Comparison of bacterial communities and antibiotic resistance genes in oxidation ditches and membrane bioreactors

Lifang Luo,Lixin Yang,Hailong Li,Hui Ma,Weiguo Liu,Yinguang Chen,Junqin Yao,Ziteng Liu,Ming Liang

doi:10.1038/s41598-021-88335-z

Lifang Luo, Lixin Yang + Show 7 more

Open Access

https://doi.org/10.1038/s41598-021-88335-z

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Journal: Scientific Reports	Publication Date: Apr 26, 2021
Citations: 12	License type: open-access

Affiliation: Xinjiang University, Tongji University

Abstract

Oxidation ditches (ODs) and membrane bioreactors (MBRs) are widely used in wastewater treatment plants (WWTPs) with bacteria and antibiotic resistance genes (ARGs) running through the whole system. In this study, metagenomic sequencing was used to compare the bacterial communities and ARGs in the OD and MBR systems, which received the same influent in a WWTP located in Xinjiang, China. The results showed that the removal efficiency of pollutants by the MBR process was better than that by the OD process. The composition and the relative abundance of bacteria in activated sludge were similar at the phylum and genus levels and were not affected by process type. Multidrug, fluoroquinolones and peptides were the main ARG types for the two processes, with macB being the main ARG subtype, and the relative abundance of ARG subtypes in MBR effluent was much higher than that in the OD effluent. The mobile genetic elements (MGEs) in the activated sludge were mainly transposons (tnpA) and insertion sequences (ISs; IS91). These results provide a theoretical basis for process selection and controlling the spread of ARGs.

Highlights

Oxidation ditches (ODs) and membrane bioreactors (MBRs) are widely used in wastewater treatment plants (WWTPs) with bacteria and antibiotic resistance genes (ARGs) running through the whole system
The secondary sedimentation tank following the OD relies on gravity sedimentation, while the MBR relies on filtration and interception via the m embrane[1]
Differences in the systems resulted in higher removal rates of N H4+-N and total nitrogen (TN) in the OD than in the MBR and higher removal rates of chemical oxygen demand (COD), B OD5, SS, and total phosphorus (TP) in the MBR than in the OD

Summary

Introduction

Oxidation ditches (ODs) and membrane bioreactors (MBRs) are widely used in wastewater treatment plants (WWTPs) with bacteria and antibiotic resistance genes (ARGs) running through the whole system. The secondary sedimentation tank following the OD relies on gravity sedimentation, while the MBR relies on filtration and interception via the m embrane[1] These systems have unique artificial microbial ecosystems that characteristically harbor high microbial diversity and a large number of microorganisms, especially bacteria carrying various types of antibiotic resistance genes (ARGs), which can drive changes in ARGs2,3. Zoogloea[1], Flavobacterium[7], Thauera[1,7], Comamonas[7], Haliscomenobacter[12] and Rhodobacter[12] are considered dominant, and the PAOs Tetrasphaera and Accumulibacter are frequently detected in M BRs13,14 These abundant bacterial genera are widely distributed in the treatment system and are responsible for effectively removing nitrogen, phosphorus and other pollutants, as well as ensuring stable effluent quality[7,12,13]. This study offers insight for further controlling the prevalence of ARGs

Methods

Results

Conclusion