Trichloroethylene (TCE) is one of the most common groundwater pollutants in the United States. The EPA estimated that between 9% and 34% of the drinking water sources in the United States may contain TCE. The United States Environmental Protection Agency set a maximum contaminant level at 5 µg/L of trichloroethylene for drinking water. This study investigated the feasibility of removing TCE from water by sorption to ZSM-5 and advanced oxidation to destroy the TCE on the zeolite. Aqueous oxidation of TCE with Fenton's reagent was shown to be efficient for the destruction of TCE. The quantified by-products were cis-DCE and trans-DCE. ZSM-5 rapidly removed TCE from water. A Freundlich isotherm was created for the uptake of TCE by ZSM-5. Once TCE was sorbed to ZSM-5, preliminary experiments showed that the oxidation was able to destroy the TCE while producing the same by-products.

Natural organic matter (NOM) occurs ubiquitously in drinking water supplies and is problematic since it serves as a precursor to disinfection by-products (DBPs) formation. Stricter DBP regulations will drive utilities to consider advanced treatment processes for DBP control through NOM removal. Herein, the transformation of NOM in homogeneous (UVA/H2O2 and UVA/Fe/H2O2) and heterogeneous (UVA/TiO2) Advanced Oxidation Processes (AOPs) were studied. Organic matter from three different sources was investigated in this work, specifically a commercial humic acid, and two Australian surface water sources. The transformation of the organic matter as a result of oxidation was investigated through multiple analytical techniques, such as UV-Vis spectroscopy, DOC analysis, high performance size exclusion chromatography (HPSEC), resin fractionation, liquid chromatography with organic carbon detection (LC-OCD) and disinfection byproducts formation potential. The multi-analysis approach is required due to the complex and heterogeneous nature of NOM. Each analytical technique provides complementary information on different properties of NOM, leading to a comprehensive understanding on how AOPs transform the chemical and physical properties of NOM. Both homogeneous and heterogeneous AOPs were found to be effective for NOM removal. However, complete mineralisation was not achieved, even under prolonged irradiation. Large aromatic and hydrophobic organics were degraded into lower molecular weight hydrophilic compounds, which had weak UV absorbance at 254 nm. In the UVA/TiO2 treatment, multi-wavelength HPSEC analysis demonstrated the formation of low molecular weight compounds with strong absorbance at wavelength lower than 230 nm. These residual organic compounds, though recalcitrant, had a low reactivity to chlorine to form THMs, and were identified to be low molecular weight acids and neutral compounds from LC-OCD analysis. Finally, the current work reports the novel synthesis of magnetic photocatalyst for NOM oxidation from low cost precursors to solve the separation problem of nano-sized particles. Magnetite particles were coated with a layer of protective silica from sodium silicate precursor. Photoactive titanium dioxide was then deposited onto the silica coated particles using titanium tetrachloride precursor. The as-prepared magnetic photocatalyst exhibited excellent stability and durability. Although the photoactivity of the magnetic photocatalyst is lower than commercial TiO2 photocatalyst, it can be easily recovered by magnetic field.

In the last years, due to an increasing concern about the possible harmful effects of the gas emissions of the continuous gasoline use, their compositions have changed considerably. The lead additives ban and the aromatic compounds content limitation has caused the worldwide expansion of the use of fuel oxygenates. These compounds are mainly molecules with an atom of oxygen inside its structure. Usually they are ethers or alcohols. The most used worldwide is methyl tert-butyl ether (MTBE) followed by ethyl tert-butyl ether (ETBE). These compounds because of their physical and chemical properties have become persistent and recalcitrant pollutants in the groundwaters of the entire world.Due to the problem generate by the contamination of water resources is important to go deeper in the knowledge of the behaviour of fuel oxygenates in the environment in order to obtain tools that let us model and study their environmental dispersion and remediation. This doctoral thesis offers an important thermodynamical study of these compounds and analyzes different remediation techniques.The work is structured in four chapter well differentiated. The first one consists of an introduction to the problem, the current situation of thermodynamical information and the existent techniques for the water treatment.The second chapter is focused on obtaining and improving the thermodynamical information. It is studied how temperature affect to the interactions of fuel oxygenates with different gasoline compounds such us BTEX (benzene, toluene, ethylbenzene and xylenes), alcans or degradation products like tert-butyl alcohol. In this chapter is included new thermodynamical information in terms of physical properties (density and speed of sound), vapor-liquid equilibria and liquid-liquid equilibria (as water solubility). As a result have been characterized 25 binary systems and their pure compounds in terms of physical property, 3 vapor liquid equilibria and finally the study of water solubility of the ethers most used in gasoline blending as temperature function.The third chapter is focused from a technological point of view. Here it is studied thermodynamically, different conventional remediation techniques fort he MTBE and ETBE like the adsorption onto activated carbon and batch air stripping. It is observed that the temperature increases the efficiency in both processes and that ETBE is easier treated. On the other hand, it has been analyzed the use of new solvents, in this case ionic liquids, in order to dehydrate fuel oxygenates obtaining satisfactory results. Finally, studies of advanced oxidation processes have been carried out using Fe-zeolites as catalyst. The use of these materials let oxidize MTBE and their most problematic degradation products, like tert-butyl alcohol and tert-butyl formate at environmental conditions and neutral pH in reasonable times.Finally in the fourth and last chapter are summarized the conclusions obtained during the development of this work and the research directions to follow in the future. / En els darrers anys, degut a una creixent preocupació sobre els possibles efectes nocius de les emissions de gasos procedents de l'ús continu de gasolines, la composició d'aquestes ha patit canvis importants. La prohibició dels additius amb plom així com la limitació de compostos aromàtics han donat lloc a una gran expansió arreu del món de l'ús del que es coneixen com additius oxigenats de la gasolina. Aquest compostos son principalment molècules que tenen dins la seva estructura almenys un àtom d'oxigen. Normalment acostumen a ser èters o alcohols. De tots els més utilitzats a nivell mundial son el metil tert butil èter (MTBE), seguit pel etil tert butil èter (ETBE). Aquests compostos degut a les seves propietats físiques i químiques han esdevingut uns contaminants persistents i recalcitrants de les aigues a tot el món.Degut a la problemàtica generada per la contaminació del recursos hídrics és important aprofundir en el coneixement del seu comportament en el medi ambient per tal de obtenir eines que permetin modelitzar i estudiar tant la seva dispersió com la seva remediació. La present tesi doctoral ofereix un estudi termodinàmic important d'aquest compostos i estudia diferents tècniques de remediació.Aquest treball s'estructura en quatre capítols ben diferenciats. El primer d'ells consisteix en una introducció a la problemàtica, la situació actual de la informació física i química de la qual es disposa i de les tècniques existents per al tractament d'aigües contaminades.El segon capítol està enfocat a obtenir i millorar la informació termodinàmica. S'estudia com la temperatura afecta a les interaccions dels additius oxigenats amb diferents constituents de les benzines com son els BTEX(benzè, toluè, etilbenzè i xilens), alcans o compostos de degradació dels oxigenats com pot ser el tert butil alcohol. En aquest capítol s'aporta nova informació termodinàmica prèviament no reportada en la literatura en termes de propietat físiques (densitat i velocitat de so), equilibri vapor líquid i equilibri líquid líquid (en forma de solubilitat en aigua). Com a resultat d'aquest capítol cal remarcar la caracterització de 25 sistemes binaris i els seus compostos purs en termes de propietat física, 3 equilibris binaris líquid vapor i finalment l'estudi de la solubilitat dels èters més utilitzats com additius oxigenats com a funció de la temperatura.El tercer capítol està enfocat des d'un punt de vista tecnològic. En aquest s'estudia termodinàmicament diferent tècniques convencionals per l'eliminació de MTBE i ETBE com son l'adsorció en carbó actiu i l'aireació. S'observa que l'increment de la temperatura augmenta l'eficiència en tot dos processos i que l'ETBE es més fàcilment eliminat. Per altra banda s'ha analitzat l'ús de nous solvents, com son els líquids iònics, per tal de deshidratar additius oxigenats obtenint-se resultats satisfactoris. Finalment s'han realitzat estudis d'oxidació avançada utilitzant zeolites amb contingut fèrric. L'ús d'aquest materials permet oxidar l'MTBE i els seus compostos de degradació més problemàtics, com son el tert butil alcohol i el tert butil formiat en condicions ambientals i pH neutres en temps raonables.Finalment en el quart i últim capítol es resumeixen les conclusions obtingudes durant aquest treball i es donen ressenyes a seguir en investigacions futures en aquest camp.

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.

Natural organic matter (NOM) occurs ubiquitously in drinking water supplies and is problematic since it serves as a precursor to disinfection by-products (DBPs) formation. Stricter DBP regulations will drive utilities to consider advanced treatment processes for DBP control through NOM removal. Herein, the transformation of NOM in homogeneous (UVA/H2O2 and UVA/Fe/H2O2) and heterogeneous (UVA/TiO2) Advanced Oxidation Processes (AOPs) were studied. Organic matter from three different sources was investigated in this work, specifically a commercial humic acid, and two Australian surface water sources. The transformation of the organic matter as a result of oxidation was investigated through multiple analytical techniques, such as UV-Vis spectroscopy, DOC analysis, high performance size exclusion chromatography (HPSEC), resin fractionation, liquid chromatography with organic carbon detection (LC-OCD) and disinfection byproducts formation potential. The multi-analysis approach is required due to the complex and heterogeneous nature of NOM. Each analytical technique provides complementary information on different properties of NOM, leading to a comprehensive understanding on how AOPs transform the chemical and physical properties of NOM. Both homogeneous and heterogeneous AOPs were found to be effective for NOM removal. However, complete mineralisation was not achieved, even under prolonged irradiation. Large aromatic and hydrophobic organics were degraded into lower molecular weight hydrophilic compounds, which had weak UV absorbance at 254 nm. In the UVA/TiO2 treatment, multi-wavelength HPSEC analysis demonstrated the formation of low molecular weight compounds with strong absorbance at wavelength lower than 230 nm. These residual organic compounds, though recalcitrant, had a low reactivity to chlorine to form THMs, and were identified to be low molecular weight acids and neutral compounds from LC-OCD analysis. Finally, the current work reports the novel synthesis of magnetic photocatalyst for NOM oxidation from low cost precursors to solve the separation problem of nano-sized particles. Magnetite particles were coated with a layer of protective silica from sodium silicate precursor. Photoactive titanium dioxide was then deposited onto the silica coated particles using titanium tetrachloride precursor. The as-prepared magnetic photocatalyst exhibited excellent stability and durability. Although the photoactivity of the magnetic photocatalyst is lower than commercial TiO2 photocatalyst, it can be easily recovered by magnetic field.

A crescente eutrofização dos ambientes aquáticos é consequência das atividades humanas que desequilibram os ecossistemas. A descarga de esgotos urbanos, a utilização de adubos químicos, os efluentes das agroindústrias e dos diversos setores industriais promovem a entrada de quantidades significativas de nutrientes e matéria orgânica em corpos d´água, favorecendo o aumento das florações de algas, entre elas as cianobactérias. O excesso de matéria orgânica e os despejos de efluentes agroindustriais nos mananciais hídricos representam os principais fatores do excesso de floração das cianobactérias, destacando-se a Microcystis aeruginosa e da sua cianotoxina microcistina. Nesta tese foi aplicado o Processo Oxidativo Avançado (POA) de Fotoeletroxidação (FEO) para a degradação de Microcystis aeruginosa e da cianotoxina microcistina. Investigou-se a otimização de parâmetros como tempo de tratamento e intensidade de corrente elétrica aplicada. Os resultados obtidos nas condições aplicadas demonstram valores de 99% para a degradação de Microcystis aeruginosa e cianotoxina Microcistina com o tempo de 10min e densidade de corrente de 2mA.cm-2. Os testes de toxicidade aguda com ajuste de pH de 6,3 para 7,3 não apresentaram toxidade para a espécie teste Pimephales promelas. / The increasing eutrophication of aquatic environments is a consequence of human activities that disrupt ecosystems. The discharge of urban sewage, the use of chemical fertilizers, effluents from agro-industries and other industrial sectors promote the input of significant amounts of nutrients and organic matter in water, favoring increased blooms of algae, including cyanobacteria. Excessive organic matter and the discharge of agroindustrial effluents in the water bodies, represent the main factors for the excessive bloom of cyanobacteria, especially Microcystis aeruginosa and microcystin cianotoxin. In this study, an Advanced Oxidation Process named photoelectrooxidation, was used to the degradation of Microcystis aeruginosa and cianotoxin microcystin. The optimization of parameters such as, treatment time and intensity of electrical current applied in the process of PEO were evaluated. The results achieved under the conditions applied, show 99% of degradation with experimental times at 10 minutes and a current density of 2mA.cm-2. The acute toxicity tests, with pH adjustment from 6.3 to 7.3, did not show toxicity to the species Pimephales promelas.

A crescente eutrofização dos ambientes aquáticos é consequência das atividades humanas que desequilibram os ecossistemas. A descarga de esgotos urbanos, a utilização de adubos químicos, os efluentes das agroindústrias e dos diversos setores industriais promovem a entrada de quantidades significativas de nutrientes e matéria orgânica em corpos d´água, favorecendo o aumento das florações de algas, entre elas as cianobactérias. O excesso de matéria orgânica e os despejos de efluentes agroindustriais nos mananciais hídricos representam os principais fatores do excesso de floração das cianobactérias, destacando-se a Microcystis aeruginosa e da sua cianotoxina microcistina. Nesta tese foi aplicado o Processo Oxidativo Avançado (POA) de Fotoeletroxidação (FEO) para a degradação de Microcystis aeruginosa e da cianotoxina microcistina. Investigou-se a otimização de parâmetros como tempo de tratamento e intensidade de corrente elétrica aplicada. Os resultados obtidos nas condições aplicadas demonstram valores de 99% para a degradação de Microcystis aeruginosa e cianotoxina Microcistina com o tempo de 10min e densidade de corrente de 2mA.cm-2. Os testes de toxicidade aguda com ajuste de pH de 6,3 para 7,3 não apresentaram toxidade para a espécie teste Pimephales promelas. / The increasing eutrophication of aquatic environments is a consequence of human activities that disrupt ecosystems. The discharge of urban sewage, the use of chemical fertilizers, effluents from agro-industries and other industrial sectors promote the input of significant amounts of nutrients and organic matter in water, favoring increased blooms of algae, including cyanobacteria. Excessive organic matter and the discharge of agroindustrial effluents in the water bodies, represent the main factors for the excessive bloom of cyanobacteria, especially Microcystis aeruginosa and microcystin cianotoxin. In this study, an Advanced Oxidation Process named photoelectrooxidation, was used to the degradation of Microcystis aeruginosa and cianotoxin microcystin. The optimization of parameters such as, treatment time and intensity of electrical current applied in the process of PEO were evaluated. The results achieved under the conditions applied, show 99% of degradation with experimental times at 10 minutes and a current density of 2mA.cm-2. The acute toxicity tests, with pH adjustment from 6.3 to 7.3, did not show toxicity to the species Pimephales promelas.

Advanced oxidation processes (AOPs) are commonly used for the destruction of persistent trace organic contaminants (TOrCs) that survive conventional wastewater treatment processes. Three types of AOPs, UV/H2O2, sunlight photolysis and photo-Fenton are experimentally investigated and mathematically quantified to anticipate the fate of TOrCs during oxidation processes, specifically addressing the significant effect of reaction by-products and water matrix on oxidation efficiencies. Hydrogen peroxide UV photolysis is among the most widely used AOPs for the destruction of TOrCs in waters destined for reuse. Previous kinetic models of UV/H2O2 focus on the dynamics of hydroxyl radical production and consumption, as well as the reaction of the target organic with hydroxyl radicals. In this work, we build a predictive kinetic model for the destruction of p-cresol by hydrogen peroxide photolysis based on a complete reaction mechanism that includes reactions of intermediates with hydroxyl radicals. The results show that development of a predictive kinetic model to evaluate process performance requires consideration of the complete reaction mechanism, including reactions of intermediates with hydroxyl radicals. Applying the model to an annular flow-through reactor with reflecting walls, the model mathematically demonstrates that the wall reflectivity significantly enhances the rate of conversion of the target, accounting for the UV light reflection from the reacting walls, as well as the hydrodynamics of the annular flow. Direct and indirect sunlight photolysis is critically important in the breakdown of contaminants in effluent wastewater. The fate of a suite of TOrCs and estrogenic activity were investigated in an effluent-dependent stream. Some TOrCs, which are not sufficiently attenuated through biodegradation and soil adsorption were destructed obviously with distance of travel in the stream. Independent experiments, conducted in batch reactor with 17α-ethinylestradiol (EE2) spiked in effluent showed that attenuation of estrogenic compounds maybe due in part to indirect photolysis caused by formation of reactive species from sunlight absorption. Further investigation was conducted using selective probe compounds to characterize reactive species. And results showed that singlet oxygen generated from excited state of effluent organic matter was responsible for essentially all observed transformations of targets in the effluent in Tucson. To mathematically quantify the photo-Fenton AOP, a kinetic model is proposed for the photolysis of Fe3+ hydroxo complexes at low pH (pH ≤ 3.0). The model incorporates elementary reactions of the Fenton-like and UV/H2O2 system. Iron speciation and photochemical parameters, including the molar absorptivities of light-absorbing species and the quantum yields of Fe3+ and FeOH2+ hydrolysis are experimentally validated. However, the predicted, time-dependent Fe2+ concentrations during Fe3+ photolysis are much lower than measured. The possible missing elements in the model could be (i) quenching of OH radicals by unknown species, or/and (ii) shielding of Fe2+ by unknown compounds at the beginning of the process.

