UV Transmittance (UVT)
What is UV Transmittance (UVT)?
UV Transmittance, also known as ultra violet transmittance, refers to the percentage of light that passes through a water sample at the wavelength of 254 nm. UVT relates to the organics, colloidal solids, and suspended particles that absorb and scatter this UV light wavelength. The amount of UV light absorbed by the sample is known as the UV Absorbance (expressed as A254). Absorbance and transmittance are relevant by this logarithmic function A = log 10 (1/T).
Why is UVT Measurement Necessary?
The measurement provides valuable insight to the suspended solids and organics content in the water sample, and is a parameter used in the dose calculation for UV disinfection systems.
Dose control in drinking/processing water
Size and design of UV disinfection systems
Selection of the optimal disinfection treatment process
Disinfection by-product (DBP) formation potential upstream to chlorination
Micropollutant removal efficiency of wastewater treated with ozone
Optimize chemical dosing for turbidity and organics removal
Source water quality monitoring the drinking water treatment plant
Filtration membrane protection from biofouling
How is UVT Transmittance Measured?
Ultraviolet (UV) light, at the wavelength of 254 nm, is passed through a path of a 1cm water sample. Compared to a light intensity being measured in pure water and displaying a percentage, the intensity of the light is measured beside a photodiode.