Apparatus and method for disinfecting water

A method for disinfecting water by means of at least one of the following reactions:

• a transformation reaction of sodium chlorite and hydrochloric acid into chlorine dioxide, sodium chloride and water;
• a transformation reaction of sodium chlorite in the presence of sulfuric acid to yield chlorine dioxide, sodium chloride, sodium sulfate and water;
• and a transformation reaction of sodium chlorate, sodium chloride and sulfuric acid into chlorine dioxide, chlorine, sodium sulfate and water;
• the method comprising introducing the reagents into a primary reactor immersed in water to be disinfected;
• generating disinfectant and oxidizing products from said reagents in said primary reactor;
• feeding said disinfectant and oxidizing products to a secondary reactor spaced from said primary reactor and immersed in water to be disinfected;
• feeding water to said secondary reactor via a supply duct extending to said secondary reactor through said water to be disinfected;
• and mixing said disinfectant and oxidizing products with water in said secondary reactor, the method further comprising regulating the pressure in said primary reactor and providing a constant and uniform flow of chlorine dioxide from a reaction chamber of said primary reactor to said secondary reactor, by means of an ejector.