Dissertations / Theses on the topic 'Wastewater valorization'

La tesi della ha come obiettivo la valorizzazione delle acque di scarto derivanti dalla produzione del bioetanolo da colture cerealicole dedicate. Nella prima parte si studia la produzione di VFA mediante digestione anaerobica. In seguito, sono eseguiti batch tests per valutare la conversione dei VFA in MCFA. Infine, si focalizza sul processo di dowstream per il recupero degli acidi carbossilici dal brodo di fermentazione attraverso reactive extraction e back extraction.

2015 - 2016
The research of new eco-friendly technologies that enable the production of energy is nowadays one of the topics of greatest interest to the scientific community. The population has chosen to break free from the use of fossil fuels, and this leads to the study and development of processes for the production of clean energy starting from biomass. However, at the same time, the concern of the industry is also the disposal and treatment of wastewater. Starting from these considerations, it is advisable to develop processes that, under mild conditions, allow to obtain interesting hydrogen or methane yields. This objective could be achieved through the use advanced oxidation processes (AOPs), such as heterogeneous photocatalysis, photo-Fenton like reaction and photoelectrocatalysis. So, an interesting approach is to explore, in parallel to wastewater treatment, the possibility to produce also an energy source such as hydrogen and/or methane from the degradation of organic substance present in wastewater by AOPs. Considering the characteristic of food industries wastewaters, it is interesting to evaluate the performances of advanced oxidation processes for their treatment aimed to the valorization, through the conversion of specific substances (sugars), in order to obtain compounds with high energetic value, but also for removing substances hardly biodegradable (such as food dyes) that could be present in these industry wastewaters. In this PhD thesis it has been studied the performances of the photocatalytic process for the hydrogen production from food industries wastewaters. In particular, starting from synthetic solution containing glucose, it was evaluated the effect of the presence of noble metals on the semiconductor surface and the effect of the photoactive support (TiO2). Subsequently, providing for the application of heterogeneous photocatalysis to industrial level, the study has been directed to the formulation of a noble metal free photocatalyst with good performances in the production of hydrogen and in the degradation of the sugars present in the solutions. The final formulation was represented by LaFeO3 (a perovskite with semiconducting properties) prepared by combustion flame method. To improve the performances under visible light, LaFeO3 was modified with Ru (Ru-LaFeO3), whose cost is much lower than those of Pd, Pt or Au. Always perspective of the application of the process to industrial level, it was developed a structured photocatalyst for solving the problems related to the photocatalyst separation after the treatment. In particular it was studied the efficiency of magnetic Fe2O3 as support for Ru-LaFeO3. It was also investigated the photoelectrocatalytic process for the hydrogen production, considering the general aspects of the process, the advantages and in particular the attention has been focused on the electrodeposition process for the synthesis of Fe2O3 based photoanodes. Finally, the aim has been the application of the photocatalytic process on a real wastewater coming from the washing process of the fruit (especially cherries). It was not underestimated the presence of food dyes in these types of wastewater. For this reason it was evaluated the efficiency of photo-Fenton process in the removal of several food dyes (such as Red Allura and Tartrazine) using LaFeO3 deposited on corundum monoliths. In addition, it has been evaluated the possibility to couple the photocatalytic process (used for the valorization of the wastewater through the production of hydrogen) to the optimized photo-Fenton system to completely remove the not-biodegradable substances still present in the wastewaters recovered after the photocatalytic treatment using Ru-LaFeO3 supported on magnetic Fe2O3 particles. [edited by author]
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Thesis submitted to obtain the Doctoral degree in Energy and Bioenergy
The main objective of this thesis was to study new valorization routes of ashes produced in combustion and co-combustion processes. Three main valorization pathways were analyzed: (i)production of cement mortars, (ii) production of concretes, and (iii) use as chemical agents to remove contaminants from wastewaters. Firstly, the ashes produced during the mono-combustion of coal, co-combustion of coal and meat and bone meal (MBM), and mono-combustion of MBM were characterized. The aim of this study was to understand the ashes properties in extreme levels of substitution of coal by a residue with a high contamination of specific metals. The substitution of coal by MBM produced ashes with higher content of heavy metals. Secondly, the ashes coming from an industrial power plant working under mono-combustion(coal) and co-combustion conditions (coal+sewage sludge+MBM) were studied. The use of cofuels did not promote significant changes in the chemical and ecotoxicological properties of ashes. Fly ashes were successfully stabilized/solidified in cement mortar, and bottom and circulating ashes were successfully used as raw materials in concrete. The third step involved the characterization and valorization of biomass ashes resulting from the combustion of forestry residues. The highest concentrations of metals/metalloids were found in the lowest particle size fractions of ashes. Biomass ashes successfully substituted cement and natural aggregates in concretes, without compromising their mechanical, chemical, and ecotoxicological properties. Finally, the biomass ashes were tested as chemical agents to remove contaminants from wastewaters. The removal of P, mainly phosphates, and Pb from wastewaters was assayed. Biomass ashes presented a high capacity to remove phosphates. As fly ashes were more efficient in removing phosphates, they were further used to remove Pb from wastewaters. Again, they presented a high efficiency in Pb removal. New potential valorization routes for these ashes are now opened, contributing to improve their valorization rates.
Fundação para a Ciência e a Tecnologia - SFRH/BD/62372/2009 ; European Project “COPOWER

In the Mediterranean area, olive mill wastewater (OMW) and grape pomace (GP) are among the major agro-industrial wastes produced. These two wastes have a high organic load and high phytotoxicity. Thus, their disposal in the environment can lead to negative effects. Second-generation biorefineries are dedicated to the valorization of biowaste by the production of goods from such residual biomasses. This approach can combine bioremediation approaches to the generation of noble molecules, biomaterials and energy. The main aim of this thesis work was to study the anaerobic digestion of OMW and GP under different operational conditions to produce volatile fatti acids (VFAs) (first stage aim) and CH4 (second stage aim). To this end, a packed-bed biofilm reactor (PBBR) was set up to perform the anaerobic acidogenic digestion of the liquid dephenolized stream of OMW (OMWdeph). In parallel, the solid stream of OMW (OMWsolid), previously separated in order to allow the solid phase extraction of polyphenols, was addressed to anaerobic methanogenic digestion to obtain CH4. The latter experiment was performed in 100ml Pyrex bottles which were maintained at different temperatures (55-45-37°C). Together with previous experiments, the anaerobic acidogenic digestion of fermented GP (GPfreshacid) and dephenolized and fermented GP (GPdephacid) was performed in 100ml Pyrex bottles to estimate the concentration of VFAs achievable from each aforementioned GPs. Finally, the same matrices of GP and not pre-treated GP (GPfresh) were digested under anaerobic methanogenic condition to produce CH4. Anaerobic acidogenic and methanogenic digestion processes of GPs lasted about 33 days. Instead, the anaerobic acidogenic and methanogenic digestion process of OMWs lasted about 121 and 60 days, respectively. Each experiment was periodically monitored by analysing volume and composition of produced biogas and VFA concentration. Results showed that VFAs were produced in higher concentrations in GP compared to OMWdeph. The overall concentration of VFAs from GPfreshacid was approximately 39.5 gCOD L-1, 29 gCOD L-1 from GPdephacid, and 8.7 gCOD L-1 from OMWdeph. Concerning the CH4 production, the OMWsolid reached a high biochemical methane potential (BMP) at a thermophilic temperature (55°) than at mesophlic ones (37-45°C). The value reached was about 358.7 mlCH4 gSVsub-1. In contrast, GPfresh got a high BMP but at a mesophilic temperature. The BMP was about 207.3 mlCH4 gSVsub-1, followed by GPfreshacid with about 192.6 mlCH4 gSVsub-1 and lastly GPdephacid with about 102.2 mlCH4 gSVsub-1. In summary, based on the gathered results, GP seems to be a better carbon source for acidogenic and methanogenic microrganism compared to OMW, because higher amount of VFAs and CH4 were produced in AD of GP than OMW. In addition to these products, polyphenols were extracted by means of a solid phase extraction (SPE) procedure by another research group, and VFAs were utilised for biopolymers production, in particular polyhydroxyalkanoates (PHAs), by the same research group in which I was involved.

La forte augmentation de la population mondiale entraîne une demande croissante en eau potable. La production d'eau potable est accompagnée par la génération de résidus du traitement de l'eau dont la boue d'aluminium qui est donc largement disponible mondialement. Ce travail se concentre sur l'identification des différentes voies de valorisation des boues d'aluminium afin de les réutiliser dans le domaine de l’environnement. Deux sources de boues d'aluminium, collectées en France et en Irlande, ont été étudiées dans divers domaines d’application en fonction de leurs caractéristiques. Tout d'abord, les boues d'aluminium ont été utilisées en remplacement d’une partie de l'argile dans la fabrication des briques, en incorporant différents pourcentages de boues d'aluminium et à différentes températures. Les briques résultantes ont été caractérisées et les résultats ont montré que les briques composées de boues d'aluminium et d'argile sont conformes aux « normes européennes et irlandaises » et démontrent ainsi le potentiel pour une application industrielle des boues d'aluminium dans la fabrication de briques en terre cuite irlandaises. Dans un second temps, les boues d’aluminium ont été utilisées comme adsorbant des polluants présents dans l’agriculture. Le glyphosate est un ingrédient actif dans les pesticides utilisés massivement dans l'agriculture irlandaise et représente une problématique environnementale. La boue d’aluminium et la tourbe irlandaise ont été comparées pour l’élimination du glyphosate lors de tests en pot à l’échelle laboratoire. Les résultats ont montré que la boue d’aluminium permet d’éliminer le glyphosate à plus de 99% et réduire les niveaux de DCO. Cet aspect scientifique a permis d’être dans la sélection des adsorbants possibles pour le traitement des eaux usées agricoles en Irlande. Le co-conditionnement et la déshydratation des boues de station d’épuration avec des boues d’aluminium liquides ont également été étudiés. Pour cela, le Jar test a été effectué sur des boues issues d’une station de traitement des eaux française. Les résultats ont montré que le rapport optimal de mélange des boues est de 1:1 (boues d’épuration : boues d’aluminium). Ainsi, la quantité de polymère utilisée peut être diminuée de 14 fois par rapport aux technologies actuelles. Cette approche a permis de montrer la possible valorisation des boues d’aluminium comme un moyen durable et technique permettant ainsi l’élimination des boues localement pour une même station de traitement des eaux. Une autre voie de valorisation des boues d’aluminium comme adsorbant pour la purification des gaz a été étudiée lors d’expériences d’adsorption de H2S dans un réacteur à lit fixe dans différentes conditions expérimentales. Les données expérimentales d’adsorption du H2S ont été modélisées à l'aide de modèles empiriques basés sur la cinétique des processus d'adsorption. Les résultats ont montré que les boues d'aluminium sont un adsorbant efficace pour l'élimination du H2S (capacité de 374,2 mg H2S / g solide) et que des mécanismes mis en jeu sont l'adsorption dissociative et l'oxydation. Les coefficients de transfert de masse globaux ont également été calculés et pouvant ainsi être utilisés pour la prédiction. Enfin, les gâteaux de boues d'aluminium ont été réutilisés pour la purification simultanée d’H2S et le traitement des eaux usées. Les résultats ont montré la capacité de cet adsorbant pour éliminer tout le H2S présent avec une grande efficacité d’élimination de la DCO, TN et TP. Ainsi, il a été démontré la valorisation des boues d’aluminium en tant qu’adsorbant pour une purification du H2S simultanée avec le traitement des eaux usées
The production of drinking water always accompanied by the generation of water treatment residues (WTRs). Alum sludge is one of the WTRs, it is an easily, locally and largely available by-product worldwide. This work focuses on the identification of different ways to valorize the alum sludge for environmentally friendly reuse. Two alum sludges collected from France and Ireland have been reused in various fields as a function of their characteristics. Firstly, alum sludge was used as a partial replacement for clay in brick making, by incorporating different percentages of alum sludge and calcined at different temperatures (range from 800 to 1200 °C). The resultant bricks were tested for compression, Loss on Ignition, water absorption, appearance, etc. Results show that alum sludge-clay bricks have met the “European and Irish Standards” and demonstrated the huge industrial application potential for alum sludge in Irish clay brick manufacturing. Glyphosate is an active ingredient in pesticide which is massive employed in agriculture. Alum sludge and Irish peat were compared for glyphosate removal in pot tests, results show that alum sludge present significant glyphosate removal capacity (>99 %) and could reduce the level of Chemical Oxygen Demand (COD). It provided a scientific clue for sorbents selection when considering the agricultural wastewater treatment in Ireland and to maximize their value in practice. The co-conditioning and dewatering of sewerage sludge with liquid alum sludge was also investigated in Jar-test based on the case analysis of a water industry in France. Results show that the optimal sludge mix ratio is 1:1, the use of the alum sludge has been shown to beneficially enhance the dewaterability of the resultant mixed sludge, and highlighting a huge polymer saving (14 times less than the current technologies) and provided a sustainable and technical sludge disposal route for the local water industry. The use of alum sludge as a sorbent for gas purification was studied by H2S adsorption experiments in a fixed-bed reactor with various operating parameters. The experimental breakthrough data were modeled with empirical models based on adsorption kinetics. Results show that alum sludge is an efficient sorbent for H2S removal (capacity of 374.2 mg/g) and the mechanisms including dissociative adsorption and oxidation were proposed. Moreover, the overall mass transfer coefficients were calculated which could be used for the process scaling up. Finally, alum sludge cakes were reused in the novel aerated alum sludge constructed wetland (CW), which were designed for simultaneous H2S purification and wastewater treatment. Results show that H2S was completely removed in the six months’ trials, while the high removal efficiencies of COD, total nitrogen (TN), total phosphates (TP) were achieved. Thus, a novel eco-friendly CW for simultaneous H2S purification and wastewater treatment was developed. In the different approaches and process considered, in particular it was put in investigating and describing the mechanisms involved. Overall, this work demonstrated alum sludge could be a promising by- product for various novel beneficial reuse rather than landfilling and provided a “Circular Economy” approach for WTRs management

Development of livestock farming sector poses serious concerns on its environmental impact due to the production of huge volume of slurries characterized by high concentrations of organic and mineral pollutants, mainly in the form of ammonia, phosphates and carbon compounds. The aim of this work was to evaluate the possibility to use microalgae as a biological tool for the depuration of such wastewaters, assimilating the nutrients and producing an added value biomass to be used in different sectors such as the food and feed, nutraceutical and bioenergy. Chapter 1 deals with the study of a digestate treatment plant characterized by a series of physical-chemical treatments which depurate the liquid fraction of the digestate through membrane technology (ultrafiltration and reverse osmosis) allowing to discharge 50% of the slurry as clean water and to produce ammonium sulfate and nutrients-rich solids/concentrates usable as fertilizers. The ultrafiltration step produces also a clear permeate still rich in soluble nutrients that could be further used as a growth medium for microalgae production. Chapter 2 intended to demonstrate the possibility to integrate microalgae production with this system, helping to reduce the cost of slurry treatment and improving the energy balance of the process. The tolerance of the microalga Scenedesmus sp. to the permeate was evaluated, results demonstrating that percentage upper than 10% inhibited the growth of this microalga, but below this value productivity up to 124 mg L-1 d-1 could be obtained. The composition of the culture medium also influenced the biomass composition, with protein, carbohydrate and lipid content being a direct function of ammonia concentrations. It was then demonstrated that integrating microalgae production with anaerobic digestion it is possible to produce 166-190 t y-1 of microalgal valuable biomass. Chapter 3 focused on the possibility to exploit a wild microalga strain (Chlorella sp.), isolated in the farm, to improve the depuration of the digestate and the two digestate liquid fraction after centrifugation and ultrafiltration. The results demonstrated that digestate could not support a good growth, as the other two liquid stream, because of low light availability in the culture. Ultrafiltrate, on the other hand, resulted in the best biomass productivity (0.21 g L-1d-1) comparable to that obtained in a synthetic medium. All the streams were depurated with ammonia, phosphorus and COD reduction up to 98%, 99% and 70% respectively Besides these encouraging data it has been found that only 30% of the nitrogen were successfully incorporated in the microalgal biomass due to stripping processes, posing serious environmental concerns on the process In Chapter 4 astaxanthin-producer Haematococcus pluvialis was cultivated in a treated swine slurry with low-cost cascade filters. Although this microalga is slow-growing and very susceptible to contamination, it showed a sustained growth (up to 60 mg L-1 d-1 of biomass) in the waste stream reducing all the pollutants present in the wastewater. Moreover it accumulated a good amount of astaxanthin, improving the overall feasibility and sustainability of the process.

