Travail de fin d'études en sciences et technologies de l'environnement : Environmental impact assessment of construction and demolition waste and municipal solid waste management through a life cycle assessment (LCA) for small island developing states (SIDS): a case study in Greater Malé area, Maldives.

Abstract

This study applies Life Cycle Assessment (LCA) to evaluate the environmental impacts of evolving waste management strategies in the Greater Malé area, Maldives, focusing on municipal solid waste (MSW) and construction and demolition (C\&D) waste. Two scenarios were compared: a pre-2017 baseline characterized by open dumping and burning, and a planned scenario featuring a new Regional Waste Management Facility (RWMF) integrating a Waste-to-Energy (WtE) plant and a C\&D waste processing plant. The functional unit is defined as the management of one tonne of mixed waste, with system boundaries encompassing collection, transportation, treatment, and final disposal. Waste flows were modeled using Ecoinvent 3.12 via openLCA 2.6.1 and assessed with the ReCiPe 2016 (midpoint) H method, complemented by normalization and Monte Carlo uncertainty analysis. Results reveal a clear hierarchy among impact categories. "Human toxicity: carcinogenic" is the dominant category in both scenarios, with a normalized score approaching 0.25, and remains largely unchanged due to chromium(VI) formation during high-temperature incineration and its long-term leaching from landfill residues. Marine and freshwater ecotoxicity, the second most significant cluster with a baseline score of approximately 0.115, are substantially reduced through advanced flue gas cleaning and fly ash extraction. All other categories display negligible normalized scores. The waste management scenario achieves reductions across 9 of the 18 assessed impact categories, driven primarily by avoided diesel-based electricity production. Inter-perspective variability across cultural perspectives represents a greater source of uncertainty than operational data variability.