Sorting of packaging waste
After separate collection, packaging waste can be sorted.
Plastic is a complex material and is more appropriately referred to in the plural, “plastics”. Each plastic material (polymer) has its own chemical, physical, mechanical and functional properties, which make it ideal for specific applications. Consequently, recycled plastics are more likely to be used and therefore distributed if they can be traced back to a homogeneous polymer matrix or at least to a compatible matrix.
Many different polymers are used in the production of packaging. It would not be reasonable or appropriate to require citizens to sort various types of plastic. That is why heterogeneous plastic packaging waste must be carefully sorted after separate collection.
Corepla sorts all packaging waste collected by Italian municipalities and contracted organisations either directly in bulk or after a compacting/pre-cleaning phase. This crucial phase to prepare materials for recycling is carried out via a network of facilities located throughout the country, the Corepla Sorting Centres (CSS).
Having met the minimum authorisation, technical and management requirements set by the Consortium, these third-party waste recovery companies have signed sorting contracts with the Consortium. Corepla pays them a pre-established service fee applied nationwide to have collected plastics sorted by polymer/colour. Foreign fractions mistakenly sorted by citizens in the separate waste collection are also removed.
Originally, the material was transported on conveyor belts, and workers would visually spot the different types of packaging and sort them by hand. These days, less than 15% of the materials processed are sorted by hand. The remaining 85% are sorted automatically by machines called optical detectors. These devices use electromagnetic radiation to emit waves onto the material passing on the conveyor belt. The device determines a different wavelength and amplitude for each polymer. A spectrometer can be used to recognise which polymer is passing through and, using nozzles that blow compressed air, transport and sort the materials into homogenous groups. As a result only machine errors have to be corrected manually.
The sorting process produces various homogeneous types of semi-finished products that meet strict quality specifications. Although still considered waste and therefore governed by waste regulations, these products can be sold by Corepla:
- colourless PET bottles (mineral water, soft drinks, etc.)
- blue PET bottles
- PET bottles in other colours
- high density polyethylene (HDPE) bottles (detergents, soaps, etc.)
- polyethylene films (bags, bottle packaging, household appliance packaging, etc.)
- fruit and vegetable crates (which are not collected by the Consortium)
- mixed packaging (mainly rigid and flexible polyethylene or polypropylene).