Industrial By-Product Reuse and Synergy Optimization

By-products synergy is a growing practice worldwide. It consists in the maximization of resources utilization with the replacement of raw materials by by-products as inputs for industrial processes. In order to support decision-making in such strategic projects, appropriate tools must be developed. This article presents the results of a research project, which includes the development of a multi-objective mathematical programming model for the optimization of by-products flows, synergy configurations and investment decisions in eco-industrial networks. This model is evaluated using data related to the Kalundborg industrial symbiosis in order to illustrate its utilization, as well as to assess, in a retrospective manner, the behaviour of the companies involved with respect to both economic and environmental benefits of synergies. The experiments also illustrate the influence of the municipality on synergy implementation, and how a scenario-based approach can be used to anticipate raw materials price increase. The results are generally coherent with the actual timing of synergy initializations. Furthermore, the considerable effect of water price on the length of investments' payback period illustrates the impact of policies and regulations on industrial symbiosis.