Rozprawy doktorskie na temat „Anacrobic wastewater treatment processes”

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.

Water pollution is an alarming problem that endangers the health of all living beings. The textile industry is listed as one of the most contaminating industries, since in order to carry out its dyeing and finishing processes, it requires a large amount of water resources; by decades, this industry has used Advanced Oxidation Processes (AOPs), since they have several advantages (e. g. destruction of toxic substances, reduction of heavy metals, allowing their use in conjunction with other processes, among others). Among the AOPs, heterogeneous photocatalysis stands out for its high efficiency for the removal of contaminants, including azo dyes. In order to perform a photocatalytic process, it is necessary to have a photoreactor, which will require a photocatalyst and at least one light source that activates the catalyst. This type of photoreactors can present several problems, such as the use of high cost photocatalysts, the generation of toxic byproducts in some low photocatalysts, the high electrical consumption caused by the use of traditional lighting sources and even difficulties with the geometry of the photoreactors. Hence the scientific community has tried to optimize the photocatalytic processes, some scientists have worked in the generation of new photocatalysts to be able to use them in wavelengths generated by low cost lighting sources (e. g. visible light), nevertheless, which in many times it increases the price of the photocatalyst. Another approach is to reduce electricity consumption by opting for the replacement of traditional lamps with low consumption lighting, for example, LED lighting; However, this substitution is currently done arbitrarily, so sometimes some authors doubt the ability to use these sources in this type of process. Moreover, when trying to improve the lighting sources, the photoreactor can be altered, so it is important to take into account its characteristics in order to achieve a significant improvement. This thesis focuses on an optoelectronic optimization to improve the efficiency of the lighting sources used in photocatalytic reactors. For this, a methodology has been generated to calculate LED arrays using uniform irradiance models, this irradiance must be homogeneous, with enough energy to photoactivate the catalyst with the aim to replace the traditional lamps, avoiding the chemical alteration of the photocatalysts; Likewise, a photocatalytic reactor has been designed and implemented on a laboratory scale with ultraviolet illumination adjusted to its characteristics (i.e. geometry, dimensions, among others) to work with a low cost photocatalyst (TiO2) in the decolorization of wastewater with textile dyes. Finally, in-situ monitoring has been designed and implemented in order to analyze the decolorization of textile water, this type of monitoring avoids the collection of water samples during the process, without altering the geometry of the reactor or reducing the volume of treated water in the reactor.
La contaminación del agua es un problema alarmante que pone en peligro la salud de todos los seres vivos. La industria textil está catalogada como una de las industrias más contaminantes, puesto que para realizar sus procesos de teñido y acabado requieren de una gran cantidad de recursos hídricos; desde hace décadas esta industria ha usado los Procesos de Oxidación Avanzada (AOPs) al presentar diversas ventajas (e. g. destrucción de sustancias tóxicas, reducción de metales pesados, permitir su uso en conjunto con otros procesos, entre otros). Entre los AOPs, sobresale la fotocatálisis heterogénea, por su alta eficiencia para la remoción de contaminantes, incluidos los colorantes azoicos. Para realizar un proceso fotocatalítico, es necesario tener un fotorreactor, el cual requerirá de un fotocatalizador y al menos una fuente de iluminación que active el catalizador. Este tipo de fotorreactores pueden presentar diversos problemas, tales como, el uso fotocatalizadores de alto costo, la generación de subproductos tóxicos en algunos fotocatalizadores de bajo, el alto consumo eléctrico causado por la utilización de fuentes tradicionales de iluminación e incluso dificultades con la geometría de los fotorreactores. Por lo tanto la comunidad científica ha intentado optimizar los procesos fotocatalíticos, algunos científicos han trabajado en la generación de nuevos fotocatalizadores para poder utilizarlos en longitudes de onda generada por fuentes de iluminación de bajo coste (e. g. luz visible), no obstante, lo que en muchas ocasiones incrementa el precio del fotocatalizador. Otro enfoque se encuentra en la reducción del consumo eléctrico optando por la sustitución de las lámparas tradicionales por iluminación de bajo consumo, por ejemplo, iluminación LED; sin embargo, actualmente esta sustitución se realiza de manera arbitraria, por lo que en ocasiones algunos autores dudan de la capacidad de utilizar estas fuentes en este tipo de procesos. Además al intentar mejorar las fuentes de iluminación puede alterarse el fotorreactor, por lo que es importante tomar en consideración sus características para lograr una mejora significativa. Esta tesis se enfoca en una optimización optoelectrónica para mejorar la eficiencia de las fuentes de iluminación utilizadas en reactores fotocatalíticos. Para ello se ha generado una metodología para calcular arreglos de LEDs utilizando modelos de irradiancia uniforme, esta irradiancia debe ser homogénea, con energía suficiente para fotoactivar el catalizador y sustituir las lámparas tradicionales, evitando la alteración química de los fotocatalizadores; asimismo, se ha diseñado e implementado un reactor fotocatalítico a escala de laboratorio con iluminación ultravioleta ajustada a sus características (geometría, dimensiones, entre otros) para trabajar con un fotocatalizador de bajo coste (TiO2) en la decoloración de agua con colorantes textiles. Para finalizar se ha diseñado e implementado un sistema de monitorización in-situ para la decoloración de aguas teñidas, este tipo de monitorización evita la toma de muestras de durante el proceso, sin alterar la geometría del reactor ni disminuir el volumen de agua tratada del reactor.

This study focussed on extending and applying techniques to measure hydrodynamic characteristics in treatment units at sewage works. Use was made of tracer dye studies and a spreadsheet based analysis tool. The resulting infonnation about residence time, tank conguration and pathological behaviour was linked to other infonnation from respirometry and flow and load studies. Characterising the wastewater process will become increasingly important as the economic and compliance drivers in the operation of wastewater treatment facilities become increasingly pronounced. Case studies at Royton WWTW, Chorley WWTW, Preston WWTW and Montebello WWTW were used to develop, improve and apply the methodology. Tests at Royton and Chorley were used to develop the practical side of conducting tracer studies. The Preston case study was used to improve the diagnostic methodology. It was demonstrated that consent failures as a result of events are usually a result of a number of (linked) factors, in the case of Preston influenced by the tank conguration. The response of a pulse of dye was measured at Preston in vessel outlet throughout the works. The tracer dyeresponse was used to predict the response to a discharge of high ammoniacal leachate liquor and compared to measured data. This type of calibration experiment facilitated the simulation of different discharge event scenarios. The tracer and modelling techniques were incorporated in a general diagnostic methodology, which caters for a phased approach in diagnostic studies. A series of diagnostic tables take the user through cause - effect hypotheses and possible measurement techniques to use in the diagnostic investigation. Although the diagnostic methodology proved to be a versatile asset optimisation tool, which required considerable less effort than deterministic models, implementation in United Utilities' AMP3 Capital Investment Programme was problematic. The size of the programme and lack of resources forced the company to implement standard rather than tailor-made solutions. However, the diagnostic methodology can easily be applied elsewhere in the wastewater industry.

Pharmaceuticals have been detected in natural waters for more than forty years, but with improvements in sample preparation procedures and analytical instrumentation, the number of scientific publications on the issue has increased significantly. Even though the concentration of pharmaceutical residues in surface and drinking water is not critical for human health according to the present level of knowledge, the consequences for the environment are not clear. Wastewater treatment plants (WWTPs) have been identified as the primary route of pharmaceuticals to the environment, with households as the major source point for most of the over-the-counter and prescription drugs. In this thesis, the first aim was to study the occurrence, fate and removal of 43 pharmaceuticals during conventional wastewater treatment. The target compounds were selected on the basis of their high consumption in Spain or/and frequently reported detection in wastewaters and the possibility to be analyzed under the same experimental conditions. They belong to different therapeutic classes, i.e. nonsteroidal anti-inflammatory agents and analgesics, lipid modifying agents, psycholeptic and antiepileptic drugs, beta-blocking agents, beta-2-adrenoreceptor agonists, H2-receptor antagonists, antibiotics, angiotensin converting enzyme agents, diuretics and antidiabetic drugs. A wide variation in removal efficiencies was observed even for individual compounds, and across therapeutic classes and treatment processes, without clear conclusion on the removal of any particular compound. According to mass balance calculations and estimated partition coefficients, the loss of the selected pharmaceuticals during biological wastewater treatment can be fully attributed to biodegradation/biotransformation. None of the studied compounds was entirely biodegraded and/or transformed during biological wastewater treatment, but the measured concentrations were below the levels of concern according to available toxicity data. Conventional WWTPs cannot be expected to be the only mechanism for controlling the entry of pharmaceuticals into the environment because they were neither designed nor can provide their complete removal. Therefore, the challenge is to look for solutions that would be the most economical and effective means of preventing further pollution of natural waters by pharmaceuticals. More appropriate management of sewage waters before they enter treatment plants as well as a stricter control of effluent discharges, along with an in-depth investigation on the development of new designs and strategies for the improvement of existing wastewater treatments should be considered. In light of this, as the second objective of this thesis, alternative approaches for the removal of the antiepileptic carbamazepine (CBZ) were studied in aqueous media in two laboratory scale experiments: a) biodegradation using white rot fungus T. versicolor in an air-pulsed fluidized bioreactor operated in batch and continuous modes, and b) advanced oxidation using TiO2-heterogeneous photocatalysis under simulated solar and UV-A irradiation, and under the combined use of ultrasound and UV-A irradiation (sonophotocatalysis). We selected CBZ as a representative example of compounds that are found to be refractory to biological treatment and ubiquitous in various environmental matrices. Both, the fungal and UVA-driven TiO2-photocatalytic treatments, very different in their nature, have been shown to be very effective in degrading carbamazepine in aqueous media. The fungal treatment resulted in average removals of 54 and 96% in batch and continuous reactor, respectively. Acute toxicity test using the bioluminescent marine bacterium Vibrio fischeri showed a decrease in toxicity during the treatment in both types of bioreactor. In the other study, initial CBZ concentrations were reduced for 95% during 120 min of the UV-driven photocatalytic experiment and sonophotocatalysis, while only 10 % of CBZ was photodegraded during under solar irradiation. A slight increase in toxicity in Daphnia magna acute toxicity testing was observed over the time-course of the photocatalytic experiments, which can be associated with the formation of transformation products of CBZ. Ultraperformance liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometry was used for a tentative identification of the transformation products of CBZ formed during the performed experiments. Most of the tentatively identified intermediates exhibited only slight modifications of the CBZ molecular structure. The fungal as well as the photocatalytic processes yielded oxygenated transformation products. In the biological treatment using T. versicolor, transformation products were formed by enzymatic epoxidation and hydroxylation of seven-membered heterocyclic ring of the carbamazepine molecule. During the photocatalytic experiments, CBZ-related transformation products emerged from hydroxylation and further oxidation of different parts of the molecule of carbamazepine. The generated transformation products appeared to be more persistent than their parent compound, as they were present, although at low concentration, until the end of the experiments. The results of the thesis contribute to a better understanding of a) the magnitude of the selected pharmaceuticals that reach the environment through the wastewater and sludge discharge, b) the efficiency of typical conventional wastewater treatment plants regarding the removal of these compounds from raw wastewater, and c) possible developments of alternative technologies for their enhanced elimination.
Desde hace más de cuarenta años se ha detectado la presencia de fármacos en el ciclo de aguas, sobre todo debido a los avances en la química analítica que han permitido el desarrollo de nuevas metodologías analíticas para la determinación de estos compuestos de modo fiable y a bajas concentraciones. Las estaciones depuradoras de aguas residuales (EDARs) han sido identificadas como la ruta principal de entrada de fármacos de origen humano en el medioambiente. Por tanto, el principal objetivo de esta tesis ha sido el estudio de la presencia, destino y eliminación de 43 fármacos seleccionados, durante el tratamiento convencional realizado en las EDARs. Los compuestos estudiados fueron seleccionados en base a los índices de consumo en España, a la frecuencia de detección en aguas residuales y además en base a la posibilidad de ser analizados bajo las mismas condiciones experimentales. Estos compuestos pertenecen a diferentes clases terapéuticas, i.e. antiinflamatorios no esteroideos , los agentes que reducen los lípidos séricos, ansiolíticos y antiepilépticos, los agentes bloqueadores beta-adrenérgicos, agonistas β2 adrenérgico, antagonistas H2 , antibióticos, inhibidores de la enzima convertidora de angiotensina, diuréticos y antidiabéticos. Para el análisis cuantitativo se utilizó la cromatografía de líquidos acoplada a espectrometría de masas en tándem (LC-MS/MS), empleando un sistema híbrido triple quadrupolo/trampa de iones lineal. Como segundo objetivo hemos considerado evaluar tratamientos avanzados alternativos al tratamiento convencional para la eliminación de un fármaco antiepiléptico, la carbamazepina, uno de los compuestos más recalcitrantes al tratamiento biológico convencional. Se procedió a estudiar su degradación en medio acuoso mediante dos procedimientos a escala laboratorio: a) biodegradación utilizando el hongo ligninolitico Trametes Versicolor en un reactor fluidizado por pulsos de aire operando en modo batch y continuo, y b) oxidación avanzada mediante un tratamiento fotocatalitico en presencia de TiO2 bajo irradiación UV-A y solar, y aplicando la radiación UV en combinación con ultrasonidos (sonofotocatálisis). Para la evaluación de los tratamientos alternativos, se identificaron los productos de transformación de la carbamazepina, y se evaluó la toxicidad de las muestras tratadas. Se utilizó la LC-MS/MS con analizador de tipo cuadrupolo-tiempo de vuelo. También se evaluó la toxicidad de las muestras tratadas.

