Effectiveness of water chlorination programs along the emergency-transition-post-emergency continuum: Evaluations of bucket, in-line, and piped water chlorination programs in Cox’s Bazar

Sikder, Mustafa; String, Gabrielle; Kamal, Yarmina; Farrington, Michelle; Rahman, Abm Sadiqur; Lantagne, Daniele

doi:10.1016/j.watres.2020.115854

Cited by 12 publications

(17 citation statements)

References 21 publications

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“…Studies assessed the technical efficacy of passive chlorinators directly (by measuring FCR at multiple time points) and/or indirectly (by using E. coli measurements as an indicator for disinfection). Although WHO guidelines for residual in piped water systems recommend 0.2–0.5 mg/L FCR as adequate for disinfection, 49 some studies defined adequate chlorine delivery as any amount of measurable free chlorine above the limit of detection 17 , 32 , 38 , 40 , 44 , 45 or used their own range of desired doses on the basis of other standards. 21 , 33 , 34 , 42 , 46 , 48 Dosing consistency was reported as the percentage of samples with chlorine concentrations within the study’s indicated range ( Table 2 ).…”

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

“…Another study by Sikder et al 45 compared a handpump passive chlorinator (PurAll 50H) to centralized piped water chlorination and batch-level bucket chlorination. All households (100%, n = 159) with water treated by large-scale piped water chlorination had “low risk” 49 water (<10 E. coli CFU/100 mL), followed by passive chlorination (89%, n = 180 households) and batch-level bucket chlorination (71%, n = 148 households).…”

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

“…This variability in reporting metrics for bacterial contamination reduction makes it difficult to compare these chlorinators’ effectiveness and performance. 26 , 32 , 44 , 45 …”

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

“…Another study by Sikder et al compared a handpump passive chlorinator (PurAll 50H) to centralized piped water chlorination and batch-level bucket chlorination. All households (100%, n = 159) with water treated by large-scale piped water chlorination had “low risk” water (<10E.…”

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

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Passive In-Line Chlorination for Drinking Water Disinfection: A Critical Review

Lindmark

Cherukumilli

Crider

et al. 2022

Environ. Sci. Technol.

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The world is not on track to meet Sustainable Development Goal 6.1 to provide universal access to safely managed drinking water by 2030. Removal of priority microbial contaminants by disinfection is one aspect of ensuring water is safely managed. Passive chlorination (also called in-line chlorination) represents one approach to disinfecting drinking water before or at the point of collection (POC), without requiring daily user input or electricity. In contrast to manual household chlorination methods typically implemented at the point of use (POU), passive chlorinators can reduce the user burden for chlorine dosing and enable treatment at scales ranging from communities to small municipalities. In this review, we synthesized evidence from 27 evaluations of passive chlorinators (in 19 articles, 3 NGO reports, and 5 theses) conducted across 16 countries in communities, schools, health care facilities, and refugee camps. Of the 27 passive chlorinators we identified, the majority (22/27) were solid tablet or granular chlorine dosers, and the remaining devices were liquid chlorine dosers. We identified the following research priorities to address existing barriers to scaled deployment of passive chlorinators: (i) strengthening local chlorine supply chains through decentralized liquid chlorine production, (ii) validating context-specific business models and financial sustainability, (iii) leveraging remote monitoring and sensing tools to monitor real-time chlorine levels and potential system failures, and (iv) designing handpump-compatible passive chlorinators to serve the many communities reliant on handpumps as a primary drinking water source. We also propose a set of reporting indicators for future studies to facilitate standardized evaluations of the technical performance and financial sustainability of passive chlorinators. In addition, we discuss the limitations of chlorine-based disinfection and recognize the importance of addressing chemical contamination in drinking water supplies. Passive chlorinators deployed and managed at-scale have the potential to elevate the quality of existing accessible and available water services to meet “safely managed” requirements.

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Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

“…This variability in reporting metrics for bacterial contamination reduction makes it difficult to compare these chlorinators’ effectiveness and performance. 26 , 32 , 44 , 45 …”

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

Section: Implementation and Evaluation Studiesmentioning

confidence: 99%

See 2 more Smart Citations

Passive In-Line Chlorination for Drinking Water Disinfection: A Critical Review

Lindmark

Cherukumilli

Crider

et al. 2022

Environ. Sci. Technol.

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“…To prevent outbreaks in refugee and IDP settlements, drinking water needs to be protected against pathogenic recontamination until the end of the household storage period when the final cup is consumed. Global drinking water quality guidelines recommend providing at least 0.2 mg/L of free residual chlorine (FRC) throughout the post-distribution period to prevent recontamination, and past research has identified that this is sufficient to prevent recontamination by priority pathogens in humanitarian settings such as cholera and hepatitis E [10][11][12][13][14][15]. Thus, water system operators must determine how much FRC is needed at the point-of-distribution to ensure that there is still at least 0.2 mg/L of FRC at the point-of-consumption.…”

Section: Introductionmentioning

confidence: 99%

Modelling point-of-consumption residual chlorine in humanitarian response: Can cost-sensitive learning improve probabilistic forecasts?

et al. 2022

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Ensuring sufficient free residual chlorine (FRC) up to the time and place water is consumed in refugee settlements is essential for preventing the spread of waterborne illnesses. Water system operators need accurate forecasts of FRC during the household storage period. However, factors that drive FRC decay after water leaves the piped distribution system vary substantially, introducing significant uncertainty when modelling point-of-consumption FRC. Artificial neural network (ANN) ensemble forecasting systems (EFS) can account for this uncertainty by generating probabilistic forecasts of point-of-consumption FRC. ANNs are typically trained using symmetrical error metrics like mean squared error (MSE), but this leads to forecast underdispersion forecasts (the spread of the forecast is smaller than the spread of the observations). This study proposes to solve forecast underdispersion by training an ANN-EFS using cost functions that combine alternative metrics (Nash-Sutcliffe efficiency, Kling Gupta Efficiency, Index of Agreement) with cost-sensitive learning (inverse FRC weighting, class-based FRC weighting, inverse frequency weighting). The ANN-EFS trained with each cost function was evaluated using water quality data from refugee settlements in Bangladesh and Tanzania by comparing the percent capture, confidence interval reliability diagrams, rank histograms, and the continuous ranked probability. Training the ANN-EFS using the cost functions developed in this study produced up to a 70% improvement in forecast reliability and dispersion compared to the baseline cost function (MSE), with the best performance typically obtained by training the model using Kling-Gupta Efficiency and inverse frequency weighting. Our findings demonstrate that training the ANN-EFS using alternative metrics and cost-sensitive learning can improve the quality of forecasts of point-of-consumption FRC and better account for uncertainty in post-distribution chlorine decay. These techniques can enable humanitarian responders to ensure sufficient FRC more reliably at the point-of-consumption, thereby preventing the spread of waterborne illnesses.

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