Author: Heidi Jeter

For years, Wisconsin farmers have applied biosolids—a byproduct of wastewater management — to their fields. The process reduces the need for commercial fertilizers, conditions the soil, and reduces the amount of biosolids going into a landfill.

Unfortunately, biosolids may be a major source of per- and polyfluoroalkyl substances (PFAS). These hazardous chemicals are used widely in household products and manufacturing, and they accumulate in biosolids.

Is Biochar a Solution to PFAS Leaching?

Five years ago, UW-Green Bay faculty began investigating whether land application of biosolids would result in PFAS leaching into groundwater. They received funding from the Freshwater Collaborative to partner with faculty and students from UW-Madison, UW-Platteville and UW-Stevens Point to investigate the issue.

“Not only did the grant provide funding to do the research, but the project was a learning experience in how to collaborate with faculty at different universities,” says Michael Holly, an associate professor at UW-Green Bay who specializes in agricultural waste management.

The team confirmed that use of biosolids can result in PFAS leaching at concentrations hazardous to human health. They also learned that biochar — a charcoal-like substance made by burning organic material such as forestry waste — may mitigate contamination. As part of the project, undergraduates from the four universities tested woodchip-based biochar to determine its effectiveness in adsorbing PFAS from soil.

The results were published by the American Chemical Society in January 2024.

The Freshwater Collaborative awarded a second grant in 2023 so the team could test biochar filter media on a working agricultural field. Holly and his colleague Kpoti Gunn, an assistant professor at UW-Green Bay, partnered with a local farmer who has been using biosolids on his fields. The research team installed moisture sensors and soil water sampling tools on his fields last summer.

“The first year, we observed the fields without the application of biochar,” Gunn says. “The goal this year is to prepare the field along with the farmer, apply biochar, and compare the results.”

Water samples collected from the field are sent to UW-Milwaukee to test PFAS levels. Holly and Gunn are collaborating with Yin Wang, associate professor at UW-Milwaukee, who recently received a two-year grant from the U.S. Department of Defense to identify a more efficient approach of removing PFAS from water.

Students Receive Water-Quality Training

Andrew Votis, a senior at UW-Green Bay, has worked with Gunn for the past year and a half. This spring, he is helping to set up and implement the crop plan for the research plot. The research has provided professional training for his future career and also has personal meaning.

“My wife and I run a dairy farm north of Green Bay in the Coleman-Peshtigo area, so my background made me a natural fit for the project,” he says.

Votis will graduate in summer 2025 with a degree in Environmental Engineering Technology, and he appreciates the practical skills he’s developed while conducting undergraduate research at UW-Green Bay.

“My work with Dr. Gunn has strengthened my ability to communicate with various groups, manage a team, as well as increased my understanding of the intricacies of research projects,” he says.

Jonna Rosenthal participated in the research last summer as part of the Freshwater@UW Summer Research Opportunities Program, also funded by the Freshwater Collaborative. Rosenthal is a senior at Smith College in Massachusetts where they have studied the effects of ocean acidification and salt-water contamination. They wanted to work on freshwater systems and were particularly interested in emerging contaminants such as PFAS.

“It was incredibly rewarding to collaborate with the faculty at UW-Green Bay,” they say. “I attend a small liberal arts school, so I had no experience with scientific work at a research institution. It was amazing to have access to analytic equipment and other esteemed scientists with whom I could collaborate.”

Rosenthal graduates in May 2025 and will begin work as an environmental scientist with AECOM, a global infrastructure consulting firm. They will research groundwater contamination.

“This work includes testing and monitoring sediments and groundwater, a skill that I developed during my collaboration with Dr. Gunn,” they say.

The project has already trained 13 undergraduates, and two graduate students are conducting research for their thesis. Another Freshwater@UW Scholar will join Votis on the project this summer.

What they learn could identify practical solutions to PFAS leaching — and give farmers a cost-effective tool for protecting groundwater near their fields.

Written by Heidi Jeter, Freshwater Collaborative.

Wisconsin-based Sadoff Iron & Metal Company has offered scrap metal recycling for more than 70 years. It collects non-ferrous metals and ferrous scrap, auto salvage, electronics recycling, and other materials at multiple sites in Wisconsin and Nebraska. Sadoff then provides ISO-certified recycled metal to steel mills and local foundries.

The company prides itself on its sustainable practices, but it has a costly challenge. When rainwater falls into the metal collection containers, it becomes contaminated by oils and other fluids on the metals. Sadoff pays by the gallon for the contaminated water to be hauled away and treated before being safely released into the environment.

Could there be a way to treat the water on site so it would be clean enough to meet sanitary requirements for discharging it into the city sewer system? In 2022, Sadoff teamed up with UW Oshkosh faculty and students to research solutions.

“The collaboration between a local university and industry is an exciting adventure,” says Gary Griessmeyer, Sadoff’s environmental compliance manager. “We are in the scrap industry not chemistry or biology. Students help us learn while they learn.”

Pilot Research to Test Solutions

A grant from the Freshwater Collaborative of Wisconsin provided funding for Associate Professor Marcel Dijkstra to hire three undergraduate students to conduct pilot studies to test various processes of contaminant removal.

Dijkstra says the goal is to develop a cost-effective way to separate oil, cutting fluids and particulate matter containing heavy metals from the stormwater collected in scrap metal containers. This would allow Sadoff to clean the water on site – saving them money and reducing their carbon footprint while protecting the environment.

The Sadoff partnership is one of the Water Technology Enterprise projects at UW Oshkosh. These projects, funded through a larger Freshwater Collaborative grant, foster new research partnerships between the university’s Environmental Research and Innovation Center (ERIC) and external companies. Dijkstra notes that companies often don’t have the time or in-house expertise for smaller research projects. Having students work on them is cost effective and provides real-life experience to the students.

“This isn’t a class project,” he says. “It brings the educational component to a completely different level.”

Tyler Peskie, a UW Oshkosh undergraduate, says working directly with an industry partner was an eye opener in terms of career possibilities. He graduates in May 2025 with a degree in environmental engineering technology.

“The first benefit of working on this experiment is that it gives me possible employment opportunities for more waste-related jobs,” he says. “Secondly, it benefited the university … it puts a lot more emphasis on research and application for industrial use.”

Tim Sommer, who graduated from UW Oshkosh in December 2023, notes that many companies in the area work closely together, so experience working as a partner with a company can lead to further job opportunities. He secured a job as a consulting environmental scientist after graduation. Now he’s a corporate environmental engineer at Green Bay Packaging. He says having this project on his resume got his foot in the door.

“It is crucial to seek out experience outside of the classroom,” he says. “This is where many ‘soft skills’ are learned and many networking opportunities can be found.”

Creating Ongoing Partnerships

The students have finished the pilot research funded through the grant, and Dijkstra is continuing to work with Sadoff to refine the processes. He incorporates the project data into his classroom activities, and students enrolled in his class tour the Sadoff facility. The most recent tests are promising.

Griessmeyer is pleased with the progress and would encourage other business to partner with universities on research.

“When people think about water, they think about agriculture and phosphorus. They don’t think about other businesses that need help,” he says. “Even if we don’t get to the end game, I think it’s something that we really can put it in our quiver for now. And as technology gets better, we could pull it back out.”

For more information about working with faculty at the UW Oshkosh ERIC, contact (920) 424-3148 or eric@uwosh.edu.

Written by Heidi Jeter, Freshwater Collaborative.