Collected bottles are first sorted by material (PET, HDPE, PVC, etc.), then they are baled to reduce volume and ensure transport cost-effectiveness, and finally they are sold to reclaimers.
Bottles collected through a deposit scheme are sorted at the retailers. This can be done either manually or by sophisticated reverse vending machines.
Bottles coming from drop-off or kerbside collection schemes are taken to local sorting centres where the bottles are sorted by resin types, and maybe by colour, using high speed Near Infra Red (NIR) or X-ray technology linked to an ejection system. In some facilities operators still hand-pick PET bottles from a sorting line using simple features to identify the material. UK research reports manual sort rates of up to 100kg per person per hour.
With proper training and supervision this system can produce a high quality output.
Independent research carried out by the US Environmental Protection Agency reveals that automated systems can help saving about 25% of costs.
After sorting, bottles are compacted into bales, reducing volumes by up to a factor of 10.
