Waste Water Engineering MCQ Practice - Set 01 - ObjectiveBooks

# Practice Test: Question Set - 01

1. For a continuous flow type of sedimentation tanks
(A) Width of the tank is normally kept about 6 m
(B) Length of the tank is normally kept 4 to 5 times the width
(C) Maximum horizontal flow velocity is limited to 0.3 m/minute
(D) All the above

2. The asbestos cement sewers are
(A) Light in weight
(B) Not structurally strong to bear large compressive stress
(C) Susceptible to corrosion by sulphuric acid
(D) All the above

3. For efficient working of a sewer, it must be ensured that
(A) Minimum velocity of 0.45 m/sec, is maintained at its minimum flow
(B) A maximum velocity of 0.90 m/sec, is maintained at its maximum flow
(C) Both (a) and (b)
(D) Neither (a) nor (b)

4. Pick up the correct statement from the following:
(A) The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge
(B) The sewer pipes of sizes greater than 0.4 m diameter are designed as running 2/3rd or 3/4th full at maximum discharge
(C) The minimum design velocity of sewer pipes is taken as 0.8 m/sec
(D) All the above

5. Pick up the correct statement from the following:
(A) Maximum daily flow = 2 times the average daily flow
(B) Maximum daily flow = ⅔ × average daily flow
(C) Sewers are designed for minimum permissible velocity at minimum flow
(D) All the above

6. Bottom openings 15 cm × 15 cm in the standing baffle wall are provided
(A) 15 cm c/c
(B) 22.5 cm c/c
(C) 30 cm c/c
(D) 50 cm c/c

7. The pressure exerted by
(A) The sewage when running full from inside, is called internal pressure
(B) The internal pressure if any, causes tensile stress in the pipe material
(C) Pressure sewers are designed to be safe in tension
(D) All the above

8. For drainage pipes in buildings the test applied before putting them to use, is
(A) Water test
(B) Smoke test
(C) Straightness test
(D) All the above

9. No treatment of the sewage is given if dilution factor is
(A) Less than 150
(B) Between 150 to 200
(C) Between 200 to 300
(D) More than 500

10. Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is?
(A) Centrifugal pump
(B) Pneumatic ejector
(C) Reciprocating pump
(D) None of these

11. Acid regression stage of sludge digestion at a temperature 21°C extends over a period of
(A) 15 days
(B) 30 days
(C) 60 days
(D) 90 days

12. Pick up the correct statement from the following:
(A) Small sewers are cleaned by flushing
(B) Medium sewers are cleaned by cane rodding
(C) Medium sewers may be cleaned by pills
(D) All the above

13. The coagulant which is generally not used for treating the sewage, is
(A) Alum
(B) Ferric chloride
(C) Ferric sulphate
(D) Chlorinated coppers

14. The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called
(A) A heap
(B) Plateau
(C) Windrow
(D) None of these

15. If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains
(A) Hydrogen sulphide
(B) Carbon dioxide
(C) Methane
(D) Oxygen

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