Biochemical oxygen demand


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Terms & Synonyms

Official WHO Definition

The amount of oxygen that is required to biochemically convert organic matter into inert substances; an indirect measure of the amount of biodegradable organic matter present in the water or wastewater.See BOD

Other Definitions


Interpretations and Explanations

The biochemical oxygen demand (BOD) is an empirical test, in which standardised laboratory procedures are used to estimate the relative oxygen requirements of wastewaters, effluents and polluted waters. The BOD is used as an approximate measure of the amount of biochemically degradable organic matter present in a sample. BOD is usually measured in milligrams of oxygen per litre, mg/L. Standardised laboratory procedure determines BOD by measuring the amount of oxygen consumed after incubating the sample in the dark at a specified temperature for a specific period of time, usually five days. The oxygen consumption is determined from the difference between the dissolved oxygen concentrations in the sample before and after the incubation period.BOD is usually reported as an indicator of organic matter contamination. Some rivers and water courses in tropical environments, shows values such as 40 mg/l of BOD in nature (Nemerow, 1971). Typical values of BOD for domestic wastewater are between 200-500 mg/l and for industrial wastewater could rise values such as 10,000 to 22,000 mg/l for industrial efluent for production of alcohol elaborated from sugar cane (Silva e Mara, 1979).


WHO (2006) Guidelines for the safe use of wastewater, excreta and greywaterWHO (1992) A guide to the development of on-site sanitationSilva, A.S e Mara, D.D. (1979) Tratamentos Biológicos de Águas Residuarias: Lagoas de Estabilização, Rio de Janeiro, ABES. Nemerow, N. L. (1971) Liquid waste of industry: theories, practices and treatment, Syracuse University. Ed. Addison Wesley

UNEP, WHO (1996) Water quality monitoring: a practical guide to the design and implementation of freshwater quality studies and monitoring programmes

WHO Lexicon page (translations and examples)

See also

External Resources


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