Removal of tetracycline in nitrification membrane bioreactors with different ammonia loading rates: Performance, metabolic pathway, and key contributors

Huaihao Xu; Yuepeng Deng; Mingji Li; Kaoming Zhang; Jie Zou; Yunhua Yang; Peng Shi; Yiping Feng; Chun Hu; Zhu Wang

doi:10.1016/j.envpol.2023.121922

Removal of tetracycline in nitrification membrane bioreactors with different ammonia loading rates: Performance, metabolic pathway, and key contributors

Environ Pollut. 2023 Sep 1:332:121922. doi: 10.1016/j.envpol.2023.121922. Epub 2023 May 29.

Authors

Huaihao Xu¹, Yuepeng Deng¹, Mingji Li¹, Kaoming Zhang¹, Jie Zou¹, Yunhua Yang¹, Peng Shi², Yiping Feng³, Chun Hu¹, Zhu Wang⁴

Affiliations

¹ Institute of Environmental Research at Greater Bay/ Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China.
² State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
³ Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.
⁴ Institute of Environmental Research at Greater Bay/ Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou, 510006, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China. Electronic address: wangzhu@gzhu.edu.cn.

PMID: 37257809
DOI: 10.1016/j.envpol.2023.121922

Abstract

Membrane bioreactors (MBRs) have been widely applied for the treatment of wastewater that contains high concentrations of both ammonium and antibiotics. Nonetheless, information about tetracycline (TC) removal in nitrification MBRs with high ammonium loading rates (ALRs) is still very limited. Herein, the fate of TC at four different concentrations of 1, 5, 20, and 50 mg/L in three parallel lab-scale nitrification MBRs with different ALRs (named AN50, AN500, and AN1000) were investigated in this study. Excellent nitrification performance and high TC removal efficiency (90.46%) were achieved in AN1000 at influent TC concentration of 50 mg/L. Higher ALRs promoted the removal of TC at lower influent TC concentration (≤5 mg/L), while no significant difference was observed in TC removal efficiencies among different ALRs MBRs at higher influent TC concentration (≥20 mg/L), implying that the heterotrophic degradation could be strengthened after long-term exposure to high concentration of TC. Batch tests demonstrated that adsorption and biodegradation were the primary TC removal routes by nitrification sludge, of which both autotrophic ammonia oxidizers and heterotrophic microorganisms played an important role in the biodegradation of TC. FT-IR spectroscopy confirmed that amide groups on the sludge biomass contributed to the adsorption of TC. Mass balance analyses indicated that biodegradation (63.4-88.6% for AN50, 74.5-88.4% for AN500 and 74.4-91.4% for AN1000) was the major mechanism responsible for the removal of TC in nitrification MBRs, and its contribution increased with influent TC concentration, while only 1.1%-15.0% of TC removal was due to biosorption. TC was progressively degraded to small molecules and the presence of TC had no notable effect on membrane permeability. These jointly confirmed TC could be effectively removed via initial adsorption and subsequent biodegradation, while biodegradation was the primary mechanism in this study.

Keywords: Ammonia loading rate; Biodegradation; Cometabolism; MBR; Tetracycline.

MeSH terms

Ammonia* / metabolism
Ammonium Compounds*
Anti-Bacterial Agents
Bioreactors
Metabolic Networks and Pathways
Nitrification
Sewage / chemistry
Spectroscopy, Fourier Transform Infrared
Tetracycline
Waste Disposal, Fluid / methods

Substances

Ammonia
Sewage
Anti-Bacterial Agents
Tetracycline
Ammonium Compounds