SOLUTION: Hi, I'm an engineer working in the area of environmental (wastewater treatment) and have a question which I hope you can help solve. We commonly provide air to biological tanks

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Question 307984: Hi, I'm an engineer working in the area of environmental (wastewater treatment) and have a question which I hope you can help solve.
We commonly provide air to biological tanks where we are attempting to infuse oxygen into the tanks via air (approx. 20% oxygen in air).
The devices which inject air into the basins vary in type and style but it is known that pushing the air into the basin in smaller diameter bubbles is better than larger diameter bubbles due to the larger surface area per unit volume found in smaller bubbles vs larger bubbles.
My question is this: Do you have a graph (or help me develop a graph) which shows the relationship of surface area to diameter of bubbles for a given cubic foot of air delivered to the basin?
Thanks for any help you can provide.
Don Voigt, P.E.
Port Washington, WI
Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website!
The relationship of surface area to diameter is constant for a spherical bubble.

However the bubble size distribution will depend on how the air in injected into the basin: pressure, temperature, depth, salinity, etc.. You may need to do some experimental work to find bubble diameter as a function of some of these parameters. Here's a link to a paper written to discuss bubble size distributions for different configurations of flow. It may be a good starting point.
http://www.springerlink.com/content/kebeyn0j76fynjml/

Also, check this link that discusses the use of venturis and injectors to produce microbubbles, exactly what I think you're looking for.
http://www.ozoneapplications.com/info/venturi_injection_vs_bubble_diffusers.htm
Good luck!