The following processes are used for fluorine removal:
1. filtration through activated alumina- this is the most widely used process
2. coagulation-flocculation – or aluminum sulphate treatment - can only be used on raw water that requires sedimentation and that has low fluoride content.
3. lime used to soften water -This method can be used but with a pH >10 and provided that the water has a sufficient magnesium level (high) because it is the magnesium oxide that will adsorb the fluorine. Approximately 50 mg · L–1 of magnesium is required to remove 1 mg · L–1 of fluorine.
4. using tricalcium phosphate
5. other processes
· reverse osmosis
· Electrodialysis