What device is a circular grinder designed to grind the solids coming through the screen into pieces about 0.3 cm or smaller?

• A. Headworks
• B. Comminutor
• C. Composite sample
• D. Detritus

Answer: (B)

A comminutor is the device described. It’s a circular grinder placed at the intake area to macerate solids that pass through the screen, grinding them into small pieces—about 0.3 cm (3 mm) or smaller. This reduces the size of debris before it reaches pumps and further treatment stages, helping prevent clogs, wear, and blockages downstream. The circular grinder uses rotating blades or teeth to chop and shear solids as they flow through, so the material exiting the grinder is much finer and easier to handle.

Headworks refers to the upstream facilities where screens and grit removal happen, not the grinding device itself. Detritus is the term for the solids in the flow, not a piece of equipment. A composite sample is a representative sample collected for analysis, not a grinder.