On Tuesday, high school junior Mariah Freeman watched water drip through a filter she designed and constructed.
“We’re going to take the filter we’ve made, and we’re going to pour that water through it, and then retest the water in the new bottle,” Freeman explained.
Freeman and her classmates in Cheryl Esslinger’s Earth and Environmental Systems class at Rhinelander High School were simply trying to filter vinegar out of the water and balance its acidity.
The students wanted to know whether their inventions will filter out anything at all. Vinegar is the first step. The ultimate goal is devising a filter for per- and polyfluoroalkyl substances (PFAS).
“In between those two cotton rounds, we have activated charcoal. The activated charcoal is supposed to help filter out the PFAS in the water,” Freeman said, pointing out the parts of the filter.
This summer, elevated levels of PFAS, a water contaminant with health risks, was found in a Rhinelander municipal water well. High levels of PFAS have led to the city to shut off two wells.
Plenty of drinking water professionals are working to solve the PFAS problem in Rhinelander and across Wisconsin, and those adults could provide a long-term solution.
But a way to supply clean drinking water could also come from teenagers in Esslinger’s class. The science teacher dreamed up the project.
“PFAS was found in our Rhinelander water, and the well was shut down,” Esslinger said. “I thought, wow, this is a big thing.”
The issue soon turned into a class project for her four sections for Earth and Environmental Systems.
“We said, ‘Let’s do a filter, and make a filter that could be so inexpensive that everybody could have one,’” Esslinger said.
Right away, Freeman was on board, becoming one of the first in the class to come up with a design.
“I drew out an idea before pretty much anyone else, so I was really into this. It was really interesting,” she said. “I wanted to prove that even though I’m a female, I can make a water filter, too.”
Freeman’s filter is cheap. The materials cost 22 cents, she figures. On Tuesday, it was at least somewhat effective in filtering out vinegar.
But Freeman takes the most pride in the entire class doing tests on something that’s mostly of her own design.
“A lot of the guys were like, ‘Oh yeah, this is going to be so cool. We’re going to be the winners.’ When Ms. Esslinger addressed that my group with my design won and we were going to be creating my water filter, I was like, ‘See, girls can do this, too. Girls have the brains,’” Freeman said.
Other class sections are using coffee filters and rocks to purify water.
No matter how well any of the filters work, Esslinger said they won’t be the finished product.
“Once we find out which one actually works the best in all four classes, then we’ll do a redesign again,” she said. “That’s how engineering works.”
As Esslinger’s classes work through filter improvements, hoping to eventually test on PFAS itself, the project is being judged on a national level.
It’s already a state finalist in the Solve for Tomorrow contest, a $3 million competition sponsored by the electronics company Samsung.
“Really, it’s designed to get students out of the classroom and into their communities and really tackle an issue in their community using STEM skills,” said Michele Mosa, the Senior Manager of Corporate Citizenship at Samsung Electronics America.
Each year, Mosa sees a spike in different areas of interest for projects.
“I know this is a hyperlocal issue for Rhinelander High School, but throughout the nation, we’ve seen an uptick, this year in particular, in students wanting to tackle water quality issues,” Mosa said.
Next month, Esslinger will learn if she and her classes are state winners, which would earn them $15,000 in technology and equipment and keep them eligible for a $100,000 grand prize. The five grand prizes also include a trip to Washington, DC to present their projects to members of Congress.
But the real-world effect on students might be just as valuable as any prize they could win.
“It would be great if we actually created a PFAS filter, but I think having the students think about this, and what it takes, and the importance of clean water, [with] young people getting involved in making the change and seeing how we can solve a problem,” Esslinger said. “I think that’s the most important part.”
If an effective, inexpensive PFAS filter does come out of this classroom, there’s a good chance Mariah Freeman will play a major role.
“It’s not some adult in Rhinelander. It’s us, as kids, working on this,” Freeman said. “Something does need to be done, and the fact that we contributing to this, that’s really cool to me.”
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