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- Electrochemical treatment of sanitary landfill leachatesPublication . Fernandes, Annabel Dias Barrocas; Lopes, Ana Maria CarreiraSanitary landfill leachate is one of the major environmental problems concerning water pollution, since it is a very complex wastewater containing different heavy metals, organic and inorganic compounds, some of them refractory and toxic, which possesses colour and odour. Optimal leachate treatment, in order to fully reduce the negative impact on the environment, is today a challenge, since the conventional treatment methods used are not enough to reach the level of purification needed. For this reason, several advanced technologies have been studied for the treatment of sanitary landfill leachates and among them electrochemical methods have received great attention. In fact, electrochemical technologies have shown high efficiency in the elimination of persistent pollutants and several studies have reported its application in wastewater treatment. The objective of the work described in this thesis was to evaluate the application of two electrochemical methods, electrocoagulation and electrochemical oxidation, in the treatment of sanitary landfill leachates. Studies were performed with different leachate samples, collected at different sanitary landfill facilities, at different points of the treatment plants existed and in different seasons of the year. Different cell configurations and electrode materials were experimented. Operational variables such as applied current/potential, stirring, flow rate and electrolysis time were studied. Pollutants removal, mineralization and biodegradability indexes and energetic costs were also assessed. The results obtained demonstrated that electrocoagulation and electrochemical oxidation are effective technologies to treat leachates from sanitary landfills. Depending on the leachate characteristics, electrochemical treatments can be applied as pre-treatment or post treatment of biological processes. For leachates with high content in organic matter, electrochemical oxidation was more effective when applied after the biological treatment, eliminating the refractory organic matter remaining. Energy consumptions of 15 and 21 W h (g COD)-1 were achieved at laboratory and semi-pilot scales experiments, respectively. For leachates designated as “old” or with low biodegradability index, electrochemical oxidation process was more efficient when applied to the raw leachate, without any kind of pre-treatment. Chemical oxygen demand removals above 90% were achieved with energy consumptions of 78 W h (g COD)−1. For leachates with a high amount of solids, the application of an electrocoagulation process before the electrochemical oxidation enhanced the treatment efficiency. Electrocoagulation assays performed led to reductions in organic load of 50% with energy consumptions of 2 W h (g COD)−1. Furthermore, the combined electrocoagulation/ electrochemical oxidation treatment, when applied to raw leachates, enhances the biodegradability of the organic pollutants, improving the performance of the subsequent biological process. An increase in the biodegradability index from 0.3 to 0.9 was attained for the combined assays performed, with chemical oxygen demand removals above 95%. Moreover, this combined treatment has the advantage of being able to use the simultaneous cathodic reduction to remove heavy metals from the leachate, since these processes reduce the metal ions by depositing them onto the cathode. However, when solids content is low, it is preferable to apply only the electrochemical oxidation process, since it does not have the disadvantage of sludge production. The experiments using Ti/Pt/PbO2 anodes showed that this material can be successfully used for the treatment of sanitary landfill leachates, leading to lower energy consumptions than those obtained with boron doped diamond anodes. Both anode materials presented similar chemical oxygen demand removal kinetics and, despite boron doped diamond anodes yields higher mineralization indexes, Ti/Pt/PbO2 promotes higher levels of total and ammonia nitrogen removals.
- Adaptações curriculares não significativas para aprendizagem do Som no 8º anoPublication . Fernandes, Annabel Dias Barrocas; Soares, Sandra da Costa Henriques; Prata, Célia Maria BorgesA Escola Inclusiva reflete um modelo educacional que visa garantir a participação, aprendizagem e desenvolvimento de todos os alunos, independentemente das suas características, competências, limitações ou diferenças, respeitando a diversidade e promovendo a igualdade de oportunidades. Este modelo educacional aposta na diferenciação do currículo para promover a equidade, suportando-se em medidas de apoio à aprendizagem, organizadas em diferentes níveis de intervenção, de acordo com as respostas educativas necessárias para cada aluno adquirir uma base comum de competências, valorizando as suas potencialidades e interesses. Cada nível de intervenção contém medidas que inferem as atitudes e medidas que inferem o currículo, sendo estas últimas as mais desafiadoras e as que mais resistência encontram à sua implementação. Neste trabalho de investigação desenvolveu-se uma proposta de Adaptações Curriculares Não Significativas para o domínio “Som” da disciplina de Físico-Química do 8º ano do 3º ciclo do ensino básico e aplicou-se essa proposta, em contexto educativo real, para o subdomínio “Atributos do Som e sua Deteção pelo Ser Humano e Fenómenos Acústicos”. Os resultados obtidos evidenciaram uma melhoria na aprendizagem após a implementação da atividade adaptada, demonstrando que o desenvolvimento de Adaptações Curriculares Não Significativas com recurso a metodologias promotoras de aprendizagens ativas, tendo por base uma situaçãoproblema ligada ao dia a dia dos alunos, é uma estratégia eficaz para mitigar as dificuldades de aprendizagem associadas aos comportamentos diferenciados mais comuns.
