Plastics can be recycled mechanically or chemically. Mechanical recycling involves sorting, cleaning, granulation/shredding, drying, melting, extrusion and pelletizing (Ragaert et al. 2017). An alternative to mechanical recycling is chemical recycling, which produces plastic feedstocks that can replace virgin plastic feedstock (Thiounn and Smith 2020). If mechanical and chemical recycling are not available, energy recovery is seen as the next most environmentally favourable way to deal with non-recyclable or hard to recycle plastic waste.
Storing waste in landfills under inadequate conditions is still a very common disposal method in many countries. In addition, a large share of plastic waste is mismanaged in dumpsites (which can collapse), burned in the open, abandoned at recycling and disposal facilities, or released into terrestrial or aquatic environments.
From collection: Drowning in Plastics: Marine Litter and Plastic Waste Vital Graphics