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Manitoba Wastewater Treatment Operator Class I Practice Exam Questions And ( Answers) Plus Rationales 2026 Q&A Instant Download Pdf
- What is the primary purpose of wastewater treatment?
- To increase water hardness
- To remove dissolved oxygen
- To protect public health and the environment
- To produce drinking water
Correct Answer: C
Rationale: Wastewater treatment primarily aims to remove contaminants
to protect human health and the environment.
2. Preliminary treatment mainly removes: 1 / 4
- Nutrients
- Grit and large solids
- Dissolved organics
- Pathogens
Correct Answer: B
Rationale: Preliminary treatment removes large debris and grit to protect
downstream equipment.
3. BOD stands for:
- Biological Oxidation Demand
- Basic Oxygen Demand
- Biochemical Oxygen Demand
- Bio-Oxygen Dilution
Correct Answer: C
Rationale: BOD measures the amount of oxygen microorganisms need to
degrade organic matter.
4. High BOD in wastewater indicates:
- High dissolved solids
- High oxygen content
- High organic pollution
- Low microbial activity 2 / 4
Correct Answer: C
Rationale: BOD rises as organic pollution increases.
5. Grit chambers remove particles with:
- Low settling velocity
- High settling velocity
- Neutral buoyancy
- Pathogenic potential
Correct Answer: B
Rationale: Grit particles like sand settle quickly due to high density.
6. Clarifiers rely primarily on:
- Absorption
- Filtration
- Sedimentation
- Aeration
Correct Answer: C
Rationale: Clarifiers settle solids using gravity.
- The activated sludge process is an example of: 3 / 4
- Physical treatment
- Chemical treatment
- Biological treatment
- Thermal treatment
Correct Answer: C
Rationale: Activated sludge uses microorganisms to break down organics.
8. In aeration tanks, dissolved oxygen should typically be:
- 0–0.5 mg/L
- 1–2 mg/L
- 2–4 mg/L
- 8–10 mg/L
Correct Answer: C
Rationale: 2–4 mg/L supports optimal microbial activity.
9. Sludge age refers to:
- Sludge pH
- Time solids remain in the system
- Temperature of sludge
- Weight of solids removed
Correct Answer: B
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