Evaluating the Circular Footprint Formula (CFF) in the environmental assessment of mono-material carpets recycling: a case study approach

The purpose of this study is to apply and evaluate the Circular Footprint Formula (CFF), as part of the European Commission’s Product Environmental Footprint (PEF) framework, through an assessment of the environmental performance of thermomechanically recycled mono-material polyester carpets. Unlike multi-material carpets that are often incinerated at the end of their life, mono-material designs facilitate fiber-to-fiber recycling - a key priority for the European Union in reducing the large environmental burdens of the textile industry. The environmental assessment is structured around the CFF as recycling allocation method. In addition, a comparison is made with the 100:0 approach as a benchmark, also known as the cut-off or recycled content method, as recommended in the Environmental Product Declaration (EPD). Different potential values for two main parameters within the CFF were considered: factor A, reflecting the market dynamics of supply and demand for recycled materials, and factor B, distributing the burdens and credits associated with energy recovery. Both allocation methods were applied to the carpet case study, which considered three possible scenarios: recycling of the monomaterial carpet (MMC), incineration of the conventional multi-material carpet, and incineration of the MMC. The impact assessment follows the indicators defined by PEF framework. The findings indicate that recycling of MMCs generally results in lower environmental impacts than direct incineration across most impact categories, thereby aligning with the principles of a circular economy. Importantly, incinerating MMCs without prior recycling can lead to more severe environmental burdens than the incineration of conventional carpets, as demonstrated through a comparative product system-level analysis. The results also suggest that factor A has a significantly greater influence on environmental outcomes at individual product level than factor B, with changes in A, for example, leading to impact differences of up to 30% for Climate Change. Additionally, yarn thickness (titer) plays an important role, as a shift from very fine to coarse yarns altered the relative environmental performance of the product systems. Methodological enhancements are recommended to improve the accuracy of environmental impact assessments for textile recycling scenarios when using the CFF within the PEF framework. The high sensitivity to factor A emphasizes the need for a scientifically robust selection process. Moreover, the substantial influence of yarn thickness underscores the importance of developing more detailed Environmental Footprint (EF) datasets to achieve more consistent and reliable sustainability evaluations in the textile sector.