Made available in DSpace on 2015-09-25T12:22:36Z (GMT). No. of bitstreams: 1 PDF - Edlamara Jessamynne Silva.pdf: 1271026 bytes, checksum: 8cf6cb184ab42e9039fae762cd960c07 (MD5) Previous issue date: 2014-02-21 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This study aimed to determine the best operating conditions of Fenton process for treatment of landfill leachate. The leachate collected from the landfill belongs to the metropolitan area of João Pessoa-PB and the experimental system was monitored on the premises Experiment Station Biological Treatment of Sewage (EXTRABES) of the State University of Paraíba in the city of Campina Grande-PB. Oxidation tests, coagulation/flocculation and sedimentation were carried out to examine the following operating parameters: Fenton reagent dosing (1, 2 , 3, 4 , 5, 6 , 8 and 12 gFe ), molar ratio [H 2 O 2 ]/[Fe 2+ ] (1, 2, 3, 6, 9 and 12), pH of oxidation (2, 3 and 4), oxidation time (5, 10, 15, 20 and 30 min), flocculation time (10, 20, and 30 min) and settling time (10, 15, 20 and 25 min). Assays were performed in Jar Test. All steps were submitted to the following methodology: for each jar, added the leachate, the FeSO 4 .7H 2 O, H 2 O and pH oxidation was adjusted with HCl. Under mechanics stirring (400 rpm) and after 10 seconds of rapid mixing, begins to count the oxidation time. After oxidation, added the alkalizing agent (NaOH) to pH 8.0, followed by a rapid mixing time of 10 seconds (400 rpm). Waited, then, the flocculation time (40 rpm) and, then, the settling time. A sample was collected and analyzes were performed according to the methods recommended by APHA (2005). After each step, was realized analysis of variance (ANOVA) and GT-2 method for defining the best result. The best results, under the conditions of this study were obtained with a Fe 2+ 2 concentration of 5 g.L -1 , molar ratio [H 2 O 2 ]/[Fe 2+ ] 9, pH of oxidation 2, oxidation time 20 min, flocculation time of 10 min, sedimentation time 15 min, with removal of 67% COD and 93% of true color. The final remaining COD was 3.84 gO and the true color of the final remnant was 394 uH. Obtained a high removal nitrite (93%), nitrate (69%), total phosphorous (97%), soluble orthophosphate (99.8%) and ammonia (87%). The addition of ferrous sulphate led to an increase in the concentration of total solids in the leachate, since the concentration of Fe contributes to the production of sludge in the process. / Este trabalho teve por objetivo determinar as melhores condições operacionais do processo Fenton para tratamento de lixiviado de aterro sanitário. O lixiviado coletado pertence ao aterro sanitário da região metropolitana de João Pessoa-PB e o sistema experimental foi monitorado nas dependências da Estação Experimental de Tratamentos Biológicos de Esgotos Sanitários (EXTRABES) da Universidade Estadual da Paraíba, localizada na cidade de Campina Grande PB. Foram realizados ensaios de oxidação, coagulação/floculação e sedimentação para analisar os seguintes parâmetros operacionais: dosagem do reagente Fenton (1, 2, 3, 4, 5, 6, 8, e 12 gFe 2+ .L -1 ), razão molar [H 2 O 2 ]/[Fe 2+ ] (1, 2, 3, 6, 9 e 12), pH de oxidação (2, 3 e 4), tempo de oxidação (5, 10, 15, 20 e 30 min), tempo de floculação (10, 20 e 30 min) e tempo de sedimentação (10, 15, 20 e 25 min). Os ensaios foram realizados em Jar Test. Todas as etapas foram submetidas à seguinte metodologia: para cada jarro, adicionou-se o lixiviado, o FeSO 4 .7H 2 O, o H 2 O e ajustou-se o pH de oxidação com HCl. Sob agitação mecânica (400 rpm) e após 10 segundos de mistura rápida, começou a contar o tempo de oxidação. Após a oxidação, adicionouse o agente alcalinizante (NaOH) até pH 8,0, seguida de um tempo de mistura rápida de 10 segundos (400 rpm). Esperou-se, então, o tempo de floculação (40 rpm) e, posteriormente, o tempo de sedimentação. Coletou-se uma amostra e realizaram-se as análises de acordo com os métodos preconizados por APHA (2005). Ao final de cada Etapa, foi realizada a análise de variância (ANOVA) e o método GT-2 para a definição do melhor resultado. Os melhores resultados encontrados, dentro das condições deste estudo, foram obtidos com a concentração de Fe 2+ de 5 g. L -1 , razão molar [H 2 O 2 ]/[Fe 2+ 2 ] 9, pH de oxidação 2, tempo de oxidação de 20 min, tempo de floculação de 10 min e tempo de sedimentação de 15 min, com remoção de 67% de DQO e 93% de cor verdadeira. A DQO remanescente final foi de 3,84 gO 2 .L -1 e a cor verdadeira remanescente final foi de 394 uH. Obtevese uma elevada remoção de nitrito (93%), nitrato (69%), fósforo total (97%), ortofosfato solúvel (99,8%) e nitrogênio amoniacal (87%). A adição de sulfato ferroso propiciou o aumento da concentração de sólidos totais no lixiviado, visto que a concentração de Fe contribui para produção de lodo no processo.

