SOLID WASTE MANAGEMENT: A SYSTEMS APPROACH

This study presents an integrated methodology for decision-making regarding the selection of the appropriate set of methods to face MSW management problems on the basis of local waste stream features, engineering feasibility, socio-economic constraints and societal concerns on key issues such as public health and ecosystem protection. The most relevant state-of-the-art MSW treatment technologies and their general characteristics have been collated and critically reviewed. Composite indicators coupling technical and economic performance with societal needs have been developed to characterize the different technological options. Using decision theory techniques the updated knowledge base has been organized into a systematized decision support system that provides a realistic description and assessment of the overall waste management system. This approach has been applied for the selection of the technological methods in order to successfully tackle the waste management problem in Eastern Attica, Greece. SWOT analysis was used to develop qualitative attributes of the different technological options after having first analyzed their technical and economic feasibility. Based on the outcome of the integrated method developed herein biological and mechanical treatment is deemed to be the most appropriate when considering the volume, chemical composition and properties of the respective waste streams as well, as the local population sensitivities. The final system proposed was a combination of aerobic digestion with composting for 75% of the organic waste and anaerobic digestion for the residual 25%. This integrated process would produce refuse-derived fuel, high quality compost and biogas while reducing the residue volume to less than 20% of the original. The residual waste could be treated in sanitary landfills. The investment cost for a plant capacity of 400 ktn/yt would be 97 m(sic) and the annualized operational cost would be ca. 15 m(sic). Income from sales of effluents and the produced energy could easily exceed 15 m, thereby rendering the overall investment profitable.