IRES: Sargassum-Plastic Sustainable Solutions (SPlaSS) in the Caribbean

Michigan Technological University, Houghton MI

Investigators

Abstract

Around 2011, residents, tourists, and researchers began noticing unprecedented amounts of sargassum seaweed on and offshore of the southern U.S. coasts and Caribbean islands. Sargassum quickly began to disrupt fishing, tourism, nearshore ecosystems, and even caused health problems for populations exposed to rotting sargassum seaweed. Sargassum arrives on shore mixed with plastic trash and can be difficult and costly to clean up. An estimated 5-13 million tons of plastic enters the ocean each year, and sargassum blooms are estimated at over 20 million tons each year. While there have been increased efforts to track, collect, and create valuable products out of sargassum, research and development has vastly ignored the connection between sargassum and ocean plastics. This IRES project investigates plastic-sargassum interactions in the ocean and develops valuable products from sargassum-plastic pollution, such as concrete and composite lumber, for the building and construction industry. Simultaneously, this project trains U.S. students in innovation and international collaborations through mentored research experiences in the Dominican Republic. This research progresses through three of the most prominent challenges in creating valuable products from sargassum-plastic pollution: tracking, collection, and product development. One of the main challenges facing management of sargassum is tracking seasonal flows: when will the seaweed blooms reach shore, where will they arrive, and in what quantities? This project uses satellite and aerial images to map and measure sargassum flows and then correlates this data with plastic information taken from field measurements. Collection is usually slow and costly, as it is mostly performed manually and with small-scale equipment. This project designs and tests new methods for collecting and processing that are best suited to delivering sargassum-plastic material in the quantities and condition best suited for development of value-add construction and building products. Finally, product development ensures profitability and feasibility by designing technologies that do not require extensive preparation of sargassum-plastic waste. This project investigates the use of pyrolysis -a process that uses high temperatures to break down sargassum-plastic pollution- to upcycle sargassum-plastic wastes. Pyrolysis creates waxes, chemicals, and char that can then be used to make composite lumber and concrete. The development of pyrolysis as a feedstock agnostic recycling technique that results in high value products is considered of utmost importance for plastic recycling, since sorting, transportation and impurities are often barriers in the recycling industry. This research develops new methods and techniques to produce concrete and composite lumber products, which will help drive the economics for collection and management of harmful sargassum-plastic reaching US and Caribbean shores. Research is primarily conducted by U.S. collegiate student trainees; as such this project trains these students to be globally aware and internationally capable of collaborating and innovating to support the U.S. to remain at the forefront of science, technology, engineering, and mathematics. The student training program includes topics such as advanced research methods, science communication, and collaborating on international teams. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.