Made available in DSpace on 2015-09-25T12:23:00Z (GMT). No. of bitstreams: 1 PDF - Suely da Silva Rodrigues.pdf: 1150414 bytes, checksum: 8dd9efdbee9dac7b7d2fda5bd199d453 (MD5) Previous issue date: 2014-03-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent decades, the phenomenon of environmental contamination has reached global proportions. In this context, the industrial activity usually plays a major role due to the generation of a large amount of wastes, which have a high pollution potential if not properly treated. Textile industries are highlighted for their high water consumption and generation of large volumes of liquid waste containing high organic load and strong staining. In general, conventional treatments allow only partial removal of the load of pollutants present in such type of waste, which makes evident the need for new treatment systems. Based on new treatment technologies, focus is given on Advanced Oxidation Processes (AOP), which have a high efficiency of degradation face to several resistant pollutants, often allowing their full mineralization. This study aims to evaluate the applicability of oxidative processes in the treatment of synthetic textile wastewater. The method of hydrogen peroxide photolysis with ultraviolet radiation and the Photo-Fenton process using artificial radiation were employed. A 2 3 factorial design was performed to optimize the processes and evaluate the effect of discoloration. With this purpose, the following parameters were evaluated: concentration of iron (Fe 2+ ), dye and hydrogen peroxide (H 2 O 2 ) and the effect of pH. The concentration of dye ranged from 100 mgL to 500mgL -1 in the three phases; the concentration of hydrogen peroxide ranged from 500 mgL -1 to 1000 mgL -1 in the first and second phases, maintaining the initial pH (near neutral), and ranged from 1500 mgL -1 to 3000 mgL -1 in the third phase with pH variation of 4 and 5. Samples were treated for two hours with artificial radiation (germicidal lamp, 15W) and collected at 0, 15, 30, 45, 60, 90 and 120 minutes. The photodegradation of the samples was monitored by UV-Vis spectroscopy. Comparing these processes, Photo-Fenton with more acid pH (pH=4) showed the best results, followed by Photo-Fenton at pH=5 and H 2 O /UV process with initial pH. / Nas últimas décadas, o fenômeno da contaminação ambiental alcançou proporções globais. Dentro deste contexto, a atividade industrial costuma apresentar um papel de destaque, principalmente em razão da geração de uma vasta quantidade de resíduos, os quais, quando não adequadamente tratados, apresentam um elevado potencial poluente. Neste contexto é possível destacar as indústrias têxteis, as quais se caracterizam pelo elevado consumo de água e pela geração de grandes volumes de resíduos líquidos, contendo elevada carga orgânica e forte coloração. De maneira geral, tratamentos convencionais permitem uma remoção apenas parcial da carga de poluentes presentes neste tipo de resíduos, o que torna evidente a necessidade de novos sistemas de tratamento. Baseando-se nas novas tecnologias de tratamento, destaque pode ser dado aos processos oxidativos avançados (POAs), os quais apresentam uma elevada eficiência de degradação frente a inúmeros poluentes resistentes, muitas vezes permitindo a sua completa mineralização. O presente trabalho tem-se por principal objetivo avaliar a potencialidade dos processos oxidativos no tratamento de efluente têxtil sintético. Foi empregado a Fotólise do Peróxido de Hidrogênio com radiação ultravioleta e o processo fotoFenton utilizando radiação artificial. Realizou-se um planejamento fatorial 2 para otimizar os processos e avaliar o efeito de descoloração. Para tal, foram avaliados os seguintes parâmetros: concentração de ferro (Fe 2+ ), concentração de corante, concentração do peróxido de hidrogênio (H 2 O ) e efeito do pH. A concentração do corante foi de 100 mgL -1 a 500mgL -1 2 para as três etapas, a concentração do peróxido de hidrogênio foi de 500 mgL -1 a 1000 mgL -1 na primeira e segunda etapa mantendo o pH inicial (próximo de neutro), e de 1500 mgL -1 a 3000 mgL etapa com variação do pH de 4 e 5. As amostras foram tratadas durante duas horas com radiação artificial (lâmpada germicida, 15W) e as amostras foram recolhidas aos 0, 15, 30, 45, 60, 90 e 120 minutos. A fotodegradação das amostras foi seguida por espectroscopia UV-Vis. Comparando estes processos, o foto-Fenton com pH mais ácido (pH=4) apresentou os melhores resultados, seguido do foto-Fenton com pH=5 e do processo H 2 O /UV com pH inicial.

