What is the primary definition of Settleable Solids?

Settleable solids refer to the solid particulate matter in a liquid that can be separated by the process of sedimentation, where the particles settle out of the liquid under the influence of gravity over time. The primary definition involves measuring the volume of these solids when they are allowed to settle in a controlled environment, such as in a graduated cylinder over a specified period. This measurement captures the amount of material that is dense enough to overcome the buoyancy of the liquid and aggregate at the bottom.

The process involves taking a sample of water, placing it in a container, and allowing it to remain undisturbed for a set period, after which the volume of solids that have settled out can be accurately measured. This is significant in water quality assessments and the design of wastewater treatment systems, as it helps in evaluating the effectiveness of sedimentation processes and the concentration of suspended solids.

In contrast, the remaining choices do not accurately encapsulate the definition of settleable solids. The first option describes suspended solids, which is the opposite of settleable solids since these do not settle. The third option involves a measurement of total solids but does not specifically relate to the settling process. The fourth refers to filtered solids, which implies a different separation mechanism unrelated to the settling phenomenon.