Tannery Waste

Industrial shredders are used in many industries, but their contribution is not always adequately valued. A strategic sector for our country’s economy is Made in Italy. This article illustrates a customized shredding solution that directly involves this type of market.

The customized installation described below consists of a 50 HP twin-shaft shredder working in concert with a 125 HP three-shaft shredder through a system of conveyor belts. The application is very specific, but allows us to address, albeit tangentially, a very important issue: the ecological impact of Italian manufacturing.

In Italy, one of the industries of excellence is tanning. Leather is a widely used material in Fashion: bags, footwear, and small leather goods are among the healthiest sectors of the entire manufacturing industry.

The sector, as a whole, generated revenue of 68.5 billion euros in 2023, an increase of 5.8% compared to 2022. Exports rose by 6.3% and Italy is the second largest exporter of leather goods in the world, after China.

In our country there are over 1,200 companies involved in the leather industry. They are concentrated, for the most part, in Veneto, Campania and, above all, Tuscany, where the historic Leather District of Santa Croce sull’Arno is located. The sector knows no crisis: Tuscan leather has seen a doubling of exports in the period 2007-2023, rising from 1.8 to 4.3 billion euros.

Such an important market represents an asset for the entire nation. However, in addition to the merits of an industry unique in the world, we must also consider the responsibilities that follow such a primacy. If, in fact, we boast of production, we must not forget the proper disposal of tannery waste. From a circular economy perspective, understanding how to reduce the environmental impact of an industry is the first step toward optimizing processing procedures, reusing materials, and reducing waste.

Leather and hide are naturally biodegradable materials. The tanning process, however, makes them more resistant and difficult to dispose of. But that’s not all: during tanning, toxic chemical components and a large quantity of water are used.

Since leather and hide require processing with a high carbon footprint, proper disposal, but above all, the reuse of these materials, are fundamental from a sustainability perspective. Shredding, therefore, is an essential step to reduce waste, recovering not only the finished product, but also all the semi-finished material that is discarded during production.

The processing procedure that takes raw leather to the finished product produces various by-products: wastewater, solid waste, fats, chemical products. It is essential to identify processing procedures with minimum resource consumption and emissions. The leather industry also drives a market that involves not only leather goods, but also sectors such as furniture and automotive.

In specialized plants for the tanning industry, shredders play an important role. One example is the management of trimming tannery waste, i.e., the non-conforming parts of leather that are removed during the initial production phases, processed by an Italian company that is a world leader in transforming these processing residues into biostimulants for agriculture.

This is precisely the purpose of the two twin shredding lines, both composed of two shredders operating 24/7: one twin-shaft and one three-shaft connected by multiple conveyor belts, remotely controlled in a completely automatic manner. The control panels with Siemens PLCs, equipped with connections for remote management via both #Profinet and #Profibus, are equipped with remote assistance. The systems comply with the most recent Industry 4.0 requirements.

The first material pass is performed by a 37 kW (50 HP) medium-power twin-shaft shredder with 50 mm thick single-hook blades. The second pass by a 93 kW (125 HP) three-shaft shredder, with 50 mm thick 5-1 hook blades and discharge grids with hexagonal holes. The two machines are connected by a 10 m conveyor belt.
At the outlet of the three-shaft shredder, the material is collected by a 2 m horizontal weighing belt that conveys it to a second 4.5 m conveyor belt equipped with an Overbelt. After the discharge of ferrous material from the line, a third 5 m belt carries the material to a tank for hydrolysis.

Our sales team is at your disposal to provide you with further information and present our extensive range of industrial shredders and support you with any waste shredding issues.