Biochemical Oxygen Demand (BOD)
A measure of the amount of oxygen consumed by aerobic microorganisms to decompose organic matter in a water sample.
What is Biochemical Oxygen Demand (BOD)?
The amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
Key points
- Define Biochemical Oxygen Demand (BOD).
- Explain the significance of BOD in water quality assessment.
- Describe the principle behind the BOD test.
- Relate BOD levels to the presence of organic pollution and its impact on aquatic ecosystems.
Common exam trap
Confusing BOD with DO (Dissolved Oxygen).
Definitions
- Term
Biochemical Oxygen Demand (BOD)
- Meaning
The amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
- Term
Dissolved Oxygen (DO)
- Meaning
The amount of free oxygen dissolved in a water body, essential for the survival of aquatic organisms.
- Term
Aerobic Decomposition
- Meaning
The breakdown of organic matter by microorganisms in the presence of oxygen.
Learning objectives
Define Biochemical Oxygen Demand (BOD).
Explain the significance of BOD in water quality assessment.
Describe the principle behind the BOD test.
Relate BOD levels to the presence of organic pollution and its impact on aquatic ecosystems.
Prerequisites
Understanding of basic chemistry (oxygen, decomposition).
Knowledge of microorganisms (bacteria, aerobic respiration).
Concept of dissolved oxygen (DO) in water.
Common mistakes
Confusing BOD with DO (Dissolved Oxygen).
Assuming BOD directly measures all pollutants (it primarily measures biodegradable organic matter).
Not understanding the time and temperature dependency of the BOD test.
Overlooking the impact of non-biodegradable organic matter on BOD.
Keywords
BOD
Biochemical Oxygen Demand
Water Pollution
Dissolved Oxygen
Aerobic Respiration
Sewage Treatment
Eutrophication
Water Quality
Practice preview
A high BOD value in a water body typically indicates:…
easy
Which of the following is a unit commonly used to express BOD?…
easy
The BOD test is typically performed over a period of:…
medium