Heller, who attends Kettle Run High School in Virginia, got her idea for the filtration system a few years ago after learning that local water sources in her area were contaminated with PFAS and microplastics.

Microplastics, defined by the National Oceanic and Atmospheric Administration as plastic particles smaller than five millimeters, are an increasing environmental concern, according to Brighter Side of News. Each year, between 10 million and 40 million metric tons of plastic waste enter the environment. A Stanford University report warns the figure could double by 2040 without intervention. Microplastics have already been detected in more than 1,300 species.

At the time, Heller household relied on advanced filtration systems that required frequent membrane replacements, with no government subsidies available to offset the costs. "It inspired me to design a filter without the use of membranes, to decrease the costs and maintenance needs associated with water filtration," she told Smithsonian Magazine.

Mia Heller, an 18-year-old student at Kettle Run High School in Virginia, U.S. Photo from Heller's LinkedIn

In spring 2024, Heller developed the initial concept and later refined it through five prototypes, achieving a working version by summer 2025.

Her system avoids traditional membrane-based or chemical-heavy methods. Instead, it uses ferrofluid, a liquid containing magnetic particles, to attract and capture microplastic fragments. The latest version removes 95.52% of microplastics while recycling 87.15% of the ferrofluid used in the process.

"The result is an affordable, low-waste filtration system without the use of a solid membrane," Heller said.

Her work was recognized at the 2025 Regeneron International Science and Engineering Fair, the world’s largest global science competition for high school students, where she received a $500 award.

Matthew J. Campen, a toxicologist at the University of New Mexico in Albuquerque, described the system as a "really great idea" for a high school project, adding that its performance could improve with further engineering investment.

However, he noted that questions remain about how the captured microplastics are disposed of and whether the process leaves behind other pollutants. He also raised concerns about scalability, noting that even if the system works effectively, it must be viable for wider use.

Heller acknowledged these limitations, particularly the high cost of producing ferrofluid at scale. For now, she sees the system as suitable for individual households, with a compact design that can fit under a standard kitchen sink.

"I would love to eventually bring it out to market," she said. "I think that would be something that would be really interesting."