How disinfection works

The effect of UV light on bacteria, viruses, spores and moulds has been known to science for many years. Ultraviolet energy at 254nm wavelength is radiated by special lamps. The shortwave ultraviolet energy is lethal to micro-organisms. The ultraviolet rays penetrate the cell membranes and destroy the DNA inside the cell, effectively destroying the organism and it’s ability to reproduce. Ultraviolet disinfection is extremely fast, it requires no chemicals or additives and cannot be overdosed. No chemical residuals are left in the treated water.

Inside the stainless steel chamber runs a sleeve made of a special quartz glass transparent to UV rays and a UV lamp inside this. The sleeve is sealed into the chamber at each end creating a water jacket around the lamp. Water to be treated enters the chamber at one end and exits at the opposite end. As the water passes through the chamber it is exposed to the ultraviolet rays and micro-organisms are killed.

In private water supplies the UV system is the last part of the treatment system after the pump, filtration system and storage. A sediment filter is normally fitted just before the UV. This sediment filter stops particles getting through to the UV behind which bacteria can hide and thus not be killed. For domestic systems a 10 inch filter housing with a 5um or 10um filter is normally adequate. For dirtier waters or those requiring a higher flow rate larger sediment filters or two in series may be needed.