WEDC – An engineer’s guide to domestic water containers

February 9, 2012 · 0 comments

An engineer’s guide to domestic water containers, 2011.

Text by Brian Reed, with contributions from Rebecca Scott, Brian Skinner and Tricia Jackson.

WEDC.

This booklet examines the range of domestic water containers commonly found in low-income countries and explores the role that water containers have in ensuring that household water supplies are adequate and safe. It also explains why planning for a water supply system should not end at the public tap or village well but extend to the place where the water is used. Understanding the ways in which people use water containers and designing the supply system to take account of this will help engineers to provide a better and safer service.

Contents of this booklet
Introduction …………………………………………..1
Uses of water containers …………………………1
Design of containers ………………………………5
Containers for anal cleansing ………………… 14
Water containers for handwashing …………. 14
Treatment systems ………………………………. 16
Maintenance ………………………………………. 18
Water point design ………………………………. 18
Summary……………………………………………. 18
References …………………………………………. 19

A systematic approach to behavior change interventions for the water and sanitation sector

February 7, 2012 · 0 comments

Int J Environ Health Res. 2012 Jan 31.

A systematic approach to behavior change interventions for the water and sanitation sector in developing countries: a conceptual model, a review, and a guideline.

Mosler HJ. Eawag, Swiss Federal Institute of Aquatic Science and Technology,Ueberlandstrasse 133 , 8600 , Duebendorf , Switzerland.

Public health practitioners increasingly agree that it is not enough to provide people with water and sanitation hardware. Numerous approaches are used to tackle the “software” which means to ensure behavior change necessary to come along with the sanitation hardware. A review of these approaches reveals several
shortcomings, most importantly that they do not provide behavioral change interventions which correspond to psychological factors to be changed.

This article presents a sound psychological model, which postulates that for the formation of new habitual behavior, five blocks of factors must be positive with regard to the new behavior: risk factors, attitudinal factors, normative factors, ability factors, and self-regulation factors. Standardized tools for measuring the factors in face-to-face interviews are presented, and behavioral interventions are provided for each factor block. A statistical analysis method is presented, which allows the determination of the improvement potential of each factor.

Prediction of child health by household density and asset-based indices

February 7, 2012 · 0 comments

Am J Trop Med Hyg. 2012 Feb;86(2):280-91.

Prediction of child health by household density and asset-based indices in impoverished indigenous villages in rural Panama.

Halpenny CM, Koski KG, Valdés VE, Scott ME.

Institute of Parasitology and McGill School of Environment Macdonald Campus of McGill University, Ste-Anne de Bellevue, Quebec, Canada; School of Dietetics and Human Nutrition, Macdonald Campus of McGill University, Ste-Anne de Bellevue, Quebec, Canada; Escuela de Nutrición y Dietética, Facultad de Medicina,
Universidad de Panamá, Panamá City, Panamá

Chronic infection over a 16-month period and stunting of preschool children were compared between more spatially dense versus dispersed households in rural Panamá. Chronic protozoan infection was associated with higher household density, lower household wealth index, poor household water quality, yard defecation, and the practice of not washing hands with soap before eating.

Models for chronic diarrhea confirmed the importance of household wealth, water quality, sanitation, and hygiene practices. Furthermore, chronic protozoan infection was an important predictor for low height-for-age, along with low household wealth index scores, but not household density. Thus, despite better access to health related infrastructure in the more densely populated households, chronic protozoan infection was more common, and was associated with higher rates of child stunting, compared with more dispersed households.

Evaluation of the Solar Water Disinfection Process (SODIS) Against Cryptosporidium parvum

February 7, 2012 · 0 comments

Am Jnl Trop Med Hyg Feb 2012

Evaluation of the Solar Water Disinfection Process (SODIS) Against Cryptosporidium parvum Using a 25-L Static Solar Reactor Fitted with a Compound Parabolic Collector (CPC)

María Fontán-Sainz, Hipólito Gómez-Couso, Pilar Fernández-Ibáñez and Elvira Ares-Mazás*

Address correspondence to Elvira Ares-Mazás, Laboratorio de Parasitología, Facultad de Farmacia, Campus Universitario Sur, 15782 Santiago de Compostela, A Coruña, Spain. E-mail: melvira.ares@usc.es

Water samples of 0, 5, and 30 nephelometric turbidity units (NTU) spiked with Cryptosporidium parvum oocysts were exposed to natural sunlight using a 25-L static solar reactor fitted with a compound parabolic collector (CPC). The global oocyst viability was calculated by the evaluation of the inclusion/exclusion of the fluorogenic vital dye propidium iodide and the spontaneous excystation. After an exposure time of 8 hours, the global oocyst viabilities were 21.8 ± 3.1%, 31.3 ± 12.9%, and 45.0 ± 10.0% for turbidity levels of 0, 5, and 30 NTU, respectively, and these values were significantly lower (P < 0.05) that the initial global viability of the isolate (92.1 ± 0.9%). The 25-L static solar reactor that was evaluated can be an alternative system to the conventional solar water disinfection process for improving the microbiological quality of drinking water on a household level, and moreover, it enables treatment of larger volumes of water (> 10 times).

Feb 3 – WASHplus Weekly: 10 Studies on HWTS Published in 2011

February 3, 2012 · 0 comments

WASHplus Weekly: 10 2011 Studies on HWTS

Feb 3, 2012 – This WASHplus Weekly contains 10 household water treatment and safe storage studies published in 2011. A number of HWTS technologies are reviewed, including studies on the technical performance of slow sand filtration, Moringa seeds, and Biosand filters. Studies from Bolivia, Malawi, and Rwanda investigate the behavioral and cultural aspects that influence the adoption and use of HWTS by communities. In addition to the 10 studies, links to two previous Weekly issues on HWTS and a listing of HWTS-related websites are included.

