Elucidate microbial characteristics in a full-scale treatment plant for offshore oil produced wastewater

Oil-produced wastewater treatment plants, especially those involving biological treatment processes, harbor rich and diverse microbes. However, knowledge of microbial ecology and microbial interactions determining the efficiency of plants for oil-produced wastewater is limited. Here, we performed 16S rDNA amplicon sequencing to elucidate the microbial composition and potential microbial functions in a full-scale well-worked offshore oil-produced wastewater treatment plant. Results showed that microbes that inhabited the plant were diverse and originated from oil and marine associated environments. The upstream physical and chemical treatments resulted in low microbial diversity. Organic pollutants were digested in the anaerobic baffled reactor (ABR) dominantly through fermentation combined with sulfur compounds respiration. Three aerobic parallel reactors (APRs) harbored different microbial groups that performed similar potential functions, such as hydrocarbon degradation, acidogenesis, photosynthetic assimilation, and nitrogen removal. Microbial characteristics were important to the performance of oil-produced wastewater treatment plants with biological processes.

Automated summary

Oil-produced wastewater treatment plants, particularly those using biological processes, host a diverse range of microbes originating from oil and marine environments. Upstream treatments resulted in lower microbial diversity, while organic pollutants were mainly digested through fermentation and sulfur compounds respiration in the anaerobic baffled reactor (ABR). Characteristics of different microbial groups in aerobic parallel reactors (APRs) were important for functions like hydrocarbon degradation, acidogenesis, photosynthetic assimilation, and nitrogen removal in these plants.