In france for exemple, public swimming pools must undergo several distinct treatment stages in order to meet standards. These stages are filtration, disinfection and de-chlorination. In addition, it is compulsory with swimming pools to provide information on the pH of the water, the rate of chloramines which are the residues of chlorine in contact with organic waste, the frequency of water renewal and the maximum instantaneous attendance.
Essential : water treatment with chlorine
As chemical treatment with chlorine is compulsory to make the water disinfected (and disinfecting), swimming pools that treat water with chlorine must comply with a certain number of standards. In the case of stabilised chlorine, the quantity of chlorine per litre of water must be higher than 2 mg/litre and never exceed 3 to 4 mg/litre. For non-stabilised chlorine, this quantity must be between 0.4 and 1.4 mg per litre of water.
Unfortunately, the use of chlorine generates collateral damage in the form of chlorine residues and by-products that can affect human health, called chloramines. These compounds, resulting from the degradation of chlorine and organic matter brought in by users, should not be concentrated at more than 0.6 mg/litre of chlorinated water.
Water treatment with ozone
Ozone pool treatment also has its own application standard, which defines the installation, operating and safety requirements for ozonation pool water treatment systems.
Ozonation is a natural pool water treatment that uses ozone, a bactericidal, biocidal, germicidal and disinfectant gas. Odourless, this gas does not offer an alternative to chlorine, as chlorine is mandatory, but at least a way to reduce its use.
The final step in the disinfection of public swimming pools is de-chlorination and the elimination of chloramines, and specific equipment exists for this purpose, such as UV-Cs treatment systems.
Dechlorination by UV-Cs
UV-Cs radiation allows an efficient destruction of chloramines, while maintaining an optimal water quality. Two types of technology can be distinguished here: low and medium pressure. The lamps have a power of between 120 and 300 W for low pressure and up to 3 kW for medium pressure: it is necessary to be able to regulate their power. This technology allows the establishments that use them to generate significant savings with less need for disinfection, which gives them a very good return on investment.