South Africa is a water-scarce country and over the years, the quality of water resources has deteriorated due to poor effluent discharge, agricultural, industrial, mining and human activities. The major contributing factors of poorly-treated or inadequately treated wastewater may be attributed to: (a) the poor design and construction of wastewater treatment plants; (b) lack of qualified process controllers; (c) non-compliance with applicable legislation; (d) lack of proper monitoring; and (e) management issues with regard to wastewater treatment plants. Water quality is important as many communities depend on water resources for their daily activities and livelihood. There is a need therefore to build and manage wastewater treatment plants effectively as they have an impact on water quality. Wastewater treatment plants in South Africa are regulated by the Constitution of the Republic of South Africa, 1996, the National Environmental Management Act 107 of 1998, the National Water Act 36 of 1998, the Water Services Act 108 of 1997, Provincial legislation, Municipal by-laws and other Government policies applicable to Local Government. Chapter 7 of the Constitution inter alia, provides that Local Government has the duty to provide a safe and healthy environment to its community in a sustainable manner. Schedule 4B of the Constitution imposes the function of delivering water, sanitation and wastewater treatment services on Municipalities. This responsibility rests on District Municipalities but may be performed by a Local Municipality if the district municipality lacks the capacity to do so. Although Local Government has the right to govern on its own initiative the affairs of its communities, it needs support and monitoring from other spheres of Government (National and Provincial) to ensure the delivery of wastewater treatment services in a sustainable manner. In this study, Ba-Phalaborwa Local Municipality is used as an example of a Municipality in the Limpopo Province faced with challenges related to the operation and management of its wastewater treatment plant. This study aims to determine who should be responsible for the regulation of wastewater treatment plants in Ba-Phalaborwa Local Municipality area in order to ensure service delivery to communities in a sustainable manner. In order to deal with the challenges experienced by Local Government in dealing with wastewater treatment plants, the study considers Best Practice Guidelines and external service delivery mechanisms, specifically in the form of Public-Private Partnerships. The study concludes with recommendations based on Best Practice Guidelines which Municipalities can use to avoid wastewater pollution and proposes management mechanisms in managing a Public-Private Partnership effectively in order to ensure that they provide service delivery in a sustainable manner. / LLM (Environmental Law and Governance), North-West University, Potchefstroom Campus, 2014

L’estuaire de la Gironde est le plus grand estuaire macrotidal d’Europe formé par la confluence de la Garonne (où se situe l’agglomération de Bordeaux) et de la Dordogne. L’une de ses principales caractéristiques est la présence d’une zone à forte turbidité (bouchon vaseux) où les processus hétérotrophes (dégradation de la matière organique) sont favorisés et où au contraire les processus autotrophes (production primaire) sont limités par le manque de lumière. Ainsi, des déficits en oxygène pouvant être préjudiciables à la vie aquatique se développent systématiquement dans la zone du bouchon vaseux de la Garonne estuarienne. Ces préoccupations environnementales ont donc conduit à étudier en détail dans le cadre de ce travail de doctorat, les facteurs environnementaux qui provoquent ces hypoxies estuariennes. Dans un premier temps, j’ai réalisé un suivi sur le réseau d’eaux urbaines partiellement séparatif et unitaire de la Communauté Urbaine de Bordeaux, de ses stations d’épurations et déversoirs d’orage afin d’appréhender les apports urbains de matières organique et azotées et de les comparer à ceux en provenance du bassin versant amont. Bien que les deux stations d’épuration réalisent des abattements très significatifs sur la matière organique et l’ammonium, il s’avère que les flux vers le milieu naturel restent importants, notamment durant les périodes estivales, pendant lesquelles des orages peuvent engendrer des déversements d’effluents non traités. Ensuite, des expériences d’incubations ont permis de mettre en évidence le caractère fortement labile de cette matière organique urbaine. Le carbone organique dissous et l’ammonium, contenus dans les eaux usées, sont des composés fortement consommateurs en oxygène. Des expériences de respirométrie ont également permis d’estimer les taux de consommation en oxygène nettement plus importants dans les effluents urbains que dans les eaux de la Gironde. Enfin, l’analyse des données du réseau de mesures en continu de la qualité physico-chimique des eaux MAGEST (MArel Gironde ESTuaire) a démontré que l’estuaire subit dans sa section garonnaise des périodes d’hypoxie lors d’étiages prononcés, la masse d’eau la plus affectée par ces désoxygénations étant celle qui oscille aux alentours de l’agglomération de Bordeaux. Si ces résultats démontrent l’impact significatif de l’agglomération Bordelaise, le traitement statistique des données MAGEST pour la période 2005-2011 montre que les phénomènes de désoxygénation sont accrus en période d’étiage prononcé, en présence du bouchon vaseux et lorsque la température de l’eau est élevée. Dans ces conditions, l’oxygène dissous, déjà présent en faible quantité, peut être rapidement consommé lors d’apports supplémentaires d’eaux urbaines non traitées qui ont lieu pendant de fortes précipitations orageuses. Ce travail démontre également que le type de traitement biologique des eaux usées employé par les stations d’épuration et les capacités de stockage temporaire d’eaux d’orages ont un rôle critique sur les bilans de ces composés rejetés dans le milieu naturel. Enfin, ce travail permet de proposer