Method for electrolytic water disinfection without cathodic hydrogen evolution

Abstract

The invention relates to a novel device for electrolytic disinfection of drinking water, service water and waste water using anodically generated disinfectants. The cathodic formation of hydrogen is prevented by using gas diffusion electrodes as the cathode. Atmospheric oxygen is reduced to hydroxyl ions and/or hydrogen peroxide at the gas diffusion electrodes. A permanent anode can be positioned between two gas diffusion electrodes. The latter then function alternately as a cathode or a second anode. This polarity change enables the removal of the deposits containing metal ions that form during the cathodic reaction from the gas diffusion electrodes. The substances with the disinfecting effect are produced through the use of different electrode materials for the anode and the diffusion electrode either at both anodes or at the anode and cathode.

1 .- 13 . (canceled)  
     
     
         14 . A method of electrolytically disinfecting drinking water comprising the steps of: 
 contacting an anode and a cathode with water to be disinfected, the cathode comprising a gas-diffusion electrode including a catalyst preventing the formation of hydrogen peroxide in said water,    contacting the cathode with a supply of an oxygen-containing gas, and    supplying the anode and cathode with a flow of electrical current sufficient to generate disinfectant substances in the water at the anode in sufficient quantity to make the water safe for drinking.    
     
     
         15 . The method of  claim 17  wherein the electrical current is supplied at a level sufficient to develop a current density of between 18 and 36 mA/cm 2 .  
     
     
         16 . The method of  claim 17  wherein the electrical current is supplied at a level sufficient to develop a free chlorine content of at least 33 mg/Ah.  
     
     
         17 . The method of  claim 17  further comprising the steps of positioning a second cathode in the water to be disinfected, and periodically connecting the electrical current to one of the cathodes in such a manner as to operate the cathode as an auxiliary anode.  
     
     
         18 . A method of electrolytically disinfecting drinking water comprising the steps of: 
 contacting an anode and at least one cathode with water to be disinfected, the at least one cathode comprising a gas-diffusion electrode,    contacting the at least one cathode with a supply of an oxygen-containing gas,    supplying the anode and at least one cathode with a flow of electrical current sufficient to generate disinfectant substances in the water at the anode in sufficient quantity to make the water safe for drinking, and    forming the at least one cathode with sufficient catalyst to prevent the formation at the cathode of hydrogen peroxide in the drinking water.