Dissolved oxygen probe

The Hach LDO luminescent dissolved oxygen probe is used in the measurement of dissolved oxygen (DO) in the water and wastewater treatment plant process.

Features include: no membranes; no electrolyte solution to replenish or replace; no anode or cathode to clean or replace; simple maintenance - periodically wipe the sensor tip clean; and reduced calibration frequency.

The probe can be used in many places throughout the wastewater treatment process, such as aeration basins, aerobic and anaerobic digesters and nitrification and de-nitrification tanks.

It uses a sensor coated with a luminescent material. Blue light from an LED is transmitted to the sensor surface and excites the luminescent material, which emits red light as it relaxes.

The time from when the blue light was sent to when the red light is emitted is measured. The more oxygen that is present the shorter the time it takes for the red light to be emitted. This time is measured and correlated to the oxygen concentration.