Georgia Residential Contractor Practice Exam

The correct answer indicates that the first compartment of a septic tank is designed to contain 2/3 of its total liquid capacity. This design is important for the effective treatment of wastewater. The first compartment serves as the primary settling chamber where the solid waste settles at the bottom, and grease and scum float to the surface. By having a larger volume in the first compartment, it allows for more solids to settle out, which is crucial for preventing clogging in the outlet pipe and ensuring that the effluent that moves to the second compartment (and subsequently to the drain field) is relatively clearer. The design reflects the need for adequate retention time in the septic tank, promoting anaerobic digestion of the organic matter and reducing the overall load on the drain field. Proper sizing of the compartments helps maintain the efficiency of the system and prolongs its lifespan. This design standard aligns with regulations and guidelines often established by environmental health agencies, ensuring effective treatment before wastewater is discharged into the surrounding soil.