The primary objective of this research was to determine if efficient biological phosphorus removal could be established under low sludge retention time of 2 days and a nominal hydraulic retention time of 4 to 6 hours. The two-stage Phoredox process was selected because of the practical application of retrofitting high rate treatment plants to achieve bio-P removal without the additional tankage required for an anoxic section and the additional expense of a recycle system. It has been shown that nitrate recycled into the anaerobic reactor impacts on bio-P removal and the two-stage Phoredox process provides no control over nitrates entering the anaerobic reactor. Therefore a secondary objective of this research was to determine if a low sludge retention time mode of operation could be used as an effective way to prevent nitrification in the activated sludge treatment process. Another objective was to observe mixed liquor settling characteristics of the two-stage Phoredox process operated under high rate conditions. A pilot scale two-stage Phoredox activated sludge treatment process operating under high rate conditions was used to meet these objectives. The desired bio-P removal biomass was not observed under SRT operating conditions of 2, 3 and 5 days. Partway into the research a sludge bulking condition developed which was identified as filamentous growth. On two occasions this severe filamentous growth resulted in the process failing and the system being restarted. On one occasion after the system was restarted using a seed sludge from a three-stage Phoredox pilot plant, a bio-P removal biomass was present. This condition only lasted for a short period and ended as filamentous growth began to become dominant. The process failed because of this phenomenon. The system was restarted using a seed sludge and again filamentous growth dominated. Chlorine addition was found to be the only method to control this phenomenon and was continued to the end of the research. The desired bio-P removal biomass was not observed even during the last period of the research when the SRT was increased to 8 days. During this research a stable bio-P removal biomass was not established. For a short period a bio-P removal biomass was present but failed to persist. Nitrification never became established at any time. Sludge settleability was poor due to filamentous growth which developed partway into the research and was present throughout the remainder of the study. Chlorine addition was the only method found that remedied this settling problem. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The objective of this research was to optimize the bio-P process as applied to a weak sewage with respect to HRT in each of the process zones. This goal was to be achieved by changing the HRT of the various zones with all other operating characteristics being held constant. The experimental work during this study involved two initially identical process trains operated in the University of Cape Town (UCT) mode. The aerobic zones of both trains were divided into four equal sized complete-mix cells to allow observations of phosphate uptake and poly-β-hydroxyalkanoate (PHA) consumption under aerobic conditions. After steady-state was established, the anaerobic HRT was reduced to 50% of the original value in the experimental module by reducing the anaerobic reactor volume. At the same time, the mixed liquor of both trains was drained, mixed and reapportioned to the two processes, thereby assuring equivalent starting conditions. Results of this study showed that both processes performed identically prior to the anaerobic HRT change. After the anaerobic HRT change, there was a forty day period where P removal and effluent P were the same in both process trains. This was so, even though the anaerobic P release was considerably less in the experimental module. Subsequently, a change in influent sewage type corresponded to a change in P removal and effluent P in the two process trains. An examination of the process parameters showed that the anoxic zone of the experimental module, after the anaerobic HRT change and the sewage change, consistently removed less P or released more P than in the control module. As a result, the control module out-performed the experimental module. Batch tests and tests to better characterize the influent sewage were then conducted in an attempt to determine the reasons for the different P removal characteristics. Under the test conditions, it appeared that the original anaerobic HRT was excessive. This was preferable to an insufficient anaerobic HRT, such as in the experimental module, however. The anoxic zone may have been too large, too small or just right for optimum P removal depending on the influent sewage characteristics. Optimizing the bio-P process by reducing the aerobic zone HRT appeared to have the greatest potential. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This thesis explains a method based on the homogenisation of zeta potential charges on carbon supports for the production of hierarchical structured zeolitic composites. The modification of carbons’ surface chemistry allowed zeolite particles to be fixed to the support by electrostatic interactions. In order to achieve this, the size reduction of zeolite particles was carried out by two different methods: a) ball milling and b) a synthetic route to produce zeolite colloidal dispersions. Also, the seeding method, based on hydrothermal growth was compared. The prepared materials in this work were designed to be used in the sorption of cations, and to allow vitrification and thereby reduce the final adsorbent volume. Results showed that a large pollutant amount can be trapped using a lower volume of material reducing costs and final waste disposal. The zeolites used in this work were selected based on their low density framework and low Si/Al ratio. Synthetic zeolites A, Y and clinoptilolite were successfully produced. Natural clinoptilolite was also utilised in this work. Also, zeolite A was produced at nanometre scale following the clear solutions method. All materials were successfully incorporated onto supports to produce multimodal porosity materials. The hierarchical modification of natural clinoptilolite, following a straightforward and nonexpensive methodology, is one the most significant contributions of this work. Carbons are used as supports due to their high surface area, they can be obtained from low-cost sources such as agroindustrial wastes and carbons allow volume reduction if materials are vitrified at high temperatures. In this work, carbons were produced from corn cob and husk, sugar cane bagasse, cherry stones, date stones and hazelnut shells. The prepared composite materials were tested in the removal of toxic ions from water solutions: cobalt, copper and caesium ions were effectively removed from aqueous media. Adsorption experiments showed that the distribution of supported zeolite particles improved their uptake efficiency and capacity. The kinetic studies revealed an enhanced rate constant for carbon-zeolites composites in comparison with pure zeolites. Diffusivity results suggested that mass transfer characteristics are modified by using hierarchical porous materials; results showed that particle size or support nature can modify diffusion resistances, reducing intraparticle diffusion and accelerating the overall kinetic processes. Adsorption equilibrium data was correlated using Langmuir and Freundlich models.

This thesis assesses the potential for enhanced biological phosphorus (Bio-P) removal in Canadian wastewater treatment plants. Retrofit designs incorporating Bio-P removal were prepared for nine wastewater treatment plants across Canada, and were compared against chemical phosphorus removal technologies. Incremental capital and operating costs were calculated and internal rates of return (IRR's) for the capital investment required to install the Bio-P removal facilities were calculated. Based on these results, an assessment of the potential use for the technology in Canada is made. Of the nine plants studied, results indicate that Bio-P removal is economically superior to chemical phosphorus removal for the Calgary Bonnybrook, Edmonton Gold Bar, Saskatoon Mclvor Weir and Regina wastewater treatment plants. In general, Bio-P removal appears to offer significant economic advantages to plants located in Alberta and Saskatchewan because of the high cost of phosphorus removal chemicals in these provinces. The present low cost of phosphorus removal chemicals in Ontario and Quebec likely limits the viability of Bio-P removal to large (greater than 300,000 m³/d), suitably configured plants. In British Columbia, where Bio-P removal is presently used in the Okanagan Valley, the absence of widespread provincial phosphorus removal standards makes future Bio-P installations unlikely. The potential for Bio-P removal in Manitoba, the Maritimes and the Yukon and Northwest Territories is again limited by the absence of phosphorus removal standards in these parts of Canada. Results also indicate that the use of an anoxic/anaerobic/ aerobic process in the bioreactor, in conjunction with primary sludge fermentation through gravity thickening, is very applicable to Canadian plants and offers potential capital and operating cost savings relative to other Bio-P processes. The common practice of anaerobic sludge digestion, combined with sludge dewatering and land application, was found to be unfavourable from a Bio-P perspective unless the resulting supernatant/filtrate streams can be re-used or disposed of outside of the mainstream treatment process. Through the preparation of the retrofit designs, it was determined that certain aspects of Bio-P technology require additional research in order to optimize treatment plant design. These include kinetic modelling; short SRT Bio-P removal; the anorexic/anaerobic/aerobic process; the use of gravity thickening for primary sludge fermentation; and phosphorus release during anaerobic digestion. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

M.Sc. (Chemistry) / Please refer to full text to view abstract

This paper investigates the role of tattoo removal in postmodernity. Specifically, I suggest tattoo removal is a technology of self in which the tattooed person can attain absolution from a "sinful" tattoo. This paper explores the construction of the confessional act in two parts: the construction of the confessing subject and the construction of the medical clinic as the confessor's listener. Using the texts medical offices place on the internet to advertise their services, I investigate the text's interpellation of subjects desiring tattoo removal. I then examine the construction of the clinic's status in the confessional act. Websites and brochures on gang tattoo removal provide a dialogue in which the clinic negotiates and attains its powerful position in the confessional act. The paper concludes by investigating the implications of the tattoo remnant, the material effects of the technology of self, and the benefits of studying the body-skin in rhetoric.

