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

South Africa is a water scarce country. The expansion of the industrial, mining, and agricultural sectors to meet the needs of South Africa’s growing population requires more water. There is therefore an urgent need to develop effective wastewater treatment processes in order to recover and reuse water. This dissertation presents the treatment of an acidic wastewater stream from a platinum refinery which at present is being disposed of by contract with a waste disposal company. The major concern in treating the acid effluent stream is the high concentration of sodium ions (18 200 mg/l) and chloride ions (104 900 mg/l). The precipitation process is used to treat wastewater, but ultimately it generates more secondary waste as a sludge. The other process that is used to treat wastewater is reverse osmosis (RO). RO is usually preferred in the last stage of the treatment because the process is more expensive as membranes need to be replaced regularly. The approach used in this research focuses on evaporating liquid, consequently concentrating the remaining solution until the ions in the solution crystallize. The liquid produced is recycled back into the platinum plant for reuse, and the remaining salt crystals are collected as the useful product. The proposed water treatment process produces dilute hydrochloric acid as the condensate and a crystallized sodium chloride rich residue. The refinery is currently disposing of around 20 000 l/day of wastewater to landfills. The proposed treatment process can recover half of the volume of the wastewater stream to the refinery, helping reduce the fresh water consumption of the process by 10 000 l/day. Furthermore, this will reduce the volume of wastewater going to disposal by a half, namely only 10 000 l/day will need to be disposed of. The amount of Cl that can be recovered is variable and depends on the quantity of chloride in the wastewater. In the two samples processed the recovery was between a 2,5 w% and 10,7 wt% aqueous HCl solution. This corresponds to a saving of between 250 to 1000 kg/day of HCl. As the concentration of the recovered solution is variable, the recycling process would need to monitor the composition of the recycled stream and make up the acid concentration to some fixed value for reuse in the prices. The production of a dilute hydrochloric acid stream should be particularly attractive to the platinum refinery as the operation of the refinery requires hydrochloric acid as a feed. Thus, by recycling the wastewater, the refinery would reduce the volume of wastewater to be disposed of thereby reducing the cost of disposal of the waste while simultaneously reducing the cost of buying fresh hydrochloric acid. The proposed recovery of liquid and recycling it back to the refinery, will also reduce the environmental impact of the refinery, and very importantly in a water scarce country, reduce the freshwater consumption of the process. / Physics / M. Sc. (Physics)

The Swedish water sector faces many challenges in terms of climate change, worn out facilities and distribution systems as many of them were built in the 50-, 60- and 70s, but also increased cyber security concerns. Collaborations between different actors are therefore required to address these challenges. This thesis work's purpose is to examine the opportunities a collaboration between water treatment plants could bring for the water sector to achieve a more sustainable drinking water production. The purpose is also to examine the most efficient way to establish a collaboration between them through digital means. A workshop and several interviews with representatives from different water treatment plants were conducted to gather information on possibilities of data/information sharing between them, but also to make a security classification of data/information generated at the water treatment plants. The representatives included process engineers, process technicians, security associates and an associate at Svenskt vatten, an interest organization for the water sector. The result showed that data/information sharing is already taking place in the sector under limited conditions. Smaller VA organizations have more challenges due to lack of skilled workers, partners and time. It is difficult for many in the sector to know where to turn to when in need of help, particularly for smaller VA organizations who usually are the ones with fewer contact networks. It is not to say that only smaller VA organizations are affected but they are more likely to lack contact with other water organizations. The majority of water treatment plants agree on that data/information on treatment processes would be allowed to share under limited conditions. The information classification is a matter for each plant due to different security realities which determines the information classification. This makes it difficult to decide on what parameters could be shared by every water treatment plant. This needs to be investigated further in order to determine what data/information could be shared by most water treatment plants on a platform. Most participants thought that a platform of some kind would be the best solution to simplify data/information sharing between water treatment plants. The suggested platform is a good start for making contacts between water treatment plants and has the potential to enable storage and sharing of data/information in the future. / Den svenska VA sektorn står inför många utmaningar så som klimatförändringar, slitna anläggningar och distributionsnät då många av dem byggdes under 50-, 60- och 70-talet. Även oron kring cybersäkerheten ökar. Samarbeten mellan olika aktörer krävs för att lösa dessa utmaningar. Syftet med examensarbetet är att undersöka de möjligheter som samarbeten mellan vattenverk skulle medföra för att nå en mer hållbar dricksvattenproduktion. Syftet är också att undersöka det mest effektiva sättet att få till ett samarbete mellan vattenverken med digitala medel. En workshop och flertalet intervjuer genomfördes med olika representanter från vattenverk för att samla information om möjligheten med att dela data/information mellan dem. Men också för att göra en säkerhetsklassning av data/information som genereras på vattenverken. Representanterna inkluderade processingenjörer, processtekniker, säkerhetsansvariga samt en medarbetare från Svenskt vatten, en intresseorganisation för vattensektorn. Resultatet visade att delning av data/information redan sker inom sektorn, dock under begränsade former. Mindre VA organisationer har fler utmaningar på grund av brist på anställda med rätt kompetens, samarbetspartners och tid. Många inom sektorn har utmaningar när det kommer till att söka och få hjälp, särskilt för de mindre VA organisationerna som vanligtvis har färre kontakter. Men de är inte bara de små som är påverkade av detta problem, men det är vanligare att de inte har kontakter med andra VA organisationer. De flesta vattenverken ansåg att data/information från reningssteg skulle vara möjligt att dela under begränsade former. Informationssäkerhetsklassning är en enskild fråga för varje vattenverk som baseras på de hot som varje vattenverk står inför. Detta medför att det är svårt att bestämma vilken data/information som kan delas av varje vattenverk. Detta område behöver vidare utredas innan ett beslut kan fattas om vilken data/information alla vattenverk ska dela på en plattform. De flesta deltagarna tyckte att en plattform av något slag skulle vara lösningen för att förenkla delning av data/information mellan vattenverken. Den föreslagna plattformen är en bra start för vattenverk att skapa kontakter och har potentialen att möjliggöra lagring och delning av data/information i framtiden.

