Level I Practice Exam Questions And

Saskatchewan Wastewater Operator Level I Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• 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.

• Which of the following is a typical component of primary treatment?

a) Chlorination 1 / 4

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.

• 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 2 / 4

c) Biological Organic Dissolution

d) Base Oxygen Determination

Rationale: BOD measures the amount of oxygen microorganisms

consume to decompose organic matter.

• 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.

• 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).

• What is the main purpose of a grit chamber?

a) Remove oils

b) Remove organic matter 3 / 4

c) Remove sand, gravel, and heavy inorganic particles

d) Disinfect wastewater

Rationale: Grit chambers remove heavy inorganic particles to

prevent damage to downstream equipment.

• 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.

• Which chemical is commonly used for coagulation in wastewater

treatment?

a) Sodium hydroxide

b) Calcium carbonate

• / 4