The engineering company RWB (in Porrentruy, Canton of Jura) has devised a water filtration system that uses no electricity or added chemicals. Used successfully in mountainous areas in Switzerland, this solution has promise for applications in emerging countries.

RWB Groupe is an engineering company active mainly in the field of water management and water treatment. First used in 2002, the KLS filter was designed by the group’s vice-chairman Daniel Urfer. It is manufactured in partnership with the Swiss company Etertub. The KLS filter can be used to treat water in remote locations that are not connected to a drinking water system. It removes all undissolved particles including bacteria and suspended matter effectively without the need for electricity or chemicals, by means of a device that is easy to maintain.

Initially developed to treat around 5,000 litres a day (the water consumption of a medium-sized farm or a small hamlet), the system is now also available in a more compact version capable of filtering between 500 and 700 litres a day, suitable for a mountain hut, a remote chalet or remote dwelling for example. The largest installations can treat up to 30,000 litres a day.

A solution with promise for developing countries

The device makes use of tried-and-trusted gravel-filtration and slow-sand-filtration technology. But what make the KLS filter unique is its use of bauxite, and RWB has filed a patent for its design. Around 20 KLS filters are currently in use in Switzerland, mainly in mountainous regions. These installations are used in most cases to treat water from private springs that is otherwise unfit for consumption. The device is also useful for treating contaminated rainwater from rooftops which has a very low mineral content.

The future of the KLS in new markets is already becoming clear, and in sustainable development the KLS filter is showing most promise in applications abroad. Two filters have already been installed in Africa, one in Burkina Faso and the other in Guinea, to tackle the major problems of water turbidity and contamination by pathogenic microorganisms. “To provide a truly sustainable solution, ideally we should manufacture locally for the local market,” says Daniel Urfer, who would like to see this technology becoming fully transferable. This sustainable aspect is very important to RWB, which wants to see guaranteed access to drinking water for all at an affordable cost. “We are first and foremost scientists who believe that the most important thing is to provide concrete solutions.”