Simona Scalbi

Use of Incinerator Bottom Ash for Frit Production

Summary This article presents the results of an experimental activity aimed at investigating the technical feasibility and the environmental performance of using municipal solid waste incineration bottom ash to produce glass frit for ceramic glaze (glaze frit). The process includes an industrial pretreatment of bottom ash that renders the material suitable for use in glaze frit production and allows recovery of aluminum and iron. The environmental performance of this treatment option is assessed with the life cycle assessment (LCA) methodology. The goal of the LCA study is to assess and compare the environmental impacts of two scenarios of end of life of bottom ash from municipal solid waste incineration (MSWI): landfill disposal (conventional scenario) and bottom ash recovery for glaze frit production (innovative scenario). The main results of the laboratory tests, industrial simulations, and LCA study are presented and discussed, and the environmental advantages of recycling versus landfill disposal are highlighted.

A method for improving reliability and relevance of LCA reviews: The case of life-cycle greenhouse gas emissions of tap and bottled water

The purpose of this study is to propose a method for harmonising Life Cycle Assessment (LCA) literature studies on the same product or on different products fulfilling the same function for a reliable and meaningful comparison of their life-cycle environmental impacts. The method is divided in six main steps which aim to rationalize and quicken the efforts needed to carry out the comparison. The steps include: 1) a clear definition of the goal and scope of the review; 2) critical review of the references; 3) identification of significant parameters that have to be harmonised; 4) harmonisation of the parameters; 5) statistical analysis to support the comparison; 6) results and discussion. This approach was then applied to the comparative analysis of the published LCA studies on tap and bottled water production, focussing on Global Warming Potential (GWP) results, with the aim to identify the environmental preferable alternative. A statistical analysis with Wilcoxons test confirmed that the difference between harmonised GWP values of tap and bottled water was significant. The results obtained from the comparison of the harmonised mean GWP results showed that tap water always has the best environmental performance, even in case of high energy-consuming technologies for drinking water treatments. The strength of the method is that it enables both performing a deep analysis of the LCA literature and obtaining more consistent comparisons across the published LCAs. For these reasons, it can be a valuable tool which provides useful information for both practitioners and decision makers. Finally, its application to the case study allowed both to supply a description of systems variability and to evaluate the importance of several key parameters for tap and bottled water production. The comparative review of LCA studies, with the inclusion of a statistical decision test, can validate and strengthen the final statements of the comparison.

Life Cycle Assessment as a tool for water management optimization in textile finishing industry

In several countries, due to the increasing cost and shortage of water, textile finishing industries are looking for non conventional water resources. The use of reclaimed wastewater appears a technically feasible solution and is gaining a growing consensus. A European Union research project (TOWEF0, Towards effluent zero) with the aim of elaborating a multicriteria integrated and coherent methodology to support the implementation of sustainable water reuse in textile finishing processes has been recently concluded. In order to achieve an optimal compromise between minimization of environmental impacts of the production processes and maximum recovery of resources, Life Cycle Assessment (LCA) methodology has been applied to selected textile products manufactured within Belgian and Italian textile finishing companies. The study identified the key environmental issues within the finishing processes of a variety of natural (cotton, silk) and man-made (polyester, acetate, viscose) fibers and fabrics and analyzed alternative water reuse scenarios. Significant margins exist for impressive reductions in water consumption with almost no additional environmental impact adopting in situ membrane filtration technology. In this paper the methodological approach and the results of the LCA analyses applied to a flax-polyester product are presented and discussed.