Dissolved Oxygen

Dissolved Oxygen is the level of free, non-compound oxygen present in water or other liquids. It is an important parameter in assessing water quality due to its influence on the organisms living within a body of water. Oxygen enters water through the air or as a plant by-product and is also produced as a waste product of photosynthesis from phytoplankton, algae, seaweed and other aquatic plants.

Oxygen levels in water can be expressed in units of concentration, as mg/L, or in relation to the maximum amount of oxygen that can be dissolved in the water at a certain temperature, called ‘% saturation’.

Measuring Dissolved Oxygen in water and treatment to maintain the correct levels is crucial within a variety of water treatment applications as it can affect quality, regulatory compliance and process control. Dissolved Oxygen water quality monitoring is critical for aeration system process control.

Monitoring Dissolved Oxygen and the temperature of the source water can provide early warning for seasonal rise in manganese concentration. High levels of DO accelerates corrosion in water pipes, whereas low levels can cause an increase in ferrous iron concentration, resulting in discoloration at the tap when water is aerated.