Question

What is the permissible negative head loss of a rapid sand filter?

(a) 0.2-1m

(b) 0.1-0.5m

(c) 0.5-2m

(d) 0.8-1.2m

I had been asked this question in homework.

This intriguing question comes from Problems in Filter Operation in portion Filtration of Environmental Engineering

Answer 1

Right choice is (d) 0.8-1.2m

The explanation is: The permissible negative head loss of a rapid sand filter is 0.8-1.2m. When the permissible limits are reached, the filter run is terminated and the filter is back washed.