Biotechnology

Biography

Biography: Alexy Safonov

Abstract

Liquid radioactive wastes (LRW) are multicomponent systems consisting of various macro-components like nitrate, sulfate ions, extractants, solvents, detergents and as well of microcomponents – radionuclides (U, Cs, Sr, Tc) and metals Cr, Zn, Cu etc. The aim of this work is the use of bacteria for waste denitration and purification from radionuclides and toxic metals. Here we used the microorganisms separated from extreme habitats: repositories of radioactive waste, alkaline lakes of Kulunda steppe, (salinity up to 300 g / l and pH 9 -11) and underground water, contaminated with nitrate and radionuclides. All of strain were able to reduce nitrate anions to molecular nitrogen and metals from high valence to low. We used radwastes models, based on the data of FSUE “RADON” analytical laboratory. The concentration of nitrates varied from 4 to 100 g/l, sulfates up to 2 g/l, bicarbonate HCO3- up to 10 g/l with pH 9-10. Laboratory designed biofilters with different types of cultivation (in static and flow-through conditions) were used. During the cultivation in the flow-through biofilter system the rate and degree of nitrate consumption has been significantly increased by formation of a surface biofilm on an inert carrier providing higher specific surface. Bacterial cells were able to immobilize radionuclides from the solution U (88-96%), Th (up to 90 %) Sr (50-60 %), Tc, Cs, and toxic metals Cr, V, Mo, La, cause to purification of radioactive waste.