Dilution method of disposing of sewage, is not preferred to_______________?
(A) When sewage is fresh
(B) When diluting water has high dissolved oxygen content
(C) When diluting water is used for water supply near the point of sewage disposed
(D) When the diluting water is having flow currents
The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is_________________?
(A) 1 in 100 upward
(B) 1 in 500 upward
(C) 1 in 100 downward
(D) 1 in 503 upward
For the COD test of sewage, organic matter is oxidised by K2Cr2O7 in the presence of________________?
(A) H2SO4
(B) HNO3
(C) HCl
(D) None of these
In sewers the velocity of flow should not be_________________?
(A) More than the self-cleansing velocity
(B) Less than the self-cleansing velocity
(C) Less than 10 m/sec
(D) More than 20 m/sec
In sewers the effect of scouring is more on__________________?
(A) Top side
(B) Bottom side
(C) Horizontal side
(D) All sides
Sewer ventilating columns are generally placed at_______________?
(A) Distances 150 m to 300 m
(B) Upper ends of branch sewers
(C) Every change in the size of sewers
(D) All the above
In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is____________________?
(A) Q/(B × D)
(B) Q/(L × D)
(C) Q/L
(D) Q/(B × L)
The most efficient cross-section of sewers in a combined sewerage system is________________?
(A) Parabolic
(B) Circular
(C) Rectangular
(D) New egged
Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for__________________?
(A) Unexpected large scale infiltration of stream water
(B) Unexpected increase in the population
(C) Under estimates of maximum and average flows
(D) All of the above