Temple Engineers Use Air Bubbles To Remove Water Contaminants

Md Saiful Islam, a graduate student from the College of Engineering, and Gangadhar Andaluri, assistant professor of civil and environmental engineering, are advancing water treatment technology that sustainably removes PFAS chemicals and microplastics from drinking water.

Water treatment plants devote significant resources to removing contaminants from our drinking water. PFAS, the so-called forever chemicals linked to cancer and other health issues, and microplastics can be especially difficult to filter out. But new research from Temple’s College of Engineering may someday offer a simple, sustainable solution, which relies on an unexpected ingredient: air bubbles.

Md Saiful Islam, a PhD student in the environmental engineering program, was selected as the 2025 Graduate Research Award Sustainability Program (GRASP) recipient from the Office of Sustainability to conduct research on combined removal technology for microplastics and PFAS. He is using air bubbles to create foam that captures contaminants and allows them to be easily filtered from water. Unlike existing foam-based treatments, Saiful’s approach can remove both PFAS and microplastics, and it doesn’t require toxic chemicals.

The technology was recognized with an Innovation and Collaboration Award from the Water Resources Association of the Delaware River Basin, and Saiful is beginning to attract interest from partners in the water utilities industry.

It all started while analyzing water collected by the University of New Hampshire. Saiful and his faculty advisor, Gangadhar Andaluri, assistant professor of civil and environmental engineering, found that most of the PFAS were concentrated in the foam at the water’s surface. They became interested in the mechanisms that resulted in foaming and wondered if the same phenomenon could be used to remove PFAS and microplastics. They then led several studies analyzing how PFAS and microplastics interact and coexist in water.

“PFAS have hydrophobic tails, meaning they are repelled by water,” said Saiful, who spent 10 years as a consultant on water contaminants before coming to Temple. “We thought if we could introduce air bubbles to the water, then the hydrophobic tail would be attracted to the bubble and get trapped on its surface. As the bubbles rise, they carry the interacted contaminants, PFAS and microplastics, and we can then remove the foam and the contaminants from the surface of the water.”

The approach removes contaminants without the use of additional toxic chemicals, which Saiful said makes it more sustainable than existing methods.

It is also remarkably efficient. The foam concentration makes up just 1% of the total filtered water, so when Saiful treats 100 gallons of water, he produces a maximum of one gallon of contaminated foam.

He then treats the remaining 1% of contaminated foam using a method called supercritical water oxidation, in which contaminants are destroyed by high temperature and pressurized water.

That same method, supercritical water oxidation, is already being used by few industrial water facilities, but as the sole method for removing contaminants, it requires significantly higher energy as well as greater capital and operational costs than Saiful’s method.

Another existing method utilizes granular-activated carbon technology to capture contaminants on the surface of carbon. However, this approach is carbon-intensive, which has its own issues.

“Carbon treatment itself is a challenge,” Saiful said. “And you’re not removing the contaminants. You’re just transferring them from one medium to another, leading to incomplete contaminants removal and the generation of secondary waste, so carbon management becomes another issue with this method.”

Saiful’s breakthrough comes at an opportune time. The U.S. Environmental Protection Agency is introducing new regulations in 2031, which establish maximum contaminant levels for six different kinds of PFAS in drinking water.

“Everyone is looking for sustainable ways to meet these new regulations,” Saiful said. He and Andaluri have partnered with the Valley Forge Sewer Authority, a local water utility company, which provides them with wastewater for experimental validation of the process.

Saiful has also conducted interviews with more than 20 water utility stakeholders to understand their real-world operational challenges and needs. Many of these stakeholders have shown strong interest in Saiful’s innovation, he said.

“We can easily integrate foam fractionation technology at the end of existing water treatment plant processes,” he said. “If existing water treatment plants decide to use our technology, they don’t need major renovations. But if you switch to other techniques, you would require significant modifications to the plant.”

Saiful demonstrated his technology during a Nov. 5 showcase at the College of Engineering. He and Andaluri are now working on optimizing the technology and testing it on different water sources, including the Schuylkill River and Atlantic Ocean.

As they continue to make improvements, they will work with Temple’s Office of the Vice President for Research to pursue patent protections for the innovation.

“People are already asking about our next plans, and how we can implement this technology in the field,” Saiful said. “It is a simple system, but it can have a profound impact.” - Jonny Hart