Assessing the Efficiency and Mechanisms of Chlorobenzene Degradation Using an Immobilized Bacterial Consortium Supplemented with Micron Zerovalent Iron and Biomass

Abstract

Chlorobenzene (CB) is a widely utilized organic solvent that poses a significant environmental threat owing to its chemical stability, toxicity, persistence, and bioaccumulation. Especially, actual chlorobenzene-contaminated sites (CBs) are characterized by multiple co-occurring chlorinated compounds, highlighting the urgent need for green and efficient remediation technologies. In this study, a one-year remediation experiment was conducted using groundwater from an actual CB-contaminated site as the simulated water source. The experiment employed a reactive column system filled with micron zerovalent iron (mZVI) and biomass (wheat bran). The degradation efficiency and underlying mechanisms of CB were investigated, revealing that microbial immobilization was achieved within 3 months and a functional community that utilizes CB as a carbon source was established within 6 months. The degradation efficiency of CB by the immobilized bacterial consortium remained above 99% starting from day 181. Additionally, mZVI transformed into goethite, siderite, and hematite in its final forms. Notably, Stutzerimonas, Alcaligenes, and Brevundimonas were identified as key genera in the remediation of CBs, particularly through their roles in the benzoate degradation pathway. This research confirmed the feasibility of using an immobilized bacterial consortium utilizing mZVI and wheat bran to address organic pollution at CBs and offered theoretical support for this approach.