What component in a septic system is specifically designed for the settlement of solids?

The component in a septic system specifically designed for the settlement of solids is the septic tank. In a septic tank, the wastewater from the household is held for a period of time to allow solids to settle at the bottom, forming sludge, while lighter materials, such as fats and oils, rise to the top, forming scum. This process is crucial for effective wastewater treatment, as it separates solids from the liquid effluent, which can then flow to the drain field for further treatment in the soil.

While the sedimentation chamber is also intended to facilitate the separation of solids from liquids, in the context of traditional septic system design, the septic tank is the primary component responsible for this function. The grease chamber and aeration chamber serve different roles—grease chambers are used to capture and separate fats, and aeration chambers are employed to provide oxygen for bacterial processes, which do not pertain directly to sedimentation. Hence, the septic tank is correctly identified as the core component where the settlement of solids occurs.