bestUV is an innovative manufacturer of professional ultraviolet (UV) water treatment systems for industrial and municipal markets. UV reactors are optimized with ‘in-house’ Computational Fluid Dynamics. bestUV selects each unit for its unique application, applying in-depth knowledge of microbiology, chemistry, process and reactor design.
bestUV is an innovative manufacturer of ultraviolet (UV) water treatment systems for professional market segments like:
- industrial process water
- communal drinking water
- communal waste water
- maritime and off shore
- public swimming pools
- For high-efficiency, state-of-the-art performance, bestUV applies ‘state-of-the-art’ low-pressure (LP) and medium-pressure (MP) UV lamp technology.
- The UV reactors are optimized with ‘in-house’ Computational Fluid Dynamics (CFD).
- bestUV selects each UV system for its unique application, applying in-depth knowledge of microbiology, chemistry, process and UV reactor design.
- Special UV reactors are produced for corrosive waters and environment.
- Contact the ‘experts in ultraviolet light’ to fully optimise your new or existing water treatment system with bestUV technology.
Ultraviolet (UV) light has become widely accepted as an alternative for chlorination, ozonation, and heating of water. Use of UV light has proven to be harmless for humans, animals and environment. UV light protects against pathogens and food-spoiling micro-organisms.
The UV sensitivity of micro-organisms differs per species. Each water type has its specific properties and requirements. The use of UV equipment to protect against micro-organisms has thus to be judged and advised by specialists only.
Ultraviolet light is part of the electromagnetic spectrum, to be found between visible light (above 400nm) and X-rays (below 40nm). Depending on the application certain UV areas and/or wavelengths are important e.g.:
- disinfection: 200 – 300nm (optimum at 200 and 265nm)
- deozonation: 200 – 300nm (optimum at 250nm)
- advanced oxidation processes: 200 – 260 (optimum at 200nm)
- dechloramination: 200 – 400nm (optimum. at 245, 290, 360nm)
- dechlorination: 200 – 350nm (optimum 300nm)
- OH-radical formation from TiO2: >365nm
So, each process needs a specific approach in use of ultraviolet light to effectively treat the water.
Ultraviolet (UV) light is part of the electromagnetic spectrum between visible light and
The UV spectrum is divided in 4 ranges:UVA
This range extends from wavelengths between 315 – 400 nm (nanometer). Light in this range is absorbed by the skin and leads largely to “sun tanning”.
Application for these wavelengths:
- attraction of insects
- katalysation of titaniumdioxide (TiO2)
- breakdown of trichloramine, part of ‘chlorine smell’ in swimming pools
This range extends from wavelengths between 280 – 315 nm. Light in this range is also absorbed by the skin but leads largely to “sun burning”.
Applications for these wavelengths:
- inactivation of microorganism, as DNA absorbs wavelengths below 315 nm
- breakdown of dichloramine, part of ‘chlorine smell’ in swimming pools
- breakdown of ozone
This range extends from wavelengths between 200 – 280 nm. This range is absorbed by DNA and RNA (genetic molecules) in micro-organisms and leads to their inactivation (‘killing’) by inhibiting their ability to replicate.
Applications for these wavelengths:
- inactivation of microorganisms, as DNA/RNA absorbs at maximum wavelength of 260-270 nm
- breakdown of ozone, hypochlorite, hydrogenperoxide
- formation of hydroxylradicals
This range extends wavelengths from 100 – 200 nm. It is called “vacuum UV” since UV light in this range is strongly absorbed by water or oxygen in air and can thus only exist in vacuum.
Applications for these wavelengths:
- production of ozone, active oxygen
- dissociation of chemical bands
A medium-pressure (MP) UV lamp has some important differences compared to the more well known low-pressure (LP) UV lamps. These differences are major reasons to select UV systems with medium-pressure lamps:
- high power
- energy efficiency
- compact size
- reduce quantity needed in a UV reactor
- broad range of wavelengths (200 – 400nm)
- photobiological effects
Some applications may require the use of medium-pressure UV lamps because they emit a broader range of wavelengths. Such applications include:
- dechloramination in public swimming pools (reduction of all chloramines, mono-, di- and trichloramines, only reached by the emission of wavelengths between 200 and 400nm.
