The benefits of a circular economy in the tanning processA study conducted by the High School of Sant’Anna di Pisa in the district of Santa Croce highlights the advantages for the environment in the abandoning traditional linear economy.
The circular economy is a very popular concept in various fields, from politics to the economy, from international policies to academia. However, if we consider circular economy policies as policies aimed at achieving a real environmental improvement due to the shift from a linear to a circular approach, it is good idea to clarify how to measure this improvement. Too often, initiatives aimed at closing the cycle, i.e. activation of recovery and recycling routes for by-products and waste, are identified as “sustainable” regardless, for example, of whether they require the application of a particularly energy-intensive technology or an increase in the impacts deriving from the logistics of these materials, or environmental costs that could more than frustrate the benefits coming from the initiative’s circularity.
A method that effectively compares the environmental relevance of two processes or products exists and it is called LCA or Life Cycle Assessment, which is governed by a specific ISO standard. This tool has been applied by a research group of the Management Institute of the High School of Sant’Anna di Pisa in an innovative way, as it does not measure the environmental benefit of the application of a circular economy to a product or process, but to an entire industrial district: the tanning district of Santa Croce sull’Arno. The research – presented during the AICC 2018 conference by Tiberio Daddi, researcher of the Sant’Anna School, and published in the prestigious American Journal of Cleaner Production – aimed to measure, through the application of the LCA, the environmental benefits of the circular initiatives of the tanning district carried out by the consortiums located there: the Consorzio Recupero Cromo (Chromium Recovery Consortium), which collects wastewater from chromium, and obtains chromium salts for reuse in the district, the Aquarno Consortium, which recovers sewage sludge for reuse in the construction sector, the SGS Consortium, which recovers protein residues such as shavings and fleshings and uses them as soil improvers, the Cuoiodepur Consortium, which recovers sewage sludge in agriculture. The researchers of the Sant’Anna School collected data from all the recovery consortiums and from a group of 22 tanneries representing the district with the help of local trade associations. The aim of the research was to compare the environmental impact of 1 m2 of leather produced in the Santa Croce district with 1 m2 of leather produced within consortiums that did not implement circular economy initiatives.
The results have been particularly interesting. The study highlighted considerable environmental benefits deriving from consortiums of the Santa Croce tanning district. For example, 1 m2 of leather produced in Santa Croce allows reducing the impact on climate change (carbon footprint) by about 22%, a benefit linked to terrestrial and aquatic eutrophication impacts of respectively 19% and 12%.