NOVELTY - An electrolytic cell has electrode pair(s) defining an electrolyzer zone and having an anode and a cathode that are arranged parallelly without a separator in between. The anode and the cathode enable treatment of microorganisms in a water stream. The cell further includes an imposing mechanism for imposing a voltage across the anode and the cathode, and a supply mechanism for supplying a direct current to the cell.    USE - The electrolytic cell is used for treating microorganisms. It is used for treating contaminated water containing microorganisms, by feeding a contaminated water stream at a volumetric flow of 1-1000 m3/hour through the electrolyzer zone; electrolyzing the water stream in the electrolyzer zone defined by the electrode pair enabling treatment of microorganisms; guiding the water stream perpendicularly through the anode and the cathode while imposing a voltage across the anode and the cathode; and supplying a direct current to the anode and the cathode, thus withdrawing from the electrolyzer zone a treated water stream (claimed). It can also be useful in reducing chemical oxygen demand (COD) in contaminated waters. It can preferably be used to treat contaminated water in swimming pools.    ADVANTAGE - The inventive cell is effective in treating contaminated water containing microorganisms.    DETAILED DESCRIPTION - An electrolytic cell comprises electrode pair(s) defining an electrolyzer zone. The electrode pair comprises an anode (2) and a cathode (3), arranged parallelly without a separator in between, allowing for a high throughput of electrolyte across the anode and the cathode. The anode and the cathode enable treatment of microorganisms in a water stream having a conductivity of 0.0001-100 S/m passing the electrode pair. The electrolytic cell further includes an imposing mechanism for imposing a voltage across the anode and the cathode, and a supply mechanism for supplying a direct current to the cell.    DESCRIPTION OF DRAWING(S) - The figure is a view of an electrolytic cell.    Inlet (1)    Anode (2)    Cathode (3)    Outlet (4)