What is Industrial Symbiosis?
Industrial Symbiosis — commonly shortened to IS — is a collaborative partnership between companies designed to maximise the value of the resources. It works through the exchange of materials, energy, services and expertise. In this model, what one company views as production waste becomes another’s resource. As a result, a virtuous cycle forms in which nothing is discarded and every resource finds a new purpose.
This is not an abstract theory. It is an operational model that allows companies to reduce disposal costs, open up new revenue streams and build solid industrial partnerships for the long term. Moreover, it connects industries that, traditionally, would have no reason to engage with one another. The main goal is to maximise the value of waste resources through the exchange of materials, energy, services and expertise.
Just as natural biological ecosystems sustain themselves through a continuous exchange of materials and resources, industrial systems can do the same through industrial symbiosis. What constitutes waste for one company may contribute to another’s production process; the two companies sign a commercial agreement, and what previously was a disposal cost becomes a market value.
The Difference Between Industrial Symbiosis, Circular Economy and Sustainability
The concept of Industrial Symbiosis is often confused for Circular Economy and Sustainability. Although frequently used as synonyms, they correspond to three distinct levels. Sustainability indicates the overarching strategy. The circular economy identifies the recycling and reuse production model, an alternative to the linear model. Industrial Symbiosis, however, puts it into practice by transforming the production process into a collaborative ecosystem.
In other words, whilst the circular economy defines the model, Industrial Symbiosis sets it in motion with real players, through measurable business agreements and concrete benefits for all parties involved.
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DISCOVER MARKETPLACEThe Origins of Industrial Symbiosis
Industrial Symbiosis is based on a simple question: what if industrial waste were not a problem to be disposed of, but a resource to be transferred?
The theoretical approach began in 1989 with Robert Underwood Ayres, who introduced the concept of Industrial Metabolism. His idea was that the production system functions like a biological organism: it receives raw materials, transforms them, and produces waste. In nature, what one organism discards becomes a resource for another. In industry, however, it is simply eliminated. Through the metaphor of the biosphere and technosphere, Ayres demonstrates that the industrial system can learn from nature. Studying where waste is generated, therefore, is the first step towards reducing or repurposing it.
In 1992, Robert Alan Frosch went one step further by introducing Industrial Ecology. This approach comibines methods used to study interactions between organisms with the logic of the production system between factories, cities, agriculture and trade. Frosch criticises the linear ‘Take, Make, Dispose’ model and proposed looking at industry as a network of relationships, in which the waste from one process becomes the resource for another.
Industrial Metabolism and Industrial Ecology complement each other: the former maps and measures material flows, whilst the latter reorganises them into a circular system. Together, they form the theoretical basis of Industrial Symbiosis.
It was Professor Marian Ruth Chertow who, in 2000, put this concept into practice, introducing the term ‘Industrial Symbiosis’ for the first time. Borrowing the concept of symbiosis from biology — the relationship in which two different organisms coexist by supporting one another — she applied it to industries. Companies with nothing in common, she argued, can exchange waste, by-products, water and energy. This creates a collective benefit that none could have achieved on its own.
More recently, the technical manual published in 2024 by ENEA and ISPRA provides an updated and more thorough definition:
“Industrial Symbiosis is a form of interactive synergy between actors within a geographical and economic area that aims to efficiently manage material and immaterial resources; through relationships, information and technological innovations, it allows for organisational, economic, environmental and social benefits to be achieved at both the local and systemic levels”.
Terms and Vocabulary of Industrial Symbiosis: understanding the words to understand the system
In the Industrial Symbiosis setting, correctly classifying a material determines how it is managed, what regulatory obligations it has, and what economic opportunities it generates.
The product is the intended outcome of a manufacturing process: the very reason that production activity exists. Anything produced by the process that is not the main objective falls into one of the following categories.
Waste, according to European Directive 2008/98/EC, is “any substance or object which the holder discards or intends or is required to discard”. For the company, it is a cost: it must be managed by certified operators and sent for treatments as required by law. Nevertheless, many materials classified as waste could be managed differently if correctly classified from the beginning.
A by-product is a material that originates as a side effect of a production process and can be reused directly, without additional treatment, in another process. A material can only be considered a by-product if:
- Further use of the substance or object is certain;
- The substance or object can be used directly without any further processing other than normal industrial practice;
- The substance or object is produced as an integral part of a production process;
- Further use is lawful, environmental and health protection requirements for the specific use and will not lead to overall adverse environmental or human health impacts.
