Phosphor Recovery - LEACHPHOS*

Phosphor is a secondary resource available in municipal sludge of Waste Water Treatment Plants. BSH developed a recovery technology (urban mining) with wet-chemical processes from a thermal sewage sludge treatment plant (mono-incineration) based on the Fluwa process in cooperation with ZAR and AWEL (waste related public entities of the Canton of Zurich) and verified the technology in a demonstration plant (EWB Bern). The BSH Leachphos* process consists of

  • Wet chemical extraction with diluted mineral acid
  • Selective heavy metal separation by reductive precipitation
  • Specific precipitation of phosphorus at ideal ph conditions
  • Recovery of the sewage sludge bottom ash

With the demonstration plant 5 tons of phosphor was produced. The field tests made confirmed the suitability of the Leachphos product as fertiliser. Instead of using the recovered phosphor as fertiliser, the production of phosphoric acid would also be feasible.
Presently additional technical and commercial clarifications are being organised by ZAR.

* Registered Trademark and protected by patent

In case of questions please contact our head of process department:


Personal Contact

André Schöpf

dipl. Chem. Ing. ETH
Implementation / Process

Phone +41 41 925 70 27