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Elaboration et validation d'un modèle de simulation dynamique d'un chenal d'oxydation : couplage du modèle ASM1 et du modèle piston avec dispersion / Elaboration and validation of a dynamic model for the simulation of an oxidation ditchHaouech, Latifa 19 November 2012 (has links)
Le but de ce travail est le développement d’un modèle 1D pour la simulation du fonctionnement d’un chenal d’oxydation. Le couplage du modèle hydrodynamique et des cinétiques biologiques permettront une meilleure description du procédé. L’hydrodynamique dans le chenal est modélisée par un réacteur piston à dispersion axiale. Le transfert d’oxygène et les réactions biologiques sont aussi intégrés dans le modèle. Les réactions biologiques sont représentées par le modèle biologique ASM1 développé par Henze 1987 tenant compte de la dégradation du carbone et celle de l’azote. C’est un modèle tout à fait adapté pour la modélisation des processus biologique mis en jeu dans un chenal d’oxydation partiellement aéré. La validation du modèle développé a été effectuée par la comparaison avec les mesures effectuées sur une installation pilote de volume 1 m3 (Lesage 2002). Cette validation est faite en trois étapes : validation de l’hydrodynamique par la simulation de la distribution du temps de séjour, validation du transfert d’oxygène par la simulation de remontée d’oxygène en eau claire et validation du modèle biologique par la simulation de la réponse réspiromètrique. Le modèle développé est ensuite utilisé pour la simulation du fonctionnement d’une station à taille réelle celle de Mahrès (1300 m3). Des mesures des concentrations en oxygène dissous dans le chenal de Mahrès ont permis de distinguer une hétérogénéité spatiale et temporelle. La simulation à échelle réelle consiste à reproduire ces gradients de concentrations existant au sein du chenal après la détermination des paramètres du modèle par le biais de mesures expérimentales sur la station citée et par le calage du modèle cinétique de dégradation de l’azote. Ce travail dénote l’importance du modèle développé pour la simulation d’un procédé à boue activée avec une hydrodynamique particulière et une aération par alternance de zone où la zone anoxie est nécessaire pour la réaction de dénitrification / The aim of this study is to obtain a validated model for the description of an oxidation ditch system, which could be used as a decision tool. A spatio-temporal 1D model which integrates hydrodynamic, oxygen transfer and biologic kinetics was developed. This work provides a prediction of COD and nitrogen fractions and dissolved oxygen concentrations described by widely used ASM1 model (Henze et al., 1987). This model was validated on the experimental result obtained by a campaign measurement in lab scale activated sludge study having a volume of 1m3 (Lesage, 2002). This validation is made in three steps: hydrodynamic validation by the simulation of the residence time distribution, oxygen transfer validation by simulating oxygen rise in clear water and the biological model validation by the simulation of oxygen uptake rate. The model developed was used to simulate a full scale plant of 1300 m3. Such model can well predicts the plug flow behavior of dissolved oxygen exiting in large scale oxidation ditch and has the ability to simulate dynamic behavior of wastewater components. The full scale simulation is done after model parameters identification and calibration of nitrogen kinetics model parameters. This model can be used to perform real time prediction which can help to optimize nitrification and denitrification occurring in the ditch under dynamic load
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Aplicação do modelo ASM1 na simulação das condições operacionais de uma estação de tratamento de efluentes por lodo ativadoZOBY JUNIOR, Luiz Carlos 31 January 2011 (has links)
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Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O tratamento biológico por lodos ativados é um dos processos mais utilizados para o
tratamento de efluentes domésticos e industriais caracterizados por contaminação de
carga orgânica biodegradável e produtos nitrogenados. A modelagem computacional
destes sistemas de tratamento foi usada como instrumento de planejamento, projeto,
análise e operação da Estação de Tratamento de Efluentes (ETE) a partir da década de
1970. Os modelos destinados à simulação do tratamento das águas residuais são,
geralmente, desenvolvidos tendo em conta os processos unitários preponderantes,
podendo os aspectos hidráulicos serem aproximados de forma simplificada e modelados
explicitamente através de funções de transferência ou pelo método do volume do tanque
variável. Os modelos para lodo ativado (ASM) têm estimulado o desenvolvimento de
software e o conhecimento, cada vez mais detalhado, dos processos, possibilitando
consideráveis progressos na operação e gestão das ETE´s. Para o presente trabalho foi
realizada a calibração do modelo com os dados experimentais recolhidos na etapa de
caracterização da matéria orgânica em termo das variáveis de entrada das frações
orgânica e nitrogenada e na determinação dos parâmetros cinéticos e estequiométricos.
