Public Health Engineering MCQs Practice Set

1.The water supply system means

• The entire scheme of collection and disposal of liquid waste
• The complete layout from the source of supply to the distribution (Ans)
• Construction of reservoirs
• Construction of canals

2.The water obtained from the tube wells is known as

• Surface water
• Sub-surface water (Ans)
• Run-off
• Potable water

3. The water obtained from ………………….. is generally known as underground water.

• Infiltration galleries
• Springs (Ans)
• Rivers
• Wells

4. The water obtained from ………………….. is generally known as sub-surface water.

• Rains
• Rivers
• Reservoirs
• Artesian wells (Ans)

5.The horizontal tunnels constructed at shallow depths along the banks of a river to intercept the ground water table are called

• Canals
• Infiltration galleries (Ans)
• Springs
• Lakes

6.The vertical wells provided along the banks of a river to draw ground water in dry season are called

• Open wells
• Tube wells
• Artesian wells
• Infiltration wells (Ans)

7.A pipe sunk into the ground to tap the underground water is called

• Open well
• Tube well (Ans)
• Artesian well
• Infiltration well

8.When in the previous strata, the surface of water surrounding the well is at atmospheric pressure, the well is known as

• Gravity well (Ans)
• Artesian well
• Open well
• Deep well

9.The earth’s water circulatory system is known as

• Water cycle
• Hydrological cycle (Ans)
• Precipitation cycle
• All of these

10.An artesian spring is formed

• When an aquifer gets exposed in a valley against a vertical cut
• Due to continuous fault in a rock through which water under pressure comes out
• When a porous strata gets enclosed between two impervious strata (Ans)
• None of the above

11.The quantity of water available from an infiltration gallery depends upon the

• Size of gallery
• Nature of soil
• Yield of source
• All of these (Ans)

12.The continuous flow of water may be expected from

• Surface springs
• Artesian springs (Ans)
• Gravity springs
• All of these

13.The layers such as sand and gravel which allow the water to pass through them are known as

• Previous layers
• Aquifers
• Water bearing strata
• All of these (Ans)

14.The water bearing strata i.e. layers of sand, gravel etc is called

• An acquifer (Ans)
• An aquiclude
• An aquifuge
• Zone of saturation

15.The layers such as lime stone and sand stone which do not allow the water to pass through them are known as

• Acquifers
• Aquiclude (Ans)
• Aquifuge
• None of these

16.The proportion of soil through which lateral movement of water takes place is called

• Water table
• An aquiclude
• Zone of saturation (Ans)
• None of these

17.The open wells or dug wells are also known as

• Shallow wells
• Draw wells
• Percolation wells
• All of these (Ans)

18.The most important source of water for public water supply is

• Lake
• Pond
• River
• Sea (Ans)

19. The open wells or dug wells

• Act as a small storage reservoir
• Are suitable for a small discharge
• Are cheap in construction
• All of these (Ans)

20.The water of a river has an important property called

• Turbidity
• Self purification (Ans)
• Permeability
• Infiltration capacity

21.Run-off is the water which flows

• In infiltration galleries
• In sewer pipes
• Due to leakage of pipes
• In rivers (Ans)

22.According to Vermule’s formula, the annual run-off (F) in cm is given by

• F = R + (0.279 + 0.116 R) (0.063 T – 0.47)
• F = R – (0.279 + 0.116 R) (0.063 T + 0.47) (Ans)
• F = R – K (1.8 T + 32)
• F = R + K (1.8 T – 32)

Where                R = Annual rainfall in cm,

                            T = Mean annual temperature in ^oC, and

                            K = A constant.

23.The formula, F = R – K (1.8 T + 32), for obtaining the annual run-off is known as

• Justin’s formula
• Vermule’s formula
• Inglis formula
• Khosla’s formula

24.The growth of population may be conveniently represented  by

• Semi-logarthmic curve
• Logistic curve (Ans)
• Straight line curve
• All of these

25.The yield of a surface stream may be obtained by

• Cross-section velocity method
• Stream gauging
• Chemical method
• All of these (Ans)

26. The yield of a underground source may be obtained by

• Pumping test
• Recupating test
• Both (a) and (b) (Ans)
• None of these

27.The yield of the well depends upon the

• Permeability of the soil
• Position of water table
• Depth of well in impervious layer
• All of these (Ans)

28. The yield of the well is measured in

• Cum/h
• Litres/h
• Either (a) or (b) (Ans)
• None of these

29.The amount of water collected in a reservoir is divided into three portions and the order of their existance from bottom to the top is

• Useful storage, surcharge storage, dead storage
• Useful storage, dead storage, surcharge storage
• dead storage, Useful storage, surcharge storage (Ans)
• none of the above

30.In India, as per Indian standards, water consumption per capita per day for domestic purpose is

• 85 litres
• 100 litres
• 115 litres
• 135 litres (Ans)

31.The domestic use of water amounts of ……………. Of the total water requirements per capita per day.

