Thèses sur le sujet « Advanced Photochemical Oxidation process »

A racionalização dos recursos hídricos tem sido uma das metas das indústrias em vários setores. Tais metas exigem inovações tecnológicas tanto para novos processos produtivos quanto para novas técnicas de tratamento e reutilização de água na cadeia de produção. Os custos elevados de água industrial no Brasil, particularmente nas regiões metropolitanas, têm estimulado as indústrias nacionais a avaliar as possibilidades de reúso. O objetivo deste trabalho é a aplicação do tratamento de águas de processo contendo polipropileno utilizando radiação ultravioleta e peróxido de hidrogênio, isto é, o sistema UV/H2O2, visando adequá-las para reúso no próprio processo, reduzindo a necessidade de captação de água pré-tratada e de descarte de efluente. A primeira parte do estudo consistiu na realização de experimentos em um sistema fotoquímico de batelada, empregando quatro diferentes correntes efluentes de processo, para a avaliação da viabilidade técnico-econômica do tratamento fotoquímico, bem como para a obtenção de dados referentes à cinética das reações fotoquímicas. Com base nas informações obtidas, na segunda parte do estudo foram realizados experimentos em um sistema fotoquímico contínuo, a fim de obter dados para o aumento de escala para aplicação industrial do processo de tratamento contínuo. Os resultados experimentais indicaram a viabilidade técnica de aplicação do sistema UV/H2O2 utilizando fonte de luz artificial para todas as correntes de processo estudadas, tendo sido alcançados níveis de remoção de matéria orgânica acima de 90%. No entanto, sob o ponto de vista econômico, apenas as correntes com baixo teor de carbono orgânico total dissolvido (COT), entre 6 e 12 mgC L-1, mostraram-se adequadas ao reúso, após o tratamento.
Rationalization of water use has been one of the goals in many industrial activities, and, in particular, in the petrochemical industry. Such goals demand technological innovations in the productive processes and in techniques for treatment and reuse of water in the production chain. The high costs of industrial water, particularly in some metropolitan regions, have stimulated the industries to evaluate the possibilities of water reuse. The objective of this work is to evaluate the feasibility of the UV/H2O2 photochemical process applied to the treatment of process waste water containing polypropylene, aiming at the reuse of the waste water in the as process water in the industrial complex, thus reducing the need for tap water supply and waste water generation rate. The first part of this study consisted of laboratory-scale experiments in a batch photochemical reactor with four different waste water streams to perform the technical and economical feasibility of the photochemical treatment, as well to obtain data on the degradation rate. Based on the results of the first part, the second part of this study consisted of experiments in a continuous photochemical reactor, aimed at obtaining experimental data for reactor scale-up. Experimental results indicate that the UV/H2O2 photodegradation process is able to remove more than 90% of the organic compounds contained in the waste water. However, only waste waters containing relatively low contaminant levels (between 6 and 12 mgC L-1) can be treated at economically favourable costs.

2008/2009
La nanotecnolgia rappresenta un approccio innovativo nella produzione industriale, e riflette la generale tendenza alla miniaturizzazione ed alla riduzione di scala che prevale in tutte le discipline tecnologiche. Da qui il crescente interesse nei confronti nei nanomateriali e dei materiali nanostrutturati, per lo sviluppo di nuovi prodotti innovativi e tecnologicamente avanzati, che trovino applicazione in molteplici campi. La presente tesi di dottorato si focalizza sulla strutturazione di nanomateriali a base di ossidi metallici, per applicazione come isolanti termici ad alta efficienza o come fotocatalizzatori per l’abbattimento dei contaminanti da acque reflue. Nel campo dell’isolamento termico l’attenzione è stata focalizzata su Al2O3, che, grazie alle sue uniche proprietà di tessitura, ottenute attraverso una scelta accurata delle condizioni di sintesi, ed all’elevata stabilità termica, è un materiale di forte interesse in questo settore. Lo studio della capacità di termoisolamento di materiali a base di Al2O3 ha rivelato una diretta dipendenza della diffusività e conducibilità termica dalle caratteristiche di tessitura e di struttura dell’ossido, e dalle modalità di agglomerazione. I risultati più rilevanti riscontrati nell’ambito di questa parte del lavoro hanno dato chiare indicazioni su come disegnare la strutturazione di un isolante termico: 1. Effetto del tipo di porosità presente (macro vs meso): l’aumento del contenuto di macropori determina una diminuzione del valore di conducibilità, ed un aumento di diffusività, per cui il materiale è un isolante termico; al contrario, la presenza di mesopori favorisce la riduzione di entrambe conducibilità e diffusività, per cui il materiale presenta proprietà di termoisolamento ed antifiamma; 2. Effetto del diametro dei mesopori: la modulazione del diametro dei pori a parità di porosità nella regione meso, non incide sul valore di diffusività e conducibilità, con il vantaggio che, aumentando le dimensioni, aumentano anche la resistenza meccanica e la stabilità termica dell’ossido; 3. Effetto della morfologia di assemblaggio del materiale: incide pesantemente sul trasferimento dell’energia termica, poiché, in presenza di un agglomerato hard, la conducibilità e la diffusività aumentano di un ordine di grandezza. Ne consegue che un materiale termoisolante deve avere una struttura mesoporosa ed una morfologia di tipo aggregato soft. È necessario evitare la sinterizzazione massimizzando la stabilità termica (es. mesopori di “grandi” dimensioni). L’analisi dei parametri di sintesi ha rilevato degli effetti sui processi di aggregazione nel gel-precursore di aerogel, che indirizzano in modo critico le proprietà di tessitura del prodotto finale. Il lavoro di ottimizzazione di tali parametri ha permesso di realizzare lo scale up del processo su scala industriale, da 200 ml a 25 L. La seconda parte del lavoro di ricerca è stata focalizzata sull’abbattimento di contaminanti da percolato di discarica ed acque reflue industriali per via fotocatalitica mediante processi di tipo APO. L’APO, ed in particolare la fotocatalisi con TiO2, si è rivelato un metodo di trattamento di efficiente e versatile, rendendo possibile la decontaminazione di reflui di diversa natura, dalle acque industriali al più complesso percolato di discarica. Lo studio dei parametri di processo ha evidenziato, infatti, la possibilità di semplificare il trattamento, a seconda della complessità del refluo. Mentre nel caso del percolato di discarica è necessario un trattamento con il sistema TiO2/H2O2/UV, in quanto, in virtù del sinergismo H2O2/UV, il contenuto di COD può essere portato a livelli sufficientemente bassi da permettere il completamento della decomposizione per via fotocatalitica, il refluo proveniente dall’industria del sughero può essere depurato anche in presenza del solo agente ossidante, o per effetto della sola fotocatalisi, in tempi ragionevolmente brevi rispetto a quelli richiesti per la decontaminazione del percolato (8 ore). In entrambi i casi è probabilmente possibile aumentare l’efficienza del processo mediante un’alimentazione in continuo dell’agente ossidante. In particolare, con l’approfondimento dello studio del trattamento delle acque industriali nel prototipo di reattore pilota, e la modellizzazione matematica dell’abbattimento dei contaminanti, è stato possibile parametrizzare il processo sulla base delle dimensioni dell’impianto, confermandone la fattibilità ed applicabilità su scala industriale.
XXII Ciclo
1980

Municipal wastewater treatment using biological nutrient removal generates large amounts of waste sludge. An effort is made to solubilize nutrients from sludge and reuse them in subsequent processes. The microwave-enhanced advanced oxidation (MW/H₂O₂-AOP) process using hydrogen peroxide as the oxidant was applied to the treatment of different organic slurries including wasted sludge, blood meal, and fish silage. The factors controlling phosphates, ammonia, and COD release into solution included inorganic acid addition, hydrogen peroxide dosage, treatment times and temperatures. Higher dosages and treatment temperatures yielded better solubilization of phosphates and ammonia. It was found that approximately all of the COD was solubilized at a treatment temperature of 80°C. Volatile fatty acid (VFA) concentrations were also found to have increased with the amount of inorganic acid added into treatment. Up to 25% of soluble COD was composed of acetic acid. Higher irradiation levels tended to be more effective in the solubilization of nutrients. In terms of trends of particle size distribution, detectable particles increased in size in acidic conditions, with the largest fraction of larger particles in a given sample being the treatment with highest irradiation power. In neutral condition treatments, the higher the irradiation power provided to the samples, the more spread out the particle sizes range. In alkaline condition treatments, an increase in smaller particles were found after treatment; higher power irradiation yielded significantly higher numbers of smaller particles. This study provided an insight into the athermal effects of theMW/H₂O₂-AOP. Blood meal solubilization for the purpose of its application as an organic feritilizer was investigated using theMW/H₂O₂-AOP. It was found that over the treatment temperature range of 60 to l20C, solids particle reduction, ammonia and orthophosphate production were achieved. Maximum solubility of chemical oxygen demand (COD) occurred at 80°C. Without the addition of acid, soluble COD decreased due to protein denaturation and coagulation out of the solution. Fish silage is also a valuable fertilizer for organic greenhouse hydroponics operations, but a pretreatment step is required. It was found that up to 26% of total Kjeldahl nitrogen could be released as ammonia with 6% hydrogen peroxide dosage at 170°C. An increase of nitrate/nitrite concentration was observed with higher hydrogen peroxide dosage and higher microwave temperature.

Waste activated sludge (WAS) and dairy manure (DM) present serious environmental concerns since they contain high levels of nutrients, organic matter and pathogens contained. The microwave enhanced advanced oxidation process (MW/H₂O₂-AOP) was used to treat these waste materials for solids disintegration, nutrients solubilization and pathogen destruction. For pathogen reduction, fecal coliform concentrations were found below detection limits (1000 CFU/L) immediately after treatment when sludge was treated at 70ºC with more than 0.04% of H₂O₂. Significant regrowth of fecal coliforms was observed after the treated samples were stored at ambient temperature for 72 hours. However, no regrowth was observed for samples treated at 70ºC with 0.08% H₂O₂ or higher, suggesting a complete elimination of fecal coliforms. With extracted cells that are EPS-free, orthophosphate could be released at lower microwave temperatures and lower H₂O₂ dosages, compared to our previous studies. The amount of DNA in solution was a good indicator of the extent of cell damage; the high concentration of DNA released into solution after treatment indicated significant cell damage. The effects of pre-microwave heating, microwave irradiation and post-microwave setting on nutrients and organic matters solubilization in continuous MW/H₂O₂-AOP were studied. Pre-microwave heating did not improve the overall orthophosphate solubilization, but helped in organic matter solubilization. It was beneficial to operate a continuous mode of the MW/H₂O₂-AOP at a longer retention time for organic matter solubilization, and at a shorter retention time for orthophosphate solubilization. Sludge settleability was greatly improved with the microwave treatment, with or without the addition of H₂O₂. It was found that 69 to 92% of the TP and up to 90% of TCOD in DM were in the soluble form, after continuous MW/H₂O₂-AOP with an exit temperature of 90oC and acid dosage of 1.0% (vol/vol). Acid addition was important in phosphate solubilization but the dosage of acid affect the solubilization to a lesser extent. For organic matter solubilization, acid played an important role – SCOD release increased with the increase of acid dosage. Higher microwave exit temperature resulted in higher SCOD and ortho-P solubilization.

El bisfenol A (BPA) i la tartrazina (TAR) pertanyen al grup de compostos que són potencialment nocius per a la recuperació d'aigües residuals. El BPA és un disruptor del sistema hormonal o disruptor endocrí, mentre que la TAR és un colorant azoic. Una diversitat d'indústries, especialment la indústria paperera i tèxtil, produeixen un gran volum d'aigües residuals que estan contaminades amb BPA i colorants. Per tant, els efluents que contenen tant BPA com colorants han de ser gestionats de manera eficient amb la finalitat d'evitar problemes ambientals vinculats a ells. Durant l'última dècada, s’han assajat diversos mètodes per a l'eliminació de BPA i TAR d'aigües residuals, resultant ser eficaços i potencialment aplicables a gran escala. No obstant això, la majoria d'ells encara enfronten problemes de costos, la qual cosa exigeix el seu desenvolupament. La nanofiltració (NF) ofereix una solució adequada per a l'eliminació de BPA i colorants de les solucions aquoses, degut a la seva capacitat per retenir substàncies orgàniques dissoltes. És per això que en aquest treball de tesi, es va utilitzar la NF en flux tangencial mitjançant membranes polimèriques per eliminar BPA i TAR de solucions aquoses. Addicionalment, la degradació de BPA i TAR durant els tractaments per Fenton, ozonación i enzimàtic sota diferents condicions d'operació, en combinació amb la seva posterior NF van ser assajats. Resultats indiquen que tant el BPA com la TAR poden ser eficientment degradats per aquests processos. L'ús d'un sistema integrat membrana-reactor va mostrar el potencial i les limitacions de l'ús dels processos d'oxidació avançada en conjunt amb membranes de NF per a la remoció del BPA i de la TAR. En general elevades eficiències de remoció van ser aconseguides amb les diferents membranes de NF utilitzades.
Bisfenol A (BPA) y tartrazina (TAR) pertenecen al grupo de compuestos que son potencialmente dañinos para la recuperación de aguas residuales. BPA es un perturbador del sistema hormonal o disruptor endocrino, mientras que la TAR es un colorante azo. Variedad de industrias, especialmente la industria papelera y textil producen un gran volumen de aguas residuales que están contaminadas con BPA y colorantes. Por lo tanto, los efluentes que contiene tanto BPA como colorantes, deben ser gestionados de manera eficiente con la finalidad de evitar problemas ambientales vinculados a ellos. Durante la última década, varios métodos para la eliminación de BPA y TAR de aguas residuales han sido probados, resultando ser eficaces y potencialmente aplicables a gran escala. Sin embargo, la mayoría de ellos todavía enfrentan problemas de costes, lo cual exige su desarrollo. La nanofiltración (NF) ofrece una solución adecuada para la eliminación de BPA y colorantes de las soluciones acuosas debido a su capacidad para remover sustancias orgánicas disueltas. Es por ello que en esta tesis, la NF en flujo cruzado usando membranas poliméricas fue utilizada para remover BPA y TAR de soluciones acuosas. Adicionalmente, la degradación de BPA y TAR durante los tratamientos por Fenton, ozonación y enzimático bajo diferentes condiciones de operación, en combinación con su posterior NF fueron ensayados. Resultados indican que tanto el BPA como la TAR pueden ser eficientemente degradados por estos procesos. El uso de un sistema integrado membrana-reactor mostró el potencial y las limitaciones del uso de los procesos de oxidación avanzada en conjunto con membranas de NF para la remoción del BPA y de la TAR. En general elevadas eficiencias de remoción fueron alcanzadas con las diferentes membranas de NF utilizadas.
Bisphenol A (BPA) and tartrazine (TAR) belong to the compounds which are potentially harmful during wastewater reclamation. BPA is a typical Endocrine Disrupting Chemical and TAR is an azo dye. Variety of industry, especially paper and textile industries produces a large volume of wastewater that is polluted with BPA and dyes. Therefore, BPA and dyes-charged effluents need to be efficiently managed in order to avoid environmental problems linked to them. During the last decade, several methods for BPA and TAR removal of wastewater have been found effective and potentially applicable for scaling up. However, most of them still face cost problems, thus demanding further development. It is generally accepted that nanofiltration (NF) offers an adequate solution for the removal of BPA and dyes from the aqueous solutions owing to its capacity to remove dissolved organics. In the present thesis, crossflow NF using thin film composite polymeric membranes were applied to reject BPA and TAR from aqueous solutions. Additionally, the degradation of BPA and TAR during Fenton’s, ozonation and enzymatic processes under different operational conditions, in combination with subsequent NF of low concentration remnant BPA and TAR and compounds derived from oxidation was investigated. Results indicate that BPA and TAR could be degraded efficiently in aqueous phase by Fenton, ozonation and enzymatic processes. The use of a membrane-reactor integrated system for BPA and TAR degradation demonstrated the potential and limitations of using advance oxidation processes, operated in a recycling mode coupled to a NF membrane. In general, high BPA and TAR removal efficiencies for several NF membranes were achieved.

En cuanto a la mejora de los Procesos de Oxidación Avanzada para el tratamiento de aguas residuales, se han diseñado y estudiado nuevos procesos catalíticos Fenton y ozonización catalítica para la eliminación de contaminantes orgánicos del agua. El proceso Fenton se ha realizado mediante peróxido de hidrógeno generado in situ, el cual se ha producido a partir de ácido fórmico y oxígeno sobre un catalizador de paladio soportado en alúmina. A continuación, se ha heterogeneizado totalmente el sistema utilizando un catalizador bimetálico Pd-Fe y se ha aplicado con éxito en la degradación de diferentes categorías de contaminantes orgánicos. La combinación de este proceso de oxidación con hidrodecloración ha obtenido una alta eficiencia en la degradación de clorofenoles. En cuanto al uso de diferentes sustitutos de H2, se ha observado una mayor eficiencia de la hidroxilamina en el proceso Fenton con generación in situ de peróxido de hidrógeno para efluentes neutros. Con respecto al desarrollo de nuevos materiales para ozonización catalítica, se ha estudiado la degradación de compuestos farmacéuticos mediante catalizadores de cobre-dawsonita. El cobre incorporado en la estructura de dawsonita presenta una mayor actividad en la ozonización catalítica con respecto a la muestra calcinada, cobre en solución y óxido de cobre soportado en alúmina.
Regarding to the improvement of Advanced Oxidation Processes for wastewater treatment, new catalytic Fenton process and catalytic ozonation were designed and studied in the removal of organic pollutants from water. Fenton process was performed using in situ generated hydrogen peroxide, which was produced from formic acid and oxygen over alumina-supported palladium catalyst. Then, the system was fully heterogenized by using bimetallic Pd-Fe catalyst and applied successfully for different categories of organic pollutants. The combination of the above oxidation process with hydrodechlorination led to high efficiency in the degradation of chlorophenols. The performance of different hydrogen substitutes in the Fenton process using in situ generated hydrogen peroxide showed higher efficiency of hydroxylamine for neutral solutions. Concerning the development of new catalytic materials for catalytic ozonation, the degradation of pharmaceutical compounds was performed using dawsonite-derived copper catalysts. The copper incorporated into the structure of dawsonite indicated higher activity in catalytic ozonation with respect to the calcined sample, soluble copper and aluminasupported copper oxide.

