MICROBIOLOGICAL APPROACH TO PURIFICATION OF LIQUID RADWASTES

摘要

Many liquid radwastes are low-level and characterized by diverse chemical composition. Aside from radionuclides with total activity to 10 kBq/cm~3, they contain macro quantities of nitrate and sulfate sodium salts with concentration 10 g/dm~3 tributyl phosphate, acetates and oxalates, petroleum products (kerosene, synthine, mineral vacuum and transformer oils), deactivating solutions and complexones (ethylenediaminetetraacetic acid) [1]. In the main concept for storing radwastes in the form of cement matrices in dry repositories, the presence of nitrate ions and organic components, first and foremost, petroleum products, intensifies the biogenic destruction of concrete owing to the formation of gases and organic acids [2]. Nitrate salts and organic substances lower the purification factor of membrane and ion-exchange technologies. It should be noted that for deep disposal of liquid wastes in collector formations the toxicity of nitrate salts is more than 100 times higher than the maximum admissible values and the mobility of the salts in underground ecosystems is difficult to control.