Alberta Wastewater Treatment Operator
Level 1 Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download
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1. What is the primary purpose of wastewater treatment?
A. Remove all water hardness
B. Produce drinking-quality water
C. Reduce pollutants to protect public health and the environment
D. Remove all dissolved solids
Correct answer: C
Rationale: Level 1 plants aim to reduce pollutants to safe discharge levels,
not to create potable water.
2. What is the typical range for raw domestic wastewater pH?
,A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–11
Correct answer: C
Rationale: Domestic wastewater typically remains near neutral, slightly
basic.
3. Which wastewater component is measured as BOD₅?
A. Settleable solids
B. Oxygen-demanding organic matter
C. Coliform bacteria
D. Heavy metals
Correct answer: B
Rationale: BOD₅ assesses the biodegradable organic load requiring oxygen.
4. What is the purpose of screening in preliminary treatment?
A. Remove dissolved gases
B. Remove large debris
C. Neutralize pH
D. Remove pathogens
Correct answer: B
,Rationale: Bar screens protect downstream equipment from rags and
debris.
5. Grit chambers are used to remove:
A. Floatable oils
B. Fine silt
C. Sand, gravel, and heavy inorganic particles
D. Dissolved solids
Correct answer: C
Rationale: Grit removal prevents abrasion and damage to pumps.
6. A primary clarifier mainly removes:
A. 100% of BOD
B. Dissolved nutrients
C. Settleable and floatable solids
D. Viruses
Correct answer: C
Rationale: Primary settling targets solids that sink or float.
7. Secondary treatment is primarily a:
, A. Chemical process
B. Mechanical process
C. Biological process
D. Radioactive process
Correct answer: C
Rationale: Biological microbes consume organic matter during secondary
treatment.
8. What organism type is most important in activated sludge?
A. Viruses
B. Protozoa
C. Nematodes
D. Bacteria
Correct answer: D
Rationale: Bacteria drive decomposition of organic matter in aeration
tanks.
9. Aeration tanks supply oxygen to support:
A. Chemical flocculation
B. Microbial growth
C. UV disinfection
D. Sand filtration
Level 1 Practice Exam Questions And
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download
1. What is the primary purpose of wastewater treatment?
A. Remove all water hardness
B. Produce drinking-quality water
C. Reduce pollutants to protect public health and the environment
D. Remove all dissolved solids
Correct answer: C
Rationale: Level 1 plants aim to reduce pollutants to safe discharge levels,
not to create potable water.
2. What is the typical range for raw domestic wastewater pH?
,A. 1–3
B. 4–5
C. 6.5–8.5
D. 9–11
Correct answer: C
Rationale: Domestic wastewater typically remains near neutral, slightly
basic.
3. Which wastewater component is measured as BOD₅?
A. Settleable solids
B. Oxygen-demanding organic matter
C. Coliform bacteria
D. Heavy metals
Correct answer: B
Rationale: BOD₅ assesses the biodegradable organic load requiring oxygen.
4. What is the purpose of screening in preliminary treatment?
A. Remove dissolved gases
B. Remove large debris
C. Neutralize pH
D. Remove pathogens
Correct answer: B
,Rationale: Bar screens protect downstream equipment from rags and
debris.
5. Grit chambers are used to remove:
A. Floatable oils
B. Fine silt
C. Sand, gravel, and heavy inorganic particles
D. Dissolved solids
Correct answer: C
Rationale: Grit removal prevents abrasion and damage to pumps.
6. A primary clarifier mainly removes:
A. 100% of BOD
B. Dissolved nutrients
C. Settleable and floatable solids
D. Viruses
Correct answer: C
Rationale: Primary settling targets solids that sink or float.
7. Secondary treatment is primarily a:
, A. Chemical process
B. Mechanical process
C. Biological process
D. Radioactive process
Correct answer: C
Rationale: Biological microbes consume organic matter during secondary
treatment.
8. What organism type is most important in activated sludge?
A. Viruses
B. Protozoa
C. Nematodes
D. Bacteria
Correct answer: D
Rationale: Bacteria drive decomposition of organic matter in aeration
tanks.
9. Aeration tanks supply oxygen to support:
A. Chemical flocculation
B. Microbial growth
C. UV disinfection
D. Sand filtration
