Every summer, massive mats of golden-brown Sargassum seaweed wash ashore along the Gulf Coast. In small doses, the seaweed drifts in the open ocean and provides shelter for marine life, but recent overgrowth of the species has wreaked havoc.
Millions of tons pile up on beaches and rot, suffocating ecosystems, driving away tourists and releasing toxic gases like hydrogen sulfide. The trigger lies upstream, where agricultural and urban runoff dumps excess nitrogen and phosphorus into coastal waterways, feeding algal blooms and leading to massive marine “dead zones.”
Researchers in the UT San Antonio Margie and Bill Klesse College of Engineering and Integrated Design are tackling both issues — nutrient pollution and Sargassum inundation — in one circular solution.
Shalinee Kavadiya, PhD, assistant professor in the Department of Biomedical and Chemical Engineering, is leading a team that is transforming harvested Sargassum into 3D-printed, reusable filtration modules designed to catch runoff nutrients before they reach the ocean.
“The problems of Sargassum inundation and overgrowth, nutrient pollution, and waste management tend to be treated independently,” said Kavadiya, who is also a part of the Institute of Water, Research, Sustainability and Policy. “Our research connects them and addresses them all together with a sustainable manufacturing solution.”
Beginning September 2026, the project is supported by a three-year grant of $735,532 from the U.S. Environmental Protection Agency through the Gulf of America Program.
From seaweed to sea cleaner: The fabrication process
The process begins with Sargassum collected along the Texas coast.
Kavadiya and co-principal investigator Vikram Kapoor, PhD, Klesse Endowed Professor, Civil and Environmental Engineering, and Construction Management, transform the decaying seaweed into water treatment technology.
The team dries and powders the seaweed, then converts it into organic, inorganic and composite materials. These materials are then used to fabricate porous filtration units, which include a 3D-printed backbone and a coating of functional material that can bind with nutrients like phosphorus and nitrogen.
The modules are stacked with varying pore sizes, so the system traps physical sediment at the front, where water enters, and collects dissolved chemicals deeper inside.
“3D printing makes it easy and reproducible to fabricate filtration units while offering control over their physical form,” Kavadiya said, adding that the structures are easy to separate and recover from water after nutrient capture.
The design also supports one of the project’s goals: creating a filtration system that can be reused rather than discarded after one use.
A sustainable, circular design for long-term use
Traditional commercial stormwater filters rely heavily on single-use minerals that end up in landfills once saturated. The UT San Antonio team is developing a renewable and reusable alternative.
“As we keep using the filter, the coating may start to degrade,” Kavadiya said. “But the underlying lattice backbone is recyclable and reusable, so we can re-coat it and use it again for nutrient capture.”
The researchers will test the filtration system in the field to assess its efficiency and durability. This analysis will ultimately help coastal communities and government agencies evaluate the modules as a potential solution at scale.
By the end of the project, Kavadiya expects the team will “be able to tell how frequently you would need to replace the filter based on the water flow and what size filter works best for a given area,” among other logistical details.
“We are going to do an economic analysis to understand how this technology compares to the existing technology right now,” she added.
In the long term, Kavadiya hopes to explore ways to recycle the nutrients collected in her filters, which could potentially be reused as fertilizer in agriculture.
“We want to shift the focus from waste management to resource recovery. We are not just managing the waste, but recovering a resource that still has value,” she said.
