How to remove fluoride from groundwater?

Hello everyone! Here in Brazil, São Paulo State and near regions some wells (mostly tube wells) which are 80 to 400 m deep has high concentration of Fluoride (F-), between 3 to 15 mg/l of F-, specially in the drought periods, when the water replacement in the aquifers is low. So, what can be the solution? Reverse Osmosis? Electrode-ionization? Ion Exchange?  The solution that we use is use of low electric current electrolysis for capturing the fluoride in the electrode.We found this is a quick and cheap process for treating the fluoride water. But I would like to hear from water treatment fellows, if they have other solutions which are quicker and economical. Regards!