TEXAS WASTEWATER CLASS A NEWEST ACTUAL EXAM COMPLETE 300 QESTIONS
AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
Question 1
A wastewater pipe has a slope of 4 feet in 200 feet, it is referred to as:
• Correct Answer: c. 0.02 feet per foot; d. two percent
• Rationale: Slope is calculated as "rise over run" (the change in elevation divided by the
horizontal distance).
4 ft (rise)
Slope = = 0.02 ft/ft
200 ft (run)
To convert this decimal to a percentage, multiply by 100:
0.02 × 100 = 2%
Question 2
When laying bell and spigot wastewater pipe:
• Correct Answer: trench bedding should be scooped out at joints (to support pipe on the
barrel); the bell end should be pointed upstream.
• Rationale: Properly scooping out bedding at the joints prevents "point loading," where
the weight of the pipe and backfill rests solely on the bell, which can cause the pipe to
shear or crack. The barrel (body) of the pipe should be fully supported. Installing the bell
end facing upstream (against the flow) creates a smoother hydraulic transition for the
wastewater flowing into the next pipe segment and minimizes the risk of exfiltration or
infiltration if the joint seal is compromised.
Question 3
Motivating workers to do a better job is best done by:
• Correct Answer: letting workers participate in setting goals.
, 2
• Rationale: Management psychology suggests that when employees are involved in the
planning process and goal setting, they develop a sense of ownership ("buy-in"). This
intrinsic motivation is generally more effective and sustainable than simple external
rewards or punishment.
Question 4
One important element of a good communicator is:
• Correct Answer: Good listener.
• Rationale: Communication is a two-way process involving sending and receiving
messages. A supervisor or operator cannot effectively communicate instructions, safety
protocols, or feedback without first actively listening to understand the context, concerns,
or technical details provided by others.
Question 5
A 24-inch wastewater interceptor is observed to be flowing half-full at 3 fps. The
approximate volume of wastewater flowing through the line is:
• Correct Answer: 2,115 gpm
• Rationale:
1. Calculate the Area (
𝐴
): A 24-inch pipe has a diameter of 2 feet and a radius (
𝑟
) of 1 foot.
𝐴(full) = 𝜋 × 𝑟 2 = 3.14 × 1 ft × 1 ft = 3.14 sq ft
, 3
2. Adjust for Half-Full:
3.14
𝐴(half) = = 1.57 sq ft
2
3. Calculate Flow Rate (
𝑄
) in cfs: Formula is
𝑄 =𝐴×𝑉
(Velocity)
𝑄 = 1.57 sq ft × 3 fps = 4.71 cubic feet per second (cfs)
4. Convert to Gallons Per Minute (gpm): (
1 cfs = 448.8 gpm
)
4.71 cfs × 448.8 = 2,113.8 gpm
(Rounds to 2,115 gpm).
Question 6
When using a fire hydrant to flush wastewater lines:
• Correct Answer: d. all of the above (open/close slowly, use external valve, use air
gap/backflow device).
• Rationale:
, 4
o Slow operation: Prevents "water hammer," a hydraulic shock wave that can burst
pipes or damage the hydrant.
o External valve: Protects the internal hydrant valve from wear and allows for flow
throttling (hydrants are designed to be fully open or fully closed).
o Air gap/Backflow: Essential to prevent wastewater contamination from being
siphoned back into the potable water supply (cross-connection control).
Question 7
A collection system that averages 1.0 mgd or more must employ:
• Correct Answer: a. at least one Class III Collection operator or a Class B Wastewater
operator.
• Rationale: According to TCEQ regulations (30 TAC Chapter 30), higher flows indicate a
more complex system with greater environmental risk. Therefore, the designated operator
in responsible charge must hold a higher level of licensure commensurate with the system
size (1.0 MGD threshold).
Question 8
Before making major changes in the collection system or the treatment plant, detailed
designs by a professional engineer must be submitted to TCEQ before:
• Correct Answer: beginning construction.
• Rationale: Regulatory compliance requires a review of the Summary Transmittal Letter
and engineering plans to ensure the proposed changes meet state design criteria (Chapter
217) and will protect public health. This review must happen before any physical work
begins to prevent costly corrections or environmental violations.
Question 9
When connecting a public water supply to any source of potential contamination, an air
gap of what size must be provided?
