Scrapping steel components for recycling—Isn’t that good enough? Seeking improvements in automotive component end-of-life

Life cycle management (LCM) suggests that companies take responsibility for the entire lifecycle of their products, either alone or together with other lifecycle actors. This paper examines the case of an automotive component manufacturer that has committed to LCM and wants to investigate product end of life (EoL) management despite the fact that it is a couple stages removed from the vehicle end-user and EoL vehicle (ELV) handling. Material flow analysis (MFA) is used to estimate and create Sankey diagrams of the downstream flows of two components made of low-alloyed steel, one wheel component and one gearbox component. Product sales data was analyzed and composition and design trends were considered to add perspectives beyond those yielded by looking at the bulk material flow. The components of interest are not remanufactured themselves but the gearboxes in which they sit are. Remanufacturers of gearboxes visited indicated a great variability in how much they replace the components of interest suggesting an opportunity for the case company to support remanufacturers in quality control and extension of use life. In regards to component EoL, many components are sent through shredding as part of ELV treatment but a comparable amount is liberated from vehicles and scrapped during vehicle maintenance. Regardless, the components end up in mixed scrap and alloying elements are rarely functionally recycled. According to commodity experts, an alternative to handle such components separately for functional recycling is practically limited. Component quantities and their values do not appear to justify additional administration and transport that would be require to sort, store and collect them. Accordingly, when considering societal interest to increase functional recycling and to activate the circular economy, it seems warranted to investigate what a recycling program for similar material grades could yield and subsequently, to consider what collaborative efforts or policy intervention would be relevant

Simulating operational alternatives for future cement production

To support decisions on product and process development options and strategic planning, information on the consequences of planned changes are needed. For this purpose a flexible model for cement manufacturing has been developed. The model predicts the environmental, product and economic performance in a life cycle perspective, simulating different operational alternatives. Interesting future operational alternatives, such as an increase in the use of industrial by-products and wastes as raw materials and fuels have been explored. The results, i.e. the consequences from a life cycle perspective of potential development options, are discussed. The nine simulations show that the use of recovered material and alternative fuel (defined waste) can be increased while maintaining the current requirements on clinker performance. An increase in the use of recovered material and alternative fuel replaces the use of resources. The simulations also show that the emissions of CO 2 , NO X , SO 2 , CO, VOC, CH 4 and dust can be reduced between 30 and 80% depending on the use of recovered material and alternative fuel. The transport of recovered material and alternative fuel increases with increased use. However, the environmental benefits of the increase in use of recovered material and alternative fuel are by far greater than the resource use and emissions to air associated with the increase in transport. \ua9 2005 Published by Elsevier Ltd

Actors and interpretations in an environmental controversy: the Swedish debate on sewage sludge use in agriculture

This study examines the Swedish debate on the sustainability of using sewage sludge as fertiliser in agriculture. Although the use of sludge as fertiliser presents potential resource and environmental advantages, it can have negative effects on people and soil productivity. Both proponents and opponents of agricultural application of sludge use environmental arguments to support their positions. By 1990, the Swedish parliament stressed the importance of recycling nutrients from wastewater; however, despite low levels of contamination, compared to other countries, little sludge is used in agriculture today. During the last few decades, a large amount of research has addressed the risks and benefits of using sludge as fertiliser, but the central actors have not been able to reach lasting agreements. This study, which is based on document analysis, direct observations, and interviews, analyses the beliefs, preferences, and arguments of major actors in the national debate on sludge. The study investigates how actors define problems and interpret the risks and benefits of sludge use. Specifically, the study concentrates on the role of science in the sludge controversy. Two distinct ways of thinking - a precautionary frame and a proof-first frame - are identified. These frames are shown almost immune to factual claims and arguments from opponents. It is concluded that actors in the controversy need to address explicitly value judgements and beliefs that go beyond scientific information. In addition, the study concludes that there is a need for policy makers to further develop process leadership skills. \ua9 2004 Elsevier B.V. All rights reserved

Comparative life cycle assessment of polyethylene based on sugarcane and crude oil

