LUMINOR Q&A - Ultraviolet
A. No, disinfection by UV is a physical process and not a chemical process. UV does not alter the water chemistry and will not affect the taste or odour of your water. UV only addresses the microbiological concerns.A. When compared to other disinfection systems, the answer is no. As long as proper pre-treatment is maintained, an annual system check-up and lamp replacement is all that is required. As most UV systems are designed to be left on at all times, a typical household system will draw about the same energy requirements as a 40 watt light bulb!A. Although the term "UV" is most commonly associated with the potentially harmful exposure to the sun, UV has been in use for water treatment for over 100 years. UV was first used by the French in 1906 and has become commonplace in the residential, commercial and municipal markets over the past 20 years. Today, UV is likely the first form of treatment that one will look at when looking to address microbiological concerns in your drinking water.A. Sounds conflicting, but there is truth to this statement. Exposure to excessive amounts of sunlight can be harmful to your health. UV energy is actually broken up into three distinct wavelengths; UV-A, UV-B, and UV-C. Sunlight is comprised of all three UV rays, however the most powerful UV-C rays are blocked out by the earth's ozone layer thereby protecting us on earth. Direct exposure to the sun should be carefully monitored in order to minimize the exposure risk. It is the UV-C portion that is used for the disinfection of drinking water and to a microorganism such as E-coli, UV-C is deadly. It is true that you don't want to expose your eyes or skin directly to the UV light in a treatment system, however the system is designed to prevent this from happening. In a properly designed UV system, there is absolutely no risk to the homeowner.A. The UV process is a physical process as opposed to the addition of chlorine to the water to address microbiological issues which is a chemical process. This is important as UV addresses the microbiological issue without adding anything to the water or creating what is known as disinfection by-products (like trihalomethanes, which are proven to be carcinogenic). In simple terms, when a microbe is directly exposed to the UV light, the DNA (its fundamental building block) of the cell is damaged thus preventing replication. If a cell cannot reproduce, then the cell cannot cause infection.A. UV does have an effect on all microorganisms to some effect. Whether it is bacteria, virus, algae, protozoan cysts, spores, mould, etc., exposure to UV light will harm the organism. Each individual organism requires a different level of exposure (know as UV Dose) in order to prevent cell replication. Some organisms, usually viruses, require extremely high doses of UV light in order to achieve disinfection. The important issue here is that one should ensure that the UV system they are purchasing delivers enough UV dose at the end of the lamp life to ensure adequate disinfection against a typical array of organisms found in drinking water.A. Escherichia coli, or E.coli for short is a bacterium found in the lower intestine of warm blooded organisms. There are many strains of E.coli, some of which can be found in the water supply. Although E.coli has been blamed for many deaths (i.e. Walkerton in 2000), when exposed to ultraviolet light, at relatively a relatively low dose, UV is easily destroyed. Even the particularly virulent O157:H7 strain of E.coli has a 4-log (99.99%) reduction at a UV dose of 6 mJ/cm². It should be mentioned that all LUMINOR UV systems deliver a UV dose in excess of 30 mJ/cm² at the end of the lamp life.Q. My area has had problems with Cryptosporium and Giarda lamblia, I have read that UV is not effective against these organisms......is this true?A. No, although you may have read scientific articles from prominent researchers and from other UV companies, this information was based on old research studies. Original studies performed in the 1980's were based on excystation methods which lead to the belief that UV was ineffective against these protozoan cysts. In the early 2000's, it was proven by a host of independent research that UV was in fact extremely effective against both Cryptosporium and Giarda lamblia at a UV dose of less than of 10 mJ/cm². The change was a result of testing methodology used in the earlier testing. This new information has opened the doors for UV to become a mainstream disinfection method.A. The term log kill or more aptly log reduction, refers to the level of reduction that the ultraviolet energy has on a specific organisms in an logarithmic ratio. The term "Sanitation" is commonly referred to as a 2-log reduction which translates into a 50-99% reduction or a reduction of 1 out of 100. The term "Disinfection" is commonly referred to as a 4-log reduction which translates into a 99.99% reduction or a reduction of 1 out of 10,000. The term "Sterilization" is sometimes incorrectly associated with UV technology and represents a 6-log reduction which translates into a 99.9999% reduction or a reduction of 1 out of 1,000,000.A. UV dose is the product of UV intensity (total UV energy per unit volume) and residence time (total time the water is in contact with the UV light), expressed by the equation D = I x T. Typically UV dose is expressed in the units mJ/cm² but can also be in microWsec/cm². The conversion between the two is, 1 mJ/cm² equals 1,000 microWsec/cm².A. The right UV dose can be a difficult question and is directly dependant on the application. Many industrial applications are pathogen specific, meaning equipment and UV dose is chosen based on the dose requirements of a specific pathogen or group of pathogens. For the average home owner, the target pathogens typically require low UV dosages to be eradicated. As an example, E.coli, requires a UV dose of 6 mJ/cm² for a 4-log or 99.99% kill. Currently, three different UV dose levels exist in the market; 16, 30 and 40 mJ/cm². The 16 mJ/cm² dose is based on a US Public Health document produced in the 1960's. Typical waterborne pathogens will be eradicated at this UV dose, but with the emergence of some new viral contaminants and with the lack of a safety margin, this dose is typically used in instances to treat non-pathogenic or nuisance bacteria. Typical industry standards have long suggested a UV dose of 30 mJ/cm² at the end of lamp life. This dose allows for nearly double the original US Public Health dose and allows for a comfortable safety margin. The most recent UV dose suggested is that of NSF International (NSF) and the US EPA drinking water regulations, who suggest a UV dose of 40 mJ/cm². This dose is the direct result of the introduction of certain emerging pathogens (specifically rotavirus) that was found to require a dose of 36 mJ/cm² for eradication. LUMINOR publishes system flow rates at all three dose levels in their literature and allows the customer to make their own educated decision on what is best for their requirements.Q. I draw my water from the lake and have received a clean "bill-of-health" for the water from my local Health Board. Why do I need to disinfect my water?A. Even though you may have received a "negative" test result for bacteriological contaminants, it is important to realize that this is a single test and a single point-in-time. If you are drawing water from a non-municipal source, or a source that is of unknown quality, it is imperative that you follow some form of disinfection prior to the consumption of any water from that source. The reason is that there can be season fluctuations in the quality of the water and one single test, does not guarantee a safe result for 365 days of the year. If you live near a local beach that happens to be closed periodically throughout the summer months you will easily understand the reasoning. Bottom line is that if the source is unprotected, you are the only one who can ensure the safety of that source and it is your responsibility to do so.A. Yes, although you have taken the right step to install a UV system to protect you and your family from bacteriological contaminants, it is important to continue to test your water to ensure everything is working as intended. Having your water tested every six months is simply an additional peace of mind that takes very little time.A. The answer to this question depends on ones level of confidence. Although most municipalities do provide bacteriological safe water to their clients, and this is closely monitored by most provincial, state, or other regulators, there have been numerous instances around the globe where water has been provided from the municipality that may not be safe. In these cases, the municipality will inform their clients that the water is in fact unsafe for consumption and will suggest alternate means. In these cases, the UV system installed in your home acts as "insurance for your water supply". The need for this level of insurance is up to you, but considering the fact that water is the number one key to life, it seems to be a very inexpensive way to offer the security that you may be looking for for you and your family.A. A Boil Water Advisory (BWA) will be issued by your municipal water provider if the municipal water being provided to your home or business is deemed to be unfit for human consumption. This may be the result of a number of circumstances, however the municipality is informing their customers that at this point-in-time, the water is not safe for drinking, unless treated by some other method such as physically boiling the water for a minimum of 1 minute at a rapid boil. Depending on the exact nature of the BWA, other precautions may need to be taking such as avoiding baths or showers (especially in water ingestion is possible). The municipality will advise when the BWA is over and how to ensure your home's water supply is made safe. For an example of some of the procedures surrounding a BWA, please click here.A. If your local state or provincial regulations allow, the installation of a