A conceptual overview on sustainable technologies for the defluoridation of drinking water

Water is precious to us, as it supports every spheres of human life. The increasing reports on pollution of this sacred resource from different sources show our scant regard to this pivotal issue. People in more than 35 nations across the globe face issues of excess fluoride in drinking water, the intensity and severity of which varies with the environmental settings in terms of their geographical and economical status. It has been observed that very few proven sustainable options are available for fluoride removal, especially in developing countries, where the impact of the issue is highly intense. Though the considerable amount of research undertaken worldwide has thrown up many technologies, each having its own advantages and limitations, a lasting solution is still at large. The coagulation and adsorption/ion-exchange processes are the most widely opted defluoridation techniques practiced in fluoride-endemic areas. The Nalgonda technique and adsorption by bone char, or a combination of both, have been used in many developing countries like India and Tanzania, at both domestic and community levels. The membrane processes assure good quality water, but are higher technology and higher cost options for most of the fluoride-endemic nations. Electrochemical techniques are energy-intensive options but offer excellent fluoride removal. However, the lack of concise conceptual reviews is visibly felt in defluoridation research, which prompted us to carry out this study. This article highlights the underlying basic principles and processes involved in existing fluoride removal technologies so as to catalyze further research in this area.