The goal of this study was to assess the environmental performance of low density polyethylene (LDPE) based on Brazilian sugarcane ethanol and compare it to LDPE based on crude oil and to answer the question if it is environmentally preferable in the production of goods and packaging in Europe. The production routes were compared in a life cycle perspective.The investigated life cycles start with the cultivation of sugarcane in Brazil and extraction of crude oil in the Middle East, followed by the production of LDPE in Brazil and Europe, respectively. The LDPE was assumed to be used in Europe for both alternatives. A generic waste treatment scenario was applied, incineration, with recovery of the released heat to electricity. The assessment method used was life cycle assessment (LCA) in its two methodological approaches – consequential and attributional LCA. The two approaches were consistently applied in parallel to investigate the impact of methodological choices on the outcome of the LCA.Use of fossil fuels and release of greenhouse gases were considered to be the two most important types of environmental impact in the study. As may be expected, the use of fossil fuels proved to be much lower for the sugarcane based LDPE. The results for global warming show that, if effects of land use change are disregarded, the sugar cane route comes out much better than the oil based route. However, there are greenhouse gases released as a consequence of the rapid land use changes taking place in Brazil. It has not been possible to quantify the extent of these emissions with any degree of certainty, but the available data indicate that the effects of land use changes may be significant. The emissions may even be in the order of magnitude to flip the ranking between the oil based and the sugarcane based route to LDPE. But again, the data are too uncertain to allow for any ranking of the alternatives with respect to global warming potential. What may be said though is that if the feed-stock were to come from some type of biomass that does not imply land use changes, LDPE based on ethanol is probably an environmentally much better alternative than LDPE based on oil. In summary, polyethylene based on ethanol uses significantly less fossil fuels than the oil based alternative, and has the potential to significantly reduce emissions of greenhouse gases. However, as long as the ethanol is based on sugarcane, the cultivation of which leads to land use changes, there is considerable risk that the positive effect on greenhouse gas emissions is overturned by emissions resulting from land use changes. The dominance and sensitivity analyses showed that the surrounding technical systems, such as electricity production system and waste management system have a large influence on the results. This was most clearly demonstrated by placing the oil-based route in a Swedish context (oil from North Sea, Swedish electricity production mix). The effect was a dramatically reduced environmental impact, particularly in terms of acidification, eutrophication and photochemical oxidant formation. Shorter transport distances also drastically reduced acidification, and to a lesser extent eutrophication and formation of photooxidants. The project has revealed extensive knowledge gaps regarding environmental impacts resulting from land use change. Research is needed not only to generate data on the size of the emissions, but also into methodology on how to use such data in LCA

A life cycle based method to minimise environmental impact of dairy production through product sequencing

The trend of increasing the number of dairy products for sale affects their environmental impact in a life cycle perspective. During dairy processing, the production schedule is affected by more frequent product changes, hence also cleaning operations. This causes more milk waste, use of cleaning agents and water. The amount of milk waste depends on the product change technique used, which is determined by the characteristics of the product. A method was designed to calculate the sequence, which, for a given set of yoghurt products, minimises milk waste. A heuristic method, based on the strive to minimise production waste combined with production rules, was worked out. To determine whether the heuristic solution gives the best possible sequence from an environmental perspective, an optimisation was also made. The analytical method used for optimisation was able to handle 21 products and verified the heuristic method for a waste minimised sequence up to that level. It is also highly probable that for sequences including a greater number of items waste can be minimised with the same heuristic method. A successful demonstration of the possibility to make a more complete environmental assessment was fulfilled by connecting the sequencing model to conventional life cycle assessment methodology

Life cycle assessment of biomass-based ethylene production in Sweden - is gasification or fermentation the environmentally preferable route?

Purpose To reduce its environmental impact, the chemical industry is investigating the biomass-based production of chemicals such as ethylene, including fermentation and gasification conversion processes. However, a comprehensive study that compares the environmental impact of these biomass routes is missing. This study assesses and compares a wood gasification with a wood fermentation route to ethylene in Sweden, as well as compares it with the commercialized sugarcane and fossil oil alternatives. Methods The study followed the methodology of life cycle assessment. A cradle-to-gate perspective for the production of 50,000 t ethylene/year was applied, and the following impact categories were investigated: global warming (GWP), acidification (ACP), photochemical ozone creation (POCP), and eutrophication (EP). Results and discussion Biomass acquisition including transport to the gasification plant was the major cause of the gasification route’s GWP and POCP, suggesting improvements with regard to fuel source and machine efficiency. NOx emissions from the gasification process had the main share on the ACP and EP. The comparison of the gasification with a wood and a sugarcane fermentation route showed a lower impact for the gasification route. Among other things, this is caused by high emissions from transport and cultivation for the sugarcane route and high emissions from enzyme and ethanol production for the wood fermentation route. The results were less distinct for a comparison of the gasification with a fossil-based route. Fossil-based ethylene production was found to be preferable for the ACP and the EP, but less preferable for the GWP and POCP. However, it needs to be considered that the fossil route has been optimized for decades and is still ahead of the gasification and other biomass routes. Conclusions The study shows that a gasification-based production of ethylene could outperform a fermentation-based one; however, further investigations are recommended, given the state of development of the investigated biomass routes. Moreover, based on the limited availability of biomass, further investigations into economical and ecological restrictions are of importance