residential UV system can easily be done by the competent handyman. The typical installation involves cutting into the cold water supply and installing the UV with unions and appropriate fittings. Once installed, the unit is plugged into a separate GFCI plug. Please refer to one of the installation manuals found within this site for more detailed installation instructions.A. In deciding whether a point-of-use (POU) or point-of-entry (POE) unit should be installed one should determine the potential locations (taps) within the home where one could consume water. If there is only one tap in a small cottage or apartment, then one might consider a smaller POU system to treat a single location. The same would be true if you were looking to add either pre or post treatment to a residential RO system. Typically if there is more than one tap (a kitchen and bathroom) in a home, a POE system would be installed in a main cold water location before any cold water lines split to send water to different locations in the home. The slight increase in price for a larger system and the POE installation ensures that all locations within the home are treated.Q. I don't drink the water in my bathroom, why should I install a POE system that also treats the bathroom?A. You may decide not to drink form the bathroom tap, but what if you have guests, or someone who visits your home and assumes the bathroom water is okay for consumption. Where do you brush your teeth? If it is in the bathroom, then treating potential contaminated water in the bathroom is imperative. You don't have to swallow the water to become infected with a potentially harmful organism. Consider the brushing action against sore or bleeding gums and one can easily see the consequences. It is because of this that it is highly recommended to install a whole home POE system whenever possible.A. Yes, UV works extremely well at addressing the microbiological issues, but can be greatly impeded by the presence of other water chemistry issues. The main concerns for UV are that of water hardness, tannins, turbidity, iron, manganese and UV transmittance. As hard water can physically stain the quartz sleeve component of a UV, it is recommended that the water hardness be less than 7 gpg. Tannins should be less than 0.1 ppm or 0.1 mg/l. Turbidity should be less than 1 NTU. Iron should be less than 0.3 ppm (0.3 mg/l) and manganese should be less than 0.05 ppm (0.05 mg/l). Although UV can be used on waters with a UV transmittance of less than 75%, for residential applications at the systems rated flow, it is recommended that UVT levels be greater than 75%. All these issued can be addressed by other water treatment equipment such as filters and water softeners (many of which can be found on this site). The minimum pre-treatment that is recommended is the installation of a 5 micron prefilter in front of the UV system. Again, these systems can be found in the filtration section of this site.Q. Tannins are mentioned in the pre-treatment process. What are tannins and why do I need to remove them from my water prior to the UV?A. Tannins, also known as tannic acid or humic acid is a nuisance contaminant that affects the functionality of a UV system. Tannin in drinking water usually comes from composting organic matter (i.e. leaves, vegetable matter, etc.) and is most likely to appear in springs and wells bordering swampy areas or near coniferous tress. Tannins colour the water with a yellow hue and can cause staining on fixtures and affect the aesthetic quality of drinks. In relation to UV tannins interfere with the UV's ability to penetrate into the water due to the tannins absorption capabilities. For a UV system to function properly, tannins must be removed from the water via a special macroporous Type 1 anion exchange resin, or by chlorination.A. UV transmittance or simply UVT describes the measurement of a fluids ability to transmit UV light. Typically, municipal water supplies have UVT levels of greater than 95%, whereas deep water wells typically have UVT levels around 85%. The UVT of surface waters can vary greatly depending on the source and surrounding geography. UVT can be easily tested with a spectrophotometer which most laboratories or UV manufacturers have. Waters with lower UVT's will require more UV energy to deliver a similar UV dose than waters with a higher UVT. LUMINOR systems are tested at a 95% UVT level and their rated flow is based on the waters having a minimum UVT level of 95%. If your water has a lower UVT, the system will deliver a lower UVT dose, or the flow rate through the system will need to be decreased to achieve the same UV dose. Dosage curves are available for all LUMINOR systems to aid in this selection. As a precaution, it is recommended that all water treated by a UV system have a minimum UVT level of 75%.Q. I understand the need for pre-treatment, but how can I tell if I have any of the problems that potentially require pre-treatment?A. Before the installation of a UV system, your water should be tested to determine the basic