Modelling the leather industry waste from the circular economy perspective. A depth-review

The tanning industry is a significant economic sector in Italy, but also a source of high environmental impacts. Many studies underlined the issues of each phase of the leather production cycle, looking for more ecofriendly solutions. This research was encouraged by the Sustainable Development Goals set by the 2030 Agenda, in particular goals 12 and 13 which respectively promote responsible consumption and production and the fight against climate change. In support of these goals, the application of circular economy (CE) practices allows both a reduction of the environmental impact and economic savings. The tanning industry indeed produces a huge amount of liquid and solid waste, and the CE model allows both the prevention and the recovery of such waste. This paper provides a review of the potential applications of the CE to the tanning sector through the design of eco-sustainable products and the reuse of waste as secondary raw materials within the same or other production processes. The use of biological, chemical, and thermal techniques allows for a high degree of reducing waste production and recycling of secondary materials with a significant decrease of the environmental pollution.