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.

Nanotechnology is an increasing market. Engineered nanoparticles (NPs), materials with at least one dimension between 1 and 100 nm, are produced on a large scale. NPs are vastly used in industrial processes and consumer products and they are most likely discharged into wastewater treatment plants after being used. Activated Sludge is one of the most applied biological wastewater treatment processes for the degradation of organic matter in sewage. Activated sludge produces an excess of sludge that is commonly treated and stabilized by anaerobic digestion. Recent studies have found that NPs accumulate in the activated sludge; thus, there is a potential for the concentrations of NPs to magnify as concentrated waste sludge is fed into the anaerobic digestion process. For this reason, it is important to study the possible toxic effects of NPs on the microorganisms involved in the anaerobic digestion process and the approaches to overcome toxicity if necessary. The present work evaluates the toxic effect of NPs on anaerobic wastewater treatment processes and also presents approaches for toxicity attenuation. The first objective of this dissertation (Chapter III) was to evaluate the toxicity of high concentrations (1, 500 mg L⁻¹) of Ag⁰, Al₂O₃, CeO₂, Cu⁰, CuO, Fe⁰, Fe₂O₃, Mn₂O₃, SiO₂, TiO₂, and ZnO NPs to acetoclastic and hydrogenotrophic methanogens and the effect of a dispersant on the NPs toxicity to methanogens. The findings indicated that only Cu⁰ and ZnO NPs caused severe toxicity to hydrogenotrophic methanogens and Cu⁰, CuO, and ZnO NPs to acetoclastic methanogens. The dispersant did not impact the NPs toxicity. The concentrations of Cu⁰ and ZnO causing 50% of inhibition (IC₅₀) to hydrogenotrophic methanogens were 68 and 250 mg L⁻¹, respectively. Whereas the IC₅₀ values for acetoclastic methanogens were 62, 68, and 179 for Cu⁰, ZnO, and CuO-Cu NPs respectively. These findings indicate that acetoclastic methanogens are more sensitive to NP toxicity compared to hydrogenotrophic methanogens and that Cu⁰ and ZnO NPs are highly toxic to both. Additionally, it was observed that the toxicity of any given metal was highly correlated with its final dissolved concentration in the assay irrespective of whether it was initially added as a NP or chloride salt, indicating that corrosion and dissolution of metals from NPs may have been responsible for the toxicity. The second objective of this dissertation (Chapter IV) was to evaluate the Cu⁰ NP toxicity to anaerobic microorganisms of wastewater treatment processes. Cu⁰ is known to be toxic to methanogens; nonetheless, little is known about its toxic effects on microorganisms of upper trophic levels of anaerobic digestion or other anaerobic process used for nitrogen removal. This specific objective evaluated Cu⁰ NP toxicity to glucose fermentation, syntrophic propionic oxidation, methanogenesis, denitrification and anaerobic ammonium oxidation (anammox). Chapter IV showed that anammox and glucose fermentation were the least and most inhibited processes with inhibition constants (K(i)) values of 0.324 and 0.004 mM of added Cu⁰ NPs, respectively. The Ki values obtained from the residual soluble concentration of the parallel experiments using CuCl₂ indicated that Cu⁰ NP toxicity is most likely caused by the release of soluble ions for each one of the microorganisms tested. The results taken as a whole demonstrate that Cu⁰ NPs are toxic to a variety of anaerobic microorganisms of wastewater treatment processes. The third objective of this document (Chapter V) was to study the role of biogenic sulfide in attenuating Cu⁰ and ZnO NP toxicity to acetoclastic methanogens. Previous literature results and research presented in this dissertation indicated that the release of soluble ions from Cu and ZnO NPs cause toxicity to methanogens. In the past, the application of sulfide to precipitate heavy metals as inert non-soluble sulfides was used to attenuate the toxicity of Cu and Zn salts. Building on this principle, Chapter V evaluated the toxicity of Cu⁰ and ZnO NPs in sulfate-containing (0.4 mM) and sulfate-free conditions. The results show that Cu⁰ and ZnO were 7 and 14x less toxic in sulfate-containing than in sulfate-free assays as indicated by the differences in K(i) values. The K(i) values obtained based on the residual metal concentration of the sulfate-free and sulfate-containing assays were very similar, indicating that the toxicity is well correlated with the release of soluble ions. Overall, this study demonstrated that biogenic sulfide is an effective attenuator of Cu⁰ and ZnO NP toxicity to acetoclastic methanogens. Finally, the last objective (Chapter VI) of this dissertation was to evaluate the effect of iron sulfide (FeS) on the attenuation of Cu⁰ and ZnO toxicity to acetoclastic methanogens. FeS is formed by the reaction of iron(II) and sulfide. This reaction is common in anaerobic sediments where the reduction of iron(III) to iron(II) and sulfate to sulfide occurs. FeS plays a key role controlling the soluble concentrations of heavy metals and thus their toxic effects in aquatic sediments. This study evaluated the application of FeS as an approach to attenuate Cu⁰ and ZnO NP toxicity and their salt analogs to acetoclastic methanogens. Two particle sizes, coarse FeS (FeS-c, 500-1200 µm) and fine FeS (FeS-f, 25-75 µm) were synthesized and used in this study. The results showed 2.5x less FeS-f than FeS-c was required to recover the methanogenic activity to the same extent from the exposure to highly inhibitory concentrations of CuCl₂ and ZnCl₂ (0.2 mM). The results also showed that a molar ratio of FeS-f/Cu⁰, FeS-f/ZnO, FeS-f/Zn Cl₂, and FeS-f/CuCl₂ of 3, 3, 6, and 12 respectively, was necessary to provide a high recovery of methanogenic activity (>75%). The excess of FeS needed to overcome the toxicity indicates that not all the sulfide in FeS was readily available to attenuate the toxicity. Overall, Chapter VI demonstrated that FeS is an effective attenuator of the toxicity of Cu⁰ NP and ZnO NPs and their salt analogs to methanogens, albeit molar excesses of FeS were required.

2014 - 2015
More stringent standards on water quality along with the shortage of vater resources have led to the development of advanced wastewater treatment processes, in order to ensure the respect of discharge limits and the reuse of trated water... [edited by author]
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This master thesis gives an account for various aeration schemes that are utilized in conventional activated sludge treatment process in a wastewater treatment plant. By altering between different aeration schemes, the project aimed at reducing energy consumption along with maintaining the treatment performance at the plant. A series of experiments on the treatment performance over several different aeration schemes thus has been conducted on site at Solviken in Mora, Sweden. The project is basically a case study where no parameters were manually controlled except for the aeration schemes at the plant. Energy consumption reduction is logically relative to the ratio between aeration and non-aeration intervals. Several criteria were tested in regards to the treatment performance, including pH value, organic matters, phosphorus substances and microorganisms. The study has come up with a superior aeration scheme for the plant, as well as indicated processes that can be improved at the plant.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
O presente trabalho avalia a utilização de dois diferentes tipos de POA, Fenton-Zero - processo Fenton utilizando ferro zero valente: Fe0/H2O2 - e UV/H2O2 para o tratamento de efluente de indústria de celulose tratado biologicamente. Os parâmetros observados foram DBO, DQO, COT, cor e ABS280nm (medida de compostos ligninícos). Os experimentos foram conduzidos em batelada, em escala de laboratório e utilizando efluente real de indústria de celulose tratado biologicamente. Para os testes com o processo Fenton Zero foram realizados experimentos de acordo com um planejamento fatorial 2 elevado a 3, investigando a influência das variáveis pH, dosagem de peróxido de hidrogênio e massa de ferro zero valente fornecida por volume de solução. Como fonte de ferro foi utilizada lã de aço comercial nas concentrações de 5,5 g/L, 6,5 g/L e 7,5 g/L. As concentrações iniciais de peróxido de hidrogênio estudadas foram de 456,9 mg/L, 913,7 mg/L e 1370,6 mg/L e os valores de pH variaram entre 5.5, 6.5 e 7.5. Foram obtidas médias de remoção de 57,1 por cento de DQO, 67,2 por cento de DBO, 90,5 por cento de Cor, 83,4 por cento de compostos lignínicos e 54 por cento de COT, além de 9,52 mg/L de DBO final e 60,1 mg/L de DQO final. Já os testes com o sistema UV/H2O2 foram conduzidos com o único objetivo de polimento do efluente para reuso pelo processo. Desta maneira, o pH utilizado foi o natural do efluente (7,5) e três doses de H2O2 foram aplicadas, 4,0 g/L, 5,0 g/L e 6,0 g/L estando estas em excesso.
The present work evaluates the use of two different types of AOP: the Zero-Fenton - process using zero valent iron - and UV/H2O2 for the treatment of pulp mill wastewater biologically treated. The observed parameters were BOD, COD, TOC, color and ABS280nm (measure of lignin compounds). The experiments were conducted in batch, lab scale and with real wastewater from biological treatment of a cellulose plant in Brazil. For the Fenton process, experiments were carried out according to a factorial design 23 investigating the influence of the variables pH, hydrogen peroxide dosage and zero-valent iron mass supplied by solution volume. As iron source, commercial steel wool was used in the concentrations of 5.5 g / L, 6.5 g / L and 7.5 g / L. The concentrations of hydrogen peroxide studied were 456.9 mg / L, 913.7 mg / L and 1370.6 mg / L and pH values ranged from 5.5, 6.5 and 7.5. The average removal rate was 57.1 per cent COD, 67.2 per cent COD, 90.5 per cent Color, 83.4 per cent lignin compounds and 54 per cent TOC. Also 9,52 mg/L of final BOD and 60,1 mg/L of final COD. The trials with the UV/H2O2 system, on the other hand, were conducted with the sole objective of polishing the effluent for reuse in the process. The pH used was the effluent s natural (7.5) and three excess doses of H2O2 were applied.

Although wastewater reuse presents numerous benefits, wastewater-borne pathogens, especially human enteric viruses, may pose risks to human health. Wastewater treatment processes have been shown to remove bacterial pathogens more effectively than they do viral pathogens, and in aquatic environments, levels of traditional faecal indicator bacteria (FIB) do not appear to correlate consistently with levels of human viral pathogens. There is, therefore, a need for novel viral indicators of faecal pollution and novel surrogates of viral pathogens. Potential candidates for this role include enteric bacteriophages (phages), viruses capable of infecting enteric bacteria.

Metal organic frameworks (MOFs) are new class of nanomaterials possessing high surface area, large volume and tuneable pore size. These unique materials are promising candidates for wastewater treatment. In this work, several water stable MOFs, namely HKUST-1, UiO-66, ZIF-67, BioMOF-11, MIL-96 and their derivatives, were synthesized solvo/hydrothermally and used in adsorption and/or catalytic degradation of antibiotics, dyes, and personal care products. It is demonstrated that the materials exhibited high adsorption capacity and good catalytic performance.

2015 - 2016
The research of new eco-friendly technologies that enable the production of energy is nowadays one of the topics of greatest interest to the scientific community. The population has chosen to break free from the use of fossil fuels, and this leads to the study and development of processes for the production of clean energy starting from biomass. However, at the same time, the concern of the industry is also the disposal and treatment of wastewater. Starting from these considerations, it is advisable to develop processes that, under mild conditions, allow to obtain interesting hydrogen or methane yields. This objective could be achieved through the use advanced oxidation processes (AOPs), such as heterogeneous photocatalysis, photo-Fenton like reaction and photoelectrocatalysis. So, an interesting approach is to explore, in parallel to wastewater treatment, the possibility to produce also an energy source such as hydrogen and/or methane from the degradation of organic substance present in wastewater by AOPs. Considering the characteristic of food industries wastewaters, it is interesting to evaluate the performances of advanced oxidation processes for their treatment aimed to the valorization, through the conversion of specific substances (sugars), in order to obtain compounds with high energetic value, but also for removing substances hardly biodegradable (such as food dyes) that could be present in these industry wastewaters. In this PhD thesis it has been studied the performances of the photocatalytic process for the hydrogen production from food industries wastewaters. In particular, starting from synthetic solution containing glucose, it was evaluated the effect of the presence of noble metals on the semiconductor surface and the effect of the photoactive support (TiO2). Subsequently, providing for the application of heterogeneous photocatalysis to industrial level, the study has been directed to the formulation of a noble metal free photocatalyst with good performances in the production of hydrogen and in the degradation of the sugars present in the solutions. The final formulation was represented by LaFeO3 (a perovskite with semiconducting properties) prepared by combustion flame method. To improve the performances under visible light, LaFeO3 was modified with Ru (Ru-LaFeO3), whose cost is much lower than those of Pd, Pt or Au. Always perspective of the application of the process to industrial level, it was developed a structured photocatalyst for solving the problems related to the photocatalyst separation after the treatment. In particular it was studied the efficiency of magnetic Fe2O3 as support for Ru-LaFeO3. It was also investigated the photoelectrocatalytic process for the hydrogen production, considering the general aspects of the process, the advantages and in particular the attention has been focused on the electrodeposition process for the synthesis of Fe2O3 based photoanodes. Finally, the aim has been the application of the photocatalytic process on a real wastewater coming from the washing process of the fruit (especially cherries). It was not underestimated the presence of food dyes in these types of wastewater. For this reason it was evaluated the efficiency of photo-Fenton process in the removal of several food dyes (such as Red Allura and Tartrazine) using LaFeO3 deposited on corundum monoliths. In addition, it has been evaluated the possibility to couple the photocatalytic process (used for the valorization of the wastewater through the production of hydrogen) to the optimized photo-Fenton system to completely remove the not-biodegradable substances still present in the wastewaters recovered after the photocatalytic treatment using Ru-LaFeO3 supported on magnetic Fe2O3 particles. [edited by author]
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In the past decades, hydrodynamic cavitation (HC) process was the subject of study by many researchers worldwide. This phenomenon was widely studied in order to understand the reason of its negative effects on hydraulic machinery such as pumps,turbines, valves, etc. Many efforts were made in order to better understand mechanisms of HC process with the main aim of preventing its generation and trying to avoid severe physical damage such as erosions, vibrations and noises. In recent years, in order to cope with a decrease in available water resources worldwide, an increasing demand of water by population in developing/developed countries and more restrictive environmental legislations on water quality, HC was increasingly used as a novel energy-efficient technique in the field of wastewaters treatment. The main purpose of this thesis is to investigate on the effectiveness of a modified swirling-jet device called Ecowirl reactor, patented by Econovation GmbH, Germany and produced and commercialized by Officine Parisi s.r.l., Italy. Experimental studies were carried out in order to evaluate the effects of different operative conditions and parameters such as reactor geometry, flow rate, flow velocity, pressure, medium pH, medium concentration and medium temperature on (i) the degradation of a toxic and carcinogenic pollutant dye (Rhodamine B, RhB) in waste dye aqueous solutions and on (ii) the improvement of activated sludge solubilisation and aerobic sludge biodegradability in the field of biological wastewater treatments. In order to better understand the fluid dynamics into Ecowirl reactor, it was modelled. The model based on previous experimental data was implemented in a Computational Fluid Dynamics software (ANSYS, 16.2).

In the past decades, hydrodynamic cavitation (HC) process was the subject of study by many researchers worldwide. This phenomenon was widely studied in order to understand the reason of its negative effects on hydraulic machinery such as pumps,turbines, valves, etc. Many efforts were made in order to better understand mechanisms of HC process with the main aim of preventing its generation and trying to avoid severe physical damage such as erosions, vibrations and noises. In recent years, in order to cope with a decrease in available water resources worldwide, an increasing demand of water by population in developing/developed countries and more restrictive environmental legislations on water quality, HC was increasingly used as a novel energy-efficient technique in the field of wastewaters treatment. The main purpose of this thesis is to investigate on the effectiveness of a modified swirling-jet device called Ecowirl reactor, patented by Econovation GmbH, Germany and produced and commercialized by Officine Parisi s.r.l., Italy. Experimental studies were carried out in order to evaluate the effects of different operative conditions and parameters such as reactor geometry, flow rate, flow velocity, pressure, medium pH, medium concentration and medium temperature on (i) the degradation of a toxic and carcinogenic pollutant dye (Rhodamine B, RhB) in waste dye aqueous solutions and on (ii) the improvement of activated sludge solubilisation and aerobic sludge biodegradability in the field of biological wastewater treatments. In order to better understand the fluid dynamics into Ecowirl reactor, it was modelled. The model based on previous experimental data was implemented in a Computational Fluid Dynamics software (ANSYS, 16.2).

Conventional end-of-pipe solutions for wastewater treatment have been criticized from a sustainable view-point, in particular regarding recycling of nutrients. The integration of hydroponic cultivation into a wastewater treatment system has been proposed as an ecological alternative, where nutrients can be removed from the wastewater through plant uptake; however, cultivation of plants in a temperate climate, such as Sweden, implies that additional energy is needed during the colder and darker period. Thus, treatment capacity, additional energy usage and potential value of products are important aspects considering the applicability of hydroponic wastewater treatment in Sweden.

To enable the investigation of hydroponic wastewater treatment, a pilot plant was constructed in a greenhouse located at Överjärva gård, Solna, Sweden. The pilot plant consisted of several steps, including conventional biological processes, hydroponics, algal treatment and sand filters. The system treated around 0.56-0.85 m3 domestic wastewater from the Överjärva gård area per day. The experimental protocol, performed in an average of twice per week over a period of three years, included analysis and measurements of water quality and physical parameters. In addition, two studies were performed when daily samples were analysed during a period of two-three weeks. Furthermore, the removal of pathogens in the system, and the microbial composition in the first hydroponic tank were investigated.

Inflow concentrations were in an average of around 475 mg COD/L, 100 mg Tot-N/L and 12 mg Tot-P/L. The results show that 85-90% of COD was removed in the system. Complete nitrification was achieved in the hydroponic tanks. Denitrification, by means of pre-denitrification, occurred in the first anoxic tank. With a recycle ratio of 2.26, the achieved nitrogen removal in the system was around 72%. Approximately 4% of the removed amount of nitrogen was credited to plant uptake during the active growth period. Phosphorus was removed by adsorption in the anoxic tank and sand filters, natural chemical precipitation in the algal step induced by the high pH, and assimilation in plants, bacteria and algae. The main removal occurred in the algal step. In total, 47% of the amount of phosphorus was removed. Significant recycling of nitrogen and phosphorus through harvested biomass has not been shown. The indicators analysed for pathogen removal showed an achieved effluent quality comparable to, or better than, for conventional secondary treatment. The microbial composition was comparable to other nitrifying biological systems. The most abundant phyla were Betaproteobacteria and Planctomycetes.

In Sweden, a hydroponic system is restricted to greenhouse applications, and the necessary amount of additional energy is related to geographic location. In conclusion, hydroponic systems are not recommended too far north, unless products are identified that will justify the increased energy usage. The potential for hydroponic treatment systems in Sweden lies in small decentralized systems where the greenness of the system and the possible products are considered as advantages for the users.

The Integrated Film Activated Sludge Process (IFAS) was developed to reduce the cost of additional facilities required to complete year round nitrification in the design of new or retrofit wastewater treatment plants. The purpose of this project was to develop a computer-based mechanistic model, called IFAS, which can be used as a tool by scientists and engineers to optimize their designs and to troubleshoot a full-scale treatment plant. The program also can be employed to assist researchers conducting their studies of IFAS wastewater treatment processes. IFAS enables the steady-state simulation of nitrification-denitrification processes as well as carbonaceous removal in systems utilizing integrated media, but this current version supports only sponge type media. The IFAS program was developed by incorporating empirical equations for integrated biofilm carbonaceous uptake and nitrification developed by Sen and Randall (1995) into the general activated sludge model, developed by the International Association on Water Quality (IAWQ, previously known as IAWRC), plus the biological phosphorus removal model of Wentzel et al (1989). The calibration and evaluation of the IFAS model was performed using existing data from both an IFAS system and a conventional activated sludge bench-scale plant operated over a wide range of Aerobic Mean Cell Residence Times (Aerobic MCRT's). The model developed provides a good fit and a reasonable prediction of the experimental data for both the IFAS and the conventional pilot-scale systems. The phosphorus removal component of the model has not yet been calibrated because of insufficient data and the lack of adequately defined parameters.
Master of Science

In recent years, endocrine disruption of corticosteroid signaling pathways in wildlife and humans by environmental chemicals have attracted increasing attention. The integrated potential of chemicals in the aquatic environment that disrupt corticosteroid actions have been evaluated using in vitro glucocorticoid receptor (GR) mediated bioassays. Exogenous natural and synthetic corticosteroids (CSs), which are widely used in human and animal therapeutic applications, were demonstrated to be the most important GR agonists, that can potentially cause adverse effects, especially on aquatic organisms. To date, only a few studies have investigated the occurrence and behavior of GR agonists in the aquatic environment and their removal in conventional wastewater treatment plants. Furthermore, there are hardly any data reported on the removal of GR agonists by advanced water and wastewater treatment, especially those synthetic CSs with high potency. To further understand the fate of GR agonists in water and wastewater treatment processes, a sensitive and robust LC-MS/MS method was successfully developed for analyzing a wide range of GR agonists in various environmental waters. The occurrence of GR agonists in surface water and groundwater was monitored along the Lower Santa Cruz River (SCR). Several GR agonists were detected, and a trend of degradation was observed downstream the two WWTP outfalls for both surface water and groundwater. The fate of GR agonists in a local wastewater treatment plant (WWTP) was investigated, and up to 14 GR agonists were detected at different stages. Highly potent synthetic CSs, including clobetasol propionate (CBP), fluticasone propionate (FTP), fluocinolone acetonide (FCA), and triamcinolone acetonide (TCA), were poorly removed in WWTP. Negative removal of some CSs was observed in primary treatment, which may due to the deconjugation of CS conjugates. Removal of GR agonists in secondary effluent during various advanced water treatment processes, including UV, ozonation, MF, RO and chlorination, were studied. UV and RO appeared to be the most efficient treatment process for the attenuation of GR agonists, followed by ozone, while chlorination had little effects on GR agonists in water. Bench-scale experiments were then carried out to investigate the removal of GR agonists by ultraviolet based advanced oxidation processes (UV/AOPs), and powder activated carbon (PAC). UV/chlorine and UV/H2O2 were demonstrated to be effective in removal GR agonists in wastewater, and UV photolysis would be the predominant mechanism in UV/AOP processes. Four types of PACs were tested for removing GR agonists in wastewater effluent, and Cabot HDB carbon was suggested, while Calgon PWA carbon was not recommended due to its low removal efficiency.

