# How to Calculate Aeration Tank Air Quantity?

This example in connection with our previous post,

How to calculate Aeration Tank Volume?

Total BOD to be removed (Influent) = 250 mg/l (assume) x 1400  = 350 kg/Day (we consider 1400 M3/Day Effluent Plant)

Hence O2 to be transferred =350 kg/Day

Method of Aeration = Fine Bubble Diffuser

SOTE (Standard O2 Transfer Efficiency For 300 mm disc type diffuser submergence) =20%

Hence O2 required 350/0.20 =1750 kg/day.

Assuming alpha Factor (Ratio of SOTE in clean water to effluent water)=0.8 and

Another alpha Factor (Factor for fouling of diffusers) =0.8

Oxygen requirement =2734 kg/day {Oxygen % in the atmospheric air = 23.2%}

Hence, Air Requirement =11790 kg/day {With Sp.gravity of Air at 50°C =0.8 kg/M³}

Air requirement = 14737 M³/Day = 614 M³/Hr

Allowing 5% extra, So 650 M³/Hr @ 0.5 kg/cm2 blower can be select

further note below points too.,

one more point to be consider the Depth of aeration Tank,  suppose it is 4 metre depth select 0.5 or 0.6 kg/cm² in blower side.

### 76 throughts on "How to Calculate Aeration Tank Air Quantity?"

1. Uday Dixit says:

Thank Sir.

2. Shailendra says:

Excellent . Informative,

3. Jancy says:

The info is very useful . For my clarification, in Air requirement of aeration tank topic

Total BOD to be removed = 250 (assume) x 1400 = 350 kg/Day; What does 1400 denotes?
And for more details to know can you provide me the contact mail id. since I work in STP concern I like to know more about Calculation and process details from your website.

Thank you,

1. T.P.Sivanandan says:

1400 m3/day effluent to be treated

1. kvsr says:

Hence O2 required 350/0.20 =1750 kg/day.
Oxygen requirement =2734 kg/day {Oxygen % in the atmospheric air = 23.2%}
What is it?

2. Safdar Toor says:

1400 m3 is effulent flow / day

4. Pankaj says:

What is 1400 in this calculation

1. T.P.Sivanandan says:

effluent load 1400 m3/day taken to account.

5. P_rocks says:

Can you Please explain these calculations in detail

1. T.P.Sivanandan says:

now, check it again the post has been updated, thanks to drop the commands

2. khud hi samajh le na be. kyun dass raha hai yar dassan kha le lassan

6. maithili says:

Total BOD to be removed = 250 (assume) x 1400 = 350 kg/Day

what is 1400?

1. T.P.Sivanandan says:

thanks your point out – 1400 we consider as effluent qty in m3/day

1. anurag says:

Can you tell me roughly SOTE % for a tubular fine bubble (say 600 mm to 1000mm) & Disc Type Coarse Bubble(80mm, 150mm)?
Is there any thumb rule for calculating it?

1. subramani says:

How to find out this value? – explain

Oxygen requirement =2734 kg/day
Hence, Air Requirement =11790 kg/day

1. T.P.Sivanandan says:

2734 kg/day /23.2% (Oxygen % in the atmospheric air = 23.2%) = 11784 kg/day air

2. R.Manojkumar says:

Plant capacity

3. 1400 assuming plant capacity

1. T.P.Sivanandan says:

yes, this is plant capacity in example case we taken into account.

7. Harpreet singh says:

Nice information sir.thanks

8. Harpreet singh says:

Nice information sir.thanks but finally what is volume of aeration tanks??

9. Chetan Nimje says:

Sir what is 250 in this calculation

1. T.P.Sivanandan says:

250 is mg/l of effluent BOD (assume)

10. amit says:

Pls sir explain this calculation in detail

11. arjun says:

how to calculate 350mg/d o2

12. Dnyaneshwar Manal says:

Hi Sir,

Thank you for your valuable knowlege.

You have mention that Sp.gravity of Air at 50°C =0.8 kg/M³ , but this value is about 1.05 kg/M³

This will change the Air requirements,

Regards,
Dnyaneshwar

13. Ashok z Mehta says:

If aeration tank death is 5 metre then what capacity blower require and why?

14. jansHi says:

Does the submergence SOTE vary with the depth ?

15. sakib mir says:

i have mechanical areator , make gsd ar 511 model what its oxygen transfer rate

16. Shivnarayan singh says:

How come oxygen required-2734 kg/d,
How much O2 required for Per kg of BOD.
Plz elaborate.

1. T.P.Sivanandan says:

O2 required 350/0.20 =1750 kg/day.and use Two alpha factor efficiency i.e %sote and fouling of diffuser [(1750/80%)/80%].
KG of O2 required for carbonaceous BOD removal can range from 0.7 Kg/Kg BOD for high rate activated sludge with short detention of Biomass (low sludge age) up to 1.5 kg/kg BOD for extended aeration with long detention of Biomass (MLSS, i.e., (long sludge age) in the bio system,
we account 1kg/kg of BOD.
Hope, you will clear.

1. Sivakumar says:

Thanks ?

Sir useful information but what is mean by sote for submergence of diffuser and what is mean by fouling of diffuser

1. T.P.Sivanandan says:

Submergence mean depends on depth of aeration tank the the sote will vary more depth more percentage of oxygen transfer but increase air blower power,similarly fouling mean it affects air discharge due to excess of MLSS and other colloids in aeration tank.