Em seguida, foi utilizada a plataforma de simulação do Benchmark Simulation Model 1
(BSM1) para a avaliação e previsão do funcionamento das ETE s Caçote e Janga
estudadas, visando estabelecer suas condições de operação. A avaliação foi conduzida
através de simulações do funcionamento da ETE e estas, por sua vez, dependem da
caracterização das matérias orgânicas e nitrogenada presentes no efluente. Na etapa de
caracterização global das amostras conclui-se que a ETE Caçote mesmo sendo de
pequeno porte recebe uma carga orgânica (carbono e nitrogênio) maior para ser tratada
e que nem uma das duas estações removem satisfatoriamente compostos nitrogenados
(amônio e nitrogênio orgânico). Quanto a composição dos efluentes estudados, para as
duas ETE´s, o teor de material orgânico biodegradável (Ss e Xs) foi muito elevado
situando-se na faixa de 70 à 90 % da Demanda Química de Oxigênio total (DQOT).
Enquanto que a matéria orgânica inerte (Si e Xi) apresentou concentração inferior a 18
% sendo que a coleta terceira coleta realizada no Janga compõe cerca de 30 % de
material refratário. Destas porcentagens os valores encontrados para a fração Xi não
foram significativos. Conforme dados da literatura, conclui-se que os valores
encontrados nesse trabalho de fracionamento da matéria orgânica coincidem com as
ordens de grandeza
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Modelling of algae based wastewater treatment : Implementation of the River Water Quality Model no. 1 / Modellering av algbaserad avloppsvattenrening : Implementering av River Water Quality Model no. 1Pierong, Rasmus January 2014 (has links)
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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Modélisation du procédé bioréacteur à membranes immergées : calage et validation du modèle ASM1 sur un site réel : étude des interactions boues activées, conditions opératoires et membraneDelrue, Florian 22 December 2008 (has links)
Les bioréacteurs à membranes (BAM) sont de plus en plus utilisés dans le domaine du traitement des eaux résiduaires urbaines notamment lorsque le terrain est limité ou qu’un traitement épuratoire poussé est requis. Néanmoins, la gestion de ces installations et plus particulièrement du colmatage des membranes reste difficile et constitue toujours une source de problèmes pour les exploitants. La modélisation est un outil efficace et déjà éprouvé sur les procédés conventionnels à boues activées pour l’aide à la conduite et à la compréhension de procédé avec les modèles de boues activées de type ASM. Le traitement biologique donc, et aussi les capacités de filtration des membranes (colmatage) sont deux aspects qui peuvent être modélisés sur les BAM. Au cours de ce travail, trois installations réelles ont été étudiées et l’une d’entre elles a été choisie pour le calage du modèle ASM1. La méthodologie a été adaptée aux spécificités des bioréacteurs à membranes et de l’installation modélisée en particulier (fractionnement des eaux usées, calage de l’aération) et un nouveau jeu de paramètres de l’ASM1 a pu être constitué. L’influence des propriétés des boues activées et des conditions d’opération sur les capacités de filtration des membranes reste encore l’objet de nombreuses recherches, généralement sur installations pilotes, et la modélisation dans ce domaine n’en est qu’à ses débuts. L’objectif de ce travail concernant la filtration membranaire a été de caractériser le système « membrane/boues » à travers l’étude des interactions entre les propriétés des boues, les conditions d’opération et les paramètres de la filtration (perméabilité membranaire et vitesse de colmatage) à comparer avec les résultats de la littérature scientifique. Les deux BAM étudiés ont montré des comportements et relations entre paramètres assez différents confirmant la complexité des interactions entre membrane, boues et conditions opératoires. / Membrane bioreactors (MBRs) are becoming increasingly popular for the treatment of municipal wastewater especially when land is limited or when the treatment requirements are high. Nevertheless, the operation of these plants and in particular the fouling of the membrane are still difficult to manage for the operators. Modelling is