A COMPREHENSIVE STUDY ON MICROBIAL REDUCTIVE DEHALOGENATION IN SEWAGE SLUDGE ​

Abstract

Organohalides are massively used for various applications, leading to their prevalent contamination in all ecosystems. Particularly, wastewater treatment plants (WWTPs) become an emerging sink and source of organohalide pollutants. However, the potential for sewage sludge microbiota to degrade these pollutants remains underexplored. This study worked on: 1) comprehensively evaluating dehalogenation activity of organohalide pollutants by sewage sludge microbiota, and identifying the functional bacteria and genes; 2) elucidating the survival mechanisms of anaerobic organohalide-respiring bacteria (OHRB) in sewage sludge under oxygen stress and resilience of associated microbial communities; 3) developing efficient bioremediation strategies to remediate organohalide-contaminated environments. Results demonstrated global prevalence of OHRB in WWTPs, which were resilient to oxygen stress to dehalogenate diverse organohalide pollutants. Sewage sludge amendment and bioaugmentation with Dehalococcoides were also proven effective in remediating persistent organohalide-polluted environments. The findings contribute to understanding the niches of OHRB and bioremediation of organohalide pollutants.