A WATER-purification program by the Church World Service is providing clean water to thousands of rural Cambodians in Svay Rieng province using simple but effective technology, the group said.

The Church World Service says it has provided 1,200 filters for use by some 1,900 household, schools, pagodas and commune halls in 56 villages in Svay Rieng, and that the program has significantly reduced incidences of typhoid and diarrhoea by providing villagers sand-filter devices small enough to place in a home or office.

Produced at low costs - between US$15 and $20  - bio-sand filters are compact box devices usually built on a concrete base and containing a layer of gravel topped by a layer of sand.

Water poured through the top of the device is filtered by the sand and gravel. A shallow layer of water remaining on top of the sand forms a wet film that traps and consumes 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.