Application of Pilot-Scale Nanofiltration for Liquid Radioactive Waste Treatment

Abstract

The objective of this work was to evaluate the applicability of pilot scale nanofiltration for the treatment of real liquid radioactive waste originating from the operation of (i) the Research Nuclear Reactor LVR-15 in the Research Centre Řež and (ii) a Nuclear Power Plant. Experiments were performed with these radioactive waste solutions with a spiral wound polymer membrane and a ceramic membrane, and they aimed to reduce the radioactive waste volume and radioactivity. The rejection of all the tested parameters (activity of 60Co and 137Cs, and concentration of total organic carbon, Fe, H3BO3, Cl-, SO42−, NO3−and NO2−) was higher with the polymer membrane than with the ceramic membrane. With the polymer membrane, the rejection of 60Co was around 100% for all the tested solutions, and the rejection of 137Cs varied between 40% and 80%. With the ceramic membrane, the rejection of 60Co was 40-100%, and the rejection of 137Cs was 20-45%. The rejection of total organic matter varied between 50% and 90% for both membranes, and the rejection of SO42− was above 93% with the polymer membrane and above 68% with the ceramic membrane. The rejection of other studied parameters was lower and strongly depended on the feed solution parameters. The obtained results indicate that the permeate could be reused for secondary technological purposes after additional polishing, while the volume of the retentate would be further reduced and treated as radioactive waste.