North Carolina Wastewater Collection System
Operator — Grade II Certification Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
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QUESTIONS 1–50
1. The primary purpose of a wastewater collection system is to:
A. Store wastewater
B. Convey wastewater to a treatment facility
C. Filter wastewater
D. Disinfect wastewater
Answer: B
The system’s role is conveyance, not treatment.
2. A manhole typically should be installed at changes in:
A. Chemical quality
B. Water temperature
C. Pipe slope or direction
D. Flow velocity
Answer: C
Manholes allow access at key structural transitions.
3. The minimum recommended velocity to prevent solids deposition
in gravity sewers is:
,A. 0.5 ft/s
B. 1.0 ft/s
C. 2.0 ft/s
D. 3.0 ft/s
Answer: C
Velocities of ~2 ft/s help avoid sediment buildup.
4. Hydrogen sulfide is most likely to form in:
A. High-oxygen conditions
B. Low-oxygen conditions
C. High-pressure zones
D. Cold water
Answer: B
Anaerobic conditions promote H₂S generation.
5. The principal cause of sewer line blockages is:
A. UV exposure
B. Excess chlorine
C. Fats, oils, and grease (FOG)
D. Cold weather
Answer: C
FOG solidifies and accumulates easily.
6. A Grade II operator must be able to calculate:
A. Atomic mass
B. Pipe slopes and flow rates
C. Chemical oxidation curves
D. Radiological exposure
, Answer: B
Slope and flow calculations are essential for system operation.
7. Root intrusion into sewers is best prevented by:
A. Lowering pH
B. Increasing pressure
C. Using root-resistant materials
D. Adding chlorine tablets
Answer: C
Modern pipe materials reduce infiltration risks.
8. Force mains operate under:
A. Gravity flow
B. Vacuum
C. Pressure
D. Free flow
Answer: C
Force mains are pressurized by pumps.
9. The primary danger of hydrogen sulfide exposure is:
A. Rash
B. Nausea
C. Respiratory paralysis
D. Hypothermia
Answer: C
H₂S can quickly disable the respiratory system.
10. A sewer line sag is also known as a:
Operator — Grade II Certification Exam
Questions And Correct Answers (Verified
Answers) Plus Rationales 2026 Q&A | Instant
Download Pdf
QUESTIONS 1–50
1. The primary purpose of a wastewater collection system is to:
A. Store wastewater
B. Convey wastewater to a treatment facility
C. Filter wastewater
D. Disinfect wastewater
Answer: B
The system’s role is conveyance, not treatment.
2. A manhole typically should be installed at changes in:
A. Chemical quality
B. Water temperature
C. Pipe slope or direction
D. Flow velocity
Answer: C
Manholes allow access at key structural transitions.
3. The minimum recommended velocity to prevent solids deposition
in gravity sewers is:
,A. 0.5 ft/s
B. 1.0 ft/s
C. 2.0 ft/s
D. 3.0 ft/s
Answer: C
Velocities of ~2 ft/s help avoid sediment buildup.
4. Hydrogen sulfide is most likely to form in:
A. High-oxygen conditions
B. Low-oxygen conditions
C. High-pressure zones
D. Cold water
Answer: B
Anaerobic conditions promote H₂S generation.
5. The principal cause of sewer line blockages is:
A. UV exposure
B. Excess chlorine
C. Fats, oils, and grease (FOG)
D. Cold weather
Answer: C
FOG solidifies and accumulates easily.
6. A Grade II operator must be able to calculate:
A. Atomic mass
B. Pipe slopes and flow rates
C. Chemical oxidation curves
D. Radiological exposure
, Answer: B
Slope and flow calculations are essential for system operation.
7. Root intrusion into sewers is best prevented by:
A. Lowering pH
B. Increasing pressure
C. Using root-resistant materials
D. Adding chlorine tablets
Answer: C
Modern pipe materials reduce infiltration risks.
8. Force mains operate under:
A. Gravity flow
B. Vacuum
C. Pressure
D. Free flow
Answer: C
Force mains are pressurized by pumps.
9. The primary danger of hydrogen sulfide exposure is:
A. Rash
B. Nausea
C. Respiratory paralysis
D. Hypothermia
Answer: C
H₂S can quickly disable the respiratory system.
10. A sewer line sag is also known as a:
