Explore topic-wise MCQs in Waste Water Engineering.

This section includes 140 Mcqs, each offering curated multiple-choice questions to sharpen your Waste Water Engineering knowledge and support exam preparation. Choose a topic below to get started.

51.

In India, the average temperature of sewage is __________

A. 10°C
B. 20°C
C. 40°C
D. 80°C
Answer» C. 40°C
52.

The odor in wastewater is measured by __________

A. Osmoscope
B. Chromatography
C. Olfactometer
D. Turbidity meter
Answer» B. Chromatography
53.

______ represents the number of dilutions required to reduce odor.

A. Dispersion
B. Threshold odor number
C. BOD
D. COD
Answer» C. BOD
54.

The odor quality of Amines is __________

A. Rotten egg
B. Fishy
C. Fecal matter
D. Decayed cabbage
Answer» C. Fecal matter
55.

Which of the following instrument is used to measure turbidity?

A. Olfactometer
B. Turbidity meter
C. Colorimeter
D. Spectrophotometer
Answer» C. Colorimeter
56.

The color of the septic sewage is __________

A. Pink
B. Red
C. Black
D. Grey
Answer» D. Grey
57.

The permissible dose of chloride in domestic sewage is __________

A. 120ppm
B. 10ppm
C. 1ppm
D. 250ppm
Answer» B. 10ppm
58.

When the sewage becomes stronger, the turbidity of wastewater?

A. Increases
B. Decreases
C. Becomes constant
D. Slightly decrease
Answer» B. Decreases
59.

Which color indicates the fresh sewage?

A. Pink
B. Red
C. Black
D. Grey
Answer» E.
60.

Imhoff cone is used to measure the _______

A. Suspended solids
B. Settleable solids
C. Dissolved solids
D. Total solids
Answer» C. Dissolved solids
61.

The decomposition of sewage takes place, causing a pungent smell. Which of the following causes the pungent smell?

A. CO₂
B. H₂SO₄
C. HCL
D. H₂S
Answer» E.
62.

________ is used to find the D.O content of sewage.

A. Winkler method
B. Chromatography
C. Kjeldahl method
D. Olfactometer
Answer» C. Kjeldahl method
63.

Which of the following disease is caused due to lack of nitrates?

A. Diphtheria
B. Methemoglobinemia
C. Tuberculosis
D. Meningitis
Answer» C. Tuberculosis
64.

Which of the following is an end product formed from both the aerobic and anaerobic decomposition of organic matter?

A. NO₃
B. CH₄
C. H₂S
D. CO₂
Answer» E.
65.

The aerobic decomposition of carbonaceous organic matter gives __________

A. Nitrites and water
B. Carbon dioxide and water
C. Sulfates and water
D. Nitrogen and Ammonia
Answer» C. Sulfates and water
66.

Identify the odd one of the following.

A. Fatty acids
B. Chlorides
C. Cellulose
D. Fats
Answer» C. Cellulose
67.

The fresh sewage is acidic in nature.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
68.

The maximum quantity of dissolved oxygen present in wastewater is called __________

A. Saturated dissolved oxygen
B. Maximum dissolved oxygen
C. Optimal dissolved oxygen
D. Peak dissolved oxygen
Answer» B. Maximum dissolved oxygen
69.

The oxygen deficit is maximum when?

A. Rate of reaeration is 0
B. Rate of deoxygenation is 0
C. Rate of reaeration equals the rate of deoxygenation
D. Rate of reaeration > rate of deoxygenation
Answer» D. Rate of reaeration > rate of deoxygenation
70.

Rate of aeration is independent of the D.O content of wastewater.

A. True
B. False
C. May be True or False
D. Can't Say
Answer» C. May be True or False
71.

What is yellow curve represents in the following figure?

A. Deoxygenation curve
B. Reoxygenation curve
C. Oxygen sag curve
D. Equilibrium concentration of oxygen
Answer» B. Reoxygenation curve
72.

The maximum deficiency of dissolved oxygen is represented by ____________

A. Dotted blue line
B. Green curve
C. Yellow curve
D. Violet curve
Answer» B. Green curve
73.

Which of the following is represented by the green curve in the following figure?

A. Deoxygenation curve
B. Reoxygenation curve
C. Oxygen sag curve
D. Equilibrium concentration of oxygen
Answer» C. Oxygen sag curve
74.

Which of the following is formed from the anaerobic oxidation of organic matter?

A. NO₃
B. SO₄
C. H₂S
D. NH₂
Answer» D. NH₂
75.

The lakes are classified into how many types on the basis of productivity?

