Abstract In this study, the decision-making process for seawater desalination and its possible use in industry are addressed. Six desalination technologies were considered: multistage instantaneous distillation, multiple effect distillation, vapor compression distillation, reverse osmosis, electrodialysis, and nanofiltration. The problem was analyzed from several perspectives, including the evaluation of environmental, technical, and economic criteria, which were broken down into eight sub-criteria. The alternatives were evaluated considering three different multi-criteria decision-making (MCDM) methodologies: AHP, ELECTRE, and TOPSIS. The results show that the best option for desalinating seawater is reverse osmosis, followed by nanofiltration, thermal desalination methods, and lastly, electrodialysis. The results for the different methods showed the same ranking and no major discrepancies. It is concluded that desalination using membranes is a good option that could be used to supply water for various purposes, such as in industry.

Resumen Este estudio trata la toma de decisiones para la desalación de agua de mar y su posible uso en la industria. Considera la evaluación de seis tecnologías de desalación, como destilación instantánea de múltiple etapa, destilación múltiple efecto, destilación por compresión de vapor, ósmosis inversa, electrodiálisis y nanofiltración. Toma en cuenta criterios ambientales, técnicos y económicos, y desglosados en ocho subcriterios. Se usan los métodos de optimización multicriterio (MCDM): AHP, ELECTRE y TOPSIS. Se determinó que la mejor alternativa para desalar agua de mar es la ósmosis inversa, seguida por la nanofiltración, luego los métodos térmicos de desalación y, en último lugar, la electrodiálisis. Los resultados mostraron el mismo ranking sin mayores discrepancias. Se concluye que la desalación mediante membranas es una buena opción para abastecer de agua para diversos usos públicos, por ejemplo a pequeños agricultores, en zonas donde existe escasez de este recurso.

Management of the operations in a copper smelter is fundamental for optimizing the use of the plant's installed capacity. In the refining and casting stage, the operations are particularly complex due to the metallurgical characteristics of the process. This paper tackles the problem of automatic scheduling of operations in the refining and casting stage of a copper concentrate smelter. The problem is transformed into a flexible flow shop problem and to solve it, an iterative method is proposed that operates in two stages: in the first stage, a sequence of jobs is constructed that configures the lots, and in the second, the constructed solution is improved by means of simulated annealing. Fifteen test problems are used to show that the proposed algorithm improves the makespan by an average of 9.42% and the mean flow time by 12.19% with respect to an existing constructive heuristic.