A. Flow velocity is kept 0.09 m/sec
B. Detention period is kept 3 to 4 minutes
C. Organic and inorganic materials are separated
D. All the above
Related Mcqs:
- The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is____________________?
A. 100 cm
B. 110 cm
C. 120 cm
D. 150 cm - The flow velocity in detritus tanks is________________?
A. 0.05 m/sec
B. 0.09 m/sec
C. 1.25 m/sec
D. None of these - Traps_________________?
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 - Pick up the correct statement from the following?
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 - Primary treatment of sewage consists of removal of__________________?
A. Large suspended organic solids
B. Oil and grease
C. Sand and girt
D. Floating materials - Design period of 40 to 50 years is adopted for_________________?
A. Branch sewers
B. Main sewers
C. Trunk sewers
D. All the above - For design purposes, the normal rate of infiltration of ground water into the sewer, is___________________?
A. 500 litres/km/cm
B. 1000 litres/km/cm
C. 1500 litres/km/cm
D. 2000 litres/km/cm - If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is__________________?
A. 1 in 60
B. 1 in 100
C. 1 in 120
D. None of these - When drainage to sewage ratio is 20, the peak dry weather flow is_______________?
A. 20% of the design discharge
B. Slightly less than 5% of the design discharge
C. Slightly more than 5% of the design discharge
D. None of these - The settlement of a particle in sedimentation tank, is affected by_____________________?
A. Velocity of flow
B. Viscosity of water
C. Size and shape of solid
D. All the above
