Digital watermark moves closer to commercialization

AIM, the European Brands Association, and the Alliance to End Plastic Waste are working with the City of Copenhagen to conduct the semi-industrial test phase of a pilot project to test progress on the Digital Watermarks Initiative, also known as Holy Grail 2.0.

The developers are moving a step closer to precision identification and sorting of plastic packaging waste through digital watermarks, with the potential to transform the sorting and recycling process of plastic packaging.

Prototype sorting centre

Over the next four months, a prototype sorting detection unit will be installed at the Amager Resource Centre (ARC) in Copenhagen, where it will be tested using around 125,000 pieces of packaging representing up to 260 different stock-keeping units (SKUs). Engineers will test for several parameters including the speed and accuracy of the system, to ensure its ability to withstand the pressures of full-scale industrial operations.

Two machine vendors, Pellenc ST and Tomra, together with the selected digital watermarks technology provider Digimarc, are developing add-on modules for their detection sorting units, to be combined with existing NIR (near infra-red) sorters.

Both modules will be tested during the semi-industrial phase via trials at two different test locations. The first controlled tests using industrial-sized equipment and the Pellenc ST/Digimarc module are scheduled for October 2021 at ARC sortingcentre.

“The City of Copenhagen has a political ambition to become the world’s first carbon neutral capital by 2025. High quality plastic recycling that substitutes new production and reduces incineration is a key instrument to reach this goal. HolyGrail 2.0 has the potential to achieve this and we look forward to doing our part in the testing of the technology”, said Merete Kristoffersen, head of division, waste and resources, City of Copenhagen.

On shelves in 2022

If successful, digitally watermarked products could be introduced to store shelves in Denmark, France and Germany by the first half of 2022 for in-market demonstrations and industrial-scale trials. During this commercial test phase, consumers will buy on-shelf products with digitally watermarked packaging.

Used packaging will enter the waste stream after consumption. The sorting units will be placed in 5 different locations in France and Germany, including MRFs (Materials Recovery Facility), PRFs (Plastic Recovery Facility) and recycling plants.

This last phase is scheduled to run until Q3 2022 and a public report outlining the techno-economic analysis of the digital watermark technology for sorting of packaging waste will be issued.


Digital watermarks are imperceptible codes, each the size of a postage stamp. They cover the surface of a consumer goods packaging and carry a wide range of attributes such as packaging type, material and usage.

Used packaging is collected and scanned on the sorting line with a high-resolution camera which detects and decodes the digital watermark. The packaging is then sorted into corresponding streams, based on specified attributes including food, non-food or polymer types. This leads to more accurate sorting streams and higher quality recyclates to be channelled back into the plastic packaging value chain.

This milestone marks the second year of the HolyGrail 2.0 project. Since its launch in September 2020, it has grown to include over 130 participating companies and organizations across the complete packaging value chain. The pioneering HolyGrail 1.0 was facilitated by the Ellen MacArthur Foundation between 2016 and 2019.