If even one requirement is not met, the material is reclassified as waste. This distinction has significant economic implications: a by-product is an asset that can be sold on the market, not a cost item. It is on this principle that exchanges between companies in Industrial Symbiosis are based.
Secondary raw materials (SRMs) share with by-products the fact that they originate from processing residues. They differ, however, in that they have undergone processing, the so-called ‘End of Waste’, which restores characteristics comparable to those of virgin raw materials, making them a resource for new production cycles and reducing dependence on extractive resources.
| Waste | By-product | Secondary Raw Material | |
|---|---|---|---|
| What it is | A material that the company gets rid of or is required to get rid of | A production residue that can be reused straight away | Recycled waste that returns to being a resource |
| Origin | Unused waste | It is created as part of a production process | It is made from recycled waste |
| Economic Value | It is usually a cost that needs to be managed | It may be of value to other companies | It becomes a usable material on the market again |
| Treatment | Management and disposal/recovery | Standard industry practice | It must undergo a recycling process |
| Environmental impact | It must be managed to avoid negative impacts | It must not present any risks to the environment or human health | It must meet environmental and safety standards |
The difference between symbiotic networks and Eco-Industrial Parks
All these materials are used within two types of systems where industrial symbiosis is implemented on a systemic scale: symbiotic networks and eco-industrial parks.
A simbiotic network is a group of companies, not necessarily geographically close, that establish relationships for the exchange of materials and by-products. An eco-industrial park, on the other hand, is an industrial area designed from the start with the explicit aim of maximising exchanges between the companies based there. It is, therefore, a more structured and planned form of symbiotic network.
Industrial Symbiosis is not a bilateral agreement between two companies. Rather, it is a system of relationships that grows and consolidates over time. The benefit is not limited to a single transaction; as more companies build this type of relationship, a network forms: a network of mutual exchanges in which each participant is simultaneously a supplier and a customer, a giver and a receiver.
For companies looking to join this type of network, Sfridoo offers a practical entry point: find out how the marketplace works and how it facilitates the exchange of waste and byproducts between businesses.
Targets and Benefits of Industrial Symbiosis
The main goal of Industrial Symbiosis is to maximise the value of every resource used in the production process, transforming waste through collaboration between businesses. The paradigm shift is clear: moving away from the linear ‘Take, Make, Dispose’ model towards a Cradle to Cradle approach, in which materials are never discarded but continuously reintroduced into new production cycles.
At the core of every symbiotic relationship lies the win-win approach: those who provide waste reduce disposal costs, those who receive it cut supply costs, and the environment benefits from reduced waste and emissions.
In practice, Industrial Symbiosis promotes the efficient use of resources and energy, the exchange of materials, skills and knowledge between companies, and the gradual elimination of the concept of waste through ‘designing out waste’.
Economic Benefits
From an economic perspective, companies involved in symbiotic networks reduce sourcing costs, cut disposal costs and optimise management, transport and production. Over time, these networks tend to expand, bringing in new members and creating market opportunities and long-term partnerships.
Environmental Benefits
The environmental impact of Industrial Symbiosis is wide-ranging and affects the entire life cycle of resources. The recovery of waste reduces the amount of landfill waste, lowers CO₂ emissions and decreases the extraction of virgin raw materials, thereby easing the pressure on natural resources. It results in a production system with a structurally lower environmental footprint, capable of actively responding to the challenges of the ecological transition.
Social Benefits
Symbiotic networks generate new jobs and create new types of specialists: from managing material flows and classifying by-products to coordinating business networks. Furthermore, this process contributes to the development of skills and the growth of the local business community.
Industrial Symbiosis Models
In practice, how is the collaboration between companies set up? Depending on the geographical context, the number of companies involved and the desired outcomes, this collaboration can take various shapes. Scientific literature has identified two main models: the Continuous Model and the Batch Model.
The Continuous Model
The Continuous Model is the most structured and stable form of industrial symbiosis. It is implemented within Industrial Symbiosis Districts and Eco-Industrial Parks, where collaborations between companies become an integral part of the productive structure. Businesses share materials, energy, water and services through established, long-term relationships.
This model often stems from a top-down approach, with a public authority planning the industrial area according to the principles of symbiosis. In Italy, one example is the Ecologically Equipped Industrial Areas (AEA).
The Batch Model
The Batch Model adopts a different and complementary approach. Symbiosis develops through Industrial Symbiosis Networks: groups of companies, often spread across large geographical areas, without restrictions on geographical proximity.
Unlike the Continuous Model, it follows a predominantly bottom-up approach: it results from specific agreements between companies that identify concrete opportunities for symbiotic exchange. Its key strength, therefor, is its ability to adapt rapidly to market changes.
