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Water & Wastewater Operator (WPI/ABC Class I) — Practice Exam

WW equipment: pumps: practice questions

Our Water/Wastewater Operator bank has 11 questions on this topic. Here are 5 of them with answers; the full mock exam draws from every topic, like the real one.

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Question 1 · Wastewater Treatment Class I

What does a sudden drop in a pump's discharge pressure and flow suggest?

  1. Normal wear only, combined with too much electrical power to the motor
  2. A clog, worn impeller or air in the pump
  3. Normal wear only, with too much power
  4. High downstream demand
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B. A clog, worn impeller or air in the pump — Troubleshoot suction and impeller.

Question 2 · Wastewater Treatment Class I

How are lift station pumps usually controlled?

  1. By hand only, or by a timer that starts each pump at set times of day
  2. By level sensors or floats in the wet well
  3. By the outdoor temperature
  4. By the chlorine residual
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B. By level sensors or floats in the wet well — Lead/lag pumps alternate.

Question 3 · Wastewater Treatment Class I

How can an operator tell if a pump impeller is rotating backward?

  1. The motor stops
  2. The motor runs cooler than normal
  3. It runs quieter and flow doubles
  4. Low flow and pressure despite the motor running; check rotation against the arrow
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D. Low flow and pressure despite the motor running; check rotation against the arrow — Reversed wiring after repairs is a common cause.

Question 4 · Wastewater Treatment Class I

What does a mechanical seal on a pump do?

  1. Adds lubrication to the motor
  2. Prevents leakage along the shaft without the drip packing needs
  3. Increases pump speed and lubricates the motor
  4. Increases the pump's speed and supplies lubrication to the motor bearings
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B. Prevents leakage along the shaft without the drip packing needs — Mechanical seals should not leak.

Question 5 · Wastewater Treatment Class I

Which type of pump is commonly used for raw wastewater?

  1. Gear pump
  2. Peristaltic pump
  3. Non-clog centrifugal pump
  4. Diaphragm metering pump with check valves
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C. Non-clog centrifugal pump — They pass solids and rags better.

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