NALT Full

A measure of the amount of a water body's dissolved oxygen supply that would be used up in completely oxidizing added inorganic oxidizable compounds-such as in the oxidation of ammonia to nitrate. Biological oxygen demand (BOD) tests can only measure the biodegradable fraction of the total potential dissolved oxygen consumption by added wastes; however, COD tests may be used to measure the oxygen demand created by toxic organic or inorganic compounds as well as by biodegradable substances. A standard COD test, therefore, can be used to evaluate many industrial type wastes not readily analyzed for water quality factors by the sewage-oriented BOD test.