Environmental evaluation of flocculation efficiency in the separation of the microalgal biomass of Scenedesmus sp. cultivated in full-scale photobioreactors.

In this paper the environmental evaluation of the separation process of the microalgal biomass Scenedesmus sp. from full-scale photobioreactors was carried out at the Research and Development Nucleus for Sustainable Energy (NPDEAS), with different flocculants (iron sulfate - FeCl3, sodium hydroxide - NaOH, calcium hydroxide - Ca(OH)2 and aluminum sulphate Al2(SO4)3, by means of the life cycle assessment (LCA) methodology, using the SimaPro 7.3 software. Furthermore, the flocculation efficiency by means of optical density (OD) was also evaluated. The results indicated that FeCl3 and Al2(SO4)3 were highly effective for the recovery of microalgal biomass, greater than 95%. Though, when FeCl3 was used, there was an immediate change in color to the biomass after the orange colored salt was added, typical with the presence of iron, which may compromise the biomass use according to its purpose and Al2(SO4)3 is associated with the occurrence of Alzheimer's disease, restricting the application of biomass recovered through this process for nutritional purposes, for example. Therefore, it was observed that sodium hydroxide is an efficient flocculant, promoting recovery around 93.5% for the ideal concentration of 144 mg per liter. It had the best environmental profile among the compared flocculant agents, since it did not cause visible changes in the biomass or compromise its use and had less impact in relation to acidification, eutrophication, global warming and human toxicity, among others. Thus, the results indicate that it is important to consider both flocculation efficiency aspects and environmental impacts to identify the best flocculants on an industrial scale, to optimize the process, with lower amount of flocculant and obtain the maximum biomass recovery and decrease the impact on the extraction, production, treatment and reuse of these chemical compounds to the environment. However, more studies are needed in order to evaluate energy efficiency of the process coupled with other microalgal biomass recovery technologies. In addition, studies with natural flocculants, other polymers and changes in pH are also needed, as these are produced in a more sustainable way than synthetic organic polymers and have the potential to generate a biomass free of undesirable contaminants.

LCIA framework and cross-cutting issues guidance within the UNEP-SETAC Life Cycle Initiative.

Increasing needs for decision support and advances in scientific knowledge within life cycle assessment (LCA) led to substantial efforts to provide global guidance on environmental life cycle impact assessment (LCIA) indicators under the auspices of the UNEP-SETAC Life Cycle Initiative. As part of these efforts, a dedicated task force focused on addressing several LCIA cross-cutting issues as aspects spanning several impact categories, including spatiotemporal aspects, reference states, normalization and weighting, and uncertainty assessment. Here, findings of the cross-cutting issues task force are presented along with an update of the existing UNEP-SETAC LCIA emission-to-damage framework. Specific recommendations are provided with respect to metrics for human health (Disability Adjusted Life Years, DALY) and ecosystem quality (Potentially Disappeared Fraction of species, PDF). Additionally, we stress the importance of transparent reporting of characterization models, reference states, and assumptions, in order to facilitate cross-comparison between chosen methods and indicators. We recommend developing spatially regionalized characterization models, whenever the nature of impacts shows spatial variability and related spatial data are available. Standard formats should be used for reporting spatially differentiated models, and choices regarding spatiotemporal scales should be clearly communicated. For normalization, we recommend using external normalization references. Over the next two years, the task force will continue its effort with a focus on providing guidance for LCA practitioners on how to use the UNEP-SETAC LCIA framework as well as for method developers on how to consistently extend and further improve this framework.

Bridging the Gaps in Social Life Cycle Assessment: Theoretical and Practical Contributions / Avanços à Avaliação Social do Ciclo de Vida: Contribuições Teóricas e Práticas

Abstract Sustainable development is based on three pillars: environment preservation, cost-effective production and human development. Within this context, emerges Life Cycle Assessment (LCA), a solid methodology for assessing the impact of products and services. Whereas Social LCA (S-LCA) is an early-stage approach, currently under development, requiring theoretical and methodological improvements. This study aimed at mapping the main gaps in S-LCA to identify potential contributions from the Psychology field. A preliminary literature review indicated several constraints: consensus between social indicators; methods for measuring subjective data; predominance of secondary data; underutilization of the Social Sciences, etc. Therefore, this study outlines multiples intersection points where the Social Sciences, more specifically, psychology could contribute to filling some of the theoretical and methodological gaps in S-LCA.

Resumo O desenvolvimento sustentável ocorre por três pilares: preservação do meio-ambiente, produção com custo econômico eficiente e desenvolvimento humano. Nesse contexto surge a Avaliação do Ciclo de Vida (ACV), que determina métodos para avaliação de impacto de produtos e serviços. A ACV Social (ACV-S) é uma abordagem em desenvolvimento, requerendo avanços à plena aplicação. Este estudo objetivou mapear as principais lacunas teórico-metodológicas da ACV-S para a identificação convergências com a psicologia. A revisão da literatura indicou diferentes lacunas: consenso entre indicadores sociais; métodos para mensuração de dados subjetivos; primazia de dados secundários; subemprego das Ciências Sociais etc. Assim, este estudo apontou pontos de interseção onde as Ciências Sociais, especificamente, a Psicologia poderá contribuir para preencher algumas das lacunas teórico-metodológicas da ACV-S.