water chemistry. The minimum tests should include hardness, tannins, turbidity, iron, manganese and UV transmittance. These tests can be typically performed by a LUMINOR distributor or by the many testing laboratories that are in existence.Q. I've made the decision to install a whole home POE UV system, but where exactly do I install the system?A. The UV system should be the last piece of treatment equipment. Water softeners, filters, etc. should all be installed prior to the UV system. All the treatment equipment should be installed on the main cold water line feeding the house and before any branch lines including those feeding the hot water heater.Q. I've been told that UV does not have any residual disinfection like chlorine, so how do I get rid of the bacteria that may reside in my plumbing system?A. Before the water is consumed after the installation of a UV system, the entire distribution system (piping) must be disinfected with chlorine to ensure that the UV system delivers its disinfected water through a disinfected distribution system. This can be easily done by adding household bleach, or similar disinfectant, in the prefilter housing (that must be installed with each UV system). First, remove he cartridge and then fill the filter sump with the bleach. Then go to each tap in the house and run water until you sell the bleach and then turn off the tap. Make sure you flush the toilets, run water into the dishwasher and washing machine as well as any showers. Finally run water through any outside hose bibs and any other location that has water. Leave the entire system for a minimum of 30 minutes and then flush the system to remove the bleach. Once this is complete, the water will be ready for consumption. Throughout this process, do not shut off the UV system (please note that if you have a UV system that contains a UV monitor, the alarm may sound during this process as the bleach interferes with the proper reading of the UV monitoring system).Q. I have a vacation property and I only use it occasionally......can I turn off the system to save energy?A. You can turn the system off if you are away for extended periods of time, however you must remember that if you turn the system off, you will need to disinfect the distribution system each time you restart the UV system as there is a possibility that the bacteria that may exist in the water can migrate and replicate through the UV system when the system is off and could contaminate the distribution system after the UV system. As UV has no residual, there will be no way to clean up the down bound distribution system besides disinfecting the entire system with bleach. Considering this and the fact that a typical household UV system consumes about as much power as a 40 watt light bulb, many people elect to leave the UV system on, even when they are away for an extended period of time.Q. I have a vacation property that I don't use in the winter.....do I have to worry about the UV freezing?A. Yes, as the UV is part of your regular water system, you will need to properly drain the water from the UV reactor the same as you would with any other fixture in your vacation property.Q. I've read that some UV systems turn the lamp on and off every time water is drawn......should the LUMINOR system be turned on and off?A. There are some countertop POU systems that are specifically designed to be turned on and off every time water is drawn from the faucet. These systems are specifically engineering for this function. LUMINOR's POU and POE systems should not be turned off unless it is for an extended period of time. The systems are designed for continuous disinfection and not for on-off cycling as this can severely reduce the overall life of the UV lamp.A. The UV lamp acts as the heart of the UV system and LUMINOR uses the best available lamp technology. All our lamps are manufactured with a proprietary internal coating providing consistent UV output over the entire life of the lamp. Ceramic lamp bases are used for thermal efficiency and structural integrity. The lamps bases are colour coded and base marked for easy identification and maximum output.A. UV lamps do age and do so in the same manner as a standard fluorescent lamp. LUMINOR's low pressure (LP) and low pressure, high-output (LP-HO) lamps have a rated service life of 9,000 hours or approximately one year of continuous use. LUMINOR's amalgam lamps used in our commercial/industrial and municipal lines have a rated service life of 12,000 hours. At LUMINOR, we guarantee all our lamps to have a minimum life of 1 year. It should be noted that illumination does not necessarily mean disinfection. The bluish glow given off by a low pressure mercury vapour lamp is actually the glow of the mercury vapour. The actual UV energy providing the disinfection is invisible to the naked eye. A lamp that is still emitting the bluish light does not mean it is providing enough, or any, UV energy. This is why the lamps should be changed at the time as recommended by the manufacturer. On some LUMINOR models