Two other important reasons to use medium-pressure UV lamp technology is:
- to reduce the footprint of the installation, as high-powered medium-pressure lamps greatly reduce the size of a UV reactor.
- to reduce the quantity of UV lamps because medium-pressure UV lamps have higher power fewer are required compared to a low-pressure UV lamp systems.
Low-pressure (LP) UV lamp
Low-pressure (LP) UV lamps have some important differences compared to medium-pressure (MP) UV lamps:
- low power
- larger size
- greater quantity needed in a UV reactor
- limited range of wavelengths (254nm) emitted
Some applications use of low-pressure UV lamps, mainly because of:
- low capacity (single UV lamp)
- frequent STOP and GO operations
Two other important reasons to use low-pressure UV lamp technology are:
- high efficiency of the lamp, up to 40% of the power converts to germicidal energy,
- specific 254 nm wavelengths, well known for disinfection purposes.
Ultraviolet disinfection systems for water are proven to provide reliable reduction of pathogens and food-spoiling microorganisms in the UV treated water if sized and operated correctly. Most important for the successful prediction and operation of a UV system is to test the system’s performance under all potential conditions.
In recent years UV sizing models, such as Computational Fluid Dynamics (CFD), have been introduced to guide system design and predict performance in the intended environment.
best UV experts base system size on conservative estimations for peak flow conditions, water quality, and design UV dose. Using CFD-modeling, the experts are able to test and predict system performance under all kinds of conditions.
bestUV also uses CFD modeling to design systems with the highest level of energy-efficiency to ensure the smallest carbon footprint. It does so without sacrificing safety or the effectiveness of the disinfection process.
bestUV uses ‘in-house’ CFD models that are controlled and optimized by practical bio-assay results.
As a result of our CFD-modeling, performance of a bestUV system is guaranteed.
Ultraviolet (UV) light is a natural part of sunlight; the short wavelengths are absorbed by the protecting ozone layer. UV lamps designed for water disinfection use a gas mixture containing the element mercury (Hg) vapour to produce ultraviolet light.
Mercury is an advantageous gas for UV disinfection applications because it emits light in the germicidal (‘germs killing’) wavelength range (UVC and UVB). The light output depends on the concentration of mercury atoms, which is directly related to the mercury vapor pressure.
Mercury at low vapour pressure produces essentially monochromatic (single wavelength) UV light at 253,7 nm, so-called low-pressure UV lamps.
At higher vapour pressures, the frequency of collisions between mercury atoms increases, producing UV light over a broad spectrum. These so-called polychromatic (more wavelengths) medium-pressure lamps have an overall higher intensity.
Exposure to UV light in the wavelength spectrum of 200 – 400 nm damages the genetic (DNA and RNA) and other molecules inside a micro-organism. The damage ‘kills’ the specific micro-organism.
Bacteria, protozoa, viruses, fungi, algae are all sensitive to UV light. Because of differences in their shape, they are sensitive to different wavelengths.
Applying UV light does not leave residuals in the water, which is an advantage over chemical disinfection methods. UV is proven to be very effective in inactivation of Giardia and Cryptosporidium with a very low dose.
The use of chlorine as a disinfectant is commonly accepted worldwide. People are becoming more concerned about the by-products of chlorine as it reacts with other organic compounds producing various compounds like e.g. trihalomethanes (THMs). THMs are documented as probable or possible human carcinogens.
Other disadvantages of chlorination are how it changes of taste and odours, the need for additional equipment such as tanks to guarantee proper contact time, and necessary monitoring to ensure proper concentration levels.
Chlorination is known to provide poor disinfection performance against viruses such as enterovirus and hepatitis A and microorganims such as Giardia and Cryptosporidium.