O bisfenol-A (BPA), um monômero usado na fabricação de resinas epóxi e de plásticos de policarbonato, é considerado um potente desregulador endócrino que provoca diversas doenças. O objetivo deste trabalho foi estudar a remoção de BPA, de soluções aquosas através da técnica de adsorção em batelada e em processo contínuo. Também foi investigada a capacidade de regeneração do sorvente utilizado nos testes em batelada. Para isso, foram testados diferentes adsorventes (zeólita em pó e granular modificada com quitosana, zeólita sódica e carvão ativado granular), a fim de determinar qual apresentaria maiores índices de remoção de BPA. Posteriormente foram realizados ensaios de sorção com o sólido escolhido objetivando encontrar as condições mais adequadas de processo considerando os parâmetros de pH, tempo de residência, concentração de sólido sorvente. Ainda, isotermas de equilíbrio para este sistema foram construídas. A adsorção em leito fixo foi avaliada em experimentos via planta piloto de adsorção, segundo a influência de três variáveis: efeito da massa de adsorvente utilizada (5g e 10g), vazão de alimentação (15 mL.min-1 e 20 mL.min-1) e concentração inicial (50 mg.L-1 e 100 mg.L-1). Na regeneração do carvão ativado saturado com BPA, empregaram-se como solventes acetona, n-pentano e diclorometano e também foi utilizada a técnica de ultrassom. As condições de sorção utilizadas foram: pH 6, tempo 60 min, concentração de sorvente 10 g.L-1 e soluções de BPA 10 mg.L-1. A microestrutura externa e a composição elementar semi-quantitativa do carvão ativado antes e após o processo de sorção e regeneração foram analisadas pela técnica de MEV-EDS. No que se refere à sorção, melhores resultados foram encontrados com o carvão ativado granular, atingindo eficiência de remoção de 56,7% em pH 7. O modelo de isoterma de sorção que melhor se ajustou aos dados experimentais foi o modelo de Sips, que forneceu a constante de energia ou afinidade do processo e também a acumulação máxima de BPA no sorvente. Os testes de regeneração mostraram que os melhores agentes regenerativos foram a acetona (100%), com eficiência de remoção de 105,6% e a técnica de ultrassom, a qual apresentou uma eficiência de remoção de 106,4% após um tempo de contato de 30 min. Por ser uma técnica que não gera resíduo, optou-se utilizar o ultrassom para os testes de regeneração em ciclos. O ensaio de tempo de regeneração em banho de ultrassom mostrou que para os tempos de 30, 40, 50 e 60 min de contato a regeneração era muito semelhante. Assim, para os testes de ciclos de sorção-regeneração o tempo de contato utilizado foi de 30 min. Os ensaios de regeneração em ciclos mostraram que após seis (6) ciclos a eficiência de regeneração do sólido sorvente foi de 67,8% e a remoção de BPA obtida ao final desses ciclos foi de 60,9%. Quanto à caracterização do sorvente, as micrografias mostraram que o carvão ativado, antes e após os ciclos de sorção/regeneração (S/R), possui superfícies bastante irregulares, heterogêneas e desordenadas, com elevada porosidade. Ensaios realizados em planta piloto de adsorção mostraram a viabilidade técnica de aplicação do carvão ativado para remoção de bisfenol em processos contínuos, tendo sido possível obter as condições operacionais e a curva de ruptura do sistema. Os resultados indicaram que a adsorção em leito fixo apresentou melhores resultados nas seguintes condições: vazão de alimentação de 20 mL.min-1, concentração inicial de 100 mg.L-1 e 10g de sólido sorvente. / The bisphenol-A (BPA), a monomer used in the manufacture of epoxy resins and polycarbonate plastics is considered a powerful endocrine disrupter which causes various diseases. The objective of this work was to study the removal of BPA from aqueous solutions by adsorption technique in batch and continuous process. The regeneration capacity of sorbents used in batch tests was also investigated. For this purpose, different adsorbents were initially tested (zeolite powder and granular modified with chitosan, sodium zeolite and granular activated carbon) in order to determine which one presents higher removal rates of BPA. After that, sorption tests were carried out with the chosen solid aiming to find the best process conditions considering pH, residence time and sorbent concentration. Hence, equilibrium isotherms were constructed for this system. The fixed bed adsorption was evaluated through adsorption experiments using a pilot plant, according to the influence of three variables: the effect of the mass of the used adsorbent (10g and 5g), flow rate (15 mL.min-1 and 20 mL.min-1) and initial