Industrial symbiosis: how can it help the transition to circular fashion?

The circular economy is a model of production and consumption that involves sharing, reuse, repair, reconditioning and recycling of existing materials and products, keeping them in circulation for as long as possible. This extends the life cycle of products and helps to minimise waste.

It is a development model that addresses global challenges such as climate change, biodiversity loss, waste and pollution and is based on 3 principles:

• Eliminating waste and pollution
• Extend the life of materials and products
• Regenerating natural resources 

The principles of the circular economy contrast with the traditional linear economic model based on the typical "take-make-use-dispose" scheme, which depends on the availability of large quantities of materials and energy easily available and at low prices.

The circular economic model is therefore a valid and effective tool to mitigate the environmental impacts associated with the textile and fashion sector, which is responsible for 10% of global carbon emissions.

One of the main tools to support the circular economy in the fashion sector (and not only) is the industrial symbiosis, which involves the creation of a network of companies operating in similar or different sectors, in order to promote the exchange of by-products and production waste, avoiding to dispose of them in landfills and using them as new resources to be reused in production processes.

Industrial symbiosis: what is it?

Industrial symbiosis means the transfer of resources between two or more different industries, meaning "resources" not only materials (such as by-products), but also energy and/or water resources, services, infrastructure, information and skills.

The industrial symbiosis, through the transfer of surplus or under-utilized waste resources from one industry to another, allows to achieve economic and environmental benefits deriving from the lack of waste disposal and avoided consumption of virgin raw materials. The industrial symbiosis allows therefore to obtain solutions of type "win-win", in which all the involved actors can take advantage from the reciprocal interactions.

One of the projects of industrial symbiosis carried out in Italy is represented by the “First Macrolotto of Prato”. The project involves textile and fashion companies and aims at the enhancement and reuse of water resources. 

The Macrolotto is equipped with an industrial aqueduct managed by G.I.D.A. s.p.a. and fed by a centralized wastewater recycling plant. In 2016, Confindustria Toscana Nord and Gida signed an agreement to structure an analytical campaign for the monitoring of the water quality of the industrial aqueduct.

In the northern part of the plant, through three sewage pipelines, comes the wastewater produced by the citizens and industries of Prato. The wastewater comes for 20% from civil users, while the remaining part comes from industrial users and is strongly characterized by the presence of detergents, textile oils (emulsifiable oils, used to lubricate machinery and fibers being processed), dyes (mainly organic), and suspended solid particles (especially hairs and small fragments of wool fiber residues of processing).

The recovery of the water to be recycled takes place mainly through filtration on sand/anthracite and activated carbon. 

The water, at the end of the purification process, can be partially returned to the surface water system, while a part is sent to the plant for further treatment by biofiltration for its industrial reuse.

The centralized wastewater recycling plant is able to produce over 5,000,000 cubic meters/year of recycled water, which is used for different purposes:

• In the production cycle of the textile companies operating in the 1st edition. Macrolotto
• As a centralized fire protection
• For all toilets in the largest business center in this area

Other initiatives of industrial symbiosis have involved the tanning district of S. Croce sull'Arno, which represents the largest leather production area in Italy, producing 35% of tanned leather and 98% of sole leather.

In the cluster, there are about 600 companies active in the tanning industry, for a total of about 6,000 employees (most of them with less than 12 employees). The main final destination of the finished leather produced in Santa Croce sull'Arno is the footwear industry.

The following "collective" initiatives have been activated within the cluster:

• Wastewater treatment plant of Aquarno S.p.A.: every year the plant receives about 3,600,000 m3 of industrial wastewater and about 1,000,000 m3 of urban wastewater
• Eco-foam plant (Aquarno): the main objective of the plant is to recover the sludge from the Aquarno wastewater treatment plant, which is conveyed through a specific pipeline. The treatment capacity is about 100-120,000 tons per year and the treated sludge is recovered as inert material
• Consorzio Recupero Cromo (Aquarno): a private company composed of 240 member companies from all over the district. These companies send liquid waste containing chromium to the consortium for metal extraction. The recovered chromium is then returned to the original companies, who reuse it directly in their tanning processes. The plant can produce over 21,000 kg of basic chromium sulfate per day.
• Consorzio S.G.S. Spa (Carniccio and Rasature recovery plant): a private company composed of 230 associated tanneries. The plant processes daily about 200 tons of animal by-products from leather processing, producing fertilizers
• Cuoiodepur wastewater treatment plant: this is a second wastewater treatment plant that receives about 1,700,000 m3 of industrial water emissions per year and recovers its sludge as fertilizer.