Ozone, one of the strongest oxidants known, is effective as an oxidising agent in reducing bacteria with a relatively short exposure time. Ozone generators are used to produce ozone gas on-site since the gas is unstable and has a very short life.
These systems must be carefully installed and monitored because high levels of ozone will oxidise and deteriorate all downstream piping and components. High levels of ozone are extremely harmful, especially in enclosed or low ventilation areas.
Furthermore ozone forms highly carcinogenic by-products at high bromide levels such as bromate, bromoform, dibromeacetic acid etc. This is becoming an even bigger concern with drinking water disinfection. As a result of by-product formation some countries have already banned ozone for drinking water treatment.
Overall, the major advantages of ultraviolet light versus chemicals:
- no residuals
- no disinfection by-products
- no effects on color, taste, odor
- no storage of chemicals
- effective against all microorganisms, including Giardia and Cryptosporidium
- compact footprint
- environment and human friendly
Comparison of two UV lamp technologies for treatment of swimming pool water
Use of ultraviolet (UV) light for treatment of chlorinated swimming pool water is becoming increasingly popular.
Medium-pressure UV lamps are favoured for reduction of chlorinated disinfection by-products (DBPs). The use of medium-pressure UV lamps is supported by theoretical and practical research work in Belgium (2003) The Netherlands (2007) and Denmark (2009).
In addition to research, thousands of medium-pressure UV systems are in use in swimming pools all over the world effectively disinfecting pool water and reducing chloramines (chlorine smell).
The most problematic health-related component of bounded chlorine is trichloramine (TCA). TCA is 250x more irritating than monochloramine and escapes abt. 1000x more easily into pool air. Thus, breaking down trichloramine is the primary goal in pool water treatment by UV.1
Health impact of trichloramine
Research work by the University of Leuven, Belgium showed a relationship between childhood asthma and indoor swimming pools. The most suspected component causing childhood asthma is trichloramine.2
Medium-pressure UV lamps
Low-pressure UV lamps emit a single wavelength (254nm) able to break down monochloramine.They are not able to break down the di- and trichloramine, the most irritant chloramine. Medium-pressure UV lamps emit wavelenghts between 200 and 400 nm, which are able to break down the three components of bounded chlorine: mono-, di-, and trichloramine.
Theoretical survey The Netherlands (2007)
In 2007 the Ministry of Health conducted research involving the protection of human health in the presence of chlorinated disinfection by-products such as trichloramine. Of 11 techniques, the most promising technology for disinfection pool water is medium-pressure UV lamps in combination with hypochlorite. It is to expect that this technique effectively disinfects pool water while producing the lowest amount of DBPs.3
The lowest levels of combined chlorine (0,2 ppm) are required and achieved in Germany. During the past 10 years, medium-pressure UV lamp systems have efficiently produced disinfected pool water with lowest levels of combined chlorine in German pools.
Practical full scale test in Denmark (2009)
In 2009 a group of European researchers tested the possibilities for improvement of pool water and air quality. Four different technologies were tested in comparable situations. Two technologies were based solely on photolysis by direct UV light, two other technologies were based on oxidation (TiO2 and ozone) by indirect UV light. Of the 4 techniques, the medium-pressure UV light showed efficient control of combined chlorine while low-pressure was less efficient.4
Medium-pressure UV lamps are favoured for reduction of chlorinated disinfection by-products (DBPs) such as combined chlorine (chloramines) in pool water and air. Low-pressure UV lamps emit only one single wavelength, which performs well for disinfection but is much less effective in photolysis of disinfection by- products.
Breaking down trichloramine is a primary goal, as it is linked to health-related problems and it is volatile and irritating. Researchers concluded that medium-pressure UV lamp systems have technological advantages over low- pressure UV lamps.
Medium-pressure UV lamp systems need less energy, use fewer UV lamps and units are compact in size with little headloss in cases of ?in-one-line?-construction. Thousands of swimming pools confirm the findings of research work and use medium-pressure lamp technology to ensure safe and pleasant swimming pool water.