Final testing stage for HolyGrail 2.0

Digital watermarks could play a key role in the future when it comes to packaging recyclability. They are invisible to the human eye but carry a wealth of information. The HolyGrail 2.0 digital watermarking initiative aims to implement the technology for large-scale sorting of post-consumer waste, with plans for a pilot market in France. The final stage of testing is now under way.

The binding EU-wide targets for recycled plastics are approaching. When it comes to complying with the requirements planned from 2030, sorting packaging waste more successfully and accurately will be a key tool for obtaining high-quality recycled materials. This is exactly where the HolyGrail 2.0 initiative comes in. The pilot project set out to prove the technical feasibility of digital watermarks for sorting as well as the commercial viability of the business model on a large scale. The initiative is promoted by the European Brands Association (AIM) and the Alliance to End Plastic Waste and supported by more than 160 well-known businesses.

Digital watermarks are codes the size of a postage stamp that are imperceptible to the eye, cover the entire surface of a consumer goods packaging solution and carry a variety of attributes. As soon as the packaging enters a waste sorting system, the digital watermark is detected and decoded by a high-resolution camera. After this, the various items of packaging should be sorted into the corresponding streams with high speed and accuracy based on the properties that are transmitted.

The HolyGrail 2.0 project is divided into three stages. At the first stage, the prototype of a recognition system for the digital watermark was developed. The second stage in 2021 involved a semi-industrial test run with more than 100 products in Europe. During the third stage, the digital watermark will now be tested under real market conditionsin three test markets:Denmark, Germany and France.

The initiative has now entered the final testing stage. Two industrial-scale recycling trials are planned to complete this third phase, demonstrating how accurately the technology is able to detect, sort and offload the packaging material labelled with digital watermarks. PP films from PepsiCo and flexible LDPE material from Essity and P&G are being used in the test runs. The sorting tests are taking place at the Hündgen Entsorgung waste recovery plant in northwestern Germany. At the same facility, a three-month sorting trial will also start for digitally watermarked hard plastic packaging produced by several of the HolyGrail 2.0 initiative’s member companies, before being introduced to the Danish and German markets. Machine manufacturer Pellenc ST and tech company Digimarc have developed two prototypes for this purpose and installed them on Hündgen Entsorgung’s commercial sorting system.

One of the member companies, the Aldi Group (consisting of Aldi Süd and Aldi Nord) has teamed up with Digimarc and Wipak to print the invisible codes on its packaging in preparation for the third stage of testing. In partnership with plastic packaging specialists Greiner, the suppliers have ensured that 18 different kefir and yoghurt varieties from Aldi’s own brand Milsani have been equipped with watermarking technology. These products can already be found at Aldi shops in the German market.

At the same time, a new working group has been established as part of the project to set up a pilot market in France in 2024. To date, seven member companies have joined forces to introduce the technology to the French rigid HDPE packaging market. In the coming months, companies including Henkel, L’Oréal and P&G will be adding digital watermarks to a significant portion of their HDPE packaging range for the French market. Once used by the consumer, the collected post-consumer waste will be taken to Veolia’s PlastiLoop facility in Brenouille, France, where the system developed by Pellenc ST and Digimarc is designed to separate the watermarked non-food HDPE stream from the non-watermarked packaging waste. A special sorting test for granules will then be carried out, with the streams to be divided into detergent and cosmetic streams and then processed with the aim of developing fit-for-use rHDPE packaging for detergents and cosmetics.

If successful, this pilot market will supply further proof that HolyGrail 2.0 technology is ready for use – not only from a technical standpoint but also from a commercial point of view.