Ultraviolet Germicidal Irradiation (UVGI) is an extremely effective method of destroying micro-organisms. A wavelength of 254nm attacks the DNA of these micro-organisms, thereby preventing the bacteria from reproducing.
Ultraviolet (UV) disinfection is a purely physical and chemical free process. It does not change the taste or colour of the water. It has been used for nearly 100 years for producing clean potable water. However as the radiation can only work at point of contact it is still necessary to have residual chemical dosing, especially in municipal water supplies. Potable water is generally sterilised in closed reactor systems. Water is pumped into the steriliser passing along the length of the shell. Various factors determine the amount of water flow a reactor can accommodate – these include water quality, contact time and lamp power. Tertiary Sewage is generally sterilised in open channel systems rather than closed reactors. Some treatment plants can have as many as 4,000 lamps, with total power exceeding one mega watt of energy.
The primary purpose of ultraviolet (UV) radiation for Pond Sterilisation is to reduce the build up of blue green algae.
The sterilisers can be relatively small as the pond water can be continually re-circulated. Generally the power of the ultraviolet (UV) lamps does not need to be more than 55 watts, but this does depend on the size of the pond or aquarium. As with all ultraviolet (UV) sterilisers it is important to change the lamp annually and to check the condition of the quartz jacket. This is something that is quite often forgotten.
Many sterilisers use PL-S germicidal lamps.
They are cheap and reliable.