 # Biochemical Oxygen Demand (BOD) Exertion Calculator

Solve for biochemical oxygen demand to measure the amount of oxygen used by bacteria to metabolize organic material in water. ## How BOD Exertion Equations calculator works

The BOD calculator gives a measure of the oxygen utilized by bacteria during the oxidation organic material contained in a waste water sample.

If you determine the BOD after 5 days, this is called the 5 day BOD (BOD5). If you determine the BOD after 20 days, this is called the 20 day BOD (BOD20). These are really BOD exerted values.

Formula :

yt = L(1 - e-k × t)

Where,

yt is amount of BOD exerted at time t in mg/L

L is ultimate BOD in mg/L

t is time in days

k is deoxygenation rate constant in days-1 or 1/days

Solved Examples :

The BODL of a sample is 120 mg/L. If 'k' for this sample is 0.28 day-1.How much of the BOD is exerted and how much remains after the following time intervals (a) 3 days , (b)5 days and (c) 10 days ?

(a) y3 = 120(1-e-0.28×3) = 68 mg/L

(a) y5 = 120(1-e-0.28×5) = 90 mg/L

(a) y10 = 120(1-e-0.28×10) = 113 mg/L 