HolyGrail 2.0 and the digital recycling passport

Can a new digital technology help improve how packaging is sorted, thus increasing the quality of recycling and driving the circular economy? The HolyGrail 2.0 initiative aims to answer this precise question.

Digital watermarks are at the heart of this project; hidden in the colour print on packaging, they are invisible to the human eye and work in the same way as a barcode. US-based company Digimarc developed these digital watermark codes, which are integrated into existing print files via software, meaning companies do not need special colours or printing methods.

The invisible codes are no bigger than a stamp and can cover the entire surface of the packaging without spoiling the actual packaging design. The code is then captured by high-resolution cameras at waste sorting plants; based on the information it contains, the plant can then sort packaging waste into the respective material streams more effectively than is currently the case.

HolyGrail 2.0 emerged from the pioneering HolyGrail project, which was funded by the Ellen MacArthur Foundation from 2016 to 2019 and examined a number of approaches to improve recycling along the packaging value chain. Digital watermarks proved the most promising technology and were picked up by AIM, the European Brands Association, with the HolyGrail 2.0 initiative, which more than 120 international companies and organisations have since joined.

In September, these digital watermarks that allow for the smart sorting of packaging waste entered the next stage of testing in Copenhagen. Prior to that, machine manufacturers Pellenc ST and Tomra had teamed up with Digimarc to develop additional modules for their sorting plants, which can be combined with existing NIR (Near Infrared Reflectance) sorting devices. The first Pellenc ST prototype has now been installed at Amager Resource Centre (ARC), a sorting centre in Copenhagen, and is expected to achieve an ejection rate of more than 95 percent. In the coming months, the project team will conduct experiments with around 125,000 different types of packaging at the plant, all of which have been provided by HolyGrail 2.0 members. Henkel, for example, has contributed packaging for its Vernel and Pattex products to the current testing phase. The aim is to obtain further findings on how digital watermark technology can improve how PET bottles with perforated sleeves (Vernel) and PE cartridges for silicone sealant (Pattex) are sorted. For the testing phase to be considered a success, the Pellenc ST module now needs to recognise and sort packaging of different shapes and sizes that has been equipped with digital watermarks. The Tomra/Digimarc module is expected to be tested in Germany in late 2021/early 2022.

If both tests prove successful, packaging equipped with DW codes could be on shelves in Denmark, France and Germany by the first half of 2022, making their way into the “real” waste stream after use. Both prototypes would then be employed at commercial sorting and recycling plants under normal operating conditions as part of a large-scale pilot project. By the end of 2022, the HolyGrail 2.0 initiative aims to present a final report with all results.

But the “digital recycling passport” may do more than ensure efficient sorting and recycling processes; it also offers a range of options for packaging design as well as for processes in logistics, product control and retail sales, as the codes can contain a wealth of information: the GTIN (Global Trade Item Number), a unique, global identifier for articles, also known as the EAN code, has been integrated into the DW code, for example.