Question

What is the desirable value of mean velocity gradient in a flocculator?

(a) 20-50sec^-1

(b) 20-75sec^-1

(c) 50-100sec^-1

(d) 30-50sec^-1

This question was posed to me during an online interview.

This intriguing question comes from Flocculation and Clarification in division Sedimentation of Environmental Engineering

Answer 1

The correct answer is (b) 20-75sec^-1

To explain: The desirable value of mean velocity gradient (G) in a flocculator is 20-75sec^-1 and for ‘Gt’ is 2*10^4 to 6*10^4 where ‘Gt’ is the ratio of power induced rate of flow to displace mean induced rate of flow.