William Tarpeh, an assistant professor of chemical engineering at Stanford University, has been named a 2025 MacArthur Fellow by the John D. and Catherine T. MacArthur Foundation. The fellowship, which includes an $800,000 award distributed over five years, recognizes individuals for creativity and the potential for future advances in their fields.
Tarpeh, who also holds courtesy appointments in civil and environmental engineering, was honored for his work developing energy-efficient and scalable techniques to recover valuable molecules from wastewater. His research focuses on designing devices and membranes that can sort molecules by their charge and volatility, enabling the extraction of useful substances from waste streams.
Current projects led by Tarpeh include recovering ammonia from wastewater—where it is typically a pollutant—and repurposing it for agricultural fertilizer. He is also working on methods to extract lithium from used batteries, allowing the metal to be reused. Tarpeh envisions technological advances that could eventually render the concept of wastewater obsolete by turning waste into resources.
“I am honored to be included in the MacArthur community of leaders committed to understanding and improving our world,” Tarpeh said. “This award is a testament to my community – the students and postdocs who took a chance on a new lab with a unique mission, my mentors who sharpened my skills, my colleagues who inspire me with creativity and dedication, and my family and friends for their endless support. I am excited to continue the work of redefining wastewater and creating circular, sustainable methods for improving quality of life while protecting the environment for generations to come.”
Jennifer Widom, the Frederick Emmons Terman Dean of the School of Engineering at Stanford, commented on the award: “I’m thrilled to see Will Tarpeh’s creativity and impact recognized with this prestigious honor. Will’s work turns the idea of ‘waste’ on its head, finding ingenious ways to recover and reuse valuable resources with the potential to transform global sustainability. This MacArthur Fellowship is a well-deserved recognition of his achievements and reflects the spirit of problem-solving and ingenuity that drives Stanford Engineering.”
Tarpeh is also affiliated with Stanford’s Precourt Institute for Energy and the Stanford Woods Institute for the Environment. The MacArthur Foundation selected 22 fellows in 2025 from various disciplines in science and art.
This announcement was first published by the Stanford School of Engineering.
