Today's KNOWLEDGE Share :New study finds ocean plastic could be recycled in urban waste systems

Today's KNOWLEDGE Share

In response to the millions of tons of marine litter, mostly plastics, floating on the oceans, the need to manage this waste effectively is more urgent than ever. Faced with this reality, the UPV/EHU’s Materials + Technologies research group decided to take the first step.

Classifying Marine Waste as Urban Waste:

We assessed a practical approach: the possibility of integrating plastics collected from the sea into the urban waste system. This study, which is part of a PhD thesis, explores the possibility of managing this waste efficiently in current urban recycling infrastructures,explained Cristina Peña, lecturer in the Department of Chemical and Environmental Engineering at the Faculty of Engineering, Gipuzkoa (UPV/EHU) and author of the work.

Unlike municipal solid waste, marine litter does not yet have a systematized management system; it is managed on a very ad hoc basis and within the framework of very specific projects. “It is important to bear in mind that this waste, having been at sea, has a level of degradation that is significantly different from, for example,a bottle deposited in a yellow container under normal conditions.So, our starting point and key question was precisely this:

Automatic Separation of Marine Plastics Such as PP and PE:

In this work, we used identical PET plastic water bottles of the same brand to assess the effects of various environmental conditions. We divided the bottles into two batches: the first batch was left in the open air for nine months, simulating exposure on a beach or rocky coast, and the second batch was submerged in the sea for the same period. We saw that the submerged bottles underwent increased chemical degradation, while those exposed to the open air on the “shore” remained in a better state.This approach allowed them to analyze how the degradation process varies according to marine conditions and how each type of waste responds in different environments.

Then they “simulated how these materials would be managed in an urban solid waste treatment plant” by comparing them with the same bottles that had not undergone degradation to see if the automatic separation equipment in these plants would be able to identify and separate the plastic bottles of marine origin.

“To find out, we conducted tests using an optical separation system, a type of technology that automatically classifies materials according to their composition, and saw that the effectiveness of separating the bottles of marine origin, both those exposed to the open air and those submerged in the sea- was very high, comparable to that of bottles from urban waste.

Source: University of the Basque Country/www.polymer-additives.specialchem.com