scholarly journals A rapid assessment of drinking water quality in informal settlements after a cholera outbreak in Nairobi, Kenya

2014 ◽  
Vol 13 (3) ◽  
pp. 714-725 ◽  
Author(s):  
Elizabeth Blanton ◽  
Natalie Wilhelm ◽  
Ciara O'Reilly ◽  
Everline Muhonja ◽  
Solomon Karoki ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Treatment ◽  
Disease Transmission ◽  
Rapid Assessment ◽  
Informal Settlements ◽  
Epidemic Disease ◽  
Household Water Treatment ◽  
E Coli ◽  
Household Water ◽  
Water And Sanitation Infrastructure

Populations living in informal settlements with inadequate water and sanitation infrastructure are at risk of epidemic disease. In 2010, we conducted 398 household surveys in two informal settlements in Nairobi, Kenya with isolated cholera cases. We tested source and household water for free chlorine residual (FCR) and Escherichia coli in approximately 200 households. International guidelines are ≥0.5 mg/L FCR at source, ≥0.2 mg/L at household, and <1 E. coli/100 mL. In these two settlements, 82% and 38% of water sources met FCR guidelines; and 7% and 8% were contaminated with E. coli, respectively. In household stored water, 82% and 35% met FCR guidelines and 11% and 32% were contaminated with E. coli, respectively. Source water FCR ≥0.5 mg/L (p = 0.003) and reported purchase of a household water treatment product (p = 0.002) were associated with increases in likelihood that household stored water had ≥0.2 mg/L FCR, which was associated with a lower likelihood of E. coli contamination (p < 0.001). These results challenge the assumption that water quality in informal settlements is universally poor and the route of disease transmission, and highlight that providing centralized water with ≥0.5 mg/L FCR or (if not feasible) household water treatment technologies reduces the risk of waterborne cholera transmission in informal settlements.

scholarly journals Sodium hypochlorite dosage for household and emergency water treatment: updated recommendations

2017 ◽  
Vol 16 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Natalie Wilhelm ◽  
Anya Kaufmann ◽  
Elizabeth Blanton ◽  
Daniele Lantagne
Keyword(s):  
Water Treatment ◽  
Sodium Hypochlorite ◽  
Diarrheal Disease ◽  
Microbiological Quality ◽  
Water Source ◽  
Field Studies ◽  
Household Water Treatment ◽  
E Coli ◽  
Log Reduction ◽  
Household Water

Abstract Household water treatment with chlorine can improve the microbiological quality of household water and reduce diarrheal disease. We conducted laboratory and field studies to inform chlorine dosage recommendations. In the laboratory, reactors of varying turbidity (10–300 NTU) and total organic carbon (0–25 mg/L addition) were created, spiked with Escherichia coli, and dosed with 3.75 mg/L sodium hypochlorite. All reactors had >4 log reduction of E. coli 24 hours after chlorine addition. In the field, we tested 158 sources in 22 countries for chlorine demand. A 1.88 mg/L dosage for water from improved sources of <5 or <10 NTU turbidity met free chlorine residual criteria (≤2.0 mg/L at 1 hour, ≥0.2 mg/L at 24 hours) 91–94% and 82–87% of the time at 8 and 24 hours, respectively. In unimproved water source samples, a 3.75 mg/L dosage met relaxed criteria (≤4.0 mg/L at 1 hour, ≥0.2 mg/L after 24 hours) 83% and 65% of the time after 8 and 24 hours, respectively. We recommend water from improved/low turbidity sources be dosed at 1.88 mg/L and used within 24 hours, and from unimproved/higher turbidity sources be dosed at 3.75 mg/L and consumed within 8 hours. Further research on field effectiveness of chlorination is recommended.

Evaluation of Field Testing Techniques Used in a Household Water Treatment Study in Posoltega, Nicaragua

2009 ◽  
Vol 44 (2) ◽  
pp. 122-131 ◽  
Author(s):  
Jason C. Vanderzwaag ◽  
Karen H. Bartlett ◽  
James W. Atwater ◽  
Derek Baker
Keyword(s):  
Water Quality ◽  
Water Treatment ◽  
Membrane Filtration ◽  
Limit Of Detection ◽  
Growth Media ◽  
Control Procedure ◽  
Local Health ◽  
Household Water Treatment ◽  
Significant Difference ◽  
Household Water

