There are two main mechanisms which allow UV radiation to deal with microorganisms effectively. The first of them involves creating pyrimidine dimers on the same DNA or RNA thread. It prevents cells from reproducing. The second mechanism involves breaking of cell walls and, as a result, destruction of the whole microorganism.
Disinfection effectiveness depends on the quantity of UV radiation which can be absorbed by microorganisms. The level of neutralization depends on various factors: time and intensity of lighting, type of microorganism and opacity of water. UV disinfection is the most efficient when in water there is no iron, humus substances and other substances likely to absorb radiation.