Graduate Profile

PhD student studying how urban wildfires impact the water supply

Jeff Zehnder — Tue, 24 Feb 2026 20:55:20 +0000

PhD student studying how urban wildfires impact the water supply Jeff Zehnder Tue, 02/24/2026 - 13:55

Jeff Zehnder

Bowden collecting water samples from a stream.

Mackenzie Bowden is shining a light on water hazards in the aftermath of wildfires.

“When people think about fire, water isn’t the first thing they consider, but when you look at events like the 2021 Marshall Fire and the 2025 fires in Los Angeles, there are all these synthetic compounds that get introduced to the water supply in runoff from burned homes,” Bowden said. “We want to know what that does for people downstream who drink that water.”

Three Minute Thesis

An environmental engineering student at the University of Colorado Boulder, Bowden has already earned accolades for her work, earning second place at the campus Three Minute Thesis Competition.

The event challenges graduate students to craft a three-minute elevator pitch for their complex—and sometimes difficult to make sense of—research in a way that even an everyday person could understand. Bowden was one of 11 presenters to take part in the competition last month.

“It’s very rare to have a dedicated audience listening to you talk about your research,” she said. “You spend all your time in the lab or writing papers, talking only to the niche audience in your field. This is about seeing how well I can discuss what I’m doing with other people.”

Fire Aftermath

Bowden came to 91��ý in the aftermath of the Marshall Fire, which destroyed over 1,000 homes. With a background in analytical chemistry, she began analyzing the complex compounds that result from fires at the wildland-urban interface.

“Risk assessment tends to look at specific chemicals in isolation, but chemicals don’t appear in isolation, they’re in mixtures. If you look for lead, that’s important, but what if the lead binds with things you aren’t looking for,” she said.

The ash and remnants of wildfires in forests and grasslands are comprised primarily of well-understood organic materials. With wildfires increasingly spreading to towns and cities, there is potential for more problematic pollution.

To effectively monitor those situations, Bowden has conducted hands-on research of the materials that comprise modern homes.

“I go buy construction materials like PVC pipes, fiberglass insulation, roofing materials, and burn them under controlled conditions so I can measure the organic and inorganic content of the ash as well as its toxicological potential,” she said.

Chemical Analysis

The analysis combines chromatography, mass spectrometry, and biological assays to identify resulting compounds, determine their quantities, and evaluate biological response.

“Samples contaminated by burnt PVC pipes were always more toxic than anything else, but when that burnt PVC was present with burnt wood, that toxicity was masked. It’s a prime example of how mixture interactions would have been completely misinterpreted by single chemical tests,” Bowden said.

Bowden will defend her dissertation next month. After graduation, she is seeking postdoctoral fellowships with an eye toward becoming a university professor.

“Environmental engineering is a very multidisciplinary field,” she said. “It pulls in environmental science, chemistry, biology, and ecology. It’s all these different puzzle pieces being fit together. I want to keep contributing and advancing the field.”

Bowden speaking at Three Minute Thesis

Mackenzie Bowden is shining a light on water hazards in the aftermath of wildfires. “When people think about fire, water isn’t the first thing they consider, but when you look at...

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Student designing greener buildings and a better future

Anonymous — Thu, 05 Sep 2024 22:03:07 +0000

Student designing greener buildings and a better future Anonymous (not verified) Thu, 09/05/2024 - 16:03

Jeff Zehnder

By analyzing formulas and construction blueprints, Jules Fischer-White is helping Americans build better green homes as a modeling engineer at Emu Passive Inc.

“It’s a super cool company. If an individual is going to build a house and wants it to be more energy efficient, we model it and give advice on how to improve their design,” Fischer-White said.

It is much more than simply suggesting better windows or adding insulation.

“We get plans from the architect, and I model the total floor area as well as internal net volumes of all the rooms, which gives us information for sizing the ventilation system,” he said. “We also look at the building envelope, which includes the windows, doors, and other boundary conditions. We geo-locate the project as well and include nearby trees and other shade sources so we can calculate how much sunlight will be entering each window in summer and winter.”

He began the part-time position midway through his senior year, as a chance to use what he has learned in the classroom to make the world a better place.

Fischer-White wrapped up his undergrad in May, but decided to pursue his master’s through the BAM program.

“I joined 91��ý in the spring of 2020, right before COVID. It took a while to get into the flow and meet people and be part of campus life and I want to enjoy my college years. In some ways it feels like I’ve only been here three years,” he said.

Drawn to science and math at a young age, Fischer-White had a unique path to 91��ý.

Although he is a Colorado native, his family moved to Thailand while he was still a toddler. He grew up there – and speaks fluent Thai – but their home was in a town without many opportunities for someone with a budding interest in STEM fields.

“We lived in an area that’s rated as one of the best retirement communities in the country, but there weren’t that many things to do for younger people, especially stuff in science and math,” Fischer-White said.

He returned to the United States for his junior and senior years of high school at a boarding school in Vermont.

