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Abstract Despite general agreement on the importance of adjusting each life cycle assessment (LCA) to its goal, the methodological choices in previously published LCAs on wastewater and sludge management systems are surprisingly similar, even when the information sought in the studies most likely differ. We argue that the potential of LCA may not currently be fully utilised, partly due to particular methodological challenges arising in both attributional and consequential LCAs for this type of systems. By developing the theory for handling of allocation problems in attributional LCAs, and by elaborating on the different possible foreseeable consequences in consequential LCA, we aim to facilitate both attributional and consequential LCAs, and to show the importance of such choices for a specific wastewater and sludge management system. We introduce and apply a distinction between physically and legally joint processes as basis for the allocation of resource use and emissions in attributional LCA, and suggest that, when the joint process is not driven by commercial interests, allocation factors could be identified and quantified through stakeholder priorities. In consequential LCAs, the substitution depends on the subjective view on what consequences are foreseeable, for example based on short- or long-term considerations. All of these modelling aspects can, as our case study illustrates, affect the LCA results. Highlights • An LCA should ideally be consistently attributional or consequential. • Such methodological consistency is possible in LCAs of sludge management systems. • The functions of a process can be legally joint. • Stakeholder priorities can be used as a basis for allocation. • Foreseeable consequences can be short-term or long-term. [ABSTRACT FROM AUTHOR]

Abstract In education for sustainable development (ESD), the inclusion and handling of a multitude of perspectives and the interconnectivity of different dimensions of the world are often targeted. Based on the assumption that concept maps can capture notions of this learning, concept maps generated by students were used to complement a large number of other empirical data from several years of a master level course module in engineering education with a specific focus on ESD. Multivariate data analysis (MVDA) was used to find correlations between the many different variables. Empirical data included data on the background of students, on their participation in different teaching and learning activities (TLAs), and on their performance in different types of assessment, including concept maps generated before and after the course. According to the concept map results, the students seem to develop, in general, a more balanced and systemic view during the course. The use of MVDA was helpful in revealing both expected and unexpected co-variations. Results show that previous experiences (student background) is an important factor behind high performance and that TLAs in the course are providing complementary knowledge. The main focus of this paper is on how the innovative approach of combining the use of concept maps and MVDA can provide useful understanding of possible correlations between student characteristics, their participation in TLAs and their performance in assessments in an ESD course. The use of concept maps was seen as useful in capturing important notions of ESD while the MVDA enabled quick analysis of the large data set. Highlights • Student data included concept map results (pre- and post-course) over 5 years. • Multivariate Data Analysis (MVDA) was used to analyze correlations. • The teaching helped students develop a more systemic and balanced view. • However, student background was also important. • MVDA was found useful for analysis and pedagogical reflection. [ABSTRACT FROM AUTHOR]

A significant increase in phosphorus-rich dairy wastewater coincides with a decrease in the availability of fossil phosphate rock resources in Europe. This confluence of events has led to the development of technologies for phosphorus recovery from dairy wastewater. This study aims to inform and guide such development with regard to life cycle environmental impacts prior to their implementation in dairy contexts. With the lack of inventory data at this point and the non-existence of earlier life cycle assessments on the use of phosphorus recovery technologies in a dairy context in literature, we performed a meta-analysis where we extracted and compared published results on life cycle environmental impacts from two fields (1) dairy industries, with a focus on the dairy wastewater treatment and (2) phosphorus recovery technologies in a municipal wastewater treatment context. The results show that despite its intended effect, normal dairy wastewater treatment in many cases still contributes significantly to eutrophication. Most of the phosphorus recovery technologies examined here exhibited a lower global warming potential and cumulative energy demand than those of dairy wastewater treatment processes. It indicates that problem shifting could be avoided when phosphorus recovery is introduced. However, no technologies involving incineration have had the impact of acidification reported which represents a potential knowledge gap since impacts are expected related to incineration emissions. A comparison between the extracted data for phosphorus recovery technologies shows that there are lower impacts related to technologies that recover phosphorus from the liquid phase, than from sludge or ash. • Meta-analysis of published life cycle assessment studies. • Environmental assessment of a conceptual system: P recovery from dairy wastewater. • Three environmental impact categories allowed cross-comparison: CED, GWP, and AP. • The P recovery technologies bring a low impact for CED and GWP. [ABSTRACT FROM AUTHOR]

The concept of perspectives is important in discussions about the multidimensionality of sustainability problems and the need to consider many different aspects when dealing with them. This paper aims to facilitate discussions among both educators and researchers about didactical approaches to developing students’ abilities to deal with the multidimensionality of sustainability challenges through the use of multiple perspectives. For this purpose, a theoretical framework was developed that describes perspectives in terms of a set of general characteristics, as well as a number of ways in which students can develop and reflect on perspectives. Development of the framework was supported by a qualitative content analysis of transcripts from interviews with undergraduate engineering students in Sweden. [ABSTRACT FROM PUBLISHER]

Global population growth and rising living standards are increasing apparel consumption. Consequently, consumption of resources and generation of textile waste are increasing. According to the Swedish Environmental Protection Agency, textile consumption increased by 40% between the years 2000 and 2009 in Sweden. Given that there is currently no textile recycling plant in Sweden, the aim of this article is to explore the potential environmental benefits of various textile recycling techniques and thereby direct textile waste management strategies toward more sustainable options. Three different recycling techniques for a model waste consisting of 50% cotton and 50% polyester were identified and a life cycle assessment (LCA) was made to assess the environmental performance of them. The recycling processes are: material reuse of textile waste of adequate quality; separation of cellulose from polyester using N-methylmorpholine-N-oxide as a solvent; and chemical recycling of polyester. These are compared to incineration, representing conventional textile waste treatment in Sweden. The results show that incineration has the highest global warming potential and primary energy usage. The material reuse process exhibits the best performance of the studied systems, with savings of 8 tonnes of carbon dioxide equivalents (CO2-eq) and 164 gigajoules (GJ) of primary energy per tonne of textile waste. Sensitivity analyses showed that results are particularly sensitive to the considered yields of the processes and to the choice of replaced products. An integration of these recycling technologies for optimal usage of their different features for treatment of 1 tonne of textile waste shows that 10 tonnes CO2-eq and 169 GJ of primary energy could be saved. [ABSTRACT FROM AUTHOR]

The legislative framework in force in Europe entails restrictive effluent standards for sensitive areas, and quite severe restrictions on the properties of residual sewage sludge, both for landfill disposal and for agricultural use. Several technologies and management strategies have been proposed and applied in wastewater treatment plants to minimise sludge production and contamination. However, their techno-economic and environmental performance has to be carefully evaluated. The ROUTES project, funded within the EU Seventh Framework programme, aims to find new routes for wastewater treatment and sludge management and thereby guide EU members in their future choices. Within this project, the authors have developed and applied a procedure for technoeconomic- environmental assessment of new wastewater and sludge processing lines in comparison to reference plants. The reference plants are model conventional plants that experience different types of problems and the new plants are modified plants in which different innovative technologies have been added to solve these problems. The procedure involves a rating of selected technical issues, estimates of operating costs and an assessment of environmental impacts from a life cycle perspective. This paper reports on the procedure and shows examples of results. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to report on methods developed, within a three-year Education for Sustainable Development (ESD) project at Chalmers University of Technology in Gothenburg, Sweden, to achieve a higher degree of embedding of ESD in engineering programmes. The major emphasis is on methods used, results achieved and lessons learned from the work. Design/methodology/approach – The basic idea that methods and activities were built on was that the only way to achieve long-term changes is to increase the motivation and capacity of lecturers and program directors to perform the required changes. Findings – Activities that were developed and tested focused on coaching discussions and on workshops for teachers, gathering teachers from one programme at a time. These activities aimed at starting learning processes in individuals. Special care was taken into keeping the feeling of responsibility and initiative in the faculty members within the programmes. A special "resource group" of experienced ESD teachers was available as support for programme directors and lecturers. Originality/value – The methods reported on are further developments of a method that has been used in Delft University of Technology (the Individual Interaction Method) in the Netherlands. The experiences from Chalmers are discussed in such a way that they provide useful insights for others aiming at similar changes at university. [ABSTRACT FROM AUTHOR]

Batteries are enablers for reducing fossil‐fuel dependency and climate‐change impacts. In this study, a prospective life cycle assessment (LCA) of large‐scale production of two different sodium‐ion battery (SIB) cells is performed with a cradle‐to‐gate system boundary. The SIB cells modeled have Prussian white cathodes and hard carbon anodes based only on abundant elements and thus constitute potentially preferable options to current lithium‐ion battery (LIB) cells from a mineral resource scarcity point of view. The functional unit was 1 kWh theoretical electricity storage capacity, and the specific energy density of the cells was 160 Wh/kg. Data for the cathode active material come from a large‐scale facility under construction and data for the SIB cell production is based on a large‐scale LIB cell gigafactory. For other SIB cell materials, prospective inventory data was obtained from a generic eight‐step procedure developed, which can be used by other LCA practitioners. The results show that both SIB cells indeed have considerably lower mineral resource scarcity impacts than nickel‐manganese‐cobalt (NMC)‐type LIB cells in a cradle‐to‐gate perspective, while their global warming impacts are on par. Main recommendations to SIB manufacturers are to source fossil‐free electricity for cell production and use hard carbon anodes based on lignin instead of phenolic resin. Additionally, since none of the assessed electrolytes had clearly lower cradle‐to‐gate impacts than any other, more research into SIB electrolyte materials with low environmental and resource impacts should be prioritized. An improvement of the SIB cell production model would be to obtain large‐scale production data specific to SIB cells. [ABSTRACT FROM AUTHOR]

Screening the life cycle assessment literature for information and recalculating extracted results was proven useful for identifying environmental challenges and opportunities in new, but related, contexts at early stages of technology development. The method was applied to carbon fiber reinforced polymers, a material of growing importance in industrial applications where a strong and/or light material is needed, such as in aircrafts and road vehicles. Many technology development efforts with the purpose of further improving such composite materials are on-going, in particular regarding the origin of carbon fibers. Using lignin as a bio-based feedstock and various recycling techniques have been suggested. However, these technologies do not yet exist at a scale that would enable a meaningful life cycle inventory, while the need for environmental guidance is urgent in order to ensure that only the more promising development paths are pursued before lock-in occurs. With a specific focus on the shift to lignin as a feedstock for carbon fibers and on recycled carbon fibers in composites, this article not only illustrates the type of information that can be obtained from mining and refining information from earlier life cycle assessment studies, but it also provides direct guidance on environmental opportunities and challenges specific for carbon fiber reinforced polymers. Thereby, it informs both technology development efforts and environmental assessment efforts. Amongst other things, the analysis reveals that an important factor behind the environmental impact of composites is the energy demand in carbonization of the carbon fibers and that both the shift to lignin-based and to recycled carbon fibers can potentially reduce this environmental impact. However, assessments of both lignin (as an output from a multifunctional process) and recycled carbon fibers (as an output from end-of-life activities) are connected to challenges related to the allocation of environmental impacts in an environmental assessment. Extracting and refining information from the literature proved useful for the specific task but remains to be tested in other fields of emerging technologies. • Replacing materials with CFRP decreased energy use in less than half of the cases. • The use of lignin as a raw material can decrease the impact of carbon fibers. • Recycling carbon fibers was shown to decrease energy use significantly. • Using recycled carbon fibers was more beneficial than using lignin as a raw material. [ABSTRACT FROM AUTHOR]

In recent years, there has been increasing interest within the engineering education research community to prepare engineering students to address wicked problems (WPs) such as climate change, resource scarcity and violent conflict. Previous research suggests that engineering students are able to address WPs if they are given adequate support, but there is a lack of research on what kinds of support are needed. This paper aims to reduce this gap by reporting on students' performance in, and approaches to, addressing WPs when different scaffolding strategies were used in different parts of a rubric-based intervention. The intervention aimed to provide undergraduate engineering students with an understanding of the nature of WPs and with a structured way of addressing them. For each part of the intervention, we discuss affordances for learning provided by the different scaffolding strategies. The results suggest that strong cognitive scaffolding can support students' understanding of the nature of WPs and students' performance in written responses to WPs, but possibly also limits deep engagement with WPs and transfer of learning to other contexts. [ABSTRACT FROM AUTHOR]

We present a life cycle assessment (LCA) study of a lithium/sulfur (Li/S) cell regarding its energy use (in electricity equivalents, kWh el ) and climate change (in kg carbon dioxide equivalents, CO 2 eq) with the aim of identifying improvement potentials. Possible improvements are illustrated by departing from a base case of Li/S battery design, electricity from coal power, and heat from natural gas. In the base case, energy use is calculated at 580 kWh el kWh −1 and climate change impact at 230 kg CO 2 eq kWh −1 of storage capacity. The main contribution to energy use comes from the LiTFSI electrolyte salt production and the main contribution to climate change is electricity use during the cell production stage. By (i) reducing cell production electricity requirement, (ii) sourcing electricity and heat from renewable sources, (iii) improving the specific energy of the Li/S cell, and (iv) switching to carbon black for the cathode, energy use and climate change impact can be reduced by 54 and 93%, respectively. For climate change, our best-case result of 17 kg CO 2 eq kWh −1 is of similar magnitude as the best-case literature results for lithium-ion batteries (LIBs). The lithium metal requirement of Li/S batteries and LIBs are also of similar magnitude. [ABSTRACT FROM AUTHOR]

Nanocellulose is a bionanomaterial with many promising applications, but high energy use in production has been described as a potential obstacle for future use. In fact, life cycle assessment studies have indicated high life cycle energy use for nanocellulose. In this study, we assess the cradle-to-gate environmental impacts of three production routes for a particular type of nanocellulose called cellulose nanofibrils (CNF) made from wood pulp. The three production routes are (1) the enzymatic production route, which includes an enzymatic pretreatment, (2) the carboxymethylation route, which includes a carboxymethylation pretreatment, and (3) one route without pretreatment, here called the no pretreatment route. The results show that CNF produced via the carboxymethylation route clearly has the highest environmental impacts due to large use of solvents made from crude oil. The enzymatic and no pretreatment routes both have lower environmental impacts, of similar magnitude. A sensitivity analysis showed that the no pretreatment route was sensitive to the electricity mix, and the carboxymethylation route to solvent recovery. When comparing the results to those of other carbon nanomaterials, it was shown that in particular CNF produced via the enzymatic and no pretreatment routes had comparatively low environmental impacts. [ABSTRACT FROM AUTHOR]

The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2-9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28 600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series. [ABSTRACT FROM AUTHOR]

Abstract: This paper reports on a literature survey on available approaches for the assessment of product sustainability, with a specific focus on assessing the replacement of non-renewable petroleum-based materials with renewable wood-based materials in absorbent hygiene products. The results are contrasted to needs in a specific material development project. A diverse number of methods exist that can help in assessing different product sustainability characteristics for parts of or whole product life cycles. None of the assessment methods found include guidelines for how to make a case-specific interpretation of sustainability and there is a general lack of assessment parameters that can describe considerations in the comparison between the use of wood or petroleum as main raw material. One reason for this is lack of knowledge and/or consensus on how to describe and assess impacts of land and water use, e.g. on ecosystem services, different types of resource depletion and social impacts. [Copyright &y& Elsevier]

Purpose – The purpose of this paper is to present the strategy used for achieving change towards sustainability at Chalmers University of Technology (Chalmers). Examples of how this strategy has been used are described and discussed, and exemplified with different lines of activities in a project on Education for Sustainable Development, the ESD project. Design/methodology/approach – The strategy consists of three important building blocks: Create a neutral arena; Build on individual engagement and involvement; and Communicate a clear commitment from the management team. The analysis is made along three different lines of activities in the ESD project: The work to improve the quality of the compulsory courses on sustainable development; The efforts to integrate ESD into educational programmes; and The work to collect and spread information on good teaching practices within ESD. Some other related examples where the strategy has been applied are also presented. Findings – The ESD project functioned as a neutral arena since it was not placed at any specific department but rather engaged participants from many departments. This neutral arena has been important, for example, to increase the willingness of teachers to share their good teaching examples. The process was successful in creating a shared responsibility and for starting learning processes in many individuals by the involvement of a broad range of educational actors at Chalmers. The strong and clear commitment from the management team has worked as a driving force. Originality/value – This paper can provide valuable input to universities that struggle with change processes. [ABSTRACT FROM AUTHOR]

Abstract Many outdoor garments are impregnated to make them water and, in some cases oil repellent, but the impregnation agents can be hazardous to human health and the environment. Some examples of such hazardous impregnation agents include per- and polyfluoroalkyl substances. To reduce the risks related to these fluorinated substances, a phase-out is necessary, and voluntary avoidance by consumers may be one way to make this happen. This experimental survey investigates the extent to which information about the hazardous properties of fluorinated substances affects consumer willingness-to-pay for alternative outdoor garments without hazardous chemicals. The experiment was conducted by means of a questionnaire distributed to more than 4000 Swedish respondents via the Laboratory of Opinion Research's Citizen Panel. The results show a generally high willingness-to-pay, and that the effects of providing information are higher when the price increase is high. This suggests that there is room for a price increase if the non-hazardous options are more expensive. This survey experiment indicates that the Swedish general public is ready for substitution to garments without hazardous fluorinated chemicals if the alternative provides an identical function. Information campaigns, however, will have limited ability to increase the willingness-to-pay for an alternative as it is already high. Despite the general willingness of the Swedish public to choose less hazardous options, legislative measures may potentially be the most effective action when supply chains are opaque and information to consumers is limited. Highlights • High public readiness for substitution of hazardous PFAS in outdoor garments. • Information about chemical hazards had effect on willingness-to-pay (WTP). • Room for a price increase if the non-hazardous options are more expensive. • Limited ability to increase the WTP for an alternative when WTP is already high. [ABSTRACT FROM AUTHOR]

Wastewater treatment plant (WWTP) nutrient recovery has recently gained traction in the search for new pathways for fertilizer production. In particular, concentrated waste streams such as reject water from sludge digestion are suitable. The environmental impact of a novel nutrient recovery technology using a membrane contactor (NPHarvest) was examined with an environmental life cycle assessment (LCA). Impact hotspots were benchmarked against a comparable technology (struvite precipitation and ammonia stripping), and the impacts of the two technologies were found to be similar for most studied environmental impact categories. To allow for the inclusion of effects on other parts of the WWTP while limiting the general system boundaries to the reject water treatment, a novel approach to capture the main line impact was developed. The effects on the main line contributed substantially to the overall results. The overall results indicated clear nutrient recovery benefits related to substituted materials in mineral fertilizer production. Additionally, reject water nutrient recovery provided even greater benefits due to reduced N 2 O emissions and the reduced use of precipitation chemicals in the WWTP main line. Nonetheless, both nutrient removal and recovery were necessary for the two technologies to reach a net zero climate impact in their current pilot scales. Further development of the NPHarvest technology—such as mitigating NH 3 emissions, exploring alternative input chemicals and optimizing energy consumption (especially for crystallizing the ammonium salt solution that is produced)—is recommended before full-scale implementation. [Display omitted] • A novel LCA modelling approach was developed for the impact of chemical nutrient recovery on main line treatment process. • Main line impact contributes to the results as the overall environmental impact is reduced by the decreased N and P load. • Comparison between technologies of different efficiencies was conducted by the MLI-model and fertilizers substitution. [ABSTRACT FROM AUTHOR]

This paper is aimed at evaluating, from a techno-economic and environmental point of view, the performance of an existing wastewater treatment plant in which the traditional biological section is upgraded with an innovative Sequencing Batch Biofilter Granular Reactor. Two scenarios were simulated in order to model and assess the performances of conventional (CAS, Conventional Activated Sludge) and innovative solutions, based on mass balances, techno-economic evaluation and environmental assessment. The results showed that converting the activated sludge process into an SBBGR allows to achieve a drastic reduction in sludge production (up to 75% as volatile suspended solids). Furthermore, the secondary sedimentation and sludge stabilization units can be dismissed, reducing the area requirement (up to 50%). The technical assessment is mainly positive, with the electric energy consumption being the only critical item. The higher energy demand of the upgraded plant (about 25% more than the conventional treatment) is mainly associated with the recycle flow in the SBBGR system. Although the economic sustainability of the upgraded plant depends on local conditions, it can be considered to be likely favourable: sludge disposal and materials & reagents costs, together with the investment for plant reconstruction are those items that should be carefully evaluated before upgrading the CAS plant with SBBGR technology. The environmental assessment shows also mostly positive results, although it points to the increased phosphorus concentration in the effluent as a potentially critical issue and it highlights the electricity use and the increased nitrous oxide generation as other matters that need to be carefully checked in real case application. [ABSTRACT FROM AUTHOR]

In this paper, the potential impacts in the techno-environmental performance of a municipal wastewater treatment plant with integrated mixed-microbial-culture polyhydroxyalkanoate (PHA) production are presented for the first time. A life cycle assessment was conducted based on mass and energy balances. The techno-environmental performance was evaluated for five wastewater treatment configurations: a reference case and four alternative processes producing PHA-rich biomass using influent municipal wastewater as the only organic carbon source. The integration of PHA-rich biomass production into a municipal wastewater treatment plant with sludge digestion sustains the overall conversion yield for total products of biogas and PHA-rich biomass (around 0.26 gCOD products per influent gCOD treated). PHA production integration has the potential to improve the overall environmental performance with respect to the reference case. Even when no benefits were accounted for substitutions related to the biogas and PHA-rich biomass, similar or improved environmental performances were estimated for all four alternatives for global warming potential, acidification potential, terrestrial eutrophication potential, and photo-oxidant formation potential. When benefits were accounted from substitutions of electricity and heat co-generated from biogas and of PHA-rich biomass by pure-culture PHA-rich biomass from sugar fermentation, gains were even higher due to the diversion of carbon from biogas to PHA-rich biomass. Freshwater and marine eutrophication potentials were dependent on effluent specifications. Case-by-case process configurations influence the mass and energy balance and trade-offs of process integration. The production and export of PHA-rich biomass decreased the aeration requirements for COD and nitrogen removal; however, increased demands for heat, power and chemicals were incurred for the generation of volatile fatty acids from primary solids fermentation. The choice of nitrogen-removal approach (nitrification-denitrification vs. anammox) also impacted energy consumption. Using influent wastewater as the sole carbon supply, the energy balance and PHA production were sensitive to the efficiency of primary treatment and available flux of volatile fatty acids into PHA production. Other regional inputs of organic residuals may improve carbon recovery in the treatment facility. The improved environmental performance of the treatment configurations motivates the idea that individual municipal wastewater treatment plants may become suppliers of renewable raw materials of higher value than that of biogas and/or energy and heat today. [ABSTRACT FROM AUTHOR]

The environmental challenges associated with consumption of textiles have generally been investigated on product level in Life Cycle Assessment (LCA) studies. For social sustainability aspects, social hotspot analysis has instead been applied on the textile sector level. The aim with the industry sector approach developed by the authors was to enable assessment of different interventions in terms of how they contribute to reaching targets for environmental and social sustainability, on the sector level. The approach was tested in a case study on the Swedish apparel sector. The industry sector approach consists of three steps that address three different questions: 1) What is the current sustainability performance of the sector? 2) What is an acceptable sustainability performance for the sector? 3) Are proposed interventions enough to reach an acceptable sustainability performance? By answering these questions, it is possible to measure performance in relation to sector level targets and learn which types of interventions (technical improvements, behavioral changes, new business models, etc.), and which actors (manufacturers, retailers, consumers, authorities, etc.) that can potentially provide the greatest improvements. By applying the approach in the case study, conclusions could be drawn on whether specific interventions appear to be sufficient or not in relation to the set environmental targets. The influence of the interventions in relation to reaching targets for social sustainability was found to be the most difficult to measure due to lack of data. To spur the industry sector's stakeholders to actualize the full potential of the most effective environmental interventions, a scheme for structured evaluation of LCA results directed towards these prospective actors was developed. Based on the results from the study, actor-oriented advice could be provided. [ABSTRACT FROM AUTHOR]

As life cycle assessments are often conducted to provide decision support, it is important that impact assessment methodology is consistent with the intended decision context. The currently most used climate impact assessment metric, the global warming potential, and how it is applied in life cycle assessments, has for example been criticised for insufficiently accounting for carbon sequestration, carbon stored in long-lived products and timing of emission. The aim of this study is to evaluate how practitioners assess the climate impact of forest products and the implications of method choice for results and decision-making. To identify current common practices, we reviewed climate impact assessment practices in 101 life cycle assessments of forest products. We then applied identified common practices in case studies comparing the climate impact of a forest-based and a non-forest-based fuel and building, respectively, and compared the outcomes with outcomes of applying alternative, non-established practices. Results indicate that current common practices exclude most of the dynamic features of carbon uptake and storage as well as the climate impact from indirect land use change, aerosols and changed albedo. The case studies demonstrate that the inclusion of such aspects could influence results considerably, both positively and negatively. Ignoring aspects could thus have important implications for the decision support. The product life cycle stages with greatest climate impact reduction potential might not be identified, product comparisons might favour the less preferable product and policy instruments might support the development and use of inefficient climate impact reduction strategies. [ABSTRACT FROM AUTHOR]

In this work we have performed a feasibility study of two upgrading alternatives for sewage sludge stabilization aimed to the reduction of the produced sludge and to the improvement of its qualitative characteristics with respect to its final destination: agricultural use or incineration. The first upgrading (1) proposes the separated thickening: primary sludge is thickened by gravity while dynamic thickening is applied to secondary sludge. The second upgrading (2) introduces a post-aerobic digestion stage (after the anaerobic one), in addition to separate thickening. Technical-economic and environmental assessments have been performed in comparison to a conventional wastewater treatment plant, which operates with gravity thickening and anaerobic digestion of mixed sludge. In the post-aerobic stage, operated with intermittent aeration, additional volatile solids removal of 45% and nitrification and denitrification efficiencies of 97% and 70%, respectively, were achieved. Both upgrading alternatives gained a positive technical evaluation with the only exceptions of the item “ Thermal energy consumption ” in upgrading 1 for agricultural reuse, and, to a minor extent, the “ Energy available for external recovery ” for incineration in both upgrading options. Cost analysis showed that the two upgrading alternatives are generally cheaper than the conventional plant, even if the results are dependent on local conditions, which have to be considered. Results of the environmental assessment showed that the upgrades with incineration perform better than the reference for all impact categories except freshwater eutrophication, with upgrading 2 as the best option. For the agricultural use, different results were obtained for the different impact categories with critical aspects mainly related to phosphorus and ammonia emissions for upgrading 1. [ABSTRACT FROM AUTHOR]

Risk assessment (RA) and life cycle assessment (LCA) are two analytical tools used to support decision making in environmental management. This study reviewed 30 environmental assessment case studies that claimed an integration, combination, hybridization, or complementary use of RA and LCA. The focus of the analysis was on how the respective case studies evaluated emissions of chemical pollutants and pathogens. The analysis revealed three clusters of similar case studies. Yet, there seemed to be little consensus as to what should be referred to as RA and LCA, and when to speak of combination, integration, hybridization, or complementary use of RA and LCA. This paper provides clear recommendations toward a more stringent and consistent use of terminology. Blending elements of RA and LCA offers multifaceted opportunities to adapt a given environmental assessment case study to a specific decision making context, but also requires awareness of several implications and potential pitfalls, of which six are discussed in this paper. To facilitate a better understanding and more transparent communication of the nature of a given case study, this paper proposes a "design space" (i.e., identification framework) for environmental assessment case studies blending elements of RA and LCA. Thinking in terms of a common design space, we postulate, can increase clarity and transparency when communicating the design and results of a given assessment together with its potential strengths and weaknesses. [ABSTRACT FROM AUTHOR]

Nowadays, several technologies and management strategies are proposed for upgrading wastewater treatment plants (WWTPs) in order to improve sludge stabilization or minimize sludge production. In order to make sure that this leads to overall improvements, their techno-economic and environmental performance has to be carefully evaluated. In response to this, the techno-economic and environmental performance was assessed for a considered model reference WWTP upgraded with separate treatment and disposal for primary and secondary sludge to provide guidance to research, policy and investment efforts. This paper departs in an experimental campaign carried out within the EU project “ROUTES” and describes an assessment of an upgrade of a WWTP, involving wet oxidation of primary sludge and thermophilic anaerobic digestion (integrated with thermal hydrolysis pre-treatment) for secondary sludge. The reference plant and the upgrade implied different disposal routes for the resulting sludges: incineration for the stabilized sludge deriving from the reference WWTP; agricultural land application for the secondary stabilized sludge from the upgraded plant and landfilling for the solid residue deriving from the wet oxidation process (as non-hazardous waste). The mass balance carried out for both reference and upgraded WWTPs showed a reduction of total sludge production (up to 45%) for the upgraded WWTP. The additional energy demand of the upgraded solution (+22.4 Wh/(PE d), PE: population equivalent) was partially balanced by the electric energy produced by combined heat and power unit installed in the upgraded WWTP (−18.08 Wh/(PE d)). The integrated assessment showed that the upgraded solution, although resulting in an increase of WWTP technical complexity, may contribute to environmental and economic advantages. The paper provides guidance in terms of which aspects need a more thorough evaluation when this upgrade is considered in real cases. [ABSTRACT FROM AUTHOR]

Life cycle assessment (LCA) and quantitative risk assessment (QRA) are commonly used to evaluate potential human health impacts associated with proposed or existing infrastructure and products. Each approach has a distinct objective and, consequently, their conclusions may be inconsistent or contradictory. It is proposed that the integration of elements of QRA and LCA may provide a more holistic approach to health impact assessment. Here we examine the possibility of merging LCA assessed human health impacts with quantitative microbial risk assessment (QMRA) for waterborne pathogen impacts, expressed with the common health metric, disability adjusted life years (DALYs). The example of a recent large-scale water recycling project in Sydney, Australia was used to identify and demonstrate the potential advantages and current limitations of this approach. A comparative analysis of two scenarios – with and without the development of this project - was undertaken for this purpose. LCA and QMRA were carried out independently for the two scenarios to compare human health impacts, as measured by DALYs lost per year. LCA results suggested that construction of the project would lead to an increased number of DALYs lost per year, while estimated disease burden resulting from microbial exposures indicated that it would result in the loss of fewer DALYs per year than the alternative scenario. By merging the results of the LCA and QMRA, we demonstrate the advantages in providing a more comprehensive assessment of human disease burden for the two scenarios, in particular, the importance of considering the results of both LCA and QRA in a comparative assessment of decision alternatives to avoid problem shifting. The application of DALYs as a common measure between the two approaches was found to be useful for this purpose. [ABSTRACT FROM AUTHOR]

In Life Cycle Assessments (LCAs) of biorefinery products, a common challenge is the choice of method for allocating environmental burdens of multifunctional processes (feedstock cultivation and biorefinery processes), a choice which can substantially influence LCA results and hence decision-making. The aim of this paper is to explore how this choice influences results and in which decision contexts the choice is particularly important. To do this, we tested six allocation methods in a case study of a biorefinery using pulpwood as feedstock. Tested methods included: main product bears all burden, substitution, traditional partitioning methods (based on economic value and exergy), a hybrid method combining elements of substitution and partitioning, and an alternative hybrid method developed by us, which allocates less environmental burden to co-products with a high potential to mitigate environmental burdens. The methods were tested in relation to decision contexts and LCA questions of relevance for biorefineries. The results indicate that the choice of allocation method deserves careful attention, particularly in consequential studies and in studies focussed on co-products representing relatively small flows. Furthermore, the alternative hybrid allocation method is based on a logical rationale – favouring products with higher substitution potential – and has some other potential benefits. However, in cases where the scales of co-product flows are of different orders of magnitude, the method yields extreme results that could be difficult to interpret. Results also show that it can be important with consistent allocation for both cultivation and biorefinery processes, particularly when substitution is applied. [ABSTRACT FROM AUTHOR]

Resource recovery from sewage sludge has the potential to save natural resources, but the potential risks connected to human exposure to heavy metals, organic micropollutants, and pathogenic microorganisms attract stakeholder concern. The purpose of the presented study was to include pathogen risks to human health in life cycle assessment (LCA) of wastewater and sludge management systems, as this is commonly omitted from LCAs due to methodological limitations. Part 1 of this article series estimated the overall pathogen risk for such a system with agricultural use of the sludge, in a way that enables the results to be integrated in LCA. This article (part 2) presents a full LCA for two model systems (with agricultural utilization or incineration of sludge) to reveal the relative importance of pathogen risk in relation to other potential impacts on human health. The study showed that, for both model systems, pathogen risk can constitute an important part (in this study up to 20%) of the total life cycle impacts on human health (expressed in disability adjusted life years) which include other important impacts such as human toxicity potential, global warming potential, and photochemical oxidant formation potential. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cradle-to-grave life cycle assessments are preferable for the studied technology. [•] Multifunctionality creates an allocation problem – we suggest a solution. [•] Due to the electricity intensive technology the results show regional dependency. [•] Water use has not been assessed in previous studies but is potentially relevant. [Copyright &y& Elsevier]

Abstract: In technical Research and Development (R&D) projects, a Life Cycle Assessment (LCA) of the technology under development is sometimes carried out. Particularly in inter-organisational R&D projects, the roles of LCAs tend to be unclear and arbitrary, and as a consequence, LCA work is not adequately designed for the needs of the project. There is a need for research on how to choose an appropriate role for LCA in such projects and how to plan LCA work accordingly. We have identified some possible roles of LCA in inter-organisational R&D projects and used experiences from LCA work in different such projects to identify four project characteristics that are decisive for what roles the LCA can have. The project characteristics are: (i) the project's potential influence on environmental impacts, (ii) the degrees of freedom available for the technical direction of the project, (iii) the project's potential to provide required input to the LCA, and (iv) access to relevant audiences for the LCA results. We discuss how evaluation of these project characteristics can help project commissioners, project managers and LCA practitioners to deliberately choose appropriate roles of LCA in inter-organisational R&D projects and plan projects for efficient use of LCA. [Copyright &y& Elsevier]