Life Cycle Assessment of Municipal Waste Water Systems

Life Cycle Assessment was applied to municipal planning in a study of waste water systems in Bergsjön, a Göteborg suburb, and Hamburgsund, a coastal village. Existing waste water treatment consists of mechanical, biological and chemical treatment. The heat in the waste water from Bergsjön is recovered for the district heating system. One alternative studied encompassed pretreatment, anaerobic digestion or drying of the solid fraction and treatment of the liquid fraction in sand filter beds. In another alternative, urine, faeces and grey water would separately be conducted out of the buildings. The urine would be used as fertilizer, whereas faeces would be digested or dried, before used in agriculture. The grey water would be treated in filter beds. Changes in the waste water system would affect surrounding technical systems (drinking water production, district heating and fertilizer production). This was approached through system enlargement. For Hamburgsund, both alternatives showed lower environmental impact than the existing system, and the urine separation system the lowest. Bergsjön results were more difficult to interpret. Energy consumption was lowest for the existing system, whereas air emissions were lower for the alternatives. Water emissions increased for some parameters and decreased for others. Phosphorous recovery was high for all three alternatives, whereas there was virtually no nitrogen recovery until urine separation was introduced

Normative ethics and methodology for life cycle assessment

Prospective life cycle assessment (LCA) provides information on the environmental consequences of individual actions. Retrospective LCA provides information about the environmental properties of the life cycle investigated and of its subsystems. In this paper we analyse the links between the choice of methodology and different theories of normative moral philosophy. The choice of electricity data in an LCA of a conference site with local hydropower production is discussed as an illustration. The two types of LCA can be related to different theories on the characteristics of a good action. Each type of LCA, as well as each of the moral theories, can be criticised from the alternative point of departure. Decisions based on retrospective LCA can have environmentally undesirable consequences. On the other hand, prospective LCA can appear unfair and result in environmentally sub-optimised systems. Both types of LCA also have methodological limitations. We cannot conclude that one type is superior to the other, but the choice of methodology should be consistent with the information sought in the LCA

The design and building of a lifecycle-based process model for simulating environmental performance, product performance and cost in cement manufacturing

State of the art lifecycle inventory (LCI) models are typically used to relate resource use and emissions to manufacturing and use of a certain product. Corresponding software tools are generally specialised to perform normalisation of the flows to the functional unit. In some cases it is, however, desirable to make use of the LCI model for other types of environmental assessments. In this paper, an alternative modelling technique resulting in a more flexible model is investigated. We exemplify the above by designing and building a model of a cement plant. The commissioner\u27s, in this case Cementa AB\u27s, requirements on a flexible model that generates information on environmental performance, product performance and the economic cost were seen as important. The work reported here, thus, has two purposes: on the one hand, to explore the possibility of building more flexible LCI models, and on the other hand, to provide the commissioner with a model that fulfils their needs and requirements. Making use of a calculational a-causal and object-oriented modelling approach satisfied the commissioner\u27s special requirements on flexibility in terms of modularity and the types of calculations it was possible to perform. In addition, this model supports non-linear and dynamic elements for future use. The result is a model that can be used for a number of purposes, such as assessment of cement quality and environmental performance of the process using alternative fuels. It is also shown that by using the above modelling approach, flexibility and modularity can be greatly enhanced. \ua9 2003 Elsevier Science Ltd. All rights reserved

Prospective life cycle assessment of adipic acid production from forest residue

Moving from a fossil-based to a bio-based economy requires the development of novel technologies for the production of bio-based chemicals and materials, and the Swedish forestry sector may play a major role in this. These technologies may become part of novel biorefinery concepts that combine the production of bulk and fine chemicals. This paper presents the life cycle assessment (LCA) of such a technology, in its early stages of development, which targets the biochemical production of adipic acid from Swedish forest residue. Adipic acid is a bulk chemical and its yearly production is approximately 2.3 million tonnes. It is mainly used as a precursor in the production of nylon, and its current fossil-based production process emits significant quantities of nitrous oxide (N2O), a strong greenhouse gas. Preliminary calculations showed that, compared to conventional adipic acid production, eliminating the emission of N2O would lead to a reduction of GWP by 75%, and that switching from a fossil-based to a biomass-based feedstock would reduce GWP by an additional 10%. This LCA focused on the technology for producing adipic acid, but also considered its connection with other technologies in the biorefinery concept. An anaerobic digestion process is used to produce biogas from the waste water. As well, lignin is produced as a by-product. The heat from biogas and lignin incineration can be used to meet the energy demands of the adipic acid production. Lab-scale experimental results were used in the assessment, and scaling up these results to an industrially relevant process capacity was done by using process modelling and simulation. Furthermore, an assessment was done of the impact of extracting forest residue from the Swedish forest. The results of this LCA show that the environmental impacts of producing adipic acid from forest residues, except for acidification potential, are significantly lower than those of its conventional production. The environmental hotspot of the technology is the downstream processing stage due to its need of additional energy which was assumed to be fossil. This additional energy is needed because of the low concentration of adipic acid in the fermentation broth. Further improvements can thus be made by minimizing fossil energy use in this stage, or by aiming for a higher end concentration of adipic acid in the fermentation broth. Lastly, the extraction of forest residue was found to only marginally contribute to global warming