there is an integral lamp change reminder built into the system to warn the user when it is time to change the UV lamp.A. Yes, the installation of a bypass valve is highly recommended in order to allow water flow in case the UV system has to be removed for some reason. Please note that notification should be provided, and posted, at each location where water is drawn to ensure that no one accidently consumes contaminated water. When the system is put back online, a full chemical disinfection must be made on the distribution system.A. No, all LUMINOR systems are engineered to achieve a minimal pressure drop for the specific flow rates of each individual model. Typically pressure drops are less than 3 psi.A. Depending on the influent water quality, the quartz sleeves may need to be removed and physically cleaned. On most LUMINOR systems, there is no need to drain the reactors as is the need in competitive systems. The sleeve is easily removed by remove the top retaining nut and carefully sliding out the quartz sleeve. A commercially available scale cleaner such as Lime-Away or CLR can be used to clean the sleeve. When cleaning the sleeve wear gloves to ensure that no fingerprints are left on the sleeve and ensure that the sleeves are thoroughly rinsed with clean water to remove any of the cleaning agents before reassembling.A. All LUMINOR systems come with a lamp monitoring system. If the lamp is not illuminated and audible alarm will sound. Please note that this alarm deals with a "lamp-on" condition only. Lamps that are not changed out on an annual basis, or systems that do not follow the pre-treatment protocols may result in a false sense of security. The only way to ensure the system is working properly is to obtain a bacteriological test.A. As the UV lamps are removed through the axial length of the reactor, a space equal to twice the length of the reactor is needed. In the case of a typical 38 lpm (10 gpm) reactor, this would account for a space requirement of approximately 165 cm (65").A. As the UV unit is a self contained pressurized vessel, the orientation of the reactor chamber is not a concern from a disinfection standpoint, however for ease of installation and service, it is recommended to install the system in a vertical orientation with the retaining lamp (and lamp removal) located at the top.Q. If the units are rated at a certain flow rate, how do I make sure I don't exceed that rated flow?A. To be absolutely sure that the UV system does not exceed the manufacturers rated flow, the installation of a flow restrictor is recommended. These flow restrictors are designed with a variable orifice that fluctuates with variations in water pressure. The maximum flow is controlled by the restrictor which is ideally installed on the outlet port of the UV reactor. Flow restrictors can be purchased through your looking plumbing supply distributor.A. No, these systems are designed to be installed indoors and away from the elements. The manufacturer's warranty will not apply if the units are installed in an outside environment, or if they are exposed to spraying or splashing water.A. This does depend on where you live and on what type of application the unit is being installed on. You should check with your local government and should follow their recommendation. It is important to remember that NSF International is a voluntary tested organization and is just one of the many testing organizations that exist.A. To obtain replacement components for your UV system, you should contact the local retailer where you originally purchased the UV system. They will be able to supply you with the part, or order one for you. If that option is unavailable to you, replacement parts can be obtained directly from the factory. Please click here for further information.A. The UV system is installed on the cold water line in your home. The disinfection occurs by the ultraviolet lamp contained inside the stainless steel reactor chamber. Although the UV energy itself gives off no heat, the low pressure mercury vapour lamp ("light bulb") does emit energy in the form of heat. It is this energy that can in some cases warm the water up. This may be a problem when there is a long period of dormant (no flow) activities such as at night. The problem may be compounded if the UV system is located close to a tap. To remedy this situation, and recommend by most municipalities, run the water for a few seconds before filling a glass. This will not only rinse the lines with any stagnant water, but will also flush the warm water from the system. Most people view this feature as an additional way to know that your system is still on an operating as in most cases the UV is installed somewhere out of the way and away from normal view,A. The UV lamp should be disposed in accordance with your local regulations. The lamps should be disposed in the same fashion as any other fluorescent light fixture that may be in your home or office. At LUMINOR, we strongly encourage recycling...for more information, please visit www.recycle.org.