SC Wastewater Treatment Operator
Collection System Maintenance Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which maintenance activity is most effective for preventing excessive
grease accumulation in sanitary sewer lines?
A. Increasing lift station pumping rates
B. Periodically applying chlorine to the sewer
C. Implementing routine sewer cleaning schedules
D. Reducing manhole inspections
C. Implementing routine sewer cleaning schedules
Routine sewer cleaning removes grease, debris, and sediment before
significant blockages develop. Preventive cleaning is one of the most
effective collection system maintenance practices.
2. What is the primary purpose of a sanitary sewer manhole?
A. To increase wastewater velocity
B. To provide system access for inspection and maintenance
C. To disinfect wastewater
D. To store excess flow
B. To provide system access for inspection and maintenance
,Manholes allow operators to inspect, clean, test, and repair sewer lines.
They also provide access points for equipment and personnel.
3. Which condition most commonly causes sanitary sewer overflows
(SSOs)?
A. Low wastewater temperature
B. Excessive dissolved oxygen
C. Blockages and hydraulic surcharging
D. High alkalinity
C. Blockages and hydraulic surcharging
SSOs frequently occur when sewer capacity is exceeded or when blockages
restrict flow, causing wastewater to back up and overflow.
4. During sewer cleaning, a combination sewer jetter primarily uses:
A. Electrical current
B. High-pressure water
C. Chlorine gas
D. Compressed oxygen
B. High-pressure water
Jetting equipment uses high-pressure water to scour pipe walls and move
debris toward collection points for removal.
5. What is the greatest safety hazard associated with entering a sewer
manhole?
A. Noise exposure
B. Ultraviolet radiation
C. Confined space hazards
D. High humidity
C. Confined space hazards
,Manholes are confined spaces that may contain toxic gases, oxygen
deficiency, or explosive atmospheres, requiring strict safety procedures.
6. Which gas is commonly monitored because it is toxic and frequently
found in sewer systems?
A. Nitrogen
B. Hydrogen sulfide
C. Helium
D. Argon
B. Hydrogen sulfide
Hydrogen sulfide can cause serious health effects and may be present in
dangerous concentrations within collection systems.
7. Root intrusion into sewer mains is most likely to occur through:
A. Pump impellers
B. Service meters
C. Pipe joints and cracks
D. Force main valves
C. Pipe joints and cracks
Tree roots seek moisture and commonly enter sewer pipes through
defective joints, cracks, and other openings.
8. Which equipment is commonly used to inspect the interior condition
of sewer pipes?
A. Spectrophotometer
B. CCTV camera system
C. Turbidimeter
D. Jar testing apparatus
B. CCTV camera system
, Closed-circuit television inspection allows operators to evaluate pipe
conditions without excavation.
9. A force main differs from a gravity sewer because wastewater is moved
by:
A. Atmospheric pressure only
B. Gravity alone
C. Mechanical pumping under pressure
D. Evaporation
C. Mechanical pumping under pressure
Force mains transport wastewater using pumps that create pressure
sufficient to move flow through the system.
10. Which maintenance practice helps reduce infiltration into sewer
systems?
A. Increasing detention time
B. Sealing cracks and defective joints
C. Raising wastewater temperature
D. Lowering lift station capacity
B. Sealing cracks and defective joints
Repairing structural defects prevents groundwater from entering sewer
lines and increasing treatment plant flows.
11. What does inflow refer to in a collection system?
A. Wastewater entering from homes
B. Groundwater entering through cracks
C. Stormwater entering through direct connections
D. Industrial discharge only
C. Stormwater entering through direct connections
Collection System Maintenance Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationale 2026
Q&A| Instant Download Pdf
1. Which maintenance activity is most effective for preventing excessive
grease accumulation in sanitary sewer lines?
A. Increasing lift station pumping rates
B. Periodically applying chlorine to the sewer
C. Implementing routine sewer cleaning schedules
D. Reducing manhole inspections
C. Implementing routine sewer cleaning schedules
Routine sewer cleaning removes grease, debris, and sediment before
significant blockages develop. Preventive cleaning is one of the most
effective collection system maintenance practices.
2. What is the primary purpose of a sanitary sewer manhole?
A. To increase wastewater velocity
B. To provide system access for inspection and maintenance
C. To disinfect wastewater
D. To store excess flow
B. To provide system access for inspection and maintenance
,Manholes allow operators to inspect, clean, test, and repair sewer lines.
They also provide access points for equipment and personnel.
3. Which condition most commonly causes sanitary sewer overflows
(SSOs)?
A. Low wastewater temperature
B. Excessive dissolved oxygen
C. Blockages and hydraulic surcharging
D. High alkalinity
C. Blockages and hydraulic surcharging
SSOs frequently occur when sewer capacity is exceeded or when blockages
restrict flow, causing wastewater to back up and overflow.
4. During sewer cleaning, a combination sewer jetter primarily uses:
A. Electrical current
B. High-pressure water
C. Chlorine gas
D. Compressed oxygen
B. High-pressure water
Jetting equipment uses high-pressure water to scour pipe walls and move
debris toward collection points for removal.
5. What is the greatest safety hazard associated with entering a sewer
manhole?
A. Noise exposure
B. Ultraviolet radiation
C. Confined space hazards
D. High humidity
C. Confined space hazards
,Manholes are confined spaces that may contain toxic gases, oxygen
deficiency, or explosive atmospheres, requiring strict safety procedures.
6. Which gas is commonly monitored because it is toxic and frequently
found in sewer systems?
A. Nitrogen
B. Hydrogen sulfide
C. Helium
D. Argon
B. Hydrogen sulfide
Hydrogen sulfide can cause serious health effects and may be present in
dangerous concentrations within collection systems.
7. Root intrusion into sewer mains is most likely to occur through:
A. Pump impellers
B. Service meters
C. Pipe joints and cracks
D. Force main valves
C. Pipe joints and cracks
Tree roots seek moisture and commonly enter sewer pipes through
defective joints, cracks, and other openings.
8. Which equipment is commonly used to inspect the interior condition
of sewer pipes?
A. Spectrophotometer
B. CCTV camera system
C. Turbidimeter
D. Jar testing apparatus
B. CCTV camera system
, Closed-circuit television inspection allows operators to evaluate pipe
conditions without excavation.
9. A force main differs from a gravity sewer because wastewater is moved
by:
A. Atmospheric pressure only
B. Gravity alone
C. Mechanical pumping under pressure
D. Evaporation
C. Mechanical pumping under pressure
Force mains transport wastewater using pumps that create pressure
sufficient to move flow through the system.
10. Which maintenance practice helps reduce infiltration into sewer
systems?
A. Increasing detention time
B. Sealing cracks and defective joints
C. Raising wastewater temperature
D. Lowering lift station capacity
B. Sealing cracks and defective joints
Repairing structural defects prevents groundwater from entering sewer
lines and increasing treatment plant flows.
11. What does inflow refer to in a collection system?
A. Wastewater entering from homes
B. Groundwater entering through cracks
C. Stormwater entering through direct connections
D. Industrial discharge only
C. Stormwater entering through direct connections
