Question

In which type of filtration problem, layers of gravel are displaced?

(a) Clogging

(b) Air binding

(c) Sand incrustation

(d) Sand leakage

I got this question by my school teacher while I was bunking the class.

My question is based upon Problems in Filter Operation topic in portion Filtration of Environmental Engineering

Answer 1

Correct option is (d) Sand leakage

To elaborate: During Sand leakage, layers of gravel are displaced during back-washing. This can be minimized by proper proportioning of sand and gravel layers.