1 Fluoride removal from natural volcanic underground water by an electrocoagulation process: Parametric and cost evaluations V.F. Mena 1 , A. Betancor-Abreu 1 , S. González 1 , S. Delgado 2 , R.M. Souto 1,3 , J.J. Santana 4 1 Department of Chemistry, Universidad de La Laguna, P.O. Box 456, E-38200 La Laguna (Tenerife), Spain. 2 Department of Chemical Engineering and Pharmaceutical Technology, Universidad de La Laguna, P.O. Box 456, E-38200 La Laguna (Tenerife), Spain. 3 Institute of Materials and Nanotechnology, Universidad de La Laguna, P.O. Box 456, E-38200 La Laguna (Tenerife), Spain. 4 Department of Process Engineering, Universidad de Las Palmas de Gran Canaria, Campus Universitario de Tafira, E-35017 Las Palmas de Gran Canaria (Gran Canaria), Spain.