Which grit removal type causes flow to spiral so grit settles?

• A. Vortex
• B. Horizontal flow
• C. Aerated
• D. Bar screen

Answer: (A)

The key idea is using a swirling, vortex flow to separate grit from the wastewater by inertia and centrifugal forces. In a vortex grit removal system, wastewater enters in a way that makes it spin around, creating a circular flow. The rotation pushes the dense grit outward toward the outer wall and downward into a grit sump, so the grit settles out. Lighter materials and the clarified water stay in suspension and exit with the effluent. This swirl is what makes grit settle efficiently. The other options don’t produce that spiraling flow: horizontal flow lacks the swirl needed for centrifugal separation; an aerated chamber relies on air mixing rather than a stable vortex; a bar screen is a physical barrier, not a flow-induced settling method.