• 20%
• 30%
• 40%
• 50% (Ans)

32.According to Indian standards, the consumption of water per capita per day for nursing homes, boarding schools and hostels is

• 85 litres
• 100 litres
• 115 litres
• 135 litres (Ans)

33. According to Indian standards, 45litres of water per person per day is provided in case of

• Hotels
• Hostels
• Offices (Ans)
• All of these

34.Which of the following formula is used for computing the quantity of water for fire demand?

• Freeman’s formula
• Kuichling formula
• Buston formula
• All of these (Ans)

35.In designing a water works for a city to meet the water demand for public use, a prevision of about …………………… of the total consumption is made.

• 5 %
• 10 % (Ans)
• 20 %
• 25 %

36.The design period for a water supply project is taken as

• 5 to 10 years
• 10 to 15 years
• 15 to 20 years
• 20 to 30 years (Ans)

37.The water mains should be designed for ………………….. of the average daily water requirement.

• 100%
• 150%
• 225% (Ans)
• 250%

38.For large cities, the suitable method for forecasting population is

• Arithmetical increase method (Ans)
• Graphical method
• Geometrical increase method
• Comparative method

39.The arithmetical increase method of forecasting population gives …………….. as compared to geometrical increase method.

• Same value
• Lesser value (Ans)
• Higher value

40.Suspended impurities consist of

• Iron
• Chlorine
• Bacteria (Ans)
• All of these

41.Dissolved impurities consist of

• Bacteria
• Iron (Ans)
• Slit
• Fungi

42.The presence of bacteria in water causes

• Hardness
• Alkalinity
• Diseases (Ans)
• Bad taste

43.Colloidal impurities if associated with organic matter having bacterias becomes the chief source of

• Hardness
• Epidemic (Ans)
• Alkalinity
• Bad taste

44.The presence of calcium and magnesium chloride in water causes

• Softening
• Bad taste
• Hardness (Ans)
• turbidity

45.The ground water is generally free from ……………… impurities.

• Suspended (Ans)
• dissolved

46.The finely divided dispersion of solid particles which are not visible to the naked eye and cannot be removed by ordinary filters are known as

• Suspended impurities
• Dissolved impurities
• Colloidal impurities (Ans)
• None of these

47.The turbidity in water is caused due to

• Silt
• Clay
• Finely divided organic matter
• All of these (Ans)

48. Suspended impurities include

• Algae
• Protozoa
• Fungi
• All of these (Ans)

49.The presence of sodium chloride in water

• Causes bad taste
• Softens the water (Ans)
• Increases hardness of water
• Stops epidemic

50.The sodium carbonate in water

• Causes bad taste
• Softens the water (Ans)
• Increases hardness of water
• Stops epidemic

51.The presence of ………………… causes red colour in water.

• Iron (Ans)
• Manganese
• Sodium fluoride
• Calcium carbonate

52.When lead is present in water, it

• Changes its colour
• Causes turbidity
• Causes alkalinity
• None of these (Ans)

53.Turbidity is the measure of resistance to the passage of ………….. through the water.

• Light (Ans)
• Air

54. Turbidity of water is expressed in terms of

• Silica scale (Ans)
• Platinum cobalt scale
• P^O value
• None of these

55.The colour of water is expressed in numbers of a

• Silica scale (Ans)
• Platinum cobalt scale (Ans)
• P^O value
• None of these

56.The odour of water can be determined by

• Thermometer
• Osmoscope (Ans)
• Jackson’s turbidimeter
• None of these

57.The commercial osmoscope is graduated with P^Ovalues from

• 0 to 5 (Ans)
• 5 to 10
• 10 to 15
• 15 to 20

58.When the P^Ovalue of water is 5, then it has

• No perceptible odour
• Distinct odour
• Faint odour
• Extremely strong odour (Ans)

59. The maximum permissible temperature for domestic supply is

• 5 to 10^oC
• 10 to 15^oC (Ans)
• 15 to 20^oC
• 20 to 25^oC

60. The maximum permissible colour for domestic supplies, on platinum cobalt scale is

• 5 to 10 ppm
• 10 to 20 ppm (Ans)
• 20 to 30 ppm
• 30 to 40 ppm

61.Odours and tastes may result due to the presence of

• Micro-organisms either dead or alive
• Dissolved gases such as oxygen, carbon dioxide, methane etc.
• Mineral substances such as sodium chloride, iron compounds etc.
• All of the above (Ans)

62.The maximum permissible turbidity for domestic supplies, on silica scale is

• 5 to 10 ppm (Ans)
• 10 to 20 ppm
• 20 to 30 ppm
• 30 to 40 ppm

63.High turbidity of water can be determined by

• Turbidity tube
• Jacksons turbidimeter (Ans)
• Baylis turbidimeter
• Hellipe turbidimeter

64.Low turbidity of water can be determined by

• Turbidity tube
• Jacksons turbidimeter
• Baylis turbidimeter (Ans)
• Hellipe turbidimeter

65. The maximum permissible total solid content in water for domestic purposes should not exceed

• 300 ppm
• 400 ppm
• 500 ppm (Ans)
• 1000 ppm

66. The maximum permissible hardness in water for drinking purposes should not exceed 100 ppm.

• Correct (Ans)
• Incorrect

67. The maximum permissible chloride content in water for domestic supplies should not exceed

• 250 ppm (Ans)
• 350 ppm
• 450 ppm
• 550 ppm

68.p^H value is a symbol for ………………. Concentration.

