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Effectiveness of emergency water treatment practices in refugee camps in South Sudan.

Ali SI, Ali SS, Fesselet JF - Bull. World Health Organ. (2015)

Bottom Line: Covering water storage containers, but not other water handling practices, improved the residual chlorine levels.Abstract available from the publisher.

View Article: PubMed Central - PubMed

Affiliation: University of California-Berkeley, 100 Blum Hall, MC 5570, Berkeley, CA 64720, United States of America (USA).

ABSTRACT

Objective: To investigate the concentration of residual chlorine in drinking water supplies in refugee camps, South Sudan, March-April 2013.

Methods: For each of three refugee camps, we measured physical and chemical characteristics of water supplies at four points after distribution: (i) directly from tapstands; (ii) after collection; (iii) after transport to households; and (iv) after several hours of household storage. The following parameters were measured: free and total residual chlorine, temperature, turbidity, pH, electrical conductivity and oxidation reduction potential. We documented water handling practices with spot checks and respondent self-reports. We analysed factors affecting residual chlorine concentrations using mathematical and linear regression models.

Findings: For initial free residual chlorine concentrations in the 0.5-1.5 mg/L range, a decay rate of ~5x10(-3) L/mg/min was found across all camps. Regression models showed that the decay of residual chlorine was related to initial chlorine levels, electrical conductivity and air temperature. Covering water storage containers, but not other water handling practices, improved the residual chlorine levels.

Conclusion: The concentrations of residual chlorine that we measured in water supplies in refugee camps in South Sudan were too low. We tentatively recommend that the free residual chlorine guideline be increased to 1.0 mg/L in all situations, irrespective of diarrhoeal disease outbreaks and the pH or turbidity of water supplies. According to our findings, this would ensure a free residual chlorine level of 0.2 mg/L for at least 10 hours after distribution. However, it is unknown whether our findings are generalizable to other camps and further studies are therefore required.

No MeSH data available.


Related in: MedlinePlus

Histogram of free residual chlorine concentrations at the tapstand in refugee camps, South Sudan, March–April 2013
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Figure 1: Histogram of free residual chlorine concentrations at the tapstand in refugee camps, South Sudan, March–April 2013

Mentions: Summary statistics on water quality at the tapstands, in each of the three camps, are given in Table 3. Residual chlorine levels were similar in all camps. The turbidity was below the upper limit for effective chlorination at all sites (5 nephelometric turbidity units, NTU). Water temperatures averaged greater than 30 °C at tapstands in the morning – an indication of how hot March and April are in this setting. The pH of the water at all camps was below 8.0, the upper limit for effective chlorination. Oxidation reduction potential varied widely between camps, partially reflecting residual chlorine levels but also potentially undocumented factors. Electrical conductivity, a proxy for chemical quality, was statistically different across camps (P < 0.0001) suggesting that each camp’s source was unique. As discussed earlier, chlorination performance at each site was less than ideal. A histogram of free residual chlorine concentrations encountered at tapstands is presented in Fig. 1.


Effectiveness of emergency water treatment practices in refugee camps in South Sudan.

Ali SI, Ali SS, Fesselet JF - Bull. World Health Organ. (2015)

Histogram of free residual chlorine concentrations at the tapstand in refugee camps, South Sudan, March–April 2013
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581656&req=5

Figure 1: Histogram of free residual chlorine concentrations at the tapstand in refugee camps, South Sudan, March–April 2013
Mentions: Summary statistics on water quality at the tapstands, in each of the three camps, are given in Table 3. Residual chlorine levels were similar in all camps. The turbidity was below the upper limit for effective chlorination at all sites (5 nephelometric turbidity units, NTU). Water temperatures averaged greater than 30 °C at tapstands in the morning – an indication of how hot March and April are in this setting. The pH of the water at all camps was below 8.0, the upper limit for effective chlorination. Oxidation reduction potential varied widely between camps, partially reflecting residual chlorine levels but also potentially undocumented factors. Electrical conductivity, a proxy for chemical quality, was statistically different across camps (P < 0.0001) suggesting that each camp’s source was unique. As discussed earlier, chlorination performance at each site was less than ideal. A histogram of free residual chlorine concentrations encountered at tapstands is presented in Fig. 1.

Bottom Line: Covering water storage containers, but not other water handling practices, improved the residual chlorine levels.Abstract available from the publisher.

View Article: PubMed Central - PubMed

Affiliation: University of California-Berkeley, 100 Blum Hall, MC 5570, Berkeley, CA 64720, United States of America (USA).

ABSTRACT

Objective: To investigate the concentration of residual chlorine in drinking water supplies in refugee camps, South Sudan, March-April 2013.

Methods: For each of three refugee camps, we measured physical and chemical characteristics of water supplies at four points after distribution: (i) directly from tapstands; (ii) after collection; (iii) after transport to households; and (iv) after several hours of household storage. The following parameters were measured: free and total residual chlorine, temperature, turbidity, pH, electrical conductivity and oxidation reduction potential. We documented water handling practices with spot checks and respondent self-reports. We analysed factors affecting residual chlorine concentrations using mathematical and linear regression models.

Findings: For initial free residual chlorine concentrations in the 0.5-1.5 mg/L range, a decay rate of ~5x10(-3) L/mg/min was found across all camps. Regression models showed that the decay of residual chlorine was related to initial chlorine levels, electrical conductivity and air temperature. Covering water storage containers, but not other water handling practices, improved the residual chlorine levels.

Conclusion: The concentrations of residual chlorine that we measured in water supplies in refugee camps in South Sudan were too low. We tentatively recommend that the free residual chlorine guideline be increased to 1.0 mg/L in all situations, irrespective of diarrhoeal disease outbreaks and the pH or turbidity of water supplies. According to our findings, this would ensure a free residual chlorine level of 0.2 mg/L for at least 10 hours after distribution. However, it is unknown whether our findings are generalizable to other camps and further studies are therefore required.

No MeSH data available.


Related in: MedlinePlus