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 O_{2 }to be transferred =350 kg/Day

Method of Aeration = Fine Bubble Diffuser

SOTE (

Standard OFor 300 mm disc type diffuser submergence) =20%_{2}Transfer Efficiency

Hence O_{2} 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.

Thank Sir.

Excellent . Informative,

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,

1400 m3/day effluent to be treated

What is 1400 in this calculation

effluent load 1400 m3/day taken to account.

Can you Please explain these calculations in detail

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

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

what is 1400?

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

Nice Post!! Really helpful.

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?

waiting for your reply

How to find out this value? – explain

Oxygen requirement =2734 kg/day

Hence, Air Requirement =11790 kg/day

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

Plant capacity

1400 assuming plant capacity

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

Nice information sir.thanks

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

Sir what is 250 in this calculation

250 is mg/l of effluent BOD (assume)

Pls sir explain this calculation in detail

how to calculate 350mg/d o2

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

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

Does the submergence SOTE vary with the depth ?

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

How come oxygen required-2734 kg/d,

How much O2 required for Per kg of BOD.

Plz elaborate.

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.

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

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