Environmental Engineering Exam
Questions and Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. Which parameter is most commonly used to measure the organic
strength of wastewater?
A. Total Dissolved Solids
B. Turbidity
C. Biochemical Oxygen Demand
D. Alkalinity
C. Biochemical Oxygen Demand
BOD measures the amount of oxygen required by microorganisms
to biologically degrade organic matter in wastewater.
2. The primary purpose of sedimentation in water treatment is to
remove:
A. Dissolved gases
B. Suspended solids
C. Pathogens
D. Hardness
B. Suspended solids
Sedimentation allows heavier suspended particles to settle by
gravity.
3. Which law governs the settling velocity of small spherical particles
in laminar flow?
A. Darcy’s Law
, B. Bernoulli’s Equation
C. Stokes’ Law
D. Fick’s Law
C. Stokes’ Law
Stokes’ Law calculates settling velocity for small particles under
laminar conditions.
4. The pH of pure water at 25°C is:
A. 5
B. 6
C. 7
D. 8
C. 7
Pure water at 25°C is neutral with a pH of 7.
5. In activated sludge systems, microorganisms are maintained in
suspension by:
A. Filtration
B. Aeration
C. Chlorination
D. Coagulation
B. Aeration
Aeration supplies oxygen and keeps biomass mixed.
6. The major greenhouse gas produced in landfills is:
A. Nitrous oxide
B. Carbon monoxide
C. Methane
D. Sulfur dioxide
C. Methane
Anaerobic decomposition of organic waste produces methane.
, 7. Which unit process is used primarily for pathogen inactivation?
A. Flocculation
B. Screening
C. Disinfection
D. Grit removal
C. Disinfection
Disinfection destroys or inactivates disease-causing organisms.
8. The hydraulic retention time (HRT) is defined as:
A. Flow divided by volume
B. Volume divided by flow
C. Depth divided by velocity
D. Area divided by discharge
B. Volume divided by flow
HRT represents the average time water remains in a reactor.
9. Which parameter indicates the clarity of water?
A. Turbidity
B. Conductivity
C. BOD
D. COD
A. Turbidity
Turbidity measures light scattering caused by suspended particles.
10. The main objective of primary wastewater treatment is to
remove:
A. Dissolved nutrients
B. Suspended solids
C. Heavy metals
D. Pathogens
B. Suspended solids
Primary treatment removes settleable and floatable solids.
Questions and Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A |
Instant Download Pdf
1. Which parameter is most commonly used to measure the organic
strength of wastewater?
A. Total Dissolved Solids
B. Turbidity
C. Biochemical Oxygen Demand
D. Alkalinity
C. Biochemical Oxygen Demand
BOD measures the amount of oxygen required by microorganisms
to biologically degrade organic matter in wastewater.
2. The primary purpose of sedimentation in water treatment is to
remove:
A. Dissolved gases
B. Suspended solids
C. Pathogens
D. Hardness
B. Suspended solids
Sedimentation allows heavier suspended particles to settle by
gravity.
3. Which law governs the settling velocity of small spherical particles
in laminar flow?
A. Darcy’s Law
, B. Bernoulli’s Equation
C. Stokes’ Law
D. Fick’s Law
C. Stokes’ Law
Stokes’ Law calculates settling velocity for small particles under
laminar conditions.
4. The pH of pure water at 25°C is:
A. 5
B. 6
C. 7
D. 8
C. 7
Pure water at 25°C is neutral with a pH of 7.
5. In activated sludge systems, microorganisms are maintained in
suspension by:
A. Filtration
B. Aeration
C. Chlorination
D. Coagulation
B. Aeration
Aeration supplies oxygen and keeps biomass mixed.
6. The major greenhouse gas produced in landfills is:
A. Nitrous oxide
B. Carbon monoxide
C. Methane
D. Sulfur dioxide
C. Methane
Anaerobic decomposition of organic waste produces methane.
, 7. Which unit process is used primarily for pathogen inactivation?
A. Flocculation
B. Screening
C. Disinfection
D. Grit removal
C. Disinfection
Disinfection destroys or inactivates disease-causing organisms.
8. The hydraulic retention time (HRT) is defined as:
A. Flow divided by volume
B. Volume divided by flow
C. Depth divided by velocity
D. Area divided by discharge
B. Volume divided by flow
HRT represents the average time water remains in a reactor.
9. Which parameter indicates the clarity of water?
A. Turbidity
B. Conductivity
C. BOD
D. COD
A. Turbidity
Turbidity measures light scattering caused by suspended particles.
10. The main objective of primary wastewater treatment is to
remove:
A. Dissolved nutrients
B. Suspended solids
C. Heavy metals
D. Pathogens
B. Suspended solids
Primary treatment removes settleable and floatable solids.