Dissertation for PhD degree in Bioengineering
Oil and gas industry are responsible for the generation of large volumes of hydrocarbon-contaminated wastewaters. In order to minimize its negative impact on the environment and public health, strict regulations were developed for its treatment and discharge into the sea, leading to a search for innovative and more sustainable strategies for its management. The aim of this thesis is to explore the feasibility of a biological process for the treatment of mineral oil wastewaters coupled with its valorization towards the production of added-value compounds. The efficient treatment of saline oilfield PW, generated during petroleum extraction process, and lubricant-based wastewater (LW) coupled with neutral lipid production by Alcanivorax borkumensis SK2 and Rhodococcus opacus B4 was demonstrated in a sequencing batch airlift reactor (SBAR). Different operational conditions (e.g. cycle duration and carbon/nitrogen ratio (Total petroleum hydrocarbons (TPH)/N)) were tested in order to optimize the treatment efficiency, 96 % and 80 % of TPH removal efficiencies in SBARAb+PW and SBARR.o+LW, respectively, and maximize lipids accumulation (85 % and 94 % of the cellular dry weight (CDW) in SBARAb+PW and SBARR.o+LW, respectively). The nitrogen availability (low TPH/N ratios) influenced the production of TAGs and WEs by A. borkumensis SK2, while the carbon source concentration (high TPH/N ratios) was determinant for the accumulation of TAGs by R. opacus B4. Furthermore, the effect of oxygen concentration on the treatment of PW in a SBAR operation was evaluated. The selection of the oxygen concentration applied allowed to direct A. borkumensis SK2 metabolism to a particular type of storage compound (TAGs, WEs or polyhydroxyalkanoates (PHAs)) maintaining a TPH removal efficiency of 90 - 95%. A. borkumensis SK2 produced a cell-bound and an extracellular biosurfactant in order to increase hydrocarbons availability and up-take, showing that PW valorization towards the production of surface-active compounds is possible. Finally, the efficient treatment of saline oilfield PW (90 - 92 % of TPH removal efficiencies) and neutral lipids production by A. borkumensis SK2 in a continuous airlift operation was shown. Was observed that the TPH/N ratio applied to the bioreactor did not influence hydrocarbons biodegradation and intracellular lipid accumulation, however an improvement on WEs and TAGs excretion was observed when lower TPH/N ratios were applied.
A indústria petrolífera é responsável pela produção de grandes volumes de águas residuais contaminadas com hidrocarbonetos. De forma a minimizar os impactos negativos no ambiente e na saúde pública, foram desenvolvidas regulamentações restritas para o seu tratamento e descarga, fomentando a procura por estratégias inovadoras e mais sustentáveis para a sua gestão. O objetivo desta tese é explorar a viabilidade de um processo biológico para o tratamento de águas residuais contaminadas com hidrocarbonetos, bem como a sua valorização para produção de compostos de valor acrescentado. O tratamento eficiente de água de produção (PW), gerada no processo de extração de petróleo, e água residual contaminada com lubrificantes (LW) acoplado com a produção de lípidos neutros por Alcanivorax borkumensis SK2 e Rhodococcus opacus B4 foi demonstrado num SBAR. Diferentes condições operacionais (duração dos ciclos e razão carbono/azoto (Hidrocarbonetos totais de petróleo (TPH) /N)) foram testadas de forma a otimizar a eficiência do tratamento (96 % remoção de TPH no SBARAb+PW e 80 % no SBARR.o+LW) e maximizar a acumulação de lípidos (85 % e 94 % do peso seco celular em SBARAb+PW e SBARR.o+LW, respetivamente). A disponibilidade de azoto (razões TPH/N baixas) influenciou a produção de triacilgliceróis (TAGs) e ésteres de ceras (WEs) pela A. borkumensis SK2, enquanto que a concentração da fonte de carbono (elevadas razões TPH/N) foi determinante para a acumulação de TAGs por R. opacus B4. Posteriormente, foi avaliado o efeito da concentração de oxigénio no tratamento de PW numa operação SBAR. A manipulação da concentração de oxigénio fornecido, permitiu direcionar o metabolismo de A. borkumensis SK2 para um tipo particular de composto de reserva (TAGs, WEs ou polihidroxialcanoatos (PHA)), mantendo uma eficiência de remoção de TPH de 90 - 95%. A. borkumensis SK2 produziu um biosurfactante extracelular e um ligado à parede celular, de forma a aumentar a disponibilidade e absorção de hidrocarbonetos, demonstrando que é possível a valorização da PW para a produção de compostos tensioativos. Finalmente, o tratamento eficiente de PW (90 - 92 % eficiências de remoção de TPH) e produção de lípidos neutros por A. borkumensis SK2 foi demonstrado num airlift operado em modo contínuo. Foi observado que a razão TPH/N aplicada ao reator não influenciou a biodegradação de hidrocarbonetos nem a acumulação de lípidos intracelulares, contudo a excreção de TAGs e WEs foi melhorada quando razões TPH/N mais baixas foram aplicadas.
The work presented in this thesis was financially supported by a PhD grant (SFRH/BD/116154/2016) from Portuguese Foundation for Science and Technology (FCT I.P.) and European Social Fund (EU-ESF, Portugal 2020, POR-NORTE); and project SaltOil+ (POCI-01-0145- FEDER-030180) (Portugal 2020, COMPETE 2020) financed by FCT I.P. and the European Regional Development Fund (ERDF).

Dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
An unprecedented demographic explosion occurred in the last decades at a global level. The negative impacts of this event stand out, affecting the social, economic and mainly environmental spheres. In the environmental aspect, an important consequence is the growing production of solid wastes, due partially to the population increase. However, the development of effective technologies for the treatment of these wastes did not accompany such growth, and currently the most used method for this is landfill disposal. Even with the possibility of alternatives, the use of landfills for the disposal of solid wastes will be necessary over a long period, with the inevitable consequence of the generation of leachate streams. The objective of this work is the development, design and implementation of processes for physicochemical conversion of leachate liquid effluents from a composting process in liquid fertilizers with a standardized and reproducible composition. The leachate sample was collected in February 2019 from the slurry storage tank of the company “Resíduos do Nordeste”, EIM (Urjais, Mirandela, Portugal). The stream is produced and recovered from a composting line from a mechanical and biological waste treatment plant. From this original sample, three additional materials were obtained: a filtered sample for the removal of the solid fraction (Filtro 03/04), two concentrated samples by simple distillation, with two concentration levels in volume basis: 1,19x and 1,85x in relation to the original leachate sample. The four samples (the original leachate and the three processed samples) were submitted to a sequence of analyzes, in order to compare its composition and properties with the current Portuguese and European legislation specifications for liquid fertilizers. The selected characterization parameters were: Total Organic Carbon (TOC), pH, Conductivity, Percentage of Dry Matter, Density, and Heavy Metals, Phosphorus, Potassium and Nitrogen contents. Adsorption tests were performed with the Filter 03/04 sample, with two adsorbents of different origin, the first produced from an organic compound, resulting from a centralized composting process, obtained from the same landfill that provided the Original sample. The second adsorbent tested is activated clays, originating from four different deposits in Kazakhstan. After treatment with the adsorbents, the same analyzes were performed previously, aiming to evaluate the efficiency of the adsorbents. The characterization results were then used to verify the framework for later use of the original leachate and/or the processed samples as liquid organomineral fertilizers, and to assess the specific needs of composition tuning for the non-processed leachate sample. A concentration process for the original sample of 1,19x (v/v) has been determined to allow the reaching of at least 3% TOC, a content legally required. Additionally, treatment is required for the removal of nickel and chromium from the samples. The metals zinc, copper, cadmium and lead have been quantified and are within the limits specified in the Regulation of the European Parliament and of the Council (2019). A flowchart for the proper treatment of this leachate was proposed, with the intention of using it as liquid organomineral fertilizer.
Uma explosão demográfica sem precedentes ocorreu nas últimas décadas a nível global. Destacam-se os impactos negativos deste evento, afetando as esferas social, econômica e principalmente ambiental. No aspeto ambiental, uma consequência importante é a crescente produção de resíduos sólidos, em parte devido ao aumento populacional. No entanto, o desenvolvimento de tecnologias eficazes para o tratamento desses resíduos não acompanhou esse crescimento, e atualmente o método mais utilizado para isso é o descarte em aterros sanitários. Mesmo com a possibilidade de alternativas, o uso de aterros sanitários para a disposição de resíduos sólidos será necessário por um longo período, com a inevitável consequência da geração de caudais de chorume. O objetivo deste trabalho é o desenvolvimento, proposta e implementação de processos de conversão físico-química de efluentes líquidos lixiviados, de um processo de compostagem, em fertilizantes líquidos com uma composição padronizada e reprodutível. A amostra de lixiviados foi coletada em fevereiro de 2019 a partir do tanque de armazenamento de chorume da empresa “Resíduos do Nordeste”, EIM (Urjais, Mirandela, Portugal). O fluxo é produzido e recuperado de uma linha de compostagem de uma estação de tratamento de resíduos mecânica e biológica. Desta amostra original, três materiais adicionais foram obtidos: uma amostra filtrada para a remoção da fração sólida (Filtro 03/04), duas amostras concentradas por destilação simples, com dois níveis de concentração em base volumétrica: 1,19x e 1,85x em relação a amostra original. As quatro amostras (o lixiviado original e as três amostras processadas) foram submetidas a uma sequência de análises, de modo a comparar a sua composição e propriedades com as atuais especificações da legislação portuguesa e europeia para fertilizantes líquidos. Os parâmetros de caracterização selecionados foram: teor de carbono orgânico total (TOC), pH, condutividade elétrica, percentagem de matéria seca, densidade e metais pesados, fósforo, potássio e nitrogênio. Foram realizados testes de adsorção com a amostra Filtro 03/04, com dois adsorventes de origem diferente, o primeiro produzido a partir de um composto orgânico, resultante de um processo de compostagem centralizada, obtido do mesmo aterro sanitário que forneceu a amostra Original. O segundo adsorvente testado, são as argilas ativadas, originárias de quatro depósitos diferentes do Cazaquistão. Após o tratamento com os adsorventes foram realizadas as mesmas análises feitas anteriormente, com o objetivo de avaliar a eficiência dos adsorventes. Os resultados da caracterização foram então utilizados para verificar a estrutura para posterior utilização do lixiviado original e/ou as amostras processadas como fertilizantes organominerais líquidos, e para avaliar as necessidades específicas de ajuste da composição. Um processo de concentração para a amostra original de 1,19x (v/v) foi determinado para permitir o alcance de pelo menos 3% de TOC, um conteúdo legalmente requerido no Regulamento do Parlamento Europeu e do Concelho (2019). Além disso, é necessário um tratamento para a remoção de níquel e cromio das amostras. Os metais zinco, cobre, cádmio e chumbo foram quantificados e estão dentro dos limites especificados no Regulamento do Parlamento Europeu e do Conselho (2019). Um fluxograma para o tratamento adequado desse lixiviado foi proposto, com o intuito de utilizá-lo como fertilizante organomineral líquido.
