<P> Biochemical Oxygen Demand (BOD, also called Biological Oxygen Demand) is the amount of dissolved oxygen needed (i.e. demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period . The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at 20 ° C and is often used as a surrogate of the degree of organic pollution of water . </P> <P> BOD can be used as a gauge of the effectiveness of wastewater treatment plants . It is listed as a conventional pollutant in the U.S. Clean Water Act . </P> <P> BOD is similar in function to chemical oxygen demand (COD), in that both measure the amount of organic compounds in water . However, COD is less specific, since it measures everything that can be chemically oxidized, rather than just levels of biodegradable organic matter . </P>

Biological oxygen demand (bod) is a standard criterion for