Design and optimization of an electrocoagulation reactor for fluoride remediation in underground water sources for human consumption

• Published in: Journal of water process engineering 2019-10, Vol.31, p.100865, Article 100865
• Main Authors: Betancor-Abreu, A., Mena, V.F., González, S., Delgado, S., Souto, R.M., Santana, J.J.
• Format: Article
• Language: English
• Subjects: Electrocoagulation technique; Fluoride mitigation; Kinetics of the electrocoagulation reaction; Reactor design; Underground water remediation
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2019.100865

[Display omitted] •Electrocoagulation process for fluoride removal was evaluated.•Progressive scale-up procedure involving three pilot reactors was employed.•An optimized electrochemical reactor in a unique design was used.•The final fluoride concentration of 1.4 mg/L was attained within 10 min.•Kinetics of remediation process fitted by the Variable Order Kinetic model. Fluoride remediation in underground waters of volcanic origin was performed at laboratory scale using an electrocoagulation (EC) technique. The natural waters from certain volcanic springs on the island of Tenerife (Canary Islands, Spain) contain average fluoride concentrations in excess of 7 mg/L. Thus, it is necessary to treat the water for fluoride mitigation below the maximum acceptable concentration of 1.5 mg/L according to Spanish regulations for drinking water. The design and optimization of a sustainable process was accomplished using a progressive scale-up procedure involving three pilot reactors with different configurations and effective working volumes. A bipolar electrode cell design using aluminum electrodes was used in all cases. The good performance of the process was confirmed by reducing the fluoride concentration from 7.35 to 1.4 mg/L. The following optimized operating conditions were determined for a continuous flow cell system: current density, 10 mA/cm2; residence time, 10 min; and, half-period of polarity reversal, 1 min. Furthermore, the kinetics of the remediation process can be fitted using the Variable Order Kinetic (VOK) model, with a power relationship between fluoride concentration and residence time in the EC reactor.