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Classroom activity Grade 10 Careers & CTE

Operator on Shift: A Silverton Incident-Response Role-Play

A grade 10 careers role-play where student teams act as operators at the fictional Silverton utility, judging incident responses against four operator criteria.

Objectives

  1. Students will judge an operator's possible responses to a plant incident against a set of criteria.
  2. Students will name the criteria a chosen response protects and the ones it trades off.
  3. Students will explain why a do-nothing response usually ranks poorly against operator criteria.

Vocabulary

Turbidity
Turbidity is a measure of how cloudy or murky water looks because of tiny particles floating in it. Clear water has low turbidity, and muddy water has high turbidity.
Chlorine residual
Chlorine residual is the small amount of chlorine still left in the water after it leaves the treatment plant. It keeps protecting the water from germs all the way to your faucet.
Effluent
Effluent is the cleaned water that leaves a treatment plant at the end of the process. It is tested carefully before being released to a river, lake, or the ocean.

Also: trade-off

Teacher overview

This is a small-group role-play for teams of three to four students. Each team acts as the operator crew on shift at the fictional Silverton Water Utility. A team draws an incident card that reports one reading drifting out of its safe range, along with three possible responses. The teams do not compute anything; instead they judge the responses against four criteria an operator actually weighs, which turns an abstract idea of "good judgment" into a set of trade-offs students can name and defend.

Activity Directions

  1. Before class, print the four incident cards from the Student Handout, one set per team, and arrange desks into team tables. Tell students that each team is the operator crew on shift at the fictional Silverton Water Utility.
  2. Post the four operator criteria the class will use to judge any response (about 5 minutes): keep the public safe, meet the regulatory limit, keep the system reliable, and control cost. Explain that a real operator rarely satisfies all four at once, so the job is to choose well and to know what is being traded off.
  3. Give each team one incident card. Each card states a reading that is outside its safe range and lists three possible responses labeled A, B, and C.
  4. Teams have 8 minutes to rank the three responses against the four criteria and choose one. They must write down which criteria their choice protects and which it trades off.
  5. Rotate the cards so each team receives a second, different incident, and repeat the 8-minute ranking.
  6. Each team reports its decision on one of its cards to the class, in about one minute, naming the criteria behind the choice.
  7. End the activity once every team has reported. Close with the debrief points in the Answer Key, taking about 10 minutes as a whole class.
Operator on Shift: A Silverton Incident-Response Role-Play — Grade 10 Careers & CTE
Name: ____________________________ Date: ______________

Student Handout

You are the operator crew on shift at the fictional Silverton Water Utility. Read your incident card. Rank responses A, B, and C against the four criteria, then choose one and note what it protects and what it trades off.

Card A - Turbidity. Finished-water turbidity has risen to 0.8 NTU. The plant aims to stay at or below 0.3 NTU. A) Increase the coagulant dose and slow the filters. B) Ignore it, since the water still looks clear. C) Shut the plant at once and buy water from a neighboring town.

Card B - Chlorine residual. The chlorine residual far out in the distribution system has dropped to 0.1 mg/L. Systems usually keep at least 0.2 mg/L there. A) Flush that part of the system and check the plant dose. B) Do nothing until the next monthly sample. C) Triple the plant dose right away.

Card C - Pressure. A pressure zone has fallen to 18 psi. Most states require at least 20 psi to keep contamination out. A) Start a backup pump and search for the cause, such as a main break. B) Wait and see whether the pressure recovers on its own. C) Tell customers to boil water and take no other step.

Card D - Effluent BOD. The wastewater plant's effluent BOD has climbed to 45 mg/L. The plant's permit limit is a 30-day average of 30 mg/L. A) Increase aeration and check the return sludge. B) Release the water anyway to avoid sewer backups. C) Shut off all incoming flow immediately.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Card A: Response A best fits the criteria. Increasing coagulant and slowing the filters protects public safety and meets the 0.3 NTU goal at a modest cost. It trades off some plant capacity while the filters run slower. Response C is safe but very costly and hurts reliability; response B protects nothing.
  2. Card B: Response A best fits. Flushing brings fresh, chlorinated water into the low-residual area and checking the plant dose tests one likely cause, at modest cost. Response C risks overshooting the dose, and response B leaves that area with little protection until the next sample.
  3. Card C: The wait-and-see option is risky because pressure below 20 psi can let contamination enter the mains through backflow. Waiting protects cost and effort but gambles with public safety and the regulatory limit, which is why response A, starting a backup pump and finding the cause, ranks higher.
  4. Debrief: The do-nothing options usually ranked lowest because they protect only cost and effort while failing the safety and regulatory criteria, which operators treat as the highest priorities. A reading outside its safe range does not fix itself, so delay usually raises risk.
  5. Debrief: Criteria often conflict. For example, on Card D releasing the water controls cost and avoids backups but pushes the plant toward violating its 30 mg/L monthly-average limit and threatens the river, so protecting cost trades off safety and compliance.

Differentiation

Support

Give teams a printed criteria checklist with a simple thumbs-up or thumbs-down box for each response, so students can mark each option against each criterion before ranking. Pair stronger and developing readers within each team.

Extension

Ask a team to write a fifth incident card of their own, with a realistic out-of-range reading and three responses, then trade it with another team and compare how the two crews rank the options.

ELL supports

Pre-teach "turbidity," "chlorine residual," "effluent," and "trade-off" with simple definitions and a picture for each. Provide sentence frames for the report step: "We chose response ___. It protects ___. It trades off ___."