In sewers the gas generally found, is_________________?
(A) Hydrogen sulphide (H2S)
(B) Carbon dioxide (CO2)
(C) Methane (CH4)
(D) All the above
If the depth of partial flow in a sewer of diameter 2 m, is 50 cm, its wetted perimeter is____________________ ?
(A) 1/3
(B) 0/2
(C) 0/3
(D) 2 /3
Rate of flow of sewage is generally assumed__________________?
(A) More than the rate of water supply
(B) Equal to the rate of water supply
(C) Less than the rate of water supply
(D) At 150 litres per capita
In R.C. sewer pipes, the percentage longitudinal reinforcement to the cross-sectional area of concrete is kept________________?
(A) 10.0
(B) 5.0
(C) 2.0
(D) 0.25
In primary sedimentation, the 0.2 mm inorganic solids get separated if specific gravity is_________________?
(A) 2.25
(B) 2.50
(C) 2.55
(D) 2.65
hydraulically equivalent, the relationship which holds good, is _______________?
(A) D8/3 = 4 b8/3
(B) D3/8 = 4 b3/8
(C) D2/3 = 4 b2/3
(D) D3/2 = 4 b3/2
Sewer manholes are generally provided at________________?
(A) The change of gradient
(B) The change of direction
(C) The junctions of sewers
(D) All of these
Aerobic activity is maximum_______________?
(A) In freshly produced sewage
(B) At sewer pipes
(C) In sewer treatment plants
(D) None of these
Before discharging the foul sewage into rivers, it is generally treated by_____________________?
(A) Screening
(B) Sedimentation
(C) Oxidation
(D) All the above
In 1000 kg of sewage, the total solids approximate___________________?
(A) 0.5 to 1.0 kg
(B) 1 kg to 2.0 kg
(C) 5 kg to 7.5 kg
(D) 7.5 kg to 10 kg