• Magnesium
• Hydrogen (Ans)
• Calcium
• Sodium

69.Residual chlorine in water is determined by ………….. method.

• Versenate
• Starch-iodide (Ans)

70.The product of H⁺ ions and OH^– ions in a water solution is equal to 

• 0
• 10^-1
• 10^-7
• 10^-14 (Ans)

71.The maximum acidity in water will occur at a p^H value of

• 0 (Ans)
• 2
• 7
• 14

72.The most common cause of acidity in water in

• Hydrogen
• Oxygen
• Carbon dioxide (Ans)
• All of these

73.When the p^H value of water is …………………….. the water is said to be acidic.

• Equal to 7
• Less than 7 (Ans)
• More than 7

74. When the p^H value of water is more than 7, it represents ………… water.

• Neutral
• Acidic
• Alkaline (Ans)

75.The alkalinity in water is caused by

• Sodium carbonate
• Potassium carbonate
• Calcium hydroxide
• All of these (Ans)

76.The maximum permissible chlorine content for public supplies should be between

• 1 to 0.2 ppm (Ans)
• 3 to 0.4 ppm
• 3 to 0.4 ppm
• 3 to 0.4 ppm

77. The maximum permissible quantity of iron and manganese in water for domestic purposes should be

• 1 ppm
• 3 ppm (Ans)
• 6 ppm
• 8 ppm

78.The p^H value of water for public supplies is limited from

• 5 to 6.5
• 5 to 8 (Ans)
• 8 to 10.5
• 5 to 15

79.The quantity of arsenic in water for domestic purposes should not be more than 0.05 ppm.

• True (Ans)
• False

80.The maximum permissible quantity of lead in water for domestic supplies is

• 01 ppm
• 05 ppm (Ans)
• 50 ppm
• 1 ppm

81.The copper contents in water for domestic purposes should not be …………………. 3 ppm.

• Less than
• More than (Ans)

82.Sodium carbonate causes ………….. of water.

• Hardness
• Softness (Ans)

83. The maximum permissible fluorine content in water for domestic supplies should be

• 15 ppm
• 5 ppm (Ans)
• 15 ppm
• 150 ppm

84.Sphere shaped bacterias are called

• Spirilla
• Bacilli
• Cocci (Ans)
• Trichobacteria

85.B-coli or E-coli are harmless organisms but their presence in water indicates the

• Presence of pathogenic bacteria (Ans)
• Absence of pathogenic bacteria
• Presence of non-pathogenic bacteria
• Absence of non-pathogenic bacteria

86.Membrane filter technique is used for testing

• E-coli (Ans)
• Copper
• pathogenic bacterias
• none of these

87.Water is ………. When pathogenic bacterias are present.

• Safe
• Harmful (Ans)

88.The bacteria which require oxygen for their survive is known as

• Anaerobic bacteria
• pathogenic bacteria
• aerobic bacteria (Ans)
• non-pathogenic bacteria

89.The bacteria which can survive without oxygen is called

• Anaerobic bacteria (Ans)
• pathogenic bacteria
• aerobic bacteria
• non-pathogenic bacteria

90.Bacterias which cause disease are called

• Anaerobic bacterias
• Facultative bacterias
• aerobic bacterias
• none of these (Ans)

91.The total count of bacteria per cubic centimetre for domestic purposes varies from

• 0 to 100 (Ans)
• 100 to 150
• 150 to 200
• 200 to 250

92.Copper sulphate is the most common chemical used for controlling

• Bacteria
• Algae (Ans)
• Silt
• Mineral matter

93.Bio-chemical oxygen demand (B.O.D.) of safe drinking water must be

• 0 (Ans)
• 10
• 50
• 100

94.The method adopted for removing, bushes branches,debries etc. from water is known as

• Sedimentation
• Coagulation
• Screening (Ans)
• Filteration

95.In the process of screening, the screens should be inclined at an angle of

• 10^o to 20^o
• 30^o to 40^o
• 45^o to 60^o (Ans)
• 70^o to 85^o

96.The area of the openings in screens should be such that the velocity of flow through them does not exceed.

• 75 to 1 m/s (Ans)
• 5 to 3 m/s
• 3 to 5 m/s
• 5 to 6 m/s

97.Plain sedimentation is a process of retaining water in a basin so that the suspended particles settles down as a result of the

• Action of sun-rays
• Action of gravity and forces (Ans)
• Action of velocity of the particles
• None of these

98.The rate of settling of a particle in water depends upon the

• Viscosity of water
• Density of water
• Specific gravity of particle
• All of these (Ans)

99.The detention time for an ordinary plain sedimentation tank is

• 1 to 2 hours
• 2 to 4 hours
• 6 to 8 hours (Ans)
• 20 to 24 hours

100.In a plain sedimentation tank, under normal conditions, impurities are removed upto

• 50%
• 60%
• 70% (Ans)
• 80%

101.In the design of a sedimentation time, the essential factor to the considered is

