Question

The thickness of the base material of a rapid sand filter on which filter media are supported is __________

(a) 45-60cm

(b) 20-80cm

(c) 30-75cm

(d) 10-30cm

This question was posed to me during an interview for a job.

Query is from Rapid Sand Filter topic in portion Filtration of Environmental Engineering

Answer 1

Right choice is (a) 45-60cm

The best explanation: The base material of a rapid sand filter consists of 45-60 cm thick gravel bed which is laid in layers of 15 cm with a finer topmost layer (2-6mm) and coarser bottom layer (20-50mm).