Accuracy, precision, usability, and cost of free chlorine residual testing methods

May 18, 2015 · 0 comments

Accuracy, precision, usability, and cost of free chlorine residual testing methods. Journal of Water and Health Vol 13 No 1 pp 79–90 © IWA Publishing 2015 doi:10.2166/wh.2014.195.

Authors: Anna Murray and Daniele Lantagne

Chlorine is the most widely used disinfectant worldwide, partially because residual protection is maintained after treatment. This residual is measured using colorimetric test kits varying in accuracy, precision, training required, and cost. Seven commercially available colorimeters, color wheel and test tube comparator kits, pool test kits, and test strips were evaluated for use in low-resource settings by: (1) measuring in quintuplicate 11 samples from 0.0–4.0 mg/L free chlorine residual in laboratory and natural light settings to determine accuracy and precision; (2) conducting volunteer testing where participants used and evaluated each test kit; and (3) comparing costs.

Laboratory accuracy ranged from 5.1–40.5% measurement error, with colorimeters the most accurate and test strip methods the least. Variation between laboratory and natural light readings occurred with one test strip method. Volunteer participants found test strip methods easiest and color wheel methods most difficult, and were most confident in the colorimeter and least confident in test strip methods. Costs range from 3.50–444 USD for 100 tests. Application of a decision matrix found colorimeters and test tube comparator kits were most appropriate for use in low-resource settings; it is recommended users apply the decision matrix themselves, as the appropriate kit might vary by context.

Microbial quality of domestic water: following the contamination chain in a rural township in Kenya

May 18, 2015 · 0 comments

Microbial quality of domestic water: following the contamination chain in a rural township in Kenya. Journal of Water, Sanitation and Hygiene for Development Vol 5 No 1 pp 39–49 © IWA Publishing 2015 doi:10.2166/washdev.2014.070

Authors: Pauline W. Macharia, Paul T. Yillia, Wairimu A. Muia, Denis Byamukama and Norbert Kreuzinger

A study was undertaken in Njoro Township, Kenya to evaluate the extent to which drinking water was subjected to post-collection faecal contamination in low-income and high-income households. Boreholes were the main drinking water sources, accounting for roughly 70% singular access. The microbial quality of drinking water from the boreholes deteriorated from the point-of-collection through conveying containers of small-scale water vendors to household storage containers, irrespective of their income status.

The densities of Escherichia coli (EC) were relatively low at the point-of-collection – median (M): 18 CFU/100 mL, range (R): 0–220, n = 60 – increasing considerably in the containers of water vendors (M: 290 CFU/100 mL, R: 30–350) and slightly (M: 360 CFU/100 mL, R: 0–520) between vendors and low-income households, many of whom used the services of vendors unlike high-income households who relied on a piped system on premises (M: 40 CFU/100 mL, R: 0–500). Post-collection contamination was high in low-income households compared to high-income households but differences were not significant between the two household categories with and without household water treatment (HWT).

Different HWT methods in the two household categories significantly reduced faecal contamination, but unhygienic handling and poor storage practices afterwards caused recontamination. HWT and behavioural change measures need not selectively target household groups solely on the basis of their income status.

Development of improved low-cost ceramic water filters for viral removal in the Haitian context

May 18, 2015 · 0 comments

Development of improved low-cost ceramic water filters for viral removal in the Haitian context. Journal of Water, Sanitation and Hygiene for Development Vol 5 No 1 pp 28–38 © IWA Publishing 2015 doi:10.2166/washdev.2014.121.

Authors: L. Guerrero-Latorre, M. Rusiñol, A. Hundesa, M. Garcia-Valles, S. Martinez, O. Joseph, S. Bofill-Mas and R. Girones

Household-based water treatment (HWT) is increasingly being promoted to improve water quality and, therefore, health status in low-income countries. Ceramic water filters (CWFs) are used in many regions as sustainable HWT and have been proven to meet World Health Organization (WHO) microbiological performance targets for bacterial removal (2–4 log); however, the described viral removal efficiencies are insufficient to significantly reduce the associated risk of viral infection. With the objective of improving the viral removal efficiencies of ceramic water filters, new prototypes with different oxide compositions and firing atmospheres have been developed and evaluated.

