CATALYSIS LETTERS
·
2024
·
IF 2.3
Meng Jiayi,Mo Hengliang,Li Tianyu,Liu Manman,Chen Yili,Li Suoding,Wan Pingyu,Lv Long,Yang Hengyu,Zhao Wenfang,Wang Luocong
Residual chlorine has a bactericidal effect, but it may react with natural organic matter in water to produce harmful substances. In this work, we report an efficient residual chlorine removal filter with activated carbon fiber (ACF) as adsorption carrier and CuO as residual chlorine degradation catalyst. Experimental results show that CuO has high catalytic efficiency and no attenuation of catalytic performance in 2924 h. The CuO is loaded on the surface of ACF by dipping-calcinating method. When the loading rate is 1.5%, the CuO distribution is uniform without defects and agglomeration. Continuous-flow experiment result shows that 1.5%-CuO/ACF filter can treat water amount 2.2 times as long as that for single ACF filter (residual chlorine concentration < 0.1 mg/L). Weak acidity and rising temperature can improve the reaction activity and increase the degradation amount of residual chlorine. The composite filter has excellent adsorption performance for Cu 2+ , showing the Cu 2+ concentration in the produced water is less than 0.1 mg/L after filter treatment, which is in line with the National Drinking Water Standards, and in agreement with the Standard for Safety Assessment of Water Transmission and Distribution Equipment and Protective Materials for Drinking Water (GB/T17219-1998) of Immersion Experiment, indicating that 1.5%-CuO/ACF filter has good stability and safety. Graphical Abstract
研究领域:
环境科学
·
材料科学
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产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2016
·
IF 1.272
Xunchao Li,Cong Li,Mingda Bayier,Taotao Zhao,Tuqiao Zhang,Xinbo Chen,Xinwei Mao
Residual chlorine decay and trihalomethanes (THM) formation of desalinated seawater by ultrafiltration (UF) and nanofiltration (NF) membranes in a pilot-scale water distribution system (DWDS) were investigated. Three-dimensional fluorescent features of two source waters including NF permeate and municipal water were studied. Sixteen groups of data-sets were obtained to explore the effects of initial chlorine concentration (ICC), dissolved organic carbon (DOC), and temperature on chlorine decay and THM formation in laboratory conditions and pilot-scale DWDS, respectively. A first-order model was applied to evaluate the chlorine decay of desalinated seawater and a new model combining ICC, DOC concentration, and temperature was obtained to determine the first-order decay coefficient. Other seven models describing the kinetics of chlorine decay were also applied and compared in this study. Total trihalomethanes (TTHM) formation kinetics was studied and first-order model was suggested to describe this formation. The relationship between TTHM formation and chlorine demand was demonstrated and the results showed that second-order polynomial model better described the relationship.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Jingyi Zhang,Zuxin Xu,Wenhai Chu,Liping Ma,Huan He,Wei Jin,Chao Fang
The severely low influent chemical oxygen demand (COD) concentration at wastewater treatment plants (WWTPs) has become a critical issue. A key factor is the excessive biodegradation of organic matter by microbial communities within sewer systems. Intense disinfection commonly adopted for medical wastewater leads to abundant residual chlorine entering sewers, likely causing significant changes in microbial communities and sewage quality in sewers, yet our understanding is limited. Through long-term sewer simulation batch tests, this study revealed the response mechanism of microbial communities to residual chlorine and its impact on organic matter concentration in sewage. Under residual chlorine stress, microbial community structure rapidly changed, and more complex microbial interactions were observed. Besides, pathways related to stress response such as two-component system were significantly enriched; pathways related to energy metabolism (such as carbon fixation in prokaryotes and citrate cycle) in microbial communities were inhibited, and carbon metabolism shifted from the Embden-Meyerhof pathway to the pentose phosphate pathway to enhance cellular reducing power, reduce oxidative stress, and consequently decrease organic matter degradation. Therefore, compared to sewers with normal disinfection, concentrations of COD and dissolved organic carbon in sewage under chlorine stress increased by 12.6 % and 7.4 %, respectively. Besides, the decay and transformation of residual chlorine in sewers were explored. These findings suggest a new approach to medical wastewater discharge management: placing the medical wastewater outlet at the upstream in sewer systems, which ensures that residual chlorine consumption reaches maximum during long-distance transportation, mitigating its harmful effects on WWTPs, and increases the influent organic matter concentration, thereby reducing the need for additional carbon sources.
