The amount of oxygen (measured in mg/L) that is required for the decomposition of organic matter by single-cell organisms, under test conditions. It is used to measure the amount of organic contamination wastewater. BOD analyzers are highly effective in measuring the necessary improvements needed in wastewater process control and plant productivity. Since BOD is the standard measurement of wastewater toxicity in the United States, many operators are trained only with its understanding. Some of the drawbacks of this occurrence is that biochemical oxygen demand only takes into account the parts of organic carbon that is considered biologically degradable over certain amounts of time.