Study on the remediation of uranium contaminated water by indigenous bacteria in tailing pond and the mechanism of mineralization and precipitation

To address the remediation demand of uranium-contaminated water in the uranium tailings pond area, the removal mechanism of biomineralisation uranium fixation based on microbial-induced carbonate precipitation (MICP) technology was systematically explored. The mechanism of enhancing uranium removal efficiency and the synergistic uranium fixation pathway of HK-1 was elucidated using the selected indigenous Sporosarcina sp. strain (HK-1). The results showed that the biological removal rate and mineralization rate of uranium after domestication increased to 44.03 % and 58.68 %, respectively. After optimising the culture parameters using response surface methodology, the high-efficiency uranium removal effect of uranium-fixation coprecipitation products could be achieved, and the solidification stability could be enhanced through lattice substitution and encapsulation. The mineralisation kinetics analysis under uranium stress revealed that the uranium fixation efficiency of domesticated strains was further enhanced to 86.14 %, and the secondary release rate of uranium in coprecipitation products was significantly reduced. Microscopic characterization revealed the mechanism of action: 1) biosorption of functional groups of bacteria; 2) Interfacial coordination and complexation of carbonate minerals; 3) UO₂²⁺ is transformed by lattice-supported coprecipitation. Through the directional formation of uranium-calcium carbonate composite minerals, MICP technology significantly inhibits the dissolution and migration of uranium, thereby enhancing its stability.