Un aspect clé permettant de surmonter les défis énergétiques et environnementaux est d'améliorer l'efficacité des nouveaux procédés. La plupart des produits chimiques majeurs se faisant par des procédés catalytiques, une meilleure compréhension des cinétiques de réaction est nécessaire. Dans le domaine du traitement des eaux usées, l'ozonation catalytique est en un exemple typique. Dans cette thèse, des microréacteurs catalytiques sont utilisés en tant qu’outils analytiques innovants afin de déterminer la cinétique de l'ozonation catalytique. Ceux-ci ont pu être élaborés à l'aide de procédés plasma en déposant et en activant un catalyseur à base d’oxyde de fer et de cobalt. L’efficacité de ces catalyseurs a été mesurée en utilisant de l'acide pyruvique en tant que polluant modèle. Pour Fe2O3, les mesures HPLC ont montré l'inactivité de celui-ci par rapport à Co3O4 (20%). Cet effet a été doublé après post-traitement par un plasma d'Ar, démontrant ainsi le rôle du plasma. Une simulation numérique portant sur les réactions à la surface du catalyseur a été réalisée en utilisant le logiciel Comsol Multiphysics. Le modèle utilisé s’est partiellement approché des données expérimentales en raison du manque de données concernant les constantes de réactions des espèces intermédiaires. Ces constantes cinétiques pourront être déterminées grâce à l'utilisation de la technique de spectroscopie Raman Anti-Stokes Cohérente (technique CARS) en tant qu’outil d'analyse en temps réel. En perspectives, l’utilisation de cette dernière conduira à l’élaboration d’un outil efficace qui pourrait prédire la pertinence et les futures stratégies d'amélioration sur des réactions chimiques catalysées
A key aspect in overcoming the energy and environmental challenges is to improve the efficiency of existing and new processes. Nowadays, almost all major chemicals are produced by catalytic processes. However, a better understanding of the reaction pathways and kinetics is needed. In the field of wastewater treatment, catalytic ozonation is a typical example of this problem. In this study, catalytic microreactors were used as innovative analytical tools for the determination of kinetics of catalytic ozonation and were elaborated by using low pressure plasma processes for the deposition and activation of iron and oxide-based catalysts on polymer-based materials. Catalytic ozonation with pyruvic acid as a refractory probe compound was performed with both catalysts. HPLC measurements showed the inactivity of the iron oxide layer compared to the cobalt oxide one which led to 20 % of degradation. The effect was doubled when the latter was post-treated by an argon plasma, demonstrating the role and importance of the plasma post-treatment step. A numerical study dealing with the reactions taking place on the surface of the catalyst was carried out using the Comsol Multiphysics software and showed that the model partially fitted the experimental data due to the lack of information. However, access to the reactions rate constants of the intermediate species generated during the catalytic ozonation step could be achieved through the use of the Coherent Anti-Stokes Raman Spectroscopy technique and would lead to an efficient tool to predict the relevance and the direction of future improvement strategies regarding catalyzed chemical reactions

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10).

Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5–7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2–3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.

Today billions of people live without access to basic sanitation facilities, and thousands die every week due to diseases caused by fecal contamination associated with improper sanitation. It has thus become crucial for decision makers to have access to relevant and sufficient data to implement appropriate solutions to these problems. The Global Water Pathogen Project http://www.waterpathogens.org/ is dedicated to providing an up-to-date source of data on pathogen reduction associated with different sanitation technologies that are important if the world is to achieve the Sustainable Development Goals (SDGs) related to health and sanitation provision. In this research, a subset of the Global Water Pathogen Project (GWPP) data is used to access the reduction of bacteria and viruses across different mechanical and natural sanitation technologies. The order of expected removal for bacteria during wastewater treatment was reported as highest for a membrane bioreactor (4.4 log10), waste stabilization pond (2.3 log10), conventional activated sludge (1.43 log10), anaerobic anoxic oxic activated sludge (1.9 log10), trickling filter (1.16 log10), and upflow anaerobic sludge blanket reactor (1.2 log10). Furthermore, the order of expected removal for viruses was reported as highest for a membrane bioreactor (3.3 log10), conventional activated sludge (1.84 log10), anaerobic anoxic oxic activated sludge (1.67 log10), waste stabilization pond (1 log10), upflow anaerobic sludge blanket reactor (0.3 log10) and trickling filter (0.29 log10). It was found that hydraulic retention time (HRT) had a statistically significant relation to the reduction of bacteria in an anaerobic, anoxic oxic treatment system. Similarly, a significant relation was found between the number of waste stabilization ponds in series and the expected reduction of bacteria. HRT was also found to be a significant factor in virus reduction in waste stabilization ponds. Additionally, it was observed that waste stabilization ponds, trickling filters, and UASB reactors could obtain a greater reduction in bacteria (5-7 log10) when combined with additional treatment (e.g., chemical disinfection or use of maturation ponds). Also, mechanized systems, such as activated sludge systems and membrane bioreactors, obtained a greater reduction (2-3 log10) of viruses when compared to a natural system. It was concluded that the selection of the best suitable technology for pathogen reduction depends on environmental, design, and operational factors as well as considering the performance of specific wastewater treatment systems individually as well as when combined with other treatment technologies that may provide added removal of microbial constituents.

This thesis presented the dewatering performance improvement of anaerobically digested sludge with novel application and assessment of conditioning aids. The effectiveness of sludge conditioning was evaluated by batch experiments using a series of 250-mL jar test beakers. The optimal dosage was found at 15–20 g/kg chitosan with enhanced dewaterability and rheological behaviour. The dual-chemical conditioning results indicate a higher rate of water removal at the expense of dry solids content compared to single conditioning.

The increasing cost of effluent treatment in the wool scouring industry is rapidly becoming a determining factor in the viability of existing scouring operations and new installations alike. This thesis details the development of an integrated effluent treatment process capable of treating the worst polluted effluent from a wool scour "heavy flow-down", to the point where it can either be economically discharged to local trade waste sewer, or directly discharged to river or ocean outfall with minimal environmental impact. The existing proprietary chemical flocculation process, Sirolan CF™, was improved by the addition of a bio-flocculation stage and turbidity monitoring and control, and the product from this process fed to an aerobic biological treatment system based upon the traditional activated sludge process. The biological treatment process was found to remove up to 98% of the BOD5 loading from the pre-treated liquor with a hydraulic residence time of at least 50 hours being required in the aerobic digestion vessels. A residual biorefractory COD of approximately 3,600mg/L was identified which could not be removed by biological treatment. When operating continuously, the biological process was observed to metabolically neutralise the pH 3.0 - 4.5 feed from the chemical flocculation system to pH > 7.0 without the need for supplemental addition of neutralising agents such as sodium hydroxide. This in itself provides a significant economic incentive for implementation of the process. Kinetic analysis of the biological process carried out under controlled laboratory conditions using a Bioflo 3000 continuous fermentor showed that the bio-chemical process followed substrate inhibition kinetics. An appropriate kinetic model was identified to represent the behaviour of the substrate degradation system, and modified by inclusion of a pseudo toxic concentration to account for the effect of pH inhibition upon the biological growth rate. The process was verified both at pilot plant scale and at demonstration plant scale at an operational wool scour. The demonstration plant was of sufficient size to handle the full heavy effluent flow-down from a small wool scour. At the time of publishing three full-scale effluent treatment systems based on this research had been sold to both domestic and international clients of ADM Group Ltd. who funded the research.

Abstract Treatment wetlands (TW) constructed on natural wetlands potentially perform efficient purification of wastewater, but the longevity of TWs at northern latitudes is not well known. This thesis examined processes affecting nutrient and suspended solids (SS) retention in TWs during their lifetime. In total, 15 TWs were studied using water and peat quality and gas flux data for different TW life lengths, the longest period being 18 years. The TWs commonly retained nutrients and suspended solids efficiently, even after 18 years of wastewater loading. For nitrogen (N) removal, sedimentation, nitrification-denitrification and plant uptake were efficient processes in the wetlands studied. However, emissions of nitrous oxide (N2O) from TWs are not a major contributor to climate change due to the small total surface area of TWs. The significance of anaerobic ammonium oxidation (anammox) and other newly discovered nitrogen processes in TWs remains to be clarified. Phosphorus (P) adsorption capacity in TWs remained efficient over a 12-year study period, the process being continuous when surfaces for adsorption were available or freed up through alternating absorption/desorption/adsorption. Phosphorus accumulation by peat accretion was low, but has not been well assessed in northern TWs receiving nutrient-rich waters. Iron (Fe) and aluminium (Al) in peat extraction runoff and purified wastewater from sewage treatment plants were of great importance for precipitation of P in TWs. Filtration and sedimentation of organic humic substances with Fe- or Al-bound P were other probable P retention pathways. In peat extraction runoff, Fe was more significant than Al for P retention, but Fe-bound P is susceptible to desorption in anaerobic environments, whereas Al-bound P is more strongly retained. Suspended solids were generally retained well, although there was great variation in percentage retention in individual TWs in different years and different seasons. Changes in discharge affected SS transportation and retention. SS were retained by sedimentation, the rate of which was affected by particle size. It is plausible that smaller particles from old peat extraction areas where the extracted peat has a high humification degree erode more easily than poorly humified particles in surface peat. Weakened SS retention may also have been caused by development of preferential flow areas (PFA) in TWs, changes in sediment delivery characteristics and sampling involving too few samples to show SS transportation sufficiently accurately for estimating SS retention. Thus TWs are potentially ideal for purification of wastewater and can have high purification efficiency even after long-term use in northern regions. They are also more widely applicable as long as their limitations are understood
Tiivistelmä Kosteikkopuhdistamot, jotka on rakennettu luonnonkosteikoille, voivat tehokkaasti vähentää erilaisten maankäyttömuotojen ja pistekuormituslähteiden vesistökuormitusta. Niiden käyttöikää pohjoisilla alueilla ei kuitenkaan tunneta hyvin. Tässä väitöskirjassa tarkastellaan kosteikkopuhdistamoissa tapahtuvia biologisia, kemiallisia ja fysikaalisia prosesseja, joilla on vaikutusta ravinteiden ja kiintoaineen pidättymiseen. Yhteensä 15 eri-ikäisen kosteikkopuhdistamon toimintaa tutkittiin veden ja turpeen laadun sekä kasvihuonekaasumittausten avulla. Näistä vanhinta kosteikkoa oli tutkimusta tehdessä käytetty 18 vuotta turvetuotannon valumavesien puhdistukseen. Tyypillisesti kosteikkopuhdistamot pidättivät ravinteita ja kiintoaineita tehokkaasti jopa 18 vuoden käytön jälkeen. Typenpoistossa sedimentaatio, nitrifikaatio-denitrifikaatio ja kasvien ravinteidenotto olivat tutkituilla kosteikoilla tehokkaita prosesseja. Kosteikkopuhdistamoiden typpioksiduulipäästöt (N2O) ilmaan eivät kuitenkaan ole merkittäviä ilmastonmuutoksen aiheuttajia, koska tällaisten kosteikkopuhdistamoiden kokonaispinta-ala on pieni. Anammox- (anaerobic ammonium oxidation) ja muiden viimeaikoina muissa tutkimuksissa havaittujen typpiprosessien merkitys kosteikoilla tulisi vielä selvittää. Fosforin adsorptiokyky kosteikkopuhdistamoilla pysyi tehokkaana 12 vuoden tutkimusjaksolla, koska niissä adsorptiopintoja oli joko vapaana tai niitä vapautui absorptio- ja desorptioprosessien seurauksena. Kosteikkopuhdistamolla fosforin kertyminen turpeen muodostuksessa arvioitiin vähäiseksi, tosin kertymistä ei ole tarkkaan määritetty pohjoisilla kosteikkopuhdistamoilla, joihin tulee ravinteikasta vettä. Turvetuotannon valumavesissä ja jätevedenpuhdistamoilta tulleissa vesissä orgaanisten humusaineiden rautaan ja alumiiniin sitoutuneen fosforin suodattuminen ja sedimentoituminen olivat muita todennäköisiä fosforin pidättymismekanismeja kosteikoilla. Turvetuotannon valumavesissä rauta oli alumiinia merkittävämpi tekijä fosforin pidättymisessä. Rautaan sitoutunut fosfori on kuitenkin altis desorptiolle hapettomissa olosuhteissa, kun taas alumiiniin sitoutunut fosfori pidättyy pysyvämmin. Kiintoaines pidättyi kosteikkopuhdistamoissa yleensä hyvin, vaikka pidättyneen aineen osuudessa kokonaiskuormituksesta oli suurta vaihtelua yksittäisissä kosteikkopuhdistamoissa eri vuosina ja eri vuodenaikoina. Muutokset virtaamissa vaikuttivat kiintoaineksen kulkeutumiseen ja pidättymiseen. Kiintoaines pidättyy sedimentaatiossa, jonka suuruuteen vaikuttaa kiintoaineen partikkelikoko. On todennäköistä, että vanhojen turvetuotantoalueiden korkean humusasteen pienikokoiset turvepartikkelit erodoituvat helpommin kuin pintaturpeen vähemmän hajonneet partikkelit. Heikentynyt kiintoaineen pidättyminen saattaa aiheutua myös kosteikkopuhdistamoiden oikovirtauksien kehittymisestä, muutoksista sedimentin kulkeutumistavoissa ja liian harvoista näytteenotoista, jolloin ei pystytä riittävän tarkasti arvioimaan kiintoaineksen pidättymistä. Kosteikkopuhdistamot voivat olla ideaalisia jätevesien puhdistamiseen ja ovat osoittaneet hyvää puhdistustehokkuutta myös pitkäaikaisessa käytössä pohjoisissa olosuhteissa. Siten ne ovat laajasti sovellettavissa, kunhan niiden käyttömahdollisuuksien rajoitteet on otettu huomioon

