Karl Linden recognized as Distinguished Professor at campus ceremony
Karl Linden, chair of CU Boulder’s Department of Civil, Environmental and Architectural Engineering and the Mortenson Professor in Sustainable Development, has been named a Distinguished Professor, the highest faculty honor awarded on the CU system’s four campuses. The recognition was presented to Linden and five others by Chancellor Justin Schwartz at the University of Colorado Board of Regents meeting on Feb. 6.
“When I came to CU Boulder 20 years ago, I was attracted by the collaborative spirit, focus on environmental sustainability and the amazing students this university was able to attract,” Linden said. “The colleagues I have been able to work with, the support from administrators and the creative and aspirational students that I have been able to mentor, have all enabled my successes. Being named a Distinguished Professor is a direct result of the incredible people I have been able to work with in Colorado.”
CU Distinguished Professors are tenured faculty members who demonstrate exemplary performance in research or creative work; a record of excellence in promoting learning and student attainment of knowledge and skills; and outstanding service to the profession, the university and its affiliates. Including this year’s seven honorees, only 160 Distinguished Professors have been named since the title’s establishment in 1977.
Advancing the field
Linden’s career has focused on innovative ways to improve water quality and water treatment. He’s known as an expert in ultraviolet light disinfection systems, now used by many municipal water systems.
He currently serves on the World Health Organization (WHO) Water Quality Technical Advisory Group. As a faculty member, he has taught hundreds of students in water and wastewater treatment, water and sanitation in developing communities, and graduate courses in water reuse and advanced treatment. He has authored more than 260 technical papers and has been honored with many high profile awards, too numerous to mention them all.
In 2023, Linden was honored with the Lifetime Achievement Award at the International UV Association (IUVA) World Congress, hosted in Dubai. During the event, the IUVA president called upon those who have worked with Linden, been his student or read his papers to stand.
"It was one of the sweetest moments of my career," Linden said at the time. “Almost the whole room was standing. It was overwhelming and humbling."
Most recently, he received the American Water Works Association’s 2025 A.P. Black Research Award, which honors outstanding contributions to water science and supply, and appeared on the cover of the organization’s journal.
Linden has also been recognized as an elected Fellow of the American Association for the Advancement of Science (AAAS) “for distinguished contributions to the field of water treatment engineering, particularly for using ultraviolet light for pathogen disinfection and abatement of organic contaminants in water reuse.” During a Fulbright fellowship, he researched solutions to water pollution in rural and First Nations communities in Nova Scotia, focusing on the water quality challenges faced by those living in remote areas, including those without reliable access to safe running water or conventional sanitation.
During the COVID-19 pandemic, Linden and his researchers identified a specific wavelength of ultraviolet light that is effective at killing the virus and is safe for use in public places like concert halls and airports.
In 2020, he won the Borchardt-Glysson Water Treatment Innovation Prize and was named the Clarke Prize Laureate for outstanding achievement in water science and technology. In 2014, he was named the Water Reuse Foundation Person of the Year.
Early inspiration and education
Linden grew up in New York City. After being exposed to the environmental sciences in middle school, he decided to pursue a degree through Cornell University’s environmental engineering program in the College of Agriculture and Biological Engineering. While there, he learned how to drive a tractor and spread manure, which he said was “quite unique for a New York City kid.”
Linden left Cornell midway, not seeing the connection between his math and physics classes and his desire to protect the environment. Several years later, a serendipitous reading of a New York Times article about a Cornell professor, Bill Jewell, who purified water by growing plants in a constructed wetland, brought him back to Cornell. Inspired by Jewell’s class in biological waste management and a research position in his lab, Linden went on to work for one of the lab’s spinoff companies before pursuing a master’s degree and a PhD on UV disinfection at the University of California Davis. Before coming to Colorado, he was a professor at University of North Carolina Charlotte and Duke University.
“I think a lot about the people and places that have influenced my career and set me up for success and greatly honor my past mentors,” Linden said. “The greatest testament to my successes is not how many publications or projects I have been a part of but the extent to which I have enabled the success of others–my colleagues and students–and to set them up to do great things for protecting public health and the environment. “