The objective of this thesis is contributing to the development of a systematic modelling approach for a more efficient and sustainable water management. The main aim is introducing Chemical and Process System Engineering methods and tools to provide a contribution to the AOPs (Advanced Oxidation Processes) investigation field by proposing process models that can be exploited to progress towards efficient management strategies for practical AOPs operation and inclusion in wastewater treatment networks. First, different advanced oxidation processes, namely Fenton, photo-Fenton and VUV photo-oxidation, were investigated and compared for the treatment of paracetamol (PCT) aqueous solution, by evaluating a series of performance indicators. Among the selected AOPs, VUV photo-oxidation and photo-Fenton showed the most promising results. Both processes allowed attaining total removal of the target compound and high mineralization levels. The second and main part of the thesis was focused on transforming “data into knowledge” by proposing different modelling approaches. The modelling effort focused on Fenton/photo-Fenton processes that showed the need of improving operating conditions. Accordingly, two practical kinetic models for Fenton and photo-Fenton degradation of organic compounds have been proposed and validated: • A conventional First Principles Model, based on a line source radiation model with spherical and isotropic emission, developed for the prediction of Fenton and photo-Fenton degradation of PCT and the oxidant (H2O2) consumption; • A general non-conventional First Principles Model, based on a wide-ranging contaminant degradation mechanism considering a variable number of carbon atoms for the characterization of the intermediates. Both models were experimentally validated and showed that were able to satisfactorily reproduce the system behavior. Particularly, the non-conventional First Principles Model showed to be a successful modelling approach for the Fenton/photo-Fenton degradation of different wastewater systems composed by single or multiple organic contaminants by means of lumped parameters (e.g. Total Organic Carbon-TOC). Thus, the approach proved to offer practical characterization of complex mixtures of chemicals. Once process models are proposed and validated, they can be systematically exploited to determine efficient operation modes or design alternatives. Accordingly, the thesis addressed two cases of practical interest: the optimization of a control recipe and the design of a treatment network. Particularly, a dynamic optimization framework for taking advantage of available kinetic models and determining the best hydrogen peroxide dosage profile, was proposed. Economic and environmental objectives and constraints were included to develop a dynamic optimization problem that was implemented in JModelica and solved using a direct simultaneous optimization method (IPOPT). Finally, the combination of cheaper conventional biological processes with more expensive AOPs was explored. A Mixed-Integer Non Linear Programming (MINLP) model for the optimization of a general wastewater network was proposed based on a superstructure of alternative designs, which was implemented and solved in GAMS. The novel formulation includes the BOD5/COD ratio method, describing the removal efficiency of BOD5 and COD of a treatment for modelling the variation of the biodegradability of the influents. This novel formulation allows determining the extent of the AOP treatments when combined with biological treatments, and paves the way for more complex models aimed at solving the trade-off between cost and treatment efficiency.
El objetivo de esta tesis es contribuir al desarrollo de técnicas de modelado sistemático para una gestión del agua eficiente y sostenible. El objetivo principal es contribuir a la investigación de los PAOs (Procesos Avanzados de Oxidación). La tesis introduce métodos y herramientas de Ingeniería de Procesos Químicos y propone modelos que puedan ser explotados para producir estrategias eficientes de gestión y operación de los PAOs, así como para la integración de estos PAOs en redes de tratamiento de aguas residuales. Primero, se investigaron diferentes PAOs. Se consideraron los procesos Fenton, foto-Fenton y la foto-oxidación VUV, y se compararon en el tratamiento de soluciones acuosas de paracetamol (PCT) adoptando una serie de indicadores de rendimiento (Key Performance Indicators, KPI). Entre los PAOs seleccionados, la foto-oxidación VUV y foto-Fenton producieron los resultados más prometedores, permitiendo lograr la eliminación total del contaminante y alto nivel de mineralización. La segunda parte de la tesis se centró en transformar ¿datos en conocimiento¿ mediante la propuesta de modelos para los procesos Fenton / photo-Fenton con el fin de mejorar las condiciones operativas de los mismos. En concreto se han propuesto y validado dos modelos cinéticos que describen la degradación de compuestos orgánicos por procesos Fenton y foto-Fenton: ¿ Un Modelo de Principios Básicos (F convencional, que incluye la modelización de la radiación lineal con emisión esférica e isotrópica, desarrollado para predecir la degradación Fenton y foto-Fenton del PCT y el consumo de oxidante (H2O2); ¿ Un Modelo de Principios Básicos no convencional, que propone un mecanismo de degradación de contaminantes general puesto que considera el número de átomos de carbono del contaminante como la variable de partida para la propuesta de fragmentación y consiguiente generación de intermedios. Ambos modelos se validaron experimentalmente y mostraron reproducir satisfactoriamente el comportamiento del sistema. En particular, el Modelo de Principios Básicos no convencional genero resultados prometedores para la degradación Fenton / foto-Fenton de diferentes sistemas (compuestos por uno o más contaminantes orgánicos) por medio de parámetros globales (como el Carbono Orgánico Total). Por tanto, este enfoque ofrece un modelado práctico independiente del contaminante y válido para mezclas complejas de productos químicos. Una vez propuestos y validados, los modelos de proceso se pueden utilizar sistemáticamente para determinar modos de operación eficientes o alternativas de diseño. En consecuencia, la tesis se dirigió a dos casos de interés práctico: la optimización de una receta de control y el diseño de una red de tratamiento. En el primer caso, se propuso una estrategia de optimización dinámica para aprovechar los modelos cinéticos disponibles y determinar el mejor perfil de dosificación de peróxido de hidrógeno. Se incluyeron objetivos y limitaciones económicas y ambientales para desarrollar un problema de optimización dinámica que se implementó en JModelica y se resolvió utilizando un método de optimización simultánea directa (IPOPT). Finalmente, se exploró la combinación de procesos biológicos convencionales, más baratos, con PAOs, más costosos. Se propuso un modelo de Programación no Lineal de Enteros Mixtos (MINLP) para la optimización de una red general de aguas residuales, basado en una superestructura de diseños alternativos, que se implementó y resolvió en GAMS. La nueva formulación incluye la relación BOD5 / COD, que describe la eficiencia de eliminación de BOD5 y COD de un tratamiento con el fin de modelar la variación de la biodegradabilidad de los influentes. Esta novedosa formulación permite determinar el alcance de los tratamientos de PAOs cuando se combinan con tratamientos biológicos, y allana el camino para modelos más complejos destinados a resolver el equilibrio entre coste y eficiencia del tratamiento.
L'objectiu d'aquesta tesi és contribuir al desenvolupament de tècniques de modelatge sistemàtic per a una gestió de l'aigua eficient i sostenible. L'objectiu principal és contribuir a la investigació dels PAOs (Processos Avançats d'Oxidació). La tesi introdueix mètodes i eines d'Enginyeria de Processos Químics i proposa models que puguin ser explotats per produir estratègies eficients de gestió i operació dels PAOs, així com per a la integració d'aquests PAOs en xarxes de tractament d'aigües residuals. Primer, es van investigar diferents PAOs. Es van considerar els processos Fenton, foto-Fenton i la foto-oxidació VUV, i es van comparar en el tractament de solucions aquoses de paracetamol (PCT) adoptant una sèrie d'indicadors de rendiment (Key Performance Indicators, KPI). Entre els PAOs seleccionats, la foto-oxidació VUV i foto-Fenton van produir els resultats més prometedors, permetent aconseguir l'eliminació total del contaminant i alt nivell de mineralització. La segona part de la tesi es va centrar en transformar "dades en coneixement" mitjançant la proposta de models per als processos Fenton / photo-Fenton amb la finalitat de millorar les condicions operatives dels mateixos. En concret, s’han proposat i validat dos models cinètics que descriuen la degradació de compostos orgànics per processos Fenton i foto-Fenton: • Un model de Principis Bàsics convencional, que inclou la modelització de la radiació lineal amb emissió esfèrica i isotròpica, desenvolupat per predir la degradació Fenton i foto-Fenton del PCT i el consum d'oxidant (H2O2); • Un model de Principis Bàsics no convencional que proposa un mecanisme de degradació de contaminants general, ja que considera el nombre d'àtoms de carboni del contaminant com la variable de partida per a la proposta de fragmentació i consegüent generació d'intermedis. Tots dos models es van validar experimentalment i van mostrar la seva capacitat de reproduir satisfactòriament el comportament del sistema. En particular, el Model de Principis Bàsics no convencional ha generat resultats prometedors per a la degradació Fenton / foto-Fenton de diferents sistemes (compostos per un o més contaminants orgànics) per mitjà de paràmetres globals (com el Carboni Orgànic Total). Per tant, aquest enfocament ofereix un modelatge pràctic, independent del contaminant i vàlid per a mescles complexes de productes químics. Un cop proposats i validats, els models de procés es poden utilitzar sistemàticament per determinar maneres d'operació eficients o alternatives de disseny. En conseqüència, la tesi es va dirigir a dos casos d'interès pràctic: l'optimització d'una recepta de control i el disseny d'una xarxa de tractament. En el primer cas, es va proposar una estratègia d'optimització dinàmica per aprofitar els models cinètics disponibles i determinar el millor perfil de dosificació de peròxid d'hidrogen. Es van incloure objectius i limitacions econòmiques i ambientals per desenvolupar un problema d'optimització dinàmica que es va implementar en JModelica i es va resoldre utilitzant un mètode d'optimització simultània directa (IPOPT). Finalment, es va explorar la combinació de processos biològics convencionals, més barats, amb PAOs, més costosos. Es va proposar un model de Programació No Lineal Entera Mixta (MINLP) per a l'optimització d'una xarxa general d'aigües residuals, basat en una superestructura de dissenys alternatius, que es va implementar i resoldre en GAMS. La nova formulació inclou la relació BOD5 / COD, que descriu l'eficiència d'eliminació de BOD5 i COD d'un tractament per tal de modelar la variació de la biodegradabilitat dels influents. Aquesta nova formulació permet determinar l'abast dels tractaments de PAOs quan es combinen amb tractaments biològics, i aplana el camí per a models més complexos destinats a resoldre l'equilibri entre cost i eficiència del tractament.
L'obiettivo della presente tesi è contribuire allo sviluppo di tecniche di modellizzazione sistematica finalizzate ad una gestione efficiente e sostenibile delle risorse idriche. L'obiettivo principale è contribuire allo studio dei POA (Processi di Ossidazione Avanzata). La tesi introduce metodi e strumenti dell’ingegneria dei processi chimici e propone modelli che possano servire per lo sviluppo di strategie efficaci di gestione dei POA nonché per l'integrazione di questi ultimi nelle reti di trattamento delle acque reflue. In primo luogo, sono stati studiati diversi POA. Nello specifico, sono stati studiati i processi di foto-ossidazione Fenton, photo-Fenton e VUV per il trattamento di soluzioni acquose di paracetamolo (PCT) la cui efficacia è stata confrontata adottando una serie di indicatori di prestazione (Key Performance Indicators, KPI). Tra i POA selezionati, la foto-ossidazione VUV e il processo photo-Fenton hanno prodotto i risultati più promettenti, consentendo di ottenere l'eliminazione totale del contaminante e un alto livello di mineralizzazione. La seconda parte della tesi si è concentrata sulla trasformazione dei "dati in conoscenza" proponendo modelli finalizzati alla descrizione dei processi Fenton / photo-Fenton e con l’obiettivo ultimo di adoperarli per ottimizzare le condizioni operative di questi ultimi. In particolare, sono stati proposti e validati due modelli cinetici che descrivono la degradazione dei composti organici per mezzo dei processi Fenton e photo-Fenton: • Un modello convenzionale, che include la modellizzazione della radiazione basata sull’ipotesi di radiazione lineare ed emissione sferica e isotropica, e in grado di prevedere la degradazione del PCT ad opera dei processi Fenton e photo-Fenton nonché il consumo di ossidante (H2O2); • Un modello non convenzionale, che propone un meccanismo generale di degradazione degli inquinanti basato sul numero di atomi di carbonio del contaminante da degradare a partire dal quale si propone un meccanismo di frammentazione di quest’ultimo con conseguente generazione di prodotti intermedi. Entrambi i modelli sono stati validati sperimentalmente e hanno mostrato prestazioni soddisfacenti. In particolare, il modello non convenzionale ha mostrato di poter rappresentare la degradazione Fenton e photo-Fenton di diversi composti organici attraverso l’utilizzo di un parametro globale (come il carbonio organico totale) e qindi di offrire una proposta di modellizzazione pratica indipendente dal contaminante e che può pertanto essere adottata in caso di miscele complesse di prodotti chimici. Una volta proposti e convalidati, i modelli di processo possono essere utilizzati sistematicamente per determinare modalità operative efficienti o alternative di progettazione. Di conseguenza, la tesi ha affrontato due casi di interesse pratico: l'ottimizzazione della ricetta di controllo del processo e la progettazione di una rete di trattamento di acque reflue. Nel primo caso è stata proposta una strategia di ottimizzazione dinamica per sfruttare i modelli cinetici disponibili e determinare il miglior profilo di dosaggio del perossido di idrogeno. Sono stati inclusi obiettivi e limiti economici e ambientali per sviluppare un problema di ottimizzazione dinamica implementato in JModelica che è stato risolto utilizzando un metodo di ottimizzazione simultanea diretta (IPOPT). Infine, è stata esplorata la combinazione di processi biologici convenzionali, più economici, con i PAO, più costosi. È stato proposto un modello MINLP (Nonlinear Mixed Integer Programming) per l'ottimizzazione di una rete di acque reflue, basato su una struttura attraverso la quale è possibile rappresentare scelte progettuali alternative, che è stato implementato e risolto in GAMS. La nuova formulazione include il rapporto BOD5 / COD, che descrive l'efficienza di eliminazione di BOD5 e COD di un trattamento al fine di modellare la variazione della biodegradabilità degli influenti. Questa nuova formulazione consente di determinare le diverse possibilità di combinazione dei PAO con i trattamenti biologici e apre la strada a modelli più complessi volti a risolvere l'equilibrio tra costo ed efficienza del trattamento.

Dairy manure treatment, using solid-liquid separation and microwave enhanced advanced oxidation process (MW/H₂O₂-AOP), was investigated. The objectives of the research were to determine: 1) the nutrient and metal composition of solid and liquid fractions of raw dairy manure following solid-liquid separation, 2) the effects of MW/H₂O₂-AOP operating factors of temperature, hydrogen peroxide (H₂O₂) dosage, acid concentration and heating time on sugar production and nutrient release from solid dairy manure. Solid-liquid separation of raw dairy manure, using a 1mm laboratory sieve, showed that solid fractions had a higher composition of TS and volatile solids (VS), while the liquid fractions were richer in nutrients and metals. Laboratory separation by screening alone was not effective in removing high amounts of nutrients and solids from the raw manure. Screening experiments were conducted using cellulose fibers to study the effects of temperature, acid concentration, H₂O₂ dosage and heating time on sugar production, with the aim of applying the results to dairy manure lignocellulosic material. Sugar production increased when acid concentration was increased from 1% to 3%, but decreased with an increase to 10%. More sugar was produced at 160°C compared to 120°C. Sugar production decreased with increasing time. Microwave irradiation of solid dairy manure at pH 2, temperatures of 80, 120 and 160°C, H₂O₂ dosages of 0 to 0.50 mL, and heating times of 10 to 20 min, showed that more sugars were released at higher temperatures. Temperature and hydrogen peroxide dosage were identified as the most important factors affecting solubilization of phosphorus and ammonia. Subsequently, a two-stage acid hydrolysis process, using MW/H₂O₂-AOP, was used to investigate sugar production and solubilization of phosphorus and ammonia from solid dairy manure at: 3% acid concentration, 120 and 160°C, 0 and 2 mL H₂O₂ and heating times of 20 and 60min. To enhance sugar production from solid dairy manure, the microwave should be operated at higher temperatures and shorter heating times with no H₂O₂. For ammonia and phosphorus solubilization, higher temperatures and longer heating times, in the presence of H₂O₂, would be advantageous. MW/H₂O₂-AOP is therefore an efficient means for treating diary manure for nutrient recovery.

Anaerobic digestion (AD) of dairy manure is an alternative to traditional manure management using land application. There are many benefits of AD but it is currently not an economically viable option in many parts of North America. The focus of this investigation was to determine whether liquid dairy manure treated by microwave hydrogen peroxide advanced oxidation process (MW/H₂O₂-AOP) would increase the anaerobic biodegradability of the substrate, producing higher methane yields. Biochemical methane potential (BMP) tests were conducted to measure biogas generation and the Modified Gompertz equation was used to determine the kinetics of anaerobic biodegradability. The research found that MW/H₂O₂-AOP was effective in solubilizing nutrients and organics in liquid dairy manure, but it does not necessarily translate into enhanced anaerobic biodegradability. The BMP tests revealed that digestion of untreated dairy manure at 35ºC had the highest methane yields. Severe inhibition was observed for the digestion of acidified dairy manure. This was attributed to sulfide inhibition. In addition, ammonia concentrations were suspected as the main reason for severe inhibition of microwave treated dairy manure with no acid addition, but a number of other factors could also be responsible, including sulfide, light metals and lack of temperature acclimation for inoculum. Pretreatment of sewage sludge and BMP tests were also conducted to compare the effect of MW/H₂O₂-AOP with dairy manure. The results showed that the microwave treatment had a positive impact on anaerobic digestibility of sewage sludge, especially for mesophilic digestion. At 35ᵒC, MW alone generated the highest methane yields followed by MW/H₂O₂ and then the control. In terms of methane yield, microwave treatment improved the methane production rate for mesophilic digestion, but not thermophilic digestion. The positive results for BMP tests of microwave treated sewage sludge suggest that the influence of microwave treatment on anaerobic biodegradability is substrate and solid concentration specific. There was no clear and consistent increase or decrease in soluble metal (Ca, K, Mg, Na) concentrations after MW/H₂O₂-AOP. However, it was found that acidified treatment was effective in releasing calcium and magnesium into solution. After digestion, the soluble calcium, potassium, magnesium and sodium content of dairy manure was reduced.

Ce travail de thèse contribue à la compréhension et au développement du procédé d’oxydation avancée couplant l’ozone et le peroxyde d’hydrogène (procédé peroxone O3/H2O2) en phase aqueuse. Ce procédé permet la génération de radicaux hydroxyles particulièrement réactifs et non sélectifs, capables de conduire à la minéralisation de nombreux polluants réfractaires. Dans un premier temps, la constante cinétique de la réaction entre l’ozone et l’anion hydroperoxyde, la base conjuguée de H2O2, a été déterminée entre 20 et 35°C par absorption réactive. Cette réaction joue un rôle primordial dans le procédé peroxone puisqu’elle permet d’initier la décomposition de l’ozone et donc la formation des premiers radicaux. Un réacteur à cellules agitées, dans lequel la phase liquide et la phase gazeuse sont séparées par une interface plane et horizontale, a ainsi été employé dans une configuration semi-continue. La valeur trouvée à 20°C a été comprise entre 1. 91×106 et 2. 40×106 L mol-1 s-1 selon la corrélation employée pour le calcul de la constante de Henry de l’ozone. Une énergie d’activation comprise entre 44,9 et 69,1 kJ mol-1 a ainsi été déterminée. Dans un second temps, un système innovant pour la mise en œuvre du procédé peroxone a été développé, en rupture avec la configuration traditionnelle du procédé dans lequel l’ozone est transféré directement dans la solution à traiter dopée en H2O2. Le procédé proposé repose sur une séparation des étapes de transfert de l’ozone et de mélange avec la solution à traiter dopée en H2O2. Ainsi, le transfert de l’ozone a été réalisé en continu en amont d’un réacteur tubulaire contenant des mélangeurs statiques employés pour réaliser en continu le mélange de la solution pré-ozonée et de la solution à traiter dopée en peroxyde d’hydrogène. La production radicalaire a ainsi été favorisée par des concentrations initiales d’ozone et de peroxyde d’hydrogène équimolaires. Dans ces conditions, l’ozone a été quasiment intégralement consommé au niveau du premier point de prélèvement, correspondant à un temps de réaction d’environ 10 à 20 s. Les résultats expérimentaux ont mis en évidence une exposition radicalaire de un à deux ordres de grandeur plus élevée que dans les applications classiques du procédé peroxone. Des ratios élevés de l’exposition aux radicaux hydroxydes sur l’exposition à l’ozone (Rct) proche de 10-6 ont été mesurés. Ainsi, cette configuration permet d’exploiter avantageusement les premières secondes de décomposition de l’ozone (phase initiale), au cours desquelles la production radicalaire est largement supérieure que dans la seconde phase de décomposition de l’ozone
This thesis work contributes to the understanding and the development of the advanced oxidation process coupling ozone and hydrogen peroxide (peroxone process O3/H2O2) in aqueous solution. This process allows the generation of non-selective and very reactive hydroxyl radicals, which can mineralize a lot of recalcitrant pollutants. In a first time, the reaction rate constant between O3 and the hydroperoxide anion, the conjugated base of H2O2, has been determined between 20 and 35°C by the reactive absorption method. This reaction plays a fundamental role in the peroxone process because it initiates the ozone decomposition and the first radicals’ formation. A stirred-cell reactor, in which the liquid and gas phases are separated by a flat interface, has been used semi-continuously. The reaction rate constant found at 20°C was in the range 1. 91×106 - 2. 40×106 L mol-1 s-1, depending on the correlation considered to calculate the ozone Henry’s law constant. Activation energy in the range 44. 9 - 69. 1 kJ mol-1 has been consequently determined. In a second time, an innovative system for the implementation of the peroxone process has been developed, breaking with the traditional peroxone process configuration in which the ozone is directly transferred in the treated water spiked with H2O2. The developed process is based on the separation of the ozone transfer in aqueous solution step and of the mixing with the treated water spiked with H2O2 solution steps. Thus, the ozone transfer was carried out continuously upstream of a tubular reactor filled with static mixers. This tubular reactor was used continuously to mix the pre-ozonated solution and the studied solution. The radical production was improved by using equimolar ozone and hydrogen peroxide concentrations. With these conditions, the ozone was almost fully consumed at the first sampling point, corresponding to a reaction time of around 10 to 20 s. The experimental results highlighted a hydroxyl radical exposure from one to two orders of magnitude higher than in the traditional peroxone process applications. High hydroxyl radical exposure to ozone exposure ratios (Rct), around 10-6, have been measured. Therefore, this configuration allows to advantageously benefit from the first seconds of the ozone decomposition (initial phase), in which the radical production is clearly higher than in the second phase of the ozone decomposition

Since the United States Environmental Protection Agency (USEPA) began requiring landfills to implement a leachate collection system in 1991, the proper disposal of leachate has become a growing concern. The potential toxicity of landfill leachate will contaminate groundwater and soil if not managed properly. Research has been made in efforts to manage leachate in a cost-effective, single treatment process. Photocatalytic oxidation is an advanced oxidation process (AOP) which has shown ability to reduce toxicity of an array of leachate constituents including organics, inorganics and heavy metals. The purpose of this manuscript is to scale up the batch scale study of TiO₂ photocatalytic degradation of leachate utilizing a pilot scale falling film reactor. In this research project, the use of UV/TiO₂ for the removal of chemical oxygen demand (COD), ammonia, alkalinity and color will be studied in order to optimize catalyst dosage, determine pH effects and reaction kinetics and develop preliminary cost estimates.

La escasez de agua se presenta como uno de los mayores retos para asegurar el desarrollo sostenible. Entre otras actuaciones, se deben investigar e implementar sistemas eficientes de tratamiento de aguas biorecalcitrantes, que necesitan ser condicionadas antes de su depuración biológica. Uno de los posibles pre-tratamientos es el proceso Fenton de oxidación avanzada, que presenta dos principales inconvenientes: la utilización de sales de hierro como catalizador homogéneo, que abandonan continuamente la etapa de oxidación, y el elevado consumo de oxidante, en parte desaprovechado. La presente tesis se centra en el estudio de la mejora del proceso Fenton de aguas fenólicas mediante su acoplamiento con tecnologías de membrana como la nanofiltración, la emulsificación con membranas o los reactores de membrana. El acoplamiento de dichas tecnologías con el proceso Fenton permite el confinamiento del catalizador y el aumento de la eficiencia de oxidación, mejorando así el tratamiento en términos ambientales y económicos.
Water scarcity is one of the major challenges for assuring a sustainable development. Among other measures, research into efficient wastewater treatment systems to deal with biorefractory wastewaters, which need to be amended before their biological degradation, is required. The Fenton process is an advanced oxidation process that can be used as potential pre-treatment for this purpose. However, the pre-treatment presents two main limitations: the use of iron salts as homogeneous catalyst, which are continuously thrown away in the reactor effluent, and the high consumption of oxidant, which is partially wasted. The present thesis aims at studying the improvement of the Fenton process applied on phenolic wastewater through its coupling with membrane technologies such as nanofiltration, membrane emulsification or membrane reactors. The coupling allows confining the catalyst and increasing the oxidation efficiency, thus enhancing the treatment efficiency in environmental and economic terms.

Philosophiae Doctor - PhD
Emerging micropollutants such as bisphenol-A and 2-nitrophenol present a great threat in drinking water due to their adverse effects. Most conventional technologies in water and wastewater treatment are not designed to eliminate these xenobiotics; instead pollutants are merely transferred from one phase to another. Advanced oxidation technologies (AOTs) however, have been identified as suitable routes for the degradation of these potential damaging substances based on free radical mechanisms and use of less expensive chemicals. Moreover, due to the structural complexity of wastewater and the existence of pollutants as mixtures, no single advanced oxidation technology can convincingly remove all forms of contaminants and then most often than not, a combination of treatment processes is required for an effective purification process. Besides, the problem of adequate degradation of emerging contaminants in the environment, when AOT(s) are used individually, they present inherent problems. For instance, powder TiO₂ photocatalysts obstruct light penetration, thus prevent effective interaction of UV light with the target pollutants, and particulates present problems of post-filtration and recovery of catalyst particles after treatment. Additionally, TiO₂ has a high band gap energy, high electron-hole recombination rate, and is prone to aggregation of the suspended particles. Similarly, the dielectric barrier discharge (DBD) system produces ultra violet light and hydrogen peroxide within the plasma zone which is not fully maximised for the mineralization of persistent organic pollutants. Rapid oxidation and aggregation of nano zero valent iron particles in photo-Fentons process reduce the particles mobility and affect its performance. In the same vein, the jet loop reactor (JLR) system is characterised by low impingement yield, which is responsible for low mineralization rate. In light of this background, this research investigated the degradation of bisphenol-A and 2- nitrophenol in aqueous solution using the following combined advanced oxidation methods: DBD/supported TiO₂ or Ag doped TiO₂ photocatalysts, DBD/photo-Fenton induced process and JLR/UV/H₂O₂. The target was to assess the performance of each single system and then identify the best combined AOTs capable of significantly mineralizing the target compounds. Firstly, two materials were developed namely supported TiO₂ and stabilized nano zero valent Fe. The TiO₂ photocatalyst supported on a stainless steel mesh was synthesised using sol-gel solution of 8 % PAN/DMF/TiCl₄. The influence of calcination temperature and holding time on the formation of nanocrystals was investigated. Afterwards, various amounts of metallic silver were deposited on the (optimum) supported TiO₂ photocatalyst using thermal evaporation. The catalysts were characterized by several analytical methods; HRSEM, HRTEM, EDS, SAED, FTIR, TGA-DSC, UV-vis/diffuse reflectance spectroscopy, XRD, BET, and XPS. The photocatalytic activity of the prepared catalysts was determined using methylene blue as a model pollutant under ultra-violet light irradiation. Secondly, the TiO2 photocatalyst and 2.4 % Ag doped TiO₂ nanocomposites obtained as optimums (in section 1) were combined with the DBD to decompose BPA or 2-NP in aqueous solution. Moreover, the photo-Fenton process was applied for degradation of the model pollutants, and different dosages of stabilized nZVI (in the range of 0.02 -1.00 g) were added to the DBD system to induce the photo-Fenton process and improve BPA or 2-NP degradation efficiency. Finally, a jet loop reactor (JLR) presenting advanced mixing by the “impinging effect” was explored to decompose BPA or 2-NP in aqueous solution as a function of inlet applied pressure, solution pH, and initial concentration of BPA or 2-NP. Subsequently, different concentrations of hydrogen peroxide (H₂O₂) were added to the JLR to enhance the mineralization process. Furthermore, a combination of JLR with in-line UV light and H₂O₂ were further utilised to decompose BPA or 2-NP in aqueous solution. The residual concentration of the model compounds and intermediates were analysed using high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LCMS). The concentration of the ozone, hydrogen peroxide and hydroxyl radicals generated by the DBD in the presence or absence of a catalyst was monitored using Ultraviolet-visible spectroscopy and Photoluminescence spectroscopy. The results revealed that the optimal thermal conditions to obtain well supported uniformly grown, highly active crystalline TiO₂ catalysts with high specific surface area was 350 ºC at a 3 h holding time in N2 atmosphere with a flow rate of 20 mL/min. Pyrolysis temperature and holding time played an important role on the crystalline nature and photocatalytic activity of the catalyst. Moreover, 2.4 % Ag doped TiO₂ nanocomposites exhibited higher photocatalytic activity for methylene blue degradation than the undoped supported TiO₂ nanocrystals. The results indicated that combining DBD with 2.4 % Ag doped TiO₂ nanocomposites achieved 89 % and 81 % removal efficiency for BPA or 2-NP compared to 67.22 % or 56.8 % obtain when using the DBD system alone. The 2.4 % Ag doped TiO₂ nanocomposites demonstrated excellent activity and offered photochemical stability after four repeated applications.In the case of the photo-Fenton induced process, nano zero valent iron particles (nZVI) stabilized with polyethylene glycol were synthesised using a modified borohydride reduction method. The HRSEM, BET, XRD, and XPS analysis confirmed the formation of filamentous, high surface area iron nanoparticles in the zero valent state. Unlike combined DBD/Ag doped TiO2 nanocomposites, 100 % or complete removal of BPA or 2-NP in aqueous solution was achieved with DBD/nZVI system within 30 minutes compared to 67.9 % (BPA) or 56.8 % (2-NP) with DBD alone after 80 minutes. The removal efficiency was attributable to the production of an increased concentration of OH radicals as well as existence of a synergetic effect in the combined DBD/nZVI system. Five new transformation products namely: 4-nitrophenol (C₆H₅NO₃), 4-nitrosophenolate (C₆H₄NO₂), 4-(prop-1-en-2-yl) cyclohexa-3,5-diene-1,2-dione, (C₉H₈O₂), 4-(2- hydroxylpropan-2-yl)cyclohexane-3,5-diene-1,2-dione (C₉H₁₀O₃), and 1,2-dimethyl-4-(2- nitropropan-2-yl)benzene (C₉H₁₀NO₄) were identified during the degradation of BPA. While, three aromatic intermediate compounds such as 2-nitro-1,3,5-benzenetriolate (C₆H₂NO₅), 2- nitro-1,4-benzoquinone (C₆H₃NO₄), and 2,5-dihydroxyl-1,4-benzoquinone (C₆H₄O₄) respectively were identified during the degradation of 2-NP for the first time in the DBD with JT14 or JT17 using LC-MS. These intermediate compounds have never been reported in the literature, thereby expanding the number of BPA or 2-NP intermediates in the data base in the DBD/JT14 or DBD/nZVI system. BPA degradation proceeded via ozonation, hydroxylation, dimerization, and decarboxylation and nitration step, while 2-NP proceeded via hydroxylation, nitration and denitration respectively. Furthermore, maximum removal efficiency of BPA or 2-NP in aqueous solution using JLR alone under the optimum solution pH (3), inlet pressure (4 bar), flow rate (0.0007 m3/s) was 14.0 % and 13.2 % respectively after 80 minutes. A removal efficiency of 34.9 % was recorded for BPA while 33.2 % was achieved for 2-NP using combined JLR/UV under the same conditions as JLR alone. For the combined JLR/H₂O₂ under optimum conditions of inlet pressure (4 bar), solution pH (3) and peroxide dosage (0.34 g/L), a 51.3 % and 50.1 % removal efficiency was achieved for BPA and 2-NP respectively under same conditions relative to JLR alone. Combination of JLR/UV/H₂O₂ achieved 77.7 % (BPA) or 76.6 % (2- NP) removal efficiency under the same conditions. The combined JLR/UV/H₂O₂ process was found to be most effective combination under the optimized operating parameters due to existence of a synergetic index value of 6.42 or 6.84. This implies that JLR should be coupled with UV and H₂O₂ to achieve greater mineralization efficiency instead of using the system individually. The obtained experimental data of these combined treatment processes fitted the pseudo-first order kinetic models. The combination of the JLR/UV/H₂O₂ was found to be energy efficient and could effectively degrade BPA or 2-NP in aqueous solution to a greater extent than the JLR, JLR/UV or JLR/H₂O₂ system. However, the total organic carbon (TOC) reduction value by all combined DBD and JLR system recorded was not completely achieved due to the formation of recalcitrant intermediate compounds under the applied conditions. In conclusion, this study is reporting for the first time a combination of supported 2.4 % Ag doped TiO₂ nanocomposites with dielectric barrier discharge system for BPA/2-NP degradation in aqueous solution; a combination jet loop reactor based on impingement with in-line UV lamp and H2O2 for successfully decomposing BPA or 2-NP in aqueous solution; as well as a combination of dielectric barrier discharge system and stabilised nano zero valent iron particles, which induced a photo-Fenton process for highly effective removal of BPA or 2-NP in aqueous solution. This study conclusively supports the hypothesis that combined advanced oxidation technologies offer a sustainable and highly efficient means of achieving partial or complete removal of BPA or 2-NP in aqueous solutions. Considering all the combinations of AOTs investigated in this study, the novel DBD/photo-Fenton-induced process under optimised operating parameters was found to be the most efficient in the elimination of BPA or 2-NP in aqueous solutions. The combination of DBD with photo- Fenton like process offers a promising advanced waste water purification technology in the immediate future. Based on these findings, it is recommended that DBD should be redesigned to prevent loss of ozone and JLR system reconfigured to increase impingement and cavitational yield in order to have an effective combination treatment strategy for waste water purification especially in large scale waste water management.
National Research Foundation (NRF) and Water Research Commission, South Africa

Thesis (MEng (Chemical Engineering))--Cape Peninsula University of Technology, 2020
Reactive dye waste effluents are the most difficult to treat, as they are highly polluted due to the structure of the dyestuffs and chemicals used during the dyeing process. Due to the water shortage and environmental pollution, textile industries are encouraged to treat the waste effluent produced during dyeing processes so as to facilitate its reuse, as this will contribute to mitigating environmental pollution and minimise water consumption. However, relatively few of the treatment technologies employed for the treatment of textile wastewater are applicable for water that is intended for reuse. Many treatment technologies exist for the treatment of textile waste effluents, but are either limited in efficiency or high in operating and energy cost. Chemical treatment methods such as the cobalt oxide mediated sulphate radical-based advanced oxidation process (CO-SR-AOP) shows promise but have not yet been evaluated for the reuse of textile wastewater in the dyeing process. The purpose of this work is to study the reusability of a treated reactive dye effluent obtained from dyeing cotton fabrics using peroxymonosulfate (PMS) activated by a cobalt oxide (Co3O4) catalyst and using a laboratory-scale continuous wastewater treatment reactor. In order to achieve this, a cobalt oxide catalyst was hydrothermally synthesised, cotton fabrics were bleached as pre-treatment prior to being dyed using blue reactive dye and tap water to produce the necessary textile waste effluent. The produced waste effluent was treated with Oxone (PMS) and a cobalt oxide catalyst; then reused in the next dyeing process, using an identical dyeing recipe. The pH of the treated effluent was corrected to neutral before its reuse. The waste effluent from the first cycle of dyeing was treated before its next reuse. This process was carried out for a maximum of three cycles. The dyed fabrics obtained using the treated effluent were compared with the ones dyed with tap water in terms of colour fastness. The optimisation of the reusability of a treated effluent from cobalt oxide and sulphate radical-based advanced oxidation process was carried out using Design-Expert software version 11.1.2.0 using a Box-Behnken design taken from response surface methodology. The effects of three factors were studied: Oxone level, dye concentration and reuse cycles at low, high and medium levels in fifteen experimental runs. Colour fastness of the dyed fabrics was studied as the response of the trials. Based on the preliminary results, the treated effluent can be reused in two successive reuse cycles without altering the fabric’s quality. To obtain more or less 80% colour removal, waste effluent with 3% dye concentration must be obtained and treated with a high dosage of Oxone (3.5 g/l). Salt can be recovered by using this process, but with a darker shade of dyed fabric as a result, when compared with the reference. Varying dilution factors and standing times of the treated effluent were investigated but did not have significant influence on the colour quality of the dyed fabrics. A useful model was found to predict the colour fastness of dyed fabrics with an effluent treated with the continuous wastewater treatment reactor system using PMS activated by Co 3 O 4 . The study of the interaction effects of all three parameters led to the finding that to obtain good colour fastness grading of the dyed fabrics, the treated effluent can be reused a maximum of two iterations, with a dye concentration of 5% and an Oxone concentration of 1 g/L. The predicted optimum process conditions for this process were 1.3 g/l of Oxone used to treat a waste effluent with 4.4% dye concentration and reuse in a maximum of three reuse cycles.