A. 2
B. 3
C. 4
D. 6
Answer» D. 6
76.

The uppermost zone in lakes is called as ____________

A. Euphotic zone
B. Benthic zone
C. Littoral zone
D. Climate zone
Answer» B. Benthic zone
77.

_____ is the amount of oxygen required to oxidize only organic matter in sewage.

A. Turbidity
B. BOD
C. COD
D. DO
Answer» C. COD
78.

In which pollution zone of the river, growth of algae reappear?

A. Zone of degradation
B. Zone of recovery
C. Zone of active decomposition
D. Zone of clean water
Answer» C. Zone of active decomposition
79.

In which form of solute stabilization, hydrogen sulfide in the effluent is oxidized into sulfate?

A. Chlorination
B. Liming
C. Re-carbonation
D. Super-chlorination
Answer» B. Liming
80.

The fishes were present in the river, but algaes were not able to survive. What is the zone of pollution of the river?

A. Zone of recovery
B. Zone of degradation
C. Zone of clean water
D. Zone of active decomposition
Answer» C. Zone of clean water
81.

The detention period of detritus tank is ____________

A. 40 seconds
B. 1 minute
C. 3 minute
D. 1 hour
Answer» D. 1 hour
82.

Which of the following is measured in mg/L?

A. Unit weight
B. Coefficient of cohesion
C. Discharge
D. Turbidity
Answer» E.
83.

__________ is used to cut the sewage into smaller parts.

A. Flocculator
B. Tube settlers
C. Shredders
D. Aerators
Answer» D. Aerators
84.

The tolerance limit of COD of sewage to be discharged in sea water is ____________

A. 250ppm
B. 100ppm
C. 40ppm
D. 20ppm
Answer» B. 100ppm
85.

The depth of Euphotic zone is measured by ____________

A. Calorimeter
B. Turbidity meter
C. Secchi disk
D. Radar
Answer» D. Radar
86.

Which form of solute stabilization occurs when effluent passes through limestone?

A. Chlorination
B. Liming
C. Re-carbonation
D. Super-chlorination
Answer» C. Re-carbonation
87.

Which of the following has minimum detention period?

A. Grit chamber
B. Sedimentation tank
C. Oxidation ditch
D. Oxidation pond
Answer» B. Sedimentation tank
88.

Which of the following device is used for the removal of oil and grease?

A. Skimming tank
B. Grit chambers
C. Tube settlers
D. Flocculator
Answer» B. Grit chambers
89.

Which is the third zone of pollution in the river?

A. Zone of recovery
B. Zone of degradation
C. Zone of clean water
D. Zone of active decomposition
Answer» B. Zone of degradation
90.

When the BOD of wastewater increases, then?

A. Rate of reaeration decreases
B. Rate of oxygen deficit increases
C. Rate of oxygen deficit decreases
D. Amount of oxygen in wastewater increases
Answer» C. Rate of oxygen deficit decreases
91.

The nitrogenous demand begins after how many days?

A. 1
B. 2
C. 3
D. 5
Answer» E.
92.

Which of the following is formed due to the anaerobic decomposition of carbonaceous organic matter?

A. Nitrites
B. Carbon dioxide
C. Water
D. Nitrogen
Answer» C. Water
93.

BOD of wastewater having aerobic oxidation is more than that, having anaerobic oxidation.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
94.

Methane is formed due to the reduction of __________

A. Nitrates
B. Sulfates
C. Carbon dioxide
D. Organic acids
Answer» E.
95.

Which of the following is formed due to the reduction of sulfurous organic matter?

A. Hydrogen sulfide
B. Hydrochloric acid
C. Sulfuric acid
D. Sulfur dioxide
Answer» B. Hydrochloric acid
96.

Dealkalization results in removal of all the ions from the wastewater.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
97.

Which of the following represents the oxygen sag curve in the following figure?

A. Dotted blue line
B. Green curve
C. Yellow curve
D. Red curve
Answer» E.
98.

The minimum spacing between the bars on fine screen is ____________

A. 0.3mm
B. 0.9mm
C. 1.5mm
D. 0.5mm
Answer» D. 0.5mm
99.

The decomposition of nitrogenous organic matter in the absence of oxygen gives __________

A. Nitrites and water
B. Carbon dioxide and water
C. Nitrates and ammonia
D. Nitrogen, ammonia and organic acids
Answer» E.
100.

COD is abbreviated as ___________

A. Chemical oxygen demand
B. Complex oxygen demand
C. Customary oxygen demand
D. Chemical oxygen deficit
Answer» B. Complex oxygen demand