The Swiss promoters of solar water disinfection (SODIS) believe this simple technique can be used effectively in emergency situations like the Indian Ocean tsunami disaster. Peter Kaufmann, head of the drinking water group at the Swiss Agency for Development and Cooperation (SDC), has recommended the use of SODIS in the areas affected by the tsunami. Tom de Veer, an experienced water engineer in disaster situations, doubts however if it is suitable in the first stage of an emergency.

SODIS involves filling clear plastic bottles with water, shaking them and then leaving them in the sun for at least six hours, if possible on a sheet of corrugated iron or a roof. The radiation from sunlight and the increased temperature of the water are enough to kill many forms of bacteria and viruses. Scientists at Switzerland’s Federal Institute for Environmental Science and Technology (EAWAG), who have been promoting SODIS for over a decade, say it is already in use in 20 countries. A project in Lombok, Indonesia, has reached 100,000 people within a year.

To make SODIS succeed you need a good local partner that is able to convince users that this simple technology works. You also need to convince engineers that if can be used safely in emergency situations.

Related news: EAWAG wins award for solar water cleansing, Source, 17 Dec 2004

Web site: Solar Water Disinfection, http://www.sodis.ch

Contact: Martin Wegelin, EAWAG/SANDEC, Switzerland, martin.wegelin@eawag.ch ; for contacts in Asia see the SODIS web site

Source: Swissinfo, 7 Jan 2005 ; Tom de Veer, personal contact, 12 Jan 2005

Tags: emergencies, water quality