2. The maximum permissible chlorine content for public supplies should be between
Correct : A. 0.1 to 0.2 ppm
3. Air vent pipe is not essentially required in a septic tank.
Correct : B. False
4. The pocess of excluding large sized particles from water with the help of screens is called filteration.
Correct : B. No
5. A pipe installed for ventilation purpose is called
Correct : C. vent pipe
6. The presence of calcium and magnesium chloride in water causes
Correct : C. hardness
7. In the process of screening, the screens should be inclined at an angle of
Correct : C. 45? to 60?
8. To prevent the formation of crystalline hydrates of 'Ice' of chlorine, the chlorine supply cylinders are kept at a temperature from
Correct : D. 38?C to 42?C
9. When chlorine is added to raw water at more than one point, the process is termed as break point chlorination.
Correct : B. Wrong
10. Manholes on sewer lines are provided for
Correct : A. periodic cleaning
11. The length of rectangular sedimentation tank should not be more than
Correct : C. four times
12. The most commonly used chemical for dechlorination of water is
Correct : D. all of these
13. The discharge from washing places is called sullage.
Correct : A. True
14. The portion of soil through which lateral movement of water takes place is called
Correct : C. zone of saturation
15. A septic tank is a
Correct : C. combination of sedimentation and digestion tank
16. Under steady low heads
Correct : B. centrifugal
17. The maximum permissible total solid content in water for domestic purposes should not exceed
Correct : C. 500 ppm
18. Cleaning of rapid sand filters is done by
Correct : B. back washing
19. The sand, used for filteration, should not loose weight more than
Correct : B. 5%
20. Bleaching powder is
Correct : D. hypo-chlorite of lime
21. The efficiency of sedimentation tank for a given discharge, can be increased by
Correct : C. increasing the surface area of tank
22. Absolute pure water is good for health.
Correct : B. Wrong
23. The most important source of water for public water supply is
Correct : D. sea
24. The most common cause of acidity in water is
Correct : C. carbon dioxide
25. Water is
Correct : B. harmful
26. The temporary hardness due to calcium bicarbonates can be removed by
Correct : A. boiling
27. Which of the following statement is correct?
Correct : C. In a ring system, there is one main supply pipe.
28. The minimum diameter of a manhole cover should be
Correct : B. 50 cm
29. An egg-shaped cross-section of a sewer
Correct : C. provides self cleaning velocity in dry weather
30. Garbage is a
Correct : A. dry waste
31. The human excreta is a
Correct : B. semi-liquid
32. The increase in population of a young and rapidly developing city is estimated by comparative method.
Correct : B. False
33. The lime soda process of water softening
Correct : D. all of these
34. Odours and tastes may result due to the prsence of
Correct : D. all of the above
35. The lower portion of a manhole is is known as
Correct : C. working chamber
36. Which of the following statement is wrong?
Correct : D. The initial cost of construction of water carriage system is very low.
37. Land disposal of sewage will be favourable where
Correct : A. the rivers run dry or have a small flow during summer
38. The amount of residual chlorine in treated water is determined by the
Correct : D. all of these
39. When in the pervious strata, the surface of water surrounding the well is at atmospheric pressure, the well is known as