concentration (50 mg.L-1 and 100 mg.L-1). In activated carbon regeneration it was employed acetone, n-pentane and dichloromethane as solvents and the ultrasound technique was also used. The applied sorption conditions were the following: pH 6, time 60 min, sorbent concentration of 10 g.L-1 and BPA solution of 10 mg.L-1. The external microstructure and semi-quantitative elemental composition of the activated carbon before and after the sorption and regeneration were analyzed by SEM-EDS technique. Concerning sorption, the best results were found with granular activated carbon, reaching removal efficiency of 56.7% at pH 7. The sorption isotherm model that best fit the experimental data was the Sips model, which provided constant energy or affinity of the process and also the maximum accumulation of BPA in the sorbent. The regeneration tests showed that the best agents of regeneration were acetone (100%), with removal efficiency of 105.6% and the ultrasound technique, which presented a removal efficiency of 106.4% after a contact time of 30 min. Considering that the technique doesn’t generates waste, it was decided to use the ultrasound tests for regeneration cycles. The regeneration test time in ultrasound bath showed that for contact times of 30, 40, 50 and 60 min the regeneration was very similar. Thus, for testing cycles of sorption-regeneration, the used contact time was 30 minutes. The regeneration cycle tests showed that after six (6) cycles of regeneration efficiency of the solid sorbent was 67.8% and the removal of BPA obtained at the end of these cycles was 60.9%. Regarding characterization of the sorbent, the micrographs showed that the activated carbon before and after cycles of sorption/regeneration (S/R), has very irregular, heterogeneous and disordered surfaces with high porosity. Tests carried out in a pilot plant adsorption showed the technical viability of application of the activated carbon for removal of bisphenol in continuous processes, thus it is possible to obtain operating conditions and the breakthrough curve for this system. These results indicate that the fixed bed adsorption presents best results in the following conditions: feed flow rate of 20 mL.min-1, initial concentration of 100 mg.L-1 and 10 g of solid sorbent.

A espécie Campomanesia phaea (O. Berg.) Landrum é popularmente conhecida como \"cambuci\". É uma das diversas espécies brasileiras de Myrtaceae com fruto comestível e ocorre nos estados de Minas Gerais e São Paulo, principalmente na Serra do Mar. Os frutos possuem intenso aroma agradável e são importantes fontes de compostos fenólicos. Apesar do excelente sabor e aroma do cambuci, a alta adstringência dos frutos, devido ao elevado conteúdo de taninos, reduz a sua aceitabilidade e aplicabilidade na indústria alimentícia. Uma maneira eficaz para remoção da adstringência é submeter o fruto a um processo de destanização, tal como atualmente utilizado para o caqui. O objetivo deste trabalho foi avaliar a variabilidade dos frutos provenientes de uma mesma região e de diferentes regiões, caracterizar frutos em diferentes estádios de maturação, avaliar a eficiência de tratamentos de destanização e determinar o efeito da destanização sobre o potencial funcional, através da determinação do teor e perfil de compostos fenólicos, capacidade antioxidante in vitro e inibição das enzimas do metabolismo de carboidratos. Os tratamentos testados foram: câmaras de etileno, câmara de etanol, ambiente anóxico, etanol no cálice e imersão em etanol. Os resultados mostram que frutos de uma mesma localidade apresentam variações no tamanho e na acidez. Frutos de diferentes regiões apresentaram variação significativa nos teores de fenólicos totais, minerais e na capacidade antioxidante. Com a maturação não foi observado grande variação no teor de sólidos solúveis totais e nem na acidez, porém o conteúdo de fenólicos decresce do estádio mais jovem para o mais maduro. Os processos de destanização com vapor e imersão em etanol foram os mais eficientes na redução do conteúdo de taninos, no entanto esses processos reduziram a capacidade antioxidante e a capacidade de inibição das enzimas α-amilase e α-glicosidase dos frutos. / The specie Campomanesia phaea (O. Berg.) Landrum is popularly known as \"cambuci\". It is one of several Brazilian species of Myrtaceae with edible fruit and occurs in the states of Minas Gerais and São Paulo, especially in the mountains of the sea. The fruits have an intense aroma and are important sources of phenolic compounds. Despite the excellent flavor and aroma of cambuci, high astringency of the