This research involved an investigation of the application and reaction mechanisms of UV/H₂O₂ for the simultaneous removal of regulated halogenated disinfection byproducts (DBPs) and odorous aldehydic algal byproducts in the presence of geosmin and 2-methylisoborneol, which are earthy-musty odorants that commonly occur in drinking water. UV/H₂O₂ is an expensive advanced oxidation process that is used to successfully control geosmin and 2-methylisoborneol. The aqueous oxidation of odorous aldehydes and halogenated DPBs were compared to that of the earthy-musty odorants and the changes to the sensory properties of the drinking water were examined. Geosmin, 2-methylisoborneol, heptadienal, decadienal, and nonadienal, hexanal, and the two most prevalent classes of DBPs, trihalomethanes (THMs) and haloacetic acids (HAAs) were oxidized by UV photolysis alone and the UV/H₂O₂ process with 6 mg/L H₂O₂ and realistic ng/l to μg/L concentrations of the test compounds. The di-, and tri-brominated THMs and HAAs were substantially (80-99%) removed by direct UV photolysis mechanism at the same UV/H₂O₂ dose required for removing 95% of geosmin and 65% of 2-methylisoborneol with faster reaction rates for the more bromine substituted compounds. The C-Br bond cleavage is the first step of brominated HAAs degradation by UV photolysis, and followed by either of two second steps: reaction with oxygen producing peroxyl radical or interaction with water molecule causing O-H insertion/H-Br elimination. Trichloromethane and mono-, di-, and tri-chlorinated HAAs were not substantially removed under the same conditions used for the brominated compounds. The principal removal mechanism was by the reaction with hydroxyl radical for the UV/H₂O₂ process. The second order reaction rate constants were on the order of 10⁶ - 10⁸ M⁻¹ s⁻¹ with faster reaction rates for the less chlorine substituted compounds. Based on the reaction rates, hydrogen and halogen ion balance, and isotope effect, both hydrogen abstraction and electron transfer reaction were involved in the first steps of the chlorinated HAA degradation. Three odorous aldehydes - heptadienal, decadienal, and nonadienal - were removed faster than geosmin or 2-methylisoborneol, and direct UV photolysis was the principal reaction mechanism for the removal of these unsaturated aldehydes. Hexanal was poorly removed. In sensory tests, new odors such as sweet or chalky odors were produced while the concentration and initial odor intensity of these fishy/grassy-smelling aldehydes were reduced with increasing exposure time to UV/H₂O₂. Carbonyl compounds were detected as products of the UV photolysis of nonadienal. These carbonyls were not removed by further UV irradiation, which was thought to be partially related with production of new odors. The results indicate that the UV/H₂O₂ is effective to control both odorous compounds and brominated DBPs. This process can be seasonally applied to control both contaminants especially, in the warm summer when both odorants and DBPs have their higher concentrations. Removal of brominated DBPs can be a significant addition to water utilities that have difficulty in meeting regulatory levels for these highly toxic compounds. The result on the removal of odorous aldehydes indicate that new types of odors were produced from the oxidation of odorous aldehydes suggesting sensory test coupled with chemical analysis should be considered in designing oxidation process to control recalcitrant odorants.
Ph. D.

Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016.
The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.

The future hydrogen demand is expected to increase, both in existing industries (including upgrading of fossil fuels or ammonia production) and in new technologies, like fuel cells. Nowadays, hydrogen is obtained predominantly by steam reforming of methane, but it is well known that hydrocarbon based routes result in environmental problems and besides the market is dependent on the availability of this finite resource which is suffering of rapid depletion. Therefore, alternative processes using renewable sources like wind, solar energy and biomass, are now being considered for the production of hydrogen. One of those alternative methods is the so-called “steam-iron process” which consists in the reduction of a metal-oxide by hydrogen-containing feedstock, like ethanol for instance, and then the reduced material is reoxidized with water to produce “clean” hydrogen (water splitting). This kind of thermochemical cycles have been studied before but currently some important facts like the development of more active catalysts, the flexibility of the feedstock (including renewable bio-alcohols) and the fact that the purification of hydrogen could be avoided, have significantly increased the interest for this research topic. With the aim of increasing the understanding of the reactions that govern the steam-iron route to produce hydrogen, it is necessary to go into the molecular level. Spectroscopic methods are an important tool to extract information that could help in the development of more efficient materials and processes. In this research, ethanol was chosen as a reducing fuel and the main goal was to study its interaction with different catalysts having similar structure (spinels), to make a correlation with the composition and the mechanism of the anaerobic oxidation of the ethanol which is the first step of the steam-iron cycle. To accomplish this, diffuse reflectance spectroscopy (DRIFTS) was used to study the surface composition of the catalysts during the adsorption of ethanol and its transformation during the temperature program. Furthermore, mass spectrometry was used to monitor the desorbed products. The set of studied materials include Cu, Co and Ni ferrites which were also characterized by means of X-ray diffraction, surface area measurements, Raman spectroscopy, and temperature programmed reduction.

Ozonation is an integral process in ozone-biofiltration treatment systems and is beginning to be widely adopted worldwide for water reuse applications. Ozone is effective for pathogenic inactivation and organics oxidation: both increasing assimilable organic carbon for biofiltration and eliminating trace organic contaminants which may pose a threat to human health. However, ozone can also form disinfection byproducts such as bromate from the oxidation of naturally occurring anion bromide. Bromate is a known human carcinogen and is regulated by the EU, WHO, and USEPA to a maximum limit of 10µg/L. In waters high in bromide, especially above 100µg/L, bromate formation becomes a major concern. In the secondary wastewater effluent studied, bromide concentration may exceed 500µg/L. Several bromate suppression techniques have been devised in previous work, including free ammonia addition, monochloramination, and the chlorine-ammonia process. While free ammonia addition was not found to adequately reduce bromate formation below the required MCL, monochloramine addition and the chlorine-ammonia process were found to be effective. However, the impact of these chemical suppression techniques on organics oxidation and disinfection has not been fully studied. This study explored the impact of these bromate suppression techniques at a wide range of ozone doses on bromate formation, pathogenic inactivation, ozone-refractory organics oxidation through the surrogate 1,4-dioxane, and N-nitrosodimethylamine (NDMA) formation. Additionally, bromate suppression mechanisms of monochloramine were explored further through a variety of different water quality parameters, such as through hydroxyl radical exposure and ultraviolet absorption spectrum measurements, which were correlated and utilized to develop a hydroxyl radical exposure predictive model.
Master of Science
Ozone is a powerful oxidant used in water treatment in order to degrade contaminants of emerging concern into less harmful moieties and to inactivate pathogens. Upon application to process water, ozone quickly reacts with constituents in the water to form hydroxyl radicals: the most powerful oxidant in water treatment. These hydroxyl radicals, though with extremely short half-lives, are able to degrade ozone-recalcitrant organics, such as 1,4-dioxane through a process called advanced oxidation. Ozone itself also has the capability of inactivating a multitude of pathogenic organisms, including viruses Giardia and Cryptosporidium parvum when specific contacts times are met. However, ozone does have the potential to form disinfection byproducts such as Nnitrosodimethylamine (NDMA) and bromate. NDMA, though not currently regulated by the United States’ Environmental Protection Agency (USEPA), has a drinking water health advisory limit of 10ng/L in the State of California. Bromate, on the other hand, is a known human carcinogen regulated to 10µg/L by the USEPA. Formed within the ozone system from the naturally occurring ion bromide, bromate can be limited through various chemical treatments such as ammonia addition, pH adjustment, monochloramination, and the chlorine-ammonia process. To date, these methods of bromate suppression have not been comprehensively studied in terms of bromate suppression as well as disinfection and organics oxidation in water reuse systems. The purpose of this research was to minimize bromate formation while ensuring NDMA formation was minimized, and disinfection and organics oxidation were maximized. Through this study, system efficiencies were improved and water quality for future generations will be improved.

Wastewaters from textile industry contain organic dyes, which cannot be easily treated by biological methods. Therefore, pretreatment by an advanced oxidation process (AOP) is needed in order to produce more readily biodegradable compounds and to remove color and chemical oxygen demand (COD) simultaneously. In this research, ozone (O3) is combined with hydrogen peroxide (H2O2) for the advanced oxidation of an azo dye solution, namely aqueous solution of Acid Red 151, which is called as &ldquo
Peroxone process&rdquo
. The aim of the study is to enhance the ozonation efficiency in treating the waste dye solution. The effects of pH, initial dye and initial ozone concentrations and the concentration ratio of initial H2O2 to initial O3 on color and COD removals were investigated. Also, the kinetics of O3-dye reaction in the presence of H2O2 was approximately determined. As a result of the experimental study, it was seen that an increase in the initial dye concentration at a constant pH and initial ozone concentration did not change the COD % removal significantly, from a statistical analysis of the data. The results obtained at pH values of 2.5 and 7 gave higher oxidation efficiencies in terms of color and COD removals compared to those at pH of 10. The best initial molar ratio of H2O2 to O3 was found to be 0.5, which yielded highest treatment efficiency for each pH value studied. The results of the excess dye experiments suggest that the ozonation of Acid Red 151 follows an average first order reaction with respect to ozone at pH=2.5 and pH=7 whereas it is around 0.56 at pH=10. By Initial Rate Method, the orders with respect to individual reactants of O3 and dye were determined as one, the total order of the reaction being two for all the studied pH. As a conclusion, a further study of the peroxone process at a pH of 10 can be recommended to determine the reaction kinetics and mechanism at this pH, where radicals play an important role.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.
Includes bibliographical references (leaves 96-97).
In this work, the issue of how to remove phosphate esters from drinking water is examined. From the various treatment processes available, the oxidation of phosphate esters through hydroxyl radical generated by the UV/H202 process applied at a UV disinfection unit was selected for evaluation. The second-order rate constants of the reactions of two phosphate esters, Tri(2-butoxyethyl) phosphate (TBEP) and Tri-2-chloroethyl phosphate (TCEP) , with hydroxyl radical were estimated from our experimental data to be 2.1000 M-1s-1 and 2 109 M-is-1 respectively A comprehensive kinetic model of the oxidation process was derived. Finally computer simulations were used to exhibit the potential of this treatment process and to examine the effects of pH, total carbonate species concentration, initial hydrogen peroxide dose, and light intensity on its efficiency. The results are not very encouraging when a UV unit designed for disinfection is used. For typical values of pH and total carbonate species (pH=8 and CT=5' 10-4 M) the 1 s order rate coefficients for removal of the phosphate esters are 6.3 10-4 (s-1) for TBEP and 6.3 10-5 (s-1) for TCEP. If higher light intensity is applied in the reactor (50 times higher), and initial hydrogen peroxide dose of 10-3 M and CT remains 5 10-4 M, the 1st order reaction rate coefficients become 2.9 10-2 (s-1) and 2.9-10-3 (s-1) for TBEP and TCEP respectively.
by Alexandros Machairas.
M.Eng.

The present study is aimed to analyse the degradation of caffeine in water employing an advanced oxidation process, the photo-Fenton reaction (H2O2/Fe2+/UV). Different concentrations of H2O2 and Fe2+ are used to evaluate the effects of the two reagents on the quality of the water after the reaction and on the kinetics of degradation. The quality of the water is estimated in terms of conductivity, turbidity, colour and aromaticity. These quantities were found to be not dependent on H2O2 concentrations, whereas the Fe2+ concentration affects them in a proportional way. Compared to the limits of European Directives, the resulting conductivity is acceptable. Turbidity and colour exceed the limits, and the observed influence of the catalyst suggests that they are due to iron species, not to reaction products. Finally, the method employed to evaluate the aromaticity, based on absorbance at 254 nm, does not seem to be reliable. The kinetics of degradation are elaborated through measurements of the absorbance at 272 nm as a function of time. The dependence of the reaction rate on H2O2 concentration observed here is small, but even the lowest concentration employed is 16 times larger than that of caffeine. When the H2O2 concentration is kept constant, a nearly direct proportionality results between reaction rates and Fe2+ doses. Further analyses have shown that caffeine can also be degraded only under UV-visible irradiation (no reagents), but the reaction would need a very long time (6% in 45 minutes). With the addition of Fe2+ (without H2O2) the reaction rate was found somewhat higher, while with the addition of only H2O2 (without Fe2+) the photo-degradation rate was found to be 2/3 of that measured using both reagents. Therefore, the Fe2+ catalyst contributes to the degradation, but dissociation of the perossidic O-O bond of H2O2 to give OH• radicals can also be directly caused by UV irradiation.

Vacuum-UV Advanced Oxidation Process (AOP) has been identified as a viable candidate to treat chemical contaminants in drinking water. In contrast to the commercially available and widely applied UV/H₂O₂ AOP, VUV AOP does not rely on the addition of chemicals for the generation of hydroxyl radicals. As a result, the technology is very appealing to small systems and rural communities which often lack infrastructure and qualified personnel to operate complex systems. The primary objective of this research was to investigate the effect of temperature on the removal efficiency and energy consumption of a UV/VUV flow-through photoreactor. Additionally, the optical absorption properties at 185 nm of water and naturally occurring solutes such as Natural Organic Matter (NOM), nitrate, sulphate and chloride were studied between 3.6 and 25.0 °C. The secondary objective of this research was to investigate the effect of UV/VUV treatment on the removal of a mixture of micropollutants (e.g., pharmaceuticals, hormones, pesticides). The results showed that temperature does not have a significant impact on process efficiency and energy consumption. Moreover, owing to the presence of naturally occurring solutes, it was found that the production of OH radicals was to some extent limited at 3.6 °C, therefore slightly lower removals were observed at low temperature. When evaluated on a mixture of micropollutants, the UV/VUV process could potentially degrade a variety of substances with feasible energy consumption. Other than for two of the 12 micropollutants tested, at a flow-rate of 1.9 L min-¹, the VUV process was competitive to the UV/H₂O₂ process.
Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate

La pollution des ressources en eau est un des défis importants auquel les Hommes doivent faire face. En particulier, de nouvelles solutions doivent émerger, puisque les techniques conventionnelles de traitement utilisées actuellement ne permettent pas une élimination efficace des divers polluants. Parmi les polluants émergents, les composés pharmaceutiques ont récemment été détectés dans différentes sources d'eau à travers le monde. Leurs effets indésirables sur l'environnement naturel et sur l'Homme ont déjà été reconnus mais doivent encore être éclaircis. De nombreux nouveaux procédés de traitement de l'eau apparaissent. En particulier, le procédé électro-Fenton a démontré sa capacité à éliminer les pharmaceutiques et autres contaminants persistants. Ce procédé est basé sur la génération in-situ d'une espèce oxydante très puissante, les radicaux hydroxyles (OH), qui permettent la dégradation non-sélective des polluants. Cependant, cela nécessite l'utilisation d'une quantité d'énergie importante, relativement coûteuse. Une solution viable est de coupler le procédé électro-Fenton avec un procédé biologique. En effet, l'utilisation de ce dernier est beaucoup plus économique, mais il possède une efficacité limitée envers les polluants persistants tels que les pharmaceutiques. Ainsi, le procédé hybride bio-électro-Fenton apparaît comme un bon compromis entre le coût et l'efficacité. Le but de cette thèse de doctorat a donc été d'optimiser le procédé électro-Fenton dans l'optique de le coupler avec un procédé biologique, afin d'éliminer les pharmaceutiques. Les principaux objectifs de cette étude reposent sur l'étude de l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton sur (a) la dégradation des pharmaceutiques ; (b) la minéralisation de la matière organique ; (c) l'évolution de la biodégradabilité; (d) la consommation énergétique. Cette thèse est composée de trois parties, au cours desquelles la complexité des solutions traitées a progressivement augmentée. Premièrement, une étude a été menée sur des solutions de produits pharmaceutiques seuls afin de mieux comprendre les mécanismes impliqués au cours de leur dégradation. La seconde partie porte sur l'étude expérimentale d'une solution synthétique composée d'un mélange de 13 pharmaceutiques. La dernière étape a consisté à mettre en place un procédé bio-électro-Fenton pour le traitement d'un effluent pharmaceutique réel. Cette démarche progressive a permis de mieux comprendre l'influence des paramètres opératoires utilisés au cours du procédé électro-Fenton. Les principaux résultats obtenus sont notamment l'optimisation de deux paramètres opératoires important : la concentration du catalyseur (Fe2+) et l'intensité du courant. L'influence de ces paramètres s'est révélée similaires au cours du traitement de tous les types de solution testée. Il a donc été possible de conclure que les valeurs optimales sont une concentration en Fe2+ de 0,2 mM et une intensité entre 100 et 500 mA. L'efficacité d'élimination des pharmaceutiques a été plus importante en utilisant des intensités plus faibles (100-300 mA). Cependant, la biodégradabilité de l'effluent, un paramètre important dans l'optique du post-traitement biologique, a été d'avantage augmentée en utilisant des intensités élevées (500-1000 mA). Par ailleurs, l'utilisation d'intensités élevées a aussi mené à augmenter la consommation énergétique, en particulier dans le cas de temps de traitement longs. Il apparaît donc évident qu'un compromis entre efficacité et consommation énergétique doit être trouvé pour chaque cas particulier et effluent à traiter. Pour conclure, les avancées de cette recherche sont principalement attribuées à la nouveauté de la combinaison bio-électro-Fenton. L'étude de l'influence des paramètres opératoires du procédé électro-Fenton a aussi permis d'améliorer la compréhension de cette nouvelle technique et contribue à son développement vers une application industrielle
Water pollution is one of the biggest challenges that humanity faces and combating it requires the development of treatment processes, as conventional methods used nowadays are no longer effective for the removal of various complex pollutants. Recently pharmaceuticals have been recognized to be contaminants of emerging environmental concern as their traces were detected in a spectrum of water bodies around the globe. The long term effects of their presence in a natural environment are not yet fully studied, but the potential outcomes can be detrimental to a sustainable future. Among the variety of currently rising treatment technologies, the electro-Fenton method, an electrochemical advanced oxidation process, has demonstrated an ability to eliminate pharmaceuticals as well as other types of persistent contaminants. This electrocatalytical process generates in situ strong oxidants species - hydroxyl radical (OH) - which non-selectively degrade organic pollutants. Due to the extensive cost in the application of electrical energy, its operation might be cost-prohibitive. A solution would be to combine it with biological processes which are more economically viable, but also less effective in the removal of pharmaceuticals. The combined process is expected to have a synergetic effect between cost and effectiveness. The goal of this PhD thesis is to optimize operating conditions of the electro-Fenton process for a feasible combination with a biological process as a means of treating pharmaceutical pollution. The main objectives addressed by this work are related to the influence of operating parameters of the electro-Fenton process on (a) removal of pharmaceuticals; (b) mineralization of organic matter; (c) enhancement of biodegradability; (d) energy consumption. The thesis has three distinct parts related to the type of treated aqueous solution. First, a mechanistic study was conducted on aqueous solutions of individual pharmaceuticals in order to understand general trends of their removal. Next, a series of experiments was carried out on a synthetic mixture of thirteen pharmaceuticals from different therapeutic classes. Lastly, laboratory bench-scale reactors of a combined bio-electro-Fenton process were operated for the treatment of real wastewater. The advance in the complexity of the treated solution allowed a comprehensive comparison and analysis of the influence of the operating parameters. The main results include the optimal values of two operating parameters: the catalyst (Fe2+) concentration and the applied current intensity for a given electro-Fenton setup. The effects of the operating parameters on the removal of pharmaceuticals and other organic matter were similar regardless of the treated solution. The optimal value for the Fe2+ concentration was concluded to be around 0.2 mM. The optimal current intensity was in the range 100-500 mA. The efficiency of the current in terms of the pharmaceuticals' removal was the highest with the lowest intensity (100-300 mA). At the same time the biodegradability, which was an important factor in the biological post-treatment process, improved with higher intensities of electric current (500-1000 mA). However, high current intensities resulted in an elevated energy consumption, particularly with a prolonged treatment time. A tradeoff would have to be consequently made between energy saving and the removal rates that should be found in any single case. The novelty of the research presented in this PhD thesis is firstly attributed to the novelty of the combination of electro-Fenton to a biological process. A detailed study of the influence of operating parameters of the electro-Fenton process on removal rates and biodegradability enhancement contributed not only to the general knowledge on the electro-Fenton process, but also to the advancement towards its upscaling and then further towards the industrial application of this technique

No processo UV/H2O2, oxidar o substrato a CO2 e água resulta em um elevado consumo de H2O2. Então, esse processo tem sido proposto como um pré-tratamento para reduzir a toxicidade a níveis seguros para o tratamento biológico posterior. Por essa razão, é necessário estudar o progresso da reação, pois a toxicidade de alguns intermediários formados durante a oxidação pode ser mais elevada que a do composto inicial. Neste trabalho, os experimentos foram realizados em um reator tubular fotoquímico, contendo em seu eixo uma lâmpada de vapor de mercúrio de baixa pressão, conectado a um tanque de recirculação. O processo UV/H 2O2 é aplicado no tratamento de água contendo fenol (50500mg C.L-1). Os resultados demonstraram que o principal produto da oxidação primária é o catecol, indicando que a hidroxilação ocorre predominantemente na posição orto. A abertura do anel aromático leva à formação de ácidos orgânicos, o que explica a diminuição do pH durante a reação. Foram identificados os seguintes ácidos: fórmico, oxálico, maleico e malônico. Na etapa seguinte desse trabalho, dois modelos cinéticos foram desenvolvidos. Os modelos foram baseados nas reações químicas e fotoquímicas iniciadas pelos radicais hidroxila gerados pela fotólise do peróxido de hidrogênio. Foram utilizados os valores encontrados na literatura para os parâmetros fotoquímicos e constantes cinéticas das reações fotoquímicas. Os resultados experimentais foram utilizados para estimar as constantes cinéticas das reações que envolvem os compostos aromáticos. No primeiro modelo foram contempladas todas as reações fotoquímicas envolvidas e, no segundo, apenas as consideradas mais significantes. Os resultados das simulações considerando os parâmetros ajustados mostraram uma melhor concordância com os dados experimentais para o primeiro modelo. As constantes cinéticas deste modelo para as reações nas quais o fenol é oxidado a catecol (k14) e hidroquinona (k15) foram 2,60x108L.mol-1.s-1 e 1,03x108L.mol-1.s-1, respectivamente. As constantes cinéticas para a oxidação do catecol (k17) e hidroquinona (k18) encontradas foram 1,41x108L.mol-1.s-1 e 2,02x108L.mol-1.s-1, respectivamente. Também foi observada elevada correlação entre as constantes k14 e k17 e entre k15 e k18.
In the UV/H2O2 process, the oxidation of the substrate to CO2 and water results in high H2O2 consumption. Due to this fact the process has been proposed as a pretreatment to reduce toxicity to safe levels prior to biological treatment. Thus, it is necessary to study the reaction progress because some intermediate compounds may be more toxic than the initial compound. In the present study experiments were carried out in a lab-scale tubular photochemical reactor with a low-pressure mercury vapor lamp placed in its axis, connected to a recirculation tank. The UV/H2O2 process was applied to the degradation of an aqueous solution containing phenol as a model pollutant (concentration range: 50-500mg.L-1). The experimental results indicated that orto-hydroxylation (catechol formation) was predominant. The cleavage of the aromatic ring resulted in the production of organic acids, which caused the pH decrease over the reaction time. The following acids were detected: formic, oxalic, maleic and malonic. The experimental results were used to estimate kinetic rate constants for the reactions involving aromatic compounds according to two kinetic models based on chemical and photochemical reactions, initiated by hydrogen peroxide photolysis to produce hydroxyl radical. Numerical values of chemical reaction rate constants and photochemical parameters were taken from literature. The first model considered all photochemical while the second model considered the most significant ones. The parameter fitting results showed better agreement with experimental values based on the first model. The resulting values for the rate constants according to this model were as follows: 2.60x108L.mol-1.s-1 for phenol oxidation to catechol, and 1.03x108L.mol-1.s-1 for phenol oxidation to hydroquinone by hydrogen peroxide. The reaction rate constants for the oxidation of catechol, and hydroquinone by hydrogen peroxide are 1.41x108L.mol-1.s-1 and 2.01x108L.mol-1.s-1, respectively. A high correlation was observed between constants k14 and k17, and between k15 and k18.

ABSTRACT As far back as the early 1900?s when it was discovered that water could be a mode of transmitting diseases, chlorine was used to disinfect water. In the 1970?s, the formation of disinfection by-products (DBPs) from the reaction of chlorine with natural organic matter was discovered. Since then there have been various studies on alternative disinfectants that could inactivate microorganisms and at the same time form less or no disinfection by-products. More recently the ultraviolet (UV) irradiation has been used to both disinfect and remove organic contaminants in drinking water. Though the use of UV irradiation has been found to be very effective in the inactivation of microorganisms, it does not provide a residual effect to maintain the water?s microbial quality in the distribution system. Due to this, a secondary disinfectant such as chlorine has to be used to achieve microbial stability, suggesting that the formation of chlorination disinfection by-products would still occur but perhaps in different quantities and with different chemical species. In this research, the use of factorial experiments and single factor experiments were used to determine the effects of pH, alkalinity and UV-fluence (dose) on the formation of three classes of disinfection by-products; haloacetic acids (HAAs), haloacetonitriles (HANs) and trihalomethanes (THMs). These disinfection by-products were measured in water samples following post-UV chlorination and the UV treatment was either UV photolysis or UV/H₂O₂. From the factorial experiment results, treatment of synthetic water with UV/H₂O₂, an advanced oxidation process (AOP), produced fewer post-UV chlorination disinfection by-products (PCDBPs) than UV photolysis. For chlorinated PCDBPs, the percentage difference between UV photolysis and UV/H₂O₂ was 55, 65 and 38% for total HAAs (HAA₉), total HANs (THANs) and total THMs (TTHMs) respectively. The percentage difference between UV photolysis and UV/H₂O₂ for brominated PCDBPs was 41 and 42% for HAA9 and TTHMs respectively. Both the use of pH and alkalinity proved to be factors that were significant in affecting the yields of the PCDBPs studied. Increases in alkalinity were found to increase the formation of PCDBPs in the treatment of synthetic water with UV/H₂O₂. Alkalinity had the opposite effect for PCDBP formed under UV photolysis conditions. Increases in pH always decreased the formation of PCDBPs. In the single factor experiments, haloacetic acid concentrations were unaffected as alkalinity was increased but dichloroacetonitrile and chloroform increased in concentration under treatment conditions of UV photolysis followed by chlorination. The UV/H₂O₂ treatment resulted in a decrease in concentration of the PCDBPs. In the pH studies, water samples were subjected only to the UV/H₂O₂ treatments and a reduction in concentration of PCDBPs occurred between pH 7 and 9.

The presence of trace organic compounds (TOrCs) in wastewater effluent and surface waters has raised attention due to their health and environmental effects. Some TOrCs are naturally attenuated via biodegradation, photo-degradation and/or adsorption, but some persist in the environment as contaminants in surface and ground waters. Thus, it is crucially important to understand their transformation pathways and their mechanisms following their discharge into the environment. This work presents research in three parts: • The first part represents an investigation of photo-transformation of TOrCs (e.g., furfuryl alcohol, p-cresol, gemfibrozil) under UV254, UVA and natural sunlight, and involving reactive oxygen species including singlet oxygen, hydroxyl radicals, triplet excited states, and specific inorganic radicals that are created by effluent organic matter (EfOM). Singlet oxygen was the only ROS, generated from effluent organic matter (EfOM) that mainly contributed to the photo-transformation of these selected TOrCs. A comprehensive mechanism and complementary kinetic model were proposed to predict the trajectories of TOrC removals via reaction with singlet oxygen. Simulations built on predicted quantum efficiencies accounted for light shading and competitive effects. Agreement between measurements and simulations was excellent. • The second part of the dissertation summarizes expected removal efficiencies for fifty-five TOrCs in alternative engineered and natural treatment processes including conventional biological treatment, advanced oxidation processes (AOP), reverse osmosis (RO), granular activated carbon (GAC), and sunlight photolysis. • The last section of the dissertation follows the trajectories of a series of TOrCs and total estrogenic activity in the Santa Cruz River, following their discharge from a wastewater treatment plant in the Tucson area. The study suggests that some TOrCs tend to persist in the environment while others experience photo (or other) transformations that diminish their concentrations or activities with distance and time of travel in the river. The attenuation of estrogenic activity was dependent on sunlight and the presence of specific (unidentified) wastewater components.

Orientador: José Roberto Guimarães
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A ofloxacina é um antimicrobiano de amplo espectro frequentemente encontrado em concentrações significativas em efluentes e águas superficiais. A contínua introdução deste fármaco no meio ambiente constitui um risco potencial em longo prazo para os organismos não alvos ou para a saúde humana. Neste estudo foi avaliada a degradação da ofloxacina pelos processos oxidativos avançados (POA) peroxidação assistida por radiação ultravioleta (UV/H2O2) e fotocatálise (UV/TiO2 e UV/TiO2/H2O2). Foi avaliada também a atividade antimicrobiana residual do fármaco, utilizando a bactéria E. coli, e a toxicidade aguda (Vibrio fischeri). A concentração de ofloxacina foi monitorada utilizando-se cromatografia líquida de alta eficiência (CLAE). Os resultados obtidos indicam que os POA aplicados foram eficientes para a degradação desse fármaco. O processo UV/H2O2 alcançou degradação de 99%, após 60 min de reação. Para o processo UV/TiO2, a eficiência de degradação obtida foi de 89,3% após 60 min e a adição de peróxido de hidrogênio elevou a eficiência para 97,8%. A atividade antimicrobiana do fármaco foi reduzida consideravelmente, alcançando 95% de remoção com a aplicação do UV/H2O2 e 96% utilizando o processo UV/TiO2/H2O2. A toxicidade das amostras não aumentou no decorrer da aplicação destes POA, indicando a potencial utilização destes processos para o tratamento de soluções aquosas contendo ofloxacina
Abstract: Ofloxacin is a broad-spectrum antimicrobial agent which is frequently found in significant concentrations in wastewater and surface water. Its continuous introduction into the environment constitutes a potential risk to non-target organisms or to human health. This study evaluated ofloxacin degradation by the UV/H2O2, UV/TiO2 and UV/TiO2/H2O2 advanced oxidation process (AOPs), residual antimicrobial activity (E. coli), and acute toxicity (Vibrio fischeri). Ofloxacin concentration was monitored with HPLC analyses. The results obtained shown that AOPs applied were efficient for ofloxacin degradation. For UV/H2O2, degradation efficiency was 99% in 60 min of reaction. For UV/TiO2, degradation efficiency was 89.3% in 60 min of reaction when applied 128 mg L-1 TiO2. The addition of 1.68 mmol L-1 of hydrogen peroxide increased the degradation to 97.8%. For both processes, the antimicrobial activity was considerably reduced throughout the reaction, reaching 95% removal when UV/H2O2 was applied and 96% using the UV/TiO2/H2O2 process. The toxicity of the samples did not increase during AOP application, indicating the potential use of these processes for the treatment of aqueous solutions containing ofloxacin
Mestrado
Saneamento e Ambiente
Mestra em Engenharia Civil

Nos últimos anos, os processos oxidativos avançados (POAs) têm emergido como métodos potencialmente poderosos para transformar poluentes orgânicos recalcitrantes em substâncias menos tóxicas. O presente trabalho visa estudar a degradação de clorofenóis 2,4-diclorofenol (2,4-DCF) e pentaclorofenol (PCF) em solução aquosa por meio do processo foto-Fenton. Os experimentos foram realizados em um reator fotoquímico, em regime batelada, com recirculação e admissão contínua de peróxido de hidrogênio. Os efeitos das concentrações iniciais de clorofenóis, H2O2 e Fe(II), bem como, da potência da lâmpada de vapor de mercúrio, foram estudados a partir de um planejamento experimental Doehlert em multiplos níveis e analisados segundo a metodologia de superfícies de respostas. A foto-oxidação foi monitorada por medidas da concentração de carbono orgânico total (TOC) e do espectro de absorção da solução ao longo do tempo e, em alguns casos, medidas de toxicidade por meio de bioensaios com Artemia sp. Os resultados dos experimentos realizados com 2,4-DCF evidenciaram degradação gradativa, com remoções de TOC superiores a 99%, após 1 hora de tratamento, além de remoção de toxicidade, mesmo para altas concentrações iniciais do poluente (até ca. 415 mgC L-1). Nos experimentos realizados com PCF observouse decaimento inicial de TOC bastante rápido (15 minutos), o que sugere que a degradação dos clorofenóis torna-se mais rápida com o aumento do número de átomos de cloro ligados ao anel aromático. Foi removida mais da metade do TOC inicial por volta de 30 minutos de reação, obtendo-se remoções de até 90,8% ao final do tratamento. Por outro lado, comparado ao 2,4-DCF, no caso do PCF observou-se redução acentuada da taxa de remoção de TOC após esse tempo, o que pode ser explicado a partir da maior concentração de íons cloreto em solução, da formação de complexo estável desses íons com Fe(III) e de espécies geradas a partir de reações envolvendo esse complexo. No conjunto, os resultados comprovam a viabilidade do processo foto-Fenton para remediação de efluentes aquosos contendo clorofenóis.
In recent years, advanced oxidation processes (AOP) have emerged as potentially powerful methods to transforming organic pollutants into harmless substances. The present work aims to study the degradation of chlorophenols (2,4-dichlorophenol and pentachlorophenol) in aqueous solution by the photo-Fenton process. The experiments were conducted in a batch recycle photochemical reactor with continuous feed of hydrogen peroxide solution. The effects of the initial concentrations of chlorophenols, H2O2, and Fe(II), as well as of the electric power of mercury vapor lamp, were studied by means of a Doehlert multivariate experimental design at multiple levels. Experimental results were analyzed according to the response surface methodology. In order to characterize the degradation of the pollutant, time-measurements of the total organic carbon concentration (TOC) as well as the absorbance spectra of the solution, were carried out. In some cases toxicity bioassays were carried out with Artemia sp. The results obtained from experiments with 2,4-dichlorophenol showed a gradual degradation, with more than 99% of TOC removals after 1 hour of treatment, along with toxicity removal, even for high initial pollutant concentrations (ca. 415 mgC L-1). In the case of pentachlorophenol, a fast initial TOC decrease (around 15 minutes) was observed, suggesting that chlorophenols degradation becomes faster with the increment of chloro atoms number bounded to the aromatic ring. More than a half of the initial TOC was removed around 30 minutes of reaction, rising 90.8% of TOC removal at the end of the treatment. In the other hand, comparing to 2,4-DCF, for PCF a marked reduction of the maximum rate of TOC removal after that time. This can be explained by higher concentrations of chloride ions in the solution, for the formation of stable complexes with Fe(III) ion and resulting species in reaction involving such complexes. As a whole, the results confirm the effectiveness of the photo-Fenton process for the remediation of aqueous solutions containing chlorophenols.

