Maresme Circular installs a new optical sorter at the Mataró waste treatment plant to improve the quality of the recyclable materials recovered from the grey bin

The system will help ensure that recovered materials, such as plastic from water bottles, can be more reliably reintroduced into industrial recycling processes as secondary raw materials
The project, funded through a grant from the Catalan Waste Agency as part of the NextGenerationEU Recovery, Transformation and Resilience Plan, will prevent the emission of 609 tonnes of CO₂ equivalent and save 2,436 MWh of energy annually

Maresme Circular has installed a new optical sorter at the Maresme Integral Centre for Waste Recovery with the goal of improving the quality of recyclable materials recovered from the residual waste stream and convert them into new resources. This new equipment, based on computer vision and artificial intelligence technology, enables more precise identification and separation of materials that should not have been placed in the grey bin, such as transparent plastics from water bottles, plastics from shampoo or detergent bottles, paper and cardboard, and beverage cartons.

The system operates using computer vision technology which, thanks to cameras and smart sensors, detects the different types of materials within the waste stream. When it identifies a particular material on the conveyor belt, it activates a small burst of air that directs it into the corresponding compartment.

Optical sorter powered by computer vision technology / Maresme Circular

The installation of this new sensor will significantly increase the purity of the recyclable materials recovered at the Centre. For PET plastic—the type used in water bottles—it is estimated that the purity will rise from the current 82% to 92%; as for HDPE plastic—such as that used in detergent bottles—it is projected to rise from 71% to 85%; paper and cardboard will increase from 87% to 97%; and it is estimated that beverage cartons will improve from 85% to 95%. This reduction in impurities will enable recovered materials to be more reliably reintroduced into industrial recycling processes as secondary raw materials, while also reducing treatment and transportation costs for recyclers.

The new system will also prevent the emission of 609 tonnes of CO₂ equivalent annually thanks to higher-quality recycling, as well as an additional reduction of 381 kg of CO₂ equivalent annually resulting from the decrease in the transport of impurities. The associated energy savings are estimated at 2,436 MWh per year.

Bales of recyclable materials from the grey bin recovered at the Maresme Integral Centre for Waste Recovery / Marga Cruz – Maresme Circular

Waste separation at home: a priority

The recyclable materials recovered at the Maresme Integral Centre for Waste Recovery are of lower quality from the outset than those that residents properly separate at home and place in the appropriate bins. This is because waste mistakenly placed in the grey bin is mixed with other waste streams, especially organic matter, which in the Maresme region still accounts for approximately 30% of the residual waste stream. This mixture degrades the quality of materials such as plastics, paper and cardboard, and cartons, making them more difficult to recycle. The addition of the new optical sorter will allow these materials to be recovered more efficiently and at a higher level of quality, but this technological improvement does not replace the importance of source separation. Separating waste correctly at home remains the most effective way to achieve high-quality recycling and reduce environmental impact.

The installation of the new optical sorter involved an investment of €378,886.18, excluding VAT. The project, funded through a grant from the Catalan Waste Agency as part of the NextGenerationEU Recovery, Transformation and Resilience Plan, was awarded to Picvisa.