1. Introduction The biochemical oxygen demand (BOD) test is a crucial environmental index to determine the relative
oxygen requirements of wastewaters, effluents and polluted waters. It measures the molecular oxygen utilized during a specified incubation period for the biochemical degradation of organic material (carbonaceous demand) and the oxygen used to oxidize inorganic material such as sulphides and ferrous ions. It can also be a measure of oxygen used to oxidize reduced forms of nitrogen (nitrogenous demand), unless their oxidation is prevented by an inhibitor. The conventional BOD test