On-Site Sewage Facilities Installer II Practice Exam 2025 – Complete Test Prep

In a conventional septic system, the primary components are indeed the septic tank and the drain field. The septic tank serves as the initial treatment area where solids settle at the bottom, creating a sludge layer, while lighter materials like fats and greases float to the top, forming a scum layer. This separation and partial treatment process allows the liquid effluent that escapes from the septic tank to flow into the drain field.

The drain field is essential for the further treatment and dispersal of the effluent into the soil, where natural microbial processes continue to break down remaining contaminants. This combination of the septic tank and drain field forms a complete system that effectively manages wastewater through physical and biological processes.

While other options contain components related to wastewater treatment, they do not accurately represent the primary components of a conventional septic system. Treatment plants, aerobic treatment units, or leaching fields may be part of other systems or variations but do not define what is fundamental to a standard conventional septic system. Therefore, identifying the septic tank and drain field as the primary components is key to understanding how conventional septic systems operate effectively in managing on-site sewage disposal.