Types of tests used to determine Biochemical oxygen demand(BOD)

1. Department Of Civil Engineering
University Of Engineering &
Technology Peshawar

2. Types of Tests Used to Determine BOD
There are different types of tests that can be used to determine Biochemical Oxygen Demand (BOD)
in water samples, depending on the laboratory's capabilities and the purpose of the analysis. Here are
some of the common tests used to determine BOD.
Dilution method
Respiro-metric method
Titrimetric method
Man metric method

3. Dilution Method
• This is the most commonly used method to determine BOD in water
samples.
• In this method, a series of dilutions of the sample is prepared and
incubated for a specified period, usually five days, at a constant
temperature of 20°C.
• The dissolved oxygen (DO) in the sample is measured at the beginning
and end of the incubation period, and the BOD is calculated based on the
difference in DO levels.

4. • This method measures the oxygen uptake rate of microorganisms in the
water sample by monitoring the changes in DO concentration in a closed
vessel containing the sample. The rate of oxygen uptake is used to
calculate the BOD of the sample.
Respiro-metric Method

5. Titrimetric Method
• In this method, the oxygen demand of the sample is determined by
measuring the amount of oxygen consumed by a chemical reagent, such as
potassium permanganate, that is added to the sample. The BOD is
calculated based on the amount of reagent consumed.

6. Mano-Metric Method
• This method involves measuring the pressure changes in a closed vessel
containing the water sample as microorganisms in the sample consume
oxygen during the incubation period. The pressure changes are used to
calculate the BOD.