• Period of detention
• Sludge capacity
• Velocity of flow
• All of these (Ans)

102.The velocity of flow in any sedimentation tank should not exceed

• 05 mm/s
• 5 mm/s
• 5 mm/s (Ans)
• 50 mm/s

103. The length of rectangular sedimentation tank should not be more than……………………. The weight of the tank

• Twice
• Three times
• Four times (Ans)
• Six times

104. The efficiency of sedimentation tank for a given discharge , can be increased by

• Increasing the depth of tank
• Decreasing the depth of tank
• Increasing the surface area of tank (Ans)
• Decreasing the surface area of tank

105. The most common coagulant is

• MgSO₄
• Alum(Ans)
• Chlorine
• Bleaching powder

106. When turbidity water exist about 45 ppm , coagulation ……………adopted

• Should be
• Should not be

107. In dry feeding type of coagulant , the dose of coagulant is controlled by

• Scrappers
• Worn wheel (Ans)
• Paddles
• None of these

108. Which of the following is not a coagulating agent ?

• Ferric Sulphate
• Ferric Chloride
• Aluminium Sulphate
• Copper Sulphate (Ans)

109. The alum when mixed with water as a coagulant ,

• Does not effect P^H value of water
• Decreases P^H value of water (Ans)
• Increases P^H value of water
• None of these

110. Coagulation is required when the particles are of ……………………

Size.

• Fine (Ans)
• Coarse

111. The volume of a settling basin is large due to

• Large volumes of floc added for coagulation
• Large amount of water entrapped into it
• Greater amount of suspended solids to be removed
• None of the above.

112. The process of purifying water by passing it through a bed of fine granular material , is called

• Screening
• Filtration (Ans)
• Coagulation
• Sedimentation

113. The void space s in the filtering material act like a

• Drain
• Inlet
• Tiny settling basin(Ans)
• Outlet

114. The organic impurities in water form a layer on the top of a filtering media. Such a layer is called

• Permeable layer
• Filtering layer
• Dirty skin(Ans)
• None of these

115.The sand, used for filteration, should not loose weight more than …………….. when placed in hydrochloric acid for 24 hours.

• 5%
• 5% (Ans)
• 5%
• 10%

116.The rate of filteration ………………. When the water is filtered through a bed of very fine sand.

• Increases
• Decreases (Ans)

117.The effective size of sand particles for slow sand filters varies from

• 30 to 0.35 mm (Ans)
• 35 to 0.50 mm
• 50 to 0.65 mm
• 65 to 0.75 mm

118. The effective size of sand particles for rapid sand filters varies from

• 30 to 0.35 mm
• 35 to 0.50 mm (Ans)
• 50 to 0.65 mm
• 65 to 0.75 mm

119.The coefficient of uniformity for slow sand filters is

• 35
• 55
• 75 (Ans)
• 05

120.The under drainage system in slow sand filters

• Receives and collects the filtered water (Ans)
• Allows back washing for cleaning the filter
• Both (a) and (b)
• None of these

121. The under drainage system in a rapid sand filters

• Receives and collects the filtered water
• Allows back washing for cleaning the filter
• Both (a) and (b) (Ans)
• None of these

122.The coagulation is not required in ………………. Filters.

• Slow sand (Ans)
• Rapid sand

123.The slow sand filter should be cleaned if the loss of head becomes more than

• 75 m
• 2 m (Ans)
• 2 m
• 5 m

124.After cleaning the slow sand filter, the filtered water should not be used for a period of

• Upto 6 hours
• 6 hours to 12 hours
• 12 hours to 24 hours
• 24 hours to 48 hours (Ans)

125.Cleaning period for a slow sand filter is taken as

• 1 hour to 3 hours
• 1 day to 3 days
• 1 week to 3 weeks
• 1 month to 3 months (Ans)

126.Rate of filteration of a slow sand filter ranges from

• 10 to 100 litres/h/m²
• 100 to 200 litres/h/m² (Ans)
• 200 to 400 litres/h/m²
• 400 to 1000 litres/h/m²

127.Slow sand filter is efficient to remove the bacterias from the raw water to an extent of

• 50%
• 70%
• 85%
• 99% (Ans)

128. Slow sand filter is more efficient for the removal of

• Bacteria (Ans)
• Odour
• Turbidity
• All of these

129.In a rapid sand filter

• Raw water from the source is supplied
• Disinfected raw water is supplied
• Raw water passed through coagulation tank is supplied (Ans)
• Any one of the above

130.The yield of a rapid sand filter is …………….. to that of slow sand filter.

• 10 times
• 15 times
• 20 times
• 30 times (Ans)

131.An arrangement for back washing is provided in

• Slow sand filter
• Sedimentation tank
• Rapid sand filter (Ans)
• All of these

132.In a rapid sand filter, the filter head varies from

• 1 to 1.5 m
• 5 to 2 m
• 2 to 4 m (Ans)
• 4 to 5 m

133.Cleaning of rapid sand filters is done by

• Scraping the top layer of filter media
• Back washing (Ans)
• Providing new sand layers
• All of these

134.Cleaning period for a rapid sand filter is taken as

• 2 to 3 hours
• 2 to 3 days (Ans)
• 2 to 3 weeks
• 2 to 3 months

135.Air binding means accumulation of …………….. in the filter media.

