Question

Which of the following statement is correct?

(a) Ignition loss of filter should not exceed 3%

(b) Wearing loss of filter sand should not exceed 5%

(c) The range of CU for the slow sand filter is 3-5

(d) The range of CU for the rapid sand filter is 3-5

The question was posed to me in semester exam.

This interesting question is from Filter Media in division Filtration of Environmental Engineering

Answer 1

Right choice is (c) The range of CU for the slow sand filter is 3-5

The best explanation: The ignition loss of filter should not exceed 0.7%, wearing loss of filter sand should not exceed 3%, range of CU for the slow sand filter is 3-5 and  for the rapid sand filter is between 1.3 and 1.7.