aux gestionnaires des stratégies de rejets des effluents à court et moyen terme, en fonction des conditions hydrologiques et physico-chimiques du milieu, dans le but de limiter leur impact sur l’oxygénation des eaux estuariennes de la Garonne. / The Gironde Estuary is the largest macrotidal estuary in Western Europa, formed by the Garonne River (where the urban area of Bordeaux is located) and the Dordogne River. One of its main characteristics is the presence of a Turbidity Maximum Zone (TMZ) where heterotrophic processes (organic matter decomposition) are favored and where low penetration of light limits autotrophic processes (photosynthetic activity). Low dissolved oxygen (DO) that could impact aquatic biota occurred exclusively in the fluvial, low salinity and high turbidity sections of the estuary. These environmental concerns have led to study in detail in this work factors that cause estuarine hypoxia. First, I have estimated organic matter and ammonium fluxes from urban inputs in separate and combined sewer network of the Urban Community of Bordeaux, its wastewater treatment plants (WWTP) and combined sewer overflow, to compare them to the upstream watershed inputs. Even if the two WWTPs succeed in significant reduction in organic matter and ammonium contents of effluents, discharges into estuarine waters are important especially during summer, periods while storm events can generate untreated effluent inputs. This work demonstrates the high lability of this urban organic matter through incubation experiments. The dissolved organic carbon and ammonium contents in wastewater consume oxygen. Respirometry experiments allowed us to estimate higher oxygen uptake rates in wastewater than in the waters of the Gironde Estuary. Finally, the analysis of 7-yr data series from the continuous monitoring of the physico-chemical water quality (MAGEST network: MArel Gironde ESTuary) highlights periods of hypoxia in the upstream section of the estuary during pronounced low water around the Bordeaux conurbation. Statistical treatments of the 7-yr time series of DO concentration demonstrate the significant impact of the Bordeaux metropolitan area as it appears that the under-oxygenations increase during marked low water, in the presence of the TMZ, when the water temperature is high, and where the dissolved oxygen content is already low and can be quickly consumed after untreated storm water discharges. This study also shows that the nature of biological treatment used by the WWTPs and the temporary storage capacity of storm water have a critical role in the release of such compounds into the environment. This work finally provides strategies for effluent discharges to water managers, to short and medium terms, based on hydrological and physico-chemical conditions of the environment in order to limit their impact on the water oxygenation of the Garonne River.

Objetivo. Examinar a pertinência de utilização de abordagem multicritério como ferramenta de planejamento em reúso de água. Metodologia. As etapas são: (1) levantamento bibliográfico; (2) caracterização do Distrito Federal (área de estudo); (3) definir as áreas passíveis de serem irrigadas com água de reúso por sobreposição de mapas temáticos; (4) trabalho com decisores; (5) utilização do Método ELECTRE III; (6) apresentar e discutir resultados; (7) avaliar o trabalho desenvolvido. Resultados: (1) Os esgotos sanitários tratados de todas as estações de tratamento de esgotos (ETEs) não apresentaram qualidade satisfatória para irrigação irrestrita. Sugere-se seu uso na irrigação das grandes culturas do Distrito Federal (DF): milho, soja, café e trigo; (2) identificaram-se seis alternativas relacionadas às ETEs para se realizar reúso no Distrito Federal: Brazlândia, Samambaia/Melchior, Gama, Sul, Planaltina e São Sebastião; (3) as seis alternativas têm capacidade para irrigar todos os canteiros ornamentais, como também 4.268 ha de áreas agrícolas - correspondentes a 38% das áreas irrigadas das grandes culturas do DF; (4) Após a aplicação do Método ELECTRE III, as alternativas mais vantajosas relacionaram-se às ETEs Sul e Samambaia/Melchior. Conclusões: (1) a implementação do reúso de água no DF deve ser considerada no gerenciamento dos recursos hídricos; (2) a abordagem multicritério mostrou-se ferramenta apropriada ao planejamento em reúso de água; (3) o Método ELECTRE III adequou-se ao problema e foi sensível às preferências dos decisores. / Objective. To examine the relevance of adopting the multi-criterion approach as a planning tool when water is reused. Methods. It consisted of the following stages: (1) a bibliographical survey; (2) description of the Federal District (area under study); (3) determining the areas liable to irrigation with reused water by overlaying thematic maps: (4) working with decision makers; (5) applying the ELECTRE III Method; (6) presenting and discussing results; (7) assessing the work undertaken. Results: (1)The quality of the sewage treated in all the wastewater treatment plants (WTPs) was found to be unsuitable for unrestricted irrigation. It was suggested that it be reused in irrigating the Federal District´s major crops: maize, soy bean, coffee and wheat; (2) six alternatives, with regard to wastewater treatment plants, were identified for undertaking water reuse in the Federal District: Brazlândia, Samambaia/Melchior, Gama, Sul, Planaltina and São Sebastião; (3) the six alternatives are capable of irrigating all public flower beds, as well as 4,268 hectares of farmland - representing 38% of the Federal District´s irrigated lands under major crop cultivation; (4) after applying the ELECTRE III Method, the most advantageous alternatives were those related to Sul and Samambaia/Melchior wastewater treatment plants. Conclusions: (1) water reuse should be considered in water resources management in the Federal District; (2) the multi-criterion approach proved to be a suitable tool when planning water reuse; (3) the ELECTRE III Method was a suitable solution to the problem and met the requirements of the decision makers.

