No description available.

This dissertation presents an analysis of two aspects of the chromatographic separation process known as Simulated Moving Bed (SMB) chromatography. The first aspect is system design, and the second is improving computer simulations to generate heuristics for choosing operational modes. For the past 15-20 years, there has been a surge of interest in the use of Simulated Moving Bed systems for the chromatographic separation of chemicals¹. A wide variety of methods, nomenclatures, and conventions have been adopted over the years²⁻⁴, as teams from different backgrounds adopt and improve on the SMB technology. This work presents a unifying discussion of the two major design methods, Triangle Theory and Standing Wave Design, used in the SMB field. We provide the complete computer code required to execute both design methods. A sample problem is worked, which demonstrates the novelty and ease of use that such tools provide. Mathematica was chosen for the implementation of these design methods, because of its strong symbolic analysis capabilities, and simplicity of creating interfaces for new users. We present derivations of the classic Langmuir results in Mathematica, and proceed to extend those implementations. When analytic solutions are impossible, we use Mathematica's numerical methods. This work also develops a distributed computing tool known as ChromRunner which allows large numbers of detailed numerical simulations to be run simultaneously. The motivations and benefits of this approach are discussed alongside implementation details. We apply the distributed computing system to two separate SMB separations in order to optimize them, as well as determine heuristics governing their operational modes. We wrote ChromRunner in C#, and took advantage of Visual Studio's Entity Framework to create the database backend. The user interface for this software was created using Microsoft's "Windows Presentation Foundation" (WPF) technologies. / Ph. D.

Biofilm systems such as the moving bed biofilm reactor (MBBR) are finding increased application in wastewater treatment. One important process that governs MBBRs and yet is poorly understood is the rate of biofilm detachment. The detachment of cells from biofilm surfaces controls both the accumulation of biofilm and the quantity of biomass that is suspended in the bulk liquid phase. This changing balance of attached and suspended cells, in this thesis named the biosolids dynamics, can impact the efficacy of MBBRs. The goal of this research was to investigate how the biosolids dynamics are influenced by process changes relevant to applied wastewater treatment systems and suggest new routes to reactor design and optimization. To achieve this goal, the work addresses three separate but interconnected lines of inquiry. First, multivariate analysis (Principal Component Analysis, Partial Least Squares) was used to examine 2 years of historical data from an MBBR operating at a Canadian pulp mill in order to identify key process variables, perform process diagnostics, and act as a predictive tool. Secondly, the effect of calcium concentration on biofilm structure, microbiology and reactor performance was investigated in four laboratory-scale MBBRs operated at a range of calcium concentrations (1 to 300 mg/L Ca2+). It was found that above a threshold calcium concentration between 1-50 mg/L, MBBR biofilms were observed to be thicker with greater density, contain larger anoxic regions adjacent to the carrier substratum, have more proteinaceous EPS, and have altered microbial community structure. The results suggest an important role for calcium that should be considered in the design and operation of MBBRs. In the final line of inquiry, a diffusion-reaction biofilm model was adapted to represent the key processes of the MBBR. The model was found to simulate average trends observed in the lab-scale experiments allowing for quantification of the detachment rate. Transient periods of reactor starvation were also simulated by introducing a novel metabolic state function to account for down-regulation of metabolism as a result of starvation. This approach was found to accurately simulate starvation response when coupled with detachment expressions that were growth-dependant.

The application of membrane bioreactors (MBRs) to wastewater treatment is increasing due to their ability to operate at high biomass concentrations and to deliver effluents of high quality. The major challenges associated with the application of MBRs is fouling which can shorten the useful life of the membrane, increase in the amount of energy consumed, and the cost for membrane cleaning. The main reasons for fouling are the deposition of solids as a cake layer, pore plugging by colloidal particles, adsorption of soluble compounds and biofouling. Fouling is a particular problem for activated sludge membrane bioreactors (AS-MBRs) since this process deals with liquors having a high concentration of total solids as well as dissolved compounds such as extracellular polymeric substances (EPS). The combination of a moving bed biofilm reactor and a membrane reactor (MBBR-MR) has significant potential. It may be considered as a compact wastewater treatment process which can compensate for the drawbacks of AS-MBRs. Readily biodegradable COD is removed in the MBBR while particulate matter is separated by the membrane. To further reduce the membrane fouling the effects of adding an intermediate coagulation stage was investigated critically on membrane fouling. The present study includes an overall assessment of the performance of a combined MBBR-MR system, based on the chemical oxygen demand (COD) removal efficiency and membrane fouling mechanism. The required test runs were conducted using pilot-scale MBBR and ultra filtration membrane. The pilot MBBR had a working volume of 1.8 m3 with a 60% carrier fill fraction. The MBBR was operated with loading rate of 78 ± 21 g/m2/d (HRT of 4 h). The ultra-filtration was spiral wound and composed of polyethersulfone (PES) with a pore size of 0.03 microns. The MBBR feed was obtained from a final treated wastewater effluent in a food processing plant located in SW Ontario. In this research, ferric chloride was also employed as a coagulant and influences of different coagulant doses and permeate fluxes on membrane fouling were studied. Based on the experimental results, it was found that the combination of MBBR with membrane filtration can produce a constant high quality permeate that is appropriate for water reuse purposes. The composition analysis of permeate showed that the stream is free of suspended solids and the average COD turns to 75 ± 25 mg/l. In addition, the MBBR had a SCOD removal of 76% ± 7% which is considered as a reasonable efficiency for a single reactor. Operating the membrane without adding coagulant caused rapid fouling in a short time period and the Trans Membrane Pressure (TMP) reached the maximum allowable pressure of 10 psi. However, addition of coagulant was found to decrease the fouling of the membrane as well as increasing the filtration time. The extent of the pre-coagulation effect on membrane fouling was found to strongly depend on the dosage of the coagulant and the MBBR effluent characteristics. A coagulant dose of 400 mg/l with a permeate flux of 7.6 LMH performed the best at reducing membrane fouling. Colloidal fouling was found to be a significant fouling mechanism at low coagulant dose (e.g. 200 mg/l), while cake formation appeared to be mainly responsible for fouling at higher coagulant doses. Permeate flux was found to have a significant effect on the fouling of the membrane. The presence of colloidal matters at low fluxes and TSS at higher fluxes were responsible for fouling of the membrane by blocking the pores and formation of the cake layer on the membrane surface, respectively. Then later addition of Dissolved Air Flotation (DAF) inside the factory had a noticeable effect on wastewater characteristics and consequently on fouling of the membrane. A 22% and 31% improvement in TCOD and TSS in the wastewater was observed leading to reduction in the fouling.

Biofilm systems such as the moving bed biofilm reactor (MBBR) are finding increased application in wastewater treatment. One important process that governs MBBRs and yet is poorly understood is the rate of biofilm detachment. The detachment of cells from biofilm surfaces controls both the accumulation of biofilm and the quantity of biomass that is suspended in the bulk liquid phase. This changing balance of attached and suspended cells, in this thesis named the biosolids dynamics, can impact the efficacy of MBBRs. The goal of this research was to investigate how the biosolids dynamics are influenced by process changes relevant to applied wastewater treatment systems and suggest new routes to reactor design and optimization. To achieve this goal, the work addresses three separate but interconnected lines of inquiry. First, multivariate analysis (Principal Component Analysis, Partial Least Squares) was used to examine 2 years of historical data from an MBBR operating at a Canadian pulp mill in order to identify key process variables, perform process diagnostics, and act as a predictive tool. Secondly, the effect of calcium concentration on biofilm structure, microbiology and reactor performance was investigated in four laboratory-scale MBBRs operated at a range of calcium concentrations (1 to 300 mg/L Ca2+). It was found that above a threshold calcium concentration between 1-50 mg/L, MBBR biofilms were observed to be thicker with greater density, contain larger anoxic regions adjacent to the carrier substratum, have more proteinaceous EPS, and have altered microbial community structure. The results suggest an important role for calcium that should be considered in the design and operation of MBBRs. In the final line of inquiry, a diffusion-reaction biofilm model was adapted to represent the key processes of the MBBR. The model was found to simulate average trends observed in the lab-scale experiments allowing for quantification of the detachment rate. Transient periods of reactor starvation were also simulated by introducing a novel metabolic state function to account for down-regulation of metabolism as a result of starvation. This approach was found to accurately simulate starvation response when coupled with detachment expressions that were growth-dependant.