For removal efficiencies human adenoviruses, MS2 bacteriophage and Escherichia coli were quantified in all prototypes. A new model of CWF that was fired in a reductive atmosphere presented virus and bacteria removal efficiencies greater than 3.0 log and 2.5 log, respectively, which would fulfill the viral targets that are recommended by the WHO. Ceramic characterization of the selected filters, which were fired in a reductive atmosphere, showed that a larger specific surface area than those of control filters and higher fraction of a positive Z-potential fraction are the most likely explanations for this increase in virus removal.

Fouling in hollow fiber membrane microfilters used for household water treatment

May 18, 2015 · 0 comments

Fouling in hollow fiber membrane microfilters used for household water treatment. Journal of Water, Sanitation and Hygiene for Development In Press, Uncorrected Proof © IWA Publishing 2015  |  doi:10.2166/washdev.2015.206

Authors: Anna Murray, Mario Goeb, Barbara Stewart, Catherine Hopper, Jamin Peck, Carolyn Meub, Ayse Asatekin and Daniele Lantagne

The Sawyer PointOne hollow fiber membrane microfilter is promoted for household water treatment in developing countries. Critical limitations of membrane filtration are reversible and irreversible membrane fouling, managed by backwashing and chemical cleaning, respectively. The PointOne advertised lifespan is 10 years; users are instructed to backwash as maintenance. Owing to reduced turbidity and bacterial removal efficiencies, six PointOnes were removed from Honduran homes after 23 months of use. In the laboratory, we tested sterile water filtrate for turbidity and bacterial presence before and after backwashing and chemical cleaning. Sterile water filtrate from uncleaned filters had turbidity of 144–200 NTU and bacteria counts of 13–200 CFU. Cleaned filter effluent was positive for total coliforms.

On one new and one used, cleaned filter, we imaged membranes with scanning electron microscopy and characterized surface elemental compositions with spectroscopy. Images and spectroscopy of the used, cleaned membrane revealed a dense, cake fouling layer consisting of inorganic metal oxides, organic material, and biofouling. Burst fibers were visually observed. This PointOne was thus irreversibly fouled and non-functional after <2 years of use. Further research is recommended to determine: impacts of source water quality on PointOne performance, a cleaning regimen to manage fouling, and an appropriate filter lifespan.

Short- and Medium-Term Impacts of Household Water Supply and Sanitation on Diarrhea in Rural India

May 7, 2015 · 0 comments

The Short- and Medium-Term Impacts of Household Water Supply and Sanitation on Diarrhea in Rural India, April 2015. Maryland Population Research Center Working Paper.

Authors: Esther Duflo, Michael Greenston, Raymond Guiteras, Thomas Clasen.

Poor water quality and sanitation lead to severe health problems in developing countries, yet there is little evidence on the effectiveness of at-scale, infrastructure-based solutions for the rural poor. This paper estimates the impact of an integrated water and sanitation improvement program in rural India that provided household-level water connections, latrines, and bathing facilities to all households in approximately 100 villages. We employ an interrupted time-series analysis with multiple units to estimate the short- and medium-term impacts of the intervention on episodes of diarrhea for which treatment was received. The estimates suggest that the intervention was effective, reducing such episodes by 30-50%. These results are evident in the short term and persist for 5 years or more. The annual cost is approximately US$60 per household, as compared to annual household consumption of approximately US$740.

Susan Murcott: Getting the Right Products to Scale: Technology Evaluation for Water Filters

May 7, 2015 · 0 comments

Getting the Right Products to Scale: Technology Evaluation for Water Filters, By Susan Murcott, CITE Suitability Lead, MIT DUSP Research Engineer & D-Lab Instructor. Source: D-Lab, April 29, 2015.

Low-income consumers aspire to a better life that humanitarian products offer. International aid agencies, non-governmental organizations, governments and social entrepreneurs promote and disseminate millions of humanitarian products to alleviate poverty. But many of these products fail to deliver—either they fail to perform consistently, or if they survive in the marketplace, they fail to reach scale.

