330. The cast iron pipes for water supply system are used for
A. durability
B. strength
C. easy connection
D. all the above.
331. The level of underground water is called
A. water level
B. water table
C. negative level
D. invert level.
332. The basin in which the flow of the water is retarted is generally known as
A. settling tank
B. sedimentation tank
C. sedimentation basin
D. All the above.
333. While deriving the Stoke's Law for settling the spherical particle of diameter less than 0.1 mm, the following is taken in consideration
A.The coefficient of drag is equal particle Reynold number.
B. Stream line settling
C. The effective weight of the settling particle is 4/3)13 ? Xwi where Xs and X. are unit weight of particle and water
D. All the above.
334. For sedimentation tanks using coagulants, the normal values of overflow rate ranges between
A. 200-500 litres/hr/m2 of plan area
B. 500-750 litres/hr/m2 of plan area
C. 750-1000 litres/hr/m2 of plan area
D. 1000-1250 litres/hr/m2 of plan area
335. Pick up the correct statement regarding the design of continuous flow type of sedimentation tanks from the following:
A. An increase in the plan area increases the efficiency of the sedimentation tank
B. The depth of sedimentation tank does not have any effect on the efficiency of sediment removal
C. The time that would be required by the flow of water to fill the tank assuming that no outflow occurs, is called the detention time
D. All the above.
336. Which of the following coagulants is us for treating boiler fed water
A. Sodium aluminate (Na2A1204)
B. Aluminium sulphate (Al2(SO4)3.8H20)
C. Ferrous sulphate (FeSO4.7H20)
D. Chlorinated copperas (FeSO4.7H20 + C12)
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