The amount of dissolved oxygen (DO) plays an important role in water quality and the livelihood of aquaculture. DO refers to the total amount of oxygen currently present in the water. DO is expressed in many different units, but most often in mg/L or % saturation (DO%). The unit mg/L is straightforward, as it is the milligrams of gaseous oxygen dissolved in a litre of water.
There are many reasons why it is important to evaluate the amount of DO in water. In a wastewater treatment plant, air is pumped into aeration tank to sustain microbes that break down contaminants. After leaving the primary treatment stage, sewage is pumped into aeration tanks. The sludge is loaded with microorganisms and mixed with air or pure oxygen. As air is forced into the aeration tanks, it increases the activity of these microorganisms and helps keep the organic waste thoroughly mixed. DO is added to the aeration basin to enhance the oxidation process by providing oxygen to aerobic microorganisms so they can successfully turn organic wastes into inorganic byproducts.
DO sensor are commonly used for field sampling and long-term monitoring applications along with DO meter, analyzer or control system. Optical DO sensors is called luminescent DO sensors or fluorescent sensors, where dissolved oxygen concentration is measured based on the quenching of luminescence in the presence of oxygen.
- Light-emitting diodes (LEDs): Blue LED emits light that excites the dye causing its luminescence. The red LED emits light but simply reflected by the dye and does not cause luminescence. It serves as a reference to ensure accuracy.
- Photodetector: photodiode measures the intensity or lifetime of luminescence from the dye.
- Luminescent dye: Luminescent dye is entrapped in the sensor film. When exposed to blue light, the dye becomes excited (electrons gaining energy) and emits light as the electrons return to their normal energy state.
- Membrane
IUNI-21 2-Channel Dissolved Oxygen Analyzer
- RS485 signal output
- Stable data and good repeatability
- Strong anti-interference ability
- Fast response time
- Low maintenance cost
- Suitable for regulating reservoir, biochemical pool, effluent of sewage treatment plant, surface water, industrial process water, aquaculture, etc.
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Bamowiz 452 Dissolved Oxygen Monitor
- Graphic color touch-sensitive screen
- Dissolved oxygen monitoring: 0 to 20 mg/l ; 0 to 500 %
- 1 Input for Bamox 453 probe
- 1 analogue output 0/4-20 mA
- 3 relays (Trigger points, Alarm)
- 2 analogue inputs 4-20 mA
- Applications:
- Urban wastewater treatments (nitrifying / denitrifying process)
- Treatment of industrial effluents
- Monitoring of surface waters, coastal waters, aquariums
- Fish farming and aquaculture (fresh water, sea water)
- Drinkable water
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