Sortation, or sorting, is the separation of collected waste into uniform fractions by material, polymer type, colour and quality. It comes after collection and before washing and recycling.
Sorting matters because different plastics do not mix when melted: a small amount of the wrong polymer weakens the whole batch. Waste is first split into materials such as plastic, paper and metal, then plastics are sorted by polymer, form (rigid or film) and colour. This is done by hand in manual sorting, by machines in mechanical sorting, or by both, at collection centres, MRFs and recycling plants. The sorted fractions are compressed by baling. The cleaner the sort, the higher the quality of the recyclate, and the more valuable its end use.