This work was carried out under the scope of Project VALORCOMP, funded by FEDER through Programme INTERREG V-A Spain − Portugal (POCTEP) 2014–2020. Finally, to all who have somehow been part of this period and collaborated to carry out this work, I will be eternally grateful.

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
With the exponential increase of the world population over the years, the organic waste generated from coffee also increased, since it is one of the most consumed commodities of world. Nowadays, many research studies aim to reduce or avoid environmental impacts. One way is the valorization of solid waste into high-added value products, as is the case of the preparation of activated carbons from raw biomass. Due to their well-developed porosity, activated carbons can be used to remove pollutants contained in wastewater effluents through adsorption processes. The main objective of this work is the development of activated carbons from coffee husks, considering HNO3 and KOH as activation agents, and their assessment in the removal of 2-nitrophenol and 4-nitrophenol, selected as target pollutants. The activating agents were used at different concentrations (1 and 5 mol L-1) and the precursor was activated for 3 hours at 60 °C. Then, the resultant materials were carbonized by pyrolysis at 800 °C under continuous flow of N2. The activated carbons were used to adsorb 2-nitrophenol and 4-nitrophenol at 25 °C and pH 6.0. Upon analysis of the adsorption isotherms obtained, it was possible to conclude that the activated carbon that leads to a high percentage of pollutant removal was the one activated with KOH 5 mol L-1, considering an initial concentration of 25 mg L-1 of 2-nitrophenol and 50 mg L-1 of 4-nitrophenol with a concentration of adsorbent of 2.5 gads L-1. This activated carbon, prepared with a low burn-off, had 92.9% (9.7 mg2-NP gads-1) of removal of 2-nitrophenol and 97.7% (22.5 mg4-NP gads-1) of removal of 4-nitrophenol. It had 84.1% of burn-off in its development process. Due to the superior results of this material, the kinetic analysis was done using only the activated carbon activated with KOH 5 mol L-1. The kinetic results show that the material reached its maximum adsorption after 4 h adsorbing around 85% of both pollutants. The modelling of the kinetic results was also done. The best model to predict in a representative way the adsorption isotherm was the Freundlich model for both pollutants. For the adsorption kinetic model, the best fittings were obtained with the Bangham model for 2-nitrophenol adsorption and with the pseudo-second-order model for 4-nitrophenol adsorption.
Com o aumento exponencial da população mundial ao longo dos anos, os resíduos orgânicos gerados a partir do café aumentaram também, uma vez que é um dos bens mais consumidos no mundo. Atualmente, muitas pesquisas têm como objetivo reduzir ou evitar impactos ambientais. Uma das alternativas estudadas consiste na valorização de resíduos sólidos em produtos de alto valor agregado, como é o caso da preparação de carvões ativados a partir de biomassa bruta. Devido à sua porosidade, os carvões ativados podem ser usados para remover os poluentes contidos em águas residuais através do processo de adsorção. O principal objetivo deste trabalho é o desenvolvimento de carvões ativados a partir de casca de café, usando HNO3 e KOH como agentes de ativação, e sua avaliação na remoção de 2-nitrofenol e 4-nitrofenol, selecionados como poluentes modelo. Os agentes ativadores foram utilizados em diferentes concentrações (1 e 5 mol L-1) e o precursor foi ativado durante 3 horas a 60 °C. Em seguida, os materiais resultantes foram carbonizados por pirólise a 800 °C sob fluxo contínuo de N2. Os carvões ativados foram utilizados para adsorver 2-nitrofenol e 4-nitrofenol a 25 °C e pH 6.0. Através da análise das isotérmicas de adsorção obtidas, foi possível concluir que o carvão ativado que remove maior percentagem de poluentes é aquele ativado com KOH 5 mol L-1, considerando uma concentração inicial de 25 mg L-1 de 2-nitrofenol e 50 mg L-1 de 4-nitrofenol. Esse carvão ativado, que apresenta um baixo valor de burn-off, teve 92,9% (9,7 mg2-NP gads-1) de remoção de 2-nitrofenol e 97,7% (22,5 mg4-NP gads-1) de remoção de 4-nitrofenol com concentração de adsorvente de 2.5 gads L-1. Teve 84,1% de burn-off em seu processo de desenvolvimento. Tendo em consideração o seu melhor desempenho, os estudos cinéticos foram realizados utilizando apenas o carvão ativado que foi ativado com KOH 5 mol L-1. Os resultados cinéticos mostraram que o material atingiu a sua adsorção máxima após 4 h, adsorvendo cerca de 85% dos dois poluentes. A modelação dos resultados cinéticos foi também realizada. O melhor modelo para prever de forma representativa a isotérmica de adsorção para ambos os poluentes foi o modelo de Freundlich. Para o modelo cinético de adsorção, os melhores ajustes foram obtidos com o modelo de Bangham para adsorção de 2-nitrofenol e com o modelo de pseudo-segunda ordem para adsorção de 4-nitrofenol.

Dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
The municipal organic waste is typically treated by mechanical separation and then by anaerobic digestion and composting, in order to valorise the residues in a biogas stream for energy purpose and in compost that can be used in agriculture. However, the current waste management legislation in Europe and the expected developments on the coming directives regarding the application of the “end-of-waste” criteria, are leading to barriers on the use of fertilizers resulting from waste. The current work proposes an alternative strategy to the valorisation of compost through the production of low-cost materials to be used as catalysts in the treatment of wastewaters. The compost was supplied by a waste management company located in the North Est region of Portugal, and then subjected to thermal and hydrothermal treatments. Compost was mixed with water, filtered and washed in order to remove the soluble compounds and suspended solids. Then, materials were prepared with H2SO4 (18 M) and different mass ratios of glycerol, the resulting products of reaction being calcined at 800 ºC. The material that presented the highest conversion was washed with hydrogen peroxide (H2O2), at room temperature and at 60 ºC, and HCl (1 M). The prepared materials were sieved, and the samples obtained were tested in H2O2 decomposition and in the remediation of waters containing one model pollutant with lipophilic character (4-nitrophenol) by catalytic wet peroxide oxidation (CWPO). The effluents of the CWPO and H2O2 decomposition runs were analysed in order to quantify the pollutant, oxidant, TOC and the leached iron. In this sense, it was concluded that the materials produced shows activity through the analyses, and the conversions reached had a strong contribution of leached iron. Then, the amount of leached iron could be minimized while maintaining the conversions.
Atualmente, os resíduos orgânicos urbanos são tipicamente separados e tratados por digestão anaeróbia e compostagem, permitindo a sua valorização em biogás, para fins energéticos, e a produção de composto, usado na agricultura como fertilizante. No entanto, a legislação europeia em matéria de gestão de resíduos, e os desenvolvimentos esperados nas próximas diretivas sobre a aplicação dos critérios relativos a “fim do resíduo”, estão a limitar o uso de fertilizantes procedentes de resíduos. O presente trabalho propõe uma estratégia para a valorização de composto, convertendo-o em materiais de baixo custo capazes de serem utilizados como catalisadores em reações de oxidação no tratamento de águas resíduais. O composto utilizado neste trabalho foi fornecido por uma empresa de gestão de resíduos localizada em Trás-os-Montes, sendo de seguida sujeito a tratamentos térmicos e hidrotérmicos. O material de partida foi misturado com água, filtrado e lavado para remover parte do conteúdo solúvel e os sólidos suspensos. Em seguida foram produzidos materiais por tratamento com H2SO4 (18 M) e diferentes razões mássicas de glicerol. O material resultante da reação foi submetido a calcinação a uma temperatura de 800 ºC. Destes materiais preparados, o que apresentou maior conversão, foi lavado com peróxido de hidrogénio, a temperatura ambiente e a 60 ºC, e HCl (1 M). Os materiais preparados foram testados na decomposição catalítica de H2O2 e na remediação de águas contaminadas com um poluente modelo de caráter lipofílico (4-nitrofenol), por oxidação catalítica com peróxido de hidrogénio (CWPO). Ao final da decomposição catalítica e CWPO foi feita análise para determinação de ferro lixiviado e análise de carbono orgânico total (TOC). Conclui-se que os materiais produzidos apresentam atividade através das análises feitas, sendo que as conversões alcançadas tiveram forte contribuição do ferro lixiviado. Foi possível de seguida minimizar-se a quantidade de ferro lixiviado mantendo as conversões.
