Ultraviolet Transmission (UVT)

Ultraviolet Transmission (UVT) is a measurement of UV-light absorbed which has not been absorbed within the water. When using UV-light at the specified wavelength of 254nm, it is a well-known tool with a history of use in clean and wastewater applications (EPA method 5910B). In essence, UVA and UVT% represent the same data presented using different, but related, mathematical treatments.

Although the raw data used to generate both parameter outputs are the same, the information they provide is different. UVT represents the amount of light transmitted through a sample stream (light energy that reaches the detector) and therefore defined as UV transmittance. In practice, which parameter used is determined by what information the user needs. For instance, UVA is commonly used as an indicator of general water-quality or the potential for disinfection by-product formation, whereas %UVT is more commonly used to gauge lamp intensity requirements for UV-disinfection.

LiquID’s advanced approach to UVA, %UVT and Turbidity 
The ZAPS LiquID Station’s unique design and hybrid multi-spectral output provides several advantages toward improved UVA, %UVT and Turbidity monitoring:

  • By delivering light directly to the fluid being analyzed the need for corrections at media interfaces  (such as light passing through variable distances of air or at cuvette surfaces) and variations introduced by different sample cells are eliminated.
  • The use of a single light source and detector allows component degradation, such as signal decay due to fouling, to be easily tracked and corrected for on all parameter outputs eliminating the effects of variable fouling on different probes within a probe array.
  • Board spectrum analysis and multi-parameter output allows for correction due to interferences such as the impact turbidity has on a UVA or %UVT measurement (and other absorption based outputs).
  • Parameter Detection Range/Sensitivity Accuracy
    Ultraviolet Transmission 0.2 to 100% ±5%

  • To learn more about the optical approach used by the LiquID to measure UVT please read the How It Works – UVT located in the Library and Resources section of our website.
  • Case Study – Real-Time E.coli Ultraviolet Control
  • Please Contact Us if you have additional questions about measuring UVT or general inquires into the LiquID Station.