Possible approach to cleaning 'problematic' LRW with large contents of suspended particles, oils and other organic substances

A general structural scheme for cleaning 'problematic' liquid radioactive wastes (LRW) containing a large amount of suspended particles, oils and other organic substances has been proposed. The technological scheme includes two main stages: 1) separation of suspended particles, oil product emulsions and the larger part of colloidal particles from LRW by filtration, 2) purification of radioactive waters from radionuclides by membrane-sorption to the levels of radiation safety norms applied. The filtration stage is considered as a three-step process of 'problematic' LRW treatment including: 1) 'problematic' LRW extraction from storage tanks with a robot type device intended for washing out the bottom sediment (slurry), 2) separation of suspended particles, oil product emulsions and larger part of colloidal particles from LRW by filtration through porous or gauze diaphragms of 0.1 to 10 μm pores (cells) in size, 3) concentration of separated slurry up to 100-200 g/l. Two main options of the membrane-sorption technologies, AQUA-EXPRESS and Reverse Osmosis, for LRW purification have been considered. Two possible options of porous or gauze diaphragms productivity and lifetime increase between their surface regenerations have been shown: 1) possibility of an oxidizer introduction into initial LRW, 2) possibility to rotate a filtering element (disk or cylinder type). (authors)