Oxygen demand

Oxygen Demand is a term used in Environmental Science and Water Quality to describe the amount of oxygen required by organisms in a body of water to carry out their life processes. It is a critical factor in the health of aquatic ecosystems, as a high oxygen demand can lead to oxygen depletion, which can harm or kill aquatic organisms.

Biological Oxygen Demand

Biological Oxygen Demand (BOD) is a measure of the amount of oxygen required by bacteria and other microorganisms to decompose organic matter in water. It is a key indicator of the organic pollution of water, with higher BOD values indicating greater pollution. BOD is typically measured over a five-day period (BOD5), though longer periods can be used for more accurate results.

Chemical Oxygen Demand

Chemical Oxygen Demand (COD) is a measure of the total amount of oxygen required to oxidize all organic and inorganic matter in water, including substances that are not easily biodegradable. COD is a useful measure of water quality, as it can provide a quick estimate of BOD. However, it can overestimate the amount of oxygen demand due to the inclusion of inorganic matter.

Oxygen Demand and Water Quality

The level of oxygen demand in a body of water is a key factor in its overall quality. High levels of oxygen demand can lead to oxygen depletion or hypoxia, which can harm or kill aquatic organisms. This can lead to a decrease in biodiversity, as well as economic impacts on industries such as fishing and tourism.

See Also

• Water Quality
• Biological Oxygen Demand
• Chemical Oxygen Demand
• Oxygen Depletion
• Hypoxia (environmental)