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

The design period of sewage treatment works in normally:


Options are :

  • 5 - 10 years
  • 15 - 20 years
  • 40 - 50 years
  • 30 - 40 years

Answer :15 - 20 years

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

Pick up the correct statement from the following:


Options are :

  • The circular sewers work efficiently if the sections run at least half full
  • The circular sewers are provided for separate sewerage system
  • The circular section of sewers provides maximum hydraulic mean depth
  • Two sewers of different shapes are said to be hydraulically equivalent if they discharge at the same rate while running full on the same grade
  • All the above

Answer :All the above

Pick up the correct statement from the following:


Options are :

  • The automatic purification of polluted water, is known self purification phenomenon
  • Grab sample is generally obtained from the surface where turbulence mixes the sewage particles
  • The photosynthesis is carried out in the presence of sun light
  • The ratio of the quantity of the diluting water to that of the sewage, is known as dilution factor
  • All the above

Answer :All the above

Kjedahl nitrogen is a mixture of:


Options are :

  • Nitrogen and organic nitrogen
  • All the above
  • Organic nitrogen and ammonia
  • Ammonia and nitrogen

Answer :All the above

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

The sewer which received discharge from two or more main sewers, is known as:


Options are :

  • A trunk sewer
  • An outfall sewer
  • A main sewer
  • An intercepting sewer

Answer :A trunk sewer

Pick up the correct statement from the following:


Options are :

  • Inlets having vertical openings, are called curb inlets
  • Inlets having horizontal openings, are called horizontal inlets
  • Inlets are generally provided at an interval of 30 m to 60 m along straight roads
  • Inlets are provided on the road surface at the lowest point for draining rain water
  • All the above

Answer :All the above

If D is the diameter of upper circular portion, the area of cross-section of a standard egg shaped sewer, is:


A.


B.


C.


D.


Options are :

  • C
  • D
  • A
  • B

Answer :A

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

If a paper moistened with lead acetate for five minutes when placed in manhole turns black. The sewer certainly contains:


Options are :

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

Answer :Hydrogen sulphide

For design of sewers, percentage of sewage discharge is assumed:


Options are :

  • 75 to 80%
  • 70 to 75%
  • 85%
  • 65 to 70%

Answer :75 to 80%

The porosity of sediments in sewer pipes, is usually taken as:


Options are :

  • 0.010
  • 0.012
  • 0.011
  • 0.020
  • 0.013

Answer :0.013

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

The sewage discharge in a detritus tank of a treatment plant is 576 litres/sec with flow velocity of 0.2 m/sec. If the ratio of width to depth is 2, the depth is:


Options are :

  • 110 cm
  • 100 cm
  • 120 cm
  • 150 cm

Answer :120 cm

In case of sewer lines:


Options are :

  • Water test is carried out to check water tightness of the joints
  • Obstruction test is carried out with the. help of smooth ball of diameter 13 mm
  • All the above
  • Test for straightness is carried out with the help of a lamp and mirror

Answer :All the above

The arrangement made for passing the sewer line below an obstruction below the hydraulic gradient lines called:


Options are :

  • Sag pipe
  • Inverted syphon
  • All of these
  • Depressed sewer

Answer :All of these

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

If D is the diameter of upper circular portion, the overall depth of New Egg shaped sewer section, is:


Options are :

  • 1.625 D
  • 1.350 D
  • 1.250 D
  • 1.425 D

Answer :1.625 D

The sewerage system originates from:


Options are :

  • House sewers
  • Branch sewers
  • Out fall sewers
  • Main sewers
  • Lateral sewers

Answer :House sewers

For estimating the peak run off the rational formula Q = 0.0278 KpA was evolved by:


Options are :

  • Lloyd Davis
  • All the above
  • Frubling
  • Kinchling

Answer :All the above

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

In sewage, the solids in mg per litre is:


Options are :

  • 1500 to 2000
  • 1000 to 1500
  • 500 to 1000
  • 100 to 500

Answer :500 to 1000

In sewers the velocity of flow should not be:


Options are :

  • Less than the self-cleansing velocity
  • More than the self-cleansing velocity
  • Less than 10 m/sec
  • More than 20 m/sec

Answer :Less than the self-cleansing velocity

Large diameter sewers subjected to external pressure alone, are reinforced:


Options are :

  • None of these
  • Near the outer surface of the pipe
  • Near the inner surface of the pipe
  • Both A and B
  • With elliptical cage

Answer :With elliptical cage

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

The reduced levels of the string at the consecutive sight rails A and B are 203.575 m, 203.475 m respectively. If the difference of their R.D.s is 10 m, the gradient of the sewer line is:


Options are :

  • 1 in 500 upward
  • 1 in 100 downward
  • 1 in 503 upward
  • 1 in 100 upward

Answer :1 in 100 downward

Assertion (A) : A free board of 0.3 m is provided above the top sewage line in septic tanks

Reason (R) : It helps to accommodate the scum in the septic tank


Options are :

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

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

A safety lamp when inserted in the upper portion of a manhole causes flames. It indicates the presence of:


Options are :

  • Carbondioxide gas
  • Hydrogen sulphide gas
  • Methane gas
  • Petrol vapours

Answer :Methane gas

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

The sewer which transports the sewage to the point of treatment, is called:


Options are :

  • Branch sewer
  • House sewer
  • Out-fall sewer
  • Lateral
  • Main sewer

Answer :Out-fall sewer

The detention time (t) of a settling tank, may be defined as the time required for:


Options are :

  • None of these
  • The flow of sewage to fill the tank
  • A particle to travel from top surface to bottom sludge zone
  • A particle to travel along its length

Answer :The flow of sewage to fill the tank

The ratio of depths at partial flow with central angle ? and at full flow of a sewer, is:


A.


B.


C.


D.


E.


Options are :

  • D
  • A
  • C
  • B
  • E

Answer :C

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

Pick up the correct statement from the following:


Options are :

  • Manhole covers are made circular for the convenience of the cleaning staff
  • All the above
  • A manhole is classified as deep manhole if its depth is more than 1.5 m
  • The boning rod is used for checking the levels of the sewer inverts
  • A manhole is classified as shallow manhole if its depth is. less than 0.9 m

Answer :All the above

A circular sewer section is preferred to because:


Options are :

  • It is cheaper in construction
  • It provides maximum hydraulic mean depth
  • It provides maximum area for a given perimeter
  • All the above

Answer :All the above

The maximum depth of sedimentation tanks, is kept:


Options are :

  • 4 m
  • 3.5 m
  • 4.5 m
  • 3 m

Answer :3 m

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

You are asked to design sewer pipes of diameters 0.4 m to 0.9 m at maximum flow, you will assume the sewer flow running at:


Options are :

  • Full depth
  • Three fourth full
  • Two third full
  • Half full

Answer :Half full

For sewer mains of 0.5 to 1 m diameter, the ratio of maximum daily sewage flow to the average daily sewage flow is assumed:


Options are :

  • 2.0
  • 2.5
  • 1.5
  • 3.0

Answer :2.0

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