Period of cleaning of slow sand filters is about________________?

Related Mcqs:

1. Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters. Reason R : The sand used in slow sand filters is finer than that in rapid sand filters. Select your answer based on the coding system given below?

   A. Both A and R are true and R is the correct explanation of A
   B. Both A and R are true but R is not the correct explanation of A
   C. A is true but R is false
   D. A is false but R is true

2. As compared to rapid sand filters, slow sand filters give______________?

   1) slower filtration rate
   2) higher filtration rate
   3) lesser efficiency in removal of bacteria
   4) higher efficiency in removal of bacteria
   The correct answer is?

   A. (1) and (2)
   B. (2) and (3)
   C. (1) and (4)
   D. (2) and (4)

3. The effective size of sand particles used in slow sand filters is_______________?

   A. 0.25 to 0.35 mm
   B. 0.35 to 0.60 mm
   C. 0.60 to 1.00 mm
   D. 1.00 to 1.80 mm

4. The rate of filtration in slow sand filters in million litres per day per hectare is about_____________?

   A. 50 to 60
   B. 100 to 150
   C. 500 to 600
   D. 1400 to 1500

5. The percentage of filtered water, which is used for backwashing in rapid sand filters, is about______________?

   A. 0.2 to 0.4
   B. 0.4 to 1.0
   C. 2 to 4
   D. 5 to 7

6. Air binding phenomena in rapid sand filters occur due to_________________?

   A. excessive negative head
   B. mud ball formation
   C. higher turbidity in the effluent
   D. low temperature

7. In water treatment, rapid gravity filters are adopted to remove_______________?

   A. dissolved organic substances
   B. dissolved solids and dissolved gases
   C. floating solids and dissolved inorganic solids
   D. bacteria and colloidal solids

8. The rate of Alteration of pressure filters is_________________?

   A. less than that of slow sand filters
   B. in between the filtration rate of slow sand filters and rapid sand filters
   C. greater than that of rapid sand filters
   D. equal to that of slow sand filters

9. The percentage of chlorine in fresh bleaching powder is about________________?

   A. 10 to 15
   B. 20 to 25
   C. 30 to 35
   D. 40 to 50

10. The means of access for inspection and cleaning of sewer line is known as_______________?

    A. inlet
    B. manhole
    C. drop manhole
    D. catch basin