Objetivo. Examinar a pertinência de utilização de abordagem multicritério como ferramenta de planejamento em reúso de água. Metodologia. As etapas são: (1) levantamento bibliográfico; (2) caracterização do Distrito Federal (área de estudo); (3) definir as áreas passíveis de serem irrigadas com água de reúso por sobreposição de mapas temáticos; (4) trabalho com decisores; (5) utilização do Método ELECTRE III; (6) apresentar e discutir resultados; (7) avaliar o trabalho desenvolvido. Resultados: (1) Os esgotos sanitários tratados de todas as estações de tratamento de esgotos (ETEs) não apresentaram qualidade satisfatória para irrigação irrestrita. Sugere-se seu uso na irrigação das grandes culturas do Distrito Federal (DF): milho, soja, café e trigo; (2) identificaram-se seis alternativas relacionadas às ETEs para se realizar reúso no Distrito Federal: Brazlândia, Samambaia/Melchior, Gama, Sul, Planaltina e São Sebastião; (3) as seis alternativas têm capacidade para irrigar todos os canteiros ornamentais, como também 4.268 ha de áreas agrícolas - correspondentes a 38% das áreas irrigadas das grandes culturas do DF; (4) Após a aplicação do Método ELECTRE III, as alternativas mais vantajosas relacionaram-se às ETEs Sul e Samambaia/Melchior. Conclusões: (1) a implementação do reúso de água no DF deve ser considerada no gerenciamento dos recursos hídricos; (2) a abordagem multicritério mostrou-se ferramenta apropriada ao planejamento em reúso de água; (3) o Método ELECTRE III adequou-se ao problema e foi sensível às preferências dos decisores. / Objective. To examine the relevance of adopting the multi-criterion approach as a planning tool when water is reused. Methods. It consisted of the following stages: (1) a bibliographical survey; (2) description of the Federal District (area under study); (3) determining the areas liable to irrigation with reused water by overlaying thematic maps: (4) working with decision makers; (5) applying the ELECTRE III Method; (6) presenting and discussing results; (7) assessing the work undertaken. Results: (1)The quality of the sewage treated in all the wastewater treatment plants (WTPs) was found to be unsuitable for unrestricted irrigation. It was suggested that it be reused in irrigating the Federal District´s major crops: maize, soy bean, coffee and wheat; (2) six alternatives, with regard to wastewater treatment plants, were identified for undertaking water reuse in the Federal District: Brazlândia, Samambaia/Melchior, Gama, Sul, Planaltina and São Sebastião; (3) the six alternatives are capable of irrigating all public flower beds, as well as 4,268 hectares of farmland - representing 38% of the Federal District´s irrigated lands under major crop cultivation; (4) after applying the ELECTRE III Method, the most advantageous alternatives were those related to Sul and Samambaia/Melchior wastewater treatment plants. Conclusions: (1) water reuse should be considered in water resources management in the Federal District; (2) the multi-criterion approach proved to be a suitable tool when planning water reuse; (3) the ELECTRE III Method was a suitable solution to the problem and met the requirements of the decision makers.

<p></p><p></p><p></p><p>In urbanized river basins, sanitary wastewater and urban runoff (non-sanitary water) from urban agglomerations drain to complex engineered networks, are treated at centralized wastewater treatment plants (WWTPs) and discharged to river networks. Discharge from multiple WWTPs distributed in urbanized river basins contributes to impairments of river water-quality and aquatic ecosystem integrity. The size and location of WWTPs are determined by spatial patterns of population in urban agglomerations within a river basin. Economic and engineering constraints determine the combination of wastewater treatment technologies used to meet required environmental regulatory standards for treated wastewater discharged to river networks. Thus, it is necessary to understand the natural-human-engineered networks as coupled systems, to characterize their interrelations, and to understand emergent spatiotemporal patterns and scaling of geochemical and ecological responses. </p><br><p></p><p></p><p>My PhD research involved data-model synthesis, using publicly available data and application of well-established network analysis/modeling synthesis approaches. I present the scope and specific subjects of my PhD project by employing the <i>Drivers-Pressures-Status-Impacts-Responses</i> (<i>DPSIR</i>) framework. The defined research scope is organized as three main themes: (1) River network and urban drainage networks (<i>Foundation</i>-<i>Pathway of Pressures</i>); (2) River network, human population, and WWTPs (<i>Foundation</i>-<i>Drivers</i>-<i>Pathway of Pressures</i>); and (3) Nutrient loads and their impacts at reach- and basin-scales (<i>Pressures</i>-<i>Impacts</i>).</p><br><p></p><p></p><p>Three inter-related research topics are: (1) the similarities and differences in scaling and topology of engineered urban drainage networks (UDNs) in two cities, and UDN evolution over decades; (2) the scaling and spatial organization of three attributes: human population (POP), population equivalents (PE; the aggregated population served by each WWTP), and the number/sizes of WWTPs using geo-referenced data for WWTPs in three large urbanized basins in Germany; and (3) the scaling of nutrient loads (P and N) discharged from ~845 WWTPs (five class-sizes) in urbanized Weser River basin in Germany, and likely water-quality impacts from point- and diffuse- nutrient sources. </p><br><p></p><p></p><p>I investigate the UDN scaling using two power-law scaling characteristics widely employed for river networks: (1) Hack’s law (length-area power-law relationship), and (2) exceedance probability distribution of upstream contributing area. For the smallest UDNs, length-area scales linearly, but power-law scaling emerges as the UDNs grow. While area-exceedance plots for river networks are abruptly truncated, those for UDNs display exponential tempering. The tempering parameter decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power-law exponent for mature UDNs tends to be larger than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and non-random branching.</p><br><p></p><p></p><p>In this study, I also examine the spatial patterns of POP, PE, and WWTPs from two perspectives by employing fractal river networks as structural platforms: spatial hierarchy (stream order) and patterns along longitudinal flow paths (width function). I propose three dimensionless scaling indices to quantify: (1) human settlement preferences by stream order, (2) non-sanitary flow contribution to total wastewater treated at WWTPs, and (3) degree of centralization in WWTPs locations. I select as case studies three large urbanized river basins (Weser, Elbe, and Rhine), home to about 70% of the population in Germany. Across the three river basins, the study shows scale-invariant distributions for each of the three attributes with stream order, quantified using extended Horton scaling ratios; a weak downstream clustering of POP in the three basins. Variations in PE clustering among different class-sizes of WWTPs reflect the size, number, and locations of urban agglomerations in these catchments. <b></b></p><br><p></p><p></p><p>WWTP effluents have impacts on hydrologic attributes and water quality of receiving river bodies at the reach- and basin-scales. I analyze the adverse impacts of WWTP discharges for the Weser River basin (Germany), at two steady river discharge conditions (median flow; low-flow). This study shows that significant variability in treated wastewater discharge within and among different five class-sizes WWTPs, and variability of river discharge within the stream order <3, contribute to large variations in capacity to dilute WWTP nutrient loads. For the median flow, reach-scale water quality impairment assessed by nutrient concentration is likely at 136 (~16%) locations for P and 15 locations (~2%) for N. About 90% of the impaired locations are the stream order < 3. At basin-scale analysis, considering in stream uptake resulted 225 (~27%) P-impaired streams, which was ~5% reduction from considering only dilution. This result suggests the dominant role of dilution in the Weser River basin. Under the low flow conditions, water quality impaired locations are likely double than the median flow status for the analyses. This study for the Weser River basin reveals that the role of in-stream uptake diminishes along the flow paths, while dilution in larger streams (4≤ stream order ≤7) minimizes the impact of WWTP loads. </p><br><p></p><p></p><p>Furthermore, I investigate eutrophication risk from spatially heterogeneous diffuse- and point-source P loads in the Weser River basin, using the basin-scale network model with in-stream losses (nutrient uptake).Considering long-term shifts in P loads for three representative periods, my analysis shows that P loads from diffuse-sources, mainly from agricultural areas, played a dominant role in contributing to eutrophication risk since 2000s, because of ~87% reduction of point-source P loads compared to 1980s through the implementation of the EU WFD. Nevertheless, point-sources discharged to smaller streams (stream order < 3) pose amplification effects on water quality impairment, consistent with the reach-scale analyses only for WWTPs effluents. Comparing to the long-term water quality monitoring data, I demonstrate that point-sources loads are the primary contributors for eutrophication in smaller streams, whereas diffuse-source loads mainly from agricultural areas address eutrophication in larger streams. The results are reflective of spatial patterns of WWTPs and land cover in the Weser River basin.</p><br><p></p><p></p><p>Through data-model synthesis, I identify the characteristics of the coupled natural (rivers) – humans – engineered (urban drainage infrastructure) systems (CNHES), inspired by analogy, coexistence, and causality across the coupled networks in urbanized river basins. The quantitative measures and the basin-scale network model presented in my PhD project could extend to other large urbanized basins for better understanding the spatial distribution patterns of the CNHES and the resultant impacts on river water-quality impairment.</p><p><br></p><p></p>

The wastewater treatment process is one of the most important processes which contributes to the protection of the environment. This process can also potentially recover necessary and scarce raw materials, such as phosphorus. Research of the wastewater treatment technology is an increasingly relevant topic and more innovative knowledge should be gradually implemented into existing plants. However, the implementation of such technology involves increased investment and often operating costs. This is, why there is a growing interest in improving the energy intensity and hydraulic efficiency of the installed wastewater plant machinery. The optimization of operating parameters in such machinery can also bring significant savings, which can be potentially re-invested into other technologies. This work deals with the issue of proper evaluation of installed machinery for the selection of operating parameters and assessment of their significance. As the challenge, wastewater treatment technology is very sensitive towards the combination of technological equipment and incorrect operational parameters can lead to erroneous evaluation of the efficiency of individual equipment or inappropriate engineering proposals. To eliminate these risks, an analytical procedure for the selection and evaluation of parameters is proposed in this work. This procedure is demonstrated on six types of equipment. To verify the conclusions of the proposed procedure, a model design of the equipment was performed, in which the influence of individual parameters was concisely assessed. By using the data, the proposed procedure could be validated more specifically. In this work, the necessary data for the design was obtained by experimental research and extensive testing. The results confirm the practical applicability of the proposed procedure.

L'explosion démographique a conduit à une augmentation intensive des contaminants environnementaux issus de différentes émissions anthropiques, par exemple, les hydrocarbures de pétrole, les pesticides, les biphényles polychlorés (BPC) ainsi que d’autres déchets ménagers tels que les détergents utilisés comme nettoyants ménagers. Du fait de leur persistance et du point de vue toxicologique, les résidus de ces contaminants organiques, qui peuvent être détectés dans les différentes matrices environnementales (eau, sédiments, air et biotes), parfois à très faible concentration (micropolluants), ont conquis l'attention du public. Cette étude vise à déterminer les niveaux de concentration de contaminants sélectionnés dans les sédiments de surface et à identifier la source de ces produits chimiques dans le ruisseau Cortiou. Les résultats ont montré une forte contamination par les hydrocarbures dans la zone étudiée. De plus, ces résultats ont probablement reflété le fait que les processus de biodégradation se sont produits parallèlement à une répartition chronique des charges d’épuration non traitées. Ces polluants organiques ont également confirmé un effet néfaste sur le biote marin et plus particulièrement sur les communautés benthiques pour certaines stations / Demographic explosion has led to increase intensively environmental contaminants issued from different anthropogenic release e.g. petroleum hydrocarbons, pesticides, polychlorinated biphenyls (PCBs) and also other domestic waste such as detergents as household cleaner. Due to their persistence and the toxicological point of view, the remnants of these organic contaminants, which can be detected in the different environmental matrices (water, sediment, air and biota), sometimes with very low concentration (micropollutants), has gained the public attention. This study aims to determine the concentration levels of selected contaminants in surficial sediments and identifying the source of these chemicals in Cortiou Creek. The results showed high contamination by hydrocarbons in the studied area. Additionally, these results probably reflected that biodegradation processes occurred concomitantly with a chronic apportionment of untreated sewage loading. These organic pollutants also confirmed an adverse effect for marine biota and more particularly for benthic communities for some stations