To evaluate the environmental benefits of the initiatives of industrial symbiosis in the tanning industry, a Life Cycle Assessment study was conducted "from cradle to gate"which evaluated the environmental impacts from animal husbandry to tanned leather production at the S.Croce sull'Arno cluster. The functional unit considered was 1m2 of tanned leather produced in the cluster of S. Croce sull'Arno. The objective of the study was to compare two different scenarios:

• Scenario 1: in which the initiatives of industrial symbiosis have been implemented (that is the current scenario)
• Scenario 2: a hypothetical scenario in which initiatives of industrial symbiosis are less adopted.

From the study, it is evident that the initiatives of industrial symbiosis have improved all the categories of environmental impact considered. The main environmental benefits were obtained in the impact category "climate change", with an improvement of 21.87% and an absolute reduction of about 4.3 kg of CO₂ equivalent per m2 of a finished skin. The second impact category in which the best results were found was terrestrial eutrophication, with an improvement of 18.51%.

These demonstrate the importance of initiatives of industrial symbiosis in pursuing the mitigation of environmental impacts associated with industrial activities of the fashion industry and beyond.

What are the benefits and weaknesses of the industrial symbiosis?

The industrial symbiosis can lead to the optimization of industrial processes, the improvement of logistics and the transfer of knowledge, thereby increasing the productivity of all available resources and generating economic, environmental and social benefits as:

• Reduce raw material, energy and waste disposal costs
• Development of new market opportunities
• Optimization of the use of resources
• Reduction of environmental pressure and pollutant emissions
• Disposal of waste in landfills 
• Promoting cultural change focused on the sharing economy

There are, however, some barriers that may limit the spread of initiatives of industrial symbiosis:

• Regulatory barriers: Government laws and regulations can be obstacles to the development of industrial symbiosis projects between companies (see conditions under which a residue can be considered a by-product instead of waste, which often causes confusion between producers) 
• Economic barriers: To reuse by-products from other companies, companies may face significant investment in new technologies and infrastructure
• Technological barriers: recovery and reuse of by-products can be problematic due to lack of appropriate technologies
• Information barriers: often companies are not aware of the by-products available on the market and potentially reusable
• Cultural barriers: Many companies see waste and by-products as a problem to be solved rather than a new resource. Poor knowledge of the potential benefits of exploiting by-products is one of the main barriers to the development of industrial symbiosis.

Case studies of textile and fashion companies that have based their business on industrial symbiosis

Several textile and fashion companies have based their business on the principles of industrial symbiosis, including:

• Orange Fiber: Italian company that produces fabrics from citrus by-products. Using the residues of the citrus industry, which is all that remains after the production of juices and that otherwise should be disposed of with economic and environmental costs, Orange Fiber produces high-quality fabrics for the fashion-luxury segment
• Vegea: Italian company that reuses and transforms biomass and agro-industry residues as new materials for fashion, furniture, packaging, automotive and transport. In particular, in collaboration with Italian wineries, they have developed a process for the enhancement of wine waste: the marc, composed of skins, stems and pips discarded during the production of wine
• Chiengora: the start-up Modus Intarsia has developed a new type of yarn obtained from the undercoat of dogs removed during grooming. This often neglected but abundant raw material is transformed into a high-quality yarn for applications in fashion and furniture.

Conclusion

The initiatives of industrial symbiosis represent a valid solution to facilitate the transition of the textile and fashion sector towards greater circularity. Through the enhancement of by-products, in fact, companies can avoid using virgin raw materials and, at the same time, sell their waste to companies interested in their reuse, reducing disposal costs.

In this way, industrial symbiosis projects can provide companies with various environmental, economic and social benefits.

However, there are several regulatory, social and technological constraints that hinder the development of industrial symbiosis initiatives between enterprises.

To overcome these barriers, it is essential that the companies that are part of the network work together, there is clarity in the rules concerning the management of by-products and a real interest of the sector in investing human and financial resources to support research and development activities. In this way, the development of industrial symbiosis projects can be encouraged.