Finding a new use for incinerator ash

March 24, 2017
A photo of a young woman in a lab holding a container of light brown dust

It just looks like a fine, light brown dust, but Land and Atmospheric Science student Persephone Ma sees the potential for something more. This is ash, left over from a wastewater treatment plant that burns sludge to help power to the facility. The plant is operated by the Metropolitan Council, but they have a problem. What to do with that leftover ash? 

Persephone Ma, with her advisor Dr. Carl Rosen, may have a solution. They think it could be used as an agricultural phosphorus fertilizer.

“There are two potential big benefits,” Persephone explains. “The ash is kept out of landfills and farmers get access to a new, phosphorus fertilizer.” Phosphorus is a limited resource, most of it used in the US  is mined in Florida. As this resource is depleted, more will come from overseas.  

But before the ash can be used to grow crops, two main questions need to be answered. First, does it work? Will the ash help the soil and the crops? Secondly, is it worth it? For the project to succeed, it has to be cost effective and easy to use.

Thanks to funding from the Metropolitan Council, Ma and Rosen plan to start field trials this summer. The hope is the project will provide benefits to the people of the Twin Cities and farmers in greater Minnesota. 

Photo and article by Stacy Nordstrom