Rigorous product evaluations that are trusted, affordable and comprehensible are important preconditions to impact, sustained use, and scale. To meet this need, MIT launched the Comprehensive Initiative on Technology Evaluation(CITE), a five-year, USAID-funded project to develop a 3S Methodology, examining products’ suitability, scalability, and sustainability. This methodology has now guided two product evaluations to completion, one on solar lanterns in Uganda and another on household water filters in India.

In a recent session at the MIT Scaling Development Ventures conference, we presented our household water filter research in order to explore the challenges of rigorous product evaluation as well as the benefits and opportunities that it can create for development practitioners, users, and entrepreneurs to bring the best products to scale.

Our focal city for the evaluation was Ahmedabad, India, a city of 6 million people, comprised of all income classes, and the target populations were the poor, many of whom have been relocated in Ahmedabad from slums to subsidized, government-built, low-cost housing. This is a unique situation in which the poor have access to an “improved” water source, but it is of mixed water quality.

 

Infant and Young Child Faeces Management: Potential enabling products for their hygienic collection, transport, and disposal in Cambodia

May 1, 2015 · 0 comments

Infant and Young Child Faeces Management: Potential enabling products for their hygienic collection, transport, and disposal in Cambodia, 2015. WaterSHED; London School of Tropical Medicine and Hygiene.

Authors: Molly Miller-Petrie, Lindsay Voigt, Lyn McLennan, Sandy Cairncross, Marion Jenkins

Background – Despite evidence that children’s faeces play a major role in diarrheal disease transmission through the contamination of the household environment, relatively little priority has been given to research and interventions in this area. In Cambodia, only 20% of children’s faeces were disposed of in an improved sanitation facility according to the 2010 Demographic and Health Survey. This study explores current practices and the role that enabling products may play in increasing hygienic management practices.

Methods – A household survey was conducted in 130 houses in 21 villages and two provinces in Cambodia. Four focus group discussions were conducted, two in each province. Households were restricted to those with an improved sanitation facility and at least one child under five. Results were analysed using STATA13 and explanatory variables were tested individually and using logistic regression to control for child age. Focus group results were analysed qualitatively.

Results – Main place of defecation, method of moving faeces, and main place of disposal differed depending on child age, with children under two least likely to have their faeces disposed of hygienically. Overall, 62.7% of households reported using a hygienic main disposal site while 35.7% reported doing so consistently. Factors associated with hygienic disposal included the number of years a household had owned a latrine, the age of the caregiver, the consistency of adult latrine use, and the presence of tools for child faeces management in the latrine.

Discussion – The results demonstrate a need for interventions targeting the hygienic management of faeces of children under five in Cambodia, and particularly for children under two. The technologies most likely to facilitate hygienic disposal for these age ranges include reusable diapers, potties, and potentially latrine seats. Design features should ensure child safety, time-savings, cost-savings, ease of disposal, and ease of cleaning. Product marketing will also need to address hygiene behaviours related to child cleaning and caretaker hand washing to ensure reduction of disease transmission.

CO2 and H2O: Understanding Different Stakeholder Perspectives on the Use of Carbon Credits to Finance Household Water Treatment Projects

May 1, 2015 · 0 comments

CO2 and H2O: Understanding Different Stakeholder Perspectives on the Use of Carbon Credits to Finance Household Water Treatment Projects. PLoS One. 2015 Apr 30.

Summers SK1, Rainey R2, Kaur M3, Graham JP1.

1Department of Global Health, Milken Institute School of Public Health, The George Washington University, Washington, D.C., United States of America.
2United States Agency for International Development (USAID), Washington D.C., United States of America.
3Berkeley Air Monitoring Group, Berkeley, California, United States of America.

BACKGROUND: Carbon credits are an increasingly prevalent market-based mechanism used to subsidize household water treatment technologies (HWT). This involves generating credits through the reduction of carbon emissions from boiling water by providing a technology that reduces greenhouse gas emissions linked to climate change. Proponents claim this process delivers health and environmental benefits by providing clean drinking water and reducing greenhouse gases. Selling carbon credits associated with HWT projects requires rigorous monitoring to ensure households are using the HWT and achieving the desired benefits of the device. Critics have suggested that the technologies provide neither the benefits of clean water nor reduced emissions. This study explores the perspectives of carbon credit and water, sanitation and hygiene (WASH) experts on HWT carbon credit projects.

