Metagenomic insights into the effects of benzyl dodecyl dimethyl ammonium bromide (BDAB) shock on bacteria-driven nitrogen removal in a moving-bed biofilm reactor (MBBR).
CHEMOSPHERE 2023;
320:138098. [PMID:
36764616 DOI:
10.1016/j.chemosphere.2023.138098]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 01/14/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
The use of disinfectants made from quaternary ammonium compounds (QACs) has greatly increased since the outbreak of SARS-CoV-2. However, the effect of QACs on wastewater treatment performance is still unclear. In this study, a commonly used QAC, i.e., benzyl dodecyl dimethyl ammonium bromide (BDAB), was added to a moving-bed biofilm reactor (MBBR) to investigate BDAB's effect on nutrient removal. When the BDAB concentration was increased to 50 mg L-1, the ammonia removal efficiency (ARE) greatly decreased, as did the nitrate production rate constants (NPR). This inhibition was partly recovered by decreasing the BDAB concentration to 30 mg L-1. Metagenomic sequencing revealed the functional genera present during different stages of the control (Rc) and BDAB-added reactors (Re). The enriched genera (Rudaea, Nitrosospira, Sphingomonas, and Rhodanobacter) in Rc mainly related to the nitrogen metabolism, while the enriched genera in Re was BDAB-concentration dependent. Functional genes analysis suggested that a lack of ammonia oxidase-encoding genes (amoABC) may have caused a decrease in ARE in Re, while the efflux pump-encoding genes emrE, mdfA, and oprM and a gene encoding BAC oxygenase (oxyBAC) were responsible for BDAB resistance. The increase in the total abundance of antibiotic resistance genes (ARGs) in Re revealed a potential risk arising from BDAB. Overall, this study revealed the potential effect and ecological risks of BDAB introduction in WWTPs.
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