What is plastics traceability in the recycling process?

In order to reach sustainability goals, plastics need to be traceable throughout the recycling process. For recycled plastics (like rPETcomplex infrastructures and processes are required to maximise its potential, and our goal is to make sure not even the tiniest amount escapes.

These processes have high demands in terms of quality, including demands of traceability. But do you really know what plastics traceability in the recycling process is? Let’s take a quick look at the main concepts.


There are several ways to recycle plastic. Today, these are principally the following:

  • Chemical recycling: This process breaks the plastic back down into molecules (pyrolysis), the smallest part of their structure. The resulting simple structures (monomers) allow us to start from scratch and form new polymers. This method is particularly used with materials that cannot be recycled mechanically, especially PET, polyamide (PA) and PS.
  • Energy recovery: This process is great for types of plastic that cannot be recycled in other ways. They are used to obtain energy and it is estimated they could provide 8% of the energy needed for a country like Spain.
  • Mechanical recycling: This is the most relevant process in terms of plastics traceability in recycling and the one we are going to look at in detail. In the mechanical process, plastic is recycled and processed it so it can be returned to the production chain. This contributes to the circular economy, which is essential for a sustainable production chain.

The circular economy is a way of producing goods that reduces waste to a maximum, sending as much of it as possible to be converted into raw materials. This means we can avoid using virgin plastic and close the circle to ensure materials have many useful lives.

SP Group has been working towards a circular economy that also involves our clients, and it is here where our Tray2Tray project fits in. We are actively involved in managing the packaging waste produced by our clients. The materials we supply are collected and reintroduced into our production process. However, this project would collapse without traceability.


By ensuring traceability in the plastics recycling process, we are guaranteeing that the plastic produced in the process has the desired quality. However, this is very difficult when we are handling large amounts of waste that might break down during the process. Nevertheless, technology seems to have found an answer to the problem.

Chemical-based bar codes are currently in development. This means that a special electronic reader can detect any amount of plastic, whatever its size, that is not where it should be in the recycling process. It is also able to detect plastic in poor condition, even at molecular level.

This powerful tool is combined with blockchain technology to ensure accurate information without the need for third-party intervention, providing visibility of the whole supply chain. This technology is being used to ensure the traceability of plastics in the recycling process, not only to ensure each material can be located at all times, but to guarantee it is in perfect condition for reintroduction into the production cycle.


In the 1970s, identification codes were created to involve consumers in the traceability of different plastics during the recycling process. The Möbius loop (the triangular three-arrow recycling symbol we are all familiar with) contains a number from 1 to 7. Each number corresponds to the type of plastic the packaging or container is made of.

As each material had different characteristics, this code tells us  which materials are the most easily recyclable and helps us decide what to buy. The most easily recyclable materials are numbers 1 (PET – Polyethylene terephthalate), 2 (HDPE – High-density polyethylene), 4 (LDPE – Low-density polyethylene) and 5 (PP – Polypropylene).Take a look at our News section and Blog to find out much more about our advances in recycling techniques and processes, and the development of compostable and biodegradable materials. Follow us to discover how we are working towards sustainability through innovation.

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