Edina’s new water treatment facility tackles industrial pollution from the past
St. Paul, MN – When Edina’s new centralized water-treatment facility goes on line this week, it will be cleaning up polluted groundwater that is a legacy of the region’s industrial past.
Tucked away in the lowest level of the city’s brick-veneered parking ramp at 5116 Brookside Ave, the new facility will not be noticeable to the public, which helps to maintain the residential character of the neighborhood. And since the treatment plant occupies space where city vehicles were formerly parked, it does not intrude on the public parking above. Also, placing the facility in an existing structure saved the city the cost of buying land for a treatment plant.
The treatment facility is where water from the city’s wells that draw from the Prairie du Chien Aquifer will be cleansed of vinyl chloride, a highly toxic substance.
As he recently toured the new facility, John Stine, commissioner of the Minnesota Pollution Control Agency (MPCA), remarked, “I am very happy that people in Edina will have safe drinking water, despite pollution that occurred years ago.”
Stine added, “The MPCA is doing its utmost to see that the kind of groundwater pollution that this new treatment plant will address no longer takes place. When one considers that the MPCA spent about $500,000 in designing the plant, and that construction will cost the city of Edina about $6 million, it’s clear that it’s much less costly to prevent pollution in the first place than to deal with it later.”
When water from the city’s wells arrives at the new facility, it is first treated to remove the iron and manganese. The water then passes through an air stripper, where air is blown through the water as it trickles through layers of packing material. When the air hits the water, the vinyl chloride and other volatile organic compounds are removed.
The stripped water is then pumped into the municipal water system, where it is treated with fluorine and orthophosphate, which coats water lines throughout the system and keeps scale from accumulating in the lines. If needed, the city also has the ability to remove radium from the well water.
Another advantage of the centralized water-treatment system is that air-stripping towers will not have to be constructed at each of the municipal well sites. Since these towers would be about 40 feet tall, not having them at the well sites helps preserve the beauty of the city parks where the wells are located.
Ultimately, water from four municipal wells will be treated at the new facility. Municipal well number 2 is already hooked up to the new facility, and water from well number 7 should begin flowing to it in August. The other city wells will be connected to the new treatment plant next year.