Design and optimization of a zeolite ion exchange system for treatment of radioactive wastes

A Liquid Waste Treatment System (LWTS) has been developed to treat the variety of low level radioactive waste streams being generated from the decontamination and decommissioning of the former nuclear fuel reprocessing plant at West Valley, New York. The system uses a non-regenerative zeolite ion exchange process to remove and concentrate the radioactive contaminants (i.e., cesium and strontium) from these waste streams. To effectively process the waste streams of interest, a zeolite mixture has been identified as the media of choice. Using 2.5 cm diameter laboratory columns, testing has been conducted on this mixture to identify and optimize the critical parameters involved in the successful design and operation of this zeolite system. Areas examined included bed preparation requirements, the effect of various process conditions, and system scale-up. Proper bed preparation (e.g., fines and air removal) was found to be particularly important to the successful operation of the system. The required backwash flow rates and durations were determined. The effects of waste solution chemistry and residence time on the zeolite performance were also examined