Biochemical Oxygen Demand or Biological Oxygen Demand, is a measurement of the amount of dissolved oxygen (DO) that is used by aerobic microorganisms when the decomposing organic matter in water. Biochemical Oxygen Demand is an important water quality parameter because it provides an index to assess the effect discharged wastewater will have in the receiving environment. The higher the BOD value, the greater the amount of organic matter or “food” available for oxygen-consuming bacteria.