What is the basis of the assumption of 0.8 for both alpha1 and alpha2.?

How can I determine it for other cases?

18. Yogesh Wani says:

What will be the % oxygen transfer efficienty for 1000 mm long x 67 mm OD fine bubble tubular air diffuser silicone basaed membrane

19. Vinoth says:

Dear Sir,
How to calculate BOD and Air quantity in Aeration Tank

20. jayababu says:

Dear sir,
if it is using jet aerators (30 hp) and blower(5 hp) then find the air producing rate per hour

1. T.P.Sivanandan says:

You can see the manufacturer catalog, model to model it will vary and depends on Depth of installation,the output air CFM vary, plz ask the supplier, normally @ 0.5 kg/cm2 pressure you can install that jet aerator upto 4 meter depth?

21. shamshuddin s kazi says:

Dear Sir,
Can u tell me how to calculate quantity of mbbr media required in stp/etp.

22. Rajiv says:

Mr.Shivanandan, what should be the optimum depth of aeration tank to get maximum SOTE ?
Regards

1. T.P.Sivanandan says:

suggested depth 4 to 5 meter, but SOTE ! influence many factor depth, bubble size, temperature of the medium, bubble travel either it travels direct upward from the bottom of diffuser or certain inclination / angels.

1. shamshuddin s kazi says:

Dear Sivanandan,
Can u tell me how to calculate quantity of mbbr media required in stp/etp.

23. venkayya soorubhotla says:

sir my air requirement is 650cum/h my aeration tank depth is 4mt how to calculate blower capacity

exactly my same question

24. Ajinkya says:

What will be efficiency need to take during actual purchase?

how can we select blower pressure?
here directly it is given to select 0.5kg/cm2.
on which factor we can select?

26. sanjeev Mishra says:

Please provided details calculation xygen requirement =2734 kg/day {Oxygen % in the atmospheric air = 23.2%}

Hence, Air Requirement =11790 kg/day {With Sp.gravity of Air at 50°C =0.8 kg/M³}

Air requirement = 14737 M³/Day = 614 M³/Hr

27. Kailas Hendre says:

Thanks sir ! Very useful information.

28. Anwar jamal says:

Sir please provide detail calculation for pipeline distribution and diffuser requirements for the above capacity

29. Manal Abdallah says:

thanks but I need how select the blower suitable ?

30. Purushothaman says:

Very useful Easy and detailed design calculation.thank you sir

1. T.P.Sivanandan says:

you are welcome

31. Manuj says:

Our aeration tank capacity is 95 cu.m x 3nos=285cu.m.Sir how can I find matching aeration pump capacity for this plant? Recently we have 3.7kw x 3nos submersible pumps.

32. Thushi says:

Thanks. What is the basis for calculating require aeration tank size, and diffuser qty

1. T.P.Sivanandan says:

Thank you

33. Sandeep says:

How did you get 2734 kg/cm2

34. Jazrul Hafez says:

Sir, for alpha factor, it is for clean water right? may i know how to calculate alpha factor?
Then for the O2 required in the calculation is the total oxygen supply by the blower to all diffuser in the aeration tank right?

35. Komal Khake says:

O2 requirement = 2734 kg / day how??

36. T.Nandakumar says:

90 KLD Sewage Treatment Plant how much capacity blower required

37. Anoop says:

From where oxygen req. 2724 kg /day came in calculation

1. T.P.Sivanandan says:

1750/0.8/0.8=2724

38. Maninder Preet Singh says:

Hello Sir,

I would like to Know that IF iwant to select the Air blower for MBBR tank as well as Eqt tank and Sludge tank then how to calculate the Air Requirement.

39. Mayur Limbasiya says:

How did you went from 1750 kg/day to 11790 kg/day pls give detailed step. Thanks for the information, looking forward for your reply

1. T.P.Sivanandan says:

Hi, 1750 is real O2 require, calculate 2 alpha factor 0.8 and 0.8 (1750/0.8 =2187.5/0.8=2734) further available oxygen in the air 23.2 %
so, divide 2734/0.232= 11784 so 11790 Air Require /Day(Don’t confuse this Air Quantity not Oxygen Qty)

Hope you understood well

1. AVIRAL TIWARI says:

What do you mean by alpha factor and how it’s calculated

40. Venkata Prathap.VN says:

So detailed. Thanks.

1. T.P.Sivanandan says:

You’re welcome

Can you tell me roughly SOTE % for a tubular fine bubble (say 600 mm to 1000mm) & Disc Type Coarse Bubble(80mm, 150mm)?
Is there any thumb rule for calculating it?

41. My STP capacity is 450KLD SBR model sir, what is the blower capacity I need to install..

42. VISHAL PATIL says:

If i have 300 BOD Effluent, and 200m³/day Treatment, then how much O2 required and what will be airation tank capacity, ?
What will be HRT..?

43. Suresh says:

Very useful information sir thank you for your information

44. Thanks for your article sir.
so, if we take O2 required 350/0.20 =1750 kg/day.
1750 kg/day / 350kg BOD,
its mean O2 requirement for 1 kg BOD is 5 kg.

45. Dr. D. Lakshmanan Formerly Principal Scientist CSIR-CLRI Chennai says:

Sir, my STP is (SBR – 65 KL – 3 batch / day) 0). The BOD is 230 – 5. How much oxygen is required and what is the motor capacity? please explain

46. mohamed Anwer hassan Aly says:

thank you very much