Q.1

For complete stabilisation of organic matter in polluted water, it takes

  • 5 days
  • 10 days
  • 20 days
  • 30 days
  • 40 days.
Q.2

The storage capacity of a reservoir may be divided into three zones. The lowest zone is

  • Dead storage
  • Useful storage
  • Surcharge storage
  • None of these.
Q.3

P.V.C. pipes can withstand pressure bead of water upto

  • 25 m
  • 50 m
  • 75 m
  • 100 m
  • 125 m.
Q.4

The factor for the selection of pumping station site, is

  • distance of the source of contamination or pollution
  • height above the H.F.L. of the river
  • future expansion
  • proximity of the site from the railway station
  • all the above.
Q.5

In a rapid gravity filter

  • raw water from the source is supplied
  • disinfected raw water is supplied
  • raw water passed through coagulation tank is supplied
  • none of these.
Q.6

The population of a city inis 50,The average increase in population over last 8 decades isand average incremental increase during 8 decades isThe population of the city based on incremental method, in the yearwill be

  • 55,000
  • 60,500
  • 66,500
  • 72,500
  • 76,500
Q.7

Low turbidity of water is detected by

  • Turbidity tube
  • Jackson turbidity meter
  • Baylis turbidimeter
  • Hellipe turbidimeter
  • None of these.
Q.8
Sunlight
  • helps growth of bacterias
  • impedes growth of algae
  • increases dissolved oxygen content
  • reduces turbidity
Q.9
Pick up the correct statement from the following
  • Detention period for plain sedimentation tanks ranges between 4 to 8 hours
  • Detention period for sedimentation tanks, using coagulants usually ranges between 2 to 4 hours
  • The horizontally flow velocity in sedimentation tanks, is generally limited to 0.3 m/minute
  • All the above.
Q.10
What is turbidity?
  • Solution which contains calcium and magnesium ions.
  • Measure of the extent to which light is either absorbed or scattered by suspended material in water.
  • Trace of metal elements in water.
  • Concentration of the hydrogen ions in water.
Q.11
Hard water contains
  • calcium
  • magnesium bicarbonates
  • magnesium sulphate
  • all the above.
Q.12
Aeration of water is done to remove
  • odour
  • colour
  • bacterias
  • hardness
Q.13
Turbidity of raw water is a measure of
  • suspended solids
  • acidity of water
  • B.O.D
  • none of these.
Q.14
Time of concentration
  • is the time taken, for precipitation
  • duration of rainfall.
  • time taken for all the ran off to reach the drain
  • time taken for the storm water to travel from the most remote point to the drain.
Q.15
Surge tanks are used
  • for storage water
  • to increase the velocity in a pipeline
  • as overflow valves
  • to guard against water hammer.
Q.16
What causes hardness in water?
  • Calcium
  • Arsenic
  • Mercury
  • Rhodium
Q.17
Acidity in water is caused due to
  • Mineral acids
  • Free CO₂
  • Aluminium sulphate
  • All the above.
Q.18
Hard water for public water supply is discarded because
  • it consumes more soap
  • it contains lot of turbidity
  • it contains pathogenic bacterias
  • it possesses bad taste and odour
Q.19
The level of underground water is called
  • water level
  • water table
  • negative level
  • invert level.
Q.20
The population growth curve is
  • S-shaped curve
  • parabolic curve
  • circular curve
  • straight line
Q.21
Water supply system includes
  • digging a well for water
  • construction of dams
  • construction of canals
  • entire arrangement from source to distribution.
Q.22
Asbestos pipes are
  • light in weight and easy to transport
  • highly resistant to corrosion
  • very much smooth and hydraulically efficient
  • all the above
Q.23
If pH value of water is
  • 7 water it is said to be neutral
  • less than 7 it is said to be acidic
  • more than 7 it is said to be alkaline
  • all the above.
Q.24
Continuous flow of water can be expected from
  • gravity springs
  • surface springs
  • artesian springs
  • none of these.
Q.25
Hardness of water is caused due to
  • calcium sulphate
  • magnesium sulphate
  • calcium nitrates
  • calcium bicarbonates
  • all the above.
Q.26
Corrosion of a pipe
  • reduces its life span
  • reduces its carrying capacity
  • adds colour to water
  • all the above.
Q.27
The maximum depth of sedimentation tanks is limited to
  • 2 m
  • 3 m
  • 4 m
  • 5 m
  • 6 m.
Q.28
Which method is used to measure the color of water?
  • Gravimetric analysis
  • Chromatography
  • Tintometer method
  • Hydrometer analysis
Q.29
Rapid gravity filter can only remove turbidity of water upto
  • 15 to 25 gm/litre
  • 25 to 30 gm/litre
  • 30 to 35 cm/litre
  • 35 to 40 gm/litre
Q.30
The efficiency of sedimentation tank does not depend upon
  • depth of tank
  • length of tank
  • detention period
  • velocity of water.
0 h : 0 m : 1 s