Environmental impacts of freshwater use and suspended solids in life cycle assessment

Perturbation of natural ecosystems, namely by increasing freshwater use and its degradative use, as well as topsoil erosion by water of land-use production systems, have been emerging as topics of high environmental concern. Freshwater use has become a focus of attention in the last few years for all stakeholders involved in the production of goods, mainly agro-industrial and forest-based products, which are freshwater-intensive consumers, requiring large inputs of green and blue water. This thesis presents a global review on the available Water Footprint Assessment and Life Cycle Assessment (LCA)-based methods for measuring and assessing the environmental relevance of freshwater resources use, based on a life cycle perspective. Using some of the available midpoint LCA-based methods, the freshwater use-related impacts of a Portuguese wine (white ‘vinho verde’) were assessed. However, the relevance of environmental green water has been neglected because of the absence of a comprehensive impact assessment method associated with green water flows. To overcome this constraint, this thesis helps to improve and enhance the LCA-based methods by providing a midpoint and spatially explicit Life Cycle Impact Assessment (LCIA) method for assessing impacts on terrestrial green water flow and addressing reductions in surface blue water production caused by reductions in surface runoff due to land-use production systems. The applicability of the proposed method is illustrated by a case study on Eucalyptus globulus conducted in Portugal, as the growth of short rotation forestry is largely dependent on local precipitation. Topsoil erosion by water has been characterised as one of the most upsetting problems for rivers. Because of this, this thesis also focuses on the ecosystem impacts caused by suspended solids (SS) from topsoil erosion that reach freshwater systems. A framework to conduct a spatially distributed SS delivery to freshwater streams and a fate and effect LCIA method to derive site-specific characterisation factors (CFs) for endpoint damage on aquatic ecosystem diversity, namely on algae, macrophyte, and macroinvertebrates organisms, were developed. The applicability of this framework, combined with the derived site-specific CFs, is shown by conducting a case study on E. globulus stands located in Portugal as an example of a land use based system. A spatially explicit LCA assessment was shown to be necessary, since the impacts associated with both green water flows and SS vary greatly as a function of spatial location.

Extração de ácidos triterpénicos a partir da casca de eucalipto utilizando líquidos iónicos

Os recursos renováveis têm sido um forte alvo de investigação científica nos últimos anos, onde o aproveitamento de biomassa e seus resíduos para a obtenção de compostos de valor acrescentado, combustíveis e energia têm sido abordados no conceito de biorrefinaria integrada. As indústrias de papel geram quantidades significativas de resíduos, nomeadamente a casca de eucalipto que é atualmente queimada para a geração de energia. De forma a valorizar este resíduo, a presente dissertação teve como objetivo extrair compostos triterpénicos, a partir casca externa de Eucalyptus globulus, utilizando solventes de extração alternativos - soluções aquosas de líquidos iónicos (LIs) – para substituir os solventes orgânicos actualmente utilizados. Os ácidos triterpénicos apresentam um elevado interesse na indústria cosmética, farmacêutica e alimentar graças às suas propriedades antiinflamatórias, antitumurais, entre outras. Primeiramente, caracterizou-se a casca externa de Eucalyptus globulus, e posteriormente procedeu-se ao estudo de solubilidade de ácido ursólico (AU, utilizado como molécula modelo) a 25 ºC em soluções aquosas de LIs e surfactantes de modo a selecionar os solventes mais eficientes para a extração. Deste trabalho conclui-se que a capacidade surfactante das soluções aquosas de LIs, particularmente [C4C1im][C8H17SO4], [C16C1im]Cl e [C14C1im]Cl, desempenham um papel fundamental para a solubilização de AU em água, podendo aumentar quase 16000 vezes a sua solubilidade, e permitiu recuperar cerca de 89% deste composto com simples adição de água como anti-solvente. Por fim, compararam-se as quantidades de ácidos triterpénicos extraídas a partir da casca de eucalipto com soluções aquosas de [C14C1im]Cl, metanol e com extração em soxhlet com diclorometano.

Production of bioplastics from hydrolysates of paper industry by Haloferax mediterranei

The biorefinery concept has attracted much attention over the last decade due to increasing concerns about the use of fossil resources. In this context emerged the use of bioplastics, namely polyhydroxyalkanoates (PHA). PHA are biocompatible and biodegradable plastics that can be obtained from renewable raw materials and can constitute an alternative solution to conventional plastics. In this work, hydrolysed cellulose pulp, coming from Eucalyptus globulus wood cooking, was used as substrate to the PHA-storing bacteria Haloferax mediterranei. The hydrolysed pulp is rich in simple sugars, mainly glucose (81.96 g.L-1) and xylose (20.90 g.L-1). Tests were made in defined medium with glucose and xylose and in hydrolysate supplemented with salts and yeast extract. Different concentrations of glucose were tested, namely 10, 15, 20, 30 and 40 g.L-1. The best accumulation results (27.1 % of PHA) were obtained in hydrolysate medium with 10 g.L-1. Using this concentration, assays were performed in fed-batch and sequencing batch reactor conditions in order to determine the best feeding strategy. The strategy that led to the best results was fed-batch assay with 24.7 % of PHA. An assay without sterile conditions was performed, in which was obtained the same growth than in sterilization test. Finally it was performed an assay in a bioreactor and a fast growth (0.14 h-1) with high glucose and xylose consumption rates (0.368 g.L-1.h-1 and 0.0947 g.L-1.h-1, respectively) were obtained. However 1.50 g.L-1 of PHA, corresponding to 16.1 % (92.52 % of 3HB and 3HV of 7.48 %) of % PHA were observed. The polymer was further characterized by DSC with a glass transition temperature of -6.07 °C, a melting temperature of 156.3 °C and a melting enthalpy of 63.07 J.g-1, values that are in accordance with the literature. This work recognizes for the first time the suitability of the pulp paper hydrolysate as a substrate for PHA production by H. mediterranei.