Some people come to Minneapolis for the Guthrie or the lakes. Some come to the area to shop at the Mall of America.
But the EPA's acting assistant administrator for water? She's going to see how Minneapolis handles sludge.
Nancy Stoner will get a tour Tuesday of the city's installation of a new dewatering system at the city's water treatment plant in Fridley. So why does a water plant dewater? It's because the treatment process produces a chemical sludge. Most of the water is removed from that sludge before it is trucked off to farm fields. The city used to remove water from the sludge by spinning it in a centrifuge and letting the remainder settle in a pond. But now it's switching to a filter press as part of a $25 million replacement of the centrifuges. It's not like the city hasn't gotten its money's worth from the centrifuges. They're 35 years old and the city says they've been rebuilt numerous times and were at the end of their useful life.
Because centrifuges are considered less efficient, more expensive and less environmentally friendly.than today's technology, they're being replaced. The new presses, operating something like a French press coffee pot, will remove more water before the sludge is trucked off. Trucking will be cheaper and the presses use less electricity than the old technology. The city estimates a savings of $500,000 annually. One reason that the federal bureaucrat is visiting the plant is that the EPA loaned at least $6.5 million to the project, forgiving part of the principal under its 2009 economic stimulus. She's also talking to Association of Drinking Water Administrators while here.