- Sunlight-Driven AO7 Degradation with Perovskites (La,Ba)(Fe,Ti)O3 as Heterogeneous PhotocatalystsPublication . Rodrigues, Ana Sofia; Ciríaco, Lurdes; Pacheco, Maria José; Fernandes, Annabel; Mogo, Sandra; Lopes, AnaPerovskites of the (La,Ba)(Fe,Ti)O3 family were prepared, characterized, and utilized as heterogeneous photocatalysts, activated by natural sunlight, for environmental remediation of Acid Orange 7 (AO7) aqueous solutions. Catalysts were prepared by the ceramic (CM) and the complex polymerization (CP) methods and characterized by XRD, SEM, EDS, and band gap energy. It was found that catalytic properties depend on the synthesis method and annealing conditions. In the photocatalytic assays with sunlight, different AO7 initial concentrations and perovskite amounts were tested. During photocatalytic assays, AO7 and degradation products concentrations were followed by HPLC. Only photocatalysis with BaFeO3 -CM and BaTiO3 -CP presented AO7 removals higher than that observed for photolysis. However, photolysis leads to the formation of almost exclusively amino-naphthol and sulfanilic acid, whereas some of the perovskites utilized form lesstoxic compounds as degradation products, such as carboxylic acids (CA). Partial substitution of Ba by La in BaTiO3 -CM does not produce any change in the photocatalytic properties, but the replacement of Ti by Fe in the La0.1Ba0.9TiO3 leads to reduced AO7 removal rate, but with the formation of CAs. The best AO7 removal (92%) was obtained with BaFeO3 -CM (750 mg L−1 ), after 4 h of photocatalytic degradation with solar radiation
- Electrochemical Recovery of Phosphorus from Simulated and Real Wastewater: Effect of Investigational Conditions on the Process EfficiencyPublication . Sousa, Carlos Y.; Fernandes, Annabel; Amaro, Albertina; Pacheco, Maria José; Ciríaco, Lurdes; Lopes, AnaThe development of recovery processes has become essential in recent years as a strategy to minimize environmental pollution while boosting circular economy and sustainable development. Due to the exponential growth in agricultural production and the increased pollution of waterbodies, the production of fertilizers from recovered phosphorus has become an alternative to phosphate rock-based production. In this work, the effect of different operational parameters in the efficiency of the electrochemical recovery of phosphorus, from organic and inorganic sources, was investigated. Among the studied variables, the most significant was the electrode material utilized in the system. The use of magnesium sacrificial electrodes, as AZ31 alloys, led to phosphorus removal from solution of above 90%, allowing the recovery of both orthophosphates and organic phosphorus (glyphosate) as struvite, brucite, and other amorphous compounds. Since there is a lack in the literature about the use of magnesium electrodes in real wastewater electrochemical treatment, system efficiency was also evaluated using a sanitary landfill leachate, reaching 96% of phosphorus recovery. The specific energy consumption and faradaic efficiency of the phosphorus recovery process were also assessed.
- Reuse of Textile Dyeing Wastewater Treated by ElectrooxidationPublication . Pinto, Cláudia; Fernandes, Annabel; Lopes, Ana; Nunes, Maria João; Baía, Ana; Ciríaco, Lurdes; Pacheco, Maria JoséWastewater reuse has been addressed to promote the sustainable water utilization in textile industry. However, conventional technologies are unable to deliver treated wastewater with the quality required for reuse, mainly due to the presence of dyes and high salinity. In this work, the feasibility of electrooxidation, using a boron-doped diamond anode, to provide treated textile dyeing wastewater (TDW) with the quality required for reuse, and with complete recovery of salts, was evaluated. The influence of the applied current density on the quality of treated TDW and on the consecutive reuse in new dyeing baths was studied. The ecotoxicological evaluation of the process towards Daphnia magna was performed. After 10 h of electrooxidation at 60 and 100 mA cm−2, discolorized treated TDW, with chemical oxygen demand below 200 (moderate-quality) and 50 mg L−1 (high-quality), respectively, was obtained. Salt content was unchanged in both treatment conditions, enabling the consecutive reuse without any salt addition. For the two reuse cycles performed, both treated samples led to dyed fabrics in compliance with the most restrictive controls, showing that an effective consecutive reuse can be achieved with a moderate-quality water. Besides the water reuse and complete salts saving, electrooxidation accomplished an ecotoxicity reduction up to 18.6-fold, allowing TDW reuse without severe ecotoxicity accumulation.
- Pretreated Agro-Industrial Effluents as a Source of Nutrients for Tomatoes Grown in a Dual Function Hydroponic System: Tomato Quality AssessmentPublication . Afonso, Alexandra; Ribeiro, Carlos; Carvalho, Maria João; Correia, Tânia; Correia, Pedro; Regato, Mariana; Costa, Idália; Fernandes, Annabel; Almeida, Adelaide; Lopes, Ana; Carvalho, FátimaIn a zero-waste approach for the agro-industrial sector, this study aimed to evaluate the reuse of cheese whey wastewater (chemical oxygen demand = 2.1 g L−1) pretreated by immediate one-step lime precipitation followed by natural carbonation as a nutritive solution for tomato production in hydroponic systems. Pretreated effluent, diluted with groundwater (1:6) and supplemented with nutrients, was utilized to irrigate different hydroponic systems designed to assess the influence of tomato rooting type (free/confined−setup_A) and the feed’s solution level (with/without water deep−setup_B). Plants and fruit development, fruit physicochemical characteristics and sensory analysis, and effluent quality after reuse were analyzed. Good quality tomato production with high crop yield was obtained. The highest marketable tomato weight per plant (682 g) was observed in setup_B with a deep-bed system, but setup_A, with free or confined rooting, presented similar values. The type of rooting, within setup_A or water deep within setup_B, did not significantly influence plant and fruit characteristics. The highest maturity and flavor indexes were observed for setup_A with free rooting. Regarding sensory analysis, setup_A often scored the highest in terms of overall appreciation with free or confined rooting. The reuse of cheese whey wastewater in hydroponics reduced freshwater consumption for crop production, allowed for a treated final effluent and prevented soil degradation in a sustainable circular economy methodology.
- Reuse of Pretreated Agro-Industrial Wastewaters for Hydroponic Production of LettucePublication . Afonso, Alexandra; Regato, Mariana; Patanita, Mariana; Luz, Silvana; Carvalho, Maria João; Fernandes, Annabel; Lopes, Ana; Almeida, Adelaide; Costa, Idália; Carvalho, FátimaThe utilization of agro-industrial wastewaters (AIWWs), pretreated by immediate one-step lime precipitation + natural carbonation, as a nutritive solution for the hydroponic production of lettuce was evaluated. The AIWWs studied were olive mill wastewater (OMW), winery wastewater (WW), and cheese whey wastewater (CWW). Lettuces (Lactuca sativa L. var. crispa) were grown in a closed nutrient film technique hydroponic system, using the pretreated AIWWs (OMW-T, WW-T, and CWW-T) and a control nutrient solution (CNS). The growth and sensory analysis of lettuces and the environmental parameters of effluents after hydroponics were evaluated. The average number of lettuce leaves obtained with nutrient solutions prepared with AIWW-T was lower than that from CNS, but the highest lettuce chlorophyll content was attained with CWW-T, which also presented the best grow results. In general, sensory analysis did not show significant differences from the lettuces grown in the different pretreated AIWWs and CNS. As for the environmental parameters of the effluents from hydroponics, according to the Portuguese legislation, only the chemical oxygen demand of the OMW-T and WW-T presented slightly higher values than that of the environmental limit values for discharge in surface waters, showing the feasibility of using pretreated agro-industrial effluents in hydroponic lettuce cultivation, while obtaining a treated effluent, in a circular economy perspective.