Renewable Power Sources

Of all of the sources of renewable energies available one can argue that the most abundant and accessible are solar power, radiation, and the energy of the tides (70 % of the earth surface is covered by water). The tidal wave energy hasn’t seen a widespread distribution yet, mainly due to the lack of interest of the governments, most of the coastal areas of the world are exclusive responsibility of the governments, thus not easily open for private venture. Considering solar power, there exist two main fields of application, land based systems and space based systems. The former systems are still in a very embryonic phase, with Japan being the lead researcher in the field, with an experimental satellite-power station to be launched before 2010. Land based systems, on the other hand, are well studied, with major research and application programs in all known forms of solar power production. Given a minimum value of incident radiation, and applying the appropriate system, (i.e. power plant type), for any given area the solar power becomes an income-producing industry.

Heavy metals removal in dual media filters

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente – Perfil de Engenharia Sanitária

Valorization of grape pomace through hot compressed water extraction/hydrolysis

The world energy consumption is expected to increase strongly in coming years, because of the emerging economies. Biomass is the only renewable carbon resource that is abundant enough to be used as a source of energy Grape pomace is one of the most abundant agro-industrial residues in the world, being a good biomass resource. The aim of this work is the valorization of grape pomace from white grapes (WWGP) and from red grapes (RWGP), through the extraction of phenolic compounds with antioxidant activity, as well as through the extraction/hydrolysis of carbohydrates, using subcritical water, or hot compressed water (HCW). The main focus of this work is the optimization of the process for WWGP, while for RWGP only one set of parameters were tested. The temperatures used were 170, 190 and 210 °C for WWGP, and 180 °C for RWGP. The water flow rates were 5 and 10 mL/min, and the pressure was always kept at 100 bar. Before performing HCW assays, both residues were characterized, revealing that WWGP is very rich in free sugars (around 40%) essentially glucose and fructose, while RWGP has higher contents of structural sugars, lignin, lipids and protein. For WWGP the best results were achieved at 210 °C and 10 mL/min: higher yield in water soluble compounds (69 wt.%), phenolics extraction (26.2 mg/g) and carbohydrates recovery (49.3 wt.% relative to the existing 57.8%). For RWGP the conditions were not optimized (180 °C and 5 mL/min), and the values of the yield in water soluble compounds (25 wt.%), phenolics extraction (19.5 mg/g) and carbohydrates recovery (11.4 wt.% relative to the existing 33.5%) were much lower. The antioxidant activity of the HCW extracts from each assay was determined, the best result being obtained for WWGP, namely for extracts obtained at 210 °C (EC50=20.8 μg/mL; EC50 = half maximum effective concentration; EC50 = 22.1 μg/mL for RWGP, at 180 ºC).

Bioproduction of succinic acid from renewable feedstocks by Actinobacillus succinogenes 130Z

Succinic acid (SA) is a highly versatile building block that is used in a wide range of industrial applications. The biological production of succinic acid has emerged in the last years as an efficient alternative to the chemical production based on fossil fuels. However, in order to fully replace the competing petro-based chemical process from which it has been produced so far, some challenges remain to be surpassed. In particular, one main obstacle would be to reduce its production costs, mostly associated to the use of refined sugars. The present work is focused on the development of a sustainable and cost-e↵ective microbial production process based on cheap and renewable resources, such as agroindustrial wastes. Hence, glycerol and carob pods were identified as promising feedstocks and used as inexpensive carbon sources for the bioproduction of succinic acid by Actinobacillus succinogenes 130Z, one of the best naturally producing strains. Even though glycerol is a highly available carbon source, as by-product of biodiesel production, its consumption by A. succinogenes is impaired due to a redox imbalance during cell growth. However, the use of an external electron acceptor such as dimethylsulfoxide (DMSO) may improve glycerol metabolism and succinic acid production by this strain. As such, DMSO was tested as a co-substrate for glycerol consumption and concentrations of DMSO between 1 and 4% (v/v) greatly promoted glycerol consumption and SA production by this biocatalyst. Aiming at obtaining higher succinic acid yield and production rate, batch and fed-batch experiments were performed under controlled cultivation conditions. Batch experiments resulted in a succinic acid yield on glycerol of 0.95 g SA/g GLY and a production rate of 2.13 g/L.h, with residual production of acetic and formic acids. In fed-batch experiment, the SA production rate reached 2.31 g/L.h, the highest value reported in the literature for A. succinogenes using glycerol as carbon source. DMSO dramatically improved the conversion of glycerol by A. succinogenes and may be used as a co-substrate, opening new perspectives for the use of glycerol by this biocatalyst. Carob pods, highly available in Portugal as a residue from the locust bean gum industry, contain a significant amount of fermentable sugars such as sucrose, glucose and fructose and were also used as substrate for succinic acid production. Sugar extraction from raw and roasted carobs was optimized varying solid/water ratio and extraction time, maximizing sugar recovery while minimizing the extraction of polyphenols. Kinetic studies of glucose, fructose and sucrose consumption by A. succinogenes as individual carbon sources till 30 g/L were first determined to assess possible metabolic diferences. Results showed no significant diferences related to sugar consumption and SA production between the diferent sugars. Carob pods water extracts were then used as carbon source during controlled batch cultivations. (...)