Animal slurry management is associated with a range of impacts on fossil resource use and the environment. The impacts are greatest when large amounts of nutrient-rich slurry from livestock production cannot be adequately utilised on adjacent land. To facilitate nutrient redistribution, a range of different technologies are available. This study comprised a life cycle assessment of the environmental impacts from handling 1000kg of pig slurry ex-animal. Application of untreated pig slurry onto adjacent land was compared with using four different treatment technologies to enable nutrient redistribution before land application: (a) separation by mechanical screw press, (b) screw press separation with composting of the solid fraction, (c) separation by decanter centrifuge, and (d) decanter centrifuge separation with ammonia stripping of the liquid fraction. Emissions were determined based on a combination of values derived from the literature and simulations with the Farm-N model for Danish agricultural and climatic conditions. The environmental impact categories assessed were climate change, freshwater eutrophication, marine eutrophication, terrestrial acidification, natural resource use, and soil carbon, nitrogen and phosphorus storage. In all separation scenarios, the liquid fraction was applied to land on the pig-producing (donor) farm and the solid fraction transported to a recipient farm and utilised for crop production. Separation, especially by centrifuge, was found to result in a lower environmental impact potential than application of untreated slurry to adjacent land. Composting and ammonia stripping either slightly increased or slightly decreased the environmental impact potential, depending on the impact category considered. The relative ranking of scenarios did not change after a sensitivity analysis in which coefficients for field emissions of nitrous oxide, ammonia and phosphorus were varied within the range cited in the literature. Therefore, the best technology to implement in a given situation depends on the environmental problem in question, local policy, cost and practicality. [Copyright &y& Elsevier]

Abstract: In this study we investigate how indicators for energy use are applied in a set of life cycle assessment (LCA) and energy analysis case studies of biofuels. We found five inherently different types of indicators to describe energy use: (1) fossil energy, (2) secondary energy, (3) cumulative energy demand, (4) net energy balance, and (5) total extracted energy. It was also found that the examined reports and articles, the choice of energy use indicator was seldom motivated or discussed in relation to other energy use indicators. In order to investigate the differences between these indicators, they were applied to a case. The life cycle energy use of palm oil methyl ester was calculated and reported using these five different indicators for energy use, giving considerably different output results. This is in itself not unexpected, but indicates the importance of clearly identifying, describing and motivating the choice of energy use indicator. The indicators can all be useful in specific situations, depending on the goal and scope of the individual study, but the choice of indicators need to be better reported and motivated than what is generally done today. [Copyright &y& Elsevier]

Purpose – The aim of this study is to contribute to the quality improvement and long-term strategic development of education for sustainable development (ESD) in engineering education curricula. Design/methodology/approach – The content in 70 courses in environment and SD were characterized and quantified using course document text analysis. Additionally, two questionnaires were sent to students and alumni at Chalmers, and interviews and focus group discussions were conducted with representatives from 16 Swedish companies and five organizations. Findings – It was found that industry demands a broader range of competences in SD amongst engineers in general than what is currently provided. In total, 35 per cent of alumni claim they encounter sustainability issues from sometimes to daily in their work. However, only half of them believe they possess enough competences to make decisions from a sustainability perspective. Quantity, coverage and the level of integration in the educational programme all appear to be important for the students' perceived competences on SD and for the importance that they put on achieving SD. Originality/value – Earlier research has reported on how to further develop the idea and design of ESD and on competence needs in general. Few attempts have been made to assess industry's needs of competences in SD. This paper sheds light on how engineering universities educate for SD and benchmarks this to industry's needs in an exploratory case study, using Chalmers as an example. [ABSTRACT FROM AUTHOR]

Abstract: A life cycle assessment of hydrotreated vegetable oil (HVO) biofuel was performed. The study was commissioned by Volvo Technology Corporation and Volvo Penta Corporation as part of an effort to gain a better understanding of the environmental impact of potential future biobased liquid fuels for cars and trucks. The life cycle includes production of vegetable oil from rape, oil palm or Jatropha, transport of the oil to the production site, production of the HVO from the oil, and combustion of the HVO. The functional unit of the study is 1kWh energy out from the engine of a heavy-duty truck and the environmental impact categories that are considered are global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and embedded fossil production energy. System expansion was used to take into account byproducts from activities in the systems; this choice was made partly to make this study comparable to results reported by other studies. The results show that HVO produced from palm oil combined with energy production from biogas produced from the palm oil mill effluent has the lowest environmental impact of the feedstocks investigated in this report. HVO has a significantly lower life cycle GWP than conventional diesel oil for all feedstocks investigated, and a GWP that is comparable to results for e.g. rape methyl ester reported in the literature. The results show that emissions from soil caused by microbial activities and leakage are the largest contributors to most environmental impact categories, which is supported also by other studies. Nitrous oxide emissions from soil account for more than half of the GWP of HVO. Nitrogen oxides and ammonia emissions from soil cause almost all of the life cycle EP of HVO and contribute significantly to the AP as well. The embedded fossil production energy was shown to be similar to results for e.g. rape methyl ester from other studies. A sensitivity analysis shows that variations in crop yield and in nitrous oxide emissions from microbial activities in soil can cause significant changes to the results. [Copyright &y& Elsevier]

Abstract: Four handling options for sewage sludge were studied from an environmental system''s perspective using life cycle assessment. The studied options were restoration of mining areas, composting with other biomaterials for use on golf courses, hygienisation through storage for agricultural use, and supercritical water oxidation with phosphorus recovery. The results are discussed in terms of impact on global warming, acidification, eutrophication, and the use of finite resources and primary energy. A very large impact of including biogeochemical emissions from sludge handling and spreading on land can be seen. System expansions for replaced artificial fertilizers also had a major influence on the results. It is clear that it is important for the environmental outcome of sludge treatment options that biogeochemical emissions from sludge are minimized and that nutrients and other resources are utilized efficiently. [Copyright &y& Elsevier]