Practice Test: Question Set - 03
1. The sewer that unloads the sewage at the point of treatment is called
- (A) Main sewer
- (B) Outfall
sewer
- (C) Branch sewer
- (D) House sewer
2. During preliminary treatment of a sewage
- (A) Oil and
grease are removed from skimming tanks
- (B) Floating
materials are removed by screening
- (C) Girt and
sand are removed by girt chambers
- (D) All the
above
3. For a grit chamber, if the recommended velocity of flow is 0.2 m/sec and detention period is 2 minutes, the length of the tank, is
- (A) 16 m
- (B) 20 m
- (C) 24 m
- (D) 30 m
4. Dry weather flow is:
- (A) Average
daily rate of flow
- (B) Average
monthly rate of flow
- (C) Average
annual rate of flow
- (D) Water supply
allowance per capita
5. Pick up the incorrect statement from the following:
- (A) The mixture
of water and waste products, is called sewage
- (B) The treated
sewage effluents, are generally used for irrigating the crops
- (C) The process
of collecting, treating and disposing off the sewage, is called sewerage
- (D) The old
convergence system was definitely better than water carried sewerage system
6. Pick up the correct statement from the following:
- (A) The maximum
rate of storm runoff is called peak drainage discharge
- (B) Rational
method of estimating peak run off, may be used precisely for areas less than 50
hectares
- (C) The
period after which the entire area starts contributing to the runoff, is called
the time of concentration
- (D) All the
above
7. If q is the average sewage flow from a city of population P, the maximum sewage flow
- (A) Q = [(4 + √P)/(18 + √P)] q
- (B) Q = [(18 + P)/(4 + √P)] q
- (C) Q = [(18 + √P)/(4 + √P)] q
- (D) Q = [(5 + √P)/((15 + √P)] q
8. ¾th or ¼th extra space is left in sewer pipes at maximum discharge for
- (A) Low
estimates of the average and maximum flows
- (B) Large scale
infiltration of storm water
- (C) Unexpected
increase in population
- (D) All the
above
9. If the flame of a miner's safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains
- (A) Hydrogen
sulphide
- (B) Carbon
dioxide
- (C) Methane
- (D) Oxygen
10. Hydraulic mean radius is
- (A) Mean
radius of sewer
- (B) Difference
in heads between two points in circular pipes
- (C) Mean of
radii in a pipe line of varying cross-sections
- (D) Cross-sectional
area/wetted perimeter
11. If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is
- (A) πD/2
- (B) πD/4
- (C) πD/3
- (D) πD
12. Pick up the correct statement from the following:
- (A) Anaerobic
bacteria flourish in the absence of oxygen
- (B) Aerobic
bacteria flourish in the presence of oxygen
- (C) Facultative
bacteria flourish with or without oxygen
- (D) All
the above
13. The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.075 cumec for a total lift of 12 m, is
- (A) 10
- (B) 15
- (C) 20
- (D) 25
14. Aerobic bacterias
- (A) Flourish in
the presence of free oxygen
- (B) Consume
organic matter as their food
- (C) Oxidize
organic matter in sewage
- (D) All the
above
15. At the junction of sewers
- (A) Top of
smaller sewer is kept lower
- (B) Top of
larger sewer is kept lower
- (C) Tops of both
the sewers are at the same level
- (D) None of
these
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