Wastewater III Study Exam Questions
and Answers | Latest Version |
2025/2026 | Correct & Verified
What is the purpose of disinfection in wastewater treatment?
✔✔To kill or inactivate pathogenic microorganisms before discharge.
Why is chlorine commonly used for disinfection?
✔✔It is effective, easy to apply, and maintains residual in the effluent.
What is the function of an aerated lagoon?
✔✔To treat wastewater biologically with natural or mechanical aeration.
Why is nitrification important in wastewater treatment?
✔✔To convert ammonia into nitrate, reducing toxicity to aquatic life.
What is the purpose of denitrification in wastewater treatment?
✔✔To convert nitrates into nitrogen gas, reducing nutrient pollution.
1
,Why must pH be monitored in wastewater treatment?
✔✔Because extreme pH can harm biological treatment and affect chemical processes.
What is the purpose of a bar screen in preliminary treatment?
✔✔To remove large floating solids and debris.
Why is equalization important in wastewater plants?
✔✔To balance flow and pollutant concentrations for consistent treatment.
What is the purpose of a trickling filter?
✔✔To allow wastewater to flow over a biofilm for biological treatment.
Why is dissolved oxygen measured in aeration tanks?
✔✔To ensure sufficient oxygen for aerobic microorganisms.
What is the function of a return activated sludge (RAS) system?
✔✔To recycle microorganisms back to the aeration tank for continued treatment.
2
, Why is sludge digestion performed?
✔✔To stabilize organic matter and reduce pathogens before disposal.
Why is primary sedimentation important?
✔✔To remove settleable solids and reduce the organic load.
What does BOD measure in wastewater?
✔✔The amount of oxygen required by microorganisms to decompose organic matter.
Why is aeration used in secondary treatment?
✔✔To provide oxygen for biological treatment by microorganisms.
What is the purpose of clarifiers in secondary treatment?
✔✔To separate biological flocs from treated water.
Why is sludge removed from the bottom of clarifiers?
✔✔To prevent accumulation and maintain treatment efficiency.
3
and Answers | Latest Version |
2025/2026 | Correct & Verified
What is the purpose of disinfection in wastewater treatment?
✔✔To kill or inactivate pathogenic microorganisms before discharge.
Why is chlorine commonly used for disinfection?
✔✔It is effective, easy to apply, and maintains residual in the effluent.
What is the function of an aerated lagoon?
✔✔To treat wastewater biologically with natural or mechanical aeration.
Why is nitrification important in wastewater treatment?
✔✔To convert ammonia into nitrate, reducing toxicity to aquatic life.
What is the purpose of denitrification in wastewater treatment?
✔✔To convert nitrates into nitrogen gas, reducing nutrient pollution.
1
,Why must pH be monitored in wastewater treatment?
✔✔Because extreme pH can harm biological treatment and affect chemical processes.
What is the purpose of a bar screen in preliminary treatment?
✔✔To remove large floating solids and debris.
Why is equalization important in wastewater plants?
✔✔To balance flow and pollutant concentrations for consistent treatment.
What is the purpose of a trickling filter?
✔✔To allow wastewater to flow over a biofilm for biological treatment.
Why is dissolved oxygen measured in aeration tanks?
✔✔To ensure sufficient oxygen for aerobic microorganisms.
What is the function of a return activated sludge (RAS) system?
✔✔To recycle microorganisms back to the aeration tank for continued treatment.
2
, Why is sludge digestion performed?
✔✔To stabilize organic matter and reduce pathogens before disposal.
Why is primary sedimentation important?
✔✔To remove settleable solids and reduce the organic load.
What does BOD measure in wastewater?
✔✔The amount of oxygen required by microorganisms to decompose organic matter.
Why is aeration used in secondary treatment?
✔✔To provide oxygen for biological treatment by microorganisms.
What is the purpose of clarifiers in secondary treatment?
✔✔To separate biological flocs from treated water.
Why is sludge removed from the bottom of clarifiers?
✔✔To prevent accumulation and maintain treatment efficiency.
3
