Integrating life cycle assessment and multi criteria decision making for sustainable waste management: Key issues and recommendations for future studies

Decisions on waste management systems are subjected to multiple sustainability criteria, including environmental, social, and economic criteria. Decision makers therefore can benefit from systematic approaches to evaluate different waste management options considering multiple sustainability criteria. This study reviews multi criteria decision making (MCDM) and life cycle assessment (LCA) approaches that assess the sustainability of waste management systems. We present a framework for integrating LCA-MCDM approaches. First, we identified the most used MCDM methods for waste management systems published in the literature and highlight the technical and sustainability criteria used in the literature. Then, key issues in LCA studies of waste management systems were reviewed and discussed. The review results indicated that there are only a limited number of studies that integrated LCA and MCDM to assess the sustainability of waste management systems. Furthermore, more than half of the studies that did use the integrated approach failed to consider all three pillars of sustainability. There is also a lack of detailed information on the life cycle inventory used for the LCA part which reduces the reproducibility and clarity of the studies. In addition, the normalization and weighting methods to convert environmental impact categories for each scenario into single scores were often neither clearly explained nor justified. Also, the detailed information about experts involved in the decision-making process as well as the procedure of acquiring their opinions were not fully presented. Finally, the LCA and MCDM approaches, relevant sustainability criteria and related standards were used to present a set of recommendations for performing an integrated LCA-MCDM study that ensure scientifically robust, meaningful and reliable decisions.