It is the Batch Model that provides the basis for digital platforms — marketplaces, SaaS solutions and shared ERP systems — tools that enable companies to share waste, resources and expertise, facilitating the matching of supply and demand even across physical distances.
Difference between the Continuous Model and the Batch Model
The Continuous Model works where there is a designated industrial area, with co-located businesses and a clear governance structure. The Batch Model, by contrast, is better suited to spread-out situations, where flexibility and speed of execution are key priorities. In both cases, the underlying principle is the same: moving away from a purely competitive approach in favour of collaboration that benefits everyone involved. A detailed overview of the two models is available in the article on the differences between the Continuous Model and the Batch Model.
The Industrial Symbiosis Law
At EU level, industrial symbiosis is recognised as a strategic driver for the transition to circular production models. Over the past fifteen years, the European Union has developed an increasingly extensive regulatory framework around this concept.
European legislation on industrial symbiosis
The European legislative process began between 2011 and 2015, when three communications from the Commission that placed industrial symbiosis among the Member States’ priorities, estimating potential savings of up to €1.4 billion per year. These reports were incorporated into the 2018 Circular Economy Package, which urged Member States to facilitate the recognition of by-products by prioritising replicable industrial symbiosis practices.
With the European Green Deal and the second Circular Economy Action Plan (CEAP 2020), the Commission has envisioned an industry-led certification system to implement symbiosis on a continental scale. The next milestone is the Circular Economy Act, expected in the second half of 2026: a binding measure to create a unified market for secondary raw materials and accelerate the rate of circular use of materials.
The Italian legislation
Italy has developed specific regulatory frameworks starting with the Bassanini Decree (L.D. 112/1998), which introduced Ecologically Equipped Production Areas (APEA): industrial zones designed to facilitate the sharing of resources between companies. The Environmental Code (L.D. 152/2006) then defined the concepts of by-product and End of Waste, which are fundamental for determining when a residue can be traded without being classified as waste. In 2016, moreover, Ministerial Decree 264 further clarified the criteria for classifying residues as by-products.
The most structural measure is the National Strategy for the Circular Economy (M.D. 259/2022), which identifies industrial symbiosis as one of the nine priority areas for action, with measurable targets up to 2035. The results for Italy confirm the success of this approach: a circular reuse rate of 21.6% in 2024, almost double the European average.
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REQUEST SHEETS NOWIndustrial Symbiosis around the world
Beyond Europe, China has adopted the most comprehensive regulatory framework with the Circular Economy Promotion Law (2009), which regulates industrial symbiosis at three levels — enterprise, eco-industrial park and regional system — and provides tax incentives for circular economy activities. The 14th Five-Year Plan of 2021 subsequently updated the targets in the context of achieving carbon neutrality by 2060.
South Korea, through the Framework Act on Resource Circulation (2016), has integrated waste management, recycling and industrial symbiosis into a comprehensive regulatory system, with the Ulsan eco-industrial park serving as a benchmark.
Brazil introduced the circular economy into federal legislation for the first time with Decree 12.082/2024, followed by Planec (2025–2034) with 71 concrete actions across five pillars, including the regulatory framework for secondary raw materials and financial instruments for circularity.
In the United States, there is no federal legislation dedicated to industrial symbiosis. Initiatives are developing at a local level. Although, a significant turning point has come from Oregon, which approved House Bill 4086 in the 2026 legislative session, the first state legislative measure specifically dedicated to industrial symbiosis in the United States.
The international regulatory outlook confirms a clear trend: industrial symbiosis is gaining ground well beyond Europe’s borders, and national legislation is gradually adapting, moving from isolated initiatives towards structured approaches.
Tools and Methods for Calculating Industrial Symbiosis
Launching an Industrial Symbiosis process requires analytical tools and shared metrics to assess material and energy flows, quantify benefits and support business decisions. Several methodological tools are available to companies and symbiosis facilitator.
LCA (Life Cycle Assessment) evaluates the environmental impact of a product or process throughout its entire life cycle, in accordance with ISO 14040 and 14044 standards. MFA (Material Flow Analysis), by contrast, systematically maps the inputs and outputs of an industrial district to identify opportunities for exchange. MIPS (Material Input Per Unit of Service) measures how many natural resources are mobilised for each service, whilst IOA (Input-Output Analysis) analyses the economic interrelationships between production sectors.
