ALBERTA WASTE WATER TREATMENT OPERATOR
CONTINUING COMPETENCY EXAM QUESTIONS
WITH CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A |INSTANT
DOWNLOAD PDF
1. What is the primary purpose of preliminary treatment in a
wastewater plant?
A. To remove dissolved nutrients
B. To neutralize pH
C. To remove large solids and debris
D. To disinfect pathogens
Rationale: Preliminary treatment protects downstream
equipment by removing rags, sticks, grit, and large solids.
2. Grit chambers are designed to remove which of the
following?
A. Floating grease
B. Organic sludge
C. Inorganic heavy particles like sand and gravel
D. Dissolved metals
Rationale: Grit removal prevents abrasion and settling
problems in later stages.
,3. Which of the following is the main biological process in
activated sludge treatment?
A. Coagulation
B. Aerobic decomposition of organic matter
C. Chlorination
D. Sedimentation
Rationale: Microorganisms biologically oxidize organic waste in
the presence of oxygen.
4. In wastewater terminology, BOD stands for:
A. Biological Oxidation Demand
B. Basic Organic Decomposition
C. Biochemical Oxygen Demand
D. Bacterial Oxidation Declaration
Rationale: BOD measures oxygen required by bacteria to
decompose organic matter.
5. Which factor most influences settling velocity in a clarifier?
A. Water color
B. Influent pH
C. Particle size and density
D. Temperature alone
Rationale: Larger and denser particles settle faster.
,6. What is the typical purpose of secondary clarification?
A. To disinfect wastewater
B. To add chemicals
C. To separate biomass from treated water
D. To adjust pH
Rationale: Clarifiers remove suspended solids and return active
biomass.
7. What parameter measures the strength of organic waste in
wastewater?
A. TSS
B. BOD
C. pH
D. Conductivity
Rationale: BOD quantifies biodegradable organic pollution load.
8. pH control in wastewater is important because:
A. It affects taste
B. It only affects color
C. It influences chemical reactions and microbial activity
D. It is not relevant
Rationale: Extreme pH can inhibit biological processes and
damage infrastructure.
, 9. TSS in wastewater refers to:
A. Total Suspended Solids
B. Total Soluble Substances
C. Total Suspended Solids
D. Total Soft Solutes
Rationale: TSS is solids retained on a filter.
10. What does the term “MLSS” refer to in activated sludge
systems?
A. Multiple Linear Solid System
B. Mixed Liquor Suspended Solids
C. Micro-Level Suspended Solids
D. Main Liquid Sludge Solution
Rationale: MLSS indicates concentration of biomass in aeration.
11. A sudden drop in dissolved oxygen in aeration tanks is
most likely caused by:
A. Increased influent flow
B. Reduced aeration capacity
C. High organic load
D. Lower temperature
Rationale: A spike in organic load increases oxygen demand.
CONTINUING COMPETENCY EXAM QUESTIONS
WITH CORRECT ANSWERS (VERIFIED ANSWERS)
PLUS RATIONALES 2026 Q&A |INSTANT
DOWNLOAD PDF
1. What is the primary purpose of preliminary treatment in a
wastewater plant?
A. To remove dissolved nutrients
B. To neutralize pH
C. To remove large solids and debris
D. To disinfect pathogens
Rationale: Preliminary treatment protects downstream
equipment by removing rags, sticks, grit, and large solids.
2. Grit chambers are designed to remove which of the
following?
A. Floating grease
B. Organic sludge
C. Inorganic heavy particles like sand and gravel
D. Dissolved metals
Rationale: Grit removal prevents abrasion and settling
problems in later stages.
,3. Which of the following is the main biological process in
activated sludge treatment?
A. Coagulation
B. Aerobic decomposition of organic matter
C. Chlorination
D. Sedimentation
Rationale: Microorganisms biologically oxidize organic waste in
the presence of oxygen.
4. In wastewater terminology, BOD stands for:
A. Biological Oxidation Demand
B. Basic Organic Decomposition
C. Biochemical Oxygen Demand
D. Bacterial Oxidation Declaration
Rationale: BOD measures oxygen required by bacteria to
decompose organic matter.
5. Which factor most influences settling velocity in a clarifier?
A. Water color
B. Influent pH
C. Particle size and density
D. Temperature alone
Rationale: Larger and denser particles settle faster.
,6. What is the typical purpose of secondary clarification?
A. To disinfect wastewater
B. To add chemicals
C. To separate biomass from treated water
D. To adjust pH
Rationale: Clarifiers remove suspended solids and return active
biomass.
7. What parameter measures the strength of organic waste in
wastewater?
A. TSS
B. BOD
C. pH
D. Conductivity
Rationale: BOD quantifies biodegradable organic pollution load.
8. pH control in wastewater is important because:
A. It affects taste
B. It only affects color
C. It influences chemical reactions and microbial activity
D. It is not relevant
Rationale: Extreme pH can inhibit biological processes and
damage infrastructure.
, 9. TSS in wastewater refers to:
A. Total Suspended Solids
B. Total Soluble Substances
C. Total Suspended Solids
D. Total Soft Solutes
Rationale: TSS is solids retained on a filter.
10. What does the term “MLSS” refer to in activated sludge
systems?
A. Multiple Linear Solid System
B. Mixed Liquor Suspended Solids
C. Micro-Level Suspended Solids
D. Main Liquid Sludge Solution
Rationale: MLSS indicates concentration of biomass in aeration.
11. A sudden drop in dissolved oxygen in aeration tanks is
most likely caused by:
A. Increased influent flow
B. Reduced aeration capacity
C. High organic load
D. Lower temperature
Rationale: A spike in organic load increases oxygen demand.
