Phosphorus recovery from co-incinerated sewage sludge on a large scale

Purpose and goal

The project has in a larger pilot scale demonstrated EasyMining´s process for extracting phosphorus from ash of co-combusted sewage sludge and wood fuel. The project has provided valuable process experience, including further process flexibility with more product choices from the process. This strengthening of know-how along with patent protection, strenthened the commercialization of the process and has led to a tighter cooperation with Ragn-Sells.

Results and expected effects

The large-scale test of the phosphorus recovery process using sludge ash shows that pure phosphorus products and reagents can be recovered from co-incinerated sewage sludge and wood fuel. Providing a sustainable concept for phosphorus recycling from sewage sludge avoiding spreading of unwanted substances and infectious agents. This incineration concept avoids energy-consuming pre-drying and is adapted to Swedish conditions using existing biomass incineration plants.

Approach and implementation

The project was conducted in cooperation with Ragn-Sells AB which was responsible for the incineration and delivery of ash. Process optimization was performed in laboratory tests. The large scale run was carried out with sub-steps at Ragn-Sells site and at EasyMining. Improvements were achieved during the large-scale run, ie, a number of alternative products can be produced including feed phosphates. The obtained data was used for calculation of mass balances and scaling up of the process.