Abstract: The invention concerns a method consisting: in passing the sea water through an electrically conductive catalyst (10), arranged in the cathode section of an electrolytic cell (1), comprising a cathode section (3) and an anode section (4) provided with, the former, with at least one cathode (11a, . . . ) and, the latter, with at least one anode (18) and separated by a wall (2) permeable only to the cations and in circulating, in the anode section (4), a conductive aqueous solution of a particular anolyte; in providing an electric voltage between the cathode and the anode of the cell (1) while maintaining the contents of the cathode and the anode sections at specific potentials, so as to produce, in the cathode section, consumption of oxygen dissolved in the treated water and in decomposing, in the anode section, an appropriate amount of solution for ensuring the electroneutrality of the treated water.