Thèses : « WASTEWATER TREATMENT MODELLING »

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Thomas, David N. « Flocculation modelling in wastewater treatment ». Thesis, Cranfield University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323835.

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Ghavipanjeh, Farideh. « Modelling and control of wastewater treatment ». Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250027.

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Samsó, Campà Roger. « Numerical modelling of constructed wetlands for wastewater treatment ». Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/144624.

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Constructed Wetlands (CWs) are a wastewater treatment technology that inherits the purification potential of natural wetlands and optimizes it to comply with regulations for treated discharges. CWs have become an equally performing alternative to conventional wastewater treatment technologies of communities up to 2000PE, with lower energy and maintenance costs. Despite their potential, CWs lack reliability, which holds back their full deployment in the territory. This fact results from the lack of understanding on their internal functioning and because they are prone to clogging. The enormous diversity of CWs typologies and operation strategies, and the fact that they operate at the mercy of the environmental conditions, makes each CW unique on its kind, and experimental studies are usually only representative of the studied system. This fact makes mathematical models essential to study their functioning. Several models for CWs have proliferated in the last dozen years to provide supporting tools for their design and operation as well as more insight into the treatment processes. However, compared to models utilized in similar disciplines, CWs models are still in an embrionary stage. Accordingly, the objectives of the current work were to develop a CWs model able to describe the most common processes taking place within CWs, and to use this model to shed light on the internal functioning of these systems in the long-term. The model, named BIO_PORE, was built in COMSOL Multiphysics and can simulate subsurface flow and pollutants transport in porous media. It also implements the biokinetic model Constructed Wetlands Model number 1 (CWM1) to describe the fate of organic matter, nitrogen and sulphur and the growth of the bacterial groups found in CWs. The model was calibrated with experimental data of a year of operation of a pilot system. Two empirical parameters (Mcap and Mbio_max ) were used to improve the description of bacterial growth obtained with CWM1 and to include the effects of solids accumulation on bacterial communities. The effect of these two parameters was evaluated using local sensitivity analysis. The model was later used to unveil the dynamics of bacterial communities within CWs. In addition, a theory was derived from simulation results, which aimed at describing the most basic functioning patterns of CWs based on the interaction between bacterial communities and accumulated solids. At the end of the document a mathematical formulation is presented to describe bioclogging and a numerical experiment is carried out to showcase its impact on simulation results. The main outcome of the current work was the BIO_PORE model. This model was able to reproduce effluent pollutant concentrations measured during an entire year of operation of the pilot system. Parameters Mcap and Mbio_max proved essential to prevent unlimited bacterial growth predicted by CWM1 near the inlet sections of CWs. These two parameters were also responsible for the good fitting with experimental data. This was confirmed with the sensitivity analysis, which demonstrated that they have a major impact on the model predictions for effluent COD and ammonia and ammonium nitrogen. The theory derived from simulation results indicated that bacteria move towards the outlet with time, following the accumulation of inert solids from inlet to outlet. This result may prove that CWs life-span is limited, corresponding to the time after which bacterial communities are pushed as much towards the outlet that their total biomass is not able to provide effluents with acceptable quality. The inclusion of bioclogging was a requisite to reproduce the bacterial distribution and fluid flow and pollutants transport within CWs. More work on the BIO_PORE model is required and more experimental data is necessary to calibrate and validate its results.

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Solimeno, Alessandro. « Numerical modelling of microalgae systems for wastewater treatment ». Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/441737.

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Reactions and processes that occur in microalgae and bacteria systems are difficult to understand because most of them take place simultaneously and depend on many parameters such as temperature, solar radiation, nutrients availability (e.g. carbon and nitrogen) as well on certain inhibitory conditions (e.g excess of oxygen in the culture medium). In comparison with conventional wastewater treatment technologies, less is known about the physical, chemical and biochemical reactions and processes that occur in microalgae-bacteria treatment systems. The main outcome of the present PhD thesis was to develop a new integrated mechanistic model, named BIO_ALGAE, which includes crucial physical and biokinetic processes to simulate microalgae growth in different type of cultures, and most particularly in wastewater. The model was used to advance the understanding the inherent complexity of microalgae and bacteria interactions that occur in high rate algal ponds (HRAP) and photobioreactors.BIO_ALGAE model was mainly built by coupling the River Water Quality Model 1 (RWQM1) formulation and the modified ASM3 model, and was implemented in COMSOL MultiphysicsTM simulation platform. Inorganic carbon, as a limiting substrate for the growth of microalgae, is one of the major innovative features of BIO_ALGAE. Carbon is an essential resource for microalgae production. Moreover, temperature, photorespiration, pH dynamics, solar radiation, light attenuation and transfer of gases to the atmosphere are considered main limiting factors for microalgae growth. In a pragmatic approach to reduce the model¿s complexity in the initial stages of its development, it was decided to start by studying physical, chemical and biokinetic processes of microalgae alone, hence neglecting bacterial processes. Once calibrated the most uncertain parameters of the model, bacteria processes were added, and this gave place to the integral model BIO_ALGAE. This model was calibrated and validated with high quality experimental data from pilot raceway ponds over short-time scale and for long-term operation.The BIO_ALGAE model has proved to be an efficient tool to understand microalgae and bacteria interactions in wastewater treatment and to simulate the dynamics of different components in the ponds. The model was used to investigate the effect of environmental conditions and nutrients availability on microalgae growth and the different hydraulic retention time (HRT) operating strategies on the relative proportion of microalgae and bacteria and biomass production. Moreover, thanks to the model it was possible to optimize the performance of both HRAP and photobioreactor.
Las reacciones y los procesos que ocurren en sistemas mixtos de microalgas y bacterias son difíciles de entender ya que la mayoría de ellos tienen lugar simultáneamente y dependen de muchos parámetros tales como temperatura, radiación solar, disponibilidad de nutrientes (e.g. carbono y nitrógeno) así como ciertas condiciones inhibitorias (e.g. exceso de oxígeno en el medio de cultivo). En comparación con las tecnologías convencionales de tratamiento de aguas residuales, actualmente hay poco conocimiento de las reacciones físicas, químicas y bioquímicas y de los procesos que se producen en los sistemas de tratamiento de microalgas y bacterias. El objetivo principal de la presente tesis doctoral fue desarrollar un nuevo modelo mecanístico integrado, denominado BIO_ALGAE, que incluye procesos físicos y bioquinéticos cruciales para simular el crecimiento de microalgas en diferentes tipos de cultivos, principalmente en aguas residuales. El modelo se utilizó para comprender de una mejor forma las interacciones que se llevan a cabo entre microalgas y bacterias en lagunas de alta carga (LAC) y fotobiorreactores. El modelo BIO_ALGAE se construyó mediante el acoplamiento del River Water Quality Model 1 (RWQM1) y del modelo ASM3 modificado, y se implementó en la plataforma de simulación COMSOL MultiphysicsTM. El carbono inorgánico, utilizado como sustrato limitante para el crecimiento de microalgas, es una de las principales características innovadoras de BIO_ALGAE. Además, la temperatura, la fotorespiración, la dinámica del pH, la radiación solar, la atenuación de la luz y la transferencia de gases a la atmósfera se consideraron los principales factores limitantes del crecimiento de las microalgas. Para reducir la complejidad del modelo en las etapas iniciales de su desarrollo, se decidió empezar por estudiar los procesos físicos, químicos y bioquinéticos sólo de las microalgas, dejando de lado los procesos bacterianos. Una vez calibrados los parámetros más sensibles del modelo, se añadieron los procesos bacterianos, lo que dio lugar al modelo integral BIO_ALGAE. Este modelo fue calibrado y validado con datos experimentales de alta calidad procedentes de LAC operadas a corto y largo plazo. El modelo BIO_ALGAE ha demostrado ser una herramienta eficaz para entender las interacciones de microalgas y bacterias en el tratamiento de aguas residuales y simular la dinámica de diferentes componentes en las LAC. El modelo se utilizó para investigar el efecto de las condiciones ambientales y la disponibilidad de nutrientes en el crecimiento de microalgas. También se estudió el efecto del tiempo de retención hidráulica sobre la proporción relativa de microalgas-bacterias y la producción de biomasa. Gracias al modelo fue posible optimizar el rendimiento tanto de las lagunas de alta carga como del fotobiorreactor.

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Soteman, Sven Wilhelm. « Modelling material mass balances over wastewater treatment plants ». Doctoral thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/14070.

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Includes bibliographical references.
The overall objective of whole wastewater treatment plant (WWTP)modelling is to develop a COD (electron), carbon (C), nitrogen (N), phosphorus (P), alkilinity (proton), calcium (Ca), magnesium (Mg) and inorganic suspended solids (ISS) concentrations mass balances models for unit operations in municipal WWTPs. The development of such a model, for both steady state and dynamic simulation conditions, is an objective greater that this thesis project, however, it makes a number of significant steps towards it.

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Mattei, Maria Rosaria. « Mathematical modelling of multispecies biofilms for wastewater treatment ». Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1182/document.

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Cette thèse s'intéresse à l'application d'un modèle mathématique unidimensionnel de formation et de croissance de biofilms multi-espèces. Le modèle se compose d'un système d'équations non linéaires aux dérivées partielles hyperboliques, décrivant la croissance d'espèces microbiennes dans le biofilm, et un système d'équations semi-linéaires aux dérivées partielles paraboliques, qui régit la diffusion de substrat de la phase aqueuse vers la matrice du biofilm. L'ensemble conduit à un problème de valeur limite libre, essentiellement hyperbolique. Dans une première étude, l'analyse et la simulation de la phase initiale de croissance du biofilm ont été examinées. Le problème mathématique résultant a été discuté en utilisant la méthode des caractéristiques et le théorème du point fixe a été utilisé pour déterminer l'existence et l'unicité des solutions mathématiques. Un deuxième aspect de la thèse porte sur l'analyse et la prévision de la dynamique des populations microbienne dans plusieurs types biofilms pour le traitement des eaux usées. Le modèle a été appliqué pour simuler la compétition bactérienne et évaluer l'influence de la diffusion du substrat sur la stratification microbienne des biofilms multi-espèces, en incluant les bactéries nitrifiantes, Anammox et bactéries sulfato-réductrices. Dans les deux cas, la méthode des caractéristiques a été utilisée à des fins numériques et l'équation de conservation de masse joue un rôle crucial pour vérifier l'exactitude des simulations. Les résultats des simulations montrent que le modèle est en mesure d'évaluer correctement les effets des conditions limites qui s'exercent sur la concurrence bactérienne. Enfin, ce modèle a été étendu pour inclure le phénomène de colonisation microbienne. Le nouveau modèle est capable de prendre en compte l'invasion de nouvelles espèces en se basant sur un ensemble d'équations non linéaires aux dérivées partielles hyperboliques pour ce qui concerne le processus de croissance. De plus, le processus d'invasion biologique d'espèces nouvelles dans le biofilm a été modélisé par un système d'équations non linéaires aux dérivées partielles paraboliques. Ce modèle d'invasion a été appliqué avec succès pour simuler l'invasion des bactéries hétérotrophes dans les biofilms autotrophes
This dissertation relates to the applications of a one-dimensional mathematical model for multispecies biofilm formation and growth. The model consists of a system of nonlinear hyperbolic partial differential equations, describing the growth of microbial species in biofilms, and a system of semilinear parabolic partial differential equations, which governs substrate diffusion from the surrounding aqueous phase into the biofilm. Overall, this leads to a free boundary value problem, essentially hyperbolic. In a first study, the analysis and simulations of the initial phase of biofilm growth have been addressed. The resulting mathematical problem has been discussed by using the method of characteristics and the fixed-point theorem has been used to obtain existence, uniqueness and properties of solutions. A second aspect of the thesis deals with the analysis and prediction of population dynamics in multispecies biofilms for wastewater treatment. The model has been applied to simulate the bacterial competition and to evaluate the influence of substrate diffusion on microbial stratification for a nitrifying multispecies biofilm including Anammox bacteria and a sulfate-reducing biofilm. In both cases, the method of characteristics has been used for numerical purposes and the mass conservation equation plays a crucial role in checking the accuracy of simulations. The simulation results reveal that the model is able to evaluate properly the effects that boundary conditions exert on bacterial competition. Finally, the biofilm model has been extended to include the colonization phenomenon. The new model is able to take into account the invasion of new species diffusing from bulk liquid to biofilm, still based on a set of nonlinear hyperbolic partial differential equations for what concerns growth process. Indeed, the biological invasion process of new species into the biofilm has been modeled by a system of nonlinear parabolic partial differential equations. The invasion model has been successfully applied to simulate the invasion of heterotrophic bacteria in a constituted autotrophic biofilm and viceversa

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Janus, Tomasz. « Modelling and simulation of membrane bioreactors for wastewater treatment ». Thesis, De Montfort University, 2013. http://hdl.handle.net/2086/9507.