In addition, CBA (Cost-Benefit Analysis) compares the financial costs and benefits of a symbiotic project, ERA (Environmental Risk Assessment) evaluates the environmental risks associated with material exchanges, CERA (Cumulative Energy Requirement Analysis) calculates the total energy requirement, and WA (Water Assessment) analyses the impact on water resources.
Industrial Symbiosis performance indicators
Three categories of indicators are used to measure the performance of a symbiotic network. Environmental indicators quantify reductions in greenhouse gas emissions, waste sent to landfill, pollution and the consumption of natural resources. Economic indicators, on the other hand, assess reductions in production costs, increases in productivity, market competitiveness and the economic value of waste. Social indicators measure the impact on local communities in terms of employment, stakeholder engagement, quality of life, worker safety and corporate social responsibility.
The combined use of analytical tools and indicators allows companies to transform Industrial Symbiosis into a measurable management practice. As demonstrated by the case studies documented by Sfridoo, the systematic measurement of benefits is a precondition for upscaling Industrial Symbiosis models and generating a concrete impact at regional and national levels.
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START NOWThe roles of Industrial Symbiosis
Industrial symbiosis is a collective process involving governments, local authorities, universities, trade associations and businesses. Within this ecosystem, the industrial symbiosis facilitator is the key figure who transforms theoretical opportunities into concrete collaborations, connecting companies and coordinating local stakeholders.
For companies, identifying a network with a qualified facilitator is the first step towards effective circular economy projects. For institutions, moreover, investing in the training of these professionals accelerates the transition towards more sustainable production models.
Who is an Industrial Symbiosis facilitator?
The facilitator is a strategic mediator who connects companies, institutions and stakeholders involved in industrial symbiosis projects. Unlike a traditional consultant, they do not propose standardised solutions. Instead, they act as a connector, coordinator and builder of trust between the parties.
Technical expertise in every industrial sector involved is not a prerequisite. Their core competence, rather, lies in creating and maintaining relationships of trust, mapping material and waste flows, identifying potential synergies, and supporting companies in overcoming organisational and cultural barriers.
As Marta Dal Farra’s interview highlights, the relational and trust-based dimension is often the real factor that determines whether a symbiotic project succeeds or fails. Barriers to symbiosis are, in fact, more often informative and relational than technical: there is frequently a lack of awareness of available opportunities, a lack of trust between potentially competing companies, and a lack of the systemic vision needed to recognise the value of the exchange.
Where a facilitator is present, however, the success rates of synergies increase significantly and implementation times are reduced. The role of the facilitator is therefore not merely optional, but a structural element for the development of functioning industrial symbiosis networks.
Examples of Industrial Symbiosis: case studies of excellence
The following examples — ranging from the best-known case in Kalundborg to initiatives in Italy and Sfridoo’s projects — demonstrate how the industrial symbiosis model has adapted to different geographical contexts, sectors and scales. In each case, the key principle remains the same: one company’s waste can become another’s resource.
Kalundborg, Denmark: the world’s first example of industrial symbiosis
It all began in Kalundborg, Denmark, in the early 1960s. A refinery and a thermal power station began exchanging water and steam purely for economic convenience, before the concept of industrial symbiosis even existed. From that initial agreement, a network has developed which now involves 17 partner companies and over 30 active exchange flows across different sectors: energy, pharmaceuticals, biotechnology and water management. Every year, the symbiosis saves around 4 million m³ of groundwater, recycles 62,000 tonnes of materials and results in an estimated saving of 586,000 tonnes of CO₂.
Kwinana, Australia: large-scale industrial symbiosis
The Kwinana industrial area in Western Australia demonstrates what happens when institutions and companies collaborate on a large scale. Operating since 1952 across 120 km², it is host to 47 active partnerships between 14 companies in the mining, refining, chemical and energy production sectors. The impact is significant: over 4,800 direct employees, 26,000 indirect jobs and an estimated economic contribution of 16 billion Australian dollars a year.
Industrial symbiosis in Europe: the UK and Finland
In Europe, the UK’s NISP (National Industrial Symbiosis Programme) was the first national of tis kind. Launched in 2005, it has involved over 15,000 businesses, saving 47 million tonnes of waste from landfill and avoiding 42 million tonnes of CO₂ emissions.
In Finland, the Digipolis technology hub has been coordinating the circular economy platform for the Arctic region of Kemi-Tornio since 2012. In that area, mines, paper mills and chemical plants generate 1.3 million tonnes of secondary waste streams per year, with an estimated symbiosis value of 200 million euros.
