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Online UV and Vis Spectroscopy for Water Quality Monitoring

Reagent-free online monitoring for drinking water, wastewater and process water

Online UV and UV-Vis spectroscopy gives operators a fast, reliable and reagent-free way to understand water quality in real time. Instead of relying only on laboratory sampling, online optical sensors can continuously monitor key water quality parameters directly in the process, in a flow cell or at remote monitoring locations.

PMA supplies and supports advanced TriOS optical sensors for online water quality monitoring across drinking water, wastewater, environmental monitoring and industrial process applications. These sensors use proven UV absorption, spectral analysis and optical measurement techniques to provide continuous insight into nitrogen compounds, organic loading, UV254, SAC254, turbidity-related values and other important water quality indicators.

For water companies, industrial operators and process engineers, online UV and UV-Vis monitoring can support process control, event detection, compliance awareness, chemical dosing optimisation and operational decision-making.

TriOS OPUS UV spectral sensor for reagent-free online water quality monitoring in drinking water, wastewater, environmental and industrial applications.

OPUS

Multi-Parameter UV spectral sensor drinking water and wastewater treatment.

TriOS NICO plus online UV photometer for nitrate, NOx, SAC254, UVT254, COD equivalent and turbidity monitoring in water.

NICO PLUS

Multi-Parameter UV-Absorption Sensor for real-time nitrate, organic carbon, and UVT254 monitoring in water and wastewater applications.

TriOS LISA UV online SAC254 and UV254 sensor for UV transmittance, COD equivalent, BOD equivalent and TOC equivalent monitoring.

LISA UV

Advanced UV254 Absorption Sensor for real-time organic compound, TOC, and UVT254 monitoring in water quality applications.

Why use online UV and Vis spectroscopy?

UV and Vis spectroscopy are powerful techniques for monitoring water quality because many important substances absorb light at specific wavelengths. By analysing light absorption across selected UV or visible wavelengths, online optical sensors can provide continuous measurement of parameters that would traditionally require manual sampling or laboratory analysis.

Depending on the application and sensor configuration, UV and Vis monitoring can be used for:

  • Nitrate and nitrite monitoring
  • UV254 and SAC254 measurement
  • UV transmittance monitoring
  • Organic equivalent parameters such as CODeq, BODeq, TOCeq and DOCeq
  • Turbidity-related compensation and suspended solids indicators
  • Colour and visible-light attenuation measurements
  • Drinking water process monitoring
  • Wastewater process control
  • Environmental and catchment monitoring
  • Industrial water and process applications

The main benefit is simple: operators get continuous water quality data without reagents, without complex sample preparation and without waiting for laboratory results.

TriOS optical sensors for online water quality monitoring

PMA provides a range of TriOS online optical sensors that can be used for UV and UV-Vis water quality monitoring. The best sensor depends on the required parameters, water type, installation location, measuring range and process conditions.

TriOS OPUS

OPUS is a spectral UV probe for online measurement of nitrogen and carbon-related parameters in water. By analysing a full UV spectrum, OPUS can provide reliable online readings for nitrate, nitrite and organic equivalent parameters including CODeq, BODeq, DOCeq and TOCeq.

OPUS is well suited to applications where operators need a broader understanding of water quality from a single online optical sensor. Typical applications include wastewater monitoring, environmental monitoring, drinking water monitoring and industrial water quality applications.

Key parameters include:

  • NO3-N / nitrate
  • NO2-N / nitrite
  • CODeq
  • BODeq
  • DOCeq
  • TOCeq
  • TSSeq
  • SAC254

 

OPUS is particularly useful where real-time nitrogen and organic load monitoring can support process control, event detection and operational visibility.

TriOS NICO plus

NICO plus is a versatile UV photometer for nitrate and SAC254 determination, with additional water quality parameters available from the same sensor platform. It is designed for real-time online monitoring and can be used in sewage treatment plants, environmental monitoring, drinking water monitoring and industrial applications.

NICO plus is a strong option where nitrate monitoring is required alongside UV254, SAC254 and organic equivalent parameters.

Key parameters include:

  • NO3 / NO3-N
  • NOx / NOx-N
  • SAC254
  • UVT254
  • UVT254n
  • CODeq
  • BODeq
  • TOCeq
  • DOCeq
  • Turbidity
  • TSSeq

For sites that need online nitrate monitoring with additional UV absorption data, NICO plus provides a compact and reagent-free solution.

TriOS LISA UV

LISA UV is an innovative SAC254 and UV254 sensor designed for online water quality monitoring with low investment and low operating costs. It uses durable UV LED technology and can be configured for direct output of UVT, CODeq, BODeq and TOCeq using application-specific correlation.

LISA UV is particularly relevant for drinking water, wastewater, environmental monitoring and UV disinfection monitoring applications where operators need robust UV254, SAC254 or UV transmittance data.

Key parameters include:

  • SAC254
  • UVT254
  • CODeq
  • BODeq
  • TOCeq
  • Turbidity compensation

LISA UV is a practical choice for sites that need reliable online UV254 or SAC254 monitoring without reagents and without complex sample preparation.

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