Phosphorus (P) is one of the most important elements exists in wastewater in soluble forms. Several methods have been using for P recovery in wastewater treatment plants, but this study tried to investigate on the most important drivers and the processes of biological phosphorus removal (EBPR) and chemical phosphorus removal that are the major technics of P recovery globally. It has been considered that EBPR is a high recovery method (normally greater than 90%) which could be implemented in different regimes with the integration feasibility of different methods, while chemical precipitation is a flexible technique that could be dosed in various section of a treatment unit. The performance and drivers of three metal-based salts such as Iron (Fe), Aluminum (Al), and Calcium (Ca) also investigated during chemical precipitation. The crystallization process is also investigated as a subcategory model of chemical P removal method. It has been considered that the alkaline pH of 9-9.5, mixing intensity, and the addition of isomorphic seed materials are the most important factors in the crystallization process.

This PhD project focused mainly the OSA technology, developed at Trieste University but also consider the AnMBR technology that was developed at the Barcelona University,working with a laboratory scale AnMBR, fed with winery synthetic wastewater at low temperatures as novelty (from the start-up at 35°C, later at 25°C and finally at 15°C),and evaluating its removal efficiency and methanogenic activity. The COD removal was of 80% and 71% at 25°and 15°C, respectively and without suspended solids in the effluent.The main study on OSA technology was performed at the Trieste University, in teamwork with a wastewater treatment company (CAFC Spa, Udine). The novelty of this research is the use of a real wastewater feed in an OSA pilot plant.The research concerned a first period (1st and 2nd year) with the project and construction of an automated OSA pilot plant, located close to the CAFC wastewater treatment plant (12,000 PE) of Terenzano, a village about 70 km from Trieste, and fed with the same wastewater of the real plant. In the last part of the study (3rd year), the OSA pilot plant was studied (and modelled), by applying respirometric techniques, evaluating the quality of the effluent, the sludge reduction feasibility and the effect on biomass activity.

Water treatment plant (WTP) residual discharge is considered a pollutant and requires treatment to prevent negative impacts when released to the environment. As regulatory requirement becomes increasingly strict, WTPs are required to find suitable methods for the treatment of sludge residuals. Wastewater treatment plants(WWTP) provide existing treatment methods to remove contaminants from WTP residuals. A case study on the Carbondale Water Treatment Plant (CWTP) and receiving Carbondale Southeast Waste Water Treatment Plant (SEWWTP) provided an opportunity to quantify potential negative impacts for the discharge of residual alum sludge to a biologic sludge digestion plant. The first part of the study focused on quantifying changes to the SEWWTP loading conditions from the addition of metal salt coagulant water treatment residuals discharged by the CWTP. Historic sludge quantities and treatment methodologies for both the CWTP and SEWWTP were used to predict loading conditions and residual concentrations at the SEWWTP. Ammonia, BOD, pH, and TSS concentrations from the CWTP were not identified to significantly impact the existing concentrations at the SEWWTP. Metals concentrations from the CWTP were also found to fall within WWTP regulatory quantities. The second part of the study evaluated potential impacts to beneficial bacteria populations in the SEWWTP oxidation ditch from the receipt of CWTP alum residuals. Studies of residual alum sludge impacts to beneficial bacterial populations are rare, and often do not translate from one treatment plants processes to the next. The SEWWTP employs a multi-ring oxidation ditch with an anoxic outer ring and aerobic middle and inner rings. Biologic Activity Reaction Tests (BART) were used to isolate beneficial bacteria species typically present in oxidation ditches including heterotrophic aerobic bacteria, denitrifying bacteria, and nitrifying bacteria. Heterotrophic aerobic bacteria and denitrifying bacteria are the predominant beneficial bacteria species in the outer ring, while nitrifying bacteria and heterotrophic aerobic bacteria dominate the aerobic inner rings. Heterotrophic aerobic bacteria and denitrifying bacteria populations identified in the outer ring of the oxidation ditch did not demonstrate any population impacts from the receipt of residual alum sludge. In addition, nitrifying bacteria populations and heterotrophic aerobic bacteria population demonstrated no impacts from the introduction of CWTP residual alum waste to the aerobic inner ring of the oxidation ditch. Overall, the study demonstrated the treatment of residual alum sludge from a WTP is possible through the existing biological processes at a WWTP.

Wood is a material with an enormous number of applications. For decades, the development of wastewater treatment technologies tailored for the wood sector has focused on those industries that have water as an integral part of the industrial production, such as paper and pulp. However, there is a large and potentially growing sector that has been neglected, which is formed by industries in which water is not part of their production line, as for example, the wood floor and furniture industries (named wood-based dry industries). These industries still produces relatively low volumes of highly polluted wastewaters, with COD up to 30,000 mg/L, due to cleaning/washing procedure (named cleaning wastewaters). These cleaning wastewaters are often sent to the municipal wastewater treatment plant after dilution with potable water. Once there, recalcitrant pollutants are diluted and discharged into recipient water bodies or trapped in the municipal wastewater sludge. Another type of contaminated water these “dry industries” often generate in high volumes, and which is usually discharged with no previous treatment, is storm-water containing contaminants that have leached from large wood storage areas. The overall aim of this thesis was to increase the level of knowledge and competence and to present on-site wastewater treatment options for wood-based dry industries using the wood floor industry as a case-study, with a focus on combined treatment methods and solutions applicable to both the cleaning wastewater and storm-water. Among the treatment technologies investigated, electrocoagulation was studied both as a standalone treatment and combined with sorption using activated carbon. The combined treatment achieved a COD reduction of approximately 70%. Some advanced oxidation processes (AOP) were also studied: a COD reduction of approximately 70% was achieved by photo-Fenton, but the most successful AOP was ozone combined with UV light, were a COD reduction around 90% was achieved, with additional improvement in the biodegradability of the treated effluent. Ozone also proved to be effective in degrading organic compounds (approximately 70% COD reduction) and enhanced the biodegradability of the storm-water runoff from wood storage areas. The results have shown that the application of ozone can be considered an option for treatment of cleaning wastewaters and possibly for storm-water biodegradation enhancement.
Trä är ett material med ett stort antal möjliga användningsområden. Inom träindustrin har utvecklingen av vattenbehandlingsmetoder varit inriktat på de branscher som har vatten som en del av produktionen, såsom papper- och massaindustrin. Men det finns en stor och potentiellt växande sektor inom träindustrin som har försummats, den utgörs av industrier som inte har vatten som en del av produktionen, t.ex. trägolv och trämöbel industrier. Trots detta så producerar dessa industrier fortfarande relativt kraftigt förorenade avloppsvatten med t.ex. COD-värden upp till 30000 mg/l men i relativt låga volymer. Dessa avloppsvatten uppkommer vid rengöring av maskiner och städning av lokaler, varefter de oftast efter utspädning med dricksvatten skickas till det kommunala reningsverket. Väl där späds det förorenade vattnet vidare ut med annat inkommande vatten men passerar dock till stor del obehandlat och släpps ut i mottagande vattendrag eller så fastnar föroreningarna i avloppsslamet. Dagvatten är en annan typ av förorenat vatten från dessa "torra industrier" som ofta genereras i stora volymer och innehåller föroreningar som lakats från de trämaterial som förvaras i de stora upplag som ofta förekommer vid denna typ av industrier. Det övergripande syftet med avhandlingen var att öka kunskapen och kompetensen för att kunna miljömässigt riktigt och ekonomiskt billigt behandla industriavloppsvatten lokalt på plats inom trävaruindustrin, genom att använda en trä-golvsindustri som fallstudie. Fokus lades på kombinerade behandlingsmetoder och lösningar som skulle kunna vara lämpliga både för industriavloppsvatten och dagvatten. Ett antal behandlingstekniker har undersökts; elektrokoagulering studerades både som en fristående behandling och i kombination med aktivt kol. Den kombinerade behandlingen gav en COD-reduktion på ungefär 70 %. Flera avancerade oxidationsprocesser (AOP) studerades också, och en COD-reduktion på cirka 70% uppnåddes med en kombination av UV-ljus och Fenton behandling. Den mest framgångsrika behandlingen var ozon i kombination med UV-ljus där en COD-reduktion runt 90 % uppnåddes varvid en avsevärd förbättring av den biologisk nedbrytbarhet på det behandlade avloppsvattenet erhölls. Ozon visade sig också vara effektivt för nedbrytning av organiska föreningar (ca 70% COD reduktion) och förbättrade den biologiska nedbrytbarheten av föroreningarna i dagvattnet från den studerade industrin. Resultaten har visat att ozon kan anses vara ett lämpligt alternativ för att behandla industriavloppsvatten inom trävarusektorn och möjligen för att öka den biologiska nedbrytbarheten av dagvattnet från dessa industrier
Integrated Approach for Handling of Industrial Wastewater and Stormwater
Triple Helix Collaboration on Industrial Water Conservation in Småland and the Islands

This research effort involved the application of indirect- and direct-contact, freeze-thaw conditioning techniques for improving the dewatering characteristics of both wastewater and water treatment sludges. Sludges tested included waste activated sludge, primary sewage sludge, waste activated/primary sewage sludge mixtures and alum sludge. The direct-freeze methods examined were the use of a secondary refrigerant (butane) evaporated in the sludge and the use of gas hydrate or clathrate formation by addition of Freon 12 under appropriate temperature and pressure conditions. Sludges were also frozen solid using indirect freezing methods, thawed and tested for comparative purposes. Particle size distribution and floc density measurements were used to determine changes in particle characteristics; specific resistance values and dewatered dry solids concentration were used to assess dewatering characteristics. Results of direct- and indirect-contact, freeze-thaw conditioning were compared to the effects of polymer conditioning. The results indicated that direct-freeze methods do not appear technically or economically competitive with currently accepted conditioning methods. The superior results obtained with the indirect-contact, freeze-thaw process when compared to the direct-contact processes suggested that the extent and rate of freezing may greatly influence the particle characteristics of the conditioned sludge, and thus its dewatering characteristics.
Ph. D.

