Francesco Di Maio

An approach to LCSA: the case of concrete recycling

PurposeThe framework of life cycle sustainability analysis (LCSA) has been developed within the CALCAS project but the procedure on how an LCSA should be carried out is still far from standardized. The purpose of this article is to propose an approach to put the LCSA framework into practice. This approach is illustrated with an on-going case study on concrete recycling.MethodsIn the context of an EC-FP7 project on technology innovation for concrete recycling, five operational steps to implement the LCSA framework are proposed: (1) broad system definition, (2) making scenarios, (3) defining sub-questions for individual tools, (4) application of the tools and (5) interpreting the results in an LCSA framework. Focus has been put on the goal and scope definition (steps 1–3) to illustrate how to define a doable and meaningful LCSA. Steps 4–5 are not complete in the case study and are elaborated theoretically in this paper.Results and discussionThe experience from the case study shows that the operational steps are especially useful at the stage of defining the goal and scope. Breaking down the sustainability questions into different scales and different aspects gives the possibility to define the sub-questions suitable to be assessed by the individual analytical tools (e.g., LCA, LCC, SLCA, MFA, etc.). The C2CA-LCSA shows a practical approach to model the life cycle impacts of the broad system is to start by modelling the technological system at the micro level and then scale it up with the realistic scenario settings that are generated with the knowledge gained from the MFA studies at the meso-level and from the policy/economic studies at the macro level. The combined application of LCA, LCC and SLCA at the project level shows not all the cost items and only one social impact indicator can be modelled in the process-based LCA structure. Thus it is important to address the left out information at the interpretation step.ConclusionsDefining sub-questions on three different levels seems most useful to frame an LCSA study at the early stage of goal and scope definition. Although this study provides some useful steps for the operationlisation of the LCSA concept, it is clear that additional case studies are needed to move LCSA into a practical framework for the analysis of complex sustainability problems.

Recycling-oriented characterization of polyolefin packaging waste.

Packaging waste is one of the main sources of secondary polyolefins. It is essential to characterize polyolefins derived from this waste stream in such way, that not only mechanical sorting methods can effectively separate, but also that on-line sensor systems can quantitatively assess their distribution. The characterization methodology is hierarchical, relating all properties of waste particles in any phase of the processing ultimately to the input End-Of-Life products. The present paper documents a pre-concentrate obtained by hand picking of mixed Romanian household waste. Investigations have been addressed to identify the composition of this polyolefin waste stream, to study the polyolefin density distribution, to distinguish the polymer manufacturing methods (i.e. injection molding and blow molding) by flake physical properties and finally to perform all the required characterization and identification by hyperspectral imaging. On the basis of these analyses, polyolefins from packaging wastes can be recycled by density separation and their rheological properties and wall thickness indicate the molding procedures. Hyperspectral imaging based procedures have been also applied to set up quality control actions for recycled products.

Quality control in the recycling stream of PVC from window frames by hyperspectral imaging

Polyvinyl chloride (PVC) is one of the most commonly used thermoplastic materials in respect to the worldwide polymer consumption. PVC is mainly used in the building and construction sector, products such as pipes, window frames, cable insulation, floors, coverings, roofing sheets, etc. are realised utilising this material. In recent years, the problem of PVC waste disposal gained increasing importance in the public discussion. The quantity of used PVC items entering the waste stream is gradually increased as progressively greater numbers of PVC products approach to the end of their useful economic lives. The quality of the recycled PVC depends on the characteristics of the recycling process and the quality of the input waste. Not all PVC-containing waste streams have the same economic value. A transparent relation between value and composition is required to decide if the recycling process is cost effective for a particular waste stream. An objective and reliable quality control technique is needed in the recycling industry for the monitoring of both recycled flow streams and final products in the plant. In this work hyperspectral imaging technique in the near infrared (NIR) range (1000-1700 nm) was applied to identify unwanted plastic contaminants and rubber present in PVC coming from windows frame waste in order to assess a quality control procedure during its recycling process. Results showed as PVC, PE and rubber can be identified adopting the NIR-HSI approach.

FT-IR spectroscopy and Hyperspectral Imaging applied to post-consumer plastic packaging characterization and sorting

Post-consumer plastic packaging waste represents one of the main source of recovered polymers. A big problem now arising is thus the need to certify, in a fast (i.e. “on-line”) and reliable way, recovered plastic composition, as well as to assess polymer mixtures bulk characteristics, in order to partially, or totally, re-use them. The study is addressed to utilize a new technique, HyperSpectral Imaging (HSI) based, in order to identify polymers as resulting from a recycling process. This approach was specifically adopted to identify the presence of PolyVinyl Chloride (PVC) in the heavy fraction resulting from an industrial sink-float process. PVC detection is important because heavy fraction recovery is finalized to its further re-utilization as Solid Recovered Fuels (SRF). The presence of this polymer, in fact, for its chlorine content (i.e. dioxin production during combustion) negatively affects the thermal recovery of these products. The study demonstrated as the proposed HSI based approach, in the NIR range (1000-1700 nm), can successfully utilized to set up “real time” analytical/control strategies to perform a continuous monitoring of the composition of the different flow plastic waste streams obtained by from industrial processing, with particular reference to PVC identification.

FT-IR Analysis and Hyperspectral Imaging Applied to Postconsumer Plastics Packaging Characterization and Sorting

Postconsumer plastics packaging waste represents one of the primary source of recovered polymers. One of the main problem now arising is thus the need to certify, in a fast (i.e., online) and reliable way, recovered plastics composition, as well as to assess polymers mixtures bulk characteristics, in order to partially, or totally, reuse them. This paper is addressed to verify the possibility offered by a new technique, hyperspectral imaging (HSI)-based, in order to perform a real-time online identification of polymers as resulting from a recycling process. This approach was specifically adopted to identify the presence of polyvinyl chloride (PVC) in the heavy fraction resulting from an industrial sink-float process. PVC detection is important because heavy fraction recovery is finalized to its further reutilization as solid recovered fuels. The presence of this polymer, in fact, for its chlorine content (i.e., dioxin production during combustion) negatively affects the thermal recovery of these products. This paper demonstrated as the proposed HIS-based approach, in the near-infrared range (1000-1700 nm), can be successfully utilized to setup real-time analytical/control strategies to perform a continuous monitoring of the composition of the different flow plastic waste streams resulting from industrial processing, with particular reference to PVC identification.