Safe recirculator. What is it like?


UV lamps do utilize mercury to generate germicidal ultraviolet radiation. But UV mercury lamps can be safe or dangerous.

Many recirculators are equipped with low-pressure mercury UV lamps. They contain mercury in liquid form. When the lamp is destroyed (broken), liquid mercury can get to a room and then can vapor into the air, which is very dangerous. In this case, demercurization of the room is required.

Modern recirculators utilize a new generation of UV lamps - amalgam lamps. They contain mercury in the form of amalgam (a hard alloy of mercury with other metals). When the lamp is destroyed, liquid mercury does not get out, but remains in the amalgam. In this case, demercurization is not required and mercury pollution of the room is impossible.

Moreover, waste amalgam lamps fall under hazard class III (FCCW code 471 102 11 523), compared to standard mercury UV lamps or fluorescent lamps, which are classified as waste of the hazard class I.


Strong UV radiation at a wavelength of 180-280 nm is dangerous for humans, animals and plants. It can cause damage to eyes, unprotected skin and plant leaves. The design of recirculators shall provide special solutions to prevent UV leaking light emission from UV chamber since recirculators is intended to operate in occupied areas.

When selecting or using a recirculator, make sure that the device does not glow in the dark, i.e. there is no so-called illumination.

UV radiation is invisible and the human eye cannot detect when it slip from a recirculator\ the light emission. That is why it is much safer if the device operates without any illumination.


Recirculators can be installed in rooms with small children. Keep the children from getting too close to a recirculator and do not let them put their arms or any object into it. This may be dangerous due to rotating fan and possible occurrence of UV irradiation.

Application of the knowledge about UV equipment, in particular about the recirculator, ensures its comfortable and safe usage.

← Back to news

Ultraviolet technology for water, air and surface disinfection is based on germicidal effect of UV-C radiation. 

UV radiation is electromagnetic radiation between x-rays and visible light. UV wavelengths range from 100 to 400 nanometer.

The UV wavelengths are divided in 4 groups, each with a different germicidal effect – UV-A (315–400 nm), UV-B (280–315 nm), UV-C (200–280 nm) and Vacuum UV (100–200 nm).

Ultraviolet in

Within the UV spectrum, UV-C range is considered the strongest UV radiation, which is easily absorbed by DNA, RNA and proteins. This range is often called germicidal due to its high disinfection efficiency against bacteria and viruses. The highest germicidal effect occurs at 205-280 nm and the maximum germicidal sensitivity of microorganisms at 265 nm. 

The germicidal effect is based on photon absorption by DNA and RNA molecules. Photochemical reaction provokes dimerization of DNA and RNA bonds, which inhibits the ability of microorganisms to replicate. This process is known as inactivation of microorganisms.

Mechanism of
UV disinfection

UV disinfection technology can be applied for potable water supply, wastewater treatment as well as for air and surface disinfection applications.

The major advantages of this technology:

  • high efficiency against a wide range of microorganisms including chlorine resistant ones (viruses and protozoa oocysts);
  • no impact on physical, chemical and organoleptic properties of water and air; no by-products; no dangerous overdosing;
  • low capital costs, power consumption and operational costs;
  • UV systems are compact and easy to operate; no need for special operational safety precautions.

Main industrial available sources of UV radiation are low pressure amalgam lamps and mercury medium pressure lamps. Medium pressure lamp technology have higher power per lamp (several kW) but significant lower efficiency (9-12%) in comparison to low pressure lamp technology with efficiencies between of 35-40% and power per lamp up to 1000 watt.

UV systems equipped with amalgam lamp technology generally have a little larger physical footprint but they are significantly more energy efficient.

The design of UV application depends on the required UV dose, flow rate and physical and chemical parameters of media to be disinfected. The facility design criteria, flexible, economical and sustainable operation are also the decisive design parameters.