Table 4 - Commonly applied methods for removal of fluoride from drinking water (after Heidweiller, 1990; Jagtap et al., 2012; Mohapatra et al., 2009; Sandoval et al., 2021; Van der Bruggen et al., 2008).
| Treatment method | Capacity/dose | Working pH | Interferences | Advantages | Disadvantages | Relative cost |
| Coagulation | ||||||
| Alum (aluminium sulphate) | 150 mg/mg F | Non-specific | - | Established process | Sludge produced, treated water is acidic, residual Al present, may have adverse taste | Medium-high |
| Lime | 30 mg/mg F | Non-specific | - | Established process | Sludge produced, treated water is alkaline, may have adverse taste | Medium-high |
| Alum + lime (Nalgonda) | 150 mg alum + 7mg lime/mg F | Non-specific, optimum 6.5 | - | Low-tech, established | Sludge produced, high chemical dose, residual Al present, may have adverse taste | Medium-high |
| Gypsum + fluorite | 5 mg gypsum + < 2 mg SO4 /mg F | Non-specific | - | Simple | Needs trained operators, low efficiency, high residual Ca, SO4 | Low-medium |
| Calcium chloride | 3 mg CaCl2/mg F | 6.5-8.0 | - | Simple | Needs additional flocculent (e.g., FeCl3) | Medium-high |
| Electrochemical | ||||||
| Electrocoagulation | High | 6.0-8.0 | Sulphate, phosphate, bicarbonate | Few chemicals | Needs electrode replacements, power; passivated film formation, potential residual Al in treated water | Medium-high |
| Adsorption/ion exchange | ||||||
| Activated carbon | Variable | < 3 | Many | - | Large pH changes before and after treatment | High |
| Plant carbon | 300 mg F/kg | 7 | - | Locally available | Requires soaking in potassium hydroxide | Low-medium |
| Zeolites | 100 mg F/kg | Non-specific | - | - | Poor capacity | High |
| Defluoron 2 | 360 g F/m3 | Non-specific | Alkalinity | - | Disposal of chemicals used in resin generation, Cl in treated water | Medium |
| Clay pots | 80 mg F/kg | Non-specific | - | Locally available | Low capacity, slow | Medium |
| Activated alumina | 1200 g F/m3 | 5.5 | Alkalinity | Effective, well-established | Needs trained operators, chemicals not always available | Medium |
| Bone | 900 g F/m3 | > 7 | Arsenic | Locally available | May give taste, degenerates, not universally accepted | Low |
| Bone char | 1000 g F/m3 | > 7 | Arsenic | Locally available, high capacity | Not universally accepted, may give adverse color, taste | Low |
| Membrane techniques | ||||||
| Electrodialysis | High | Non-specific | - | Can remove other ions, used for high salinity, no chemicals | Skilled operators, high cost, membrane fouling | Very high |
| Reverse osmosis | High | Non-specific | - | Can remove other ions, used for high salinity, no chemicals | Skilled operators, high cost, membrane fouling, can remove beneficial solutes, residual saline wastewater | Very high |
| Nanofiltration | High | Non-specific | - | Can remove other ions, no chemicals | Skilled operators, high cost, membrane fouling, can remove beneficial solutes, residual saline wastewater | Very high |