To VALORCOMP and LSRE-CM for the opportunity to be and the knowledge acquired during this work, for sure is very important to my professional life.

The urge for more sustainable wastewater treatment solutions based on the well-established concept of “circular economy” is progressively paving the way towards new resource recovery-oriented strategies. A paradigm shift has been driven conceiving wastewater treatment plants (WWTPs) as collection points of resources (e.g., nutrient, water, energy, etc.): their redesign from treatment facilities into water resource recovery factories (WRRFs) is considered able to provide multiple opportunities to contribute to a more circular economy-based water sector. The resource recovery potential is particularly emphasized in the case of granular sludge (GS)-based technologies that were recognized as viable alternative to conventional activated sludge (CAS) systems for a wide range of biological wastewater treatment processes. Biogranulation consists in forcing microrganisms to form granules (i.e., self-aggregated biofilms without the presence of carrier materials) rather than flocs: the compact granular form endows excellent settleability, easier solid/liquid separation, and enhanced biomass retention. As in conventional biofilms, in granules microorganisms are embedded in a matrix of highly hydrated Extracellular Polymeric Substances (EPS) secreted by bacterial consortia during cell metabolism. The complex and diverse biopolymeric matrix mainly consists of proteins (PN), polysaccharides (PS), uronic acids, lipids, nucleic acids, humic-like substances, etc. EPS contribute to the initial aggregation of microbial cells and are mainly associated with the structural integrity, rheological behaviour, physic-chemical properties, and functional stability of granules. Hence, EPS exert multiple functions within the granular biofilm such as protection, nutrient source, maintenance of a stable structure, and organic substance sorption. The recovery and conversion of EPS into bio-based commodities is considered an appealing route to enhance the economics and sustainability of wastewater treatment according to a circular economy pattern in waste sludge management. Thanks to their versatile properties, GS-derived EPS can be valorized in multiple industrial/environmental solutions alternatively to synthetic polymers (e.g., coating/sizing agents in paper and textile industry, cement curing, biosorption, etc.), thus contributing to a less fossil-fuel dependent manufacturing sector. The development of EPS recovery-oriented solutions is currently hampered by many bottlenecks which can be mainly identified in a still incomplete understanding of various fundamental aspects in terms of both EPS composition/properties and production regulation. Further research effort is therefore demanded to progress towards the sustainable EPS recovery and conversion into value-added biomaterials able to generate a change in the critical status of waste sludge management in WWTPs. In this perspective, the present thesis mainly aimed to give insights on the recovery, characterization, and valorization of Extracellular Polymeric Substance (EPS) from waste granular sludge of different origin. Particular emphasis was dedicated on potential approaches to move towards the production of EPS-based biomaterials to be valorized in environment-related applications. Particularly, two types of GS were investigated (aerobic granular sludge, AGS, and anammox granular sludge, AmxGS) and distinct resource recovery-oriented scenarios were addressed depending on the nature of the studied microbial aggregates. Various solutions to engineer the most attractive features of these waste-derived biopolymers were hence proposed and all the evaluation criteria and methodologies were consequently adapted: hydrogel-based materials with great potential in sustainable agronomic practises (AGS-recovered EPS) and biosorbent media for the treatment of heavy metal-contaminated wastewaters (AmxGS-recovered EPS). More detailed, the thesis structure, methodologies and main findings can be summarized as follows. Chapter 1 introduces the general background of the thesis. The urge for more sustainable wastewater treatment solutions based on the concepts of “resource recovery” and “circular economy” was emphasized. The attractiveness of GS-based technologies as viable alternative to conventional activated sludge systems was presented: particularly, their potential in terms of EPS production/recovery was pointed out. The main bottlenecks limiting the large-scale implementation of EPS-based biomaterials have been comprehensively discussed. Finally, the outlines and main goals of the thesis are presented. Chapter 2 proposes a comprehensive analysis of the hydrogel-forming ability and resulting post-gelling mechanical properties of structural extracellular polymeric substances (sEPS) extracted from aerobic granular sludge (AGS). The gelling protocols in presence of divalent metal cations (e.g., Ca2+) were adapted with the aim to minimize the polymer consumption and optimize the hydrogel geometry for the analytical investigation. The high-complexity and diversity of AGS-derived sEPS was addressed by evaluating the overall process of hydrogel-formation in comparison with well-known biopolymers (i.e., alginate and k-/ι-carrageenan). The post-gelling mechanical behaviour was evaluated under both compression and shear stress conditions via rheometry. Particularly, sensitive parameters were extrapolated from the observed mechanical profiles (e.g., Young’s modulus, E, storage modulus, G’, loss modulus, G’’, complex viscosity, η*) and correlated with the applied gelling conditions to gain insights on the main drivers of the hydrogel-formation processes. Based on the results emerged from the mechanical characterization, the minimum sEPS (weight) concentration enabling the formation of an extended cross-linked polymeric network was recognized in the range of 2.5 – 5 wt% (for sEPS concentrations lower than 2.5 wt% only weakly interconnected polymeric clusters were probably present). The higher polymer and (ionic) cross-linker concentrations needed for the sEPS hydrogel-formation with respect to the studied reference polymers gave hence a proof-of-principle of the greater complexity and diversity of the sEPS matrix (likely involving also compounds not really contributing to the gelling processes and resulting post-gelling mechanics). Distinct mechanical responses to consecutive compression-decompression cycles were observed among the studied biopolymer-based hydrogels. Particularly, sEPS and ι-carrageenan hydrogels behaved similarly under mechanical stresses: their linear elastic behaviour was preserved along the subsequent loading-unloading cycles, but lower levels of stiffness were achieved compared to alginate and k-carrageenan-based systems. For all the studied biopolymers, the post-gelling stiffness varied significantly depending on the applied hydrogel-forming conditions, even if the overall mechanical response remained almost unchanged: E increased upon increasing the polymer and (ionic) cross-linker concentration and varied based on the (divalent) metal cation used as cross-linking agent. The oscillatory shear measurements confirmed that sEPS were able to form hydrogels with solid-like mechanical properties. From an applicative point of view, the feasibility of forming sEPS-based hydrogels with mechanical properties comparable to other biopolymer-based systems currently applied for commercial purposes was presented, thus suggesting potential resource recovery-oriented solutions able to progress towards a less fossil fuel-dependent manufacturing sector. Chapter 3 offers a consistent approach to engineer the hydrogel-forming properties of AGS-derived sEPS based on the high qualitative standards imposed by the agronomic sector. Particularly, the influence of various chemicals in the extraction and gelling processes on the quantity/quality of the extractable EPS macromolecules was pointed out, emphasizing the importance to adapt the methodologies on the research objectives. With this regard, extraction and gelling protocols widely discussed in literature were adapted providing chemical reagents containing no sodium or chlorine which are considered phytotoxic in large quantities: K2CO3 or (NH4)2CO3/HNO3/KOH (extraction) and Ca(NO3)2∙H2O or Ca(C2H5COO)2 (cross-linking). The quality/quantity of the extractable EPS macromolecules as well as their overall hydrogel-forming ability did not appear strongly influenced by the distinct chemicals applied. Conversely, more significant differences were observed in terms of compositional analysis (e.g., macronutrients, Na, Cl, heavy metals, etc.). Overall, the obtained sEPS and derived biomaterials (e.g., hydrogels) were consistent with the current environmental legislation in matter of soil improvers and fertilizing products, resulting within the maximum limits imposed in terms of heavy metals (values related to Cr(VI) to be investigated). The great potential of the obtained sEPS hydrogels in agronomy-oriented solutions was emphasized evaluating their swelling ability and nutrient release capacity. Particularly, the behaviour of sEPS-based hydrogels as superabsorbent polymers (SAPs) able to sorb and hold high quantities of water (up to 16 g H2O per g hydrogel as dry matter) was suggested. Moreover, a preliminary proof-of-principle of the potential application of sEPS hydrogels as carrier systems for nutrient loading and release was given. The biodegradability assessment was preliminarily carried out by adapting respirometric techniques (single- and multiple-OUR experiments): conclusions in terms of organic matter biodegradability were drawn based on the partitioning of the sample Chemical Oxygen Demand (COD) in soluble biodegradable, particulate biodegradable, soluble inert and particulate inert fractions. It has been found that sEPS and derived hydrogels can be utilized as substrate from the microbial communities inhabiting the activated sludge, but their biodegradation was influenced by the chemicals applied in the extraction and gelling processes. Moreover, it has been observed that the readily biodegradable carbonaceous fraction decreased upon hydrogel-formation: the establishment of an extended 3D polymeric network in which the sEPS macromolecules were more confined likely resulted in a decreased substrate accessibility, thus requiring further hydrolytic reactions before their microbial utilization. Finally, guidelines to progress towards new resource recovery-oriented solutions in agriculture exploiting the versatile properties of AGS-derived sEPS were proposed. Chapter 4 deals with the feasibility of exploiting EPS extracted from waste anammox granular sludge (AmxGS) in high-performance and cost-effective technologies for the treatment of heavy metal-contaminated wastewater. With this regard, the metal-binding ability of the recovered EPS was addressed in comparison to that of pristine granules in single- and multi-metal biosorption studies mainly to shed light on the biosorption mechanisms of extracted and non-extracted EPS in native biomass. Metal-binding capacities equivalent or higher than conventional and/or unconventional sorbent media were found both for extracted EPS and pristine anammox granules, but distinct biosorption pathways were suggested. These differences could be due to three main reasons: (i) multiple mechanisms participating in the heavy metal biosorption by native granules, in addition to the heavy metal uptake by EPS; (ii) EPS chemical modifications induced by the extraction method applied; (iii) different polymer chain mobility and binding site availability of extracted EPS in aqueous dispersions and non-extracted EPS in pristine granules. Mechanistic hypothesis on metal biosorption were suggested: as emerged from a detail molecular-level analysis carried out combining various analytical techniques, a multifaceted mechanism based on a combination of electrostatic interaction, ion exchange, complexation and precipitation has been proposed. Particularly, it has been found that AmxGS-extracted EPS behaved like flocculant/complexing agents in presence of high-concentrated heavy metal-contaminated aqueous systems, leading to the spontaneous precipitation of EPS-metal composite aggregate. Finally, a proof-of-principle of the potential application of the extracted EPS in composite sorbent media (e.g., with activated carbon) able to target single and multiple heavy metals simultaneously from contaminated aqueous systems was given, thus suggesting encouraging strategies to enhance the industrial applicability of AmxGS-derived EPS. Chapter 5 draws the general conclusions and outlooks of the thesis, thus suggesting the next challenges to be addressed in follow up research. The outstanding potential of both AGS- and AmxGS-derived EPS in environment-related applications has been emphasized, thus shedding light on recourse recovery-oriented solutions able to progress towards a more circular economy-based water sector.

