Crystalline Cloth: Modeling Water Treatment Filters
Cheesecloth swatch attached to wooden skewer with paper clip used as weight.Copyright 2019 Courtney Kehler, Rice University RET
Water filtration is a key engineering concept, and in this activity students become environmental engineers as they model membranes and membrane treatments to remove scaling during water filtration. Using cheese cloth to represent a simple membrane, students soak their “membrane” in a supersaturated salt (or sugar) solution and measure how much salt (or sugar) crystallizes on their cloth. They then research and analyze different treatments they can apply to their “membranes” to reduce the scaling (crystal growth). They apply and test their chosen treatments and then hypothesize which treatment method best prevents scaling on their “membrane.”
Water treatment are some of the most important technologies for the preservation of life. Environmental engineers work to create more efficient methods of water treatment in extreme situations, where if a system goes down, it would spell disaster for the humans there. One of the current best technologies is using membrane distillation to remove harmful or unwanted substances from water to make it drinkable again, however scaling on the membrane can increase the cost if left untreated. Engineers are currently working on ways to prevent the scaling from growing in the first place, delaying or hopefully even preventing the need to bring the water filtration system down for maintenance. Engineers work to develop water filtration devices that can be used in the aftermath of natural disasters where access to clean water isn't available.
After this activity, students should be able to:
- Think and outline design iteration suggestions.
- Understand the different steps of the engineering design process.
- Identify supersaturated solutions.
- Identify and discuss the differences between treatment options.