What is a water treatment process called where solid particles settle out in a large clarifier or sedimentation basin?

The water treatment process where solid particles settle out in a large clarifier or sedimentation basin is known as sedimentation. This process is critical in the treatment of water as it allows heavier particles, such as sand, silt, and other solid contaminants, to settle to the bottom of the basin due to gravity.

During sedimentation, water is typically held in a sedimentation tank for a specific period, allowing the solids to drop out of the water column, resulting in clearer water at the top. This process is fundamental to the overall water treatment system as it reduces the load on subsequent treatment processes, such as filtration, and improves water quality before further purification steps are taken.

In contrast, filtration involves passing water through a filter medium to remove smaller particles, flotation utilizes air bubbles to lift solid particles to the surface, and aeration introduces air into the water to remove volatile compounds or oxidize impurities. Each of these processes plays a unique role in water treatment, but sedimentation specifically focuses on the gravitational settling of solid materials.