How to size diffused aeration system for aeration process of raw water in the treatment plant

What is the design methodology to size the diffused aeration system to increase DO of raw water.

For example the common empirical formula to calculate the number of diffusion units to be installed? 

Taxonomy

• Aeration
• Waste Water Treatments
• Wastewater Treatment
• Wastewater Treatment Plant Design
• Moving Bed Biofilm Reactor (MBBR)
• Membrane Aerated Biofilm Reactor (MABR)

7 Answers

1. Any procedure by which oxygen is added to water can be considered a type of water aeration. This being the only criterion, there are a variety of ways to aerate water. These fall into two broad areas – surface aeration and subsurface aeration. There are a number of techniques and technologies available for both approaches.The bottom diffused aeration process introduces compressed air to a deeper part of the water column. A diffuser breaks the compressed air into fine bubbles. As the bubbles rise through the water column some oxygen from the bubbles is dissolved into the water.Different type of aeriation are used

   1. Natural aeration

   2. Low speed surface aerator

   3. Fountains

   4. Floating surface aerators

   5. Paddlewheel aerators

   6. Subsurface aeration

   7. Jet aeration

   8. Coarse bubble aeration

   9.  Fine bubble aeration

2. You could also use EPA Manual 

3. Dear Friend There is not a simple adequate method available to estimate the amount diffusers. Please, contact www.StamfordScientific.com, one of the leading aeration company. Br Paavo of Finntreat Oy

4. to get the best and accurate answer, pls go in contact with Enviplan

5. FLow rate of raw water, DO concentration in raw water, Desired DO level , calculate  the amount of air to deliver the target DO. DIvide this air by the capacity of each diffuser. I do not use empirical formulae.

6. You need to evaluate oxygen transfer rates on your stream and in the AB.  If this is a new build all of the manufacturers have software that will allow you manipulate different schemes to find the most efficient.  You will normally use fine/medium size diffusers for the microbubble creation, but will augment the mixing, if complete mix AS is your layout.  My suggestion is to be forward thinking for expansion and redundancy.  Back up blowers and a bulk tank of hydrogen peroxide (for upset conditions lowering DO) are in my opinion essential safeguards that prevent violations.  You lose about 1% active H2O2 a year in the proper tank protects from UV.  Cheap way to augment an overloaded system.  Thanks, Sean

7. Hey Nik, 

   you can find an example of how to calculate the required air volume here: https://youtu.be/MyiOL1jWcQw

   The amount of air per diffuser differs a lot by diffuser type but for standard disc diffusers its usually 1 to 2.5 SCFM per diffuser.