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The work presented in this thesis leads to the formulation of a dynamic mathematical model of an immersed membrane bioreactor (iMBR) for wastewater treatment. This thesis is organised into three parts, each one describing a different set of tasks associated with model development and simulation. In the first part, the Author qualitatively and quantitatively compares various published activated sludge models, i.e. models of biochemical processes associated with bacterial growth, decay, lysis and substrate utilisation in activated sludge systems. As the thesis is focused on modelling membrane bioreactors (MBRs) which are known to experience membrane fouling as a result of adsorption of biopolymers present in the bulk liquid onto and within the membrane, all activated sludge models considered in this thesis are able to predict, with various levels of accuracy, the concentrations of biopolymeric substances, namely soluble microbial products (SMP) and extracellular polymeric substances (EPS). Some of the published activated sludge models dedicated to modelling SMP and EPS kinetics in MBR systems were unable to predict the SMP and EPS concentrations with adequate levels of accuracy, without compromising the predictions of other sludge and wastewater constituents. In other cases, the model equations and the assumptions made by their authors were questionable. Hence, two new activated sludge models with SMP and EPS as additional components have been formulated, described, and simulated. The first model is based on the Activated Sludge Model No. 1 (ASM1) whereas the second model is based on the Activated Sludge Model No. 3 (ASM3). Both models are calibrated on two sets of data obtained from a laboratory-scale system and a full-scale system and prove to be in very good agreement with the measurements. The second part of this thesis explains the development of two membrane fouling models. These models are set to describe the loss of membrane permeability during filtration of various solutions and suspensions. The main emphasis is placed on filtration of activated sludge mixtures, however the models are designed to be as general as feasibly possible. As fouling is found to be caused by a large number of often very complex processes which occur at different spatial as well as temporal scales, the two fouling models developed here have to consider a number of significant simplifications and assumptions. These simplifications are required to balance the model's accuracy, generality and completeness with its usability in terms of execution times, identifiability of parameters and ease of implementation in general purpose simulators. These requirements are necessary to ascertain that long term simulations as well as optimisation and sensitivity studies performed in this thesis either individually on fouling models or on the complete model of a MBR can be carried out within realistic time-scales. The first fouling model is based on an idea that fouling can be subdivided into just two processes: short-term reversible fouling and long-term irreversible fouling. These two processes are described with two first order ordinary differential equations (ODEs). Whilst the first model characterises the membrane filtration process from an observer's input-output point of view without any rigorous deterministic description of the underlying mechanisms of membrane fouling, the second model provides a more theoretical and in-depth description of membrane fouling by incorporating and combining three classical macroscopic mechanistic fouling equations within a single simulation framework. Both models are calibrated on a number of experimental data and show good levels of accuracy for their designated applications and within the intended ranges of operating conditions. In the third part, the first developed biological model (CES-ASM1) is combined with the behavioural fouling model and the links between these two models are formulated to allow complete simulation of a hollow fibre (HF) immersed membrane bioreactor (iMBR). It is assumed that biological processes affect the membrane through production of mixed liquor suspended solids (MLSS), SMP and EPS which cause pore blockage, cake formation, pore diameter constriction, and affect the specific cake resistance (SCR). The membrane, on the other hand, has a direct effect on the bulk liquid SMP concentration due to its SMP rejection properties. SMP are assumed to be solely responsible for irreversible fouling, MLSS is directly linked to the amount of cake depositing on the membrane surface, whereas EPS content in activated sludge affects the cake's SCR. Other links provided in the integrated MBR model include the effects of air scouring on the rate of particle back-transport from the membrane surface and the effects of MLSS concentration on oxygen mass transfer. Although backwashing is not described in great detail, its effects are represented in the model by resetting the initial condition in the cake deposition equation after each backwash period. The MBR model was implemented in Simulink® using the plant layout adopted in the MBR benchmark model of Maere et al. [160]. The model was then simulated with the inputs and operational parameters defined in [36, 160]. The results were compared against the MBR benchmark model of Maere et al. [160] which, contrary to this work, does not take into account the production of biopolymers, the membrane fouling, nor any interactions between the biological and the membrane parts of an MBR system.

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Pereira, Sofia Filipe. « Modelling of a wastewater treatment plant using GPS-X ». Master's thesis, Faculdade de Ciências e Tecnologia, 2014. http://hdl.handle.net/10362/13621.

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Dissertation to obtain the degree of Master in Chemical and Biochemical Engineering
The work present in this thesis was conducted in Portucel Soporcel mill, in the industrial complex of Setúbal, and had as main objective the modelling of the treatment process of the effluents from this industry, using for this purpose the software GPS-X. This program has a clear-cut graphical interface and uses a specialized translator that converts the graphical process into material balance equations, based on dynamic models. These models allow, besides the kinetic descripton of the treatment process carried out at the WWTP, to simulate new scenarios towards the study of critical parameters for the process as well as optimization and control of the WWTP. The effluent that arrives to Portucel’s WWTP, from the pulp and paper mills of the complex, is particularly rich on fibers (solids), lignin, chlorinated and sulphur compounds, resin acids, phenols and starch. It has a brown colour due to the presence of lignin and has a high oxygen chemical demand (about 1,095 g O2/m3). The WWTP uses the activated sludge process with extended aeration. This method allows an efficient removal of organics at the same time as it minimizes the sludge production. For the modelling of the process it was necessary to collect historical data related to the WWTP’s performance over the last 3 years. This data was used as input values for the influent characterisation and as output values to achieve the treated effluent characterisation. Since the first simulation did not lead to the desired output results, it was necessary to proceed to the model calibration, by means of a more detailed study concerning the nutrient and organic fractions of the influent. Once the model was calibrated, a study of the urea flowrate was conducted. The urea is added to the influent, before the beginning of the biological oxidation, as a way to satisfy the nitrogen requirements along the treatment process. However, this flowrate was never submitted to a study that evaluated, in a higher detail, the effective requirements of this nutrient. Thus, some simulations were done using the software, by decreasing successively the value of the urea flowrate and the results obtained were analyzed. Furthermore, these simulations were validated in the WWTP itself, at Portucel, through the decrease of the urea flowrate to half the normal value. Both the simulations and Portucel’s results showed that, actually, the addition of urea is not necessary because it does not affect the treatment process in a significant way, namely in terms of the removal of chemical oxygen demand. The simulations have also showed that the concentration of nitrogen in the final effluent diminishes significantly with the reduction of the urea flowrate, which could be advantageous in an environmental point of view.

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Pavasant, Prasert. « Modelling of the extractive membrane bioreactor process ». Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266478.

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Lumbers, Jeremy. « Rotating biological contactors : mechanisms, modelling and design ». Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47161.

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Milathianakis, Emmanouil. « Modelling and future performance assessment of Duvbacken wastewater treatment plant ». Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210704.

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Duvbacken wastewater treatment plant in Gävle, Sweden, currently designed for 100,000 person equivalent (P.E.) is looking for a new permit for 120,000 P.E. due to the expected increase of the population in the community. Moreover, the recipient of the plant’s effluent water was characterized as eutrophic in 2009. The plant emissions are regulated regarding seven days biological oxygen demand (BOD7) and total phosphorus (Ptot) emissions. Yet, there is no available computer model to simulate the plant operations and investigate the emissions of the requested permit. However, it was uncertain if the available data would be sufficient for the development of a new model. A model of the plant was eventually developed in BioWin® software under a number of assumptions and simplifications. A sensitivity analysis was conducted and used conversely than in other studies. The sensitivity analysis was conducted for the uncalibrated model in order to indicate its sensitive parameters. The parameters of substrate half saturation constant for ordinary heterotrophic organisms (KS) and phosphorus/acetate release ratio for polyphosphate accumulating organisms (YP/acetic) were finally used for model calibration. Following, the model validation confirmed the correctness of the calibrated model and the ability to develop a basic model under data deficiency. The new model was used to investigate a loading scenario corresponding to 120,000 P.E. where plant emissions that meet the current permits were predicted. Some suggestions proposed were the installation of disc filters in order to further reduce the effluent phosphorus and BOD precipitation in cases of high influent concentrations. In case of the application of a nitrogen (N) permit, the installation of membrane bioreactors and a full-scale chemical P removal was proposed as an alternative that will require a smaller footprint expansion of the plant.

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Chen, Jining. « Modelling and control of the activated sludge process : towards a systematic framework ». Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.295963.

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Tikilili, Phumza Vuyokazi. « Performance and modelling of non-granular anammox culture for wastewater treatment ». Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/61340.

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The anammox process is the latest biological process for removing nitrogenous compounds from wastewater. Anammox has been widely studied for the removal of nitrogen from various wastewaters. Despite intensive research for the past two decades to fully understand these processes, there is still some doubt related to the implementation of full-scale systems. Various characteristics of the anammox process, such as the reaction stoichiometry and the kinetic characteristics are still the predominant subjects. Slow bacterial growth and inhibition are the major causes of unsuccessful trials in the lab scale systems, and further prevent up scaling to pilot scale and the implementation of full-scale. Kinetic parameters of interest, such as the substrate affinity constant and maximum specific growth rate, which have been reported in literature, vary widely. Most studies on the anammox processes have been focused on granule-based cell cultures. Parameter values reported in literature are often hindered by mass transfer resistance associated with larger granules of microbial culture. In this study, the enrichment of free cells suspension culture is described. The free-cells suspension of highly active anammox bacteria was further used for detailed kinetic analysis of the anammox process. Firstly, the existence and diversity of anammox bacteria from various local habitats was investigated. Batch systems were used to enrich anammox biomass from sludge collected from three municipal wastewater treatment works in Pretoria. Anammox activity was tested and detected in two of the three wastewater treatment works after 90 days of primary enrichment. The activity was confirmed by the consumption of both NH4+ and NO2- in the system. The presence of anammox bacteria was also confirmed by PCR amplification of the 16S rRNA of the anammox using the anammox specific primers. All clones retrieved were closely related to the Brocadia species and were abundant in all habitats tested. The maximum growth rate of anammox for batch experiments was also estimated using a relatively new model. The denitrifying capability of pre-enriched suspended anammox culture was evaluated using a Sequencing Batch Reactor (SBR) and operated for a period of 120 days. The anammox process achieved high substrate removal with an average total nitrogen removal rate of 2.6 gNL-1 d-1, and reaching a maximum TN removal efficiency of 93%. For ammonium and nitrite, maximum removal efficiencies of 93% and 98%, respectively, were obtained. Stable performance was observed after 10 days of operation. Phylogenetic analysis confirmed the presence of anammox bacteria that are closely related to the Candidatus Brocadia species with 16S rRNA sequence similarity of 98%. In addition, a substrate removal model was also employed to simulate and predict the performance of the anammox reactor. According to the model predictions, the maximum substrate removal rate of the reactor should be 34 g.N.L-1.d-1. According to the model validation, the modified Stover-Kincannon model was suitable for the nitrogen removal description in the anammox SBR with a high correlation coefficient of R2=0.9739. Further experiments were conducted that focused on improving the anammox process using genetic engineering. In order to improve the anammox nitrogen removal efficiency, E. coli was genetically engineered to express the hydrazine oxidoreductase enzyme, a key enzyme in the anammox process. Batch reactors containing simulated wastewater were inoculated with transgenic E. coli. After six days of incubation, a drastic removal of nitrite and nitrate was observed with maximum removal efficiencies of 93% and 98%, respectively. The start-up was immediate with the transgenic E. coli, as opposed to native anammox, which can take several months. The results obtained from this study have shown genetic engineering technology to be an innovative technology that can speed up the anammox process and improve efficiency and stability. The anammox culture enriched during this study had a biomass specific maximum growth rate of 0.31 d-1 which was slightly higher than most reported granule base cell cultures in literature. Additionally, the intrinsic half saturation constant for ammonium and nitrite were detected to be 0.054 and 0.024mg-N L-1, respectively.
Thesis (PhD)--University of Pretoria, 2016.
Chemical Engineering
PhD
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Korsak, Larisa. « Anaerobic treatment of wastewater in a UASB reactor ». Licentiate thesis, Stockholm : Kemi, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9633.