研究领域:
环境工程
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微生物学
·
水处理
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Jianeng Xu,Conghui Huang,Xiaoyang Shi,Shengkun Dong,Baoling Yuan,Thanh H. Nguyen
PVC pipe loops were constructed to simulate household premise plumbing. These pipe loops were exposed to water treated by physical processes at three water treatment plants in Xiamen, China from August 2016 to June 2017. After the biofilms were allowed to develop inside the pipes, these pipes were deconstructed and exposed to organic-free chlorine solution buffered at pH 6.8 ± 0.2 for 48 h. The decay of chlorine by these biofilms was higher than by the effluent waters that were used to grow the biofilms. A chlorine consumption mass balance model elucidated the role of both the diffusion of chlorine into the biofilm and the reaction of chlorine with the biofilm matrix. Comparable concentrations of trihalomethanes were quantified from the reaction between chlorine and source water organic matters, and chlorine and the biofilm, further emphasizing the role of biofilms in the safety of disinfected drinking water. These findings imply that when chlorine is used in the drinking water distribution system, the ubiquitous presence of biofilms may cause the depletion of chlorine and the formation of non-negligible levels of toxic disinfection byproducts.
研究领域:
环境科学
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公共卫生
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水处理工程
✓ 已验证
DOI
PubMed
高影响因子
WATER ENVIRONMENT RESEARCH
·
2020
·Vol. 93
·期 3
·455-463
·
IF 1.369
Yuanhao Li,Qiufeng Lin,Cong Li,Zijian Weiguo,Luo Xu,Kejia Zhang
Perfluorooctanoic acid (PFOA) is one kind of persistent organic pollutants that is often detected in water. In recent years, the effective degradation technologies of PFOA have attracted widespread attentions. Thus, in this study, the defluorination efficiency of PFOA in different systems (i.e., ultraviolet (UV), vacuum ultraviolet (VUV), vacuum ultraviolet/persulfate (VUV/PS) and vacuum ultraviolet/residual chlorine (VUV/RC)) was evaluated. Moreover, the different impact factors (i.e., the initial concentrations of persulfate and PFOA, temperature, anions, and initial pH values) on PFOA degradation by VUV/PS system were investigated. The results showed that VUV system was more effective than UV system for PFOA defluorination. VUV system combined with persulfate would further enhance the defluorination efficiency while residual chlorine would decrease it. In VUV/PS system, the defluorination efficiency of PFOA was the best as the molar ratio of PFOA and persulfate at 1:60. Moreover, higher temperature, lower initial PFOA concentration, and acid condition were favorable for the defluorination of PFOA. Under the different influence factors, the defluorination efficiency of PFOA fitted well to the first-order reaction kinetic model. When the temperature was range from 20°C to 40°C, the value of activation energy was 8.73 kJ/mol. Besides, the inhibition effect of three kinds of anions on PFOA defluorination followed the order: > Cl − > . Practitioner points The defluorination efficiency of perfluorooctanoic acid (PFOA) in water by different VUV systems was compared. VUV system is more effective than UV system for PFOA defluorination. Persulfate will enhance the defluorination efficiency by VUV system. Hypochlorite will decrease the defluorination efficiency by VUV system.
研究领域:
环境科学
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水处理
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污染物降解
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产品关联
DOI
PubMed
高影响因子
Water
·
2024
·Vol. 16
·期 19
·2752
·
IF 3
Weibin Cai,Yuzhe Wang,Yuannan Li,Hong Ye,Fuyuan Xiao,Lei Wang,Hengjun Gai
Nanofiltration (NF) has become a widely used technology in water treatment due to its environmental friendliness, energy efficiency, cost-effectiveness, and operational simplicity. However, polyamide (PA) NF membranes still face challenges, including low permeate flux, limited resistance to organic pollutants, and inadequate resilience to residual chlorine. To address these issues, this study developed a thin-film composite (TFC) NF membrane featuring a separation layer of sandwich structure. Initially, a single separation layer of polyvinyl alcohol (PVA) NF membrane was prepared, followed by the fabrication of a PA layer on its surface, and ultimately, a second PVA layer was constructed on the PA layer. The experimental results show that the PVA/PA/PVA sandwich structure TFC exhibits high permeability to pure water and robust resistance to both pollution and residual chlorine. The PVA-0.20/PA/PVA-0.20 TFC, prepared with a 0.20%w/vPVA solution, achieved a pure water flux of up to 22.05 L m−2h−1bar−1(LMH/bar), which was 2.92 times higher than that of the control TFC membrane. Additionally, it demonstrated a salt rejection rate exceeding 96% for Na2SO4and over 99% for Congo Red (CR) and Victoria Blue B (VB). In comparison with the control TFC membrane, the PVA-0.20/PA/PVA-0.20 membrane exhibited significantly enhanced resistance to pollution. Following immersion in a 1000 ppm NaClO solution for 4 h, the rejection rate of the control TFC membrane decreased markedly and that of the PVA-0.20/PA/PVA-0.20 membrane decreased marginally, indicating excellent resistance to residual chlorine. Due to the robust overall performance of the PVA/PA/PVA membrane, it holds potential advantages for application in treating reclaimed water or slightly polluted water.