Master of Science / Department of Biological & Agricultural Engineering / Stacy L. Hutchinson / As an alternative to traditional disinfection methods, the use of an advanced oxidation process (AOP) was investigated for exercise in theatre to expediate water usability. The system utilized for this study was a mobile combination of UV irradiation and ozonation, which provided multiple mechanisms for treatment without the addition of chemicals. As a compact and transportable apparatus, the proposed unit would treat water for secondary purposes including vehicle washing, equipment cleaning, and other demands not involving consumption or personal hygiene. Several varying dilutions of hog farm lagoon water and military vehicle wash water were combined with microbial concentrations up to 9.10E+04 mpn/mL. The inoculant tested was Escherichia coli for frequency of occurrence and similarities to microbes of bioterrorism. The overall results for the AOP treatment do not indicate a connection between inactivation and suspended solids, but there does exist a significant relationship to contact time as indicated by changes in the flow rate. The experimental data showed a correlation to increased inactivation with lower flow rates. Although inactivation was not complete, the once through flow system could be adjusted to recirculate water for additional treatment. Due to time constraints additional testing was not possible, but the benefit could be examined in future research. The relationship of TSS to inactivation was not evident as inactivation occurred in similar distributions whether suspended solids were elevated or reduced.

A crescente eutrofização dos ambientes aquáticos é consequência das atividades humanas que desequilibram os ecossistemas. A descarga de esgotos urbanos, a utilização de adubos químicos, os efluentes das agroindústrias e dos diversos setores industriais promovem a entrada de quantidades significativas de nutrientes e matéria orgânica em corpos d´água, favorecendo o aumento das florações de algas, entre elas as cianobactérias. O excesso de matéria orgânica e os despejos de efluentes agroindustriais nos mananciais hídricos representam os principais fatores do excesso de floração das cianobactérias, destacando-se a Microcystis aeruginosa e da sua cianotoxina microcistina. Nesta tese foi aplicado o Processo Oxidativo Avançado (POA) de Fotoeletroxidação (FEO) para a degradação de Microcystis aeruginosa e da cianotoxina microcistina. Investigou-se a otimização de parâmetros como tempo de tratamento e intensidade de corrente elétrica aplicada. Os resultados obtidos nas condições aplicadas demonstram valores de 99% para a degradação de Microcystis aeruginosa e cianotoxina Microcistina com o tempo de 10min e densidade de corrente de 2mA.cm-2. Os testes de toxicidade aguda com ajuste de pH de 6,3 para 7,3 não apresentaram toxidade para a espécie teste Pimephales promelas. / The increasing eutrophication of aquatic environments is a consequence of human activities that disrupt ecosystems. The discharge of urban sewage, the use of chemical fertilizers, effluents from agro-industries and other industrial sectors promote the input of significant amounts of nutrients and organic matter in water, favoring increased blooms of algae, including cyanobacteria. Excessive organic matter and the discharge of agroindustrial effluents in the water bodies, represent the main factors for the excessive bloom of cyanobacteria, especially Microcystis aeruginosa and microcystin cianotoxin. In this study, an Advanced Oxidation Process named photoelectrooxidation, was used to the degradation of Microcystis aeruginosa and cianotoxin microcystin. The optimization of parameters such as, treatment time and intensity of electrical current applied in the process of PEO were evaluated. The results achieved under the conditions applied, show 99% of degradation with experimental times at 10 minutes and a current density of 2mA.cm-2. The acute toxicity tests, with pH adjustment from 6.3 to 7.3, did not show toxicity to the species Pimephales promelas.