an efficient tool, which has already been successfully used on conventional activated sludge processes, for the operation and the understanding of the process using Activated Sludge Models (ASM). Biological treatment and membranes filtration capacity (fouling) are two aspects that can be modeled on MBRs. In this work, three full-scale plants were investigated and one of them was chosen for the ASM1 calibration. The usual methodology was adapted to the MBR specificities and to the modeled wastewater treatment plant in particular (wastewater fractionation, oxygen calibration) and a new set of ASM1 parameters was estimated. The influence of the sludge properties and the operating conditions on the membrane filtration capacity is still the subject of numerous studies, generally on pilot-scale MBRs, and modelling is in its early stages. The objective of this work regarding membrane filtration was to characterize the “membrane/sludge” system by studying the interactions between the sludge properties, the operating conditions and the filtration parameters (membrane permeability and fouling rate) and to compare them with the results from the literature. The two studied MBRs showed quite different behaviors and correlations between parameters, validating the statement that the interactions between membranes, sludge and operating conditions are very complex.
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Effet de la variabilité du fractionnement de la pollution carbonée sur le comportement des systèmes de traitement des eaux usées par boues activées / Effect of the variability of fractionation of carbonaceous pollution on the behaviour of the systems of treatment of waste water by activated sludgeLourenço da Silva, Mario do Carmo 03 July 2008 (has links)
Une méthode miniaturisée de fractionnement de la Demande Chimique en Oxygène (DCO) dans les eaux usées a été développée pour vérifier une possible variabilité à court terme de ce fractionnement et son influence sur le comportement des installations d’épuration par boues activées. Des tests de biodégradabilité, en réacteur fermé, ont été effectués avec des échantillons moyens horaires de temps sec (24h) provenant de deux stations d’épuration urbaines. Les analyses réalisées ont concerné la DCO totale et soluble, la Demande Biologique en Oxygène, les matières sèches et en suspension, l’ammonium et ont été complétées par des analyses spectrales (UV-visible et fluorescence). Globalement, en accord avec les données de la littérature, les fractions biodégradables sont les plus importantes en terme de concentration. Une variabilité journalière du fractionnement a été observée, sans qu’il soit possible de dégager des tendances particulières indiquant la prééminence de telle ou telle fraction. L’effet de la variabilité du fractionnement a été testé en boucle ouverte en utilisant un schéma classique d’épuration du carbone et de l’azote dans un simulateur de référence, le Benchmark Simulation Model 1. Les simulations ont permis de vérifier l’importance de la variabilité du fractionnement de la DCO sur une station d’épuration. Les concentrations en DCO dans l’effluent sont affectées par le rapport entre la fraction biodégradable et inerte, mais restent dans une limite acceptable par rapport aux normes de rejet. La situation est différente et plus délicate pour les rejets en matières azotées car ils sont proches des limites fixées par la réglementation / A miniaturized method has been developed for the fractionation of Chemical Oxygen Demand (COD) in wastewater in order to assess its variability and its effects on the behaviour of wastewater treatment plants by activated sludge. Biodegradability tests have been performed in batch reactor on daily composite samples grabbed by dry weather with a 1h sampling interval. The method has been applied on samples from two urban wastewater treatment plants. The samples were analysed for total and soluble COD, Biological Oxygen Demand, turbidity, total suspended solids and N-NH3. UV-visible and fluorescence spectra have also been collected. It has been observed, as in literature, that the biodegradable fractions are the most significant ones in terms of concentration. A variability of the fractionation