The thesis deals with removal of organosilicon compounds in the energy recovery of biogas. Alternative adsorbents for the siloxane removal were studied, and the physical and chemical mechanisms involved in the siloxane adsorption were discovered, which improved the yield of the adsorption and regeneration technologies using both activated carbons and zeolites. Moreover, several technologies based on advanced oxidation processes have been applied in order to regenerate and reuse the exhausted adsorbents. The thesis studies the siloxane removal at lab-scale close to real scenario conditions, including the competitive adsorption with compounds usually found in biogas, in the presence of humidity and with the same gas matrix, which allowed to select the most efficient materials for this purpose. Therefore, the knowledge reported in the thesis dissertation is directly transferable to field application to upgrade the siloxane removal system
Aquesta tesi estudia l'eliminació de compostos volàtis de silici (siloxans) per la recuperació energètica del biogàs. Es van estudiar diferents adsorbents per l'adsorció de siloxans, determinants les propietats físico-químiques superficials que en condicionen l'eficiència, permetent millorar el rendiment de l'adsorció i permetent la regeneració en carbons actius i zeolites esgotats. La tesi estudia l'eliminació de siloxans a escala de laboratori en condicions properes a les reals del biogàs, incloent l'adosrció competitiva amb altres compostos orgànics volàtics, en presència d'humitat i amb diferents matrius gasoses, la qual cosa va permetre seleccionar els materials òptims per aquest propòsit.Per tant el coneixement derivat d'aquesta tesi és directament transferible per tal de millorar els sistemes d'eliminació siloxanes

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
UNISINOS - Universidade do Vale do Rio dos Sinos
O lixiviado de aterro sanitário tem se caracterizado pela alta concentração de matéria orgânica recalcitrante, nitrogênio amoniacal e compostos tóxicos. Compostos orgânicos recalcitrantes são raramente removidos por processos tradicionais de tratamentos de efluentes, o que dificulta o atendimento aos padrões de lançamento de efluentes. Da mesma forma, o descarte do esgoto doméstico gerado pelas comunidades precisa também de tratamentos prévios para não impactar o meio ambiente. Devido às características do esgoto doméstico, com baixas concentrações de matéria orgânica carbonácea e cor em relação ao lixiviado, vem permitindo que o tratamento combinado desses efluentes seja uma alternativa viável. Diante desse quadro, este trabalho visou à avaliação do tratamento combinado de esgoto doméstico da estação de tratamento de efluentes (ETE) da Unisinos e lixiviado bruto do aterro sanitário de São Leopoldo, utilizando ozônio (O3) como agente oxidante. Os efluentes foram tratados na unidade experimental composta por um reservatório com capacidade de até 500L e um reator cilíndrico de PVC com 250 mm de diâmetro e 2,20 m de altura, operando com fluxo ascencional, totalizando um volume de trabalho de 108 L e preenchido em 2/3 do seu volume total com Anel Pall de 1,5”. Realizaram-se três ensaios em bateladas, com duração de cinco horas e três ensaios com duração de duas horas, com diferentes produções de O3 de 8,9; 9,6 e 10,5 g de O3.h-1, aplicados à mistura de 2% de lixiviado de aterro sanitário (LAS) ao esgoto doméstico (2 L de LAS e 158 L de esgoto). Cada ensaio foi realizado em duplicata, sendo monitorados os seguintes parâmetros: Demanda Química de Oxigênio, Demanda Bioquímica de Oxigênio, Cor Aparente e Verdadeira, Turbidez, pH e calculada as taxas de utilização e de perda de O3. Os resultados evidenciaram que o tratamento por O3 pode ser uma alternativa de pré-tratamento de efluentes, obtendo remoções médias de DQO, DBO, CA, CV e Turbidez de até 46%, 51%, 86%, 86% e 81% respectivamente em cinco horas de ensaio e remoções médias de até 23%, 48%, 78%, 76% e 58% respectivamente em duas horas de ensaio. As maiores taxas de remoções foram alcançadas nos ensaios com maiores vazões de O2 e produções de O3 e nas duas primeiras horas de ensaio. Só foi possível o atendimento aos padrões de lançamentos de efluentes exigidos pela legislação vigente, nos ensaios com duração de cinco horas e com a maior produção de O3 e vazão de O2. O sistema de tratamento também contribuiu para uma melhora na biodegradabilidade do efluente se analisada a relação DBO/DQO e cor. Quanto as taxas de utilização e de perda de O3, verificou-se que a maior quantidade consumida de O3, ocorreu para os parâmetros indicativos de matéria orgânica e para os ensaios com a menor produção de O3.
Landfill leachate has been characterized by the high concentration of recalcitrant organic matter, ammoniacal nitrogen and toxic compounds. Recalcitrant organic compounds are rarely removed by traditional effluent treatment processes. In addition, the treatment of the leachate is colloquial to meet the discharge standards of the effluent. Likewise, the domestic sewage disposal generated by the communities also needs previous treatments to avoid impacts on the environment. Due to the characteristics of domestic sewage, with low concentrations of organic carbon in relation to the leachate, it has allowed the combined treatment of these effluents to be a viable alternative. In view of this situation, this work had the objective of evaluating the combined treatment of domestic sewage of (ETP) and the raw leachate of the San Leopoldo landfill using ozone (O3) as an oxidizing agent. Three batch trials were carried out with a scheduled duration of five hours and three trials lasting two hours, with different yields of O3 of 8.9, 9.6 and 10.5 g of O3.h-1, applied to the mixture Of 2% of landfill leachate) For domestic sewage (2L of LAS and 158L of sewage). Each assay was performed in duplicate and the following parameters were monitored: Oxygen Chemical Demand, Biochemical Oxygen Demand, Apparent and True Color, Turbidity, pH and calculated O3 utilization and loss rates. The results showed that the treatment with O3 can be an excellent alternative of pretreatment of effluents, obtaining average removals of COD, BOD, CA, CV and Turbidity of up to 46%, 51%, 86%, 86% and 81 % Respectively. Average test and removal hours of up to 23%, 48%, 78%, 76% and 58%, respectively, in two hours of testing. The highest removal rates were obtained in the tests with higher flows of O2 and yields of O3 and in the first two hours of the test. It was only possible to meet the effluent release standards required by current legislation, in trials with a duration of five hours and with the highest production of O3 and O2. The treatment system also contributed to an improvement in the biodegradability of the effluent if the BOD/COD ratio was analyzed. As for the rates of use and loss of O3, it was verified that the highest amount of O3 occurred for the parameters indicative of organic matter and for the tests with lower production of O3. The higher the O3 production, the higher the O3 loss and the greater oxidant loss may have been due to volatilization in the effluent accumulation reservoir, since there was no gas loss due to Off-gas and the method used Not Detected The residual ozone.

Estudou-se a degradação dos fármacos acetaminofeno (ACT), atenolol (ATL), bezafibrato (BZF), diclofenaco (DIC) e ibuprofeno (IBU) em solução aquosa através de fotólise e peroxidação fotoassistida. As soluções foram caracterizadas antes e após os processos de fotólise e UV/H₂O₂ quanto à degradação dos fármacos e à remoção de carbono orgânico total. Também foi avaliada a degradação por fotólise dos fármacos em uma matriz real (efluente de estação de tratamento de esgoto, ETE). Os experimentos foram realizados em um reator anular com lâmpada de vapor de mercúrio de baixa pressão de 36 ou 75 W e concentrações iniciais de 5 ou 20 mg L⁻¹ de cada fármaco, em mistura e individualmente, no caso dos estudos de fotólise UV. Os resultados mostraram absorção de radiação UV (254 nm) pelo ACT superior à dos demais fármacos (€=8990 L mol⁻¹ cm⁻¹), e comparativamente inferior para o ATL e IBU (€=725 e 1080 L mol⁻¹ cm⁻¹, respectivamente). Não houve degradação por hidrólise após 24h em qualquer pH. O DIC e o BZF degradaram-se mais rapidamente, independentemente do processo fotoassistido. As concentrações de DIC nos experimentos realizados com [DIC]0=5 mg L⁻¹ ficaram abaixo do limite de detecção após 20 minutos de irradiação. Na presença de H H₂O₂ as concentrações dos contaminantes ficaram abaixo do limite de detecção após 50 minutes para concentrações iniciais de 20 mg L⁻¹. Os resultados dos ensaios de toxicidade nos experimentos realizados com a mistura de fármacos mostraram valores de CE50 inferiores aos valores obtidos nos experimentos com a solução dos fármacos individuais. Os valores de TOC apresentaram redução de até 13% ao final de 120 minutos, o que comprova a persistência dos produtos de degradação. A degradação por fotólise UV do ATL e do ACT ocorreu mesmo em efluente de ETE, sendo a eficiência desse processo semelhante à obtida usando-se água como matriz. Esses resultados são úteis para compreensão da remediação de águas e efluentes contendo esses contaminantes emergentes por meio de processos foto-oxidativos.
This work aimed at studying the degradation of the following pharmaceutical compounds in aqueous solution by means of photolysis and photoassisted peroxidation: acetaminophen (ACT), atenolol (ATL), bezafibrate (BZF), diclofenac (DIC), and ibuprofen (IBU). Solutions were characterized before and after photolysis and UV/H2O2 processes regarding drug degradation and total organic carbon removal. In addition, the photolysis of the pharmaceutical compounds was investigated in a real wastewater matrix (effluent from a sewage treatment plant, STP). The experiments were carried out in an annular photochemical reactor equipped with a low pressure mercury lamp (36 or 75 W) and initial solution concentrations of 5 and 20 mg L-1 of each drug, for the mixture and individual compounds, in the case of UV photolysis studies. The results revealed higher absorption of UV radiation (254 nm) by ACT than that shown by the other pharmaceutical compounds (=8990 L mol-1 cm-1), and comparatively lower for ATL and IBU (=725 and 1080 L mol-1 cm-1, respectively). No hydrolysis was observed after 24 hours at any pH. The degradation of DIC and BZF was faster, regardless the photoassisted process. DIC concentrations in the experiments carried out with [DIC]0=5 mg L-1 were below the detection limit after 20 minutes of irradiation. In the presence of H2O2, contaminant concentrations were below the detection limit after 50 minutes of irradiation for initial concentrations of 20 mg L-1. The results of the toxicity assays for the experiments carried out with the mixture of pharmaceutical compounds showed CE50 values lower than those obtained with the compounds individually. TOC removals up to 13% after 120 minutes were obtained, therefore confirming the formation of persistent degradation products. In the case of ATL and ACT, UV degradation occurred even in STP wastewater and the efficiency of the process was similar to that obtained with pure water. The results obtained in this study are useful to understand the treatment of water and wastewater contaminated with this class of emerging pollutants by means of photo-oxidative process.

Orientador: José Roberto Guimarães
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: Nesse trabalho foi avaliada a degradação de flumequina (500 ?g L-1) por processo físico (fotólise-UV254), químico (peroxidação-H2O2) e oxidativos avançados (fotoperoxidação-UV/H2O2, fotocatálise heterogênea-UV/TiO2, reagente de Fenton-Fe(II)/H2O2, foto-Fenton-UV/Fe(II)/H2O2, eletroquímico e foto-eletroquímico) em um reator fotoquímico de recirculação em batelada. Os processos UV/H2O2 (CH2O2 inicial = 1,0 mmol L-1) e a fotocatálise (CTiO2 suspensão = 0,62 mmol L-1) foram os processos mais eficientes, reduzindo cerca de 85% da flumequina em 15 min de reação. A fotólise provocou a degradação da flumequina em 91,2% em 60 min de ensaio, enquanto que o processo foto-Fenton 94%, quando usados 10,0 e 0,25 mmol L-1 de H2O2 e Fe(II), respectivamente. Por outro lado, a peroxidação (CH2O2 = 1,0 mmol L-1) e o reagente de Fenton (CFe(II) = 2,0 mmol L-1 e CH2O2 = 0,5 mmol L-1) não atingiram mais de 10% e 40 % de degradação, respectivamente, após 60 min de reação. Os processos eletroquímico e foto-químico atingiram aproximadamente 82 e 85% de degradação da flumequina, após 60 min de reação quando aplicado 45 mA cm-2. A diminuição da atividade antimicrobiana das soluções submetidas aos processos oxidativos avançados foi proporcional à concentração residual da flumequina na solução. Não foi observada atividade antimicrobiana residual nas soluções submetidas aos seguintes processos oxidativos avançados e condições: UV/ H2O2 (CH2O2 = 1,0 mmol L-1, 30 min de reação), UV/TiO2 (CTiO2 = 0,62 mmol L-1, 30 min de reação), foto-Fenton (CFe(II) = 0,25 mmol L-1 e CH2O2 = 10 mmol L-1, 60 min de reação) e foto-eletroquímico (45 mA cm-2 e 60 min de reação). Os intermediários formados foram monitorados em 10, 15 e 30 min de reação nos processos oxidativos avançados e fotólise, e foi observado que os intermediários propostos possuíam uma atividade antimicrobiana menor que a flumequina. A eficiência dos processos UV/ H2O2 e UV/TiO2 (1,0 mmol L-1 e 0,62 mmol L-1 de H2O2 e TiO2) foi próximo a 100%, removendo totalmente a atividade antimicrobiana da solução
Abstract: This work evaluated the degradation of flumequine (500 ?g L-1) by physical process (photolysis-UV254), chemical process (H2O2 - peroxidation) and advanced oxidation processes (photoperoxidation - UV/H2O2, heterogeneous photocatalysis - UV/TiO2, Fenton's reagent - Fe(II)/H2O2, photo-Fenton - UV/Fe(II)/H2O2) in a batch-recirculation photochemical reactor. The processes UV/H2O2 (CH2O2 = 1.0 mmol L-1) and photocatalysis (CTiO2 suspension = 0.62 mmol L-1) are the most efficient ones, reducing about 85% of the flumequine in 15 min of reaction time. The photolysis caused 91.2% of flumequine degradation after 60 min of assay, while the photo-Fenton process degraded 94% of the drug when used 10.0 and 0.25 mmol L-1 of H2O2 and Fe(II), respectively. Moreover, peroxidation (CH2O2 = 1,0 mmol L-1) and Fenton's reagent (CFe(II) = 2.0 mmol L-1 and CH2O2 = 0.5 mmol L-1) did not achieve more than 10% and 40% degradation, respectively, after 60 min of reaction. Eletrochemical and photo-eletrochemical processes degraded about 82% and 85%, respectively, after 60 min of reaction at 45 mA cm-2. The decrease of the solutions antimicrobial activity subjected to advanced oxidation processes was proportional to the residual concentration of flumequine in the solution. There was no residual antimicrobial activity in the solutions subjected to the following advanced oxidation processes and conditions: UV/H2O2 (CH2O2 = 1.0 mmol L-1, 30 min of reaction), UV/TiO2 (CTiO2 = 0.62 mmol L-1, 30 min of reaction), photo-Fenton (CFe(II) = 0.25 mmol L-1 and CH2O2 = 10 mmol L-1, 60 min of reaction) and photo-eletrochemical (45 mA cm-2, 60 min of reaction). The intermediates formed were monitored at 10, 15 and 30 min of reaction in photolysis and advanced oxidation processes, where it was observed that the proposed byproducts owned a lower antimicrobial activity than flumequine. The efficiency of the processes UV/H2O2 and UV/TiO2 (1.0 mmol L-1 and 0.62 mmol L-1 of H2O2 and TiO2, respectively) was close to 100%, entirely removing the antimicrobial activity of the solution
Doutorado
Saneamento e Ambiente
Doutor em Engenharia Civil

O processo de adsorção por carvão ativado é uma técnica muito aplicada para tratamento de efluentes. Porém o tratamento que envolve adsorção não é um sistema completo, pois há a necessidade da destruição dos compostos que foram imobilizados na superfície do carvão. Frente a esse problema, métodos alternativos de regeneração de carvão ativado são investigados. Os processos Fenton e foto-Fenton são considerados tecnologias promissoras de tratamento de efluentes, e foram testados para regenerar o carvão ativado. Este trabalho objetiva estudar a adsorção de fenol em carvões ativados (CAs) e a consecutiva regeneração in-situ do carvão pela oxidação de (foto-) Fenton. Duas operações diferentes foram realizadas: 1) sistema de batelada, a fim de investigar a influência das concentrações de Fe2+ e H2O2; 2) adsorção contínua em leito fixo, seguido de circulação em batelada dos reagentes de Fenton pelo leito de CA saturado, para examinar a eficiência do processo real. Foram estudados dois tipos de carvão ativado: CA L27 (meso e microporoso) e CA S23 (somente microporoso). No reator de batelada as melhores condições encontradas para a mineralização do poluente no sistema Fenton homogêneo não são as melhores para a regeneração do CA: foi observada uma redução contínua da capacidade de adsorção do L27 após 3 oxidações, devido à redução tanto da massa do CA quanto da área superficial. Uma maior concentração de Fe2+ e menor concentração de H2O2 (2 vezes a estequiometria) levou a uma recuperação de 50% da capacidade de adsorção inicial em pelo menos 4 ciclos consecutivos para o L27, enquanto que cerca de 20% para o S23. No processo consecutivo de adsorção contínua/oxidação de Fenton em batelada, a eficiência de regeneração atinge de 30% a 40% para o L27 após dois ciclos independente da concentração da alimentação e menos de 10% para o S23. O processo foto-Fenton realizado para o L27 levou à quase completa mineralização e aumentou a recuperação da capacidade de adsorção do CA (56% após dois ciclos).
The adsorption process by active carbon is a technique applied extensively for wastewater treatment. However the tertiary treatment involving adsorption is not a complete system, since there is a need of destruction of the compounds that were immobilized on the carbon surface. In face of this problem, some alternative regeneration methods of active carbon are investigated. Fenton and photo-Fenton processes have been considered promising technologies for wastewater treatment and have been tested to regenerate the AC. The purposes of this study are the adsorption of phenol on activated carbons (ACs) and the consecutive in-situ regeneration of carbon by (photo-) Fenton oxidation. Two different operations have been carried out: 1) batch procedure in order to investigate the influence of Fe2+ and H2O2 concentrations; 2) continuous fixed bed adsorption, followed by a batch circulation of the Fentons reagent through the saturated AC bed, to examine the efficiency of the real process. Two different activated carbons have been also studied: a both micro- and mesoporous AC (L27) and an only microporous one (S23). In the batch reactor the best conditions found for pollutant mineralization in the homogeneous Fenton system are not the best for AC regeneration: a continuous reduction of adsorption capacity of L27 is observed after 3 oxidations, due to the decrease of both AC weight and surface area. Higher concentration of Fe2+ and lower concentration of H2O2 (2 times the stoechiometry) lead to a 50% recovery of the initial adsorption capacity during at least 4 consecutive cycles for L27, while about 20% for S23. In the consecutive continuous adsorption/batch Fenton oxidation process, the regeneration efficiency reaches 30% to 40% for L27 after two cycles whatever the feed concentration and less than 10% for S23. A photo- Fenton test performed on L27 shows almost complete mineralization (contrary to dark Fenton) and further improves recovery of AC adsorption capacity although not complete (56% after two cycles).

