Educational Activity Lets Kids Create a Clean-Water Plant on Their Own Tabletop

Teachers can engage students with help from a University of Colorado website filled with activities designed to promote careers in environmental engineering.

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The University of Colorado Boulder hosts a hands-on mini wastewater treatment plant activity at its online TeachEngineering Digital Library. It helps high school students learn how water is purified through a simple, step-by-step experiment.

The library has more than 3.4 million users around the world. The university provides educators with lesson plans, worksheets and a list of materials needed to create the mini-wastewater treatment plant, all at no cost.

The activity is part of the university’s TeachEngineering program, which since 2004 has promoted science activities to encourage students to pursue engineering studies and careers.

Meeting standards

The mini wastewater treatment plant activity is part of the TeachEngineering library of 1,600 activities for K-12 teachers. It contributes to Next Generation Science Standards, which are required by 20 states and being considered by 20 more. The standards encourage a curriculum that encourages students to pursue opportunities in science-related fields.

The university is partnering with a pilot program called e4usa that is assembling an Advanced Placement engineering program aimed at helping students who partake of the activities on the digital library to earn high school and college credits.

“Right now, environmental engineering is a very popular field for students because so many are passionate about making the world a better place,” says Dr. Mike Soltys, senior instructor at the university. “This is really opening up a lot of eyes to this career option.”

Wastewater activity

A video on the TeachEngineering site,, shows all the materials needed and describes how to create the miniature treatment. The materials cost about $40 and include a 2-liter clear plastic bottle with 2 liters of “wastewater” containing a mix of simulated contaminants:

5 grams (1 tablespoon) of coffee grounds

40 grams (2 tablespoons) of sand

15 grams (1 tablespoon) of vegetable oil

1 ounce (2 tablespoons) of liquid soap

30 grams (2 tablespoons) of all-purpose plant food

4 grams of small, brightly colored plastic beads

The students design and create a small working model of a filter system to simulate the stages of wastewater treatment. The mini plant filter system is housed within the plastic bottle, which is cut in two. The goal is to remove the contaminants while reclaiming them as valuable resources. 

The students add assorted amounts of the pebbles, gravel, cotton mesh and sand to the bottle along with the coffee filters and test the turbidity and pH of the simulated wastewater before and after it goes through the coffee filters. The whole experiment takes roughly two hours.

Soltys observes, “The activity is a quick introduction for the students on how they can improve water quality and how to use different materials to filter out different contaminants that might be in the water.”

To augment the activity, Soltys suggests that teachers contact their local utility to give a classroom presentation about wastewater treatment, or to set up a plant tour: “My experience is that utilities are more than happy to come to the classrooms, present and then look at the students’ experiments.”

The mini treatment plant experiment is funded through a National Science Foundation grant and some private donors. The university works with educators to make sure the activities in the digital library meet schools’ current needs. University staff members test all the activities and partner with schools to make sure all activities are appropriate for the ages posted on the site.

Remote learning

The library continues to remain popular with educators around the world, especially in the times of COVID-19; the activities lend themselves to remote learning. The participants have a discussion group where they can share questions and ideas; they can also contact university staff members with queries.

Soltys says, “If you want to be a superhero with the kids, engage them with hands-on activities. From my experience, they all comment on how much fun it is for them.”   


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