[ES] Los procesos convencionales de depuración del agua residual presentan un elevado consumo energético y no permiten la recuperación de los recursos presentes en el agua. En la transformación de las Estaciones Depuradoras de Agua Residual (EDAR) en estaciones de recuperación de recursos, los procesos de redirección de carbono, como la ultrafiltración del agua residual (UF), juegan un papel crucial. Esta tecnología envía toda la materia orgánica suspendida y parte de la soluble a la digestión anaerobia. Tras la filtración, la línea principal de aguas presenta una composición diferente a la tradicional, principalmente una baja ratio de materia orgánica por unidad de nitrógeno (DQO/N) ausencia de sólidos suspendidos. Esta tesis doctoral tiene como objetivo estudiar experimentalmente, y con modelos matemáticos, diferentes alternativas de tratamiento del permeado de una planta piloto de UF de agua residual urbana real para lograr un efluente que cumpla con los requisitos de vertido. Los esquemas propuestos permiten aprovechar las infraestructuras existentes de las EDARs. La tesis está estructurada en cuatro bloques: 1- Estudio proceso convencional de nitrificación-desnitrificación (ND). Los resultados indican que el proceso de filtración retiene una elevada concentración de materia orgánica y reduce la ratio DQO/N por debajo de las condiciones estequiométricas necesarias, provocando que no todo el nitrógeno pueda ser eliminado mediante ND. Para poder mantener este tratamiento se necesitaría baipasear una parte del agua de entrada al proceso de filtración, para ajustar la ratio DQO/N al valor necesario, o aplicar esta alternativa en aquellos influentes con una alta concentración de materia orgánica soluble, ya que una parte de esta fracción no será retenida. 2- Evaluación del proceso de nitrificación parcial (NP) seguido del proceso Anammox. Ambas etapas biológicas no requieren de materia orgánica para la eliminación del nitrógeno y su consumo energético es menor, al reducir las necesidades de aireación. Experimentalmente se estudió el proceso de NP en la línea principal de aguas. Regulando la duración de la fase aerobia mediante un controlador basado en el pH y el oxígeno, mantenido una concentración de oxígeno de 0.5 mg O2/L y tiempos de retención celular de 3 a 10 días, se consiguió acumular N-NO2 en el reactor. El modelo matemático confirmó la importancia de estos parámetros de operación. 3- Concentración del nitrógeno mediante columnas de intercambio catiónico (IC) y recuperación en contactores de membranas (HFMC). Inicialmente se seleccionó el material adsorbente a partir de los resultados de los ensayos de cinéticas de adsorción. La zeolita natural, el material escogido, se caracterizó y se analizó la influencia de los interferentes mediante las isotermas de adsorción. También se analizó qué regenerante ofrecía mejores resultados. Por último, se realizaron varios ensayos en columnas de adsorción para estudiar la influencia del caudal de trabajo y la concentración de amonio en el afluente sobre la capacidad de adsorción de amonio y el volumen de permeado tratado antes de alcanzar el punto de ruptura. Así mismo se ha estudiado el efecto del caudal de regeneración y la concentración del agente regenerante sobre la capacidad de regeneración y la concentración de la corriente rica en nitrógeno. Se observó cómo con la medida de la conductividad es posible determinar la duración de ambas fases. Los datos experimentales, los resultados de los modelos matemáticos y un balance económico sirvieron para determinar las condiciones de operación. 4- Análisis económico y ambiental de las tres alternativas propuestas para identificar las alternativas viables en la mejora de una EDAR existente o construcción de una nueva instalación. En ambos escenarios el proceso de UF resultó ser el principal limitante para la implantación de alguna de las alternativas. Realizando una proyección futura sobre cómo estará esta tecnología en un corto plazo se est / [CA] Els processos convencionals de depuració de l'aigua residual presenten un elevat consum energètic i no permeten una recuperació dels recursos presents en l'aigua. En la transformació de les Estacions Depuradores d'Aigua Residual (EDAR) en estacions de recuperació de recursos, els processos de redirecció de carboni, com la ultrafiltració de l'aigua residual (UF) juguen un paper crucial. Aquesta tecnologia envia tota la matèria orgànica suspesa i part de la soluble (la fracció col·loidal) a la digestió anaeròbia. Després de la filtració, la línia principal d'aigües presenta una composició diferent de la tradicional, un baix ràtio de matèria orgànica per unitat de nitrogen (DQO/N) i està exempt de sòlids suspesos. Aquesta tesi doctoral té com a objectiu estudiar experimentalment, i amb models matemàtics, diferents alternatives de tractament del permeat d'una planta pilot d'ultrafiltració d'aigua residual urbana real per a aconseguir un efluent que complisca amb els requisits d'abocament. Els esquemes proposats permeten aprofitar les infraestructures existents de les EDARs. La tesi està estructurada en quatre blocs: 1- Estudi del procés convencional de nitrificació-desnitrificació (ND). Els resultats experimentals indiquen que el procés de filtració reté una elevada concentració de matèria orgànica i redueix el ràtio el ràtio DQO/N per baix de les condicions estequiomètriques necessàries, que no tot el nitrogen puga ser eliminat amb ND. Pel que per a poder mantindre aquest tractament es necessitari bypasear una part de l'aigua d'entrada el procés de filtració que parteix de l'aigua d'entrada per a ajustar el ràtio DQO/N al valor necessari, o aplicar-lo en aquells influents amb una alta concentració de matèria orgànica soluble, ja que una part d'aquesta fracció no serà retinguda. 