AWWA WKICO66052

Uranium is naturally present in the environment. Where present in potable water, 80% of our total daily intake of uranium can be derived from drinking water. Currently no European Union (EU) standards exist for uranium in drinking water. Recommendations have been made by the World Health Organization (WHO) for a more rigorous reference level for uranium in drinking water supplies; there is the possibility that this will be incorporated in United Kingdom regulations in the long term. Severn Trent Water (STW) in the United Kingdom reviewed and identified water sources at risk. STW commissioned a study to identify suitable adsorbents or ion exchange resins for removal of uranium. This identified that a strong base anion exchange resin exhibited the greatest capacity for uranium removal. Trials using strong base anion exchange resins were subsequently carried out at a groundwater source containing uranium levels between 13 and 19 µg/l. An initial treatment run of 16,000 bed volumes (BV), showed no uranium breakthrough, the resin was regenerated with 5% sodium chloride. A second run achieved treatment of 265,000 BV without any significant breakthrough of uranium. After regeneration, the performance was monitored over a period of 11 months. The regenerated resin again performed exceptionally well with minimal impact on the resin's capacity to remove uranium. After 300,000 bed volumes the uranium level in the treated groundwater was <3 µg/l. Successful uranium removal from drinking water has been established; the best practice for operating a full scale plant is currently under review. STW's focus is on waste disposal; adsorbed uranium can be disposed of in an aqueous form either frequently or infrequently depending on regeneration intervals, or as a solid with no regeneration taking place. Includes tables, figures.