Process for purifying aqueous solutions polluted by nitrate ions.

摘要

Process for the purification of aqueous solutions contaminated with nitrate ions. This process is characterised in that it consists in precipitating double or mixed hydrated calcium nitroaluminates, such as especially calcium mononitroaluminate hydrate, by addition of at least one agent introducing the element aluminium and at least one agent introducing the element calcium into the solutions to be treated, the overall molar ratio of the element aluminium to nitrate, Al/NO3, being higher than 1, the overall molar ratio of calcium to nitrate, Ca/NO3, being greater than 2, and in that the precipitation reaction is performed with stirring and at basic pH, preferably higher than 10.5. The process according to the invention is intended especially for the treatment of polluted waters such as domestic sewage and industrial effluents and for the treatment of liquid manure.