Madison Gilster grew up along the Snake River of southern Idaho, a meandering channel that carved canyons and left-behind bends like giant horseshoe tracks filled with water.
The Twin Falls area — where she joined high school theater productions, edited her school newspaper and fell in love with math and science — is heavily agricultural, an industry that uses a lot of phosphorous as fertilizer.
Phosphorous can also be a pollutant and like many water bodies, the Snake River is at the receiving end of much phosphorous runoff.
At University of Idaho, Gilster, a junior studying chemical engineering, is learning to extract phosphorous from water to re-use it as part of a research project in the lab of Associate Professor James Moberly.
“I am really interested in sustainability, and this project looks for ways to potentially recycle environmental phosphorous,” she said.
Making hydrogels
The research focuses on creating a gelatinous material, called hydrogel, that is made of mostly water. The gel holds bacteria that absorb phosphorous and allows it to be extracted from water, either from wastewater treatment plants or natural systems like lakes, ponds and rivers.
“Once we create a gel that picks up phosphorous, it can be removed from the water and the phosphorous can be recycled,” Gilster said.
The trick is creating gels — and the phosphorous-grabbing microorganisms that live in them — that can withstand tough environmental conditions while also remaining environmentally friendly.
Gilster spent last summer experimenting with these biodegradable gelatinous materials that support these microorganisms while also being durable enough to remain intact under environmental conditions.
Because it’s a major nutrient that natural systems often lack, phosphorous is among the main ingredients of agricultural fertilizer. When excess phosphorus leaks into waterways, it can cause super fertilization, or eutrophication, resulting in excess algae growth. This over-abundant growth can lead to depletion of oxygen from waterways killing animals such as fish and aquatic insects. Some algae are also toxic to animals or people that swim in, or drink, the contaminated water.
Removing phosphorous from natural systems to prevent eutrophication is just one of the benefits of creating bacteria-supporting gels. Finding a sustainable way to re-use phosphorous is another benefit.
“Our innovative strategy aims to create a sustainable system for phosphorus biomining, advancing both environmental protection and resource recovery,” Moberly said.
By creating phosphorous-grabbing gels in the lab and testing their viability and stamina — whether they can capture phosphorous and withstand the rigors of their surroundings — Gilster’s work could result in sustainably harvesting and re-using the excess phosphorous from Idaho’s waterways and wastewater plants.
Although municipal wastewater systems contain significant amounts of phosphorus, and a good place to use the hydrogels, most of wastewater phosphorous is lost to downstream waterways due to limitations in current wastewater treatment technologies, Gilster said.
I really want to get more girls involved in STEM.
Madi Gilster
Undergraduate in chemical engineering
Looking forward
The new system developing in Professor Moberly’s lab advances both environmental protection and resource recovery, she said.
“The information Madi collected this summer will be used to direct further research into these soft gelatinous materials,” Moberly said.
Gilster, a first-generation college student, opted to attend U of I because of its strong reputation as a STEM and research school. When she visited campus as a high school student, she was smitten by the guides running the campus tours.
“I love to talk, and I thought, I can do that,” she said.
She has been a U of I tour guide for two years in addition to immersing herself in outreach such as the annual STEM Fair and Engineering Expo and the Society of Women Engineers.
“We coordinate events, for kids,” she said. “I really want to get more girls involved in STEM.”
Gilster and her team of student researchers will continue designing and testing different biodegradable polymer hydrogels this year.