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Khalid, Muhammad Imran. « Development of an intelligent dynamic modelling system for the diagnosis of wastewater treatment processes ». Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1153.

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

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Chistiakova, Tatiana. « Ammonium based aeration control in wastewater treatment plants : Modelling and controller design ». Licentiate thesis, Uppsala universitet, Avdelningen för systemteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-349423.

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Wastewater treatment involves many processes and methods which make a treatment plant a large-scaled and complex system. A fundamental challenge is how to maintain a high process efficiency while keeping the operational costs low. The variety in plant configurations, the nonlinear behaviour, the large time delays and saturations present in the system contribute to making automation and monitoring a demanding task. The biological part of a wastewater treatment process includes an aeration of the water and this process has been shown to often result in the highest energy consumption of the plant. Oxygen supply is a fundamental part of the activated sludge process used for aerobic microorganisms growing. The concentration of the dissolved oxygen should be high enough to maintain a sufficient level of biological oxidation. However, if the concentration is too high the process efficiency is significantly reduced leading to a too high energy consumption. Hence, there are two motivations behind the aeration control task: process efficiency and economy. One of the possible strategies to adjust the dissolved oxygen level in a nitrifying activated sludge process is to use ammonium feedback measurements. In this thesis, an activated sludge process is modelled and analysed in terms of dissolved oxygen to ammonium dynamics. First, the data obtained from a simplified Benchmark Simulation Model no.1 was used to identify the system. Both linear and nonlinear models were evaluated. A model with a Hammerstein structure where the nonlinearity was described by a Monod function was chosen for a more thorough study. Here, a feedback controller was designed to achieve L2-stability. The stability region was pre-computed to determine the maximum allowed time delay for the closed loop system. Finally, a feedforward controller was added to the system, and shown to significantly improve the disturbance rejection properties.

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Naghdy, G. « Identification, modelling and on-line computer control of a wastewater treatment process ». Thesis, University of Portsmouth, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370913.

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Rosendahl, Sara. « Modelling control strategies for chemical phosphorus removal at Tivoli wastewater treatment plant ». Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-453546.

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Wastewater compose an environmental risk as it contains high levels of nutrients, including phosphorus. Wastewater treatment plants (WWTPs) reduce phosphorus by using coagulants that precipitate soluble phosphate into metal phosphate, which is separated by settling. Coagulant flow is regulated by a control strategy, typically feedforward or feedback control. Feedforward is based on incoming wastewater disturbances whereas feedback control uses outgoing process values. Incoming phosphate is hard to measure and can be estimated using soft sensors. Modelling control strategies can help decide which strategy that is most suitable. Models describing phosphorus removal are Activated Sludge Model, ASM2d, and primary clarifier model. ASM2d models phosphorus precipitation and the primary clarifier model settling of particles. Tivoli WWTP faces challenges to reach effluent requirements of phosphorus. The wastewater flows through an equalisation tank, Regnbågen, before being pumped to Tivoli. Particulate matter settles in Regnbågen, which is removed by reducing the water level in Regnbågen. This rapidly increases incoming particulate load to Tivoli.Tivoli’s current control strategy is feedforward proportional to suspended solids. It is suspected, that this strategy overdose coagulant during the emptying of Regnbågen. The purpose of this thesis was to find the optimal control strategy for phosphorus precipitation at Tivoli WWTP, by using a model-based approach. Control strategies modelled are; feedforward, feedback and these two control strategies combined. Additional issues resolved are 1) calibration of a model that predicts the effect of chemical dosage on effluent phosphorus concentration from the primary clarifier, 2) calibrationof a soft sensor, 3) determination of which control strategy that is most suitable. ASM2d and a primary clarifier model were used to create a model describing chemical phosphorus removal. The calibration matches measured phosphate concentration, but underestimate peaks. The primary clarifier model was calibrated by minimising load differences for phosphate and total suspended solids, and was calibrated satisfyingly. A simplified soft sensor was constructed, described by a linear relationship between phosphate and pH. Three disturbances for feedforward control were analysed; measured phosphate, the soft sensors estimation of phosphate and Tivoli’s current controlstrategy. The optimal control strategy was found through a multi-criteria analysis. The optimal control strategy is the combined control strategy, when feedforward is proportional to incoming measured phosphate. The performance of all analysed feedforward disturbances were significantly improved when combined with feedback control. Furthermore, consequential errors are distinct when the soft sensor miss-predictincoming phosphate concentration. If the phosphate concentration cannot be correctly measured/estimated, feedback control alone has the best performance.

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FERREIRA, REBOUCAS Taise. « ENVIRONMENTAL FOOTPRINT REDUCTION FOR WASTEWATER TREATMENT BY MULTI-OBJECTIVE OPTIMIZATION AND MODELLING ». Doctoral thesis, Università degli Studi di Palermo, 2020. http://hdl.handle.net/10447/395510.

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The current challenge faced by researchers and managers is minimize the environmental footprint of wastewater treatment plants (WWTPs). To accomplish this goal, other than respect legal requirements, WWTPs must provide better responses regarding consumption of energy and resources, greenhouse gas (GHG) emissions, among others. The research hereby presented is based on the application of mathematical modelling with the aim to propose a framework for the minimization of WWTP’s environmental footprint towards optimization techniques. A literature review was held to gain knowledge regarding the main decision support systems (DSS) that are applied to WWTPs since they allow selecting the most appropriate solutions regarding the plant’s performance. The DSSs were also investigated to understand their main uses while applied to WWTPs. It has been found that mathematical models (MMs) are very often applied to the wastewater treatment, especially regarding conventional activated sludge (CAS) and membrane bioreactors (MBRs). It was also noted that none of the works applied MMs with a multi-objective purpose towards minimizing their environmental footprint. On this behalf, two stationary process-based mathematical models were developed in order to carry out a comprehensive comparison between CAS (Model I) and MBR (Model II) in terms of GHG emissions and energy consumption. Model I was applied to a full-scale real plant located in the city of Irvine, in California, while Model II was applied to a semi-hypothetical case study obtained by replacing the secondary settler of the CAS with a membrane bioreactor. Results showed that the MBR demanded more energy than the CAS due to the aeration required by the activated sludge process (ASP). MBRs were also found to be responsible for higher indirect emissions. Following the previous results, a focus was given to the ASP of MBRs. Since MBR’s ASP is mainly composed by the integration of biological and physical treatments, a literature review was held to gain knowledge regarding the integrated MBR modelling. Results led to the proposition of a framework towards the optimization of MBR’s environmental footprint. Additionally, some opportunities were revealed regarding MBR modelling, leading to the update of an integrated MBR dynamic model, which was applied to an University of Cape Town (UCT) MBR pilot-plant. The new model was able to assess the plant’s performance in terms of ten performance indicators (PIs) related to effluent quality (EQI), operating costs (OC), energy demand (eD), and GHG emissions. Simulations were held to understand the influence of five operational parameters over the ten PIs (benchmark scenario). The method Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was adopted for the optimization of modelling results (optimal scenario). A comparison between the benchmark and optimal scenarios showed an amelioration in the plant’s performance in terms of GHG direct and indirect emissions, energy consumption and operational costs at the expenses of a negligible decay of effluent quality. An optimization technique based on instrumentation, automation and control (ICA) principles was applied to the same UCT-MBR. The approach considered real-time variations of oxygen and ammonia concentrations within the aerated compartments to propose a disturbance-based optimization also in terms of EQI, OC, eD and GHG. The comparison between benchmark and ICA scenarios showed a reduction of 31%, 38%, and 31% in terms of eD, indirect emissions, and OC, respectively, for the ICA scenario. Finally, a user-friendly software-based model was applied to an integrated fixed-film activated sludge (IFAS) MBR pilot plant with the aim to optimize its performance in terms of EQI, eD, OC and GHG by the control of operational parameters. Results retrieved from this work showed great potentiality, but further scenarios should be encouraged to understand the minimum and maximum threshold for C/N ratios so plant can maintain positive results, which may encourage further research. Additionally the software-based approach allowed personalizing a comprehensive dynamic mathematical model in a small amount of time, without recurring to extensive modelling tools based on a programming language. The framework proposed by this research is a novelty in the literature since no studies were previously published with the aim to provide an assessment of advanced treatments in terms of EQI, eD, OC and GHG. Such a comprehensive assessment demonstrated the importance of a model-based DSS to obtain the best trade-off during performance optimization. Finally, the successful application to five different case studies demonstrates that the framework is trustworthy and that can help decision-makers in finding the best trade-off between accuracy and complexity while looking for predictive answers.
The current challenge faced by researchers and managers is minimize the environmental footprint of wastewater treatment plants (WWTPs). To accomplish this goal, other than respect legal requirements, WWTPs must provide better responses regarding consumption of energy and resources, greenhouse gas (GHG) emissions, among others. The research hereby presented is based on the application of mathematical modelling with the aim to propose a framework for the minimization of WWTP’s environmental footprint towards optimization techniques. A literature review was held to gain knowledge regarding the main decision support systems (DSS) that are applied to WWTPs since they allow selecting the most appropriate solutions regarding the plant’s performance. The DSSs were also investigated to understand their main uses while applied to WWTPs. It has been found that mathematical models (MMs) are very often applied to the wastewater treatment, especially regarding conventional activated sludge (CAS) and membrane bioreactors (MBRs). It was also noted that none of the works applied MMs with a multi-objective purpose towards minimizing their environmental footprint. On this behalf, two stationary process-based mathematical models were developed in order to carry out a comprehensive comparison between CAS (Model I) and MBR (Model II) in terms of GHG emissions and energy consumption. Model I was applied to a full-scale real plant located in the city of Irvine, in California, while Model II was applied to a semi-hypothetical case study obtained by replacing the secondary settler of the CAS with a membrane bioreactor. Results showed that the MBR demanded more energy than the CAS due to the aeration required by the activated sludge process (ASP). MBRs were also found to be responsible for higher indirect emissions. Following the previous results, a focus was given to the ASP of MBRs. Since MBR’s ASP is mainly composed by the integration of biological and physical treatments, a literature review was held to gain knowledge regarding the integrated MBR modelling. Results led to the proposition of a framework towards the optimization of MBR’s environmental footprint. Additionally, some opportunities were revealed regarding MBR modelling, leading to the update of an integrated MBR dynamic model, which was applied to an University of Cape Town (UCT) MBR pilot-plant. The new model was able to assess the plant’s performance in terms of ten performance indicators (PIs) related to effluent quality (EQI), operating costs (OC), energy demand (eD), and GHG emissions. Simulations were held to understand the influence of five operational parameters over the ten PIs (benchmark scenario). The method Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was adopted for the optimization of modelling results (optimal scenario). A comparison between the benchmark and optimal scenarios showed an amelioration in the plant’s performance in terms of GHG direct and indirect emissions, energy consumption and operational costs at the expenses of a negligible decay of effluent quality. An optimization technique based on instrumentation, automation and control (ICA) principles was applied to the same UCT-MBR. The approach considered real-time variations of oxygen and ammonia concentrations within the aerated compartments to propose a disturbance-based optimization also in terms of EQI, OC, eD and GHG. The comparison between benchmark and ICA scenarios showed a reduction of 31%, 38%, and 31% in terms of eD, indirect emissions, and OC, respectively, for the ICA scenario. Finally, a user-friendly software-based model was applied to an integrated fixed-film activated sludge (IFAS) MBR pilot plant with the aim to optimize its performance in terms of EQI, eD, OC and GHG by the control of operational parameters. Results retrieved from this work showed great potentiality, but further scenarios should be encouraged to understand the minimum and maximum threshold for C/N ratios so plant can maintain positive results, which may encourage further research. Additionally the software-based approach allowed personalizing a comprehensive dynamic mathematical model in a small amount of time, without recurring to extensive modelling tools based on a programming language. The framework proposed by this research is a novelty in the literature since no studies were previously published with the aim to provide an assessment of advanced treatments in terms of EQI, eD, OC and GHG. Such a comprehensive assessment demonstrated the importance of a model-based DSS to obtain the best trade-off during performance optimization. Finally, the successful application to five different case studies demonstrates that the framework is trustworthy and that can help decision-makers in finding the best trade-off between accuracy and complexity while looking for predictive answers.

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Pierong, Rasmus. « Modelling of algae based wastewater treatment : Implementation of the River Water Quality Model no. 1 ». Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226484.

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The conventional wastewater treatment of today was developed aiming to mitigate problems occurring in wastewater recipients such as oxygen depletion and eutrophication. The focus of wastewater management has however broadened and major concern is now focused on the sustainability of the wastewater treatment process itself. Algae based wastewater treatment is an alternative to conventional treatment. It has the potential to yield an acceptable effluent quality at a lower ecological cost. This Degree Project was conducted as part of MOBIT, a project at Mälardalen University. The MOBIT project was aimed at the development of an algae based wastewater treatment process in an activated sludge environment. The aim of this Degree Project was to propose a model describing the dynamics of such a system. The model was constructed in Simulink, based on the River Water Quality Model no. 1. The River Water Quality Model no. 1 was chosen as the basis for modelling because it included the state variables and processes necessary to describe the dynamics of bacteria, algae and pH. The River Water Quality Model no. 1 was, as the name suggests, developed to describe a river system. It was hence considered important to evaluate if the model was applicable to an activated sludge environment. A major obstacle was the fact that no algae based activated sludge system had been studied prior the start of the MOBIT project, the project was pioneering. The lack of system understanding and of measurement data aggravated the evaluation. However, the proposed model was compared to the Activated Sludge Model No. 1 which was known to describe an activated sludge system accurately. The model structure of the River Water Quality Model no. 1 was considered a good starting point for future modelling of the algae based activated sludge process. However, the model set-up proposed in this report does not describe the system sufficiently well. Better system understanding and measurement data is needed in order to develop and calibrate the model.
Dagens konventionella avloppsvattenrening har utvecklats för att minimera utsläpp av näringsämnen och kolföreningar då sådana utsläpp medför övergödning och syrebrist i mottagande vatten. På senare tid har reningsprocessen i sig hamnat i fokus då den är såväl energi- som resurskrävande. Algbaserad avloppsvattenrening är ett alternativ som har potential att ge tillfredsställande rening med ett betydligt mindre ekologiskt fotavtryck. Det här examensarbetet var en del av MOBIT, ett projekt vid Mälardalens högskola. MOBIT syftade till att utvärdera algbaserad avloppsvattenrening i form av en aktivslamprocess. Syftet med examensarbetet var att ta fram en modell för det planerade systemet. Modellen byggdes i Simulink och den baserades på en befintlig modell, River Water Quality Model no. 1. Den befintliga modellen valdes för att den inkluderade alla önskvärda tillståndsvariabler och processer, bland annat de som krävs för att beskriva alg-, bakterie- och pH-dynamik. Som namnet antyder utvecklades River Water Quality Model no. 1 för att beskriva ett flodsystem. Det var därför angeläget att utvärdera huruvida modellen var tillämpbar i en aktivslammiljö. Utvärderingen försvårades av att det vid tiden för examensarbetets utförande ännu inte fanns någon existerande algbaserad aktivslamprocess. Kunskapen om systemet var därför begränsad och det fanns ingen mätdata att kalibrera eller evaluera mot. I brist på mätdata jämfördes den framtagna modellen med en annan modell som var utvecklad för att beskriva just avloppsvattenrening, Activated Sludge Model No. 1. Arbetet resulterade i slutsatsen att River Water Quality Model no. 1 utgör en bra grund för modellering av den algbaserade aktivslamprocessen. Men, den modellkonfiguration som tas fram i denna rapport beskriver inte systemet särskilt bra. Bättre systemförståelse samt tillförlitlig mätdata krävs för att omarbeta och kalibrera den föreslagna modellen.
MOBIT

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Fornander, Erik. « Ozone Treatment Targeting Pharmaceutical Residues : Validation and Process Control in a Wastewater Treatment Plant ». Thesis, Linköpings universitet, Teknisk biologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-154012.

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Major studies conducted in Europe and North America has concluded that the current processes in wastewater treatment plants insufficiently degrade micropollutants e.g. pharmaceutical residues. Several sorption and oxidation methods has therefore been investigated with the purpose of removing or degrading micropollutants in wastewater. The main purpose of this project was, firstly, to validate the results from a pilot study conducted by Tekniska verken i Linköping AB (2014) which investigated the use of ozone to degrade pharmaceutical residues. Secondly, to investigate and design a suitable process control strategy for the ozonation process. Four different tests were conducted during the project, a dose-response test, step-response tests, a trace test, and a performance test. A poorer average reduction of pharmaceutical residues was observed in this project compared to the pilot study. An average reduction of approximately 80% was observed at the highest tested dose, 0.67 mg O3/mg DOC, N corr. Whilst an average reduction of 90% was observed at approximately 0.46 mg O3/mg DOC, N corr, in the pilot study. However, the quality of the wastewater was worse during this project compared to the pilot study. ΔUVA254 and offgas concentration of ozone were found to be suitable control parameters for process control. A control strategy based on a combination of these parameters was designed, where ΔUVA254 was used as the main control parameter and the off-gas concentration of ozone was used as a limiting controller to ensure a sufficient mass transfer in the system. In conclusion, a suitable flow proportional base ozone dose valid for current water conditions has been identified, 10 mg/L. Differences in wastewater quality which heavily influence the ozonation process have been identified. Lastly, a control strategy for process control of the ozonation have been identified, designed and is ready for implementation.

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Ahranjani, Nayrah Khandani. « Modelling of a Suspended Floc in Wastewater Treatment Systems using Object-Oriented Programming ». Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.519487.

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Loureiro, Cláudia Filipa Reis Galinha. « Monitoring and modelling of membrane bioreactors for wastewater treatment incorporating 2D fluorescence spectroscopy ». Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/13108.

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Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica, Especialidade em Engenharia Bioquímica
Os biorreactores de membranas (MBRs, ‘membrane bioreactors’) para o tratamento de águas residuais combinam o processo de lamas activadas com um passo de filtração para obtenção de um efluente limpo, livre de sólidos. Os MBRs representam uma tecnologia em expansão no tratamento de águas residuais sobretudo devido ao reduzido espaço que requerem e à elevada qualidade do efluente obtido. No entanto, a colmatação das membranas pode reduzir o desempenho do MBR. Por este motivo, no presente trabalho, pretendeu-se estudar a monitorização dos MBRs, com o objectivo de minimizar o número de parâmetros de monitorização necessários para descrever o desempenho do processo e obter uma monitorização em tempo real com recurso mínimo a técnicas laboratoriais demoradas. Para este fim, estudou-se a aplicabilidade da fluorescência bidimensional em meios biológicos complexos, tais como as lamas activadas utilizadas para o tratamento de águas residuais. A fluorescência bidimensional mostrou ser uma técnica abrangente, capaz de recolher informação relevante sobre o estado do sistema em tempo real. Devido à complexidade da informação contida nos espectros de fluorescência, usaram-se técnicas de estatística multivariada, tais como análise de componentes principais e projecção de estruturas latentes (PLS, ‘projection to latent structures’), para extrair a informação dos espectros e correlacioná-la com parâmetros de operação e de desempenho do MBR. O uso de modelos estatísticos permitiu a previsão de parâmetros chave para o desempenho do MBR usando somente dados de processo impostos ou facilmente adquiríveis em tempo real. Adicionalmente, a modelação estatística foi combinada com um modelo mecanístico, numa estrutura híbrida, de forma a melhorar a previsão mecanística. Este estudo demonstrou ser possível usar modelos PLS para incorporar dados de fluorescência obtidos em tempo real, de modo a melhorar a previsão mecanística sem requerer análises laboratoriais adicionais.

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Giaccherini, Francesca [Verfasser], et Thomas [Akademischer Betreuer] Dockhorn. « Modelling tannery wastewater treatment to evaluate alternative bioprocesses configurations / Francesca Giaccherini ; Betreuer : Thomas Dockhorn ». Braunschweig : Technische Universität Braunschweig, 2017. http://d-nb.info/1175817414/34.

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Giaccherini, Francesca Verfasser], et Thomas [Akademischer Betreuer] [Dockhorn. « Modelling tannery wastewater treatment to evaluate alternative bioprocesses configurations / Francesca Giaccherini ; Betreuer : Thomas Dockhorn ». Braunschweig : Technische Universität Braunschweig, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:084-2017062210012.

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Gullman, Isak. « Improved prediction of biogas production at Uddebo wastewater treatment plant : Substrate modelling in SIMCA ». Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85463.

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Anaerobic digestion is a complex process, dependent on multiple factors, which can be made more stable and efficient with the help of process models. A more stable process could reduce biogas torching, which increases the amount of renewable energy available for heat- and electricity production and vehicle fuel. Fluctuations in the produced biogas at Uddebo WWTP in Luleå, Sweden, has been observed, where imported industrial waste was suspected to be the cause. The purpose of this master thesis was to increase the predictability of the biogas production at Uddebo WWTP by creating a process model based on historical data. The historical data consisted of quantitative data of the substrates loaded into the anaerobic digestor and biogas collected from the digestor. The results showed that the calculated error between modelled and measured biogas production was <20%, which was considered good. However, due to the demarcation of this report, many variables were ignored in the creation of the model. Further research is therefore a requirement for the model to function properly: The error should be reduced to <10%, This could be done by increasing the period and resolution toinclude and statistically secure fast and seasonal variations. make qualitative modelling easier, i.e., prediction of the biomethane amount in the biogas. The industrial liquid waste storage should be included in the calculation. A more detailed analysis of all substrates is needed to make the comparison between the literature based and measured production more realistic. Expanding the demarcation of the model to also include the environment in the digestor. This could also increase the total amount of biogas produced.

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Stenlund, Olle. « Design and Modelling of a Container for Optimal Flow Rate and Wastewater Purification ». Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-183669.

