Q.1
The rainfall at any place may be determined by
  • Its intensity
  • Its direction
  • Its frequency
  • All the above
Q.2
Nitrogen cycle of sewage, is
  • Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
  • Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
  • Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
  • Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates
Q.3
Hydraulically equivalent, the relationship which holds good, is
  • D8/3 = 4 b8/3
  • D3/8 = 4 b3/8
  • D2/3 = 4 b2/3
  • D3/2 = 4 b3/2
Q.4
For design of sewers, percentage of sewage discharge is assumed
  • 65 to 70%
  • 70 to 75%
  • 75 to 80%
  • 85%
Q.5
If D is the diameter of a circular sewer and D’ is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is
  • D’ = 0.64 D
  • D’ = 0.74 D
  • D’ = 0.84 D
  • D’ = 0.94 D
Q.6
If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of
  • Degradation
  • Active decomposition
  • Recovery
  • Cleaner water
Q.7
The drainage area of a town ishectares. Itsarea is hard pavement ( K = 0.85), thearea is unpaved streets (K = 0.and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas asminutes and using the formula Ps = 900/(t +the maximum run off is
  • 0.10 cumec
  • 0.12 cumec
  • 0.15 cumec
  • 0.20 cumec
Q.8
The sewer which transports the sewage to the point of treatment, is called
  • House sewer
  • Out-fall sewer
  • Branch sewer
  • Main sewer
Q.9
The standard B.O.D. of water is taken for
  • 1 day
  • 2 days
  • 3 days
  • 5 days
Q.10
To prevent settling down of sewage both at the bottom and on the sides of a large sewer, self-cleaning velocity recommended for Indian conditions, is
  • 0.50 m/sec
  • 0.60 m/sec
  • 0.70 m/sec
  • 0.75 m/sec
Q.11
The quantity of liquid waste which flows in sewers during the period of rainfall, is known
  • Sanitary sewage
  • Industrial waste
  • Storm sewage
  • None of these
Q.12
In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is
  • Q/(B × D)
  • Q/(L × D)
  • Q/L
  • Q/(B × L)
Q.13
Maximum permissible velocity 1.5 m/sec, is adopted in drains
  • With beds of rocks and gravels
  • Lined with stones
  • Both and
  • Neither nor
Q.14
The maximum spacing of manholes specified by Indian standard in sewers upto 0.3 m diameter is
  • 20 m
  • 30 m
  • 45 m
  • 75 m
Q.15
If is the rugosity coefficient, is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula V = (1/n) r2/3 s1/2 evolved by
  • Chezy
  • Manning
  • Bazin
  • Kutter
Q.16
The value of Chezy’s constant C = 157.6/(1.+ K/ ) is used in
  • Chezy’s formula
  • Bazin’s formula
  • Kutter’s formula
  • Manning’s formula
Q.17
In trickling filter, B.O.D. is reduced to
  • 30 to 40%
  • 40 to 60%
  • 60 to 80%
  • 80 to 90%
Q.18
Drop manholes at the junctions of sewer lines, are provided if
  • Invert level of a branch sewer is more than 60 cm that of the main sewer
  • Sewer line runs along a main road
  • Ordinary manhole cannot be built
  • Two sewer lines intersect
Q.19
It is customary to design a sewer for D.W.F. on the basis of
  • Average demand
  • Twice the average demand
  • Thrice the average demand
  • Four times the average demand
Q.20
Dry weather flow is:
  • Average daily rate of flow
  • Average monthly rate of flow
  • Average annual rate of flow
  • Water supply allowance per capita
Q.21
The sewage treatment units in which anaerobic decomposition of organic matter is used, are called
  • Imhoff tanks
  • Trickling filters
  • Sludge sedimentation tanks
  • None of these
Q.22
The porosity of sediments in sewer pipes, is usually taken as
  • 0.010
  • 0.011
  • 0.012
  • 0.013
Q.23
In a grit chamber of a sewage treatment plant,
  • Flow velocity 0.15 m to 0.3 m/sec is kept
  • Depth of 0.9 m to 1.20 m is kept
  • One minute of detention period is kept
  • All the above
Q.24
A sewer pipe contains 1 mm sand particles of specific gravity 2.and 5 mm organic particles of specific gravity 1.the minimum velocity required for removing the sewerage, is
  • 0.30 m/sec
  • 0.35 m/sec
  • 0.40 m/sec
  • 0.45 m/sec
Q.25
The spacing of man holes along a straight portion of a sewer ism, the diameter of the sewer may be
  • 0.9 cm
  • 1.2 m
  • 1.5 m
  • > 1.5 m
Q.26

kg of sewage contains

  • 0.112 kg in suspension
  • 0.112 kg in solution
  • 0.225 kg in solution
  • 0.450 kg in suspension
  • both (a) and (c) of above.
Q.27

A cylindrical ejector having its height 2 m fills after everyminutes with a peak sewage discharge of 0.cumec. The diameter of the ejector chamber, is

  • 2.30 m
  • 2.40 m
  • 2.45 m
  • 2.50 m.
0 h : 0 m : 1 s