WASTE WATER ENGINEERING QUIZ

The width of a settling tank with 2 hour detention period for treating sewage 378 cu m per hour, is

5.5 m

5 m

7 m

6.5 m

TRUE ANSWER : ?
YOUR ANSWER : ?

The drainage area of a town is 12 hectares. Its 40% area is hard pavement ( K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula Ps = 900/(t + 60) the maximum run off is

0.20 cumec

0.10 cumec

0.15 cumec

0.12 cumec

TRUE ANSWER : ?
YOUR ANSWER : ?

For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed

3 ppm

4 ppm

10 ppm

5 ppm

TRUE ANSWER : ?
YOUR ANSWER : ?

hydraulically equivalent, the relationship which holds good, is

D3/8 = 4 b3/8

D2/3 = 4 b2/3

D8/3 = 4 b8/3

D3/2 = 4 b3/2

TRUE ANSWER : ?
YOUR ANSWER : ?

Hume steel pipes are

Steel shell coated from inside with cement mortar

Steel pipes

Steel shell coated from outside with cement mortar

Both B and C

TRUE ANSWER : ?
YOUR ANSWER : ?

The laying of sewers is done with

Theodolite

Clinometer

Level

Magnetic compass

TRUE ANSWER : ?
YOUR ANSWER : ?

Hazen’s formula VS = 418 (GS – Gw)d [(3T + 70)/100] is used for the settlement velocity of the particles of diameter

Less than 0.05 mm

Less than 0.1 mm

Less than 0.01 mm

Greater than 0.1 mm

TRUE ANSWER : ?
YOUR ANSWER : ?

If the flame of a miner's safety lamp in the upper layers of the sewer forms an explosive, the sewer certainly contains

Methane

Hydrogen sulphide

Oxygen

Carbon dioxide

TRUE ANSWER : ?
YOUR ANSWER : ?

Skimming tanks are

Those from which sludge is skimmed out

Used to remove the grease and oil

Improved version of grit chambers

Tanks provided with self- cleansing screens

TRUE ANSWER : ?
YOUR ANSWER : ?

If the diameter of a sewer is 100 mm, the gradient required for generating self cleansing velocity is

None of these

1 in 60

1 in 120

1 in 100

TRUE ANSWER : ?
YOUR ANSWER : ?

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