Ultimate BOD Calculator

Solve for ultimate biochemical oxygen demand to measure the amount of oxygen used by bacteria to metabolize organic material in water.


How Ultimate BOD calculator works

The ultimate BOD is the amount of oxygen required to decompose all of the organic material after infinite time.

This is usually simply calculated by conducting the experiment over a 20thday period.

The BOD test measures the strength of the wastewater by measuring the amount of oxygen used by the bacteria as they stabilize the organic matter under controlled conditions of time and temperature.

Formula :

L = BODt(1-e-kt)


BODt 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 Problems:

The BOD5 of a wastewater is determined to be 150 mg/L. The k value is known to be 0.23 per day.What would be the ultimate BOD value?

a) Determine the ultimate BOD

L = BODt(1-e-kt)

L = 150(1-e-0.23×5)

L = 220 mg/L