Na região sul do Brasil, muito aterros sanitários encontram-se próximos a áreas de mineração de carvão, cujos rejeitos são ricos no mineral pirita (FeS2). Este trabalho teve como objetivo estudar o tratamento de lixiviado de aterro sanitário com coagulantes férricos e ferrosos produzidos a partir da oxidação da pirita em meio aquoso. O lixiviado de aterro sanitário foi coletado no Aterro do Município de Campo Bom no Vale do Rio dos Sinos – RS. Pesquisou-se o efeito da dosagem do coagulante e avaliou-se comparativamente o desempenho com coagulantes comerciais produzidos a partir da dissolução de sucata ferrosa em ácido sulfúrico. Os resultados obtidos demostraram que os coagulantes férricos são eficiente no tratamento por coagulação dos lixiviados em dosagens superiores a 1 g/L. Verificou-se também que os coagulantes ferrosos podem ser aplicados no tratamento do chorume pelo processo Fenton (H2O2/Fe). Foram realizados ensaios considerando diferentes misturas de chorume e DAM, com e sem a adição de H2O2. O efeito de coagulação, em ambos os casos, melhorou as características do efluente em termos de carga orgânica, metais pesados e nutrientes. Porém, quando foi adicionado o H2O2 (Reação de Fenton), o efluente final apresentou melhores resultados em relação a cor, COT (Carbono Orgânico Total), nutrientes e, principalmente, em termos de bactérias do grupo coliforme. Os resultados demonstraram que a drenagem ácida de minas, especialmente as mais concentradas e ricas em Fe+2, podem ser empregadas a baixo custo como fonte de ferro para a Reação de Fenton. Desta maneira, surgem novas tecnologias para o tratamento primário de chorume com o uso de coagulante férricos e ferrosos produzidos a partir da oxidação da pirita presente em rejeitos de carvão. / In southern Brazil, most landfills are close to coal mining areas, whose tailings are rich in the mineral pyrite (FeS2). This work aimed at studying the treatment of landfill leachate with ferrous and ferric coagulants produced from the oxidation of pyrite in aqueous media. The landfill leachate was collected in the landfill of the city of Campo Bom in the region of Vale do Rio dos Sinos – RS, Brazil. The effect of the dosage of coagulant was evaluated and compared performance with commercial coagulants produced from the dissolution of ferrous scrap in sulfuric acid was researched for this paper. The results showed that ferric coagulants are effective in the treatment of leachate by coagulation at dosages greater than 1g / L. It was also found that the ferrous coagulants can be applied in the treatment of leachate by Fenton process (H2O2/Fe). Researches have been performed considering different mixtures of manure and AMD (Acid Mine Drainages), with and without the addition of H2O2. The coagulation effect in both cases, improved the characteristics of the effluent in terms of organic load, heavy metals and nutrients. However, when H2O2 (Fenton reaction) was added, the wastewater showed better results for color, TOC (Total Organic Carbon), nutrients, and especially in terms of coliform bacteria. The results showed that acid mine drainage, especially the most concentrated and rich in Fe +2, can be employed at low cost as a source of iron for the Fenton reaction. Thus, there are new technologies for the primary treatment of manure with the use of ferrous and ferric coagulant produced from the oxidation of pyrite present in coal tailings.

