UV narratives & misconceptions
UV technology is widely used in water treatment, yet it is often surrounded by persistent misconceptions. From questions about safety and effectiveness to concerns about mercury and energy use, these narratives can obscure the real value of UV-C disinfection. This article separates fact from fiction, providing clear, evidence-based insights into how UV technology works and where it truly makes a difference in delivering safe and sustainable water treatment solutions.
Effectiveness
| ❌ Narrative | ✅ Fact |
| “UV removes all contaminants” | UV inactivates microorganisms and plays a critical role in water treatment delivering reliable disinfection. Whilst UV is used as a standalone disinfection treatment option, you will usually find it working in a combination with other treatment steps. > Sitations where UV is preferred |
| “More UV power always means better disinfection” | The effective UV-C dose for your water treatment depends on the UV-C intensity (UV-C power) and the exposure time. The intensity depends on the quality of the water that you want to treat (the UV-C transmittance). > UV dose and dose distribution |
| “UV treatment in swimming pools reduces the effectiveness of chlorine” | UV technology only breaks down chloramines or combined chlorine compounds. These pose health risks to those exposed to them and also the corrosive nature of chloramines damage swimming pool infrastructure and HVAC systems. UV doesn’t effect the chlorine itself. >Chlorine distruction and resistance |
Safety
| ❌ Narrative | ✅ Fact |
| “UV is unsafe” | As with all UV technologies, exposure to UV-C radiation must be avoided; therefore, reactors are designed as closed systems with safety interlocks. > Safety during operation |
| “Regulators won’t approve UV disinfection without significant validation and pilot testing.” | There are internationally accepted standards for UV systems. Certified and validated UV systems use biodosimetry as a performance-based test to determine the validated UV dose and safe operating limits of the UV-C system. > Standards for UV disinfection systems |
Mercury & environment
| ❌ Narrative | ✅ Fact |
| “The mercury contained inside the UV lamp presents a hazard to end-users (or surface waters).” | UV lamps contain very small amounts of mercury (< 15 mg of Hg). Mercury is sealed in solid amalgam form, not free liquid. Systems are designed to prevent release to consumers, even during failure
Even if exposure occurred, for example in a worst-case scenario when all lamps would break in a treatment plant, the dose would be thousands of times below health limits. The actual exposure would still be negligible—far lower than common dietary sources like fish. |
| “Mercury contained inside the UV lamp presents an environmental hazard” | Mercury in UV lamps does not harm the environment. The mercury is sealed in solid amalgam form and does not escape into the air. Lamps are collected and recycled, and production often uses recycled mercury—creating a closed and controlled lifecycle. The worldwide consumption of (recycled) mercury for use in UV lamps is estimated around 70 kg annually (0,00002%), of which 50 kg is entering the EU market —equivalent to just 0.00002% of global mercury flows. > Mercury content and recycling |
| “Lamps break frequently and release mercury to the environment.” | UV lamps rarely break. In a study of Trojan, which has thousands of municipal drinking and wastewater systems installed worldwide, there were no lamp breaks recorded in one year (2025). |
| “UV LEDs are more environmentally compared to UV lamps friendly because they contain no mercury” | While UV LEDs are mercury-free in design, this does not mean they have a lower environmental impact. According to a 2025 study published in Nature Communications (Qiu et al., 2025), the main sources of global mercury emissions are:
In fact, over 50% of the world’s electricity is still generated from burning fossil fuels—one of the largest contributors to atmospheric mercury. Because UV LEDs are significantly less efficient than traditional low-pressure mercury lamps—often using up to 5× more energy for the same UV dose—their indirect mercury emissions (via electricity production) are actually higher. |
| “UV Mercury lamps contribute to worldwide mercury pollution” | The world production of Mercury was 1.160 ton in 2022. The worldwide emissions in 2021 was estimated at 2500 tons. The worldwide consumption of (recycled) mercury for use in UV lamps is estimated around 70 kg annually (0,00002%), of which 50 kg is entering the EU market > Mercury content and recycling LEDs do contain gold:
The gold mining industry is the biggest emitter of HG worldwide, with an estimated HG emission of 248–838 tonnes of Hg each year. |
| “Primary mining bans in 2023 are going to result in a lack of availability of mercury which means no more lamps or price spikes” | Banning primary mercury mining does not cause shortages or price spikes for UV lamps. Since 2018, the collection rate of gas discharge lamps has exceeded production. UV lamps use very small amounts of mercury, which is recycled and reused in a closed-loop system. Supply remains stable and independent of new mining. |
| “Mercury is phased-out in UV systems because of the EU Mercury Regulation (EU2024/1849)” | UV lamps are considered vital for producing safe and clean water. Therefore ‘Mercury in lamps emitting light in the ultraviolet spectrum’ have received an exemption on Hg use in the EU regulation (called the RoHS exemption). At the moment, the EU Mercury Regulation is being updated and this renewal loop is expected to take about 7 years. In the new RoHS renewal request, the HG exemption consists of 32 kg annually, for the EU. |
Energy consumption & UV LED's
| ❌ Narrative | ✅ Fact |
| “UV disinfection requires an excessive amount of energy.” | UV light consumes relatively little energy, especially when using efficient, validated designs. No chemicals or high pressure pumping systems are required. The footprint mainly depends on the energy source, and the efficiency of the UV sources and the treatment chamber design. How to use UV technology |
| “UVLEDs slash energy usage compared to Low Pressure UV lamps” | LEDs have 2-8% efficiency, where Low-pressure UV lamps have 30-40%. UV-C LED’s also produce very limited optical output, today, this is typically around 0.01 – 0,3 W per single UVC-LED. This means LED’s use at least 5x more energy compared to low-pressure UV lamps > UV sources compared |
| “UVLEDs run cooler and foul less than Low-pressure UV” | LEDs have a lower energy efficiency and product more heat when on. Low-pressure: 35% UVC = 65% heat LED: 7% UVC = 93% heat. With continuous flow, fooling caused by heat is unlikely. > low-pressure UV lamps |