Utilizing natural reservoir water for cultivation of Sporosarcina pasteurii in seepage control and reinforcement of earth-rock dams: Feasibility, mechanisms, and field verification

Seepage is a prevalent defect in earth-rock dams, typically mitigated through methods such as curtain grouting. However, conventional curtain grouting depends on pressurized injection, where low pressure often results in insufficient grout penetration, while excessive pressure can fracture the dam body, leading to leakage and reduced efficiency. Compared to traditional grouting, the microbially induced calcium carbonate precipitation (MICP) technique provides significant advantages, including a distinctive cementation mechanism and low slurry viscosity, enabling both pressurized and unpressurized applications. However, the dependence on distilled water for culturing Sporosarcina pasteurii ( S. pasteurii ) considerably elevates operational costs, limiting large-scale field implementation. This study introduces and validates an innovative approach utilizing natural reservoir water as a substitute for distilled water to culture S. pasteurii for seepage control and reinforcement of earth-rock dams. Laboratory experiments systematically examine the effects of key water quality parameters ( C a 2 + , Mg 2 + , turbidity, and dissolved organic carbon) on bacterial growth, urease activity, and CaC O 3 precipitation efficiency. The results indicated that moderate ultraviolet (UV) sterilization (≥30 min) optimizes the culture environment, while the natural components present in reservoir water, such as suspended particles and ions, enhance urease activity and CaC O 3 precipitation efficiency. A three-step field-scale cultivation method is developed and successfully implemented at the Anmiaoqian Reservoir. Following MICP treatment, the permeability coefficient of the dam body decreases by nearly two orders of magnitude, demonstrating an environmentally friendly and effective alternative for seepage reinforcement in earth-rock dams. • Reservoir water can substitute distilled water for culturing S. pasteurii in MICP. • Key parameters (Ca 2+ /Mg 2+ , turbidity, DOC) affect urease activity & CaCO 3 efficiency. • UV sterilization (≥30 min) optimizes the culture environment for bacterial growth. • A three-step field cultivation method enables on-site S. pasteurii culture. • Field MICP offers an eco-friendly solution, reducing dam permeability by two orders.