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná
The discharge of industrial and domestic wastewater is one of the main causes of contamination of water bodies by heavy metals. Among these heavy metals, nickel (Ni) is one of the most used in industrial processes, such as the production of alloys, stainless steel and automotive batteries, as well as electroplating activities, causing high concentrations in the effluents of these industries. Several techniques, such as chemical precipitation and filtration, have been studied in order to promote the removal of these heavy metals from wastewater. However, these techniques are often financially and technically costly. Under this context, adsorption using activated carbons (ACs) appears as an alternative, which is characterized by being an effective and economically viable technique. Citrus fruits, such as tangerine, are of great importance in the Portuguese economic context. In 2017, just over 374.4 thousand tons were produced, with 10% of this volume corresponding to tangerine. This research aimed, therefore, to produce ACs from tangerine peels and use them in the adsorption of nickel from aqueous medium. The ACs were produced in two stages: activation and carbonization. Upon activation, the hydrothermal carbonization process (HTC) was used considering FeCl3 as activating agent under three concentrations (0.5, 1.0 and 2.5 M). Afterwards, the prepared materials were carbonized in a tubular oven at 800 ºC for 4 h. The samples were named as follows: TW-C (pyrolyzed peels without HTC), TW-Fe-0.5-C / TW-Fe-1.0-C / TW-Fe-2.5-C (HTC and pyrolyzed peels) and TW-Fe-2.5 (peels with HTC without pyrolysis). The physico-chemical properties of the ACs, such as elemental analysis, ash content, acidity and basicity, were determined to correlate with their performance. The kinetic and isotherm adsorption of Ni(II) onto the ACs was assessed at the following operating conditions: 2.5 g L-1 of AC, 25 ºC and pH 6 and modelled by the kinetic models of pseudo-first order, pseudo-second order and Elovich, as well as the adsorption isotherms of Langmuir, Freundlich and the General Isotherm Equation (GIE) of Tóth. The materials TW-C showed the best adsorption results and removed 99% of Ni(II) at pH 9. The kinetic models that best described the adsorption process were pseudo-second order (TW-Fe-2.5-C) and Elovich (TW-C). The GIE of Tóth showed the best fit, however, its parameters did not show statistical significance at the 5% confidence level, being rejected. The Freundlich model was able to represent the experimental data with certain precision (R² reached 0.9557 and 0.9785 for TW-C and TW-Fe-2.5-C, respectively) and statistical significance according to the t-test and F-test.
A descarga de águas residuais industriais e domésticas é uma das principais causas de contaminação de corpos d'água por metais pesados. Entre esses metais pesados, o níquel (Ni) é um dos mais utilizados em processos industriais, como na produção de ligas metálicas, aço inoxidável e baterias de automóveis, bem como na galvanoplastia, originando altas concentrações nos efluentes dessas indústrias. Várias técnicas, como precipitação química e filtração, foram estudadas para promover a remoção desses metais pesados de águas residuais. No entanto, essas técnicas são financeiramente e tecnicamente caras. Como alternativa surge a adsorção utilizando carvão ativado (AC), caracterizada por ser uma técnica eficaz e economicamente viável. Os citrinos, como a tangerina, apresentam relevada importância no contexto económico português. No ano de 2017 foram produzidas pouco mais de 374,4 mil toneladas, onde 10% desse volume correspondeu a tangerina. Tendo este enquadramento em consideração, este trabalho objetivou produzir ACs a partir de cascas de tangerina para aplicação na adsorção de níquel presente em meio aquoso. Os ACs foram produzidos em duas etapas: Ativação e Carbonização. Na ativação foi usado o processo de carbonização hidrotérmica (HTC) considerando FeCl3 como agente ativante em três concentrações (0,5; 1,0 e 2,5 M); posteriormente, os materiais preparados foram carbonizados em forno tubular a 800 ºC por 4 h. As amostras foram nomeadas da seguinte forma: TW-C (cascas pirolisadas sem HTC), TW-Fe-0,5-C / TW-Fe-1,0-C / TW-Fe-2,5-C (HTC e cascas pirolisadas) e TW-Fe-2,5 (cascas com HTC sem pirólise). As propriedades físico-químicas dos ACs foram determinadas por análise elementar, teor de cinzas, acidez e basicidade, para correlacionação com o seu desempenho no processo de adsorção. A cinética de adsorção e isotérmicas de adsorção de Ni(II) nos ACs foi avaliada nas seguintes condições operacionais: 2,5 g L-1 de AC, 25 ºC e pH 6, aplicando os modelos cinéticos de pseudo-primeira ordem, pseudo-segunda ordem e Elovich, bem como as isotérmicas de adsorção de Langmuir, Freundlich e a Equação Geral da Isotérmica (GIE) de Tóth. O carvão TW-C apresentou os melhores resultados de adsorção e removeu 99% de Ni(II) a pH 9. Os modelos cinéticos que melhor descreveram o processo de adsorção foram o de pseudo-segunda ordem (TW-Fe-2.5-C) e Elovich (TW-C). O GIE de Tóth apresentou o melhor ajuste, no entanto, os seus parâmetros não apresentaram significância estatística no nível de confiança de 5%, sendo rejeitado. O modelo de Freundlich foi capaz de representar os dados experimentais com certa precisão (R² atingiu 0,9557 e 0,9785 para TW-C e TW-Fe-2,5-C, respectivamente) e significância estatística de acordo com o teste t e o teste F.
First of all, I would like to thank my parents, Edson and Claudete, without whom I would not be given so many opportunities, I thank you for the support and encouragement during all these years of graduation and for sharing with me the challenges and difficulties faced away from home. I thank my brother for the partnership, complicity, for being present even with the distance. I thank my friends Pedro and Larissa, for their support during this stage and for their friendship over the years. To my supervisor, teacher and friend Tatiane, for all the help, advice and opportunities during the undergraduate years and later with the master's degree. I am grateful to my co-supervisor José, who was fundamental in the execution of this work and for whom I learned to cultivate respect and admiration. I thank my supervisor, Professor Helder, for the opportunity and confidence. My laboratory friends Fernanda, Adriano and Gabriel, who shared their knowledge and helped me with the execution of my practical work. I thank Maria João, technician at the Chemical Process Laboratory, for being helpful and patient. I would like to thank Professor Margarida and the Mountain Research Center (CIMO) for their assistance with my analysis. I am grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020).

