Project Grade 11 Careers & CTE
Okemont Booster Station: A Pump Replacement Recommendation
A grade 11 careers project in which teams screen three pump options against stated constraints and recommend one to a fictional maintenance superintendent.
Objectives
- Students will write stated project constraints as inequalities and screen three options against them.
- Students will compare surviving options on seasonal energy cost, redundancy, and maintenance load.
- Students will recommend one option in a memo and defend it in a briefing to a panel.
Vocabulary
Key words: duty point, total head, best efficiency point, parallel operation, scope of practice, installed cost
Teacher overview
Teams act as the maintenance planning group at a fictional water district and recommend which of three pumps should replace a failing unit at a booster station. The driving question is which option meets every stated constraint and then earns the money it costs. The final deliverables are a constraint screening table, a recommendation memo to the maintenance superintendent, a maintenance and training plan, and a six-minute briefing. One misconception should be named in the first session, because students often reach for the largest pump on the sheet. A pump that is oversized for its duty point operates away from its best efficiency point, wastes energy every hour it runs, and in a booster station can start and stop often enough to shorten the life of the motor. Oversizing therefore adds operating cost instead of providing the safety margin it appears to offer.
Project Brief
Driving question. Which pump should the Okemont Water District install at its Marrable Road booster station, and what will the maintenance crew need to keep it running?
The client. The maintenance superintendent of the fictional Okemont Water District. She will take your recommendation to the district board. She wants a memo she can attach without rewriting.
The situation. The booster station lifts water from the low zone to the Okemont hill zone. Its single pump has failed twice this year, and the district has approved a replacement. The station runs about 14 hours a day for 120 days each summer. On 60 of those 120 days, demand stays at or below 480 gpm.
Constraints. Every one of these is firm. An option that misses any of them is out.
| Constraint | Requirement |
|---|---|
| Flow | Delivers at least 900 gpm at 120 feet of total head |
| Footprint | Fits the existing pad, which measures 9 feet by 12 feet |
| Installed cost | At or below $88,000, including pump, motor, starter, and labor |
| Electrical | 480-volt three-phase or lower, since the district's electricians are licensed to that level |
| Parts | Replacement parts available from a regional distributor within 48 hours |
The three options. All figures on these fictional option sheets were created for this project.
| Option | Description | Flow at 120 ft | Footprint | Installed cost | Power at the duty point | Parts lead time |
|---|---|---|---|---|---|---|
| A | One end-suction centrifugal pump, 60 hp, 480 volt | 1,050 gpm | 6 ft by 9 ft | $71,000 | 29 kW at 900 gpm, falling only to 26 kW when throttled to 480 gpm | 24 hours |
| B | One vertical turbine can pump, 50 hp, 480 volt | 960 gpm | 5 ft by 7 ft plus an 8-foot can | $86,500 | 26 kW at 900 gpm | 4 days, factory only |
| C | Two end-suction pumps in parallel, 25 hp each, 480 volt | 480 gpm each, 960 gpm together | 8 ft by 11 ft | $84,000 | 31 kW with both running, 15.5 kW with one running | 24 hours |
Other stated figures. The district pays $0.11 per kWh. The pad cannot be enlarged this year. The station has room for the piping any of the three options would need.
What you turn in. A constraint screening table, a two-page recommendation memo addressed to the superintendent, a one-page maintenance and training plan, and a six-minute briefing with two slides or one poster.
Milestones
- Session 1, screening. Write each of the five constraints as an inequality using a named variable. Then test all three options and mark each one viable or nonviable. Output: a completed screening table with the inequalities shown and one sentence per rejected option naming the constraint it missed.
- Session 2, comparison. For each surviving option, estimate the electricity used across the
120-day season and its cost, using the hours, the power figures, and the rate in the brief.
List three maintenance consequences of each option, such as the number of seals and bearings to
service, what happens during a failure, and whether a partial failure leaves any water moving.
Output: a one-page comparison that shows the numbers and states every assumption used. - Session 3, drafting. Write the recommendation memo and the maintenance and training plan. The plan must list at least six recurring tasks, and for each one name who may legally perform it at the district: a licensed electrician, a maintenance mechanic, a licensed distribution operator, or an outside contractor. Output: a complete draft of both documents.
- Session 4, briefing. Deliver the six-minute briefing to a panel playing the superintendent and two board members, then answer two questions. Output: the final memo, the final plan, and the delivered briefing.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Rubric
| Criterion | Emerging | Developing | Proficient | Advanced |
|---|---|---|---|---|
| Constraint screening | Constraints are described in words only, and options are not tested | Some constraints are written as inequalities, and screening is incomplete | All five constraints are written as inequalities and every option is correctly marked viable or nonviable | All constraints are written as inequalities, screening is correct, and the team names which single constraint each rejected option missed first |
| Comparison and evidence | Options are compared by opinion with no figures | Energy is estimated for one option, or assumptions are not stated | Seasonal energy use and cost are estimated for every surviving option with assumptions stated | Estimates are complete and the team explains how a changed assumption, such as fewer running hours, would move the comparison |
| Maintenance and scope of practice | The plan lists tasks without saying who performs them | Tasks are listed and some are matched to a trade | At least six recurring tasks are listed, each matched to the electrician, mechanic, operator, or contractor | Tasks are matched correctly and the team explains why one task cannot be assigned to district staff at all |
| Recommendation memo | No clear recommendation, or the memo restates the option sheets | Recommends an option but does not tie it to the constraints | Recommends one option in a memo organized around the constraints and the comparison | Recommends one option, states what it gives up against the rejected option, and names what would change the recommendation |
| Briefing and questions | Runs past time or cannot answer either question | Delivers the briefing but answers questions with restatement | Delivers within time, with a clear claim and evidence, and answers both questions directly | Delivers within time, answers both questions with evidence, and concedes accurately where the panel finds a real weakness |
Differentiation
Support
Give teams the five inequalities already written with the variable defined, so the first session is spent testing rather than formulating. Provide a worked energy example on a fourth fictional pump so the multiplication sequence of kilowatts times hours times rate is modeled once. Allow the memo to be one page with four required headings.
Extension
Ask teams to calculate the simple payback period between the two surviving options, dividing the difference in installed cost by the difference in seasonal energy cost. In the fictional figures given, the parallel option saves just under eight hundred dollars a season while costing thirteen thousand dollars more to install, so the payback runs past fifteen years. Have the team argue whether redundancy justifies that gap, and what evidence about past outages would settle it.
ELL supports
Pre-teach "duty point," "total head," "parallel operation," "installed cost," and "scope of practice" with a labeled drawing of a booster station showing suction, discharge, motor, and control panel. Provide a memo template with the four headings and one sentence frame for each. Allow the briefing to be delivered from a written script.
Extensions
Have teams call or email a local utility's maintenance staff and ask which of the two surviving designs the utility actually uses at its own booster stations and why, then add one paragraph to the memo reporting what they learned. A second option is to have teams write the purchase specification for the option they chose, listing what a bidder must supply and what the district will test before accepting the pump, which is the document the recommendation turns into once the board approves it.