Tesi sul tema "Membrane bioreactor"
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1
Ntwampe, Seteno Karabo Obed. "Multicapillary membrane bioreactor design". Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/897.
Testo completoAbstract (sommario):
Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2005The white rot fungus, Phanerochaete chrysosporium, produces enzymes, which are capable of degrading chemical pollutants. It was detennined that this fungus has multiple growth phases. The study provided infonnation that can be used to classify growth kinetic parameters, substrate mass transfer and liquid medium momentum transfer effects in continuous secondary metabolite production studies. P. chrysosporium strain BKMF 1767 (ATCC 24725) was grown at 37 QC in single fibre capillary membrane bioreactors (SFCMBR) made of glass. The SFCMBR systems with working volumes of 20.4 ml and active membrane length of 160 mm were positioned vertically. Dry biofilm density was determined by using a helium pycnometer. Biofilm differentiation was detennined by taking samples for image analysis, using a Scanning Electron Microscope at various phases of the biofilm growth. Substrate consumption was detennined by using relevant test kits to quantify the amount, which was consumed at different times, using a varying amount of spore concentrations. Growth kinetic constants were detennined by using the substrate consumption and the dry biofilm density model. Oxygen mass transfer parameters were determined by using the Clark type oxygen microsensors. Pressure transducers were used to measure the pressure, which was needed to model the liquid medium momentum transfer in the lumen of the polysulphone membranes. An attempt was made to measure the glucose mass transfer across the biofilm, which was made by using a hydrogen peroxide microsensor, but without success.
2
Jones, Franck Anderson. "Modelling of novel rotating membrane bioreactor processes". Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/16345.
Testo completoAbstract (sommario):
Previous membrane researches undertaken over the years to develop general deadend filtration models made use of an approach that combined all three classical fouling mechanisms, namely, pore blocking, pore constriction and cake filtration. More recently researchers have modified and adapted this modelling approach for a cross flow side-stream membrane bioreactor (MBR) system. Literature also reveals that there have been numerous recent experimental studies conducted on rotating membrane bioreactor (RMBR) systems. Some of these studies have resulted in the creation of RMBR models of the membrane fouling process as well. However, simulation and modelling of the fouling in RMBRs is still a nascent topic to date due to poor understanding and great complexity of the system hydrodynamics involved. Even when models are developed, they are either too complex to be useful at operational level, or not comprehensive enough to express all possible operational scenarios. In many cases they are simply too difficult to calibrate and thus ending up being more suited as research tools rather than for direct process control. As such, further research is required in this area. The research reported in this thesis consists of the development and validation of a RMBR system fouling model that incorporates all three classical fouling mechanisms. This thesis work is divided into two main sections. On top of a literature review that thoroughly describes the background theory and general information on MBRs along with their state of the art, the first section of the thesis also explains the specific methodologies used to accomplish all the main tasks carried out in this research work. The first step of these methodologies involves the setting-up of a rotating MBR system process based upon the FUV-185-A15R Flexidisks membrane module that was developed by Avanti Membrane Technology (USA). This system was used to collect the majority of the data used in this thesis. Since some of these data outputs were compared against non-rotating MBR systems, a similar setting-up process for a bespoke static square MBR system was carried out as well. Using synthetic wastewater in conjunction with activated sludge, mixed liquor suspended solids in both MBR system bioreactors were increased in levels over time to desired levels (i.e. by periodic excess sludge wasting). Trans-membrane pressure (TMP)-stepping fouling data was then acquired from operations of these membrane ultrafiltration processes. This data was obtained by measuring the flux decline or TMP increase. Following data collection, a dynamic fouling model for this RMBR system was then created in Matlab (using the Genetic Algorithm function). To do this, hydrodynamic regimes such as air scouring and rotating shear effects along with all the three classical fouling mechanisms were included in the mathematical fouling model that was created from first principles. For the purpose of comparison, a similar fouling model was created without incorporating the rotational effects for the static square MBR system. This included modelling of the hydrodynamics as well. Finally, both these models were validated and calibrated using the data that were collected from both laboratory-based MBR systems. The second phase of the thesis explores the numerous outputted results produced via model simulations which were then discussed and analysed in great detail. Results from this research indicate that the mathematical models give a decent portrayal and description of the fouling mechanisms occurring within a rotating MBR system. It was found that the rotational mechanisms in terms of fouling prevention accounted for only twelve percent of cake removal with the rest being accomplished through the air scouring mechanism. However, it was found that although the slowly rotating spindle induced a weak crossflow shear, it was still able to even out cake build up across the membrane surface, thus reducing the likelihood of localised critical flux being exceeded, which would lead to dramatic loss of flux. Furthermore, when compared against the static MBR system, the study concluded that a rotating MBR system could increase the flux throughput by a significant amount. In conclusion, RMBR systems appear to represent alternative viable solutions when compared against the traditional static MBR systems that currently dominate the industrial and municipal marketplace. In future, RMBR systems may become the systems of first choice once there is a better understanding of the rotational processes, and once research and design into this sector broadens. Future study areas should thus focus on: whether the forces acting on an activated sludge particle during rotation have a significant effect on the fouling or the shear hydrodynamic regimes; whether activated sludge and benchmark models could be created for rotating MBRs whilst including the shear effects and hydrodynamic regimes; whether model predictive control using these developed RMBR models would enhance efficiency gains within an operational plant; and, whether the real measured soluble microbial products (SMP) concentrations could be used to create an even better SMP predictive model that accurately explains fouling behaviour.
3
Radocaj, Olgica. "Ethanol fermentation in a membrane bioreactor". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0015/MQ45840.pdf.
Testo completo
4
Germain, E. A. M. "Biomass effects on membrane bioreactor operations". Thesis, Cranfield University, 2004. http://dspace.lib.cranfield.ac.uk/handle/1826/11032.
Testo completoAbstract (sommario):
Diverse
operating parameters were investigated for their effects on biomass
characteristics, membrane fouling and aeration efficiency in submerged membrane
bioreactors (MBRS).
The characteristics of the solid phase of the biomass were affected by the biomass
state
(unstabilised, stabilising and stabilised) and by the SRT and HRT, whereas the
characteristics of the liquid phase appeared to be more dependent on inuent
composition and strength. Under operating conditions at constant SRT and HRT, the
biomass characteristics reached their stabilised state aer 1.0±0.3 SRT.
The
impact of membrane aeration, permeate flux and biomass characteristics was
determined for biomass at unstabilised state and at stabilised state. A transitional
permeate flux was observed between 16.5 and 22 l.m`2.h`l, below which no significant
fouling was observed regardless of the permeate flux, membrane airflow velocity and
biomass characteristics. Above transitional flux, membrane fouling increased and was
affected
by the permeate flux, the membrane aeration velocity and parameters either
characterising the liquid or the solid phase of the biomass depending on the
carbohydrate concentration of the liquid phase.
A
comparison of ne and coarse bubble aeration efficiency for biomass at
unstabilised state and at several airflow rates established that ne bubble aeration was
more efficient in tem of oxygen transfer rate, but led to similar values to coarse
bubble aeration for ot-factor. The effects of airflow rate and biomass characteristics on
oxygen transfer coefficient and ot-factor were determined for biomass coming from
pilot and full scale submerged MBRS treating municipal and industrial wastewaters.
Solids concentrations (correlated to viscosity), COD concentration of the liquid phase,
carbohydrate concentration of the EPS and volumetric airflow rate were found to
affect the aeration efficiency parameters. A transitional solids concentration existed
around 15 g.L", above which low or no oxygen transfer occurred.
5
Du, Preez Ryne. "Development of a membrane immobilised amidase bioreactor system". Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1996.
Testo completo
6
Pavasant, Prasert. "Modelling of the extractive membrane bioreactor process". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266478.
Testo completo
7
Boontawan, Apichat. "A membrane bioreactor for biotransformation of terpenes". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413713.
Testo completo
8
Splendiani, Antonietta. "Biofilm control in an extractive membrane bioreactor". Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401883.
Testo completo
9
Mamo, Julian. "Assessment and optimisation of the operation of integrated membrane system for wastewater reclamation". Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/667844.
Testo completoAbstract (sommario):
The combination of two membrane technologies coupled together in series has become a standard technology when it comes to producing reclaimed water of high quality for potable reclamation or industrial applications. This combination of two membrane processes is referred to as integrated membrane systems (IMS). Despite the widespread experience gained utilizing such a process technology around the world, there are a number of aspects of the process technology which require further investigation including the fate of compounds of emerging concern (CEC), the control of N-Nitrosodimethylamine (NDMA) formation, the use of energy associated with the process and the total cost of producing the reclaimed water, and monitoring membrane integrity in RO treatment processes. The objective of this work was to further the knowledge in one aspect related to each of these four challenges and then bring each of these areas together in the discussion to understand whether proposing a decision support system for the online monitoring and operation of integrated systems would allow improvements to the current state-of-the-art.La combinació de dos tecnologies de membrana acoblades en sèrie ha esdevingut un tecnologia consolidada degut a la capacitat de produir aigua d’elevada qualitat i potencialment reutilitzable per aplicacions industrials com fins i tot per ser potabilitzada. Tot i l’elevada experiència adquirida en aquests processos combinats, encara hi ha aspectes del procés que calen una investigació més profunda que inclogui el coneixement sobre l’eliminació dels compostos emergents, el control de la formació de N-Nitrosodimetilamines (NDMA), l’ús de l’energia associada amb el procés incloent el cost total de produir l’aigua reutilitzable, i el seguiment de la integritat de la membrana en el tractament amb osmosi inversa (OI). L’objectiu d’aquest treball recau en avançar en el coneixement dels aspectes relacionats amb cada un dels quatre reptes esmentats, per aconseguir discutir de forma conjunta la millor forma d’integrar aquest nou coneixement adquirit proposant un sistema d’ajuda a la decisió pel control i seguiment de l’operació de sistemes integrats de membrana (SIM).
10
Deng, Shi. "Development of a coarse pore membrane bioreactor with in-situ membrane cleaning /". View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?EVNG%202007%20DENG.
Testo completo
11
Minervini, Mirko. "A membrane bioreactor for enzyme recovery from saccharification". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Cerca il testo completoAbstract (sommario):
The present work is part of a bigger project which, as a final goal, has the development and the optimization of a membrane integrated saccharification process for the production of corn based sugar syrups in Cargill plants. Nowadays, the starch saccharification process is mainly performed through a two steps batch bioreactor mediated by hydrolytic enzymes. First, a fast preliminary hydrolysation occurs, where the long polymeric starch chains are cut and of a maltodextrin mixture is produced. Then, the liquified starch is sent to a batch bioreactor where different hydrolytic enzymes, according to the final product type, complete the starch conversion into molecules at low degree of polymerization (DP). The optimisation idea is to use a membrane bioreactor to operate the saccharification in continuous mode, where the enzymes are separated from end products with the help of a selective ultrafiltration membrane. The process under investigation is an innovative technology with high potentiality which could allow not only to increase the reaction yield, but also to save on downstream costs. The Cargill plant of Castelmassa (RO) is taken as reference for this work, in particular, the dextrose line that produces highly concentrated sucrose syrups. Therefore, starting from the currently adopted plant set-up the best operative conditions for a hypothetical plant development with membrane bioreactors will be determined. The experimental work aimed at the optimisation of the membrane filtration stage was performed in the MEMLAB laboratories at DICAM, of the university of Bologna, using a 10 kDa membrane selected from a previous study. The optimisation of reaction conditions was performed in Castelmassa, using the real plant feed to the saccharification stage.
12
Hu, Alan Yung-Chih. "Anaerobic in-tank membrane bioreactor for wastewater treatment". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414422.
Testo completo
13
Ball, James. "Biotransformations operated in a two phase membrane bioreactor". Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362309.
Testo completo
14
Zsirai, Tamas. "Fouling and clogging in hollow fibre membrane bioreactor". Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8411.
Testo completoAbstract (sommario):
The sustainability of a large pilot-scale hollow fibre immersed membrane bioreactor (HF iMBR) has been investigated with specific reference to membrane surface fouling and membrane channel clogging. Studies were conducted at normal sludge solids concentration of around 8 g/L and were also extended to concentrations more associated with thickening processes (around 32 g/L). A review of mechanically- moved membranes was conducted with a view to exploring a low energy means of sustaining operation through suppressing clogging. Methods were devised to quantify the amount of clogged solids within the membrane fibre bundle, either through their separation and gravimetric analysis or in-situ gravimetic estimation of the clogged solids without their removal from the membrane HF bundle. Outcomes generally revealed clogging to be as important a contributor to suppression of permeability as fouling, the key differentiator being that chemical cleaning had no sustained impact on permeability recovery when clogging took place. It was further substantiated that the operating permeability of membranes, once they had been clogged, could not be returned to that of the preclogged state despite declogging (i.e. mechanical removal of the solids) followed by the repeated application of chemically-enhanced backwashing. This was attributed to membrane pore plugging. Cont/d.
15
Solomon, MS. "Membrane bioreactor production of lignin and manganese peroxidase". Thesis, Cape Technikon, 2001. http://hdl.handle.net/20.500.11838/901.
Testo completoAbstract (sommario):
Thesis (M.Tech-Chemical Engineering)--Cape Technikon, Cape Town, 2001The white-rot fungus (WRF), Phanerochaete chrysosporium, is a well known microorganism which produces ligninolytic enzymes. These enzymes can play a major role in the bioremediation of a diverse range of environmental aromatic pollutants present in industrial effluents. Bioremediation of aromatic pollutants using ligninolytic enzymes has been extensively researched by academic, industrial and government institutions, and has been shown to have considerable potential for industrial applications. Previously the production of these enzymes was done using batch cultures. However, this resulted in low yields of enzyme production and therefore an alternative method had to be developed. Little success on scale-up and industrialisation of conventional bioreactor systems has been attained due to problems associated with the continuous production of the pollutant degrading enzymes. It was proposed to construct an effective capillary membrane bioreactor, which would provide an ideal growing environment to continuously culture an immobilised biofilm of P; chrysosporium (Strain BKMF-1767) for the continuous production of the ligninolytic enzymes, Lignin(LiP) and Manganese(MnP) Peroridase. A novel membrane gradostat reactor (MGR) was shown to be superior to more conventional systems of laboratory scale enzyme production (Leukes et.al., 1996 and Leukes, 1999). This concept was based on simulating the native state ofthe WRF, which has evolved on a wood-air interface and involved irnmobilisng the fungus onto an externally skinless ultrafiltration membrane. The MGR however, was not subjected to optimisation on a laboratory scale. The gradostat reactor and concept was used in this work and was operated in the deadend filtration mode. The viability of the polysulphone membrane for cultivation of the fungus was investigated. The suitability of the membrane bioreactor for enzyme production was evaluated. The effect of microbial growth on membrane pressure and permeability was monitored. A possible procedure for scaling up from a single fibre membrane bioreactor to a multi-capillary system was evaluated. Results indicated that the polysulphone membrane was ideal for the cultivation of P chrysosporium, as the micro-organism was successfully immobi1ised in the macrovoids of the membrane resulting in uniform biofilm growth along the outside of the membrane. The production of Lignin and Manganese Peroxidase was demonstrated. The enzyme was secreted and then transported into the permeate without a rapid decline in activity. Growth within the relatively confined macrovoids of the membrane contributed to the loss of membrane permeability. A modified Bruining Model was successfully applied in the prediction of pressure and permeability along the membrane The study also evaluated the effect of potential1y important parameters on the production of the enzymes within the membrane bioreactor. These parameters include air flow (Ch concentration), temperature, nutrient flow, relative redox potential and nutrient concentrations A sensitivity analyses was performed on temperature and Ch concentration. The bioreactor was exposed to normal room temperature and a controlled temperature at 37°C. The reactors were then exposed to different O2 concentration between 21% and 99"10. It was found that the optimum temperature fur enzymes production is 3TJC. When oxygen was used instead of air, there was an increase in enzyme activity. From the results obtained, it was clear that unique culture conditions are required for the production of LiP and MnP from Phanerochaete chrysosporium. These culture conditions are essential fur the optimisation and stability of the bioreactor.
16
Singh, Shailendra. "Methodology for Membrane Fabric Selection for Pilot-Bioreactor". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1313078841.
Testo completo
17
RAO, PRASANNA. "TREATMENT OF ACID MINE DRAINAGE USING MEMBRANE BIOREACTOR". University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1006887417.
Testo completo
18
Trzcinski, Antoine Prandota. "Anaerobic membrane bioreactor technology for solid waste stabilization". Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/4358.
Testo completoAbstract (sommario):
In this study, a simulated Organic Fraction of Municipal Solid Waste (OFMSW) was treated inan anaerobic two-stage membrane process. The OFMSW feedstock was fed to a ten litre hydrolyticreactor (HR) where solid and liquid fractions were separated by a coarse mesh, whilethe leachate was fed to a three litre submerged anaerobic membrane bioreactor (SAMBR) within-situ membrane cleaning by biogas sparging beneath a flat sheet Kubota membrane. Theaim was to develop and optimize this two-stage process where the use of a membrane in bothreactors to uncouple the Solid and Liquid Retention Times (SRT and HRT) would allow us toimprove the current performances obtained with single stage designs. The Denaturing GradientGel Electrophoresis (DGGE) technique was used to monitor the microbial population in the reactorsand have a better understanding of the archaeal and bacterial distribution in a two-stageprocess. It was found that meshes with pore sizes of 10 microns and 150 microns were inappropriateto uncouple the SRT and HRT in the HR. In the former case, the mesh became clogged, whilein the latter case, the large pore size resulted in high levels of suspended solids in the leachatethat built up in the SAMBR. The most important parameter for Volatile Solids (VS) removal in theHR was the SRT. Maximum VS removals of 70-75% could be achieved when the SRT was equalto or greater than 50-60 days. This was achieved at a HRT of 9-12 days and an Organic LoadingRate (OLR) of 4-5 g VS.l-1.day-1.Increasing the SRT to beyond 100 days did not significantlyincrease the VS removal in the HR. However, at an OLR of 10 g VS.l-1.day-1 in the HR the SRThad to be reduced due to a build up of TS in the HR that impeded the stirring. Below 20 daysSRT, the VS removal reduced to between 30 and 40%. With kitchen waste as its main substrate,however, an OLR of 10 g VS.l-1.day-1 was achieved with 81% VS removal at 23 days SRT and1.8 days HRT.The SAMBR was found to remain stable at an OLR up to 19.8 g COD.l-1.day-1 at a HRT of0.4 day and at a SRT greater than 300 days, while the COD removal was 95%. However, theperformance at such low HRTs was not sustainable due to membrane flux limitations whenthe Mixed Liquor Total Suspended Solids (MLTSS) went beyond 20 g.l-1 due to an increase inviscosity and inorganics concentration. At 35 ?C the SAMBR was found to be stable (SCODremoval 95%) at SRTs down to 45 days and at a minimum HRT of 3.9 days. The SAMBRcould achieve 90% COD removal at 22 ?C at an OLR of 13.4 g COD.l-1.day-1 and 1.1 days HRT(SRT = 300 days).The DGGE technique was used to monitor the archaeal and bacterial diversity and evolutionin the HR and SAMBR with varying SRTs, HRTs, OLRs and temperatures in the biofilm andin suspension. Overall, it was found that stable operation and high COD removal correlatedwith a high bacterial diversity, while at the same time very few species (2-4) were dominant. Only a few dominant archaeal species were sufficient to keep low VFA concentrations in theSAMBR at 35 ?C, but not at ambient temperatures. It was found that some of the dominantspecies in the HR were hydrogenotrophic Archaea such as Methanobacterium formicicum andMethanobrevibacter while the other dominant species were from the genus Methanosarcinaor Methanosaeta. The presence of hydrogenotrophic species in the HR could be fostered byreinoculating the HR with excess sludge from the SAMBR when the SRT of the SAMBR wasgreater than 45 days. Among the bacterial species Ruminococcus flavefaciens, Spirochaeta,Sphingobacteriales, Hydrogenophaga, Ralstonia, Prevotella and Smithella were associated withgood reactor performances.
