Design and Planning of Sustainable Industrial Networks: Application to a Recovery Network of Residual Products

The present work describes the integration of environmental impact/damage evaluation into an optimization model for management of industrial networks. The selected methodology of environmental evaluation, the Eco-indicator 99, is based on the life cycle impact assessment. Its implementation and suitability is studied with an emphasis being placed on the strengths and limits of the methodology. The final model, derived from the application of process system engineering methodologies, is described as a mixed-integer linear program, which, once solved, is able to suggest the optimal processing and transportation routes, while optimizing a given objective function that either meets the design and environmental constraints or minimizes the eco-indicator. Whenever the impacts/damages costs are quantifiable, the calculation may also contemplate the inclusion of the environmental costs into the economic function that evaluates the network characteristic data and costs. An example based on the implementation of an innovative network for the recovery of the sludge obtained from aluminum surface finishing plants is presented. This illustrates the importance of including environmental impact/damage methodologies, explores their possible uses and analyzes obtained results. It is also used to perform a multiobjective analysis through an approximation to the Pareto curve for an economic-environmental trade-off. This curve is obtained through the application of a ε-constraint method, by plotting a set of successive optimized solutions given by the maximization of an economic function that reflects the costs of disposal, processing, transport, and materials storage versus an impact indicator obtained from the environment pollutants emitted. This analysis is complemented with the minimization of the eco-indicator value (EI99), along with an estimate of the corresponding amount of sludge recovery.