7. Glossary

Clarification; clarification

Clarification is the process of making clear a liquid containing suspended particles. In most cases, this involves decantation, a process by which particles settle in a large tank without agitation, producing clearer water on overflow. In some cases, filtration may also be used.

BOD (Biological Oxygen Demand)

Biochemical oxygen demand (BOD) is the quantity of oxygen required to oxidize (biodegradable) organic matter by biological means (bacteria). It is used to assess the biodegradable fraction of the carbonaceous pollutant load in wastewater. It is generally calculated after 5 days at 20°C and in the dark. This is referred to as BOD ₅ . European regulations impose a BOD ₅ discharge standard of...