Waste Water Engineering Mcqs - Set 2

1)   Hydraulic mean radius is_______________?

a. Mean radius of sewer
b. Difference in heads between two points in circular pipes
c. Mean of radii in a pipe line of varying cross -sections
d. Cross-sectional area/wetted perimeter
Answer  Explanation 

ANSWER: Cross-sectional area/wetted perimeter

Explanation:
No explanation is available for this question!


2)   The sewer which received discharge from two or more main sewers, is known as_______________?

a. A trunk sewer
b. An outfall sewer
c. A main sewer
d. An intercepting sewer
Answer  Explanation 

ANSWER: A trunk sewer

Explanation:
No explanation is available for this question!


3)   For treating the sewage of a large city, you will recommend_________________?

a. A sedimentation tank and an activated sludge treatment plant
b. A plant consisting of Imhoff tanks with low rate trickling filters
c. Sedimentation tanks with high rate trickling filters
d. None of these
Answer  Explanation 

ANSWER: A sedimentation tank and an activated sludge treatment plant

Explanation:
No explanation is available for this question!


4)   1000 kg of sewage contains________________?

a. 0.112 kg in suspension
b. 0.112 kg in solution
c. 0.225 kg in solution
d. Both A. and C. of above
Answer  Explanation 

ANSWER: Both A. and C. of above

Explanation:
No explanation is available for this question!


5)   R.M.O. expenses include___________________?

a. Running expenses
b. Maintenance expenses
c. Operation expenses
d. All the above
Answer  Explanation 

ANSWER: All the above

Explanation:
No explanation is available for this question!


6)   The sludge does not contain waste water from_________________?

a. Bath rooms
b. Wash basins
c. Kitchen sinks
d. Toilets
Answer  Explanation 

ANSWER: Toilets

Explanation:
No explanation is available for this question!


7)   Pick up the correct statement from the following?

a. Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers
b. 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river
c. Solubility of oxygen in sewage is 95% of that of distilled water
d. All the above
Answer  Explanation 

ANSWER: All the above

Explanation:
No explanation is available for this question!


8)   The rainfall at any place may be determined by__________________?

a. Its intensity
b. Its direction
c. Its frequency
d. All the above
Answer  Explanation 

ANSWER: All the above

Explanation:
No explanation is available for this question!


9)   Pick up the correct statement from the following ?

a. Rate of digestion of sludge is more at higher temperature
b. Thermophilic organisms digest the sludge if the temperature ranges from 40° to 60°C
c. Mesophilic organisms digest the sludge if the temperature is between 25° and 40°C
d. All the above
Answer  Explanation 

ANSWER: All the above

Explanation:
No explanation is available for this question!


10)   The sewer which resists sulphide corrosion, is____________________?

a. Brick sewer
b. Cast iron sewer
c. R.C.C. sewer
d. Lead sewer
Answer  Explanation 

ANSWER: Lead sewer

Explanation:
No explanation is available for this question!


11)   The formula which accepts the value of rugosity coefficient n = 0.012 to be used in Manning’s formula, is given by______________________?

a. Bazin
b. Crimp and Bruges
c. William-Hazen
d. Kutter
Answer  Explanation 

ANSWER: Crimp and Bruges

Explanation:
No explanation is available for this question!


12)   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
Answer  Explanation 

ANSWER: Used to remove the grease and oil

Explanation:
No explanation is available for this question!


13)   If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is_________________?

a. 100 cm
b. 90 cm
c. 80 cm
d. 50 cm
Answer  Explanation 

ANSWER: 100 cm

Explanation:
No explanation is available for this question!


14)   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
Answer  Explanation 

ANSWER: 4 to 8 hours

Explanation:
No explanation is available for this question!


15)   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.
Answer  Explanation 

ANSWER: Both B. and C.

Explanation:
No explanation is available for this question!


16)   If the length of overland flow from the critical point to the mouth of drain is 13.58 km and difference in level between the critical point and drain mouth is 10 m, the inlet time is___________________?

a. 2 hours
b. 4 hours
c. 6 hours
d. 8 hours
Answer  Explanation 

ANSWER: 8 hours

Explanation:
No explanation is available for this question!


17)   In a trickling filter_________________?

a. Filtration process is used
b. Biological action is used
c. Neither A. nor B.
d. Both A. and B.
Answer  Explanation 

ANSWER: Biological action is used

Explanation:
No explanation is available for this question!


18)   The rate of accumulation of sludge in septic tanks is recommended as____________________?

a. 30 litres/person/year
b. 25 litres/person/year
c. 30 litres/person/month
d. 25 litres/person/month
Answer  Explanation 

ANSWER: 30 litres/person/year

Explanation:
No explanation is available for this question!


19)   15 cumecs, the depth d and width are related by For drains up to___________________?

a. d = 0.2 B
b. d = 0.5 B
c. B = 0.2 d
d. B = 0.5 d
Answer  Explanation 

ANSWER: d = 0.5 B

Explanation:
No explanation is available for this question!


20)   Self-cleansing velocity is__________________?

a. Velocity at dry weather flow
b. Velocity of water at flushing
c. Velocity at which no accumulation remains in the drains
d. Velocity of water in a pressure filter
Answer  Explanation 

ANSWER: Velocity at which no accumulation remains in the drains

Explanation:
No explanation is available for this question!