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url: https://www.eurocovers.eu/glossary/bod
term: BOD (biochemical oxygen demand)
definition: A measure of the oxygen consumed by microbial decomposition of organic matter in water over a defined period (typically 5 days, BOD5). A primary wastewater compliance parameter.
updated: 2026-05-25
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# BOD (biochemical oxygen demand)

A measure of the oxygen consumed by microbial decomposition of organic matter in water over a defined period (typically 5 days, BOD5). A primary wastewater compliance parameter.

**BOD** (biochemical oxygen demand) measures the oxygen consumed by microorganisms decomposing
organic matter in a water sample over a defined period — typically 5 days, expressed as BOD5. It
is a primary wastewater compliance parameter under the EU Urban Waste Water Treatment Directive
and is used to size aeration capacity, characterise inflows, and demonstrate treatment
effectiveness. High BOD water bodies benefit from cover deployment for odor and emission reduction.