Correct : A. gravity well
40. The natural outflow of sub-surface water at the surface is termed as spring.
Correct : A. Correct
41. When turbidity of water exceeds about 45 ppm, coagulation
Correct : A. should be
42. Manholes are, generally, located
Correct : D. all of these
43. The bacteria which require oxygen for their survival is known as
Correct : C. aerobic bacteria
44. The turbidity in water is caused due to
Correct : D. all of these
45. The process of removing excess chlorine from water is called
Correct : C. dechlorination
46. The coefficient of uniformity for slow sand filters is
Correct : C. 1.75
47. In a rapid sand filter, the filter head varies from
Correct : C. 2 to 4 m
48. For a city or town with roads of rectangular pattern, the type of layout used for the distribution of pipes is
Correct : D. grid iron system
49. The type of joint to be used in pipes depends upon the
Correct : D. all of these
50. Grit chambers are used to remove sand and other organic matter from sewage.
Correct : A. Agree
51. The water supply system means
Correct : B. the complete layout from the source of supply to the distribution
52. The process of dechlorination is followed by
Correct : C. super chlorination
53. Suspended impurities cause turbidity in water.
Correct : A. Yes
54. The horizontal tunnels constructed at shallow depths along the banks of a river to intercept the ground water table are called
Correct : B. infiltration galleries
55. Air binding means accumulation of
Correct : A. air
56. The yield of a rapid sand filter is
Correct : D. 30 times
57. Calcium sulphate present in water causes corrosion.
Correct : A. True
58. The water which leaks into sewers from the ground is termed as infiltration.
Correct : A. Yes
59. When the pO value of water is 5, then it has
Correct : D. extremely strong odour
60. Pre-chlorination
Correct : D. all of these
61. The activated sludge process of sewage treatment
Correct : D. all of the above
62. Turbidity of water is expressed in terms of
Correct : A. silica scale
63. The temporary hardness in water is cused due to the salts like
Correct : C. carbonates
64. A valve which allows the water to flow in one direction but prevents its flow in the reverse direction, is known as
Correct : B. reflux valve
65. The rate of filteration
Correct : B. decreases
66. The pipe joint commonly used in pumping stations is
Correct : B. flanged joint
67. The maximum permissible chloride content in water for domestic supplies should not exceed
Correct : A. 250 ppm
68. For high and fluctuating heads
Correct : A. reciprocating
69. The vertical wells provided along the banks of a river to draaw ground water in dry season are called
Correct : D. infiltration wells
70. When manganese is present in water, it reduces the degree of hardness.
Correct : B. No
71. When the chlorine is added beyond the break point, the process of treating the water is known as
Correct : D. super-chlorination
72. The arithmetical increase method of forecasting population gives
Correct : B. lesser value
73. The yield of a surface stream may be obtained by
Correct : D. all of these
74. The natural process in which the oxygen of water of streams is consumed by sewage and at the same time, it is replenished (filled again) by the atmosphere, is known as
Correct : C. self purification
75. Biological action is used in
Correct : C. trickling filters
76. Slow sand filter is more efficient for the removal of
Correct : A. bacteria
77. Water test is conducted for house plumbings.
Correct : B. No
78. The average consumption of water for commercial use varies from 20 to 25% of total consumption.
Correct : A. Yes
79. The water obtained from the tube wells is known as
Correct : B. sub-surface water
80. In lime soda process, the pH value of treated water is increased.
Correct : A. True
81. The water obtianed from
Correct : D. artesian wells
82. Rapid sand filter can remove bacterias upto an extent of
Correct : C. 80% to 90%
83. Wrought iron pipes are more costly and are
Correct : A. less
84. Suspended impurities consist of
Correct : C. bacteria
85. The water bearing strala i.e. layers of sand, gravel etc, is called
Correct : A. an acquifer
86. The area of the openings in screens should be such that the velocity of flow through them does not exceed
Correct : A. 0.75 to 1 m/s
87. In secondary treatment of sewage, the operation which takes place is
Correct : B. removal of fine dissolved organic material
88. The presence of hydrogen sulphide in water causes
Correct : C. aciity
89. Which of the following statement is wrong?
Correct : D. none of the above
90. The water from kitchens, bathrooms, wash basins is called
Correct : B. sullage
91. The pipe installed in the house or building drainage to preserve the water seal of a trap is called anti-siphonage pipe.
Correct : A. Right
92. Rapid sand filters are cheap and economical as compared to slow sand filters.
Correct : A. True
93. The suitable layout of a distribution system for well planned cities is
Correct : B. ring system
94. Crystalline hydrates of 'Ice" of chlorine are formed at a temerature of
Correct : A. below 10?C
95. The coagulation is not required in
Correct : A. slow sand
96. The detention time for an ordinary plain sedimentation tank is
Correct : C. 6 to 8 hours
97. The alum when mixed with water as a coagulant,