How UV technology works


UV technology is both the oldest and one of the very latest technologies used to disinfect fluids. The method is based on the natural disinfection action of the sun’s rays. UV lamps imitate the disinfecting rays of the sun. ULTRAAQUA UV systems produce the same ultraviolet germicidal rays, just thousands of times stronger. No bacteria, viruses, molds, or spores can withstand this treatment.

The reaction time between the UV irradiation and the organism to be inactivated is very short and does not create any by-products at all. The water quality, both physical and chemical, remains identical before and after treatment using the UV technique. The UV disinfection can therefore take place at any conceivable and necessary place in a system.

The radiation dose or fluence is a design parameter for the disinfection effect of the UV irradiation. The necessary dose to achieve a given inactivation depends on the organism to be killed. The measurement is expressed in mWs/cm² and/or mJ/cm².

UV Transmission is a measure of the ability of the UV light to pass through 1 cm of liquid. When light irradiates the water, the water absorbs part of the radiation, and the light intensity decrease with distance from the lamp. The design of ULTRAAQUA UV systems takes this into account. Disinfection is not the only UV application.

Ultraviolet lamp technology


UV is a spectrum of light that is just below the visible range to the human eye. The UV-C spectrum (185 – 280 nm) is known as the germicidal spectrum because it is the region that contains the peak germicidal wavelength (260 nm). The UV units for water treatment consist of a specialized low-pressure high output lamp with Mercury indium amalgam filling that produces ultraviolet radiation at 254 nm, very close to the optimum at 260 nm. Compared to the low-pressure lamps the medium pressure lamps are less efficient in utilizing usable germicidal wavelengths. Medium pressure lamps generally only convert up to 10% of their input watts into usable UV-C watts, whilst amalgam low-pressure lamps can be up to 40% efficient. There has been a drastic rise in market share for “low pressure-high intensity” amalgam lamps in the past few years. This has been primarily driven by the need for higher electrically efficient lamps (thus lower electrical operating costs) and the growing awareness in using “green” technologies to reduce carbon footprint.


UV system consists of a control cabinet and a UV reactor. While there are many UV systems in the industry today, the quality of its essential internal parts determines its performance. ULTRAAQUA UV systems uses the highest grade materials and components available on the market.



• Monochromatic spectrum
• Power density app. 0,5-5,5 W/cm
• Power levels 0-1000 W
• Efficiency 32-40%
• Lamp life times 8.000-16.000 H
• Lamp surface temperatures 40-130 °C



• Polychromatic spectrum
• Power density app. 100-500 W/cm
• Power levels 0.5 – 50 kW
• Efficiency 7-15%
• Lamp life times 1.000-9.000 H
• Lamp surface temperatures 600-800°C



The ULTRATHERM™ quartz sleeves are made from the highest purity quartz available and have an unlimited lifetime if not scratched or fouled. This guarantees excellent UV ray transmission and effective disinfection. It is exceptionally important to keep quartz sleeves clean as any fouling traps the UV light that can negatively affect the entire disinfection process. The suggested replacement interval is <24,000 hours.



ULTRATOUCH™ control cabinets are designed for installation in industrial environments. Their design reflects the “what you need to know when you need to know it” philosophy. With multiple features and enclosure material options, they can be designed specifically for a variety of applications and climates. All internal components are from the established European suppliers delivering smooth and energy-efficient operations.

Frequently Asked Questions

Your ultimate guide to UV technology

Even though UV technology has been around for over 100 years, its optimization and potential have been fully utilized only a few decades ago. Since then the use of UV technology experienced rapid growth and continuous development to achieve maximum efficiency in various water treatment applications. However, to this day, the majority of people, even in the water treatment industry have a lot of questions in regards to its efficiency, functionality, and benefits. Please use our FAQ guide to help you find answers for some of them:

Why UV disinfection is better than other water disinfection solutions?