19
Pattanayak, Soubhagya Kumar. "Exploration of fouling propensity in an anaerobic membrane bioreactor treating municipal wastewater and comparison to that of an aerobic membrane bioreactor". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/32050.
Testo completoAbstract (sommario):
Anaerobic biodegradation is a successful technology that has been used in
industrial, food processing, and agricultural wastewater treatment for many decades. The
operational costs associated with anaerobic systems are typically lower than with aerobic
systems and anaerobic systems also generate less waste sludge. However, the application
of anaerobic treatment systems is limited for low strength wastewaters in colder climates.
In colder climates, the biomass growth yield and the growth rate are relatively low,
resulting in a low net biomass production. To maintain adequate biomass concentration in
an anaerobic bioreactor, membrane modules can be coupled to the reactor to effectively
treat low strength wastewater in colder climates. One of the important advantages of the
membrane bioreactors (MBRs) is that the membrane component of the system can retain
virtually all of the biomass within the bioreactor. Membrane units in an anaerobic MBR
can operate either as external units or as submerged units, depending on the requirements
of the process. Currently, the application of submerged AnMBRs is limited as compared
to external AnMBRs. However, the vacuum-driven submerged membrane process shows
a lot of promise as compared to external membrane processes. This is because high
energy consumption is one of the biggest limiting factors in external membranes. Also,
the use of head space gas for reducing fouling in submerged anaerobic membranes can be
a very successful technology in limiting energy consumption in bioreactors. However, the
widespread use of membrane technology has been limited due to the fouling of the
membrane fibers. Membrane fouling is an inherent problem with membrane processes,
which not only affects the long term operational stability, but also leads to significant
operational costs due to increased membrane replacement frequency and added energy
consumption. Therefore, a considerable amount of research and engineering effort has
been devoted to understanding the mechanisms of membrane fouling and to work out
fouling prevention and control strategies.
The broad objective of the present study was (1) to assess the treatment
performance of a submerged membrane AnMBR treating low strength municipal wastewater at an ambient temperature and (2) to identify and characterize the fouling
mechanism in the AnMBR.
The anaerobic process was effective in removing chemical oxygen demand
(COD) and volatile fatty acid (VFA) from the effluent VFA removal was essentially
complete and 80% COD removal was achieved under acetate-supplemented conditions.
Nonetheless, high concentration of effluent COD (i.e. 72 mg/L) indicated that aerobic
post treatment is needed to achieve secondary quality effluent.
On-line filtration studies were conducted simultaneously on both the anaerobic
membrane and the aerobic membrane of membrane enhanced biological phosphorus
removal (MEBPR) process. The on-line tests were conducted to compare the fouling
mechanism in the anaerobic membrane process and the aerobic membrane process. The
results from energy dispersive X-ray (EDX) analysis suggest that inorganic materials
were not the prominent foulants in the AnMBR. Also, scanning electron microscopy
(SEM) analysis indicated that very little microbial colonization was found in the
anaerobic membranes.
Mixed liquor characterization tests were conducted to verify the role of extracellular
polymeric substances (EPS) on membrane fouling. The tests concluded that the
total bound EPS concentration was higher in the aerobic mixed liquor and the total
soluble EPS concentration was higher in the anaerobic mixed liquor. The high soluble
EPS concentration was probably the reason for rapid fouling of anaerobic membranes. In
addition, the higher SRT in the case of the anaerobic membrane bioreactor might be
responsible for the high soluble EPS production observed in some studies.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
20
Suhaimi, Hazwani. "Glucose diffusivity in tissue engineering membranes and scaffolds : implications for hollow fibre membrane bioreactor". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/18297.
Testo completoAbstract (sommario):
Unlike thin tissues (e.g., skin) which has been successfully grown, growing thick tissues (e.g., bone and muscle) still exhibit certain limitations due to lack of nutrients (e.g., glucose and oxygen) feeding on cells in extracapillary space (ECS) region, or also known as scaffold in an in vitro static culture. The transport of glucose and oxygen into the cells is depended solely on diffusion process which results in a condition where the cells are deprived of adequate glucose and oxygen supply. This condition is termed as hypoxia and leads to premature cell death. Hollow fibre membrane bioreactors (HFMBs) which operate under perfusive cell culture conditions, have been attempted to reduce the diffusion limitation problem. However, direct sampling of glucose and oxygen is almost impossible; hence noninvasive methods (e.g., mathematical models) have been developed in the past. These models have defined that the glucose diffusivity in cell culture medium (CCM) is similar to the diffusivity in water; thus, they do not represent precisely the nutrient transport processes occurring inside the HFMB. In this research, we define glucose as our nutrient specie due to its limited published information with regard to its diffusivity values, especially one that corresponds to cell/tissue engineering (TE) experiments. A series of well-defined diffusion experiments are carried out with TE materials of varying pore size and shapes imbibed in water and CCM, namely, cellulose nitrate (CN) membrane, polyvinylidene fluoride (PVDF) membrane, poly(L-lactide) (PLLA) scaffold, poly(caprolactone) (PCL) scaffold and collagen scaffold. A diffusion cell is constructed to study the diffusion of glucose across these materials. The glucose diffusion across cell-free membranes and scaffolds is investigated first where pore size distribution, porosity and tortuosity are determined and correlated to the effective diffusivity. As expected, the effective diffusivity increases correspondingly with the pore size of the materials. We also observe that the effective glucose diffusivity through the pores of these materials in CCM is smaller than in water. Next, we seeded human osteoblast cells (HOSTE85) on the scaffolds for a culture period of up to 3 weeks. Similar to the first series of the diffusion experiments, we have attempted to determine the effective glucose diffusivity through the pores of the scaffolds where cells have grown at 37°C. The results show that cell growth changes the morphological structure of the scaffolds, reducing the effective pore space which leads to reduced effective diffusivity. In addition, the self-diffusion of glucose in CCM and water has also been determined using a diaphragm cell method (DCM). The results have shown that the glucose diffusivity in CCM has significantly reduced in comparison to the water diffusivity which is due to the larger dynamic viscosity of CCM. The presence of other components and difference in fluid properties of CCM may also contribute to the decrease. We finally employ our experimentally deduced effective diffusivity and self-diffusivity values into a mathematical model based on the Krogh cylinder assumption. The glucose concentration is predicted to be the lowest near the bioreactor outlet, or in the scaffold region, hence this region becomes a location of interest. The governing transport equations are non-dimensionalised and solved numerically. The results shown offer an insight into pointing out the important parameters that should be considered when one wishes to develop and optimise the HFMB design.
21
Melamane, Xolisa. "Cleaning of fouled membranes using enzymes from a sulphidogenic bioreactor". Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1015764.
