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Safe Drinking Water
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Abstracts: PUR Purifier
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COMBINING DRINKING WATER TREATMENT AND HAND WASHING FOR DIARRHEA PREVENTION, A CLUSTER RANDOMISED CONTROLLED TRIAL
Stephen P. Luby1, Mubina Agboatwalla2, John Painter1, Arshad Altaf3, Ward Billhimer4, Bruce Keswick4 and Robert M. Hoekstra1
1 Division of Bacterial and Mycotic Diseases, National Centers for Infectious Diseases, Centers for Disease Control & Prevention, Atlanta, Georgia, USA
2 Health Oriented Preventive Education, Karachi, Pakistan
3 Community Health Sciences, Aga Khan University, Karachi, Pakistan
4 The Procter and Gamble Company, Cincinnati, Ohio, USA
Corresponding Author Dr Steve Luby, Programme Infectious Diseases and Vaccine Sciences, ICDDRB: Centre for Health and Population Research, GPO Box 128, Mohakhali, Dhaka 1212 Bangladesh. E-mail: sluby@icddrb.org
Objectives
To evaluate the effectiveness of point of use water treatment with flocculent-disinfectant on reducing diarrhea and the additional benefit of promoting hand washing with soap.
Methods
The study was conducted in squatter settlements of Karachi, Pakistan, where diarrhea is a leading cause of childhood death. Interventions were randomly assigned to 47 neighbourhoods. Households in 10 neighbourhoods received diluted bleach and a water vessel; nine neighbourhoods received soap and were encouraged to wash hands; nine neighbourhoods received flocculent-disinfectant water treatment and a water vessel; 10 neighbourhoods received disinfectant-disinfectant water treatment and soap and were encouraged to wash hands; and nine neighbourhoods were followed as controls. Field workers visited households at least once a week from April to December 2003 to promote use of the interventions and to collect data on diarrhea.
Results
Study participants in control neighbourhoods had diarrhea on 5.2% of days. Compared to controls, participants living in intervention neighbourhoods had a lower prevalence of diarrhea: 55% (95% CI 17%, 80%) lower in bleach and water vessel neighbourhoods, 51% (95% CI 12%, 76%) lower in hand washing promotion with soap neighbourhoods, 64% lower (95% CI 29%, 90%) in disinfectant-disinfectant neighbourhoods, and 55% (95% CI 18%, 80%) lower in disinfectant-disinfectant plus hand washing with soap neighbourhoods.
Conclusions
With an intense community-based intervention and supplies provided free of cost, each of the home-based interventions significantly reduced diarrhea. There was no benefit by combining hand washing promotion with water treatment. (link to study)
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POINT-OF-USE WATER TREATMENT AND DIARRHEA REDUCTION IN THE EMERGENCY CONTEXT: AN EFFECTIVENESS TRIAL IN LIBERIA
Shannon Doocy and Gilbert Burnham
Johns Hopkins University Center for Refugee and Disaster Response, Baltimore, MD, USA
Corresponding Author Shannon Doocy, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Suite E8132, 615 N, Wolfe Street, Baltimore, MD 21205, USA. Tel.: 410-502-2628; Fax: 410-614-1419; E-mail: sdoocy@jhsph.edu
Summary
Communicable diseases are of particular concern in conflict and disaster-affected populations that reside in camp settings. In the acute emergency phase, diarrheal diseases have accounted for more than 40% of deaths among camp residents. Clear limitations exist in current water treatment technologies, and few products are capable of treating turbid water. We describe the findings of a 12-week effectiveness study of point-of-use water treatment with a flocculant–disinfectant among 400 households in camps for displaced populations in Monrovia, Liberia. In intervention households, point-of-use water treatment with the flocculant–disinfectant plus improved storage reduced diarrhea incidence by 90% and prevalence by 83%, when compared with control households with improved water storage alone. Among the intervention group, residual chlorine levels met or exceeded Sphere standards in 85% (95% CI: 83.1–86.8) of observations with a 95% compliance rate. (link to study)
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FLOCCULENT-DISINFECTANT POINT-OF-USE WATER TREATMENT FOR REDUCING ARSENIC EXPOSURE IN BANGLADESH
D.M. Norton1, M. Rahman2, A.L. Shane1, Z. Hossain2, R.M. Kulick3, M. Bhuiyan2, M.A. Wahed2, M. Yunus2, R. Breiman2, A. Henderson1, B.H. Keswick3, S. Luby1
1Centers for Disease Control and Prevention, Atlanta, GA, USA
2ICDDR, B: Centre for Health and Population Research, Dhaka-1000, Bangladesh
3Procter & Gamble Health Sciences Institute, Mason, OH, USA
Background
An estimated two-thirds of all tubewells placed in Bangladesh to provide safer sources of drinking water may be contaminated with harmful levels of arsenic.
