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Cheng G, Chen D, Zhang D, Li H, Du K, Zhang L. The effect of reflux ratio on sulfur disproportionation tendency in anaerobic baffled reactor with the heterotrophic combining sulfur autotrophic processes under high concentration perchlorate stress. Environ Sci Pollut Res Int 2024; 31:25929-25939. [PMID: 38488916 DOI: 10.1007/s11356-024-32835-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 03/05/2024] [Indexed: 03/17/2024]
Abstract
In a laboratory scale, an anaerobic baffled reactor (ABR) consisting of eight compartments, the heterotrophic combining sulfur autotrophic processes under different reflux ratios were constructed to achieve effective perchlorate removal and alleviate sulfur disproportionation reaction. Perchlorate was efficiently removed with effluent perchlorate concentration below 0.5 μg/L when the influent perchlorate concentration was 1030 mg/L during stages I ~ V, indicating that heterotrophic combining sulfur autotrophic perchlorate reduction processes can effectively achieve high concentration perchlorate removal. Furthermore, the 100% reflux ratio could reduce the contact time between sulfur particles and water; thus, the sulfur disproportionation reaction was inhibited. However, the inhibition effect of reflux on sulfur disproportionation was attenuated due to dilute perchlorate concentration when a reflux ratio of 150% and 200% was implemented. Meanwhile, the content of extracellular polymeric substances (EPS) in the heterotrophic unit (36.79 ~ 45.71 mg/g VSS) was higher than that in the sulfur autotrophic unit (22.19 ~ 25.77 mg/g VSS), indicating that high concentration perchlorate stress in the heterotrophic unit promoted EPS secretion. Thereinto, the PN content of sulfur autotrophic unit decreased in stage III and stage V due to decreasing perchlorate concentration in the autotrophic unit. Meanwhile, the PS content increased with increasing reflux in the autotrophic unit, which was conducive to the formation of biofilm. Furthermore, the high-throughput sequencing result showed that Proteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes were the dominant phyla and Longilinea, Diaphorobacter, Acinetobacter, and Nitrobacter were the dominant genus in ABR, which were associated with heterotrophic or autotrophic perchlorate reduction and beneficial for effective perchlorate removal. The study indicated that reflux was a reasonable strategy for alleviating sulfur disproportionation in heterotrophic combining sulfur autotrophic perchlorate removal processes.
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Affiliation(s)
- Guiyang Cheng
- Tianjin Key Laboratory of Aquatic Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Jinjing Road 26#, Tianjin, 300384, People's Republic of China
| | - Denghui Chen
- Beijing Enterprises Water Group (China) Investment Limited, Beijing, 100102, China
| | - Daohong Zhang
- Tianjin Key Laboratory of Aquatic Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Jinjing Road 26#, Tianjin, 300384, People's Republic of China.
| | - Haibo Li
- Tianjin Key Laboratory of Aquatic Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Jinjing Road 26#, Tianjin, 300384, People's Republic of China
| | - Kang Du
- China Energy Conservation and Environmental Group, Co., Ltd., Beijing, Beijing, 100082, China
| | - Lin Zhang
- Shandong Hualing Technology Engineering Group Co., Ltd., Dongying, 257000, Shandong, China
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Luo LW, Wu YH, Chen GQ, Wang HB, Wang YH, Tong X, Bai Y, Xu YQ, Zhang ZW, Ikuno N, Hu HY. Chlorine-resistant bacteria (CRB) in the reverse osmosis system for wastewater reclamation: Isolation, identification and membrane fouling mechanisms. Water Res 2022; 209:117966. [PMID: 34952485 DOI: 10.1016/j.watres.2021.117966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/30/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
Chlorine disinfection is often used as a pretreatment technology to control biofouling of reverse osmosis (RO) membranes. However, previous studies showed that biofouling of the RO system was aggravated after chlorine disinfection. Chlorine-resistant bacteria (CRB) were presumed to be closely related to the aggravation of fouling caused by chlorine disinfection. In order to analyze the membrane fouling mechanisms of CRB, 5 CRB strains were isolated from the surface of fouled RO membranes for wastewater reclamation, and 3 reference bacterial strains, Sphingopyxis soli BM1-1, Pseudomonas aeruginosa PAO1 and Escherichia coli CGMCC1.3373, were selected for comparative study. The chlorine resistance, membrane fouling potential, secretion and adhesion characteristics of these strains were evaluated. Among these isolated strains, 3 strains showed much higher chlorine resistance than PAO1 under the condition of 0.5, 2, 5 mg/L-Cl2, especially Bacillus CR19 and Bacillus CR2. Furthermore, a significant positive correlation was found between membrane fouling potential and chlorine resistance of all the strains in this study. The membrane fouling potential of the above 8 strains increased monotonically with the increase of chlorine resistance (under the condition of 0.5 mg/L-Cl2). Serious fouling caused by extracellular substances was observed in biofouling layers of the strains with high chlorine resistance, which lead to more severe flux decline. Extracellular polymeric substances (EPS) amount per cell was found to be the main factor related to the chlorine resistance as well as the fouling potential. Computational fluid dynamics (CFD) simulation was used to demonstrate the filtration resistance induced by the secretion of EPS. However, CRB with higher EPS amount may not show higher membrane adhesion potential, and thus may not be the dominant strain on the RO membranes before chlorine disinfection. These CRB with high fouling potential but low membrane adhesion potential, such as Bacillus CR19 and Bacillus CR2, may become the dominant bacteria on the membrane surface after chlorine disinfection and thus aggravate membrane fouling significantly.
