The quiescent settling of water without the aid of chemicals is known as?

The correct term for the process in which water settles without the addition of chemicals is plain sedimentation. This natural process involves allowing suspended particles within the water to settle to the bottom over time due to the force of gravity. It is an important step in water treatment, particularly in the removal of larger particles and some smaller ones, before further treatment processes.

In contrast, coagulation involves the addition of chemicals to water to destabilize suspended particles, which helps them clump together and settle more easily. Settling is a more general term that can describe various forms of sedimentation but does not specify the absence of chemicals. Flocculation refers specifically to the process where small particles aggregate into a larger floc through gentle mixing and the presence of chemical agents, which again contrasts with the natural process of plain sedimentation.