Performance and microbial diversity of a full-scale oilfield wastewater treatment plant

摘要

In this study, the performance and microbial diversity of an oilfield wastewater treatment plant with an integrated anaerobic baffled reactor (ABR) and sequencing batch reactor (SBR) system were investigated. The analysis showed that the range of influent chemical oxygen demand and oil concentration was 215-731 and 9-52 mg/L, while the effluent concentration decreased to 30-87 and 2-8 mg/L after treatment, giving mean removal efficiencies of 88.5% and 85.0%, respectively. The removal efficiency of other indices in the wastewater (S2-, total suspended solids, and NH3-N) reached 99.0%, 94.0%, and 80.1%, respectively. The microbial community analysis showed that the dominant bacterial and fungal species identified in the systems are halotolerant, suggesting that the process performances stated in this study were made possible by the adaptation of halotolerant microorganisms. Moreover, the results indicated that bacterial genera including Marinobacterium, Marinobacter, Thiomicrospira, Methylophaga, and Pseudomonas were likely to be actively involved in the decomposition processes of oil pollutants in the system. Furthermore, fungal communities were evenly distributed, with Ascomycota, Basidiomycota, and Zygomycota as the main phyla. Among them, Alternaria, Meyerozyma, Cryptococcus, Aspergillus, Candida, Stachybotrys, Fusarium, Blastobotrys, Mortierella, Rasamsonia, and Geminibasidium were abundant in the ABR and SBR systems, and may involve in the degradation process.