ALBERTA WASTEWATER TREATMENT OPERATOR LEVEL
1 EXAMINATION COMPLETE QUESTIONS AND DETAILED
SOLUTIONS LATEST UPDATE THIS YEAR JUST RELEASED
Coverage Areas
1. Wastewater Characteristics — domestic wastewater composition, solids, organics, nutrients, and indicators.
2. Preliminary Treatment — screening, grit removal, comminution, and influent flow measurement.
3. Primary Treatment — sedimentation, detention time, sludge collection, and scum removal.
4. Secondary Biological Treatment — microorganisms, dissolved oxygen, aeration, activated sludge, and process
control.
5. Secondary Clarification — settling, return activated sludge, waste activated sludge, and solids separation.
6. Disinfection — chlorine, UV, contact time, residuals, and pathogen control.
7. Solids Handling — sludge thickening, digestion, dewatering, storage, and disposal.
8. Laboratory Testing & Process Monitoring — BOD, TSS, pH, DO, ammonia, sampling, and records.
9. Pumps, Equipment & Instrumentation — centrifugal pumps, valves, blowers, meters, alarms, and maintenance.
10. Safety, Environment & Operator Responsibilities — confined spaces, chemical hazards, PPE, regulatory compliance,
environmental protection, and emergency response.
1. Which wastewater characteristic most directly represents the amount of
biodegradable organic material that microorganisms can consume during
treatment?
A. Total alkalinity
B. Biochemical oxygen demand
C. Chloride concentration
D. Settleable inorganic solids
Answer: B. Biochemical oxygen demand
Rationale: BOD estimates the oxygen required by microorganisms to
biologically stabilize biodegradable organic matter in wastewater. Higher
BOD generally indicates a greater organic treatment load.
2. Why is preliminary screening normally performed before wastewater
enters pumps and downstream treatment processes at a municipal
facility?
,A. To increase wastewater temperature
B. To remove dissolved ammonia
C. To protect equipment from large debris
D. To disinfect wastewater completely
Answer: C. To protect equipment from large debris
Rationale: Screens remove rags, plastics, sticks, and other large materials
that could clog pumps, damage equipment, or interfere with subsequent
treatment processes.
3. What is the primary purpose of a grit removal process in a conventional
wastewater treatment facility?
A. Remove dissolved oxygen
B. Remove heavy inorganic particles
C. Increase biological oxygen demand
D. Destroy pathogenic microorganisms
Answer: B. Remove heavy inorganic particles
Rationale: Grit systems remove dense inorganic materials such as sand,
gravel, eggshell fragments, and other particles that can accumulate in
channels, tanks, and mechanical equipment.
4. During wastewater treatment, which measurement provides an
operator with the most direct indication of oxygen available for aerobic
microorganisms?
A. Dissolved oxygen
B. Total suspended solids
,C. Chloride
D. Conductivity
Answer: A. Dissolved oxygen
Rationale: Dissolved oxygen, or DO, indicates the oxygen available in water
for aerobic biological activity. Operators monitor DO to help maintain
appropriate biological treatment conditions.
5. Why must an operator monitor dissolved oxygen carefully in an
activated sludge aeration basin during normal operation?
A. Excessive or insufficient oxygen can affect biological treatment
performance
B. DO directly measures chlorine concentration
C. DO determines the amount of grit entering the facility
D. DO measures the depth of primary sludge
Answer: A. Excessive or insufficient oxygen can affect biological treatment
performance
Rationale: Aerobic microorganisms require oxygen, but excessively high DO
can waste aeration energy. Insufficient DO can impair treatment and cause
undesirable biological conditions.
6. Which wastewater treatment process primarily removes suspended
solids through gravity settling before biological treatment?
A. Primary clarification
B. Ultraviolet disinfection
C. Aerobic digestion
D. Chemical oxidation
, Answer: A. Primary clarification
Rationale: Primary clarifiers allow heavier suspended solids to settle while
lighter materials float and can be removed as scum.
7. What happens to most settleable solids entering a properly functioning
primary clarifier?
A. They are converted immediately into dissolved gases
B. They settle toward the bottom of the tank
C. They are disinfected by ultraviolet radiation
D. They are returned directly to the aeration basin
Answer: B. They settle toward the bottom of the tank
Rationale: Gravity causes settleable solids to move downward, where
mechanical or hydraulic sludge collection systems transport the
accumulated primary sludge for further processing.
8. Which condition would most likely indicate that a wastewater screen
requires immediate operator attention?
A. Normal screening with expected debris accumulation
B. Increasing upstream water level caused by screen blockage
C. Stable downstream flow
D. Normal pump amperage
Answer: B. Increasing upstream water level caused by screen blockage
Rationale: A blocked or overloaded screen can restrict flow, causing
upstream levels to rise and potentially leading to bypassing, flooding, or
equipment problems.
