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Photo: Ted Karlsson
Marcus Öhman, Chair Professor of Energy Engineering at Luleå University of Technology. Photo: Ted Karlsson. View original picture , opens in new tab/window

New technology to recycle phosphorus

Published: 30 June 2016

Luleå University of Technology, Umeå University, Sandviken Energi and the international company Andritz will in a joint consortium work towards a technical solution to recycle phosphorus from sewage sludge.

Sandviken Energi, Luleå University of Technology, Umeå University and the international company Andritz will in a joint consortium work towards a technical solution to recycle phosphorus from sewage sludge.

A large part of the phosphorus that enters through the food ends up in the wastewater treatment sludge and today only a small part of this is recycled. The partnership addresses the global social challenge to achieve sustainable return of phosphorus fertilizer and nutrients into productive farmland.

Availability of phosphorus decreases

The element phosphorus is essential to life and constitutes the backbone of the DNA. Phosphorus is also necessary for all biomass production and food production. A global challenge we face is that phosphorus, which is mainly extracted from a mineral called apatite, is a finite resource that is running out. There are different opinions about how long it will last, some say 50 years, and others believe that it lasts longer. Regardless, the quality of the mineral is becoming worse with more heavy metals. It is therefore important to take care of the phosphorus that today is not recycled.

Heating removes hazardous substances

– 15 years of research at Luleå University of Technology and Umeå University have shown that it is possible to bring the digestate from waste water treatment plants in an economical and energy-efficient way. This is achieved through a special way to burn the sludge with biomass. Then harmful substances can be separated and plant-available phosphorus is recycled as an ash pellet, which then can be directly used as a fertilizer, says Marcus Öhman, Professor at Luleå University of Technology and Dan Boström, Professor at Umeå University.

Research put into practice

The Professors have now found partners that make it possible to apply research into utilization in reality. A technology owner in Andritz, global leader in the area, sees a global market potential in the renovation and extension of existing plants and Sandviken Energi who want to investigate the possibility of recovering phosphorus.

Sandviken Energi is today depositing their sewage sludge in a waste facility but is looking for other options for the future, and the recycling of phosphorus is something they like to prioritize.

– We are positive to be able to contribute to the environmental effort. The project will show whether it is possible to pellet and sanitize sludge from the wastewater treatment plant in Sandviken and then burn it in our power plant. And see if it is possible to recover phosphorus that way, says Håkan Bergsten, VA Director at Sandviken Energi.

Past and ongoing research has been funded by Bio4Energy, the Swedish Research Council, The Swedish Research Council Formas, the Swedish Energy Agency, Swedish Water and the strategic innovation program BioInnovation, a joint effort by Vinnova, Formas and the Swedish Energy Agency.