2- Avaluació del procés de nitrificació parcial (NP) seguit del procés Anammox. Totes dues etapes biològiques no requereixen de matèria orgànica per a l'eliminació del nitrogen i el seu consum energètic és menor, en reduir les necessitats de ventilació. Experimentalment es va estudiar el procés de NP en la línia principal d'aigües.Reglant la duració de la fase aeròbia mitjançant un controlador basat en el pH i l'oxigen, mantingut una concentració d'oxigen de 0.5 mg O2/L i temps de retenció cel·lular de 3 a 10 dies, es va aconseguir acumular NO2 en el reactor. El model matemàtic va confirmar la importància d'aquests paràmetres d'operació. 3- Concentració del nitrogen mitjançant columnes d'intercanvi catiònic (IC) i recuperació en contactors de membranes (HFMC). Inicialment es va seleccionar el material adsorbent a partir dels resultats de les proves de cinètiques d'adsorció. La zeolita natural, el material triat, es va caracteritzar i es va analitzar la influència dels interferents mitjançant isotermes d'adsorció. També es va analitzar quin regenerant oferia millors resultats. Després, es van realitzar diversos assajos en columnes d'adsorció per a estudiar la influència del cabal de treball i la concentració d'amoni en el influent i d'altra banda, el cabal de regeneració i la concentració de l'agent regenerant. Es va observar com mitjançant amb la conductivitat es pot determinar la duració de totes dues fases. Les dades experimentals, els resultats dels models matemàtics i un balanç econòmic van servir per a determinar les condicions d'operació. 4- Anàlisi econòmica i ambiental de les tres alternatives proposades, amb consideracions ambientals per a identificar les alternatives viables en la millora d'una EDAR existent o construcció d'una nova instal·lació. En tots dos escenaris el procés de UF va resultar ser el principal coll de botella per a facilitar la implantació d'alguna de les alternatives. Realitzant una projecció futura sobre com estarà aquesta tecnologia en un curt termini, es van estimar unes moderades millores tant en el seu cost, operació i rendiment. En aquesta projecció futura l'escenari 1, ND, no aconsegueix aconseguir uns re / [EN] Conventional wastewater treatment processes are energy-intensive and do not allow the recovery of the resources present in the water. On the way towards the transformation of Wastewater Treatment Plants (WWTP) into resource recovery plants, carbon redirection processes, such as ultrafiltration of wastewater (UF), play a crucial role. This technology sends all suspended and part of the soluble organic matter to anaerobic digestion. After filtration, the main water line presents a different characteristic from the traditional one, mainly a low ratio of organic matter per unit of nitrogen (COD/N) and absence of suspended solids. This doctoral thesis aims to study experimentally, and with mathematical models, different alternatives of treatment of the permeate from a real urban wastewater UF pilot plant to achieve an effluent that meets the discharge requirements. The proposed schemes allow to take advantage of existing WWTP infrastructures. The thesis is structured in four blocks: 1- Study of conventional nitrification-denitrification (ND) process. The results indicate that the filtration process retains a high concentration of organic matter and reduces the COD/N ratio below the necessary stoichiometric conditions, causing incomplete nitrogen removal. In order to maintain this treatment, it would be necessary to bypass part of the inlet water to the filtration process, to adjust the COD/N ratio to the necessary value, or to apply this alternative in those influents with a high concentration of soluble organic matter, since part of this fraction will not be retained. 2- Evaluation of the partial nitrification process (PN) followed by the Anammox process. Both biological stages do not require organic matter for nitrogen removal and their energy consumption is lower, as aeration needs are reduced. The PN process was studied experimentally in the main water line. By controlling the duration of the aerobic phase with a pH and oxygen-based controller, maintaining an oxygen concentration of 0.5 mg O2/L and sludge retention times of 3 to 10 days, N-NO2 accumulation in the reactor was achieved. The mathematical model confirmed the importance of these operational parameters. 3- Nitrogen concentration by cation exchange columns (CEC) and recovery in membrane contactors (HFMC). Initially, the adsorbent material was selected based on the results of the adsorption kinetics tests. Natural zeolite, the material chosen, was characterized and the influence of interferents was analyzed by means of adsorption isotherms. It was also analyzed which regenerant provided the best results. Finally, several tests were carried out on adsorption columns to study the influence of the working flow rate and the concentration of ammonium in the influent on the ammonium adsorption capacity and the volume of permeate treated before reaching the breakpoint. The effect of the regeneration flow rate and the concentration of the regeneration agent on the regeneration capacity and the concentration of the nitrogen-rich stream was also studied. It was observed that by conductivity monitoring it is possible to determine the duration of both phases. Experimental data, the results of mathematical models and an economic balance were used to determine the operating conditions. 