Bio-sand water filters save lives in Cambodia

By agency reporter
March 15, 2009

For Cambodians in rural Svay Rieng province, a little sand goes a long way in helping make water safe for consumption.

According to a report by humanitarian agency Church World Service, residents in 19 villages of Svay Rieng have been significantly reducing incidences of typhoid and diarrhoea by drinking water filtered through affordable, user-friendly bio-sand filter devices small enough to place in a home or office space.

CWS has provided 1,216 of the filters to date in 56 Svay Rieng villages for use by people in some 1,900 households, schools, pagodas and commune halls. The effort is part of a Water and Sanitation Co-operation Project by Church World Service Cambodia that has benefited thousands of the poorest and most vulnerable people in remote rural areas.

The simple bio-sand water filters are a lifeline in a country where it's estimated that 74 percent of all deaths come from water-borne diseases. Despite advances in recent years made by Cambodia's public water utility in converting Phnom Penh's war-degraded water supply system into a safe-water utility serving the capital city, rural areas of Cambodia still suffer from lack of clean water, sanitation resources, and related hygiene awareness and education.

Given the region's soaring inflation and the effect of the global financial meltdown on funding to aid agencies, bio-sand water filters are proving a more affordable option for rural water problems than are larger, community well constructions.

Church World Service staff in Cambodia had initially planned to provide a certain number of wells and latrines in the Svay Rieng communities they serve, but couldn't justify suppliers' escalating prices for materials. Instead, they reduced the number of wells and latrines on their list and increased the number of much cheaper bio-sand water filters.

The cost for a typical bio-sand filter can range from US$15 to $20, depending on regional costs for materials. In the CWS programme, those who receive the filters are encouraged and given training to build their own filter devices.

Bio-sand filters are compact, household-sized box devices, usually built on a concrete base, containing a layer of gravel topped by a layer of sand. When water is poured through the top of the device, it's filtered by the sand and gravel. But it's the shallow layer of water remaining on top of the sand which forms a biologically dynamic wet film, or 'Schmutzdecke', that makes the critical difference-by trapping and consuming the micro-organisms and contaminants in the water. The filtered water flows out through a pipe at the base of the device into a clean container for safe consumption.

Developed in 1990, bio-sand filters are increasingly being used by humanitarian agencies in developing countries. Research indicates that under optimal operating conditions and maintenance, bio-sand filters can remove most worms and parasites, E.coli. iron, manganese and other toxicants from contaminated water.

Church World Service is a non-governmental organisation that has had relief and development offices in Cambodia since 1979. It was one of the first aid agencies permitted to work there after the fall of the Khmer Rouge. In 2005 CWS launched its comprehensive water, sanitation, health and hygiene cooperation project for vulnerable, residents in two Svay Rieng districts near the Cambodia-Vietnam border, in partnership with Cambodia's Provincial Departments of Rural Development (PDRD). The effort is part of the CWS international Water for All initiative.

Bio-sand water filters are fast becoming star offerings. In Thmei Village, about 400 villagers including women, teachers and 1,384 students at Kokir Primary School, attended trainings on bio-sand filter use and maintenance and clean water and sanitation practices.

Church World Service staff subsequently monitored 156 households and found that those drinking water from the filters experienced a significant decrease in diarrhoea and typhoid, according to CWS Cambodia Country Representative Josephine Barbour.

In village commune halls, the water filters are available to everyone. Reports one commune hall clerk, "Now our commune stop [sic] buying pure drinking water from the market. When we organize meetings or other events, we can use filtered water. So we can save some money for other purposes."

Villagers provided with bio-sand filters have spread the word about the dangers of drinking contaminated water and other poor hygiene practices and, at the request of their neighbours, are sharing their water filters like a fountain of life.

CWS, which also conducts agriculture, education and livelihoods development programs throughout Cambodia in co-operation with local partners, now plans to expand its water and sanitation program in 20 more villages.

Church World Service is an international relief, development, refugee protection and advocacy agency funded by public donations, grants and through the support of 35 Protestant, Orthodox and Anglican denominations in the USA.

Contributions that will help bring clean water and other self-help assistance to families and communities around the world can be made online at:

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