The cost of pretreatment process for saccharification from biomass and the cost of dilute ethanol purification are significant components of the overall cost for fuel grade ethanol production through fermentation or other biological routes. This work focuses on developing optimal designs of dilute ethanol purification process and the new acid hydrolysis technology for the production of fermentable sugars from biomass where the overarching goal is to reduce the cost of ethanol production from biomass. In this thesis, the ethanol separation process with the reverse osmosis membrane pretreatment is developed to reduce separation cost and energy consumption especially when the feed is dilute. In addition, the new solid phase reactive separation system for biomass saccharification via acid hydrolysis is proposed. This new process is applied for both dilute and concentrated acid hydrolysis where the goal is to increase sugar yield and to reduce byproduct formation. The reaction kinetics of the concentrated acid hydrolysis is investigated through batch experiment. All of these use optimization approaches for seeking the best process designs and for parameter estimations.

The application of membrane bioreactors (MBRs) to wastewater treatment is increasing due to their ability to operate at high biomass concentrations and to deliver effluents of high quality. The major challenges associated with the application of MBRs is fouling which can shorten the useful life of the membrane, increase in the amount of energy consumed, and the cost for membrane cleaning. The main reasons for fouling are the deposition of solids as a cake layer, pore plugging by colloidal particles, adsorption of soluble compounds and biofouling. Fouling is a particular problem for activated sludge membrane bioreactors (AS-MBRs) since this process deals with liquors having a high concentration of total solids as well as dissolved compounds such as extracellular polymeric substances (EPS). The combination of a moving bed biofilm reactor and a membrane reactor (MBBR-MR) has significant potential. It may be considered as a compact wastewater treatment process which can compensate for the drawbacks of AS-MBRs. Readily biodegradable COD is removed in the MBBR while particulate matter is separated by the membrane. To further reduce the membrane fouling the effects of adding an intermediate coagulation stage was investigated critically on membrane fouling. The present study includes an overall assessment of the performance of a combined MBBR-MR system, based on the chemical oxygen demand (COD) removal efficiency and membrane fouling mechanism. The required test runs were conducted using pilot-scale MBBR and ultra filtration membrane. The pilot MBBR had a working volume of 1.8 m3 with a 60% carrier fill fraction. The MBBR was operated with loading rate of 78 ± 21 g/m2/d (HRT of 4 h). The ultra-filtration was spiral wound and composed of polyethersulfone (PES) with a pore size of 0.03 microns. The MBBR feed was obtained from a final treated wastewater effluent in a food processing plant located in SW Ontario. In this research, ferric chloride was also employed as a coagulant and influences of different coagulant doses and permeate fluxes on membrane fouling were studied. Based on the experimental results, it was found that the combination of MBBR with membrane filtration can produce a constant high quality permeate that is appropriate for water reuse purposes. The composition analysis of permeate showed that the stream is free of suspended solids and the average COD turns to 75 ± 25 mg/l. In addition, the MBBR had a SCOD removal of 76% ± 7% which is considered as a reasonable efficiency for a single reactor. Operating the membrane without adding coagulant caused rapid fouling in a short time period and the Trans Membrane Pressure (TMP) reached the maximum allowable pressure of 10 psi. However, addition of coagulant was found to decrease the fouling of the membrane as well as increasing the filtration time. The extent of the pre-coagulation effect on membrane fouling was found to strongly depend on the dosage of the coagulant and the MBBR effluent characteristics. A coagulant dose of 400 mg/l with a permeate flux of 7.6 LMH performed the best at reducing membrane fouling. Colloidal fouling was found to be a significant fouling mechanism at low coagulant dose (e.g. 200 mg/l), while cake formation appeared to be mainly responsible for fouling at higher coagulant doses. Permeate flux was found to have a significant effect on the fouling of the membrane. The presence of colloidal matters at low fluxes and TSS at higher fluxes were responsible for fouling of the membrane by blocking the pores and formation of the cake layer on the membrane surface, respectively. Then later addition of Dissolved Air Flotation (DAF) inside the factory had a noticeable effect on wastewater characteristics and consequently on fouling of the membrane. A 22% and 31% improvement in TCOD and TSS in the wastewater was observed leading to reduction in the fouling.

