Limitations of applying life cycle assessment to complex co-product systems: The case of an integrated precious metals smelter-refinery

Integrated smelter-refineries play an important role in the recovery of multiple metals from complex primary and secondary materials, and hence in closing metals cycles. Processes in these facilities are strongly interconnected, dynamic, and multifunctional, which challenges a typical representation in life cycle assessment (LCA). This is especially true when LCA is applied to calculate the environmental profile of single metals products.This study examines methodological requirements for assessing complex co-product systems using attributional LCA through a static, gate-to-gate inventory model that quantifies the environmental impacts of each of the metal products of an integrated precious metals smelter-refinery. The model is based on a large number of subprocesses and is formulated using detailed industry data, which allows quantification of the sensitivity of the results with respect to allocation rationales and the data collection period.The results within one impact category vary strongly among metals (up to four orders of magnitude for copper compared to rhodium). Moving from mass- to value-based allocation changes the result for a given metal by up to two orders of magnitude. If value-based allocation is used, the selected reference year for metals prices influences the results by up to a factor of two.Allocation rationales are critically analyzed, and it is shown that none reflect the business model or other system drivers. While the model is focused on quantifying environmental impacts of metal outputs, the actual process is economically driven to efficiently treat a continuously changing feed mix. The complexity of a smelter-refinery cannot be captured by static, attributional inventory models, which is why the choice of allocation rationale remains arbitrary. Instead, marginal, parameterized models are needed; however, such models are substantially more time and data intensive and require disclosure of more detailed, process specific data.     

Life cycle assessment of Italian citrus-based products. Sensitivity analysis and improvement scenarios

Though many studies concern the agro-food sector in the EU and Italy, and its environmental impacts, literature is quite lacking in works regarding LCA application on citrus products. This paper represents one of the first studies on the environmental impacts of citrus products in order to suggest feasible strategies and actions to improve their environmental performance. In particular, it is part of a research aimed to estimate environmental burdens associated with the production of the following citrus-based products: essential oil, natural juice and concentrated juice from oranges and lemons. The life cycle assessment of these products, published in a previous paper, had highlighted significant environmental issues in terms of energy consumption, associated CO₂ emissions, and water consumption. Starting from such results the authors carry out an improvement analysis of the assessed production system, whereby sustainable scenarios for saving water and energy are proposed to reduce environmental burdens of the examined production system. In addition, a sensitivity analysis to estimate the effects of the chosen methods will be performed, giving data on the outcome of the study. Uncertainty related to allocation methods, secondary data sources, and initial assumptions on cultivation, transport modes, and waste management is analysed. The results of the performed analyses allow stating that every assessed eco-profile is differently influenced by the uncertainty study. Different assumptions on initial data and methods showed very sensible variations in the energy and environmental performances of the final products. Besides, the results show energy and environmental benefits that clearly state the improvement of the products eco-profile, by reusing purified water use for irrigation, using the railway mode for the delivery of final products, when possible, and adopting efficient technologies, as the mechanical vapour recompression, in the pasteurisation and concentration of juice.     

From the LCA of food products to the environmental assessment of protected crops districts: a case-study in the south of Italy

In the present study, Life Cycle Assessment (LCA) methodology was applied to evaluate the energy consumption and environmental burdens associated with the production of protected crops in an agricultural district in the Mediterranean region. In this study, LCA was used as a 'support tool', to address local policies for sustainable production and consumption patterns, and to create a 'knowledge base' for environmental assessment of an extended agricultural production area. The proposed approach combines organisation-specific tools, such as Environmental Management Systems and Environmental Product Declarations, with the environmental management of the district. Questionnaires were distributed to producers to determine the life cycle of different protected crops (tomatoes, cherry tomatoes, peppers, melons and zucchinis), and obtain information on greenhouse usage (e.g. tunnel vs. pavilion). Ecoprofiles of products in the district were also estimated, to identify supply chain elements with the highest impact in terms of global energy requirements, greenhouse gas emissions, eutrophication, water consumption and waste production. These results of this study enable selection of the 'best practices' and ecodesign solutions, to reduce the environmental impact of these products. Finally, sensitivity analysis of key LCA issues was performed, to assess the variability associated with different parameters: vegetable production; water usage; fertiliser and pesticide usage; shared greenhouse use; substitution of plastics coverings; and waste recycling.     

Use of recycled natural fibres in industrial products: A comparative LCA case study on acoustic components in the Brazilian automotive sector

This paper summarizes the results and the lessons learnt from an LCA case study comparing acoustic automotive components. Three alternative acoustic components produced by the Brazilian automotive sector are considered: dual-layer polyurethane (DL-PU) panel, recycled textile absorption-barrier-absorption (ABA-cotton) panel and recycled textile DL (DL-cotton) panel. DL-PU is a “status-quo” alternative, composed mainly of synthetic plastics and the two other alternatives are mainly made of recycled cotton fibres. Using the Life Cycle Assessment (LCA) method, the three following phases of the panels’ life cycle are examined: production, use and end-of-life. For the latter, two end-of-life scenarios are analysed: landfill and incineration with energy recovery. For the LCA model, some Life Cycle Inventory (LCI) datasets have been adapted from the data available in the EcoInvent database in order to adjust to the Brazilian context. LCA results show that, within the entire life cycle, the DL-cotton option, which combines two layers of recycled fibres of different densities, is overall the best alternative from an environmental perspective. This result is therefore independent from the end-of-life scenario. This is mainly due to the lower weight of this component, which is extremely important for the transportation aspects, but also due to its lower consumption of fossil resources, to the energy saving during its production and to the avoidance of textile disposal that would happen otherwise. The obtained results confirm the available literature dealing with the use of renewable fibres in industrial products. The particular behaviour of recycled fibres compared to virgin ones (in terms of shared contribution of agricultural production and of avoidance of landfilling) is highlighted in this paper, thanks to the application of the “50/50” allocation rule. LCA results are discussed in terms of their potential use in an R&D context. Further research needs are also derived from the case study, including the potential benefits of developing multi-objective optimization methods that include environmental impact to be used in the design of such a component.     

The joint use of LCA and emergy evaluation for the analysis of two Italian wine farms

The aim of this paper is to evaluate two agroindustrial productive processes in their entirety (one organic and one semi-industrial), focusing on the comparison of impacts derived from the inputs and outputs of the system (life cycle assessment, LCA), integrated with a physical evaluation of the resources and natural services, on a common basis (emergy). Methods based on the joint use of LCA and emergy evaluation are useful, as they measure the contribution of environmental services and products to the productive process thus focusing primarily on the environmental impact of emissions and non-renewable energy inputs. The complementarity of the methods used in this paper contributes important elements and information useful for the comprehension of the organization of agriculture within Siena's territory. The results show important elements and useful information: (1) for the comprehension of the two agroecosystems' organization; (2) for the use of the energy flows that determine their development. Moreover, the combined use of emergy and LCA gives a comparative thermodynamic performance evaluation between organic and semi-industrial farming.     

An analysis of the use of life cycle assessment for waste co-incineration in cement kilns

Life cycle assessment, LCA, has become a key methodology to evaluate the environmental performance of products, services and processes and it is considered a powerful tool for decision makers. Waste treatment options are frequently evaluated using LCA methodologies in order to determine the option with the lowest environmental impact. Due to the approximate nature of LCA, where results are highly influenced by the assumptions made in the definition of the system, this methodology has certain non-negligible limitations. Because of that, the use of LCA to assess waste co-incineration in cement kilns is reviewed in this paper, with a special attention to those key inventory results highly dependent on the initial assumptions made. Therefore, the main focus of this paper is the life cycle inventory, LCI, of carbon emissions, primary energy and air emissions. When the focus is made on cement production, a tonne of cement is usually the functional unit. In this case, waste co-incineration has a non-significant role on CO₂ emissions from the cement kiln and an important energy efficiency loss can be deduced from the industry performance data, which is rarely taken into account by LCA practitioners. If cement kilns are considered as another waste treatment option, the functional unit is usually 1 t of waste to be treated. In this case, it has been observed that contradictory results may arise depending on the initial assumptions, generating high uncertainty in the results. Air emissions, as heavy metals, are quite relevant when assessing waste co-incineration, as the amount of pollutants in the input are increased. Constant transfer factors are mainly used for heavy metals, but it may not be the correct approach for mercury emissions.     

Methodological aspects of life cycle assessment of integrated solid waste management systems

Environmental life cycle assessment (LCA) developed rapidly during the 1990s and has reached a certain level of harmonisation and standardisation. LCA has mainly been developed for analysing material products, but can also be applied to services, e.g. treatment of a particular amount of solid waste. This paper discusses some methodological issues which come into focus when LCAs are applied to solid waste management systems. The following five issues are discussed. (1) Upstream and downstream system boundaries: where is the ‘cradle’ and where is the ‘grave’ in the analysed system? (2) Open-loop recycling allocation: besides taking care of a certain amount of solid waste, many treatment processes also provide additional functions, e.g. energy or materials which are recycled into other products. Two important questions which arise are if an allocation between the different functions should be made (and if so how), or if system boundaries should be expanded to include several functions. (3) Multi-input allocation: in waste treatment processes, different materials and products are usually mixed. In many applications there is a need to allocate environmental interventions from the treatment processes to the different input materials. The question is how this should be done. (4) Time: emissions from landfills will continue for a long time. An important issue to resolve is the length of time emissions from the landfill should be considered. (5) Life cycle impact assessment: are there any aspects of solid waste systems (e.g. the time horizon) that may require specific attention for the impact assessment element of an LCA? Although the discussion centres around LCA it is expected that many of these issues are also relevant for other types of systems analyses.     

Using LCA to evaluate impacts and resources conservation potential of composting: A case study of the Asti District in Italy

Separate collection of municipal solid waste has overcome the 50% threshold in the Asti District in northern Italy, nearly one-third being composed of household and green organic waste. In order to address present and future solutions, it becomes therefore fundamental to assess the environmental performances of the current management of organic waste from separate collection. A from-gate-to-cradle life cycle assessment (LCA) model has been developed by expanding system boundaries, in order to carry out the assessment in the context of the whole waste management streamline. The environmental performances of an existing aerobic plant were made available, based on field measured data, by paying attention to the role and contribution of waste management subsystems. The need for actual and reliable data on materials and energy input, as well as gross and net gains from materials recovery, including benefits arising from use of compost in farming activities, was probably the major drawback that had to be faced. The study integrated the findings of different investigations from the literature with field measured data in order to obtain a more comprehensive framework representative of the area under study. The results may help public administrators to better understand the suitability of using LCA tools when dealing with solid waste management strategies.     

Using LCA to evaluate impacts and resources conservation potential of composting: A case study of the Asti District in Italy

Separate collection of municipal solid waste has overcome the 50% threshold in the Asti District in northern Italy, nearly one-third being composed of household and green organic waste. In order to address present and future solutions, it becomes therefore fundamental to assess the environmental performances of the current management of organic waste from separate collection. A from-gate-to-cradle life cycle assessment (LCA) model has been developed by expanding system boundaries, in order to carry out the assessment in the context of the whole waste management streamline. The environmental performances of an existing aerobic plant were made available, based on field measured data, by paying attention to the role and contribution of waste management subsystems. The need for actual and reliable data on materials and energy input, as well as gross and net gains from materials recovery, including benefits arising from use of compost in farming activities, was probably the major drawback that had to be faced. The study integrated the findings of different investigations from the literature with field measured data in order to obtain a more comprehensive framework representative of the area under study. The results may help public administrators to better understand the suitability of using LCA tools when dealing with solid waste management strategies.     

Practical life cycle assessment through streamlining

Life cycle assessment (LCA) provides a concept, framework, and method to identify and evaluate the environmental burdens of products and processes. An ongoing concern of companies trying to implement LCA is the value of LCA in supporting actual decisions versus the resources and time needed to conduct a “full” LCA. In response to these concerns, there has been a lot of activity surrounding the “streamlining” of LCA to keep it more manageable yet provide useful and acceptably accurate results. This article explores the concept of streamlining, discusses where and how streamlining decisions can be made in an LCA, and presents issues related to conducting more streamlined LCAs. Due to the wide variety of purposes and scenarios in which LCAs are conducted, it is difficult to devise a one-size-fits-all method for streamlining. Instead, we have focused on presenting the streamlining options in the context of major decision points that are common to most LCAs.     

Critical aspects in the life cycle assessment (LCA) of bio-based materials – Reviewing methodologies and deriving recommendations

Concerns over non-renewable fossil fuel supply and climate change have been driving the Renaissance of bio-based materials. To substantiate environmental claims, the impacts of bio-based materials are typically quantified by applying life cycle assessment (LCA). The internationally agreed LCA standards provide generic recommendations on how to evaluate the environmental impacts of products and services but do not address details that are specifically relevant for the life cycles of bio-based materials. Here, we provide an overview of key issues and methodologies explicitly pertinent to the LCA of bio-based materials. We argue that the treatment of biogenic carbon storage is critical for quantifying the greenhouse gas emissions of bio-based materials in comparison with petrochemical materials. We acknowledge that biogenic carbon storage remains controversial but recommend accounting for it, depending on product-specific life cycles and the likely time duration of carbon storage. If carbon storage is considered, co-product allocation is nontrivial and should be chosen with care in order to: (i) ensure that carbon storage is assigned to the main product and the co-product(s) in the intended manner and (ii) avoid double counting of stored carbon in the main product and once more in the co-product(s). Land-use change, soil degradation, water use, and impacts on soil carbon stocks and biodiversity are important aspects that have recently received attention. We explain various approaches to account for these and conclude that substantial methodological progress is necessary, which is however hampered by the complex and often case- and site-specific nature of impacts. With the exception of soil degradation, we recommend preliminary approaches for including these impacts in the LCA of bio-based materials. The use of attributional versus consequential LCA approaches is particularly relevant in the context of bio-based materials. We conclude that it is more challenging to prepare accurate consequential LCA studies, especially because these should account for future developments and secondary impacts around bio-based materials which are often difficult to anticipate and quantify. Although hampered by complexity and limited data availability, the application of the proposed approaches to the extent possible would allow obtaining a more comprehensive insight into the environmental impacts of the production, use, and disposal of bio-based materials.     

POEMS: A Case Study of an Italian Wine-Producing Firm

Over the last decade, researchers paid much attention to concepts such as Design for Environment, Extended Producer Responsibility, Responsible Chain Management, and Eco-design. Many management tools and standards (such as EMAS, ISO 14001, LCA, EPD, Ecolabel) have been developed to support companies in the evaluation and management of their environmental performance and to pursue continual environmental improvement. The more recent development of the aforesaid fields looks at interorganizational environmental management. Such an approach can complement the more traditional intraorganizational corporate environmental management approaches and tools. A typical example of this new trend is the Product Oriented Environmental Management System (POEMS), which represents the natural evolution of the above-mentioned tools, combining the features of EMS, EPD and Ecolabel. Although the structure of the POEMS is still not standardized, many experimental applications have yet been carried out in Europe. In developing a POEMS, a company needs to determine all of the environmental impacts caused at all life-cycle stages of the product and, ideally, to reduce all of them through a continual commitment. The aim of the present study was to perform a survey of the developed POEMS models and to analyze their peculiarities and drawbacks in the application to Small and Medium Enterprises. A case study regarding an Italian winery company is presented. The study analyzes the structure and the activities of the examined firm, in order to estimate direct and indirect environmental impacts following a life-cycle approach. The chosen functional unit is a 0.75-L bottle of red wine. The article also suggests some solutions to improve the environmental performances of the firm’s products.     

后石油时代沙生灌木直燃发电对环境的影响＊

文章通过对内蒙古中西部地区沙生灌木的成分分析,基于生命周期法(LCA),定量论证了沙生灌木直燃发电开发模式对环境的影响和推广的可行性,指出相比石油等传统能源,这种模式具有较大的潜在效益,对于我国发展绿色替代能源,促进西部地区生态环境和经济协调发展具有一定的战略意义。     

Methodological advancements in Life Cycle Process Design: A preliminary outlook

This paper deals with the application of Life Cycle Assessment (LCA) methodology for process design, and presents the initial findings of this analysis qualitatively. The work identifies a need for a methodological development of Life Cycle Process Design (LCPD). This is underpinned by a broad literature review. The literature review shows that the application of LCA as an environmental design instrument is recognized in literature. In contrast to that there is hardly any hint which role Life Cycle Costing (LCC) could play within environmental process design. Most interesting in this line is, how LCA and LCC can be combined for environmental process design to be finally the core instruments of LCPD. The applicability of LCA and LCC within LCPD is shown on the example of a novel biorefinery process under development. Both instruments (LCA and LCC) are already applied during basic process development in this work, parallel to laboratory research. The aim is to identify potential environmental threats at an early stage of process design and also to give a hint on economic feasibility. Additionally a trade-off between environmental and economic issues can be drawn out. On the basis of this analysis the role of LCA during process development is highlighted as well as difficulties and challenges are emphasized. One of the major obstacles is data availability for LCA as well as LCC in the basic design stage of a biotechnological process. The findings of this paper serve as basis for the methodological development of LCPD. It is emphasized that conducting LCA and LCC during basic process development can reveal some relevant action areas for process engineers, which may influence technical as well as economic feasibility. The results presented have to be understood as a first outlook and provide key aspects for future research on the topic of accompanying basic process research projects with LCA and LCC to support future sustainable process design.     

Assessing relationships among life-cycle environmental impacts with dimension reduction techniques

Nowadays, there is a trend in many countries towards more environmentally benign products and processes. Life-Cycle Assessment (LCA) is a quantitative analysis tool developed and utilized for the evaluation of environmental impacts occurring throughout the entire life-cycle of a product, process or activity. LCA requires a large amount of data in its different phases and can also generate large amounts of results which may be hard to interpret. In order to uncover and visualize the structure of large multidimensional data sets, Multivariate Analysis techniques can help. Hence, in this paper, a methodology using Principal Component Analysis and Multi-Dimensional Scaling is proposed and illustrated by means of two case studies. The first case study evaluates the operation of several wastewater treatment plants. The second case study deals with the environmental evaluation of the cultivation, processing and consumption of mussels. In both case studies, the redundancy present in the data allowed a dimensionality reduction from seven and ten to two dimensions, with a small loss of information. Plotting the environmental impact data in these two dimensions can help visualize, interpret and communicate them.     

On process optimization considering LCA methodology

The goal of this work is to research the state-of-the-art in process optimization techniques and tools based on LCA, focused in the process engineering field. A collection of methods, approaches, applications, specific software packages, and insights regarding experiences and progress made in applying the LCA methodology coupled to optimization frameworks is provided, and general trends are identified. The "cradle-to-gate" concept to define the system boundaries is the most used approach in practice, instead of the "cradle-to-grave" approach. Normally, the relationship between inventory data and impact category indicators is linearly expressed by the characterization factors; then, synergic effects of the contaminants are neglected. Among the LCIA methods, the eco-indicator 99, which is based on the endpoint category and the panel method, is the most used in practice. A single environmental impact function, resulting from the aggregation of environmental impacts, is formulated as the environmental objective in most analyzed cases. SimaPro is the most used software for LCA applications in literature analyzed. The multi-objective optimization is the most used approach for dealing with this kind of problems, where the ε-constraint method for generating the Pareto set is the most applied technique. However, a renewed interest in formulating a single economic objective function in optimization frameworks can be observed, favored by the development of life cycle cost software and progress made in assessing costs of environmental externalities. Finally, a trend to deal with multi-period scenarios into integrated LCA-optimization frameworks can be distinguished providing more accurate results upon data availability.     

Introducing design for the environment at boeing defense and space group through the application of abridged life-cycle analysis

The streamlined, matrix approach to environmental Life-Cycle Analysis (LCA) developed originally at AT&T by Graedel and Allenby can be adapted to manufacturing processes to produce a useful tool for Design for the Environment (DFE). Pollution prevention in manufacturing has typically focused on the environmental impact of processes at a manufacturer's site. However, it is important to recognize that a process has a “life cycle,” albeit not precisely like the life cycle associated with a product. Modification of processes can also have upstream and downstream effects. In this article, the authors show how, by using a streamlined LCA matrix, it is possible to evaluate the environmental impact associated with a process over the process's life cycle. This approach also allows managers to allocate resources to improve processes that have greater environmental impact and to assess process improvements.     

A Multi-Years Analysis of the Energy Balance,Green Gas Emissions,and Production Costs of First and Second Generation Bioethanol

Contemporary reports on the energy and environmental benefits of bioethanol have suggested that the cellulosic ethanol is significantly more efficient. To understand the development potential of energy crops in Taiwan, the present study has assessed the resources and cost inputs for the planning, harvesting, transporting, and storing procedures of the first generation energy crops during 2007–2010 with the perspective of LCA. In addition, a field investigation focusing on rice straw, the largest agricultural waste in Taiwan, has been conducted since 2010 to obtain fundamental data.This study further analyzes the first and second-generation feedstocks from the perspective of LCA based on field investigated data. Taiwan has not yet established an ethanol plant; therefore, this study established production data by simulating the production efficiency of an economical scale using parameters obtained through production trials, and proposed an evaluation model for the energy input, GHG, and production costs of bioethanol in Taiwan. The results of this study were cross-compared with foreign literature to explore the development potential of bioethanol in Taiwan. The results indicate that based on the current cellulosic ethanol technology in Taiwan, regarding the energy balance, GHG, and production costs, is less efficient than that of the first generation bioethanol.