In-situ bioaugmentation of uranium-contaminated groundwater using Desulfovibrio vulgaris UR1: Mechanistic insights, laboratory validation, and field performance.

While Desulfovibrio vulgaris UR1 demonstrates efficient U(VI) reduction under anaerobic conditions, its application has remained largely confined to laboratory-scale investigations. To address this limitation, this study integrates laboratory mechanistic analysis with field-scale bioaugmentation, bridging microscopic insights with macroscopic validation for the remediation of U(VI)-contaminated aquifers. Batch and simulated groundwater experiments demonstrated that quartz sand served as a matrix to promote biofilm growth and EPS secretion, which enhanced U(VI) reduction efficiency by ∼40 % and increased the UO2 (U(IV)) product proportion by 14.05 %. Bioaugmentation experiments established Desulfovibrio-dominated microbial consortia with stable effluent U(VI) concentrations around 10 μM and maintained efficient operation for over 30 days even without external carbon input. Field pilot-scale experiments achieved a U(VI) removal rate of over 90 % within 3 days and maintained a stable state for over 60 days. This study provides a promising strategy for rapid in-situ uranium remediation and supports the practical advancement of bioaugmentation technologies for uranium-contaminated groundwater.