intermediate bulk containers re use in the circular economy an lca evaluation

Abstract The transition towards a circular economy, where the value of products, materials and resources is maintained for as long as possible, is an essential contribution to the European Union's efforts to develop a sustainable economy. Re-use of packaging items plays a key role in the achievement of this goal. The aim of this study is to assess the environmental impacts associated to the life cycle of Intermediate Bulk Containers (IBCs) as the number of uses (the so-called "rotations") changes, by using the life cycle assessment (LCA) methodology. The results of the contribution analysis show that the impacts of the life cycle of IBCs mainly come from the IBCs manufacturing, whereas the reconditioning process accounts for less than 20% of the overall impacts. Moreover, the system where IBCs are reconditioned and re-used has better environmental performance than the system where IBCs are used only once and then sent to recycling/disposal. The advantages of such a system increase with the number of rotations

LCA of food waste management in Italy, with a special focus on the effect of the bags used for the collection

More than 7 million tonnes of organic fraction were separately collected in Italy in 2018, following a robust increasing trend. Its treatment is progressively shifting towards anaerobic digestion instead of composting, with about 3 million tonnes currently being processed in integrated anaerobic/aerobic treatment plants or in purely anaerobic ones. The type of bag used for the organic waste collection is crucial in determining the overall performance of the system, since there is a mounting evidence that bioplastic bags, especially in the form of shoppers, might cause problems during the anaerobic treatment. On the other hand, paper bags allow for a smoother operation of the plant, since they don’t need to be removed upstream. This project aims to analyse the environmental performances of the full treatment chain of the organic waste processed with anaerobic digestion, starting from the assessment of the weight losses during the household storage, and considering the different behaviour of the bags at the treatment plant. In particular, the degradation potential and the corresponding biomethane production of the different typologies of bag were evaluated at the laboratory level, by means of BMP (Biochemical Methane Potential) tests carried out under different conditions. To assess the performances of the overall organic waste treatment chain, a comparative Life Cycle Assessment for the different types of collection bag (paper bags, bioplastic bags dedicated to the food waste collection, bioplastic shopper bags that can be reused for the food waste collection) was carried out. The following stages were included: the production and supply of raw materials used for the manufacturing of the collection bags and their packaging, the bags production, their distribution, their use at the household, and the collection and treatment of the food waste. As regards the latter, an anaerobic digestion process followed by post-composting was considered, including the valorization of useful outputs and the management of residues. For the recycling and recovery processes, two different modelling approaches were considered: the Circular Footprint Formula applied to Product Environmental Footprint (PEF) studies and the approach applied in the framework of the International Environmental Product Declaration (EPD) System. The results revealed how the use of paper bags for the storage of food waste generally leads to improvements in the impact associated to its overall management, but this is strongly affected by the different approaches in modeling systems where recycling occurs. As regards the impact contributions, the most impacting phases in the overall system are the bag production (for bioplastic) and the food waste collection. The analysis allowed also to state that shopper bags are less impacting than dedicated bioplastic bags because they are utilized, as the first purpose, for carrying the grocery shopping. Please click Additional Files below to see the full abstract. Please click Download on the upper right corner to see the presentation

Quality degradation in glass recycling: substitutability model proposal

: The sustainability assessment of waste management systems requires tools capable of evaluating material quality degradation during recycling. Existing research has predominantly focused on the development of substitutability models for plastics, leaving a gap in addressing other materials like glass. Glass is commonly regarded as endlessly recyclable, even though its actual recyclability depends on several crucial factors, such as colour and pollutant contamination. Many Life Cycle Assessment (LCA) studies in this field assume a one-to-one substitution coefficient, neglecting material deterioration and inaccurately representing real-world scenarios. This study proposes and assesses a substitutability model for glass, aiming to measure the replacement extent between virgin materials and recycled crushed glass (cullet). The methodology is based on two key factors: technical quality substitutability, considering impurities and colour contaminations in cullet, and market applicability, accounting for market demand. Once formulated, the model was applied to a European case study on glass waste treatment. Two scenarios were considered: one assuming complete substitution between cullet and raw materials, the other incorporating quality degradation. Findings indicate that, accounting for quality degradation, only 83% of cullet effectively replaces raw materials, resulting in a decrease of the benefit associated with recycling of 13-23% for the different examined impact categories, compared to complete replacement assumption. This underscores the importance of considering quality deterioration in glass recycling impact assessments

