SODIS - an arsenic mitigation option?

About 95% of the population in Bangladesh is supplied by groundwater from five million wells. Several survey programmes revealed that arsenic might be found in three million wells affecting up to 70 million people. Currently, alternative water resources and water treatment processes for the arsenic removal are being developed. One considered option is to return from the groundwater to surface water which, however, in most cases is not safe for consumption and, therefore, requires disinfection. SODIS (Solar Water Disinfection) is a simple and lowcost water treatment method to improve the microbiological quality of drinking water at household level. PET plastic bottles are filled with polluted water and exposed to sunlight for 1 day. The microorgansisms are inactivated by the UV-A radiation and the increased water temperature. SODIS applied world-wide is described in www.sodis.ch and has been field tested in Bangladesh to study its effciency and socio-cultural acceptance.