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Zhang C, Sienkiewicz N, Struewing I, Mistry JH, Buse H, Hu Z, Lu J. Reconsider the burn: The transient effect of a chlorine burn on controlling opportunistic pathogens in a full-scale chloraminated engineered water system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 933:172690. [PMID: 38670361 DOI: 10.1016/j.scitotenv.2024.172690] [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: 12/19/2023] [Revised: 04/20/2024] [Accepted: 04/20/2024] [Indexed: 04/28/2024]
Abstract
Nitrification is a serious water-quality issue in chloraminated engineered water systems (EWSs). Nitrification is often remediated by a chlorine burn (i.e., a free‑chlorine conversion), a short-term switch from chloramination to chlorination in EWSs. Opportunistic pathogens (OPs) are the dominant infectious agents in EWSs. However, the responses of OPs to a chlorine burn are unknown. This study for the first time assessed how a chlorine burn affected OPs in a full-scale EWS. We determined the impact of a 1.5-month chlorine burn on four dominant OPs (Legionella, Mycobacterium, Pseudomonas, and Vermamoeba vermiformis) in a representative full-scale chloraminated EWS in the United States. Legionella and Mycobacterium were the most abundant OPs. In the water main, the summed concentration of the four OPs during the chlorine burn [3.27 ± 1.58 log10(GCN·L-1); GCN: genome or gene copy number] was lower (p ≤ 0.001) than before the burn [4.83 ± 0.50 log10(GCN·L-1)]. After the burn, the summed concentration increased to 4.27 ± 0.68 log10(GCN·L-1), comparable to before the burn (p > 0.05), indicating a transient effect of the chlorine burn in the water main. At the residential sites, the summed concentrations of the four OPs were comparable (p > 0.05) at 5.50 ± 0.84, 5.27 ± 1.44, and 5.08 ± 0.71 log10(GCN·L-1) before, during, and after the chlorine burn, respectively. Therefore, the chlorine burn was less effective in suppressing OP (re)growth in the premise plumbing. The low effectiveness might be due to more significant water stagnation and disinfectant residual decay in the premise plumbing. Indeed, for the entire sampling period, the total chlorine residual concentration in the premise plumbing (1.8 mg Cl2·L-1) was lower than in the water main (2.4 mg Cl2·L-1). Consequently, for the entire sampling period, the summed concentration of the four OPs in the premise plumbing [5.26 ± 1.08 log10(GCN·L-1)] was significantly higher (p < 0.001) than in the water main [4.04 ± 1.25 log10(GCN·L-1)]. In addition, the chlorine burn substantially increased the levels of disinfection by-products (DBPs) in the water main. Altogether, a chlorine burn is transient or even ineffective in suppressing OP (re)growth but raises DBP concentrations in chloraminated EWSs. Therefore, the practice of chlorine burns to control nitrification should be optimized, reconsidered, or even replaced.
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Affiliation(s)
- Chiqian Zhang
- Civil Engineering Program, College of Engineering & Computer Science, Arkansas State University, AR 72467, United States
| | - Nathan Sienkiewicz
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Jatin H Mistry
- United States Environmental Protection Agency, Region 6, Dallas, TX 75270, United States
| | - Helen Buse
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Zhiqiang Hu
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, MO 65211, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States.
