What does septic tank primarily serve?

The primary function of a septic tank is to serve as a sewage disposal system for a single establishment, such as a home or a small business. Septic tanks are designed to treat and manage the wastewater generated from residential facilities. They work by allowing solids to settle at the bottom of the tank, where they undergo anaerobic digestion, while the liquid effluent is discharged into a drain field for further treatment and absorption into the soil.

This setup is essential in areas where municipal sewer systems are not available. Septic systems are tailored to the needs of individual households, making option C the most suitable description of their function.

In contrast, other options describe systems that are not aligned with the purpose of a septic tank. A community waste treatment system generally refers to larger-scale systems designed to serve multiple households or an entire neighborhood. Similarly, industrial waste management systems are designed for the disposal and treatment of waste from industrial processes and are not applicable to the residential context of a septic tank. Additionally, a public restroom facility employs sanitation methods that might include sophisticated plumbing systems or connection to city sewer systems, rather than relying on the independent functioning of a septic tank.