The most dangerous pollutant in vehicular emissions is
A. CO
B. SO2
C. CO2
D. None of the above
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The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. The percentage decrease in the volume of sludge, is
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The design period in years for pumping plants, is
A. 1
B. 2 to 3
C. 3 to 5
D. 5 to 10
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At the junction of sewers
A. Top of smaller sewer is kept lower
B. Top of larger sewer is kept lower
C. Tops of both the sewers are at the same level
D. None of these
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The most effective arrangement for diverting excess storm water into a natural drainage, is
A. Leaping weir
B. Overflow weir
C. Siphon spill way
D. None of these
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Imhoff cone is used to determine
A. Settleable solids
B. Suspended solids
C. Dissolved solids
D. None of these
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The algae dies out in the zone of
A. Degradation
B. Active decomposition
C. Recovery
D. Cleaner water
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For detecting the nitrates in sewage, the colour may be developed by adding
A. Potassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di -sulphuric acid and potassium hydroxide
D. None of these
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For detecting the nitrites in the sewage, the matching colour may be developed by adding
A. Potassium permanganate
B. Sulphuric acid and napthamine
C. Phenol-di -sulphuric acid potassium hydroxide
D. None of these
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The average temperature of sewage in India, is
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Fresh sewage is generally
A. Alkaline
B. Acidic
C. Highly decomposed
D. A source of objectionable odour
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The sewage is pumped up
A. From low lying areas
B. From flat areas
C. From basements
D. All the above
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The dimensions of a rectangular settling tank are: length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is
A. 204 cu.m
B. 208 cu.m
C. 212 cu.m
D. 216 cu.m
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Bottom openings 15 cm × 15 cm in the standing baffle wall are provided
A. 15 cm c/c
B. 22.5 cm c/c
C. 30 cm c/c
D. 50 cm c/c
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Ventilating shafts are provided to a sewer line at every
A. 100 m
B. 150 m
C. 200 m
D. 300 m
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The gradient of sewers depends upon
A. Velocity of flow
B. Diameter of the sewer
C. Discharge
D. All the above
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The laying of sewers is done with
A. Magnetic compass
B. Theodolite
C. Level
D. Clinometer
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Pick up the correct statement from the following:
A. The boning rod is used for checking the levels of the sewer inverts
B. Manhole covers are made circular for the convenience of the cleaning staff
C. A manhole is classified as shallow manhole if its depth is less than 0.9 m
D. All the above
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Pick up the correct statement from the following:
A. The circular section of sewers provides maximum hydraulic mean depth
B. The circular sewers are provided for separate sewerage system
C. The circular sewers work efficiently if the sections run at least half full
D. All the above
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The sewer which received discharge from two or more main sewers, is known as
A. A trunk sewer
B. An outfall sewer
C. A main sewer
D. An intercepting sewer
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