water treatment by means of oxigen

[chem geek]

Even after translation, I too could not find anything about diamond electrodes and oxygen generation on the site you linked. However, there is such a thing as boron-doped diamond electrodes (see this list of papers on the topic) that through electrolysis mostly produce oxygen gas, but also produce a relatively high concentration of hydroxyl radicals that are indeed very powerful oxidizers, stronger than ozone and very short-lived. The Oxineo® product from Adamant Technologies is an example, but this technology is expensive so is typically only used in water treatment and in some commercial/public pools. A similar system might also be used in the Ace® Salt Water Sanitizing System for spas though that is not as clear (they do not refer to boron-doping of their diamond electrodes). Because the system is electrolysis, one also gets other sanitizers such as chlorine or bromine depending on the salt levels of chloride and bromide, respectively. The hydroxyl radicals can combine to form hydrogen peroxide (which would react with chlorine to reduce it) and can form MPS if there are sulfates in the water and can form some ozone as well.

The most important thing to understand with these "active oxygen" systems, even when legitimate as with boron-doped diamond (BDD) electrodes or with ozonators, is that they do not leave a substantial residual of disinfectant in the water. So you still need to use a bulk-water disinfectant such as chlorine in order to kill pathogens that stay stuck to pool surfaces and never make it through the circulation system and also to kill pathogens to prevent person-to-person transmission of disease (especially in commercial/public pools where one sick person can infect dozens or hundreds of others). Since chlorine is also a decent oxidizer and since residential pools typically have low bather-load (so low oxidizer demand), there is little need for such supplemental oxidation systems. This is especially true in outdoor residential pools where sunlight breaks down chlorine to produce ... wait for it ... hydroxyl radicals (HOCl + hν --> OH• + Cl•)! Indoor pools not exposed to sunlight can often require supplemental oxidation or a UV system to control chloramines.

So while not bogus, a boron-doped diamond electrode system would be an expensive add-on with relatively small incremental value in an outdoor residential pool. In a high bather-load commercial/public pool or with some indoor residential pools and possibly residential spas, it is more useful, though still expensive. If you want automated production of chlorine, then get a saltwater chlorine generator.