during the day has been observed, although it was not possible to determine definite tendencies for particular fractions. In order to evaluate the effect of the variability of the fractionation, the Benchmark Simulation Model n°1 has been used. The sensibility analysis has been performed in open loop. The simulations allowed verifying the impact of the variability of the fractionation on a treatment plant based on a classical setup for the treatment of carbon and nitrogen. The COD concentrations of the plant effluent are affected by the ratio between the biodegradable fraction and the non-biodegradable one, although staying in an acceptable limit according to the discharge limits. The same is not true for the nitrogen, which are close to these limits
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Calibration of a dynamic model for the activated sludge process at Henriksdal wastewater treatment plantHellstedt, Cajsa January 2005 (has links)
<p>För att simulera aktivslamprocessen på ett reningsverk krävs en dynamisk modell som realistiskt beskriver processen. 1987 kom IWA, International Water Association med ASM1, Activated Sludge model no. 1 som fortfarande är den mest använda modellen för att beskriva denna process. I detta examensarbete har ASM1 används för att beskriva aktivslamprocessen på Henriksdals reningsverk i Stockholm. Arbetet har utförts som en del i ett europeiskt projekt, HIPCON (Holistic Integrated Process CONtrol) på IVL, Svenska Miljöinstitutet AB.</p><p>Arbetet har gått ut på att ta fram en modell som realistiskt beskriver aktivslamprocessen och eftersedimenteringen. För att göra detta har en referensmodell i MATLAB/Simulink använts som grund och byggts om för att likna processen vid Henriksdal. Denna modell i Simulink använder ASM1 för att beskriva aktivslamprocessen. Eftersedimenteringen modelleras med en massbalansmodell där sedimenteringshastigheten beskrivs av en dubbelexponentiell sedimenteringsfunktion. Både ASM1 och sedimenteringsfunktionen använder en mängd olika parametrar för att beskriva processerna och dessa måste kalibreras fram för den process som skall modelleras. Aktivslamprocessen är en biologisk process som beror på en mängd yttre och inre faktorer och är unik för varje reningsverk. Därför finns det inte något enkelt sätt att kalibrera en modell på och information för det enskilda reningsverket i fråga måste tas fram. I detta arbete har två mätkampanjer utförts på Henriksdal för att få mätserier till kalibrering och validering samt information om avloppsvattnets sammansättning. Litteraturstudier har också genomförts för att få information om vilka parametervärden som är av störst intresse för modellen samt i vilket område varje parameter kan förväntas finnas.</p><p>Arbetet har sedan gått ut på att efter riktlinjer för kalibrering funna i litteraturen ta fram en modell som så realistiskt som möjligt beskriver processen på Henriksdal. Först genomfördes en kalibrering med medelvärden för att hitta jämviktstillstånd och därmed en stabil modell på länge sikt. Utifrån den modellen utfördes sedan en dynamisk kalibrering för att få en modell som beskriver även kortsiktiga och snabba förändringar. Till sist utfördes en validering för att kontrollera om modellen fungerar även för en dataserie som ej använts vid kalibrering. Den framtagna modellen fungerade mycket bra för att modellera medelvärden på lång sikt. För snabba förändringar verkade modellen ligga fel i tiden och troligtvis var den reella uppehållstiden kortare än den teoretiska och bidrar till sämre modellanpassning.</p> / <p>To simulate the activated sludge process at a wastewater treatment plant a dynamic model that describes the process is needed. In 1987 IWA, International Water Association presented ASM1, Activated Sludge Model No.1 which still is the most widely used model for this process. In this thesis the ASM1 has been used to describe the activated sludge process. The work is a part of a European project, HIPCON (Holistic Integrated Process CONtrol) at IVL, Swedish Environmental Research Institute.