1. The spacing of bars for perforations in coarse screens used for the treatment of sewage, is
Correct : D. 50 mm
2. The pH value of fresh sewage is usually
Correct : B. More than 7
3. The maximum depth of sedimentation tanks, is kept
Correct : A. 3 m
4. Lead caulked joints are used for laying
Correct : B. Earthenware pipes
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
Correct : C. D' = 0.84 D
6. The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewer
may be
Correct : D. > 1.5 m
7. The quantity of liquid waste which flows in sewers during the period of rainfall, is known
Correct : C. Storm sewage
8. Nitrogen cycle of sewage, is
Correct : A. Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
9. Depletion of ozone layer in the outer atmosphere may cause
Correct : B. Skin cancer
10. The minimum diameter of a sewer is kept
Correct : B. 15 cm
11. Which one of the following gases is most significant as air pollutant?
Correct : D. Sulphur-dioxide
12. Hazen's formula VS = 418 (GS - Gw)d [(3T + 70)/100] is used for the settlement velocity of the
particles of diameter
Correct : D. Greater than 0.1 mm
13. For sewers, inverted siphon is provided for
Correct : C. Three pipes
14. For large sewers, maximum distance between manholes may be
Correct : D. 300 m
15. In sewers designed with self cleansing velocity,
Correct : D. Neither silting nor scouring occurs at the bottom
16. The value of Chezy's constant C = 157.6/(1.81 + K/ 𝒓 ) is used in
Correct : B. Bazin's formula
17. Pathogens (or pathogenic bacteria’s) in water may cause
Correct : D. All the above
18. The rate of accumulation of sludge per person per year, is
Correct : C. 20 litres
19. The screens are fixed
Correct : C. At an angle 30° to 60° to the direction of flow
20. In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient,
Correct : B. Is doubled
21. In detritus tanks
Correct : D. All the above
22. The flow velocity in detritus tanks is
Correct : B. 0.09 m/sec
23. If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circular
section, is
Correct : D. 1095 mm
24. A nuisance is experienced in diluting water if dilution factor is less than
Correct : D. 20
25. A manhole is generally provided at each
Correct : D. All the above
26. The asbestos cement pipes are generally laid
Correct : B. Vertically
27. The design period in years for pumping plants, is
Correct : D. 5 to 10
28. Design period of 40 to 50 years is adopted for
Correct : D. All the above
29. In very first stage of decomposition of the organic matter in sewage
Correct : D. Ammonia is formed
30. In a city the ratio of the drainage to sewage is 20, the percentage discharge passing through
nonmonsoon periods, is
Correct : D. 20
31. The self-cleansing velocity of water flowing through pipe lines, is
Correct : A. 2 metres/sec
32. In case of sewer lines
Correct : D. All the above
33. The normal values of over flow rates for secondary sedimentation tanks, ranges between
Correct : A. 25,000 to 35,000 litres/sqm/day
34. A manhole is classified as shallow if its depth is between
Correct : C. 0.7 to 0.9 m
35. The first stage of neutral process of sludge digestion, is
Correct : A. Acid fermentation
36. The formula V = (1/n) r2/3 𝒔 used for determining flow velocities in sewers is known as,
Correct : D. Manning's formula
37. In sewers the highest non-scouring velocity is achieved in
Correct : A. Glazed bricks sewers
38. When the reduced level of the water source is higher than the reduced level of the consumer's
place, water is generally supplied
Correct : B. By gravitational system
39. Surcharge storage zone of a reservoir, is
Correct : C. Above useful storage
40. In pressure supply mains, water hammer pressure is reduced by providing
Correct : C. Pressure relief valves
41. Specific capacity or yield of wells, is generally expressed, as
Correct : D. m 3 /hour/m2 /m
42. Turbidity of raw water is a measure of
Correct : A. Suspended solids
43. If the chosen diameter of a pipe, is less than the economical diameter
Correct : D. All the above
44. While determining the yield of open wells by the pumping test
Correct : D. Maximum safe yield of an open well, is expected at critical depression head
45. The process of passing water through beds of granular materials, is called
Correct : C. Filtration
46. For the prediction of future population of a city, the factor to be considered, is
Correct : D. All the above
47. Mathamoglobinemia or blue baby disease is caused due to
Correct : C. Nitrates
48. To control the growth of algae in reservoirs, the compound which is used, is
Correct : B. Copper sulphate
49. A pressure conduit laid underground, may not be subjected to
Correct : C. Longitudinal temperature stress
50. The bacterias which require free oxygen for their survival, are called
Correct : A. Aerobic bacterias
51. Gravity conduits are generally in the form of
Correct : D. All the above
52. The bed slope in slow sand filters, is generally kept
Correct : C. 1 in 100
53. Perched aquifers are generally found
Correct : B. Below the surface of the ground but above water table
54. Pick up the incorrect statement from the following:
Correct : D. Lower value of pH gives alkaline solution
55. Mostly used coagulant, is
Correct : B. Alum
56. A centrifugal pump is required to be primed before starting if it is located
Correct : A. At higher level than water level of reservoir
57. Normal values of overflow rate for plain sedimentation tank, is
Correct : B. 500 to 750 litres/hr/m2
58. 'Shrouding' is essentially provided in
Correct : C. Slotted type well
59. The maximum permissible hardness for public supplies is
Correct : C. 115 mg/litre
60. The chlorine supply cylinders are generally kept at 38°C to 40°C to prevent
Correct : A. Conversion into crystals
61. For calculation of economical diameter D of a pipe in metres for a discharge Q to be pumped in
cumecs, Lea suggested the empirical formula
Correct : B. D = 1.22 𝑄
62. An earth formation which, although porous and capable of absorbing water does not provide an
appreciable supply to wells, is known as
Correct : B. Aquiclude
63. Property of earth to allow water to pass through it, is known as
Correct : B. Porosity
64. If G is the specific gravity of particles of diameter d, the velocity of settlement V in still water at
T°C, according to Stoke's law, is
Correct : A. V = 418 (G - 1) d² [(3T + 70)/100]
65. Distribution mains of any water supply, is normally designed for its average daily requirement
Correct : D. 225 %
66. Maximum threshold number permitted for indicating the odour of public water supplies, is
Correct : C. 3
67. The rate of silting in a reservoir
Correct : D. is more in the beginning and reduces in the end
68. Corrosion of well pipes may not be reduced by
Correct : D. Using screens having larger area of openings
69. Recuperation test is carried out to determine
Correct : C. Yield of well
70. Pick up the incorrect statement from the following. The underground sources of water, is from
Correct : D. Storage reservoirs
71. Most important method for calculating discharge for planning a water supply project, is
Correct : A. Velocity area method
72. In a rapid sand filter, air binding is caused due to excessive
Correct : A. Negative pressure
73. One degree of hardness of water means a content of salts of
Correct : C. 14.25 mg/litre
74. The U.C. (uniformity coefficient) D60/D10 for the best filter media sand should be
Correct : A. 2
75. Manholes are less common in
Correct : A. Cast iron pipes
76. For determining the velocity of flow of underground water, the most commonly used
nonempirical formula is
Correct : A. Darcy's formula
77. The most commonly used chemical for de-chlorination of water, is
Correct : C. Sodium sulphite
78. To remove very fine suspended particles from water, the method adopted is
Correct : D. Filtration
79. Sunlight
Correct : B. Impedes growth of algae
80. The detention period for plain sedimentation water tanks, is usually
Correct : D. 24 to 36 hours
81. Air valves are generally provided in pressure pipes of water supply
Correct : B. At summits
82. The gaseous form of chlorine gets converted into liquid form when subjected to a pressure of
Correct : C. 7 kg/cm2
83. Flow through period, in sedimentation tanks, is
Correct : C. Less than detention period
84. The maximum hourly consumption, is generally taken as
Correct : D. 150 %
85. Hardness of water can be removed by boiling if it is due to
Correct : A. Calcium bicarbonates
86. Hardness of water is caused by
Correct : C. Presence of bicarbonates, sulphates or chlorides of calcium and magnesium
87. The average domestic consumption under normal conditions in an Indian city per day per
person, is
Correct : D. 135 litres
88. If d is the diameter of the pipe, p is the total internal pressure, f is the permissible tensile stress
and n is the effective of the joint, the thickness t of metal pipe, is
Correct : B. (1/n) (pd/2f)
89. Generally, first portion of a logistic curve for the population growth of a developing city,
represents the growth of
Correct : A. Increasing
90. A pressure conduit carrying water beneath a stream or a canal, is known as
Correct : D. All the above
91. Most satisfactory formula for an estimate of fire demand Q for a city of population P in
thousands for Indian conditions, is
Correct : C. Q = 3180 𝑃
92. Permanent hardness of water can be removed by
Correct : D. Zeolite process
93. The maximum depth of sedimentation tanks is limited to
Correct : D. 6 m
94. Pick up the incorrect statement from the following. Intake of water supply should
Correct : C. Be located downstream of waste water disposal point
95. The fire demand of a city may be worked out by
Correct : D. All the above
96. The formula HL = n²V²L/R4/3 for the head loss in conduits is generally known as
Correct : B. Manning's formula
97. The joint used for joining the plain ends of cast iron pipes, is
Correct : C. Dresser coupling joint
98. Disinfection of water with ozone is not good because
Correct : D. It is more efficient than chlorine in killing bacterias
99. The prescribed hardness limit of potable water ranges between
Correct : B. 75 to 115 P.P.M.
100. While designing a water supply of an industrial township, industrial and commercial water
demand of total supply, is assumed