Application of Microporous Materials for the Recovery of Nutrients From Wastewaters

The RIM-NUT® process is based on ion-exchange precipitation operations for the abatement of the eutrophication potential present in biologically oxidised municipal, zootechnical and industrial wastewaters. A natural zeolite (clinoptilolite) and a commercial macroporous strong-base anion exchanger selectively remove nutrient species (i.e., NH₄+; H₂PO₄=/HPO₄), which are quantitatively precipitated and recovered in the form of a premium-quality, slow-release fertiliser (MgNH₄PO₄6H₂O) from the exchangers spent regeneration eluates. Demonstration campaigns carried out in Italy and the United States on a 240 m3/d mobile plant proved the technical feasibility of the process whose economical proficiency must still be assessed.