</p><p>The main objective of the work was to calibrate a model that realistically describes the activated sludge process and secondary sedimentation at Henriksdal wastewater treatment plant in Stockholm. A benchmark model in MATLAB/Simulink was used as a base and rebuilt and extended to fit the process of Henriksdal. In the model ASM1 is used to describe the activated sludge process. The settler is modelled with a mass balance model where the settling velocity is described by a double exponential function. The parameters used in both models have to be calibrated to fit the wastewater treatment plant. To find information about Henriksdal two measuring campaigns were performed to provide data for calibration and validation and to gather information about the composition of the incoming wastewater. From this data a model was developed and calibrated for the process at Henriksdal. After calibration the obtained model worked very well for modelling average values but did not adjust quite as well to fast dynamic changes.</p>
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Analyse et optimisation du traitement de l'azote par boues activées à basse températureChoubert, Jean-Marc 20 September 2002 (has links) (PDF)
L'objectif principal de ce travail a porté sur l'optimisation du dimensionnement et de la gestion des installations de traitement des eaux usées par boues activées fonctionnant à basse température (10-12°C) et soumise à une contrainte de traitement poussé sur l'azote. Dans ce but, nous avons étudié la faisabilité de la nitrification à des charges massiques stabilisées supérieures à 0.1 kgDBO5.(kgMVS.j)-1. Le fonctionnement d'une installation pilote alimentée par un effluent synthétique, puis par un effluent urbain réel, a été étudié pour différentes charges massiques stabilisées à une température de 11 +/- 1°C. Les résultats très détaillés acquis en continu sur deux périodes de six mois ont suggéré le rôle et la hiérarchie des facteurs influençant la capacité de nitrification. Ils ont permis d'adapter l'outil de simulation dynamique Activated Sludge Model n°1 (ASM1). La double démarche expérimentale et numérique mise en oeuvre a permis de dégager les rôles des conditions de fonctionnement (âge des boues, charge volumique en azote, durée de présence d'oxygène) et des propriétés de l'effluent à traiter (ratios caractéristiques, part des différentes fractions) sur les performances de traitement de l'azote et sur la composition de la boue. Les valeurs limites des paramètres de gestion (charge massique maximale, durée d'aération journalière), permettant à différentes configurations d'installation (bassin unique, réacteur avec zone d'anoxie en tête) de respecter une concentration en azote total inférieure à 10 mgN/L dans le rejet, ont pu être dégagées. Des stratégies de gestion dans le cas de variations de flux importantes en entrée d'installation (cas des zones touristiques de montagnes) ont pu être évaluées (fonctionnement à charge massique variable par adaptation de la durée d'aération, ou bien utilisation d'un bassin d'aération à volume variable).
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Calibration of a dynamic model for the activated sludge process at Henriksdal wastewater treatment plantHellstedt, Cajsa January 2005 (has links)
För att simulera aktivslamprocessen på ett reningsverk krävs en dynamisk modell som realistiskt beskriver processen. 1987 kom IWA, International Water Association med ASM1, Activated Sludge model no. 1 som fortfarande är den mest använda modellen för att beskriva denna process. I detta examensarbete har ASM1 används för att beskriva aktivslamprocessen på Henriksdals reningsverk i Stockholm. Arbetet har utförts som en del i ett europeiskt projekt, HIPCON (Holistic Integrated Process CONtrol) på IVL, Svenska Miljöinstitutet AB. Arbetet har gått ut på att ta fram en modell som realistiskt beskriver aktivslamprocessen och eftersedimenteringen. För att göra detta har en referensmodell i MATLAB/Simulink använts som grund och byggts om för att likna processen vid Henriksdal. Denna modell i Simulink använder ASM1 för att beskriva aktivslamprocessen. Eftersedimenteringen modelleras med en massbalansmodell där sedimenteringshastigheten beskrivs av en dubbelexponentiell sedimenteringsfunktion. Både ASM1 och sedimenteringsfunktionen använder en mängd olika parametrar för att beskriva processerna och dessa måste