Application of the software Defluoridation in the design of the groundwater defluoridation system using activated granular bone charcoal

Abstract

The water’s ingestion with high levels of fluoride causes a pathology called dental fluorosis, which results from the defective mineralization of the enamel matrix, directly associated with the ingested amount of water with high concentrations of fluorides. In this context, a defluoridation system by adsorption on bone activated carbon was developed, followed by contact precipitation through the addition of calcium and phosphorus salts. This system was constructed in a Poly Glass® tank with transparent high-density polyethylene coating, filled with 25 kg of bone activated charcoal of particle diameter equal to 20 x 50 mesh. For system designing, a software called Defluoridation was developed, which allows determining the system dimensions and the flow rates of reagent for the contact precipitation process. The system was applied in the groundwater treatment with fluoride concentration between 2.4 and 3.0 mg.L^-1. In total, 30,000 L of water were treated, of which 13,000 L by the adsorption technique, and then 7,000 L, which were filtered to reach values close to the raw water, and 10,000 L by the contact precipitation technique. The results obtained demonstrate the application efficiency of the Defluoridation software, emphasizing that the technique of contact precipitation is an economical and simple way for water supplying.