Top 250+ Solved Water and Wastewater Engineering MCQ Questions Answer
Q. Maximum permissible velocity 1.5 m/sec, is adopted in drains
a. With beds of rocks and gravels
b. Lined with stones
c. Both (a) and (b)
d. Neither (a) nor (b)
Q. Pick up the in-correct statement from the following:
a. Manholes are provided in sewer pipes at suitable intervals
b. Catch basins are generally provided in sewers for carrying drainage discharge
c. Inlets are generally provided in all sewers
d. None of these
Q. The moisture content of sludge is reduced from 90% to 80% in a sludge digestion tank. Thepercentage decrease in the volume of sludge, is
a. 25 % (B) (C) (D)
b. 50 %
c. 10 %
d. 5 %
Q. If ‘D’ is the diameter of upper circular portion, the overall depth of New Egg shaped sewersection, is
a. 1.250 D
b. 1.350 D
c. 1.425 D
d. 1.625 D
Q. In trickling filter, B.O.D. is reduced to
a. 30 to 40% (B) (C) (D)
b. 40 to 60%
c. 60 to 80%
d. 80 to 90%
Q. For design of sewers, percentage of sewage discharge is assumed
a. 65 to 70% (B) (C) (D)
b. 70 to 75%
c. 75 to 80%
d. 85%
Q. The grit chambers of sewage treatment plants, are generally cleaned after
a. 2 days (B) (C) (D)
b. 7 days
c. 12 days
d. 14 days
Q. In the activated sludge process
a. Aeration is continued till stability
b. Aeration is done with an admixture of previously aerated sludge
c. Sludge is activated by constant stirring
d. Water is removed by centrifugal action
Q. For detecting the nitrates in sewage, the colour may be developed by adding
a. Potassium permanganate (B) (C) (D)
b. Sulphuric acid and napthamine
c. Phenol-di-sulphuric acid and potassium hydroxide
d. None of these
Q. The settling velocity of a spherical particle of diameter less than 0.1 mm as per Stock's law, is
a. Vs = 418 (Gs- Gw)d [(3T + 70)/100]
b. Vs = 418 (Gs - Gw)d² [(3T + 70)/100]
c. Vs = 218 (Gs - Gw)d² [(3T + 70)/100]
d. Vs = 218 (Gs - Gw)d [(3T + 70)/100]
Q. Inter-distance between ventilation columns in a sewer line is kept
a. 25 to 50 m
b. 50 m to 100 m
c. 100 m to 150 m
d. 150 m to 300 m
Q. Stone ware pipes are
a. Highly resistant to sulphide corrosion (B) (C) (D)
b. Highly impervious
c. Hydraulically efficient because of their smooth interior surface
d. Especially suited to pressure pipes
Q. The intensity of rain is expressed in
a. cm/minute (B) (C) (D)
b. cm/hour
c. cm/day
d. None of these
Q. The ratio of the diameter of a circular section and the side of a square section hydraulicallyequivalent, is
a. 1.095
b. 1.085
c. 1.075
d. 1.065