Life cycle assesment of municipal solid waste management methods: Ankara case study O ¨ zeler D., Yetis U ¨ ., Demirer G.N. * Department of Environmental Engineering, Middle East Technical University, 06531, Ankara, Turkey Received 30 July 2005; accepted 6 October 2005 Available online 28 November 2005 Abstract Different solid waste management system scenarios were developed and compared for the Municipal Solid Waste Management System of Ankara by using the life cycle assessment (LCA) methodology. The solid waste management methods considered in the scenarios were collection and transportation of wastes, source reduction, Material Recovery Facility (MRF)/Transfer Stations (TS), incineration, anaerobic digestion and landfilling. The goal of the study was to determine the most environmentally friendly option of MSWM system for Ankara. The functional unit of the study was the amount of solid waste generated in the system area of concern, which are the districts of Ankara. The life cycle inventory analysis was carried out by IWM Model-1. The inputs and outputs of each management stage were defined and the inventory emissions calculated by the model were classified in to impact categories; non-renewable energy sources exhausting potential, final solid waste as hazardous and non- hazardous, global warming, acidification, eutrophication and human toxicity. The impacts were quantified with the weighing factors of each category to develop the environmental profiles of each scenario. In most of the categories, Source Reduction Scenario was found to be the most feasible management method, except the global warming category. The lowest contribution to GWP was calculated for the anaerobic digestion process. In the interpretation and improvement assessment stage, the results were further evaluated and recommendations were made to improve the current solid waste management system of Ankara. D 2005 Elsevier Ltd. All rights reserved. Keywords: Solid waste management; Life cycle impact assessment; Life cycle inventory analysis; IWM model-1; Impact categories 1. Introduction Life Cycle Assessment (LCA) has been defined by Society of Environmental Toxicology and Chemistry (SETAC) ‘‘as an objective process to evaluate the environ- mental burdens associated with a product, process or activity, by identifying and quantifying energy and materials used and waste released to the environment, and to evaluate and implement opportunities to effect environmental improvements’’ (Barton et al., 1996). LCA is a methodology for examining environmental impacts associated with a product, process or service FFfrom cradle to grave__ – from production of the raw materials to ultimate disposal of wastes. LCA was developed in order to take into account issues that are not addressed by other environmental management tools such as statutory environmental impact assessment. It has proved itself particularly useful as a technique for comparing two or more alternative options in terms of their combined potential environmental impacts and ecological sustainability. The methodology of LCA can be described by four interrelated phases, as shown in Fig. 1, namely goal and scope definition, Inventory analysis, impact assessment, and inter- pretation. The arrows in Fig. 1 imply that the phases are continuously interrelated. If there are some unsatisfactory and missing parts in one phase, which will affect the intended application of the whole study, then the other phases must be revised and improved. LCA has been used as an effective environmental management tool in many studies. For example, LCA was used to compare the environmental impacts of different automobiles (Graedel et al., 1995), to compare the environ- mental impacts of the use of key detergent builder systems (Morse et al., 1995), to lower the VOC content of paint in 0160-4120/$ - see front matter D 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.envint.2005.10.002 * Corresponding author. Tel.: +90 312 210 58 67; fax: +90 312 210 12 60. E-mail address: goksel@metu.edu.tr (G.N. Demirer). Environment International 32 (2006) 405 – 411 www.elsevier.com/locate/envint