研究领域:
水处理
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膜技术
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环境工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL MONITORING AND ASSESSMENT
·
2023
·Vol. 195
·期 6
·1-15
·
IF 3
Wang Yan,Han Xue,Zhang Jie,Zhou Meng-Xuan,Liu Ai-Lin
Biological effect-based monitoring is essential for predicting or alerting to a possible deterioration in drinking water quality. In the present study, a reporter gene assay based on oxidative stress–mediated Pgst-4::GFP induction in the Caenorhabditis elegans strain VP596 (VP596 assay) was assessed for its applicability in evaluating drinking water safety and quality. This assay was used to measure the oxidative stress response in VP596 worms exposed to six ubiquitous components (As 3+ , Al 3+ , F − , NO 3 − -N, CHCl 3 , and residual chlorine) in drinking water, eight mixtures of these six components designed through orthogonal design, ninety-six unconcentrated water samples from source to tap water in two supply systems, and organic extracts (OEs) of twenty-five selected water samples. Pgst-4::GFP fluorescence was not induced by Al 3+ , F − , NO 3 − -N, and CHCl 3 , and was significantly enhanced by As 3+ and residual chlorine only at concentrations higher than their respective drinking water guideline levels. Pgst-4::GFP induction was not detected in any of the six-component mixtures. Induction of Pgst-4::GFP was observed in 9.4% (3/32) of the source water samples but not in the drinking water samples. However, a notable induction effect was revealed in the three OEs of drinking water, with a relative enrichment factor of 200. These results suggest that the VP596 assay has limited utility for screening drinking water safety by testing unconcentrated water samples; however, it offers a supplemental in vivo tool for prioritizing water samples for an enhanced quality assessment, monitoring pollutant removal performance by drinking water treatment plants, and evaluating water quality in water supplies.
研究领域:
环境科学
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毒理学
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水质评估
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Dong Hu,Wenfang Lin,Jie Zeng,Heng Zhang,Yating Wei,Xin Yu
Secondary water supply systems (SWSSs) are widely used to supply water to high-rise households in urban residential buildings. A special mode of double tanks with one used while another was spared was noted in SWSSs, which would facilitate microbial growth due to longer water stagnation in the spare tank. There are limited studies on the microbial risk of water samples in such SWSSs. In this study, the input water valves of the operational SWSSs consisting of double tanks were artificially closed and opened on time. Propidium monoazide-qPCR and high-throughput sequencing were performed to systematically investigate the microbial risks in water samples. After closing the tank input water valve, it may take several weeks to replace the bulk water in the spare tank. The residual chlorine concentration in the spare tank decreased by up to 85 % within 2–3 days compared with that in the input water. The microbial communities in the spare and used tank water samples clustered separately. High bacterial 16S rRNA gene abundance and pathogens-like sequences were detected in the spare tanks. Most antibiotic-resistant genes (11/15) in the spare tanks showed an increase in their relative abundance. Moreover, when both tanks within one SWSS were in use, the water quality of the used tank water samples deteriorated to varying degrees. Overall, running SWSSs with double tanks will reduce the replacement rate of water in one storage tank, and consumers who use taps served by the presented SWSSs may have a higher microbial risk.
研究领域:
环境科学
·
微生物学
·
水质管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Jingyi Zhang,Zuxin Xu,Wenhai Chu,Feng Ju,Wei Jin,Peng Li,Rong Xiao
During the COVID-19 pandemic, excessive amounts of disinfectants and their transformation products entered sewer systems worldwide, which was an extremely rare occurrence before. The stress of residual chlorine and disinfection by-products is not only likely to promote the spread of antibiotic resistance genes (ARGs), but also leads to the enrichment of chlorine-resistant bacteria that may also be resistant to antibiotics. Therefore, the potential impact of such discharge on ARG composition should be studied and the health risks should be assessed. Thus, this study combined high-throughput 16S rRNA gene amplicon sequencing and metagenomic analysis with long-term batch tests that involved two stages of stress and recovery to comprehensively evaluate the impact of residual chlorine on the microbial community and ARG compositions in sewer systems. The tests demonstrated that the disturbance of the microbial community structure by residual chlorine was reversible, but the change in ARG composition was persistent. This study found that vertical propagation and horizontal gene transfer jointly drove ARG composition succession in the biofilm, while the driving force was mainly horizontal gene transfer in the sediment. In this process, the biocide resistance gene (BRG) subtype chtR played an important role in promoting co-selection with ARGs through plasmids and integrative and conjugative elements. Moreover, it was further shown that the addition of sodium hypochlorite increased the risk of ARGs to human health, even after discontinuation of dosing, signifying that the impact was persistent. In general, this study strengthens the co-selection theory of ARGs and BRGs, and calls for improved disinfection strategies and more environmentally friendly disinfectants.
研究领域:
环境微生物学
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公共卫生
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分子生态学
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水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）