# Required air to aeration tank - calculation ?

I want to determine if the blowers at a wastewater treatment plant is supplyinh enough air to the aeration tank. that parameters i have is flow rate, BOD5 influent and effluent, tank dimension. What equation can i use to determine the oxygen requirement? also, if the tank dimesion is absent is there an alternative equation that i can use to determine the oxygen requirement? and finally, how do i then convert the oxygen requirement which would be in power to cubic feet per minute? thank you so much for your help.

Shams

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### 1.

Since you know the BOD5 you know that is the Oxygen demand (in milli grams) per liter of effluent. All you need is to multiply the BOD5 value with the daily flow in liters to get the Oxygen demand (over five days) in milligrams.
Now the ultimate BOD is 1.67 times the BOD5. For simple and thumb rule calculation, multiply your above answer with 1.7 to get the Oxygen demand in millgrams.
Divide this by 1000 to get the demand in grams. Further divide this by 32 to get the molecular volume (32 grams of Oxygen occupy 22.4 liters), so multiply by 22.4 to get the daily requirement in liters.
Further multiply by 0.035 to get the daily amount in cubic feet. I am quite certain I do not need to guide you further to get your requirement in minutes; however you may divide this by "24x60" to get you cfm value.
This is a very simplistic solution. There are several other factors that need to be factored in such as temperature, pressure (atmospheric and hydraulic), etc.

Keshav Agarwal
sales@biotechservices.biz

### 2. Reg air required for aeration

Sir,

Please could you tell us a simply equation.

### 3. air requirement

I want to know why different amount of air is required for equalisation tank, SAFF tank and sludge holding tank? I also want to know how they are to be calculated?

### 4. Questions on aeration tank maintenance and troubleshooting

Sir,

I design aeration tanks in various capacity (20kld ,200kld ,2000kld,20000kld ,2002000kld). What formula and equations are used for design? Also, please tell me how to trouble shoot and maintain the aeration tank?

### 5. Need formula to calculate blower capacity for treatment plant

What is the simplest formula in calculating a blower capacity to use for a treatment plant of about 400 people?