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

WC system: practice questions

Our Water/Wastewater Operator bank has 19 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 is a drop manhole used for?

  1. Storing wastewater during peak flows so the downstream sewer isn't overloaded
  2. Venting sewer gas to the street
  3. Bringing a higher incoming sewer down to a lower one without splashing and erosion
  4. Pumping wastewater
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C. Bringing a higher incoming sewer down to a lower one without splashing and erosion — Drops protect the manhole bench.

Question 2 · Wastewater Collection Class I

Where else must manholes be installed on a sewer?

  1. Only at the treatment plant and at each lift station, since the pipe between can't be reached
  2. Only every mile
  3. At every property line
  4. At changes in grade, size or alignment, at intersections and at the end of each line
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D. At changes in grade, size or alignment, at intersections and at the end of each line — Ten States Standards 34.1.

Question 3 · Wastewater Collection Class I

What is a combined sewer?

  1. A sewer made of two pipe materials joined together
  2. A sewer with two manholes
  3. A sewer carrying both wastewater and stormwater
  4. A sewer with a liner
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C. A sewer carrying both wastewater and stormwater — Combined sewer overflows (CSOs) happen in storms.

Question 4 · Wastewater Collection Class I

What is inflow?

  1. Wastewater leaking out
  2. Stormwater entering a sanitary sewer through direct connections such as roof drains or manhole covers
  3. Sewage backing up into basements
  4. Groundwater seeping through cracks and joints in the pipe, mostly during dry weather when the water table is high
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B. Stormwater entering a sanitary sewer through direct connections such as roof drains or manhole covers — I/I raises flows during storms.

Question 5 · Wastewater Collection Class I

What is exfiltration?

  1. Stormwater entering the sewer through roof drains and cleanouts
  2. Stormwater entering through roof drains and cleanouts
  3. Wastewater leaking out of a sewer into the surrounding soil
  4. Groundwater entering a sewer
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C. Wastewater leaking out of a sewer into the surrounding soil — It can contaminate groundwater.

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