Nesse trabalho, catalisadores baseados em carvão de PET (poli (tereftalato de etileno)) e lama vermelha foram sintetizados a partir dos resíduos de PET em pó, gerado na reciclagem de garrafas PET, e lama vermelha (LV), importante resíduo da produção de alumínio pelo processo Bayer. Esses resíduos foram mecanicamente misturados na mesma quantidade de massa, submetidos pirólise (300°C) em forno tubular sob atmosfera inerte (N2) e ativadas em forno tubular em diferentes tempos (2 e 5 h) e temperaturas (800 e 900oC), usando ativação física de CO2. Os materiais foram caracterizados utilizando diferentes técnicas físico-químicas e avaliados quanto a capacidade de remoção de azul de metileno e paracetamol via processo Fenton heterogêneo empregando-se H2O2 como oxidante. Análise Termogravimétrica (TG) indicou maior perda de massa, cerca de 40%, para o material sem ativação (PET-LV), 6% para os ativados a 800°C (PET-LV 800/2h e PET-LV 800/5h) e 1% para o ativado a 900°C (PET-LV 900/5h). A maior perda para o PET-LV está relacionada com a decomposição de material carbonáceo proveniente do PET e as perdas de 6% podem estar relacionada a decomposição de carbonatos de ferro, formados durante a ativação física com CO2. Os difratogramas de raios X (DRX) mostraram que os materiais são formados por uma mistura complexa de fases cristalinas, como gibbsita (Al(OH)3), hematita (-Fe2O3), magnetita (Fe3O4) e/ou maghemita (γ-Fe2O3) e Siderita (FeCO3). A ativação do compósito PET/LV com CO2 em diferentes tempos e temperaturas, alterou a área específica e a reatividade dos materiais. Os materiais apresentaram áreas de 84, 114, 78 e 8 m2g-1 para PET-LV, PET-LV 800/2h, PET-LV 900/5h e PET-LV 900/5h, respectivamente. A Microscopia Eletrônica de Varredura (MEV) mostrou que houve alteração na morfologia dos materiais após ativação física com CO2 em diferentes condições. O PET-LV apresentou forma irregular e superfície rugosa, os materiais PET-LV 800/2h e PET-LV 800/5h apresentaram formas irregulares e aspecto esponjoso e o PET-LV 900/5h apresentou morfologia de um aglomerado de partículas de diferentes formas e tamanhos. As análises das características magnéticas indicam que todos os materiais apresentam fases de ferro magnéticas, possivelmente magnetita e/ou maghemita. A espectroscopia Mössbauer indicou a presença de Fe3+ no PET-LV, além de Fe3+ e Fe2+ para os materiais PET-LV 800/2h e PET-LV 800/5h, sendo Fe2+ espécies mais ativas no processo de oxidação. O espectro Mössbauer para o PET-LV 900/5h sugere um aumento no tamanho dos cristalitos das fases de ferro presentes. As análises de pH confirmaram que o processo de síntese dos catalisadores foi capaz de diminuir a basicidade da lama vermelha e o teste de estabilidade revelou que a atividade do material PET-LV 800/5h diminui gradualmente até o quarto ciclo de uso, sendo necessário a reativação do material. Os testes catalíticos para remoção de paracetamol mostraram que os catalisadores PET-LV e PET-LV 900/5h apresentaram remoção de paracetamol semelhante (cerca de 18%, apor 30 min de reação), e os materiais PET-LV 800/2h e PET-LV 800/5h removeram maior quantidade de paracetamol (26 e 40%, respectivamente), possivelmente pela presença de Fe2+. O PET-LV 800/2h foi ainda submetido a teste de adsorção no qual foram removidos 16% da solução de paracetamol, assim, confirmamos a contribuição dos mecanismos combinados de adsorção e oxidação via processo Fenton heterogêneo. Pode-se concluir então, que a utilização dos resíduos de PET e lama vermelha para a produção de catalisadores pode ser uma alternativa promissora do ponto de vista ambiental, uma vez que utiliza resíduos sólidos gerados em grande quantidade na indústria