Adaptive biodegradation and mechanism study of volatile chlorinated aromatic hydrocarbons in landfill cover soil...

Landfill gases in the bioreactor zone of waste disposal sites have posed serious threats to human health and ecosystems. This work focuses on the bioreactor zone of landfill cover soil to investigate the adaptive biodegradation mechanism of volatile chlorinated aromatic hydrocarbons (CAHs). Through long-term operation of a bioreactor system, the degradation processes of various CAHs and the dynamic changes in microbial communities in the cover soil are systematically studied. The results indicate that microbial communities in the cover soil exhibit adaptive growth and metabolic characteristics in the presence of CAHs. The variations in dominant bacterial genera at different depths of the cover soil reveal the metabolic adaptability of microorganisms under different oxygen concentration conditions. In particular, the abundance changes of aerobic and anaerobic bacteria significantly influencing CAHs degradation. Correlation analysis reveals a close relationship between environmental factors such as oxygen concentration, CAHs concentration, chloride ion concentration, and the composition of microbial communities, highlighting the sensitive response of microbial communities to environmental factors. Furthermore, the study identifies inhibitory effects of high concentrations of certain CAHs on specific bacterial genera, implying the significance of complex competition and inhibition relationships during the degradation process. This study deeply elucidates the adaptive degradation mechanism of volatile chlorinated aromatic hydrocarbons by microbial communities in the cover soil, providing essential theoretical and practical guidance for pollution control in landfill sites.