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Mafalda de Freitas at the entrance of HPU's Center for Marine Debris Research (CMDR), located in central Honolulu.
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Plastic waste collected from across Hawai'i to be sorted for recycling efforts.
HPU's Center for Marine Debris Research (CMDR) has launched the state’s first and only marine debris Plastic Recycling Research Facility (PRRF), pioneering efforts to transform hundreds of thousands of pounds of plastic waste collected from the Pacific Ocean into long-life infrastructure products. This pioneering initiative aims to mitigate environmental damage and create durable products that could revolutionize local infrastructure, including construction materials for critically needed affordable housing in Hawai‘i.
Since relocating its operations to the Kalihi warehouse site in June 2024, CMDR has hauled in and processed over 227,000 pounds of marine debris, largely derelict fishing gear, including ghost nets and floats. Most of it is swept in, through swirling currents, from the North Pacific Garbage Patch where it is then collected by partners on various neighbor islands or by the Hawai‘i Longline Association and other commercial fishers through the Bounty Project.
Mafalda de Freitas sorts through plastic waste in HPU's Center for Marine Debris Research.
“These plastics drift from across the Pacific, accumulating in the North Pacific Gyre and eventually snagging on Hawai‘i’s fragile coral reefs before washing up on the shores,” said HPU Environmental Scientist and CMDR Megaplastic Program Director Mafalda de Freitas, M.Sc. “No Hawai‘i-based fishermen use the type of trawl nets we find; this debris is overwhelmingly foreign, underscoring the global nature of this issue.”
Up to twice a year, collected debris stored at partner sites on Kaua‘i, Maui, and Hawai‘i Island is transported in large shipping containers to CMDR’s warehouse. Volunteers, including HPU students, meticulously sort the debris by type and polymer. The center plans to install plastic recycling machinery to convert this debris into usable products in partnership with local businesses.
CMDR has collaborated with First Star Recycling in Omaha, Nebraska, to test converting fishing nets into 100% recycled plastic lumber – with the plan to bring the technology to Hawai‘i. This sustainable lumber can be used for decking, fencing, picnic benches, and more, significantly reducing Hawai‘i’s reliance on imported materials and products.
The team is also looking to explore innovative forms of manufacturing, including large format 3D printing, to increase technical skills and capabilities in the local community. Most importantly, the team seeks to create products that can be embedded in construction and offer promising solutions for addressing Hawai‘i’s critical shortage of affordable housing.
"We’re turning a major environmental problem into a tangible solution," explained de Freitas. "Our goal is to produce products locally, sustainably, and durably, enhancing our community’s resilience and self-sufficiency, especially when it comes to building housing."
In addition to recycled lumber, CMDR has partnered with a Kaua‘i-based contractor to develop innovative construction technologies such as “spider ties,” interlocking scaffolding structures that simplify concrete wall construction. This advancement holds the potential to dramatically reduce construction costs compared to other forms of masonry while embedding and retaining carbon from the plastic inside structures.
“We want to continually experiment with new product formulations,” said de Freitas, mentioning future test ideas include combining recycled plastics with natural materials. “Every successful product brings us one step closer to a circular economy.”
Notably, CMDR helped to pioneer an effort to incorporate recycled plastics into local roadways through the “Nets-to-Roads” project. This initiative incorporates shredded marine plastics into asphalt, creating road pavement that is more sustainable and diverting the marine debris plastic from incineration.
For the debris that cannot be recycled, CMDR partnered with the Nets-to-Energy Program, in partnership with Radius Recycling, POP Fishing, and Marine Supply and Covanta – H-Power, that incinerate the debris for electricity for the City and County of Honolulu.
“One issue we are facing right now at our current location is the need for additional space,” de Freitas shared. “If we can find a bigger location on the harbor, we can accept more plastics, get heavy lifting machinery that will help us work even faster and harder to help create a sustainable, renewable solution to the marine debris crisis in Hawai‘i. If anyone out there can help, please reach out!”
De Freitas can be reached via email at: mfreitas@hpu.edu.
For more information on HPU’s efforts and other CMDR’s projects, go to www.hpu.edu/cmdr.
