The first step to integrating ocean plastic into urban recycling

The need to address the millions of tonnes of marine debris (mostly plastic) floating in our oceans and effectively manage this waste has never been more urgent. Faced with this reality, the Materials + Technology Research Group at UPV/EHU decided to take the first step.

“We evaluated the practical approach of potentially integrating plastics collected from the ocean into urban waste systems. This pioneering research, part of a doctoral thesis, We will explore the possibility of efficiently managing this waste with infrastructure,” says Lecturer in the Department of Chemical and Environmental Engineering at the Gipuzkoa Faculty of Engineering (UPV/EHU) and author of a paper published in the journal Waste Management Bulletin. One Cristina Peña explained.

Unlike municipal solid waste, marine debris does not yet have a structured management system. It is managed on a very ad hoc basis and within the framework of very specific projects.

“It is important to keep in mind that this waste is floating in the ocean and has a very different level of decomposition than a bottle stored in a yellow container under normal conditions. The starting point and key question for the UPV/EHU material + technology study was: Can marine waste be classified into municipal waste management processes based on its level of degradation? Amaia Mendoza, a researcher with the group, points out.

“In this study, we used identical PET plastic water bottles of the same brand to assess the effects of different environmental conditions. The bottles were divided into two batches. The first batch was left outdoors for nine months. It was left alone to simulate outdoor exposure. The second batch was submerged at sea for the same period of time, but the bottles exposed to the open air on the “shore” remained in better condition, while the submerged bottles suffered more chemical deterioration. I understand. ”

This approach allowed us to analyze how the decomposition process changes depending on ocean conditions and how each type of waste reacts in different environments.

The researchers then simulated how these materials would be managed in a municipal solid waste treatment plant. They compared the plastic bottles with the same bottles that had not deteriorated to see if the automatic separators at these plants were able to identify and separate the plastic bottles. Marine origin.

“To confirm this, we conducted tests using an optical separation system, a type of technology that automatically sorts materials according to their composition. The effectiveness of the separation was confirmed when the water sank into the sea (both in exposed bottles and in bottles exposed outdoors), and the concentrations were very high and comparable to those in bottles from municipal waste. ” Mendoza said.

“These results demonstrate that processing of marine bottles at these plants is feasible and can be successfully implemented. The state of decomposition is critical in determining the feasibility of subsequent recycling. ” said the UPV/EHU researchers.

The study’s authors say, “This work demonstrates that PET bottles of marine and urban origin can be separated in a collaborative process, making an important advance and a first step in an area with great potential for development.” “We have established this,” he said. “It also paves the way for municipal waste treatment facilities to consider automated separation of other plastics, such as polypropylene and polyethylene, found in marine debris,” Mendoza added.

The UPV/EHU team emphasizes that this study aims to assess the potential of upgrading marine litter by making it attractive as a usable raw material. “If we can find practical uses for these materials and promote the development of industry, their collection will also become attractive.The more efficient and viable the management of this waste, the more “There is a greater incentive to use it and, as a result, a greater effect,” said Peña.