1. Introduction
Industrial Symbiosis (IS), a sub-field of Circular Economy (CE), promotes numerous connections between companies (so-called synergies), mostly located with physical proximity to one another, to exchange materials, energy, infrastructures, knowledge, and services to promote mutual environmental, social, and economic benefits [
1]. Symbiotic exchange can also happen within the same enterprise, among different processes, where the surpluses are valorized internally.
IS is one of the basic premises of Circular Economy, to create a circular system that envisages to incorporate the surplus from one industry into the production cycle of another industrial process as a substitute for raw materials, with the result of keeping resources in productive use for longer periods [
2]. The application of IS mitigates the footprint of the involved industries, the magnitude of its production impacts, and waste disposal costs [
3].
In the last decade, there has been an increase in the number of studies concerning the CE practices and IS implementation tools [
4]. Considering the proven benefits and the potential of IS, it is crucial to stimulate its implementation to foster sustainable development for the industry [
5]. Nevertheless, there is a set of intervening factors, that can work as barriers that restrict, or as enablers that foster the IS implementation at a large scale [
6]. Islam [
7], Golev et al. [
6], and Doroteya et al. [
8] have identified several industrial symbiosis barriers, which could be technological, economic and financial, lack of information, absence of trust among organizations, lack of commitment with sustainable development, regulatory (laws and regulation), and risk and uncertainty. On the other hand, in line with the dismissal of hindrances, a system of incentives is considered as an encouragement to facilitate the IS implementation for communities, companies, and entities [
9,
10].
To overcome the technical/technological barriers, which plays a major role in advancing IS and CE implementation [
8], several methods and tools have been reported in the literature [
11]. Moreover, a great number of tools are relevant to boost the CE, for example: process modelling tools and methods, that can help mathematize, simulate and optimize conditions of industrial systems and identify potential resources to be linked [
12]; mapping of industries and potential users [
13]; optimize networks of resource exchanges [
14]; applying Lean in the waste management to optimize the process [
15]; and assess the environmental, economic and social impacts of synergies [
14,
16,
17,
18,
19,
20,
21]. Moreover, Sustainable Consumption and Production (SCP) tools provide a set of methods and guides to support companies move to a more sustainable consumption and production [
22], for example, Product Environmental Footprint (PEF) and Environmental Management System (EMS) can support companies in the identification of strategies and scenarios for waste valorization [
4].
Looking exclusively at IS, in the last years it is noticeable the tendency to develop Information and Communication Technology (ICT) based tools that function as a platform embedding recommender systems, facilitating the matchmaking and mimicking of synergies [
23], emerging as a result of research and innovation funding or private developments [
24,
25]. So far, IS tools have been developed responding to five fundamental stages: preliminary assessment, engage business, find synergy opportunities, determinate feasibility, implement transactions and documentation. This characterization of areas has been an adapted result of several studies developed on this subject [
25]. The literature suggests that most of IS tools developed are concentrated in identifying opportunities/synergies and synergy assessment [
23]. According to the same study, the preliminary assessment phase is driven from a top-down perspective, and no study was found to assess the preliminary conditions or the potential of a company to engage in IS.
The concept of IS potential is referred to by scholars in a broad sense and is usually assessed for Eco-Industrial Park developments or at a regional scale by identifying wastes to be exchanged and by mapping of surrounding industries [
11,
18]. This analysis of potential is complemented, in a triple-bottom analysis, with the assessment of the potential impacts and benefits, gained through the implementation of IS, per synergy, or as a total of a site/region. However, there is also an opportunity to assess the preliminary conditions at a company level, and not only at a site or regional level. Therefore, the concept of IS potential, as described in this paper, is explored in the view of analysing the preliminary conditions to engage in IS.
In this alignment the aim of this paper is to present a tool that support companies in assessing their potential to partake in IS activities. This potential assessment combines the evaluation of the company’s current state regarding its performance in monitoring raw materials and surplus flows, the identification of surplus management practices including disposal and IS processes in case of existence, and the identification and comparison of the most valuable scenario for surplus valorization based on an economic perspective. Finally, a complementary identification of the company’s strengths, weaknesses, opportunities and threats that might positively or negatively influence the symbiotic process implementation is performed by a SWOT analysis to support the overcoming of barriers and enhancing the enablers for IS activities implementation.
The paper is divided into 4 sections.
Section 1 presents the context of the present work, the intended goals, and a literature review.
Section 2 describes the methodological approach of this work and an overview. In
Section 3 a detailed description of the tool modules and applications are presented.
Section 4 discusses the practical relevance of the tool and the current limitations. Finally,
Section 5 summarizes the main conclusions drawn from the developed work.
4. Discussion
The concept of potential for IS can take different approaches. While in the literature it is mainly being assessed at a regional level, for clustered networks or Eco-Industrial Parks, the potential for IS in the developed tool comprehends a new concept that covers the company framework, materials, and context. This concept aims to establish a new multicriteria perspective, more comprehensive and complete, considering the whole symbiotic process phases.