Testo completoAbstract (sommario):
Maintenance of membrane performance requires inevitable cleaning or defouling of fouled membranes. Membrane cleaning using enzymes such as proteases, lipases, α-glucosidases from a sulphidogenic bioreactor was investigated. At first, dilute and concentrated enzyme extract were prepared form the sulphidogenic pellet. Enzyme assays on 0.5 % azocaisen, 1 % triacetin and 1 mg/ml ρ-nitrophenyl-α-D-glucopyranoside were performed using the concentrated enzyme extract (0 – 200 mg/ml). For membrane fouling, an abattoir effluent was obtained from Ostritech Pty (Ltd), Grahamstown, South Africa. The effluent was characterised for presence of potential foulants such as lipids, proteins, amino acids and carbohydrates. Static fouling of polysulphone membranes (0.22 μm, 47 mm) was then performed using the abattoir effluent. Cleaning of the fouled membranes was also performed using at first the dilute and then the concentrated form (200 mg/ml) of enzyme extracts. Qualitative and quantitative biochemical analysis for proteins, lipids and carbohydrates was performed to ascertain the presence of foulants on polysulphone membranes and their removal by dilute or concentrated enzyme extracts. The ability of dilute enzyme extracts to remove proteins lipids, and carbohydrates fouling capillary UF membrane module; their ability to restore permeate fluxes and transmembrane pressure after cleaning/defouling was also investigated. Permeate volumes from this UF membrane module were analysed for protein, amino acids, lipids, and carbohydrates concentrations after fouling and defouling. Fouling was further characterized by standard blocking, cake filtration and pore blocking models using stirred UF cell and polyethersulphone membranes with MWCO of 30 000, 100 000 and 300 000. After characterization of fouling, polyethersulphone membranes with MWCO of 30 000 and 300 000 were defouled using the concentrated enzyme extract (100 mg ml). Enzyme activities at 200 mg/ml of enzyme concentration were 8.071 IU, 86.71 IU and 789.02 IU for proteases, lipases and α-glucosidases. The abattoir effluent contained 553 μg/ml of lipid, 301 μg/ml of protein, 141 μg/ml of total carbohydrate, and 0.63 μg/ml of total reducing sugars. Proteins, lipids and carbohydrates fouling polysulphone membranes after a day were removed by 23.4 %, when a dilute enzyme was used. A concentrated enzyme extract of 200 mg/ml was able to remove proteins, lipids and carbohydrates up to 5 days of fouling by 100 %, 82 %, 71 %, 68 % and 76 % respectively. Defouling of dynamically fouled capillary ultrafiltration membranes using sulphidogenic proteases was successful at pH 10, 37°C, within 1 hour. Sulphidogenic proteases activity was 2.1 U/ml and flux Recovery (FR %) was 64. Characterization of fouling revealed that proteins and lipids were major foulants while low concentration of carbohydrates fouled polyethersulphone membranes. Fouling followed standard blocking for 10 minutes in all the membranes; afterwards fouling adopted cake filtration model for membranes with 30 000 MWCO and pore blocking model for membranes with 300 000 MWCO. A concentration of 100 mg/ml of enzyme extract was able to remove fouling from membranes with MWCO of 30 000. Defouling membranes that followed pore blocking model i.e. 300 000 MWCO was not successful due to a mass transfer problem. From the results of defouling of 30 000 and 300 000 MWCO it was concluded that defouling of cake layer fouling (30 000 MWCO) was successful while defouling of pore blocking fouling was unsuccessful due to a mass transfer problem. The ratio of enzymes present in the enzyme extract when calculated based on enzymatic activity for proteases, lipases and α-glucosidases was 1.1 %, 11 % and 87.9 %. It was hypothesized that apart from proteases, lipases, α and β-glucosidases; phosphatases, sulphatases, amonipeptidases etc. from a sulphidogenic bioreactor clean or defoul cake layer fouling by organic foulants and pore blocking fouling provided the mass transfer problem is solved. However, concentration of enzymes from a sulphidogenic bioreactor has not been optimized yet. Other methods of concentrating the enzyme extract can be investigated for example use of organic solvents.
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Abegglen, Christian Konrad. "Membrane bioreactor technology for decentralized wastewater treatment and reuse /". Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17998.
Testo completo
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Puzanov, Taya. "Continuous production of lactic acid in a membrane bioreactor". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0019/MQ49724.pdf.
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Strachan, Laura Fay. "The Extractive Membrane Bioreactor : flux enhancement and biofilm control". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266892.
Testo completo
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Palmer, S. M. "Development of a dialysis membrane bioreactor for beverage dealcoholisation". Thesis, Swansea University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638402.
Testo completoAbstract (sommario):
The objective of this work was to remove ethanol from an alcoholic beverage using the aerobic biochemistry of the yeast Saccharomyces cerevisiae and a Dialysis Membrane as an anaerobic/aerobic barrier, between this yeast and the potable beverage. Ethanol, as the carbon substrate is then delivered to the yeast cells by molecular diffusion. To assess the uptake of ethanol as a sole carbon substrate, several stirred tank fermenter (STF) experiments were carried out, with various starting conditions, in particular initial yeast biomass concentration and cell population age. This work showed the benefits of a high initial biomass concentration to minimise batch process time by increasing the rate of bioreaction, mass transfer limitations at the membrane interfacial area having essentially been engineered out in the design of the system, as reported. The benefit of high yeast biomass concentrations are proposed to be dependent on a specific ethanol concentration factor, (per yeast cell), termed the Specific Exposure Factor, (SEF). Through mathematical models developed in this work, mass transfer and bioreaction rates have been assessed, the controlling step being quantified by the dimensionless Kaliber Number (Ka). Through the use of developed dimensionless plots, and comparison of the Monod kinetic parameters given by the models presented, a study of yeast biomass growth and ethanol substrate utilisation is made. Whilst the suppression of yeast growth kinetic performance on ethanol substrate was somewhat variable in the Membrane Bioreactor, the variance did not affect the ethanol substrate uptake kinetic performance of the aerobic yeast cells, which remained remarkably consistent. Ethanol utilisation, (as the limiting carbon substrate), is shown to be by inhibited passive transport at the yeast cell membrane. A comparison of ethanol substrate metabolism to that of glucose has been made.
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Wong, Hiu Man. "Removal of pathogens by membrane bioreactor : removal efficiency, mechanisms and influencing factors /". View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20WONGH.
Testo completoAbstract (sommario):
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 93-102). Also available in electronic version. Access restricted to campus users.
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Valadez-Blanco, Rogelio. "A membrane bioreactor for biotransformations to synthesise hydrophobic chiral molecules using organic solvent nanofiltration membranes". Thesis, Imperial College London, 2008. http://hdl.handle.net/10044/1/11535.
Testo completo
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Zahir, Nayar. "On-line optimisation of backflush duration in a membrane bioreactor using hollow fibre ultrafiltration membranes". Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323586.
Testo completo
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Liu, Wenjun. "High strength industrial wastewater treatment using membrane bioreactors : a novel extractive membrane bioreactor for treating bio-refractory organic pollutants in the presence of high concentrations of inorganics: application to acidic effluents". Thesis, University of Bath, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369997.
Testo completo
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Ntwampe, Seteno Karabo Obed. "A perfluorocarbon-based oxygen delivery system to a membrane bioreactor". Thesis, [S.l. : s.n.], 2009. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1059&context=td_cput.
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Ho, Jae Ho. "Anaerobic membrane bioreactor for the treatment of low strength wastewater". [Ames, Iowa : Iowa State University], 2007.
Cerca il testo completo
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Verrecht, Bart. "Optimisation of a hollow fibre membrane bioreactor for water reuse". Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/6779.
Testo completoAbstract (sommario):
Over the last two decades, implementation of membrane bioreactors (MBRs) has increased due to their superior effluent quality and low plant footprint. However, they are still viewed as a high-cost option, both with regards to capital and operating expenditure (capex and opex). The present thesis extends the understanding of the impact of design and operational parameters of membrane bioreactors on energy demand, and ultimately whole life cost. A simple heuristic aeration model based on a general algorithm for flux vs. aeration shows the benefits of adjusting the membrane aeration intensity to the hydraulic load. It is experimentally demonstrated that a lower aeration demand is required for sustainable operation when comparing 10:30 to continuous aeration, with associated energy savings of up to 75%, without being penalised in terms of the fouling rate. The applicability of activated sludge modelling (ASM) to MBRs is verified on a community-scale MBR, resulting in accurate predictions of the dynamic nutrient profile. Lastly, a methodology is proposed to optimise the energy consumption by linking the biological model with empirical correlations for energy demand, taking into account of the impact of high MLSS concentrations on oxygen transfer. The determining factors for costing of MBRs differ significantly depending on the size of the plant. Operational cost reduction in small MBRs relies on process robustness with minimal manual intervention to suppress labour costs, while energy consumption, mainly for aeration, is the major contributor to opex for a large MBR. A cost sensitivity analysis shows that other main factors influencing the cost of a large MBR, both in terms of capex and opex, are membrane costs and replacement interval, future trends in energy prices, sustainable flux, and the average plant utilisation which depends on the amount of contingency built in to cope with changes in the feed flow.
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Wei, Chunliang. "Nutrient removal and fouling reduction in electrokinetic membrane bioreactor at various temperatures". Water Science. & Technology, 2009. http://hdl.handle.net/1993/31635.
Testo completoAbstract (sommario):
With the aim of mitigating membrane fouling, an electrocoagulation (EC) based electrokinetic membrane bioreactor (EMBR) was developed and operated with real municipal wastewater under low temperatures. Both batch tests and continuous EMBR experiments demonstrated the significant advantages in membrane fouling reduction over the conventional antifouling strategies, ushering its potential applications as an attractive hybrid MBR technology for decentralized wastewater treatment in remote cold regions. The main research observations and findings could be summarized as follows: (1). Effective membrane fouling mitigation at low temperatures was due to destruction of extracellular polymeric substances (EPS) and subsequent reduction of the biocake resistance. The transmembrane pressure (TMP) increased at a much slower rate in EMBR and the filtration resistance was about one third of the control MBR prior to chemical cleaning cycle; (2). A new membrane parameter, the specific fouling rate (SFR) was proposed, relating the fouling rate with permeate flux and temperature-dependent viscosity. Pore clogging and biocake resistances were quantified for the first time with the same membrane module and operating conditions as in regular MBR, rather than resorting to the use of batch filtration setups; (3). The floc size in EMBR did not increase as a result of the air scouring shear force and decrease in the extracellular polymeric substances (EPS); (4). When current intensity was less than 0.2 A, polarity reversal had minimal impact on electrode passivation reduction due to insignificant hydrogen yield, however, if current intensity was above 0.2 A, frequent polarity reversal (< 5 min per cycle) was detrimental to electrode passivation if no sufficient mixing was provided; (5). Viability of the microorganisms in the EMBR system was found to be dependent on duration of the current application and current density. The bacterial viability was not significantly affected when the applied current density was less than 6.2 A/m2; (6). Significant abiotic ammonification was found in electrocoagulation (EC). DO in the treated liquid was depleted within an hour, under the anaerobic condition in EC, nitrate was chemometrically reduced to ammonium following a two-step first order reaction kinetics. Aeration (DO > 2 mg/L) was shown effective in suppressing abiotic ammonification; (7). Magnetic resonance imaging (MRI) technology was used for the first time as an in-situ non-invasive imaging tool to observe membrane fouling status in an EMBR.October 2016
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Smith, Shaleena. "Pilot assessment of Novel Membrane Bioreactor Processes - Improvements in Biological Nutrient Removal and Membrane Operation". Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3357.
