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

WT equipment: practice questions

Our Water/Wastewater Operator bank has 20 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 · Water Treatment Class I

Why is preventive maintenance done on plant equipment?

  1. To reduce breakdowns and extend equipment life
  2. To use more lubricants and spare parts each year
  3. Only after equipment fails, so parts aren't replaced before they wear out
  4. To meet the state's billing rules
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A. To reduce breakdowns and extend equipment life — PM is scheduled based on manufacturer guidance.

Question 2 · Water Treatment Class I

What does a motor running hot with a burning smell suggest?

  1. Normal operation for a new motor; it needs a higher voltage supply to run cooler
  2. It needs to run faster
  3. Overload, poor ventilation or bearing problems; shut it down and investigate
  4. Normal operation; it needs more voltage to run faster
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C. Overload, poor ventilation or bearing problems; shut it down and investigate — Check amps, cooling and bearings.

Question 3 · Water Treatment Class I

How is a small chlorine gas leak located?

  1. With a lit match held near each fitting until the flame changes color
  2. With water spray
  3. With a soap solution only
  4. With ammonia vapor, which forms a white cloud at the leak
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D. With ammonia vapor, which forms a white cloud at the leak — Never put water on a chlorine leak.

Question 4 · Water Treatment Class I

Why should water never be sprayed on a leaking chlorine cylinder?

  1. Water forms acid that makes the leak worse
  2. It is the recommended first step
  3. It dilutes the chlorine so the gas becomes harmless
  4. It cools the cylinder too much and freezes the valve shut
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A. Water forms acid that makes the leak worse — Corrosion enlarges the leak.

Question 5 · Water Treatment Class I

What does a magnetic flowmeter measure?

  1. Turbidity
  2. Chlorine residual
  3. Flow rate, from the voltage induced by water moving through a magnetic field
  4. Pressure in the pipe, using a spring-loaded diaphragm and a dial gauge
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C. Flow rate, from the voltage induced by water moving through a magnetic field — It has no moving parts in the flow.

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