The existing approaches to determine the potential for IS are limited to the identification of symbiotic opportunities based on materials and surpluses, with its main focus on the development of procedures for matching and mimicking of synergies, not considering the integration with the company reality and its context [
25,
44].
The present study produced a schematic identification framework of the inputs and outputs of materials and surpluses as well as an integrated identification of the potential scenarios involved in the symbiotic processes.
The developed modules were developed to be complementary with each other and express an innovative approach when compared to other tools, by the analysis of the complete symbiotic process.
The identification module gathers relevant information for the company characterization in a symbiosis context and is the base for the following modules. The location will support future logistic decisions, the activity code will facilitate the search of potential synergies in existing sectorial databases, the company size will be important to define available funding and the environmental practices to establish the company commitment on environmental issues. This information is a crucial component for the surplus potential and to validate via crosscheck the information from the SWOT analysis.
The current state aims to analyze the monitoring level on materials and surpluses flow to establish improvement areas and promote resource efficiency, to potentially prioritize actions and identify the current processes associated to the surpluses’ management. The presence of current symbiotic processes allows its optimization and diversification on Module C while the absence of these processes directs the company to the beginning of the scope activities. The current state quantitative results facilitate the continuous improvement and the company periodic performance revaluation regarding materials and surpluses control and waste management processes.
Regarding the implementation potential, the valorization scenarios they were not limited to the identification of synergies but developed to support decision making by economic costs perspective comparison. Once defined the economic potential dimension of the surplus, it is essential to characterize the main factors that might positively or negatively influence the symbiotic process implementation. The SWOT analysis perform a non-material context analysis of the symbiotic process complementary to the previously developed modules, allowing to accurately and expeditiously identify the key factors that might affect the valorization implementation scenarios.
The flexible character of the tool, allows to receive data from available synergy identification tools, to facilitate scenarios diversification and support further comparison. Tools such as LCA and PEF could be complementarily used to support the decision-making of the most environmentally sound alternative, and considering the whole life cycle of the product as referred in [
4].
The IS potential assessment methodology derived from the study is currently under test and validation in some industries of the metalworking and retail sectors. Although the final results are not yet available, preliminary interaction with the companies attest the applicability to support them in three main fields: the identification of the main barriers to the implementation process that have to be addressed and considered by management level of the company; the support of internal decision making by reevaluation of implemented scenarios and simulation of potential alternatives based on cost perspective; the possibility to implement a continuous improvement performance at short, medium and long term strategy based on the actual state diagnosis module.
In case that the full set of scenarios defined for further comparison are not defined, its identification is highly dependent on background research.
The present tool is still not digitally integrated with complementary tools for synergy identification and cost assessment, resulting on a higher time-consuming process.
5. Conclusions
The presented tool demonstrates an innovative character, due to its unique methodological sequential approach regarding the assessment of the preliminary conditions of a company towards engaging in IS.
A dedicated logical framework and practical assessment tools, including data acquisition methods introduces an innovative concept for IS potential assessment by covering three different stages. The first regarding the actual practices and monitoring level on material flows and the implemented surplus management scenarios, the second focused on the comparison between different scenarios of surplus’ valorization based on a cost perspective analysis, and finally a complementary evaluation on the internal and external factors that can significantly influence the full process implementation.
The present tool allows to identify inefficiencies regarding material flows and surpluses management practices, facilitating the implementation of corrective actions and periodic performance assessments with a view to continuous improvement.
The characterization of the existing valorization alternatives based on their economic costs and their subsequent comparison, allows to support companies in decision making and simulation processes on the best scenarios from a cost benefit perspective.
The simplified identification of key internal and external factors associated to most relevant barriers on IS processes implementation allows the company to complement qualitatively their cost-benefit decision-making process analysis.
There is a high dependence on the reliability of data provided by industrials as well as the availability of data for the assessment of costs for new valorization scenarios. To assess the costs of alternatives scenarios implementation the stakeholder needs to estimate this value within external entities, in order to simulate and further compare with the different alternatives. However, in case of data unavailability, approximations on final expected costs can be necessary to overcome the lack and accuracy of data.
Another barrier which could extend or hinder the tool application is the lack of surplus’ categorization as by-product or residue, that can lead to an additional research activities. This classification is highly dependent on the implementation context and has to be considered. Moreover, the implementation records assessment is supported by available databases or existing documentation, nevertheless it could limit the potential for surplus scenarios identification in case of lack of recorded information publicly available.
The inclusion of environmental and social impacts in the final costs’ comparison will actively contribute to a more accurate decision making on the prioritization of the best scenarios.
The tool was designed to be applied in any industrial sectors and available surpluses, further validation in different sectors should be performed at project and implementation levels. Although, the standardization of this tool could be highly dependent on the legal national context, due to the different legislation regarding the surplus disposal and valorization. The full digitalization of the tool and the integration with intersectoral synergy databases, identification tools and cost calculation should be addressed in further research. A final cost-benefit viability analysis study and a suitable business model for the best scenario is recommended.