No description available.

S'han creat les eines necessàries per a estudiar la viabilitat de dur a terme la separació de mescles de dos i tres components basats en un mètode de separació en continu tipus SMB. Amb aquesta finalitat, s'ha creat un sistema per al disseny ràpid i econòmic de separadors SMB que permet simular el comportament d'una columna qualsevol integrada en un sistema SMB. Aquest sistema, està constituït per una sola columna cromatogràfica que pot treballar en qualsevol de les quatre zones en què es pot dividir un SMB.El sistema de control de l'instrument permet simular cicles complets de separadors SMB. A més, el programa també permet treballar amb separacions formalment binàries o ternàries, en conformacions de SMB de 4, 6 i 8 columnes i combinació d'elles agrupades en 4 zones de treball. El sistema també integra un programa de simulació numèrica i optimització de separadors SMB. La combinació del programa i el sistema de disseny de SMB permet establir la variació de la concentració de cada substància amb el temps podent així determinar: el nombre de columnes per zona, el temps de canvi de cada columna, el cabal d'operació a cada zona i la concentració de cada substància per cada sortida de l'SMB.Per tal de verificar el correcte funcionament de l'equip complet s'ha dut a terme la separació de dos components, fenol i triclorofenol, determinant-ne les condicions òptimes de separació. Tot i que la retenció entre aquestes dues substàncies és molt similar, el prototipus ha permès estudiar el comportament de la unitat SMB complerta. També s'ha estudiat la separació del p-aminofenol i l'o-aminofenol com a part integrant del procés de fabricació del paracetamol i se n'han trobat les condicions òptimes d'operació. En treballar amb aquest procés s'ha buscat la màxima puresa del p-aminofenol en detriment de la puresa de l'o-aminofenol aconseguint una puresa de p-aminofenol a la sortida refinat del 97%. Finalment, i des del punt de vista del canvi d'escala, s'han determinat els valors de la longitud no utilitzada de rebliment i del coeficient global de transferència de matèria per tal de poder extrapolar els resultats del prototipus a escala industrial. / Se han creado las herramientas necesarias para estudiar la viabilidad de desarrollar separaciones de mezclas de 2 y 3 componentes basados en un método de separación en continuo tipo SMB. Con esta finalidad se ha creado un sistema para el diseño rápido y económico de separadores SMB que permite simular el comportamiento de una columna cualquiera integrada en un sistema SMB. Este sistema está constituido por una única columna cromatográfica que puede trabajar en cualquiera de las cuatro zonas en que se puede dividir un SMB.El sistema de control del instrumento permite simular ciclos completos de separadores SMB. Además, el programa también permite trabajar con separaciones formalmente binarias o ternarias, en conformaciones de SMB de 4, 6 y 8 columnas y combinación de ellas agrupadas en 4 zonas de trabajo. El sistema también integra un programa de simulación numérica y optimización de separadores SMB. La combinación del programa y el sistema de diseño de SMB permite establecer la variación de la concentración de cada sustancia con el tiempo pudiendo así determinar: el número de columnas por zona, el tiempo de cambio de cada columna, el caudal de operación en cada zona y la concentración de cada sustancia por cada salida del SMB. Para verificar el correcto funcionamiento del equipo completo se ha separado una mezcla de dos compuestos, fenol y triclorofenol, determinando las condiciones óptimas de separación. Aunque la retención entre estas dos sustancias es muy similar, el prototipo ha permitido estudiar el comportamiento de la unidad SMB completa. También se ha estudiado la separación del p-aminofenol y el o-aminofenol como parte integrante del proceso de fabricación del paracetamol y se han determinado las condiciones óptimas de operación. Al trabajar con este proceso se ha buscado la máxima pureza del p-aminofenol con menoscabo de la pureza del o-aminofenol consiguiendo una pureza de p-aminofenol a la salida de refinado del 97%. Finalmente se han determinado los valores de la longitud de lecho no utilizada y del coeficiente global de transferencia de materia para extrapolar los resultados del prototipo a escala industrial. / The necessary tools to study the viability of developing separations of mixtures of 2 and 3 components using a continuous method like the SMB have been developed. A fast and non-expensive system to design such separations has been developed. This system can simulate the