Circular guide


Didactic Units 5.1

The closing of industrial cycles, in order to ensure the efficient use of resources and the mitigation of environmental impacts, turns out to be one of the founding principles of the circular economy. In this framework, the concept of industrial symbiosis and its implementation in practice turn out to be indispensable elements, in order to fully seize the opportunities posed by the transformation of the current production system. 

 The concept of industrial symbiosis is inextricably linked with industrial ecology as theorized by Robert Frosch in 1992. Analogous to natural ecosystems, according to Frosch, “industrial ecosystems” in addition to minimizing the waste produced by their activities, should in fact be able to reuse waste materials and products as much as possible, allocating them to new production processes. This analogy is further supported by the considerations, also elaborated in those years, by Robert Ayres: similarly to what happens in the biosphere where an efficient use of material resources and energy is observed the “technosphere,” imaginable as the place where industrial activities reside and operate, should be directed toward a redesign of its production processes in order to minimize harmful releases of unused by-products into the environment. The definition of industrial ecology that has thus emerged over the years, thanks to the contribution of numerous studies and publications on the subject, thus provides a large-scale integrated vision that envisions the future design of industrial infrastructure as a series of interconnected ecosystems interfaced to the global ecosystem. 

 Coming to the concept of industrial symbiosis, this can be defined as a strategy of optimizing resource use, applied through the involvement of traditionally separate industries, aimed at generating and promoting competitive advantages from the transfer of matter, water, energy, by-products, space and skills. The application of the principles underlying this approach obviously guarantees possible benefits that can be traced to the environmental, economic and social spheres: first, the environmental benefits, are derived from the optimized use of resources with the consequent mitigation of environmental pressures associated with more traditional industrial models; the economic benefits, on the other hand, are to be found in the improvements that can be achieved at the industrial process level, in the reduction of raw material procurement costs and in the creation of new market opportunities; lastly, the social benefits are attributable to the possible positive spillover effects in terms of employment and local development. 

 Once the concept is framed, a question then arises: how can industrial symbiosis strategies be translated into practice? The implementation of the latter can be carried out on the basis of different operational models, described below in their most characteristic features:  

  • Industrial Districts, which represent the development of industrial symbiosis mechanisms in territorial areas, typically based on a “bottom-up” approach in that they are developed as a result of the creation of a system of entrepreneurial relations, independently of specific urban or industrial planning, but on the basis of spontaneous agreements for the realization of exchanges of materials, energy or services; 
  • Eco-industrial Parks, which are instead based on a “top-down” approach being developed from sectoral regulatory initiatives; 

Networks for Industrial Symbiosis, the latter of which can be defined as tools aimed at facilitating the matching of demand and supply of resources between different interlocutors who, on the basis of their economic activity, would not otherwise have an opportunity to meet.

Industrial symbiosis: regulatory interventions in Europe and Italy 

The potential offered by industrial symbiosis has been the subject of a number of regulatory interventions, found at both the European and national levels.

At the EU level, already since Communications COM (2011) 571 (Roadmap to a Resource Efficient Europe), COM (2014) 398 (Towards a Circular Economy Zero Waste Europe Program) and COM(2015) 614 (The Missing Link – European Union Action Plan for the Circular Economy), industrial symbiosis is recognized as a key building block to stimulate new production models, aimed at ensuring rational and efficient use of resources, with the possibility for the European economy, to exploit its benefits in environmental, economic and social terms. The contents of the aforementioned communications were subsequently incorporated into the Circular Economy Package approved on April 18, 2018 by the European Parliament and revised more recently, following the presentation of the European Green Deal, last March. In the latter document with reference to the development of industrial symbiosis processes at the community level, the importance of the implementation of a specific reporting and certification system promoted by the industrial sector is emphasized, in order to encourage and improve the use of by-products in the aforementioned industrial processes. 

 Turning to our country, in addition to the transposition of the previously mentioned directives, it is possible to mention some specific measures aimed at ensuring the development of such practices. Particular importance can be attributed to Legislative Decree 112/1998 in which Article 26 introduces into the national system the Ecologically Equipped Productive Areas (APEAs), the regulation of which is delegated to the regions, and defined as industrial areas equipped with the necessary infrastructure and systems aimed at ensuring the protection of health, safety and the environment. The establishment of such areas provides for the achievement of high environmental ecological standards as well as the organic management of facilities and services designed to reduce pressures on natural resources resulting from production activities, prevent all forms of pollution, and protect health and safety. To date there are 10 regions, which have already legislated on APEAs (Abruzzo, Calabria, Emilia-Romagna, Liguria, Marche, Piedmont, Apulia, Tuscany, Sardinia and Lazio). Among these, Tuscany attracts particular attention, as it represents one of the most advanced examples on the regulatory development front on this matter. As early as the end of 2009, in fact, the region had its own certification system for the aforementioned industrial areas, established through Regional Regulation 74/r and the Deliberation of December 28, 2009, in which the criteria for defining the environmental performance of APEAs are established. Through these regulatory acts, the region of Tuscany in fact establishes that, in order to obtain APEA status, these areas will have to meet a series of minimum requirements of an urban-building, infrastructural and managerial nature. 