kalibreras fram för den process som skall modelleras. Aktivslamprocessen är en biologisk process som beror på en mängd yttre och inre faktorer och är unik för varje reningsverk. Därför finns det inte något enkelt sätt att kalibrera en modell på och information för det enskilda reningsverket i fråga måste tas fram. I detta arbete har två mätkampanjer utförts på Henriksdal för att få mätserier till kalibrering och validering samt information om avloppsvattnets sammansättning. Litteraturstudier har också genomförts för att få information om vilka parametervärden som är av störst intresse för modellen samt i vilket område varje parameter kan förväntas finnas. Arbetet har sedan gått ut på att efter riktlinjer för kalibrering funna i litteraturen ta fram en modell som så realistiskt som möjligt beskriver processen på Henriksdal. Först genomfördes en kalibrering med medelvärden för att hitta jämviktstillstånd och därmed en stabil modell på länge sikt. Utifrån den modellen utfördes sedan en dynamisk kalibrering för att få en modell som beskriver även kortsiktiga och snabba förändringar. Till sist utfördes en validering för att kontrollera om modellen fungerar även för en dataserie som ej använts vid kalibrering. Den framtagna modellen fungerade mycket bra för att modellera medelvärden på lång sikt. För snabba förändringar verkade modellen ligga fel i tiden och troligtvis var den reella uppehållstiden kortare än den teoretiska och bidrar till sämre modellanpassning. / To simulate the activated sludge process at a wastewater treatment plant a dynamic model that describes the process is needed. In 1987 IWA, International Water Association presented ASM1, Activated Sludge Model No.1 which still is the most widely used model for this process. In this thesis the ASM1 has been used to describe the activated sludge process. The work is a part of a European project, HIPCON (Holistic Integrated Process CONtrol) at IVL, Swedish Environmental Research Institute. The main objective of the work was to calibrate a model that realistically describes the activated sludge process and secondary sedimentation at Henriksdal wastewater treatment plant in Stockholm. A benchmark model in MATLAB/Simulink was used as a base and rebuilt and extended to fit the process of Henriksdal. In the model ASM1 is used to describe the activated sludge process. The settler is modelled with a mass balance model where the settling velocity is described by a double exponential function. The parameters used in both models have to be calibrated to fit the wastewater treatment plant. To find information about Henriksdal two measuring campaigns were performed to provide data for calibration and validation and to gather information about the composition of the incoming wastewater. From this data a model was developed and calibrated for the process at Henriksdal. After calibration the obtained model worked very well for modelling average values but did not adjust quite as well to fast dynamic changes.
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Modellering och simulering av aktivslamprocessen vid Ekebyverket i Eskilstuna / Modeling and simulation of the activated sludge process at Ekeby WWTP in EskilstunaFalk, Wilma January 2020 (has links)
This work has been done with Ramboll Water, in cooperation with Eskilstuna Energi & Miljö (EEM), where the activated sludge process at Ekeby wastewater treatment plant (WWTP) has been themodeling object. The simulation study, using Sumo, shows that the nitrogen reduction using a separate digester supernatant treatment can be at most 3,7 mg/l, or 17 %, over a year when the maximum degree of treatment is assumed to be 90 %. With respect to the new emission requirements for Ekeby WWTP that starts in 2022, a 60 % degree of removal of the nitrogen in the supernatant is enough with unchanged population. With the 90 % nitrogen removal some room for a higher influent load might be possible. Business integration is elaborated applying quantitative and qualitative growth, learning and exploitation paired with model and model tool capability and a matrix combining assignment types and model tool functionality.Further studies in form of process capability and dynamic simulation is proposed.
