Texas Tech University

Environmental Engineering Professor Receives Grant to Find Ways to Effectively Treat Landfill Leachate

Amanda Bowman

September 20, 2019

Jennifer Guelfo will look at the way per- and polyfluoroalkyl substances behave in landfills and how to prevent them from entering landfill leachate.

There are many chemicals that were once considered harmless, such as nicotine or asbestos, that have since been proved to be dangerous. One group of compounds, per- and polyfluoroalkyl substances (PFAS), have been manufactured and used in a variety of products and applications in the United States since the 1940s, such as firefighting agents, food packaging and commercial household products.

According to the United States Environmental Protection Agency (EPA), PFAS are very persistent in the environment and in the human body – meaning they don't break down and can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects, such as reproductive and developmental deficiencies and possibly cancer.

Jennifer Guelfo, an assistant professor of environmental engineering in Texas Tech University's Edward E. Whitacre Jr. College of Engineering, received a $500,000 grant from the EPA to see how landfill leachate – water that has percolated through municipal waste and leached out some of the waste constituents – contributes to the amount of PFAS in the environment.

"The overall idea of the project is to look at the occurrence and behavior of PFAS in landfills," Guelfo said. "There are products with PFAS that are disposed of in landfills. When it rains, water makes its way through the landfill and PFAS can be transferred from the waste into the landfill leachate. Some leachate is pumped, treated and released into the environment, but PFAS are not fully removed from treated effluent. Some of the leachate containing PFAS may percolate beneath the landfill through the landfill liner system, even though we try to prevent that with the way landfills are engineered. In either case, PFAS may end up released to the environment.

"We don't really fully understand how much landfills contribute to the amount of PFAS in the environment. So the goal of this project is to understand, which PFAS are in landfills? What happens to them once they're in landfills? Can we use some of the treatment techniques that people are doing research on right now to remove them from landfill leachate?"

Joseph Heppert, Texas Tech's vice president for research, is thankful the EPA has recognized the importance of Guelfo's research, not only for Texas, but also the U.S.

"We are grateful to the EPA for funding this study of the fate of PFAS in the nation's landfills," Heppert said. "Research of this type is critical for protecting the health of communities that might be affected by such pollutants. The opportunity to partner with the EPA in conducting this study is one of a very important example of how Texas Tech researchers are applying cutting-edge technology to solve challenging problems in service to the citizens of our state and nation."

Guelfo will study real leachate from landfills in the northeastern U.S. as well as artificial leachate she will create in the lab.

"Creating leachate isn't as easy as you might think," Guelfo said. "You start with water and you add different things to it that you might find in leachate, for example, metals, but leachate also changes over time. New leachate is much different than older leachate that's migrated through more of the solid waste column. Sometimes landfills actually pump their leachate and re-circulate it through landfills. A fraction might go to treatment and a fraction might get re-circulated, so the composition changes.

"We're going to have to try to pick what we think is most representative, and basically mimic different parameters like metals, inorganic ions and organic matter. We'll have to decide whether we want it to be more representative of a new leachate or an aged one."

Guelfo is the principal investigator (P.I.) on the project. Though she doesn't have any co-P.Is., she has three senior collaborators who will mentor her throughout the three-year study:

  • Danny Reible, the Donovan Maddox Distinguished Engineering Chair, Horn Professor and a professor of chemical engineering and civil, environmental and construction engineering;
  • Kurt Pennell, the 250th Anniversary Professor of Engineering at Brown University; and
  • Michelle Crimi, a professor and director of the Department of Engineering and Management at Clarkson University.

Guelfo also will receive help in the lab from Naveen Kumar, a postdoctoral research associate, and an environmental engineering doctoral student also will focus on this project.