METHODS: Thirteen semi-structured, in-depth interviews were conducted with key informants from the WASH and carbon credit development sectors. The interviews explored perceptions of the two groups with respect to the procedures applied in the Gold Standard methodology for trading Voluntary Emission Reduction (VER) credits.

RESULTS: Agreement among the WASH and carbon credit experts existed for the concept of suppressed demand and parameters in the baseline water boiling test. Key differences, however, existed. WASH experts’ responses highlighted a focus on objectively verifiable data for monitoring carbon projects while carbon credit experts called for contextualizing observed data with the need for flexibility and balancing financial viability with quality assurance.

CONCLUSIONS: Carbon credit projects have the potential to become an important financing mechanism for clean energy in low- and middle-income countries. Based on this research we recommend that more effort be placed on building consensus on the underlying assumptions for obtaining carbon credits from HWT projects, as well as the approved methods for monitoring correct and consistent use of the HWT technologies in order to support public health impacts.

Contextual and sociopsychological factors in predicting habitual cleaning of water storage containers in rural Benin.

April 29, 2015 · 0 comments

Contextual and sociopsychological factors in predicting habitual cleaning of water storage containers in rural Benin. Water Resour Res, March 2015.

Authors: Andrea Stocker and Hans-Joachim Mosler

Recontamination of drinking water occurring between water collection at the source and the point of consumption is a current problem in developing countries. The household drinking water storage container is one source of contamination and should therefore be cleaned regularly. First, the present study investigated contextual factors that stimulate or inhibit the development of habitual cleaning of drinking water storage containers with soap and water. Second, based on the Risk, Attitudes, Norms, Abilities, and Self-regulation (RANAS) Model of behavior, the study aimed to determine which sociopsychological factors should be influenced by an intervention to promote habitual cleaning.

In a cross-sectional study, 905 households in rural Benin were interviewed by structured face-to-face interviews. A forced-entry regression analysis was used to determine potential contextual factors related to habitual cleaning. Subsequently, a hierarchical regression was conducted with the only relevant contextual factor entered in the first step (R2 5 6.7%) and the sociopsychological factors added in the second step (R2 5 62.5%).

Results showed that households using a clay container for drinking water storage had a significantly weaker habit of cleaning their water storage containers with soap and water than did households using other types of containers (b 5 20.10). The most important sociopsychological predictors of habitual cleaning were commitment (b 5 0.35), forgetting (b 5 20.22), and self-efficacy (b 5 0.14). The combined investigation of contextual and sociopsychological factors proved beneficial in terms of developing intervention strategies. Possible interventions based on these findings are recommended.

Factors Determining Water Treatment Behavior for the Prevention of Cholera in Chad

April 29, 2015 · 0 comments

Factors Determining Water Treatment Behavior for the Prevention of Cholera in Chad. Am Jnl Trop Med Hyg, April 2015

Authors: Jonathan Lilje, Hamit Kessely and Hans-Joachim Mosler

Cholera is a well-known and feared disease in developing countries, and is linked to high rates of morbidity and mortality. Contaminated drinking water and the lack of sufficient treatment are two of the key causes of high transmission rates. This article presents a representative health survey performed in Chad to inform future intervention strategies in the prevention and control of cholera. To identify critical psychological factors for behavior change, structured household interviews were administered to N = 1,017 primary caregivers, assessing their thoughts and attitudes toward household water treatment according to the Risk, Attitude, Norm, Ability, and Self-regulation model.

The intervention potential for each factor was estimated by analyzing differences in means between groups of current performers and nonperformers of water treatment. Personal risk evaluation for diarrheal diseases and particularly for cholera was very low among the study population. Likewise, the perception of social norms was found to be rather unfavorable for water treatment behaviors. In addition, self-reported ability estimates (self-efficacy) revealed some potential for intervention. A mass radio campaign is proposed, using information and normative behavior change techniques, in combination with community meetings focused on targeting abilities and personal commitment to water treatment.

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