Biological oxygen demand (BOD)
About
·
Biological oxygen
demand (BOD) represents the amount of oxygen consumed by bacteria and other microorganisms
while they decompose organic matter under aerobic (oxygen is present)
conditions at a specified temperature.
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The common lake or
stream contains small amounts of oxygen in the form of dissolved oxygen
(DO). Dissolved oxygen is a crucial component of natural water
bodies, maintaining the aquatic life and quality aesthetic of streams and
lakes.
Significance
·
BOD is a measure
of the amount of oxygen required to remove waste organic matter from water in
the process of decomposition by aerobic bacteria (those bacteria that live only
in an environment containing oxygen).
·
BOD is an
important water quality parameter because it provides an index to assess the
effect discharged wastewater will have on the receiving environment.
·
The higher the BOD
value, the greater the amount of organic matter or “food” available for oxygen
consuming bacteria.
·
Depletion of
dissolve oxygen causes stress on aquatic organisms, making the environment
unsuitable for life. Further, dramatic depletion can lead to hypoxia or anoxic
environments.
·
BOD is also used
extensively for wastewater treatment, as decomposition of organic waste by
microorganisms is commonly used for treatment.
·
Determines the
amount of organic matter present in soils, sewages, sediment, garbage, sludge,
etc.
·
Biological oxygen
demand can be used as an indicator of the level of environmental pollution. For
instance, the higher the levels of organic matter (in polluted water bodies or
sewage), the greater the BOD.
|
Chemical
Oxygen Demand (COD) ·
COD is a method of estimating how
much oxygen would be depleted from a body of receiving water as a result of
bacterial action. ·
The difference between BOD and
COD is: COD or Chemical Oxygen Demand is the total measurement of all
chemicals (organics & in-organics) in the water, whereas, BOD is a
measure of, the amount of oxygen that require for the bacteria to degrade the
organic components present in water. |
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