The BOD determination is an empirical test that is widely used for measuring waste (loading to and from wastewater treatment plants),evaluating the organic removal efficiency of treatment processes, and assessing stream assimilative capacity. The BOD test measures: (1) the molecular oxygen consumed during a specific incubation period for the biochemical degradation of organic matter (CBOD); (2) oxygen used to oxidize inorganic material such as sulfide and ferrous iron; and (3) reduced forms of nitrogen (NBOD) with an inhibitor (trichloromethylpyridine). If an inhibiting chemical is not used, the oxygen demand measured is the sum of carbonaceous and nitrogenous demands, so-called total BOD or ultimate BOD.