In gravity-flow to the leaching bed, effluent movement is driven by which factor?

In gravity-flow to the leaching bed, effluent movement is driven by which factor?

• A. Pumping pressure
• B. Volume of sewage entering the tank
• C. Air pressure
• D. Temperature difference

Answer: (B)

In gravity-flow systems, movement of effluent is driven by hydrostatic pressure from the liquid column in the septic tank. The higher the liquid level, the greater the pressure at the outlet, which pushes effluent toward the leaching bed. The volume entering the tank controls that head—the more sewage entering, the higher the head and the more flow to the bed. Pumping pressure isn’t involved in gravity flow, and air pressure or temperature differences don’t provide the driving force.

In gravity-flow systems, movement of effluent is driven by hydrostatic pressure from the liquid column in the septic tank. The higher the liquid level, the greater the pressure at the outlet, which pushes effluent toward the leaching bed. The volume entering the tank controls that head—the more sewage entering, the higher the head and the more flow to the bed. Pumping pressure isn’t involved in gravity flow, and air pressure or temperature differences don’t provide the driving force.