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

For house drainage minimum gradient is:


Options are :

  • 1 in 400
  • 1 in 60
  • 1 in 10
  • 1 in 80

Answer :1 in 60

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

Dilution method of disposing off sewage, is not preferred to:


Options are :

  • When sewage is fresh
  • When diluting water has high dissolved oxygen content
  • When diluting water is used for water supply near the point of sewage disposed
  • When the diluting water is having flow currents
  • None of these

Answer :When diluting water is used for water supply near the point of sewage disposed

Pick up the correct statement from the following:


Options are :

  • The materials separated by screens, is called screenings
  • All the above
  • The process of burning the screenings, is known as compositing
  • The process of burning the screenings, is called incineration
  • The screenings are disposed off either by burning or by burial or by dumping

Answer :All the above

In case of Imhoff tanks:


Options are :

  • The velocity of flow is restricted to 0.30 m/minute
  • All the above
  • Surface loading is limited to 30, 000 litres/m of plan area per day
  • The shape is rectangular
  • Detention period is 2 hours

Answer :All the above

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

The algae dies out in the zone of:


Options are :

  • Degradation
  • Recovery
  • Cleaner water
  • Active decomposition

Answer :Degradation

Nitrogen cycle of sewage, is:


Options are :

  • None of these
  • Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates
  • Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
  • Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
  • Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates

Answer :Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen

The standard B.O.D. of water is taken for:


Options are :

  • 3 days
  • 1 day
  • 2 days
  • 10 days
  • 5 days

Answer :5 days

In sewers the effect of scouring is more on:


Options are :

  • Bottom side
  • All sides
  • Horizontal side
  • Top side

Answer :Bottom side

It is customary to design a sewer for D.W.F. on the basis of:


Options are :

  • Twice the average demand
  • Thrice the average demand
  • Four times the average demand
  • Average demand

Answer :Thrice the average demand

The ratio of maximum sewage flow to average sewage flow for mains up to 1 m in diameter, is:


Options are :

  • 1.5
  • 4.0
  • 2.0
  • 3.0

Answer :2.0

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

For a circular sewer of diameter D running partially full with central angle ?:


A.


B.


C.


D.


E.

All the above


Options are :

  • A
  • C
  • E
  • B
  • D

Answer :E

Bio-chemical oxygen demand (BOD) for the first 20 days in generally referred to:


Options are :

  • Initial demand
  • First stage demand
  • Carbonaceous demand
  • All of these

Answer :All of these

Rate of flow of sewage is generally assumed:


Options are :

  • Less than the rate of water supply
  • Equal to the rate of water supply
  • At 150 litres per capita
  • More than the rate of water supply

Answer :Less than the rate of water supply

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

The width of a rectangular sewer is twice its depth while discharging 1.5 m/sec. The width of the sewer is:


Options are :

  • 0.88 m
  • 0.68 m
  • 1.36 m
  • 1.76 m

Answer :1.36 m

The asbestos cement pipes are generally laid:


Options are :

  • At an angle of 30
  • Horizontally
  • Vertically
  • At an angle of 60

Answer :Vertically

The presence of free ammonia in sewage, is detected by:


Options are :

  • Adding pottassium permanganate
  • Boiling
  • Adding sulphuric acid
  • Phenol-di-sulphuric acid

Answer :Boiling

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

Pick up the in-correct statement from the following:


Options are :

  • Catch basins are generally provided in sewers for carrying drainage discharge
  • Inlets are generally provided in all sewers
  • Manholes are provided in sewer pipes at suitable intervals
  • None of these

Answer :Inlets are generally provided in all sewers

The detention time of a circular tank of diameter d and water depth H, for receiving the sewage Q per hour, is:


A.


B.


C.


D.


Options are :

  • B
  • C
  • A
  • D

Answer :A

A sewer pipe contains 1 mm sand particles of specific gravity 2.65 and 5 mm organic particles of specific gravity 1.2, the minimum velocity required for removing the sewerage, is:


Options are :

  • 0.30 m/sec
  • 0.40 m/sec
  • 0.35 m/sec
  • 0.50 m/sec
  • 0.45 m/sec

Answer :0.45 m/sec

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

The drainage area of a town is 12 hectares. Its 40% area is hard pavement (K = 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15)

Assuming the time of concentration for the areas as 30 minutes and using the formula

the maximum run off is:


Options are :

  • 0.10 cumec
  • 0.20 cumec
  • 0.12 cumec
  • 0.15 cumec

Answer :0.15 cumec

In SI units the power of sound is represented in:


Options are :

  • Watts
  • Joules
  • Kgs
  • Newtons

Answer :Watts

The dimensions of a rectangular settling tank are : length 24 m, width 6 m and depth 3 m. If 2 hour detention period for tanks is recommended, the rate of flow of sewage per hour, is:


Options are :

  • 208 cu m
  • 204 cu m
  • 212 cu m
  • 216 cu m
  • 220 cu m

Answer :216 cu m

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

For treating the sewage of a large city, you will recommend:


Options are :

  • A sedimentation tank and an activated sludge treatment plant
  • None of these
  • A plant consisting of Imhoff tanks with low rate trickling filters
  • Sedimentation tanks with high rate trickling filters

Answer :A sedimentation tank and an activated sludge treatment plant

The drop man holes are generally provided in sewers for:


Options are :

  • Cities in plains
  • Industrial areas
  • Large town ships
  • Hilly town ships

Answer :Hilly town ships

For the survival of fish in a river stream, the minimum dissolved oxygen is prescribed:


Options are :

  • 4 PPm
  • 5 PPm
  • 3 PPm
  • 10 PPm

Answer :4 PPm

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

The most dangerous pollutant in vehicular emissions is:


Options are :

  • O3
  • CO
  • SO2
  • CO2

Answer :CO

The screens are fixed:


Options are :

  • Parallel to the direction of flow
  • At an angle 30 to 60 to the direction of flow
  • None of these
  • Perpendicular to the direction of flow

Answer :At an angle 30 to 60 to the direction of flow

Pick up the correct statement from the following:


Options are :

  • Turbidity is more in strong sewage
  • The fresh sewage is practically odourless
  • The black colour indicates septic sewage
  • All the above
  • The sewage omits offensive odours after four hours

Answer :All the above

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

The ratio of the diameter of a circular section and the side of a square section hydraulically equivalent, is:


Options are :

  • 1.095
  • 1.085
  • 1.075
  • 1.065

Answer :1.095

The amount of oxygen consumed by the aerobic bacterias which cause the aerobic biological decomposition of sewage, is known:


Options are :

  • Dissolved Oxygen (D.O.)
  • Chemical Oxygen Demand (C.O.D.)
  • Bio-Chemical Oxygen Demand (B.O.D.)
  • None of these

Answer :Dissolved Oxygen (D.O.)

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