Biological Oxygen Demand of Water

Biological Oxygen Demand of Water (BOD) is defined as the amount of oxygen required by bacteria while stabilizing decomposable organic matter under aerobic conditions. The results are commonly expressed in terms of weight of oxygen required per unit volume of the initial sample.

BOD represents the amount of organic matter in a water supply. Therefore, it increases when decaying plants, human or animal waste, and other organic compounds are added to water.

Higher BOD indicates more oxygen is required, which is less for oxygen-demanding species to feed on, and signifies lower water quality. Inversely, low BOD means less oxygen is being removed from water, so water is generally purer.

BOD is generally considered to be a useful way of expressing stream pollution loads and for comparing one set of conditions with another.

BOD determinations are made by measuring residual dissolved oxygen in a water sample or a diluted aliquot after an incubation period.

BOD test has little geochemical significance, but it is widely used to determine the strength of domestic and industrial wastes in terms of the oxygen that they will require if discharged into a natural water course.

End of Biological Oxygen Demand of Water

More about Dissolved Gases…
Chemical Oxygen Demand of Water
Carbon Dioxide in Water

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