1 EXAMINATION COMPLETE QUESTIONS AND DETAILED
SOLUTIONS LATEST UPDATE THIS YEAR JUST RELEASED
Coverage Areas
1. Wastewater Characteristics — domestic wastewater composition, solids, organics, nutrients, and indicators.
2. Preliminary Treatment — screening, grit removal, comminution, and influent flow measurement.
3. Primary Treatment — sedimentation, detention time, sludge collection, and scum removal.
4. Secondary Biological Treatment — microorganisms, dissolved oxygen, aeration, activated sludge, and process
control.
5. Secondary Clarification — settling, return activated sludge, waste activated sludge, and solids separation.
6. Disinfection — chlorine, UV, contact time, residuals, and pathogen control.
7. Solids Handling — sludge thickening, digestion, dewatering, storage, and disposal.
8. Laboratory Testing & Process Monitoring — BOD, TSS, pH, DO, ammonia, sampling, and records.
9. Pumps, Equipment & Instrumentation — centrifugal pumps, valves, blowers, meters, alarms, and maintenance.
10. Safety, Environment & Operator Responsibilities — confined spaces, chemical hazards, PPE, regulatory compliance,
environmental protection, and emergency response.
1. Which wastewater characteristic most directly represents the amount of
biodegradable organic material that microorganisms can consume during
treatment?
A. Total alkalinity
B. Biochemical oxygen demand
C. Chloride concentration
D. Settleable inorganic solids
Answer: B. Biochemical oxygen demand
Rationale: BOD estimates the oxygen required by microorganisms to
biologically stabilize biodegradable organic matter in wastewater. Higher
BOD generally indicates a greater organic treatment load.
2. Why is preliminary screening normally performed before wastewater
enters pumps and downstream treatment processes at a municipal
facility?
,A. To increase wastewater temperature
B. To remove dissolved ammonia
C. To protect equipment from large debris
D. To disinfect wastewater completely
Answer: C. To protect equipment from large debris
Rationale: Screens remove rags, plastics, sticks, and other large materials
that could clog pumps, damage equipment, or interfere with subsequent
treatment processes.
3. What is the primary purpose of a grit removal process in a conventional
wastewater treatment facility?
A. Remove dissolved oxygen
B. Remove heavy inorganic particles
C. Increase biological oxygen demand
D. Destroy pathogenic microorganisms
Answer: B. Remove heavy inorganic particles
Rationale: Grit systems remove dense inorganic materials such as sand,
gravel, eggshell fragments, and other particles that can accumulate in
channels, tanks, and mechanical equipment.
4. During wastewater treatment, which measurement provides an
operator with the most direct indication of oxygen available for aerobic
microorganisms?
A. Dissolved oxygen
B. Total suspended solids
,C. Chloride
D. Conductivity
Answer: A. Dissolved oxygen
Rationale: Dissolved oxygen, or DO, indicates the oxygen available in water
for aerobic biological activity. Operators monitor DO to help maintain
appropriate biological treatment conditions.
5. Why must an operator monitor dissolved oxygen carefully in an
activated sludge aeration basin during normal operation?
A. Excessive or insufficient oxygen can affect biological treatment
performance
B. DO directly measures chlorine concentration
C. DO determines the amount of grit entering the facility
D. DO measures the depth of primary sludge
Answer: A. Excessive or insufficient oxygen can affect biological treatment
performance
Rationale: Aerobic microorganisms require oxygen, but excessively high DO
can waste aeration energy. Insufficient DO can impair treatment and cause
undesirable biological conditions.
6. Which wastewater treatment process primarily removes suspended
solids through gravity settling before biological treatment?
A. Primary clarification
B. Ultraviolet disinfection
C. Aerobic digestion
D. Chemical oxidation
, Answer: A. Primary clarification
Rationale: Primary clarifiers allow heavier suspended solids to settle while
lighter materials float and can be removed as scum.
7. What happens to most settleable solids entering a properly functioning
primary clarifier?
A. They are converted immediately into dissolved gases
B. They settle toward the bottom of the tank
C. They are disinfected by ultraviolet radiation
D. They are returned directly to the aeration basin
Answer: B. They settle toward the bottom of the tank
Rationale: Gravity causes settleable solids to move downward, where
mechanical or hydraulic sludge collection systems transport the
accumulated primary sludge for further processing.
8. Which condition would most likely indicate that a wastewater screen
requires immediate operator attention?
A. Normal screening with expected debris accumulation
B. Increasing upstream water level caused by screen blockage
C. Stable downstream flow
D. Normal pump amperage
Answer: B. Increasing upstream water level caused by screen blockage
Rationale: A blocked or overloaded screen can restrict flow, causing
upstream levels to rise and potentially leading to bypassing, flooding, or
equipment problems.
