Post-consumer plastic scraps recovery and recycling

Post-consumer scraps are plastics coming from kerbside, from street and sometimes from landfill, collection.
This means what follows:
Sorting, doesn't matter or automatic is compulsory because you'll get everything together with the scraps you are supposed to deal with.
For some materials it is "only" important while for some other it is compulsory.
Post-consumer plastics should go all the way through the entire process of separation by means of sink-float tanks and sometimes hydrocyclones, to washing, sometimes pre-washing, rinsing and drying. (for more information go to machinery section)
After all this, you may not have what you're expecting if your target is 100% purity.
In plastic recycling, like any other business, quality pays, but it should be a balance between costs and results.
One example for all is aluminum into PET bottles scraps; if you're getting old bottles with lots of aluminum caps and rings, you should provide for an electrostatic separator and a final metal detector to remove it, no question.
But if you have an aluminum ring once in a while are you sure you want to buy a 70,000$ automatic electrostatic separator ? (that doesn't remove 100% of aluminum anyway).
The same concept applies to machinery: we can put everlasting platinum paddles on centrifuges and you'll never replace them but are you prepared to spend half a million for this ?
Back to post-consumer scraps, specially before starting, be sure of what you'll get as raw material.
If you know the contamination, doesn't matter which, it will be easy to remove but if you will have everything, be prepared to get a low quality material at the end or, your choice, to spend a lot of money for a damn complicated system.
And good luck.