Mondi trials digital watermarking to separate waste

HolyGrail 2.0 launched

Postage stamp-sized watermarks on the packaging, which are not visible to the naked eye, make it possible to sort the material into specific waste streams effectively. Photo - Mondi

Mondi has joined forces with AIM, the European Brands Association, and other partners across the value chain to prove the viability of digital watermarking for sorting waste at scale. According to the press release, the HolyGrail 2.0 initiative has the goal of assessing whether this pioneering digital technology can enable better sorting and higher-quality recycling rates for packaging in the EU, thereby driving the circular economy.

Mondi was a founding member of the original Pioneer Project HolyGrail, facilitated by the Ellen MacArthur Foundation. Over 85 partners across the value chain are working together to refine and commercialize this concept, with Mondi continues its active role in trialing the innovative technology, it said.

Postage stamp-sized watermarks on the packaging—which are not visible to the naked eye—make it possible to sort the material into specific waste streams effectively. Conventional sensor technologies (for example, near-infrared spectroscopy) cannot reliably identify multi-material packaging, so they can end up as contaminants when recycling mono-materials.

Mondi says, with this new technology, it becomes possible to separate materials more accurately and generate new waste streams, which then can be recycled with enhanced recycling technologies. These digital watermarks also provide other opportunities. For example, consumers can use a smartphone app to find details about the packaging and how to recycle it, and brand owners can add product details.

Graeme Smith, head of Product Sustainability for Flexible Packaging and Engineered Materials, explained, “As members of the Ellen MacArthur Foundation’s New Plastics Economy, we were part of the initial team to bring the Pioneer Project, HolyGrail, to life.

At Mondi, we believe packaging should be sustainable by design and we see the need to improve the sorting and separation of packaging waste as part of a circular economy. Digital watermarks have the potential to make this a reality. Improved recycling will increase the value of packaging waste, driving higher collection rates and making it a valuable commercial resource for the future.”

As HolyGrail 2.0 progresses, Mondi is well-positioned to contribute to its success by validating digital watermarks with partners along the value chain. According to the press release, Mondi will be conducting full-scale industrial trials with key customers shortly.

HolyGrail 2.0

The Digital Watermarks Initiative HolyGrail 2.0 is a pilot project to prove the viability of digital watermarking technologies for accurate sorting and consequently, higher-quality recycling and the business case at a massive scale. Digital watermarks are imperceptible codes, the size of a postage stamp, covering the surface of a consumer goods packaging, and encoding a wide range of attributes.

The aim is that once the packaging has entered into a waste sorting facility, the digital watermark can be detected and encoded by a standard high-resolution camera on the sorting line, which then – based on the transferred attributes (for example, food vs non-food) – can sort the packaging in corresponding streams. This would result in better and more accurate sorting streams, resulting in higher-quality recyclates benefiting the complete packaging value chain.


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