Removing uranium and radium from a natural water

Different types of iron- or aluminium-based coagulants were used to study the influence of the key water potabilization processes of coagulation, flocculation, and decantation on the elimination of significant concentrations of uranium and radium. We first determined the physico-chemical and radiological characteristics of a natural water to use in the trials, to which we then added known activities of U-233 and Ra-226. While the efficiency of the decontamination processes was found to be independent of coagulant dose, there was a clear dependence on the pH at which the coagulation was carried out, with the optimum for the elimination of uranium being pH 6 and for radium pH 10. Uranium elimination was independent of the type of coagulant used, but the best radium elimination was with the iron-based reagents.