• Correct Answer: two times the inlet pipe diameter.
AND CORRECT DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY GRADED A+
Question 1
A wastewater pipe has a slope of 4 feet in 200 feet, it is referred to as:
• Correct Answer: c. 0.02 feet per foot; d. two percent
• Rationale: Slope is calculated as "rise over run" (the change in elevation divided by the
horizontal distance).
4 ft (rise)
Slope = = 0.02 ft/ft
200 ft (run)
To convert this decimal to a percentage, multiply by 100:
0.02 × 100 = 2%
Question 2
When laying bell and spigot wastewater pipe:
• Correct Answer: trench bedding should be scooped out at joints (to support pipe on the
barrel); the bell end should be pointed upstream.
• Rationale: Properly scooping out bedding at the joints prevents "point loading," where
the weight of the pipe and backfill rests solely on the bell, which can cause the pipe to
shear or crack. The barrel (body) of the pipe should be fully supported. Installing the bell
end facing upstream (against the flow) creates a smoother hydraulic transition for the
wastewater flowing into the next pipe segment and minimizes the risk of exfiltration or
infiltration if the joint seal is compromised.
Question 3
Motivating workers to do a better job is best done by:
• Correct Answer: letting workers participate in setting goals.
, 2
• Rationale: Management psychology suggests that when employees are involved in the
planning process and goal setting, they develop a sense of ownership ("buy-in"). This
intrinsic motivation is generally more effective and sustainable than simple external
rewards or punishment.
Question 4
One important element of a good communicator is:
• Correct Answer: Good listener.
• Rationale: Communication is a two-way process involving sending and receiving
messages. A supervisor or operator cannot effectively communicate instructions, safety
protocols, or feedback without first actively listening to understand the context, concerns,
or technical details provided by others.
Question 5
A 24-inch wastewater interceptor is observed to be flowing half-full at 3 fps. The
approximate volume of wastewater flowing through the line is:
• Correct Answer: 2,115 gpm
• Rationale:
1. Calculate the Area (
𝐴
): A 24-inch pipe has a diameter of 2 feet and a radius (
𝑟
) of 1 foot.
𝐴(full) = 𝜋 × 𝑟 2 = 3.14 × 1 ft × 1 ft = 3.14 sq ft
, 3
2. Adjust for Half-Full:
3.14
𝐴(half) = = 1.57 sq ft
2
3. Calculate Flow Rate (
𝑄
) in cfs: Formula is
𝑄 =𝐴×𝑉
(Velocity)
𝑄 = 1.57 sq ft × 3 fps = 4.71 cubic feet per second (cfs)
4. Convert to Gallons Per Minute (gpm): (
1 cfs = 448.8 gpm
)
4.71 cfs × 448.8 = 2,113.8 gpm
(Rounds to 2,115 gpm).
Question 6
When using a fire hydrant to flush wastewater lines:
• Correct Answer: d. all of the above (open/close slowly, use external valve, use air
gap/backflow device).
• Rationale:
, 4
o Slow operation: Prevents "water hammer," a hydraulic shock wave that can burst
pipes or damage the hydrant.
o External valve: Protects the internal hydrant valve from wear and allows for flow
throttling (hydrants are designed to be fully open or fully closed).
o Air gap/Backflow: Essential to prevent wastewater contamination from being
siphoned back into the potable water supply (cross-connection control).
Question 7
A collection system that averages 1.0 mgd or more must employ:
• Correct Answer: a. at least one Class III Collection operator or a Class B Wastewater
operator.
• Rationale: According to TCEQ regulations (30 TAC Chapter 30), higher flows indicate a
more complex system with greater environmental risk. Therefore, the designated operator
in responsible charge must hold a higher level of licensure commensurate with the system
size (1.0 MGD threshold).
Question 8
Before making major changes in the collection system or the treatment plant, detailed
designs by a professional engineer must be submitted to TCEQ before:
• Correct Answer: beginning construction.
• Rationale: Regulatory compliance requires a review of the Summary Transmittal Letter
and engineering plans to ensure the proposed changes meet state design criteria (Chapter
217) and will protect public health. This review must happen before any physical work
begins to prevent costly corrections or environmental violations.
Question 9
When connecting a public water supply to any source of potential contamination, an air
gap of what size must be provided?
• Correct Answer: two times the inlet pipe diameter.
