Saskatchewan Wastewater Operator
Level I Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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1. What is the primary purpose of a wastewater treatment plant?
a) Produce drinking water
b) Generate electricity
c) Remove contaminants from wastewater before discharge
d) Increase water temperature
Rationale: The main goal of a wastewater treatment plant is to
remove pollutants from wastewater to protect public health and the
environment.
2. Which of the following is a typical component of primary treatment?
a) Chlorination
, b) Activated sludge
c) Sedimentation
d) Trickling filter
Rationale: Primary treatment mainly involves the physical removal of
solids through sedimentation.
3. Biological treatment in wastewater treatment primarily removes:
a) Heavy metals
b) Organic matter
c) Sand and grit
d) Chlorine
Rationale: Biological treatment uses microorganisms to break down
organic pollutants in wastewater.
4. Which microorganism is most commonly responsible for organic
matter decomposition in activated sludge systems?
a) Algae
b) Protozoa
c) Bacteria
d) Fungi
Rationale: Bacteria are the primary agents that metabolize organic
matter in activated sludge systems.
5. The term BOD stands for:
a) Basic Oxygen Demand
b) Biochemical Oxygen Demand
, c) Biological Organic Dissolution
d) Base Oxygen Determination
Rationale: BOD measures the amount of oxygen microorganisms
consume to decompose organic matter.
6. Why is dissolved oxygen important in aerobic wastewater treatment?
a) Prevents corrosion
b) Supports aerobic microorganisms in breaking down organic matter
c) Neutralizes pH
d) Reduces heavy metals
Rationale: Aerobic microorganisms require dissolved oxygen to
metabolize organic pollutants.
7. Which process is commonly used to remove nitrogen from
wastewater?
a) Filtration
b) Sedimentation
c) Nitrification/Denitrification
d) Coagulation
Rationale: Nitrogen removal involves biological processes where
ammonia is converted to nitrate (nitrification) and then to nitrogen
gas (denitrification).
8. What is the main purpose of a grit chamber?
a) Remove oils
b) Remove organic matter
, c) Remove sand, gravel, and heavy inorganic particles
d) Disinfect wastewater
Rationale: Grit chambers remove heavy inorganic particles to
prevent damage to downstream equipment.
9. Which unit process is primarily used to disinfect wastewater before
discharge?
a) Aeration
b) Sedimentation
c) Chlorination or UV treatment
d) Flocculation
Rationale: Disinfection processes such as chlorination or UV
treatment destroy pathogenic microorganisms in effluent.
10. Sludge digestion is mainly used to:
a) Remove sand
b) Stabilize organic matter and reduce pathogens
c) Increase flow rate
d) Adjust pH
Rationale: Anaerobic or aerobic digestion stabilizes sludge, reduces
odors, and minimizes pathogens.
11. Which chemical is commonly used for coagulation in wastewater
treatment?
a) Sodium hydroxide
b) Calcium carbonate
Level I Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of a wastewater treatment plant?
a) Produce drinking water
b) Generate electricity
c) Remove contaminants from wastewater before discharge
d) Increase water temperature
Rationale: The main goal of a wastewater treatment plant is to
remove pollutants from wastewater to protect public health and the
environment.
2. Which of the following is a typical component of primary treatment?
a) Chlorination
, b) Activated sludge
c) Sedimentation
d) Trickling filter
Rationale: Primary treatment mainly involves the physical removal of
solids through sedimentation.
3. Biological treatment in wastewater treatment primarily removes:
a) Heavy metals
b) Organic matter
c) Sand and grit
d) Chlorine
Rationale: Biological treatment uses microorganisms to break down
organic pollutants in wastewater.
4. Which microorganism is most commonly responsible for organic
matter decomposition in activated sludge systems?
a) Algae
b) Protozoa
c) Bacteria
d) Fungi
Rationale: Bacteria are the primary agents that metabolize organic
matter in activated sludge systems.
5. The term BOD stands for:
a) Basic Oxygen Demand
b) Biochemical Oxygen Demand
, c) Biological Organic Dissolution
d) Base Oxygen Determination
Rationale: BOD measures the amount of oxygen microorganisms
consume to decompose organic matter.
6. Why is dissolved oxygen important in aerobic wastewater treatment?
a) Prevents corrosion
b) Supports aerobic microorganisms in breaking down organic matter
c) Neutralizes pH
d) Reduces heavy metals
Rationale: Aerobic microorganisms require dissolved oxygen to
metabolize organic pollutants.
7. Which process is commonly used to remove nitrogen from
wastewater?
a) Filtration
b) Sedimentation
c) Nitrification/Denitrification
d) Coagulation
Rationale: Nitrogen removal involves biological processes where
ammonia is converted to nitrate (nitrification) and then to nitrogen
gas (denitrification).
8. What is the main purpose of a grit chamber?
a) Remove oils
b) Remove organic matter
, c) Remove sand, gravel, and heavy inorganic particles
d) Disinfect wastewater
Rationale: Grit chambers remove heavy inorganic particles to
prevent damage to downstream equipment.
9. Which unit process is primarily used to disinfect wastewater before
discharge?
a) Aeration
b) Sedimentation
c) Chlorination or UV treatment
d) Flocculation
Rationale: Disinfection processes such as chlorination or UV
treatment destroy pathogenic microorganisms in effluent.
10. Sludge digestion is mainly used to:
a) Remove sand
b) Stabilize organic matter and reduce pathogens
c) Increase flow rate
d) Adjust pH
Rationale: Anaerobic or aerobic digestion stabilizes sludge, reduces
odors, and minimizes pathogens.
11. Which chemical is commonly used for coagulation in wastewater
treatment?
a) Sodium hydroxide
b) Calcium carbonate
