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Chen Y, Yuan CJ, Xu BJ, Cao JY, Lee MY, Liu M, Wu Q, Du Y. Suppressing Organic Bromine but Promoting Bromate: Is the Ultraviolet/Ozone Process a Double-Edged Sword for the Toxicity of Wastewater to Mammalian Cells? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38872439 DOI: 10.1021/acs.est.4c00329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Brominated byproducts and toxicity generation are critical issues for ozone application to wastewater containing bromide. This study demonstrated that ultraviolet/ozone (UV/O3, 100 mJ/cm2, 1 mg-O3/mg-DOC) reduced the cytotoxicity of wastewater from 14.2 mg of pentol/L produced by ozonation to 4.3 mg of pentol/L (1 mg/L bromide, pH 7.0). The genotoxicity was also reduced from 1.65 to 0.17 μg-4-NQO/L by UV/O3. Compared with that of O3 alone, adsorbable organic bromine was reduced from 25.8 to 5.3 μg/L by UV/O3, but bromate increased from 32.9 to 71.4 μg/L. The UV/O3 process enhanced the removal of pre-existing precursors (highly unsaturated and phenolic compounds and poly aromatic hydrocarbons), while new precursors were generated, yet the combined effect of UV/O3 on precursors did not result in a significant change in toxicity. Instead, UV radiation inhibited HOBr concentration through both rapid O3 decomposition to reduce HOBr production and decomposition of the formed HOBr, thus suppressing the AOBr formation. However, the hydroxyl radical-dominated pathway in UV/O3 led to a significant increase of bromate. Considering both organic bromine and bromate, the UV/O3 process effectively controlled both cytotoxicity and genotoxicity of wastewater to mammalian cells, even though an emphasis should be also placed on managing elevated bromate. Futhermore, other end points are needed to evaluate the toxicity outcomes of the UV/O3 process.
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Affiliation(s)
- Ying Chen
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Chang-Jie Yuan
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Bao-Jun Xu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Jie-Yu Cao
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Min-Yong Lee
- Division of Chemical Research, National Institute of Environmental Research, Seogu, Incheon 22689, Republic of Korea
| | - Min Liu
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
| | - Qianyuan Wu
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Ye Du
- College of Architecture and Environment, Sichuan University, Chengdu 610000, China
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Shen Y, Luo J, Di Cesare A, Guo N, Zou S, Yang Y. Performance evaluation for the inactivation of multidrug-resistant bacteria in wastewater effluent by different disinfection technologies. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 345:123427. [PMID: 38286262 DOI: 10.1016/j.envpol.2024.123427] [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: 06/24/2023] [Revised: 12/21/2023] [Accepted: 01/21/2024] [Indexed: 01/31/2024]
Abstract
The escalating presence of antibiotic-resistant bacteria (ARB) in aquatic ecosystems underscores the critical role of wastewater treatment plants (WWTPs) in mitigating antibiotic resistance. Disinfection is the final, pivotal step in WWTPs, and it is essential to control the dissemination of ARB before water discharge. This study utilized both phenotypic analysis and transcriptome (RNA-seq) approach to investigate the efficiency and mechanisms of disinfection using chlorination, ultraviolet (UV), and peracetic acid (PAA) on multidrug-resistant bacteria (MRB). Our results demonstrated that the use of 100 mg min L-1 of chlorine, 8.19 mJ cm-2 of UV irradiation or 50 min mg L-1 of PAA significantly reduced the abundance of MRB. Intriguingly, RNA-seq clarified distinct mechanisms of chlorination and UV disinfection. UV radiation triggered the SOS response to cope with DNA damage, induced the expression of multi-drug resistance genes by increasing the expression of efflux pump transporters. UV radiation also promoted the absorption of iron through chelation and transportation to participate in various cell life processes. Chlorination, on the other hand, significantly up-regulated osmotic response elements, including the synthesis of glycine betaine, iron-sulfur clusters, and related transporters. Both chlorination and UV significantly down-regulated key metabolic pathways (P < 0.05), inhibiting the process of amino acid synthesis and energy metabolism. Imbalance in energy homeostasis was the most important factor leading to cytotoxicity. These results provide useful insights into optimizing the wastewater disinfection process in order to prevent the dissemination of ARB in aquatic environment.
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Affiliation(s)
- Yijing Shen
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, 519082, China
| | - Jieling Luo
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China
| | - Andrea Di Cesare
- National Research Council of Italy - Water Research Institute (CNR-IRSA) Molecular Ecology Group (MEG), Verbania, 28922, Italy
| | - Nairong Guo
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, 519082, China
| | - Shichun Zou
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, 519082, China
| | - Ying Yang
- School of Marine Sciences, Sun Yat-sen University, Zhuhai, 519082, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519000, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, 519082, China.
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