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Industries are becoming more aware of how they use water in their production process. In many cases, they release wastewater back into the water supply untreated, which can cause adverse side effects to the ecosystem. A sustainable environment requires efficient water purification. One approach to purify wastewater uses rotating bed reactors. An impeller filled with catalyst pellets that absorb the pollutants spins in the contaminated fluid. The inertial forces from the spinning impeller propel the contaminated water through the packed bed and purify it. In this study, we used one of these rotating bed reactors. However, the motors that drive these impellers can be bulky and may not be compatible with some tanks or environments. To solve this problem, we designed, constructed, and tested a container around the impeller that provides maximal outflow, using only the impellers pumping capability. We also developed a CFD simulation of the container to analyze the internal flows and forces. Because the flow generated by the rotating impeller displaces the fluid in a radial direction, the design works as a custom-made centrifugal pump. We constructed the container using plastic and wood with an outlet nozzle made of metal. The container's pump capability was around 2.5 liters per second when the impeller spun at 300 RPM. The developed CFD simulations gave a higher flow rate at 3.1 liters/second but overall helped shed light on the internal forces happening inside the container during high RPM testing. The design could generate a sufficient outflow of fluids, converting kinetic fluid energy to fluid pressure energy at the outlet, causing a pump effect. Overall, the design proved sturdy and could handle the forces occurring inside the container. The implementation of this design could allow industries to more efficiently and ergonomically utilize the purifying capabilities of the RBR in otherwise complex scenarios. By purifying wastewater before releasing it back into the water supply, we can take immediate action in achieving a sustainable environment.

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Rodriguez, Raul. « Upflow anaerobic sludge blanket reactor : modelling ». Licentiate thesis, KTH, Kemisk apparatteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-29521.

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Anaerobic treatment is widely used around the world as a biological stage in both domestic and industrial wastewater-treatment plants. The two principal advantages of anaerobic over aerobic treatment are the production of biogas, which can be used as fuel, and the lower rate of biomass production, which results in lower maintenance costs for the plant. The upflow anaerobic sludge blanket (UASB) reactor is an attractive alternative for regions in hot climates since it works better under mesophilic conditions and it does not need any supporting structure for the development of microorganisms, which grow in the form of granules. In this thesis, a model describing the UASB reactor behaviour with respect to substrate degradation, microorganism growth and granule formation was developed. The model is transient and is based on mass balances for the substrate and microorganisms in the reactor. For the substrate, the processes included in the model are dispersion, advection and degradation of the organic matter in the substrate. The reaction rate for the microorganisms includes the growth and decay of the microorganisms. The decay takes into account the microorganism dying and the fraction of biomass that may be dragged into the effluent. The microorganism development is described by a Monod type equation including the death constant; the use of the Contois equation for describing the microorganism growth was also addressed. An equation considering the substrate degradation in the granule was required, since in the UASB reactor the microorganisms form granules. For this, a stationary mass balance within the granule was carried out and an expression for the reaction kinetics was then developed. The model for the granule takes into account the mass transport through the stagnant film around the granule, the intraparticle diffusion, and the specific degradation rate. The model was solved using commercial software (COMSOL Multiphysics). The model was validated using results reported in the literature from experiments carried out at pilot scale. A simplified model was also developed considering the case in which the microorganisms are dispersed in the reactor and granules are not formed. The UASB reactor is then described as formed by many well-stirred reactors in series. The model was tested using experimental results from the literature and the sensitivity of the processes to model parameters was also addressed. The models describe satisfactorily the degradation of substrate along the height in the reactor; the major part of the substrate is degraded at the bottom of the reactor due to the high density of biomass present in that region. This type of model is a useful tool to optimize the operation of the reactor and to predict its performance.
QC 20110203

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Dalmau, Solé Jordi. « Knowledge-based modelling and simulation of operational problems of microbiological origin in wastewater treatment plants ». Doctoral thesis, Universitat de Girona, 2009. http://hdl.handle.net/10803/33690.

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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.

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Rustum, Rabee. « Modelling activated sludge wastewater treatment plants using artificial intelligence techniques (fuzzy logic and neural networks) ». Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2207.

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Activated sludge process (ASP) is the most commonly used biological wastewater treatment system. Mathematical modelling of this process is important for improving its treatment efficiency and thus the quality of the effluent released into the receiving water body. This is because the models can help the operator to predict the performance of the plant in order to take cost-effective and timely remedial actions that would ensure consistent treatment efficiency and meeting discharge consents. However, due to the highly complex and non-linear characteristics of this biological system, traditional mathematical modelling of this treatment process has remained a challenge. This thesis presents the applications of Artificial Intelligence (AI) techniques for modelling the ASP. These include the Kohonen Self Organising Map (KSOM), backpropagation artificial neural networks (BPANN), and adaptive network based fuzzy inference system (ANFIS). A comparison between these techniques has been made and the possibility of the hybrids between them was also investigated and tested. The study demonstrated that AI techniques offer viable, flexible and effective modelling methodology alternative for the activated sludge system. The KSOM was found to be an attractive tool for data preparation because it can easily accommodate missing data and outliers and because of its power in extracting salient features from raw data. As a consequence of the latter, the KSOM offers an excellent tool for the visualisation of high dimensional data. In addition, the KSOM was used to develop a software sensor to predict biological oxygen demand. This soft-sensor represents a significant advance in real-time BOD operational control by offering a very fast estimation of this important wastewater parameter when compared to the traditional 5-days bio-essay BOD test procedure. Furthermore, hybrids of KSOM-ANN and KSOM-ANFIS were shown to result much more improved model performance than using the respective modelling paradigms on their own.

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Arnau, Notari María Rosario. « Hydrodynamic and biochemical Computational Fluid Dynamic modelling of full-scale anaerobic digesters for wastewater treatment ». Doctoral thesis, Universitat Jaume I, 2022. http://dx.doi.org/10.6035/14107.2022.234094.

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Anaerobic digestion is one of the most widely used biological treatments for the stabilisation of sewage sludge, but the effectiveness of the process depends on good mixing. The Computational Fluid Dynamics (CFD) technique allows analysing the mixing and hydrodynamics, so it has been widely used to study anaerobic digestion. In this thesis, hydrodynamics in full-scale digesters have been studied by means of CFD models, evaluating their mixing systems by means of different scenarios according to mixing and design parameters and dead volumes. In a second part, a new CFD solver was developed to couple a biological model with hydrodynamics and applied to a laboratory and a full-scale digester. The last part was devoted to evaluate the hydrodynamic behaviour of biogas bubbles in anaerobic sludge, so that local mixing by biogas bubbles in anaerobic digesters was evaluated. Future work needs to focus on experimental measurements and new two-phase CFD models.
Programa de Doctorat en Tecnologies Industrials i Materials

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Guo, Li Sha. « Greenhouse gas emissions from and storm impacts on wastewater treatment plants : process modelling and control ». Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25360.

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Cette thèse étudie l'interaction entre les stations d’épuration (STEP) et le changement climatique: soit en premier lieu la production ainsi que les émissions de gaz à effet de serre (GES), en particulier le protoxyde d’azote (N2O), généré à la STEP et en second lieu l’effet des pluies plus intenses dues aux changements climatiques sur la STEP. Des campagnes de mesure sur le terrain et la modélisation à échelle réelle ont été utilisées conjointement dans cette recherche. Une campagne de mesure d'une durée d’un mois a été réalisée dans une STEP traitant les eaux usées de 750,000 équivalents habitants, soit la STEP d’Eindhoven aux Pays-Bas. Des capteurs en ligne ont été installés dans la zone d'aération du bioréacteur. Une usine virtuelle de grande échelle, soit la STEP décrit par le Benchmark Simulation Model No.2 (BSM2), ainsi qu’une usine réelle de grande échelle, soit la STEP d’Eindhoven aux Pays-Bas, étaient incluses dans cette étude. Dans les deux cas, les modèles ont été modifiés afin de prendre en compte les GES, en particulier la production de N2O. Deux modèles de boues activées (ASM) ont été développés, soit l’ASMG1 et l’ASMG2d. En plus de la conversion de N2O par les bactéries hétérotrophes, les deux modèles sont en mesure de simuler la production de N2O par la dénitrification catalysée par les bactéries oxydant l'ammoniac (AOB). Les modèles décrivent aussi l'effet de l’oxygène dissous (OD) sur la cinétique de production de N2O par les AOB grâce à une modification de la cinétique d’Haldane. Les résultats montrent que les AOB produisent beaucoup de N2O tandis que les hétérotrophes en consomment considérablement. Les émissions de N2O augmentent lorsque les concentrations de NH4+ sont élevées et que les concentrations d’OD sont modérées (jusqu’à 2.5 mg O2/l dans cette étude). Ces conditions peuvent avoir été créées par le contrôle en cascade de NH4+-OD qui vise à réduire la consommation d'énergie en diminuant les concentrations d'OD lorsque la concentration de NH4+ est suffisamment faible. En outre, ce contrôleur en cascade est une stratégie de rétroaction à gain faible. C'est-à-dire, un retard significatif se produit entre la détection d'une augmentation de NH4+ et l'accroissement de l'aération. Toutes ces propriétés produisent des conditions favorables à la production de N2O par les bactéries AOB. Différents scénarios alternatifs ainsi que des stratégies de contrôle ont été comparés selon la qualité de l'effluent, le coût d’opération et les émissions de GES. Dans le cadre de BSM2, un bon équilibre entre la qualité de l'effluent, le coût d’opération et les émissions de GES a été obtenu avec à la mise en œuvre d'un contrôleur rétroactif pur de l’OD sur la première zone d'aération et d’un contrôleur en cascade de NH4+-DO sur les deux zones d'aération suivantes et en utilisant soit une stratégie d'alimentation étagée ou le contrôle du recyclage des boues afin de gérer les pics de débits. Mots-clés: Traitement des eaux usées par boues activées, contrôle de procédé, campagne de mesures en terrain, modélisation mathématique à échelle grandeur réelle, gaz à effet de serre, protoxyde d’azote, temps de pluie.
This PhD thesis studied the interaction between wastewater treatment plants (WWTPs) and climate change, i.e. the production and emission of greenhouse gases (GHGs), especially nitrous oxide (N2O), from WWTPs and the effect of the climate change induced more intense rain events on WWTPs. Both field measurements and full-scale modelling were pursued in this research. A one-month measurement campaign was performed by installing on-line sensors at the aeration zone of the bioreactor of a 750,000 person equivalents WWTP, i.e. the Eindhoven WWTP in the Netherlands. The models of a full-scale virtual plant, i.e. the Benchmark Simulation Model No.2 (BSM2), and a full-scale real plant, i.e. the Eindhoven WWTP in the Netherlands, were extended with respect to GHG emissions, especially the pathways involving N2O. Two types of extended Activated Sludge Models (ASM) were developed, i.e. ASMG1 for COD/N removal and ASMG2d for COD/N/P removal. Besides heterotrophic N2O production, both proposed models include N2O production by nitrite denitrification by ammonia-oxidizing bacteria (AOB) and describe the DO effect on AOB N2O production by a modified Haldane kinetics term. Results showed that AOB are the major producer of N2O while the heterotrophs consume N2O considerably. The high N2O emissions occurred under high NH4+ and intermediate DO concentrations (up to 2.5 mg O2/l in this work). Such conditions can be created by NH4+-DO cascade control which aims at reducing energy consumption by lowering the DO concentrations when the NH4+ concentration is sufficiently low. Moreover, this cascade controller is a low-gain feedback control strategy, i.e. a significant delay will occur between the detection of a NH4+ increase and the increase in aeration. All these properties lead to conditions favourable to N2O production by AOB. Different alternative scenarios and control strategies were compared in terms of effluent quality, operational cost and GHG emissions. In the framework of BSM2, a good balance among effluent quality, operational cost and GHG emissions was realized by implementing a pure DO feedback controller in the first aeration zone and a NH4+-DO cascade controller in the following two aeration zones and using either step feed or sludge recycling control to deal with hydraulic shocks. Keywords: Activated sludge, wastewater treatment, process control, field measurements, full-scale mathematical modelling, greenhouse gases, nitrous oxide, wet weather conditions.

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Fiorentino, Carmine <1978&gt. « Modelling to Manage Activated Sludge Wastewater Treatment Plant and Facultative Lagoons Finishing for Irrigation Reuse ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8054/1/Fiorentino_Carmine_tesi.pdf.