In the 21st Century, water is already a limited and valuable resource, in particular the limited availability of fresh water sources. The projected increase in global population from 6 billion people in 2010 to 9 billion in 2050 will only increase the need for additional water sources to be identified and used. This situation is common in many countries and is frequently exacerbated by drought conditions. Water management planning requires both the efficient use of water sources and, increasingly, the re-use of domestic and industrial wastewaters. A large body of published research spanning several decades is available, and this research study looks specifically at ways of improving the operation of wastewater treatment processes.Process fault diagnosis is a major challenge for the chemical and process industries, and is also important for wastewater treatment processes. Significant economic and environmental losses can be attributed to inappropriate Abnormal Event Management (AEM) in a chemical/processing operation, and this has been the focus of many researchers. Many researchers are now focusing on the application of several fault diagnosis techniques simultaneously in order to improve and overcome the limitations experienced by the individual techniques. This approach requires resolution of the conflicts ascribed to the individual methods, and incurs additional costs and resources when employing more than one technique. The research study presented in this thesis details a new method of using the available techniques. The proposal is to use different techniques in different roles within the diagnostic approach based upon their inherent individual strengths. The techniques that are excellent for the detection of a fault should be employed in the fault detection, and those best applied to diagnosis are used in the diagnosis section of a diagnostic system.Two different techniques are used here, namely a mathematical model and data mining are used for detection and diagnosis respectively. A mathematical model is used which is based upon the principal of analytical redundancy in order to establish the presence of a fault in a process (the fault detection), and data mining is used to produce production rules derived from the historical data for the diagnosis. A dataset from an industrial wastewater treatment facility is used in this study.A diagnostic algorithm has been developed that employs the techniques identified above. An application in Java was constructed which allows the algorithm to be applied, eventually producing an intelligent modelling agent. Thus the focus of this research work was to develop an intelligent dynamic modelling system (using components such as mathematical model, data mining, diagnostic algorithm, and the dataset) for simulation of, and diagnosis of faults in, a wastewater treatment process where different techniques will be assigned different roles in the diagnostic system.Results presented in Chapter 5 (section 5.5) show that the application of this combined technique yields better results for detection and diagnosis of faults in a process. Furthermore, the dynamic update of the set value for any process variable (presented in Chapter 5, section 5.2.1) makes possible the detection of any process disturbance for the algorithm, thereby mitigating the issue of false alarms. The successful embedding of both a detection and a diagnostic technique in a single algorithm is a key achievement of this work, thus reducing the time taken to detect and diagnose a fault. In addition, the implementation of the algorithm in the purposebuilt software platform proved its practical application and potential to be used in the chemical and processing industries.

Philosophiae Doctor - PhD
Persistent organic pollutants (POPs) are very tenacious wastewater contaminants with negative impact on the ecosystem. The two major sources of POPs are wastewater from textile industries and pharmaceutical industries. They are known for their recalcitrance and circumvention of nearly all the known wastewater treatment procedures. However, the wastewater treatment methods which applied advanced oxidation processes (AOPs) are documented for their successful remediation of POPs. AOPs are a group of water treatment technologies which is centered on the generation of OH radicals for the purpose of oxidizing recalcitrant organic contaminants content of wastewater to their inert end products. Circumvention of the reported demerits of AOPs such as low degradation efficiency, generation of toxic intermediates, massive sludge production, high energy expenditure and operational cost can be done through the application of the combined AOPs in the wastewater treatment procedure. The resultant mineralisation of the POPs content of wastewater is due to the synergistic effect of the OH radicals produced in the combined AOPs. Hydrodynamic cavitation is the application of the pressure variation in a liquid flowing through the venturi or orifice plates. This results in generation, growth, implosion and subsequent production of OH radicals in the liquid matrix. The generated OH radical in the jet loop hydrodynamic cavitation was applied as a form of advanced oxidation process in combination with hydrogen peroxide, iron (II) oxides or the synthesized green nano zero valent iron (gnZVI) for the treatment of simulated textile and pharmaceutical wastewater.

The EBPR (Enhanced Biological Phosphorus Removal) is a type of secondary treatment in WWTPs (WasteWater Treatment Plants), quite largely used in full-scale plants worldwide. The phosphorus occurring in aquatic systems in high amounts can cause eutrophication and consequently the death of fauna and flora. A specific biomass is used in order to remove the phosphorus, the so-called PAOs (Polyphosphate Accumulating Organisms) that accumulate the phosphorus in form of polyphosphate in their cells. Some of these organisms, the so-called DPAO (Denitrifying Polyphosphate Accumulating Organisms) use as electron acceptor the nitrate or nitrite, contributing in this way also to the removal of these compounds from the wastewater, but there could be side reactions leading to the formation of nitrous oxides. The aim of this project was to simulate in laboratory scale a EBPR, acclimatizing and enriching the specialized biomass. Two bioreactors were operated as Sequencing Batch Reactors, one enriched in Accumulibacter, the other in Tetrasphaera (both PAOs): Tetrasphaera microorganisms are able to uptake aminoacids as carbon source, Accumulibacter uptake organic carbon (volatile fatty acids, VFA). In order to measure the removal of COD, phosphorus and nitrogen-derivate compounds, different analysis were performed: spectrophotometric measure of phosphorus, nitrate, nitrite and ammonia concentrations, TOC (Total Organic Carbon, measuring the carbon consumption), VFA via HPLC (High Performance Liquid Chromatography), total and volatile suspended solids following standard methods APHA, qualitative microorganism population via FISH (Fluorescence In Situ Hybridization). Batch test were also performed to monitor the NOx production. Both specialized populations accumulated as a result of SBR operations; however, Accumulibacter were found to uptake phosphates at higher extents. Both populations were able to remove efficiently nitrates and organic compounds occurring in the feeding. The experimental work was carried out at FCT of Universidade Nova de Lisboa (FCT-UNL) from February to July 2014.

Organic matter and nutrients present in urban and industrial wastewater should be removed or valorised to reduce its impact on the environment. Conventional wastewater treatments are focused on the removal of these pollution sources at the minimum cost. The idea of resource recovery from wastewater is changing the concept of the conventional wastewater treatment plants that tend to incorporate little by little processes as anaerobic digestion, MBR, biofilm, granulation, etc. However, their application to obtain reusable by-products from wastes should be cost effective. Winery wastewater is an effluent with a highly biodegradable organic load, worth considering for biogas production, and low nutrient content. A sidestream anaerobic membrane bioreactor (AnMBR) was started up and operated under organic load oscillations. The stable operation was assured by keeping a ratio between intermediate alkalinity and total alkalinity (IA/TA) below 0.3 achieving a 96.7±2.7% COD removal efficiency. The biogas production varied according with the OLR that was on average 0.50±0.17 m(3)(biogas)/m(-3)(digester)/d(-1) with an 87.1±3.0% of methane. The external membrane module reached a flux of 20.2 ± 8.5 LMH at a crossflow velocity of 0.64 m s-1. The crossflow velocity helped to remove the cake layer attached on the membrane that was the main contribution (>80%) to flux decline. The energy demand of the AnMBR was calculated considering the net energy production of a combined heat and power (CHP) unit. It was concluded that only when influent COD was over 3.25 gCOD 1:1- the energy balance was positive. Considering the upscaling of the AnMBR of the present study, the submerged membrane configuration would be a more feasible option due to its lower operational costs, especially in winter season. Simulating the conditions of winter season, winery wastewater was treated in the AnMBR at low temperatures of 25°C and 15°C. Since the organic load of winery wastewater in winter is much lower than in summer (vintage season), the average OLR applied was 0.32 and 0.29 kgCOD m(-3)(digester)/d(-1) the average COD removal reached was 80% and 71% at 25°C and 15°C., respectively. Moreover, higher degree of fouling was observed despite the amount of suspended solids was lower, so frequent cleanings were necessary. The effluent of anaerobic digestion often requires a post-treatment to remove nutrients, especially nitrogen. Compared with conventional biological nitrogen removal, nitritation/denitritation (N/DN) via nitrite represent a 25% less aeration and 40% less external carbon source. In order to reach higher flexibility and reducing space requirements, N/DN can be carried out in a sequencing batch reactor (SBR). Under feast and famine conditions applied in the SBR, storage compounds can be served as internal carbon sources for post-anoxic denitrification. A novel scheme was developed for the treatment of municipal wastewater; consisting in an UASB reactor followed by a short cut sequencing batch reactor (scSBR) in the main water line. Nitritation/denitritation was integrated with the selection of polyhydroxyalkanoate (PHA) storing biomass. Biowaste fermented liquid was applied as carbon source in the feast regime. The average nitrogen removal was 83%. After achieving an acceptable ammonia removal of 93%, there was enough available PHA for the subsequent denitritation, reaching a maximum nitrite removal of 98%. The maximum PHA content was 10.6% (gPHA gTSS-1) after 10 h of accumulation when biowaste fermented liquid (C/N/P= 100/4.5/0.42) was applied. Nitrogen removal limits could be successfully met while PHA-storing biomass was selected. Although higher PHA yields can be achieved under complete aerobic conditions, this novel scheme presents an added value due to the integration of the PHA production in the nitritation/denitritation process.
Un dels reptes de les estacions depuradores d'aigües residuals (EDAR) és aconseguir una elevada eficiència d'eliminació de contaminants amb menys demanda energètica, atenent als requeriments legals, cada dia més restrictius. A més a més, l'afany de recuperació de recursos a partir dels residus promou el desenvolupament de noves tecnologies pel tractament d'aigües residuals valoritzant-ne la matèria orgànica i els nutrients que conté. La digestió anaeròbia és un procés pel qual la matèria orgànica es transforma en una font d'energia, com és el biogàs. Actualment, la digestió anaeròbia s'aplica a residus com els fangs de depuradora, purins, etc. En aquesta tesi, s'ha estudiat la digestió anaeròbia per al tractament d'aigües residuals amb poca càrrega orgànica, utilitzant bioreactors de membrana anaeròbics (BRM-An) per tal de retenir la biomassa en el digestor. S'ha tractat aigua residual procedent de la indústria vitivinícola, caracteritzada per un alt contingut en matèria orgànica i pobre en nutrients, avaluant la flexibilitat del BRM-An a oscil•lacions de càrrega orgànica, així com la seva viabilitat en termes energètics. Pel que fa a l'aigua residual municipal, la digestió anaeròbia requereix de post-tractaments d'eliminació de nutrients. En aquesta tesi, s'han estudiat dos processos d'eliminació de nitrogen: nitrificació/desnitrificació (N/DN) via nitrit i nitrificació parcial — Anammox (de l'anglès anaerobic ammonium oxidation). Ambdós possibilitats presenten un estalvi considerable en comparació amb la N/DN convencional. És ben sabut que la N/DN via nitrit suposa una reducció de les necessitats d'aireig i matèria orgànica. En el present treball s'ha estudiat la integració de l'eliminació de nitrogen via nitrit amb la producció de polihidroxialcanoats (PHA), bioplàstics d'alt interès comercial que s'acumulen a l'interior de les cèl•lules donades les condicions adients (sacietat — fam). Tots els estudis s'han portat a terme a escala de laboratori i s'han obtingut conclusions satisfactòries en al majoria de casos, arribant a la conclusió que valoritzant la matèria orgànica present en les aigües residuals com una font de recursos i reduint el cost dels sistemes d'eliminació de nutrients, les EDAR esdevindran processos molt més sostenibles.

The hybrid activated sludge-biofilm system called Integrated Fixed Film Activated Sludge (IFAS) has recently become popular for enhanced nitrification and denitrification in aerobic zones because it is an alternative to increasing the volume of treatment plant units to accomplish year round nitrification and nitrogen removal. Biomass is retained on the fixed-film media and remains in the aerobic reactor, thus increasing the effective mean cell resident time (MCRT) of the biomass and providing the temperature sensitive, slow growing nitrifiers a means of staying in the system when they otherwise would washout. While the utilization of media in aerobic zones to enhance nitrification and denitrification has been the subject of several studies and full-scale experiments, the effects and performances of fixed film media integrated into the anoxic zones of biological nutrient removal (BNR) systems have not adequately been evaluated as well as the impacts of integrated media upon enhanced biological phosphorus removal (EBPR). Also, user-friendly software designed specifically to simulate the complex mixture of biological processes that occur in IFAS systems are not available. The purpose of this research was to more fully investigate the effects of integrated fixed film media on EBPR, to evaluate the impacts of media integrated into the anoxic zone on system performance, and to develop a software program that could be used to simulate the effects of integrating the various types of media into suspended growth biological nutrient removal (BNR) systems. The UCT type configuration was chosen for the BNR system, and Accuweb rope-like media was selected for integration into the anoxic zones of two IFAS systems. The media also was integrated into the aerobic reactors of one of the systems for comparison and for further investigation of the performance of the Accuweb media on enhanced nitrification and denitrification in the aerobic zones. The experiments were conducted at 10 day total MCRT during the initial phase, and then at 6 days MCRT for the experimental temperature of 10 oC. A13 hour hydraulic retention time (HRT) was used throughout the study. A high and a low COD/TP ratio were used during the investigation to further study the effects of integrated media on EBPR. The PC Windows based IFAS program began with the concepts of IAWQ model No. 2 and a zero-dimensional biofilm model was developed and added to predict the IFAS processes. Experimental data from the initial study and existing data from similar studies performed at high temperatures (>10oC) indicated that there were no significant differences in BNR performances between IFAS systems with media integrated into the anoxic and aerobic or only aerobic zones and a suspended growth control system maintained at the same relative high MCRT and temperature values. Even though greater biological nitrogen removal could not be achieved for the experimental conditions used, the experimental results indicated that the IFAS systems with fixed film media installed in the anoxic zone have a greater potential for denitrification than conventional BNR systems. As much as 30 percent of the total denitrification was observed to occur in the aerobic zones of the system installed the media only anoxic zones and 37% in the system with integrated media in both anoxic and aerobic zones where as no denitrification was observed in the aerobic zones of the control system when the systems were operated at 6 days MCRT and COD/TP of 52. It is statistically confirmed EBPR can be maintained in IFAS systems as well as Control systems, but the IFAS processes tend to have more phosphorus release in the anoxic zones with integrated fixed film installed. Further, the combination of split flow to the anoxic zone and fixed film media in the anoxic zone resulted in the decreased EBPR performances in the IFAS system relative to the control system.
Ph. D.

Thesis (M.S.)--West Virginia University, 2008.
Title from document title page. Document formatted into pages; contains viii, 55 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 52-55).

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

This thesis focuses on the study of the global green house gas (GHG) emissions from wastewater systems. Nitrous oxide (N2O) and methane (CH4) are the main GHG directly emitted from wastewater treatment plants (WWTP). In this thesis, different studies were performed in order to determine the N2O production when using different combination of electron acceptors during denitrification. Firstly, three different external carbon sources where used in a mixed denitrifying culture. Secondly, a denitrifying polyphosphate accumulating organism (dPAO) and a denitrifying glycogen accumulating organism (dGAO) enriched cultures were used to assess the effect of using an internal carbon source (polyhydroxyalkanoates, PHA) for denitrification on the N2O production. Results indicated that electron competition during the reduction of different nitrogen oxides is a significant factor in ordinary heterotrophic denitrification processes using external carbon sources as the electron donor, but not in PHA-driven denitrification processes conducted by dPAO or dGAO. Results also showed that generally, higher N2O accumulation was detected in the tests conducted with dGAO than those conducted with dPAO, especially when nitrite was used as electron acceptor. Later, the effect of DO at a constant pH level and the effect of pH at a constant DO level on N2O and NO production in a partial nitrification sequencing batch reactor (SBR) were explored. Also, the relationship between NO production and the ammonia oxidation rate (AOR) as well as the N2O production rate and the AOR were studied. Results showed that these relationships were linear and exponential, respectively. This investigation highlighted the importance of also monitoring NO emissions since they may lead to N2O emissions. The last investigation of this thesis was a long-term full-scale study in the WWTP of Girona in order to assess the N2O and CH4 emission dynamics of the plug-flow reactors. Results showed seasonal and spatial variations on N2O emissions but only spatial variations on CH4 emissions. Finally, the overall carbon footprint of the plug-flow reactor was assessed.
Aquesta tesi està centrada en l'estudi de les emissions dels gasos d'efecte hivernacle (GEH) dels sistemes de tractament d'aigua residual. L'òxid nitrós (N2O) i el metà (CH4) són els principals GEH emesos directament en les estacions depuradores d'aigües residuals (EDAR). En aquesta tesi s'han realitzat diferents estudis per a identificar la producció de N2O usant diferents combinacions d'acceptors d'electrons durant la desnitrificació. En primer lloc es varen utilitzar tres fonts de carboni externes en un cultiu mix desnitrificant. En segon lloc es va utilitzar un cultiu enriquit amb organismes desnitrificants acumuladors de fòsfor (dPAO) i un cultiu enriquit amb organismes desnitrificants acumuladors de glicogen (dGAO) per tal d'avaluar l'efecte d'utilitzar una font de carboni interna (polihidroxialcanoats, PHA) per la desnitrificació en la producció de N2O. Els resultats van indicar que la competició d'electrons durant la reducció dels diferents òxids de nitrogen és un factor significatiu en els processos de desnitrificació heterotròfica ordinària utilitzant fonts de carboni externes com a donador d'electrons però no en els processos de desnitrificació utilitzant PHA com a font de carboni interna com en els dPAO i dGAO. Els resultats també varen demostrar que generalment en els experiments realitzats amb els dGAOs es detectava una acumulació major de N2O que en els experiments amb dPAOs, especialment quan s'utilitzava nitrit com a acceptor d'electrons. Més endavant es va explorar l'efecte del oxigen dissolt (DO) a un nivell constant de pH i l'efecte del pH a un nivell constant de DO en la producció de N2O i NO en la nitrificació parcial en un reactor discontinu seqüencial (SBR). També es va estudiar la relació entre la producció de NO i la velocitat d'oxidació d'amoni (AOR) així com la producció de N2O i la AOR. Els resultats van mostrar que les relacions eren lineal i exponencial, respectivament. Aquesta investigació va destacar la importància de supervisar també les emissions de NO, ja que poden conduir a emissions de N2O. L'última investigació d'aquesta tesi va ser un estudi a l'EDAR de Girona per a avaluar les dinàmiques d'emissions de N2O i CH4 en els reactors de flux pistó. Els resultats van mostrar variacions estacionals i espacials en les emissions de N2O en el reactor de flux pistó però només variacions espacials en les emissions de CH4. Finalment, es va avaluar la petjada de carboni global del reactor flux pistó.

