ENDRESS+HAUSER  CAS51D-AAA1A2

Photometric sensor for SAC or nitrate measurement

SAC measurement

• Organic load in WWTP inlet
• Organic load WWTP outlet
• Discharger monitoring
• Organic load in drinking water

Nitrate measurement

• Nitrate measurement in natural bodies of water
• Monitoring nitrate content in WWTP outlet
• Monitoring nitrate content in aeration basins
• Monitoring and optimizing denitrification phases

• Affordable, environmentally friendly product
  • No complicated sampling and treatment
  • Chemical-free measurement
  • Low-maintenance
• Data conditioning in the sensor
  • Minimum sensitivity to interference during signal transmission
  • Short response time
• Early, continuous detection of load peaks without delay
• Ready for use thanks to factory calibration
• Standardized communication (Memosens technology) enables "plug and play"
• Very long maintenance intervals thanks to compressed air cleaning
• Customer calibrations with 1 - 5 points (max.) - in the lab or at place of installation

The light from a pulsed, high-stability strobe lamp (item 3) passes through the measurement section 1) (item 2). A beam splitter (item 6) directs the light beam to the two receivers (items 1 and 5). A filter upstream from the receivers only lets through light in the measuring wavelength or reference wavelength.

Within the measurement section, the medium in the cuvette (water, dissolved substances and particles) absorbs light across the entire spectrum. In the measuring wavelength range, the measured component 2) takes an additional part of its energy from the light.

The ratio of the light signal of the measuring wavelength to the light signal of the reference wavelength is used to calculate the measured value.

• If only water and turbidity are present, both signals are attenuated to the same degree and the ratio remains constant.
• If the medium contains the measured component, the signal of the measuring wavelength is attenuated more and the ratio changes.

This change in the ratio can be converted to determine the nitrate concentration or the SAC value. This dependency is non-linear.