The principle

Water treatment by salt electrolysis

Disinfection of swimming pool water by salt electrolysis, is an application of the Faraday's discovery in 1834. Electro-sterilization is  a process by which substances in solution or in liquid state are dissociated by an electric current. This separation produces sodium hypochlorite.

principe 1

When the lightly saline water (7 to 10 times less than seawater) get through electrolysis cell, it's transformed into sodium hypochlorite :

2NaCl + 2H2O = 2NaOH + H2 + Cl2
salt + water = caustic soda + hydrogen gas + chlorine gas

principe 2

This chlorine dissolves in water and produces hypochlorous acid :

Cl2 + H20 = HOCI + HCI
chlorine gas + water = hypochlorous acid + hydrochloric acid

Hypochlorous acid is a powerful oxidizer which allows to sterilize water, to eliminate organic matter, bacteria, algae, contamination such as urine and sweat :

2HOCI = 2HCI + O2
Hypochlorous acid = hydrochloric acid + oxygen

principe 3

With an ideal pH -between 7,1 and 7,5- the concentration of hypochlorous acid in the electrolysis cell is such that all chloramines qui y circulent are immediately eliminated. Thanks to the action of UV, the disinfected water and hydrochloric acid interact with caustic soda chlorine is recombined back into salt. Hydrogen and oxyge are recombined back into water :

NaOH + HCI = NaCI + H2O
caustic soda + acid = salt + water

The cycle
can start