4- Economic and environmental analysis of the three proposed alternatives to identify viable alternatives in the improvement of an existing WWTP or construction of a new facility. In both scenarios the UF process turned out to be the main bottleneck to facilitate the implementation of any of the alternatives. By making a future projection of how this technology will be in the short term, improvements in its acquisition cost, operating costs and performance were estimated. With this projection, alternative 1, ND, does not achieve appropriate economic returns. Alternative 2, PN + Anammox, shows a better economic balance than the current situation. Alternative 3, CEC + HFMC, as it does not take advanta / Esta tesis se ha desarrollado dentro del marco de trabajo del proyecto ‘Aplicación de la tecnología de membranas para potenciar la transformación de las EDAR actuales en estaciones de recuperación de recursos Proyecto MEM4REC (Código del proyecto: CTM2017-86751-C2-1-R), financiado por el Ministerio de economía, industria y competitividad (MINECO). También esta tesis se ha visto financiada por la ayuda para la formación de profesorado universitario (FPU) (código de la ayuda: FPU17/00540), financiada por el Ministerio de Universidades / Godifredo Calvo, J. (2024). Estudio de la eliminación/recuperación de nitrógeno en el permeado de la ultrafiltración de la línea de aguas de una EDAR mediante eliminación por nitrificación parcial y recuperación con zeolitas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203439

The activated sludge and anaerobic digestion processes have been modelled in widely accepted models. Nevertheless, these models still have limitations when describing operational problems of microbiological origin. The aim of this thesis is to develop a knowledge-based model to simulate risk of plant-wide operational problems of microbiological origin.For the risk model heuristic knowledge from experts and literature was implemented in a rule-based system. Using fuzzy logic, the system can infer a risk index for the main operational problems of microbiological origin (i.e. filamentous bulking, biological foaming, rising sludge and deflocculation). To show the results of the risk model, it was implemented in the Benchmark Simulation Models. This allowed to study the risk model's response in different scenarios and control strategies. The risk model has shown to be really useful providing a third criterion to evaluate control strategies apart from the economical and environmental criteria. / Els processos de fangs activats i digestió anaeròbia estan descrits en models àmpliament acceptats. No obstant, aquests encara tenen limitacions a l'hora de descriure problemes operacionals d'origen microbiològic. L'objectiu és desenvolupar un model basat en el coneixement per simular el risc de problemes operacionals d'origen microbiològic en planta completa. Per al model de risc es va utilitzar coneixement d'experts i de la bibliografia implementat després en un sistema basat en regles. Utilitzant la lògica difusa, el sistema pot inferir un índex de risc per a problemes operacionals d'origen microbiològic (esponjament, escumes, desnitrificació incontrolada i desflocul•lació). Per a mostrar els resultats del model de risc es va implementar i aplicar en els diferents Benchmark Simulation Models. Això ha permés estudiar la resposta del model de risc en diferents escenaris i estratègies de control. El model de risc ha mostrat ser molt útil proporcionant un tercer criteri per a l'avaluació d'estratègies de control a part dels criteris econòmics i ambientals.

Volatile Organic Compounds (VOCs) are one of the main groups of odour causing compounds in Waste Water Treatment Plants (WWTP). Adsorption technology is already established, in recent years the interest for the optimization of the costs associated with this technique has grown significantly. In particular, there are different options, from the use of low cost adsorbents, to reducing costs associated with carbon regeneration process. In this thesis, the adsorption of the three VOCs on sewage sludge based adsorbents was studied. It was proved that adsorbents obtained by chemical activation of sewage sludge with alkaline hydroxides are comparable to commercial activated carbons (ACs). Likewise, the adsorption of multicomponent gaseous streams was also studied. Related to the ACs regeneration, it was proposed a regeneration treatment of VOC saturated ACs with H2O2 based on advanced oxidation processes (AOP). The influence of the surface chemistry of ACs in this regeneration process was also studied. / Los compuestos orgánicos volátiles (COVs) son unos de los principales compuestos causantes de olores en las emisiones de EDARs. La adsorción es una técnica ampliamente utilizada para la eliminación de COVs en corrientes gaseosas y en los últimos tiempos ha crecido significativamente el interés para la optimización de los costes relacionados con esta técnica. En esta tesis se estudió el proceso de adsorción tres COVs en adsorbentes preparados a partir de lodos de EDAR, comprobando que adsorbentes obtenidos mediante activación química de lodos de depuradora son comparables a carbones activados comerciales (CAs). También se estudió la adsorción de corrientes multicomponente de COVs. En referencia a la regeneración del carbón activado, se propuso un tratamiento de regeneración con H2O2 de CAs saturados con COVs basado en los procesos avanzados de oxidación. Asimismo se estudió la influencia de la química superficial de los CAs en el proceso de regeneración con H2O2.