Different microorganisms and viruses require different UV-C doses for a reliably disinfection. To keep it simple and secure – talking about standard potable water applications: A dose of 400 J/m² has become the standard in most European countries. This dose is expected to reliably inactivate 99,99 % of common waterborne pathogens.

The most important factor describing water quality in UV-C treatment is transmittance. The transmittance value of the water indicates the permeability of UV-C radiation with a wavelength of 254 nm, expressed in percent, that passed the water perpendicular. The design of the treatment chamber (shape, size, number of lamps) determines for which type of water quality (read UV-C transmittance) the system can be used.

What about Turbidity?
In some cases the turbidity is confused with the transmittance of the water. The turbidity of the water influences the transmittance of the water, but the transmittance does not affect the turbidity.

Different types of water generally have different qualities that can be expressed as UV-C transmittance ranges. In general you can say the lower the transmittance, the lower the water quality. The table below shows general values, however these are not set and can vary widely. A user should always be sure what the UV-C transmittance is, this needs to be measured by taking samples for each individual case.

Validation/certification of UV systems by 3th party test facilities gives the user certainty about the functioning of the UV system within the tested working area.
Water disinfection is, by definition, the process of eliminating, inactivating, or killing pathogenic microorganisms (bacteria, viruses, protozoa) in water to render it safe for human consumption.

For this reason, it is crucial to be certain that the UV system in use performs as intended. One of the most reliable ways to confirm that a system delivers the claimed safety and performance is through proper evaluation. This can be carried out either by an independent third party or on-site by the system owner or operator.

When you use water for drinking or in critical (production) processes, in terms of clean and safe water only 100% certainty counts. By monitoring the flow through and UV-C intensity in the UV-C system, you can guarantee the operational safety of your disinfection system. This allows for optimization of energy consumption and guarantees safety. If the system deviates from the set specified/certified/validated working range, the system can generate alarms and the water flow can be shut off.

The final and most important component of any UV-C system is the UV source that generates the UV-C light. Any benefits in performance, efficiency and safety originate here. The choice of UV-C source not only influences the energy consumption and maintenance requirements, but also total cost of ownership and environmental impact over the system’s lifetime. Also, the choice between monochromatic and polychromatic UV-C light depends on your application’s needs.