Objective
To evaluate the effectiveness of treating arsenic contaminated tubewell water with a point-of-use flocculent-disinfectant for reducing exposure to arsenic.
Methodology
The study was conducted in Matlab, Bangladesh. We provided the flocculent-disinfectant to 105 households drawing their drinking water from tubewells contaminated with >50 ppb arsenic (determined by a rapid field test) for 12 weeks. One woman in each household was taught how to treat tubewell water and was instructed to drink treated water only. Drinking water and spot urine samples were collected at baseline and 2, 5, 9 and 12 weeks after intervention. Drinking water was analysed for total arsenic, and spot urines for the sum of arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid (total urinary arsenic) by atomic absorption spectrophotometry.
Results
The mean baseline arsenic concentration in tubewell water was 162 ppb. The mean total urinary arsenic concentration at baseline was 439 ug/g creatinine. Following initiation of the intervention, arsenic concentrations in drinking water decreased by a mean of 138 ppb (85%); 88% met the Bangladesh standard of <50 ppb. Urinary arsenic concentrations decreased by a mean of 163 ug/g creatinine (37%).
Conclusions
The flocculent-disinfectant markedly reduced arsenic levels in tubewell water and, to a lesser extent, urinary arsenic in women who consumed treated water. The lesser reduction in urine arsenic may be a result of continued exposure (through untreated drinking water, other dietary or environmental sources), or metabolic factors.
D.M. Norton, M. Rahman, A.L. Shane, Z. Hossain, R.M. Kulick, M. Bhuiyan, M.A. Wahed, M. Yunus, R.F. Breiman, A. Henderson, B.H. Keswick, S. Luby. 2003. A Combined Flocculent-Disinfectant Point-of-Use Water Treatment Strategy for Reducing Arsenic Exposure in Rural Bangladesh. 10th Asian Conference on Diarrhoeal Diseases and Nurtition (ASCODD), Dhaka, Bangladesh.
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FIELD TRIAL OF A FLOCCULENT-DISINFECTANT TREATMENT OF POND WATER FOR DRINKING IN BANGLADESH
D.M. Norton1, M. Rahman2, Z. Hossain2, A.L. Shane1, M.S. Islam2, R.M. Kulick3, M. Bhuiyan2, R. Breiman2, B.H. Keswick3, S. Luby1
1Centers for Disease Control and Prevention, Atlanta, GA, USA
2ICDDR, B: Centre for Health and Population Research, Dhaka-1000, Bangladesh
3Procter & Gamble Health Sciences Institute, Mason, OH, USA
Background
The continued prevalence of diarrheal disease in Bangladesh, along with arsenic contamination of tubewells, emphasizes the urgent need for innovative, practical strategies to provide safe drinking water.
Objective
To evaluate the efficacy of a combined flocculent-disinfectant point-of-use water treatment for improving the quality and microbial safety of surface pond water in rural Bangladesh.
Methodology
Water from 35 surface ponds in Matlab, Bangladesh was collected and treated with the flocculent-disinfectant three times, at one month intervals. Samples collected before and after treatment were analysed for faecal coliforms by a membrane filtration technique using filter coliform agar. Water samples were classified as potable if they met the WHO bacterial guideline of <1 CFU/100 ml faecal coliform. Free chlorine levels were measured 30 minutes after treatment. Turbidity was measured with a portable turbidity meter. Since the samples were from surface water, arsenic levels were not evaluated.
Results
Prior to treatment, all samples (n=101) were non-potable, and were contaminated with a mean of 2.9x104 CFU/100 ml faecal coliforms. Turbidity ranged from 6-92 NTU, with a mean of 32 NTU. Following treatment, 97 (96%) samples met the potability guideline. Treatment resulted in a mean 87% reduction in turbidity (mean 4 NTU) with 93% of the samples meeting the WHO turbidity guideline of <5 NTU. Free chlorine was detected in 83% of the samples.
Conclusions
Following treatment with the flocculent-disinfectant, 96% of the surface pond water samples met the WHO bacterial potability guideline. Samples showed markedly improved clarity. This strategy may be useful in programs for improving the quality and safety of drinking water.
D.M. Norton, M. Rahman, Z. Hossain, A.L. Shane, M.S. Islam, R.M. Kulick, M. Bhuiyan, R. Breiman, B.H. Keswick, S. Luby .2003. Field Trial of a Flocculent-Disinfectant Point-of-Use Water Treatment for Improving the Quality and Microbial Safety of Surface Pond Water in Bangladesh. 10th Asian Conference on Diarrhoeal Diseases and Nurtition (ASCODD), Dhaka, Bangladesh
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VIRAL INACTIVATION IN SURFACE WATER USING A METAL COAGULANT COMBINED WITH GRANULAR SLOW-RELEASE CHLORINE
B. T. Le, J. G. Jacangelo, K. J. Schwab
Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD.
