MicroBent · Microbial activity at the Bentonite barrier in a deep geological nuclear waste repository

Management of nuclear waste is a serious worldwide environmental problem all. Deep geological repositories have been internationally proposed as the safest option for the disposal of these hazardous materials. The concept is based on a multi-barrier storage system with waste containers, surrounded by a bentonite buffer buried deeply within a stable geological formation. The bentonite formations in Almeria were characterized as a bentonite buffer reference material. However, few studies have described the influence of the microbes in the repository under in situ conditions, although its safety can be compromised not only by physical and chemical factors, but also by biogeochemical activity. Therefore, the hypothesis to be tested in this proposal is that indigenous microorganisms may play an important role for the safe disposal of nuclear waste. The main objective of this proposal is to study the microbial diversity and activity of the bentonite buffer under in situ conditions for a repository of radioactive waste. To address these points the following objectives will be carried out under in situ conditions: 1) to characterize the mineralogical and geochemical composition of the bentonite buffer 2) to determine the microbial of the incubated bentonite buffer 3) to determine the microbial activity of the incubated bentonite buffer. This proposal will extend the state-of-the-art for nuclear waste repositories by identifying active microorganisms in compacted bentonites and natural deep groundwaters and active microbial metabolic pathways. These vital questions need to be addressed to ensure the safety of the deep geological repository of nuclear waste, but also for other biotechnological uses like bioremediation of contaminated sites.