Developing sustainable local systems through Industrial Symbiosis: the cases of Agro-Industrial and Urban contexts

Industrial Symbiosis (IS) is an environmental business practice and one of the founding notions within the interdisciplinary field of Industrial Ecology (IE). It describes the operation of communities of firms, from various industrial sectors and of various sizes, where the by-product/waste of a company serves as a raw material for one or more organizations in the same network, obtaining both environmental and economic benefits connected to the improved efficient use of materials and energy. Since the concept of IS emerged, many forms of IS implementation have been identified in different places. Indeed, there are many different local contexts that could be associated with different forms of the IS model. Comparing these forms and their relationships with the places where they occur is challenging because a comparative analysis of IS experiences in different national contexts, involves finding concepts that identify equivalent empirical phenomena in different countries. It is therefore difficult to begin to generalise the processes by which IS has developed and the extent to which the conditions necessary for it to flourish are generalisable. Considering these complexities, in this paper, the key findings of different authors that have dealt with the classification and characterization of IS systems are put together. Leaving aside a common and specific definition of IS, as well as the influence that local circumstances may have on the form in which IS may take place (on which a significant scientific debate persist), this paper aims to identify the main general attributes that an IS network may satisfy. Then an evolutionary path toward sustainable local systems for the specific cases of agroeco- industrial and urban context is presented, in order to verify the role played by the identified attributes. The evolutionary approach looks at how companies/organizations respond to the external economic, social, cultural and environmental changes. Three main stages of evolution are identified, based on the literature, representing progressive network of an IS network. Type I is a linear immature system which includes firms that have no connections with each other, even if they operate geographically close; type II describes a system in which the previously isolated actors start to co-operate, also including other companies and creating new shared activities; type III is a mature system with roundput material and energy flows, characterized by a high degree of diverse exchange relationship between firms, but also by links with firms external to the system boundaries. The analysis highlights that differences and specificities for each case of IS exists, but also that the evolutionary path seems to confirm the role of the identified attributes and that common situations may be identified for the development of sustainable local systems.