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

WC O&M: practice questions

Our Water/Wastewater Operator bank has 24 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 Collection Class I

What should be done first when an SSO is discovered?

  1. Wait for the next shift, then wash it into a storm drain
  2. Ignore it if small
  3. Wait for the next shift to arrive, then wash the spill into a storm drain
  4. Stop or contain the overflow, protect the public and report it as required
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D. Stop or contain the overflow, protect the public and report it as required — Identify and respond to system failures.

Question 2 · Wastewater Collection Class I

What are roots in sewers commonly treated with?

  1. Chlorine gas fed into the upstream manhole
  2. Concrete
  3. Chlorine gas fed into the manhole
  4. Mechanical cutting or approved chemical root control
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D. Mechanical cutting or approved chemical root control — Roots enter through joints.

Question 3 · Wastewater Collection Class I

What is grouting used for in sewer rehabilitation?

  1. Measuring pipe slope
  2. Sealing leaking joints and laterals to stop infiltration
  3. Cleaning pipes
  4. Painting manholes and measuring flow in sewers
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B. Sealing leaking joints and laterals to stop infiltration — Chemical grouting is common.

Question 4 · Wastewater Collection Class I

How can odors from sewers be controlled?

  1. Adding more grease and opening all manholes
  2. Chemical addition, ventilation control and reducing long detention times
  3. Adding more grease to coat the pipe and opening all manholes to vent odors
  4. Raising wastewater temperature
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B. Chemical addition, ventilation control and reducing long detention times — Hydrogen sulfide causes odor and corrosion.

Question 5 · Wastewater Collection Class I

What is hydro-excavation?

  1. Lining pipes
  2. Pushing pipe under a road with a jack
  3. Digging with a backhoe only, without locating utilities first
  4. Using pressurized water and a vacuum to dig safely around utilities
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D. Using pressurized water and a vacuum to dig safely around utilities — Reduces risk of hitting buried lines.

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