What is the purpose of a septic tank?

The purpose of a septic tank is to separate solids from liquids within the wastewater that comes from a household. When wastewater flows into the septic tank, it is typically comprised of a mixture of solids, liquids, and various organic materials. The septic tank functions through a process of settling, wherein the heavier solids sink to the bottom, forming a sludge layer, while lighter materials such as oils and grease float to the top, forming a scum layer. This separation allows for the liquid portion of the wastewater to flow out into the drain field for further treatment in the soil.

Other functions, such as filtration of chemicals from wastewater or increasing water pressure in pipes, do not accurately describe the primary role of a septic tank. Additionally, while irrigation may involve the utilization of water, this is not a function of a septic system. The key purpose remains the effective separation of solids and liquids, facilitating the proper treatment of wastewater in an environmentally responsible manner.