In an aerated grit chamber, how are settled solids typically removed?

• A. They are pumped from the top.
• B. They are gathered at the tank bottom by a rake mechanism and pumped.
• C. They are sucked through a central pipe.
• D. They are dissolved by bacteria.

Answer: (B)

In an aerated grit chamber, the heavy inorganic solids settle to the bottom while the aeration keeps lighter organics in suspension. The settled grit is then physically removed by a rake that travels along the tank floor, gathering the solids and directing them to a pump that moves them out of the chamber to a grit desludging or storage area. This bottom-collection method matches how grit behaves under flow and aeration, preventing buildup and protecting downstream equipment from abrasive solids. Pumping from the top wouldn’t reliably remove the settled grit, central suction isn’t how these chambers are designed, and bacteria don’t dissolve grit.