Wastewater Treatment Technology Tutorial

Sedimentation

Sedimentation simply entails the physical settling of matter, due to its density, buoyancy, and the force of gravity. Certain chemicals known as coagulants and flocculants are often used to expedite this process by encouraging aggregation of particles. Through sedimentation, the larger solids are removed in order to facilitate the efficiency of the following procedures and also to reduce the biological oxygen demand of the water.

The biological oxygen demand refers to the amount of oxygen required by the microbes within the wastewater to digest the matter that they are using for food.

By removing these solids early on, the efficiency of the microbial digestion at later stages is increased.