Abstract: An electrochemical installation for treating aqueous effluent containing a heavy metal, the installation comprising an electroplating reactor for the heavy metal, itself comprising a tank in which alternating electrodes of opposite polarity are placed, the cathodes being removable volume electrodes each constituted by a cassette in the form of two facing frames each supporting a wall that is permeable to said aqueous effluent, the permeable walls of a single cathode defining a space that is filled with an active granular material and in which a metal current-feed grid is disposed. According to the invention, the installation further comprises a regeneration electrochemical reactor for receiving the cathodes as anodes, the metal constituting the metal current-feed grids being selected from metals having an oxidation-reduction potential greater than that of the heavy metal to be electroplated and enabling the end of regeneration to be detected.