Practice Test: Question Set - 15
1. Ventilating shafts are provided to a sewer line at every
- (A) 100 m
- (B) 150 m
- (C) 200 m
- (D) 300 m
2. Boussinesq's equation for ascertaining unit pressure at a depth ‘H’ on sewers due to traffic loads, is
- (A) pt = 3H3p/2πZ5
- (B) pt = 2H3p/3πZ5
- (C) pt = 3H3p/2Z5
- (D) pt = 2πH3p/3Z5
3. The most efficient cross section of sewers in a separate sewerage system is
- (A) Parabolic
- (B) Circular
- (C) Rectangular
- (D) New
egged
4. If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is
- (A) 2 hours
- (B) 3 hours
- (C) 4 hours
- (D) 5 hours
5. For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed
- (A) 1.5
- (B) 2.0
- (C) 2.5
- (D) 3.0
6. The settlement of a particle in sedimentation tank, is affected by
- (A) Velocity
of flow
- (B) Viscosity
of water
- (C) Size and
shape of solid
- (D) All the
above
7. If the pH value of sewage is 7
- (A) It is acidic
- (B) It is
alkaline
- (C) It is
neutral
- (D) None of
these
8. A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is
- (A) 0.30 m/sec
- (B) 0.35 m/sec
- (C) 0.40 m/sec
- (D) 0.45 m/sec
9. The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is
- (A) 5 m
- (B) 5.5 m
- (C) 6.5 m
- (D) 7 m
10. The sewer which collects the discharge from a collecting system and delivers it to a treatment plant, is known
- (A) House sewer
- (B) Lateral
sewer
- (C) Branch sewer
- (D) Sewer
outfall
11. For non-scouring velocity 5 m/sec, the type of sewers generally preferred to, is
- (A) Cast iron
sewers
- (B) Cement
concrete sewers
- (C) Glazed
bricks sewers
- (D) Stone ware
sewers
12. Pick up the correct statement from the following:
- (A) The boning
rod is used for checking the levels of the sewer inverts
- (B) Manhole
covers are made circular for the convenience of the cleaning staff
- (C) A manhole is
classified as shallow manhole if its depth is less than 0.9 m
- (D) All the
above
13. The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.25 m, is
- (A) 1.5
- (B) 2.0
- (C) 3.0
- (D) 4.0
14. The most dangerous pollutant in vehicular emissions is
- (A) CO
- (B) SO2
- (C) CO2
- (D) O3
15. Large diameter sewers subjected to external pressure alone, are reinforced
- (A) Near the
inner surface of the pipe
- (B) Near the
outer surface of the pipe
- (C) Both (a) and
(b)
- (D) With
elliptical cage
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