Tese de Doutoramento em Química
This research contributes to the study and development of advanced oxidation technologies applied to two different problematic wastewaters: textile and winery wastewaters. In this dissertation the factors that influence the oxidation of the model compound of textile wastewaters, the azo dye Reactive Black 5 (RB5), and of the winery wastewaters were investigated. The first part of the thesis experimental work is dedicated to the decolorization of RB5 solutions. The RB5 dye was selected as model molecule to represent the concerned dye group because is widely used in the textile and paper industries, hardly biodegradable and inexpensive. Firstly, an experimental comparison among two photoxidation systems, Fenton/UV-C and ferrioxalate/H2O2/solar light, was performed. The variables considered were pH, H2O2 dosage, iron dosage, RB5 concentration and source of light. The experiments indicate that RB5 can be effectively decolorized using Fenton/UV-C and ferrioxalate/H2O2/solar light processes with a small difference between the two processes, 98.1 and 93.2%, respectively, after 30 minutes. Although the lesser difference in dye decolorization, significant increment in TOC removal was found with Fenton/UV-C process (46.4% TOC removal) relative to ferrioxalate/H2O2/solar light process (29.6% TOC removal). This fact reveals that UV-C low pressure mercury lamp although with its small effect on dye decolorization is particularly important in dye mineralization, when compared to solar light. Further, it was tested the decolorization of aqueous azo dye RB5 solution combining an Advanced Oxidation Process (Fenton’s reagent) followed by an aerobic biological process (mediated by the yeast Candida oleophila). Fenton’s process alone, as well as aerobic treatment by Candida oleophila alone, exhibited the capacity to significantly decolorize azo dye solutions up to 200 mg/L, within about 1 and 24 hours respectively. By contrast, neither Fenton’s reagent nor Candida oleophila sole treatments showed acceptable decolorizing abilities for higher initial dye concentrations (300 and 500 mg/L). But the combination between the two processes, with Fenton’s reagent process as primary treatment, at 1.0x10-3 mol/L H2O2 and 1.0x10-4 mol/L Fe2+, and growing yeast cells as a secondary treatment, achieves a color removal of about 91% for an initial RB5 concentration of 500 mg/L. In a second stage, is presented the experimental work done with winery wastewaters. This study starts with the evaluation of the capacity of different Advanced Oxidation Processes (AOP) combined with several radiation sources to degrade the phenolic compound Gallic Acid (GA), the most representative phenolic compound present in the winery wastewaters. From the experiments conducted it was possible to suggest that the AOP, Fe2+ + H2O2 + UV TNN 15/32 (photo-Fenton process), was the most efficient process thereby achieving the GA degradation value of 95.6% in 7.5 minutes and resulting in a total elimination of toxicity. Afterwards, the degradation of simulated winery wastewater was studied in a pilotscale Compound Parabolic Collector (CPC) solar reactor. Total organic carbon (TOC) reduction with heterogeneous photocatalysis (TiO2) and homogeneous photocatalysis with photo-Fenton is observed. Heterogeneous photocatalysis with TiO2, TiO2/H2O2 and TiO2/S2O8 2- is revealed to be inefficient in removing TOC, achieving TOC degradation of 10%, 11% and 25%, respectively, at best. However, photo-Fenton experiments achieved 46% TOC degradation in simulated wastewater prepared with diluted wine (WV) and 93% in wastewater prepared with diluted grape juice (WG), and if ethanol is previously eliminated from mixed wine and grape juice wastewater (WW) by air stripping, it removes 96% of TOC. Ozonation of organic substances present in winery wastewater was studied in a pilot-scale bubble column reactor. A steady reduction of chemical oxygen demand (COD) was observed under the action of ozone at the natural pH of the wastewater (pH 4). At alkaline and neutral pH the degradation rate was accelerated by the formation of radical species from the decomposition of ozone. The monitoring of pH, redox potential (ORP), UV absorbance (254 nm), polyphenols content and ozone consumption was correlated with the oxidation of the organic species in the water. The ozonation of winery wastewater in the bubble column was analysed in terms of a mole balance coupled with ozonation kinetics modeled by the two-film theory of mass transfer and chemical reaction. It was determined that the ozonation reaction can develop both in and across different kinetic regimes: fast, moderate and slow, depending on the experimental conditions. Besides ozonation also the effectiveness of different ozone-based advanced oxidation processes (O3, O3/UV and O3/UV/H2O2) on the treatment of winery wastewater was investigated in the same pilot-scale bubble column reactor. In all the experiments the disappearance of the winery wastewater organic load was described by pseudo-first order apparent reaction kinetics. The faster rate constant (6.5 x 10-3 min-1), at the natural pH of the wastewater, was observed with the O3/UV/H2O2 process under optimised oxidant dose (COD/H2O2 = 2). An economical analysis on the operating costs of the AOPs processes investigated revealed the O3/UV/H2O2 to be the most economical process (1.31 Euro m-3g-1 of TOC mineralised under optimised conditions) to treat the winery wastewater. Finally, the degradation of the organic pollutants present in winery wastewater was carried out by the combination of two successive steps: a long term aerated storage bioreactor followed by a chemical oxidation process using Fenton’s reagent. The long term hydraulic retention time, 11 weeks, contributed remarkably to the reduction of COD (about 90%) and the combination with the Fenton’s reagent led to a high overall COD reduction that reached 99.5% when the mass ratio (R=H2O2/COD) used was equal to 2.5, maintaining constant the molar ratio H2O2/Fe2+=15.
A presente tese de doutoramento pretende contribuir para o estudo e o desenvolvimento de tecnologias de oxidação avançada aplicadas a dois tipos de águas residuais: efluentes têxteis e efluentes vinícolas. O objectivo principal deste trabalho foi o de compreender a aplicação de vários Processos de Oxidação Avançada (POA) e determinar os principais factores operacionais que condicionam a degradação de certos tipos de compostos e a decomposição da matéria orgânica presente em águas residuais têxteis e em efluentes vinícolas. Estes tipos de águas residuais foram seleccionados como alvo de estudo por duas ordens de razões. Em primeiro lugar, porque constituem problemas ambientais relevantes na região Norte de Portugal. De facto, encontra-se um grande número de indústrias têxteis dispersas pelos distritos do Porto e Braga, especialmente na bacia hidrográfica do Ave, enquanto a produção de vinho assume uma particular importância na Região Demarcada do Douro. Em segundo lugar, porque se pretendiam estudar efluentes contendo compostos de origem sintética (designadamente os corantes têxteis) e, em contraponto, estudar águas residuais geradas por processos agrícolas caracterizadas pela presença preponderante de matéria orgânica de origem natural, seleccionando-se, neste caso, os efluentes vinícolas. Estruturalmente, a primeira parte do trabalho é dedicada ao estudo da descoloração de soluções do corante sintético Reactive Black 5 (RB5). O corante RB5 foi seleccionado como composto modelo para representar os corantes têxteis uma vez que apresenta uma difícil biodegradabilidade e é muito utilizado na indústria têxtil. Inicialmente fez-se a comparação experimental entre dois sistemas de foto-oxidação, Fenton/UV-C e ferrioxalato/H2O2/radiação solar. As variáveis consideradas foram: pH, concentração de H2O2, concentração de ião ferroso, concentração de RB5 e fonte de radiação. Os ensaios indicam que as soluções de RB5 podem ser efectivamente descoloradas usando Fenton/UV-C e ferrioxalato/H2O2/radiação solar com uma pequena diferença entre os dois processos, 98,1 e 93,2%, respectivamente, após um período de 30 minutos. Apesar da escassa diferença de descoloração verificada entre os dois POA, é nítido um incremento significativo na remoção de carbono orgânico total (COT) com o processo Fenton/UV-C (46,4% de remoção de COT) comparativamente com o processo ferrioxalato/H2O2/luz solar (29,6% de remoção de COT). Este facto revela que a fonte de radiação utilizada, lâmpada de mercúrio de baixa pressão (UV-C), é particularmente importante na mineralização do corante RB5 quando comparada com a luz solar. Foi depois testada a descoloração da solução aquosa de RB5 com o reagente de Fenton (H2O2/Fe2+) combinado com um processo biológico aeróbio (desenvolvido pela levedura Candida oleophila). O processo Fenton e o tratamento aeróbio pela Candida oleophila mostraram, individualmente, uma capacidade significativa para descolorar soluções de RB5 com concentrações até 200 mg/L, no período de 1 e 24 horas, respectivamente. Por outro lado, nem o reagente de Fenton nem a levedura Candida oleophila apresentaram de per si uma capacidade apreciável para descolorar soluções com concentrações elevadas de corante (300 e 500 mg/L). No entanto, a combinação dos dois processos anteriores: reagente de Fenton, como tratamento primário, utilizando as concentrações de 1,0x10-3 mol L-1 de H2O2 e 1,0x10-4 mol L-1 de Fe2+, com a levedura Candida oleophila, como tratamento secundário, permitiram alcançar uma remoção de cor de aproximadamente 91% para uma concentração inicial de RB5 de 500 mg L-1. Numa segunda fase, é apresentado o trabalho experimental realizado com efluentes vinícolas. Este estudo teve início com a avaliação da capacidade de diferentes POA, quando combinados com várias fontes de radiação, em degradarem o ácido gálico: o ácido fenólico presente em maior quantidade nos efluentes vinícolas e considerado como composto modelo neste estudo. Através dos ensaios realizados foi possível verificar que o processo foto-Fenton (Fe2+ + H2O2 + UV TNN 15/32), foi o que apresentou maior eficiência na degradação do referido ácido, 95,6% em 7,5 minutos. Posteriormente, foi estudada a degradação de um efluente vinícola simulado, numa escala piloto, usando um reactor solar do tipo “Compound Parabolic Collector” (CPC). Foi avaliada a redução do teor em carbono orgânico total (COT) por fotocatálise heterogénea (TiO2) e por fotocatálise homogénea (foto-Fenton). Os ensaios de fotocatálise heterogénea com TiO2, TiO2/H2O2 e TiO2/S2O8 2- revelaram-se ineficientes na remoção de COT atingindo, na melhor das situações, degradações de 10%, 11% e 25%, respectivamente. Nas experiências realizadas com o processo foto-Fenton foi possível atingir 46% de degradação de COT no efluente simulado preparado com vinho diluído e 93% no efluente simulado preparado com sumo de uva. Se o etanol presente no efluente simulado for previamente eliminado por “air stripping” é possível atingir uma remoção de 96% do carbono orgânico total. A ozonização de compostos orgânicos presentes no efluente vinícola foi estudada em escala piloto recorrendo a um reactor “bubble column”. A redução progressiva da carência química de oxigénio (CQO) foi observada através da acção do ozono sobre as águas residuais a pH natural (pH 4). A pH alcalino e neutro a taxa de degradação foi acelerada pela formação de espécies radicais geradas a partir da decomposição do ozono. A monitorização do pH, do potencial de oxidação-redução (ORP), da aromaticidade (absorvância a 254 nm), dos polifenóis totais e do consumo de ozono foram correlacionados com a oxidação das espécies orgânicas na água residual. Estudou-se a ozonização de efluentes vinícolas no reactor “bubble column” em função do equilíbrio molar em conjunto com a cinética de ozonização modelada pela teoria dos dois filmes de transferência de massa e de reacção química. Deduziu-se que a reacção de ozonização pode desenvolver-se em regimes cinéticos diferentes: rápido, moderado e lento, dependendo das condições experimentais. Avaliou-se ainda a eficiência de diferentes POA baseados em ozono (O3, O3/UV e O3/UV/H2O2) no tratamento dos efluentes vinícolas no reactor “bubble column” à escala piloto. A redução da carga orgânica dos efluentes vinícolas foi descrita como uma reacção de pseudo-1ª ordem em todos os ensaios. A constante de velocidade de degradação mais rápida (6,5x10-3 min-1), a pH natural, foi obtida para o processo O3/UV/H2O2 em condições optimizadas (COD/H2O2 = 2). Uma análise económica sobre os custos de operação dos POA investigados revelou que o processo mais competitivo para tratar os efluentes vinícolas é o processo O3/UV/H2O2 (com custos de 1,31 Euro m-3 g-1 de COT mineralizado sob condições optimizadas). Finalmente, estudou-se a degradação da carga orgânica presente em efluentes vinícolas através da combinação de duas etapas sucessivas: uma primeira, envolvendo o tratamento biológico aeróbio com um longo tempo de residência, seguido por um processo de oxidação química utilizando o reagente de Fenton. O tempo prolongado de retenção hidráulica no biorreactor, 11 semanas, contribuiu notavelmente para a redução de CQO (cerca de 90%). A combinação posterior com o reagente de Fenton conduziu a uma redução global de CQO de 99,5% quando a razão mássica aplicada (R = H2O2/COD) foi igual a 2,5, mantendo-se constante a razão molar H2O2/Fe2+ = 15.

碩士
嘉南藥理科技大學
環境工程與科學系碩士班
94
Fenton process is one of advanced oxidation processes. It uses hydrogen peroxide and ferrous ions to produce hydroxyl radicals that can oxidize various types of pollutants. Fenton process take advantage of the high efficiency and low operational cost. However, the primary disadvantage of this process is the generation of high volume of iron sludge. Previous studies showed that applying electric current or crystallization technology effectively reduces the iron sludge generation. Therefore, this study applied Electro-Fenton and Fluidized bed (FB) Fenton processes to treat the synthetic wastewater for comparing the difference between these two systems. Results show that initial pH, ferrous ion, hydrogen peroxide and aniline concentration would affect the degradation of aniline. The reaction rate increased with increasing ferrous ion and hydrogen peroxide concentration. Two-stage model is applied to describe the reaction kinetics. In this study, when initial pH=2.6~3.2, average oxidation rate of aniline were 0.40~ 3.06(×10-3 M min-1) and K for aniline were 0.21~ 0.72 (min-1) for electro-Fenton process. In FB-Fenton process, average oxidation rate for aniline were 0.72~ 2.47(×10-3 M min-1) and K of aniline were 0.06~0.36 (min-1).Reaction rates and removal efficiencies of aniline using different Fenton processes were better at pH 3.2. The average oxidation rate and K increased with increasing ferrous ion and hydrogen peroxide concentration. Average oxidation rate and K decreased with increasing aniline concentration. Anions suppressed the decomposition of aniline in the following sequence: H2PO4> Cl- for both electro-Fenton and Fluidized bed Fenton processes. Multi-step H2O2 addition did not affect the aniline removal efficiency for Electro-Fenton process. However, one-step H2O2 addition was better than multi-step H2O2 addition for FB-Fenton. To compare electro-Fenton and FB-Fenton processes, the following operating conditions were used, namely 〔C H NH 〕＝1.0×10-2M,〔Fe2+〕＝1.07×10-3 M,〔H2O2〕＝0.058 M,〔SiO2〕＝100g, current＝4A, pH＝3.2. After 60 min, aniline removal was 95﹪for electro-Fenton process while 83﹪of aniline was removed by FB-Fenton process. Therefore, aniline oxidation efficiency by Electro-Fenton process is better compared with FB-Fenton process.