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Affiliation(s)
- Li-Wei Luo
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Yin-Hu Wu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China.
| | - Gen-Qiang Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Hao-Bin Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Yun-Hong Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Xin Tong
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Yuan Bai
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Yu-Qing Xu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Zi-Wei Zhang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Nozomu Ikuno
- Kurita Water Industries Ltd., Nakano-ku, Tokyo 164-0001, Japan
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China; Research Institute for Environmental Innovation (Suzhou), Tsinghua, Suzhou, Jiangsu 215163, China
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Iswarya V, Sharma V, Chandrasekaran N, Mukherjee A. Impact of tetracycline on the toxic effects of titanium dioxide (TiO 2) nanoparticles towards the freshwater algal species, Scenedesmus obliquus. Aquat Toxicol 2017; 193:168-177. [PMID: 29096090 DOI: 10.1016/j.aquatox.2017.10.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 06/07/2023]
Abstract
Titanium dioxide nanoparticles (TiO2 NPs) are the most risk assessed nanoparticles in the aquatic environment due to their increased usage in the various sectors from electronics to consumer products. The natural aquatic system also comprises of numerous toxicants like antibiotics, whose impact on the toxicity of nanoparticles are less assessed. Hence, it is essential to determine the effect of other toxicants on the TiO2 NP toxicity. In the current study, the impact of antibiotic (tetracycline, TC) on the toxic effect of TiO2 NPs was studied on a freshwater alga, Scenedesmus obliquus. The median effective concentrations (EC50) of TiO2 NPs and TC were noted to be 136.88±2.30μM and 0.63±0.02μM, respectively. Based on the EC50 obtained, three different concentrations of TC, such as 0.34, 0.68, and 1.36μM have been selected to evaluate their effect on the toxicity of 18.75, 37.5, and 75μM of TiO2 NPs. Existence of TC provoked the growth inhibition of TiO2 NPs at their lower concentrations. In contrast, a reduction in the growth inhibition was noted as the concentrations of TC and TiO2 NPs were increased. Abbott modeling confirmed the additive and antagonistic effects noted. The stability profile of TiO2 NPs elucidated the aggregation of NPs with an increase in time. Even though a similar trend has been followed for TiO2 NPs+TC, a significant difference in the aggregation has not been observed in most cases when compared with TiO2 NPs alone. The presence of TC lowered the Ti uptake by the algal cells, which portrayed the dominance of TC in the toxic effect of TiO2 NPs to be either additive or antagonistic. The SEM images of the algal cells upon exposure to TiO2 NPs, TC, and their mixture elucidated the aggregation of algal cells, cellular deformations like compromised cell membrane, and vacuole formation, etc. In addition, the release of algal exudates was also noticed as a protective layer over the cells to counteract the stress. EPS secretion in response to TiO2 NPs along with TC is found to be in corroboration with the toxicity patterns observed.
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Affiliation(s)
- V Iswarya
- Centre for Nanobiotechnology, VIT University, Vellore, 632014, India
| | - Vineet Sharma
- Centre for Nanobiotechnology, VIT University, Vellore, 632014, India
| | - N Chandrasekaran
- Centre for Nanobiotechnology, VIT University, Vellore, 632014, India
| | - Amitava Mukherjee
- Centre for Nanobiotechnology, VIT University, Vellore, 632014, India.
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