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Graphic organizer Grade 9 Careers & CTE

When Filter Turbidity Climbs at Millgate: A Response Chain

A grade 9 cause-and-effect organizer that walks a fictional plant's turbidity response step by step, naming who acts at each stage and what each record must show.

Objectives

  1. Students will place the steps of a turbidity response in the order the written procedure sets.
  2. Students will name the role that acts at each step of the response.
  3. Students will state the exception the procedure defines for an instrument reading high.

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.
Backwash
Backwash is when a treatment plant reverses the flow of water through a filter to flush out the dirt and particles it has trapped. It is like rinsing out a dirty sponge so the filter can keep working well.
Jar test
A jar test is a small-scale experiment operators run in the lab before treating a whole tank of water, testing different amounts of chemical in separate jars to see which dose clears the water best. It helps operators avoid wasting chemicals or under-treating the water.

Also: alert setpoint, calibration, excursion

Teacher overview

This organizer is a five-link cause-and-effect chain with one exception branch, built from the filter procedure of the fictional Millgate Water Treatment Plant. Each link carries three cells: what happens, which role acts, and what the record must show afterward, so students see that a plant response is a sequence of documented handoffs rather than a single decision by one person. The chain suits a careers unit because the same event passes through an operator, a laboratory technician, an instrument technician, a compliance coordinator, and a supervisor within a few hours. The common misconception this organizer corrects is that a rising turbidity reading always means the water changed; a meter that has drifted out of calibration produces the same rising line, which is why the procedure sends someone to check the instrument as well as the water.

When Filter Turbidity Climbs at Millgate: A Response Chain — Grade 9 Careers & CTE
Name: ____________________________ Date: ______________

Organizer

The filter procedure at the fictional Millgate Water Treatment Plant, in brief:

  • Millgate sets its own alert at 0.15 NTU on any single filter.
  • The shift operator logs the time, the filter, and the reading.
  • The operator then checks the coagulant dose.
  • The laboratory runs a jar test to confirm that dose.
  • The filter comes out of service for a backwash.
  • The instrument technician checks the meter against a standard.
  • Finished water must stay at or below 0.3 NTU in 95 percent of monthly samples.
  • It must never pass 1 NTU.
  • The filter returns to service after two readings below the alert.
  • The shift supervisor signs the entry.
  • One exception applies. If the calibration check shows the meter read high, the crew still logs the excursion.
  • The record must then state that the meter, not the water, caused the reading.

Fill in the three empty cells in each link, then complete the exception row.

Step What happens Who acts What the record must show
1. The alert
2. Check the dose →
3. Take the filter offline →
4. Check the finished water →
5. Return to service →
Exception

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

Completed Exemplar
Step What happens Who acts What the record must show
1. The alert The online meter on one filter rises past the fictional Millgate alert of 0.15 NTU Shift operator, watching the control screen The time, the filter number, and the reading that crossed the alert
2. Check the dose → The operator reviews the coagulant dose while the laboratory runs a jar test on the raw water Shift operator with the laboratory technician The doses tested in the jar test and the dose the plant chose
3. Take the filter offline → The filter is removed from service and backwashed, and the meter is checked against a calibration standard Shift operator with the instrument technician A work order number and the calibration result for that meter
4. Check the finished water → Finished water is compared with the limits of 0.3 NTU in 95 percent of monthly samples and 1 NTU at any time Compliance coordinator The sample results, and any report filed with the state drinking water program
5. Return to service → The filter goes back online after two consecutive readings below the alert Shift supervisor The return time and the supervisor's signature on the log entry
Exception The calibration check shows the meter itself was reading high, so the water may never have left the normal range Instrument technician, with the shift supervisor confirming The excursion is still logged, with a note that the meter, not the water, caused the reading

Differentiation

Support

Pre-fill the "Who acts" column for all five links and ask these students to complete only the other two columns. Provide the fictional Millgate procedure as numbered cards students can place in order on a desk before writing.

Extension

Ask these students to add a sixth link for the case in which the finished water passes 1 NTU during the response, naming who acts and what additional record the fictional Millgate plant would need.

ELL supports

Pre-teach turbidity, alert setpoint, backwash, and calibration with a simple sketch of a filter, a meter, and a control screen. Allow cells to be completed with short phrases, and pair students so one reads the procedure aloud while the other writes.

Extensions

Ask students to compare this chain with the response their school would follow if a fire alarm sounded, listing which roles exist in both sequences. The comparison makes the point that documented handoffs are how any organization keeps a fast decision reviewable afterward.