behaviour of a single column integrated in the SMB. This system is composed by a single column capable to work in every one of the four zones into which an SMB can be divided. The control system gives the possibility of simulate complete cycles of an SMB separator. In addition the program also can work with binary or ternary separations, in SMB conformations of 4, 6 and 8 columns and its combinations grouped together in 4 working zones. The system also integrates a numerical simulation and optimization program of SMB separators. The combination of program and SMB design system establishes the concentration of each substance within the time. It gives the following parameters: the number of columns per zone, the column switch time, the flow in each zone and the concentration at the SMB outlet. In order to check the correct operation of the whole unit the separation of phenol and trichlorophenol have been done determining the best operation conditions. However the retention of this substances is very similar, the prototype has studied the complete separation. It also has been studied the separation of p-aminophenol and o-aminophenol as a part of the sysntesis process os paracetamole and the best separation condition have been stablished. While working with this process the maximum purity of p-aminophenol has been searched. The purity of p-aminophenol at the raffinate outlet is about 97%. Finally the values of unused bed lenght and overall mass transfer coefficient have been calculated to extrapolate the results to the industrial scale.

<p>GE Healthcare operates in Uppsala (Sweden) and develops systems, equipments and medium to purify medical substances. Discussions with the local authority concerning planed far-reaching changes and upgrades of the biological process techniques for sewage management, aroused the question about revising the terms of permit for the activity. Therefore it seemed necessary to evaluate a newly installed biological process technique, which is the background of this thesis. The evaluated biological treatment process was built in 2003 and consists of a biological reactor filled with moving bed carriers with a high surface area for biological growth. At the time of the project the biological wastewater treatment plant consisted of a flow equalization facility and two following parallel biological processes; a biological reactor with moving bed carriers and a tower trickling filter.</p><p>The aim of this thesis was to survey the function of the biological reactor with respect to the reduction of organic matter. Further to clarify which circumstances that have a negative effect on the organic reduction. During the three forthcoming years, an extensive reconstruction of the biological wastewater treatment facility will be accomplished. During the construction period the flow equalization will be very limited. Therefore an emission forecast with respect to organic matter was performed comprising the construction period during the years 2005, 2006 and 2007. This to estimate the safety margin to the emission standard during the construction period.</p><p>Several parameters were surveyed during the project, water temperature, pH, plural nutrition elements, flow, oxygen concentration, suspended solids, organic load and microbial activity. At two occasions, the parameters were extensively studied during a 24-hour period respectively. Two capacity experiments were performed in order to evaluate the organic reduction at different organic loads. The obtained results together with an estimation regarding the organic load performed by AB Ångpanneföreningen were used for the emission forecast. The forecast considered two cases, operation with and without dosage of a flow with high organic content from the local solvent recycling facility (called T10-dosage).</p><p>According to the forecast, the emission standard will be fulfilled during an average month regarding the organic load. This without T10-dosage and with an average reduction of 55 %. To fulfill the standard during a month with maximum organic load, a reduction of 65 and 75 % will be required in the cases without and with T10-dosage respectively. The organic reduction is negatively effected by lasting loads of 7 kg CODfilt/m3 or higher, or by a great increase of the load in a short period of time. Sporadic peaks regarding the organic load appeared to have temporary or no negative effects on the reduction. Flow variations during evenings, nights and weekends caused variations in the organic load with negative effect of the reduction rate. The oxygen concentration in the biological reactor has a conclusive significance of the reduction rate, a lower concentration than 2 mg/l affects the reduction rate in a negative way. The buffering capacity in the biofilm reactor showed to work excellently, the pH value varied between 6.8 and 8.9. There is an immediate risk of temperatures over 40^oC during the construction period. This could have a negative influence of the organic reduction. Individual measured temperatures of 38^oC did not have a negative effect on the reduction rate. The amount of suspended solids varied a lot in the outflow from the biological reactor and will continue to do so during the construction period.