Recycling of Plastics
Plastics are produced from mineral oil and, despite their low price, are a valuable product. In the words of PlasticsEurope (European Association of Plastics Manufacturers): «They are too valuable to be thrown away. » Essentially, almost all plastics are reusable. The best recycling solutions available are those for materials of a single sort, where different kinds of plastic are mixed the processes are more complex. Consequently, often the simplest and most economical way to dispose of the material is to incinerate it.
Feedstock recycling describes chemical and thermal processes by means of which monomers, gases or oils can be recovered. These raw materials can then be used for the production of new plastics. In contrast to mechanical recycling, feedstock recycling can also be used for mixes of different plastics. The disadvantage is the high expenditure of energy involved in such processes.
As the name suggests mechanical recycling is a mechanical process in which plastics are sorted, crushed, washed and processed into what is called regrind. It is most important that the processing should be clean and use just a single material. Where this is not the case quality declines and the regrind can only be used for technically less demanding secondary products.
The PET bottle is a typical representative of feedstock recycling.
In energy recovery plastic is used to produce a substitute fuel. The calorific value of plastics is similar to that of black coal or heating oil. Energy recovery is used in industry, in Switzerland above all in cement works. Energy recovery also takes place in waste incineration plants in the form of power production and utilization of heat.
The problem about the recycling of plastics is that it generally takes the form of downcycling. The reuse of the material means a reduction of the original quality. The regrind plastic produced in the recycling process is used for less valuable products such as park benches, bollards, watering cans and containers. In addition this processing often involves mixing with other materials. The new products created are thus eliminated from the cycle of pure materials.
Upcycling means the production of a new and more valuable product out of old things. This is not an industrial form of processing but an alternative strategy that is employed by designers and others. For example new satchels are produced from old truck tarpaulins, or flower pots out of yoghurt beakers. Solutions of this kind harbor enormous creative potential and produce an ecological and social profit. However, the way to waste incineration cannot be avoided, simply delayed.