Abstract A field evaluation of biosand filters, a method of household water treatment, was conducted in Posoltega, Nicaragua. The evaluation consisted of water quality testing for Escherichia coli and total coliforms using membrane filtration (MF) with m-coliBlue24 growth media, and SolarCult dipslides. For each sample tested, the MF procedure was applied to two volumes differing by an order of magnitude to capture the expected range of microbial contamination. A follow-up laboratory quality assurance/quality control procedure was undertaken to validate the field methods. The average coefficient of variation was 51%, with no statistically significant difference between the field and laboratory data. The MF procedure used with m-coliBlue24 produced useful reproducible results for the microbial concentrations encountered in the field. Dipslide results were found to correlate poorly to the membrane filtration results from the field, and should not be used to test drinking water due to the high limit of detection. They may still be useful for preliminary testing of highly contaminated source water as part of a household water treatment project. Dipslides may also be a useful tool for local health representatives to promote safe water practices within the community since they are simple to use and provide a visual indicator of water quality.

scholarly journals Laboratory efficacy and field effectiveness of hollow fiber membrane microfilters used for household water treatment in Honduras

2017 ◽  
Vol 7 (1) ◽  
pp. 74-84 ◽  
Author(s):  
Anna L. Murray ◽  
Barbara Stewart ◽  
Catherine Hopper ◽  
Ellen Tobin ◽  
Jimmy Rivera ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Waters ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Geometric Mean ◽  
International Standards ◽  
Fiber Membrane ◽  
Household Water Treatment ◽  
E Coli ◽  
Household Water

The Sawyer PointONE™ hollow fiber membrane filter is increasingly promoted for long-term household water treatment in developing countries. Limited data demonstrate PointONE™ microbiological laboratory efficacy and short-term diarrheal disease reduction among users, but household microbiological data is lacking. To compare laboratory and household PointONE™ filter microbiological performance, we enumerated Escherichia coli (E. coli) and total coliforms in source and filtrate water from: (1) one new filter with E. coli-spiked water (107–109 CFU/100 mL) in the laboratory, (2) one new filter with natural Maine and Honduran surface waters, and (3) 50 filters used in Honduran homes for 1–3 years. In laboratory tests, all filtrate samples had <1 CFU/100 mL E. coli (>99.99999% reduction). In natural surface waters, all filtrate samples had ≤1 MPN/100 mL E. coli (≥99.5% reduction). In households, filtrate samples had geometric mean 5.1 MPN/100 mL E. coli (90% reduction), with only 30% of filtrate samples complying with international standards of undetectable E. coli. Total coliform presence in natural water filtrate varied for both new and household filters. The discrepancy between laboratory and household results and premature filter failure are not well understood. Further research is recommended to understand this performance disparity and determine filter failure mechanisms in households.

scholarly journals Evaluation of use, acceptability, and effectiveness of household water filter systems in Honduras, 2016–2017

2018 ◽  
Vol 8 (4) ◽  
pp. 809-816
Author(s):  
Kirsten Fagerli ◽  
Jacqueline Hurd ◽  
Emma Wells ◽  
Jarred McAteer ◽  
Sunkyung Kim ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Treatment ◽  
Program Implementation ◽  
Water Filter ◽  
E Coli ◽  
The Past ◽  
Quality Guidelines ◽  
Household Water ◽  
And Performance

Abstract We evaluated a household hollow fiber water filter program in 11 Honduran villages by assessing filter uptake and water quality. Filters were purchased by 90% of households; of these, 94% reported use within the past week. When comparing water treatment methods between baseline and follow-up, there were increases in the proportion of households reporting water treatment (74% vs. 93%, p < 0.001) and treatment by filtration (19% vs. 85%, p < 0.001), and decreased purchase of bottled water (44% vs 6%, p < 0.001), indicating acceptability of the water filtration systems. There was a significant decrease in the presence of Escherichia coli in water samples taken from 35 households at baseline and follow-up in water filter systems (p < 0.001). As a result, 68% of samples met WHO water quality guidelines (no detectable E. coli) 6–12 months after program implementation. Observations of filter stands revealed a 6-inch gap between the top (reservoir) bucket and bottom (filtrate recipient) bucket that could have permitted animals, insects, hands, or other objects to touch filtered water. We recommend a redesign of filter stands to eliminate the gap between buckets, and a longer-term follow-up to assess filter durability and performance.

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