Removing phosphate and organic phosphorus from waste water - by pptn. with alkaline stabilised alumina soln. obtd. by dissolving pptd. aluminium oxide or hydroxide in soln. of alkali

摘要

Phosphates and organically combined P are removed from waste water and feed water by pptn. with an alkaline stabilised Al2O3 soln. with molar ratio of Na2O:Al2O3 of 1.5-5.0. The novelty is that the Al2O3 soln. is a fluid obtd. by dissolving pptd. Al (hydr)oxide in solns. of alkalis. The alkali stabilised soln. pref. has molar ratio of alkali oxide: Al2O3 of 1.5-3.5 (2:1), and is obtd. by inverting a water-in-oil emulsion of Al (hydr)oxide in water, or by dissolving an Al (hydr)oxide-alkali carbonate melt. USE/ADVANTAGE - The treated water is not contaminated with metal cpds.; heavy metals, e.g., Cd, Hg, Pb,Cr, Ni and Cu are eliminated with P. The compsn. of the precipitant can be better adjusted to partic. purification situations. The process can be used on the large scale. The process can be integrated with recovery of drinking water from river water (claimed).