Industrial symbiosis in Italy: ENEA projects
In Italy as well, ENEA launched the “Eco-Innovazione Sicilia” project in 2011. This pilot scheme involved the creation of a database of local companies, the mapping of resource flows and, most importantly the implementation of Italy’s first industrial symbiosis platform, SYMBIOSIS, launched in 2014 and still active today.
The model was eventually extended to other Italian regions: Emilia-Romagna, Lazio, Marche, Lombardy, Campania and Umbria, where in 2017 over 50 companies shared around 250 resources, generating 260 potential synergies. In Umbria, these included the use of olive mill wastewater for the extraction of polyphenols for the cosmetics sector.
Sfridoo Case Studies
In this environment, Sfridoo acts as a facilitator between companies that generate waste and those capable of recovering it, transforming industrial waste flow into ongoing commercial relationships.
In the metalworking sector, one company was disposing of 2,300 tonnes of grinding mud every year, at a disposal cost of €391,000. Through the Sfridoo network, a partner capable of recovering the metal component was identified. As a result, the cost dropped to zero and the waste flow became a resource with market value.
In the agri-food sector, residues from the processing of melons and watermelons have been redirected to an anaerobic digestion plant for the production of biomethane.
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START NOWHow to implement Industrial Symbiosis
In the operating reality of businesses, creating synergies between companies faces real obstacles. Understanding these obstacles is, therefore, the first step towards overcoming them.
The most significant obstacles in a B2B context relate to access to information, technical feasibility, the regulatory framework, organisational culture and the economic viability of the initial investments.
On the data front, the problem is simple yet common: companies do not know what others produce, nor what they might be able to use. Without dedicated data management systems, opportunities for synergy remain hidden. On the practical side, the variability in the characteristics of industrial waste and the lack of adequate logistics infrastructure often make exchanges difficult to execute.
In Italy, one of the most frequently quoted obstacles is regulatory. The distinction between industrial waste and by-products is critical, since by-product can circulate between companies under simplified procedures. When this distinction is applied inconsistently, companies tend to abandon recycling routes to avoid legal risks. At a cultural and institutional level, moreover, the lack of trust between companies that do not know each other, combined with a shortage of dedicated skills, further slows down the establishment of partnerships.
Lastly, the perception of economic risk is holding back smaller businesses in particular. The costs of analysis and coordination are upfront, whereas the benefits — such as reduced disposal costs, new profits from waste, and access to secondary raw materials — only pay off in the mid-term.
The importance of digital platforms
Each barrier is matched by a corresponding driver. Industrial symbiosis projects that have delivered results share certain characteristics: the presence of a facilitator, shared information systems, regulatory clarity, and technological networks that support synergies.
Specialised digital platforms operate on multiple levels simultaneously: they make waste flow visible, connect supply and demand across different sectors and regions, reduce the costs and time involved in finding a partner, and lower the barrier to entry even for the smallest businesses.
Sfridoo is the marketplace dedicated to B2B industrial symbiosis. It connects companies that want to sell, recover or purchase industrial waste across a wide range of product categories, from wood to textiles, operating at both local and national levels. Every item of waste listed has the potential to become another company’s raw material.
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Enter the marketplace nowThe Future of Industrial Symbiosis
The world of industrial symbiosis is changing. More sophisticated digital tools, european legislation increasingly oriented towards circularity, and a growing awareness of the economic value of industrial waste are reshaping the possibilities of this model.
On the regulatory side, the European Commission has recognised industrial symbiosis as a key factor in decarbonising industry and reducing dependence on raw materials. It is explicitly included it in the European Green Deal, the programme aimed at achieving climate neutrality in Europe by 2050. Within this framework, the recovery of industrial waste is shifting from a voluntary choice to a systemic requirement.
At the same time, the digital revolution is significantly expanding the operational possibilities of symbiosis. The growth of circular economy platforms, the development of new material traceability systems and the introduction of the Digital Product Passport are making waste flow more visible, more documentable and easier to match between different companies. As highlighted by the analysis conducted by the SUN network, the Symbiosis Users Network promoted by ENEA, these developments will lead to an increasingly widespread use of technical standards, moving beyond local approaches to facilitate symbiosis networks on a larger scale.
There is, however, one aspect that technology and legislation alone cannot resolve: the relational aspect. Industrial symbiosis works because it involves multiple players simultaneously, and its potential grows in proportion to the quality of the networks it manages to build.
For companies operating in this sector today, the message is clear. Those who begin to map their industrial waste flows, document it and build structured relationships with other operators are not only reducing their management costs. They are, moreover, establishing a competitive position within a regulatory and market context that is rapidly taking shape around these principles.
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Caterina Bonafede
Sfridoo Staff
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