Biochemical oxygen demand (BOD)
- Slovak term: Slovenský termín
- 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.
Explanation
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).
Example
“The suspended solids load in sullage is lower than in wastes from toilets, but it contains more grease and is generally at a higher temperature. Kitchen wastes have a higher suspended solids content, a higher biochemical oxygen demand, and a higher nitrate concentration than other sullage.”
References
- WHO (2006) Guidelines for the safe use of wastewater, excreta and greywater
- WHO (1992) A guide to the development of on-site sanitation
- Silva, 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
Links
- WHO — The Health and Environment Lexicon
- [UNEP, WHO (1996) Water quality monitoring: a practical guide to the design and]
- [implementation of freshwater quality studies and monitoring programmes]