fruit, due to the high tannin content, reduces its acceptability and applicability in the food industry. An effective way to astringency removal is to submit the fruit to a deastringency process, as currently used for the persimmon. The aim of this study was to evaluate the variability of the fruits from the same region and from different regions, characterize fruits in different maturation stages, evaluate the efficiency of treatments to astringency removal, and determine the effect of astringency removal about the functional potential, by determining the content and profile of phenolic compounds, antioxidant capacity, and in vitro inhibition of enzymes of carbohydrate metabolism. Treatments tested for removing the astringency were: ethylene chamber, ethanol chamber, anoxic environment, ethanol in the cup, and immersion in ethanol. The results showed that fruit in the same locality exhibit variations in size and acidity. Fruits from different regions showed significant variation in levels of total phenolics, minerals and antioxidant capacity. During maturation it was not observed a wide variation in the content of total soluble solids and acidity, but the phenolic content decreased from the younger stage to the more mature stage. The processes of detannization with ethanol steam and dipped in ethanol were the most effective in reducing the tannin content, however these processes led to reduced antioxidant capacity and capacity of inhibition of the enzymes α-amylase and α-glucosidase in fruits.

[EN] Anaerobic membrane bioreactors for urban wastewater treatment present interesting advantages when compared with aerobic treatments, such as less sludge production, lower energy demand and biogas generation. However, the generated effluent cannot generally be discharged without further ammonium and phosphate elimination. This thesis studies the removal of these inorganic nutrients by means of microalgae cultivation. The main objective of this work is therefore to obtain an autochthonous microalgal culture and to investigate its ability to grow on an already existing anaerobic effluent, as well as to research the extent to which ammonium and phosphate can be removed. Moreover, this thesis aims at providing the kinetic expressions which reproduce the main processes involved, in order to provide the basis for process simulation and design. Microalgae were isolated from a local wastewater treatment plant and their ability to grow on the anaerobic effluent -while successfully removing ammonium and phosphate- was demonstrated. An excellent water quality was obtained with a semicontinuous cultivation mode under constant illumination. The Scenedesmus and Chlorococcum genus proliferated more efficiently and thus became predominant in the culture. Results also showed that phosphorus was the limiting nutrient in the anaerobic effluent to be treated. The influence of phosphorus limitation on ammonium and phosphate removal, as well as the influence of temperature in ammonium removal, were then studied under laboratory conditions. Kinetic expressions which reproduce the observed effects were proposed and validated, taking also into account the effect of light intensity. Additionally, a Scenedesmus-dominated culture was grown under varying light and temperature in an outdoor flat-plate photobioreactor, with constant monitoring of light intensity, temperature and ammonium concentration. Acceptable results were obtained in the reproduction of the experimental data, albeit with less accuracy than under laboratory conditions. The work here presented demonstrates the feasibility of coupling a microalgal cultivation system to an anaerobic membrane bioreactor for urban wastewater treatment. The basic factors affecting microalgal nutrient removal are researched, and mathematical models are provided which reproduce these effects. This Ph.D. thesis is enclosed in a national research project funded by the Spanish Ministry of Economy and Competitiveness entitled "Estudio experimental de la recuperación como biogás de la energía de la materia orgánica y nutrientes del agua residual, acoplando un AnBRM y un cultivo de microalgas" (MINECO project CTM2011-28595-C02-01/02). This research was also supported by the Spanish Ministry of Education, Culture and Sport via a pre doctoral FPU fellowship to the author (AP2009-4903) / [ES] En el tratamiento de aguas residuales urbanas, los bioreactores anaerobios de membranas presentan ventajas interesantes frente a los tratamientos aerobios. Algunas de estas ventajas son la menor producción de fangos, un menor consumo energético y