Alternatives for removing fluoride from water for human consumption and water for reuse

This compilation aims to describe the studies carried out focusing on the treatment of 100-127 mg/L of wastewaters involving different fluoride removal alternatives which demonstrated efficacy. Adsorption by bone char, both in batch as in continuous systems, including chemical and thermal regeneration of the adsorbent, composed of apatite in its structure (70-76%) is highlighted. Bone char showed an adsorption capacity of 6.8 mg/g, well fitted by the Freundlich model and being able to be regenerated until five cycles using NaOH solution. Using a monopolar configuration with 8 aluminium electrodes and current density of 7.53 mA/cm2 during 60 min of electrocoagulation, a treated stream containing 1 mg/g (pH of 6-6.5) or 36 mg/L (without pH control) have been obtained. An using the most conventional treatment, precipitation with calcium sources, 60 min of reaction with the use CaCl2 was able to reduce the fluoride concentration from 139 mg/L to 8 mg/L using CaSO4 the concentration was reduced to 12 mg/L, that was further decreased to 10 mg/L, after 24 hours, without agitation. Then, the process to be chosen depends on the facilities and chemicals available and also the requirements of specific treated stream downstream.