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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