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In the last years, the role of wastewater treatment plants has become even more relevant not only as final destination of the collected sewage but also as a center of the sustainable approaches for the water cycle. Moreover, the considerable improvements in wastewater treatment control technologies enable now the implementation of advanced sustainable management perspectives. A particular incentive to increase the efficiency of WWTPs performances comes from the possibility to reuse treated wastewater. In this context, the overall aim of this PhD thesis was to investigate the implementation of models in the most relevant sections of pilot and full-scale plants, and to study the possibility on reusing treated wastewater coming from the effluent flow rate of existing plants for irrigation purpose. We have implemented the WEST 2012 modeling software that allows different control policies using data acquired on a pilot plant located in Trebbo di Reno (Italy). These simulations have evidenced the real possibility to manage small-scale plants with automatic controller while respecting the legal limits for discharge. We have also studied the finishing effect of the natural treatment phase using data recorded during several monitoring campaigns on the Santerno full-scale plant located in Imola (Italy). The removal efficiency resulting from the monitoring campaigns reaches 40% for Ammonium and 20% for Total Nitrogen. The disinfection capacity, E. coli removal efficiency up to 40%, does not permit irrigation reuse so appropriate management policies are necessary. In addition, a pilot plant has been designed and implemented in the Santerno area and the first monitoring data show a real possibility to test management policies first in the pilot-plant and then on full scale plant. Finally, we observed that organic chemicals in wastewater treatment plant have a low biodegradability and can be drastically accumulated during irrigation, which represents a critical issue in the future.

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Echaroj, S. « Process evaluation and mathematical modelling of the anaerobic rotating biological contactors (RBC) process for wastewater treatment ». Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375138.

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Al-Obaidi, Mudhar A. A. R. « Modelling, Simulation, and Optimisation of Reverse Osmosis Process with Application in Wastewater Treatment and Food Processing ». Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/17345.

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Reverse Osmosis (RO) is a membrane-based separation process applied in several industrial and food processing applications. In this research, performance of RO process is investigated in respect of two applications (a) wastewater treatment (b) concentration fruit juices using model-based techniques. For this purpose, a number of models (both 1 and 2-dimensional steady state and dynamic) for spiral wound RO process are developed based on Solution-Diffusion model and Irreversible Thermodynamic model. The models are validated against actual experimental data reported in the literature before being used in further simulation and optimisation studies for both wastewater treatment and fruit juice concentration. Wastewater effluents of many industrial applications contain a variety of micro-pollutants and highly-toxic compounds, which are released into a variety of water resources. Such pollutants not only disrupt the biological ecosystem, but they also pose a real threat to the water supply for human consumption and to the aquatic ecosystems. The earlier chapters of the thesis evaluate the performance of RO process in terms of removal efficiency of toxic compounds such as chlorophenol, N-nitrosamine, etc. from wastewater. The effect of several operating parameters such as feed pressure, concentration, flow rate and temperature, on the performance of RO process are evaluated. Also, suitability of a number of different RO configurations for efficient removal of toxic compounds are evaluated. For example, (a) two-stage/two-pass RO design synthesis of RO network for the removal of chlorophenol (b) multistage multi-pass RO process with and without energy recovery option for the removal of N-nitrosamine are investigated. The dynamic response of the RO process for step changes in the operating parameters is investigated for the removal of phenolic compounds. Finally, in the context of wastewater treatment, a case study with multi compounds contaminants is suggested where a multi-objective optimisation problem has achieved the optimum rejection of all the compounds and recovery rate. In respect of food processing, RO has been considered as a prominent process in fruit juice concentration due to its ability to effectively retain the flavour, sensory, aroma and nutritional characteristics and concentrate the juice. This research elucidates one example of apple juice concentration process and focuses on highlighting successful modelling and optimisation methodology. This in turn provides an efficient method of RO process for concentrating apple juice by improving the reliability and efficiency of the underlying separation and concentration process.
Ministry of High Education and Scientific Research of Iraq

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Al, Ketife Ahmed Majeed Daife. « Modelling and Optimization of Combined Wastewater Treatment and CO2 Bio-fixation in a Batch Algal Photobioreactor ». Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/59696.

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The research focuses on investigation and optimization (using Box Behnken design) of the key parameters of CO2 gas concentration, light intensity, temperature, feedwater nutrient concentration, and wastewater origin (municipal primary and secondary, and petroleum industry) on photobioreactor algal growth parameters. A mathematical model is provided for predicting algal growth. Finally, the influence of light wavelength on algal growth is investigated. The outcomes can be used to inform design and operation of large-scale algal cultivation systems.

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Pouzol, Tanguy. « Monitoring and modelling of pharmaceuticals in wastewater : Daily and hourly loads in both hospital and urban wastewater ». Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI009/document.

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Les flux journaliers et horaires de 15 molécules pharmaceutiques à l'entrée d'une station d'épuration ont été mesurés sur 3 ans et modélisés à la fois pour un bassin urbain de 16 000 habitants et un hôpital de 450 lits. Certaines molécules ne sont jamais ou rarement quantifiées. Les flux journaliers vont de 0,6 à 564 g/jour en fonction de la molécule et de la campagne de mesure 24h. Aucune dynamique saisonnière ou hebdomadaire n’a été identifiées. La dynamique des flux horaires des médicaments se distingue des autres polluants et du débit des eaux usées. Les flux horaires mesurés sont sévèrement impactés par le comportement aléatoire des patients lorsque la masse journalière consommée est faible. Ainsi, la dynamique moyenne est difficile à identifier. L'hypothèse principale pour modéliser les flux de médicaments dans les eaux usées est qu'ils résultent des étapes suivantes: ventes ou distributions de médicaments, consommation humaine, métabolisme et excrétion. Les ventes de médicaments pour le bassin urbain et les distributions de l'hôpital ont été collectées à différentes échelles spatiales et temporelles (respectivement 1, 6 et 223 pharmacies et journalières, hebdomadaires et mensuelles). Les plus grandes échelles sont plus fiables pour estimer les niveaux de consommations mais la variabilité des plus petites est plus proche de la variabilité observée dans les mesures. Les quantités de médicaments vendus ou distribués vont de 0,4 à 1 600 patients théoriques par jour en moyenne. En associant les flux journaliers mesurés aux ventes ou aux distributions, aucune corrélation linéaire n'a été trouvée. Un modèle stochastique au pas de temps de la minute est proposé et appliqué aux deux sites. Il produit des résultats fiables et précis pour les flux quotidiens et horaires. Cependant, les résultats sont difficiles à interpréter lorsque seuls quelques patients consomment un médicament. De plus, le modèle ne reproduit pas la spécificité inhérente de l'hôpital. En outre, le modèle est également capable de prédire avec précision le débit des eaux usées domestiques d'un bassin versant urbain, tant pour les volumes quotidiens que pour leurs dynamiques
Daily and hourly loads of 15 pharmaceutical molecules at the inlet of a wastewater treatment plant have been measured over 3 years and modelled for both an urban catchment of 16 000 inhabitants and a hospital of 450 beds. Some molecules are never or rarely quantified. Daily loads range from 0.6 to 564 g/day depending of the molecule and the 24 h measurement campaign. Seasonal or weekly patterns are not identified. Pharmaceuticals hourly loads dynamics are distinctive from one another and from wastewater flow. The measured hourly loads are severely impacted by the random behaviour of the patients when the daily mass consumed is low. Thus, the average dynamics is difficult to identify. The main hypothesis to model pharmaceuticals loads in wastewater is that they result from the following steps: pharmaceuticals sales or distributions, human consumption, metabolism and excretion. Pharmaceuticals sales for the urban catchment and distribution for the hospital have been collected at different space and timescales (respectively 1, 6 and 223 pharmacies and daily, weekly and monthly). Larger scales are more reliable for magnitude but the variability of the smaller ones is closer to the variability observed in the measurements. The quantities of pharmaceuticals sold or distributed range from 0.4 to 1 600 theoretical patients per day. Associating measured daily loads with sales or distributions, no linear correlation is found. A minute time step stochastic model is proposed and applied to both sites. It produces reliable and accurate results for both daily and hourly loads. However, results are difficult to interpret when only a few patients are consuming a pharmaceutical. Also, the model does not reproduce the inherent specificity of the hospital. In addition, the model is also able to predict the domestic wastewater flow of an urban catchment with great accuracy for both daily volumes and dynamics

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Rodríguez-Gómez, Raúl. « Closing the Loop by Combining UASB Reactor and Reactive Bed Filetr Technology for wastewater Treatment : Modelling and Practical Approaches ». Doctoral thesis, KTH, Mark- och vattenteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182990.

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A laboratory-scale upflow anaerobic sludge blanket (UASB) reactor followed by a packed bed reactor (PBR) filled with Sorbulite® in the lower part and Polonite® in the upper part was used to treat household wastewater in a 50-week experiment. A model was developed to describe the performance of the UASB reactor, including mass transfer through the film around anaerobic granules, intra-particle diffusion and bioconversion of the substrate. In a second model, a numerical expression describing the kinetics occurring in the granules was developed. It includes the resistances through which the substrate passes before biotransformation. These expressions were then linked to governing equations for the UASB reactor in order to describe degradation of the substrate, biomass growth (active and inactive), and variation in granule size over time. A third model was developed to describe the profile of the phosphorus (P) concentration throughout the PBR. In a first attempt, the analytical and numerical model was applied to data taken from previous studies in which UASB reactors were used to treat sugarcane mill wastewater and slaughterhouse wastewater. The results showed good agreement between observed and simulated results. Sensitivity analysis showed that diffusion coefficient and yield were important parameters in the UASB reactor model.The laboratory bench-scale experiment revealed that the combined UASB-PBR system efficiently treated the residential wastewater. Phosphorus, BOD7 and pathogenic bacteria all showed average removal of 99%, while total nitrogen showed a moderate reduction in the system (40%). Application of the numerical solution model to the experimental UASB reactor used resulted in good agreement between simulated and experimental values. Regarding the PBR, the model developed successfully predicted P removal. For both models, the capability and sensitivity analyses identified important parameters. A treatment system aiming to close the loop is suggested based on sequential UASB and PBR with biogas collection, nutrient recycling via sludge and filter media and elimination of pathogenic organisms.

QC 20160226

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Bisinella, de faria Ana barbara. « Development of an integrated approach for wastewater treatment plant optimization based on dynamic modelling and environmental assessment ». Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0039/document.

