Health Stream Literature Summary - Issue 56 - December 2009

Sustained use of a household-scale water filtration device in rural Cambodia.
Brown, J., Proum, S. and Sobsey, M.D. (2009) Journal of Water & Health, 7(3); 404-412.

Point-of-use water treatment is increasingly being promoted as a means of increasing global access to safe drinking water, however there is little information on the sustainability of this water treatment intervention after the initial implementation efforts and in the absence of monitoring by external parties. The ceramic water purifier (CWP) is an emerging point-of-use water treatment technology which uses a locally produced household-scale, porous ceramic filter. These filters are supported by a number of published and unpublished studies which indicate their microbiological effectiveness and impacts on user health, including a randomised, controlled trial in Cambodia which found substantial reduction in diarrhoeal diseases in users versus non-users. There have been an estimated 100,000 CWPs distributed in Cambodia since 2002, however no data exist on the percentage still in use. This study aims to assess whether and how long filters were successfully used after initial interventions and what factors contributed to their long-term use in households.

The filters were originally implemented as part of NGO-subsidised distribution programs over four years from 2002 to 2006 in three provinces of Cambodia; in Kampong Chhnang and Pursat provinces from July 2002 and in Kandal province from December 2003. Complete lists of households who received filters in the three project areas as part of the original interventions were compiled and households were selected using a random numbers table. There were 506 households in 13 rural villages that could be located and consented to participate in the survey. Household visits occurred during February and March 2006. The data collection team determined whether the filter was in current use, i.e., the filter was in good working order, it contained water or was damp from recent use and one or more household members reported daily use for the production of drinking water. Time in use for each filter was established on the basis of the manufacturing date stamped on the filter, delivery date, or through user interviews. A questionnaire was administered to the adult female who was the person generally charged with water collection and management for the household. Information was collected on basic household demographics, household water handling and use, sanitation, health and hygiene behaviours and other factors thought to be related to CWP adoption and use. Socio-economic status was gauged based on income and a wealth index measure. Data was collected on the method of gathering water from the household storage container and on the presence of soap in the household via demonstration to the interviewer.

Ceramic water filters were more likely to be used by households that already have some knowledge of safe water, sanitation and hygiene practices. Positive associations with filter use were observed for households which had access to own or shared latrine (OR: 2.4, 95% CI 1.5-4.0), the household caregiver reported that she or he always washed hands with soap and water at critical points such as after defecating or before preparing food (OR: 1.6, 95% CI 1.0-2.6) and the presence of soap in the household (OR:1.7, 1.0-3.0), after controlling for time since implementation. Households that had purchased the technology (OR: 2.1, 95% CI 1.2-3.7) were more likely to be still using filters versus those receiving the filter for free. Use of a surface water source for drinking water was positively associated with continued filter use (OR: 1.7, 95% CI 1.1-2.7) and households that reported groundwater use from deep wells (greater than or equal to 10 m) were less likely to use the filter (OR: 0.38, 95% CI 0.18-0.79) after controlling for time since implementation.

Among the 506 households in the survey, 350 were not using filters at the time of interview and 328 of these provided responses when asked why their filter was not used. The majority (65%) cited breakage of the ceramic filter element, the spigot or the container. This suggests that the availability of replacement parts and access to or awareness of distribution points may limit the sustainability of this ceramic filter intervention. Filters were in use for about 2 years, on average before disuse. There was a strong association between filter use and time since implementation. Logistic regressions indicated a declining odds of 44% every 6 months of finding a filter still in use (OR: 0.56, 95% CI 0.50-0.63). An average fall-off in use of approximately 2% per month after implementation was calculated, largely owing to breakages.

The uptake and long-term use of the ceramic water purifier in Cambodia can be enhanced by having greater availability and accessibility of spare parts, especially the ceramic filter elements themselves. Despite the declining use of the intervention, user satisfaction with the filters was generally very high and there were a high percentage of users who reported a willingness to purchase additional filters or replacement parts.

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