Today, there are already a variety of very different approaches to the recovery of phosphorus from wastewater, sludge and ashes. These approaches differ by the origin of the used matter (wastewater, sludge liquor, fermented or non-fermented sludge ash) and the process (precipitation, wet chemical extraction, and thermal treatment).
SARTORIUS, C. HORN, J. von TETTENBORN, F. (2011): Phosphorus Recovery from Wastewater – State-of-the-Art and Future Potential. Karlsruhe: Fraunhofer Institute for Systems and Innovation Research URL [Accessed: 10.06.2019]