Global footwear production figures indicate that 23 billion pairs of shoes are being made and sold every year. Potentially, every single one of these will someday end up as waste material needing to be managed.

The AIR Soex project is a spin-off from collaboration between the innovation consulting agency AIR (Agence Innovation Responsable) and the German company SOEX, which is engaged in the collection, sorting, recycling and reclamation of used textiles and footwear, in collaboration with I:Collect, an international specialist that collects, reuses and recycles textiles and footwear.

The project, financed by Eco TLC, the eco-organisation that manages the levy on life-expired shoes, textiles and household linen, aims to demonstrate the technical feasibility of separating out the various materials in used footwear. In so doing, each component can be reclaimed, avoiding the need to incinerate used footwear or send it to landfill. In France, with the exception of a small percentage of shoes that are reused, 415 million pairs are discarded annually, and these are either incinerated or go to landfill.

A promising prototype

The technical feasibility of this initiative has already been proved via the development of a pilot plant (a prototype that can process 100kg of shoes a day) and, following a great many trials and modifications, this operation has been followed by the construction of an industrial-scale facility. This plant, representing a €1-million investment, opened in June 2018 at Bitterfeld-Wolfen in Germany, and provides automated processing of 1t of footwear every day (around 2,000 pairs).

The operations involved are purely mechanical and comprise the following stages: grinding; extraction of ferrous metals; delamination, enabling non-ferrous metals to be recovered, and also textiles in the form of wadding; separation of foam, textile, leather and rubber using a hydrocyclone; and grinding into powder. Once the materials have been sorted, the project’s economic viability depends on the return obtained on the various reclaimed products.

A number of markets for reclaimed materials have been identified within the framework of the project:

  • Ferrous and non-ferrous metals: numerous markets (though the quantities reclaimed are relatively small).
  • Rubber: manufacture of safety surfaces for playgrounds or inclusion in shoe soles.
  • Textiles: thinking is under way on how these can be included in non-wovens.
  • Leather: no real market identified.

The Thermicuir project, which is being led by CTC and co-financed by Eco TLC, aims to exploit the thermal energy content of this residue, using gasification technology. Ground leather reclamation technology offers the additional benefit that it can also use production off-cuts, like tannery shavings, off-cuts from the manufacture of fine leather goods and shoes, and textiles. The energy generated could be used directly in the production process, raising the prospect of a circular economy.

This project, headed up by Régis Léty, will feature in a forthcoming article in the ‘CTC Entreprise’ newsletter, but at this stage it can already be said that the initial results look encouraging.

SOEX footwear recycling plant – the facts

  • Duration of development: five years (2013 to 2018)
  • Employees: two per shift
  • Total investments: around €1 million
  • Officially commissioned: June 2018
  • Throughput per shift: approximately 1t or 2,000 pairs of shoes (one pair of shoes = 500g)
  • Waste reduction per shoe: up to 70%
  • Reduction of daily shoe waste: up to 45% (15% per shoe recycling shift)
  • Daily tonnage of shoes at the Wolfen sorting plant in 2017: 27t or 54,000 pairs
  • Secondary raw materials derived: rubber, leather, foam materials, metals
  • Current waste products: textile materials

Source: CTC

Project history

  • 2007: The Centre of Sustainable Manufacturing & Recycling Technologies (SMART) at the University of Loughborough launches a research project on footwear recycling.
  • 2009: SOEX is invited by head of the SMART Centre Professor Shahin Rahimifard to participate in a footwear recycling research project.
  • 2011: French agency Agence Innovation Responsable (AIR) organises a shoe recycling workshop with a variety of international attendees. SOEX is among the participants and proposes that a global overview of functional footwear recycling technologies be compiled.
  • 2012: AIR, French company EcoTLC and the French Environment & Energy Management Agency (ADEME) launch a worldwide search for the most promising footwear recycling technologies. The company In-Cycle is founded in the UK with the aim of developing technologies for shoe recycling. SOEX decides to drive the topic of shoe recycling and to look for corresponding solutions.
  • 2013: SOEX brings AIR and In-Cycle together. The two embark on a joint project with the aim of developing new footwear recycling technology. SOEX and EcoTLC support the project, providing expertise and financial backing.
  • 2014: The first prototype of a machine able to mechanically separate shoes is set up and tested. Capacity is 100kg of shoes a day.
  • 2016: The first complete pilot plant for footwear recycling is commissioned by SOEX. Together with partners, the secondary raw materials extracted are tested for use in various areas.
  • 2017: Application testing continues and the sale of secondary raw materials (rubber, leather and foam) derived from the footwear recycling process begins.
  • 2018: Launch of the world’s first plant for the industrial-scale recycling of all footwear types.

Source: CTC