How UV technology works

BASICS OF UV LIGHT TECHNOLOGY

UV technology has a long history of over 100 years and has since then experienced a thorough utilization of the technology’s potential. The method is based on the natural disinfection action of the sun’s rays. UV lamps imitate the disinfecting rays of the sun. UV systems produce the same ultraviolet germicidal rays, just thousands of times stronger. No bacteria, viruses, molds, or spores are able to withstand this treatment, making ultraviolet technology a globally accepted solution for water disinfection.

The use of UV technology effectively ensures that the water quality, both physical and chemical, remains identical before and after the treatment. Additionally, 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. These are some of the advantages that makes UV technology systems the preferred solution in a wide range of water treatment applications.

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 the measure of the UV light’s ability to pass through 1 cm of liquid. When light irradiates the water, the water absorbs a part of the radiation, resulting in a decrease in light intensity from the lamp. The design of ULTRAAQUA UV systems takes this into account, being easy to install, maintain and thoroughly cost-optimized.

Ultraviolet lamp technology

LOW PRESSURE VS. MEDIUM PRESSURE UV LAMPS

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 primarily been driven by the need for higher electrically efficient lamps (thus lower electrical operating costs) combined with the growing awareness in using “green” technologies to reduce carbon footprint.

THE CORE OF THE UV SYSTEM

UV systems 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 use the highest-grade materials and components available on the market.

ULTRATHERM™ LOW PRESSURE – HIGH OUTPUT UV LAMPS (LPHO)

ULTRATHERM™ LOW PRESSURE – HIGH OUTPUT UV LAMPS (LPHO)

• 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

ULTRATHERM™ MEDIUM PRESSURE – HIGH OUTPUT UV LAMPS

ULTRATHERM™ MEDIUM PRESSURE – HIGH OUTPUT UV LAMPS

• 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

ULTRATHERM™ QUARTZ SLEEVES

ULTRATHERM™ QUARTZ SLEEVES

The ULTRATHERM™ quartz sleeves are made from the highest purity quartz available. If they are not scratched or fouled, they have an unlimited lifetime. This guarantees excellent UV ray transmission and effective disinfection. It is essential to keep the quartz sleeves clean as any fouling can trap the UV light, resulting in a negative impact on the entire disinfection process. The suggested replacement interval is <24,000 hours.

ULTRATOUCH™ CONTROL CABINETS

ULTRATOUCH™ CONTROL CABINETS

ULTRATOUCH™ control cabinets are designed for installation in industrial environments. The 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 established European suppliers, delivering smooth and energy-efficient operations.

Frequently Asked Questions

Your ultimate guide to UV technology

Since the technology was invented over 100 years ago, the use of UV technology has experienced rapid growth and continuous development to achieve maximum efficiency in various water treatment applications. Today, the potential and advantages of the technology are hard to ignore for the many available water treatment applications. In the guide below, you can find answers regarding its efficiency, functionality, benefits and more.

Why is UV disinfection often the preferred water disinfection solution?

In most cases, ultraviolet disinfection 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 pH and temperature – which is essential for applications such as aqua life and ultra-pure water.

Ultraviolet disinfection is extremely effective in destroying microorganisms, since no known bacteria or viruses are resilient to UV light. Furthermore, the technology today is optimized to a point where UV systems are usually the best OPEX and CAPEX wise 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 alternative 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 cannot tolerate it and its by-products. Commonly found in high-purity water applications like injection water for food and beverage, pharmaceuticals, and microelectronics industries. It is also extremely effective for swimming pool water.
  • De-ozonation: ozone can sometimes be 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, in order 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 is reduced significantly. It is 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, ozone, or both.

Can UV light kill COVID-19 virus?

UV light has been proven to effectively eliminate the Covid-19 virus. However, based on the latest research, the covid-19 virus cannot survive the whole water treatment path. Because of this, 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 9 000 hours (industry average 8 000 hours).

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

The UV intensity requirement varies a lot, based on industry and applications. 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 do I select the right UV system?

Some of the most important factors in determining the right UV system are knowing the location, application, flow rate, UV transmission, and targeted bacteria. ULTRAAQUA is able to assist in assessing all of the factors to ensure that the right UV system is chosen. By sending a sample to our headquarters in Denmark, we can help with assessing the bacteria to be targeted in our state-of-the-art laboratory.

By providing the desired log reduction and/or pre-filtration we can help find the perfect solution for your needs. The more information engineers have, the better product fit and pricing can be offered to the requesting party.

What are the operation and maintenance costs of a UV system?

Operation costs are based on the power supply, which can vary greatly depending on the type of the UV system.

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 years.

What pretreatment does a 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 UV Transmittance and why is it important?

UVT is short for UV transmittance. UV transmittance determines the UV light transmission factor in the water. Even though it is not visible to the human eye, all water is capable of having particles that absorbs or deflects UV light. The UVT is necessary to know in order to ensure proper water disinfection. UVT is a measurement of the amount of ultraviolet light at 254 nm that passes through a water sample. The measurement is expressed as a percentage – %UVT.

UVT can vary over time and from site to site as it relates to the quantity of organics, colloidal solids and other material in the water which absorbs the UV light as it passes through the water column. The effective UV dose is dependent primarily on the combined effects of the UV light intensity, the exposure time and the UVT. Different pathogens require different amounts of UV energy to inactivate them. Therefore, it must be clear which pathogens are to be inactivated for any UV system.

When dealing with pathogen inactivation, it is important to note that the relationship between the dose and the log removal is not linear. It takes a much higher dose to achieve log-4 removal compared to log-2 removal. Please consult one of our specialists if you are in doubt about specific UVT values.

Can I install a UV system outside?

It is possible to install a UV system outside, however, the control cabinet should be covered from direct sunlight or rainfall.

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