Correlations between microbial taxonomies and wastewater quality parameters in a full-scale petroleum refinery wastewater treatment plant

In this study, we investigated the correlations between microbial taxonomies and wastewater properties in a fullscale petroleum refinery wastewater biotreatment system, comprising one anoxic tank and two aerobic tanks. Over one hundred organic compounds, mostly aromatics, were detected in the anoxic tank influent, with dominants being cresols and anilines. While the biotreatment process effectively removed most organic components, n-alkanes remained in the effluent of the second aerobic tank. Thauera and Ignavibacterium were the dominant genera across all tanks. Betaproteobacteria substantially decreased in the second aerobic tank where the aromatic compounds were depleted. The correlation network displayed two distinct microbial clusters. Genera in cluster I were generally positively correlated with each other and tended to co-occur, while genera in cluster II were subdivided into two small groups that were negatively correlated with the other group members. Mantel test showed that pH, nitrite and n-alkanes were potential determining factors influencing the overall community assembly. This study provides valuable insights into the chemical changes and microbial taxonomy in a complex petroleum refinery wastewater treatment system, establishing a foundation for further studies on the community regulation strategies within similar biotreatment systems.