Career spotlight Grade 6 Careers & CTE
Designing a Membrane Plant: A Water Engineer Profile
A grade 6 career profile of an environmental engineer who designs a reverse-osmosis membrane addition to a drinking-water plant, covering the degree and license path.
Objectives
- Students will describe what an environmental engineer does when designing a reverse-osmosis treatment plant.
- Students will describe the college degree and license path into water engineering.
Vocabulary
- Environmental engineer
- An engineer who designs systems that protect people and nature, such as water treatment plants and projects that clean up pollution.
- Reverse osmosis
- Reverse osmosis cleans water by pushing it through a membrane with holes so tiny that salt and most other dissolved things cannot fit through. It can even turn seawater into fresh water.
Also: membrane, professional engineer license
Teacher overview
Some water problems cannot be fixed by an operator alone; they need a new part of the plant designed and built. That work belongs to an environmental engineer. This profile follows Aisha Korhonen, an engineer who designs a reverse-osmosis membrane addition for a fictional town's water plant. It explains the design work, the college and license path into engineering, and why membrane treatment costs more to run. A four-year engineering degree is one path into the water sector, alongside plant operations, certificate programs, and graduate research.
Career Profile
The problem to solve. Aisha works for a water utility in the town of Sable Ridge. The town's wells have turned salty, and new rules set a limit of 4.0 parts per trillion (ppt) each for two chemicals, PFOA and PFOS, which belong to a group called PFAS. The old sand filters cannot remove salt or PFAS. Aisha's task is to design a treatment step that can. Her plan uses reverse osmosis, often shortened to RO. In reverse osmosis, a pump pushes water against a membrane, a sheet with holes so tiny that water molecules squeeze through while salt and PFAS are left behind. The clean water passes on, and the leftover salty water is carried away.
A typical week. Aisha spends part of her time at a desk and part at the plant. At her desk she draws the layout, sizes the pumps and pipes, and checks that the design will make enough clean water for the town. She uses math to predict flow and pressure, since RO needs strong pressure to push water through the membranes. She also estimates energy use, because pushing water through membranes takes more electricity than older methods. At the plant she meets with operators to learn what they need, walks the site to see where the new equipment will fit, and checks the work as it is built. She writes reports and presents her plans to the town's leaders, who must approve the cost.
Getting there. Engineers usually earn a four-year bachelor's degree in civil or environmental engineering. Many go on to earn a master's degree in a water topic. To sign official designs, an engineer earns a Professional Engineer license, called a PE. Earning a PE takes passing two exams and working several years under a licensed engineer. This is a longer path than the operator path, and it centers on design and math rather than daily plant control.
Why it matters. Membrane treatment is powerful but costly to run. Seawater reverse osmosis uses roughly 11 to 15 kilowatt-hours of electricity per 1,000 gallons, while conventional treatment and delivery of local water use about 1 to 2. Towns choose it when they have no cheaper way to get safe water. On the coast, some cities treat seawater this way; the Carlsbad plant in California is the nation's largest and makes about 50 million gallons per day. The water sector needs new engineers as older ones retire, since about one-third of the workforce can retire within the next decade.
Student Handout
Discussion questions
- In your own words, explain how a reverse-osmosis membrane separates clean water from salt, based on the Career Profile.
- Name two things Aisha does at her desk and one thing she does at the plant.
- How is the path to becoming an engineer different from the path to becoming a plant operator?
- Reverse osmosis costs more electricity to run than older treatment. Explain why the town of Sable Ridge might still decide it is worth the cost.
From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.
Answer Key
- Answer: A pump pushes the water against a membrane full of tiny holes; water molecules fit through the holes and pass on as clean water, while the larger salt and PFAS particles are blocked and left behind in the leftover water.
- Answer: At her desk she draws the layout, sizes pumps and pipes, predicts flow and pressure, and estimates energy use (any two). At the plant she meets with operators, walks the site, or checks the work as it is built (any one).
- Answer: An engineer earns a four-year college degree, often a master's, and a Professional Engineer license after years of work and two exams, and the job centers on design and math, while an operator usually starts with a high school diploma, trains on the job, and passes an operator license exam.
- Answer: The wells are salty and face a stricter PFAS limit, and the old sand filters cannot remove salt or PFAS, so reverse osmosis may be the only way to give the town safe water; the higher electricity cost can be worth it when there is no cheaper safe option.
Differentiation
Support
Provide a labeled sketch of the reverse-osmosis step (dirty water, pump, membrane, clean water out, salty water out) beside the Career Profile so students can answer question 1 by pointing to the parts before writing.
Extension
Ask students to list, using only this profile, three reasons a town might choose reverse osmosis and one reason it might hesitate, then decide which side they find more convincing and explain why in a short paragraph.
ELL supports
Pre-teach "environmental engineer," "reverse osmosis," "membrane," and "professional engineer license" with short definitions and simple visuals. Allow question 2 to be answered as a list of short phrases rather than full sentences.