Process for the recovery of phosphorus

摘要

The invention relates to a method for the recovery of phosphorus in sewage treatment plants from sludge, the sludge being pre-acidified under anaerobic process conditions and then the pH value is raised to a pH value 7 by adding at least one alkaline calcium-containing chemical, brushite crystals through Calcium ions of the chemical are formed and precipitated and deposited brushite crystals are removed and then the phosphorus-reduced sludge is fed to digestion.