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Les stations d’épuration se tournent actuellement vers des installations de récupération d'énergie et des nutriments. Dans le même temps, elles sont soumises à une réglementation de plus en plus stricte en ce qui concerne l'environnement et la santé humaine. Face au défi ambitieux de réduire les coûts d'exploitation et les impacts environnementaux tout en garantissant la robustesse du procédé, il est nécessaire de développer des outils capables de fournir une évaluation intégrée du procédé. L’objectif de ce travail est de développer une plateforme réaliste et prédictive contenant trois aspects: la modélisation rigoureuse et dynamique de l’ensemble de la station d’épuration; l'analyse de cycle de vie aux frontières étendues pour l'évaluation des scénarios et enfin un outil d'optimisation multi-objectif efficace. La plateforme développée pour l'évaluation environnementale couplée à la modélisation dynamique a d'abord été appliquée à plusieurs cas d’étude. Ainsi des résultats de performance et d’impacts environnementaux ont été obtenus pour la séparation de l’urine à la source, la décantation primaire avancée et le traitement de l'urine par nitritation/ oxydation anaérobie de l’ammonium, et d’autres filières. Compte tenu des importants avantages de la séparation de l’urine établis par les résultats précédents, un générateur d’influents phénoménologique, flexible et dynamique a été adapté afin de fournir des données dynamiques réalistes concernant les flux d'urine et des eaux usées dans les différents scénarios de rétention d'urine. Enfin, comme la combinaison complexe de processus biologiques, chimiques et physiques conduit à un problème lourd en calcul, une étude de faisabilité (temps de calcul et fiabilité) a été réalisée sur l'optimisation multi-objectif. L'obtention d'un ensemble de solutions qui évite toute discrimination préalable entre les coûts, l'environnement et les performances ont permis la discussion des enjeux impliqués. Finalement, la plateforme complète a été appliquée à plusieurs cas d’étude et clarifie les aspects opérationnels des options plus durables en matière de gestion et de traitement des eaux usées
Wastewater treatment plants are moving towards energy and nutrients recovery facilities. Simultaneously, they are submitted to stricter regulation with respect to environment and human health. Facing the great challenge of reducing operational costs along with the reduction of environmental impacts and the guaranty of plants robustness, tools might be developed in order to provide an integrated assessment. The goal of this work is to develop a reliable and predictive framework containing rigorous dynamic wide-plant modelling, extended boundaries life cycle assessment for scenarios evaluation and an efficient multi-objective optimization tool. The developed framework for environmental evaluation coupled to dynamic modelling was initially applied to several case studies including urine source separation, enhanced primary clarification and urine treatment by nitritation/ anaerobic ammonium oxidation, offering both performance results and environmental hotspots. Given the important benefits of the urine source separation provided by the previous results, a flexible and dynamic phenomenological influent generator was adapted in order to provide realistic dynamic data concerning urine and wastewater streams in different urine retention scenarios. Finally, as the complex combination of biological, chemical and physical processes leads to a computational expensive problem, a feasibility study (computational time and reliability) on the multi-objective optimization was conducted. Obtaining a set of solutions that avoids any prior discrimination among costs, environment and performance allowed thus the discussion of the involved trade-offs. Finally, the complete framework was applied to several case studies lightening on operational aspects of more sustainable options on wastewater management and treatment

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MEI, ROBERTO. « MULTIVARIABLE MODELLING AND CONTROL OF CONTINUOUS PROCESSES : Wastewater treatment plants and complex fluids production as case studies ». Doctoral thesis, Università degli Studi di Cagliari, 2019. http://hdl.handle.net/11584/259120.

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In this thesis, the multivariable modelling and control of continuous processes is discussed. Two main lines of research were followed: the multivariable system identification for processes subjected to disturbances and the multivariable modelling and control of a continuous production of complex fluids. For the first topic, wastewater treatment plants were used as case study. The goal of the work was to develop a method to implement multivariable variations of the manipulated inputs chosen for the identification phase, in order to obtain as much information as possible on the system in the shortest time. Signals for manipulated inputs were randomly generated according to the Generalized Binary Noise approach and inputs combinations were selected on the basis of the D-Optimal Design criterion. The Benchmark Simulation Model No. 1 was used as process simulator. Non-linear autoregressive neural networks were implemented to evaluate transfer functions of linear models. The procedure allowed to obtain good results as regards the estimation of gain constants of such models. For the second topic, the production of non-Newtonian water-free detergents was considered as case study, with the goal to develop control strategies for such process. Rheological characterization of the product was addressed by means of rheometers and a viscometer. The Carreau model was chosen for the description of the rheological behaviour. The process was first modelled relating the parameters of the Carreau model with the mass flow rate of one ingredient. A single-input single-output feedback Proportional-Integral controller was designed with the purpose to control a point on the viscosity curve of the product. The main outcome was that a viscosity curve was controllable with such control configuration, but the selection of the right controlled variable needs particular care. A second modelling attempt was made exploiting a multi-input multi-output control configuration. A process simulator based on a non-linear neural network was built. A double feedback controller was implemented with the objective to control two separate points of the viscosity curve using two manipulated variables. A Model Predictive Control was designed with the purpose to control more than two points on the viscosity curve using the same manipulated variables. The second controller returned faster responses in terms of dynamics with respect to the double feedback controller. Finally, the possibility to control the detergent production process by using an on-line ultrasound rheological sensor was explored. A data-driven approach was applied by means of Partial Least Squares technique and neural networks, in order to obtain a model capable to relate ultrasound variables with off-line rheological measurements of viscosities of the product. Fittings of experimental data by the neural network were better than those obtained with the Partial Least Squares model. A "smart operator" action was implemented as a control system, by means of a second neural network model. Thus, the control system was based on two data-driven models based on neural networks. Simulated tests of this control algorithm returned satisfactory results, proving the possibility of a real-time control of the viscosity curve of a complex fluid during its continuous production.

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Renman, Agnieszka. « On-site wastewater treatment : Polonite and other filter materials for removal of metals, nitrogen and phosphorus ». Doctoral thesis, KTH, Mark- och vattenteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4811.

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Bed filters using reactive materials are an emerging technology for on-site wastewater treatment. Chemical reactions transfer contaminants from the aqueous to the solid phase. Phosphorus is removed from domestic wastewater by sorption to filter materials, which can then be recycled to agriculture as fertilisers and soil amendments. This thesis presents long-term column and field-scale studies of nine filter materials, particularly the novel product Polonite®. Phosphorus, nitro-gen and metals were removed by the mineral-based materials to varying degrees. Polonite and Nordkalk Filtra P demonstrated the largest phosphorus removal capacity, maintaining a PO4-P removal efficiency of >95%. Analysis of filter bed layers in columns with downward wastewater flow, showed that phosphorus, carbon and nitrogen content was vertically distributed, with de-creasing values from surface to base layer. Polonite and Filtra P accumulated 1.9-19 g P kg-1. Nitrogen in wastewater was scarcely removed by the alkaline filter materials, but transformation from NH4-N to NO3-N was >90%. Pot experiments with barley (Hordeum vulgare L.) revealed that after wastewater treatment, slags and Polonite could increase plant production. Batch experi-ments and ATR-FTIR investigations indicated that amorphous tricalcium phosphate (ATCP) was formed in the materials, so some of the accumulated PO4-P was readily available to plants. Low heavy metal contents occurred in the materials, showing that they can be applied as soil amend-ments in agriculture without contamination risks. A full-scale treatment system using Polonite as filter material showed an average PO4-P removal efficiency of 89% for a 92-week period, indicat-ing the robustness of the filter bed technology.
QC 20100907

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Jonfelt, Clara. « An evaluation of an MBBR anammox model - sensitivity analysis and calibration ». Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-312511.

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This master thesis is about mathematical modelling of the anammox process with a moving bed biofilm reactor (MBBR) for a reject water application. Specifically, the aim of my research was to find out whether the model proposed by Erik Lindblom in (Lindblom et al. 2016) is a good model for this purpose and worth continuous research and optimization. The code for the model, implemented in Matlab/Simulink, was given; although not initially functioning in the given condition. Some modifications needed to be done to make it function properly. In order to confirm that the code was working and used in a correct way some results in (Lindblom et al. 2016) were reproduced. Before starting the evaluation of the model, some much-needed optimizations of the code were done, substantially reducing the run time. A sensitivity analysis was done, and the five most sensitive parameters were picked out to be used in the calibration. The calibration improved the total fit of the model to the available measurements, although one of the model outputs could not be calibrated satisfactorily. In short, I found that although there are still problems left to solve before the model can be stated to accurately model the anammox process with MBBR, it appears promising. Most importantly, more measurement data are needed in order to make a proper validation and to do a better calibration.
CONAN

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Guisasola, i. Canudas Albert. « Modelling biological organic matter and nutrient removal processes from wastewater using respirometric and titrimetric techniques ». Doctoral thesis, Universitat Autònoma de Barcelona, 2005. http://hdl.handle.net/10803/5306.

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Climent, Agustina Javier. « Development of a modelling tool to perform hydrodynamics coupled with biological processes in the secondary stage of wastewater treatment plants ». Doctoral thesis, Universitat Jaume I, 2019. http://hdl.handle.net/10803/668408.

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Simulation models based on tools associated with computational fluid dynamics (CFD) and applied to wastewater treatment have been developed. The hydrodynamic effect of the internal elements that govern the flow behavior in the biological reactors combined with the biochemical models that reproduce the purification process has been investigated. An experimental work of validation of CFD models has been carried out in real scale.
Se han desarrolado modelos de simulación basados en herramientas asociadas a la dinámica computacional de fluidos (CFD) y aplicados al tratamiento de aguas residuales. Se ha investigado el efecto hidrodinámico de los elementos internos que gobiernan el comportamiento del flujo en los reactores biológicos combinado con los modelos bioquímicos que reproducen el proceso de depuración. Se ha realizado un trabajo experimental de validación de modelos CFD a escala real.

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45

Tan, Benjamin L. L. « Chemical and Biological Analyses of Selected Endocrine Disruptors in Wastewater Treatment Plants in South East Queensland, Australia ». Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365603.

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Studies in North America, Europe, Japan and Australia have reported the presence of endocrine disrupting compounds (EDCs) in wastewater treatment plants (WWTPs) effluent could affect physiological and reproductive function in exposed fish consistent with exposure to hormonally active chemicals. The occurrence of EDCs in rivers and receiving environments situated near WWTPs raises concern over the removal efficacy of these compounds by conventional treatment processes. The main aim of this study was to utilize chemical analyses to assess concentrations of selected endocrine disruptors as well as a biological assay to measure the potential estrogenic effects of EDCs present in water discharged from wastewater treatment plants in South East Queensland, Australia. Currently, there are few reported studies on the estrogenic effects of EDCs released from WWTPs into receiving environments in Australia. Two field sampling methods were used. Grab sampling with subsequent extraction using a solid-phase extraction (SPE) technique and passive sampling utilizing EmporeTM (styrene-divinylbenzene copolymer) disk were used in this study. A gas chromatography-mass spectrometric (GC-MS) method was successfully developed to simultaneously analyze 15 environmentally ubiquitous EDCs including phthalates, alkylphenols, tamoxifen, androgens and estrogens. Application of these methods for the determination of target EDCs in wastewater samples in this study showed 80 – 99% removal of most EDCs from influent to effluent, despite the wastewater treatment plants having different treatment processes. It was observed that the passive samplers accumulated less EDCs than predicted when compared to the grab samples. This is probably caused by, but may not be limited to, biofouling, low flow rate, biodegradation and temperature which can progressively reduce the uptake of compounds into the sampler. A future challenge would be to improve the reliability of passive samplers by reducing or controlling the environmental conditions that may impact on the passive sampler performance. Stir bar sorptive extraction (SBSE) in combination with thermal desorption coupled to GC-MS was successfully applied to analyze a range of EDCs in wastewater, biosolids and sludge. The technique was shown to be very versatile, shortening extraction time, reducing sample volume needed as well as being sensitive for the analysis of a wide range of EDCs. The results showed that there were high amounts of phthalates, alkylphenols and female hormones present in the raw influent wastewater and biosolids of the WWTP samples. For the complimentary bioassay, a proliferation assay using human breast cancer cell line MCF-7 (E-Screen assay) was used to determine estrogen equivalents (EEqs) in grab and passive samples from five municipal WWTPs. EEq concentrations derived by E-Screen assays for the grab samples were between 108 – 356 ng/L for the influents and <1 – 14.8 ng/L for the effluents with the exception of one effluent sample which was at 67.8 ng/L EEq. In most wastewater samples, the natural estrogens contributed to 60% or more of the EEq value. Based on the chemical and in vitro biological analyses results and coupled with reported no observed effect concentration (NOEC) in vivo studies (mainly based on fish vitellogenin studies), the risk of EDCs found in effluents of the monitored WWTPs having a significant impact on the receiving environment is reasonably low. Furthermore, a fugacity-based analysis was employed to model the fate of selected industrial chemicals with endocrine disrupting properties in a conventional activated sludge WWTP. Using mass balance principles, a fugacity model was developed for correlating and predicting the steady state-phase concentrations, the process stream fluxes, and the fate of four phthalates and four alkylphenols in a WWTP. The relative amounts of chemicals that are likely to be volatilized, sorbed to sludge, biotransformed, and discharged in the effluent water was assessed. Results obtained by applying the model for the eight compounds compared satisfactorily with data from the WWTP. All eight EDCs modelled in this study had high removal efficacy from the WWTP. Apart from benzyl butyl phthalate and bisphenol A, the majority is removed via biotransformation followed by a lesser proportion removed through primary sludge. Fugacity analysis provides useful insight into compound fate in a WWTP and with further calibration and validation the model should be useful for correlative and predictive purposes. In conclusion, the complementary chemical and biological analyses used in this study provided a comprehensive assessment which showed that the EDCs discharged from the monitored WWTPs would be expected to have a low impact on the receiving environments.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Faculty of Environment and Planning
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46

Mahlathi, Christopher Dumisani. « In-Stream water quality modelling and optimisation by mixed-integer programming : simulation and application in actual system ». Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/40840.

