Magdalena Svanström

Embedding sustainability in higher education through interaction with lecturers: Case studies from three European technical universities

In this paper, three universities compare their work on the integration of sustainable development into their educational programmes. The purpose is to show examples of how this can be done and to illustrate important generalised success factors. Methods used to achieve embedding of sustainability in curricula through individual interaction with teachers and other actors are described. The three universities are all technical universities with relatively high ambitions for their activities in relation to sustainable development.

Life cycle assessment of construction materials: the influence of assumptions in end-of-life modelling

PurposeThe nature of end-of-life (EoL) processes is highly uncertain for constructions built today. This uncertainty is often neglected in life cycle assessments (LCAs) of construction materials. This paper tests how EoL assumptions influence LCA comparisons of two alternative roof construction elements: glue-laminated wooden beams and steel frames. The assumptions tested include the type of technology and the use of attributional or consequential modelling approaches.MethodsThe study covers impact categories often considered in the construction industry: total and non-renewable primary energy demand, water depletion, global warming, eutrophication and photo-chemical oxidant creation. The following elements of the EoL processes are tested: energy source used in demolition, fuel type used for transportation to the disposal site, means of disposal and method for handling allocation problems of the EoL modelling. Two assumptions regarding technology development are tested: no development from today’s technologies and that today’s low-impact technologies have become representative for the average future technologies. For allocating environmental impacts of the waste handling to by-products (heat or recycled material), an attributional cut-off approach is compared with a consequential substitution approach. A scenario excluding all EoL processes is also considered.Results and discussionIn all comparable scenarios, glulam beams have clear environmental benefits compared to steel frames, except for in a scenario in which steel frames are recycled and today’s average steel production is substituted, in which impacts are similar. The choice of methodological approach (attributional, consequential or fully disregarding EoL processes) does not seem to influence the relative performance of the compared construction elements. In absolute terms, four factors are shown to be critical for the results: whether EoL phases are considered at all, whether recycling or incineration is assumed in the disposal of glulam beams, whether a consequential or attributional approach is used in modelling the disposal processes and whether today’s average technology or a low-impact technology is assumed for the substituted technology.ConclusionsThe results suggest that EoL assumptions can be highly important for LCA comparisons of construction materials, particularly in absolute terms. Therefore, we recommend that EoL uncertainties are taken into consideration in any LCA of long-lived products. For the studied product type, LCA practitioners should particularly consider EoL assumptions regarding the means of disposal, the expected technology development of disposal processes and any substituted technology and the choice between attributional and consequential approaches.

Life Cycle Assessment of Cellulose Nanofibrils Production by Mechanical Treatment and Two Different Pretreatment Processes

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.

Life cycle assessment of pig slurry treatment technologies for nutrient redistribution in Denmark

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 1000 kg 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.

Including pathogen risk in life cycle assessment of wastewater management. 1. Estimating the burden of disease associated with pathogens.

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.

Using the planetary boundaries framework for setting impact-reduction targets in LCA contexts

PurposeThe planetary boundaries (PBs) framework suggests global limits for environmental interventions which could be used to set global goals for reducing environmental impacts. This paper proposes a procedure for using such global goals for setting impact-reduction targets at the scale of products for use, for example, in life cycle assessment (LCA) contexts, e.g. as a basis for evaluating the potential of interventions to reduce the environmental impact of products.MethodsThe procedure consists of four steps: (i) identifying the PBs quantified in literature that correspond to an impact category which is studied in the product assessment context in question; (ii) interpreting what the identified PBs imply in terms of global impact-reduction targets; (iii) translating the outcome of (ii) to reduction targets for the particular global market segment to which the studied product belongs; and (iv) translating the outcome of (iii) to reduction targets for the studied product. The procedure requires some assumptions and value-based choices—the influence of these is tested by applying the procedure in a specific LCA context: a study of Swedish clothing consumption.Results and discussionThe application of the procedure in an LCA context suggested the need for eliminating all or nearly all impact of Swedish clothing consumption for most impact categories. Thus, it is improbable that a single type of impact-reduction intervention (e.g. technological development or changed user behaviour) is sufficient. The outcome’s strong dependence on impact category suggests that the procedure can help in prioritising among impact categories. Furthermore, the outcome exhibited a strong dependence on the chosen method for allocating the globally allowed impact between regions—this was tested by applying different principles identified in a literature review on the allocation of emissions rights. The outcome also strongly depended on the geographical scope—this was tested by changing the geographical scope from Sweden to Nigeria.ConclusionsThe proposed procedure is feasible to use for LCA practitioners and other environmental analysts, and data is available to apply the procedure in contexts with different geographical scopes. Value-based choices are, however, unavoidable and significantly influence the outcome, which accentuates the subjectivity and potentially controversial nature of allocating a finite impact space to certain regions, market segments and products. How to match PBs with appropriate LCA impact categories is an important area for future research.

Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 2. Quantitative Comparison of Pathogen Risk to Other Impacts on Human Health

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.

The university and transformation towards sustainability: The strategy used at Chalmers University of Technology

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.

Techno-economic and environmental assessment of sewage sludge wet oxidation.

Today, several technologies and management strategies are proposed and applied in wastewater treatment plants (WWTPs) to minimise sludge production and contamination. In order to avoid a shifting of burdens between different areas, their techno-economic and environmental performance has to be carefully evaluated. Wet oxidation (WO) is an alternative solution to incineration for recovering energy in sewage sludge while converting it to mostly inorganic residues. This paper deals with an experimentation carried out within the EU project “ROUTES”. A mass balance was made for a WWTP (500,000 person equivalents) in which a WO stage for sludge minimisation was considered to be installed. Both bench- and full-scale test results were used. Design of treatment units and estimation of capital and operational costs were then performed. Subsequently, technical and economic aspects were evaluated by means of a detailed methodology which was developed within the ROUTES project. Finally, an assessment of environmental impacts from a life cycle perspective was performed. The integrated assessment showed that for the specific upgrade considered in this study, WO technology, although requiring a certain increase of technical complexity at the WWTP, may contribute to environmental and economic advantages. The paper provides guidance in terms of which aspects need a more thorough evaluation in relation to the specific case in which an upgrade with WO is considered.

Environmental assessment of supercritical water oxidation and other sewage sludge handling options.

Sustainable development relies on the eco-efficient use of all flows in society; more value created out of each resource unit. Supercritical water oxidation (SCWO) can be used for treatment of wet organic waste. The technology has been under development for over 20 years but has not yet been fully commercialized. SCWO allows for complete oxidation of all organics in sewage sludge and almost complete recovery of the inherent energy, essentially without harmful emissions. In this paper, a life-cycle assessment (LCA) of sewage sludge SCWO (Aqua-Critox) is presented and the results are compared with LCA results for other sludge handling options: agricultural use, co-incineration with municipal solid waste, incineration with subsequent phosphorus extraction (Bio-Con) and sludge fractionation with phosphorus recovery (Cambi-KREPRO). For SCWO, beneficial utilization of the heat of reaction is of crucial importance for the outcome. The electricity consumed by pumping and the nitrous oxide produced are other important parameters. The best sludge handling option from an environmental point of view depends on what aspect is considered more important in the impact assessment. Regarding global warming, the energy recovery methods perform better than agricultural use.