Alternatives to deal with municipal solid waste (MSW), such as mechanical biological treatment (MBT) plants, are a trend. In these plants, the organic matter is digested by anaerobic bacteria, generating biogas and reducing the solid mass, generating simultaneously a solid compost and a liquid leachate as side-streams. The leachate has a complex composition and cannot be treated by conventional wastewater treatment methods, while the compost is mainly used as an agriculture fertilizer, but the amount produced is higher than its demand. This work deals with the valorization of compost to produce hydrochars and biochars, through hydrothermal carbonization (HTC) and pyrolysis, respectively, with suitable properties to serve as catalysts for the catalytic wet peroxide oxidation of the landfill waters generated in MBT (TOC = 27 g L-1, COD = 60 g L-1, 38.8 mS/cm and 5 g L-1 of chloride ions). Seven catalysts were produced from compost and characterized by several techniques. The catalysts were subjected to screening tests of H2O2 decomposition and the best two were selected to be further studied in the catalytic wet peroxide oxidation (CWPO) of leachate. The experimental conditions of the process, temperature, pH, catalyst load and H2O2 addition were studied seeking optimization. The best experimental conditions found were T = 80 ºC, pH = 3.0, 7.2 g L-1 of catalyst, 85.71 g L-1 of H2O2, added in five batches each hour. Under these experimental conditions, the hydrochar prepared at 230 ºC (HTC-230) achieved removal of 43 % of chemical oxygen demand (COD) and total organic carbon (TOC), turbidity, aromaticity, phenols, chlorides and 5-day biological oxygen demand, (BOD5) removals of 52, 95, 93, 72, 35 and 93 %, respectively. Resins were used to pre-treat the leachate, in order to enhance the CWPO results. Using a cationic adsorption resin (TP-207), considering again operating conditions of T = 80 ºC, pH = 3.0, 7.2 g L-1 of catalyst, 85.71 g L-1 of H2O2, the catalyst HTC-230 achieved 62 %, 55 %, is 97 %, 95 %, 46.5 %, and 97 % for COD, TOC, turbidity, aromaticity, chlorides, and BOD5.
As unidades de tratamento mecânico e biológico (TMB) são alternativas para lidar com os resíduos sólidos urbanos (RSU). Essas unidades através da digestão anaeróbia da matéria orgânica, geram biogás e reduzem a massa sólida, porém geram um resíduo sólido (convertido em composto) e águas lixiviantes (ou lixiviado) como sub-produtos. O lixiviado tem uma matriz complexa, o que inviabiliza o seu tratamento pelos métodos convencionais, enquanto o composto é usado principalmente como fertilizante agrícola. Este trabalho tem como objetivo a valorização do composto para a produção de materiais carbonáceos, através de carbonização hidrotérmica (CHT) e pirólise, respectivamente. Os materiais obtidos, com propriedades para atuarem como catalisadores no processo de oxidação catalítica com peróxido de hidrogénio (CWPO), são posteriormente usados no tratamento do lixiviado (TOC = 27 g L-1, CQO = 60 g L-1, 38,8 mS / cm e 5 g L-1 de iões cloreto). Neste trabalho foram produzidos sete catalisadores a partir de composto e caracterizados por diversas técnicas. Após testes de screening da atividade catalítica na reação de decomposição de H2O2, dois deles, o primeiro de pirólise e o segundo de CHT, C-800 e HTC-230, foram selecionados para ensaios de CWPO do lixiviado. Foram estudadas as condições experimentais para otimizar o processo, variando temperatura, pH, carga de catalisador e adição de H2O2. A condição experimental ótima encontrada foi T = 80 ºC, pH = 3,0, 7,2 g L-1 de catalisador, 85,71 g L-1 de H2O2, adicionados em cinco doses com 1 h de intervalo. Sob essas condições experimentais, o catalisador HTC-230 permitiu remoções de 43, 52, 95, 93, 72, 35 e 93% de carência química de oxigénio (CQO), carbono orgânico total (TOC), turbidez, aromaticidade, fenóis, cloretos e carência biológica de oxigénio de 5 dias (CBO5), respectivamente. Afim de potencializar os resultados de CWPO foram utilizadas resinas para pré-tratar o lixiviado. Utilizando a resina de adsorção catiónica TP-207, em condições de T = 80 ºC, pH = 3,0, 7,2 g L-1 de catalisador, 85,71 g L-1 de H2O2, o catalisador HTC-230 permitiu remoções de 62, 55, 97, 95, 46,5 e 97% de COD, TOC, turbidez, aromaticidade, cloretos e CBO5.

Tese de doutoramento em Química e Engenharia Biológica
Mediterranean countries are known to have favorable conditions for olive oil production. The three-phase extraction technology demands the addition of hot water to the process, and olive oil, olive cake and olive mill wastewater (OMW) are produced. An approach for using this waste as a renewable resource is of greater interest. Accordingly, the present investigation aims the OMW valorization, by producing high-value compounds (lipase and methane) while degrading this waste. Thus, the research work presented in this thesis essentially describes a study about an integrated process, where the effluents are firstly submitted to a lipase producing aerobic fermentation, followed by an anaerobic degradation process, to produce methane. This work is of great interest, since Portugal is one of the world leading producers of olive oil, with crescent production values from campaign to campaign, in the last years. This work was started with a study about the major problem attributed to the olive mill wastewaters (OMW), the phenolic compounds toxicity. These experiments showed that the nonconventional yeasts Y. lipolytica, C. rugosa and C. cylindracea are able to grow in different phenolic compounds, usually found in OMW. This was later confirmed in bioreactor batch experiments with OMW-based media, where the studied yeasts, not only were capable of achieving similar cell growth, to glucose synthetic media, but also to highly consume the existing and analyzed phenolic compounds. The experiments on batch fermentations, with OMW-based media, were then performed in Erlenmeyer baffled flasks, in order to study the effect of ammonium, cell and surfactant addition as well as to investigate the use of different yeast strains; Candida rugosa (PYCC 3238 and CBS 2275), Candida cylindracea CBS 7869 and Yarrowia lipolytica (CBS 2073, W29 ATCC 20460 and IMUFRJ 50682); and different non-diluted OMW. C. cylindracea was the best strain concerning the effluent degradation. After preliminary tests, a study of optimal batch and fed-batch conditions was performed in bioreactor, using Candida rugosa CBS 2275, Candida cylindracea CBS 7869 and Yarrowia lipolytica W29 ATCC 20460. It was confirmed that C. cylindracea CBS 7869 was the best lipase-producing yeast (6 U mL-1). However, using a fed-batch strategy, with cell pre-growth directly on the bioreactor, C. rugosa CBS 2275 was the strain that obtained the best values of lipase (17 U mL-1); achieving at the same time, a significant effluent degradation (64 % of COD, 27% of phenolics and 77% of total lipids). Anaerobic biodegradability tests showed that the aerobic treatment had a positive effect on the anaerobic degradation of the OMW. Best results were achieved for the initial concentration of 5 g COD-treated OMW L-1, where 78% of the COD added was recovered as methane. Furthermore, when the COD degradation in the aerobic step was higher, even better results were possible to achieve, with a faster conversion of COD to methane. The obtained results demonstrates that the olive mill wastewaters (OMW) are becoming a competitive and valuable growth medium in fermentation processes and also the potential application of non-conventional lipolytic yeasts for OMW valorization, for biomass and enzymes production. This treatment was successful to detoxify the effluent, having a very positive effect in the anaerobic digestion. The utilization of this valorization process will possibly have a positive impact on the environmental problem of OMW management.