la producción de biogás. Sin embargo, y generalmente, el efluente obtenido no puede ser vertido al medio sin una etapa previa de eliminación de amonio y fosfato. La presente tesis estudia la eliminación de dichos nutrientes inorgánicos empleando para ello un cultivo de microalgas. El objetivo principal de este trabajo es, por tanto, la obtención de un cultivo autóctono de microalgas y la evaluación de la capacidad que éstas tienen tanto de crecer en un efluente anaerobio como de eliminar el amonio y el fosfato presentes. Asimismo, se pretenden proporcionar las bases para la simulación y el diseño del sistema de depuración propuesto, mediante la obtención de las expresiones cinéticas que reproducen los principales procesos involucrados. En primer lugar se ha demostrado la capacidad de las microalgas, aisladas en una estación depuradora de aguas residuales, de crecer en el efluente anaerobio y de eliminar con éxito el amonio y fosfato en éste presente. El agua tratada, obtenida a mediante un proceso semicontinuo y con iluminación constante, presenta una excelente calidad. Los géneros Scenedesmus y Chlorococcum han proliferado más eficientemente y han llegado a ser los predominantes en el cultivo. Los resultados obtenidos indican que el nutriente limitante en el efluente a tratar es el fósforo, y por tanto la influencia de la limitación de fósforo en la eliminación de nutrientes ha sido estudiada en condiciones de laboratorio, junto con la influencia de la temperatura en la velocidad de eliminación de amonio. Han sido propuestas y validadas las correspondientes expresiones cinéticas que reproducen los efectos observados, teniendo en cuenta en todo momento la influencia de la intensidad de la luz. Por otro lado, un cultivo de Scenedesmus ha sido cultivado en el exterior, bajo condiciones cambiantes de luz y temperatura, que a su vez han sido monitorizadas constantemente, junto con la concentración de amonio. Los datos obtenidos han sido reproducidos mediante modelación matemática con resultados aceptables, aunque la precisión obtenida es menor que en condiciones de laboratorio. La presente tesis demuestra la viabilidad de combinar un cultivo de microalgas con un bioreactor de membranas para el tratamiento de agua residual urbana. Se exponen asimismo los factores básicos que influyen en la velocidad de eliminación de nutrientes, y se presentan los modelos matemáticos necesarios para reproducir los efectos observados. La presente tesis doctoral se incluye en el marco de un proyecto nacional de investigación financiado por el Ministerio de Economía y Competitividad de título "Estudio experimental de la recuperación como biogás de la energía de la materia orgánica y nutrientes del agua residual, acoplando un AnBRM y un cultivo de microalgas" (CTM2011-28595-C02-01/02). La presente tesis doctoral ha sido también financiada por el Ministerio de Educación, Cultura y Deporte a través de una ayuda para contratos predoctorales de Formación del Profesorado Universitario (AP2009-4903). / [CAT] En el tractament d'aigües residuals urbanes, els bioreactors anaerobis de membrana tenen avantatges interessants respecte als tractaments aerobis. Alguns d'aquests avantatges són: menys producció de fangs, menys consum energètic i la producció de biogàs. No obstant això, i en general, l'efluent obtingut no es pot tornar al medi sense una etapa prèvia d'eliminació d'amoni i fosfat. Aquesta tesi estudia l'eliminació d'aquests nutrients inorgànics emprant per a fer-ho un cultiu de microalgues. L'objectiu principal d'aquest treball és, per tant, l'obtenció d'un cultiu autòcton de microalgues i l'avaluació de la capacitat que aquestes tenen tant de créixer en un efluent anaerobi com d'eliminar l'amoni i el fosfat presents. Així mateix, volem proporcionar les bases per a la simulació i el disseny del sistema de depuració proposat, mitjançant l'obtenció de les expressions cinètiques que reprodueixen els principals processos involucrats. En primer lloc, s'ha demostrat la capacitat de les microalgues, aïllades en una estació depuradora d'aigües residuals, de créixer en l'efluent anaerobi i d'eliminar amb èxit l'amoni i el fosfat presents. L'aigua tractada, obtinguda mitjançant un procés semicontinu i amb il·luminació constant, presenta una qualitat excel·lent. Els gèneres Scenedesmus i Chlorococcum han proliferat més eficientment i han arribat a ser els predominants en el cultiu. Els resultats obtinguts indiquen que el nutrient limitant en l'efluent per tractar és el fòsfor, i per tant la influència de la limitació de fòsfor en l'eliminació tant d'amoni com de fosfat