Increasing Oxygen in Wastewater - How to Achieve Aeration
Aeration is exposing wastewater to the atmospheric oxygen.
Excellent aeration in wastewater is achieved by: A) Increasing the area of contact between water and air (water sprayed in small droplets as done in cooling towers gives good exposure).
B) Agitating the surface of the liquid constantly to minimize the thickness of liquid film.
C) Increasing the contact time of water with air (for example, we can increase the height of the jet in a spray aerator).
There are many devices to increase oxygen in wastewater.
The popular ones are: a) Cascades b) Splash trays c) Shallow beds of coke or similar crushed material on which water will fall (which effects both adsorption and aeration).
d) Perforated pipes or porous plates through which, water is diffused.
'Local conditions', 'quality of water to be treated' and 'what is sought to be removed from or added to the water', determine aeration methods of wastewater treatment process.
Aeration however increases the oxygen content of wastewater, which may not be always desirable.
For example, the increased oxygen in wastewater may accelerate corrosion and algae growth.
Aeration has also been found to be not so effective in improving taste and odor.
These days, there are some good chemical methods available to achieve a better taste and odor.
For example, adding chlorine or activated carbon to the aeration systems is found to be very effective.
Chemical dosing and mixing Chemicals are introduced into the wastewater to aid the following: a) Coagulation b) Flocculation c) Disinfection d) Softening e) Algae control f) Corrosion control g) Fluoridation Chemicals are added continuously as solutions or dilute suspensions, with the help of chemical feeders (solution feed type or dry feed type).
Excellent aeration in wastewater is achieved by: A) Increasing the area of contact between water and air (water sprayed in small droplets as done in cooling towers gives good exposure).
B) Agitating the surface of the liquid constantly to minimize the thickness of liquid film.
C) Increasing the contact time of water with air (for example, we can increase the height of the jet in a spray aerator).
There are many devices to increase oxygen in wastewater.
The popular ones are: a) Cascades b) Splash trays c) Shallow beds of coke or similar crushed material on which water will fall (which effects both adsorption and aeration).
d) Perforated pipes or porous plates through which, water is diffused.
'Local conditions', 'quality of water to be treated' and 'what is sought to be removed from or added to the water', determine aeration methods of wastewater treatment process.
Aeration however increases the oxygen content of wastewater, which may not be always desirable.
For example, the increased oxygen in wastewater may accelerate corrosion and algae growth.
Aeration has also been found to be not so effective in improving taste and odor.
These days, there are some good chemical methods available to achieve a better taste and odor.
For example, adding chlorine or activated carbon to the aeration systems is found to be very effective.
Chemical dosing and mixing Chemicals are introduced into the wastewater to aid the following: a) Coagulation b) Flocculation c) Disinfection d) Softening e) Algae control f) Corrosion control g) Fluoridation Chemicals are added continuously as solutions or dilute suspensions, with the help of chemical feeders (solution feed type or dry feed type).
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