Using ultraviolet (UV) disinfection on drinking water systems

Ultraviolet disinfection is a well-established method for adequate disinfection of drinking water supplies. UV disinfection is intended to inactivate human pathogens, such as viruses and bacteria, potentially present in raw water before proper disinfection. As water passes through the UV unit, an ultraviolet range of light inactivates these human pathogens.

To effectively kill microorganisms, ultraviolet has to transfer light through the quartz sleeve into the water stream. However, if particles or contaminants in the water or other contaminants like iron or manganese coat the quartz sleeve, the UV light may not be effectively transferred into the water supply, and some bacteria will survive.

Disinfection is the method of destroying or preventing the growth of diseases carried by microorganisms. But what does this mean? There are two significant types of disinfection: chemical and physical. Chemical disinfection requires adding a substance to the water (or other material) to kill or inactivate microorganisms.

Chlorine, for example, is a very commonly used disinfectant for water treatment. On the other hand, physical disinfection treats the substance being disinfected but does not add anything to it. Boiling water, for example, will kill many dangerous bacteria and leave the water safe to drink.

Chemical disinfectants have been used successfully for many years but carry several risks. Chlorine, for example, is used by many water treatment plants because it’s relatively inexpensive and very effective.

However, chlorine and chloramines (a related chemical disinfectant) often react with other compounds in the water, which are chemicals compound. Many people also find that chlorine-treated water has a particular smell and taste that they find objectionable.

Physical disinfectants are often preferred over chemical means because they don’t add anything to the water that could produce dangerous by-products.

There are challenges with physical methods, however – after all, you wouldn’t want always to have to boil all of the water in your home before you use it! UV water treatment has come a long way in recent years, and most people find that it’s far superior to chemical means for treating water in their homes or businesses.

Note that these systems are sometimes called “UV water sterilizer systems, ” but this is misleading; it’s nearly impossible to prove complete sterilization. However, well-designed UV systems can kill or inactivate 99.99% of dangerous microorganisms.

UV water purifier works simply by exposing your water to specific wavelengths of ultraviolet light. This light damages the nucleic acids and DNA of the cells. UV light doesn’t necessarily kill microorganisms but is very effective at inactivating them and preventing them from reproducing colonies.

Remember that microorganisms only replicate and make colonies, so we get sick if we consume them in large amounts through our drinking water. These organisms can enter our system and pass right through without causing illness.

DNA is the genetic coding found in all living things. Within each DNA strand, there are different sequence codes, with each sequence coding for other characteristics.

UV light can be damaging to DNA – in fact, the reason that it’s a good idea to wear sunscreen when you’re outside is that the UV light in the sun’s rays can damage the DNA in your skin cells, causing them to reproduce incorrectly and leading to skin cancer.

Because microorganisms are straightforward creatures, their DNA is primarily coded for replication. The light from a UV water purifier is absorbed readily in one spot in the DNA strand causing it to break the bond.

Products for Ultraviolet Disinfection water treatment process

Advantages:

• Physical disinfection adds no potentially harmful chemicals
• Virtually instantaneous disinfection, requiring no holding tanks like chlorination does
• No change in taste, odour, pH or conductivity of treated water
• No handling of toxic substances, including special storage requirements
• No disinfection by-products (e.g. THMs)
• Deficient power consumption
• No removal of beneficial minerals
• Meagre setup cost and low operational expense when compared to other technologies
• Environmentally friendly
• The universally accepted treatment process for potable and non-potable supplies
• Automatic, unattended operation

Disadvantages

• Water must be pretreated for a UV water filter to work effectively
• Power is required; during a power outage, the system will not work
• UV lamps should be changed yearly
• No residual protection – once the water leaves the UV water purifier, it could become reinfected
• UV water treatment works best with high-quality water with little or no sediment.
• Easy maintenance, with no moving parts to wear out
• Safe to use
• More effective against cysts than chlorine