Reducing footwear waste going to landfill

Highlighting the steps SATRA is taking to repurpose the waste it produces.

by Harriet Mason

The number of shoes produced internationally is increasing every year. As a result, there is an enormous amount of waste produced by the footwear industry currently being disposed of in landfill sites around the world. The issue of footwear end-of-life waste is currently being tackled in a number of ways: i) reusing, for example by donating used items to a local charity or as foreign aid; ii) repairing: iii) recycling parts such as the laces; and iv) considering the use of recyclable or biodegradable materials in production. Leather, polyvinyl chloride (PVC), polyurethane (PU) and vulcanised rubber may all contain chemicals that potentially pose a problem to landfill sites. The three main areas of the footwear industry that produce waste are supply, manufacture and post-consumer. Lean manufacturing initiatives and the use of systems such as SATRASumm and SATRA VisionStitch are well established and have led to a reduction in supply and manufacturing waste. Post-consumer waste has been an issue for some time but with the rapid rise of consumerism and its impact on the environment a sense of urgency to find practical solutions is growing.

With the development of technologies and the increasing use of ‘performance’ materials and components in footwear, typically only specific parts can be recycled. This is quite an issue, as a shoe may contain many different materials and adhesives which cannot be reused or recycled. The footwear must, therefore, be deconstructed.

Supporting the environment

As well as trying to identify technologies and methods to help brands and manufacturers produce more sustainable products, SATRA continually seeks ways to improve its own operations and reduce negative impact on the environment. One example is the way we now dispose of waste product and materials after testing. Around 400kg of waste footwear items are collected from SATRA each month by a local recycling company. It is destroyed securely, ground up in a ‘can baler’ with an integrated magnetic separator, and then turned into a dry pellet form to be used as ‘refuse-derived fuel’ (RDF). A certificate of destruction is provided at the end for SATRA’s records.

Changing shoes into fuel

RDF technology produces energy from waste that is unsuitable for traditional recycling and that would be sent to landfill if not shredded and repurposed. In the RDF manufacturing process, non-combustible materials such as glass and metals are removed, after which an ‘air knife’ is used to separate lightweight materials from heavy items. The light materials – including some plastics – have higher calorific value and are used to produce the final fuel, while currently the heavy materials normally continue to a landfill (although taking up less volume than otherwise would be the case).

The items destined to become RDF are shredded into a uniform homogeneous material, which can be used as a plain mixture or compressed into pellets, ‘bricks’ or ‘logs’. This can become a substitute for fossil fuels in the production of cement or lime or as a reduction agent in steel furnaces. RDF can also be used in a variety of ways to produce electricity, such as alongside traditional sources of fuel in coal power plants. Utilised in this way, RDF technology provides a way to recover a significant amount of waste while at the same time contributing to the generation of energy.

Since the 1950s, when tyres were used as RDF in the cement industry, the technology has continued to improve. During the eighties, the German Cement Works Association began to document the use of alternative fuels in the national cement industry. While in 1987 less than 5 per cent of fossil fuels were replaced by RDF, its use had increased by 2015 to almost 62 per cent.

Recycling doesn’t just stop at footwear and we look to recycle as much as possible from all the product sectors in which SATRA actively tests. Certain mattresses and pillows which previously would have gone to landfill are now shredded and made into packaging material. Elsewhere, we are investigating what personal protective equipment (PPE) might be converted into RDF now and in the future.

Repurposing components

There are many parts of footwear and clothing that can be reused for other purposes. The Phoenix Resource Centre is an environmental charity working in 61 countries that examines industrial waste and tries to reuse it as foreign aid, mostly in Djibouti and Ghana. All reused products are traceable and cannot be resold. Products that aren’t sent out as foreign aid, because they have sensitive branding or are damaged, are stripped of all parts that can be repurposed, including laces, eyelets, zips, buttons and stuffing and passed to schools and similar institutions as arts and crafts supplies. The charity works purely with volunteer workers, and has forged partnerships with a number of other organisations. Its resource centre is also used as a respite to help people with carers become more employable and give them opportunities in life.

There are many ways in which the footwear industry can become more sustainable. If you are interested in this topic, it may be worthwhile reviewing previous SATRA Bulletin articles, including ‘Recycling and recyclability’ and ‘Sustainability in footwear production’. Alternatively, please feel free to contact us at any time with any specific requirements or if you wish to explore a project.

Publishing Data

This article was originally published on page 30 of the March 2020 issue of SATRA Bulletin.

Other articles from this issue »

---