In many areas of the world, drinking water sources are highly contaminated and not suitable for direct human consumption. While numerous studies have been conducted on viral removal by coagulation and viral inactivation by free chlorine applied in an aqueous form, there is little information on the use of a coagulant in combination with a slow release disinfection scheme. This study evaluated the viral inactivation/removal effectiveness of a metal coagulant combined with granular slow-release chlorine. One L samples of 1mM phosphate buffer (pH 7) or surface water were seeded with purified preparations of MS2 bacteriophage, poliovirus type 1 (PV1), and feline calicivirus (FCV). Viral stock solutions were purified by 100 kD ultrafiltration to reduce chlorine demand and viral aggregates disassociated by 0.1 micron filtration. Portions of the coagulant/chlorine product were added to virus-containing water samples and mixed constantly at 80 RPM for 5 m. Free chlorine and viral samples were collected and assayed by colorimetric titration and cell culture, respectively, at T=0, 10 seconds(s), 20 s, 30 s, 45 s, 1 m, 3 m, 5 m, 15 m, and 30 m. The correlation between free chlorine concentration, viral inactivation/removal and time was evaluated. The slow-release chlorine resulted in a free chorine concentration ranging from 0.8 mg/L after 10 to 20 s to a peak of approximately 1.2 to 2mg/L after 2 minutes. On average, 0.5-1 log of MS2 was inactivated within 10 s, 1.5-3 logs after 45 s and 4-5 logs after 5 minutes. Two to 3 logs of PV1 and FCV were inactivated after 10 s and 5 logs after 45 s. High levels of viral inactivation were observed during mixing prior to the settling of the formed floc. In summary, the utilization of slow-release chlorine resulted in high levels of free chlorine (>1 mg/L) being present in treated water for extended periods of time. Although free chlorine concentration in the water can be variable due to water quality, the levels obtained were sufficient to inactivate 5 logs of different viruses within 2 minutes. Data also showed that MS2 was more resistant to chlorine than both PV1 and FCV, and can be a conservative indicator for viral inactivation.
B. T. Le, J. G. Jacangelo, K. J. Schwab; Viral Inactivation In Surface Water Using A Metal Coagulant Combined With Granular Slow-Release Chlorine. Johns Hopkins University, Bloomberg School of Public Health, Baltimore. American Society for Microbiology Annual Meeting, May, 2003
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EVALUATION OF A FLOCCULATING AGENT (PUR) FOR REMOVAL OF CYANOBACTERIA AND CYANOTOXINS FROM POTABLE WATER SUPPLIES
Allen, E.A.D.1, Carmichael, W.W.1, Keswick, B.2
1Department of Biological Sciences, Wright State University, Dayton, OH, USA.
2The Procter and Gamble Health Sciences Institute, Mason, OH, USA
In areas of the world where surface water is used for drinking there is a need to remove suspended solids including silt and bacteria. A flocculating agent has been developed that accomplishes this and requires little equipment.
The flocculating agent (PUR)® developed by Procter and Gamble is a powder contained in a single use sachet that is added to 10 litres of raw water with agitation. After flocculation and precipitation, the water is filtered through a cloth to remove the remaining precipitate. Hypochlorite is incorporated in the flocculating agent to act as a disinfectant. We examined the ability of PUR® to remove toxin-producing cyanobacteria from water and see if the toxins were present in the cleared water. Four cyanobacteria were used: Microcystis producing microcystin, Cylindrospermopsis producing cylindrospermopsisn, Anabaena producing anatoxin and Aphanizominon producing saxitoxin. The density of the cell suspensions used corresponded to a heavy bloom. Two flocculations were required to remove all of the cells. Free chlorine concentration fell rapidly to undetectable concentration during the first flocculation and was usually less than 0.5 ppm after the second. Cyanotoxin concentrations were determined in the suspension (lysed cells plus medium), the medium only and in the treated water after the first and second flocculations. Anatoxin-a was reduced to about 60% of the levels present in the cells and medium after the second flocculation while microcystin concentrations were reduced to less than 5%. Cylindrospermopsin, which is readily released by the cells, was reduced to undetectable levels only after the second flocculation. Saxitoxin was reduced to less than 10% after the second flocculation. PUR is capable of rapidly removing cyanobacteria from water, does not cause a release of toxins from the cells during the flocculation process and does reduce the concentration of toxins both by the removal of cells and presumably by adsorption. The treated water is acceptable for drinking.
Allen, E. A., W. W. Carmichael and B. H. Keswick. 2004. The Evaluation of a Flocculating Agent (PUR) for the Removal of Cyanobacteria and their Toxins from Potable Water Supplies. Sixth International Conference on Toxic Cyanobacteria, Bergen, Norway
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