What is typically the first step in the treatment process of sewage in a septic system?

The first step in the treatment process of sewage in a septic system is the separation of solids and liquids. This initial stage is crucial because it allows for the efficient breakdown of organic matter and the effective treatment of wastewater.

In a septic tank, when sewage enters, gravity causes the heavier solids to settle at the bottom, forming sludge, while lighter materials like fats, oils, and grease float to the surface, forming a scum layer. This separation not only helps in managing the waste but also prepares the liquid effluent for further treatment processes, such as biological treatment or filtration, that occur later in the system.

Recognizing this foundational process is key to understanding how a septic system operates as a whole. The other steps mentioned, such as filtration of impurities, dosing of effluent, and disinfection of treated effluent, occur later in the treatment cycle and rely on the initial separation to function effectively.