ULTRAVIOLET DISINFECTION of DRINKING/POTABLE WATER

Water supply companies world-wide are increasingly using UV technology as an effective and safe method of disinfection

The power of sunlight to destroy microbial life has long been known and appreciated (Downs and Blunt, 1877). Sunlight is an important factor in the self-purification of water in streams and in impounding reservoirs

Ultraviolet energy at wavelengths 200 - 315 nanometres (nm) penetrate cell membranes to disrupt DNA molecules preventing cell replication. Maximum effectiveness is found between 240 and 280 nm. and peaks between 260-265nm.

The UV lamps utilised in our units generate high intensity energy within this germicidal region, which makes them particularly suitable for disinfecting potable and domestic drinking water.

EFFECTIVE AGAINST ALL MICRO ORGANISMS
Some micro-organisms are resistant to chlorine, but all are susceptible to ultra violet light. Therefore disinfection by UV is very effective against bacteria, algae, moulds and yeasts. Bacteria and viruses are the major cause of water borne pathogenic diseases.  Enteric viruses, hepatitis viruses and legionella pneumophilia are known to survive for considerable periods in the presence of chlorine, but are effectively eliminated with UV treatment.

A NEW TREATMENT AGANST CRYPTOSPORIDIUM?
Recent research has suggested that certain protozoa, and particularly cryptosporidium, can be inactivated by UV light at normal dose levels. Chlorine is known to be ineffective, and ozone requires high dose levels.
The research was based on infectivity tests on rodents, and if confirmed as effective in the case of humans will provide water supply companies world-wide with a powerful and cost-effective tool in combating the problems caused by this group of contaminants.

DISINFECTION BYPRODUCTS
Chlorine in contact with organic contamination found in some waters forms halogenated by-products such as trihalomethanes (THMs) which have been proven to be carcinogenic.
Ozone possesses properties which require considerable care in its choice and application
Conversely UV energy has no adverse effect on water quality.
Studies have been carried out to determine if unpleasant by products from UV disinfection are formed. UV treated water has been examined for compounds which could affect the biological loading in distribution networks.
No negative effects have been observed. 

TYPICAL UV DOSES FOR INACTIVATION OF MICRO ORGANISMS

The table below shows the approximate dose values for the inhibition of 90% and 99.9% of waterborne organisms pathogenic to humans.

BACTERIA

VIRUSES

As well as being effective against all known micro-organisms, atg-willand systems operate at low cost and are designed specifically for ease of installation and maintenance. This is shown below compared with the most common alternative primary disinfectant, which is simple chlorination.

OUR MANUFACTURER’S CREDENTIALS

With over two decades of experience in UV Technology, they are innovators who have supplied many thousand units to the industrial market.  Their Technology products and procedures are certified to the highest standards, and designed for performance and reliability.