William Tarpeh awarded MacArthur “genius grant”

Someday, waste will be wealth. That vision has long inspired William Tarpeh, an assistant professor of chemical engineering and a center fellow, by courtesy, at the Stanford Woods Institute for the Environment. The John D. and Catherine T. MacArthur Foundation recently awarded Tarpeh a 2025 MacArthur Fellowship in recognition of his pioneering work to turn wastewater into a source of valuable resources, such as clean water, fertilizer, and battery precursors.

“Turning wastewater pollutants into valuable chemical products provides exciting opportunities to realize circular economies and sustain our future,” Tarpeh said, describing his most recent Woods Institute-funded wastewater recovery project. 

“We are particularly excited about element-specific circular economies,” Tarpeh said. “Think a less leaky nitrogen cycle, or a more circular lithium cycle, or securing phosphate for fertilizers and battery precursors. Our main approach is electrochemical wastewater refining, which leverages electricity-driven reactions and separations to turn this ambitious vision into a low-energy, low-emissions reality.”

Read more about Tarpeh’s MacArthur Award

The MacArthur Fellowship, often called a “genius grant,” comes with an $800,000 prize. It honors creative individuals who advance bold new ideas. For Tarpeh, an assistant professor, by courtesy, of civil and environmental engineering in the Stanford School of Engineering and the Stanford Doerr School of Sustainability, that creativity has been fueled by early and sustained support from Woods, which has funded three of his key research efforts since he joined the Stanford faculty in 2018.

Tarpeh’s first Woods grant, awarded in 2019, developed an electrochemical process for recovering nitrogen and sulfur from wastewater to allow for water reuse and fertilizer production. It helped launch his efforts to recover nutrients and energy from waste streams using affordable, scalable technologies.

“I am grateful to Woods for helping fund some of my first ideas as a new assistant professor, and doing so in a way that helped build incredible collaborations that fueled our progress,” Tarpeh said. “Some of these have turned into National Science Foundation grants, exciting papers, and actual devices that are poised to be deployed on farms and at wastewater treatment plants”

Subsequent Woods-funded projects have expanded on that vision, supporting Tarpeh’s work in recovering and recycling nitrogen used in fertilizers to make agriculture more sustainable, and developing resins to filter contaminants out of wastewater and recover valuable products, among other efforts.

Water resource recovery work has deep roots in the Woods Institute. A 2004 grant led to DNA-based methods for diagnosing wastewater treatment plant issues. A 2009 grant helped develop a groundbreaking method to extract nitrogen from wastewater for reuse in treatment plants. Uncommon Dialogues held between 2008 and 2010 brought together Stanford faculty, regional water officials, and industry leaders to stimulate thinking about a test bed for energy-efficient water reclamation as part of a larger focus on catalyzing collaborative water reclamation and management efforts. Out of that grew the Codiga Resource Recovery Center, a facility on Stanford’s campus that enables pilot testing of promising technologies for the recovery of resources, such as nutrients and energy, from wastewater.

By supporting early-stage, high-risk ideas through funding programs such as Environmental Venture Projects and the Realizing Environmental Innovation Program, Woods has played a central role in advancing the innovative wastewater research of Tarpeh and others from lab-scale discovery to real-world application.

Tarpeh is also a center fellow at the Precourt Institute for Energy.