What does the Imhoff cone measure?

The Imhoff cone is specifically designed to measure settleable solids in wastewater. It is a clear, conical container that allows for the observation of solid materials as they settle to the bottom over time. The test begins by collecting a wastewater sample, and when placed in the cone, the solids that are capable of settling under gravity begin to accumulate.

The volume of the settled solids can be quantified after a specified settling period, typically 30 minutes. This measurement is critical as it helps in assessing the efficiency of sedimentation processes in wastewater treatment and indicates the portion of solids that can separate from the liquid phase under quiescent conditions.

While settled solids and suspended solids are concepts related to the measurement of solid particles in water, the Imhoff cone specifically quantifies the proportion of solids that settle out of a sample, as opposed to those remaining in suspension or those that do not settle easily, such as colloidal solids.