Improvement of User Friendliness of a Simple Domestic Defluoridation Unit Using Activated Alumina

The user friendliness of an Activated Alumina (AA) based fluoride filter using a ceramic cartridge, and locally available food grade containers has been improved by using two ceramic cartridges. The ceramic cartridge serve the dual purposes of filtering out any suspended particles and providing enough contact time for the AA to absorb the fluoride from water. The fluoride filter has a flow rate of 3 lit./hr a marked improvement from 1.7 lit./hr. achieved with one ceramic cartridge. These filters have been tested in laboratory using fluoride contaminated ground water from a nearby village. The filter yielded a safe volume of 1300 lit. water (<1.5 ppm fluoride in outlet water) with a Specific Safe Water Yield of 520 mg/kg of AA and Fluoride Uptake Capacity of 863.2 mg/kg AA. The cost of the defluoridated water for the first cycle is Rs. 0.87/lit. which includes the cost of the filter and the AA. The recurring cost of operating the filter, if the AA is to be discarded after single use, is quite low at Rs. 0.22/lit. With a water usage of 20 litres per day for a family of four, no maintenance is required in form of regeneration of the AA bed before two months five days with an inlet fluoride conc. of 2.41 ppm. and Simplicity of design and easy fabrication makes this fluoride filter suitable for replication. Keywords: Activated Alumina, defluoridation, fluoride, filter