Which of the following describes a feature of a septic tank?

The correct response highlights that a septic tank is specifically engineered to promote the settling and digestion of organic matter found in wastewater. Inside the tank, solid waste settles at the bottom, forming sludge, while lighter materials, such as fats and oils, float to the top, creating scum. The design of the septic tank facilitates anaerobic digestion, where bacteria break down this organic matter over time. This process is crucial for reducing the volume of waste, preparing it for further treatment or absorption into the surrounding soil through a drain field.

The other options do not accurately describe the functions or characteristics of a septic tank. A septic tank does not aerate sewage naturally; its main function is anaerobic rather than aerobic. It is not connected to public sewer systems, as septic systems are standalone solutions used in areas without centralized sewer services. Additionally, septic tanks are not used for storing rainwater; their primary purpose is to treat and manage wastewater from homes or buildings. Understanding these functions reinforces the critical role septic tanks play in effective wastewater management in diverse settings.