 For other regions, on the other hand, the situation appears to be quite varied, with some of them such as Sicily and Friuli-Venezia Giulia having developed other regulations aimed at facilitating the environmental management of production areas, to which can be added cases in which legislation on the subject is either completely absent or being implemented.

Examples of industrial symbiosis: the case of Kalundborg and Italian industrial districts 

The opportunities posed by the development of industrial symbiosis systems are already witnessed by some realities that have become established over the years. At the community level for example, particularly relevant is the case of the Kalundborg industrial park located in Denmark, which represents one of the best known industrial districts well beyond European borders. The reality of Kalundborg has been developing since as early as the 1960s, as a result of the establishment of a dense and complex network of material and energy exchanges between players in the chemical, energy, biotechnology, construction, water and waste management sectors. Following a “bottom-up” approach, the collaborations that have arisen over the years have not developed as a result of specific urban and industrial planning, but in an almost physiological manner: in fact, these have been created as a result of initiatives by individual actors moved by the desire to exploit the economic benefits arising from the development of the possible synergies that can be activated. 

Figure I Representative diagram of the Kalundborg industrial district.

A critical issue that the Kalundborg district has faced since its inception concerns the scarcity of water resources: this, according to some studies, was in fact one of the main causes that triggered the emergence of the first forms of collaboration. Among the symbiosis processes established, one of them involves precisely water and specifically that coming from the district’s refineries, which, following purification processes, is destined for the Asnaes power plant to be used in the cooling of the plants. The model proposed by the Danish district, is also based on the exchange of energy, operated through district heating provided by the power plant itself, to the municipality of Kalundborg and the other companies that are part of the network, such as those operating in the fish farming sector that use the heat given off to heat the water of their farms. 

 Among the by-products generated by the plant are more than 70,000 tons of ash that are resold to the cement industry, which is able to reuse them in its own production processes. Added to this is the waste of sulfur dioxide, which, once transformed into calcium sulfate (gypsum), is then used by local companies involved in plasterboard production. 

 Finally, other symbiosis processes, involve a number of companies active in the biotechnology sector such as Novo Nordisk, whose waste sludge from some biological processes is destined for neighboring farms for use as agricultural fertilizer. The complexity and number of flows involving matter and energy, only hinted at here, testify to the great opportunities arising from the application of symbiotic industrial models: first, the economic benefits from the valorization of one’s own waste and scraps, which in a linear economy model would otherwise be seen as costs, are evident, to which are added the innumerable environmental benefits in terms of saving virgin raw materials and pollution; second, the possibility of combining economic growth and attention to sustainability is reconfirmed by the above example.

Similar to the European examples, some more or less successful examples of implementation of collaborative practices between entrepreneurial entities can also be found in our territory. Specifically in Italy, more than 141 production districts have been created over the years, arising primarily as a result of the needs related to the management of their own waste, on which still persist in our country, some critical issues. These districts are defined as production areas, with a high concentration of small and medium-sized enterprises (SMEs) marked by a high level of specialization, a strong interdependence of their production processes and a marked integration with the territorial context in which they are located. Similar to the production of goods and services, the management of by-products and waste should also be oriented in this direction, as witnessed by some emblematic cases.

In this sense, the Brescia district represents an initial demonstration, in which, thanks to the collaboration established between local Confindustria and the Conou consortium, a complex network of mineral oil collection and recycling has been created. Through such collaborations, more than 5,000 tons of industrial oil have been collected and sent for recycling. Among the industrial districts formed in Italy, it is also possible to mention the case of the leather district of Santa croce sull’Arno and from the more famous textile district of Prato. The former is characterized by the production of leather and hides used in sectors such as furniture, leather goods and the fashion industry in general. The most characteristic element of the district lies in the shared management by local companies, of wastewater which is collected and managed in a single centralized purification plant. The second example, on the other hand, represents to date one of the cutting-edge models in the recovery of materials from used clothing, but at the same time testifies to some of the difficulties encountered in the implementation of virtuous practices due to current regulations. In fact, this experience has enabled the development of a symbiosis system aimed at processing more than 180 thousand tons per year of textile waste and more than 50 thousand tons of waste and leftovers, which, however, are currently still classified as waste. Therein lies an obvious legislative problem, which undermines the proper implementation of the principles of circular economy and more specifically of industrial symbiosis. Waste in fact turns out to be to all intents and purposes by-products, according to the requirements of Article 184-bis of Legislative Decree 152/2006, as they come directly from production processes and do not pose any risk to the environment and health. Unfortunately, however, current regulations, by providing for them to be characterized as waste, prevent their immediate reuse in looms. The situation that is thus being generated has obvious negative repercussions in economic and environmental terms first and foremost, as it leads to increased costs for companies and inefficient use of a resource that could otherwise be used again.

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