The latest trials, conducted at the Hündgen Entsorgung material recovery facility (MRF) in Swisttal, Germany, assessed the efficiency of digital watermarking applied to rigid household packaging collected in Germany and Denmark. The facility, which processes 100,000 tonnes of waste annually from 3 million households, was equipped with detection prototypes and add-on modules co-developed by technology provider Digimarc and machine supplier Pellenc ST. These modules combined near-infrared (NIR) and digital watermarks (DW) technology for enhanced sorting accuracy.
The trials ran from 19 August to 19 December 2024, with a view to assessing sorting performance across multiple packaging material types and formats. The sorted material volumes were remarkable, with detection rates reaching an average of nearly 56,000 detections per day, totalling 5.66 million detections of 5,949 unique SKUs over the 100-day period. Detection efficiency ranged from 87.9% to 93.8%, consistently exceeding 90% through rigorous cloud-based analysis.
Key outcomes
The trials focussed on post-consumer rigid packaging waste across four different types and formats: PET non-food bottles, rigid PP, rigid PE (including tubes), and PET trays. Participating companies Aldi, Arla foods, Netto Marken-Discount, Haleon, Hochland, Mondelēz International, Orkla, Procter & Gamble had previously enhanced their SKUs with digital watermarks, and placed them on the German and Danish market for consumer use, disposal and collection in designated areas.
The streams were additionally bulked up with further quantities of digitally watermarked drinking cups by Coca-Cola and McDonald's. In a similar vein, sorting trials were also carried out on tobacco canisters by Imperial Brands.
Sorting efficiency and purity were measured across the different material fractions, achieving the following sorting efficiency and purity results:
