Life cycle assessment of leather treatment at various scales: comparison between chrome and vegetable processes

PurposeThis study assesses the environmental performance of all tannery process phases of an Italian artisan tannery, based on primary data, from hides to leather production, and discusses circular pattern options. The study focuses on the potential environmental impact of a traditional artisan company, identifying and evaluating chrome and vegetable tanning options, analysing resource efficiency, and suggesting circular scenarios, to discuss the potential benefits of shifting to a circular perspective.MethodsThe life cycle assessment is a standardised framework for evaluating the environmental impact of processes under human control. The study defined the functional unit and system boundary, collected primary and secondary data for the life cycle inventory, and performed life cycle impact assessment using the ReCiPe midpoint hierarchist method. The study identified hotspots within chrome and vegetable tanning options and interpreted the results aiming at providing recommendations for sustainable and circular production pathways. A sensitivity analysis was conducted to estimate the effect of alternative circular scenarios.Results and discussionThe tanning phase is the hotspot for chrome-tanned leather, with the most significant impacts in the Retanning process. For vegetable-tanned leather, the pickling phase is the hotspot with the liming process as the most significant contributor. Both tanning options exhibit significant local emissions, presenting substantial impact potential in water consumption potential during the pickling phase due to the amount of consumed water for the liming process. The vegetable option shows substantial impact reductions, ranging from 20% in ozone depletion potential to 100% in human carcinogenic toxicity potential. Leather production from the circular-vegetable perspective would prevent significant environmental impacts, such as carbon dioxide and 1,4-dichlorobenzene equivalents and saving a considerable amount of water.ConclusionsThis study provides reliable and realistic results using primary data, supporting the spread of the circular economy perspective. The vegetable option has substantially reduced impacts due to using natural tanning compounds. Implementing circular patterns achieves even more significant reductions in all impact categories. The shift from local to a national scale and from linear to circular patterns enables maintaining high-quality final products while fulfilling sustainable goals. To promote the circular economy, Italian policy should incentivise the implementation of circular patterns across various scales, extending it to consortium industrial districts and small facilities, support local territories to reduce operational costs of new sustainable installations, overcome risks and barriers of competitive investments, and promote the management of operational information systems to achieve both short-term goals and long-term strategies.