Bisphenol A (BPA) is widely used in the production of plastics, epoxy resins and polycarbonates. It is a toxic, endocrine disruptor compound. Different studies have shown the presence of BPA in several environmental systems, classifying it as a worldwide persistent pollutant which may act synergistically with other pollutants. In this context, advanced oxidation processes (AOP) have received great attention due to their ability to degrade pollutants with such characteristics, through their transformation into less hazardous compounds or even their mineralization. Although there are investigations on the use of AOPs for BPA degradation, systematic studies on the effects of process variables, coupled with the statistical interpretation of the results are virtually non-existent. Furthermore, to the best of our knowledge, a rigorous kinetic model has not yet been proposed for the degradation of this pollutant by the H2O2/UV process. The objective of this work was to evaluate BPA degradation by the H2O2/UV process, investigating the effects of the initial H2O2 concentration and the specific rate of photons emission (EP,0) by means of a Doehlert experimental design, combined with the response surface methodology. The experiments were performed in a photochemical tubular reactor equipped with a 254-nm UV lamp, for [H2O2]0 and EP,0 in the ranges 1.6-9.6 mmol L-1 and 0.87 × 1018-3.6 × 1018 photons L-1 s-1, respectively. Total BPA degradation was achieved after 60 min of irradiation in all experiments. The best conditions were [H2O2]0 = 7.6 mmol L-1 and EP,0 = 3.6 × 1018 photons L-1 s-1, for which the best performance was obtained regarding the BPA degradation rate, BPA degradation after 15 min, and the second highest TOC removal after 180 min. However, in most experiments less than 75% TOC removal was observed, with 95% mineralization obtained only for the superior [H2O2]0 and EP,0. A mathematical model was developed, considering the reactor characteristics and the radiation field, based on the line source with parallel emission (LSPP) approach, in combination with the radiative transfer equation (RTE), mass balances, and a detailed kinetic model of the H2O2/UV process. The steady-state approximation was applied for all radical species. In the estimation of unknown kinetic constants, the non-linear least squares method was employed. The model was able to satisfactorily fit experimental BPA and H2O2 concentrations as a function of time. This work shows that the H2O2/UV process is a good alternative for BPA removal from aqueous streams, with total degradation of the target compound and adequate percent mineralization under optimal operating conditions. Such conditions may serve as first guidelines for pilot-plant and industrial processes operation. In addition, simulations using the proposed kinetic model may provide useful information for the design and scale-up of pre- or post-treatment of effluents containing this pollutant.
O bisfenol A (BPA) é amplamente utilizado na fabricação de plásticos, resinas epóxi e policarbonatos. Trata-se de um composto tóxico e um desregulador endócrino. Diferentes estudos evidenciam a presença do BPA em diversos compartimentos ambientais em todo planeta, identificando-o como um poluente persistente e resistente à degradação biológica, que apresenta efeitos sinergéticos com outros poluentes. Nesse contexto, os processos oxidativos avançados (POA) têm recebido atenção devido a sua capacidade em degradar poluentes com tais características, transformando-os em compostos menos perigosos ou até mesmo mineralizando-os totalmente. Apesar de haver trabalhos na literatura acerca da utilização de POA para degradação de BPA, estudos sistemáticos dos efeitos de variáveis de processo junto com a interpretação estatística dos resultados são virtualmente inexistentes. Além disso, até onde se sabe um modelo cinético rigoroso ainda não foi proposto para a degradação desse poluente por meio do processo H2O2/UV. Este trabalho teve por objetivo avaliar a degradação do BPA pelo processo H2O2/UV, investigando os efeitos da concentração inicial de H2O2 e da taxa específica de emissão de fótons (EP,0) por meio de um projeto experimental Doehlert, combinado com a análise de superfície de resposta. Os experimentos foram realizados em um reator tubular fotoquímico equipado com uma lâmpada UV de 254 nm, para [H2O2]0 e EP,0 entre 1,6-9,6 mmol L-1 e 0,87 × 1018 - 3,6 × 1018 fótons L-1 s-1, respectivamente. Todos os experimentos sob H2O2/UV resultaram em total degradação do BPA após 60 min de irradiação. Nesse caso, as melhores condições foram [H2O2]0 = 7,6 mmol L-1 e EP,0 = 3,6 × 1018 fótons L-1 s-1, para as quais se obteve o melhor desempenho quanto à taxa de degradação de BPA e à remoção após 15 min, e a segunda maior remoção de COT após 180 min. Entretanto, na maioria dos experimentos menos de 75% de remoção de COT foram observados, com 95% de mineralização obtida apenas para os maiores [H2O2]0 e EP,0. Elaborou-se um modelo matemático que considera as características do reator utilizado e o campo de radiação, baseado no modelo de fonte linear de emissão em planos paralelos (LSPP), combinado à equação de transferência radiativa (RTE), aos balanços materiais e a um modelo cinético detalhado do processo H2O2/UV. Foi empregada a aproximação de estado estacionário para todas as espécies radicalares. Na estimativa das constantes cinéticas desconhecidas, utilizou-se o método de mínimos quadrados não linear. Esse modelo foi capaz de ajustar satisfatoriamente as concentrações experimentais de BPA e de H2O2 em função do tempo. Este trabalho mostra que o processo H2O2/UV constitui uma alternativa conveniente para a degradação de BPA em matrizes aquosas, com total degradação do composto alvo e porcentagem de mineralização adequada nas condições ótimas de operação. Tais condições podem servir como diretrizes iniciais de processamento em escalas piloto e industrial. Por sua vez, simulações empregando o modelo matemático proposto permitem gerar informações úteis para projeto e aumento de escala de processos de pré- ou pós-tratamento de efluentes contendo esse poluente.

This PhD thesis investigated solid and liquid waste treatment systems for Sureclean, a waste Management company based in the North of Scotland. Sureclean receives a diverse range of waste streams and the increasing need for sustainable development as well as stringent environmental legislation motivated this research to develop an integrated waste treatment system. Waste characterisation was conducted using a range of analytical instrumentation to identify the TPH, COD, heavy metals content, TOC, and particle size of Sureclean waste streams. From there, four treatment systems were investigated utilising Sureclean waste streams: mechanical separation, chemical treatment, electro-coagulation and the advanced oxidation process. Laboratory and field trials were conducted using these different treatment techniques and the analysis was performed to verify the treatment results. The result of these trials led to the development of four modular waste treatment units, that form the outcome of this research: the Sureclean Water Treatment System (SWTS), a filtration based mechanical separation system was shown to reduce the TSS, BOD and TOC content of an oily wastewater; the Sureclean Sludge Separation System (SSSTS), a chemical-enhanced filtration based system was demonstrated to reduce 52.6 % of the sewage sludge volume; the Sureclean Electro-coagulation Water Treatment System (SEWTS), a system that agglomerates colloid particles and demulsifies oil removed 99.9 % of TPH from Sureclean interceptor effluent; and the Sureclean Advanced Water Treatment System (SAWTS), an advanced oxidation process which was demonstrated to reduce the TPH of a contaminated groundwater collected from an ex-gas work. The treated effluent could be discharged to Sureclean interceptor. The four treatment units developed in this research expanded Sureclean waste treatment capabilities and an integrated system was developed to treat different waste streams and to improve the treatment efficiency thus increasing the revenue and future waste stream options for Sureclean.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico
O descarte de efluentes tÃxteis em Ãguas superficiais representa um sÃrio problema ambiental e de saÃde pÃblica devido, principalmente, à presenÃa de corantes na sua composiÃÃo, muitos dos quais sÃo potencialmente tÃxicos e carcinogÃnicos. A remoÃÃo de cor e a mineralizaÃÃo de seus subprodutos à uma das maiores dificuldades enfrentadas pelas estaÃÃes de tratamento de efluentes das indÃstrias desse segmento. Nesta pesquisa, buscou-se avaliar o tratamento de efluentes tÃxteis em sistemas anaerÃbios de um e dois estÃgios, estudar opÃÃes de pÃs-tratamento por processos biolÃgicos aerÃbios e de oxidaÃÃo avanÃada, e utilizar testes de ecotoxicidade no estudo dos diversos efluentes produzidos. Foram realizados experimentos com sistemas anaerÃbios de um (R1) e dois estÃgios (R2) tratando esgotos tÃxteis real e sintÃticos. Nestes experimentos, foram avaliados o efeito da concentraÃÃo do corante, concentraÃÃo do doador de elÃtrons externo, o tempo de detenÃÃo hidrÃulica (TDH) e o efeito do mediador redox antraquinona-2,6-dissulfonato (AQDS) na eficiÃncia de descoloraÃÃo. Outros dois sistemas anaerÃbios de um estÃgio (R3 e R4) foram operados em paralelo, alimentados com esgoto tÃxtil real com TDH de 12h a fim de avaliar o efeito do AQDS na descoloraÃÃo de efluentes reais. Durante o pÃs-tratamento aerÃbio, foi avaliada a aplicaÃÃo de um reator de lodos ativados em batelada seqÃencial com ciclo total de 24h, operando com os efluentes, sintÃtico e real, previamente tratados no reator UASB. Avaliou-se, tambÃm, a aplicaÃÃo do processo de oxidaÃÃo avanÃada (POA) do tipo UV/H2O2 como opÃÃo de pÃs-tratamento dos efluentes tÃxteis tratados no reator UASB, tanto em relaÃÃo à descoloraÃÃo quanto na mineralizaÃÃo dos subprodutos gerados na reduÃÃo dos corantes. A avaliaÃÃo da toxicidade dos efluentes foi realizada pelos ensaios de toxicidade aguda utilizando a Daphnia magna como organismo teste. Os resultados dessa pesquisa revelaram que o sistema anaerÃbio de dois estÃgios mostrou-se mais estÃvel que o sistema de um estÃgio quando operado como o esgoto real e sintÃtico com os corantes Congo Red (CR) e Reactive Black 5 (RB5) e mais eficiente para o corante RR2 na ausÃncia de AQDS. Entretanto, na presenÃa do AQDS a eficiÃncia de descoloraÃÃo do Reactive Red 2 (RR2) foi elevada para os dois sistemas, mascarando o efeito da separaÃÃo de fase. Para o efluente tÃxtil real, nÃo foi verificado efeito algum da aplicaÃÃo do AQDS no R3, mesmo em baixo TDH e limitada concentraÃÃo de doador de elÃtrons. O pÃs-tratamento dos efluentes real e sintÃticos no reator aerÃbio foi capaz de reduzir a DQO abaixo de valor exigido pela portaria 154/02 da SEMACE. O processo de oxidaÃÃo avanÃada com UV/ H2O2 mostrou-se eficaz na remoÃÃo de cor e DQO dos efluentes tÃxtil real e sintÃticos. Os testes de toxicidade aguda ratificaram o potencial tÃxico dos efluentes tÃxteis e os subprodutos de sua degradaÃÃo assim como a capacidade de mineralizaÃÃo das aminas em sistemas seqÃenciais anaerÃbio/aerÃbio.
Disposal of textile effluents in surface waters represents a serious environmental and public health problem mainly due to the presence of dyes in their composition, many of which are potentially toxic and carcinogenic. The color removal and mineralization of byproducts is the major difficulty faced by the wastewater treatment plants of these industries. This thesis studied the treatment of textile effluents in one-stage and two-stage anaerobic systems, post-treatment options by using aerobic biological and advanced oxidation processes, and use the ecotoxicity tests for the various effluents produced. Experiments were performed in one-stage (R1) and two-stage (R2) anaerobic systems treating real and synthetic textile wastewaters. In these experiments, we evaluated the dye concentration effect, as well as external electron donor concentration, hydraulic retention time (HRT) and the redox mediator anthraquinone-2,6-disulfonate (AQDS) effect on color removal efficiency. Two other one-stage anaerobic systems (R3 and R4) were operated in parallel at the HRT of 12 hours and fed with real textile wastewater to assess the AQDS effect on the decolourisation of real textile effluents. During the aerobic post-treatment, we evaluated the application of sequencing batch reactor (SBR) with 24 hours total cycle to treat synthetic and real textile wastewaters pre-treated in the UASB reactor. We also evaluated the application of UV/H2O2 advanced oxidation process (AOP) to treat real textile wastewaters pre-treated in the UASB reactor, both in terms of color removal and mineralization of byproducts generated upon dye reduction. The evaluation of the effluents toxicity was performed by acute toxicity tests using Daphnia magna as test organism. The results revealed that the two-stage anaerobic system was more stable than the one-stage system for both real and the synthetic dyes Congo Red (CR) and Reactive Black 5 (RB5), and more efficient for the dye RR2 in absence of AQDS. However, in the presence of AQDS, color removal efficiency of RR2 was higher for both systems, masking the effect of phase separation. For real textile wastewater, it was not observed any effect of the AQDS application on R3, even when a short HRT or low electron donor concentration was applied. The aerobic and AOP post-treatments were able to reduce the effluents COD to values lower than the limits defined at the Legislation n 154 of SEMACE. The UV/H2O2 AOP-type was effective in removing color and COD from both real and synthetic textile effluents. The acute toxicity tests revealed the toxic potential of textile effluents and their by-products as well as the aromatic amines mineralization in anaerobic/aerobic systems.

O efluente fenólico em estudo apresenta a relação DBO5/DQO (Demanda Bioquímica de Oxigênio/ Demanda Química de Oxigênio) igual a 0,15, ou seja caracteriza-se por ser um efluente não biodegradável. No tratamento inicial do efluente utilizou-se ozônio, na presença do sal de ferro II proveniente da solução de sulfato ferroso heptaidratado 0,82 mol. L-1 e do peróxido de hidrogênio , que possui a finalidade catalítica na formação dos radicais hidroxilas, com alto poder de oxidação da matéria orgânica. Nesta etapa foi estudado a união dos processos oxidativos O3/UV e Foto-Fenton, Foram tratados 3 L do efluente fenólico in natura em um reator fotocatalítico com lâmpada ultravioleta. Em todos os experimentos o pH e a temperatura do meio reacional foram controlados. Os experimentos foram executados segundo um planejamento de Taguchi L16, no qual a variável entrada de maior importância para a degradação da matéria orgânica foi o peróxido de hidrogênio. As variáveis respostas analisadas foram a concentração do Carbono Orgânico Total, Demanda Química de Oxigênio e Fenóis Totais. No planejamento de Taguchi L16 foram selecionadas as variáveis significativas para o processo de degradação do efluente fenólico, a fim de serem otimizadas através do Método de Superfície de Resposta (MSR Foto-Fenton e O3/UV). O método de otimização MSR Foto-Fenton foi eficiente na degradação do composto fenólico, sendo assim a melhor condição experimental da planilha de otimização foi a de número 10 e corresponde a uma redução de COT= 54,68%, DQO=78,73% e Fenois Totais= 98,1%. Os parâmetros controlados do processo para essa condição foram: pH=3, temperatura de 30 ºC, potência ultravioleta de 28 W e reagente Fenton (H2O2= 48,3g e Fe+2 =5,95g), que corresponde a relação mássica H2O2 /Fe+2 igual a 8.
The phenolic effluent in this study has the rate DBO5/DQO (Biochemical Oxygen Demand / Biochemical Oxygen Demand) equal to 0.15, which is characterized by an effluent to be non-biodegradable. In the initial treatment of phenol was used ozone in the presence of iron salt II from the solution of ferrous sulfate heptahydrate 0.82 mol. L-1 and hydrogen peroxide, which has the purpose in the catalytic formation of hydroxyl radicals with high oxidation power of organic matter. In this stage, was studied the union of the oxidative process O3/UV and Photo-Fenton. The effluent was treated about 3 L about in a photocatalytic reactor with UV lamp. In all experiments, the pH and temperature of the reaction medium were control. The experiments are being carried out to a Taguchi L16 design, in which the input variable of greatest importance to the degradation of organic matter was hydrogen peroxide. The response variable analyzed was given by the concentration of Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) and Total Phenols (FT). In planning Taguchi L16 significant variables were selected for the degradation process of phenolic wastewater in with purpose of to be optimized by Response Surface Method (RSM Photo-Fenton and O3/UV). The optimization method was efficient photo-Fenton degradation of phenolic compound, so the best experimental condition spreadsheet optimization was the number 10 and corresponds to a reduction of TOC = 54.68%, COD = 78,73% and Total Phenols= 98.1%. The controlled process parameters for this condition were: pH = 3, temperature of 30 ° C, power of 28 W ultraviolet and Fenton reagent (H2O2= 48,3g and Fe+2 = 5,95g), corresponding to mass ratio H2O2 / Fe +2 = 8.

