Operational experiences on small-scale community defluoridation systems

Excessive levels of fluoride in drinking water supplies is a major problem in the Rift Valley of Ethiopia. The methods of fluoride removal used by industrialized countries require more technical support for operation and maintenance than is possible in the rural areas of developing countries. There is a need for low cost defluoridation systems in areas with no alternative water sources. This paper describes three low cost water defluoridation methods that have been evaluated at pilot scale. Three villages with ground water with high fluoride content and relatively hot climate were considered. Techniques used are chemical precipitation by aluminium sulphate and lime, adsorption by bone char, and adsorption by clay minerals. Community support mechanisms that are useful to make such defluoridation systems sustainable and practical in the Ethiopian context were assessed. We recommend the aluminum sulfate and lime method to other fluoride affected areas, while developing further alternative techniques.