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This set of Water and Wastewater Engineering Multiple Choice Questions & Answers (MCQs) focuses on Water And Wastewater Engineering Set 5

Q1 | The spacing of bars for perforations in coarse screens used for the treatment of sewage, is

- 20 mm
- 30 mm
- 40 mm
- 50 mm

Q2 | The pH value of fresh sewage is usually

- Equal to 7
- More than 7
- Less than 7
- Equal to zero

Q3 | The maximum depth of sedimentation tanks, is kept

- 3 m
- 3.5 m
- 4 m
- 4.5 m

Q4 | Lead caulked joints are used for laying

- Stone ware pipes
- Earthenware pipes
- C.I. pipes
- G.I. pipes

Q5 | If D is the diameter of a circular sewer and D' is the top horizontal diameter of an equivalent eggshaped section, the relationship which holds good, is

- D' = 0.64 D
- D' = 0.74 D
- D' = 0.84 D
- D' = 0.94 D

Q6 | The spacing of man holes along a straight portion of a sewer is 300 m, the diameter of the sewermay be

- 0.9 cm
- 1.2 m
- 1.5 m
- > 1.5 m

Q7 | The quantity of liquid waste which flows in sewers during the period of rainfall, is known

- Sanitary sewage
- Industrial waste
- Storm sewage
- None of these

Q8 | Nitrogen cycle of sewage, is

- Liberation of ammonia-formation of nitrites-formation of nitrates-liberation of nitrogen
- Liberation of nitrogen-liberation of ammonia-formation of nitrites- formation of nitrates
- Liberation of nitrogen-formation of nitrates-formation of nitrites-liberation of ammonia
- Formation of nitrates-formation of nitrites-liberation of nitrates-liberation of nitrates

Q9 | Depletion of ozone layer in the outer atmosphere may cause

- Lung cancer
- Skin cancer
- Bronchitis
- Heart disorder

Q10 | The minimum diameter of a sewer is kept

- 10 cm
- 15 cm
- 20 cm
- 25 cm

Q11 | Which one of the following gases is most significant as air pollutant?

- Carbondioxide (B) (C) (D)
- Oxygen
- Nitrogen
- Sulphur-dioxide

Q12 | Hazen's formula VS = 418 (GS - Gw)d [(3T + 70)/100] is used for the settlement velocity of theparticles of diameter

- Less than 0.01 mm
- Less than 0.05 mm
- Less than 0.1 mm
- Greater than 0.1 mm

Q13 | For sewers, inverted siphon is provided for

- One pipe
- Two pipes
- Three pipes
- Four pipes

Q14 | For large sewers, maximum distance between manholes may be

- 50 m
- 100 m
- 200 m
- 300 m

Q15 | In sewers designed with self cleansing velocity,

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

Q16 | The value of Chezy's constant C = 157.6/(1.81 + K/ ?? ) is used in

- Chezy's formula
- Bazin's formula
- Kutter's formula
- Manning's formula

Q17 | Pathogens (or pathogenic bacteria’s) in water may cause

- Typhoid
- Cholera
- Dysentery
- All the above

Q18 | The rate of accumulation of sludge per person per year, is

- 10 litres (B) (C) (D)
- 15 litres
- 20 litres
- 25 litres

Q19 | The screens are fixed

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

Q20 | In circular sewers if depth of flow is 0.2 times the full depth, the nominal gradient,

- Is only provided
- Is doubled
- Is trebled
- Is not enough

Q21 | In detritus tanks

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

Q22 | The flow velocity in detritus tanks is

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

Q23 | If the side of a square sewer is 1000 mm, the diameter of a hydraulically equivalent circularsection, is

- 1045 mm
- 1065 mm
- 1075 mm
- 1095 mm

Q24 | A nuisance is experienced in diluting water if dilution factor is less than

- 100
- 60
- 40
- 20

Q25 | A manhole is generally provided at each

- Bend
- Junction
- Change of gradient
- All the above