Os países que envolvem o Mediterrâneo são conhecidos pelas suas condições favoráveis para a produção de azeite. A tecnologia de extracção de azeite com o sistema em contínuo de 3 fases exige a adição de água quente ao processo, o que dá origem à produção de azeite, águas ruças (OMW) e bagaço. A utilização deste efluente (águas ruças) como um recurso renovável apresenta-se como uma abordagem de elevado interesse, a este problema. Deste modo, o presente trabalho de investigação tem como finalidade a valorização das águas ruças, com produção de produtos de elevado interesse industrial (lipase e metano) enquanto se diminui a carga poluente do resíduo. Assim, o trabalho de investigação apresentado nesta tese descreve essencialmente o estudo de um processo integrado, onde os efluentes são primeiramente submetidos a uma fermentação aeróbia com produção de lipase, à qual se segue um processo de degradação anaeróbia com produção de metano. Este trabalho é de elevado interesse, dado que Portugal está entre os líderes mundiais de produção de azeite, com crescentes valores de produção de campanha para campanha, nos últimos anos. Assim, este trabalho foi iniciado com um estudo focado no problema mais importante associado às águas ruças, a toxicidade dos compostos fenólicos. Estes ensaios mostraram que as leveduras não-convencionais Y. lipolytica, C. rugosa e C. cylindracea são capazes de crescer nos diferentes compostos fenólicos, que frequentemente constituem as águas ruças. Estes resultados foram mais tarde confirmados em bioreactor, onde as referidas leveduras não só foram capazes de crescer, tanto ou até melhor ao que crescem em meio de glucose, como também foram capazes de consumir uma parte considerável de cada composto fenólico, acompanhado ao longo das fermentações. Foram então iniciados os ensaios em descontínuo em matrazes utilizando meio de águas ruças, de modo a fazer um estudo preliminar sobre o efeito da adição de amónio, surfactante e a da concentração de células, bem como o efeito do uso de diferentes leveduras, nomeadamente Candida rugosa (PYCC 3238 e CBS 2275), Candida cylindracea CBS 7869 e Yarrowia lipolytica (CBS 2073, W29 ATCC 20460 e IMUFRJ 50682) e diferentes amostras de águas ruças não diluídas. Foram seleccionadas algumas condições e a C. cylindracea foi a melhor levedura no que diz respeito à degradação do efluente. Depois destes testes preliminares, estudos sobre as condições óptimas a utilizar em descontínuo e semicontínuo foram efectuados em bioreactor, utilizando Candida rugosa CBS 2275, Candida cylindracea CBS 7869 e Yarrowia lipolytica W29 ATCC 20460. Concluiu-se que a C. cylindracea CBS 7869 é a melhor produtora de lipase em fermentações em descontínuo (6 U mL-1), no entanto, utilizando o modo semi-contínuo, com pré-crescimento das células directamente no reactor a C. rugosa CBS 2275 surge como a melhor levedura produtora de lipase, com 17 U mL-1, e com óptimos valores de degradação do efluente (64 % de CQO, 27% de compostos fenólicos totais e 77% dos lípidos totais). Os testes de biodegradabilidade anaeróbia demonstraram que a etapa de tratamento aeróbio que o antecede tem um efeito positivo. Em ensaios posteriores, foram obtidos melhores resultados para a concentração inicial de 5 g L-1 CQO de águas ruças tratadas, com 78 % de conversão do CQO em metano. Mais, verificou-se que quanto melhor é a degradação de CQO na etapa aeróbia do processo integrado, melhores foram os resultados na etapa seguinte, com uma conversão de CQO em metano mais rápida. Os resultados obtidos demonstram que as águas ruças se estão a tornar num meio de crescimento competitivo e importante, mas também o potencial das leveduras lipolíticas não convencionais nos processos fermentativos, para a valorização de águas ruças, com produção de enzimas e biomassa. O sucesso destes processos, na posterior etapa de digestão anaeróbia teve um efeito bastante positivo. A utilização deste processo integrado de valorização de águas ruças poderá assim ter um impacto benéfico para a resolução do problema relacionado com a gestão ambiental das águas ruças.

Dissertação de Mestrado Integrado em Engenharia Química apresentada à Faculdade de Ciências e Tecnologia
O aumento das preocupações relativas à quantidade e qualidade de água de consumo, levou à necessidade de regulamentar a descarga de efluentes para o meio ambiente. De salientar as águas-ruças que dada a sua elevada carga orgânica, a sua baixa biodegradabilidade e o seu carácter fitotóxico, necessitam de um processo de tratamento eficiente. Contudo esses efluentes possuem na sua constituição elevadas quantidades de compostos fenólicos que devidamente isolados e nas concentrações adequadas, apresentam propriedades antioxidantes e anti-inflamatórias, benéficas na saúde humana. Este trabalho teve como principal objetivo integrar um processo de valorização e tratamento destes efluentes recorrendo a processos de separação por membranas, processo de adsorção/permuta iónica e processos de oxidação avançados.Dois lotes do mesmo efluente obtidos pelo método de extração tradicional, foram submetidos a um pré-tratamento que visou a redução do diâmetro de partículas para a etapa de ultrafiltração (UF). Nesta etapa do estudo considerou-se o efluente tratado pelo crivo de 75 µm com valores de rejeição de TPh de ~1%, 6 – 8% de CQO e 31 – 35% de SST para os diferentes lotes. O pré-tratado foi sujeito a um processo de UF, tendo como objetivo a separação de compostos de elevado peso molecular. O efeito das variáveis pressão transmembranar (PTM) e temperatura na remoção de CQO e TPh foi estudado usando duas membranas de UF. Obtiveram-se como condições ótimas de operação, 1.5 bar, 25 °C e a escolha da membrana de maior MWCO. De seguida, procedeu-se ao ensaio de concentração para as condições selecionadas, obtendo-se uma remoção de CQO e TPh de 20,6% e 26,8%, respetivamente.Partindo do permeado obtido no processo de UF e tendo como objetivo a obtenção de um permeado depurado e um concentrado rico em compostos fenólicos, realizou-se o estudo da filtração com uma membrana de nanofiltração (NF). No âmbito deste estudo, avaliou-se a influência das variáveis queda de pressão (¿P), temperatura e pH, na remoção da CQO, TPh e no fluxo de permeado tendo por base um planeamento fatorial a dois níveis e do qual se obteve as seguintes condições ótimas: 18 bar, 25 °C e pH de 2.7, correspondentes a uma remoção de CQO e TPh de 82,9% e 93,8%, respetivamente.O concentrado da NF, foi depois submetido a um processo de adsorção com objetivo de isolar a fração fenólica. Para isto, recorreu-se a dois tipos de adsorvente, um não iónico e outro aniónico de base forte. O efeito do pH foi estudado, tendo-se obtido para ambas as resinas um pH ótimo de 7. A resina não iónica e aniónica, apresentaram respetivamente, uma eficiência de adsorção máxima de TPh de 57,2% e 73,2% para uma concentração de 120 g resina / L. Os ajustes das isotérmicas obtidas foram conseguidos com o modelo de Freundlich.Por forma a cumprir a legislação relativos aos limites de descarga, submeteu-se o permeado da NF a um tratamento final pelo processo de Fenton. O efeito das razões [H2O2] / CQO (w/w) e [H2O2] / [Fe2+] (M/M) na remoção de CQO e TPh foram estudados, através de um planeamento fatorial a dois níveis, tendo-se obtido um ótimo de 2.1 para a razão [H2O2] / CQO e 12.0 para a razão [H2O2] / [Fe2+], sendo estes correspondentes a uma remoção de 53,1% de CQO e 100% de TPh.Os resultados obtidos demonstram que existe potencial para a obtenção de compostos fenólicos a partir dos resíduos de azeite, sendo para isso necessário a integração de um conjunto de processos de separação.
The increasing awareness regarding quality of drinking water is leading to the need of regulating effluents discharge. Of especial concern are olive-mill wastewater due to their high organic load content, low biodegradability and phytotoxic content. Thus, efficient treatment is required. However, those effluents have high content of phenolic compounds which, when isolated and in suitable concentrations, show antioxidant and anti-inflammatory proprieties important to human health. The aim of the research carried out consisted in the valorization of olive-mill wastewater by membrane separation processes, adsorption/ionic exchange processes and advanced oxidation processes (Fenton).Two lots from the same effluent were obtained by the traditional extraction underwent a pre-treatment aiming to reduce the diameter of particles before UF. The optimal sieve was 75 µm with TPh rejection values of ~1%, 6 – 8% of COD and 31-35% of TSS for the two different lots.The sieved effluent was used for UF in order to separate compounds with high molecular weight. The effect of transmembrane pressure (TMP) and temperature on the removal of COD and TPh in two UF membranes was studied. The optimal operating conditions were 1.5 bar and 25 °C. Moreover, the larger MWCO membrane. Should be used, it with these conditions concentration was performed, obtaining a COD and TPh removal of 20,6% and 26,8%, respectively.In order to obtain a purified permeate and a phenolic-rich concentrate, the permeate obtained from the UF process was treated by nanofiltration (NF). The influence of ¿P, temperature and pH in the removal of COD, TPh and permeate flow were studied using a 2-level full factorial experimental design. The following optimal conditions were obtained: 18 bar, 25 °C and a pH 2.7, which corresponded to 82,9% and 93,8% of COD and TPh removal, respectively for the concentration process.With the objective of isolating the phenolic fraction present in the NF concentrate was subjected to an adsorption process. For that purpose, two types of adsorbents were used, a non-ionic and an anionic of strong base. The effect of pH was studied and for both resins an optimal pH of 7 was achieved. A maximum TPh adsorption of 57,2% and 73,2% for the non-ionic and anionic resins, respectively, were achieved for a S/L ratio of 120. Experimental equilibrium data were well fitted with the Freundlich model.To fulfill the discharge limits in order to comply with the legislation, the permeate obtained by NF was treated by Fenton’s process. The effect of [H2O2]/COD (w/w) and [H2O2]/[Fe2+] (M/M) in COD and TPh removal were studied using 2-level full factorial experimental design, where 2.1 was the optimum for [H2O2]/CQO ratio and 12.0 for [H2O2]/[Fe2+] ratio, corresponding to 53,1% of COD and 100% of TPh removal.OMW showed to be an interesting source of phenolic compounds, thus being necessary to integrate a set of separation processes.