Integrated municipal waste management systems: An indicator to assess their environmental and economic sustainability

Tools based on Life Cycle Thinking (LCT) are routinely used to assess the environmental and economic performance of integrated municipal solid waste (MSW) management systems. Life Cycle Assessment (LCA) is used to quantify the environmental impacts, whereas Life Cycle Costing (LCC) allows financial and economic assessments. These tools require specific experience and knowledge, and a large amount of data. The aim of this project is the definition of an indicator for the assessment of the environmental and economic sustainability of integrated MSW management systems. The challenge is to define a simple but comprehensive indicator that may be calculated also by local administrators and managers of the waste system and not only by scientists or LCT experts. The proposed indicator is a composite one, constituted by three individual indicators: two of them assess the environmental sustainability of the system by quantifying the achieved material and energy recovery levels, while the third one quantifies the costs. The composite indicator allows to compare different integrated MSW management systems in an objective way, and to monitor the performance of a system over time. The calculation of the three individual indicators has been tested on the integrated MSW management systems of the Lombardia Region (Italy) as well as on four of its provinces (Milano, Bergamo, Pavia, and Mantova)

Unphysical and physical solutions in many-body theories: from weak to strong correlation

International audienceMany-body theory is largely based on self-consistent equations that are constructed in terms of the physical quantity of interest itself, for example the density. Therefore, the calculation of important properties such as total energies or photoemission spectra requires the solution of nonlinear equations that have unphysical and physical solutions. In this work we show in which circumstances one runs into an unphysical solution, and we indicate how one can overcome this problem. Moreover, we solve the puzzle of when and why the interacting Green's function does not unambiguously determine the underlying system, given in terms of its potential, or non-interacting Green's function. Our results are general since they originate from the fundamental structure of the equations. The absorption spectrum of lithium fluoride is shown as one illustration, and observations in the literature for some widely used models are explained by our approach. Our findings apply to both the weak and strong-correlation regimes. For the strong-correlation regime we show that one cannot use the expressions that are obtained from standard perturbation theory, and we suggest a different approach that is exact in the limit of strong interaction

Analisi dei metodi di integrazione degli indicatori economici e ambientali

La valutazione della sostenibilità di un processo produttivo sarebbe facilitata dalla disponibilità di strumenti in grado di rappresentarne le prestazioni economiche e quelle ambientali attraverso un unico indicatore. L’obiettivo dell’articolo è proprio quello di identificare la tecnica più indicata a valutare un sistema considerando contemporaneamente la dimensione ambientale e quella economica. In questo modo sarebbe possibile individuare, laddove necessario, qual è l’alternativa migliore tra una serie di opzioni aventi la stessa funzione. Tramite una ricerca bibliografica si sono individuati i seguenti metodi d’integrazione: i) ottimizzazione vettoriale; ii) eco-efficienza; iii) Metodi-Decisionali Multi Attributo (MDMA). I tre differiscono sia per lo scopo con cui viene condotta l’analisi che per il formato degli esiti. Pertanto, la scelta del metodo è funzione del tipo di problema che si intende risolvere. L’ottimizzazione vettoriale e l’eco-efficienza non consentono realmente di integrare le due sfere, dato che il primo le valuta in maniera indipendente e il secondo ne definisce solamente il rapporto. La sola tecnica a fornire un unico punteggio che rispecchi davvero le prestazioni complessive di un sistema è quella dei MDMA, la quale include nell’analisi anche i giudizi dei decisori tramite l’uso di coefficienti di ponderazione. La fase di definizione dei pesi dev’essere svolta con estrema cura, in quanto estremamente delicata. Solo in questo modo è possibile determinare dei coefficienti che rispecchino realmente le preferenze dei decisori oppure, secondo un discorso più generale, le politiche in atto. I giudizi espressi, tuttavia, sono spesso imprecisi, provocando un aumento dell’incertezza della valutazione. A ragion di ciò, si è scelto di analizzare un metodo in particolare, ovvero quello del FAHP&TOPSIS, il quale riduce gli effetti causati dall’uso di dati approssimativi grazie all’applicazione della teoria degli insiemi fuzzy

