Question

What is the effective size of Anthracite when used as a filter material?

(a) 0.1-0.2mm

(b) 0.2-0.4mm

(c) 0.4-0.6mm

(d) 0.7-0.75mm

I have been asked this question in homework.

My question comes from Rapid Sand Filter topic in section Filtration of Environmental Engineering

Answer 1

Correct choice is (d) 0.7-0.75mm

The explanation: The effective size of Anthracite when used as a filter material lies between 0.7-0.75mm and its uniformity coefficient is 1.75.