They have shown that marine plastic waste can be treated in the urban recycling system.

The separation of marine PET bottles (polyethylene terephthalate, one of the most common marine plastics) is effective and successful, according to a study by the UPV/EHU research group Materials + Technologies. In particular, researchers have analysed, from a practical point of view, the possibility of integrating coastal sewage into the urban solid waste management system.

In fact, unlike urban solid waste, marine waste does not yet have a systematised management system. Researchers have recalled that marine waste has a high degree of degradation, so the researchers’ first question was: Is this high degree of degradation an obstacle to the classification of marine waste in an urban waste management process?

To respond to this, they have used PET water bottles of the same brand, divided into two groups: the first has been left outdoors for nine months, and we simulate the conditions of a beach or rocky coast; the second has been submerged into the sea for the same time. The submerged bottles were found to undergo higher chemical degradation, while those on the coast and in the open air remained in a better state. Subsequently, the management of these materials in a treatment plant for urban solid waste was simulated and compared with the same non-degraded bottles, to see if the automatic separation equipment of these facilities would be able to identify and separate plastic bottles of marine origin.

For this purpose, tests were conducted with an optical separation system, that is, with a technology that automatically classifies the materials according to their composition. They demonstrated that it is possible to separate PET bottles of marine and urban origin in a joint process.

According to the researchers, this is a first step in an area with great development potential. In fact, they think that the more efficient and viable the management of this type of waste, the more the incentive for its use and, therefore, the interest in the collection from the sea will increase.