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

If D is the diameter of a circular sewer and D' is the top horizontal diameter of an equivalent egg shaped section, the relationship which holds good, is:


Options are :

  • D' = 0.94 D
  • D' = 0.64 D
  • D' = 0.84 D
  • D' = 0.74 D

Answer :D' = 0.84 D

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

'Cowl' is provided at:


Options are :

  • Upper end of the manhole
  • First step in manhole
  • Upper end of ventilating column
  • Lower end of ventilating column

Answer :Upper end of ventilating column

Pick up the incorrect statement from the following:


Options are :

  • The process of decomposing the organic matter under controlled anaerobic conditions, is called sludge digestion
  • The gases produced in sludge digestion process, contain 75% methane
  • Sludge digestion is carried out in sludge tank
  • The gases produced in sludge digestion process, contain 75% carbon dioxide

Answer :The gases produced in sludge digestion process, contain 75% carbon dioxide

For a peak discharge of 0.0157 cumec, with a velocity of 0.9 m/sec, the diameter of the sewer main, is:


Options are :

  • 15 cm
  • 18 cm
  • 10 cm
  • 20 cm
  • 12 cm

Answer :15 cm

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

If the grit in grit chambers is 4.5 million litres per day, its cleaning is done:


Options are :

  • Mechanically
  • Manually
  • Hydraulically
  • Electrically

Answer :Manually

A well oxidized sewage contains nitrogen mainly as:


Options are :

  • None of these
  • Free ammonia
  • Nitrites
  • Nitrates

Answer :Nitrates

During putrifaction process of sewage the gas given off, is:


Options are :

  • Hydrogen
  • Carbon dioxide
  • Ammonia
  • Methane
  • All the above

Answer :All the above

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

Imhoff cone is used to determine:


Options are :

  • None of these
  • Suspended solids
  • Dissolved solids
  • Settlable solids

Answer :Settlable solids

In septic tanks, decomposition of organic bacteria, is done by:


Options are :

  • Aerobic bacteria
  • Both types of bacterias
  • None of these
  • Anaerobic bacteria

Answer :Anaerobic bacteria

The angle subtended by the surface of sewer water with partial flow, at sewer centre is 120, the depth of sewerage is:


Options are :

  • 50 cm
  • 40 cm
  • 60 cm
  • 20 cm
  • 25 cm

Answer :50 cm

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

In a residential colony, sewers of diameters 100 mm, 150 mm and 225 mm were laid with a gradient 1 in 120

Which portion of the sewage system does not choke in due course of time:


Options are :

  • All of these
  • 100 mm dia.
  • 150 mm dia.
  • 225 mm dia.

Answer :225 mm dia.

Drop manholes at the junctions of sewer lines, are provided if:


Options are :

  • Invert level of a branch sewer is more than 60 cm that of the main sewer
  • Sewer line runs along a main road
  • Ordinary manhole cannot be built
  • Two sewer lines intersect

Answer :Invert level of a branch sewer is more than 60 cm that of the main sewer

3.0 ml of raw sewage is diluted to 300 ml. The D.O. concentration of the diluted sample at the beginning of the test was 8 mg/l. After 5 day-incubation at 20C, the DO. concentration was 5 mg/l. The BOD of raw sewerage is:


Options are :

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

Answer :300 mg/l

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

The gas evolved in sewers is:


Options are :

  • All of these
  • Carbondioxide
  • Methane
  • Hydrogen sulphide

Answer :All of these

Assertion (A) : The minimum self cleansing velocity in the sewer, at least once a day, must be generated.

Reason (R) : If certain deposition takes place and is not removed, it obstructs free flow and causes further deposition leading to complete blocking of the sewer


Options are :

  • A is true but R is false
  • A is false but R is true
  • Both A and R are true and R is the correct explanation of A
  • Both A and R are true but R is not a correct explanation of A

Answer :Both A and R are true and R is the correct explanation of A

Discrete or granular particles change their:


Options are :

  • Shape
  • Size
  • Weight
  • None of these

Answer :None of these

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

A nuisance is experienced in diluting water if dilution factor is less than:


Options are :

  • 10
  • 100
  • 20
  • 40
  • 60

Answer :20

The most effective arrangement for diverting excess storm water into a natural drainage, is:


Options are :

  • Siphon spill way
  • Overflow weir
  • None of these
  • Leaping weir

Answer :Siphon spill way

The stone ware sewers:


Options are :

  • Are manufactured from clays and shales
  • Are used for carrying sewage and drainage from houses
  • After casting are dried and burnt at temperature 150C, 700C and 1200C
  • Are generally provided with a water proof cover by vaporising sodium chloride
  • All the above

Answer :All the above

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

Traps:


Options are :

  • Are used to trap the rats entering sewers
  • Are water seals which prevent the entry of foul gases
  • Create syphonic action to increase the quick disposal of sewerage
  • Dissolve the foul gases

Answer :Are water seals which prevent the entry of foul gases

Which one of the following statements regarding septic tanks is wrong:


Options are :

  • A gap of 7.5 cm between the bottom of the covering slab and the top level of scum is provided
  • The depth of tank is kept equal to its width
  • The outlet invert level is kept 5 to 7.5 cm below the inlet invert level
  • The minimum width of septic level is 90 cm

Answer :The depth of tank is kept equal to its width

In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient:


Options are :

  • Is not enough
  • Is doubled
  • Is trebled
  • Is only provided

Answer :Is doubled

The Chezy's constant C in the formula V = C ?rs depends upon:


Options are :

  • Shape of the sewer
  • Roughness of sewer surface
  • Hydraulic characteristics of sewer
  • Size of the sewer
  • All the above

Answer :All the above

Which one of the following part of human body withstands minimum radiation:


Options are :

  • Kidneys
  • Eyes
  • Ovaries/testis
  • Thyroid

Answer :Ovaries/testis

Waste Water Engineering MCQ Practice Questions (Civil Eng) Set 1

In trickling filter, B.O.D. is reduced to:


Options are :

  • 40 to 60%
  • 60 to 80%
  • 30 to 40%
  • 80 to 90%
  • 95%

Answer :60 to 80%

If the depth of flow in a circular sewer is 1/4th of its diameter D, the wetted perimeter is:


A.


B.


C.


D.

?D


Options are :

  • D
  • C
  • B
  • A

Answer :C

Inter-distance between ventilation columns in a sewer line is kept:


Options are :

  • 25 to 50 m
  • 50 m to 100 m
  • 100 m to 150 m
  • 150 m to 300 m

Answer :150 m to 300 m

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

Stoneware sewers are available in size:


Options are :

  • 25 cm
  • 20 cm
  • 10 cm
  • All the above
  • 15 cm

Answer :All the above

Pick up the correct statement from the following:


Options are :

  • The water supply pipes carry pure water free from solid particles
  • The sewers may be carried up and down the hills and valleys
  • None of these
  • The water supply pipes get clogged if flow velocity is less than self cleansing velocity
  • The sewer pipes are generally laid along level hills

Answer :The water supply pipes carry pure water free from solid particles

Imhoff cone is used to measure:


Options are :

  • Settleable solids
  • Total in organic solids
  • Total organic solids
  • Total solids

Answer :Settleable solids

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