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.

1.

Which of the following is formed from oxidation of organic matter in the presence of oxygen?

A. NO₃
B. SO₄
C. H₂S
D. NH₂
Answer» B. SO₄
2.

______ zone lies between Euphotic and Benthic zone.

A. Euphotic zone
B. Benthic zone
C. Littoral zone
D. Climate zone
Answer» D. Climate zone
3.

What is the value of BOD of industrial sewage in kg/day, given population equivalent as 6000 persons?

A. 480
B. 160
C. 270
D. 100
Answer» B. 160
4.

Which one of the following lakes has minimum productivity?

A. Mesotrophic lake
B. Senescent lake
C. Oligotrophic lake
D. Eutrophic lake
Answer» D. Eutrophic lake
5.

________ is the process of acceleration of eutrophication due to increased phosphorous content in lakes.

A. Photosynthesis
B. Chemical eutrophication
C. Cultural eutrophication
D. Custom eutrophication
Answer» D. Custom eutrophication
6.

_______ is the process of overgrowth of plants and algae in lakes.

A. Transpiration
B. Reproduction
C. Eutrophication
D. Photosynthesis
Answer» D. Photosynthesis
7.

The expression of relative stability at 37°C is given by ___________

A. S = (1-(0.794)ᵀ³⁷)
B. S = 100 (1-(0.794)ᵀ³⁷)
C. S = 1-(0.794)ᵀ²⁰
D. S = 100 (1-(0.630)ᵀ³⁷)
Answer» E.
8.

Which of the following process is used to remove the colloidal particles from the effluent?

A. Chemical precipitation
B. Chemical coagulation
C. Ion exchange
D. Adsorption
Answer» C. Ion exchange
9.

In which unit operation, gases are released or absorbed in the effluent?

A. Gas transfer
B. Ion transfer
C. Solute stabilization
D. Solids Transfer
Answer» B. Ion transfer
10.

Which of the following id the correct expression of population equivalent?

A. BOD of industrial sewage in kg/day * 0.08
B. 0.08 * BOD of industrial sewage kg/day
C. BOD of industrial sewage kg/day / 0.08kg/person/day
D. BOD of industrial sewage kg/day + 0.08
Answer» D. BOD of industrial sewage kg/day + 0.08
11.

Solids are removed from the wastewater by which of the following unit operation?

A. Inter facial contact
B. Solid stabilization
C. Ion transfer
D. Solids transfer
Answer» E.
12.

The dimension formula of dynamic viscosity is ____________

A. ML⁻¹T
B. ML⁻¹T⁻¹
C. ML⁻²T⁻²
D. ML⁻¹T⁻³
Answer» C. ML⁻²T⁻²
13.

The head loss through the screen is given by HL = k* (Vₜ² – Vₐ²), where Vₜ and Vₐ are velocities through and above the screen respectively. What is the value of constant k?

A. 1
B. 0.0050
C. 0.0729
D. 0.0236
Answer» D. 0.0236
14.

The dilution factor is 400. What should be the type of treatment given to the water?

A. Preliminary treatment
B. Sedimentation, Flocculation
C. Complete treatment
D. No treatment
Answer» B. Sedimentation, Flocculation
15.

Organic contaminants are removed from the wastewater by ____________

A. Water softening
B. Demineralization
C. Absorption
D. Adsorption
Answer» E.
16.

By which process, odor producing substances are oxidized?

A. Chlorination
B. Liming
C. Re-carbonation
D. Super-chlorination
Answer» E.
17.

The pollution zones in the river are divided into how many types?

A. 3
B. 4
C. 6
D. 8
Answer» C. 6
18.

5 days BOD at 20°C is ___ of total demand.

A. 20%
B. 47%
C. 68%
D. 100%
Answer» D. 100%
19.

In which zone, decomposition of the dead organism takes place?

A. Climate zone
B. Benthic zone
C. Littoral zone
D. Euphotic zone
Answer» C. Littoral zone
20.

The minimum depth to which sewage should be discharged of sea water is ____________

A. 0.5m
B. 1m
C. 2m
D. 3m
Answer» E.
21.

In which of the following, large impurities are attached with air bubbles to remove it from the wastewater?

A. Sludge digestion tank
B. Primary sedimentation
C. Vacuum floatation
D. Oxidation pond
Answer» D. Oxidation pond
22.

Calculate the percentage of relative stability, given 5 day incubation period at 37°C.

A. 50%
B. 60%
C. 90%
D. 99%
Answer» D. 99%
23.

The turbulence decreases the DO content of water.

A. True
B. False
C. May be True or False
D. Can't say
Answer» C. May be True or False
24.

Partially oxidized sewage contains __________

A. Nitrites and Nitrates
B. Nitrates and sulfur
C. Sulfates and nitrates
D. Nitrites and sulfur
Answer» E.
25.

Which of the following expression is correct regarding deoxygenation constant where symbols have their usual meaning?

A. KDT = KD20 + (1.047)ᵀ⁻²⁰
B. KDT = KD20 / (1.047)ᵀ⁻²⁰
C. KDT = KD20 (1.047)ᵀ⁻²⁰
D. KDT = KD20 (1.04ᵀ)
Answer» D. KDT = KD20 (1.04ᵀ)
26.

The maximum spacing between the bars in medium screen is ____________

A. 40mm
B. 50mm
C. 70mm
D. 90mm
Answer» B. 50mm
27.

In which pollution zone of the river, water retains its original dissolved oxygen concentration?

A. Zone of degradation
B. Zone of recovery
C. Zone of active decomposition
D. Zone of clean water
Answer» E.
28.

The unit of dynamic viscosity is ____________

A. Metre²/Sec
B. Metre/Sec
C. Pa * Sec
D. Dimensionless
Answer» D. Dimensionless
29.

Which of the following is a prime lake pollutant?

A. Iodine
B. Phosphorous
C. Potassium
D. Sodium
Answer» C. Potassium
30.

The tolerance limit of pH value of sewage to be discharged into sea water is ____________

A. 1-5ppm
B. 2-9ppm
C. 5.5-9ppm
D. 6-10ppm
Answer» D. 6-10ppm
31.

Which type of pollution is Cultural eutrophication?

A. Water pollution
B. Noise pollution
C. Thermal pollution
D. Soil pollution
Answer» B. Noise pollution
32.

The tolerance limit of oil and grease of sewage to be disposed on land is ____________

A. 40ppm
B. 30ppm
C. 20ppm
D. 10ppm
Answer» C. 20ppm
33.

The coefficient of drag for a transition settling is ____________

A. CD = 18.5/R⁰·⁶
B. CD = 24/R
C. CD = 8.5/R⁰·⁶
D. CD = R/24
Answer» B. CD = 24/R
34.

Screens are inclined to the direction of flow to ____________

A. Increase the flow velocity
B. Increase the opening area
C. Decrease the flow velocity
D. Increase the head loss
Answer» D. Increase the head loss
35.

How many types of aerators are commonly used in the treatment of wastewater?

A. 2
B. 3
C. 4
D. 5
Answer» D. 5
36.

In which pollution zone of the river, the dissolved oxygen reduced to 0?

A. Zone of degradation
B. Zone of recovery
C. Zone of clean water
D. Zone of active decomposition
Answer» E.
37.

The dilution factor is expressed by _____________

A. Volume of diluted sample + Volume of sewage
B. Volume of diluted sample / Volume of sewage
C. Volume of diluted sample – Volume of sewage
D. Volume of diluted sample* Volume of sewage
Answer» C. Volume of diluted sample – Volume of sewage
38.

The aerobic decomposition of sulfurous organic matter gives __________

A. Nitrites and water
B. Carbon dioxide and water
C. Sulfates and water
D. Nitrogen and Ammonia
Answer» D. Nitrogen and Ammonia
39.

Which chemical is used for the titration of waste water for finding its chloride content?

A. Potassium chloride
B. Sodium chloride
C. Potassium chromate
D. Potassium dichromate
Answer» D. Potassium dichromate
40.

The type of solids which floats in sewage is __________

A. Suspended solids
B. Settleable solids
C. Dissolved solids
D. Total solids
Answer» B. Settleable solids
41.

The presence of which of the following in sewage indicates nitrogen content before decomposition of sewage?

A. Nitrites
B. Nitrates
C. Free ammonia
D. Albuminoid nitrogen
Answer» E.
42.

The presence of free ammonia in sewage represents ____________

A. Air pollution
B. Old pollution
C. Recent pollution
D. Water pollution
Answer» D. Water pollution
43.

The presence of which of the following indicates old pollution?

A. Nitrates
B. Nitrites
C. H₂S
D. Sulfates
Answer» E.
44.

The odor quality of compound is ammoniacal. Identify the type of compound from the following options.

A. Acetic acid
B. Benzene
C. Ammonia
D. Methane
Answer» D. Methane
45.

The wastewater from the kitchen is an example of __________

A. Black water
B. Yellow water
C. Green water
D. Grey water
Answer» E.
46.

The type of wastewater from the flushing operation of toilet is __________

A. Green water
B. Red water
C. Black water
D. Brown water
Answer» D. Brown water
47.

The temperature of sewage increases. What will be the effect on the dissolved oxygen in sewage?

A. Remains constant
B. Increase
C. Decrease
D. No effect
Answer» D. No effect
48.

What is the minimum quantity of dissolved oxygen that should be present in the treated sewage?

A. 6ppm
B. 4ppm
C. 1ppm
D. 10ppm
Answer» C. 1ppm
49.

_______ indicates the freshness of sewage.

A. Turbidity
B. Color
C. Temperature
D. COD
Answer» C. Temperature
50.

Identify the incorrect statement from the following?

A. High odor intensity indicates odorless water
B. Fresh sewage is odorless
C. Turbidity can be measured by turbidity rod
D. NTU is a unit of turbidity
Answer» B. Fresh sewage is odorless