What is BOD and How Is It measured?

Biochemical 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. The decay of organic matter in water is measured as biochemical or chemical oxygen demand.

How do you perform a BOD test?

The test for biochemical oxygen demand (BOD) is a bioassay procedure that measures the oxygen consumed by bacteria from the decomposition of organic matter (Sawyer and McCarty, 1978). The change in DO concentration is measured over a given period of time in water samples at a specified temperature.

What is the principle of BOD?

BOD is based on the principle that if sufficient oxygen is available, aerobic biological decomposition (i.e., stabilization of organic waste) by microorganisms will continue until all waste is consumed.

How do you calculate BOD of water?

BOD measurement requires taking two samples at each site. One is tested immediately for dissolved oxygen, and the second is incubated in the dark at 20 C for 5 days and then tested for the amount of dissolved oxygen remaining.

What is BOD and how is it determined?

Biochemical oxygen demand, or BOD, is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic biological organisms in a body of water to break down organic material present in a given water sample at certain temperature over a specific time period.

What is biochemical oxygen demand test?

Biochemical oxygen demand. The biochemical oxygen demand ( BOD ) test is an indirect measure of the biodegradable organic matter in an aqueous sample. The test is indirect because oxygen used by microbes as they degrade organic matter is measured, rather than the depletion of the organic materials themselves.

What does biochemical oxygen demand measure?

Biochemical oxygen demand or biological oxygen demand ( BOD ) is a measure of the amount of Dissolved Oxygen (DO) required by aerobic microorganisms to decompose organic matter present in a sample of water at a certain temperature over a studied period. BOD value is usually expressed in milligrams of oxygen per liter of water (mg/L).

How is BOD measured?

BOD can be measured by three different techniques – the Winkler method, by using a dissolved oxygen probe or manometrically. • The Winkler method is a titrimetric wet chemistry test that measures the amount of oxygen present based on conversion of oxygen to iodine.