An Investigation into optimising water flow of industrial symbiosis : development and application of a model

Abstract

The concept of Industrial Symbiosis (IS) has obtained world concern as a new initiative for achieving collaborative benefits through exchange of resources between industries including water. Even though, these initiatives became prominent as successful projects in the early stages, many of them have resulted in failures in the long term without achieving the expected results due to deficiencies in IS planning. In the current process, no prior evaluation and optimisation are taking place before implementing the identified water synergies. There is therefore a need to have a standardised method to assess the optimum water flow of IS. Accordingly, the current study aimed to develop a model to assess the optimum water flow of IS. In order to achieve the aim, the research stands within the pragmatism philosophical stance. The abductive approach was applied as the appropriate research approach. Sequential exploratory research design was adopted consisting three phases: Phase I: Desk study; Phase II: Interviews with industry experts; and Phase III: Case study. Phase I - Desk study was conducted to collect and review the data from reliable published sources to identify water inputs and outputs of industrial entities. Based on the key literature reviewed, the conceptual model was developed by integrating mathematical formulae. In Phase II, sixteen interviews were conducted with industry experts in Sri Lanka to collect the data. The collected data were analysed using the code-based content analysis technique with the application of QSR International’s NVivo. 12. As key findings derived from analysis, current methods & issues of industrial water management and enablers & barriers for initiating water exchange networks in Sri Lanka were identified. Furthermore, the conceptual model and mathematical formulae were also refined to the selected context. The applicability and feasibility of the model were evaluated during Phase III. An IS network in an export processing zone (EPZ) in Sri Lanka, comprising three geographically co-located industrial entities, was selected as a suitable case study. Seven semi-structured interviews were conducted with professionals within the selected case to collect the data, which were analysed using the mixed integer linear programming (MILP) approach. The assessment model was developed and tested using SageMath software. Finally, environmental, economic and social feasibility of the developed model were also determined. The developed model forms a unique foundation for assessing the optimum water flow of IS, applying in any context subject to context-specific enhancements. The novelty of the current research is its objective of reducing freshwater consumption of the IS network through maximum wastewater recovery in assessing the optimum water flow of IS. Thus, the research outcomes provide a role model for all developed and developing countries for reducing the environmental impact of industrialisation through optimum water sharing between industrial entities.