como precursores da produção de catalisadores que podem ser empregados no tratamento de efluentes líquidos. / In this work were studied catalysts based on PET (poly (ethylene terephthalate)) powder, generated through the recycling of bottles, and red mud (RM), an important residue of aluminum production by the Bayer process. These residues were mechanically mixed at the same weight proportion followed by a controlled thermal treatment in tubular furnace at 300°C for 1 h under N2 and then activated using CO2 physical activation at different times (2 and 5 h) and temperatures (800 and 900°C). The materials were characterized using different physicochemical techniques and evaluated for paracetamol removal from water by Fenton heterogeneous-type process using hydrogen peroxide as the oxidant. The Thermogravimetric Analysis (TGA) indicated highest loss of weight, about 40% for the material non-activated (PET-LV), 6% for the activate at 800°C (PET-LV 800/2h and PET-LV 800/5h) and 1% for activated at 900°C (PET-LV 900/5h). In the case of PET-LV, the highest loss weight is related to decomposition of carbonaceous materials from PET, and the weight loss of 6% is possibly to the decomposition of iron carbonates, formed during CO2 physical activation. The X-ray Diffraction (XRD) analysis revealed that the catalyst are formed by a complex mixture of crystalline phases, such as gibbsite (Al(OH)3), hematite (-Fe2O3), magnetite (Fe3O4) and/or maghemite (γ-Fe2O3) and Siderite (FeCO3). The CO2 activation at different times (2 and 5 h) and temperatures (800 and 900°C) of the PET/LV composites affected the surface areas and reactivity of the materials. The catalyst exhibit surface areas of 84, 114, 78 and 8 m2g-1 for PET-LV, PET-LV 800/2h, PET-LV 900/5h and PET-LV 900/5h, respectively. The Scanning Electron Microscopy (SEM) indicated that the materials morphology changed after the thermal treatment in different conditions CO2 activation. The Catalyst PET-LV presented irregular shape and rough surface with cavities whereas the PET-LV 800/2h and PET-LV 800/5h exhibit appearance of spongy-like along with cavities and the PET-LV 900/5h showed agglomerates of different shapes and sizes. The analysis of the magnetic properties indicates that all the catalysts present magnetic iron phases, possibly magnetite and/or maghemite. The Mössbauer Spectroscopy revealed the presence of Fe3+ in PET-LV catalyst. Fe3+ and Fe2+ in the PET-LV 800/2h and PET-LV 800/5h catalyst. The Mössbauer spectrum for PET-LV 900/5h catalyst suggests the increase in the size of the iron oxide crystallites. The pH analysis confirmed that synthesis process of catalyst was able to decrease the basicity of the red mud (possibly NaOH) and the stability test revealed that activity of PET-LV 800/5h catalyst gradually decreased until fourth cycle, leading to negligible catalytic activity. Catalytic tests for paracetamol removal showed PET-LV and PET-LV 900/5h catalyst presented similar drug removal (about 18%, after 30 min of reaction). The catalyst activated at 800°C (PET-LV 800/2h and PET-LV 800/5h) removed a higher amount of paracetamol (26 and 40%, respectively), possibly due to the presence of Fe2+. The adsorption test with PET-LV 800/2h presented 16% of paracetamol remove, thus confirming the contribution of the combined adsorption and oxidation process through Fenton-like heterogeneous process. It can be concluded that use of PET powder and red mud residues for catalyst production can be considered an environmental and promising alternative, since it uses solid residues generate in large amount in the industry as precursors for the catalyst production that can be applied for wastewater treatment.