“I’d never really had access to a chemistry lab or physics lab before. There were so many resources I had never seen. That was really exciting to me,” he said.

He decided he wanted to be an engineer, and the interdisciplinary nature of environmental engineering was particularly appealing.

Continuing to live in the United States for college made sense. While Thai universities offer engineering programs, Fischer-White said they are not accredited internationally, which would have limited his employment opportunities.

Although it had been 15 years since his family lived in Colorado, the state was still their home base, at least on paper, making 91��ý an easy choice.

Earning a master’s also offers Fischer-White the opportunity to learn more about another passion area: water and sanitation.

“I want to dive more into it,” Fischer-White said. “I love building science, but I also would love to work with Doctors Without Borders as a sanitary engineer. Every time they set up a hospital, they need engineers to deal with waste. It’s an area where I feel like I’ll always be able to sleep well delivering clean water to people.”

The environmental engineering graduate program offers multiple courses in water management, reuse, and sanitation. Fischer-White hopes to spend the 2024-25 academic year completing his MS before entering the workforce full-time.

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Grad student turning trash into cash

Anonymous — Tue, 09 Jul 2024 19:27:16 +0000

Grad student turning trash into cash Anonymous (not verified) Tue, 07/09/2024 - 13:27

Jeff Zehnder

Brooke Marten (left) and Prof. Sherri Cook following Marten's successful thesis defense July 1.

Brooke Marten (MEnvEngr’21, PhD’24) is engineering a better environment through high tech solid waste analysis.

Marten just completed her PhD in environmental engineering at the University of Colorado Boulder, focused on what happens to trash after it is carted off to the landfill – and ways to turn it into a valuable product.

“My focus is on resource recovery of the organic fraction of municipal solid waste – food waste and yard trimmings,” Marten said. “You can recover valuable material that can be marketed and sold.”

Her research and PhD thesis used life cycle analysis to evaluate different solid waste strategies including composting, anaerobic digestion and especially pyrolysis, a method of breaking down organic material in the absence of oxygen at high temperatures – typically above 500 °C.

“Implementation of the more common organic waste management strategies, like anaerobic digestion and composting, has been slow, so we wanted to look particularly at the use of a novel strategy, pyrolysis, which showed real potential,” Marten said.

An emphasis of Marten’s work is how turning waste into a useful product can also reduce environmental impact. Pyrolysis results in a solid called biochar that can be used as a landfill cover material. It avoids the need to use soil or woodchips and reduces landfill emissions.

Pyrolysis can also treat landfill leachate, formed when rainwater filters through buried waste, and recovers syngas, which can be combusted for energy production.

“I have a draw to recover resources from something people view as trash, flipping the narrative. This shouldn’t be a burden; it is an opportunity to recover something,” she said.

Conducting life cycle analysis models the full implications of these environmental actions, providing a more complete picture.

“Carbon footprints are on everyone’s radar, and the analysis looks at that, but it’s actually quite a bit more complex – for example, we also look at each strategies’ potential to cause algal blooms, form smog, and contribute to ocean acidification. If our plan helps in one area but hurts in another, we want to avoid that,” she said.

The analysis also focuses on dollars and cents.

This shouldn’t be a burden; it is an opportunity to recover something." - Brooke Marten

“We can’t recommend something that’s great for greenhouse gas reduction but is totally unaffordable,” she said.

The desire for such a complete analysis grew during Marten’s undergraduate years as a civil engineering student at the University of Wisconsin – Madison. There, she observed a campus Styrofoam and foam packing material recycling program and wanted to know if was as beneficial as hoped.

“They recycled Styrofoam, but to do it they were driving these trucks all around picking it up. I wanted to know if that made sense or if it should just be landfilled,” she said.

She learned about life cycle analysis, but did not have the knowledge necessary to conduct one as an undergrad. It eventually led her to 91��ý and Professor Sherri Cook, who is an expert in the methodology and would become her PhD advisor.

“It’s a very marketable skillset and I knew I had to go to grad school to do it,” Marten said.

Completing such analysis is resource-intensive. Marten developed computerized process models, adding variable after variable – waste mass, material composition, energy potential, and more, to present the most complete picture possible, as the ideal answer for one municipality may not work as well for another.

“Waste is so heterogeneous, and the solutions are not one size fits all. Some parts of the country really push collection of yard waste. Others emphasize foot scraps. That composition could change the answers,” Marten said.

Her PhD thesis, “Towards Sustainable Resource Recovery: Developing and Evaluating Novel Strategies for the Organic Fraction of Municipal Solid Waste,” is now complete and Marten successfully defended on July 1.

The next chapter of her life is with Pacific Northwest National Laboratory, where she has been hired as a sustainability engineer, a job rich in research and life cycle assessments.

“They work on a lot of novel concepts at national labs, and I love research,” she said. “I’m really excited about it.”

Brooke Marten is engineering a better environment through high tech solid waste analysis. Marten just completed her PhD in environmental engineering, focused on what happens to trash after it is carted off to the landfill – and ways to turn it into a valuable product.

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