Algae Cleanup of Microplastics in Midwest Waters Shows >90% Removal, EPA Takes First Step

Microplastics are found in soil, water, and even at high altitudes, prompting regulatory attention. In the Midwest, Science Friday's Kate Grumpke interviews local scientists about an algae-based method for removing microplastics from water. The algae, engineered to clump with tiny plastic fragments, can be recovered and recycled, with lab results showing impressive cleanup performance. The discussion also highlights ongoing local efforts to develop plastic alternatives and baleen-inspired filtration concepts, all within the broader context of wastewater treatment and environmental solutions.

Overview

The podcast examines microplastics and nanoplastics, their ubiquity across ecosystems, and regulatory steps such as the EPA's first move to regulate microplastics in drinking water. Through reporting from the Midwest, the episode centers on a lab breakthrough at the University of Missouri where engineered algae are used to capture and remove microplastics from water, potentially in systems like wastewater plants while also addressing nutrient removal.

"Microplastics are everywhere" - Kathleen Davis

Local Context and Field Observations

Kate Grumpke, senior environmental reporter for St. Louis Public Radio, shares stories from the region, including microplastics found in a cave near St. Louis that harbored endangered bats. The cave system tends to connect to the outside world, and flooding increases the influx of outside plastics, illustrating how microplastics migrate through connected environments and are carried by hydrological events.

The Algae Breakthrough: Mechanism and Paper

The episode details a Missouri lab led by a University of Missouri professor who engineered algae that are highly hydrophobic, mirroring the hydrophobic nature of many microplastics. The researchers demonstrated that the algae self-aggregate with microplastics and sink them to the bottom of the water column, enabling removal. A Nature Communications paper outlines the approach and suggests that the resulting algae-microplastic sludge could be recycled into new products. Lab results report the removal of more than 90% of microplastics in tested solutions, including the smallest fragments that are typically hard to filter.

"algae can self precipitate" - Dr. Suzy Day

Local Efforts and Broader Solutions

Beyond the algae work, the podcast highlights other Midwest efforts such as baleen-inspired filtration concepts at St. Louis University, where researchers imagine whale baleen-like fibrous structures to help plankton-sized materials, including microplastics, be filtered from water. Washington University is pursuing plastic alternatives and more sustainable materials, particularly focusing on fibers from clothing and textiles that contribute to microplastic pollution. The discussion frames these efforts as parts of a larger strategy to not only remove microplastics but also reduce their prevalence by offering alternatives to conventional plastics and improving wastewater treatment infrastructure.

"this is a great area to look at if you're looking for some hope" - Kathleen Davis

Future Deployment and Practical Considerations

Dr. Suzy Day discusses scaling the algae approach, including containment requirements for using a genetically modified organism and the concept of confined reactors at wastewater facilities. The idea is to grow algae under controlled conditions, using sunlight and nutrient-rich water to target microplastics while also removing excess nutrients such as nitrogen and phosphorus, thereby delivering multiple environmental benefits and potentially integrating with other water treatment workflows.

"it will be done in a confined environment" - Dr. Suzy Day

Impact, Challenges, and Takeaways

The podcast emphasizes that while the algae approach shows promise, it is not a panacea. Scientists view the results as a meaningful step forward, offering a tangible technology that can be refined, scaled, and integrated with existing systems. The host notes the presence of hopeful sentiment among researchers and the public health relevance of addressing microplastics in drinking water, while also acknowledging the need for careful regulatory assessment, long-term ecological impact studies, and robust infrastructure planning to realize real-world benefits.

"they're really hopeful. They're really excited about what they're working on." - Kathleen Davis