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Into the Future with Metrology - The Challenges of Our Environment and Climate


UV therapy for safe drinking water

DVGW test laboratory
Measurement campaign at the DVGW test laboratory in St. Augustin-Meindorf for the validation of the calibration methods developed by PTB

Drinking water disinfection with UV-C radiation plays an increasingly important role in water treatment in order to reduce water pollution with chlorine, the substance most frequently used for this purpose worldwide. Due to the close cooperation between PTB and the Technologiezentrum Wasser (TZW) (the certification body responsible for Germany), traceable measuring and calibration methods have been established and laid down in standards (DIN 1294). Today's technology used to this end is mainly based on the use of mercury vapor lamps whose strong emission lines in the UV-C are close to the maximum of the action function for killing microorganisms. However, as the Minamata Agreement on mercury – which was initiated by the United Nations Environment Programme and ratified by all members in 2017 – provides for worldwide bans and restrictions on the manufacture, trade and sale of mercury-containing products from 2020, a technological change from mercury vapor lamps to LED-based energy-saving UV-C sources will take place in the coming years. Nevertheless, the new technology also requires a comprehensive adaptation of regulations and standardization and the acquisition of new scientific knowledge. For example, the spectral action function for killing microorganisms by UV radiation must be determined very precisely in order to adapt to it the spectrum of the UV LEDs that have to be used in the best possible way. Here, again with its partners and DIN, PTB is in the process of defining the metrological boundary conditions for appropriate sources.

Participating department
Opens internal link in current window4.1 Photometry and Spectroradiometry