Leather-based fertilizers from Personal Protective Equipment (PPE) reverse logistics: Technical efficiency and environmental safety

Agriculture and industry are seeking healthy food and enough goods to meet the global demand without causing environmental impacts, which motivates the search for sustainable and eco-efficient technologies. This study focuses on reverse logistics in the Personal Protective Equipment (PPE) industry.  Chrome-tanned leather shavings from the manufacture of PPE and post-use leather PPE were used to produce leather-based fertilizers (LBFs), which were evaluated for their agronomic efficiency and food safety. N-rich liquid LBFs were successfully produced through hydrolysis, either with or without previous chromium extraction. At the dose of maximum technical efficiency, LBFs are safe, with acceptable levels of Cr in the plant biomass and the soil compartments. However, LBF overdoses promote Cr accumulation in plants and soils, which demonstrates the need for a rigorous control over the fertilization management to ensure successful PPE reverse logistics.