L'oxydation du phénol et des crésols en milieu aqueux par le procédé électro-Fenton en utilisant une cathode en feutre de carbone a été étudiée. Les constantes absolues de dégradation du phénol et de l'o-crésol par les radicaux hydroxyles ont été obtenues en milieu acide (2,5 < pH < 3,0), étant respectivement égales à (2.62  0.23) x 109 M-1 s-1 et (3.70  0.19) x 109 M-1 s-1. Les sels de fer, cobalt, manganèse et cuivre ont été utilisés pour fournir les cations métalliques comme catalyseurs de la réaction de Fenton pour produire des radicaux hydroxyles. 10-4 M de sulfate de fer (II) a été la concentration optimale de catalyseur, permettant d'éliminer 100% du Carbone Organique Total (COT) de solutions aqueuses de phénol. Les principaux intermédiaires formés au cours de la destruction du phénol par le traitement électro-Fenton ont été identifiés comme l'hydroquinone, p-benzoquinone et le catéchol. Des acides carboxyliques tels que les acides maléique, fumarique, succinique, glyoxilique, oxalique et formique sont identifiés comme produits finis, avant la minéralisation complète. Au cours de l'électrolyse de l'o-crésol, les principales réactions initiales (environ 58%) ont été des additions électrophiles de radicaux hydroxyles sur le cycle aromatique, conduisant à la formation de 3-méthyl-catechol et méthyl-hydroquinone. Les acides fumarique et succinique étaient présents en phase initiale, mais il y avait également des traces d'acides pyruvique et maléique. Les acides oxalique, acétique et glyoxylique étaient prédominants en phase finale. Les expériences complémentaires avec l'électrolyse de la plupart des intermédiaires identifiés ont permis de proposer un mécanisme complet de minéralisation pour le phénol et l'o-crésol. Les principaux acides formés au début de la dégradation de m-crésol par le procédé électro-Fenton ont été les acides glycolique, succinique, malonique et pyruvique. Ces acides ont été rapidement convertis en acides glyoxilique, acétique, formique et oxalique. Après 450 minutes, de fortes concentrations d'acides acétique et oxalique ont persisté. Pendant l'électrolyse du p-crésol, les principaux acides identifiés en première phase ont été les acides glycolique, malonique, pyruvique et formique. Après 125 minutes, l'acide acétique a été prédominant, étant complètement dégradé après 550 minutes. Au cours du traitement d'effluent réel, le remplacement des anodes de Pt par BDD, dans les mêmes conditions expérimentales, a augmenté de manière significative l'efficacité du procédé électro-Fenton, en supprimant environ 98% de TOC en 20 heures de réaction. La présence de chrome n'a pas nui à l'efficacité du procédé. Des taux élevés de minéralisation ont prouvé l'efficacité de l'électro-Fenton comme un procédé d'oxydation avancée pour le traitement des rejets de décapage d'avions.

Up until relatively recently, the discharging of waste in the environment was the way of eliminating them, until the auto-purifying capacity of the environment was not sufficient. The permitted levels have been vastly exceeded, causing such environmental contamination that our natural resources cannot be used for certain uses and their characteristics have been altered. The main problem stems from waste coming from industry and agriculture, despite the fact that the population also plays an important role in environmental contamination. Phenols, pesticides, fertilizers, detergents, and other chemical products are disposed of directly into the environment, without being treated, via controlled or uncontrolled discharging and without a treatment strategy.In this general context, it is very clear that the strategy to continue in the search of solutions to this problem that every day presents a sensitive growth, mainly in the developing countries, will be guided to two fundamental aspects:- The development of appropriate methods for contaminated drinking, ground, and surfaces waters, and mainly- The development of appropriate methods for wastewaters containing toxic or non-biodegradable compounds.This thesis is focused in the second of these aspects. In this sense, it has been deepened in the treatment of organic compounds in aqueous solution by means of advanced oxidation processes (AOP), in the search of their elimination or transformation into more biodegradable compounds.The experimental work has been divided into four chapters. First part (chapter 3) is focused on the kinetic study of Fenton process for what two model compounds have been chosen: phenol, as reference (model compound widely studied) and an aromatic non-biodegradable compound, nitrobenzene.The second part (chapter 4) addresses to the optimisation of some treatment processes, such as photo-Fenton, H2O2/UV and Fe3+/UV-vis using different sources of artificial light and sunlight. The experimental work of this chapter was divided into two parts. In the first one, experiments were performed at laboratory scale at the University of Barcelona. In the second one, experiments in pilot plants were carried out at the EPFL (Ecole Politechnique Federale de Lausanne, Switzerland) and at the Plataforma Solar de Almería, Spain. The experimental results showed that the photo-Fenton process was the most effective method in the mineralization of the treated solutions. It is very important to stand out that it was more effective when solar light was used as radiation source.Chapters 5 and 6 represent an application of the treatment methods used in chapter 4, in which their influence on the biodegradability of an organic chloride compound (DCDE) and of waters coming from a textile industry was studied. For this final part of the thesis, the experimental work was carried out at the University of San Diego (San Diego, USA) and at the EPFL (Lausanne, Switzerland), respectively. In the case of water solutions of DCDE, H2O2/UV process was used as pre-treatment method to obtain oxidized solutions of 25, 50, 75 and 100% DCDE degrdation. After applying different biodegradability tests, it was observed that, as the percentage of oxidation increased, it increased the biodegradability of the treated solution, thus demostrating the effectiveness of the pre-treatment. In the case of treated textile wastewaters, a strategy was put in practice to obtain a general vision when it facing the case industrial wastewaters. When applied to the textile water under study, it was found that the photo-Fenton process should be used as post-treatment step of a biological process.

Abstract The object of this study was to investigate the synthesis of a nanoscale zero-valent iron slurry (NZVIS) for use in Fenton-like reactions, and to evaluate its efficiency for As(III) oxidation to As(V) in spiked deionized water and simulated groundwater containing humic acid. Furthermore, this study used injection of the nanoiron slurry combined with electrokinetic processes to remediate As(III) in soil. NZVI was prepared by a chemical reduction process. The efficiency of using 3 wt% soluble starch (SS) to stabilize NZVI was also studied. It was found that the SS could keep the nanoparticles dispersed for over one day. The NZVI was characterized by XRD, FE-SEM, ESEM-EDS, and EDS-mapping, to observe its morphology and crystal structure. In this research the iron species observed took non-crystalline forms. In water batch tests, studies in deionized water were compared with those in simulated groundwater with humic acid, and dissolved oxygen content was adjusted. Injection of NZVIS oxidized As(III) to As(V) in all cases. In both deionized water and simulated groundwater, it was found that when the dissolved oxygen(DO) content was not increased, the NZVIS generated non-selective oxidant OH¡E, thus reducing the As(V) production rate. When dissolved oxygen content was increased, the DO oxidized organic matter present in the simulated groundwater, allowing the OH¡E to react further with As(III) and increasing the As(V) production rate. Finally, a test was performed in actual groundwater under optimal reaction conditions, without increasing the dissolved oxygen content, for comparison of As(V) yield. The concentration of As(V) was found to be higher in this test (As(V) Conc. = 17.55 £gg/L) than when using simulated groundwater (As(V) Conc. = 4.63 £gg/L). This study further examined NZVIS injection combined with electrokinetic (EK) technology for the remediation of soil columns containing a low concentration (initial conc. = 100 mg/kg) and a high concentration (initial conc. = 500 mg/kg) of As(III). EK alone without injection of NZVIS (Test E-1) resulted in a residual soil As(V) concentration of 24 mg/kg in the low-concentration test group. In Test E-2, where NZVIS was injected into the anode reservoir, and Test E-3, where NZVIS was injected into the cathode reservoir, residual soil As(V) concentrations were 2.3 mg/kg and 3.4 mg/kg, respectively. The high-concentration test group was comprised of Test E-4 (EK alone without injection of NZVIS), Test E-5 (NZVIS injected into anode reservoir), and Test E-6 (NZVIS injected into cathode reservoir). In these tests, only soil sections 0.2 and 0.4 (normalized distance from anode reservoir) met soil regulation standards. Residual As(V) concentrations in soil sections 0.6, 0.8, and 1.0 are much higher than the regulatory standard. In soil section 1.0, the residual As(V) concentration was less in Test E-6 than in Test E-5 (116.6 mg/kg and 183.5 mg/kg, respectively). This may be because at high pH values, the iron surface does not corrode, instead arsenic adsorption prevails. Only a fraction of negatively charged As(V) species will migrate towards the anode resulting in a relatively low soil As(V) concentration near the cathode.

Spent caustic liquors (SCL) generated from crude oil refineries have characteristics of high COD (chemical oxygen demand) contents and relatively small generation rates as compared with general wastewater ones. The odorous naphthenates, phenolates, and sulfides in the liquors adversely affect the normal operation of the related wastewater treatment plants and effluent water qualities. This study aims at the reduction of COD in a naphthenic spent caustic liquor generated from a domestic refinery with crude processing and naphtha cracking units. Primary tests indicated that around 50% of the COD in the SCL could be biodegraded. Chemical oxidation methods were tried to possibly upgrade the COD removal. Experiments indicated that acidification of the SCL sample to pH 2-3 could reduce the COD from an average of 51,600 to 20,800 mg/L by removing the separated naphthenic acids. Fenton¡¦s method with oxidants of 20 mL/L 35% H2O2 and FeSO4.7H2O 5 g/L, oxidation time of 1 hour at conditions of pH 2-3 and 80-100oC, could reduce the COD of the acidified SCL from an average of 20,800 to 11,100 mg/L. The overall COD removal was around 78% and the efficiency is comparable to that of a traditional Wet Air Oxidation (WAO) process of around 75%. Economic analysis indicated that for treating the SCL of 80 m3/day by the traditional WAO process, an initial equipment cost of 10 millions USD and annual operating cost of around 1.5 millions USD are required. By the developed acidification-Fenton¡¦s process, an initial equipment cost of 0.7 million USD and annual operating cost of around 0.5 million USD are expected. The developed process can be superior to the WAO one.

