Defluoridation of drinking water using baked clay.

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University of Dar es Salaam
In different parts of the world endemic fluorosis is a severe problem. This problem is due to excessive fluoride concentration in the drinking water. In Tanzania, it has been noted that in certain areas, the northern part especially, the fluoride concentration exceeds the World Health Organization (WHO) standard of 1.5 mgF- /1 and in some places even the Tanzania temporary standard of 8.0 mgF- /1. Water treatment for removal of fluoride is not generally simple and cheap. The methods used in industrialised countries require more technical support for operation and maintenance than is possible in the rural areas of developing countries. In this study a method of removing or reducing excess fluoride from drinking water using a locally available material (clay) has been investigated and the results obtained are ecouraging. Several factors influence the removal capacity. A proper temperature at which the clay should be baked is essential. Good removal efficiencies are achieved in acidic conditions, and when the initial fluoride concentration in raw water is low. In batch and flow experiments there are also a favourable reaction time and grain size of clay. The reaction between the fluoride and clay raises the pH considerably which raises the technological question for domestic use. But the removal efficiency found is a substantial increase in the results previously found and encouraging for further work on the method.
Water, Fluoridation, Purification
Wambede, J. T. (1994). Defluoridation of drinking water using baked clay. Masters dissertation, University of Dar es Salaam. Available at (