• Air (Ans)
• Impurities

136.Rapid sand filter can remove bacterias upto an extent of

• 60% to 70%
• 70% to 80%
• 80% to 90% (Ans)
• 90% to 99%

137. Rapid sand filter can remove turbidity from water upto an extent of

• 15 to 25 ppm
• 25 to 35 ppm
• 35 to 40 ppm (Ans)
• 40 to 50 ppm

138.Pressure filters are not used for treating municipal water supplies, because

• The rate of filteration is high
• The overall plant capacity is small
• They are inefficient in the removal of turbidity and bacterias
• They are more costly (Ans)

139.In pressure filters, water is forced at a pressure …… the atmospheric pressure.

• Equal to
• Less than
• Greater than (Ans)

140.Pressure filters are best suited for

• Swimming pools
• Railway stations
• Individual industries
• All of these (Ans)

141.The process of killing pathogenic bacterias from water is called

• Sedimentation
• Filteration
• Coagulation
• Disinfection (Ans)

142.The most commonly used disinfectant for drinking water throughout the world is

• Alum
• Nitrogen
• Lime
• Chlorine (Ans)

143.The ideal method of disinfection of swimming pool water is by

• Chlorination
• Lime treatment
• Ozonisation (Ans)
• Ultra-violet rays

144.The amount of residual chlorine in treated water is determined by the

• Orthotolodine test
• Iodometric test
• Amperometric test
• All of these (Ans)

145.The time of contact for chlorination should be at least

• 5 minutes
• 20 minutes
• 1 hour
• 2 hours

146.The treatment of water with only chlorine is known as

• Plain chlorination (Ans)
• Post chlorination
• Pre- chlorination
• de- chlorination

147. Pre- chlorination

• improves coagulation
• reduces odours
• reduces tastes
• all of these (Ans)

148.To prevent the formation of crystalline hydrates of ‘Ice’ of chlorine, the chlorine supply cylinders are kept at a temperature from

• 10^oC to 20^oC
• 20^oC to 27^oC
• 27^oC to 37^oC
• 38^oC to 42^oC (Ans)

149. crystalline hydrates of ‘Ice’ of chlorine are formed at a temperature of

• Below 10^oC (Ans)
• 15^oC
• 20^oC
• Above 20^oC

150.The apparatus used for feeding chlorine into water is called

• Chlorine tank
• Aeration fountain
• Chlorinator (Ans)
• None of these

151.The residual chlorine ……………. At the break point of chlorination.

• Is zero
• Is maximum
• Reappears (Ans)

152.When the chlorine is added beyond the break point, the process of treating the water is known as

• Plain chlorination
• Post chlorination
• de- chlorination
• super-chlorination (Ans)

153.The process of removing excess chlorine from water is called

• Plain chlorination
• Post chlorination
• de- chlorination (Ans)
• super-chlorination

154.The process of dichlorination is followed by

• Pre-chlorination
• Post chlorination
• super-chlorination (Ans)
• double chlorination

155.The amount of chlorine used for plain chlorination of water is about

• 2 ppm
• 3 ppm
• 4 ppm
• 5 ppm (Ans)

156. The most commonly used chemical for dichlorination of water is

• Sodium thiosulphate
• Sodium sulphate
• Potassium permanganate
• All of these (Ans)

157.In orthotolodine test, safe residual for drinking water is indicated by

• Yellow colour (Ans)
• Green colour
• Lemon yellow colour
• None of these

158.Bleaching powder is

• Slaked lime
• Chloride of lime
• Hypo-chloride of lime
• Hypo-chlorite of lime (Ans)

159.The percentage of chlorine in fresh bleaching powder is

• 20 to 25%
• 25 to 30%
• 30 to 35% (Ans)
• 35 to 40%

160.The temporary hardness in water is caused due to the salts like

• Chlorides
• Nitrates
• Carbonates (Ans)
• Sulphates

161.The permanent hardness in water is caused due to the salts like

• Chlorides
• Nitrates
• Sulphates
• All of these (Ans)

162. The temporary hardness due to calcium bocarbonates can be removed by

• Boiling (Ans)
• Lime process
• Lime-soda process
• Zeolite process

163. The permanent hardness of water can be removed by

• Adding alum
• Adding chlorine
• Boiling
• Zeolite process (Ans)

164.By lime soda process, hardness can be reduced to less than

• 50 ppm (Ans)
• 75 ppm
• 100 ppm
• 150 ppm

165.The lime soda process of water softening

• Requires less quantity of coagulation
• Helps in killing pathogenic bacterias
• Is suitable for turbid and acidic water
• All of these (Ans)

166.Zeolite is

• Hydrated silica
• Sodium silicate (Ans)
• Dehydrated calcium silicate
• None of these

167.In Zeolite process

• No sludge is formed
• Water of varying quality can be treated
• Ferrous and manganese from water are removed
• All of the above (Ans)

168.Zeolite process is also known as

• Base exchange process
• Cation exchange process
• Both (a) and (b) (Ans)
• None of these