Household decisions and child health: Estimating the links between water treatment and the incidence of diarrhea

February 1, 2012 · 0 comments

Household decisions and child health: Estimating the links between water treatment and the incidence of diarrhea using non-recursive two-equation causal models, 2012.

Carlos Antonio R. Tan, Jr. and Joseph J. Capuno. University of the Philippines.

The treatment of drinking water is advocated to reduce the incidence of child diarrhea. However, evaluating the impact of water treatment with only observational data leads to biased estimates since it could be the occurrence of child diarrhea that induced the household to treat their drinking water. To deal with the possible simultaneity between the treatment of drinking water and the incidence of child diarrhea, we specify non-recursive two-equation causal models and apply it on a sub-sample of households with children below five years old from the Philippine National Demographic and Health Surveys.

In the treatment effects model, we find that the treatment of drinking water reduces by 5.2 percentage points the proportion of under-5 children afflicted with diarrhea. In the instrumental-variable probit model, we find that households have a higher propensity to sterilize their drinking water by 1.2 percentage points given a one percentage point increase in the proportion of under-5 children with diarrhea. Ignoring the simultaneity yields the misleading result that water treatment increases the incidence child diarrhea. These results underscore the need to insure the quality of drinking water at the point of use and not just at the point of source.

Assessing the Implementation of Selected HWTS Methods in Emergency Settings

January 31, 2012 · 0 comments

Assessing the Implementation of Selected Household Water Treatment and Safe Storage Methods in Emergency Settings, 2011.

Daniele Lantagne, Thomas Clasen. London School of Hygieneand Tropical Medicine

We were commissioned by UNICEF and Oxfam to undertake this study to address two overarching questions:

  • 1) What role, if any, should household water treatment and safe storage (HWTS) play in emergency response (in other words, is HWTS a necessary, effective, and suitable intervention for protecting people affected by emergencies compared to other possible interventions)?; and,
  • 2) What are the factors, if any, associated with feasible, and potentially sustained, implementation of HWTS in response to emergencies (e.g., type of emergency, characteristics of setting and affected population, capacity of responders, types of interventions, nature of programmatic support)?

We focused particularly on evaluating HWTS interventions implemented in the acute emergency context, within eight weeks of emergency onset.

To answer these questions, we investigated HWTS implementations in four acute emergency contexts between August2009 and March 2010, including:

  • 1) a cholera outbreak in Jajarkot, Nepal;
  • 2) an earthquake in West Sumatra,Indonesia;
  • 3) a flooding event during a cholera epidemic in Turkana, Kenya; and,
  • 4) an earthquake that causedsignificant internal displacement in Haiti.

These emergencies represented a diverse range of emergency situations, geographical settings, affected population size, and HWTS implementation strategy. In each emergency we conducted the following activities:

  • 1) spatial analysis;
  • 2) household surveys;
  • 3) water quality testing;
  • 4) qualitative interviews with water, sanitation, and hygiene (WASH) responders and logistical staff; and,
  • 5) data collection to characterize response costs.

Evaluating household water treatment options: health-based targets and microbiological performance specifications

January 31, 2012 · 0 comments

Evaluating household water treatment options: health-based targets and microbiological performance specifications, 2011.

WHO

Properly formulated and locally relevant performance specifications are needed to protect users and inform decision-making regarding selection of technologies or approaches. This document provides a basis by which to evaluate the microbiological performance of HWT options by:

  • establishing a series of health-based microbiological performance targets, ranging from an interim target to highly protective, to encourage incremental improvements in water safety (sections 2 and 3 and Appendix 1); and
  • providing guidance to inform the development of new HWT testing protocols or supplement existing protocols (Appendix 2).

It also describes additional factors, including:

  • those pertaining to national-level technology evaluation or verification programmes (Appendix 3); and
  • justification for use of quantitative microbial risk assessment (QMRA) and performance targets for three classes of pathogens (Appendix 4)

WaterSHED Asia – Consumer preferences and uptake of household water treatment products in Cambodia

January 31, 2012 · 0 comments

Impact of a natural coagulant pretreatment for colour removal on solar water disinfection

January 30, 2012 · 0 comments

Journal of Water, Sanitation and Hygiene for Development | 01.1 | 2011

Impact of a natural coagulant pretreatment for colour removal on solar water disinfection (SODIS)

Sarah A. Wilson and Susan A. Andrews

Solar water disinfection (SODIS) is the process of treating microbiologically contaminated water in clear plastic bottles through exposure to sunlight. One of the major limiting factors of this treatment is source water quality. This work investigates the impact of source water colour on SODIS efficiency and evaluates a natural coagulant for colour removal. The ability of Moringa oleifera seed emulsion to both clarify and decolourize source waters was investigated as a coagulation pretreatment for SODIS.

This coagulant reduced the colour by more than two-thirds and achieved up to 1-log10 bacterial removal (90%). The combined Moringa oleifera coagulation-SODIS treatment sequence was tested in highly coloured natural source water and was found to reduce the sunlight exposure time required by up to 2 hours. However, despite being an effective clarification and decolouring process, the pretreatment may not shorten the overall treatment time because of its own labour and time requirements, potentially decreasing the treatment compliance rates. In addition, while total coliform and heterotrophic bacteria regrowth was observed during overnight storage of the treated water, no Escherichia coli regrowth was found to occur.

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