</p> / <p>GE Healthcare bedriver sin verksamhet i Uppsala vilken består av att utveckla system, utrustning och media för att rena läkemedelssubstanser. Vid diskussion med Uppsala kommuns VA- och avfallskontor väcktes frågan angående omprövning av tillståndet för verksamheten. Diskussionerna rörde planerade processförändringar och kompletteringar av bolagets biologiska processavloppsvattenrening. Av den anledningen ansågs det nödvändigt att utreda en för företaget ny processteknik för processavloppsvatten, vilket är bakgrunden till detta examensarbete. Den utvärderade processtekniken är en biofilmreaktor innehållande ett rörligt bärarmaterial med en stor skyddad yta för biologisk tillväxt. Biofilmreaktorn togs i drift under hösten år 2003 och därmed bestod det lokala reningsverket förenklat sett av en utjämningsanläggning följd av två parallella biosteg, ett biotorn med konventionell stationär biobädd över vilken processavloppsvatten spreds samt en biofilmreaktor med rörligt bärarmaterial.</p><p>Syftet med examensarbetet var att kartlägga biofilmreaktorns funktion med avseende på reduktion av organiskt material. Vidare att klargöra vid vilka förhållanden reduktionsgraden har påverkats negativt. Under de tre kommande åren skall en stor om- och tillbyggnad av reningsverket genomföras. Förändringen kommer att medföra att utjämningsvolymen blir mycket begränsad under ombyggnadsperioden. Av den anledningen var ytterligare ett syfte med examensarbetet att utföra en utsläppsprognos med avseende på organiskt material för åren 2005 till och med 2007. Detta för att bedöma säkerhetsmarginalen till utsläppsvillkoret under ombyggnadsperioden.</p><p>Examensarbetet realiserades genom att kartlägga parametrarna organisk belastning, organisk reduktion, vattentemperatur, pH, närsalter, flöde, koncentration löst syre, suspenderad substans samt mikrobiell aktivitet. Därutöver utfördes två kapacitetsförsök för att kartlägga den organiska belastningens inverkan på reduktionen. Vid det ena försöket skapades en högre organisk belastning genom att successivt öka flödesbelastningen över biofilmreaktorn. Vid det andra försöket doserades en delström (kallad T10-dosering) innehållande rester från den lokala lösningsmedelsåtervinningen med stort organiskt innehåll. Därtill utfördes två dygnsprovtagningar för att kartlägga ett flertal parametrars dygnsvariationer. Den framtagna utsläppsprognosen baserades på en belastningsprognos utförd av AB Ångpanneföreningen samt den i arbetet kartlagda reduktionen av organiskt material vid olika belastningar. Prognosen omfattar två fall, med eller utan T10-dosering.</p><p>Enligt utsläppsprognosen kommer utsläppsvillkoret inte att överskridas under åren 2005 till och med 2007. Detta gäller vid en för året genomsnittlig månad avseende belastning utan T10-dosering och med en genomsnittlig organisk reduktionsgrad på 55 %. Under en månad med maximal belastning krävs 65 % reduktion och 75 % med T10-dosering. Kapacitetsförsöken visade att reduktionsgraden påverkades negativt vid en varaktig belastning överstigande 7 kg COD_löst/m3 samt vid kraftiga belastningsökningar. Tillfälliga belastningstoppar hade endast kortvarig eller ingen negativ inverkan på reduktionen. Höga flöden under dagtid och låga flöden under nätter och helger orsakade variationer i den organiska belastningen, vilket hade en negativ inverkan på reduktionen. När koncentrationen löst syre i biofilmreaktorn understeg 2 mg/l påverkades mikroorganismerna negativt och därmed även reduktionen. Buffertkapaciteten i biofilmreaktorn var god under den studerade tidsperioden och pH-värdet varierade mellan 6,5 och 8,8. Under ombyggnadsperioden föreligger en stor risk för att vattentemperaturen kan bli för hög i biofilmreaktorn vid ett flertal tillfällen. Enstaka uppmätta temperaturtoppar på 38°C påverkade dock inte reduktionen negativt. I biofilmreaktorns utgående vatten varierade mängden suspenderad substans kraftigt, vilket även kommer att gälla under ombyggnadsperioden.</p>