[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

No / Sedimentation of non-homogeneous systems is the typical phenomenon indicating the physical instability as a key measure to the quality control of the preparation products. Currently, the determination methods for the sedimentation of non-homogeneous preparations are based on manual measurement or semi-quantitative observation, lacking of either automation or quantitative dynamic analysis. The purpose of this research was to realize automatic and quantitative monitoring of the sedimentation dynamics for non-homogenous systems as suspension, emulsions at laboratory level. Non-contact measurement method has been established to determine the sedimentation behaviors in a standard quartz tube for sedimentation, with internal diameter and height 23 mm and 215 mm, respectively, with controlled temperature and light intensity. As high performance camera has been equipped, the sedimentation images with high spatial and temporal resolution could be acquired, which can continuously capture sedimentation images with the resolution of 2048 x 2048 pixel at a maximum rate of 60 slides/s. All the pictures were processed to extract the luminance matrix top-down along the fixed vertical midline of each picture, which implied sedimentation characteristics of the system at the moment the picture was taken. Combining all the luminance matrixes along vertical middle lines of the pictures, a time-luminance matrix profile was obtained. Digital image processing techniques were used to eliminate interference and establish a three-dimensional surface model of the sedimentation dynamics. Then, the derivative mutation algorithm has been developed for the intelligent identification of sedimentation interface with threshold optimization so as to quantitatively analyze the sedimentation dynamics with visualization. The sedimentation curve and sedimentation dynamic equation of the non-homogeneous system were finally outputted by numerical fitting. The methodology was validated for great significance in determinations of small volume samples, parallel control multiple batches, and long period of time automatic measurement. (C) 2015 Elsevier B.V. All rights reserved.

An experimental study was carried out to evaluate the performance of pilot scale constructed wetlands for the treatment of domestic wastewater in Addis Ababa, Ethiopia. Three parallel sets of constructed wetlands; consisting of one Horizontal Flow (HF), one Vertical Flow (VF) and one hybrid of HF and VFconstructed in series were built in Addis Ababa. The wetland systems had identical wetland fill media and macrophytes but with different wastewater flow types. The total surface area of the wetland systems was 72 m2 /24 m2 for each/ and designed to treat 3.15 m3 of domestic wastewater per day. Triplicate grab samples were taken from the influent and effluents every 15 days for one year and analyzed within 24 hours. Temperature, pH, DO and EC were measured onsite and the nutrient content of macrophytes was determined twice during the monitoring period. During the first 12 months monitoring period, the average removal efficiencies of the HFCW, VFCW and hybrid CW were: BOD (89.1%, 92.2% and 93.4%), COD (80.6%, 82.1% and 84.0%), TSS (89.1, 83.8% and 84.7%), NH4 + (58.6%, 66.2% and 65.4%), NO3 - (64.0%, 71.5% and 73.5%), TN (49.1%, 54.9% and 58.7%), PO4 3- (45.4%, 50.3% and 48.4%), TP (58.0%, 51.7% and 54.4%) and FC (98.6%, 96.6% and 96.5%), respectively. The hybrid system showed relatively higher removal efficiencies for most pollutants. Again, the wetland systems showed relatively higher percent reduction during the dry seasons /from Dec - May/. The areal removal rate constants of BOD5, TN, PO4 3- and TP were higher than the literature values while the values of COD and TSS were lower compared to the literature values. Concerning the nutrient content of the wetland plant, the average TN contents of the below-ground and above-ground plant part were 1.56% and 2.27% for the HFCW, 1.75% and 2.74% for the VFCW and 1.80% and 2.63% for the hybrid system, respectively. Meanwhile, the average TP contents of the belowground and above-ground plant part were 0.139% and 0.064% for the HFCW, 0.167% and 0.067% for the VFCW and 0.115% and 0.065% for the hybrid systems, respectively. In general, the results showed that properly designed constructed wetland systems could be used as effective wastewater treatment method in Ethiopia. / Environmental Sciences / Ph. D. (Environmental Sciences)

Lau Wai Kee Albert. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2000-01, design report." / On double leaves. / Includes bibliographical references. / Chapter Chapter 1 --- Prologue --- p.1 / Definition of the unseen space --- p.2 / Unseen space in the city --- p.3 / Chapter Chapter 2 --- Justification of selected unseen space --- p.4 / Definition of nullah --- p.6 / Surface transformation of the nullah --- p.8 / People perception of the nullah --- p.10 / People perception of wastewater --- p.12 / Chapter Chapter 3 --- Justification of site selection --- p.15 / Site analysis --- p.18 / Transportation character --- p.22 / Chapter Chapter 4 --- Physical identity of nullah --- p.25 / Intrinsic meaning of nullah --- p.26 / Chapter Chapter 5 --- Philosophy of nullah --- p.30 / Concept --- p.34 / Project mission --- p.38 / Conceptual strategy --- p.39 / Chapter Chapter 7 --- Philosophical meaning of water --- p.46 / People perception to water --- p.50 / Basic concept in water space design --- p.52 / Chapter Chapter 8 --- Precedent study --- p.56 / Urban rivers --- p.57 / Local rivers --- p.66 / Chapter Chapter 9 --- Design ideas --- p.68 / Appendix / Water quality of Kai Tak nullah --- p.75 / Annual rainfall --- p.76 / "Interview with Dr. Chung, Dept. of Biology, CUHK" --- p.78 / Biblography --- p.80

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.