Fouling of a drinking water system in relation to hydraulic circumstances and customer complaints

In a “perfect” drinking water system, the water quality for the consumers should be the same as the quality of the water leaving the treatment plant. However, some variability along the system can lead to a decrease in water quality (such as discolouration) which is usually reflected in the number of the customer complaints. This change may be related to the amount of sediment in the distribution network, leading to an increase in turbidity at the water supply. Since there is no such thing as a perfect drinking water system, the behaviour of particles in a drinking water network needs a suitable approach in order to understand how it works. Moreover, the combination of measurements, such as turbidity patterns and the Resuspension Potential Method (RPM) aid in the prevention of discoloured water complaints and intervention in the treatment upgrade or the network cleaning. Besides sediments there is also bacterial regrowth in the network, which is related to the water quality and distribution network characteristics. In a theoretical drinking water system higher velocities, temperature and shorter residences times lead to wider bacterial growth. In this study we observe velocity and residence steady-states and bacterial does not seem to be related to either. It can be concluded that adequate measurements of RPM, customer complaints and bacterial concentrations allow a wider knowledge on particle behaviour in drinking water systems.

Water treatments in semi-closed cooling circuits and their impact on the quality of effluents discharged by CERN

Dissertação apresentada à Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia do Ambiente, Gestão de Sistemas Ambientais

Water treatments in semi-closed cooling circuits and their impact on the quality of effluents discharged by CERN

Mestrado integrado em Engenharia do Ambiente, perfil: Gestão de Sistemas Ambientais

Waste recovery into activated carbon for water purification from heavy metals

Dissertação apresentada para obtenção do Grau de Doutor em Engenharia Química Pela Universidade Nova de Lisboa,Faculdade de Ciências e Tecn

Pliocene-quaternary upwelling in the SoutheasternAtlantic may reflect changes in water mass production

Proceedings of tile 1" R.C.A.N.S. Congress, Lisboa, October 1992

Ultrasound velocity profile (UVP) measurements in shallow open-channel flows

1st European IAHR Congress, 6-4 May, Edinburgh, Scotland

Transformation of Medicago truncatula with the arginine decarboxylase gene to modify polyamine metabolism toward water deficit resistance

Dissertation submitted to obtain a Ph.D. (Doutoramento) degree in Biology at the Instituto de Tecnologia Química e Biológica da Universidade Nova de Lisboa

Talk on water ecological economics and participatory watershed governance

Dissertação apresentada para obtenção do Grau de Doutor em Ambiente pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Biochemistry of grape berries: post-genomics approaches to uncover the effects of water deficits on ripening

Dissertation presented to obtain the Ph.D degree in Biochemistry, Plant Physiology

Carbon key-properties for microcystin adsorption in drinking water treatment: structure or surface chemistry?

Dissertação para Obtenção de Grau de Mestre em Engenharia Química e Bioquímica

The effect of water inorganic matrix in ibuprofen adsorption onto activated carbon for water and wastewater treatment

Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica