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Low-tech Clay Filters Cut Disease

KALUTARA, 1 July 2008 (IRIN) – For thousands of Sri Lankans without easy access to potable water, a low-tech filter has provided them with a convenient source of safe water, saving on fuel costs and cutting disease.
The water filter was first mass-produced in Nicaragua and used in emergency relief operations. It is essentially a clay pot fortified with ground paddy husk and coated with colloidal silver that strains out virtually all harmful bacteria and parasites.

The American Red Cross (ARC) began production of the clay filter in Sri Lanka in January 2007 and has distributed some 10,000 units so far, principally to survivors of the December 2004 tsunami that devastated 13 of the island's 25 districts.

"Our aim is to provide a point-of-use water purification solution that is low cost and user friendly to as many Sri Lankans as possible," Omar Rahaman, ARC's social marketing adviser for the project, told IRIN. He added that the filter had benefited an estimated 50,000 Sri Lankans so far.

Ease of access

HK Nirosha, a resident of the western Kalutara District, who lost her home in the tsunami, said her biggest problem is the arduous daily trek down a steep hill to draw water.

Nirosha's family was given accommodation by the government in a community housing scheme in Rosawatte, Kalutara, three years ago. "I'm grateful that we were given this house, but the biggest problem we have is that we have no water supply," she said. An artesian well installed near her two-room dwelling spewed water tainted with a reddish sediment that residents are reluctant to use even for bathing.

Like the 68 other families in her housing project, she was given a water filter by ARC as a stop-gap solution. She still has to make the daily trudge to a well that has reasonably clear water, but all she does now is top up the water filter to have a ready supply her three-year-old son and one-year-old daughter can safely consume.

In a neighbouring house, WP Sharmalie was busy toting brimming containers of rainwater that had collected overnight. "I'm very careful to keep the filter in good condition because we give my grand-daughter, who is only six months old, water from it," she said. Previously, drinking water was rigorously boiled and the firewood was expensive.

Photo: Christine Jayasinghe/IRIN
A worker puts the finishing touches to a water filter made of clay and paddy husk at a factory in Kelaniya, a suburb close to the Sri Lankan capital Colombo

Preventing disease

Water-borne diarrhoeal disease is a leading cause of malnutrition and under-nutrition, Renuka Jayatissa, medical specialist in charge of nutrition at the UN Children's Fund, UNICEF, told IRIN. "As long as there are specific results to show that the filter provides safe water, any attempt that will help control diarrhoea can only be a good thing."

"After the filters are given to beneficiaries, we have a strict procedure for testing the water quality," said Jayanath Wijenayake, information and education field supervisor of the Sri Lanka Red Cross Society (SLRCS). He showed IRIN a bacteriological field testing kit that is used during follow-up visits.

The clay filter, which holds eight litres of water, is encased in a plastic receptacle with a tap at its base. Visits by SLRCS personnel, who work in partnership with ARC in implementing projects, ensure that recipients install and maintain the filter correctly.

With one manufacturing plant turning out some 1,000 clay filters a month, the ARC is gearing up to increase production by contracting another pottery factory to produce double the number.

Master potter Walter Pothmitiyage oversees the process, at the factory in Kelaniya, a suburb of the capital Colombo. It is necessarily slow because each pot needs to be air-dried for 10 days and then tested for appropriate porosity. ARC has equipped the Kelaniya factory with a clay mixer, hydraulic press and other equipment for the custom-made filters.

So far, ARC has distributed the water filters for free, but intends to make them available at an affordable price to wholesale or retail buyers. "We are now ready for business," said Rahaman, who sees great potential for the filters throughout Sri Lanka where access to safe drinking water is an ongoing problem. "The challenge is to make the transition from a project to an enterprise," that can self-finance the production of additional clay filters.

The filter, based on ancient water-purifying technology, was first mass-produced by the NGO, Potters for Peace, in 1998 for people affected by Hurricane Mitch. More than 30,000 beneficiaries in Central America, West Africa and South and Southeast Asia now use the filter.

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