Water Quality - CDOM Monitoring

Coloured dissolved organic matter (CDOM) is the optically measurable component of the dissolved organic matter in water. Also known as Gelbstoff, CDOM occurs naturally in aquatic environments primarily as a result of tannin-stained waters released from decaying detritus. CDOM most strongly absorbs short wavelength light ranging from blue to ultraviolet, whereas pure water absorbs longer wavelength red light. Therefore, non-turbid water with little or no CDOM appears blue. The color of water will range through green, yellow-green, and brown as CDOM increases.


CDOM MonitoringThe CDOM-Station system enables in-line, real-time, reporting of Coloured Dissolved Organic Material (CDOM) within both water processing plants and natural water systems. The monitor detects Fluorescent Dissolved Organic Matter (FDOM) providing highly sensitive CDOM measurements that have been shown to correlate with organics within the water. These systems can inform on assessing organic load through a works, managing disinfection by-product formation potential, coagulation control and filter management.


Applications for the CDOM-Station include:

  • Managing disinfection by-product formation potential
  • Assessing organic load through works
  • Filter management
  • Coagulation Control
  • Monitoring THM and HAA precursors



What effect does CDOM have on the environment?
CDOM can have a significant effect on biological activity in aquatic systems. CDOM diminishes light as it penetrates water. This has a limiting effect on photosynthesis and can inhibit the growth of phytoplankton populations, which form the basis of oceanic food chains and are a primary source of atmospheric oxygen. CDOM also absorbs harmful UVA/B radiation, protecting organisms from DNA damage.

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