169.The aeration of water is done to remove

• Colour
• Odour
• Taste
• All of these (Ans)

170.A sluice valve, in water distribution system, is used to

• Protect the pipe against negative pressure
• Regulate the flow of water through the pipe (Ans)
• Prevent water to flow back in the opposite direction
• All of the above

171.A reflux valve, in water distribution system, is used to

• Protect the pipe against negative pressure
• Regulate the flow of water through the pipe
• Prevent water to flow back in the opposite direction (Ans)
• All of the above

172. A reflux valve is also known as

• Safety valve
• Scour valve
• Air valve
• Check valve (Ans)

173.A scour valve, in water distribution system, is provided at

• Low points (Ans)
• High points
• Junction points
• All of these

174.If the level of source of water is higher than that of the place of consumption, the system adopted for supplying water is

• Pumping system
• Gravitational system (Ans)
• Combined pumping and gravity system
• Any one of these

175.The hydrants are used for tapping water from mains for

• Fire extinguishing
• Street washing
• Flushing sewer lines
• All of these (Ans)

176.The minimum size of a fire hydrant is

• 5 cm
• 10 cm
• 15 cm (Ans)
• 20 cm

177.The valve provided on the suction pipe in a tube well is

• Sluice valve
• Air relief valve
• Pressure relief valve
• Reflux valve (Ans)

178.A pressure relief valve is provided to prevent

• The water flowing out of the suction pipe
• The back flow, when the pump is stooped
• The increase of pressure after certain safe limit (Ans)
• All of the above

179.A valve which allows the water to flow in one direction but prevents its flow in the reverse direction, is known as

• Sluice valve
• Reflux valve (Ans)
• Air relief valve
• Pressure relief valve

180.The corrosion in pipe is due to

• Dissolved oxygen in water
• p^H value of water
• impurities in the material particularly those having lower potential
• all of the above (Ans)

181.The type of joint to be used in pipes depends upon the

• material of pipe
• internal pressure
• conditions of support
• all of these (Ans)

182.The plain ends of cast iron pipes are joined by

• spigot and socket joint
• flanged joint
• victuallic joint
• dresser coupling joint (Ans)

183.The pipe joint commonly used in pumping stations is

• flexible joint
• flanged joint (Ans)
• expansion joint
• spigot and socket joint

184.In order to control the flow of water through pipes, a ………….. is provided.

• Scour valve
• Air valve
• Gate valve (Ans)
• Safety valve

185.In order to prevent water to flow back in opposite direction,we shall use a

• Scour valve
• Air valve
• Gate valve
• Reflux valve (Ans)

186.Under steady low heads ……………….. pumps are used

• Reciprocating
• Centrifugal (Ans)

187.For high and fluctuating heads ………… pumps are used

• Reciprocating (Ans)
• Centrifugal

188.The capacity of the pumps is normally expressed as

• Litres per minute
• Cubic metres per day
• Thousands of litres per hour
• All of these (Ans)

189.For an area developed in haphazard way, the type of layout used for the distribution of pipes is known as

• Dead end system (Ans)
• Ring system
• Radial system
• Grid iron system

190.The suitable layout of a distribution system for well planned cities is

• Dead end system
• Ring system (Ans)
• Radial system
• Grid iron system

191.For a city or to wn with roads of rectangular pattern, the type of layout used for the distribution  of pipes is

• Dead end system
• Ring system
• Radial system
• Grid iron system (Ans)

192.Garbage is a

• Dry waste (Ans)
• Semi-liquid waste
• liquid waste
• none of these

193.The water from kitchens, bathrooms, wash basins is called

• sewage
• sullage (Ans)
• raw sewage
• none of these

194.The quantity of liquid waste which flows in sewers during rainy season is called

• storm sewage (Ans)
• dry weather flow
• sanitary sewage
• industrial waste

195.A sewer which receives storm water, surface run-off and sewage is called a

• common sewer
• combined sewer (Ans)
• branch sewer
• outfall sewer

196. A sewer which receives sewage from the collection system and conducts it to a point of final disposal is called a

• common sewer
• trunk sewer (Ans)
• branch sewer
• outfall sewer (Ans)

197.The human excreta is a ………… waste.

• Dry
• Semi-liquid (Ans)
• Liquid

198.The main object of sewage disposal is

• To dispose off properly human excreta to a safe place before it creates unhealthy conditions in the locality
• To dispose off waste water from an area so that it may not become breeding place for mosquitoes
• To dispose off the sewage after giving it treatment so that the receiving land may not get polluted
• All of the above (Ans)

199.A pipe conveying sewage from the plumbing system of a singe building to a common sewer or to the point of immediate disposal is called

• Common sewer
• House sewer (Ans)
• Lateral sewer
• Outfall sewer

200.A sewer which receives discharge of a number of house sewers is called a

• Common sewer
• Trunk sewer
• Lateral sewer (Ans)
• Branch sewer

201. A sewer which gets discharge from two or more main sewers is called

• Main sewer
• Trunk sewer (Ans)
• Combined sewer
• Intercepting sewer

202.The self cleaning velocity, recommended for Indian conditions, in order to prevent settling down of sewage at the bottom or on the sides of a large sewer is

• 25 m/s
• 50 m/s
• 75 m/s (Ans)
• 5 m/s

203.The method in which different types of refuse are collected, carried and disposed off separately is called

• Conservancy method
• Dry method
• Water carriage method
• Either (a) or (b) (Ans)

204.The water carriage sewage system removes

• Domestic sewage
• Industrial sewage
• Storm sewage
• All of these (Ans)

205.A combined system will be favourable when

• The sewers are to be laid in rocks
• The finances are limited
• The topography is flat necessitating deep excavation for combined sewers
• The locality to be served has narrow streets (Ans)

206.House plumbing is difficult in ………………… system.

