Industrial symbiosis: from waste to resources

In the field of industrial ecology, industrial symbiosis refers to the interaction between different industrial plants to maximize the reuse of resources normally considered waste. These resources include material (waste and products), or intangible (energy, water, services and skills) resources.

Waste generated by one firm can be used by another firm to replace production inputs or transformed into new products for the end market. Industrial symbiosis is now considered one of the main strategies for the transition to the circular economy.

From an economic point of view, companies benefit by avoiding disposal costs. Plus they gain additional revenues from selling by-products and purchasing cheaper resources. Whereas, from an environmental point of view, resource consumption and land impact are reduced.

What is industrial ecology?

In 1992, physicist Robert Frosch introduced the concept of industrial ecology during his lecture “Towards and Industrial Ecology” at the United Kingdom Fellowship of Engineering. This is an interdisciplinary field of study focused on the design and optimization of industrial systems to minimize environmental impact.

Within industrial ecology, the world economy is viewed as a network of industrial processes that extract resources from the earth and transform them into goods that are then bought and sold to meet humanity’s needs. The purpose of industrial ecology is to quantify and study this network of continuous exchange through the analysis of industrial processes.

Industrial ecology, therefore, aims to create sustainable production systems that minimize the consumption of natural resources, waste generation and pollution. This creates a virtuous cycle in which one company’s waste becomes a resource for another, so that waste production and pressure on the environment are reduced.

History of industrial symbiosis

One of the first people to give a specific definition of industrial symbiosis was Marian Ruth Chertow, a professor at Yale University, who showed how achieving industrial symbiosis requires essential factors such as “collaboration between companies and synergy opportunities available in a geographically and economically homogeneous context.”

Industrial symbiosis is thus proposed as a tool for closing resource cycles so that resources are exchanged and a circular economy circuit can be generated.

The word symbiosis is derived from the Greek syn (with) and bios (life). The most common application of the word is in biology, where symbiosis refers to the association between two or more individuals from different plant or animal species, both of whom benefit from living together. Even better known is its extension into figurative language, where to be in symbiosis can be different people, artistic currents, or other different realities.

In 2003, a national industrial symbiosis program was implemented in the United Kingdom as an operational tool for sustainable industrial planning, called the National Industrial Symbiosis Program (NISP), which has since been replicated in 20 other nations.

Advantages and disadvantages of industrial symbiosis

Industrial symbiosis can lead to the optimization of industrial processes, improved logistics, and foster knowledge transfer, consequently increasing the productivity of all available resources and generating economic, environmental, and social benefits such as:

• Reduced costs of raw materials, energy and waste disposal
• Development of new market opportunities
• Optimization of resource use
• Reduction of pressure on the environment and pollutant emissions
• Elimination of waste disposal in landfills

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

Regulatory barriers: government laws and regulations can be barriers to the development of industrial symbiosis projects among companies (see the conditions under which a residue can be considered a by-product rather than a waste, which often cause confusion among producers)
Economic barriers: in order to reuse by-products from other companies, companies may face significant investments in new technology and infrastructure
Technological barriers: recovery and reuse of by-products can be problematic due to the absence of appropriate technologies
Information barriers: companies are often unaware of commercially available and potentially reusable by-products
Cultural barriers: many companies view waste and byproducts as a problem to be solved rather than a new resource. Lack of knowledge of the potential benefits of by-product reuse is a major barrier to the development of industrial symbiosis.

Examples of industrial symbiosis

One of the most emblematic and well-known cases of industrial symbiosis is that of the Kalundborg eco-park in Denmark. In this place, a process of industrial symbiosis began spontaneously since the 1960s as a result of the need to find an alternative solution for water supply. Six companies-a power plant, an oil refinery, a biotechnology company, a building products company, a waste management company, and the local government-began to cooperate, deriving common benefits through an open management style in an atmosphere of mutual trust.

Initially, the symbiosis was aimed only at the supply of water resources; as time passed, and connections were fortified, the first exchanges of materials and energy resources began. In 1996, the Kalundborg Symbiosis Center, a so-called “matchmaker,” was established to cope with the problems of managing, coordinating and expanding the symbiosis network with new participants.

The second successful case is in France, in Dunkirk. This is a highly industrialized area with metallurgical, chemical and petrochemical, energy, food, and logistics companies that have generated high levels of pollution for years. In this context, the Écopal with the aim of promoting circular economy projects with a view to reducing the environmental impact of production processes.

Industrial symbiosis in Italy

One of the industrial symbiosis projects implemented in Italy is represented by Primo Macrolotto in Prato. The project involves companies in the textile and fashion sector and aims at the valorization and reuse of water resources.

The Macrolotto has 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 entered into an agreement to structure an analytical campaign to monitor the water quality of the industrial aqueduct.

In the northern part of the plant, wastewater produced by citizens and industries in Prato arrives through three sewer pipes. Twenty percent of the wastewater comes from civil users, while the remainder comes from industrial users and is strongly characterized by the presence of detergents, textile oleants (emulsifiable oils, used to lubricate machinery and fibers being processed), dyes (mainly organic in nature), and suspended solid particles (mainly pelurie and small fragments of wool fiber residues from processing).

The recovery of the water to be recycled is basically through filtration on sand/anthracite and on activated carbon. The water, which has thus reached the end of the purification process can be partly returned to the surface water system, while a part is sent to the plant for further treatment by biofiltration for its industrial reuse.


In order to develop an industrial symbiosis, it is in any case necessary to manage a close collaboration between government agencies, stakeholders and territorial communities.

It becomes essential to obtain, and first and foremost work on, a common consensus and participatory planning. In addition, establishing a good waste management system can take time and significant investment.

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Emma Salioni

WIth a degree in Digital content management for media, enterprises and cultural heritage, Emma Salioni has always had a strong interest in sustainability and circularity. After a period of time spent workin in The Netherlands, she started working with Tondo managing social media and communication, as well as supporting the organization of hackathons and events.