Spelling suggestions: "subject:"coving bed"" "subject:"boving bed""
11 |
Industrial wastewater treatment with anaerobic moving bed biofilm reactordi Biase, Alessandro January 2016 (has links)
The overall goal of the thesis was to develop and optimize the moving bed biofilm reactor technology under anaerobic conditions. The thesis work was divided into two different series of experiments. Hence, at first, the reactor start-up on synthetic substrate was evaluated and it was proven that the anaerobic moving bed biofilm reactor technology could successfully treat concentrated wastewater. Subsequently, a study on Fort Garry Brewery wastewater was conducted to optimize the process for a typical North American industrial wastewater. The aim was successfully achieved and a potential design to treat Fort Garry Brewery wastewater was developed. The anaerobic moving bed biofilm reactor was found to be capable in treating brewery wastewater with potential savings to the industry paying surcharges for discharging wastewater over the city sewer bylaw limits. / October 2016
|
12 |
Etude du couplage hydrodynamique/adsorption : application au lit mobile simulé / Study of the coupling of hydrodynamics and adsorption : application to simulated moving bed processesFangueiro Gomes, Leonel 06 November 2015 (has links)
Modèle monodimensionnel de type Piston-Dispersion. Le terme de dispersion axiale englobe alors toutes les imperfections de l'écoulement : injection des fluides non homogène dans l’espace et étalée dans le temps, effet de parois, et enfin volumes morts derrière les obstacles noyés dans le tamis (poutres, conduites...) dans le cas des Lits Mobiles Simulés. Cette représentation, quoique très simpliste, s'avère généralement suffisante tant que l’étalement des fronts de concentration est d'abord induit par les limitations au transfert externe, interne (macro/microporeux) et par la thermodynamique du système. Par contre, lorsque l’adsorbant employé présente d’excellentes performances de transfert, une approche aussi simple s'avère extrêmement risquée. En effet, les phénomènes dispersifs associés à l’adsorbant (transfert et thermodynamique) et à l’hydrodynamique ont des contributions de même ordre de grandeur sur la dispersion des fronts de concentration. Dans ce cas, une description plus réaliste de l'écoulement est requise afin de mieux appréhender son effet sur les performances de séparation.Dans ce contexte, l’objectif de ce projet de thèse est de mettre en place une méthodologie pour prendre en compte ces phénomènes hydrodynamiques lors de l’extrapolation d’un procédé de séparation par adsorption. Pour cela, nous proposons une étude du couplage entre les phénomènes hydrodynamiques et le phénomène d’adsorption. / Hydrodynamics inside industrial Simulated Moving Bed (SMB) adsorption columns can be complex due to the presence of internal distribution devices, free flow chambers and heterogeneous injections. These have to be taken into account in SMB numerical models to scale-up purposes. In the present thesis, a CFD approach is adopted as an intermediate step to develop a 1D model simple enough to be used for cyclic SMB simulations while being able to represent realistic hydrodynamics. This model results from the interpretation of the moments of the fluid age distribution, transported by CFD according to the method developed by Liu and Tilton (2010) that allows to estimate the degree of mixing (Liu, 2011) of the adsorption columns. The resulting 1D model consists in the two examples provided by Zwietering (1959) of a completely segregated system and a maximum mixedness system. This model is able to reproduce the residence time distribution of the CFD model of an adsorption column, while being representative of the internal flow patterns. This results in a good representation of the coupling of adsorption and hydrodynamics by the 1D model. When integrated in a SMB simulator and compared to the traditionally used dispersed plug flow model, the new 1D model demonstrates that for most of the adsorption column geometries considered a detailed hydrodynamic description is mandatory. Such detailed hydrodynamic description is even more important when employing adsorbents with better mass transfer performances than those currently used for the p-xylene purification, which is expected in the upcoming years.
|
13 |
Utvärdering av den biologiska reningen av processavloppsvattnet vid GE Healthcare i Uppsala / An evaluation of the biological wastewater treatment at GE Healthcare in UppsalaFridlund, Malin January 2005 (has links)
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. 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. 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). 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 40oC during the construction period. This could have a negative influence of the organic reduction. Individual measured temperatures of 38oC 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. / 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. 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. 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. 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 CODlöst/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.