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Mikhail IE, Murray E, Bluett S, Astrakhantseva S, Paull B. Simultaneous separation and detection of monochloramine, nitrite, and nitrate by step-gradient mixed-mode ion chromatography: Translation from benchtop to portable ion chromatograph. Anal Chim Acta 2024; 1304:342557. [PMID: 38637041 DOI: 10.1016/j.aca.2024.342557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/20/2024]
Abstract
BACKGROUND Nitrite (NO2-) and nitrate (NO3-) can be produced in the distribution systems of chloraminated drinking water due to the nitrification of ammonia. The most applied inorganic chloramine for this purpose, namely monochloramine (NH2Cl), is also released into aquatic environments from water treatment plants' effluent and within industrial waste streams. Within the treatment process, the continuous monitoring of disinfectant levels is necessary to limit the harmful disinfectant by-product (DBP) formation. Currently, NH2Cl can interfere with nutrient analysis in water samples, and there are no analytical techniques available for the simultaneous analysis of NH2Cl, NO2-, and NO3-. RESULTS A green analytical method based on mixed-mode ion chromatography, specifically ion exchange and ion exclusion modes, was developed for the simultaneous separation and detection of NH2Cl, NO2-, and NO3-. The separation was achieved using a Dionex IonPac AG15 column guard column and a step gradient elution involving deionized water and 120.0 mM NaCl. The method was developed using a benchtop HPLC with a custom-made multi-wavelength UV absorbance detector with a 50-mm flow cell to enable the sensitive detection of NH2Cl, NO2-, and NO3- at 240 nm, 220 nm, and 215 nm, respectively. The developed method was then transferred to a portable ion chromatography (IC) system, the Aquamonitrix analyser. The total run time was less than 10 min for both systems. The benchtop HPLC method had a limit of detection (LOD) of 0.07 μg mL-1 as Cl2 for NH2Cl, 0.01 μg mL-1 for NO2-, and 0.03 μg mL-1 for NO3-. The LODs obtained using the portable Aquamonitrix analyser were found to be 0.36 μg mL-1 as Cl2, 0.02 μg mL-1, and 0.11 μg mL-1 for NH2Cl, NO2-, and NO3-, respectively. Excellent linearity (r ≥ 0.9999) was achieved using the portable analyser over the studied concentration ranges. The developed system was applied to the analysis of spiked municipal drinking water samples and showed excellent repeatability for the three analytes at three different concentration levels (RSD of triplicate recovery experiments ≤ 1.9 %). Moreover, the variation in retention time was negligible for the three target analytes with RSD ≤ 0.8 % over 12 runs. SIGNIFICANCE We are reporting the first ion chromatographic method for the simultaneous separation and detection of NH2Cl, NO2-, and NO3- in water samples. The monitoring of NH2Cl, NO2-, and NO3- is critical for the determination of disinfectant dosing, water quality, and nitrification status. The developed method can be applied using a benchtop HPLC or via the portable automated IC system to monitor for the three target compounds analysis in water treatment plants.
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Affiliation(s)
- Ibraam E Mikhail
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences (Chemistry), University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Eoin Murray
- Research & Development, Aquamonitrix Ltd., Tullow, Carlow, Ireland; Research & Development, T.E. Laboratories Ltd. (TelLab), Tullow, Carlow, Ireland
| | - Simon Bluett
- Research & Development, Aquamonitrix Ltd., Tullow, Carlow, Ireland
| | - Snezhana Astrakhantseva
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences (Chemistry), University of Tasmania, Hobart, Tasmania, 7001, Australia
| | - Brett Paull
- Australian Centre for Research on Separation Science (ACROSS), School of Natural Sciences (Chemistry), University of Tasmania, Hobart, Tasmania, 7001, Australia.
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Chu CH, Lin YX, Liu CK, Lai MC. Development of Innovative Online Modularized Device for Turbidity Monitoring. SENSORS (BASEL, SWITZERLAND) 2023; 23:3073. [PMID: 36991784 PMCID: PMC10051103 DOI: 10.3390/s23063073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
Given progress in water-quality analytical technology and the emergence of the Internet of Things (IoT) in recent years, compact and durable automated water-quality monitoring devices have substantial market potential. Due to susceptibility to the influence of interfering substances, which lowers measurement accuracy, existing automated online monitoring devices for turbidity, a key indicator of a natural water body, feature a single light source and are thus insufficient for more complicated water-quality measurement. The newly developed modularized water-quality monitoring device boasts dual light sources (VIS/NIR), capable of measuring the intensity of scattering, transmission, and reference light at the same time. Coupled with a water-quality prediction model, it can attain a good estimate for continuing monitoring of tap water (<2 NTU, error < 0.16 NTU, relative error < 19.6%) and environmental water samples (<400 NTU, error < 3.86 NTU, relative error < 2.3%). This indicates the optical module can both monitor water quality in low turbidity and provide water-treatment information alerts in high turbidity, thereby materializing automated water-quality monitoring.
