A. Are water seals which prevent the entry of foul gases
B. Are used to trap the rats entering sewers
C. Dissolve the foul gases
D. Create symphonic action to increase the quick disposal of sewerage
A. Mean radius of sewer
B. Difference in heads between two points in circular pipes
C. Mean of radii in a pipe line of varying cross -sections
D. Cross-sectional area/wetted perimeter
A. A trunk sewer
B. An outfall sewer
C. A main sewer
D. An intercepting sewer
A. A sedimentation tank and an activated sludge treatment plant
B. A plant consisting of Imhoff tanks with low rate trickling filters
C. Sedimentation tanks with high rate trickling filters
D. None of these
A. 0.112 kg in suspension
B. 0.112 kg in solution
C. 0.225 kg in solution
D. Both A. and C. of above
A. Running expenses
B. Maintenance expenses
C. Operation expenses
D. All the above
A. Bath rooms
B. Wash basins
C. Kitchen sinks
D. Toilets
A. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers
B. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river
C. Solubility of oxygen in sewage is 95% of that of distilled water
D. All the above
A. Its intensity
B. Its direction
C. Its frequency
D. All the above