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Biochemical Oxygen Demand and Other Organic Pollution Measures

Water Quality Control

  1. Neil F. Pasco,
  2. Joanne M. Hay

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.wq1514

Water Encyclopedia

Water Encyclopedia

How to Cite

Pasco, N. F. and Hay, J. M. 2005. Biochemical Oxygen Demand and Other Organic Pollution Measures. Water Encyclopedia. 2:37–41.

Author Information

  1. Lincoln Ventures, Ltd., Lincoln, New Zealand

Publication History

  1. Published Online: 15 JUL 2005


Biochemical oxygen demand (BOD) is the most important and widely used environmental index for monitoring organic pollutants in wastewater. The current international standard method is the five-day BOD assay (BOD5). The test measures the amount of dissolved oxygen required for the microbial oxidation of carbonaceous organic material under specified conditions. The test has its widest application in measuring waste loadings to treatment plants and in evaluating the BOD-removal efficiency of such treatment systems.

Practical difficulties exist associated with the BOD5 test, including sensitivity to temperature and oxygen concentration, impact of toxins, lack of stoichiometric validation, and the need to dilute samples. The test is labor intensive with variable results, but the major drawback continues to be the five-day measurement time.

For all its shortcomings and the availability of a number of related measurement techniques, the BOD5 assay remains the preferred test for reporting the oxygen requirements of wastewaters, effluents, and polluted waters, in part, because of its international regulatory status, but also because it uniquely simulates the microbial decomposition of organic wastes in the environment, thereby approximating the response of natural ecosystems.


  • biochemical oxygen demand;
  • BOD;
  • BOD5 test;
  • dissolved oxygen;
  • biodegradability;
  • water quality;
  • wastewater;
  • oxidation;
  • microorganisms;
  • glucose-glutamic acid standard;
  • OECD standard;
  • chemical oxygen demand;
  • total organic carbon;
  • rapid BOD sensors