The natural radionuclides uranium and radon can also be detected in low concentrations in natural drinking water in areas with increased natural radioactivity. While the inert gas radon (guide dose 100 Bq/l) is easily degassed and can be removed from the water by aeration (e.g. by means of an appropriately designed tank inlet), uranium (limit value 0.010 mg/l) must be removed from the water by means of technical treatment measures.
The ion exchange process has established itself as the standard procedure. The sulfate and carbonate complexes of uranium are bound and removed from the water by means of special ion-selective, strongly basic resins. Uranium removal filters are not regenerated during operation. When the filter is fully loaded, the material will be replaced and regenerated in an external system. Material exchange with transport and refilling with disinfection must be carried out without exception by competent personnel. A complete water analysis is required for the correct dimensioning of a plant. Uranium removal filters are generally designed for an operating life of around 3 years until the material is replaced.