ha sigut estudiada en condicions de laboratori, juntament amb la influència de la temperatura en la velocitat d'eliminació d'amoni. S'han proposat i validat les expressions cinètiques corresponents que reprodueixen els efectes observats, tenint en compte en tot moment la influència de la intensitat de la llum. D'altra banda, s'ha cultivat a l'exterior un cultiu predominat per Scenedesmus, sota condicions canviants de llum i temperatura, que al seu torn s'han monitorat constantment, juntament amb la concentració d'amoni. Les dades obtingudes s'han reproduït mitjançant simulació matemàtica amb resultats acceptables, encara que la precisió obtinguda és més baixa que en condicions de laboratori. La nostra tesi demostra la viabilitat de combinar un cultiu de microalgues amb un bioreactor de membrana per al tractament d'aigua residual urbana. La tesi exposa així mateix els factors bàsics que influeixen en la velocitat d'eliminació de nutrients, i presenta els models matemàtics necessaris per a reproduir els efectes observats. Aquesta tesi doctoral s'inclou en el marc d'un projecte nacional de recerca finançat pel Ministeri d'Economia i Competitivitat amb el títol "Estudio experimental de la recuperación como biogás de la energía de la materia orgánica y nutrientes del agua residual, acoplando un AnBRM y un cultivo de microalgas" (CTM2011-28595-C02-01/02). La tesi doctoral ha sigut també finançada pel Ministeri d'Educació, Cultura i Esport a través d'una ajuda per a contractes predoctorals de formació del professorat universitari (AP2009-4903). / Ruiz Martínez, A. (2015). Nutrient removal from an anaerobic membrane bioreactor effluent using microalgae. Study and modeling of the process [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/59409 / TESIS

Passive reactive filters have the potential to provide effective phosphorus (P) removal from stormwater or agricultural drainage, or to act as an add-on P-removal technology for decentralized or small community wastewater treatment systems. Passive filters require minimal energy consumption and human maintenance. Direct-reduced iron (DRI), a steel-making intermediate, was investigated as a passive filter media for wastewaters phosphorus reduction. Phosphorus is a biologically active element that is in excess in many natural waterways due to intensive human activity. Eutrophication can occur when P concentrations exceed 0.02 mg/L in freshwater lakes and rivers. The harmful consequence of this phenomenon includes oxygen deprivation, fish death and cyanobacteria-produced toxins. There is a pressing need to limit phosphorus over-discharge into natural waterways. DRI is a novel media in the application of wastewater treatment and was characterized to have a porous structure with high metallic iron content. The phosphorus retaining mechanisms in batch and column studies suggest a combination of adsorption and surface crystal formation as the dominant removal mechanisms. Batch studies demonstrated increasing removal capacity with P concentration with a plateau observed at 21 mg P/g DRI relating to initial 3000 mg P/L. Media rejuvenation was investigated through chemical treatment with two iron solutions (Fe2(SO4)3, FeCl3) and two acidic solutions (H2SO4 and HCl) at varying molarity. P removal capacity could be fully recovered with 0.05 M Fe3+ or 0.4 N H+ (HCl/H2SO4), while a 37.6% P recovery was also achieved in an acidic solution at 1.2 N H+ (HCl/H2SO4). A column study utilizing three media sizes of DRI (3.5, 11, 19 mm) and one media size of activated alumina (AA) (7.5 mm) was conducted for 315 days using synthetic P solution varying from 2 to 10 mg/L and hydraulic retention times (HRTs) varying from 0.7 – 15 h. The results demonstrated that removal efficiency increased with HRT and decreased with increasing media size and concentration with minimum HRTs to maintain an 80% removal efficiency varying from 4.4 to 15 hrs for DRI and 3.9 hrs for AA for influent P concentrations of 10 mg/L and below. After 1 year of column operation, the DRI media had demonstrated a minimum removal capacity of 1.82 mg P/g DRI, which can be used as a conservative design parameter. A short duration column study (34 days) utilizing municipal lagoon effluent exhibited similar removal efficiencies to the synthetic column study under the same operational conditions. The 10 years lifespan DRI filter with 80% removal rate in the treatment of stormwater, municipal lagoon effluent, septic tank effluent and dairy wastewater application would have been estimated to have filter volumes of 0.24, 4.69, 15.3 and 36.2 m3, respectively.