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Water scarcity has become a global problem due to diminishing water resource and pollution of the remaining resources. The problems arising fromwater scarcity are exacerbated rapid urbanisation and industrialisation. Water quality management systems are introduced. Numerous water management methods exist some of which, if applied e ectively, can remedy these problems. In South Africa, water management systems are urgently needed to start addressing issues around the longterm sustainability of our limited water resource. Water quality modelling is one of the tools employed to assist in validating decisions made during the planning phase of a water quality management system. It also provides a means of exploring viable options to be considered when these decisions are to be made. A range of management options exist and implementing all of them may prove costly, therefore optimisation techniques are utilised to narrow down options to the most e ective and least costly among the available choices. Commonly, water quality models are used to predict concentrations in the river from which constraint equations are generated. The constraint equations are used in optimisation models to generate feasible solutions by either maximising or minimising the objective function. In this case the objective function is wastewater treatment cost. Constraints equations are based on the set in-stream water quality standard at selected theoretical measuring stations (checkpoints) in the stream and a feasible solution is one that suggests a treatment method that will ensure water quality standards are met at the lowest regional treatment cost. This study focused on the Upper Olifants river catchment near Witbank in Mpumalanga province. This catchment is subjected to extensive wastewater e uents from various mining operations and wastewater treatment plants. The aim here was to develop a water quality model for predicting dissolved oxygen (DO) concentration in the river, and to use a modelling approach to generate constraint equations for the system. A Streeter-Phelps stream simulation model was employed to predict DO concentration in the river. A mixed-integer programming technique was then used to evaluate the impact of nine wastewater treatment facilities discharging e uent into the river. Treatment levels were varied to test model reliability. The coupled stream simulation and optimisation model produced feasible solutions under 2 minutes, with each solution suggesting a range of treatment levels which ensured that the critical DO concentration was above 5 mg/L and the most stringent DO concentration the system could manage without violations anywhere else in the stream was obtained to be 7mg/L.
Dissertation (MEng)--University of Pretoria, 2013.
gm2014
Chemical Engineering
unrestricted

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47

Derdar, Mawaheb M. Zarok. « Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase. Experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitatated semi-batch gas/liquid reactor ». Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.

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Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17¿-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17¿-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.
Ministry of Higher Education in Libya and the Libyan Cultural Centre and Educational Bureau in London.

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48

Derdar, Mawaheb M. Zarok. « Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase : experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitated semi-batch gas/liquid reactor ». Thesis, University of Bradford, 2010. http://hdl.handle.net/10454/4872.

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Résumé :

Due to the ever increasing concerns about pollutants and contaminants found in water, new treatment technologies have been developed. Ozonation is one of such technologies. It has been widely applied in the treatment of pollutants in water and wastewater treatment processes. Ozone has many applications such as oxidation of organic components, mineral matter, inactivation of viruses, cysts, bacteria, removal of trace pollutants like pesticides and solvents, and removal of tastes and odours. Ozone is the strongest conventional oxidant that can result in complete mineralisation of the organic pollutants to carbon dioxide and water. Because ozone is unstable, it is generally produced onsite in gas mixtures and is immediately introduced to water using gas/liquid type reactors (e.g. bubble columns). The ozone reactions are hence of the type gas liquid reactions, which are complex to model since they involve both chemical reactions, which occur in the liquid phase, and mass transfer from the gas to the liquid phase. This study focuses on two aspects: mass transfer and chemical reactions in multicomponent systems. The mass transfer parameters were determined by experiments under different conditions and the chemical reactions were studied using single component and multicomponent systems. Two models obtained from the literature were adapted to the systems used in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas-liquid mass transfer rates. An experimental study was carried out to investigate the effects of t-butanol concentrations on the physical properties of aqueous solutions, including surface tension and viscosity. It was found that t-butanol reduced both properties by 4% for surface tension and by a surprising 30% for viscosity. These reductions in the solution physical properties were correlated to enhancement in the mass transfer coefficient, kL. The mass transfer coefficient increased by about 60% for oxygen and by almost 50% for ozone. The hydrodynamic behaviour of the system used in this work was characterised by a homogeneous bubbling regime. It was also found that the gas holdup was significantly enhanced by the addition of t-butanol. Moreover, the addition of t-butanol was found to significantly reduce the size of gas bubbles, leading to enhancement in the volumetric mass transfer coefficient, kLa. The multicomponent ozonation was studied with two systems, slow reactions when alcohols were used and fast reactions when endocrine disrupting compounds were used. ii These experiments were simulated by mathematical models. The alcohols were selected depending on their volatilization at different initial concentrations and different gas flow rates. The degradation of n-propanol as a single compound was studied at the lowest flow rate of 200 mL/min. It was found that the degradation of n-propanol reached almost 60% within 4 hours. The degradation of the mixture was enhanced with an increase in the number of components in the mixture. It was found that the degradation of the mixture as three compounds reached almost 80% within four hours while the mixture as two compounds reached almost 70%. The effect of pH was studied and it was found that an increase in pH showed slight increase in the reaction. Fast reactions were also investigated by reacting endocrine disrupting chemicals with ozone. The ozone reactions with the endocrine disrupters were studied at different gas flow rates, initial concentrations, ozone concentrations and pH. The degradation of 17β-estradiol (E2) as a single compound was the fastest, reaching about 90% removal in almost 5 minutes. However estrone (E1) degradation was the lowest reaching about 70% removal at the same time. The degradation of mixtures of the endocrine disruptors was found to proceed to lower percentages than individual components under the same conditions. During the multicomponent ozonation of the endocrine disruptors, it was found that 17β-estradiol (E2) converted to estrone (E1) at the beginning of the reaction. A MATLAB code was developed to predict the ozone water reactions for single component and multicomponent systems. Two models were used to simulate the experimental results for single component and multicomponent systems. In the case of single component system, good simulation of both reactions (slow and fast) by model 1 was obtained. However, model 2 gave good agreement with experimental results only in the case of fast reactions. In addition, model 1 was applied for multicomponent reactions (both cases of slow and fast reaction). In the multicomponent reactions by model 1, good agreement with the experimental results was also obtained for both cases of slow and fast reactions.

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Aymerich, Blazquez Ignasi. « Integrated assessment of wastewater treatment plants and their receiving river systems in a global change context ». Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/670284.

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For a long time, there has been a need and an ambition to better understand the behavior of integrated systems by considering the whole urban water cycle, including wastewater transportation, wastewater treatment and the receiving water. On the other hand, fragmented environmental policies on wastewater sanitation, global change, and emerging contaminants are increasingly threatening freshwater ecosystems and human health. Within this context, this thesis embeds a series of research studies aiming to improve our comprehension of the functioning of urban wastewater systems (UWWS), considering both natural and artificial elements, and with a special emphasis on the occurrence of global change and on the fate of emerging contaminants. In the thesis, an integrated model for a UWWS in NE Iberian Peninsula has been developed and calibrated using data from an intensive and integrated survey, not only combining early developed mathematical models for the different sub-processes, but also verifying the model parameters with full-scale and dynamical measurements. More specifically, the work developed in this thesis was divided into three parts. First, we investigated how an UWWS perform together in the removal of conventional contaminants and evaluated the impact of future global change scenarios. Second, we investigated the occurrence and fate of pharmaceuticals and their transformation products in the UWWS. Finally, and as a continuation of the second work, we assessed the influence of the sampling strategy when estimating the loads and attenuation of emerging contaminants in UWWS under different scenarios differing from sampling strategies, consumption, and degradability of the compound under analysis. Overall, this thesis highlights the need for integrated approaches to better understand the performance of WWTPs and their receiving rivers, against the increase of micro-contaminants occurrence and the effects of global change
La necessitat i ambició per entendre millor el comportament dels sistemes de sanejament d’aigües residuals de forma integrada és una de les prioritats en la gestió de l’aigua, des de el transport, tractamet i descarrega als seus medis receptors. Per altra banda, les actual polítiques segmentades en la gestió dels sistemes de sanejament d'aigües residuals urbanes, el canvi global i l'ocurrència de contaminants emergents en els mitjans receptors, amenacen cada vegada més els ecosistemes d'aigua dolça i salut humana.En aquest sentit, aquesta tesi integra una sèrie d'estudis d'investigació que apunten a millorar la nostra comprensió en el funcionament dels sistemes d'aigües residuals urbanes (UWWS), considerant el conjunt d'elements naturals i artificials, i amb un èmfasi especial en els canvis globals i ocurrència dels contaminants emergents. Concretamemt. en aquesta tesi s'ha desenvolupat i calibrat un model integrat per a un UWWS al NE de la Península Ibèrica, utilitzant dades recollides durant intensa campanya integrada de monitorització, no només combinant avançats models per els diferents sub-processos, sinó també verificant els paràmetres de modelització amd dades dinàmiques i a escala. Més específicament, el treball desenvolupat en aquesta tesi s’estructura en tres parts. Primer, investiguem com funcionen els UWWS en l'eliminació de contaminants convencionals i avaluem l'impacte dels futurs escenaris de canvi global. Segon, avaluem l'ocurrència i la destinació dels productes farmacèutics i els seus productes de transformació en el UWWS. En tercer lloc, i com a continuació d'aquest segon treball, s’estudia la influència de diferents escenaris de mostreig, consum i degradabilitat dels compostos en l’estimació de càrregues i atenuació dels micro-contaminants en UWWS.En general, aquesta tesi destaca la necessitat d'enfocaments integrats per comprendre millor el rendiment de les EDAR i els seus rius receptors, per prendre mesures contra l'augment de les concentracions de micro-contaminants i els efectes del canvi global

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Chamoun, Ninus, Viktor Kjellvertz, William Mahajan et Yuanchao Song. « Fate of Heavy Metals in Waste to Energy (WtE) Processes ». Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208925.

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This study was made to increase the understanding of how heavy metals in the aqueous phase are removed at low initial concentrations in different pH and Eh values. The reaction that has been studied is mainly hydroxide precipitation and adsorption in a condensate treatment. In the study, data from one of Vattenfalls waste incinerators was analysed and the results from the data were then compared to previous studies. To increase the understanding, modelling of the heavy metals behaviour in the given concentrations was then made with Medusa and PHREEQC. The heavy metals that were analysed were Sb, As, Pb, Zn, Cr, and Cd. The low initial concentration that vary between 36.1-23600 μg/l complicates the removal process because it corresponds in a low driving force and the results are hard to compare to other studies since the initial concentrations vary between 10-100 mg/l. From the modelling and the measurement data it can be seen that Pb, Zn, Cr, and Cd was removed by hydroxide precipitation at pH 10. According to the speciation calculations, the dominant species at this pH are Pb(OH) 2 , Cd(OH)2, Zn(OH)2 and Cr(OH)3. For arsenic a clear conclusion could not be drawn from the modelling and the measurement data because of low precision. Due to the limited thermodynamic parameters of antimony in comparison with other heavy metals in the database of Medusa and PHREEQC, the modelling of antimony behaviour in condensate treatment has relatively larger uncertainty is low. The modelling results show that the main species in acidic solutions for antimony is Sb(OH)3 and in basic solutions Sb(OH)-6. Further investigation for antimony in needed for a clear conclusions to be drawn

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