Testo completoAbstract (sommario):
With increasing water reuse applications and upcoming stringent regulations for treated wastewater effluent discharge, wastewater plants need to consider alternative technologies beyond conventional treatment processes. The new regulations, Numeric Nutrient Criteria (NNC), may regulate discharge nitrogen and phosphorus concentrations to as low as 0.5 mg/L as N and 10 μg/L as P respectively. To meet these target requirements, system retrofitting to incorporate chemical or advanced nutrient removal systems possibly with membrane technology will most likely be required. Although microfiltration/ultrafiltration membranes coupled with biological processes, otherwise known as membrane bioreactors (MBR), remove contaminants and suspended solids, nutrient removal is minimal to none. This emphasizes the importance of the biological process in MBRs. This study evaluated and tested the improvement of biological nutrient removal (BNR) in an MBR system which can meet NNC regulations along with the optimization of membrane operation for the reduction of fouling and energy consumption.
A pilot study was conducted at the City of Tampa wastewater treatment plant and was divided into four phases of experimentation using two submerged MBR membranes operated with modified biological configurations. Laboratory analyses and data collection were conducted during the experiments and the performance evaluated for each configuration. System configurations were also optimized throughout each phase of testing for nutrient removal. Important factors used in the development of an appropriate configuration included isolation of the membrane tank from the biological reactors in the design, control of the dissolved oxygen (DO) concentrations or specifically the oxidation reduction potential (ORP) during operation and appropriate internal recirculation rates between the reactors.
The results of this study provided information relevant for the assessment of both the BNR process and membrane performance. Membrane performance data indicated the importance and effect of air scouring (despite energy consumption) on membrane fouling for long-term stable flux operation as well as the cleaning frequency whether chemical enhanced backwash (CEB) or clean-in-place (CIP). This assessment also discussed how BNR systems can be enhanced through the incorporation of important design factors to eliminate the inhibiting factors of nitrogen and phosphorus removal such as dissolved oxygen. One of the biological processes tested in this study achieved effluent nitrogen and phosphorus concentrations below 5 mg/L and 1 mg/L respectively. Although the process tested did not meet NNC criteria, it can be applied with chemical precipitation. This, in turn, can reduce the operating and maintenance (O&M) costs associated with the chemical precipitation of phosphorus.
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Alkmim, Aline Ribeiro. "Membrane Bioreactor for treating petroleum refinery effluent: treatment performance, membrane fouling mechanism and fouling control". Universidade Federal de Minas Gerais, 2015. http://hdl.handle.net/1843/BUBD-9Y2HVT.
Testo completoAbstract (sommario):
The work developed discusses the potential use of MBR to treat refinery effluent and operational strategies that may mitigate fouling. At first, MBR performance was evaluated in terms of pollutants removal and fouling investigation in conditions of shock load. The results demonstrated that MBR was able to reduce effectively the pollutants, meeting guideline standards of disposal and reuse for non-potable ends. FTIR results showed that organic matter was removed by biological oxidation and/or retained by adsorption in the biological sludge or retention in the UF membrane. Furthermore, SMP was produced during treatment. In terms of membrane permeability, the results showed that the soluble fraction of mixed liquor contributed significantly to membrane fouling due to the presence of SMP fraction. Secondly, the sludge filterability was studied as an important parameter to evaluate sludge properties and the potentiality of membrane fouling in MBR. Three filterability assessment methods described in the literature were compared regarding their capability to sense sludge quality variation and reproducibility treating petroleum refinery effluents. This study showed that, among the methods evaluated, Time To Filter was the most effective to assess the filterability both in terms of its capability to detect sludge quality variation and reproducibility. The results have also shown that filterability is directly related to membrane fouling potential, and can be used as a tool to monitor and control fouling process in MBR. Significant filterability correlations among colloidal TOC, EPS and floc size were found. The third study assessed the long-term use of cationic polyelectrolyte to improve the sludge filterability, as well as membrane fouling control in bioreactor membrane while treating refinery effluents. Corrective and preventive cationic polyelectrolyte dosages have been added to the MBR in order to evaluate the membrane fouling mitigation in both strategies. The results have confirmed that the use of this product increased sludge filterability, and reduced membrane fouling. During monitoring time stress events occurred due to increase in oil and grease and phenol concentrations in the MBR feed. The preventive use of cationic polyelectrolyte allowed a more effective and stable sludge filterability with lower consumption without decreasing MBR pollutant removal overall performance.O trabalho desenvolvido aborda o uso do BRM tratando efluente de petróleo e estratégias operacionais que possam minimizar a incrustação. Primeiramente, avaliou-se o desempenho do BRM em termos de remoção de poluentes e investigou-se o comportamento da incrustação em ocorrências de cargas de choque. Os resultados demonstraram que o BRM foi capaz de reduzir efetivamente os poluentes, alcançando padrões de descarte e reuso. Os resultados de IV mostraram que a matéria orgânica é removida por oxidação biológica e/ou retenção por adsorção no lodo biológico ou retenção pela membrana. Além disso, verificou-se que o SMP é produzido durante o tratamento. Em relação à permeabilidade da membrana, verificou-se que a fração solúvel do lodo biológico contribui significativamente para a incrustação da membrana devido a presença de SMP. No segundo estudo a filtrabilidade do lodo foi estudada como um importante parâmetro para a avaliação das propriedades do lodo e o potencial de incrustação da membrana em BRM. Foram comparados três métodos de determinação da filtrabilidade relatados na literatura em termos de capacidade de detecção de variações da qualidade do lodo e da reprodutibilidade, avaliando a aplicação deste parâmetro como ferramenta para o monitoramento e controle de incrustação de BRM. O estudo mostrou que o método Time To Filter foi o mais eficiente para medição da filtrabilidade, tanto em termos de capacidade de detecção de variação da qualidade do lodo, como em reprodutibilidade. Verificou-se também que a filtrabilidade está diretamente relacionada ao potencial de incrustação na membrana. Encontraram-se correlações significativas da filtrabilidade com os parâmetros COT coloidal, EPS e tamanho de floco. No terceiro estudo, avaliou-se a utilização de um polieletrólito catiônico a fim de melhorar a filtrabilidade do lodo e consequentemente controlar a incrustação da membrana. Dosagens corretiva e preventiva do polieletrólito foram realizadas nos BRM a fim de avaliar o melhor controle da incrustação nas duas estratégias. Os resultados confirmaram que o uso do produto aumenta a filtrabilidade do lodo e reduz a incrustação da membrana. Durante o período de monitoramento ocorreram choques de carga com altas concentrações de óleos e graxas e fenol na alimentacão. O uso preventivo do polieletrólito catiônico permitiu uma filtrabilidade mais efetiva e estável sem prejudicar o desempenho do BRM quanto à remoção de poluentes.
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Barghi, Hamidreza. "Functionalization of Synthetic Polymers for Membrane Bioreactors". Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3688.
Testo completoAbstract (sommario):
Membrane bioreactors (MBRs) show great promise for productivity improvement and energy conservation in conventional bioprocesses for wastewater reclamation. In order to attain high productivity in a bioprocess, it is crucial to retain the microorganisms in the bioreactors by preventing wash out. This enables recycling of the microorganisms, and is consequently saving energy. The main feature of MBRs is their permeable membranes, acting as a limitative interface between the medium and the microorganisms. Permeation of nutrients and metabolites through the membranes is thus dependent on the membrane characteristics, i.e. porosity, hydrophilicity,and polarity. The present thesis introduces membranes for MBRs to be used in a continuous feeding process, designed in the form of robust, durable, and semi-hydrophilic films that constitute an effective barrier for the microorganisms, while permitting passage of nutrients and metabolites. Polyamide 46 (polytetramethylene adipamide), a robust synthetic polymer, holds the desired capabilities, with the exception of porosity and hydrophilicity. In order to achieve adequate porosity and hydrophilicity, bulk functionalization of polyamide 46 with different reagents was performed. These procedures changed the configuration from dense planar to spherical, resulting in increased porosity. Hydroxyethylation of the changed membranes increased the surface tension from 11.2 to 44.6 mJ/m2. The enhanced hydrophilicity of PA 46 resulted in high productivity of biogas formation in a compact MBR, due to diminished biofouling. Copolymerization of hydrophilized polyamide 46 with hydroxymethyl 3,4-ethylenedioxythiophene revealed electroconductivity and hydrophilic properties, adequate for use in MBRs. To find either the maximal pH stability or the surface charge of the membranes having undergone carboxymethylation, polarity and the isoelectric point (pI) of the treated membranes were studied by means of a Zeta analyzer. The hydroxylated PA 46 was finally employed in a multilayer membrane bioreactor and compared with hydrophobic polyamide and PVDF membranes. The resulting biogas production showed that the hydroxylated PA 46 membrane was, after 18 days without regeneration, fully comparable with PVDF membranes.
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Abdullah, Syed Zaki. "Investigation of effect of dynamic operational conditions on membrane fouling in a membrane enhanced biological phosphorus removal process". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/264.
Testo completoAbstract (sommario):
The membrane bioreactor (MBR) is becoming increasingly popular for wastewater treatment, mainly due to its capability of producing high quality effluent with a relatively small footprint. However, high plant maintenance and operating costs due to membrane fouling limit the wide spread application of MBRs. Membrane fouling generally depends on the interactions between the membrane and, the activated sludge mixed liquor, which in turn, are affected by the chosen operating conditions. The present research study aimed to explore the process performance and membrane fouling in the membrane enhanced biological phosphorus removal (MEBPR) process under different operating conditions by, (1) comparing two MEBPRs operated in parallel, one with constant inflow and another with a variable inflow, and by, (2) operating the MEBPRs with different solids retention times (SRT).
On-line filtration experiments were conducted simultaneously in both MEBPR systems by using test membrane modules. From the transmembrane pressure (TMP) data of the test membrane modules, it was revealed that fouling propensities of the MEBPR mixed liquors were similar in both parallel reactors under the operating conditions applied, although the fouling propensity of the aerobic mixed liquors of both reactors increased when the SRT of the reactors was reduced.
Routinely monitored reactor performance data suggest that an MEBPR process with a varying inflow (dynamic operating condition) performs similarly to an MEBPR process with steady operating conditions at SRTs of 10 days and 20 days. Mixed liquor characterization tests were conducted, including critical flux, capillary suction time (CST), time to filter (TTF) and, bound and soluble extracellular polymeric substances (EPS) were quantified, to evaluate their role on membrane fouling. The tests results suggest that the inflow variation in an MEBPR process did not make a significant difference in any of the measured parameters.
With decreased SRT, an increase in the concentrations of EPS was observed, especially the bound protein, and the bound and soluble humic-like substances. This suggests that these components of activated sludge mixed liquors may be related to membrane fouling. No clear relationship was observed between membrane fouling and other measured parameters, including critical flux, normalized CST and normalized TTF.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
38
Abdullah, Syed. "Investigation of effect of dynamic operational conditions on membrane fouling in a membrane enhanced biological phosphorus removal process". Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/264.
Testo completoAbstract (sommario):
The membrane bioreactor (MBR) is becoming increasingly popular for wastewater treatment, mainly due to its capability of producing high quality effluent with a relatively small footprint. However, high plant maintenance and operating costs due to membrane fouling limit the wide spread application of MBRs. Membrane fouling generally depends on the interactions between the membrane and, the activated sludge mixed liquor, which in turn, are affected by the chosen operating conditions. The present research study aimed to explore the process performance and membrane fouling in the membrane enhanced biological phosphorus removal (MEBPR) process under different operating conditions by, (1) comparing two MEBPRs operated in parallel, one with constant inflow and another with a variable inflow, and by, (2) operating the MEBPRs with different solids retention times (SRT).
On-line filtration experiments were conducted simultaneously in both MEBPR systems by using test membrane modules. From the transmembrane pressure (TMP) data of the test membrane modules, it was revealed that fouling propensities of the MEBPR mixed liquors were similar in both parallel reactors under the operating conditions applied, although the fouling propensity of the aerobic mixed liquors of both reactors increased when the SRT of the reactors was reduced.
Routinely monitored reactor performance data suggest that an MEBPR process with a varying inflow (dynamic operating condition) performs similarly to an MEBPR process with steady operating conditions at SRTs of 10 days and 20 days. Mixed liquor characterization tests were conducted, including critical flux, capillary suction time (CST), time to filter (TTF) and, bound and soluble extracellular polymeric substances (EPS) were quantified, to evaluate their role on membrane fouling. The tests results suggest that the inflow variation in an MEBPR process did not make a significant difference in any of the measured parameters.
With decreased SRT, an increase in the concentrations of EPS was observed, especially the bound protein, and the bound and soluble humic-like substances. This suggests that these components of activated sludge mixed liquors may be related to membrane fouling. No clear relationship was observed between membrane fouling and other measured parameters, including critical flux, normalized CST and normalized TTF.
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Ivanovic, Igor. "Application of biofilm membrane bioreactor (BF-MBR) for municipal wastewater treatment". Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13395.
Testo completoAbstract (sommario):
The biofilm membrane reactor (BF-MBR) is a wastewater treatment system that combines biological wastewater treatment with a biofilm process and with membrane separation for clarification and purification of biologically treated wastewater. Work in this thesis is experimentally based on laboratory pilot scale systems specially built, developed and modified for the research purposes in this thesis. The work in this thesis is presented through six main themes (research chapters (RC)): RC1: Overview of previous research on knowledge on particle separation in a movingbed-biofilm reactor (MBBR) process RC2: Overview of previous research on membrane bioreactors (MBR) based on attached (biofilm) growth. RC3: Results from empirical studies on the influence of aeration on membrane performances in the BF-MBR RC4: Results from mathematical and empirical studies on influence of membrane reactor design on membrane performances in the BF-MBR RC5: Results from empirical studies on influence of nitrogen removal on membrane performances in the BF-MBR RC6: Results from empirical studies on influence of coagulation and flocculation on overall performances in the BF-MBR The main contributions (C) are: C1: An overview of the research literature on empirical studies of knowledge on MBR with biofilm implementations and separation techniques in the movingbed-biofilm reactor C2: Proposing a method for defining optimum aeration rates for the membrane unit based on minimizing the amount of submicron particles. C3: Improvement in membrane performances by changing the membrane reactor geometry. C4: Demonstration of feasibility of sustainable operation of proposed system with biological nitrogen removal treatment configurations. C5: Improvement of membrane and overall process performance with addition of different additives. Results from the research work in this thesis are based on five main empirical studies using a pilot scale biofilm MBR (BF-MBR) setup where overall system performance and membrane performance has been studied. The thesis is structured as a paper collection based on seven papers, where the first two are review papers and other five are results of the original research. In addition, there are three publications based on original research from the study that were published during the early stages of the project studies, presented only with the references and abstracts as secondary papers.En biofilm membran reaktor (BF-MBR) er et rensesystem for avlopsvann som kombinerer biologisk rensing ved bruk av en biofilm prosess, og med membranseparasjon for filtrering og rensing av det biologisk renset avlopsvannet. Denne avhandlingen er basert pa eksperimentelle arbeider med pilot enheter og laboratoriesystemer som er spesielt bygd, utviklet og modifisert for forskningsformalene i dette studiet. Arbeidet i denne avhandlingen er presentert gjennom seks hovedtema (forskning kapitler (FK)): FK1: Oversikt over tidligere forskning og kunnskap om partikkelseparasjon i en moving-bed-biofilm reaktor (MBBR) prosess FK 2: Oversikt over tidligere forskning pa membran bioreaktorer (MBR) basert pa vekst av fastsittende biomasse (biofilm). FK 3: Resultater fra empiriske studier om hvordan lufting pavirker membranens prosessegenskaper i en BF-MBR FK 4: Resultater fra matematiske og empiriske studier om hvordan membranreaktor design pavirker membranens separasjonsegenskaper i en BF-MBR FK 5: Resultater fra empiriske studier om hvordan membranprosessen pavirkes av nitrogenfjerning i en BF-MBR FK 6: Resultater fra empiriske studier om hvordan koagulering og flokkulering pavirker den generelle prosessen i en BF-MBR De viktigste bidragene (B) er: B1: En oversikt over forskningslitteratur om empiriske studier og kunnskap om MBR med anvendelse av biofilm prosesser og separasjon teknikker brukt i en movingbed-biofilm reaktor B2: Foreslag pa en metode for a definere optimal lufting for membranenheten basert pa a minimere mengden av sub-mikron partikler. B3: Forbedring i membranens ytelsesevne ved a endre pa membranreaktorens geometri. B4: Demonstrasjon av mulighetene for en barekraftig drift av foreslatte system med konfigurasjoner av biologisk nitrogenfjerning. B5: Forbedring av bade membran og generelle prosessytelser ved bruk av forskjellige tilsetningsstoffer. Resultater fra forskningsarbeidet i denne avhandlingen er basert pa fem empiriske studier utfort med en pilot biofilm MBR (BF-MBR) apparatur, der generelle systemytelse og membranytelse er studert. Avhandlingen er strukturert som en samling av syv publikasjoner, der de to forste er ”review” artikler og folgende fem artikler er resultatene fra original forskningen. I tillegg er tre publikasjoner basert pa original forskning fra studiet som ble publisert i en tidlig fase av arbeidet presentert som sekundare artikler, kun angitt med referanser og sammendrag.
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Chen, Wen. "A membrane bioreactor(MBR) for an innovative biological nitrogen removal process". Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39557959.
Testo completo
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Sarin, Vikrant. "Wastewater treatment using membrane bioreactor". Thesis, 2013. http://localhost:8080/xmlui/handle/12345678/6700.
Testo completo
42
Tu, Sung-Han, e 杜松翰. "Membrane Fouling Mechanism and Cleaning in Submerged Membrane Bioreactor". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/2c8nvk.
Testo completoAbstract (sommario):
碩士國立交通大學
環境工程系所
92
At the past years, custom wastewater biological treatment’s operation range is limited by “sludge settling properties”, but recently a new technology called “membrane bioreactor process”, it use the membrane unit to substitute sediment tank, so can largely enhance treatment performance. Otherwise, its effluent have potential achieve high level water reuse requirement. But it also has the disadvantage of membrane fouling. The fouling behavior in this process may include inorganic, organic, biofouling, much complex than the past study of single fouling, so this study focus on the fouling mechanism, fouling stage, fouling effect factor and membrane cleaning four points in this complex couple-fouling process. In our study, we use rapid plate membrane instrument as main equipment, the acclimated sludge get from wastewater plant as feed system. Using filtration data couple with past fouling model, finds it occurs pore blocking, intermediate and cake filtration mechanism. And, fouling stage goes on pore blocking and then transfer to intermediate and cake filtration, this is incorporate with other fouling research. The fouling effect factor discuss in this study include transmembrane pressure (TMP), cross-flow velocity (CFV), fouling matter’s size distribution and membrane characteristic. Results reveal the relationship between fouling matter’s size distribution and membrane pore size determines main fouling mechanism. Upper critical flux operation, fouling becomes more serious when increasing TMP. CFV influence the cake’s form stabilization and properties, so it plays an important role in the mid and former fouling stage. Membrane cleaning is another topic in this study. Ultrasonic cleaning result shows its cleaning target transfer from cake to weak attached foultants in membrane pores differ from different fouling level. Chemical cleaning experiment were carried out in central composite design (CCD), using chemical concentration and cleaning time as two discussion factors, only thirteen operation runs can effectively get the useful cleaning efficiency information include response surface, contour plot and best cleaning condition. In our different cleaning aim target experiment, we use citric acid aim to inorganic fouling and NaOCl aim to organic couple with biofouling. Result shows the cleaning efficiency limitation factor is significant different. But it still not confirms what fouling type is the key limitation to cleaning.
43
Lee, Hsinchieh, e 李信杰. "Fouling Characteristics of MF membrane in Submerged Membrane Bioreactor". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/00483814800745345367.
Testo completoAbstract (sommario):
碩士國立交通大學
環境工程系所
94
By replacing a secondary clarifier with a membrane unit in an activated sludge process (ASP), membrane bioreactors (MBRs) have emerged as one of the innovative solutions for wastewater treatment and reclamation. The application of MBR is constrained by membrane fouling. Fouling leads to permeate flux decline and transmembrane pressure (TMP) increase, resulting in more frequent membrane cleaning and replacement which increase the operating cost. This study is to investigate the mechanism of membrane fouling. The lab-scale MBR was operated under sub-critical flux. The fouling rate of the MBR was very low. However, with the increase in filamentous bacteria, an abrupt rise in fouling rate was observed along with the increased sludge viscosity and polysaccharides in extracellular polymeric substances (EPS) suggesting their close relationship. Cake resistance (Rc) was the dominant resistance in batch filtration tests. The increase in total resistance (Rt) and Rc and the decrease in pore resistance (Rf) with increasing membrane permeability suggested that the cake formed on the membrane surface hindered the penetration of smaller particulates inside the membrane pores. Although increasing hydraulic shear stress could effectively reduce the Rt and Rc, the Rf increased due to the reduced cake barrier. The relative contributions of SS (Rss), colloid (Rcol) and solutes (Rsol) toward total resistance were 62 %, 31 % and 7 %, respectively. Hydrodynamic control was a powerful method to mitigate macroscopic fouling (RAS), but it could not prevent the deposition of soluble macromolecules (Rss). Despite the choice of filtration at sub-critical flux, fouling was experienced due to the effect of soluble macromolecules.
44
Rollings-Scattergood, Sasha Michael. "Comparison between Hybrid Moving Bed Membrane Bioreactor and Conventional Membrane Bioreactor Processes in Municipal Wastewater Treatment". Thesis, 2011. http://hdl.handle.net/10214/3170.
Testo completoAbstract (sommario):
A conventional membrane bioreactor (MBR) and two moving bed bioreactors coupled with ultrafiltration membrane filtration were operated for close to six months to investigate biological nutrient removal and potential fouling inducing parameter mitigation. Unique to one of the moving bed membrane bioreactors (MBMBR) was a newly designed media that incorporated a hydrodynamic exterior carrier with a highly porous interior packing. Preliminary investigation indicates that nitrogen compounds were superiorly removed in the two MBMBRs when compared with the MBR. This is a result of denitrification processes occurring in anoxic micro-zones found within the depths of the biofilm affixed to media. Fouling propensity was found to be increased by over four times in the MBMBR systems as compared to the MBR. Mixed liquor, permeate and filtrate analysis, membrane fibre examination and permeability tests indicated that colloidal organic carbon, as well as soluble microbial products were the dominant fouling inducing compounds.Manuscript format
The Natural Sciences and Engineering Research Council of Canada
45
Chang, Wei-Yun, e 張維運. "Critical flux determination of membrane bioreactor". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/16382161782970447101.
Testo completoAbstract (sommario):
碩士中原大學
土木工程研究所
96
The application of membrane bioreactor (MBR) for the wastewater treatment has gain more advantages recently. However, membrane fouling need to be consider for it’s industrial application. The major parameter which controls the fouling rate.Many study indicated that membrane fouling can be effectively decrease by operating MBR system below critical flux. In the study , the experiment was done uder two batch condition to study the effect of different hydrophobicity of PTFE membrane (CYCU R&D Center for Membrane Technology) and different MLSS concentration on TMP and flux. Long-term performance of reactor was tested using five methods evaluate critical flux under real operation.The effect of different SRT on sludge characteristics and critical flux was also studied.The result showed that the critical flux determined using different methods was different.The critical flux was slighty affected by membrane hydrophobicity at lower MLSS concentration ( <4,000 mg/L) and it was negative at higher MLSS concentration ( >4,000 mg/L). The MBR system can be operated over 30 days by fouling rate and permeability methods due to it’s low fouling rate and below 10 days by other methods. The membrane fouling was observed to be much higher at a short SRT as compared to longer SRT. The result showed that longer SRT the rate of fouling was lower maybe due to lower EPS concentration and higher particle size distribution.
46
Deowan, Shamim Ahmed, Enrico Drioli, Raffaele Molinari, Alberto Figoli e Jan Hoinkis. "Development of membrane bioreactor (MBR) process applying novel low fouling membranes". Thesis, 2013. http://hdl.handle.net/10955/772.
Testo completoAbstract (sommario):
Dottorato di Ricerca in "Ingegneria Chimica e dei Materiali" Ciclo XXVISSD, a.a. 2013Water is a part and parcel of human life. Water contaminated from industry and agriculture with heavy metal ions, pesticides, organic compounds, endocrine disruptive compounds, nutrients (phosphates, nitrates, nitrites) has to be effi-ciently treated to protect humans from being intoxicated with these compounds or with bacteria. Clean water as basis for health and good living conditions is too far out of reach for the majority of the population in the world (Bionexgen, 2013). Water recycling is now widely accepted as a sustainable option to re-spond to the general increase of the fresh water demand, water shortages and for environmental protection. Water recycling is commonly seen as one of the main options to provide remedy for water shortage caused by the increase of the water demand and draughts as well as a response to some economical and environmental drivers. The main options for wastewater recycling are industri-al, irrigation, aquifer recharge and urban reuse (Pidou, M., 2006). Among the industrial wastewaters, the textile industry is long regarded as a water intensive sector, due to its high demand of water for all parts of its pro-cedures. Accordingly, textile wastewater includes quite a large variety of con-tents, chemicals, additives and different kinds of dyestuffs. The main environ-mental concern with this waste water is about the quantity and quality of the water discharged and the chemical load it carries. To illustrate, for each ton of fabric products, 20 – 350 m3 of water are consumed, which differs from the color and procedure used. The quality of the textile wastewater depends much on the employed coloring matters, dyestuffs, accompanying chemicals, as well as the process itself (Brik et al., 2006). MBR technology is recognised as a promising technology to provide water with reliable quality for reuse. It provides safely reuse water for non-potable use. But the treated textile wastewater by MBR technology alone can’t comply with the reuse or discharge standard in many countries due to its colouring matters and dyestuffs remained in the effluent, if otherwise, MBR is associated with other technology like NF, RO, other processes or the applied membrane is modified or a novel MBR is applied. Fouling is another limiting factor for worldwide application of MBR technology especially in high-strength industri-al wastewater like textile wastewater. Moreover, membrane fouling is regarded as the most important bottleneck for further development of MBR technology. It is the main limitation for faster development of this process, particularly when it leads to flux losses that cleaning cannot restore (Howell et al. 2004). In this thesis work, a novel membrane bioreactor (MBR) process was devel-oped by modifying a applied commercial PES UF membrane in MBR module by nano-structured novel coating through polymerisable bicontinuous micro-emulsion (PBM) process with the purpose of having higher hydrophilicity and low fouling propensity. Before starting the MBR experiments, some characteri-sation tests such as SEM, AFM images analysis, roughness measurements, pore geometry, contact angel, standard salt rejections, model textile dye rejec-tions were performed. In addition, fouling tests using two laboratory cross flow testing units were conducted as well. To reach the ultimate goal of research, 6 sheets of novel coated membranes with size of 30 cm × 30 cm were prepared and these were used to prepare a three-envelope MBR module of 25 cm × 25 cm in size (total membrane area 0.33 m2) similar to that of a commercially available three-envelope PES UF MBR module. This novel MBR module was tested in a submerged lab-scale MBR pilot plant (tank volume ca. 60 L) for about 6 months using model textile dye wastewater (MTDW) as test media for all experiments with the aim of having uniform compositions with respect to time. The tests were done based on carefully selected operation conditions. Prior to testing of the novel membrane module MBR, experiments were carried out with a commercial PES UF MBR module using the same pilot plant set up and the same selected operating conditions for about 10 months. After comple-tion of trials with the novel coated MBR module, similar experiments were carried out again with a commercial PES UF MBR module to check the simi-larity of the biological sludge conditions and other operation conditions as well. In short, the sequences of the experiments were as follows: Commercial PES UF MBR (10 months) →novel membrane coated MBR (6 months)→PES UF MBR (1.5 months) The ultimate goal of the experiments was to compare the results between the commercial MBR and novel coated MBR module in order to demonstrate im-provement regarding fouling propensity and permeate water quality. The performance analysis shows that the novel coated MBR module compared to the commercial MBR module has 7% points higher COD removal efficien-cy, 20% points higher blue dye removal efficiency, high antifoul-ing/antimicrobial properties, resulting in a very low-fluctuating and highly ro-bust MBR process which looks promising with regard to economic viability. Since the newly developed MBR module worked excellent on laboratory scale it consequently should be deployed at an industrial site to be tested with real ii wastewater. Therefore, this novel three-envelope MBR module is on the way to be tested with real wastewater in a textile factory in Tunisia. The findings of these on-site pilot trials will serve as a basis for further improvement and even-tually pilot trails with larger membrane area will be addressed
Università della Calabria
47
Su, Bo-Rung, e 蘇柏融. "Microalgae Harvesting in a Membrane Bioreactor with Disc UF Membrane". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/33188652510936833620.
Testo completoAbstract (sommario):
碩士東海大學
環境科學與工程學系
103
Membrane ultrafiltration (UF) method is a simply separation method which is usually used for microalgae harvesting. However, membrane fouling is an important problem that decreases the performance of microalgae harvesting. The aim of this research is study of different disc-type UF membrane filtrations (400B and 400HB) on harvesting of two different microalgae (Spirulina maxima and Scenedesmus obliquus), to investigate the optimum operating parameters for filtration-remediation process. Moreover, cause of membrane fouling was also studied in this research. The result indicated that 400HB membrane predominantly shows higher efficiency of membrane filtration than 400B membrane, corresponded with initial resistance, reversible resistance and irreversible resistance owning to higher porosity. Scenedesmus obliquus causes slower membrane fouling because of its smaller sizes and can be easily remediated than Spirulina maxima. The membrane fouling can also be caused by the polysaccharides and proteins from broken cells also not only for the cells, confirmed by FTIR study. It was found that fouling process can be temporized up to 20 % when applied aeration system during filtration process. Backwash cleaning method is the most effective cleaning method and the flux decline can be completely recovered when combining aeration with backwash cleaning method. Keywords: microalgae, UF, harvesting
48
Sowe, Alieu, e Alieu Sowe. "Application of Nanosilver Coated Membrane Bioreactor for Mitigating Membrane Biofouling". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/va7vha.
Testo completoAbstract (sommario):
碩士國立臺北科技大學
環境工程與管理研究所
106
The application of silver nanoparticles (AgNPs) for mitigating membrane biofouling in a novel microfiltration membrane bioreactor (MF-MBR) system was proposed for wastewater treatment, and reuse and to simultaneously reduce membrane biofouling, achieve high water quality, and less energy consumption. Membrane biofouling has become a serious drawback limiting the wider spread and application of the membrane technology. Membrane bioreactor is a wastewater treatment technology that combine the activated sludge process with micro- and ultrafiltration and is widely regarded as an effective tool for municipal and industrial water treatment and reuse due to stable operation performance, high product water quality, reduction in excess sludge production, reduction of risk of substances, effluent reuse, and low footprint. Membrane bioreactors technology offers a competitive advantage over conventional wastewater treatment systems however, the impediment of the MBR technology is the high rate of membrane fouling problems consequently resulting to reduction in productivity and higher membrane replacement and operating cost. Hence, this study aims to identify the major foulants and the principal fouling mechanisms such as concentration polarization, inorganic precipitation, pore blocking, organic adsorption, cake formation and biological fouling. The study is also aimed at investigating the different phenomena of membrane fouling during the membrane application in the MBR system for wastewater treatment. This study used silver nanoparticles (AgNPs, nanosilver) to mitigate membrane biofouling potentials in which a microfiltration (MF) membrane was used. The MF membrane modules were modified with nanosilver through the use of surface coating of the AgNPs on the surface of the membrane, to fix the silver nanoparticles on the membrane by a novel chemical reduction approach. The modified membranes for any alterations in antimicrobial properties, permeability, and silver leaching were examined. The membrane bioreactor was operated in good conditions to ensure a suitable environment for the bacterial growth. The MLSS and MLVSS of the system were 14860 mg MLSS/L and 11345 mg MLVSS/L respectively, with an optimum pH range of 6.5 to 8. The system had an approximate COD, PO43--P and NH4+-N removal percentage of 99.7%, 97.8% and 99.4% respectively and the volume of permeate collected per day approximates to 6 L/d in combination of the two operating membrane modules, the M-AgNPs and the M-plain membranes had an average water flux of 5.33 L/m2 h and 5.15 L/m2 h respectively. The results analysis to determine the mitigation of biofouling by the nanosilver coated membrane was performed with the water flux variation test, the SEM and EDS analysis, pressure variation test, and the ABT and VST analysis, in which all proofed positive for using the silver nanoparticles, having great antimicrobial effects in mitigating membrane biofouling. The results revealed that the nanosilver modified membrane showed slightly higher permeability than the unmodified membrane. The results from this study also confirmed that silver leaching from the silver modified membrane was minimal and insignificant according the ICP analysis from the batch tests conducted, which was lower than the international standard for the maximum contaminant limit (MCL) of silver in wastewater and water treatment applications, established by the United States Environmental Protection Agency (USEPA) and the World Health Organization (WHO) at 0.1 mg/L which was compatible and acceptable. The results from the experiment also successfully revealed that the modified membrane with AgNPs displayed great antimicrobial properties thus, mitigated membrane biofouling.
49
Huang, Tsung-Han, e 黃宗涵. "Identification of protein foulant in membrane bioreactor". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/10804258581492725193.
Testo completoAbstract (sommario):
碩士中原大學
土木工程研究所
97
Development of membrane bioreactors has been limited by problems of membrane fouling, which will decrease the flux but increase the TMP (trans-membrane pressure) and cost for maintenance and operation. Many literature has indicated the major constituent of fouling is extracellular polymeric substances(EPS) which is composed by protein, carbohydrate, humic substances, nucleic acid and lipid. And,the most part of EPS is protein. Recently, many research has aimed at the quantitative analysis of protein in order to find out the relationship between protein and membrane fouling. However, no research focuses on the qualitative analysis of protein. Therefore, this research set membrane of different material(PAN,PVDF,PTFE) in the reactor, and performed biological technique to identify the species of proteins on fouling and discuss the relativity of protein and materials. Results showed the surface morphology of membrane(pore formation, size, roughness) will affect the forming of fouling.We analyzed the distribution of the molecular weight of protein and found out the membranous surface with larger pores will cause higher ratio of small protein to aggregate. There is no significant connection between species of proteins and hydrophilicity or hydrophobicity of surface , while hydrophobic protein aggregated on the surface more easier than hydrophilic protion. The location of 29%~58% of protein with functions relation to translation. More than 67% of protein located within bacteria, this may be related to the lysis of bacteria. We will apply our research to identity surface foulant of membranes and reduce fouling effect on MBR.
50
Lin, Ching-Chieh, e 林敬傑. "Treatment and Recovery of membrane bioreactor (MBR) effluent by membrane processes". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/yjnsqq.
Testo completoAbstract (sommario):
碩士國立中央大學
環境工程研究所
96
The purpose of this research is to evaluate the feasibility of water reuse treated by UF and RO membrane processes. The processes treat four types of membrane bioreactor (MBR) effluent, containing synthetic dye wastewater (SDW), domestic wastewater (DW), food processing wastewater (FPW) and organic wastewater form TFT-LCD industry (TFT-LCD). Simultanesously, the mechanism for RO process for the rejection of contaminants in SDW is also supposed. The result shows that there is slight suspend solid in the effluent of MBR, and the major contaminants are salt and solute organic substances which almost consist of Soluble Microbial Product (SMP) in the effluent of MBR. Because of complex feedwater chemistry and distinct MBR process, the molecular weight distribution of SMP in MBR effluent and in traditional biological process is different. However membrane process can remove the residual solute organic substances and salt efficiently. The conductivity, TOC and TS removal efficiencies of SDW, DW and TFT-LCD RO permeate are 85~98%, 85~94% and 94~99%. For FPW permeate, the rejections of UF/RO process in terms of conductivity, TOC and TS are 91.1%, 93.8% and 90.9%, respectively. In addition, the rejection of RO membrane for SMP which have large molecular weight is efficient. According to the experiment treating SDW by RO, we find out that slight organic substances are accumulated on RO membrane. Because of the slight blocking phenomenon of RO membrane, we simulate the permeate water quality and the permeate flux by solution diffusion model to prove that solution diffusion is the major mechanism for RO process for the rejection of contaminants in SDW. The result show that the calculated concentration values in permeate are within ±30% of the experimental, so that solution diffusion model can be considered the major mechanism. Due to the small extent polarization concentration phenomenon on membrane surface, the TOC model results are tiny lower than the TOC experimental results. In order to find the potential of application and feasibility of RO process, the long-term investigation try to analysis the pilot treatment cost of DW. The cost for DW is 28 NT/ton and the permeate can reuse to the semiconductor Ⅳ water and the feed of pure water machine. So RO process has competitive advantage to treat MBR effluent to reuse.