Radionuclides in Drinking Water
Treatment Residual Characteristics
All treatment technologies for radionuclides produce one or more forms of liquid or solid residuals (waste). Liquid residuals include brine, backwash water, reject water, acid neutralization water, caustic regenerant, and rinse water. The most common methods for liquid residual disposal is discharge to a sewer. Some water systems may also be able to dispose of liquid residuals by direct discharge to a water body, in underground injection wells, in on-site wastewater treatment systems, or hauling the liquid residuals to a wastewater treatment plant. If liquid residual disposal options are limited or unavailable, there are treatment units that do not generate significant quantities of liquid waste.
Solid residuals include wastes such as exhausted, aged/ineffective filter media, and sludge from processes like lime softening, ion exchange, pre-formed hydrous manganese oxide filtration, and coagulation/filtration. Solid residuals are generally disposed of in landfills (or special facilities, if the concentrations of radionuclides are too high).
Disposal options for liquid and solid residuals may be influenced by: the amount and concentration of contaminants in solid residuals; federal, state, and local regulations; the system’s location; transportation options; and cost. The types of waste produced by the common treatment technologies for radionuclides are shown in the following table.
For general information on types of waste and related considerations, see: