UV for Disinfection Applications

Ultraviolet light is used in a wide array of applications.  One of those applications is disinfection.  Disinfection is the inactivation of pathogenic organisms to prevent the spread of diseases.  UV systems can destroy up to 99.99% of harmful micro-organisms without adding chemicals or changing the water’s taste or odor.  UV is one of the few methods of disinfection approved in the United States by the FDA.  UV is a quick, reliable, and cost-effective  method of disinfecting water.   UV technology is used in food, air, and water purification applications.

How does UV work in the disinfection process?

Microorganisms are exposed to and absorb UV light.  The UV light alters the microorganism’s genetic material (DNA) eliminating its ability to reproduce.  UV does not actually kill but rather inactivates all types of bacteria.

 


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Microbial Disinfection

• Uses the 254 nm lamp.


• The UV energy penetrates the cell wall and permanently alters the DNA structure of the microorganism.


• The microorganism is “inactive” and unable to reproduce. It eventually dies.

UV is effective for inactivating these types of microorganisms:

• Bacteria: Coliform Bacteria


• Coli


• Hepatitis Virus


• Influenza Virus


• Legionella Pneumophila - Thin, aerobic, non-spore forming bacteria requiring cysteine & iron to thrive


• Streptococcus feacalis - Spherical shaped infectious bacteria found in pink eye, bacterial pneumonia, strep throat, scarlet fever, & urinary tract infections in humans, pets, and livestock


• Typhoid Fever - Caused by Salmonella Paratyphi with 15% fatalities

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Markets that use UV for disinfection

• Food & Beverage – The food and beverage industry includes a multitude of very diverse businesses. These include bottled water, carbonated and non-carbonated beverages, crop irrigation, food packaging, meat and poultry processing, and dairy plants.  UV technology aids in the successful control of pathogenic microorganisms.  Disinfection is the most commonly used application for UV light in water treatment.  A properly sized UV system is designed to meet a minimum of 3-log reduction using a minimum of 30,000 micro-watt seconds (or 30mJ/cm²) at one year, the end-of-lamp life (EOL).  Typical locations of installation would be:  Points-of-fill, points-of-rinse, brine solutions, post-carbon filter, pre-membrane filtration or RO (reverse osmosis), post-water and pre-syrup storage tanks.  A UV system can significantly reduce the microbial counts by destroying at least 99.9% of the bacteria present in the influent stream, when installed at the appropriate locations in the treatment process loop such as downstream of the carbon bed and/or directly upstream of the membrane filtration or RO.


• Life Sciences - This industry includes Pharmaceutical and Biotechnology - UV units are reliable, deliver consistent performance and have become the disinfection method of choice for the Water-for-Injection and United States Pharmacopeia water systems.  These value added systems are found in both the pre-treatment and process areas of the water system.  A pharmaceutical water system could have several locations where UV equipment would be installed.   Some typical locations of installation would be post-carbon filter and pre-RO (reverse osmosis). When installed downstream of the carbon bed and/or directly upstream of the RO unit, a UV system can significantly reduce the microbial counts by destroying at least 99.9% of the bacteria present in the influent stream. Disinfection is also recommended for the process distribution loop and pre-storage tank.


•  Microelectronics – A microelectronics water system could have several locations where UV equipment would be installed. Some typical locations of installation would be post-carbon filter and pre-RO (reverse osmosis).  When installed downstream of the carbon bed and/or directly upstream of the RO unit, a UV system can significantly reduce the microbial counts by destroying at least 99.9% of the bacteria present in the influent stream.  Disinfection is also recommended for the process distribution loop and pre-storage tank.


• Recreational Water – Disinfection plays a key role in public and private pools, splash parks, water parks, and any swimming venue. Swimming pool water must undergo treatment in order to remain clear and clean, free from harmful substances, bacteria, viruses, algae and other pathogens, as well as, remain suitable for use by the swimmers.   For most pool operators, chlorine is the disinfectant of choice, although there is growing awareness regarding the negative health impacts of chlorine and its by-products. On the other hand, unlike bacterial pathogens, Cryptosporidium oocysts are resistant to chlorine disinfection and can survive for days in treated recreational water venues.  UV light represents a powerful technology that has been successfully deployed in swimming pools for several years. UV disinfection of pools and splash parks is a complimentary way of providing an effective method of inactivating a wide range of waterborne pathogens including Cryptosporidium.  Disinfection is the most common application of UV light in water treatment. A properly sized UV system is designed to meet a minimum of a 3-log reduction using a minimum of 30,000 micro-watt seconds (or 30mJ/cm²) at one year, the end-of-lamp life (EOL).  A typical location of installation would be after filtration.

Summary

UV is a safe and effective method for disinfection of water.  It does not add any undesirable side effects to the water such as color, odor, chemicals, or taste.  UV does not create any harmful by-products.









 

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