• Separate (Ans)
• Combined

207.A separate system will be favourable when

• The sewers are to be laid in rocks
• The finances are limited
• The topography is flat necessitating deep excavation for combined sewers
• All of the above (Ans)

208.The sanitation system in which a small portion of storm water is allowed to enter in the sanitary sewage sewers and the remaining storm water flows in separate set of sewers, is known as

• Separate system
• Combined system
• Partially Separate system (Ans)
• Partially Combined system

209.The storm sewers are essentially required to

• Avoid creation of unfavourable healthy conditions
• Improve the general appearance of the city
• Dispose off the first washings of early showers as quickly as possible
• All of the above (Ans)

210.According to Fanning’s formula, the quantity of storm water (Q) in litres per second is given by

• Q = CA^2/3
• Q = CA^5/8 (Ans)
• Q = CA^3/4
• Q = CA^3/2

Where                      A = Area in square kilometres, and

C = A constant

211.The quantity of storm water (Q) in litres per second is given by Q = CA^3/4 . This formula is called

• Fanning’s formula
• Ryve’s formula
• Dicken’s formula (Ans)
• Inglis formula

212.The internal diameter of the sewer should not be less than

• 15 cm (Ans)
• 25 cm
• 50 cm
• 75 cm

213.No deposition will take place in ………………. Sewers.

• Larger
• Smaller (Ans)

214.For house drainage and lateral connections, we shall use

• Stone ware sewers (Ans)
• Cast iron sewers
• Concreate sewers
• Masonry sewers

215.Egg-shaped sewers are generally used for

• Separate system
• Combined system
• Partially Separate system
• All of these (Ans)

216.The cross-section recommended for separate system of sewerage is

• Circular (Ans)
• Egg-shaped
• Rectangular
• None of these

217.An egg-shaped cross-section of a sewer

• Is economical than circular cross-section
• Is more stable than circular cross-section
• Provides self cleaning velocity in dry weather (Ans)
• None of the above

218.For the sewers of diameter less than 600 mm, the type of joint preferred is

• Spigot and socket joint (Ans)
• Collar joint
• Bandage joint
• Mechanical joint

219. For the sewers of diameter more than 600 mm, the type of joint preferred is

• Spigot and socket joint
• Collar joint (Ans)
• Bandage joint
• Mechanical joint

220.Manholes are, generally, located

• At all changes of direction
• At all changes of gradients
• At all junctions of main and branch sewers
• All of these (Ans)

221.For large sewers, the maximum distance between manholes should be

• 75 m
• 150 m
• 200 m
• 300 m (Ans)

222.The lower portion of a manhole is known as

• Access shaft
• Base
• Working chamber (Ans)
• Cover

223.The minimum diameter of a manhole cover should be

• 25 cm
• 50 cm (Ans)
• 75 cm
• 100 cm

224.Manholes on sewer lines are provided for

• Periodic cleaning (Ans)
• Providing air for oxidation
• Removal of part of sewerage
• All of these

225.A drop manhole is provided if

• A sewer drops from a height
• A branch sewer discharges into the main sewer at a higher level (Ans)
• Both (a) and (b)
• None of these

226.The equipment used for checking the levels of the sewer inverts is

• Dumpy level
• Theodolite
• Boning rod (Ans)
• All of these

227.A good trap should

• Not have self cleaning property
• Restrict the flow of water
• Provide an adequate water seal at all times (Ans)
• All of these

228.Ventilation of house drainage is required to

• Relieve the pressure of foul gases
• Dilute the foul air in the drain
• Reduce the obnoxious effect of foul air
• All of these (Ans)

229.In one pipe system of plumbing.

• Only one pipe is provided
• The main pipe is connected directly to the drainage system
• All the traps are fully ventilated and connected to the ventilation pipe
• All of the above

230. In one pipe system of plumbing, waste water is carried away from

• Bath rooms
• Kitchens
• Wash basins
• All of these (Ans)

231.The pipe through which liquid waste carrying human excreta flows, is called

• Waste pipe
• Soil pipe (Ans)
• Vent pipe
• All of these

232.A pipe  used to carry discharge from sanitary fittings like bathrooms, kitchens etc. is called

• Waste pipe (Ans)
• Soil pipe
• Vent pipe
• Anti-siphonage pipe

233.A pipe installed for ventilation purpose is called

• Waste pipe
• Soil pipe
• Vent pipe (Ans)
• Anti-siphonage pipe

234.Which of the following statement is wrong?

• The water closets should be such that excreta do not stick to it
• The trap prevents the entry of foul gases
• The trap should have self cleaning velocity
• The water closet is provided for receiving garbage. (Ans)

235.The anti-siphonage pipe is not required in

• One pipe system
• Two pipe system
• Single stack system (Ans)
• None of these

236.The most suitable excreta disposal unit for human excreta is

• Privy pit (Ans)
• Cess pool
• Soak pit
• None of these

237.The underground structure in the form of a circular or rectangular tank for the purposes of admitting sewage into it from the intercepting chamber is called a

• Septic tank
• Cess pool (Ans)
• Privy pit
• Soak pit

238.The privy pit should be located at least ……….. from the well or other ground water supply.

• 3 m (Ans)
• 10 m
• 30 m
• 50 m

239.A septic tank is a

• Sedimentation tank
• Digestion tank
• Combination of sedimentation and digestion tank (Ans)
• Aeration tank

240.The effluents from the septic tank are discharged into

• Soak pit (Ans)
• Drainage
• Oxidation pond
• Sewer

241.The equipment used for removing paper and rags from sewers is called

• Gouge
• Scoop
• Claw (Ans)
• Scraper

242. The equipment used for cleaning the sewers easily is called

• Gouge
• Scoop
• Claw
• Scraper (Ans)

243.Land disposal of sewage will be favourable where

• The rivers run dry or have a small flow during summer (Ans)
• Rainfall is very high
• Climate is wet and rates of evaporation is low
• All of the above

244.Disposal by dilution will be suitable where

• There are strong forward currents
• There is no back currents
• The sewage arriving at the out fall point is fresh and non-septic
• All of the above (Ans)

245.When the sewage is to be distributed over a level area surrounded by dykes (i.e. trenches), the method of sewage used is called

• Flooding (Ans)
• Surface irrigation
• Ride and furrow
• Spray irrigation

246.Which of the following statement is wrong?

• For land disposal, large areas with preferably snady types of soil are required
• The land disposal requires either preliminary or primary treatment of sewage
• The land disposal saves the inland stream from getting polluted by sewage.
• None of the above (Ans)

247.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

• Oxidation
• Deoxidation
• Self purification (Ans)
• Sedimentation

248.The minimum dissolved oxygen required in water to save the aquatic life is

• 1 ppm
• 2 ppm
• 4 ppm (Ans)
• 8 ppm

249.The biochemical treatment of sewage effluent is a process of

• Oxidation (Ans)
• Deoxidation
• Self purification
• Sedimentation

250.The amount of oxygen consumed by sewage from an oxidising agent like potassium dichromate is termed as

• Bio-chemical oxygen demand (B.O.D.)
• Chemical oxygen demand (C.O.D.) (Ans)
• Relative stability
• None of these

251.The percentage ratio of the oxygen available in sewage to the oxygen required to satisfy one stage of bio-chemical oxygen demand (B.O.D) is termed as

• Chemical oxygen demand
• Oxygen consumed
• Relative stability (Ans)
• Bio-oxygen demand

252.Aerobic bacterias takes place in the ……….. of light.

• Presence (Ans)
• Absence

253.In preliminary treatment of sewage, the operation which takes place, is

• Removal of fine suspended particles
• Removal of fine dissolved organic material
• Removal of lighter floating material (Ans)
• Removal of harmful bacterias and other organisms

254.In secondary treatment of sewage, the operation which takes place, is

• Removal of heavier suspended inorganic material
• Removal of fine dissolved organic material (Ans)
• Removal of harmful bacterias
• All of the above

255. The secondary treatment of sewage is carried out by the use of

• Screens
• Grit chambers
• Trickling filters (Ans)
• Chlorinators

256.In primary settling tank, suspended solids are reduced from

• 10 to 20%
• 20 to 40%
• 40 to 70% (Ans)
• 70 to 90%

257.In high rate activated sludge treatment, bacterias are removed from

• 20 to 40%
• 40 to 60%
• 60 to 80%
• 80 to 95% (Ans)

258.Grit chambers of a sewage plant are usually changed after

• 1 day
• 1 week
• 2 weeks (Ans)
• 4 weeks

259.Grit should be removed from sewage before

• Their disposal in dilution water
• Their lifting by means of pump etc.
• Settling of sewage in sedimentation tank
• All of the above (Ans)

260.Biological action is used in

• Screens
• Sedimentation tanks
• Trickling filters (Ans)
• All of these

261.The sewage is treated by aerobic bacteria action in

• Settling tank
• Trickling filter
• Oxidation pond (Ans)
• All of these

262.The activated sludge

• Contains fertilising constituents
• Indicates the degree of aeration
• Indicates high water content
• All of these (Ans)

263.Sludge treatment is mainly done in order to

• Stabilize the organic matter
• Destroy the pathogenic bacterias
• Reduce the water content
• All of these (Ans)

264. The activated sludge process of sewage treatment

• Requires smaller area for construction of whole unit
• Requires smaller water head for operation than trickling filters
• Has high efficiency
• All of the above (Ans)