Missouri Wastewater Collection System Operator
Certification (Missouri DNR) Practice Examination
Newest 2025 – 2026 Updated Questions From
Actual Exams Complete 100 Questions And Correct
Detailed Answers (Verified Answers) |Already
Graded A+||Brand New!!
1. What is the primary purpose of a wastewater collection system?
A. To treat wastewater
B. To transport wastewater to a treatment facility
C. To disinfect wastewater
D. To store wastewater indefinitely
✔ Correct Answer: B. To transport wastewater to a treatment facility
Explanation: Wastewater collection systems are designed to convey sewage
from its source to treatment plants, not to treat or store it.
2. Which type of sewer carries both stormwater and sanitary wastewater?
A. Sanitary sewer
B. Storm sewer
C. Combined sewer
D. Force main
✔ Correct Answer: C. Combined sewer
Explanation: Combined sewers transport both stormwater and sanitary
flows in a single pipe system.
3. What is infiltration in a sewer system?
A. Illegal connections
B. Rainwater entering through manhole covers
C. Groundwater entering through defects
D. Industrial discharge
, ✔ Correct Answer: C. Groundwater entering through defects
Explanation: Infiltration refers to groundwater entering pipes through
cracks, joints, or defects.
4. What is inflow?
A. Groundwater entering pipes
B. Surface water entering directly
C. Wastewater treatment process
D. Sludge buildup
✔ Correct Answer: B. Surface water entering directly
Explanation: Inflow is stormwater entering through direct connections like
roof drains or manholes.
5. Which gas is most commonly associated with sewer corrosion?
A. Oxygen
B. Methane
C. Hydrogen sulfide
D. Nitrogen
✔ Correct Answer: C. Hydrogen sulfide
Explanation: Hydrogen sulfide forms sulfuric acid, which corrodes sewer
infrastructure.
6. What is the normal slope requirement for gravity sewers designed to
prevent solids deposition?
A. Flat slope
B. Zero slope
C. Minimum velocity slope
D. Negative slope
✔ Correct Answer: C. Minimum velocity slope
Explanation: Sewers must maintain a slope that ensures self-cleansing
velocity to prevent sediment buildup.
7. What is a force main?
A. A gravity sewer
, B. A pressurized pipeline
C. A storm drain
D. A treatment tank
✔ Correct Answer: B. A pressurized pipeline
Explanation: Force mains carry wastewater under pressure from pumps.
8. Which equipment is used to remove blockages in sewer lines?
A. Chlorinator
B. Jetting machine
C. Clarifier
D. Aerator
✔ Correct Answer: B. Jetting machine
Explanation: Jetting machines use high-pressure water to clear
obstructions.
9. What is the main function of a manhole?
A. Treat wastewater
B. Store wastewater
C. Provide access to the sewer system
D. Pump wastewater
✔ Correct Answer: C. Provide access to the sewer system
Explanation: Manholes allow inspection, maintenance, and cleaning of
sewer lines.
10.What is a lift station used for?
A. Reducing flow
B. Increasing pressure to move wastewater
C. Treating wastewater
D. Storing sludge
✔ Correct Answer: B. Increasing pressure to move wastewater
Explanation: Lift stations pump wastewater to higher elevations.
11.What condition causes septic wastewater?
A. High oxygen levels
Certification (Missouri DNR) Practice Examination
Newest 2025 – 2026 Updated Questions From
Actual Exams Complete 100 Questions And Correct
Detailed Answers (Verified Answers) |Already
Graded A+||Brand New!!
1. What is the primary purpose of a wastewater collection system?
A. To treat wastewater
B. To transport wastewater to a treatment facility
C. To disinfect wastewater
D. To store wastewater indefinitely
✔ Correct Answer: B. To transport wastewater to a treatment facility
Explanation: Wastewater collection systems are designed to convey sewage
from its source to treatment plants, not to treat or store it.
2. Which type of sewer carries both stormwater and sanitary wastewater?
A. Sanitary sewer
B. Storm sewer
C. Combined sewer
D. Force main
✔ Correct Answer: C. Combined sewer
Explanation: Combined sewers transport both stormwater and sanitary
flows in a single pipe system.
3. What is infiltration in a sewer system?
A. Illegal connections
B. Rainwater entering through manhole covers
C. Groundwater entering through defects
D. Industrial discharge
, ✔ Correct Answer: C. Groundwater entering through defects
Explanation: Infiltration refers to groundwater entering pipes through
cracks, joints, or defects.
4. What is inflow?
A. Groundwater entering pipes
B. Surface water entering directly
C. Wastewater treatment process
D. Sludge buildup
✔ Correct Answer: B. Surface water entering directly
Explanation: Inflow is stormwater entering through direct connections like
roof drains or manholes.
5. Which gas is most commonly associated with sewer corrosion?
A. Oxygen
B. Methane
C. Hydrogen sulfide
D. Nitrogen
✔ Correct Answer: C. Hydrogen sulfide
Explanation: Hydrogen sulfide forms sulfuric acid, which corrodes sewer
infrastructure.
6. What is the normal slope requirement for gravity sewers designed to
prevent solids deposition?
A. Flat slope
B. Zero slope
C. Minimum velocity slope
D. Negative slope
✔ Correct Answer: C. Minimum velocity slope
Explanation: Sewers must maintain a slope that ensures self-cleansing
velocity to prevent sediment buildup.
7. What is a force main?
A. A gravity sewer
, B. A pressurized pipeline
C. A storm drain
D. A treatment tank
✔ Correct Answer: B. A pressurized pipeline
Explanation: Force mains carry wastewater under pressure from pumps.
8. Which equipment is used to remove blockages in sewer lines?
A. Chlorinator
B. Jetting machine
C. Clarifier
D. Aerator
✔ Correct Answer: B. Jetting machine
Explanation: Jetting machines use high-pressure water to clear
obstructions.
9. What is the main function of a manhole?
A. Treat wastewater
B. Store wastewater
C. Provide access to the sewer system
D. Pump wastewater
✔ Correct Answer: C. Provide access to the sewer system
Explanation: Manholes allow inspection, maintenance, and cleaning of
sewer lines.
10.What is a lift station used for?
A. Reducing flow
B. Increasing pressure to move wastewater
C. Treating wastewater
D. Storing sludge
✔ Correct Answer: B. Increasing pressure to move wastewater
Explanation: Lift stations pump wastewater to higher elevations.
11.What condition causes septic wastewater?
A. High oxygen levels