|
14 |
Modeling Nitrogen Transformations in a Pilot Scale Marine Integrated Aquaculture SystemMccarthy, Brian 01 January 2013 (has links)
Integrated aquaculture systems (IAS) are a type of recirculating aquaculture systems (RAS) where the wastewater is treated and returned to the fish tanks. The important difference between the two is that in an IAS, wastes from the aquaculture component are recovered as fertilizer to produce an agricultural product whereas in an RAS, waste organics, nutrients and solids are treated and discharged. A pilot marine IAS at Mote Aquaculture Research Park in Sarasota, FL was studied for this project. Water quality monitoring, measurements of fish health and growth rates of fish and plants were performed over a two-year period to determine the effectiveness of the system in producing fish and plant products and removing pollutants. The goal of this portion of the project was to develop, calibrate and evaluate a model of the system, to understand the nitrogen transformations within the Mote IAS and to investigate other potential configurations of the Mote IAS.
The model was divided into the various compartments to simulate each stage of the system, which included fish tanks, a drum filter for solids removal, and moving bed bioreactor (MBBR) for nitrification and disinfection. A solids tank after the drum filter was used to store the drum filter effluent slurry, which was then divided between three treatment processes: a geotube, a sand filter followed by a plant bed, and a plant bed alone. Nitrogen species modeled were particulate organic nitrogen (PON), dissolved organic nitrogen (DON), ammonium and nitrate. Of the physical components of the IAS, models of the MBBR and the two plant raceways included physical, chemical and biological nitrogen transformation processes. The sand filter, solids tank and geotube models were simple mass balances, incorporating factional removals of each species based on the observed data. Other variables modeled included temperature, dissolved oxygen, volatile suspended solids and chemical oxygen demand concentrations. The model was built in a computer program, STELLATM, to simulate the Mote IAS.
The model calibration involved experimental, literature and calibrated parameters. Parameters were adjusted until the model's output was a best fit to the observed data by minimizing the sum of the squared residuals. During the sensitivity analysis, two model parameters caused large variations in the model output. The denitrifier constant caused the most variation to the model's output followed by the denitrifier fraction of volatile suspended solids.
Of the removal processes, denitrification was the largest nitrogen removal mechanism from the model, accounting for 59% and 55% of the nitrogen removed from the south and north plant raceways respectively. Plant and soil uptake represented only 0.2% of the overall nitrogen removal processes followed by 0.1% by sedimentation.
Finally, the model was used to investigate other treatment designs if the Mote IAS was redesigned. The first option involved a geotube and one plant raceway in series to treat the solid waste while the second option did not have a geotube, but two plant raceways. The first option was the most effective at removing nitrogen while the second was as effective as the original system and would cost less.
|
15 |
Systematic optimization and experimental validation of simulated moving bed chromatography systems for ternary separations and equilibrium limited reactionsAgrawal, Gaurav 21 September 2015 (has links)
Simulated Moving Bed (SMB) chromatography is a separation process where the components are separated due to their varying affinity towards the stationary phase. Over the past decade, many modifications have been proposed in SMB chromatography in order to effectively separate a binary mixture. However, the separation of multi-component mixtures using SMB is still one of the major challenges. Although many different strategies have been proposed, previous studies have rarely performed comprehensive investigations for finding the best ternary separation strategy from various possible alternatives. Furthermore, the concept of combining reaction with SMB has been proposed in the past for driving the equilibrium limited reactions to completion by separating the products from the reaction zone. However, the design of such systems is still challenging due to the complex dynamics of simultaneous reaction and adsorption.
The first objective of the study is to find the best ternary separation strategy among various alternatives design of SMB. The performance of several ternary SMB operating schemes, that are proposed in the literature, are compared in terms of the optimal productivity obtained and the amount of solvent consumed. A multi- objective optimization problem is formulated which maximizes the SMB productivity and purity of intermediate eluting component at the same time. Furthermore, the concept of optimizing a superstructure formulation is proposed, where numerous SMB operating schemes can be incorporated into a single formulation. This superstructure approach has a potential to find more advantageous operating scheme compared to existing operating schemes in the literature.
The second objective of the study is to demonstrate the Generalized Full Cycle (GFC) operation experimentally for the first time, and compare its performance to the JO process. A Semba OctaveTM chromatography system is used as an experimental SMB unit to implement the optimal operating schemes. In addition, a simultaneous optimization and model correction (SOMC) scheme is used to resolve the model mismatch in a systematic way. We also show a systematic comparison of both JO and GFC operations by presenting a Pareto plot of the productivity achieved against the desired purity of the intermediate eluting component experimentally.
The third objective of the study is to develop an simulated moving bed reactor (SMBR) process for an industrial-scale application, and demonstrate the potential of the ModiCon operation for improving the performance of the SMBR compared to the conventional operating strategy. A novel industrial application involving the esterification of acetic acid and 1-methoxy-2-propanol is considered to produce propylene glycol methyl ether (PMA) as the product. A multi-objective optimization study is presented to find the best reactive separation strategy for the production of the PMA product. We also present a Pareto plot that compares the ModiCon operation, which allows periodical change of the feed composition and the conventional operating strategy for the optimal production rate of PMA that can be achieved against the desired conversion of acetic acid.
|
16 |
Modification of a Moving Bed Biofilm Reactor(MBBR) due to radically changed process conditions : A case study of Kvarnsveden paper millJohansson Macedo, Liv May January 2018 (has links)
Papermaking process require large amounts of energy and water; therefore, pulp and paper mills can be potentially very polluting. The wastewater resulting from the papermaking process must be carefully managed as it is very rich in dissolved organic matter and contain compounds that make it difficult to treat. MBBR technology emerged as a possibility to increase the treatment capacity and to make more compact treatment systems designed to remove high organic loads, since in addition to having biomass in suspension as the activated sludge process, also has biomass adhered to plastic supports. This research was commissioned by Stora Enso Kvarnsveden and emerged in need of a bioreactor modification due to reduction of the wastewater load after the closure of PM11 in 2013 and PM8 in 2017. An evaluation of the performance of bioreactors is necessary with possible results to only run one bioreactor in the future and save energy. For performance analysis, two weeks of measurements were performed, one with the two bioreactors running at the same time and one with only K150 reactor running, trying to simulate what happens if one of them is stopped. Analysis of the main operating parameters of the MBBR system were evaluated during this research. As result, it was recommended an action to remove the excess of adhered biomass and an increase of the filling rating to 50%, in order to optimize TOC reduction.
|
17 |
Separação cromatografica quiral do o,p'-diclorodifenildicloroetano (mitotano) em fase estacionaria quiral O,O'bis[4-terc-butilbenzoil]-N,N'dialil-L-tartadiamida / Chiral chromatographic separation of the o,p'-dichlorodiphenyldichloroethane (mitotane) using chiral stationary phase O,O'-bis{4-terc-butylbenzoyl]-N,N'-diallyl-L-tartardiamideDias, Raquel Macedo 23 April 2007 (has links)
Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T16:18:50Z (GMT). No. of bitstreams: 1
Dias_RaquelMacedo_M.pdf: 1158217 bytes, checksum: 17fc0268f6869b95e17b301e65d69e9c (MD5)
Previous issue date: 2007 / Resumo: O mitotano (o,p?-diclorodifenildicloroetano) é um fármaco utilizado no tratamento de carcinoma adrenocortical. Ele é comercializado na forma racêmica, ou seja, na proporção 1:1 dos seus enantiômeros R e S. A influência da quiralidade da molécula sobre seu efeito farmacológico ainda não foi estudada. Portanto, a separação dos enantiômeros é importante para testes biológicos comparativos de efeitos colaterais. Este trabalho foi desenvolvido com o intuito de estudar a separação deste fármaco pela técnica de cromatografia líquida de alta eficiência utilizando coluna recheada com a fase estacionária quiral O,O?-bis[4-tercbutilbenzoil]-N,N?-dialil-L-tartardiamida. Diferentes combinações de fase móvel foram testadas e os melhores resultados foram obtidos com hexano/acetato de etila na proporção 95/5 (v/v). Experimentos de pulsos com soluções diluídas do traçador e dos enantiômeros do mitotano foram realizados variando a vazão de fase móvel e a temperatura do sistema. Foram determinados as porosidades do sistema, os parâmetros cromatográficos, os dados de equilíbrio, coeficientes de dispersão axial e parâmetros de transferência de massa. Os resultados mostraram separação satisfatória, com número de pratos superando 9000 e fatores de separação na ordem de 1,13. Os valores dos coeficientes de Henry foram maiores que a unidade para ambos os enantiômeros, sendo que o enantiômero mais retido R-(+)-mitotano, apresentou maior afinidade pela coluna quiral. Valores de km superiores a 300 min-1 revelaram baixo efeito dos fenômenos de transferência de massa e consequentemente predomínio dos efeitos termodinâmicos (energia entálpica superior -10 kJ/mol para os enantiômeros). Experimentos a altas concentrações foram realizados com a finalidade de se determinar às isotermas pelo método da análise frontal e também os cromatogramas sob estas condições. Para a concentração da mistura até 16 g/L as isotermas mostraram um bom ajuste ao modelo de Langmuir. A partir da separação em batelada determinaram-se as regiões de separação dos enantiômeros para um sistema cromatográfico contínuo do tipo leito móvel simulado para diferentes concentrações de alimentação da mistura racêmica. Avaliaram-se as variáveis desempenho (consumo de solvente e produtividade) no sistema contínuo e compararam-se com as obtidas em separações em batelada. Melhores resultados foram obtidos para um sistema contínuo do tipo leito móvel simulado / Abstract: Mitotane (o, p'-dichlorodiphenyldichloroethane) is a drug used in the treatment of adrenocortical carcinoma. It is marketed in the racemic form, proportion 1:1 of their R and S enantiomers. The influence of the molecule quirality on its pharmacology effect was not studied yet. For this reason, this separation is important for comparative biological tests of collateral effects. This work was developed with intention to study the separation of this drug via liquid chromatography using columns packed with the chiral stationary phase, O,O?-bis[4-terc-butylbenzoyl] - N, N' - diallyl-L-tartardiamide. Different combinations of mobile phase was tested and better results were achieved with hexane/ethyl acetate in ratio 95/5 (v/v). Pulses experiments with diluted solutions of the inert and the enantiomers were accomplished at different flow rates and temperature. The system porosities, chromatographic parameters, equilibrium constants, axial dispersion and mass transference parameters were obtained. The results showed satisfactory separation, with number of plates overcoming 9000 and separation factors in the order of 1,13. The values of Henry coefficients were greater than one for both enantiomers, the most retained was R (+) -mitotane, and it presented greater affinity for the chiral column. The overall mass transfer coefficient achieved values higher than 300 min-1, demonstrating low mass transfer effect rates and consequently a prevalence of the thermodynamic effects (enthalpy energy greater than -10 kJ/mol for the enantiomers). Experiments in overload conditions were realized in order to determining the isotherms using the method of the frontal analysis as well the chromatograms under these conditions. For the concentration of the mixture smaller than 16 g/L the isotherms showed a good adjusted to the Langmuir model. The separation regions for a chromatographic continuous system like simulated moving bed were determined with different feed concentrations. This permits the comparison of the performance parameters using the continuous system and batch ones / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química
|
18 |
MBBR Produced Solids: Particle Characteristics, Settling Behaviour and Investigation of Influencing FactorsArabgol, Raheleh 23 March 2021 (has links)
The separation of solids from biological wastewater treatment is an important step in the treatment process, as it has a significant impact on effluent water quality. The moving bed biofilm reactor (MBBR) technology is a proven upgrade or replacement wastewater treatment system for carbon and nitrogen removal. However, a challenge of this technology is the characteristics of the effluent solids that results in their poor settlement; with settling being the common method of solids removal. The main objective of this research is to understand and expand the current knowledge on the settling characteristics of MBBR produced solids and the parameters that influence them. In particular, in this dissertation, the impacts are studied of carrier types, biofilm thickness restraint design of carriers, and varying carbonaceous loading rates on MBBR performance, biofilm morphology, biofilm thickness, biofilm mass, biofilm density, biofilm detachment rate, solids production, particle size distribution (PSD) and particle settling velocity distribution (PSVD).
With this aim, three MBBR reactors housing three different carrier types were operated with varying loading rates. In order to investigate the effect of carrier geometrical properties on the MBBR system, the conventional, cylindrically-shaped, flat AnoxK™ K5 carrier with protected voids was compared to two newly-designed, saddle-shaped Z-carriers with the fully exposed surface area. Moreover, the AnoxK™ Z-200 carrier was compared to the AnoxK™ Z-400 carrier to evaluate the biofilm thickness restraint design of these carriers, where the Z-200 carrier is designed for greater biofilm thickness-restraint. The Z-200 carrier is designed to limit the biofilm thickness to the level of 200 µm as opposed to 400 µm for the Z-400 carrier. Finally, to investigate the effects of varying carbonaceous loading rates on system removal performance, biofilm characteristics and solids characteristics, further analyses were performed at three different loading rates of 1.5 to 2.5 and 6.0 g-sBOD/m2·d in steady-state conditions. The PSD and the PSVD analyses were combined to relate these two properties. A settling velocity distribution analytical method, the ViCAs, was applied in combination with microscopy imaging and micro-flow imaging to investigate the relation of PSD and settling behaviour of MBBR produced particles.
The obtained results have indicated that the carrier type significantly impacted the MBBR performance, biofilm, and particle characteristics. As such, the K5 carrier MBBR system demonstrated a statistically significantly higher carbonaceous removal rate and efficiency (3.8 ± 0.3 g-sBOD/m2·d and 59.9 ± 3.0% sBOD removal), higher biofilm thickness (281.1 ± 8.7 μm), higher biofilm mass per carrier (43.9 ± 1.0 mg), lower biofilm density (65.0 ± 1.5 kg/m3), lower biofilm detachment rate (1.7 ± 0.7 g-TSS/ m2·d) and hence lower solids production (0.7 ± 0.3 g-TSS/d) compared to the two Z-carriers. The Z-carriers' different shape exposes the biofilm to additional shear stress, which could explain why the Z-carriers have thinner and denser biofilm, resulting in higher solids production and lower system performance in comparison with K5. Moreover, the carrier type was also observed to impact the particle characteristics significantly. PSD analysis demonstrated a higher percentage of small particles in the Z-carrier system effluent and hence a significantly lower solids settling efficiency. Therefore, the solids produced in the K5 reactor have shown enhanced settling behaviour, consisting of larger particles with faster settling velocities compared to Z-carriers.
This dissertation also investigated the effects of restraint biofilm thickness on MBBR performance by comparing the Z-200 biofilm thickness-restraint carrier to the Z-400 carrier. No significant difference was observed in removal efficiency, biofilm morphology, biofilm density, biofilm detachment rate, and solids production between the Z-200 to the Z-400 carriers. The PSD and the PSVD analyses did not illustrate any significant difference in the particles’ settling behaviour for these two biofilm thickness restraint carriers, indicating that the biofilm thickness-restraint carrier design was not a controlling factor in the settling potential of MBBR produced solids.
Finally, this research studied the effect of varying loading rates and demonstrated a positive, strong linear correlation between the measured sBOD loading rate and the removal rate, indicating first-order BOD removal kinetics. The biofilm thickness, biofilm density and biofilm mass decreased when the surface area loading rate (SALR) was increased from 2.5 to 6.0 g-sBOD/m2·d. The solids retention time (SRT) was also shown to decrease by increasing the SALR, where the lowest SRT (1.7 ± 0.1 days) was observed at the highest SALR, with the highest cell viability (81.8 ± 1.7%). Significantly higher biofilm detachment rate and yield were observed at SALR 2.5, with the thickest biofilm and a higher percentage of dead cells. Consequently, a higher fraction of larger and rapidly settling particles was observed at SALR of 2.5 g-sBOD/m2·d, which leads to a significantly better settling behaviour of the MBBR effluent solids.
This study expands the current knowledge of MBBR-produced particle characteristics and settling behaviour. A comprehensive understanding of the MBBR system performance and the potential influencing factors on the MBBR produced solids, particle characteristics, and their settleability will lead to optimized MBBR design for future pilot- and full-scale applications of the MBBR.
|
19 |
Study on Process Performance and Evaluation of Dala Vatten’s Two Municipal Wastewater Treatment Plants.Amatya, Anjali January 2016 (has links)
Dala Vatten AB has been operating two municipal wastewater treatment plant namely Gagnef wastewater treatment plant and Tällberg wastewater treatment plant since 1970’s and 1950’s respectively in Dalarna, middle of Sweden. These both traditional treatment plants have been updated with continuous and intermittent aerated biological treatment facilities: Moving bed biofilm reactor (MBBR) in 2012 and 2007 respectively. Recently, more detailed process performance and evaluation of both plants is required focusing on energy consumption. The objective of this master thesis is thus to investigate the opportunities in reducing energy consumption from both plants to save operation cost, identify the opportunities for chemical saving, if possible reduce the excess sludge so produced from the plant and potential optimization of the process for its plant’s sustainability. The laboratory study was made in May and August, 2015 with grab sampling and flow proportional sampling method. The analysation was carried out with several wastewater parameters: BOD7, COD, TOC, TP, NH4-N and TN with Hach Lange analysing method. Results showed that both continue and intermittent aerated plants have higher process performance with lower effluent organic (BOD7, COD) and TP loading to the recipient. Gagnef WWTP with continuous aeration has demonstrated an excessive use of chemical, sludge production and high-energy consumption by the blower serving MBBR during the studied period. By contrast, Tällberg WWTP with intermittent aeration has proved to be successful in terms of lower energy consumption by the blower serving the MBBR but failed to show improved specific energy efficiency for each pollutant load during the studied period. The recommendation in improvising energy saving and saving operation cost at both treatment plants was put forward.
|
20 |
Study on one-stage Partial Nitritation-Anammox process in Moving Bed Biofilm Reactors: a sustainable nitrogen removal.Bertino, Andrea January 2011 (has links)
In the last decade, several novel and cost-effective biological nitrogen removal technologies have been developed. The discovery of anaerobic ammonium oxidation (Anammox), about 15 years ago, has resulted in new opportunities for research and development of sustainable nitrogen removal systems. Compared to conventional nitrification/denitrification, Anammox eliminates necessity of external organic carbon source, has a smaller production of excess sludge, reduces energy demand for aeration (up to 60-90%) and CO2 emissions (up to 90%). Systems based on Anammox can be of great help to comply with stricter wastewater discharge regulations and reduce environmental problems caused by nutrients discharges (e.g. eutrophication). This thesis investigates the partial nitritation/Anammox in one stage system under oxygen limited condi-tions (also called CANON or Deammonification) and with the Moving Bed Biofilm Reactor (MBBR™) technology. Anammox process coupled with partial nitritation can be particularly suitable to treat ammo-nium-rich wastewater with low content of biodegradable organic matter, such as the reject water from dewatering of digested sludge, which is usually recirculated back to the main stream of wastewater treat-ment plants, accounting for the 15-20% of the total nitrogen load. Partial nitritation/Anammox process was successfully tested on a pilot plant scale for four months at 25°C, in a 200 L Continuous Stirred Tank Reactor (CSTR), filled with 40% of Kaldnes media (model K1). At an Ammonium Surface Load (ASL) of 3.45 gN m-2d-1, the removal rate was about 2.85 gN m-2d-1. Removal efficiencies of 95%, 85% and 83% were respectively achieved for NH4+-N, inorganic nitrogen, and Total Nitrogen (TN). Bacteria activity was followed by batch tests such as Specific Anammox Activity (SAA), Oxygen Uptake Rate (OUR) and Nitrate Uptake Rate (NUR), which revealed an increase in activi-ty for Nitrosomonas and Anammox bacteria within the biofilm. Dissolved oxygen concentration in the bulk liquid was a crucial parameter, whereas pH and conductivity turned out to be two useful monitoring tools. Two laboratory-scale reactors were previously run for two months each, in order to evaluate the one-stage partial nitritation/Anammox process with a lower ASL. One reactor was fed with diluted reject water, whereas the other one treated the effluent from UASB (Up-flow Anaerobic Sludge Blanket) reactor after sand filtration. Fairly good efficiency (>75%) were reached but, however, in the last case the low ammo-nium nitrogen load could represent a problem for a stable full-scale installation and long-term growth of Anammox bacteria. Some suggestions for full-scale implementation and further research are proposed in the last chapter of this master thesis.
|
Page generated in 0.0931 seconds