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

For trunk sewers more than 1.25 m in diameter, the ratio of the maximum daily sewage flow to the average daily sewage flow is assumed:


Options are :

  • 2.5
  • 3.5
  • 3.0
  • 2.0
  • 1.5

Answer :1.5

For the open drain (N = 0.025) shown in the below figure, the discharge is:


Options are :

  • 28.88 cumecs
  • 29.88 cumecs
  • 26.88 cumecs
  • 27.88 cumecs

Answer :28.88 cumecs

The pH value of sewage is determined with the help of:


Options are :

  • Imhoff Cone
  • Potentiometer
  • None of these
  • Turbidimeter

Answer :Potentiometer

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

Ventilating shafts are provided to a sewer line at every:


Options are :

  • 200 m
  • 150 m
  • 500 m
  • 100 m
  • 300 m

Answer :300 m

Sewer pipes are designed for maximum discharge with 25% to 33% vacant cross-sectional area for:


Options are :

  • All of the above
  • Under estimates of maximum and average flows
  • Unexpected increase in the population
  • Unexpected large scale infiltration of stream water

Answer :All of the above

5 days-biochemical oxygen demand (BOD5) is taken at a temperature of:


Options are :

  • 20C
  • 25C
  • 0C
  • 15C

Answer :20C

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

The most widely used pump for lifting sewage is:


Options are :

  • Reciprocating pump
  • Air pressure pump
  • Pneumatic ejector
  • Centrifugal pump

Answer :Centrifugal pump

Design period of 40 to 50 years is adopted for:


Options are :

  • All the above
  • Branch sewers
  • Main sewers
  • Trunk sewers

Answer :All the above

The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is:


Options are :

  • 0.05556 cumec
  • 0.05552 cumec
  • 0.0556 cumec
  • 0.05554 cumec
  • 0.0558 cumec

Answer :0.05556 cumec

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

Dried sewage after treatment is used as:


Options are :

  • Base material for paints
  • Chemical for lowering B.O.D.
  • Fertilizer
  • Building material

Answer :Fertilizer

The sewerage system consists of:


Options are :

  • All of these
  • Main sewer
  • Branch sewer
  • House sewer
  • Lateral sewer

Answer :All of these

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

If ?w is the unit weight of water, r the hydraulic mean depth of the sewer and S the bed slope of the sewer, then the tractive force exerted by flowing water, is:


Options are :

  • ?w r^(1/2) . S
  • ?w r ?S
  • ?w . r . S
  • ?w r^(2/3) ?S

Answer :?w . r . S

The rational formula for peak drainage discharge, was evolved by:


Options are :

  • All of these
  • Lloyd David
  • Kuichling
  • Fruhling

Answer :All of these

Hazin's formula

is used for the settlement velocity of the particles of diameter:


Options are :

  • Less than 0.1 mm
  • Less than 0.05 mm
  • Less than 0.01 mm
  • Greater than 0.1 mm

Answer :Greater than 0.1 mm

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

If D.O. concentration falls down to zero in any natural drainage, it indicates the zone of:


Options are :

  • Cleaner water
  • Active decomposition
  • None of these
  • Recovery
  • Degradation

Answer :Active decomposition

In sewers designed with self cleansing velocity:


Options are :

  • The bottom is scoured
  • Neither silting nor scouring occurs at the bottom
  • The bottom is silted
  • Both silting and scouring occur at the bottom

Answer :Neither silting nor scouring occurs at the bottom

Dry weather flow is:


Options are :

  • Water supply allowance per capita
  • Average annual rate of flow
  • Average daily rate of flow
  • Average monthly rate of flow
  • None of these

Answer :Water supply allowance per capita

Before discharging the foul sewage into rivers, it is generally treated by:


Options are :

  • All the above
  • Sludge digestion and disinfection
  • Sedimentation
  • Oxidation
  • Screening

Answer :All the above

In areas where rainy season is limited to a few months, the type of sewerage system recommended is:


Options are :

  • None of these
  • Partially separate system
  • Combined system
  • Separate system

Answer :Separate system

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:


Options are :

  • 6 hours
  • 2 hours
  • 4 hours
  • 8 hours

Answer :8 hours

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

Skimming tanks are:


Options are :

  • Improved version of grit chambers
  • Tanks provided with self-cleansing screens
  • Used to remove the grease and oil
  • Those from which sludge is skimmed out

Answer :Used to remove the grease and oil

The suitable cross-section of sewers to carry combined flow, is:


Options are :

  • Circular
  • Rectangular
  • Horse shoe shaped
  • Egg shaped

Answer :Egg shaped

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


Options are :

  • 6.5 m
  • 5.5 m
  • 5 m
  • 7 m
  • 6 m

Answer :7 m

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

The discharge per unit plan area of a sedimentation tank, is generally called:


Options are :

  • Over flow rate
  • Surface loading
  • All the above
  • Over flow velocity

Answer :All the above

With self cleansing velocity in sewers:


Options are :

  • Silting occurs at bottom
  • Both silting and scouring occur at bottom
  • Scouring occurs at bottom
  • Neither silting nor scouring occurs at bottom

Answer :Neither silting nor scouring occurs at bottom

In a sedimentation tank (length L, width B, depth D) the settling velocity of a particle for a discharge Q, is:


A.


B.


C.


D.


Options are :

  • C
  • A
  • B
  • D

Answer :D

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

In detritus tanks:


Options are :

  • Flow velocity is kept 0.09 m/sec
  • All the above
  • Organic and inorganic materials are separated
  • Detention period is kept 3 to 4 minutes

Answer :All the above

rd or th extra space is left in sewer pipes at maximum discharge for:


Options are :

  • All the above
  • Unexpected increase in population
  • Large scale infiltration of storm water
  • Low estimates of the average and maximum flows

Answer :All the above

Drop manholes are the manholes:


Options are :

  • Without manhole covers
  • Without entry ladders
  • Having drains at different levels
  • With depths more than 3.5 m

Answer :Having drains at different levels

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

If n is the rugosity coefficient, r is the hydraulic depth, s is the bed slope of sewer, the velocity of flow in m/sec may be obtained by the formula

evolved by:


Options are :

  • Chezy
  • Kutter
  • Bazin
  • Manning

Answer :Manning

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