Reuse of waste ash in fields spreading

Researchers at the University of Minnesota are currently at the forefront of research regarding the reuse of waste ash from the Metro Plant as a possible fertilizer for crops like corn and soybeans. The plant, which is the biggest wastewater treatment facility in Minneapolis, burns the sludge that remains after the entire wastewater treatment process is completed. This burning results in approximately 40 tons per day of ash produced.

Typically that ash is hauled to a Rosemount landfill. But, last week it wasn’t. U of M researchers sprinkled bags of the ash on a farm field on the UMore campus. The field is split into dozens of segments with varying ash and alternative fertilizer applications.

Dr. Carl Rosen, head of the University of Minnesota's Department of Soil, Water, and Climate, says “You’d be getting a benefit from it (the ash)... You’d actually be able to potentially even sell it.”

Should the ash be proven effective and safe as a fertilizer, it holds the potential to cut the Met Council’s landfill costs and make much better use of the phosphorus contained in the sludge. Phosphorus is a limited resource that’s largely mined domestically in Florida.

The study will take place over three growing seasons and is funded by a sizable $600,000 grant that will mostly be funding detailed and meticulous lab work.

Met Council Principal Engineer Christine Voigt summarizes the issue this breakthrough could solve “In part of the world we’re digging phosphorus up and we’re paying to dig it up and then here we’re paying to bury it. It doesn’t make sense and it’s not sustainable.”