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The aim of this study was to assess the social impacts of microalgae-based systems for wastewater treatment and bioproducts recovery by using the Social Life Cycle Assessment (S-LCA) tool. In particular, two systems were analysed: 1) a system treating urban wastewater, and 2) another system treating wastewater from the food industry. Moreover, these alternatives were compared to 3) a system for bioproducts production from microalgae grown in a standard growth medium. The recovered bioproducts in all the systems considered were: natural pigments, biogas and digestate, which can be reused as biofertilizer. Results showed that the scenario using standard growth medium was the one showing the best results in all impacts and stakeholder categories (up to 24-fold lower impacts depending on the impact category). This was mainly due to: i) the simplicity of the system, which consequently improves health and safety for workers; ii) the absence of contaminants which consequently improves health and safety, acceptability and olfactory impact for both consumers and the local community; iii) the presence of well-established legislation, regulatory frameworks, and full-scale deployment, which benefit value chain actors and society. Overall, this study also identified several social factors hindering a transition towards a circular bioeconomy in the microalgae-based systems for the wastewater treatment and resource recovery sector. [Display omitted] • Social Life Cycle Assessment of microalgae-based systems was carried out. • Microalgae-based systems recovered natural pigments, biofertilizer and biogas. • Microalgae-based systems using wastewater and standard growth medium were compared. • Scenario using standard growth medium showed up to 24-fold lower impact. • Bottlenecks for full-scale deployment of microalgae-based systems were identified. [ABSTRACT FROM AUTHOR]

The first, and probably the most determining, decision that engineering teams need to make when facing the structural design of any infrastructure is the choice of both an appropriate material and the suitable structural typology for its components. Each component is required to satisfy technical and functional aspects imposed by standards and stakeholder. Currently, the aspects that are most frequently considered in decision-making processes are economic. Nevertheless, environmental and social criteria are also required if one aims at making sustainability-based decisions. In this regard, to the best of the authors' knowledge, very few tools or studies exist that can support decision-makers. The few that do exist, are rather limited, either because they fail to incorporate many relevant factors in the sustainability assessment of a project or because they only evaluate environmental and social impacts of a project as a whole. Although a global assessment is useful to gain a holistic understanding of impacts of a project and to compare them to other projects, it does not necessarily help engineering teams understand the impact of fundamental decisions made when designing individual structural components. Therefore, the aim of the present research paper is to develop a new method for the sustainability analysis of building structural components which has been specifically oriented to beams and girders. This is done by means of the Integrated Value Model for the Evaluation of Sustainability method, which is known by its Spanish acronym, MIVES (Modelo Integrado de Valor para una Evaluación Sostenible). This method draws on multi-attribute utility theory and that allows building an integrated value model as an approach for multi-criteria decision-making. The developed model has been applied to assess the sustainability of different alternatives of beams and trusts to support the non-accessible roof of a sports hall in Vila-seca, Spain. Different material types and structural typologies are analysed. The findings show that the most sustainable alternatives are timber and reinforced concrete trusses, which are actually two options that are seldom used in practice. • A model to evaluate the sustainability of structural elements is developed. • MIVES is proved to be an adequate sustainability assessment tool in these cases. • Girders and trusses made of timber, concrete and steel are analysed. • Timber and concrete trusses achieve the highest global sustainability indexes. [ABSTRACT FROM AUTHOR]

This paper focuses on the sustainability analysis of different constituent materials for sewerage pipes by using a specific multi - criteria decision making (MCDM) method based on the value analysis and the multi-attribute utility theory. The scientific added value of this research consists of developing a method that minimizes the subjectivity involved in the process of quantification and comparison of different alternatives of materials to construct sewerage pipelines. In this context, a requirements tree is defined to derive a non-dimensional sustainability index for each alternative. The method is also supported by use of value functions and weights assigned to each criteria and indicator part of this requirements tree. These value functions were established during seminars and questionnaires solved by specialists and senior managers from the Spanish public sector. Besides, the weights were derived from the use of an Analytical Hierarchical Process. The model is used to assess the sustainability of 8 alternatives including rigid reinforced and non-reinforced concrete pipes as well as flexible polypropylene, polyethylene, polyvinyl chloride and glass-fibre reinforced polyester pipes. Nominal diameters of 400, 800, 1200 and 2000 were chosen as those representatives for urban and rural sewerage networks. The conclusions obtained from the research confirm that the sustainability indexes are similar for diameters of 400 mm and below, independently of the material. In addition, it has been also concluded that concrete solutions are clearly better in terms of sustainability for wider diameters with respect to the other alternative materials. [ABSTRACT FROM AUTHOR]