6. Ultraviolet treatment

6.1 General

UV rays are part of the non-visible radiation emitted by the sun, with wavelengths between 100 and 400 nm (1 nanometer or nm = 10 ^–9 meter or 1 millionth of a mm) (figure 33 ).

UV _C (wavelength 200 to 280 nm) has the strongest inactivating effect on micro-organisms (often referred to as the germicidal effect). They inactivate: bacteria, viruses, fungi, yeasts, algae... By crossing the membrane of these micro-organisms, they destroy their DNA molecules.