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.Management Sciences
Category: Waste Water Engineering
If the depletion of oxygen is found to be 2.5 mg/litre after incubating 2.5 ml of sewage diluted to 250 ml for 5 days at 20°C, B.O.D. of the sewage is_________________?
0
A. 50 mg/l
B. 100 mg/l
C. 150 mg/l
D. 250 mg/l
If the diameter of a sewer is 150 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
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
Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to_______________?
A. Initial demand
B. First stage demand
C. Carbonaceous demand
D. All of these
Pick up the correct statement from the following?
A. Anaerobic bacteria flourish in the absence of oxygen
B. Aerobic bacteria flourish in the presence of oxygen
C. Facultative bacteria flourish with or without oxygen
D. All the above
In sewers the effect of scouring is more on__________________?
A. Top side
B. Bottom side
C. Horizontal side
D. All sides
The design period in years for pumping plants, is___________________?
A. 1
B. 2 to 3
C. 3 to 5
D. 5 to 10
The following is the physical characteristic of sewage___________________?
A. Turbidity
B. Colour
C. Odour
D. All the above
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