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Affiliation(s)
- Chen-Hua Chu
- Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 310, Taiwan
| | - Yu-Xuan Lin
- Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 310, Taiwan
| | - Chun-Kuo Liu
- Center for Measurement Standards, Industrial Technology Research Institute, Hsinchu 310, Taiwan
| | - Mei-Chun Lai
- Green Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 310, Taiwan
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Shi Z, Chow CWK, Fabris R, Liu J, Jin B. Applications of Online UV-Vis Spectrophotometer for Drinking Water Quality Monitoring and Process Control: A Review. SENSORS 2022; 22:s22082987. [PMID: 35458971 PMCID: PMC9024714 DOI: 10.3390/s22082987] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 03/22/2022] [Accepted: 04/07/2022] [Indexed: 01/27/2023]
Abstract
Water quality monitoring is an essential component of water quality management for water utilities for managing the drinking water supply. Online UV-Vis spectrophotometers are becoming popular choices for online water quality monitoring and process control, as they are reagent free, do not require sample pre-treatments and can provide continuous measurements. The advantages of the online UV-Vis sensors are that they can capture events and allow quicker responses to water quality changes compared to conventional water quality monitoring. This review summarizes the applications of online UV-Vis spectrophotometers for drinking water quality management in the last two decades. Water quality measurements can be performed directly using the built-in generic algorithms of the online UV-Vis instruments, including absorbance at 254 nm (UV254), colour, dissolved organic carbon (DOC), total organic carbon (TOC), turbidity and nitrate. To enhance the usability of this technique by providing a higher level of operations intelligence, the UV-Vis spectra combined with chemometrics approach offers simplicity, flexibility and applicability. The use of anomaly detection and an early warning was also discussed for drinking water quality monitoring at the source or in the distribution system. As most of the online UV-Vis instruments studies in the drinking water field were conducted at the laboratory- and pilot-scale, future work is needed for industrial-scale evaluation with ab appropriate validation methodology. Issues and potential solutions associated with online instruments for water quality monitoring have been provided. Current technique development outcomes indicate that future research and development work is needed for the integration of early warnings and real-time water treatment process control systems using the online UV-Vis spectrophotometers as part of the water quality management system.
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Affiliation(s)
- Zhining Shi
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia; (Z.S.); (B.J.)
| | - Christopher W. K. Chow
- Sustainable Infrastructure and Resource Management, UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
- Correspondence:
| | - Rolando Fabris
- South Australia Water Corporation, Adelaide, SA 5000, Australia;
| | - Jixue Liu
- UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia;
| | - Bo Jin
- School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA 5005, Australia; (Z.S.); (B.J.)
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Hossain S, Chow CWK, Cook D, Sawade E, Hewa GA. Review of Nitrification Monitoring and Control Strategies in Drinking Water System. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19074003. [PMID: 35409686 PMCID: PMC8997939 DOI: 10.3390/ijerph19074003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 03/17/2022] [Accepted: 03/23/2022] [Indexed: 12/29/2022]
Abstract
Nitrification is a major challenge in chloraminated drinking water systems, resulting in undesirable loss of disinfectant residual. Consequently, heterotrophic bacteria growth is increased, which adversely affects the water quality, causing taste, odour, and health issues. Regular monitoring of various water quality parameters at susceptible areas of the water distribution system (WDS) helps to detect nitrification at an earlier stage and allows sufficient time to take corrective actions to control it. Strategies to monitor nitrification in a WDS require conducting various microbiological tests or assessing surrogate parameters that are affected by microbiological activities. Additionally, microbial decay factor (Fm) is used by water utilities to monitor the status of nitrification. In contrast, approaches to manage nitrification in a WDS include controlling various factors that affect monochloramine decay rate and ammonium substrate availability, and that can inhibit nitrification. However, some of these control strategies may increase the regulated disinfection-by-products level, which may be a potential health concern. In this paper, various strategies to monitor and control nitrification in a WDS are critically examined. The key findings are: (i) the applicability of some methods require further validation using real WDS, as the original studies were conducted on laboratory or pilot systems; (ii) there is no linkage/formula found to relate the surrogate parameters to the concentration of nitrifying bacteria, which possibly improve nitrification monitoring performance; (iii) improved methods/monitoring tools are required to detect nitrification at an earlier stage; (iv) further studies are required to understand the effect of soluble microbial products on the change of surrogate parameters. Based on the current review, we recommend that the successful outcome using many of these methods is often site-specific, hence, water utilities should decide based on their regular experiences when considering economic and sustainability aspects.
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Affiliation(s)
- Sharif Hossain
- Scarce Resources and Circular Economy (ScaRCE), UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia; (C.W.K.C.); (G.A.H.)
- Correspondence:
| | - Christopher W. K. Chow
- Scarce Resources and Circular Economy (ScaRCE), UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia; (C.W.K.C.); (G.A.H.)
- Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - David Cook
- South Australian Water Corporation, Adelaide, SA 5000, Australia; (D.C.); (E.S.)
| | - Emma Sawade
- South Australian Water Corporation, Adelaide, SA 5000, Australia; (D.C.); (E.S.)
| | - Guna A. Hewa
- Scarce Resources and Circular Economy (ScaRCE), UniSA STEM, University of South Australia, Mawson Lakes, SA 5095, Australia; (C.W.K.C.); (G.A.H.)
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