Did you know that Iowa has more wastewater treatment lagoons than any other state in the country?

That might seem like a dubious honor, but Sahar El Abbadi says that these lagoons can offer a low-cost, low-energy way of treating waste if the land is available. El Abbadi is a new assistant professor of civil and environmental engineering and a research engineer at IIHR—Hydroscience and Engineering (IIHR). 

“Lagoons are widely used throughout the country,” El Abbadi says. “But Iowa is sort of the epicenter.”

El Abbadi plans to study how much methane and nitrous oxide wastewater treatment lagoons produce. Predicting emissions can be challenging, she says, because lagoons vary widely in their design and operation. 

The local climate also plays a role. Iowa’s seasonal variations affect the production and release of greenhouse gases, while in areas such as California, the climate is much more stable year-round. 

The lure of physics

El Abbadi grew up in Southern California near Santa Barbara. She was a good student who enjoyed school across the board. She loved to read and write and even thought she might major in English when she attended college.

But when she took an engineering physics class, El Abbadi met a teacher who changed her trajectory. “He really inspired me to love physics,” she says. 

She liked it so much, she decided to study engineering physics when she enrolled at the University of California Berkeley as an undergraduate. In the summer after her first year of college, El Abbadi got a job in a physics lab working with lasers. “I really enjoyed what I was doing,” she says.

But it wasn’t quite enough. “I realize now what I loved was research and being in that research environment,” El Abbadi says. “I thought physics was very cool, but I wanted to solve problems that I could see day to day. So, I changed my major to environmental engineering science.”

She went to Stanford for graduate school and a postdoctoral fellowship, followed by a position at Berkeley National Laboratory. 

When she was applying for faculty jobs, El Abbadi saw an opening at the University of Iowa and IIHR. “I thought, ‘Oh, this feels like a good fit for my interests,’” she says. And all those wastewater treatment lagoons across the state? They aligned perfectly with El Abbadi’s research interests. 

Modeling greenhouse gas emissions

Before coming to Iowa, El Abbadi studied methods of accurately measuring methane. Her work validated methane sensors through controlled field experiments and used measurement data in modeling. “For example, while I was at Berkeley Lab, we did this big model of greenhouse gas emissions from wastewater treatment,” El Abbadi says.

El Abbadi also studied upstream electricity use associated with chemical production in wastewater treatment. The model combined several datasets from the Environmental Protection Agency and the Department of Energy to get an estimate for the country.

As she was building that model, El Abbadi discovered that the data on direct measurement of gases produced onsite was not sufficiently representative. In this sector, she says, wastewater treatment plant operators who wanted to reduce their carbon footprint usually focused on reducing their energy requirement. Solutions included producing biogas onsite or adding solar panels.

And while that served an admirable goal, it missed the larger problem. “Very recently, we’ve realized that energy is less of a contributor than methane and nitrous oxide emissions,” El Abbadi says.  

Following the data

The data on gas emissions from wastewater treatment plants are quite sparse, and El Abbadi wants to change that. “We need a lot more, and we really need a lot more for lagoons because that area is very data-poor right now,” she says. “That’s what I’m excited to do.”

She wants to understand how variations in lagoon operation and construction can affect gas emissions. The first step, El Abbadi says, is to make sure we have tools to accurately measure and represent what is happening. 

“We then use those to understand, okay, how are these systems behaving?” she says. “Once we understand that, we can look for patterns. Are there different operational styles that are associated with fewer emissions?” 

Several years down the line, her research goal would be to find ways to reduce emissions, El Abbadi says. “And then, can we verify that we’ve reduced them with these measurement techniques we’ve developed?” 

New questions, unexpected answers

El Abbadi says she’s excited about the work and sharing it with her students. “I love learning. I love research. I love exploring new questions. I think I love the process,” she says. “Working with students is really motivating, and I love seeing them learning how to become a scientist and a researcher.” 

She’s also excited about working with IIHR colleagues such as Craig Just, who shares her interest in wastewater treatment. Just, who is the Donald L. Bently Professor of Engineering and an IIHR research engineer, focuses on ensuring that wastewater treatment processes meet discharge requirements while also improving the energy efficiency of lagoons. 

“Craig’s amazing,” El Abbadi says. “He shares my excitement about wastewater treatment.” 

Their work complements each other. “We’re thinking about these same systems, but he’s tackling it from this direction, and I’m thinking about greenhouse gas emissions.”

She’s excited to get to work and see where the data take her. “You never know — things always end up coming together in ways you don’t expect,” El Abbadi says. “That’s what’s great about research.”