Biodegradation time series characteristics and metabolic fate of different aromatic compounds in the biochemical treatment process of coal chemical wastewater.

In this study, the biochemical treatment system of coal chemical wastewater (CCW) was constructed to degrade aromatic compounds. The biodegradation time series characteristics of 8 benzene series (BTEX), 6 phenols, 10 polycyclic aromatic hydrocarbons (PAHs), and 3 nitrogen heterocyclic compounds (NHCs) were detected. The aim was to clarify the storage characteristics and dynamic transformation in water, EPS, and cells of these aromatic compounds. The results showed that BTEX and NHCs were more easily degraded than PAHs and phenols. Furthermore, aromatic compounds were initially adsorbed into EPS from water by microorganisms. Then, some were degraded, and others were transferred into the cell. Finally, they were completely degraded. The percentage of surplus content with them in EPS and cells were PAHs > phenols > NHCs = BTEX. The study could lay a theoretical foundation for the regulation and harmless treatment of the CCW in the stable operation of the biochemical treatment system.