to be part of such an innovative, inclusive approach to improving water quality in the Minnesota River. This water supply agreement is consistent with our efforts to be an environmentally responsible corporate citizen and will help us provide clean, reliable electric power to consumers in Minnesota,” says Kent Morton, Calpine Project Development Director.
Calpine Corporation will provide approximately $10 million for construction and operation of the water reclamation facility. Certified wastewater operators from the city of Mankato will run the facility in conjunction with the existing treatment plant.
According to George Rosati, Mankato Director of Public Works, “In addition to providing advanced treatment of Mankato’s water, this agreement has essentially saved local taxpayers millions of dollars. Using recycled water instead of taking it from ground-water wells is an additional advantage. Everyone benefits from the quality water we are returning to the Minnesota River.”
For more information, contact:
MPCA – Wastewater Unit
Director of Government and Public Affairs
Calpine Corporation – Northeast Region
Public Information Director
City of Mankato, Minnesota