Defluoridation of Water With Activated Alumina

The fluoride ion is now recognized, both in this country and abroad, as a normal and frequently occurring constituent of natural waters. The latest figures available indicate that in this country there are over 600 public water supplies serving about 1,500,000 people with water containing this ion in concentrations in excess of 1.5 ppm (1). Despite this situation, at the present time, only two communities are known to be using equipment specifically installed for the purpose of removing excess fluorides from their water (2). This lack of application of preventive measures may be attributed to a number of factors most important of which are the high cost and complexity of operation of the fluoride removal processes. The methods of fluoride removal which have been tried or suggested may be divided into two basic types those based upon the addition of some material to the water during the softening or coagulation processes and those based upon an ion-exchange or adsorption process.