Estimating Excitonic Effects in the Absorption Spectra of Solids: Problems and Insight from a Guided Iteration Scheme

A major obstacle for computing optical spectra of solids is the lack of reliable approximations for capturing excitonic effects within time-dependent density-functional theory. We show that the trustful prediction of strongly bound electron-hole pairs within this framework using simple approximations is still a challenge and that available promising results have to be revisited. Deriving a set of analytical formula we analyze and explain the difficulties. We deduce an alternative approximation from an iterative scheme guided by previously available knowledge, significantly improving the description of exciton binding energies. Finally, we show how one can "read" exciton binding energies from spectra determined in the random phase approximation, without any further calculation.Comment: 5 pages, 2 figures plus supplemental materia

Life cycle costing della catena di gestione dei rifiuti da costruzione e demolizione

Il seguente lavoro si pone l’obiettivo di valutare i costi della demolizione selettiva e dell’uso degli aggregati riciclati attraverso l'applicazione della metodologia dell’Environmental Life Cycle Costing (eLCC). L'analisi eLCC ha incluso i costi preliminari, di acquisizione macchinari, operativi e di conferimento relativi all'intera catena di gestione dei rifiuti da costruzione e demolizione (C&D). Sulla base dei risultati ottenuti è stato possibile delineare alcuni scenari prevedendo meccanismi di incentivazione a beneficio della demolizione selettiva e dell’uso degli aggregati riciclati per favorire il raggiungimento di un’economia circolare nel settore delle costruzioni

Supporting a transition towards sustainable circular economy: sensitivity analysis for the interpretation of LCA for the recovery of electric and electronic waste

Purpose: The interpretation is a fundamental phase of life cycle assessment (LCA). It ensures the robustness and the reliability of the overall study. Moving towards more circular economy requires that different waste management options are systematically scrutinized to assess the environmental impacts and benefits associated to them. The present work aims at illustrating how a sensitivity analysis could be applied to the impact assessment step supporting the interpretation of a LCA study applied to a waste management system that includes material recovering. The focus is on toxicity-related and resource-related potential impacts as they are considered among the most critical ones, which may affect the way the final benefit from material recovery is evaluated. Methods: Possible alternatives in terms of impact assessment assumptions and modelling are tested by performing a sensitivity analysis on a case study on electric and electronic waste. For the toxicity-related impact categories, first, a sensitivity analysis is performed using different sets of characterization factors for metals aiming at identifying how they are affecting the final results. Then, an analysis of the relative contribution of long-term emissions in upstream processes is carried out aiming at unveiling critical issues associated to their inclusion or exclusion. For the resource depletion impact category, a sensitivity analysis has been performed, adopting different sets of characterization factors based on existing models for minerals and metals as well as recently proposed sets accounting for critical raw materials. Results and discussion: The indicator of the ecotoxicity impact category obtained by applying the updated characterization factors is about three times higher than the corresponding obtained by the USEtox model. The long-term emission result is responsible for the major part of all the toxicity impact indicators. Moreover, for the ecotoxicity indicator, excluding the long-term emissions changes the total results from being negative into positive. The sensitivity analysis for the resource depletion impact category shows that all the models applied result in a total avoided impact. A quantitative comparison among all the results is not possible as the different models use different units of measure. Conclusions: The application of LCA is crucial for assessing avoided impacts and uncovers potential impacts due to recycling. However, contrasting results may stem from the application of different assumptions and models for characterization. A robust interpretation of the results should be based on systematic assessment of the differences highlighted by the sensitivity, as guidance for delving into further analysis of the drivers of impacts and/or to steer ecoinnovation to reduce those impacts