Q.1

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.2

If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains

  • Hydrogen sulphide
  • Carbon dioxide
  • Methane
  • Oxygen
  • None of these.
Q.3

Pick up the incorrect size of stone ware sewers

  • 52.5 cm
  • 67.5 cm
  • 82.5 cm
  • 90 cm
  • none of these.
Q.4

The sewage treatment in septic tanks is due to

  • anaerobic decomposition
  • aerobic decomposition
  • parasitic decomposition
  • none of these.
Q.5

Which of the following pumps in used to pump sewage solids with liquid sewage without clogging the pump is

  • centrifugal pump
  • pneumatic ejector
  • reciprocating pump
  • none of these.
Q.6

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.7

For detecting the nitrates in sewage, the colour may be developed by adding

  • Pottassium permanganate
  • Sulphuric acid and napthamine
  • Phenol-di-sulphuric acid and pottassium hydroxide
  • None of these.
Q.8

The normal values of over flow rates for sedimentation tanks using coagulent, ranges between

  • 25, 000 to 35, 000 litres/sqm/day
  • 40, 000 to 50, 000 litres/sqm/day
  • 50, 000 to 60, 000 litres/sqm/day
  • 80, 000 to 100, 000 litres/sqm/day
  • none of these.
Q.9

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.10

The Brake Horse power of the motor (efficiency 60%) required for a pump of capacity 0.cumec for a total lift ofm, is

  • 10
  • 15
  • 20
  • 25
Q.11

Pick up the correct statement from the following :

  • Rate of digestion of slugde is more at higher temperature
  • Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C
  • Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C
  • 90% of digestion takes place in 30 days at 29°C, the optimum mesophilic temperature
  • All the above.
Q.12

If the flame of a miner's safety lamp in a manhole extinguishes within 5 minutes, the sewer certainly contains

  • Hydrogen sulphide
  • Carbon dioxide
  • Methane
  • Oxygen
  • None of these.
Q.13

Pick up the correct statement from the following :

  • Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers
  • 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river
  • Solubility of oxygen in sewage is 95% of that of distilled water
  • Dissolved oxygen content of sewage, may be determined by Winkler's method
  • All the above.
Q.14

The ratio of maximum sewage flow to average sewage flow for trunk mains having diameters more than 1.m, is

  • 1.5
  • 2.0
  • 3.0
  • 4.0
Q.15

The flow velocity in detritus tanks is

  • 0.05 m/sec
  • 0.09 m/sec
  • 1.25 m/sec
  • none of these.
Q.16

R.M.O. expenses include

  • running expenses
  • maintenance expenses
  • operation expenses
  • all the above.
Q.17

The rate of accumulation of sludge per person per year, is

  • 10 litres
  • 15 litres
  • 20 litres
  • 25 litres
  • 30 litres.
Q.18

The grit and silt of the grit chambers, may not be used for

  • raising low lying areas by dumping
  • concreting
  • both (a) and (b)
  • neither (a) nor (b).
Q.19

The most efficient cross section of sewers in a separate sewerage system is

  • parabolic
  • circular
  • rectangular
  • new egged.
Q.20

The following is the physical characteristic of sewage

  • turbidity
  • colour
  • odour
  • temperature
  • all the above.
Q.21

For drainage pipes in buildings the test applied before putting them to use, is

  • water test
  • smoke test
  • straightness test
  • all the above.
Q.22

The disintegrating pump in which solid matter is broken up before passing out, is

  • centrifugal pump
  • reciprocating pump
  • pneumatic ejector
  • none of these.
Q.23

In a sludge tank, the gas mainly produced, is

  • Oxygen
  • Nitrogen
  • Hydrogen
  • Carbon dioxide
  • Methane.
Q.24

The formula which accepts the value of rugosity coefficient n = 0.to be used in Manning's formula, is given by

  • Bazin
  • Crimp and Bruge
  • William-Hazen
  • Kutter.
Q.25

If asolution of sewage sample is incubated for 5 days at 20°C and the dissolved oxygen depletion was found to be 8 mg/l. The BOD of the sewage is

  • 100 mg/l
  • 200 mg/l
  • 300 mg/l
  • 400 mg/l.
Q.26

The formula which accepts the value of rugosity coefficient n = 0.to be used in Manning's formula, is given by