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Process simulation for a small-scale poultry slaughterhouse wastewater treatment plantNdeba, Nganongo Lionnel Neddy Aymar January 2018 (has links)
Thesis (Master of Environmental Management)--Cape Peninsula University of Technology, 2018. / Fresh water is a renewable resource, but it is also finite, especially given environmental
impacts from anthropogenic activities. Globally, there are countless signs that untreated
industrial discharge into fresh watercourses is one of the main causes of ecosystem
degradation. Poultry slaughterhouse wastewater (PSW) amongst the main pollutants of fresh
water sources. In recent years, the world’s pre-eminent researchers have developed
innovative wastewater treatment processes to treat the large quantity of wastewater
generated as well as to manage the environmental health concerns arising from PSW
discharged into the environment. Furthermore, increasing wastewater treatment capital costs
and the implementation of increasingly rigorous government legislation to mitigate
environmental pollution whilst minimizing fresh water source contamination, requires that
wastewater such as PSW, be adequately treated prior to discharge.
In order to assist the small-scale poultry producers in South Africa (SA), process simulation
for a small-scale poultry slaughterhouse wastewater treatment plant was proposed using
Sumo Wastewater treatment plant (WWTP) simulation software. Sumo is an innovative and
most versatile wastewater simulation package on the market. The simulator is capable of
modelling treatment plants of unlimited complexity, focusing largely on Biochemical oxygen
demand (BOD), Chemical oxygen demand (COD), nitrogen and phosphorus removal; with
digester, and side streams design options, being available. Considering the possible
advantages in modelling and ongoing studies of implementing wastewater treatment to
increase water management, anaerobic digestion of high strength wastewater such as PSW,
warranted this research study. Model development from the simulation included the
evaluation of numerous design options to assist small scale poultry producers, to have a
variety of designs to choose from in their PSW WWTP designs.
With the aid of Sumo, two models were designed in this study, namely a single-stage and a
two-stage anaerobic digestion without a recycle. The PSW used as feed was obtained from
a local poultry slaughterhouse (Western Cape, South Africa). Both model designs predicted
the reduction of the organic matter (COD, BOD5) total suspended solids (TSS), and volatile
suspended solids (VSS) in the PSW. The digester for the single stage anaerobic digestion
system modelled was set to operate at steady state for 150 days under mesophilic
temperature (35 ˚C) with a solid retention time (SRT) of 25 days. The COD, TSS, VSS and
BOD removal efficiencies reached a maximum of 64%, 77%, 84%, and 94%, respectively, at
an organic load rate (OLR) of 143.6 mg COD/L/day. A minute increase in the ammonia
(NH3) and phosphate (PO3-
4) concentration was observed once the simulation was
completed.
As for the two-stage anaerobic digestion system, both digesters were set to perform at
mesophilic temperatures (35 ˚C) and a SRT of 13 days in the first digester and 25 days in
the subsequent digester. The two-stage anaerobic digestion showed better performance in
comparison to the single-stage anaerobic digestion system. The COD, TSS, VSS and BOD5
removal efficiencies reached a maximum of 69%, 79%, 85%, and 96%, respectively, at an at
an OLR of 143.6 mg COD/L/day. A similar trend regarding phosphate and ammonia removal
was noticed in the two-stage anaerobic digestion, suggesting a tertiary treatment system to
be in place for further treatment.
Although, the two-stage anaerobic digestion demonstrated adequate performance, for the
purpose of this study, the single-stage was the process recommended for PSW treatment,
as it is less costly and will be suitable for small scale poultry producers; albeit biogas
production is much higher when digesters are connected in series.
The PSW treatment modelling for this study was successfully employed with the resultant
effluent being compliant with the City of Cape Town (CCT) wastewater and industrial effluent
by-law discharge limits. Although, both the PO3-
4 and NH3 were suggested to require further
monitoring.
Therefore, the poultry slaughterhouse from which the PSW was obtained will be able to
safely discharge the treated wastewater proposed in this research into local water bodies,
i.e. rivers in the Western Cape, SA; however, the treated PSW will not be suitable for re-use
as process water.
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