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).

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.

Why is UVT Measurement Needed?

UV Transmittance measurements provide valuable information related to the amount of natural organic matter (NOM) in the water sample. Data characterizing the organic contents of the sample water can be used to control and optimize both water and wastewater treatment processes. Generally, UVT measurements are used to optimize energy efficiency and to ensure adequate dosage by the UV disinfection system. UV dosage is dependent on the UV light intensity, contact time (which is controlled by flow rate), and UVT. Most UV disinfection systems are programmed for a 4-20 mA input of UVT to balance lamp intensity for the system meeting the dosing requirements.

Common Applications:

UV disinfection performance optimizing in wastewater
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
SMARTER UV-TRANSMITTANCE MONITORING

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UVT-LED-SW

Online UV Transmittance Monitor

Continuous Monitoring Delivers UV Disinfection Optimization
Versatile Design Allows for Submersion or In-line Configuration
Automatic Cleaning & Calibration
Free Factory Scheduled Maintenance for the First Year

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UVT-LED-H

Handheld/Portable UV Transmittance Monitor

Obtain UV Transmittance Measurements Anywhere
Verify Online UVT Sensor Performance
Zero Warm-up Time
Simple Push Button Operation

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TECH SPECS

Power: 24 VDC, Output: 4-20mA

Size & Weight: 9.40″H x 3.00″ Dia, 1.78 lbs (0.81 kg)

Measurements: Range: 10% – 100% T;
Interval: 60 seconds

Measurement Path Length: 1cm

Maintenance: Factory scheduled maintenance every 6 months, free for the first year

Accuracy: 1.0% T

Resolution: 0.1% T

Display: Optional 4-20mA Display (Sold Separately)