The first purification barrier is mono-incineration (>850°C), which destroys pathogens and the vast majority of organic contaminants, including pharmaceuticals, pesticides, and most PFAS. Heavy metals cannot be destroyed but become concentrated in the mineral ash, facilitating their subsequent removal.
The second purification barrier is the Ash2Phos chemical extraction process. Hydrochloric acid dissolves phosphorus and metals from the ash, after which controlled precipitation and pH adjustment selectively remove heavy metals. The purified phosphorus is finally recovered as calcium phosphate. Analytical data reviewed by the DCA indicate that contaminant concentrations in the recovered product will comply with current European contaminant limits.
High-purity recycled phosphorus for future feed applications
The combination of thermal treatment of sewage sludge and chemical extraction provides multiple independent barriers against contamination, resulting in a phosphorus product with a very low probability of containing undesirable substances at concentrations of toxicological concern. This is particularly important for applications where product safety and purity are critical, including future feed phosphate ingredients. The available scientific evidence consistently supports the effectiveness of the technology.
Although current European legislation does not permit wastewater-derived phosphorus to be used in animal feed, this restriction reflects regulatory classification rather than demonstrated safety concerns.
– We don’t have to choose between purity and circularity. Ash2Phos shows that we can recover exceptionally pure phosphorus from waste, and make it part of a more resilient, sustainable future, concludes Sara Stiernström.