This work increased the value of ferrite process (FP) in three directions: firstly, changed the inferiority of FP on cost by transforming the FP sludge into a catalyst; secondly, used ERFP and elutriation to promote the performance of FP; thirdly, developed Fenton oxidation as a pretreatment step for avoiding the interference from chelating agents. Six ferrite catalysts (MxFe(3-x)O4, M = Cu, Zn, Mn, Ni, Cr or Fe) formed from FP were tested. Experimental results indicate that the Cu-ferrite catalyst with a Cu/Fe ratio of 1/2.5 can completely convert CO to CO2 at an inlet CO concentration of 4000 ppm and a space velocity of 6000 hr-1 were held at 140¢J. The catalytic performance of Cu-ferrite did not reduce even when the concentration of O2 was just 1%. This work proves that the ferrite catalysts have good potential for catalyzing oxidation. For developing FP for effectively treating almost all heavy metal waste liquid, hence an extremely difficult treating target- simulated waste liquid was designed. It contains ten heavy metals - Cd, Pb, Cu, Cr, Zn, Ag, Hg, Ni, Sn and Mn, each at a concentration of 0.002 M. Although conventional FP could not be used to treat the simulated waste liquid completely, the enhanced FP, i.e. ERFP, could be used to satisfy regulatory limits. FeSO4 can be added in the extended stage of ERFP intermittently rather than continuously. The optimum operating parameters in the initial stage are pH = 9 , FeSO4 dosage = 0.2 mol/L, temperature = 90 oC, air supply rate = 3 L/min/L and reaction time = 40 min; in the extended stage, they are intermittent dosing, adding 10 mL 1M-FeSO4 solution per liter waste liquid every 5 min, pH = 9, temperature = 90 oC, air supply rate = 3 L/min/L and reaction time = 80min. Elutriation was conducted to reduce the cost of ERFP and ensure that the sludge met Toxicity Characteristic Leaching Procedure (TCLP) standards. An operating pH from 2.88 to 4 and an elutriation time of 6 h were recommended. Used Fenton oxidation to decompose chelating agent in waste liquid and then treated heavy metal by FP, this research showed that under proper operational conditions Fenton/ ERFP could completely solve the chelating agent interference problem. The best condition for decreasing EDTA using the Fenton method was: pH = 2, ferrous ion initial concentration [Fe2+]0 = 1¡Ñ10-2M, hydrogen peroxide addition rate = 5¡Ñ10-4 mol/min/L and reaction time = 10 min. Lastly, a lot of real waste liquids were treated satisfactorily by applying the results of this study.

In this study, aerobic biological treatment of opium alkaloid wastewater and the effect of gamma preirradiation and fenton&amp / #8217 / s oxidation were investigated. First, the biodegradability of alkaloid wastewater was investigated by batch reactors and wastewater was found to be highly biodegradable providing 83 &amp / #8211 / 90 % COD degradation. In order to evaluate the effect of irradiation, original wastewater and irradiated wastewaters (40 &amp / 140 kGy) were compared by means of BOD5/COD values and through aerobic batch experiments. Results indicated that irradiation imparted no further enhancement in biodegradability. Sequencing batch reactor (SBR) studies revealed that the treatment operation was not possible due to sludge settleability problem observed beyond an influent COD value of 2 g/L. Possible reasons for problem were investigated, and the high molecular weight, larger size and aromatic structure of the organic matters present in wastewater was thought to contribute to poor settleability characteristics. Some operational modifications including phosphate buffer addition cured the settleability problem. Influent COD was then increased to 5,000 mg/L. Significant COD removal efficiencies (&gt / 70 %) were obtained in SBRs fed with both original and irradiated wastewaters. Preirradiated wastewater provided a better settling sludge in comparison to original wastewater. Degradation of the complex structure was followed by GC/MS analyses, particle size measurements and enhancement in filterability. Pre-irradiation enhanced the filterability of wastewater more than Fenton&amp / #8217 / s treatment and degradation by irradiation was proved by GC/MS analyses.