Removal naturally occurring radionuclides from drinking water using a filter specifically designed for Drinking Water Treatment Plants

The occurrence of naturally occurring radionuclides in drinking water can pose health hazards in some populations, especially taking into account that routine procedures in Drinking Water Treatment Plants (DWTPs) are normally unable to remove them efficiently from drinking water. In fact, these procedures are practically transparent to them, and in particular to radium. In this paper, the characterization and capabilities of a patented filter designed to remove radium from drinking water with high efficiency is described. This filter is based on a sandwich structure of silica and green sand, with a natural high content manganese oxide. Both sands are authorized by Spanish authorities to be used in Drinking Water Treatment Plants. The Mn distribution in the green sand was found to be homogenous, thus providing a great number of adsorption sites for radium. Kinetic studies showed that the Ra adsorption on green sand was influenced by the content of major cations solved in the treated water, but the saturation level, about 96–99%, was not affected by it. The physico-chemical parameters of the treated water were unaltered by the filter. The efficiency of the filter for the removal of Ra remained unchanged with large water volumes passed through it, proving its potential use in DWTP. This filter was also able to remove initially the uranium content due to the presence of FeO particles in it, although it is saturated faster than radium.We wish to thank ENRESA (Empresa Nacional de Residuos Radiactivos S.A.) and CSN (Consejo de Seguridad Nuclear) for the financial support to the project entitled “Implantación de sistemas para la eliminación del contenido radioactivo natural en las aguas de consumo humano”. This work was partially made possible by the financial support granted to the LARUEX research group (FQM001).Peer Reviewe