Top 250+ Solved Water and Wastewater Engineering MCQ Questions Answer
Q. In sewers the effect of scouring is more on
a. Top side
b. Bottom side
c. Horizontal side
d. All sides
Q. The sewer which resists sulphide corrosion, is
a. Brick sewer
b. Cast iron sewer
c. R.C.C. sewer
d. Lead sewer
Q. In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for adischarge Q, is
a. Q/(B × D)
b. Q/(L × D)
c. Q/L
d. Q/(B × L)
Q. The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning'sformula, is given by
a. Bazin
b. Crimp and Bruges
c. William-Hazen
d. Kutter
Q. The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known
a. Bio-Chemical Oxygen Demand (B.O.D.)
b. Dissolved Oxygen (D.O.)
c. Chemical Oxygen Demand (C.O.D.)
d. None of these
Q. Skimming tanks are
a. Used to remove the grease and oil
b. Those from which sludge is skimmed out
c. Tanks provided with self-cleansing screens
d. Improved version of grit chambers
Q. The most efficient cross-section of sewers in a combined sewerage system is
a. ) Parabolic
b. Circular
c. Rectangular
d. New egged
Q. The detention period for plain sedimentation water tanks, is usually
a. 4 to 8 hours
b. 8 to 16 hours
c. 16 to 24 hours
d. 24 to 36 hours
Q. The factor responsible for purification of sewage in river is
a. Hydrology
b. Dissolved oxygen in water
c. Temperature
d. All the above
Q. Hume steel pipes are
a. Steel pipes
b. Steel shell coated from inside with cement mortar
c. Steel shell coated from outside with cement mortar
d. Both (B) and (C)
Q. To maintain aerobic biological activity, the moisture content of the compost mass should beabout
a. 45 %
b. 50 %
c. 55 %
d. 60 %
Q. The pH value of sewage is determined with the help of
a. Imhoff Cone
b. Turbid meter
c. Potentiometer
d. None of these
Q. The normal value of over flow rates for plain primary sedimentation tanks, ranges between
a. 25,000 to 35,000 litres/sqm/day
b. 40,000 to 50,000 litres/sqm/day
c. 50,000 to 60,000 litres/sqm/day
d. 80,000 to 100,000 litres/sqm/day
Q. Which one of the following statements regarding septic tanks is wrong?
a. A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided
b. The outlet invert level is kept 5 to 7.5 cm below the inlet invert level
c. The minimum width of septic level is 90 cm
d. The depth of tank is kept equal to its width