Biogenic sulfidation-mediated de-passivation and reactivation of zero-valent iron: Synergism of sulfate-reducing bacteria and Shewanella towards trichloroethylene degradation.

Biogenic sulfidated zero-valent iron systems with SRB or Shewanella oneidensis MR-1 degraded trichloroethylene at ~95.7–96.2%, with a synergistic SRB–Shewanella setup sustaining 95.2–98.8% under oligotrophic conditions.

• Why it matters: Surface passivation limits ZVI for groundwater remediation, and while biogenic sulfidation can help, prior work has largely overlooked multi-strain synergism between different bacteria.
• What they did: The study built BS-ZVI systems using SRB (BS-ZVI SRB) and Shewanella oneidensis MR-1 (BS-ZVI MR-1), then tested a combined “SRB-Shewanella” system for TCE degradation and related sulfidation, passivation, and activity under oligotrophic conditions (COD = 45.7–47.3 mg/L).
• The result: BS-ZVI SRB and BS-ZVI MR-1 degraded 95.7% and 96.2% of TCE (0.43 d⁻¹ and 0.45 d⁻¹), while the combined system maintained 95.2–98.8% degradation efficiency and showed improved carbon-source utilization and enzymatic activity.

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