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Drill cuttings (DCs, Table 1), which are produced during hydrocarbon drilling operation, are rock coated with drilling fluids and hydrocarbons. DCs without adequate treatment could leave behind thousands of tons of hazardous materials, resulting in a large environmental liability. In this work, seven DCs samples were collected from Tu and Qing oilfields, and microbes inhabiting the DCs were revealed through 16S rDNA gene sequencing. The DCs from Qing oilfield showed higher microbial community abundance than those from Tu oilfield. The dominant microbes were Acinetobacter, Pseudomonas, Nesterenkonia, Trichococcus, Soehngenia, Proteiniclasticum, and Fusibacter. Most of microorganisms could produce biosurfactant which has an ability of degradation of crude oil and bioremediation. Biosynthesis and biodegradation were predicted to be the most significant metabolic pathways in all samples. This study provides a fundamental insight into the potential reuse and save the cost of conventional treatment DCs, environmental bioremediation applications of DCs through indigenous microbes produced biosurfactant and degraded ability in oil reservoirs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Rationale: Heteroatomic compounds are relatively abundant and believed to be bio‐resistant in heavy crude oils. However, few studies have focused on the biodegradation of these heteroatomic compounds. Methods: Heteroatoms, especially N1 species, in a blank crude oil and in three treated oils co‐incubated with anaerobic sulfate‐reducing bacteria, nitrate‐reducing bacteria and fermentative consortia cultures were detected using negative‐ion electrospray ionization coupled with high‐field Fourier transform ion cyclotron resonance mass spectrometry. Results: The relative abundance of N1 species in the three treated oils decreased, while the relative abundance of O2 species increased. Remarkably, the relative abundances of N1 species with low carbon number increased and those with higher carbon number decreased. Conclusions: These results revealed that the anaerobic biodegradations of heavy crude oil occurred. With direct evidences, the degradations of alkyl side chains of N1 species by the anaerobic microbes could be deduced. [ABSTRACT FROM AUTHOR]