Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 10

R.M.O. expenses include:


Options are :

  • All the above
  • Running expenses
  • Maintenance expenses
  • Operation expenses

Answer :All the above

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 11

The underground sewers are more subjected to:


Options are :

  • Bending force
  • Compressive force
  • Shearing force
  • Tensile force

Answer :Compressive force

In a trickling filter:


Options are :

  • Biological action is used
  • Both A and B
  • Filtration process is used
  • Neither A nor B

Answer :Biological action is used

Pick up the correct statement from the following:


Options are :

  • Solubility of oxygen in sewage is 95% of that of distilled water
  • Hydrogen sulphide gas in excess, may cause corrosion of concrete sewers
  • Dissolved oxygen content of sewage, may be determined by Winkler's method
  • 4 ppm of Dissolved Oxygen (D.O.) is ensured before discharging the treated sewage in river
  • All the above

Answer :All the above

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 2

The normal value of over flow rates for plain primary sedimentation tanks, ranges between:


Options are :

  • None of these
  • 80, 000 to 100, 000 litres/sqm/day
  • 25, 000 to 35, 000 litres/sqm/day
  • 40, 000 to 50, 000 litres/sqm/day
  • 50, 000 to 60, 000 litres/sqm/day

Answer :40, 000 to 50, 000 litres/sqm/day

The grit chambers of sewage treatment plants, are generally cleaned after:


Options are :

  • 12 days
  • 5 days
  • 7 days
  • 14 days
  • 2 days

Answer :14 days

The coagulant which is generally not used for treating the sewage, is:


Options are :

  • Ferric chloride
  • Chlorinated copperas
  • Ferric sulphate
  • Alum

Answer :Alum

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 3

If the pH value of sewage is 7:


Options are :

  • It is alkaline
  • It is acidic
  • None of these
  • It is neutral

Answer :It is neutral

The sewer that unloads the sewage at the point of treatment is called:


Options are :

  • Main sewer
  • Outfall sewer
  • House sewer
  • Branch sewer

Answer :Outfall sewer

For a continuous flow type of sedimentation tanks:


Options are :

  • Maximum horizontal flow velocity is limited to 0.3 m/minute
  • Capacity of the tank for 24 hours, is kept equal to maximum daily flow of sewage
  • Width of the tank is normally kept about 6 m
  • All the above
  • Length of the tank is normally kept 4 to 5 times the width

Answer :All the above

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 4

For efficient working of a sewer, it must be ensured that:


Options are :

  • None of these
  • Minimum velocity of 0.45 m/sec, is maintained at its minimum flow
  • A maximum velocity of 0.90 m/sec, is maintained at its maximum flow

Answer :Minimum velocity of 0.45 m/sec, is maintained at its minimum flow A maximum velocity of 0.90 m/sec, is maintained at its maximum flow

Acid regression stage of sludge digestion at a temperature 21C extends over a period of:


Options are :

  • 60 days
  • 30 days
  • 90 days
  • 15 days

Answer :90 days

The layers of vegetable wastes and night soil alternatively piled above the ground to form a mound, is called:


Options are :

  • Plateu
  • A heap
  • None of these
  • Windrow

Answer :None of these

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 5

To maintain aerobic biological activity, the moisture content of the compost mass should be about:


Options are :

  • 45%
  • 60%
  • 50%
  • 55%

Answer :55%

Pick up the correct statement from the following:


Options are :

  • All the above
  • The minimum design velocity of sewer pipes is taken as 0.8 m/sec
  • The sewer pipes of sizes greater than 0.4 m diameter are designed as running 2/3rd or 3/4th full at maximum discharge
  • The sewer pipes of sizes less than 0.4 m diameter are designed as running full at maximum discharge

Answer :All the above

In Chezy's formula V = C ?rs for calculating the velocity of flow in circular sewer of diameter D running full, the value of hydraulic mean radius is:


A.

D


B.


C.


D.


E.


Options are :

  • C
  • D
  • A
  • E
  • B

Answer :D

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 6

The temperature affects the:


Options are :

  • Biological activity of bacterias in sewage
  • Solubility of gases in sewage
  • Viscosity of sewage
  • All the above

Answer :All the above

The flow velocity in detritus tanks is:


Options are :

  • 1.25 m/sec
  • None of these
  • 0.09 m/sec
  • 0.05 m/sec

Answer :0.09 m/sec

If the depletion of oxygen is found to be 5 ppm after incubating a 2.5% solution of sewage sample for 5 days at 21C, B.O.D. of the sewage is:


Options are :

  • 100 ppm
  • 250 ppm
  • 50 ppm
  • 200 ppm
  • 150 ppm

Answer :200 ppm

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 7

Cement concrete sewers are only suitable if non-scouring velocity is between:


Options are :

  • 2.5 to 3.0 m/sec
  • 3.0 to 4.0 m/sec
  • 3.5 to 4.5 m/sec
  • 4.5 to 5.5 m/sec

Answer :2.5 to 3.0 m/sec

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


Options are :

  • Methane
  • Hydrogen sulphide
  • None of these
  • Oxygen
  • Carbon dioxide

Answer :Methane

The spacing of bars for perforations in coarse screens used for the treatment of sewage, is:


Options are :

  • 30 mm
  • 40 mm
  • 50 mm
  • 20 mm
  • 100 mm

Answer :50 mm

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 8

If the discharge of a sewer running half is 628 1.p.s., i = 0.001, and n = 0.010, the diameter of the sewer, is:


Options are :

  • 1.69 m
  • 1.39 m
  • 1.49 m
  • 1.79 m
  • 1.59 m

Answer :1.69 m

A manhole is generally provided at each:


Options are :

  • Change of sewer diameter
  • Bend
  • Junction
  • All the above
  • Change of gradient

Answer :All the above

The bottom of the sewage inlet chamber of septic tanks, is provided an outward slope:


Options are :

  • 1 in 15
  • 1 in 25
  • 1 in 20
  • 1 in 10
  • 1 in 5

Answer :1 in 10

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 9

Pick up the correct statement from the following:


Options are :

  • Medium sewers may be cleaned by pills
  • Small sewers are cleaned by flushing
  • Medium sewers are cleaned by cane rodding
  • All the above
  • Large sewers are cleaned by removing the deposited materials

Answer :All the above

In very first stage of decomposition of the organic matter in sewage:


Options are :

  • Nitrites are formed
  • Ammonia is formed
  • Carbondioxide is formed
  • Nitrates are formed

Answer :Ammonia is formed

The following is the physical characteristic of sewage:


Options are :

  • Temperature
  • Colour
  • Turbidity
  • All the above
  • Odour

Answer :All the above

Pick up the correct statement from the following:


A.

Maximum daily flow = 2 times the average daily flow


B.

Maximum daily flow =

x average daily flow


C.

Sewers are designed for minimum permissible velocity at minimum flow


D.

All the above


Options are :

  • C
  • A
  • B
  • D

Answer :D

If a 2% solution of sewage sample is incubated for 5 days at 20C and the dissolved oxygen depletion was found to be 8 mg/l

The BOD of the sewage is:


Options are :

  • 300 mg/l
  • 200 mg/l
  • 400 mg/l
  • 100 mg/l

Answer :400 mg/l

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