From pollutant to potential pot of gold?
Marquette becomes a research site for a national center seeking solutions to the problem of too much — and too little — phosphorus.
By Tracy Staedter
“It’s the problem nobody is talking about,” says Dr. Brooke Mayer, associate professor of civil, construction and environmental engineering.
She means phosphorus, a chemical element with the symbol “P” that is vital to life and critical for crops. Unfortunately, there’s way too much of it polluting lakes and rivers from agricultural runoff as well as from wastewater discharge. At the same time, natural sources of phosphorus are being depleted, making scarcity a long-term threat to food supplies.
These dueling problems are serious enough that the National Science Foundation is making phosphorus a high priority and establishing a $25 million national center, Science and Technologies for Phosphorus Sustainability, or STEPS. Marquette is one of eight partner institutions in the STEPS Center, which is led by North Carolina State University.
Mayer and other STEPS investigators will pursue a “25-in-25 vision,” she says. In 25 years, the partners aim to enable a 25 percent reduction in human dependence on mined phosphates as well as a 25 percent reduction of the amount of phosphorus that leaches into soils and water resources. Not only will science, research and innovations from the center help enhance food security, they will also improve the environment.
“That’s a really huge impact, and we think we can do it because we’re bringing together so many diverse researchers from across many fields and disciplines and institutions to actually be able to start tackling it,” says Mayer.
Too much and not enough
Mayer points out that the majority of the world’s mined rock phosphorus is extracted for use by farmers as a crop fertilizer. But about 80 percent of that P is lost to runoff from rains or melting snow, contributing to environmental threats such as algal blooms in lakes and rivers that lead to unsafe drinking water and impair aquatic life. In a world where so much phosphorus is wasted, it’s ironic that natural sources are limited, she writes. The majority of the reservoirs of minable phosphorus exist in just four countries, including China, which has one of the largest deposits and declared in July 2021 that it was banning exports at least through June 2022.
Mayer and her STEPS colleagues advocate for a circular P economy to address the chemical’s shortages and excesses. It involves removing and recovering phosphorus from municipal wastewater, agricultural runoff, environmental waters or soils and reusing it for agriculture. To that end, researchers representing 28 distinct disciplines, working from the molecular to global scales, will develop the science and technologies needed to improve phosphorus management.
For her part, Mayer will conduct materials-scale research and will also serve on the center’s leadership team as co-director of education and human resources. Using techniques inspired by nature, Mayer is leading a team to engineer systems featuring proteins that naturally attach phosphate. The idea is to put these phosphate-binding proteins onto a surface that, when used to filter water or wastewater, could capture phosphorus. She and her colleagues are also studying different forms of phosphorus to better understand their prevalence, molecular interactions with other chemicals or materials, and their fate in environmental and human systems.
In her education and human resources role, she will help train undergraduate students, graduate students and post-doctoral researchers from a range of disciplines who are interested in addressing phosphorus-related challenges. These researchers will benefit from deep disciplinary training in addition to engaging in convergence research (merging the expertise of widely disparate fields of knowledge, ideas, approaches and technologies to stimulate innovation and discovery).
Mayer says the center’s multidisciplinary, convergent approach to this project should have a “quantifiable, measurable, successful impact” in what she calls a “waste-to-resource gold mine.”
