The Q&A session for this topic is Q&A 2: Emerging Contaminants and Radionuclide Occurrence, Treatment, and Media Disposal.
Uranium is a naturally occurring radioactive contaminant of drinking water, and it's presence is widespread throughout the Unites States. Currently uranium is regulated on the basis of its toxicity to the kidney, and the USEPA MCL for uranium in drinking water is 30 micrograms/L, which is equivalent to 45 picoCuries/L of alpha particle radioactivity. Anion exchange with chloride-form strong-base anion (SBA) resins is an effective means of removing uranium from drinking water, because, in the pH range of 6.5 -9, U is present as a negatively charged carbonate complex. This anionic complex has an extremely high affinity for SBA resins, and run lengths far exceeding 100,000 bed volumes can be attained. However, run lengths in the range of 20,000 to 50,000 BV are recommended so as to avoid excessive radium concentration on the resin. Regeneration with salt (NaCl) is effective, and the higher the salt concentration the better. Generally, spent brine disposal to a sanitary sewer is allowed, but will be regulated by the state. Adding SBA resin to a softener is also an effective way of removing hardness, radium and uranium from drinking water and this will be described.