| dc.description.abstract | During the production of alumina (aluminum oxide) at Bayer plant, bauxite residue results in the largest amount of waste produced at the industrial level. Over time, different treatments have been created to reduce the environmental impacts associated to its disposal, yet little information is known about the environmental performance of these operations. Firstly, this master thesis, Developed a Life Cycle Inventory (LCI) collecting input/output data associated with three different treatments of Bauxite residue occurring in European companies: Dry stacking by Alum in Romania, Dry disposal by Mytilineos in Greece, and Mud Farming by Aughinish in Ireland. Secondly, a Life Cycle Impact Assessment (LCIA) is carried out for each treatment. Due to NDA with each company, individual assessments are private, but a public analysis reveals how relevant the environmental impact of treating Bauxite residue is. The study is an operational LCA for the year 2020. The system boundaries consider since the Bauxite residue slurry exits the washers within the Bayer plant until the treated Bauxite residue is placed in the final Disposal Area. This research utilizes the Ecoinvent 3.6 environmental database for the inventory phase, SimaPro v 9.0 to run all the calculations in the LCIA phase, and ReCiPe 2016 ( midpoint, hierarchy) as the main impact method. The results discovered five main processes in treating bauxite residue: transport, dewatering, disposal, recovery and discharge. Among the inputs of the system, electricity, diesel, chemicals, trucks, and land are the most necessary, while among the outputs, the discharge of the bauxite residue is the only one covered. In terms of environmental impacts, the results identified dewatering generating the greatest environmental impact across 15 impact categories. The fossil fuels' input origins are the cause of their environmental burden. The discharge of metals within the solid part of bauxite residue is the major contributor to the three remaining impact categories: marine toxicity, human carcinogenic and human non-carcinogenic. Comparing the three treatments shows that one has more environmental impacts in most categories. With this full LCIA, it is possible to determine that although the other two treatments generally have lower impacts, they still have higher impacts in some impact categories (marine ecotoxicity, human toxicity and freshwater eutrophication). | |