500 Best Environmental Engineering- MCQ
Q85). Plain sedimentation is a process of retaining water in a basin so that the suspended particles settles down as a result of the
a).Action of sun rays
b).Action of gravity and forces
c).Action of velocity of the particles
d).None of these
Correct Answer:
Action of gravity and forces
Explanation:
Q86). The rate of settling of a particle in water depends upon the
a).Viscosity of water
b).Density of water
c).Specific gravity of particle
d).All of these
Correct Answer:
All of these
Explanation:
Q87). The detention time for an ordinary plain sedimentation tank is
a).1 to 2 hours
b).2 to 4 hours
c).6 to 8 hours
d).20 to 24 hours
Correct Answer:
6 to 8 hours
Explanation:
Q88). In a plain sedimentation tank, under normal conditions, impurities are removed upto
a).0.5
b).0.6
c).0.7
d).0.8
Correct Answer:
0.7
Explanation:
Q89). In the design of a sedimentation tank, the essential factor to be considered is
a).Period of detention
b).Sludge capacity
c).Velocity of flow
d).All of these
Correct Answer:
All of these
Explanation:
Q90). The velocity of flow in any sedimentation tank should not exceed
a).0.05 mm/s
b).0.5 mm/s
c).5 mm/s
d).50 mm/s
Correct Answer:
5 mm/s
Explanation:
Q91). The efficiency of rectangular sedimentation tank for a given discharge, can be increased by
a).Increasing the depth of tank
b).Decreasing the depth of tank
c).Increasing the surface area of tank
d).Decreasing the surface area of tank
Correct Answer:
Increasing the surface area of tank
Explanation:
Q92). The most common coagulant is
a).Magnesium sulphate
b).Alum
c).Chlorine
d).Bleaching powder
Correct Answer:
Alum
Explanation: