Which statement best describes the purpose of a septic tank?

Which statement best describes the purpose of a septic tank?

• A. To chlorinate wastewater
• B. To receive raw wastewater, separate solids from liquids, and discharge clarified liquid to the SAS.
• C. To store treated wastewater for reuse
• D. To heat wastewater

Answer: (B)

Septic tanks are the first stage of a typical on-site system. They receive raw wastewater from the building, allow solids to settle to the bottom (sludge) and greases to rise to the top (scum), and keep the liquid portion in the middle long enough for partial anaerobic digestion. The liquid that leaves the tank is a clearer effluent that goes on to the soil absorption system (SAS) for final treatment in the soil. This is exactly what the stated purpose describes: receiving raw wastewater, separating solids from liquids, and discharging clarified liquid to the SAS. It’s not about chlorinating wastewater, storing treated wastewater for reuse, or heating wastewater.

Septic tanks are the first stage of a typical on-site system. They receive raw wastewater from the building, allow solids to settle to the bottom (sludge) and greases to rise to the top (scum), and keep the liquid portion in the middle long enough for partial anaerobic digestion. The liquid that leaves the tank is a clearer effluent that goes on to the soil absorption system (SAS) for final treatment in the soil. This is exactly what the stated purpose describes: receiving raw wastewater, separating solids from liquids, and discharging clarified liquid to the SAS. It’s not about chlorinating wastewater, storing treated wastewater for reuse, or heating wastewater.