O Fenol e compostos fenolicos foram classificados como poluentes primarios pela Environmental Protection Agency (EPA USA). Eles sao geralmente encontrados em efluentes industriais como: poupa e papel; madeireiras; plasticos e polimeros sinteticos; farmaceuticos, pesticidas, oleo e petroquimicas. Os tratamentos de agua convencionais tem mostrado ineficiencia em altas concentracoes de fenol. Este trabalho visa o tratamento de solucao aquosa de fenol via Processos Oxidativos Avancados (POAs) com o objetivo de aumentar a biodegradabilidade possibilitando a aplicacao de um processo convencional (lodos ativados) como pos-tratamento. O pre-tratamento e usado para modificar a estrutura do fenol levando-o a seus subprodutos como substancias aromaticas e acidos carboxilicos. Os experimentos mostraram a eficiencia do pre-tratamento atraves do parametro de biodegradabilidade (DBO5/DQO) apresentando 0,19 em 30 min de reacao foto- Fenton, com concentracao inicial de fenol de 1000 mg.L-1 de Carbono Organico Total (TOC), 1 mmol.L-1 de FeSO4 e 100 mmol.L-1 de H2O2, dosado durante 2 horas de reacao. Apos pre-tratada fotoquimicamente, esta mesma solucao foi utilizada como fonte de carbono em um sistema continuo de lodos ativados para remocao da materia organica residual, apresentando reducao de 92% do TOC inicial. Estes resultados evidenciam a eficiencia da integracao entre os processos foto-Fenton e lodo ativado no tratamento de efluentes contendo compostos recalcitrantes.
Phenol and phenolic compounds have been listed as priority-pollutants by the Environmental Protection Agency (EPA USA). They are often found in industrial effluents such as from pulp and paper, timber, plastics and synthetic polymer, pharmaceutical, pesticide, oil and petrochemical industries. Most of the traditional wastewater treatments have shown inefficiency against high phenol concentrations. This work aims to treat phenol solution via Advanced Oxidation Processes (AOP´s) to enhance medium biodegradability and using it as an effluent in a continuous activated sludge process. The purpose of the pre treatment is to modify the phenol structure leading it to its byproducts such as aromatics compounds and carboxylic acids. The experiments have shown the effectiveness of the pre-treatment by the biodegradability parameter BOD5/COD which was achieved 0,19 at 30 min of photo- Fenton reaction with a initial phenol concentration of 1000 mg.L-1 of TOC, 1 mmol.L-1 of FeSO4 and 100 mmol.L-1 of H2O2, added with a peristaltic pump along 2 hours of reaction. After the photochemical pre treatment, the same solution was used as a carbon source in a continuous activated sludge system for removing residual organic matter, with a reduction of 92% of the TOC initial. Those results have shown the efficiency when integrating photo-Fenton and activated sludge processes on the treatment of effluents containing recalcitrant organic compounds.

Orientador: Wilson de Figueiredo Jardim
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado
Quimica Analitica
Mestre em Química

Les eaux usées issues de l’industrie pétrochimique contiennent des composés organiques peu ou pas biodégradables dont le traitement nécessite de faire appel à des nouvelles techniques de traitement sophistiquées. L’objectif de ce travail est d’étudier le rôle d’adsorbants alumino-silicatés dans un procédé d’oxydation avancée associant, dans un même réacteur, adsorption et oxydation à l’ozone pour le traitement de ce type d’effluents. Dans un premier temps, l’étude s’est centrée sur l’évaluation des performances du procédé pour l’élimination d’une molécule modèle, le 2,4-diméthylphénol, dans un réacteur agité semi-batch. Avant de coupler l’ozonation et l’adsorption, chacun des phénomènes mis en jeu a été étudié indépendamment, ce qui a permis la compréhension des mécanismes qui régissent le couplage. Deux modes de couplage ont été testés, un traitement simultané ozonation/adsorption et un traitement séquentiel ozonation puis adsorption. Dans les deux configurations, l’ajout des matériaux alumino-silicatés a eu un effet très limité sur la cinétique globale de dégradation de la molécule modèle. Par contre, l’ajout des matériaux a un effet très marqué sur la cinétique d’élimination du COT, principalement dû à un effet d’adsorption de sous-produits d’oxydation spécifiques. Il a aussi été démontré que la restauration des propriétés du solide est possible, permettant ainsi sa réutilisation. Dans un second temps, le procédé a été appliqué au traitement d’un effluent réel rejeté par une usine pétrochimique chinoise, en suivant la même démarche que celle adoptée lors de l’étude réalisée sur la molécule modèle et en utilisant un réacteur à lit fluidisé semi-batch. Les mêmes phénomènes ont été observés, confirmant l’efficacité de ce procédé pour le traitement des eaux usées pétrochimiques.

Orientador: Jose Roberto Guimaraes, Pedro Sergio Fadini
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil
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Resumo: Nesse trabalho foram realizados ensaios de tratabilidade de soluções e efluentes contendo formol conjugando-se processos físico-químicos com biológicos. Dentre os vários processos, o UV/H2O2 foi o que apresentou a melhor eficácia no tratamento do efluente do Laboratório de Anatomia/IB-UNICAMP. A redução dos teores de CH2O, COD, DQO e DBO, foram 91, 48, 46 e 53 % para o UV/H2O2 e, 94, 38, 38 e 43 % para o Foto-Fenton, respectivamente, ao final de 420 minutos de ensaio. Para uma solução de formol com concentração inicial de 12.000 mg L-1, as reduções de COD foram de 65 e 61 %, para Foto-Fenton e UV/H2O2, respectivamente, ao final de 390 minutos de ensaio. Para soluções com 400 mg L-1 em formol as redu?es em COD foram 65 e 98 % nos processos Foto-Fenton e UV/H2O2, respectivamente, em ensaios com 120 minutos de duração. O sistema Lodo Ativado por Batelada convencional (?c 7 dias) apresentou reduções nos valores de COD, DQO e DBO de 88, 83 e 96 % e 88, 86 e 98 % para sistemas com aeração prolongada (?c 20 dias), alimentados com efluente tratado por POA
Abstract: In this work assays of treatment of solutions had been carried through and effluent I contend formaldehyde conjugating processes physicist-chemistries with biological. Amongst the some processes, the UV/H2O2 was what it presented the best efficiency in the treatment of the effluent one of the "Laboratorio de Anatomia/IB-UNICAMP. The reduction of the values of the CH2O, COD, DQO and DBO, had been 91, 48, 46 and 53 % for the UV/H2O2 and, 94, 38, 38 and 43 % for Photo- Fenton, in the 420 minutes of assay, respectively. Solution of formaldehyde with initial concentration of 12.000 mg L-1, the TOC reductions had been of 65 and 61 %, for Photo-Fenton and UV/H2O2, respectively, for 390 minutes of assay. For solutions with 400 mg L-1 in formaldehyde the reductions in TOC had been 65 and 98 % in processes Photo-Fenton and UV/H2O2, respectively, for 120 minutes of assay. Systems Activated Sludge had presented reductions in the values of TOC, COD and BOD of 88, 83 and 96 % for conventional systems (?c 7 days) and 88, 86 and 98 % for systems with drawn out aeration (?c 20 days), using effluent treated by POA
Doutorado
Saneamento e Ambiente
Doutor em Engenharia Civil

In this dissertation, as a monitoring technology for cyanotoxins, a multiwalled carbon nanotube (MWCNT)-based electrochemical biosensor was developed to determine microcystin-LR (MC-LR), a potent cyanobacterial toxin, in sources of drinking water supplies. The performance of the MWCNT array biosensor is evaluated using micro-Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, optical microscopy, and Faradaic electrochemical impedance spectroscopy. A linear dependence of the electron-transfer resistance on the MC-LR concentration is observed in the range of 0.05 to 20 µg L^-1, which enables cyanotoxin monitoring well below the World Health Organization provisional concentration limit of 1 µg L^-1 for MC-LR in drinking water.

In addition to the development of monitoring tools for cyanotoxins, visible light-activated (VLA) TiO₂ and monodisperse TiO₂ were developed and evaluated for treatment of water contaminants of emerging concern. These materials were synthesized using modified sol-gel methods (i.e., wet chemistry-based methods) such as self-assembly-based and ionic strength-assisted techniques. For this study, first, VLA-sulfur-doped TiO₂ (S-TiO ₂) nanocrystalline films were synthesized by a self-assembly-based sol-gel method using nonionic surfactant to control nanostructure and an inorganic sulfur source for decomposing MC-LR under visible light illumination. Second, the effects of solvent on the synthesis of VLA-S-TiO₂ films were scrutinized. Four different polar, protic solvents, isopropanol, 1-butanol, ethanol, and methanol, were chosen as the solvent in four titania sol-gel preparations. Third, monodisperse anatase titania nanoparticles with controllable sizes (typically 10-300 nm) were synthesized using an efficient and straightforward protocol via fine tuning of the ionic strength in the devised sol-gel methodology. Finally, noble metal Ag-decorated, monodisperse TiO₂ (TiO ₂-Ag) aggregates were successfully synthesized by an ionic strength-assisted, simple sol-gel method and were used for the photocatalytic degradation of the pharmaceutical oxytetracycline (OTC) under both UV and visible light irradiation. With a self-assembly-based sol-gel method, nanostructured anatase S-TiO ₂ with high surface area (> 100 m² g^-1) and porosity (> 30 %) was synthesized and the sample calcined at 350 ^oC demonstrated the highest visible light absorption and visible light-induced photocatalytic activity in the decomposition of MC-LR. The structural and morphological properties of S-TiO₂ could be also tailor-designed using different solvents in the sol-gel synthesis, while inducing negligible effects on the sulfur doping and the visible light activation of TiO ₂. Thus, it can be concluded that the enhancement of photocatalytic activity of S-TiO₂ films can be achieved by judicious choice of the main solvent for the sol-gel method. With an ionic strength-assisted sol-gel method, monodisperse spherical anatase TiO₂ (10-300 nm in diameter) as well as monodisperse TiO₂-Ag aggregates with 350 nm of diameter were synthesized. For TiO₂-Ag, its visible light absorption increased due to the presence of Ag on the surface of monodisperse TiO₂, which resulted in the enhancement of the photocatalytic degradation of OTC under both UV-visible light and visible light irradiation compared to pure TiO₂. There was an optimal Ag content to obtain the highest photocatalytic degradation of OTC. These newly developed materials demonstrated the efficient decomposition of water contaminants of emerging concern, especially MC-LR and OTC, under UV-visible light and visible light illumination.

L'adsorption sur charbon actif est une technique relativement répandue de post-traitement des effluents aqueux. Cependant il ne s'agit pas d'un traitement ultime, puisque les polluants restent concentrés sur la surface solide. Des techniques de régénération doivent donc être mises en œuvre. C'est dans ce contexte qu'ont été étudiés ici les procédés d'oxydation avancée Fenton et photo-Fenton, dont l'efficacité est reconnue pour éliminer la pollution organique. Plus précisément, l'objet de cette thèse est l'étude sur plusieurs cycles consécutifs de l'adsorption du phénol sur charbon actif et de la régénération in-situ de l'adsorbant par oxydation (photo)Fenton. Deux charbons actifs différents ont été étudiés : le premier à la fois micro et mésoporeux (PICA L27) et le second essentiellement microporeux (PICA S23). Deux séries d'expériences ont été ainsi réalisées : 1) d'abord en réacteur agité (adsorption et oxydation en mode batch), 2) puis dans des conditions plus proches du procédé réel, avec une adsorption continue en lit fixe, suivie de l'oxydation batch par recirculation du réactif Fenton au travers du lit saturé. Dans le premier cas, les effets de la concentration en Fe2+ et en H2O2 ont été analysés, montrant que les conditions optimales pour l'oxydation homogène du phénol (sans charbon) ne sont pas les meilleures pour la régénération du charbon saturé par le polluant : une réduction continue de la capacité d'adsorption du L27, de 100% à 23%, est observée après 3 oxydations, en raison de la consommation du charbon et de la diminution de sa surface spécifique. Par contre, une concentration plus élevée de Fe2+ et plus faible de H2O2 (2 fois la stœchiométrie) permettent de retrouver 50% de la capacité initiale d'adsorption pendant au moins 4 cycles consécutifs. Comme il a été vu dans des études précédentes utilisant l'oxydation à l'air (sous température et pression), l'efficacité de régénération est aussi bien plus faible pour le S23 (autour de 20%). Des résultats similaires ont été obtenus sur le réacteur à lit fixe avec recirculation. Durant l'oxydation, le taux de conversion du Carbone Organique Total en phase liquide a atteint à chaque fois une valeur limite, probablement du fait de la formation de complexes entre le fer et les acides carboxyliques produits. L'utilisation de l'irradiation UV, qui est connue pour décomposer ces complexes, a conduit à une minéralisation quasi-totale et a amélioré l'efficacité de régénération du charbon, jusqu'à 56% de la capacité initiale après 2 cycles (contre 40% pour l'oxydation Fenton simple)
Adsorption on activated carbon (AC) is a technique extensively applied for wastewater treatment. However adsorption alone is not an ultimate solution, since the pollutants are just immobilized on the carbon surface. There is thus a need for efficient regeneration techniques. In this context, Fenton and photo-Fenton oxidations, which are promising technologies to destroy organic pollution, have been tested to regenerate the AC. The purposes of this study are the adsorption of phenol on activated carbons and the consecutive in-situ regeneration of carbon by (photo-) Fenton oxidation. Two different operations have been carried out: 1) batch procedure in order to investigate the influence of Fe2+ and H2O2 concentrations; 2) continuous fixed bed adsorption, followed by a batch circulation of the Fenton’s reagent through the saturated AC bed, to examine the efficiency of the real process. Two different activated carbons have been also studied: a both micro- and mesoporous AC (PICA L27) and an only microporous one (PICA S23). In the batch reactor the best conditions found for pollutant mineralization in the homogeneous Fenton system are not the best for AC regeneration: a continuous reduction of adsorption capacity of L27 is observed after 3 oxidations, due to the decrease of both AC weight and surface area. Higher concentration of Fe2+ and lower concentration of H2O2 (2 times the stoechiometry) lead to a 50% recovery of the initial adsorption capacity during at least 4 consecutive cycles for L27, while about 20% for S23. In the consecutive continuous adsorption/batch Fenton oxidation process, the regeneration efficiency reaches 30% to 40% for L27 after two cycles whatever the feed concentration and less than 10% for S23. A photo-Fenton test performed on L27 shows almost complete mineralization (contrary to dark Fenton) and further improves recovery of AC adsorption capacity although not complete (56% after two cycles)

L'installation de décharges sanitaires représente la seule méthode de stockage des déchets ménagers solides dans plusieurs pays. Les lixiviats générés à partir de ces décharges présentent une grande toxicité aigüe et chronique. Lorsqu'ils ne sont pas traités, ces lixiviats peuvent pénétrer dans la nappe phréatique ou contaminer les eaux de surface et donc contribuer à la pollution des eaux. Divers procédés biologiques ont été appliqués au traitement des lixiviats de décharge. Cependant, ces procédés sont relativement inefficaces pour le traitement des lixiviats à cause de la présence de composés bioréfractaires. Les procédés d'oxydation avancée représentent une excellente alternative pour le traitement des eaux polluées par les polluants toxiques et/ou persistants (biorfractaires). Dans ce travail, quelques procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués au traitement de deux molécules modèles appartenant chacune à une famille de polluants présents dans la matrice du lixiviat tunisien de la décharge contrôlée de Jebel Chakir (identifiée dans ce travail), à savoir, l'anhydride phtalique et le 8-hydroxyquinoléine sulfate. Pour ces deux molécules, une étude de la dégradation et la minéralisation a été réalisée en optimisant les paramètres expérimentaux. L'étude cinétique montre que la dégradation oxydative des deux polluants étudiés suit une cinétique de réaction du pseudo-premier ordre, avec des temps de dégradation assez courts. Par exemple, avec une anode de Pt, l'oxydation complète de l'anhydride phtalique a été achevée en moins de 15 min sous un courant appliqué de 2,88 mA cm-2. L'identification des intermédiaires aromatiques et carboxyliques à courte chaine carbonée a permis de proposer un mécanisme de dégradation de l'anhydride phtalique par les radicaux hydroxyles. Les valeurs des constantes de vitesse des réactions entre les •OH, et les deux polluants et leurs intermédiaires ont été déterminés par la technique de cinétique de compétition à l'aide d'un composé de référence ; l'acide 4-hydroxybenzoϊque. Le suivi de la toxicité lors du traitement de la solution de 8-HQS par la méthode Microtox®, (une méthode basée sur la mesure de la luminescence des bactéries marines Vibriofischeri) a montré la formation des intermédiaires plus toxiques que les molécules mères. Une comparaison des procédés d'oxydation avancée appliqués a été réalisée pour chacun des polluants. Enfin, différents procédés d'oxydation avancée (procédé Glidarc, électro-Fenton, oxydation anodique et photo-Fenton) ont été appliqués à la dépollution du lixiviat tunisien de Jebel Chakir. Une étude comparative a été réalisée afin d'évaluer le coût des procédés. L'ensemble des résultats obtenus confirme l'efficacité du procédé électro-Fenton pour la dépollution des lixiviats
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Heterogeneous photocatalysis is an advanced oxidation technology widely applied in environmental remediation processes. It is a relatively safe and affordable technology with a low impact on the environment and has found applications in a number of fields from chemical engineering, construction and microbiology to medicine. It is not catalysis in the real sense of the word as the photons which initiate the desired photocatalytic reaction are consumed in the process. The cost of these photons is by far the limiting economic factor in its application. From a technical standpoint, the inefficient use of the aforementioned photons during the photocatalytic reaction is responsible for the limited adoption of its application in industry. This inefficiency is characterised by low quantum yields or photonic efficiencies during its application. The mechanism of the technique of controlled periodic illumination which was previously proposed as a way of enhancing the low photonic efficiency of TiO2 photocatalysis has been investigated using a novel controlled experimental approach; the results showed no advantage of periodic illumination over continuous illumination at equivalent photon flux. When the technique of controlled periodic illumination is applied in a photocatalytic reaction where attraction between substrate molecules and catalyst surface is maximum and photo-oxidation by surface-trapped holes, {TiIVOH•}+ ads is predominant, photonic efficiency is significantly improved. For immobilized reactors which usually have a lower illuminated surface area per unit volume compared to suspended catalyst and mass transfer limitations, the photonic efficiency is even lower. A novel photocatalytic impeller reactor was designed to investigate photonic efficiency in gas–solid photocatalysis of aromatic volatile organic compounds. The results indicate photonic efficiency is a function of mass transfer and catalyst deactivation rate. The development of future reactors which can optimise the use of photons and maximize photonic efficiency is important for the widespread adoption of heterogeneous photocatalysis by industry.