Ultraviolet disinfection in most cases is the last step of the water treatment process, destroying the tiniest particles that cannot be filtered out by existing filters. UV disinfection is the only solution that does not change any properties such as its pH and temperature – which are extremely crucial for some applications like aqua life and ultra-pure water. It is also extremely effective in destroying microorganisms – there are no known bacteria or viruses that are resilient to UV light. Furthermore, microorganisms cannot build resilience against UV light. Lastly, technology today has been optimized to the point where UV systems usually are the best OPEX and CAPEX wide due to energy use, footprint, and high level of automation. It also requires the shortest contact time without the need for additional supportive infrastructure. Even though some of the alternatives solutions possess sections of UV technology advantages, only UV disinfection delivers them all at once.

What are the most common UV applications for water treatment?

Besides standard disinfection, the other most common UV applications for water treatment are:

  • De-chlorination: usually when the water in the inlet point has been pre-treated with chlorine and the further processes can not tolerate it and its by-products. Commonly found in high-purity water applications like injection water for food and beverage, pharmaceuticals, and microelectronics industries. Also extremely effective for swimming pool water.
  • De-ozonation: ozone can be sometimes used to clean up the entire piping systems and places that cannot be accessed by maintenance teams. However, ozone is highly chemically reactive and needs to be eliminated not to harm the end product in high-purity water environments or aquaculture species.
  • TOC destruction: in the drinking water industry, TOC is directly associated with THMs and HAAs formation when chlorine is used. By destroying TOC, the formation of dangerous microorganisms reduces significantly. Also very common in pharmaceuticals and microelectronics industries.
  • AOP: used in applications where the microorganisms are complex and cannot be destroyed by typical UV light, or where high purity water is required. The AOP process consists of UV and hydrogen peroxide or ozone, or both.

Can UV light kill covid-19 virus?

UV light has been proven to effectively eliminate the Covid-19 virus. Based on the latest research, the covid-19 virus cannot survive the whole water treatment path, therefore there is no actual need to treat drinking water from covid-19.

How often do I need to replace UV lamps?

The low pressure – high output ULTRATHERM™ UV lamps can be replaced every 16 000 hours (industry standard 12 000 hours), with medium-pressure ULTRATHERM™ UV lamps 9000 hours (industry average 8000 hours).

What UV intensity is needed to kill all bacteria and viruses?

This varies by industry and applications, but here are the averages:

  • Coliform bacteria, legionella, fecal bacteria, streptococci, nematodes (eelworms) and yeasts, etc. – 3 – 40 (mJ/cm²)
  • Pathogenic fungi, such as fusarium, pithium,Phytophtora, etc. – 30 – 120 (mJ/cm²)
  • Viruses such as cucumber virus, olpidium, cholera, etc. – 60 – 250 (mJ/cm²)


How is the right UV system selected for the project?

The most important factor in determining the right UV system is knowing the location, application, flow rate, UV transmission, and targeted bacteria (can also be tested in ULTRAAQUA UV laboratory upon sending the sample to HQ in Denmark). Providing desired log reduction and/or pre-filtration and generally as much information as possible can greatly assist in the company offering the most optimal options. The more information engineers have – the better-priced option they can offer to the requesting party.

What are the operation and maintenance costs for UV system?

Operation costs consist of the power supply that varies greatly depending on the UV system type.

The UV maintenance costs are the lowest possible compared to its alternatives. It is also safe without involving dangerous chemicals. Depending on the application, the inspection should be done annually, with lamp re-placement up to two years (medium pressure more often), and quartz sleeves up to four.

What pretreatment does UV system require?

This varies a lot based on applications and industries. The most important factor for the UV disinfection system is that UV rays are capable of “reaching” all pathogens in the flow-through water, meaning the water has adequate UVT (see below). The better-pretreated water is, the less UV light is needed and therefore more energy savings. However, ULTRAAQUA UV has developed multiple series for low-UVT environments that also are energy-optimized.

What is UVT and why is it important?

UVT is UV transmittance. It determines the UV light transmission factor in the water. All water can have particles invisible by the naked eye, yet capable of absorbing or deflecting UV light. That is why it is helpful to know water UVT when determining the right system size for the project.

Can I install UV system outside?

Yes, however, the control cabinet should be covered from direct sunlight or rainfall.

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