Wastewater Collection System QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWES) Q&A 2026
VERSION |INSTANT DOWNLOADED PDF
Q1. What is the primary purpose of a wastewater collection system?
A. To supply drinking water
B. To transport sewage from homes to treatment facilities
C. To irrigate agricultural land
D. To filter stormwater only
Answer: B. The main purpose is to transport sewage safely from residential,
commercial, and industrial sources to a treatment plant.
Q2. Which type of sewer system carries both stormwater and sewage in the
same pipe?
A. Separate sewer system
B. Combined sewer system
C. Sanitary sewer system
D. Trunk sewer system
Answer: B. Combined sewer systems transport both stormwater and sewage,
often leading to overflow events during heavy rainfall.
Q3. What is the function of a manhole in a sewer system?
A. To add chemicals to wastewater
B. To allow access for inspection, cleaning, and maintenance
C. To treat wastewater biologically
D. To measure flow rate automatically
Answer: B. Manholes provide access points for maintenance, inspection, and
cleaning of sewer lines.
Q4. What is the typical minimum slope for a sanitary sewer line to maintain self-
cleansing velocity?
A. 0.1%
B. 0.5%
C. 1%
,D. 5%
Answer: C. A slope of around 1% ensures sewage moves at sufficient velocity to
prevent solids deposition.
Q5. What type of pipe is commonly used for sewer collection systems?
A. PVC
B. Cast iron
C. Concrete
D. All of the above
Answer: D. Depending on location and cost, PVC, cast iron, and concrete pipes are
all commonly used in wastewater collection.
Q6. Which of the following can cause sewer blockages?
A. Grease and fats
B. Tree roots
C. Debris and solids
D. All of the above
Answer: D. Blockages often result from a combination of grease, roots, and solids
entering the sewer system.
Q7. What is the purpose of a lift station in a wastewater system?
A. To treat wastewater
B. To pump sewage from lower to higher elevation
C. To remove solids from wastewater
D. To measure water quality
Answer: B. Lift stations pump wastewater uphill where gravity flow is insufficient.
Q8. What is the typical flow velocity required to prevent sedimentation in
sewers?
A. 0.5 ft/s
B. 2 ft/s
C. 10 ft/s
D. 20 ft/s
Answer: B. A minimum flow velocity of about 2 ft/s is recommended to avoid
solids settling.
Q9. Which of the following is considered a sanitary sewer system?
A. A sewer carrying only sewage
, B. A sewer carrying only stormwater
C. A sewer carrying both sewage and stormwater
D. A sewer used for irrigation
Answer: A. Sanitary sewers are designed to carry only wastewater from homes
and businesses.
Q10. What is infiltration in a sewer system?
A. Water entering the sewer from groundwater
B. Wastewater leaking into the ground
C. Sewage spilling during storms
D. Flow from a lift station
Answer: A. Infiltration refers to groundwater entering the sewer through cracks or
joints.
Q11. What is exfiltration in sewer systems?
A. Wastewater leaving the sewer and entering the ground
B. Stormwater entering the sewer
C. Wastewater treatment
D. Pumping sewage uphill
Answer: A. Exfiltration is the leakage of sewage from the sewer into surrounding
soil.
Q12. What is the main advantage of a separate sewer system?
A. Easier to construct
B. Reduces the risk of overflows during storms
C. Lower cost of maintenance
D. Requires fewer pipes
Answer: B. By separating stormwater from sanitary sewage, overflows during
rainfall are minimized.
Q13. What is the function of a sewer vent system?
A. To allow odors to escape and maintain atmospheric pressure
B. To prevent solids from entering
C. To treat wastewater
D. To increase flow velocity
Answer: A. Venting allows gases to escape and prevents vacuum conditions that
could disrupt flow.
CORRECT ANSWERS (VERIFIED ANSWES) Q&A 2026
VERSION |INSTANT DOWNLOADED PDF
Q1. What is the primary purpose of a wastewater collection system?
A. To supply drinking water
B. To transport sewage from homes to treatment facilities
C. To irrigate agricultural land
D. To filter stormwater only
Answer: B. The main purpose is to transport sewage safely from residential,
commercial, and industrial sources to a treatment plant.
Q2. Which type of sewer system carries both stormwater and sewage in the
same pipe?
A. Separate sewer system
B. Combined sewer system
C. Sanitary sewer system
D. Trunk sewer system
Answer: B. Combined sewer systems transport both stormwater and sewage,
often leading to overflow events during heavy rainfall.
Q3. What is the function of a manhole in a sewer system?
A. To add chemicals to wastewater
B. To allow access for inspection, cleaning, and maintenance
C. To treat wastewater biologically
D. To measure flow rate automatically
Answer: B. Manholes provide access points for maintenance, inspection, and
cleaning of sewer lines.
Q4. What is the typical minimum slope for a sanitary sewer line to maintain self-
cleansing velocity?
A. 0.1%
B. 0.5%
C. 1%
,D. 5%
Answer: C. A slope of around 1% ensures sewage moves at sufficient velocity to
prevent solids deposition.
Q5. What type of pipe is commonly used for sewer collection systems?
A. PVC
B. Cast iron
C. Concrete
D. All of the above
Answer: D. Depending on location and cost, PVC, cast iron, and concrete pipes are
all commonly used in wastewater collection.
Q6. Which of the following can cause sewer blockages?
A. Grease and fats
B. Tree roots
C. Debris and solids
D. All of the above
Answer: D. Blockages often result from a combination of grease, roots, and solids
entering the sewer system.
Q7. What is the purpose of a lift station in a wastewater system?
A. To treat wastewater
B. To pump sewage from lower to higher elevation
C. To remove solids from wastewater
D. To measure water quality
Answer: B. Lift stations pump wastewater uphill where gravity flow is insufficient.
Q8. What is the typical flow velocity required to prevent sedimentation in
sewers?
A. 0.5 ft/s
B. 2 ft/s
C. 10 ft/s
D. 20 ft/s
Answer: B. A minimum flow velocity of about 2 ft/s is recommended to avoid
solids settling.
Q9. Which of the following is considered a sanitary sewer system?
A. A sewer carrying only sewage
, B. A sewer carrying only stormwater
C. A sewer carrying both sewage and stormwater
D. A sewer used for irrigation
Answer: A. Sanitary sewers are designed to carry only wastewater from homes
and businesses.
Q10. What is infiltration in a sewer system?
A. Water entering the sewer from groundwater
B. Wastewater leaking into the ground
C. Sewage spilling during storms
D. Flow from a lift station
Answer: A. Infiltration refers to groundwater entering the sewer through cracks or
joints.
Q11. What is exfiltration in sewer systems?
A. Wastewater leaving the sewer and entering the ground
B. Stormwater entering the sewer
C. Wastewater treatment
D. Pumping sewage uphill
Answer: A. Exfiltration is the leakage of sewage from the sewer into surrounding
soil.
Q12. What is the main advantage of a separate sewer system?
A. Easier to construct
B. Reduces the risk of overflows during storms
C. Lower cost of maintenance
D. Requires fewer pipes
Answer: B. By separating stormwater from sanitary sewage, overflows during
rainfall are minimized.
Q13. What is the function of a sewer vent system?
A. To allow odors to escape and maintain atmospheric pressure
B. To prevent solids from entering
C. To treat wastewater
D. To increase flow velocity
Answer: A. Venting allows gases to escape and prevents vacuum conditions that
could disrupt flow.