  • Bazin
  • Crimp and Bruge
  • William-Hazen
  • Kutter.
Q.27

The following is the physical characteristic of sewage

  • turbidity
  • colour
  • odour
  • temperature
  • all the above.
Q.28

For laying a sewer line in a trench of 2 m width, an offset line is marked on the ground parallel to the given centre line at a distance of

  • 100 cm
  • 120 cm
  • 140 cm
  • 160 cm
  • 180 cm.
Q.29

For large sewers, maximum distance between manholes may be

  • 50 m
  • 100 m
  • 200 m
  • 300 m
  • 400 m.
Q.30

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.31

The first stage of neutral process of sludge digestion, is

  • acid fermentation
  • acid regression
  • alkaline fermentation
  • none of these.
Q.32

The design period in years for pumping plants, is

  • 1
  • 2 to 3
  • 3 to 5
  • 5 to 10
Q.33

Lead acetate test in sewer manhole is done to test the presence of

  • Methane gas
  • Hydrogen sulphide
  • Carbondioxide gas
  • Diesel vapours.
Q.34

The Chezy's constant C in the formula V = C rs depends upon

  • size of the sewer
  • shape of the sewer
  • roughness of sewer surface
  • hydraulic characteristics of sewer
  • all the above.
Q.35

Dried sewage after treatment is used as

  • fertilizer
  • building material
  • chemical for lowering B.O.D.
  • base material for paints.
Q.36

Afive day B.O.D. at 15°C of the sewage of a town iskg/day. If the 5 day B.O.D. per head at 15°C for standard sewage is 0.1 kg/day, the population equivalent is

  • 100
  • 1000
  • 5000
  • 10000
Q.37

The use of coarse screens for the disposal of sewage, may be dispensed with by

  • comminutor
  • shredder
  • both (a) and (b)
  • neither (a) nor (b).
Q.38

The density of population overhectares is 250/hectare. If water supply demand per day islitres and sewage discharge isof water supply, the sewage flow in sewers of separate system, is

  • 0.05552 cumec
  • 0.05554 cumec
  • 0.05556 cumec
  • 0.0556 cumec
  • 0.0558 cumec.
Q.39

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
  • 1.0 m/sec.
Q.40

Pick up the correct statement from the following :

  • Turbidity is more in strong sewage
  • The black colour indicates septic sewage
  • The fresh sewage is practically odourless
  • The sewage omits offensive odours after four hours
  • All the above.
Q.41

Pick up the correct statement from the following :

  • In treated sewage, 4 PPm of D.O. is essential
  • Only very fresh sewage contains some dissolved oxygen
  • The solubility of oxygen in sewage is 95% that is in distilled water
  • All the above.
Q.42

If the over land flow from the critical point to the drain is 8 km and the difference in level is 12.4 m, the inlet time is

  • 2 hours
  • 3 hours
  • 4 hours
  • 5 hours.
Q.43

The sewage is pumped up

  • from low lying areas
  • from flat areas
  • from basements
  • across a high ridge
  • all the above.
Q.44

The asbestos cement pipes are generally laid

  • horizontally
  • vertically
  • at an angle of 30°
  • at an angle of 60°.
Q.45

In sewers the gas generally found, is

  • Hydrogen sulphide (H2S)
  • Carbon dioxide (CO2)
  • Methane (CH4)
  • Petrol vapours
  • All the above.
Q.46

Flocculated particles do not change their

  • size
  • shape
  • weight
  • none of these.
Q.47

Dilution method of disposing off sewage, is not preferred to

  • when sewage is fresh
  • when diluting water has high dissolved oxygen content
  • when diluting water is used for water supply near the point of sewage disposed
  • when the diluting water is having flow currents
  • none of these.
Q.48

In olden days the type of section adopted in trunk and out fall sewers was

  • parabolic shaped
  • horse shoe shaped
  • egg shaped
  • circular shaped.
Q.49

For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed

  • 3 PPm
  • 4 PPm
  • 5 PPm
  • 10 ppm.
Q.50

An inverted siphon is designed generally for

  • one pipe
  • two pipes
  • three pipes
  • four pipes.
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