ИСТИНА

Permeable reactive barriers (PRB) enable physical, chemical or biological in situ treatment of contaminated groundwater by bringing it into contact with reactive materials. The reactive material is inserted underground in a natural aquifer and intercepts the pollution plume as it is carried along within the aquifer, and thus the contaminants are treated without either wholesale soil excavation or water pumping. This cost-effective clean-up technology has much less impact on the environment than other methods and is generally more economical over the long term as compared to other methods. In this study sorption characteristics of different materials that can be used for creation of complex multi-layer PRB were specified. For apatite, vermiculite, lightweight expanded clay aggregate (LECA), wood sawdust, perlite, natural zeolite (TREYD) and shungite sorption coefficients (Kd) for 137Cs, 90Sr, 238U, 239Pu, 241Am, 99Tc and stable Cr(VI) were obtained. Speciations of these radionuclides on materials were investigated using the method of sequential extraction. Since one component of complex multi-layer PRB is denitrifying bacteria immobilized on the carrier, microbiological influence on barrier materials should be estimated. Variation of Kd and changes in speciation of sorbed radionuclides after microbiological treatment were analyzed.